HK1188505A - Electronic card having an external connector - Google Patents

Description

Electronic card with external connector

Technical Field

The present invention relates to the field of smart cards or electronic cards, in particular bank cards, comprising an electronic unit and/or an antenna incorporated in a card body and an external connector arranged within a cavity of the card body, the external connector having a plurality of contact pads arranged on an external surface forming an insulating support of the connector. The plurality of contact pads are connected to a corresponding plurality of internal contact pads connected to said electronic unit and/or said antenna and visible in the cavity or electrically connected to a plurality of intermediate contact pads visible in the cavity.

Background

Fig. 1A and 1B are schematic diagrams of a conventional industrial process for manufacturing a smart card of the type described above. First, the connector 2 and the card body 12 are manufactured. The card body 12 has a cavity 14 for receiving the connector 2. The connector comprises an outer contact pad 4 arranged on the outer surface of the support 6 and an inner contact pad 8 arranged on the inner surface of the support. The outer liner 4 is electrically connected to the inner liner 8 by means known in the art. The card body 12 includes a plurality of contact pads 16 that need to be connected to the pads 8. The gasket 16 is visible in the horizontal plane of the cavity 14 (parallel to the general plane of the card). Each contact pad 16 is formed of braze (braze) or solder (solder), typically made of tin, deposited on an inner pad 20 of the card body 12. The pad 20 is arranged on the surface of a support 22 associated with an electronic unit and/or an antenna incorporated in the card body 12 and electrically connected to the pad 20 by a circuit.

The film 10 of conductive adhesive and the connector 12 are placed in the cavity 14 of the card body 12, and the adhesive film 10 is arranged between the bottom of the cavity 14 and the connector 2. The connector is secured to the card body 12 using a thermocompression device 26. Figure 2 is a partial view of a card 28 obtained by the prior art method described herein. According to this conventional method, the conductive adhesive 10 forms a layer between the internal contact pad 8 and a contact pad 16, the contact pad 16 being located on a horizontal plane defining the bottom of the cavity 14.

Various tests performed on cards of the type shown in fig. 2 and analysis of defective cards returned by individual users have shown that the electrical connection between the external connector 2 and the contact pads 16 visible in the cavity 14 is unreliable. Electronic cards, particularly bank cards, must be able to withstand various mechanical stresses given that the user typically carries the card in his wallet or in a flexible card holder. The bending and twisting to which the card 28 and its mutually adhered pair of contact pads are subjected will result in local peeling or void formation of the contact pads, which in turn breaks the electrical connection. These electronic cards therefore have a problem of service life.

A smart card comprising an antenna is known from DE patent No. 19732645. The card comprises a recess in which there are two first contact pads, which are electrically connected to the two ends of the antenna, respectively, and an electronic module inserted into the recess. The module also has two second contact pads that are electrically connected to the first two pads. Each of the first pads is defined by a top surface of a truncated metal bump. To establish an electrical connection between the first and second pads, a conductive adhesive or solder or braze is deposited on the first or second pads for soldering or brazing the two pads to each other. The connection obtained by the second alternative is more robust (robust) and electrically improved. However, welding requires a relatively large supply of heat to reach the welding temperature. This document proposes to provide heat by means of an electronic module support, generally formed of an insulating material, which is generally a poor thermal conductor such as reinforced resin or plastic. Supplying a large amount of heat to the support tends to deform the support and even damage the electronic module.

From WO patent No. 97/34247 a smart card of the above-mentioned type is known, in which a solder material provided between contact pads is incorporated in an adhesive film. In particular, the solder material is incorporated in holes made in an adhesive film which is then placed against the electronic module substrate so that the solder is superimposed on the internal contact pads of the module. Finally, the adhesive is activated and heat is supplied through the insulating support of the electronic module to melt the solder. This then presents the same problem as in the previous document. Furthermore, filling the holes of the adhesive film with solder before the film is assembled to the electronic module poses manufacturing problems, since it is not easy to ensure that the solder remains in the holes of the adhesive film until assembled to the electronic module. A variant then proposes to introduce conductive particles into the adhesive film in the region provided for the solder.

