Technical Field

The invention relates to a galvanic plating apparatus and a method of galvanically plating a component carrier structure.

Background Art

In the context of growing product functionalities of component carriers equipped with one or more electronic components and increasing miniaturization of such electronic components as well as a rising number of electronic components to be mounted on the component carriers such as printed circuit boards, increasingly more powerful array-like components or packages having several electronic components are being employed, which have a plurality of contacts or connections, with ever smaller spacing between these contacts. Removal of heat generated by such electronic components and the component carrier itself during operation becomes an increasing issue. At the same time, component carriers shall be mechanically robust and electrically reliable so as to be operable even under harsh conditions.

When galvanically plating electrically conductive structures of a component carrier, it may be desired but difficult to obtain a well-defined thickness or thickness distribution.

Summary of the Invention

It is an object of the invention to allow manufacture of a component carrier with well-defined thickness or thickness distribution of electrically conductive structures.

In order to achieve the object defined above, a galvanic plating apparatus and a method of galvanically plating a component carrier structure according to exemplary embodiments of the invention is provided. According to an exemplary embodiment of the invention, a galvanic plating apparatus for galvanically plating a component carrier structure is provided, wherein the galvanic plating apparatus comprises an anode split into a plurality of separate anode parts, each configured for providing a separate current density (in particular an individually controllable current density, separately and independently from the current densities of the other anode part or parts) to an assigned section of the component carrier structure, for providing a spatially dependent current density profile over an extension of the component carrier structure to be galvanically plated.

According to another exemplary embodiment of the invention, a method of galvanically plating a component carrier structure is provided, wherein the method comprises splitting an anode into a plurality of separate anode parts, and providing, by each anode part, a separate current density to an assigned section of the component carrier structure for providing a spatially dependent current density profile over an extension of the component carrier structure to be galvanically plated.

In the context of the present application, the term "component carrier" may particularly denote any support structure which is capable of accommodating, directly or indirectly, one or more components thereon and/or therein for providing mechanical support and/or electrical connectivity. In other words, a component carrier may be configured as a mechanical and/or electronic carrier for components. In particular, a component carrier may be one of a printed circuit board, an organic interposer, and an IC (integrated circuit) substrate. A component carrier may also be a hybrid board combining different ones of the above-mentioned types of component carriers.

In the context of the present application, the term "component carrier structure" may particularly denote a physical structure comprising one or a plurality of component carriers, or preforms thereof. For example, a component carrier structure may be a component carrier itself. It is also possible that a component carrier structure comprises a plurality of component carriers, for instance an array of component carriers or a panel comprising component carriers. Furthermore, it is also possible that a component carrier structure is a structure obtained during manufacturing component carriers, for example a panel or an array comprising a plurality of preforms of component carriers which may still be integrally connected.

In the context of the present application, the term "galvanic plating" may particularly denote electroplating of metal, in particular copper, using water based solutions (which may also be denoted as electrolytes) containing the metal to be deposited as ions (for example in the form of dissolved metal salts). An electric field may be applied during galvanic plating between an anode and an at least partially electrically conductive work piece in form of a component carrier structure which may function as cathode or which may be electrically connected with a cathode. Consequently, positively charged metal ions may be forced to move to the cathode-type component carrier structure where they give up their charge and deposit themselves as metal on the surface of the component carrier structure. Hence, the ions will be forced by the electric field and the applied potential to take up negative charged electrons provided by the cathode. During galvanic plating, a direct current (DC) may be applied between anode and cathode. This may allow to accomplish galvanic plating in a quick and efficient way. However, it may also be possible to execute galvanic plating by applying a pulsed current (in particular a current profile having alternating pulses with positive and negative sign), wherein short phases of pulses with negative sign may cause temporary metal removal rather than metal deposition, for instance a compensate overplating. When using a pulsed current profile, homogeneity of the thickness of the deposited metal (in particular copper) on the surface of the component carrier structure may be improved. Exemplary embodiments of the invention may use any of direct current galvanic plating and pulsed galvanic plating of component carrier structures. Hence, a galvanically deposited metal structure on a component carrier structure may be formed by electroplating or galvanic plating. One or more plating stages may be carried out for adjusting the thickness of the galvanically deposited metal layer, and in particular for optionally forming a plurality of sub-layers of the galvanically deposited metal layer.

In the context of the present application, the term "anode" may particularly denote an electrode immersed in a plating bath during galvanic plating. The anode may be the electrode to which a first (for instance positive) voltage or current is applied (at least over a major part of the plating process). In contrast to this, a cathode may denote another electrode used during galvanic plating and being electrically connected to the component carrier structure to be plated during the galvanic plating process. The cathode may be the electrode to which a second (for example negative) voltage or current is applied (at least over a major part of the plating process). The anode may be defined as the electrode where an oxidation reaction happens.

Correspondingly, the cathode may be defined as the electrode where a reduction reaction happens.

In the context of the present application, the term "anode parts configured for providing a separate current density" may particularly denote electrically separate portions of a common galvanic plating anode which may be configured so that separate electric currents with different current density may be applied to different ones of the anode parts. Current density may denote an amount of charge per time that flows through an area of a chosen cross section. Electric current density may be measured in amperes per square meter. In particular, the different anode parts may have electrically separate supply lines to a current source or a rectifier so that different values of the current density and different values of an absolute current may be selected and applied to the individual anode parts. For example, a control unit may be provided for controlling a current source and the anode parts correspondingly. In the context of the present application, the term "providing a spatially dependent current density profile over an extension of the component carrier structure" may particularly denote that the component carrier structure is arranged spatially distanced and relatively to the anode parts so that different portions of the component carrier structure being spatially aligned with corresponding anode parts experience different plating current values so as to be plated with different plating efficiency. There may be no direct physical contact between anode parts and the component carrier structure to avoid an electrical short. For example, the mentioned spatial relationship between portions of the component carrier structure and anode parts may be adjusted during a motion of a component carrier structure along a galvanic plating line or while being (temporarily or permanently) stationary at a certain position of the galvanic plating line. For instance in a scenario in which a specification of component carriers to be manufactured based on the component carrier structure requires different metal densities in different portions of the component carrier, the application of the same current density to the entire component carrier structure may cause inhomogeneity of the copper thickness distribution. A more homogeneous copper thickness distribution over the component carrier structure may thus be achieved by selecting different current densities for different anode parts.

According to an exemplary embodiment of the invention, galvanically plating a component carrier structure may be carried out using an anode which is split into plural individual anode parts. Each of said anode parts may be electrically connected to a current source so as to be controllable so provide an individual current density which may be selected differently for different anode parts and independently from current densities of other anode parts. Each anode part may be spatially assigned to a corresponding portion or section of the component carrier structure to be plated, so that an individual current density may be applied to each section of the component carrier structure during galvanic plating. Since the component carrier structure may function as cathode or may be electrically connected to a cathode during the electroplating process, efficiency of galvanic metal deposition on different sections of the component carrier structure may be adjusted differently as a consequence of the different current densities of the various anode parts.

