MANUFACTURE OF DEVICES HAVING ORGANIC MATERIALS

FIELD

[0001] Embodiments of the present disclosure relate to a method for cleaning a vacuum chamber, an apparatus for vacuum processing of a substrate, and a system for the manufacture of devices having organic materials. Embodiments of the present disclosure particularly relate to methods, apparatuses, and systems used in the manufacture of organic light-emitting diode (OLED) devices.

BACKGROUND

[0002] Techniques for layer deposition on a substrate include, for example, thermal evaporation, physical vapor deposition (PVD), and chemical vapor deposition (CVD). Coated substrates may be used in several applications and in several technical fields. For instance, coated substrates may be used in the field of organic light emitting diode (OLED) devices. OLEDs can be used in the manufacture of television screens, computer monitors, mobile phones, other hand-held devices, and the like for displaying information. An OLED device, such as an OLED display, may include one or more layers of an organic material situated between two electrodes that are all deposited on a substrate.

[0003] OLED devices can include a stack of several organic materials, which are evaporated in a vacuum chamber of a processing apparatus for example. The organic materials are deposited on a substrate in a subsequent manner through shadow masks using evaporation sources. The vacuum conditions inside the vacuum chamber are crucial for the quality of the deposited material layers and the OLED devices manufactured using these material layers. [0004] Therefore, there is a need for a method, apparatus and system that can improve vacuum conditions inside a vacuum chamber. The present disclosure particularly aims at improving vacuum conditions such that a quality of layers of an organic material deposited on a substrate can be improved.

SUMMARY [0005] In light of the above, a method for cleaning a vacuum chamber, an apparatus for vacuum processing of a substrate, and a system for the manufacture of devices having organic materials are provided. Further aspects, benefits, and features of the present disclosure are apparent from the claims, the description, and the accompanying drawings.

[0006] According to an aspect of the present disclosure, a method for cleaning a vacuum chamber is provided. The method includes reducing a pressure in the vacuum chamber to evaporate at least a part of a solvent contained in the vacuum chamber.

[0007] According to another aspect of the present disclosure, an apparatus for vacuum processing of a substrate is provided. The apparatus includes a vacuum chamber, one or more solvent containers in the vacuum chamber, and a controller configured to reduce a pressure in the vacuum chamber to evaporate at least a part of a solvent contained in the one or more solvent containers.

[0008] According to a further aspect of the present disclosure, a system for the manufacture of devices having organic materials is provided. The system includes the apparatus for vacuum processing of a substrate according to the embodiments described herein and a transport arrangement configured for contactless transportation of at least one of a substrate carrier and a mask carrier in the vacuum chamber.

[0009] Embodiments are also directed at apparatuses for carrying out the disclosed methods and include apparatus parts for performing each described method aspect. These method aspects may be performed by way of hardware components, a computer programmed by appropriate software, by any combination of the two or in any other manner. Furthermore, embodiments according to the disclosure are also directed at methods for operating the described apparatus. The methods for operating the described apparatus include method aspects for carrying out every function of the apparatus. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments. The accompanying drawings relate to embodiments of the disclosure and are described in the following:

FIG. 1 shows a flowchart of a method for cleaning a vacuum chamber according to embodiments described herein;

FIG. 2 shows a schematic view of an apparatus for vacuum processing of a substrate according to embodiments described herein;

FIG. 3 shows a schematic view of a system for the manufacture of devices having organic materials according to embodiments described herein; and FIG. 4 shows a schematic view of a system for the manufacture of devices having organic materials according to further embodiments described herein.

DETAILED DESCRIPTION OF EMBODIMENTS [0011] Reference will now be made in detail to the various embodiments of the disclosure, one or more examples of which are illustrated in the figures. Within the following description of the drawings, the same reference numbers refer to same components. Generally, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation of the disclosure and is not meant as a limitation of the disclosure. Further, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the description includes such modifications and variations. [0012] The vacuum conditions inside a vacuum chamber can be crucial for a quality of material layers deposited on a substrate. The present disclosure provides a cleaning procedure in which a solvent is placed inside the vacuum chamber. The pressure inside the vacuum chamber is reduced such that at least a part of the solvent evaporates. Contaminants, such as organic contaminants (e.g., plasticizers and/or other hydrocarbons) can be removed from the vacuum chamber and/or from equipment in the vacuum chamber. In particular, during pumping (i.e., reducing the pressure) the solvent starts to evaporate and a fraction condensates at the cold wall(s) of the vacuum chamber and/or at the equipment. The solvent initiates for example reactions with the contaminants, which can lead to the formation of volatile compounds. Vacuum conditions inside the so-cleaned vacuum chamber can be improved and the quality of the layers of an organic material deposited on a substrate can be improved.

