DE19732353A1 - Contactless chip-card manufacture method - Google Patents

Abstract

The method involves arranging an electrically conductive coil (2) on the surface of an insulating card (1). One or more non-packaged chips (4) are aligned in openings on the card surface. The electrical connections between the chip contacts and the coil contacts on the card surface are fabricated using flip-chip techniques. The card has openings may be made by injection moulding. The card body may be made of a thermoplastic material such as PVC, ABS or polycarbonate.

Description

Technical field

The invention relates to a method for producing contactless chip cards with mind at least one chip and a contactless chip card.

Smart cards are already being used in large numbers in all areas of private and public use life. Their performance is more integrated through the use of modern Circuits can be increased even further. Because by implementing more application-specific The area of application of chip cards can be used in the chip via identification and telecommunications to the following areas: In the healthy health care, for example with the insurance card, patient data card and emergency card. in the Communication area can use chip cards for access control to communication network zen and for billing of services as well as for the encryption and protection of Data are used. In payment transactions, chip cards are used as check cards, credit / debit card, electronic wallet and for charging in local transport and on Toll roads very well suited. Furthermore, chip cards are available for access control len and identification purposes, such as for pay TV, leisure services or Production control.  

Memory ICs and microcontrollers are currently used for chip cards. Furthermore, who the crypto controller in which an encryption key or algorithm implements is used in smart cards. The data exchange is through the contact areas with a reader or non-contact by capacitive or inductive transmission poses. The performance of modern chip card systems requires a constantly increasing Complexity and requires ever higher integration. In the beginning it was just storage with minimal periphery, so the development goes to more complex systems that one Microcontroller with various functions and coils for contactless communication require cation.

State of the art

In the known contactless chip cards there are one or more coils in the card body integrated, which are connected to the chip. The transmission of energy and data takes place through capacitive or inductive coupling. To build up these chip cards it is like this called "inlet technology" used. The coil and chip are made of plastic applied and fixed there. This carrier is then inserted into the actual chip card built. This can be done by extrusion coating or laminating the carrier. The carrier forms an integral part of the chip card after card installation.

As is known, carrier foils are used as carriers on which wound, etched or printed coil are formed. A baked enamel wire is used for the wound coil wound into a spool and manually applied to the carrier film and then connected to the chip. The main disadvantage here is the difficult application of the Coil on the chip card and the connections of the thick wires of the coil to the chip.

In contrast, the etched and printed coil on the carrier film have the advantage that the conductor tracks are an integral part of the carrier film. The chip is then through Wire bonding or flip-chip technology connected to the coil. Then the with Carrier and chip provided carrier film integrated into the card body. The disadvantage here are high manufacturing cost of the coil and the difficulty in laminating the  entire card body. The lamination is also disadvantageous for the thermal and mechanical resilience and thus for the life of the chip card. Especially we the temperatures prevailing during the encapsulation adversely affect the function of the expensive semiconductor chips. Added to this is that in the case of defects in the encapsulation, that is to say in the case of defects in a comparatively inexpensive plastic part, the card with the expensive semiconductor chip becomes committee.

From DE 44 41 122 z. B. be a method for producing contactless smart cards knows, with electrolyte copper is laminated on an approximately 50 µm thick film material and from this an antenna winding with pads on photoetching Ways is established. Furthermore, the film material is embossed with a lowered chip receiving area with a connecting zone adjoining it Mistake. The chip is then cemented into this receiving area and its contact surface Chen connected with bond wires to the pads of the antenna winding. On this assembled foil is closed on both sides with the exception of the chip receiving area glued between two equally thick plastic layers around the chip holder richly formed by approximately symmetrical recesses as shells. However, this method an additional embossing process for the chip receiving area as well a complex lamination and laminating process.

EP 0682231 A2 discloses a data carrier with an integrated circuit, one of which Coil as a flat coil using a hot stamping process in a card base body and in one depression located on this card side. An extra is made in the recess tes module, which has at least one integrated circuit and at least two contacts has elements, used and the contact elements are electrically ver with the coil bound. This data card requires too many individual manufacturing processes in total steps, especially since the module to be inserted into the card body that contains the integrated circuit circle contains, must also be prepared in several steps.  

