WO1999050790A1

WO1999050790A1 - Method for making chip cards

Info

Publication number: WO1999050790A1
Application number: PCT/FR1999/000706
Authority: WO
Inventors: Stéphane AYALA; Frédéric VICENTINI
Original assignee: Gemplus
Priority date: 1998-03-31
Filing date: 1999-03-26
Publication date: 1999-10-07
Also published as: AU2939399A; JP2002510101A; FR2776796B1; FR2776796A1; EP1073996A1

Abstract

The invention concerns a method for making a chip card comprising an interface for external communication and at least an electronic component (4) emerging at the surface. Said method is characterised in that it consists in connecting the electronic component (4) to the communication interface by means of conducting wires; temporarily fixing the electronic interface-electronic component assembly against a first plastic wafer (11); placing a second plastic wafer (23) on the electronic assembly, an opening (24) being provided either in the first wafer (11) or in the second wafer (23) to house the electronic component (4); and in making the two wafers (11 and 23) integral by closing the interface and the electronic component.

Description

METHOD FOR MANUFACTURING CHIP CARDS

The present invention relates to the manufacture of smart cards comprising a communication interface with one exterior and at least one electronic component opening onto the surface. The term "smart card" is intended to mean any type of card which can operate with and / or without contact, that is to say that cards which can communicate with the outside by means of conventional standard contacts are envisaged, cards which can communicate with the outside via an antenna integrated in the card, or finally mixed cards which can communicate with the outside either via the antenna or via the conventional contacts.

A communication interface is defined according to the type of operation of the smart card. Thus, when the smart card is a contact-functioning card, the interface includes an integrated circuit module having access contacts intended to be flush with the surface of the card. When the card operates without contact, the interface includes an integrated circuit module connected to an antenna and embedded in the card body. Finally, when the card is a mixed card, the interface includes an antenna connected to an integrated circuit module having access contacts intended to be flush with the surface of the card.

Chip cards are intended to carry out various operations such as, for example, banking operations, telephone communications, identification operations, debit operations or recharging of account units, and all kinds of operations which can be done either by inserting the card in a reader, or remotely by coupling electromagnetic (in principle of the inductive type) between a transmission-reception terminal and a card placed in the zone of action of this terminal. The installation of a display in a smart card can be useful in particular for making an electronic purse in order to allow viewing of the amount remaining in the purse, for example.

Chip cards should preferably have standardized dimensions identical to those of conventional chip cards with contacts. This is obviously particularly essential for mixed cards and it is desirable for cards operating only in contactless mode.

The usual ISO 7810 standard defines a card 85 mm long, 54 mm wide and 0.76 mm thick. The contacts are flush with well-defined positions on the surface of the card.

These standards impose severe constraints for manufacturing. The very small thickness of the card is in particular a major constraint, even more severe for contactless cards and comprising several electronic components than for cards simply provided with contacts, since it is necessary to provide for the incorporation of both a antenna and electronic components and the creation of multiple interconnections.

The integration and connection of electronic components such as displays, for example, in rigid and / or bulky objects have found a number of technical solutions. On the other hand, the integration of a flexible display in a flexible card and of such a thin thickness has not yet been approached to date.

The technical problems which arise are problems of positioning of the various components problems in the card body, problems of adhesion of these components, problems of arrangement, in the card body, of the interconnections between the different electronic components and problems of precision and reliability of the connections with respect to the mechanical stresses on the card. Manufacturing cost constraints must also be taken into account.

The object of the invention is to propose a manufacturing method capable of best solving these problems of positioning, manufacturing precision, mechanical strength, and more generally of reliability, cost and production efficiency of the card.

For this, the invention provides a method of manufacturing a smart card comprising a communication interface with one exterior and at least one electronic component opening onto the surface, mainly characterized in that the electronic component is connected to the interface of communication by means of lead wires; the electronic assembly interface - electronic component is temporarily fixed against a first plastic plate; a second plastic plate is placed on the electronic interface - electronic component assembly, an opening being provided either on the first plate or on the second plate to serve as housing for the electronic component; and the two plates are secured by enclosing the interface and the electronic component. This process is simple and inexpensive. It makes it possible to reliably and precisely solve the problem of electrical connection between the electronic component (s) and the communication interface: the electrical connections are made before installation of the whole in a plastic card. The electronic component (s) and the communication interface are correctly placed in the card.

