METHOD FOR MANUFACTURING MICRO CHIP MODULES

Technical Field

[0001] The present invention relates to a micro chip module comprising at least a patch antenna together with one or more radio transceivers and other electronic circuitry. The inventions also relates to a sheet of micro chip modules where each micro chip module comprises at least a patch antenna, at least one radio transceiver module and at least one power regulating circuitry, moreover the invention relates to a method for manufacturing one or more micro chip modules comprising at least a patch antenna.

Background Art

[0002] The widespread use of handheld and portable devices such as digital

cameras, cell phones, eBook readers, tablet computers, net book computers, media players, GPS receivers, and video game consoles has lead to an explosive rate of development with respect to wireless communication. Within the mobile telephone industry the development of smart phones has lead to integration of wireless communication means such as Bluetooth and WLAN transceivers. However many telephones and many other portable devices lacks such facilities as wireless communication capabilities moreover from a user service point of view it may be advantageous to address certain services through a separate WLAN module than the one inherit in the portable device.

[0003] From US 2008/01 1 1756 A1 it is disclosed a memory card including an

antenna however no transceiver or receiver.

[0004] It is also known to include antennas and RF-interfaces onto IC-cards, one example is disclosed in EP 2 219 139 A1.

[0005] Thus, it is an object according to the present invention to provide means

making it possible to communicate wirelessly, preferably following WLAN standards, with portable devices that do not include such wireless

communication capabilities, or to provide alternative/additional

communications means to portable devices that already includes such means. Disclosure of Invention

[0006] An object of the invention is to provide means which makes it possible to communicate wirelessly, preferably following WLAN standards. This object is achieved according to the invention by a "plug-in" micro chip module which includes antennas and transceivers configured to comply with WLAN standards.

[0007] More precisely, according to the invention the above objects are achieved with a micro chip module comprising at least a patch antenna, at least one radio transceiver module and at least one power regulating circuitry. The module has a form factor substantially similar to a SIM card or a memory card for portable devices. The module at least comprises:

a) a first upper layer,

b) a patch of the patch antenna adjacent to the first upper layer

or printed on the first upper layer;

c) a second lower and opposite multilayer PCB being essentially

congruent with the first layer, where the second multilayer PCB at least comprises; the at least one radio transceiver module, and a power regulating circuitry facing upwards, and where at least one of the conductive layers of the second multilayer PCB is utilized as a ground layer to the patch

antenna, and

d) at least two connection points between the first layer and the second PCB, where the connection points are configured as a feeding interface to the patch antenna.

[0008] According to one aspect of the invention the micro chip module is further specified in that the module further comprises the footprint of SIM contacts added to the lowermost surface of the micro chip module so as to enable standardised connection to SIM connectors, or the module further comprises the footprint of memory card contacts added to the an outer surface of the micro chip module so as to enable standardised connection to memory card connectors. [0009] According to another aspect of the invention the micro chip module is further specified in that it further comprises an outer edge defining a perimeter of the first and the second PCB and also defining a vertical distance between the first layer and the second PCB.

[0010] According to another aspect of the invention the micro chip module is further specified in that the first upper layer has a single conductive layer facing downwards towards the second PCB.

[001 1] According to yet another aspect of the invention the micro chip module is further specified in that the second PCB includes one of: two conductive layers, three conductive layers or four conductive layers.

[0012] According to yet another aspect of the invention the micro chip module is further specified in that the radio transceiver module, the power regulating circuitry and other circuitry utilizes the ground layer as the platform for the layout on the second PCB.

[0013] According to yet another aspect of the invention the micro chip module is further specified in that at least one of the connection points are configured as flex bumps, flexible balls with conductive surface, a conductive probe made of conductive glue filled in a cylindrical hole or through a bending conductive part from one of the first layer or second PCB.

[0014] According to yet another aspect of the invention the micro chip module is further specified in that the flexible balls are adapted to be compressed during moulding.

[0015] According to yet another aspect of the invention the micro chip module is further specified in that the flexible balls are polymer balls with a conductive surface, where the conductive surface may be provided by any one of copper, silver or a combination of copper and silver.