This document WO97/34247 also proposes a particular embodiment shown in fig. 2. In this case, the module is provided with first external contact pads which are electrically connected to second contact pads which are flush with the horizontal surface made in the card body via solder-filled channels which are configured through the insulating support of the electronic module and through the first external contact pads. This embodiment presents several problems. First, once the solder melts, it is not guaranteed that the channels are filled with solder. In particular, if the solder introduced into the channel starts in paste form so as to facilitate insertion into the channel, this causes shrinkage of the solder when it melts during assembly and does not ensure a substantial connection (material connection) with the lateral surface of the hole in the external pad, in particular if the thickness of the external pad is relatively small. In turn, the holes made in the external contact pads allow the manufacture of cards that are incompatible with high quality cards and unattractive. This risk appears to have been confirmed by the diagram in fig. 2 of WO patent No. 97/34247, where the solder is located below the level of the top surface of the outer pad. This is therefore a real problem of reliability. Finally, these holes in the outer pads present a problem for card readers that typically have pressure pads (or contact pins) that are easily damaged when a card is inserted into or removed from the card reader. In addition, the solder (e.g., tin) that is melted and solidified is generally much softer than the metal forming the outer pads (copper with bright gold). Thus, if the holes in the external pads are properly filled with solder, the pressure pads and pins of the card reader will spread the solder over the external pads when the card is inserted or removed. This has several negative consequences: first, the reader head is contaminated with solder. Secondly, if the amount of solder spread is relatively large, a short circuit may even occur between two contact pads. Third, the contact pads can also be contaminated by diffused solder, which is unattractive and unacceptable. In either case, it is clear that the diameter of the solder path must be small, so that the hole created in the outer pad is as small as possible to limit the above-mentioned problems. However, with a small solder channel, it is difficult to provide the heat required to form the solder to the second contact pad of the antenna.

Disclosure of Invention

It is an object of the present invention to provide a smart card with an external connector which overcomes the drawbacks of the prior art and provides an efficient soldering or brazing between the external contact pads of the connector and the internal contact pads of the card body.

The invention therefore relates to a smart card comprising:

-an external connector comprising an insulating support defining an external face and an internal face opposite to each other and a plurality of external metal contact pads arranged on the external face of the insulating support;

a card body having a recess in which the external connector is arranged,

-an electronic unit and/or an antenna in the card body, electrically connected to a plurality of internal metal contact pads arranged under the external connector and respectively aligned on the plurality of external metal contact pads in a direction perpendicular to the external face of the insulating support;

a plurality of outer metal contact pads connected to a plurality of inner metal contact pads, respectively, by a plurality of metal parts, each of which is at least partially formed by solder or brazing and passes through the insulating support through a respective hole provided therein;

the smart card is characterized in that the plurality of metal parts are respectively covered by a plurality of external metal contact pads which close holes in the insulating support on the external face of the insulating support. The plurality of metal parts form a connecting bridge between the rear surfaces of the plurality of outer metal contact pads and the plurality of inner metal contact pads, respectively.

In particular, the diameter of the metal part in the hole of the insulating support is large enough to conduct (channel) enough heat through the insulating support to melt the solder material on or under the inner surface of the insulating support when manufacturing the smart card, thereby soldering the connector to the plurality of internal metal contact pads.

According to a general embodiment, the diameter of the metal part in the insulating support hole is greater than 0.2mm (200 μm). According to a preferred variant, the diameter of the metal part in the insulating support hole is greater than 0.5mm (500 μm).

According to a preferred embodiment, the insulating support hole is at least largely filled with solder material.

The invention also relates to an external connector intended to be housed in a cavity of a smart card, the body of which comprises an electronic unit and/or an antenna; the connector includes an insulating support having outer and inner faces opposite one another and a plurality of apertures, and a plurality of outer metal contact pads disposed on the outer face of the insulating support. The connector is characterized in that the plurality of holes are respectively covered by a plurality of external metal contacts which close the holes on the outer surface of the insulating support, and in that the plurality of holes are at least mostly filled with a solder material.