The invention further provides another embodiment of a method for manufacturing a smart card comprising a communication interface with one exterior and at least one electronic component opening onto the surface. According to this other embodiment, conductive tracks are produced on a flexible plastic sheet to form a printed circuit; the communication interface and the electronic component are fixed on the printed circuit obtained so that contact pads of the interface are connected to contact pads of the electronic component by means of the conductive tracks, - provisionally fixed the electronic printed circuit - interface - electronic component assembly against a first plastic plate; a second plastic plate is placed on the electronic printed circuit - interface - electronic component assembly, an opening being provided either on the first plate or on the second plate to serve as housing for the electronic component; and the two wafers are joined together by enclosing the electronic printed circuit - interface - electronic component assembly.

Other particularities and advantages of the invention will appear on reading the detailed description given by way of illustrative example and made with reference to the appended figures which represent:

FIG. 1, an electronic assembly comprising a module, a display, an antenna, a battery and a microcontroller, Figure 2, the establishment of the electronic assembly of Figure 1 against a plastic plate in the format of the smart card, provided with an adhesive sheet, - Figure 3, the establishment of a another plastic plate to cover the electronic assembly, FIG. 4, the card finished at the stage of removal of the adhesive sheet and ready to be used,

FIG. 5, another finished card and priest to be used, manufactured according to an alternative embodiment, at the stage of removal of the adhesive sheet provided on each of the plastic plates enclosing an electronic assembly,

- Figure 6, a perspective view in exploded form of the various elements necessary for the manufacture, according to another embodiment, of a smart card comprising a display, - Figure 7, a perspective view in form exploded view of the various elements necessary for the manufacture, according to another embodiment, of a smart card comprising a display.

In Figure 1 is shown an example of an electronic assembly having different elements connected together. This representation is not limiting and it is understood that the architecture of the chip card according to the invention may include several, or fewer, of electronic components. In fact, the smart card according to the invention comprises at least one interface for communication with the outside and an electronic component opening onto the surface. In the example shown in FIG. 1, the communication interface comprises an integrated circuit module 2 1 connected to the ends of an antenna 5, and the electronic component emerging at the surface is a display 4.

The antenna 5 is a simple wire wound flat, the inherent rigidity of the wire being sufficient for the antenna to be manipulated during the inserting operations while keeping its overall planar shape. This antenna represents an inductor allowing remote communication by electromagnetic coupling of the inductive type. The wire can be coated with an insulator avoiding contact between adjacent turns. In any case, an insulator is provided if the turns cross (case where there are several turns). But the ends of the wire are stripped for their electrical connection to an integrated circuit module. The dimensions of the antenna 5 are, for reasons of electromagnetic efficiency, very close to the external dimensions of the smart card. An integrated circuit module 2 1 is then electrically connected to the antenna 5 by fixing the ends of this antenna on two connection pads of the module 2. The module 2 also has other contact pads on its periphery, which can be electrically connected to the contact pads of a display 4 by means of flat conductive wires 7. The term "display" is intended to mean any electro-optical device making it possible to display information passing through in the form of electrical signals, and which can be produced in flexible form so as to withstand the usual deformations of cards. The display could for example be of the liquid crystal, electrochromic, electrophoretic, or other type. The display is intended to be connected to the integrated circuit chip of the card, in order to view the information that it contains. In FIG. 1, the integrated circuit 1 of the module 2 is connected, via its contact pads and conductive wires 7 flat, to a micro-controller 3 intended to control the display 4. In this case, the microcontroller 3 also has contact pads and it is itself electrically connected to display 4 via - other flat conductive wires 6. On the other hand, the microcontroller 3 can also be connected to a battery 8 via flat conductive wires 9.

The conductive wires 6 for connecting the microcontroller 3 to the display 4 can moreover be replaced by one or more flexible films comprising conductive tracks. FIG. 2 represents, in longitudinal section, the antenna-module-display-microcontroller-battery electronic assembly of FIG. 1, after soldering the various connections between the elements; however, the battery is not shown in this figure for the sake of clarity. This figure also shows a plastic plate 11, which may already be in the format of a smart card or which will be cut later in this format. The plastic material can be polyvinyl chloride (PVC) or polyethylene terephthalate (PET) or another plastic material.