[0016] According to yet another aspect of the invention the micro chip module is further specified in that the first layer and the second PCB is moulded together with the electrical circuitry there between fixed to the second PCB.

[0017] According to yet another aspect of the invention the micro chip module is further specified in that the housing is a SIM card. [0018] According to yet another aspect of the invention the micro chip module is further specified in that the connection points protrudes through a moulding layer applied on the second lower PCB.

[0019] According to yet another aspect of the invention the micro chip module is further specified in that the patch of the patch antenna is arranged on top of the moulding. The patch of the patch antenna can be screen printed on top of the moulding using conductive paste or conductive foil. Furthermore a non conductive layer can be arranged on top of the patch antenna.

[0020] According to yet another aspect of the invention the micro chip module is further specified in that the non conductive layer is the first upper layer.

[0021] According to the invention it is also provided a sheet of micro chip modules where each micro chip module comprises at least a patch antenna, at least one radio transceiver module and at least one power regulating circuitry. Each module have a form factor substantially similar to SIM cards or memory cards for portable devices and where the modules at least comprises:

a) a first upper non conductive layer,

b) a patch for each of the patch antennas adjacent to the first upper non conductive layer;

c) a second lower multilayer PCB being essentially congruent with the first layer and being opposite to the first non conductive layer, where the second multilayer PCB at least comprises; the at least one radio transceiver module, and a power regulating circuitry for each single micro chip module, and where at least one of the conductive layers of the second multilayer PCB is utilized as a ground layer to each of the patch antennas, and

d) at least two connection points associated to each module rising from the second PCB, where the connection points are configured as feeding interfaces to the patch antennas.

[0022] According to one aspect of the invention the sheet of micro chip modules is further specified in that the connection points protrudes through a moulding layer applied on the second lower PCB. [0023] According to another aspect of the invention the sheet of micro chip modules is further specified in that the patch of the patch antennas is arranged on top of the moulding.

[0024] According to yet another aspect of the invention the sheet of micro chip

modules is further specified in that the patch of the patch antennas are screen printed on top of the moulding using conductive paste or glued conductive foil.

[0025] According to the invention it is also provided a method of manufacturing one or more micro chip modules comprising at least a patch antenna, at least one radio transceiver module and at least one power regulating circuitry. The method at least comprises the steps of:

a) providing a second lower PCB;

b) providing electronic circuitry to an upper side of the second lower

PCB;

c) providing at least two connection points on upper side of the second lower PCB;

d) a moulding layer is pasted or transfer moulded to the second lower PCB;

e) a first upper layer is arranged on top of the moulding layer;

f) baking/curing the one or more micro chip modules,

g) applying one or more conductive layers on top of the first upper layer where these conductive layers constitutes one or more patch antennas, and

h) applying one or more layers of non conductive material over the

layers constituting the one or more patch antennas, thereby providing one or more micro chip modules.

[0026] Further objects and advantageous characteristics are achieved by the

features indicated in the dependent claims.

[0027] Further objects and advantages of the invention will be apparent from the following description with drawings. Identical elements are indicated by the same reference designations in the drawings. Brief Description of Drawings

[0028] The invention will now be described in greater detail in the form of exemplary embodiments with reference to the drawings, in which

[0029] Figure 1 illustrates a cross section of a WLANSIM card holder including

PCB's with electronic circuitry according to one embodiment of the present invention,

[0030] Figure 2 illustrates an upper layer and oppositely arranged lower layer PCB with connection points interconnecting said upper and lower layers, and

[0031] Figure 3 illustrates a WLANSIM card holder frame according to one aspect of the present invention. Illustration of WLANSIM low profile antenna, where radio modules and other components are mounted on a single or multi-layer PCB which also functions as a conductive layer for the antenna. The second conductive layer of the antenna, top layer is moulded together The

connection between the two layers can either be through vias made of conductive glue or so called flex-bumps, copper or gold preforms (pillars or studs), flexible polymer balls with conductive surface, or by letting the upper layer have a bending part that can be soldered down to the lower layer

[0032] Figure 4 shows an example of a power regulating circuitry,

[0033] Figure 5 shows another example of a power regulating circuitry,

[0034] Figure 8 shows a second lower PCB with components, and

[0035] Figure 7 shows the second lower PCB with moulding.

