Method of manufacturing a plurality of chip card modules and a flexible strip of material supporting the plurality of modules

Abstract

Method of manufacturing a chip card (1) module (2) in which a polymeric material (13) containing conductive particles is deposited in two connecting wells (12) or on two conductive pads formed in a conductive sheet positioned on the back of the module (2). The polymeric material (13) forms an excess thickness on the back after deposition, the excess thickness being in contact with the ends of the antenna (10) during the embedding of the module (2). Between the manufacturing of the plurality of modules (2) and their embedding, the plurality of modules are positioned on a tape which can be rolled up on itself for the purpose of its storage.

Description

Technical Field

[0001] This invention relates to the field of chip cards. Chip cards are well-known to the public and have various uses: payment cards, mobile phone SIM cards, fare cards, identity cards, etc. Existing technology

[0002] For example, a chip card includes transmission means for transferring data from the chip to a card reader device (reading) or from the device to the card (writing). These transmission means can be "contact," "contactless," or, when combining both, can have dual interfaces. This invention particularly relates to the field of dual-interface chip cards.

[0003] Dual-interface chip cards typically consist of a rigid support or card body made of polyvinyl chloride (PVC), polyvinyl chloride / acrylonitrile butadiene styrene (PVC / ABS), polyethylene terephthalate (PET), or polycarbonate plastics. The rigid support or card body constitutes the main part of the card, incorporating separately manufactured electronic modules and antennas. Therefore, the electronic module includes substantially flexible printed circuitry with an electronic chip (integrated circuit) and contact pads electrically connected to the chip and flush with the electronic module on the surface of the card body for establishing a connection through electrical contact with a card reader device. Dual-interface chip cards additionally include at least one antenna for transmitting data between the chip and the radio frequency system, enabling contactless data reading / writing.

[0004] Providing a robust and reliable electrical connection between the module and the antenna in a dual-interface chip card, capable of withstanding the processing operations the chip card may undergo, is relatively difficult. This connection must also be manufactured in a sufficiently economical manner.

[0005] Furthermore, before the chip card modules are used to finally complete the manufacturing of the chip card, and especially before the chip card manufacturing is finally completed by integrating each module into the card body and connecting each module to the antenna integrated into the card body, the chip card modules may have to be stored on the substrate for a relatively long period of time, which can be as long as several months.

[0006] To at least partially satisfy the above requirements, a method for manufacturing a chip card module is provided, the method comprising providing a dielectric substrate suitable for the production of flexible circuits. The dielectric substrate has a thickness defined by a front side and a back side, both of which form the main surfaces of the substrate. Furthermore, the method includes depositing a polymer material containing conductive particles. This deposition can be performed in connection wells to form connections with conductive pads located on the front side, or the deposition can be performed directly on conductive pads located on the back side. Thus, the polymer material containing conductive particles can be deposited in at least two connection wells formed within the thickness of the substrate, each of these connection wells being at least partially closed at the level of the front side of the substrate by contact pads formed in a first conductive metal sheet (which are thus deposited on the front side of the flexible circuit, corresponding to the contact surface (or contact side) of the module). Alternatively, the polymer material containing conductive particles can be deposited on conductive pads formed in a second metal sheet disposed on the back side (or adhesive side). Thus, optionally, the deposition of the polymer material containing conductive particles can be performed in the connection wells and on the conductive pads located on the back side. The deposition is carried out in a manner suitable for polymer materials containing conductive particles, thereby forming an excess thickness on the back side after deposition (in other words, if the back side does not include a second conductive sheet, an excess thickness is formed on the back side itself – for circuits of a single-sided module – or an excess thickness is formed relative to the second conductive sheet – for circuits of a double-sided module).

[0007] Following deposition, the polymer material containing conductive particles is cured. This curing stage is either spontaneously achieved or obtained through the implementation of one or more additional operations. More specifically, the polymer material containing conductive particles cures spontaneously and immediately after deposition due to its rheological properties and / or due to its thermal transformation, or cures immediately through the implementation of one or more additional operations (e.g., irradiation under ultraviolet radiation, exposure to a heat source, etc.) aimed at initiating and / or carrying out its complete or partial polymerization, or its complete or partial crosslinking. Curing occurs prior to storage operations, during which at least one substrate portion, comprising the first conductive sheet and the polymer material containing conductive particles, is positioned above or below another substrate portion. This is because, for storage purposes, the substrates can be rolled up themselves, or multiple substrate portions can be deposited one on top of another in the form of multiple plates. Optionally, the method includes the operation of crosslinking the conductive polymer material after the substrates have been rolled up or stacked on themselves. This crosslinking operation is intended to impart specific rheological properties to the conductive polymer material.