[0013] FIG. 1 shows a flowchart of a method 100 for cleaning a vacuum chamber according to embodiments described herein. The vacuum chamber can be a processing vacuum chamber used for deposition of an organic material on a substrate.

[0014] The method 100 includes, in block 110, reducing a (gas) pressure in the vacuum chamber to evaporate at least a part of a solvent contained in the vacuum chamber. In block 120, at least a fraction of the evaporated solvent condensates on one or more (inner) chamber walls of the vacuum chamber and/or equipment inside the vacuum chamber. Contaminants, such as organic contaminants, can be split up into two or more components or parts. The two or more components or parts can have a higher vapor pressure than the original contaminant(s). The two or more components or parts having the higher vapor pressure can be more easily removed or pumped out of the vacuum chamber. A highly efficient cleaning process can be provided for removing contaminants from the vacuum chamber and/or equipment provided therein.

[0015] According to some embodiments, the solvent is contained in one or more solvent containers inside the vacuum chamber. The solvent container can have one or more openings such that the evaporated solvent can be diffused or ejected into the vacuum chamber. In some implementations, an amount of the solvent contained in the vacuum chamber, and particularly in the one or more solvent containers, is 0.5 liter or less per unit volume of the vacuum chamber, specifically 0.3 liter or less per unit volume, and more specifically 0.1 liter or less per unit volume. As an example, the amount of the solvent contained in the vacuum chamber can be about 0.1 liter per unit volume. The unit volume can be m . The part of the solvent that evaporates can be 10% or less, specifically 25% or less, specifically 50%> or less, and more specifically 75% or less of the amount of the solvent contained in the one or more solvent containers. In some embodiments, essentially the entire solvent contained in the one or more solvent containers can be evaporated during the cleaning process.

[0016] In some implementations, the (gas) pressure in the vacuum chamber can be reduced such that at least the part of the solvent evaporates and condenses on the vacuum chamber (e.g., on the inner chamber walls of the vacuum chamber) and/or equipment inside the vacuum chamber. The equipment can include, but is not limited to, drives, substrate and/or carrier transportations devices, material deposition equipment (e.g., evaporation sources), moveable devices (e.g., valves), and the like.

[0017] According to some embodiments, which can be combined with other embodiments described herein, the pressure in the vacuum chamber is reduced to 10 ^"5 mbar or less, specifically 10 - ^" 7 mbar or less, and more specifically 10 - ^" 9 mbar or less. As an example, the cleaning process can be considered completed when the pressure has reached 10 ^"5 mbar or less, specifically, 10 ^"7 mbar or less, and more specifically 10 ^"9 mbar or less. The pressure can be reduced to establish a technical vacuum. One or more vacuum pumps, such as turbo pumps and/or cryo-pumps, connected to the vacuum chamber for generation of the technical vacuum inside the vacuum chamber can be provided.

[0018] According to some embodiments, which can be combined with other embodiments described herein, the method can include a controlling and/or adjusting of a temperature of portions of the vacuum chamber, e.g., of one or more walls of the vacuum chamber, during the reduction of the pressure. As an example, the temperature of the vacuum chamber can be controlled such that reactions of the evaporated and condensed solvent with the contaminants are promoted. The efficiency of the cleaning process can be enhanced.

[0019] The one or more contaminants can originate from internal sources and/or external sources, such as polymers and fluids. Internal sources may include, but are not limited to, cables, O-rings, bumpers, ferrofluidic sealings, pneumatic cylinder shutters, and the like. External sources may include, but are not limited to, polymers brought into the vacuum chamber during installation and/or maintenance, pump oils (back diffusion), impurities of cleaning solvents (e.g. IPA 99.7%), impurities due to venting air, vacuum greases, and the like.