Hence, an intrinsic, design-related and/or artifact-caused inhomogeneity of the efficiency of copper deposition in different sections of a component carrier structure may be at least partially balanced or equilibrated by a corresponding current density profile provided by the individually powerable anode parts. Descriptively speaking, an inhomogeneity of metal deposition efficiency of different sections of the component carrier structure may be at least partially compensated by an inverse inhomogeneity of metal deposition efficiency set by the anode parts providing a correspondingly adjusted spatially dependent current density profile. By providing a spatially dependent current density profile over an extension of the component carrier structure to be galvanically plated, copper thickness distribution over the extension of the component carrier structure may be rendered more homogeneous or at least more precisely definable. Advantageously, this may allow to avoid both overplating and underplating of various sections of the component carrier structure. As a consequence, the yield of manufactured component carriers may be increased by reducing galvanic plating-related defects, and the reliability of the obtained component carriers may be improved. A further advantageous technical effect of exemplary embodiments is that dedicated areas or sections may have different roughness compared to others. For example, some areas may be shiny, whereas others may be dull. Advantageously, this may be used for further manufacturing stages (in particular what concerns adhesion).

In the following, further exemplary embodiments of the galvanic plating apparatus and the method will be explained.

In an embodiment, the galvanic plating apparatus comprises a control unit configured for separately controlling the current density applied to each of the anode parts. For example, such a control unit may be configured for carrying out an algorithm defining the time dependency and/or spatial dependency of the current applied to the various anode parts during a plating process. A corresponding control unit may thereby balance out metal thickness inhomogeneity caused by undesired phenomena in a scenario in which the entire anode provides the same current density.

In an embodiment, the control unit is configured for controlling the anode for adjusting the spatially dependent current density profile so that different sections of the component carrier structure are individually galvanically plateable with different plating parameters. In particular, a plating current and thereby plating efficiency may be controlled to be higher in a section of the component carrier structure showing an intrinsically lower plating efficiency, as compared with another section of the component carrier structure showing an intrinsically higher plating efficiency and being therefore subjected to an anode part with lower plating current.

In an embodiment, the control unit is configured for controlling the anode for adjusting the spatially dependent current density profile based on temperature and/or pH value in a plating bath. For instance, temperature and/or pH value in the plating bath may be detected by a corresponding sensor. Since electrochemical reactions may be strongly dependent on temperature and pH inside the electrolyte bath, one or more pH and/or temperature sensors may be foreseen. In particular, electric potential and/or current may be adjusted in accordance with a sensed pH value and/or a sensed temperature parameter. In an embodiment, the control unit is configured for dynamically controlling the current density applied to each of the anode parts, in particular in a timedependent manner. Advantageously, the spatially dependent current density profile may be dynamically adjusted. Thus, the control unit may control the anode parts so that their individually adjusted current densities vary over time. For instance in a scenario in which a component carrier structure is moved along a plating line and thereby passes a stationary anode, the current density of each individual anode part may be adjusted over time so that, at each point of time, the presently assigned section of the component carrier structure is subjected to a correspondingly adjusted current density of the presently assigned anode part. It is also possible that, after a first part of the galvanic plating process, an inhomogeneous thickness distribution of plated metal over the extension of the component carrier structure is determined, for instance detected and/or modelled. In such a scenario, the spatially dependent current density profile created by the anode parts and their separate current densities may be selectively modified for at least partially compensating the determined inhomogeneity.

In an embodiment, the control unit is configured for controlling the anode parts and additionally at least one subtractive process for removing metal from the component carrier structure (then, a portion of the component carrier may be also part of the anode). Such a subtractive process may be a process which removes part of the metal from the component carrier structure. For instance, such a subtractive process may be etching or mechanically grinding. It is also possible that such a subtractive process forms part of the galvanic plating process with reverse current, for instance in terms of pulse plating. In a scenario of an inhomogeneous metal distribution, there may be sections of the component carrier structure with higher deposition rate (for instance sections with less target metal area according to a specification). To balance out such phenomena at least partially, a negative current may be applied temporarily by individual ones of the anode parts being spatially assigned to such sections of the component carrier structure which may lead to temporary metal removal in such sections. By taking this measure, local overplating may be suppressed.

In an embodiment, the control unit is configured for controlling the anode parts and additionally at least one additive process for applying metal to the component carrier structure to thereby provide a predefined, in particular homogeneous, distribution of metal on the component carrier structure. In a scenario of an inhomogeneous metal distribution, there may be sections of the component carrier structure with lower deposition rate (for instance sections with more target metal area according to a specification). To balance out such phenomena at least partially, an additional additive process may be executed for locally thickening metal in such sections of the component carrier structure. For example, such an additional additive process may be a further galvanic plating stage selectively only on such sections of the component carrier structure. It may also be possible to add metal in a spatially dependent manner on certain sections of the component carrier structure by electroless deposition, sputtering, chemical deposition of metal, etc. By taking this measure, local underplating may be avoided.

In an embodiment, the control unit is configured for controlling the current density applied to each of the anode parts to thereby form a metal pattern on the component carrier structure in accordance with a predefined target specification. For example, the design of component carriers (for instance printed circuit boards) to be manufactured may be stored in a design file including data defining said target specification concerning a plurality of parameters for a manufacturing process. Said design file may also comprise information about shape and position as well as target thickness of a metal pattern of the component carriers. The control unit may access information indicative of said predefined design (for instance may access the above mentioned design file) and may execute the galvanic plating process and in particular the control of the split anode parts as well as their individual current densities accordingly.

In an embodiment with a galvanostatic plating mode, the current density may be fixed, whereas the applied electric potential may be varied. However, it is also possible in an embodiment that the electric potential is fixed and the current density is varied (which may be denoted as a potentiostatic plating mode).

In an embodiment, the control unit is configured for controlling the current density applied to each of the anode parts to thereby form a metal pattern on the component carrier structure with homogeneous thickness. This may also include a process of filling cavities and/or through holes. Hence, a control goal of the control unit may be to achieve the same thickness of a metal pattern over the entire component carrier structure. In order to achieve this control goal, an intrinsically spatially dependent metal plating efficiency in different sections of the component carrier structure may be taken into account. In particular, this may include the consideration of the phenomenon that an actually obtained metal thickness may depend on a ratio of a metallized surface area and an entire surface area of a certain section of the component carrier structure according to a predefined specification. Usually, higher metal thickness is obtained in regions with a lower ratio, and vice versa. The control unit may calculate and apply a spatially dependent current density profile of the anode parts for compensating this phenomenon, i.e. providing higher current density profile in sections of the component carrier structure where the ratio is higher.