[0008] Due to the change in viscoelastic properties of the polymer material containing conductive particles during curing, multiple modules (already finished but not yet separated from each other) can be stored on a flexible material strip (in this case, a dielectric substrate) after deposition. The flexible material strip is stored using some of the substrate portions as coverings, and the polymer material containing conductive particles does not adhere to the portions of the strip located below or above it, nor to the insert material that can be placed between multiple rolled-up substrate portions or between multiple stacked substrate portions.

[0009] For example, when the polymer material containing conductive particles is a thermosetting polymer, an additional operation aimed at at least partially crosslinking the polymer material can be performed. This crosslinking operation can be performed when the substrate strip has been rolled up by itself or in the form of multiple plates stacked on top of each other. In the case of thermal crosslinking, the applied temperature is high enough (e.g., above 50°C) to impart its final properties to the polymer material, but low enough (e.g., below 150°C) to not harmfully affect other components of the module and to prevent the flow of uncrosslinked polymer.

[0010] Polymers containing conductive particles that are cured by temperature crosslinking, or by solidification due to cooling or also due to polymerization, become materials with a storage modulus that is less than or equal to 10 at oscillating stress at a frequency of 1 Hz and at temperatures between 120°C and 170°C. 8 Pa (100,000,000 Pa) and greater than or equal to 10 3 Pa (1,000 Pa). However, these properties of the polymer containing conductive particles, thus cured, remain compatible with the reactivation of adhesion and / or the reactivation of tack, which is sufficient to attach each module to the antenna by applying at least one pressure to the antenna's connection pad, and more specifically, to attach each module at least to the region where the polymer material containing conductive particles is located.

[0011] When pressure is applied to connect the module to the antenna, the increase in operating temperature can promote the reactivation of the adhesive properties of the polymer containing conductive particles. For example, this operation can be performed simultaneously with or instead of the operation involving attaching the module to the card body using hot melt adhesive.

[0012] Furthermore, the above methods advantageously include one or more of the following features, which are considered independently of each other or in combination with one or more other features:

[0013] - Deposition of a polymer material containing conductive particles is carried out at a temperature between 20°C and 120°C, for example, at a temperature between 20°C and 70°C.

[0014] - The polymer material containing conductive particles is a resin that, during its deposition, has a viscosity between 1000 mPa·s and 100000 mPa·s under oscillating shear stress at 10 Hz at 25°C; for example, the polymer material is a one-component or two-component resin; or, the polymer material is a thermoplastic resin having a melting point between 90°C and 140°C, and having a viscosity between 1000 mPa·s and 100000 mPa·s under oscillating shear stress at 10 Hz at 25°C during its deposition, wherein the deposition is carried out at a temperature between 90°C and 140°C; or, the polymer material is a pressure-sensitive polymer that, during its deposition, has a viscosity between 1000 mPa·s and 100000 mPa·s under oscillating shear stress at 10 Hz at 25°C.

[0015] - The polymer material containing conductive particles has thixotropic properties, characterized in that, under oscillating shear at a frequency of 0.1 Hz and at a temperature of 25°C, the viscosity increases to at least 300,000 mPa·s (and preferably higher than 500,000 mPa·s) within a time interval ranging from 0 to 600 seconds after the polymer material is deposited; this thixotropic property allows it to spontaneously cure; in this case, the method may not require an additional curing operation.

[0016] - The curing of polymer materials after deposition is achieved by cross-linking them under ultraviolet radiation within a time of less than 600 seconds after deposition.

[0017] According to another aspect, the present invention provides a method for interconnecting an antenna with a chip card module, the method comprising:

[0018] - Provide a chip card module obtained through the above method.

[0019] - Provides a card body in which an antenna is integrated, the antenna including at least two connection pads, and

[0020] - Connect at least one of two connecting pads to a contact pad or a conductive pad, the contact pad at least partially sealing the connection well, the connection well having a polymer material containing conductive particles deposited therein, the conductive pad being formed in a second conductive sheet disposed on the back side, the conductive pad having a polymer material containing conductive particles deposited thereon, the connection being made by applying a pressure between 0.5 and 5 bar for less than 3 seconds using a thermoelectrode at a temperature between 170°C and 210°C.