[0020] The solvent can be selected based on one or more contaminants to be removed by the solvent. In particular, the solvent can be selected based on one or more of the contaminants most found in the vacuum chamber. According to some embodiments, which can be combined with other embodiments described herein, the solvent is a liquid solvent. In some implementations, the solvent is selected from the group including ethanol, acetone, propanol, isopropanol, water, N-Methyl-2-pyrrolidon, chloroform, and any combination thereof. In some implementations, two or more solvents can be used in the cleaning procedure. As an example, the two or more solvents can be mixed in one solvent container or can be provided separately in respective solvent containers. [0021] Cleaning with alcohols and/or water can lead to dissociation and follow up products over different reaction channels. In particular, alcohols and/or water can hydrolyze Esther. Depending on the reaction conditions (e.g. solvent, temperature, concentrations), other follow up reactions can take place. In some implementations, the metallic surface of the inner chamber walls can have a catalytic effect. [0022] According to some embodiments, which can be combined with other embodiments descried herein, the method 100, and particularly the reduction of the pressure in the vacuum chamber for evaporating at least a part of a solvent contained in the vacuum chamber is repeatedly performed. For example, the reduction of the pressure can be performed two, three, four, or even more times. Between two pressure reduction operations, the pressure in the vacuum chamber can be increased e.g. by introducing a gas such as nitrogen in the vacuum chamber to avoid new contamination.

[0023] According to some embodiments, which can be combined with other embodiments descried herein, the method 100 includes one or more further cleaning procedures before and/or after the reduction of the pressure in the vacuum chamber to evaporate the solvent. The one or more further cleaning procedures can include, for example, wet chemical cleaning.

[0024] In some implementations, the method 100 is conducted during a pump down for establishing vacuum conditions, i.e., the technical vacuum, for a layer deposition process. In other words, the method 100 can be included in an existing procedure without being implemented as a separate pressure reduction process. A downtime of a manufacturing system for cleaning and/or maintenance can be reduced. However, the present disclosure is not limited thereto and, in other implementations, the method 100 is implemented as a separate pressure reduction process. [0025] FIG. 2 shows a schematic view of an apparatus 200 for vacuum processing of a substrate according to embodiments described herein.

[0026] The apparatus 200 includes a vacuum chamber 210, one or more solvent containers 220 in the vacuum chamber 210, and a controller 230 configured to reduce a pressure in the vacuum chamber 210 to evaporate at least a part of a solvent 201 contained in the solvent container 220. The controller 230 can be configured to implement the method for cleaning a vacuum chamber according to the embodiments described herein. The one or more solvent containers 220 can be provided removably or fixed in the vacuum chamber 210.

[0027] One or more vacuum pumps 240, such as turbo pumps and/or cryo-pumps, can be connected to the vacuum chamber 210, e.g. via one or more tubes 242 such as bellow tubes for generation of a technical vacuum inside the vacuum chamber 210. The controller 230 can be configured to control the one or more vacuum pumps 240 to reduce the pressure in the vacuum chamber 210.

[0028] The term "vacuum" as used throughout the present disclosure can be understood in the sense of a technical vacuum having a vacuum pressure of less than, for example, 10 mbar. The pressure in the vacuum chamber may be between 10 - ^" 5 mbar and about 10 - ^" 8 mbar, specifically between 10 ^"5 mbar and 10 ^"7 mbar, and more specifically between about 10 ^"6 mbar and about 10 ^"7 mbar. [0029] According to some embodiments, which can be combined with other embodiments described herein, the solvent container 220 has one or more openings for passage of the evaporated solvent into the vacuum chamber 210. The evaporated solvent can be diffused into the volume 212 of the vacuum chamber 210. In some embodiments, essentially the entire solvent contained in the solvent container 220 is evaporated and released into the volume 212.

[0030] The volume of the vacuum chamber into which the solvent is evaporated can be defined as a volume enclosed at least by the inner chamber walls. According to some embodiments, which can be combined with other embodiments described herein, the volume of the vacuum chamber to be cleaned by the solvent contained in the one or more solvent containers can be 40m 3 or less, specifically 30m 3 or less, and more specifically 20m or less. As an example, the volume of the vacuum chamber can be in a range between 5m 3 and 40m 3 , specifically in a range between 15m 3 and 25m 3 , and more specifically can be about 20m . [0031] In some implementations, two or more solvent containers can be provided in the vacuum chamber 210. The two or more solvent containers can be configured for containing different solvents and/or different amounts of solvent(s). As an example, different solvents can be used to remove different contaminants. In particular the two or more solvents can be selected based on the contaminants that are to be dissolved by the solvent. The efficiency of the cleaning process can be further improved.

[0032] According to some embodiments, the apparatus 200 can be included in a system for the manufacture of devices having organic materials therein, such as OLED devices. For example, the apparatus 200 can include one or more material deposition sources, such as evaporation sources, in the vacuum chamber configured for deposition of one or more organic materials on the substrate. Exemplary systems for the manufacture of devices having organic materials therein are explained with respect to FIGs. 3 and 4.