Mode(s) for Carrying Out the Invention

[0036] In the drawings and description that follows, like parts are marked throughout the specification and drawings with the same reference numerals,

respectively. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present invention is susceptible to embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that illustrated and described herein.

[0037] A general exemplification of the present invention will now be described with reference to the drawings.

[0038] According to the present invention it is disclosed a miniaturized card or micro chip module which typically can have the form factor of a SIM card or a nonvolatile memory card for use in portable devices such as digital cameras, cell phones, eBook readers, tablet computers, net book computers, media players, GPS receivers, and video game consoles. Typical examples can be Secure Digital (SD)-cards, Compact Flash I, Compact Flash II, Smart Media (SM), Memory Stick, Memory Stick DUO, MMC, i.e. an established

dimensional specification.. This miniaturized card is according to the invention provided with at least one radio transceiver, a patch antenna and belonging electronic circuitry. The miniaturized card is advantageously a complete standalone unit which interfaces with a portable device through SIM slot connections or through any type of memory card connections. The miniaturized card includes a low profile antenna where the layout with integrated transceiver module(s) chip(s) and other components constitutes one of two conductive layers. The components are moulded between the two conductive layers in the miniaturized card and a card frame. The miniaturized card provides a complete radio communication unit to the portable device to which it is connected.

[0039] In an alternative to the production of single miniaturized cards it is provided a micro chip module according to the above, however where a plurality of micro chip modules are arranged next to each other forming a sheet of micro chip modules. Each micro chip module can have the form factor of a memory card or a SIM card. Each of the micro chip modules comprises the same circuitry and antennas as indicated above. However it is not provided a moulding frame for each micro chip module rather the plurality of micro chip modules which forms the sheet of micro chip modules are designed as a multilayer sheet. A lower second PCB is arranged with circuitry for the plurality of micro chip modules, and with vias, preforms or flexible balls with copper/silver conductive surface associated with each single micro chip module rising from the lower second PCB. A moulding layer is pasted or transfer moulded to the PCB, this moulding will cover all the circuitry on the PCB and also fix components to the PCB. The preforms or vias may protrude through the moulding after the moulding process has been finished. With transfer moulding flexible balls with conductive surfaces are compressed in the moulding cap to create an interconnection to the patch antenna. Following the moulding and the baking of the moulding is the application of several patches to the patch antennas. The patches can be applied using screen printing with conductive paste. On top of this patch layer one or more layers may be added. A final layer with a non conductive layer facing upwards may constitute the uppermost layer in the sandwich construction. The finished sheet of micro chip modules will be cut into each single micro chip module by sawing, laser cutter, water jet or by any other suitable means for cutting such multilayer sheets.

[0040] In the following the wording connection point(s) may be used interchangeably for any type of connection points indicated above as preforms, vias etc.

[0041] One of the optional technologies for providing connection points deserves a further explanation. Balls made of polymers provided with a coating of conductive material are bonded/soldered to the PCB. The diameter of the balls are larger than the height/distance between the first 120, 220 and second 130, 230 PCB, in fact the diameter of the balls are larger than the total height of the finished component. The balls are compressed during the transfer moulding process. When the mould is removed the top of the balls are visible 741 , 742. Following the transfer moulding the patch antenna or patch antennas are arranged on top of the component/package 100. The at least one antenna layer is covered by at least one layer of non conductive film.

[0042] The conductive coating of the balls may be provided as a layer of copper, a layer of silver or a combination thereof. The patch antennas may be provided by screen printing a conductive paste such as silver paste or any other suitable conductive paste, alternatively the antenna may be provided by a conductive foil.

One embodiment of the present invention. [0043] According to one embodiment of the invention it is provided a complete standalone WLAN (Wireless Local Area Network) transceiver with a patch antenna which has the form factor of a SIM (Subscriber Identity Module) card, hence the complete WLAN transceiver is comprised in a SIM card. In the following description this embodiment is referred to as a WLANSIM 100.