As a result of these features of the smart card according to the invention, in particular the external connector, it is possible, by means of the manufactured robust solder, to achieve an electrical connection between the external connector and the contact pads of the electronic unit and/or of the antenna incorporated in the card body without damaging the electronic unit and without deforming the card body.

Drawings

The invention will be described in the following detailed description, by way of non-limiting example, with reference to the accompanying drawings, in which:

fig. 1A and 1B, already described, are schematic diagrams of a conventional prior art smart card manufacturing method.

Figure 2, already described, is a partial cross-section of a card of the prior art.

Fig. 3 is a schematic illustration of the various elements involved in a first implementation of an advantageous smartcard manufacturing method according to the invention.

Fig. 4A and 4B show two steps of a first implementation of the manufacturing method, respectively.

Fig. 5 is a partial cross-section of a smart card obtained by a first implementation of the manufacturing method.

Fig. 6 shows the steps in a variant of the first implementation of the manufacturing method.

Figure 7 is a partial view of a card obtained by a variant of the method according to figure 6.

Fig. 8A to 8E are schematic diagrams of the various steps of a second implementation of an advantageous smartcard manufacturing method according to the invention.

Figure 9 is a partial cross-section of a card obtained by means of a second implementation of the manufacturing method.

Fig. 10 is a top view of a first embodiment of an external connector according to the invention.

Fig. 11 is a schematic cross section of the external connector in fig. 10 along the line XI-XI.

Fig. 12 is a partial view of a first embodiment of a smart card according to the invention.

Fig. 13 is a partial cross-section of a second embodiment of a smart card according to the invention.

Figure 14 is a partial cross-section of a second embodiment of the connector according to the invention.

Fig. 15 is a partial cross-section of a third embodiment of a smart card according to the invention.

Fig. 16 is a partial cross-section of a fourth embodiment of a smart card according to the invention.

Figure 17 is a partial cross-section of a third embodiment of the connector according to the invention.

Figure 18 is a partial cross-section of a variant of the third smartcard embodiment.

Figure 19 is a partial cross-section of a fourth embodiment of the connector according to the invention.

Figure 20 is a first variant of the fourth connector embodiment.

Figure 21 is a variant of the fourth connector embodiment.

Figure 22 is a second variant of the fourth connector embodiment.

Fig. 23A and 23B show two variants of the third connector embodiment.

Fig. 24A and 24B show two variants of a fifth embodiment of the connector according to the invention.

Fig. 25 is a partial cross-section of a fifth embodiment of a smart card according to the invention.

Fig. 26 is a partial cross-section of a sixth embodiment of a smart card according to the invention.

Detailed Description

With reference to fig. 3, 4A and 4B, a first advantageous implementation according to the invention will be described, formed by a smart card manufacturing method that facilitates the generation of smart cards. The smart card will be described below. Any of the above references will not be described in detail herein. Fig. 3 shows three separate elements involved in the manufacture of a smart card. This is external connector 32, pierced adhesive film 36 and card body 12, which is similar to the body described above.

The external connector 32 comprises a support 6, an external contact pad being arranged on an external face of the support 6. A first plurality of internal contact pads 34 is arranged on the internal surface of the support 6. Gasket 34 is formed by a metal contact having a thickness substantially equal to the thickness of adhesive film 36, for example between 30 and 80 microns (30-80 μm). The hot melt adhesive film has a plurality of apertures 37 arranged to match the first plurality of internal contact pads 34 of the external connector 32. The card body 12 incorporating at least one electronic unit and/or antenna (not shown in the figures) has a cavity 14 provided for the connector 32. A second plurality of contact pads 16 is visible on the surface 15 of the cavity 14, which plurality of contact pads 16 is electrically connected to the electronic unit incorporated in the card body and/or to said antenna.