Presentation of the invention

Starting from the prior art set out above, it is the task of the present Invention to provide a contactless chip card and a method for producing a to develop contactless chip card in such a way that the chip card is simple and inexpensive can be produced and has good mechanical strength and reliability.

An inventive solution to this problem consists in a method for the production contactless chip cards according to the features of claim 1 and a contactless Chip card according to claim 17. Preferred further developments are in the subclaims listed.

In the method according to the invention, an electrically insulating card body is first used made with one or more recesses on one side of the card body. Subsequently is directly on the surface of the card side provided with at least one recess applied at least one coil. After that, one or more bare chips or electronic components aligned in at least one of the recesses and the Pads of the chips with the connections of the coils by flip-chip technology electrically connected. The installation of bare chips is also called a nude chip assembly referred to because the bare or unhoused chip in the recess of the card body is used.

This has the advantages that compared to the lower height of the unhoused chips to the heights of the packaged chips or even chip modules, which are next to the chip contain additional function blocks, the depth of the recess can be selected so that firstly the unhoused and contacted chip does not protrude beyond the recess and that, secondly, the card cross-sectional thickness in the region of a recess is still so large that good mechanical stability is guaranteed. This is one with the invention Chip card with a minimal layer thickness and good mechanical resilience inexpensive to manufacture.  

In one embodiment of the invention, the card body is produced with a or multiple cutouts in a single work. This is advantageously done by injection molding, whereby the card body is integrally formed. Come here preferably thermoplastics, such as. B. PVC, ABS (acrylonitrile, butadiene, styrene) or Polycarbonates into consideration.

In a further embodiment of the invention, the surface, in particular the Floor surface, provided in the recesses with a predetermined surface shape. Contact bumps or spacing bumps are preferably formed in the cutouts det. In addition, it is advantageous to have the recess shape and the recess surface shape trained to match the special flip-chip contacting method used. The latter has the advantage that only the absolutely necessary recess volume from the Card body is omitted, which weakens the card body very little is and thus a high mechanical strength of the chip card is achieved.

In the invention, the coils on the surface of the with at least one Ausspa card side and both on surface areas outside the Aus savings as well as on surface areas within at least one of the recesses upset. This is preferably done in a single work, whereby for example the coils according to a hot stamping process under pressure and temperature application to the surface areas, in particular also to surface areas within at least one of the recesses.

The use of a heated embossing stamp, for example one, is particularly suitable for this Steel clichés on which the pattern of the coil conductor tracks is raised. With the coil conductor tracks made of a conductor foil, for example a copper foil, punched out according to the pattern and at the same time on the surface of the recesses containing card body side embossed. The liability of the coil conductor tracks on the Card body surface is in a preferred embodiment of the invention reached an adhesive layer on the underside of the conductor foil, the adhesive material is advantageously matched to the temperature and pressure during the embossing process.  

In a preferred embodiment of the invention, both the manufacture of the Card body, preferably by injection molding with a thermoplastic art fabric, as well as the application of at least one coil to the surface of the card body including the recesses or depressions in a single step. By this minimum of manufacturing steps is a particularly inexpensive manufacture and thus a production of large quantities can be realized. Added to this is the advantage of high mechanical and thermal resilience, firstly because the card is made of card body and card body provided with coil conductor tracks consists of very few layers (Minimum two layers: one-piece card body, layer of conductor tracks) and two At least the conductor tracks directly on the one-piece and thus mechanically and above all thermally stable card body is applied. The coil acts as an antenna for the contactless energy and / or data transmission with the outside world.

The depth of the recesses is preferably chosen so that it is impressed on the th coils, especially the coil connections contacted, unhoused chips protrude the recess. In one embodiment of the invention, the Spu Len pad (English: Pads) for the chip assembly simultaneously with the application of the Coil conductor tracks with embossed or formed. These pads are thus inte Grail component of the stamped coils.