This plate 11 constitutes a part of the body of the smart card. It has one or more openings that can serve as housing for the module 2 and the display 4. In the example shown in FIG. 2, it has two openings 14 and 13 intended to receive the module 2 and the display 4 respectively. These openings 13 and 14 pass through the entire thickness of the wafer. The dimensions of each of the openings are adjusted in relation to the dimensions of the element that they are intended to receive. The position of the opening 14 reserved for the module 2, relative to the format of the wafer 11, corresponds to the standardized position of the contacts of a smart card.

The rear face of the wafer 11 is coated with an adhesive sheet 12, the adhesive face of which is applied against the wafer. This sheet 12 covers the openings 13, 14 so that it constitutes a bottom for the housings made in the card by the openings 13 and 14. This bottom is adhesive.

The module 2 comprises an integrated circuit 1 covered with a protective resin 15, the antenna wires 5 are shown in section as well as the interconnection wires 6 and 7.

The display 4 is constituted by an assembly of two substrates 16, 17 between which are arranged liquid crystal or electrochromic or electrophoretic materials for example. The substrates 16 and 17 are provided with conductive tracks making it possible to generate the electro-optical effects of the active materials included between these two substrates. These conductive tracks are also connected to the electrical connection 6. In the example shown in FIG. 2, the substrate 16 is shown longer than the substrate 17 so as to allow the electrical connection 6 with the microcontroller 3.

It is also possible to ensure that the substrate 17, which is intended to be flush with the surface of the card, is longer than the substrate 16, and then to make the electrical connection to the substrate 17 which will lead to the surface of the map.

The elements are shown here assembled and positioned opposite the plastic plate 11 and its openings 13 and 14, just before they are placed on this wafer 11, according to the arrows shown in FIG. 2.

When they are placed on the wafer 11, the elements intended to reach the surface of the card, that is to say, in the example shown, the module 2 and the display 4, are inserted respectively in the openings 14 and 13 and are bonded by the adhesive material of the sheet 12. In an alternative embodiment, it is possible to position in the first place some or all of the elements in the openings of the plastic wafer 11 or thereon then, in the second place , to connect, via flat conductive wires, the elements thus positioned at their final location in the card body. This solution makes it possible to solve the problems of positioning the elements with respect to each other.

As indicated in FIG. 3, a resin 18, or a heat-activatable adhesive film, is then deposited on the assembly thus defined, then the assembly is covered with a second plastic plate 19 itself cut in card format or which will be cut later in this format. The assembly thus formed is hot or cold rolled, to secure the two external plates 11 and 19 by enclosing the electronic assembly. For cold rolling, the insertion of a bonding resin (which may be resin 18 mentioned above) is necessary. FIG. 3 represents the smart card at this stage, with the wafers 11 and 19 on either side of the electronic assembly, and a binder resin 18 embedding the assembly between the wafers. 10

The last operation (FIG. 4) consists in peeling off the adhesive sheet 12, then showing, on the surface of the chip card, the stripped contacts of the integrated circuit chip of the module 2 and the display screen of the display 4.

FIG. 5 represents a finished smart card and manufactured according to an alternative embodiment. In this variant, the display is placed on the back of the card. This example is limited to a single element on the front (module 2) and a single element on the back (display 4) of the card, but it is of course possible to insert several elements on the surface of the card, front as on the back of this one.

In this variant, the electronic assembly is placed on a first plastic plate 11 provided with a single opening 14 intended to receive the module 2. A second plastic plate 23 provided with a single opening 24 intended to receive the display 4 is then brought next to the electronic assembly. Another adhesive sheet 22 is glued to the second plate 23 to cover the opening 24 and to position the display, in the bottom of the housing created by the opening 24, at the exact dimension.

After the deposition of resin 18 or of a heat-activatable adhesive film, the two plates 11 and 23 are laminated, hot or cold, in order to join them together by enclosing the electronic assembly. Finally, the last step consists, in this case, of peeling off the two adhesive sheets 12 and 22 to reveal, on the faces of the card, the contacts of the chip of module 2 on the front and the display screen of the display 4 on the back.