In one variation, a through adhesive film 36 disposed on surface 15 of cavity 14 is provided for assembling connector 32 to card body 12. Next, external connector 32 is placed in cavity 14 with its inner face 33 abutting adhesive film 36. The first and second pluralities of contact pads 34 and 16 are disposed opposite each other when the connector 32 is inserted into the cavity 14. Adhesive film 36 is substantially cut to the size of cavity 14, which is substantially adjusted to the size of support 6. The holes in adhesive film 36 are made so that they are aligned with the pairs of corresponding contact pads 16 and 34 that are opposite each other. The size of the hole 37 is equal to or slightly larger than the size of the corresponding inner contact pad 34. In this variation, connector 32 and adhesive film 36 are separately placed in cavity 14, and first plurality of contact pads 34 are inserted into apertures 37 of the adhesive film. The internal contact pads 34 then abut against, or are in close proximity to, the contact pads 16 of the card body 12 as a result of the arrangement of the connectors and the adhesive film. Using the thermocompressive device 26, as shown in fig. 4A, the external connector 32 is then bonded to the surface 15 of the cavity 14. Preferably, sufficient pressure is applied to the connector 32 to ensure physical contact between the metal pad 34 and the corresponding pad 16. The cavity 14 then defines a shell of the connector 32, which is adhered to the surface 15 of the cavity by an adhesive 36 located between the surface 15 and the inner face 33 of the connector 32.

In another variation, the adhesive film is disposed on the inner connector surface 33 before the connector is placed in the shell of the card body. In this preparation step, it must be ensured that the adhesive film adheres sufficiently to the connector so that it remains fixed to the connector during processing until the connector is inserted into the housing.

It is to be noted here that in said variant, the adhesive is provided in the form of a hot-melt adhesive film. However, in other variants not described, the adhesive may be provided in other ways, in particular a viscous liquid or paste deposited in a specific area of the surface 15 defined by the inner face 33 of the support 6 or by the bottom of the cavity 14. These latter variants are, however, more complex given that it is not desirable to have the adhesive cover the thicker metal pad 34.

According to a particular variant, the internal contact pads 34 of the connector 32 are constructed by galvanic deposition on the metal pads of the printed circuit on the internal connector face 33. According to another variant, the internal contact pads are realized by screen printing or a similar technique, which deposits the solder material in the form of a paste exactly in a determined thickness corresponding to the thickness of the adhesive film ("solder material" means a metal or metal paste that melts at a temperature suitable for soldering or brazing using a metal material, preferably below 1000 ℃). The connector is advantageously placed in an oven to dry the solder (e.g. tin paste) to harden it, or to melt the paste in a controlled manner to obtain a dense metal internal contact pad (without air and/or additional liquid) after solidification. Finally, in another variant, the internal contact pads 34 are realized in a localized manner in specific areas, in particular on the initial metal pads of the printed circuit, by means of dispensing the solder in doses (dose), in paste or preferably in liquid form (molten metal). In the case of solder paste, the surface of the resulting pad is not necessarily flat. Here again, the connector is advantageously arranged in an oven to dry the paste so that it hardens or melts in a controlled manner. In any case, when the connector is placed in the card body cavity, care is taken that the volume of solder dispensed is substantially equal to the volume defined by the holes made in the adhesive film.

In another variant, not shown, the solder material provided to compensate for the height of the adhesive film is not placed on the internal connector face 33, but on the pads 16 visible in the card body cavity. Also in this case, the amount of the solder material deposited on each pad 16 is determined so that the volume thereof substantially corresponds to or slightly smaller than the volume of the corresponding adhesive film hole 37. When the solder material is provided in the form of a paste, the card body is advantageously placed in an oven to dry the paste so that it hardens or melts in a controlled manner. The height of the contact pads on the inner connector face in this variant is low (e.g. between 5 and 10 microns, which is the conventional height of printed circuits).

In the variant illustrated in fig. 3 and 4A/4B, the second plurality of contact pads 16 is formed by solder 18 deposited on a third plurality of contact pads 20, the third plurality of contact pads 20 being arranged on the surface of a support 22 associated with the electronic unit and/or the antenna and incorporated in the card body 12.