[0033] FIG. 3 shows a schematic view of a system 300 for the manufacture of devices having organic materials according to embodiments described herein. The system 300, which can also be referred to as "vacuum system", can be configured for depositing one or more layers, e.g. of an organic material, on the substrate 10. The system 300 can be cleaned using the method and apparatus according to the embodiments described herein.

[0034] The system 300 includes the apparatus for vacuum processing of a substrate according to the embodiments described herein and a transport arrangement 310 configured for contactless transportation of at least one of a substrate carrier 320 and a mask carrier in the vacuum chamber 302.

[0035] In some implementations, the system 300 includes one or more material deposition sources 380, such as one or more evaporation sources, in the vacuum chamber 302. The substrate carrier 320 can be configured to hold the substrate 10 and optionally a mask 20 during a vacuum deposition process. The system 300 can be configured for evaporation of e.g. an organic material for the manufacture of OLED devices. In another example, the system 300 can be configured for CVD or PVD, such as sputter deposition.

[0036] In some implementations, the one or more material deposition sources 380 can be evaporation sources, particularly evaporation sources for depositing one or more organic materials on a substrate to form a layer of an OLED device. The substrate carrier 320 for supporting the substrate 10 e.g. during a layer deposition process can be transported into and through the vacuum chamber 302, and in particular through a deposition area, along a transportation path, such as a linear transportation path.

[0037] The material can be emitted from the one or more material deposition sources 380 in an emission direction towards the deposition area in which the substrate 10 to be coated is located. For instance, the one or more material deposition sources 380 may provide a line source with a plurality of openings and/or nozzles which are arranged in at least one line along the length of the one or more material deposition sources 380. The material can be ejected through the plurality of openings and/or nozzles. [0038] As indicated in FIG. 3, further chambers can be provided adjacent to the vacuum chamber 302. The vacuum chamber 302 can be separated from adjacent chambers by a valve having a valve housing 304 and a valve unit 306. After the substrate carrier 320 with the substrate 10 and an optional mask thereon is inserted into the vacuum chamber 302 as indicated by the arrow, the valve unit 306 can be closed. The atmosphere in the vacuum chamber 302 can be individually controlled by generating the technical vacuum, for example with vacuum pumps connected to the vacuum chamber 302. The vacuum pumps can be used to perform the cleaning procedure according to the embodiments described herein. [0039] According to some embodiments, the substrate carrier 320 and the substrate 10 are static or dynamic during deposition of the deposition material. According to some embodiments described herein, a dynamic deposition process can be provided, e.g., for the manufacture of OLED devices.

[0040] In some implementations, the system 300 can include one or more transportation paths extending through the vacuum chamber 302. The carrier can be configured for transportation along the one or more transportation paths, for example, past the one or more material deposition sources 380. Although one transportation path is exemplarily indicated by the arrow, it is to be understood that the present disclosure is not limited thereto and that two or more transportation paths can be provided. As an example, at least two transportation paths can be arranged substantially parallel to each other for transportation of respective carriers. The one or more material deposition sources 380 can be arranged between the two transportation paths.

[0041] The transport arrangement 310 can be configured for contactless levitation and contactless transportation of the substrate carrier 320 in the vacuum chamber, e.g., along the one or more transportation paths in a transport direction. The contactless levitation and/or transportation of the substrate carrier 320 is beneficial in that no particles are generated during transportation, for example due to mechanical contact with guide rails. An improved purity and uniformity of the layers deposited on the substrate 10 can be provided, since particle generation is minimized when using the contactless levitation and/or transportation.

[0042] FIG. 4 shows a schematic view of a system 400 for the manufacture of devices having organic materials according to further embodiments described herein. The system 400 can be cleaned using the method and apparatus according to the embodiments described herein. [0043] The system 400 includes two or more processing regions and a transport arrangement 460 configured for sequentially transporting a carrier 401 for supporting a substrate 10 and optionally a mask to the two or more processing regions. For example, the transport arrangement 460 can be configured for transporting the carrier 401 along a transport direction 2 through the two or more processing regions for substrate processing. In other words, the same carrier is used for transportation of the substrate 10 through multiple processing regions. In particular, the substrate 10 is not removed from the carrier 401 between substrate processing in a processing region and substrate processing in a subsequent processing region, i.e., the substrate stays on the same carrier for two or more substrate processing procedures .