FIG. 6 represents in perspective and in exploded form elements of constitution of a smart card comprising a communication interface (module 2 connected 11

to an antenna 5) and a display 4 and manufactured according to another embodiment.

In this other embodiment, the electronic components are connected to a flexible and thin printed circuit 10. The printed circuit 10 can for example be produced on a sheet of plastic metallized by usual techniques and cut to the format of the card. An antenna, which is not shown in FIG. 6 for reasons of clarity, as well as conductive tracks 6, 7, 9 making it possible to connect the various electronic components to each other, are for example produced by screen printing of conductive ink, by depositing metallizations on the plastic sheet, or by inlaying a copper wire in the plastic. As with the other manufacturing processes which have just been described, it is preferable to deposit on the electronic assembly, before positioning the second wafer 19, a thermosetting resin. In this case, the resin serves both as a material to give cohesion to the card body but it also allows the adhesion of the various plates 11, 19 with the printed circuit 10 and / or the electronic components.

In another variant, and as shown in FIG. 6, instead of depositing a resin, it is possible to deposit on the electronic assembly another plastic sheet 20, also called "core", provided with cavities and / or through openings 21 intended to receive the electronic components arranged on the printed circuit, prior to the positioning of one of the plates 11 or 19. The cavities 21 also make it possible to maintain the electronic components in their position. Their dimensions are adjusted to the dimensions of the components associated with them. 12

The number of plastic sheet (s) thus constituting the heart of the card is not limiting. One could for example provide several other sheets so as to avoid the effects of reliefs or the lack of cohesion of the card due to the cavities 21 present in the "core" sheet 20 of the card.

In this case, the different plastic sheets 20, plates 11, 19 and the printed circuit 10 can be assembled using the laminating technique. This can be obtained by fusing the plastic plates and sheets together; or preferably by coating the plastic sheets and the printed circuit with one or more types of adhesives, these adhesives being activated during the final lamination step. Adhesives which can be activated at temperatures and pressures compatible with the electronic components and the display present in the card body will preferably be chosen.

In another alternative embodiment, shown in FIG. 7, it is possible to envisage the possibility of placing components on the surface on both sides of the card, for example the contacts of module 2 on the front side and the display screen of the '' display 4 on the back side. In this case, a double-sided printed circuit 10 is produced comprising metallizations 6, 7, 9 on its two faces, and conductive vias 30 for connecting the metallizations on one face to the metallizations on the other face. An opening 24 is also provided on an external plate 23 for placing the display 4 there and an opening 14 on the other external plate 11 for placing the module 2. Thus, after having detached the adhesive sheet 12 from the plate 11 and the adhesive sheet 22 of the other wafer 23, a card is obtained comprising 13

contacts flush on the front and a display screen on the back.

The adhesive sheets 12 and 22 are however not essential when using the core plastic sheet because the thickness dimensions of this sheet are well adjusted so that certain components can open onto the surface of the card. Adhesive sheets are necessary when using soft, thermosetting resin, to retain components on the surface by the adhesive sheet.

The methods which have just been described are only examples and the invention is not limited to these. The smart card according to the invention comprises at least one communication interface with the outside and an electronic component opening onto the surface, but it can include other electronic components such as, for example, one or more microphone control buttons. -controller allowing to activate or not the display, a keyboard, or even fingerprint sensors.

In addition, the examples illustrated by FIGS. 1 to 7 and described above all relate to a communication interface comprising an antenna connected to an integrated circuit module, the contacts of which open on the surface of the card, to allow the production of a card. mixed. Of course, the manufacturing method according to the invention also applies to smart cards, the communication interface of which comprises either only an integrated circuit module with flush contacts, to allow operation with contacts; or an antenna connected to an integrated circuit module embedded in the card body, to allow contactless operation.

Where appropriate, in the method of the invention, at least one of the adhesive sheets (12, 22) is not 14

necessarily detached if it is transparent, its attachment to at least one of the components and to one of the plates (11) may become final.

In this case, it has a cover sheet function. Thus, for example for a component which is not intended to have a mechanical interaction with the outside such as a display, the sheet can be transparent. On the other hand, for a component needing to open such as a module 2 contact terminal, the adhesive sheet is removed.