When the external contact pads 34 comprise solder or in the above-described alternative (variant) where solder material is deposited on the pads 16 of the card body 16, the contact pads at the bottom of the cavity 14 may be formed directly by a third plurality of contact pads 20, which then define the pads 16 flush with the cavity surface 15. These pads 20 may have a certain thickness, which may be obtained in particular by means of a relatively thick galvanic deposition. In another variation, each pad 16 may be constructed from a post or metal tongue, for example, comprised of copper, disposed on the printed circuit pad 20.

Once the connector 32 is bonded in the cavity 14 by the thermal press 26, an adhesive 36 surrounds the thick metal pad 34. After the bonding step, these metal pads are arranged against the contact pads 16. As shown in fig. 4B, heat is provided through the connector 32 to solder the first plurality of contact pads 34 to the second plurality of contact pads 16. The soldering can be easily achieved if solder 18 and/or solder at least partially forming thick metal pad 34 is present. The heat for welding is preferably provided locally by a welding hot die 40 of a welding device configured to weld all connections provided simultaneously. This local heat supply is realized to avoid damage to the card body 12, in particular to avoid deformation of the card body.

The above-described manufacturing method results in a smart card 42 which is shown in cross-section in fig. 5. The external contact pads 4 are electrically connected to the thick metal pads 34. The external connector 32 thus allows a card reader having resistive contacts to access the electronic unit incorporated in the card 42. The solder between each internal contact pad of the connector 32 and the corresponding contact pad 20 arranged on the surface of the support 22 ensures a robust electrical connection between the external connector and the electronic unit and/or the antenna contained in the body 12 of the card 42.

Fig. 6 shows a variant of the first embodiment of the method described above, and fig. 7 shows a partial cross-section of a smart card 52 resulting from this variant. Any of the above references will not be described in detail herein. This variant relates to an external connector 44 having an electronic circuit, in particular an integrated circuit 46 coated with a resin 48, on the internal face 33. The external connector 44 thus defines an electronic module of the type used in bank cards with external resistive contacts. In particular, the variant embodiments in fig. 6 and 7 relate to cards known as "dual interface", i.e. smart cards capable of communicating with an electronic contact reader and also communicating with a contactless reader through an antenna arranged in the card body 12A. Thus, for example, the two contact pads 15 visible at the surface 15 in the cavity 14A define the two contact pads of the antenna arranged on the support 22 and incorporated in the card body 12A. The cavity 14A has a bottom recess 50 that is substantially the size of the coating 48 for receiving the integrated circuit 46 and the protective coating 48. As shown in fig. 6 and 7, the recess 50 may pass through the support 22. The internal contact pads 34 of the connector 44 are manufactured in a similar manner as the connector 32 described above.

With reference to fig. 8A to 8E, a second advantageous implementation of the smart card manufacturing method according to the invention for easy production of smart cards will be described below. The smart card will be described below. Any of the above references will not be described in detail herein. In a first step, a pierced adhesive film 36 is placed on the inner face 33 of the external connector 2. The membrane has a plurality of holes 37 corresponding to the plurality of internal contact pads 8 arranged on the internal face 33. Pierced adhesive film 36 has a separable sheet 56 (siliconized paper) that serves as a support for the film. The releasable sheet slightly adheres to the adhesive film 36. Adhesive film 36 is placed on inner face 33 such that inner contact pads 8 are located in corresponding adhesive film holes 37. In the next step, as shown in fig. 8B, adhesive film 36 is applied to inner face 33 using hot press 26 so that adhesive film 36 adheres properly to support 6 of connector 2. The sheet 56 is then removed.

In the following step, schematically illustrated in fig. 8C, solder material 62, in particular a tin paste, is placed in holes 37 of adhesive film 36. The solder slightly overfills the hole and then the excess is removed using knife 64 and the outer surface of solder material 62 is leveled to substantially the level of the outer surface of the adhesive film. In a particular variant, the solder material is dispensed using a device having at least one nozzle. The device deposits an amount of solder material in each aperture that is slightly greater than the volume defined by the aperture. Once diffused into the bonding film pores, the metal paste may be dried in an oven. Since the adhesive film has been applied to the connector care is taken to limit the drying temperature, for example between 50 ℃ and 70 ℃.