[0021] According to another aspect, the present invention provides a flexible material strip supporting a plurality of chip card modules, which are obtained by the method described above. The flexible material strip is either rolled up or in the form of a plurality of stacked plates (with or without insert material between two stacked layers of the strip).

[0022] According to another aspect, the present invention provides a dual-interface chip card, which includes modules and an antenna interconnected using the above-described method.

[0023] Other features and advantages of the present invention will become apparent from the specific embodiments and accompanying drawings, wherein:

[0024] - Figure 1 An example of a dual-interface chip card is shown schematically and three-dimensionally. The dual-interface chip card does not yet have an integrated module, which is shown three times, twice with a visible contact surface and once with a visible connection surface.

[0025] - Figure 2 An example of an implementation of a method for manufacturing a volume-to-volume chip card module is illustrated schematically.

[0026] - Figure 3 Shown in section, partially and schematically Figure 2 An example implementation of one of the multiple operations of the method shown corresponds to filling some connection wells with a material containing conductive particles;

[0027] - Figure 4 The image shows, in section, partially and schematically, a flexible material strip supporting multiple chip card modules before being wound onto a storage roll. The multiple chip card modules are... Figure 2 Obtained by the method shown;

[0028] - Figure 5 The passage is shown in section, partially and schematically. Figure 2 An implementation example of the operation obtained by the method shown, used for embedding a chip card module; and

[0029] - Figure 6 The diagram schematically illustrates the gripping of material containing conductive particles on multiple traces at the antenna end.

[0030] like Figure 1As shown, the present invention can be used in the production of a chip card 1 (bank card or other type of chip card). The card 1 includes a module 2 designed to be inserted into a cavity 3, for example, milled into the body of the card 1. The module 2 consists of flexible circuitry including a dielectric substrate 4. The substrate 4 initially exists in the form of a strip of material having a first main surface and a second main surface that are substantially parallel to each other and spaced apart by thicknesses. On the one hand, the substrate 4 has thickness, elasticity, and flexibility compatible with its use in a continuous roll-to-roll manufacturing method, and on the other hand, its thickness, elasticity, and flexibility are compatible with specifications and standards that determine the maximum thickness of the finished chip card. The embodiments of the method according to the invention described below and illustrated in the accompanying drawings relate to the roll-to-roll (or roll-in / roll-out) use of the substrate 4 and / or include at least one operation as a roll storage operation. Alternatively, the method according to the invention can be implemented with the substrate 4 existing in the form of a plate, and / or may include at least one operation as a plate storage operation of multiple substrates. The substrate 4 is substantially thin. Its thickness is advantageously less than 400 micrometers, for example in the range of 20 to 200 micrometers, and in fact even between 50 and 150 micrometers. For example, the substrate 4 is made of a flexible strip of plastic material (polyimide, PET, polyethylene naphthalate (PEN), PVC, etc.) or composite material (epoxy glass).

[0031] In the first conductive sheet 6, electrically insulating conductive pads are formed on one of the multiple faces of the substrate 4, referred to as the front face 5 (or contact face). These conductive pads may include multiple contacts intended to establish contact with a card reader and other multiple conductive pads not used for connection with the multiple contacts of the card reader. The multiple conductive pads can be formed by etching the first conductive sheet 6. The first conductive sheet 6 is made of a conductive material, such as a copper alloy (or aluminum, aluminum alloy, or steel may also be used as the conductive material). In this case, prior to its etching, the first conductive sheet 6 is bonded to and / or laminated onto the substrate 4, with or without an adhesive layer between the substrate 4 and the first conductive sheet 6. Alternatively, before the first conductive sheet 6 is bonded to and / or laminated onto the substrate 4 (again, with or without an adhesive layer between the substrate 4 and the first conductive sheet 6), the production of the conductive pads can be carried out in the first conductive sheet 6 using lead frame technology.