The invention can be used very flexibly. Because depending on the application of the card due to the different chip pad geometries also changed contact area Chen or pad geometries to realize. This is with the invention can be implemented quickly and easily, and depending on the arrangement of the contact the most suitable contacting technology for the chips, such as flip-chip soldering or flip-chip gluing with isotropic glue or flip-chip gluing with anisotropic glue is used. In addition, the chip can also use a so-called contact pressure ver be flip-chip bonded with the coil connections. With the contact printing process Ren are bumps on the chip pads by an electrical insulating adhesive layer, which flä on the coil pads in the recesses chig is applied, pressed until it is in contact with the coil pads  Come in contact and under the influence of pressure and temperature and possibly ultra weld sound to these.

The flip-chip technology also has the advantage that it takes up little space on the one hand in the low amount of usable unhoused chips and thus the low Height of the chip card and on the other hand in a minimal cut-out volume to stop pressure comes. Both have the effect that the chip card has a minimal recess volume is only slightly weakened and thus has a high mechanical strength.

In a further exemplary embodiment of the invention, the chips are contacted Contact bumps used. In one embodiment, they are used simultaneously with the Application of the coil conductor tracks by means of the stamp shape from the card molded plastic and using one of the embossed coil conductor tracks with a Provide metallization layer. The Metallisie placed on a bump layer serves as a coil connection surface. In another embodiment of the inven a contact bump is placed on this coil pad.

In another exemplary embodiment, the contact bumps are already produced of the card body and the recesses, preferably in one single step, for example by injection molding the card body. At a Another embodiment is the contact bumps in the production of card base bodies preformed and hot stamping the coil traces into their final desired Formed.

Contact bumps also have the advantage that they have a minimal distance to the (Floor) surface can be set in the recesses and thereby the risk chip destruction when aligning and contacting is significantly reduced. In addition, must this distance control is then not taken over by the contacting device the.

In a further embodiment, in addition to those for contacting the chip see bumps provided so-called distance bumps. They cause  a minimum distance between the chip and the bottom surface of the recess is maintained is and are preferably placed so that the chip on the bumps and the Spacers are stable and planar. Because the bumps alone are enough Depending on the configuration of the chip pad, this is not always the case for the flip-chip contact to ensure necessary support stability of the chip. Furthermore, the through the contact or distance bumps achieved minimum distance in the embodiments of Invention necessary in order to increase the adhesive strength between the chip and the bottom a non-conductive adhesive is introduced by flowing under.

In a further exemplary embodiment, the cutouts provided with chips to protect against environmental influences and thus to increase the life of the card a potting compound, such as. B. a plastic or resin poured out. The Card thicknesses achieved through the use of bare chips that the contacted Chips do not protrude beyond the recess and after filling the recess with a Potting compound each chip is hermetically sealed and the recess side cards surface has no depressions and elevations.

Another exemplary embodiment includes the method step that does not refer to the off savings provided card body side a label is applied. This can, for example be printed and / or stamped out of the card body material shapes and, if necessary, colored with different colors. The method step of applying the label preferably takes place after the cards body was made with the recesses, but before the coils were applied become. Applying a label before contacting the chips has the big one Advantage that a thermal load associated with the label application, chemical Bela stung and / or mechanical stress, such as. B. pressure, bending, torsion avoided becomes. In principle, however, labeling can also be carried out on the coils after the chip has been mounted end faces. In a further exemplary embodiment, the geometric position the conductor tracks of a coil designed in such a way and the recesses placed such that also on the recess side card surface outside the recesses and outside the coil conductor tracks have sufficient space on which a label is applied.  

An embodiment of the invention in which the card body is particularly advantageous is provided with a label during the injection molding, as a result of which a one-piece body body with integrated label results. This saves at least one additional one Process step for labeling and is therefore particularly inexpensive.

Further advantages of the method according to the invention and the chip card according to the invention are listed below.

The invention allows the production of a card body in very few process steps pers with at least one recess, in particular by injection molding the card body by means of thermoplastic plastics, and with one on the recess-side card top surface applied structured metallization. This makes it simple and cost-effective low-cost production of cards possible. They are also characterized by chip cards produced by the invention by a high mechanical strength and Zu reliability. This is due to the small number of layers that make up the Chip card exists, and by the direct application of the coil on the one-piece card body. Material compatibility problems therefore occur with the invention Chip card not on. In addition, an intermediate carrier for the coil is inserted in this way saves.