Once the solder material has been placed in the holes of adhesive film 36, external connector 60 may be obtained. It comprises a substrate 6 on a first surface of which external contact pads 4 are arranged. A contact pad 8 and a hot melt film 36, the holes of which are aligned with the contact pad 8, are arranged on the second side of the support 6. Solder material 62, and particularly a tin paste, is deposited on contact pads 8 in the holes of adhesive film 36.

In a subsequent step of the second implementation of the manufacturing method, the external connector 60 is placed in the cavity 14 of the card body 66. As with the first embodiment described above, the contact pads 16 formed by the solder material 18 deposited on the internal contact pads 20 of the card body 66 are visible at the bottom surface of the cavity. The above-described variants for manufacturing the contact pads 16 can also be used here. It is to be noted that in all cases the necessary solder material for a suitable soldering is placed in the adhesive film hole. The plurality of contact pads 16 are arranged opposite the plurality of inner contact pads 8 of the connector 60. Solder material 62 deposited in the apertures of adhesive film 36 directly contacts contact pads 62 of card body 66. As shown in fig. 8D, heat press 26 is used to activate the adhesive film to secure connector 60 to card body 66.

Next, the hot press is removed and, in the variant described here, a welding device comprising a plurality of hot dies 40 is used to perform the welding step schematically shown in fig. 8E. It is noted that the heated die 40 is applied to the area of the outer contact pad 4 and is aligned with the corresponding pair of contact pads 8 and 20, respectively, between which the solder materials 18 and 62 are superimposed on each other. Once the connector is secured to the card body, the solder material 62 locally deposited in the adhesive film hole defines an intermediate layer between the two contact pads to compensate for the thickness of the adhesive film 36 between the bottom surface of the card body cavity and the inner face of the connector 60. The heated die 40 locally provides sufficient heat to melt the solder material 62 and preferably at least partially melt the solder material 18 between the corresponding pair of contact pads. After this soldering operation, a smart card shown in cross-section in fig. 9 is obtained.

In the above variant, the external connector is made by hot pressing 26. The internal contact pads of the connector are soldered to the contact pads of the card body in a subsequent step using a specific soldering device. In a variant implementation of the manufacturing method, these two steps are combined by using a device capable of providing the heat necessary to achieve a joint, for example between 100 and 150 ℃, while providing locally on the internal contact pads of the connector sufficient heat to perform the soldering at a temperature of, for example, between 500 and 600 ℃.

The smart card obtained by the second implementation of the manufacturing method is characterized in that the plurality of internal contact pads 8 are connected to the plurality of corresponding contact pads 20 by means of a solder formed by molten solder materials 18 and 62, which merge to form a rigid metal bridge between the pairs of corresponding pads. The solder material is preferably formed of tin; in other variants, however, the soldering can also be carried out with copper.

The card body 66 is formed by an intermediate resin layer 70 located between two outer layers 68 and 69. The support 22 is coated with resin and the contact pads 22 and the braze dots 18 are arranged on the surface of the support. The resin 70 also coats other elements of the manufactured card, in particular the electronic unit and/or the antenna (not shown) incorporated in the smart card. According to a preferred variant, a solid layer 72 is provided on the back of the support 22. The function of layer 72 is to locate the top of support 22 and thus the solder bumps in the middle resin layer. This ensures that the contact pads 16 defined by the truncated solder bumps are flush with the bottom surface of the cavity when the cavity is manufactured. Indeed, it is clear that the depth of the cavity is defined by the thickness of the external connector. When manufacturing is achieved using a resin 70 provided in a non-solid state, in particular a viscous liquid or paste, it is observed that the substrate 22 easily moves down into the resin and then remains relatively close to the solid bottom layer 69. This presents problems with the coating of the individual elements and units provided, particularly for the manufacture of complex cards using non-solid resins. As a result of the additional solid layer 72 provided on the back of the support 22, the support 22 and the solder bumps protruding from the contact pads 20 can be positioned relatively accurately in the thickness of the resin layer.