[0032] Therefore, in all cases, the first conductive sheet 6 is ultimately supported by the substrate 4, with one side facing the first main surface, which corresponds to the front side 5 of the substrate 4 (see [reference]). Figures 3 to 5Meanwhile, the other side is designed to establish a connection via electrical contact with a chip card reader. The first conductive pad 6 can receive various metallization layers (nickel, gold, palladium, etc.) on one and / or the other of its multiple sides. The quality of the (substantially metallized) side of the first conductive pad 6 facing the substrate 4 is important, thereby particularly ensuring a good connection to the chip 7 established by, for example, soldering of wires 8. The substrate 4, having multiple conductive pads 6, constitutes a metallized flexible circuit.

[0033] On the second main surface of the substrate 4, referred to as the back surface 9 (or connection surface), the substrate 4 supports the electronic chip 7. The mechanical fixation of the chip 7 to the substrate 4 is achieved using at least one prior art, such as die attachment, and the electrical connection of the chip 7 to the plurality of conductive pads is achieved using at least one prior art, such as flip chip bonding, wire bonding, etc. In the embodiments described below, wire bonding technology is used as an example.

[0034] Antenna 10 (e.g., of type 1 or type 2 size according to ISO 14443-1) may include several turns and is inserted into the body between two laminated layers of card 1. After milling of cavity 3, the plurality of ends 11 of antenna 10 are connectable in cavity 3 for connection to chip 7.

[0035] Multiple conductive pads, intended to form multiple contacts, are connected by multiple conductive lines 8 (in... Figure 1 Invisible in the middle, but in Figure 4 and Figure 5 (As shown in the diagram) A plurality of connection wells 12 formed in substrate 4 are connected to chip 7. For example, these connection wells 12 are formed by mechanically perforating substrate 4 before the first conductive sheet 6 is laminated to substrate 4. Alternatively, the plurality of connection wells 12 can be formed by laser (e.g., in the case of a laminated substrate using, for example, a copper laminate or copper clad laminate). The first conductive sheet 6 then at least partially covers the plurality of connection wells 12. Thus, the side of the first conductive sheet 6 facing substrate 4 forms the bottom of these connection wells 12. The plurality of connection wells 12 then form a plurality of blind vias, allowing access from the back side 9 to the front side 5, on which only the first conductive layer 6 is present.

[0036] Specifically, the size and position of multiple conductive pads are configured to meet the ISO 7816-2 standard. For example, according to the ISO 7816-2 standard, for a module 2 with eight contacts, multiple conductive pads are named C1 to C8. In this case, conductive pads C1, C2, C3, C5, C6, and C7 are configured to establish communication with the chip 7 through contacts on the front side 6. Therefore, at least two conductive pads are retained, each with a connection well 12 below it, and these at least two conductive pads can be used to participate in the connection from the antenna 10 to the chip 7. For this purpose, as... Figure 3 As shown, a polymer material 13 containing conductive particles is deposited into each of the two connection wells 12. Each of the two connection wells 12 is filled with the polymer material 13 by dispensing or jetting a drop of polymer material 13 (or, screen printing, can be used).

[0037] During the deposition of polymer material 13 in multiple connecting wells 12, polymer material 13 has thixotropic properties such that these properties can increase the viscosity to a value greater than 300,000 mPa·s under oscillating shear at a frequency of 0.1 Hz over a period of time ranging from 0 to 600 seconds after deposition.

[0038] Example 1: Two-component epoxy adhesive

[0039] According to the first example, chip 7 is fixed to the back surface 9 of substrate 4 using chip bonding technology, as described above. Chip 7 is electrically connected to conductive pads using connecting wires 8. Chip 7 and its multiple connecting wires 8 are encapsulated in encapsulating resin 15, which is cross-linked under ultraviolet radiation after deposition. In particular, this cross-linking can be carried out in two stages: a first stage shortly after deposition and a second stage, referred to as post-cross-linking, aimed at optimizing its mechanical properties.

[0040] Polymer material 13 is a two-component resin prepared by mixing two parts under conditions recommended by the supplier. Using dispensing equipment, the mixture thus prepared, constituting polymer material 13 containing conductive particles, is deposited into at least one connecting hole 12 at ambient temperature. Polymer material 13 is a two-component epoxy resin composed of, for example, an epoxy polymer and conductive particles of the type of silver particles.

[0041] When the polymer material 13 containing conductive particles is deposited in the plurality of connecting wells 12, the polymer material 13 containing conductive particles has a viscosity that is compatible with the deposition of the polymer material 13 distributed in the plurality of connecting wells 12. For example, under oscillating shear stress applied at 25°C and 10Hz, the viscosity is between 30,000 mPa·s and 60,000 mPa·s.