Further advantages result from the use of the flip-chip technology for contacting the Chips: firstly the simple process flow, secondly the usability of unused housed chips and thus the minimal recess volume and the small chip cards thickness combined with high mechanical resilience and reliability. It is also in the In the case of flip-chip contacting, no wire-bondable metallization is necessary.

Another advantage is that the expensive and sensitive chips are only in one very late process step can be built into the card body and thus by the weni possible subsequent process steps far less harmful thermal, are exposed to chemical and physical loads. In particular, the chips not exposed to the thermal stress of an injection molding process in the invention.  

Ultimately, this guarantees fewer rejects and greater reliability and service life of the cards produced.

The invention will be based on drawings of exemplary embodiments wrote. Show it:

Fig. 1 Chip card (1) in plan view (recess side surface) with coil (2) with 10 coil turns and in a recess (3) embedded chip (4),

. Fig. 2 smart card (1) of Figure 1 in side view (section parallel to the longer edge of the card through the recess (3); section AB),

Fig. 3 shows an enlarged detail of the recess (3) with the contacted chip (4) from Fig. 2,

Fig. 4 enlarged section of the cross-sectional view of the recess ( 3 ) with con tact chip ( 4 ), the cutting plane being orthogonal to the cutting plane of Fig. 3 and the recess-side surface of the card body.

In one embodiment, the chip card ( 1 ) contains exactly one single recess ( 3 ) in which a square chip ( 4 ) is aligned and contacted with the conductor tracks of the coil ( 2 ). The shape and size of the recess was adapted to the shape of the chip. From Fig. 2 it can be seen that the depth of the recess is chosen so large that the contacted chip is completely immersed in the recess, so in particular does not protrude beyond the Kar surface ( 7 ). Fig. 3 shows the recess portion of the chip card in section in enlarged form (8), wherein the section plane is orthogonal to the conductor tracks (conductive paths in the direction of the normal vector of the cut surface). The contact bumps ( 5 ) molded out of the card body material ( 1 ), the material ( 6 ) used for the actual contact, an adhesive or a solder, and the conductor tracks of the coil ( 2 ) can be clearly seen in cross section. Fig. 4 shows a cross-sectional view through the cutout with an embossed coil, the cutting plane being orthogonal to the cutting plane of Fig. 3 and the recess-side card surface and passing through the contact bump ( 5 ). From Fig. 4 it can be seen that the picked-out conductor track ( 9 ) of the coil without interruption on the card surface outside the recess ( 9 a), on the side slopes of the recess ( 9 b) and the (bottom) surface of the recess ( 9 c ) is imprinted. At the location of the contact bump ( 5 ), the coil conductor track ( 9 ) runs over the contact bump ( 5 ) and thus causes a metallization of the contact bump ( 5 ).

In one embodiment for the method according to the invention for producing a contactless chip card, the first step is a card with a single recess or Recess made by injection molding with the plastic polycarbonate. After that you can the back of the card, i.e. the side or surface of the card that does not have a recess fung (and also no survey) has to be printed with a label. In a white The next step in the production of the card consists of a hot stamping foil, which is made of a cup layer on a carrier film, the coil conductor tracks according to a predetermined Pattern on the surface of the recessed card body side (recess-side surface) of the card, especially in the recess (MID technology: formation of conductor tracks on a three-dimensionally structured substrate; MID: Molded Interconnect Device). Typical temperatures and contact times are approx. 130 ° C to 150 ° C in a few seconds. On the contact or connection surfaces of the embossed coil conductor tracks in the recess of the card is now an isotropically conductive Glue dispensed. Outside the contact areas, at least part of the Surface in the recess another, electrically non-conductive adhesive for chip fixation dispensed. The chip is then inserted into the recess, aligned and bonded. To protect against environmental influences, the recess with the bonded chip filled with a sealing compound (glob top). If necessary, there will be another one Layer, such as a layer of sealant, on the filled depression as a cover brought. This multi-layer technique has the advantage of choosing suitable potting materials to be able to set the desired properties in a more targeted and better manner.