In an embodiment, the control unit is configured for applying different electric potentials to different anode parts. Thus, different electric voltages may be present at different anode parts in relation to the cathode constituted by the component carrier structure.

In an embodiment, different anode parts have different partial areas. By providing different anode parts with different partial areas, a further design parameter for creating a spatially dependent metal deposition efficiency profile is provided.

In an embodiment, the galvanic plating apparatus comprises a plurality of galvanic plating tanks through which the component carrier structure is to be conveyed sequentially during galvanically plating, wherein at least one, in particular each, of the galvanic plating tanks comprises an anode split into a plurality of separate anode parts. For instance, a component carrier structure to be galvanically plated can be sequentially moved through a plurality of galvanic plating tanks. For instance, galvanization may be initiated after imaging a component carrier structure with a dry film corresponding to a metal pattern to be formed by galvanic deposition. Thereafter, one or a plurality of galvanic plating stages may be executed in one or in a number of serially arranged galvanic plating tanks, for instance to execute copper plating. After that, it may be possible to form a surface finish, for instance by plating a thin layer of tin over the galvanically plated copper. One, some or all of said galvanic plating tanks may be equipped with a split anode providing a spatially dependent current density profile. This may promote a homogeneous metal deposition in each individual galvanic plating tank. Moreover, this may advantageously also allow a later galvanic plating tank to adjust its current density profile of its split anode for compensating an inhomogeneous metal deposition of a previous galvanic plating tank.

Before treatment of a component carrier structure in one or more galvanic plating tanks, the component carrier structure may be subjected to preprocessing, such as cleaning and/or micro-etching. After treatment of a component carrier structure in one or more galvanic plating tanks, the component carrier structure may be subjected to post-processing, for example rinsing and/or drying.

In an embodiment, at least some of the anode parts are chevron-shaped. Hence, a chevron-pattern may be created by the anode parts. An example of such a design is shown in Figure 4. Such a chevron-shaped design of anode parts of a split anode or of a plurality of serially arranged split anodes has turned out as highly appropriate for triggering homogeneous metal deposition. By such a chevron shape, it has turned out to be possible to properly influence boundary parts between different sections of a panel-type component carrier structure.

In an embodiment, at least some of the anode parts have at least one zig zag edge. Again, reference is made to Figure 4 showing such a zig zag edge. A zig zag edge may be formed by a sequence of connected straight edge portions with an alternating sequence of inwardly and outwardly tapered edge portions. For instance, an inwardly or outwardly tapering angle of such an edge portion may be less than 30°, in particular less than 20°, measured in relation to a linear edge (for instance extending along a conveying direction of the component carrier structure). In an embodiment, the anode split into the anode parts has an overall rectangular shape. Even when individual anode parts are provided with chevron-shape and/or with zig zag edges, the anode as a whole (i.e. formed by the anode parts as constituents) may have a rectangular shape. Said rectangular shape may correspond to a rectangular shape of a component carrier structure (in particular a panel) subjected to galvanic plating using said anode. This may contribute to a homogeneous plated metal thickness over the extension of the component carrier structure.

In an embodiment, the anode is split into the plurality of separate anode parts in and/or transverse to a conveying direction along which the component carrier structure is to be conveyed during galvanically plating. For instance, one or more component carrier structures (for example four panel-type component carrier structures) may be mounted on one or more support structures and may be conveyed through one or more galvanic plating tanks. The support structure may create an electric connection of the at least one component carrier structure to an electric power supply or a rectifier. When mounted on the support structure, the at least one component carrier structure may then act as cathode in the plating process. When conveyed through the one or more galvanic plating tanks, the component carrier structure may pass anode parts being arranged along the conveying direction of the component carrier structure and/or anode parts being arranged perpendicular to the conveying direction. Hence, creation of a spatially dependent current density profile may be accomplished along and/or transverse to the conveying direction. This may allow to further refine the galvanic plating process and in particular its capability of creating homogeneously thick metallic structures over the entire extension of the component carrier structure.

In an embodiment, the galvanic plating apparatus comprises a cathode to be electrically coupled with the component carrier structure to be galvanically plated, and at least one current source configured for applying a current with selectable current density distribution between the anode and the cathode. The cathode may be electrically coupled with an electrically conductive structure of the component carrier structure so that also the component carrier structure may function as a cathode during the electroplating process. If metal is removed from the component carrier structure by a reverse current (see the above-described subtractive process), the component carrier structure may temporarily act as anode. Optionally, the component carrier may include an electrically decoupled part, an anode portion and a cathode portion inside the component carrier structure to prevent creating a short circuit when applying the current.

In an embodiment, a number of anodes and a number of cathodes may be different. Hence, there may be different numbers of cathodes and anodes. Alternatively, there may be the same number of cathodes and anodes.

In an embodiment, the galvanic plating apparatus comprises a conveyor mechanism for conveying the component carrier structure along the anode, in particular along at least part of serially arranged anode parts. Such a conveyor mechanism may also drive a support structure (such as one or more fly-bars) on which a component carrier structure or a plurality of component carrier structures may be mounted during the galvanic plating process. The conveyor mechanism may for instance be configured for providing a motion force to the support structure or the component carrier structure.

In an embodiment, the conveyor mechanism is configured for conveying the component carrier structure in a horizontal orientation along at least some of the anode parts, in particular along a direction parallel with respect to the orientation of the anode parts. Preferably, plate-shaped component carrier structures (such as panels) may be oriented horizontally during the galvanic plating process in the galvanic plating apparatus. The split anode parts may then be arranged above or below and parallel to the horizontally oriented component carrier structure. Alternatively, it is also possible to carry out galvanic plating using split anode parts with a component carrier structure being oriented vertically during galvanic plating treatment in the galvanic plating apparatus.

In an embodiment, the control unit is configured for or the method comprises controlling the anode for providing a more homogeneous thickness distribution of plated metal on the component carrier structure compared with a spatially independent current density over the extension of the component carrier structure. Thus, the current distribution over the extension of the anode may be selected with a spatially dependent profile in accordance with a control scheme which reduces inhomogeneity of the galvanic plating metal thickness distribution over the component carrier structure.

Alternatively, the control unit may be configured for or the method comprises controlling the anode for providing metallic structures with different heights in vertical direction (for instance on dedicated locations in the component carrier structures). For instance, it may be desired that one area on the panel should have double the thickness of copper to be plated compared to a different area. This may adjusted by the split anode configuration as well. Although a gist of an exemplary embodiment may be to create copper structures with low or no copper thickness distribution, there may also be applications in which it may be desired to create intentionally a distinct copper thickness distribution, i.e. different metallic thicknesses in different regions of a component carrier structure.