[0042] Following the dispensing of the polymer material 13 containing conductive particles, its viscosity immediately increases to over 500,000 mPa·s. This increase in viscosity allows material 13 to solidify without cross-linking at this stage of the process. The droplet shape of the thus solidified polymer material 13 remains stable in the absence of forces (e.g., finger pressure, liner pressure, contact with foreign objects, etc.). This increase in viscosity enables the substrate to be rolled up in rolls without altering the shape of the polymer material 13 initially given during dispensing.

[0043] The flexible substrate 4, thus self-wound, is placed at 70°C for 12 hours. This operation, initially intended to ensure post-crosslinking of the encapsulating resin 15, is advantageously used to simultaneously crosslink the conductive polymer material 13 pre-deposited by dispensing.

[0044] At the end of the crosslinking operation, for measurement temperatures between 120°C and 170°C, polymer material 13, under an oscillating tensile stress of 1 Hz, exhibits a tensile strength equal to 3.5 × 10⁻⁶. 7 Storage modulus Pa.

[0045] During embedding (involving the operation of integrating module 2 into the body of chip card 1), the polymer material 13, retaining the aforementioned viscoelastic properties, establishes an elastic electrical connection with each end 11 of antenna 10. Pressure is applied to module 2 at least at the level of the plurality of connection wells 12 filled with polymer material 13. This pressure is applied for a period of time using a thermoelectric electrode, the pressure being preferably close to or equal to 1 bar, the time being preferably close to or equal to 1 second, and the temperature of the thermoelectric electrode being between 170°C and 190°C.

[0046] Example 2: One-component epoxy resin

[0047] The difference between the method of the second example and the method described above regarding the first example (two-component resin) is essentially only that the polymer material 13 is a one-component epoxy resin. For example, the polymer material 13 is a resin whose trade names are included in the following list: Henkel CA3556HF, Henkel ICP8282.

[0048] Example 3: Thermoplastics with melting points between 100°C and 140°C.

[0049] According to the third example, chip 7 is fixed to the back surface 9 of substrate 4 using chip bonding technology, as described above. Multiple connecting lines 8 are used to electrically connect chip 7 to conductive pads. Chip 7 and its multiple connecting lines 8 are encapsulated in encapsulating resin 15, which is cross-linked under ultraviolet radiation after deposition.

[0050] Polymer material 13 is a conductive adhesive composed of, for example, a thermoplastic polymer and conductive particles. For example, polymer material 13 is a thermoplastic polyester resin containing silver particles.

[0051] The polymer material 13 containing conductive particles has a melting point of 100°C, and is then deposited in a plurality of connecting wells 12 at a temperature of 120°C.

[0052] When the polymer material 13 containing conductive particles is deposited in multiple connecting wells 12, the polymer material 13 containing conductive particles has a viscosity of less than 100,000 mPa·s.

[0053] Following the dispensing of the polymer material 13 containing conductive particles, and within a time interval of less than 600 seconds, the temperature of the polymer material 13 immediately drops below its melting point. This results in recrystallization, which allows the viscosity of the polymer material 13 to be increased to a value greater than 300,000 mPa·s. At this viscosity, the shape of the droplets of polymer material 13 deposited at the connecting holes 12 remains stable without force. The increased viscosity then allows the substrate 4 to be rolled up in rolls without altering the shape of the polymer material 13 initially given during dispensing.

[0054] Polymer material 13, at 1 Hz and at temperatures between 120°C and 170°C, has a strength of less than or equal to 10. 8 Pa (100,000,000 Pa) and greater than or equal to 10 3 Storage modulus of Pa (1,000 Pa).

[0055] During embedding, the polymer material 13, possessing the aforementioned viscoelastic properties, establishes an elastic electrical connection with each end 11. Pressure is applied to the module 2 at least at the level of the plurality of connection wells 12 filled with the polymer material 13. This pressure is applied for 2.5 seconds using a thermoelectric electrode, which advantageously approaches or equals 1 bar and has a temperature between 170°C and 190°C.

[0056] Example 4: Pressure-sensitive polymer

[0057] According to the fourth example, chip 7 is fixed to the back surface 9 of substrate 4 using chip mounting technology, as described above. Multiple connecting lines 8 are used to electrically connect chip 7 to conductive pads. Chip 7 and its multiple connecting lines 8 are encapsulated in encapsulating resin 15, which is cross-linked under ultraviolet radiation after deposition.