Claims (25)

1. A method for producing a contactless chip card, wherein an electrically isolating the flat card body is produced with one or more recesses on a card body side, further at least one electrically conductive coil is arranged on the surface of the card body side containing at least one recess, a Part of at least one coil is applied to both surface areas outside and surface areas inside the recesses, characterized in that one or more unhoused chips are aligned in the recesses and electrical connections between chip connection surfaces and connections of the coils are produced by flip-chip technology. 2. The method according to claim 1, characterized, that making the card body with one or more recesses in one single operation. 3. The method according to any one of claims 1 or 2, characterized, that by making the card body with one or more recesses Injection molding is done. 4. The method according to any one of claims 1 to 3, characterized, that when making the card body with one or more recesses Surface formed in a recess with a predetermined surface shape becomes. 5. The method according to claim 4,  characterized, that to produce a certain surface shape in the recesses or several spacing bumps are formed. 6. The method according to any one of claims 4 or 5, characterized, that to produce a certain surface shape in the recesses or several contact bumps are formed. 7. The method according to any one of claims 1 to 6, characterized, that a label is placed on the side of the card body not provided with recesses is brought. 8. The method according to any one of claims 1 to 7, characterized, that making the card body with one or more recesses as well forming the predetermined surface shape in the recesses in one single operation. 9. The method according to any one of claims 1 to 8, characterized, that uses a thermoplastic material as the material for the card body becomes. 10. The method according to any one of claims 1 to 9, characterized, that the application of the coils to the card body surface in a single Operation is carried out. 11. The method according to any one of claims 1 to 10, characterized,  that the coils are stamped on the card body by hot stamping technology. 12. The method according to any one of claims 1 to 11, characterized, that simultaneously with the application of one or more coils on the recess side surface of the card body in the recesses plastic contact bumps shaped and provided with a metallization layer by the coils. 13. The method according to any one of claims 1 to 12, characterized, that simultaneously with the application of one or more coils on the recess side surface of the card body in the recesses already existing Kon bumps are provided with a metallization layer by the coils. 14. The method according to any one of claims 1 to 13 characterized, that before aligning and contacting the chips, bumps as coils conclusions on the coil parts, which on surface areas in the recesses are embossed, are trained. 15. The method according to any one of claims 1 to 14, characterized, that contacting the chips by flip-chip soldering or flip-chip gluing, with isotropic glue or by flip-chip gluing with anisotropic glue. 16. The method according to any one of claims 1 to 15, characterized, that the recesses in which the chips electrically contacted to the coils are used with a potting compound, such as a plastic or resin be poured.   17. Contactless chip card consisting of an electrically insulating, one-piece Card body with one or more recesses on one side of the card body like one or more electrically conductive coils that are directly on surfaces areas of the card body side provided with at least one recess are arranged and have connections, characterized, that one or more bare chips that have chip pads in the Recesses are arranged and the chip pads with the connections of the Coils are electrically contacted by flip-chip technology. 18. Contactless chip card according to claim 17, characterized, that bumps are formed in the recesses that have a minimum distance cause between the chip and the bottom surface of the recess. 19. Contactless chip card according to one of claims 17 or 18, characterized, that bumps are formed in the recesses, the minimum distance cause between the chip and the bottom surface of the recess. 20. Contactless chip card according to one of claims 17 to 19, characterized, that the depth of the recesses is so large that the contacted chips do not have the Protruding recesses. 21. Contactless chip card according to one of claims 17 to 20, characterized, that the recesses are filled with a potting compound. 22. Contactless chip card according to claim 21, characterized,  that the recesses are filled with a potting compound such that the chips are hermetically sealed. 23. Contactless chip card according to one of claims 17 to 22, characterized, that the recesses are filled with a potting compound in such a way that the recess surface of the card body neither elevations nor depressions having. 24. Contactless chip card according to one of claims 17 to 23, characterized, that the material of the card body is a thermoplastic, such as. B. PVC, ABS or polycarbonate. 25. Contactless chip card according to one of claims 17 to 24, characterized, that the shape of a recess is adapted to the shape of the chip arranged therein is such that the recess volume is as small as possible.