In an embodiment, the control unit is configured for or the method comprises determining information indicative of a metal distribution over the component carrier structure to be galvanically plated, and adjusting or re-adjusting the spatially dependent current density profile over the extension of the component carrier structure to decrease a thickness variation of the metal distribution over the component carrier structure.

In one alternative of the previously described embodiment, a metal distribution over the component carrier structure, which can be expected when executing a galvanic plating process, can be theoretically modeled or calculated before actually executing the galvanic plating process using the galvanic plating apparatus with the split anode parts. Such a theoretical modeling or calculation may also take into account a specification of the component carriers to manufactured based on the processed component carrier structure. Said specification may in particular include information concerning a metallic pattern on the surface of the component carrier structure to be formed by the galvanic plating process. In the context of such a theoretical determination of an expected metal distribution, also expert rules and/or empirical data can be considered. For instance it may be considered that regions of a component carrier structure to be galvanically plated for forming metallic structures of higher density may show a lower galvanically plated metal thickness in comparison with other regions of the component carrier structure to be galvanically plated for forming metallic structures of lower density which may show a higher galvanically plated metal thickness. When such a theoretical determination indicates that an inhomogeneous galvanically plated metal thickness distribution is to be expected, an adjustment of the spatially dependent current density profile of the split anode parts may be carried out for rendering the thickness distribution more balanced. For instance, anode parts facing portions of the component carrier structure with metallic structures of higher density may be subjected to a higher current density than other anode parts facing portions of the component carrier structure with metallic structures of lower density.

In another alternative of the previously described embodiment, a physical measurement of a thickness distribution of galvanically deposited metal after part of the galvanic plating process may be executed. For instance, such a measurement may be carried out as an optical measurement and/or as an electric measurement and/or in form of a visual inspection by an operator. Thereafter, a spatially dependent current density profile of the split anode parts may be re-adjusted for balancing out a measured thickness distribution in the subsequent part of the galvanic plating process.

In an embodiment, the component carrier structure comprises a panel, an array or a component carrier, in particular a printed circuit board. The component carrier may comprise a stack comprising at least one electrically insulating layer structure and/or at least on electrically conductive layer structure. The at least one electrically conductive layer structure may be connected to an electrode (in particular a cathode, or an anode).

In an embodiment, a stack of the component carrier structure or of the component carrier comprises at least one electrically insulating layer structure and at least one electrically conductive layer structure. For example, the component carrier may be a laminate of the mentioned electrically insulating layer structure(s) and electrically conductive layer structure(s), in particular formed by applying mechanical pressure and/or thermal energy. The mentioned stack may provide a plate-shaped component carrier capable of providing a large mounting surface for further components and being nevertheless very thin and compact. In an embodiment, the component carrier structure or component carrier is shaped as a plate. This contributes to the compact design, wherein the component carrier nevertheless provides a large basis for mounting components thereon. Furthermore, in particular a naked die as example for an embedded electronic component, can be conveniently embedded, thanks to its small thickness, into a thin plate such as a printed circuit board.

In an embodiment, a component carrier obtained from the component carrier structure is configured as one of the group consisting of a printed circuit board, a substrate (in particular an IC substrate), and an interposer.

In the context of the present application, the term "printed circuit board" (PCB) may particularly denote a plate-shaped component carrier which is formed by laminating several electrically conductive layer structures with several electrically insulating layer structures, for instance by applying pressure and/or by the supply of thermal energy. As preferred materials for PCB technology, the electrically conductive layer structures are made of copper, whereas the electrically insulating layer structures may comprise resin and/or glass fibers, so-called prepreg or FR.4 material. The various electrically conductive layer structures may be connected to one another in a desired way by forming holes through the laminate, for instance by laser drilling or mechanical drilling, and by partially or fully filling them with electrically conductive material (in particular copper), thereby forming vias or any other through-hole connections. The filled hole either connects the whole stack, (through-hole connections extending through several layers or the entire stack), or the filled hole connects at least two electrically conductive layers, called via. Similarly, optical interconnections can be formed through individual layers of the stack in order to receive an electro-optical circuit board (EOCB). Apart from one or more components which may be embedded in a printed circuit board, a printed circuit board is usually configured for accommodating one or more components on one or both opposing surfaces of the plateshaped printed circuit board. They may be connected to the respective main surface by soldering. A dielectric part of a PCB may be composed of resin with reinforcing fibers (such as glass fibers).

In the context of the present application, the term "substrate" may particularly denote a small component carrier. A substrate may be a, in relation to a PCB, comparably small component carrier onto which one or more components may be mounted and that may act as a connection medium between one or more chip(s) and a further PCB. For instance, a substrate may have substantially the same size as a component (in particular an electronic component) to be mounted thereon (for instance in case of a Chip Scale Package (CSP)). In another embodiment, the substrate may be substantially larger than the assigned component (for instance in a flip chip ball grid array, FCBGA, configuration). More specifically, a substrate can be understood as a carrier for electrical connections or electrical networks as well as component carrier comparable to a printed circuit board (PCB), however with a considerably higher density of laterally and/or vertically arranged connections. Lateral connections are for example conductive paths, whereas vertical connections may be for example drill holes. These lateral and/or vertical connections are arranged within the substrate and can be used to provide electrical, thermal and/or mechanical connections of housed components or unhoused components (such as bare dies), particularly of IC chips, with a printed circuit board or intermediate printed circuit board. Thus, the term "substrate" also includes "IC substrates". A dielectric part of a substrate may be composed of resin with reinforcing particles (such as reinforcing spheres, in particular glass spheres).

The substrate or interposer may comprise or consist of at least a layer of glass, silicon (Si) and/or a photoimageable or dry-etchable organic material like epoxy-based build-up material (such as epoxy-based build-up film) or polymer compounds (which may or may not include photo- and/or thermosensitive molecules) like polyimide or polybenzoxazole.

In an embodiment, the at least one electrically insulating layer structure comprises at least one of the group consisting of a resin or a polymer, such as epoxy resin, cyanate ester resin, benzocyclobutene resin, bismaleimide- triazine resin, polyphenylene derivate (e.g. based on polyphenylenether, PPE), polyimide (PI), polyamide (PA), liquid crystal polymer (LCP), polytetrafluoroethylene (PTFE) and/or a combination thereof. Reinforcing structures such as webs, fibers, spheres or other kinds of filler particles, for example made of glass (multilayer glass) in order to form a composite, could be used as well. A semi-cured resin in combination with a reinforcing agent, e.g. fibers impregnated with the above-mentioned resins is called prepreg. These prepregs are often named after their properties e.g. FR4 or FR5, which describe their flame retardant properties. Although prepreg particularly FR.4 are usually preferred for rigid PCBs, other materials, in particular epoxy-based build-up materials (such as build-up films) or photoimageable dielectric materials, may be used as well. For high frequency applications, high- frequency materials such as polytetrafluoroethylene, liquid crystal polymer and/or cyanate ester resins, may be preferred. Besides these polymers, low temperature cofired ceramics (LTCC) or other low, very low or ultra-low DK materials may be applied in the component carrier as electrically insulating structures.