[0044] As exemplarily illustrated in FIG. 4, the two or more processing regions can include a first deposition region 408 and a second deposition region 412. Optionally, a transfer region 410 can be provided between the first deposition region 408 and the second deposition region 412. The plurality of regions, such as the two or more processing regions and the transfer region, can be provided in one vacuum chamber. Alternatively, the plurality of regions can be provided in different vacuum chambers connected to each other. As an example, each vacuum chamber can provide one region. Specifically, a first vacuum chamber can provide the first deposition region 408, a second vacuum chamber can provide the transfer region 410, and a third vacuum chamber can provide the second deposition region 412. In some implementations, the first vacuum chamber and the third vacuum chamber can be referred to as "deposition chambers". The second vacuum chamber can be referred to as "processing chamber". Further vacuum chambers or regions can be provided adjacent to the regions shown in the example of FIG. 4.

[0045] The vacuum chambers or regions can be separated from adjacent regions by a valve having a valve housing 404 and a valve unit 405. After the carrier 401 with the substrate 10 thereon is inserted into a region, such as the second deposition region 412, the valve unit 405 can be closed. The atmosphere in the regions can be individually controlled by generating the technical vacuum, for example, with vacuum pumps connected to the regions and/or by inserting one or more process gases, for example, in the first deposition region 408 and/or the second deposition region 412. A transportation path, such as a linear transportation path, can be provided in order to transport the carrier 401, having the substrate 10 thereon, into, through and out of the regions. The transportation path can extend at least in part through the two or more processing regions, such as the first deposition region 408 and the second deposition region 412, and optionally through the transfer region 410. [0046] The system 400 can include the transfer region 410. In some embodiments, the transfer region 410 can be omitted. The transfer region 410 can be provided by a rotation module, a transit module, or a combination thereof. FIG. 4 illustrates a combination of a rotation module and a transit module. In the rotation module, the track arrangement and the carrier(s) arranged thereon can be rotated around a rotational axis, such as a vertical rotation axis. As an example, the carrier(s) can be transferred from the left side of the system 400 to the right side of the system 400, or vice versa. The transit module can include crossing tracks such that carrier(s) can be transferred through the transit module in different directions, e.g., directions perpendicular to each other.

[0047] Within the deposition regions, such as the first deposition region 408 and the second deposition region 412, one or more deposition sources can be provided. As an example, a first deposition sources 430 can be provided in the first deposition region 408. A second deposition source 450 can be provided in the second deposition region 412. The one or more deposition sources can be evaporation sources configured for deposition of one or more organic layers on the substrate 10 to form an organic layer stack for an OLED device.

[0048] The systems described herein can be utilized for evaporation on large area substrates, e.g., for OLED display manufacturing. Specifically, the substrates for which the systems according to embodiments described herein are provided, are large area substrates. For instance, a large area substrate or carrier can be GEN 4.5, which corresponds to a surface area of about 0.67 m ² (0.73 x 0.92m), GEN 5, which corresponds to a surface area of about 1.4 m ² (1.1 m x 1.3 m), GEN 7.5, which corresponds to a surface area of about 4.29 m ² (1.95 m x 2.2 m), GEN 8.5, which corresponds to a surface area of about 5.7m ² (2.2 m x 2.5 m), or even GEN 10, which corresponds to a surface area of about 8.7 m ² (2.85 m x 3.05 m). Even larger generations such as GEN 11 and GEN 12 and corresponding surface areas can similarly be implemented. Half sizes of the GEN generations may also be provided in OLED display manufacturing. [0049] The vacuum conditions inside a vacuum chamber can be crucial for a quality of material layers deposited on a substrate. The present disclosure provides a cleaning procedure in which a solvent is placed inside the vacuum chamber. The pressure inside the vacuum chamber is reduced such that at least a part of the solvent evaporates. Contaminants, such as organic contaminants (e.g., plasticizers and/or other hydrocarbons) can be removed from the vacuum chamber and/or from equipment in the vacuum chamber. In particular, during pumping the solvent starts to evaporate and a fraction condensates at the cold wall(s) of the vacuum chamber and/or at the equipment. The solvent can initiate reactions with the contaminants, which can lead to the formation of volatile compounds. Vacuum conditions inside the cleaned vacuum chamber can be improved and the quality of the layers of an organic material deposited on a substrate can be improved.

[0050] While the foregoing is directed to embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.