[0058] Polymer material 13 containing conductive particles is deposited in at least one connection hole 12 at ambient temperature. For example, polymer material 13 containing conductive particles corresponds to a formulation of acrylic monomers and oligomers containing conductive particles that can be polymerized by ultraviolet light (UV). For example, polymer material 13 containing conductive particles is a resin sold by Creative Materials under number 127-41.

[0059] When the polymer material 13 containing conductive particles is deposited, its viscosity is on the order of 20,000 mPa·s to 30,000 mPa·s under the following measurement conditions: oscillating shear stress at a frequency of 10 Hz, at a temperature of 25°C. This viscosity allows the polymer material 13 containing conductive particles to be distributed into the plurality of connecting holes 12.

[0060] Immediately after the dispensing of the polymer material 13 containing conductive particles, the flexible strip of the substrate 4 is exposed to ultraviolet radiation generated by a mercury vapor lamp for a period of time between several seconds (e.g., 2 seconds) and one minute. The polymer material 13 thus polymerized, containing conductive particles, forms a pressure-sensitive adhesive. After this polymerization, the shape of the droplets of polymer material 13 deposited at the plurality of connection holes 12 remains stable.

[0061] Alternatively, the encapsulating resin 15 can be post-crosslinked by exposing it to a temperature of 70°C for 12 hours.

[0062] At the end of polymerization, polymer material 13, under 1Hz oscillating shear stress at temperatures between 120°C and 170°C, exhibits 10 3 Energy storage modulus on the order of Pa.s (1,000 Pa.s).

[0063] During embedding, the polymer material 13 establishes an elastic electrical connection with each end 11 of the antenna 10. Pressure is applied to the module 2 at least at the level of the plurality of connection wells 12 filled with the polymer material 13. This pressure is applied for a period of time using a thermoelectric electrode, the pressure being preferably close to or equal to 1 bar, the time being preferably close to or equal to 2 seconds, and the temperature of the thermoelectric electrode being between 170°C and 210°C. In this example, the adhesiveness of the polymer material 13 contributes to creating a durable bond between the polymer material 13 and the plurality of ends 11 of the antenna 10.

[0064] In all cases, and particularly for the example described above, the deposition of droplets of polymer material 13 is carried out in a manner suitable for polymer material 13 containing conductive particles, so as to form an excessively thick dome on the back surface 9 after deposition. Figure 2 As shown, the deposition of a drop of polymer material 13 in a connecting well 12 can be performed continuously, roll-to-roll, after multiple operations such as photolithography (to form a conductive pad in the first conductive sheet 6) and electrodeposition of multiple metal layers (e.g., nickel, gold and / or palladium).

[0065] Advantageously, after the deposition of polymer material 13 in the multiple connecting wells 12 and optional coagulation or solidification operations, polymer material 13 only exhibits adhesive properties when it is subjected to pressure.

[0066] Upon completion of the process corresponding to the method described and illustrated by means of the above example, a flexible material strip 14 supporting multiple chip card modules is obtained. The strip 14 is then wound up, with or without insert material between the two stacked layers or two stacked turns of the strip 14. In other words, due to the properties of the polymer material 13 after solidification or curing, the polymer material 13 does not adhere to the multiple surfaces of the strip 14, which are in contact with the polymer material 13 during the winding of the strip 14 and during its storage as a roll. However, insert material can be used to ensure mechanical protection of the chip card modules.

[0067] Part of the belt 14 is in Figure 4 As shown in the diagram. For example, a portion of the strip 14 corresponds to the portion obtained after unfolding the strip 14 for embedding the plurality of modules 2 included in the strip 14. In the shown portion, there are two modules 2. Each module 2 includes a chip 7, which is connected to a plurality of contacts etched in a first conductive sheet 6 via a plurality of wires 8 passing through a plurality of connection wells 12. Each chip 7 and the plurality of wires connected to each chip 7 are protected by an encapsulating resin 15 (top encapsulation). Outside the encapsulating resin 15, which is therefore not covered by the encapsulating resin 15, at least two connection wells 12 are reserved for each module 2. Each of these two connection wells 12 is filled with a solidified, cured polymer material 13. The polymer material 13 protrudes excessively on the back surface 9. For example, the polymer material 13 protrudes at a height between 60 micrometers and 250 micrometers; for example, this height is close to 150 micrometers.