In an embodiment, the at least one electrically conductive layer structure comprises at least one of the group consisting of copper, aluminum, nickel, silver, gold, palladium, tungsten, magnesium, carbon, (in particular doped) silicon, titanium, and platinum. Although copper is usually preferred, other materials or coated versions thereof are possible as well, in particular coated with supra-conductive material or conductive polymers, such as graphene or poly(3,4-ethylenedioxythiophene) (PEDOT), respectively.

At least one component may be embedded in and/or surface mounted on the stack. The component and/or the at least one further component can be selected from a group consisting of an electrically non-conductive inlay, an electrically conductive inlay (such as a metal inlay, preferably comprising copper or aluminum), a heat transfer unit (for example a heat pipe), a light guiding element (for example an optical waveguide or a light conductor connection), an electronic component, or combinations thereof. An inlay can be for instance a metal block, with or without an insulating material coating (IMS-inlay), which could be either embedded or surface mounted for the purpose of facilitating heat dissipation. Suitable materials are defined according to their thermal conductivity, which should be at least 2 W/mK.

Such materials are often based, but not limited to metals, metal-oxides and/or ceramics as for instance copper, aluminium oxide (AI2O3) or aluminum nitride (AIN). In order to increase the heat exchange capacity, other geometries with increased surface area are frequently used as well. Furthermore, a component can be an active electronic component (having at least one p-n-junction implemented), a passive electronic component such as a resistor, an inductance, or capacitor, an electronic chip, a storage device (for instance a DRAM or another data memory), a filter, an integrated circuit (such as field- programmable gate array (FPGA), programmable array logic (PAL), generic array logic (GAL) and complex programmable logic devices (CPLDs)), a signal processing component, a power management component (such as a fieldeffect transistor (FET), metal-oxide-semiconductor field-effect transistor (MOSFET), complementary metal-oxide-semiconductor (CMOS), junction field-effect transistor (JFET), or insulated-gate field-effect transistor (IGFET), all based on semiconductor materials such as silicon carbide (SiC), gallium arsenide (GaAs), gallium nitride (GaN), gallium oxide (GazOs), indium gallium arsenide (InGaAs), indium phosphide (InP) and/or any other suitable inorganic compound), an optoelectronic interface element, a light emitting diode, a photocoupler, a voltage converter (for example a DC/DC converter or an AC/DC converter), a cryptographic component, a transmitter and/or receiver, an electromechanical transducer, a sensor, an actuator, a microelectromechanical system (MEMS), a microprocessor, a capacitor, a resistor, an inductance, a battery, a switch, a camera, an antenna, a logic chip, and an energy harvesting unit. However, other components may be embedded in the component carrier. For example, a magnetic element can be used as a component. Such a magnetic element may be a permanent magnetic element (such as a ferromagnetic element, an antiferromagnetic element, a multiferroic element or a ferrimagnetic element, for instance a ferrite core) or may be a paramagnetic element. However, the component may also be a IC substrate, an interposer or a further component carrier, for example in a board-in-board configuration. The component may be surface mounted on the component carrier and/or may be embedded in an interior thereof. Moreover, also other components, in particular those which generate and emit electromagnetic radiation and/or are sensitive with regard to electromagnetic radiation propagating from an environment, may be used as component. In an embodiment, the component carrier obtained from the component carrier structure is a laminate-type component carrier. In such an embodiment, the component carrier is a compound of multiple layer structures which are stacked and connected together by applying a pressing force and/or heat.

After processing interior layer structures of the component carrier, it is possible to cover (in particular by lamination) one or both opposing main surfaces of the processed layer structures symmetrically or asymmetrically with one or more further electrically insulating layer structures and/or electrically conductive layer structures. In other words, a build-up may be continued until a desired number of layers is obtained.

After having completed formation of a stack of electrically insulating layer structures and electrically conductive layer structures, it is possible to proceed with a surface treatment of the obtained layers structures or component carrier.

In particular, an electrically insulating solder resist may be applied to one or both opposing main surfaces of the layer stack or component carrier in terms of surface treatment. For instance, it is possible to form such a solder resist on an entire main surface and to subsequently pattern the layer of solder resist so as to expose one or more electrically conductive surface portions which shall be used for electrically coupling the component carrier to an electronic periphery. The surface portions of the component carrier remaining covered with solder resist may be efficiently protected against oxidation or corrosion, in particular surface portions containing copper.

It is also possible to apply a surface finish selectively to exposed electrically conductive surface portions of the component carrier in terms of surface treatment. Such a surface finish may be an electrically conductive cover material on exposed electrically conductive layer structures (such as pads, conductive tracks, etc., in particular comprising or consisting of copper) on a surface of a component carrier. If such exposed electrically conductive layer structures are left unprotected, then the exposed electrically conductive component carrier material (in particular copper) might oxidize, making the component carrier less reliable. A surface finish may then be formed for instance as an interface between a surface mounted component and the component carrier. The surface finish has the function to protect the exposed electrically conductive layer structures (in particular copper circuitry) and enable a joining process with one or more components, for instance by soldering. Examples for appropriate materials for a surface finish are Organic Solderability Preservative (OSP), Electroless Nickel Immersion Gold (ENIG), Electroless Nickel Immersion Palladium Immersion Gold (ENIPIG), Electroless Nickel Electroless Palladium Immersion Gold (ENEPIG), gold (in particular hard gold), chemical tin (chemical and electroplated), nickel-gold, nickel-palladium, etc. Also nickel-free materials for a surface finish may be used, in particular for high-speed applications. Examples are ISIG (Immersion Silver Immersion Gold), and EPAG (Eletroless Palladium Autocatalytic Gold).

The aspects defined above and further aspects of the invention are apparent from the examples of embodiment to be described hereinafter and are explained with reference to these examples of embodiment.

Brief Description of the Drawings

Figure 1 illustrates a galvanic plating apparatus for galvanically plating a component carrier structure according to an exemplary embodiment of the invention.

Figure 2 illustrates a galvanic plating apparatus for galvanically plating component carrier structures according to another exemplary embodiment of the invention.

Figure 3 illustrates different views of a split anode of a galvanic plating apparatus according to an exemplary embodiment of the invention.