Claims

15 CLAIMS

1. A method of manufacturing a smart card comprising an interface for communication with the outside and at least one electronic component (4) opening onto the surface, characterized in that the electronic component (4) is connected to the communication interface by means of conductive wires (6, 7); the electronic interface - electronic component assembly is temporarily fixed against a first plastic plate (11); a second plate (19; 23) of plastic is placed on the electronic interface - electronic component assembly, an opening (13; 24) being provided either on the first plate (11) or on the second plate (23) to serve housing the electronic component (4); and the two plates (11 and 19; 11 and 23) are secured by enclosing the interface and the electronic component (4).

2. A method of manufacturing a smart card comprising a communication interface with the outside and at least one electronic component (4) opening onto the surface, characterized in that, on a flexible sheet (10) of plastic, conductive tracks (6, 7, 9) for forming a printed circuit; the communication interface and the electronic component (4) are fixed to the printed circuit obtained so that contact pads of the interface are connected to contact pads of the electronic component (4) via the tracks conductive; the electronic circuit board - interface - electronic component assembly is temporarily fixed against a first plastic plate (11); a second plate (19; 23) of plastic is placed on the electronic assembly printed circuit interface - electronic component, an opening (13, -24) being provided either on the first plate (11) or on the second plate (23 ) to serve as housing for the electronic component

(4); and the two plates (11 and 19; 11 and 23) are joined 16

enclosing the electronic circuit board - interface - electronic component assembly.

3. Method according to claim 2, characterized in that a core sheet (20) of plastic material, provided with openings (21) intended to receive the (s) component (s) electronic (s) fixed (s) on the printed circuit, is deposited on the electronic assembly before positioning one of the plates (11, 19; 11, 23).

4. Method according to claim 2, characterized in that the printed circuit (10) produced is a double-sided circuit provided with metallizations on its two faces connected together by conductive vias (30).

5. Method according to one of claims 1 or 2, characterized in that a resin (18) of bonding and sealing is deposited on the electronic assembly prior to the positioning of the second plate (19; 23).

6. Method according to one of claims 1 or 2, characterized in that the temporary fixing of the electronic assembly is done by gluing on the first wafer (11) an adhesive sheet (12) and, in the case where the opening (24) serving as housing for the electronic component (4) is provided on the second plate (23), by bonding to this second plate

(23) another adhesive sheet (22); and in that the electronic component (4) is applied to the adhesive face of the first adhesive sheet (12) inside the opening (13) which serves as its housing, or to the adhesive face of the other adhesive sheet (22) inside the opening (24) which serves as a housing; the adhesive sheet (s) (12, 22) being 17

detached after securing the two plates (11 and 19; 11 and 23).

7. Method according to one of claims 1 or 2, characterized in that the communication interface comprises an integrated circuit module (2) disposed in an opening (14) formed in one (11) of the two plates of so that its contacts are flush with the bottom of the opening, and in that the electronic component (4) is a display which is inserted in its opening (13; 24) so that its display screen is flush with the bottom of the 'opening.

8. Method according to one of claims 1 or 2, characterized in that the communication interface comprises a module (2) of integrated circuit connected to an antenna (5), so as to allow communication without contact with the exterior, and in that the electronic component (4) is a display which is inserted into its opening (13; 24) so that its display screen is flush with the bottom of the opening.

9. Method according to one of claims 1 or 2, characterized in that the smart card is a mixed card, one communication interface comprises a module (2) of integrated circuit connected to an antenna (5); in that the module (2) is inserted into an opening (14) made in one (11) of the plates so that the contacts are flush with the bottom of the opening; and in that the electronic component (4) is a display which is inserted into its opening (13; 24) so that its display screen is flush with the bottom of the opening.

10. Method according to one of claims 7 to 9, characterized in that the display used is a crystal display 18

liquids, or an electrochromic display, or an electrophoretic display.

11. Method according to any one of the preceding claims, characterized in that the plastic plates (11 and 19; 11 and 23) are joined by hot or cold lamination.

12. Method according to one of claims 7 to 11, characterized in that it further consists in transferring a battery (8) and a microcontroller (3) intended to control the display (4), the battery ( 8) being electrically connected to the microcontroller (3), which is also electrically connected to the integrated circuit module (2) and to the display (4).