[0044] According to this embodiment the WLANSIM includes a patch antenna and at least one radio transceiver module embedded in a SIM card 100. A patch antenna is one out of many possible antenna configurations; however a patch antenna will be operable as it establishes an electromagnetic field which is perpendicular to the surrounding printed circuit board. Other antennas such as for example F-antennas will establish an electromagnetic field which is parallel to the same structures, hence the field will be cancelled out. The WLANSIM 100 is designed with a first upper PCB (printed circuit board) 120, 220 which may comprise at least one first conductive layer, where the first conductive layer constitutes the patch layer or top layer of the patch antenna. Alternatively the top layer, the patch of the patch antenna, is arranged adjacent to the first upper PCB 120, 220 as will be described below.

[0045] The WLANSIM 100 further includes a second lower and opposite multilayer PCB 130,230 being essentially congruent with the first PCB 120,220 where the second multilayer PCB 130,230 at least comprises; the radio transceiver module, and a power regulating circuitry facing upwards. The second PCB 130,230 is according to this embodiment of a three layer type. One of the three layers is a ground plane and this ground plane is used as the ground plane to the patch antenna. The ground plane of the antenna thus functions as the platform for the layout of the integrated transceiver module, and other special function chips and components. In this embodiment the 3-layer PCB 130, 230 constitute a combined conductive layer of the antenna, as well as being the platform for the required layout with integrated circuits and components 150. Further, the radio transceiver module can be of an integrated type including a transmitter and a radio receiver, or it can be two separate modules. In the WLANSIM 100 configuration the transceiver module will normally be a WLAN transceiver which adheres to Wireless LAN network standards. Power Regulating Circuitry

The power regulating circuitry is an important part of the WLANSIM 100 configuration. A SIM must comply with ETSI and ISO standards with respect to current drawn by the SIM. In figure 4 it is shown a first example of a power regulating circuit according to one aspect of the present invention. It is not straight forward to run a WLAN transmitter on a SIM as the WLAN typically will draw 200mA at 3V, whereas according to ETSI standards only 50mA at 3V is available, hence a particular power regulating arrangement is necessary. The element Secure Element 453 complies with these standards. The Secure Element controls switching on and off the WLAN module 456. Current consumed by the Secure Element 453 is indicated by the control signals, shown as two-way arrows in figure 4. The Power regulator 454 draws all current available in compliance with the standards, after Secure Element has satisfied its need, and feeds a power storage bank 455. The power storage bank 455 may typically be a capacitor bank 455, or other suitable means with the capacity of storing electrical charges and also with the capability of miniaturisation. Feeding of the power storage bank 455 is maintained as long as the WLAN module 456 is operable and switched on and the power storage bank 455 is not fully charged. The WLAN module 456 draws current from the power storage bank 455. The WLAN module 456 will not send a "ready to transmit" signal to the Secure Element 453 before the charging level of the power storage bank 455 is at a level which suffices for transmitting at least one package of data. The Secure Element 453 can continuously send messages whether it needs more current or less current, hence the Secure Element 453 is the master in the power regulating circuitry 451. The WLAN module will advantageously monitor traffic continuously this typically draws 30 - 40 mA; this ensures safe receipt of all packages addressed to the WLAN SIM card 100. Received packages are

acknowledged by transmitting an ACK package. If it is not sufficient energy in the power storage bank 455 packages will be discarded and eventually the WLAN module will be disconnected. The size of the power storage bank 455 is restricted by the available space provided by the SIM. [0047] In figure 5 it is shown a second possible layout of a power regulating circuitry 551. According to this second design current is controlled commonly to the Secure element 553 and the WLAN module 556. The power regulator 554 according to this second design is also in direct electrical communication with a power storage bank 555.

[0048] The first PCB 120,220 and the second PCB 130,230 constitutes the top

120,220 and the bottom 130,230 of a SIM-card, with the above mentioned components 150 arranged there between. Circumferencing the top and the bottom is a frame 1 10,31 1 where the frame has the shape of a SIM-card and a height substantially similar to traditional SIM-cards. The second PCB 130,230 with its circuitry and the frame 1 10, 31 1 constitutes a moulding frame so that the first PCB 120,220 can be moulded together with the second three layer PCB 130,230.