Figure 4 illustrates a design of split anodes of a galvanic plating apparatus according to an exemplary embodiment of the invention.

Figures 5A-5C and Figures 6A-6C illustrate information concerning a thickness distribution of a plated layer of a component carrier structure formed by a galvanic plating apparatus according to an exemplary embodiment of the invention.

Figure 7 and Figure 8 illustrate split anodes of a galvanic plating apparatus according to other exemplary embodiments of the invention.

Detailed Description of the Embodiments

The illustrations in the drawings are schematic. In different drawings, similar or identical elements are provided with the same reference signs.

Before referring to the drawings, exemplary embodiments will be described in further detail, some basic considerations will be summarized based on which exemplary embodiments of the invention have been developed.

Conventionally, copper thickness uniformity of plated component carrier structures (such as PCB panels) may be inadequate. This may lead to defects and consequently to a low yield. In particular for high-density applications (for example with 35 pm/35 pm line trace width and a required copper thickness for example 26 pm), very limited yield has been experienced. During a conventional plating process, it has only been possible to affect the whole panel in terms of plating control.

According to an exemplary embodiment of the invention, a galvanic plating process for depositing metal (preferably copper) on selected electrically conductive surface portions of a component carrier structure (like a panel for forming printed circuit boards) is carried out using an anode (i.e. a plating electrode to which at least temporarily a voltage or current with positive sign is applied) which is spatially and electrically split into a plurality of separate (in particular electrically decoupled) anode parts. Different anode parts may be controlled separately for providing different values of current density to different assigned sections of the component carrier structure to be galvanically plated. By taking this measure, it may be possible to subject the component carrier structure to a spatially dependent current density profile. Subjecting different portions of a component carrier structure in a plating bath to regions of different electric current may lead to a spatially varying efficiency profile of galvanic metal deposition. Hence, in a scenario in which artefacts (for instance of the plating process) may lead to an unintentional spatial variation of the thickness distribution of plated metal on the component carrier structure, a corresponding inverse current density profile may compensate at least partially thickness differences in different regions of the component carrier structure. Hence, the split anode configuration with individually selectable current density values in different spatial regions of the anode may lead to a well-defined or a more homogeneous thickness distribution of metal on a component carrier structure. In particular, a copper thickness distribution on a core layer of a component carrier structure may be rendered more homogeneous. More specifically, a plating architecture may be provided that executes current density adjustment of split anode parts to improve the copper thickness uniformity.

Advantageously, such a plating architecture may be applied in particular to a horizontal plating line to improve copper thickness uniformity. Advantageously, it may be possible to divide the anode current distribution to obtain a uniform copper deposition during plating. Especially, it may be possible to re-adjust the current distribution to improve a previously insufficient copper thickness uniformity. According to an exemplary embodiment of the invention, it may be possible to divide a plating anode into different anode parts to control secondary fields to improve the copper thickness homogeneity by redistributing current density. By appropriately controlling such a divided anode in a horizontal plating line, it may be possible to obtain a refinement of copper thickness output. In particular for manufacturing component carriers with high-density integration (HDI) metallic structures in horizontal plating lines, the formation of a spatially dependent current density profile using anode parts being individually controllable in terms of electric current supply has turned out as highly efficient. Advantageously, exemplary embodiments of the invention may implement a partial current output of separate split anode parts to adjust the copper thickness. In particular, this may allow to address a specific or critical area of the component carrier structure in which a copper thickness may require re-adjustment.

According to exemplary embodiments of the invention, a partial area of a component carrier structure (such as a panel) can be controlled by current density adjustment of individual split anode parts. This may allow to separately adjust a specific area's copper thickness. This may allow to match even demanding fine line trace width requirements. Descriptively speaking, an exemplary embodiment of the invention can divide a component carrier structure into different sections, wherein a split anode approach with a spatially dependent current density profile may allow to affect the copper thickness output of partial areas of the component carrier structure separately. From copper attacking processes or copper adding processes, the copper thickness may be reduced or increased and may have its own characteristics of uniformity due to the structure of equipment. For example, a subtractive process may have three copper thickness reducing processes and three copper thickness increasing processes. Furthermore, it may be possible to create a pattern by final attacking copper thickness. A copper thickness deviation may result from copper thickness decreasing processes. Other deviations may come from copper thickness increasing processes.

According to an exemplary embodiment of the invention, current density adjustment of different anode parts of a horizontal plating line for copper deposition may be executed for improving overall thickness uniformity over a treated component carrier structure (such as a panel).

During a plating process, a copper thickness distribution over a panel may conventionally lack sufficient uniformity, for instance due to influences of preceding processes (which may for example etch away surface copper for cleaning and roughening purposes, however thereby worsening the distribution of copper thickness). By separating an anode into multiple individually controllable anode parts to which different values of electric current may be applied for creating a spatial current density profile, the divided current may allow to build a copper layer with spatially balanced copper thickness. By creating a spatially dependent current density profile over the extension of the component carrier structure immersed in a plating bath using a split anode approach, defects of the readily manufactured component carriers may be reduced and the yield may be improved. To put it shortly, an anode current distribution may be divided spatially to balance deposited copper variation. By taking this measure, it may be possible to enhance a plating process for improving copper thickness distribution, in particular for HDI processes.

Figure 1 illustrates a galvanic plating apparatus 100 for galvanically plating a component carrier structure 102 according to an exemplary embodiment of the invention. The illustrated galvanic plating apparatus 100 may be configured for electroplating of copper on electrically conductive surfaces of the component carrier structure 102. For example, the latter can be a plateshaped panel (for instance having a size of 21.25 x 24.3 inch ² ) for manufacturing printed circuit board (PCB)-type component carriers. The shown galvanic plating apparatus 100 is embodied as a horizontal plating line being particularly appropriate for the below described split anode approach. However, it may also be possible to implement exemplary embodiments in a vertical plating line.

The shown galvanic plating apparatus 100 comprises a plating tank 110 filled with an aqueous plating solution 152 comprising a copper source, such as dissolved copper salt. The aqueous plating solution 152 is an electrolyte. The component carrier structure 102 to be plated with copper may be mounted (for instance alone or together with one or more other component carrier structures, not shown) on a support structure (not shown), such as a galvanic clamp. When mounted on such a support structure, the component carrier structure 102 may be conveyed along the galvanic plating apparatus 100 in a horizontal direction.