Within the scope of the present invention, therefore, a method of manufacturing a smart card is provided, which comprises at least one electronic unit and/or antenna and external contact pads incorporated in a card body. The method comprises the following steps:

-manufacturing an external connector having an external contact pad on an external face and a plurality of internal contact pads on an internal face opposite to the external face;

-manufacturing a card body having a cavity for a connector, the electronic unit and/or the antenna being electrically connected to a second plurality of contact pads visible on the surface of the card body cavity;

-placing the connector and the adhesive in a cavity, the first and second plurality of contact pads being arranged opposite each other when the connector is inserted into the cavity;

-supplying heat through the connector to solder the first plurality of contact pads to the second plurality of contact pads, the first plurality of contact pads and/or the second plurality of contact pads being configured and/or solder material being locally deposited on the first and/or second plurality of contact pads to compensate for the thickness of the adhesive between the cavity surface and the inner connector face once the connector is secured to the card body.

Fig. 10 and 11 are schematic views of a first embodiment of an external connector according to the present invention. The connector 78 has an external contact pad 4 on the external face of the support 6 and an internal contact pad 8 on the internal face of the support 6, in a conventional manner. According to the invention, a relatively large diameter metal via 80 is provided between the outer contact pad 4 and the inner contact pad 8. These metal vias are first used for the electrical connection of the outer pad 4 to the inner pad 8. Next, the vias 80, which are superimposed on the internal contact pads 8, facilitate the step of soldering the contact pads to the corresponding card body contact pads as described above. Indeed, the substrate 6 is formed of an insulating material, which is generally a poor thermal conductor. However, the metal vias 80 are very thermally conductive. Heat provided by a particular soldering device as described above is then conducted by the vias 80 to the internal contact pads 8 and to the solder material provided on or under said pads 8 to solder the pads 8 to the internal contact pads of the card body. As a result of the arrangement of the vias 80, as schematically shown in fig. 11, it is thus possible to provide less heat during the soldering step and thus to avoid any local deformation of the card body caused by heat, which heat may generate high temperatures for the plastic or resin constituting the card body.

Fig. 12 shows a schematic cross-section of a first embodiment of a smart card 82 according to the present invention. The card includes a connector 78A according to the present invention, similar to the connector 78 described above and having thick contact pads 34. It is obtained by the first implementation of the above-mentioned manufacturing method. It is noted that each via 80 and associated pad 34 may be made of the same material and thus together form the same element. Figure 13 shows a schematic cross-section of a smart card 82 of a second embodiment of the card according to the invention. The card comprises a connector 78 as described in fig. 10 and 11 and is obtained by the second implementation of the manufacturing method described above. The contact pad 8 may be defined by the bottom surface of the via 80. Thus, in the card of fig. 12 and 13 obtained using the connector according to the first embodiment described above, the plurality of external metal contact pads 4 are connected to the plurality of internal metal contact pads 20 by a plurality of metal parts 18+34+80, 18,62+8+80, respectively, each of which is at least partially formed of a solder material and passes through the insulating support 6 via a hole provided in the insulating support, respectively. The smart card 82, 84 according to the invention is characterized in that the plurality of metal parts are respectively covered by a plurality of external metal contact pads 4 closing the holes on the external surface of the insulating support 6. The plurality of metal parts form a connecting bridge between the rear surfaces of the plurality of outer metal contact pads 4 and the plurality of inner metal contact pads 20, respectively. In addition to the above-described variants for obtaining thick contact pads 34 and for soldering between the internal contact pads of the connector and corresponding contact pads arranged on the surface of the cavity forming the housing for the connector, various advantageous embodiments and specific variants of the invention will be described below.

Fig. 14 shows a second embodiment of a connector according to the invention. The insulating support 6 has a hole 92 closed by the outer metal contact pad 4 on the outer surface 31. Each hole 92 is filled with solder paste 94 to substantially the same level as the inner surface 33 of the insulating support. The solder paste is deposited on the rear surface 5 of the pad 4. The bore has a central axis 96 perpendicular to the outer surface 31 and thus perpendicular to the plane defined by the pad 4. The gasket 4 is preferably formed by a film or sheet of metal, in particular copper, deposited on the outer face 33 of the support 6. The gaskets have a rigidity sufficient to keep them flat on the holes of the insulating support, even when heat is supplied for welding. It is noted that only one or two outer pads are fully shown in fig. 14 and the following figures, but the connector may have several outer contact pads, in particular two rows of three or four pads.