[0049] Interconnection between the first PCB 120, 220 and the second PCB 130,

230 is provided by connection points 141 , 142, 241 , 242, 340, 641 , 642, 741 , 742. Note that connection points according to the present invention also includes performs and vias. The connection points can be made by conductive glue, flexible balls with conductive surface, by flex bumping (conductive probes) or simply by letting the one of the PCB's 120, 220, 130, 230 have a bending part that can be soldered or glued to the other PCB. Connection points 141 , 142, 241 , 242, 340, 641 , 642, 741 , 742 made by conductive glue can use a conductive probe made from conductive glue filled in separate cylindrical holes 340 made in the WLANSIM card holder frame 100, or alternatively by copper, or gold preforms (pillars or studs). The connection points 141 , 142, 241 , 242, 340, 641 , 642, 741 , 742are the feeding ports to the antenna.

[0050] The antenna is differentially fed, where impedance match is obtained by

reactive matching along with optimized length and characteristics impedance of the feeding lines. The antenna is electrically small, it is a low profile antenna and it is not self resonant. This also makes the antenna less affected by the close-in objects inside a mobile terminal. The transceiver module/chip has a differential feed interface to the antenna, or requires a balun if a single- ended fed antenna is used. A differential feed is known to be a better solution to reduce noise.

[0051] Preferably a low loss moulding material with a low TanD at the operation frequency of the antenna is used to mould the two PCB's 120, 220, 130, 230 together with the transceiver and other components between the two layers. Apart from favourable electric characteristics the moulding material shall also satisfy mechanical needs such as viscosity and adhesion characteristics. Preferably a low viscosity moulding material is used as this material will penetrate under flip chip mounted components and hence "glue" them to the PCB. The transfer moulding process is not restricted to this process.

Furthermore, the moulding material shall have suitable thermal properties so as to transfer heat from components and also have suitable coefficient of thermal expansion. In one embodiment two connection points (figure 6, 7) protrudes from the PCB and through the moulding. On top of the moulding (figure 7) a paste can be screen printed as a top layer of a patch antenna. The paste may be silver, solder paste or any other conductive paste suited for screen printing. In an alternative the antenna may be provided on top of the moulding using a conductive foil. On top of the antenna a non conductive layer will be provided.

[0052] Mounting of the components to the second PCB 130,230 can be done by using bonding, conductive glue or soldering technique or any combination of these mounting techniques.

A second embodiment of the present invention

[0053] According to a second embodiment of the invention it is provided a complete standalone WLAN transceiver with a patch antenna comprised in a miniaturized housing with a form factor such as a non-volatile memory card for use in portable devices of the type indicated above.

[0054] According to this embodiment the patch antenna and at least one radio

transceiver module is embedded in the miniaturized housing 100, where the housing 100 is provided with at least one radio transceiver, a patch antenna and belonging electronic circuitry 150. The miniaturized card includes a low profile antenna where the layout with integrated transceiver module(s) chip(s) and other components constitutes one of two conductive layers.

[0055] As will be appreciated by the person skilled in the art the second embodiment may be practiced in a fashion very similar to the WLANSIM configuration where the SIM is replaced with a miniaturized memory card of the types indicated above.

[0056] It shall be appreciated that the number of conductive layers in the first 120,

220 and the second PCB 130, 230 is a matter of design choice. Furthermore, the number of connection points 141 , 142, 241 , 242, 340 is also a matter of design choice as is the manufacturing method for providing said connection points.

Reference table

[0057]

100 The housing according to the invention which at least

includes a patch antenna, one or more transceivers and electronic circuitry,

1 10 The card holder, or the frame circumferencing the electronic circuitry and its belonging PCB's

120, 220 A first upper PCB

130, 230 A second lower PCB

141 , 142 Connection points

150 Electronic circuitry such as radio, transmitter or transceiver, power regulating circuitry etc.

241 , 242 Connection points

31 1 Card holder frame

340 Connection points, hole for conductive glue connecting the patch antenna

451 , 551 Power regulating circuitry

452, 552 Mobile terminal

453, 553 Secure element

454, 554 Power regulator

455, 555 Power bank, e.g. capacitor bank

456, 556 WLAN module

630, 730 PCB, with a form factor of a SIM or memory chip

641 , 642, Connection points, preforms

741 , 742