Moreover, the galvanic plating apparatus 100 may comprise a current source 116 for providing an electric current during the copper plating process. In the shown embodiment, the electric current provided by the current source 116 may be a direct current (DC). In another embodiment, it is also possible to provide a pulsed current. A minus pole of the current source 116 may be electrically connected with an electrically conductive structure (for example a seed layer) of the component carrier structure 102, either directly or by an electrically conductive support structure. By taking this measure, the component carrier structure 102 may act as cathode 114 during the plating process. A plus pole of the current source 116 may be electrically connected with an anode 104 which is immersed as well in the plating solution 152. As shown, the anode 104 is split into a plurality of separate anode parts 106. Different anode parts 106 may have different partial areas or may have the same partial areas. Each of the separate anode parts 106 is configured for providing a separate current density to a spatially assigned (for example directly facing) section 120 of the component carrier structure 102. More specifically, different current densities may be applied to different anode parts 106. This may be accomplished by a control unit 108 providing each individual anode part 106 with an individually selectable current density from current source 116. By individually applying separately adjustable current density values to each respective one of the anode parts 106, it may be possible to create a spatially dependent current density profile over an extension of the component carrier structure 102 during the galvanic plating process. Just as an example, a current density applied to anode part 106' (for instance located on the left-hand side of Figure 1) may be different from another current density applied to anode part 106" (for instance located on the right-hand side of Figure 1). In contrast to this, a current provided to the cathode 114 may be the same for all sections 120 of the component carrier structure 102.

For example, a potential difference may be applied between the anode 104 and the cathode 114. An obtained current may be the result of an equalizing reaction of the differently applied potential. When a common potential or voltage is applied at the cathode 114, different current densities may result from different voltages applied at the anode parts 106' and 106". A difference in potential between cathode 114 and anode part 106' results in a first current density, whereas a difference in potential between cathode 114 and anode part 106" results in another second current density.

As a consequence, a current flow in the electrolyte 152 in a region 154 between anode part 106' and an assigned section 120' of the component carrier structure 102 may be different from a current flow in the electrolyte 152 in a region 156 between anode part 106" and an assigned section 120" of the component carrier structure 102. As a result, the efficiency of the galvanic copper deposition on section 120' may be adjusted to be different from the efficiency of the galvanic copper deposition on section 120". In a scenario in which, due to undesired artefacts, the intrinsic efficiency of galvanic deposition of copper in sections 120' and 120" is different (for instance as a consequence of different integration densities in said sections 120', 120") which may lead to unwanted different copper thicknesses in sections 120', 120", homogeneity of copper thickness in regions 120' and 120" can be improved by appropriately adjusting the current densities in anode parts 106' and 106" for partially or entirely compensating this artifact.

For this purpose, the control unit 108 can be configured for separately controlling the current density applied to each of the anode parts 106 for enhancing deposited metal thickness homogeneity over an entire extension of the component carrier structure 102. Hence, the control unit 108 may be configured for controlling the current density applied to each of the anode parts 106 to thereby form a metal pattern on the component carrier structure 102 with substantially homogeneous thickness. In particular, it may be possible to control the split anode parts 106 of the anode 104 for providing a more homogeneous thickness distribution of plated metal on the component carrier structure 102 compared with a spatially independent current density over the extension of the component carrier structure 102. More specifically, the control unit 108 may be configured for controlling the anode 104 for adjusting the spatially dependent current density profile so that different sections 120 of the component carrier structure 102 are individually galvanically plateable with different plating parameters, in particular with different plating efficiency or metal deposition rate.

Advantageously, it may also be possible that the control unit 108 is configured for dynamically controlling the current density applied to each of the anode parts 106 to vary over time. Thus, the spatial current density distribution over the anode 104 may be changed over time. For instance when determining pronounced copper thickness inhomogeneity over the extension of the component carrier structure 102, the current distribution may be modified for at least partially balancing out said inhomogeneity. For example, said determination may be carried out by visual inspection by an operator and/or by a machine-based measurement (for instance by an optical camera and/or by measuring electric conductivity of deposited metal in different regions 120). By adjusting or changing the current density distribution not only spatially but also over time, the control of the plating process may be further refined. When dynamically controlling the current density values of the individual anode parts 106, the control unit 108 may be configured for determining information indicative of a metal distribution over the component carrier structure 102 to be galvanically plated. The control unit 108 may then be configured for adjusting or re-adjusting the spatially dependent current density profile over the extension of the component carrier structure 102 to decrease a thickness variation of the metal distribution over the entire component carrier structure 102. Determining said information may be accomplished by an operator and/or by a machine-based measurement, as described above. If deficiencies appear from a result of said determination, the control unit 108 may take countermeasures for reducing or even eliminating said deficiencies. Said countermeasures may include a corresponding adjustment of the current density profile between anode 104 and component carrier structure 102. Said adjustment may be made by correspondingly adjusting or re-adjusting current supply to the individual anode parts 106. In an embodiment, the control unit 108 may be configured for controlling the anode parts 106 and additionally at least one subtractive process (such as an etching or grinding process) for removing metal from the component carrier structure 102 for controlling metal distribution (in particular metal thickness) on the component carrier structure 102. Additionally or alternatively, the control unit 108 may be configured for controlling the anode parts 106 and at least one additive process (for example sputtering) for applying metal to the component carrier structure 102. The mentioned subtractive and/or additive process(es) may be carried out prior to and/or after the illustrated galvanic plating process. By considering also additive metal supply and/or subtractive metal removal processes in combination with the adjustment of the galvanic plating process, it may be possible to further enhance homogeneity of distribution of metal on the component carrier structure 102.

In a preferred embodiment, the control unit 108 is configured for controlling the current density applied to each of the anode parts 106 to thereby form a metal pattern on the component carrier structure 102 in accordance with a predefined target specification, in particular in compliance with tolerances allowed by such a predefined target specification. Such a predefined target specification may define the properties of the component carriers (for instance printed circuit boards) manufactured on the basis of the processed component carrier structure 102. For instance, such a target specification may define horizontal and/or vertical metallic wiring structures and/or horizontal and/or vertical metallic interconnection structures of the component carrier structure 102 to be formed by the galvanic plating apparatus 100. For example, the target specification may also indicate a desired metal thickness or metal thickness range of the mentioned metallic structures. The control unit 108 may access such a target specification, for instance in the form of a data set or a design file, from a database 160. Database 160 may for instance be embodied as a mass storage device, such as a hard disk. An adjustment of the plating process may be accomplished by the control unit 108, in particular in terms of controlling the split anode parts 106, to achieve compliance with the predefined target specification. For instance when determining (by visual inspection and/or by carrying out a machine-based measurement, as mentioned above) that a presently plated metal structure on the component carrier structure 102 is out of specification on the entire component carrier structure 102 or at one or more individual sections 120, the spatially dependent current density distribution of the split anode parts 106 may be readjusted to comply with the specification. This may include spatially dependent metal thickening (for instance by increasing current density) or metal thinning (for instance by temporarily applying a reverse current for triggering galvanic metal removal) in a spatially defined way.