[0068] Before embedding, multiple modules 2 were separate from each other. For example... Figure 5As shown, each module 2 is embedded by placing it in a cavity 3 pre-milled within the body of the card 1. Specifically, the milling exposes multiple ends 11 of the antenna 10. For example, each of these ends 11 is provided with a smaller conductive plate, to which each end 11 is connected (e.g., by welding). Alternatively, the multiple ends 11 may form zigzags. Figure 6 As schematically shown, the zigzag pattern comprises multiple traces 20 (formed by multiple lines in a recessed support member, or by multiple strips etched in a conductive layer supported by an insulating substrate). The spacing between the multiple traces 20 determines the pitch. These traces 20 are spaced apart from each other with a regular pitch of either a large or small (in... Figure 6 (The multiple ends of the multiple traces 20 that are interconnected to form a zigzag pattern are not shown in the image.) Figure 6 On the left side, multiple traces 20 are spaced apart by a pitch P1, which is greater than the pitch P2 of the multiple traces 20 shown on the right side. As a result, the dome of material 13 containing conductive particles filling the connection hole 12 has fewer electrically connected traces 20 in the arrangement shown on the left side compared to the arrangement shown on the right side (3 traces on the left, 4 traces on the right). Therefore, advantageously, the pitch of the multiple traces 20 forming a zigzag pattern is less than or equal to 250 micrometers, and more preferably close to or equal to 200 micrometers. If the multiple traces are too far apart, it is possible that the material 13 containing conductive particles, especially if it is not centered relative to the zigzag pattern, will no longer establish sufficient electrical connections with the multiple ends 11 of the antenna 10.

[0069] Optionally, a hot melt adhesive is used to adhesively bond the module 2 to its cavity 3, and during the adhesive bonding of the module 2 to its cavity 3, pressure is applied to the polymer material 13 at the level of the hot melt adhesive.

[0070] Essentially, when polymer material 13 is deposited in connecting well 12, polymer material 13 advantageously has a viscosity of less than 100,000 mPa·s, which is measured under oscillating shear stress at 25°C and at a frequency of 10 Hz. Following this deposition, polymer material 13 either spontaneously cures or undergoes a curing process to achieve a viscosity of 10 mPa·s under oscillating shear stress at a temperature between 120°C and 170°C. 3 Pa.s (1,000 Pa.s) and 10 8 Storage modulus between Pa.s (100,000,000 Pa.s). During embedding, the polymer material 13 is subjected to pressure and may also be heated, thereby reactivating its adhesive properties and / or viscousness.

[0071] The manufacturing method of a single-sided module 2 has been described above, whereby the single-sided module 2 comprises only a first conductive sheet 6 on its front side. In this case, polymer material 13 is deposited in a plurality of connection wells 12. However, the present invention also relates to a manufacturing method of a double-sided module 2. In this case, the substrate 4 includes a first conductive sheet and a second conductive sheet on each of its plurality of main surfaces. Polymer material 13 can then be deposited on a conductive pad formed in the second conductive sheet, wherein the conductive pad is therefore on the back side of the substrate 4. Several operations following the deposition of polymer material 13 on these conductive pads are similar to those described above regarding the production of a single-sided module.

Claims

1. A method for manufacturing at least one chip card (1) module (2), comprising: - A flexible dielectric substrate (4) is provided as a strip, the substrate (4) having a thickness defined by a front side (5) and a back side (9), the front side (5) and the back side (9) each forming a plurality of main surfaces of the substrate (4), wherein at least one conductive pad is formed in a first conductive sheet (6) disposed on the front side (5). - The polymer material (13) containing conductive particles is deposited in a manner suitable for a polymer material (13) containing conductive particles, so as to form an excess thickness on the back side (9) after deposition, the deposition being carried out according to at least one of the following two options: In at least one connecting well (12) formed in the thickness of the substrate (4), the connecting well is at least partially closed by a conductive pad formed in the first conductive sheet (6) at the level of the front side (5) of the substrate (4). On the conductive pad formed in the second conductive sheet, the second conductive sheet is disposed on the back side (9). Its features are: - The polymer material (13) containing conductive particles exhibits a viscosity between 1000 mPa·s and 100000 mPa·s upon deposition, the viscosity being measured under oscillating shear stress at 25°C and at a frequency of 10 Hz. - The method includes a curing stage of the polymer material (13) containing conductive particles, and - A storage operation, comprising the self-rolling of the substrate (4) having the first conductive sheet and the polymer material (13) containing conductive particles, or the stacking of multiple portions of the substrate (4) existing in the form of multiple plates, the storage operation being performed after the curing stage and before an operation involving the integration of the at least one module (2) into the body of the chip card (1), and during the storage operation, at least a portion of the substrate (4) having the first conductive sheet and the polymer material (13) containing conductive particles, is positioned above or below another portion of the substrate (4), the other portion of the substrate (4) being derived from the self-rolled substrate (4), or from a plate of the substrate (4) deposited above or below the at least portion of the substrate (4), the plate having the first conductive sheet and the polymer material (13) containing conductive particles, the polymer material (13) containing conductive particles being disposed by the curing stage so as not to adhere to the other portion of the substrate (4), and thus at least by the application of pressure, enabling the at least one module (2) to be connected to the antenna (10).