Additionally or alternatively to a provision of control data by database 160, control unit 108 (which may be, for example, a processor, a plurality of processors or a part of a processor) may receive data and/or instructions from an input/output unit 162. By input/output unit 162, a user may input data and/or instructions to the galvanic plating apparatus 100. It is also possible that the input/output unit 162 presents results of operation parameters to the user, for instance on a display.

Figure 2 illustrates a galvanic plating apparatus 100 for galvanically plating two component carrier structures 102 according to another exemplary embodiment of the invention.

The galvanic plating apparatus 100 according to Figure 2 comprises a plurality of galvanic plating tanks 110 through which the component carrier structures 102 are conveyed sequentially during galvanically plating. As shown, each of the galvanic plating tanks 110 comprises an anode 104 split into a plurality of separate anode parts 106. Splitting of each anode 104 may be accomplished along a conveying direction 112 and/or perpendicular to conveying direction 112, i.e. may be split in horizontal and/or vertical direction. The component carrier structures 102 are conveyed one after the other along the galvanic plating tanks 110. For conveying the component carrier structures 102, a conveyor mechanism 118 for supporting and conveying the component carrier structures 102 along the serially arranged anode parts 106 of the anodes 104 is provided. As shown, the conveyor mechanism 118 conveys the component carrier structures 102 in a horizontal orientation along the anode parts 106 of the anodes 104, more specifically along a direction parallel with respect to the orientation of the anode parts 106. The component carrier structures 102 may be supplied to the galvanic plating tanks 110 at a loader section 166. After galvanic plating in the serial galvanic plating tanks 110, the component carrier structures 102 may be removed from the galvanic plating apparatus 100 at an unloader section 167.

When being supplied to the two serially arranged galvanic plating tanks 110, the component carrier structures 102 may have a defective region 164 in which a local copper thickness is too large or too small (for instance as a result of defective previous additive and/or subtractive treatment of the component carrier structures 102). Such an inadequate copper thickness in a defective region 164 of a respective component carrier structure 102 may be compensated by selecting the current density distribution of the anode parts 106 so that the defective region 164 can be selectively overplated or underplated. This may be done in such a way that non-defective plated component carrier structures 102 can be obtained after having passed the galvanic plating tanks 110. In the shown embodiment, in particular the uppermost anode parts 106 can be subjected to a modified current density, since these uppermost anode parts 106 will have a pronounced impact on the plating characteristics of the defective regions 164.

Each of the copper plating tanks 110 may have its own chevron structure of the respective anode 104. Current density adjustment of the individual anode parts 106 allows a fine-tuning of the copper thickness distribution on the component carrier structures 102.

Figure 3 illustrates different views of a split anode 104 of a galvanic plating apparatus 100 according to an exemplary embodiment of the invention. With the illustrated configuration, copper thickness distribution of galvanically plated component carrier structures 102 can be significantly improved or homogenized. In the shown embodiments, an anode structure comprising a mesh is shown.

Highly advantageously, there may be a dynamic continuous adjustment of the current density assigned to the individual anode parts 106 due to the illustrated structuring of a horizontal plating line. In the shown embodiment, a respective anode 104 is split into four anode parts 106. A chevron structure may allow for an efficient dynamic adjustment. Figure 4 illustrates a design of split anodes 104 of a galvanic plating apparatus 100 according to an exemplary embodiment of the invention. According to Figure 4, the anode parts 106 are chevron-shaped and have zig zag edges 168. However, the illustrated anode 104 split into the anode parts 106 has an overall rectangular shape or outline, as indicated by exterior edges 170.

The illustrated chevron design of the anode parts 106 of the shown serially arranged split anodes 104 efficiently promotes homogeneous metal deposition when being appropriately powered by individual current densities. The shown chevron shape may thus reliably prevent a pronounced copper thickness variation over the surface of a panel-type component carrier structure 102. The zig zag edges 168 are formed by an alternating sequence of inwardly tapered edge portions 174 and outwardly tapered edge portions 176. For instance, an inwardly or outwardly tapering angle [3 of an inwardly tapered edge portions 174 or an outwardly tapered edge portions 176 may be less than 20°, in relation to a linear edge 179 extending in conveying direction 112.

By a graphic simulation, it may be possible to go back to a real structure of a copper tank, showing the simulation of the anode effective area. The current density adjustment factor can be calculated by the current value divided by an area of anode parts 106.

Figures 5A, 5B ,5C and Figures 6A, 6B, 6C illustrate information concerning a thickness distribution of a plated layer of a component carrier structure 102 formed by a galvanic plating apparatus 100 according to an exemplary embodiment of the invention.

Individual sections 120 of the illustrated component carrier structure 102 may show different values of copper thickness, in particular regions 182 with too large copper thickness and regions 184 with too small copper thickness. Figures 5A-5C and Figures 6A-6C illustrate the characteristics on the top side 188 and on the bottom side 186 of the component carrier structure 102. Data concerning columns of sections 120 are plotted with reference signs 190, and data concerning rows of sections 120 are plotted with reference signs 192 (both for the top side 188, see reference sign 194, and for the bottom side 186, see reference sign 196). Summary information is plotted in a section 198.

Figures 6A-6C shows an improvement over Figures 5A-5C in terms of a reduction of a systematic deviation of the copper thickness, in particular on the top side. Such an improvement may be achieved by an appropriate readjustment of the current density on the anode parts 106 of the split anode 104.

After optimization the plating process, the front side the component carrier structure 102 shows positive results what concerns copper thickness distribution. Optimization may include a dynamic continuous adjustment of a current density applied to a split anode 104 based on equipment characteristics. In particular, it may be possible to divide an anode 104 into a plurality of (for example four) anode parts 106, preferably with chevron structure. This may efficiently impact sub-panel areas what concerns copper thickness uniformity. Defects of component carrier structures 102 after plating may be efficiently suppressed.

Figure 7 and Figure 8 illustrate split anodes 104 of a galvanic plating apparatus 100 according to other exemplary embodiments of the invention. As in Figure 2, the illustrated anodes 104 of Figure 7 and Figure 8 are split into a plurality of separate anode parts 106, but in a different way than in Figure 2. In Figure 7 and Figure 8, all interfaces between adjacent anode parts 106 are sloped downwardly from left to right. As shown in the various figures, many different geometries of separate anode parts 106 are possible.

It should be noted that the term "comprising" does not exclude other elements or steps and the "a" or "an" does not exclude a plurality. Also elements described in association with different embodiments may be combined.

It should also be noted that reference signs in the claims shall not be construed as limiting the scope of the claims.

Implementation of the invention is not limited to the preferred embodiments shown in the figures and described above. Instead, a multiplicity of variants are possible which use the solutions shown and the principle according to the invention even in the case of fundamentally different embodiments.