2. The method according to claim 1, wherein the polymer material (13) containing conductive particles is, after curing, under oscillating stress at a frequency of 1 Hz and at a temperature between 120°C and 170°C, having a strength of less than or equal to 10. 8 Pa (100,000,000 Pa) and greater than or equal to 10 3 Materials with a storage modulus of Pa (1,000 Pa).

3. The method according to any one of claims 1 to 2, wherein the deposition of the polymer material (13) containing conductive particles is carried out at a temperature between 20°C and 70°C.

4. The method according to any one of claims 1 and 2, wherein the polymer material (13) containing conductive particles is a thermoplastic resin having a melting point between 90°C and 140°C, and wherein the deposition of the polymer material (13) is carried out at a temperature between 90°C and 140°C.

5. The method according to any one of claims 1 to 2, wherein the polymer material (13) containing conductive particles is a pressure-sensitive adhesive.

6. The method according to any one of claims 1 to 2, wherein the polymer material (13) containing conductive particles has thixotropic properties, characterized in that... The viscosity, under shear stress at a frequency of 0.1 Hz, becomes greater than 300,000 mPa·s after a time ranging from 0 to 600 seconds following the deposition of the polymer material (13).

7. The method according to any one of claims 1 to 2, wherein the polymer material (13) containing conductive particles is cured by exposing it to ultraviolet radiation.

8. The method according to any one of claims 1 to 2, wherein the polymer material (13) containing conductive particles is heated after deposition.

9. The method according to any one of claims 1 to 2, wherein the polymer material (13) containing conductive particles forms an excess thickness on the back side (9), the height of the excess thickness being between 60 micrometers and 250 micrometers.

10. A method for interconnecting an antenna (10) of a chip card (1) with a module (2), comprising: - Provide a chip card (1) module (2) obtained by the method of any one of claims 1 to 9. - Provide a card body in which an antenna (10) including at least two connection ends (11) is integrated. - Connect at least one of the two connection ends (11) to a conductive pad formed in the first conductive sheet (6) that at least partially closes a connection well (12) in which a polymer material (13) containing conductive particles is deposited, or connect at least one of the two connection ends (11) to a conductive pad formed in the second conductive sheet disposed on the back side (9) on which a polymer material containing conductive particles is deposited.

11. The interconnection method of claim 10, wherein the connection is made by applying a pressure between 0.5 bar and 5 bar for less than 3 seconds using a thermoelectric electrode at a temperature between 170°C and 210°C.

12. The interconnection method according to claim 10 or 11, wherein the connection between the antenna (10) and the chip card (1) module (2) is made by applying the polymer material (13) containing conductive particles to the zigzag end of the antenna (10), the zigzag comprising multiple traces spaced apart from each other with a pitch of less than 250 micrometers.

13. A flexible material strip (14) supporting a plurality of chip card modules (2), the plurality of chip card modules being obtained by the method according to any one of claims 1 to 9, wherein the flexible material strip (14) is rolled up or is in the form of a plurality of plates stacked on top of each other.

14. The flexible material strip (14) according to claim 13, wherein the polymer material (13) containing conductive particles forms an excess thickness on the back side (9) of each of the plurality of modules (2), the excess thickness having a height between 60 micrometers and 250 micrometers.

15. A dual-interface chip card (1) comprising a module (2) and an antenna (10) interconnected using the method according to any one of claims 10 to 12.

Images