Figure 15 shows a third embodiment of a card 98 according to the invention. The card has a card body 12 of the type described above which includes internal metal contact pads 20 typically disposed on an insulating support 22. The cavity in the card body receives the connector 90 without an adhesive film between the connector and the surface of the cavity. The inner liners 20 are arranged below the outer connectors and are aligned with the outer liners 4, respectively, in a direction 96 perpendicular to the outer faces 31. During manufacture of the card 98, heat is locally supplied to the outer pads 4 to establish the soldered connection, as explained above. The heat is directly transferred to the solder paste 94, which is placed on the rear surface 5 of the outer pad. Using a controlled heat source, the solder material in each hole 92 melts and heat is readily transferred through the solder material to the solder bump 18 that is opposite the corresponding hole 92 and deposited on the inner pad 20. The solder material 18 melts at least at the surface and bonds to the melted solder material 94, which solder material 94 forms a solder 95 after cooling, which solder 95 has a slightly smaller volume due to shrinkage. A small space thus occurs between the solder 95 and the side of the hole 92, as schematically shown in fig. 15. Finally, the card 98 has a plurality of external pads 4 electrically connected to a plurality of internal pads 20, respectively, by a plurality of metal parts 100, each of which is at least partially formed by solder and passes through the insulating support 6 via a respective hole 92 provided on the insulating support. In the illustrated variant, the metal part 100 is entirely formed of a solder material.

Fig. 16 shows a smart card 98A according to a fourth embodiment of the invention. The card differs from that of fig. 15 in that, in addition to being soldered to the card body, the connector is also joined to a surface 15 of the cavity in which the connector is housed. By using a connector as shown in fig. 14, it is apparent that there is a shortage of solder material in the hole 37 of the adhesive film 36 used. However, when the solder material 94 melts, it flows to the solder material 18 and the solder then passes through the holes in the adhesive film. It is noted that other connectors according to the invention described below may be advantageously used.

In all of the figures of the card of the present invention, solder bumps 18 are deposited on the inner pads 20. These projections are internal to the card body and generally have a truncated top surface that initially defines the intermediate contact pad when the cavity is machined. However, the cards of the present invention are not limited to this arrangement. Indeed, in other variants (not shown), each of the internal pads 20 may be flush with the surface of the card body cavity, and the solder may preferably be formed by the solder material contained in the connector below its external pad. It should also be noted that in other manufacturing variations, when the internal pads are visible in the cavity, the solder material may be deposited on the internal pads, or on the solder bumps 18, prior to adding the connector. It will be apparent that the connector holes 92 may be partially filled with solder material or empty when the connector is placed in the cavity. Solder material deposited on the visible pad in the cavity then at least partially fills the insulating support hole. The brazing filler metal is provided in an amount such that the solder material in the hole is in contact with the rear surface of the outer pad 4. The card according to the invention can thus also be obtained after soldering.

Fig. 17 shows a connector 104 according to a third embodiment of the present invention. It differs from the connector of fig. 14 in that the side walls of the holes 92 are coated with a metal layer 106, which adheres properly to the side walls. Layer 106 defines an anchoring layer for the molten solder paste 94. It advantageously comprises a top bright gold, which also preferably covers the rear surface of the external contact pad. Thus, when soldering is performed, the molten solder 95 is easily bonded to the metal layer and the rear face of the external pad. A metal part 100A with air and/or residual adhesive preferably located inside the metal part is thus obtained, as schematically shown in fig. 18, which fig. 18 is a variant of the third embodiment of the card 110 according to the invention.

Fig. 19 shows a connector 114 according to a fourth embodiment. It differs in that the plating 106 extends around the periphery of each hole 92 by a metal layer 107 of the same material. Since the holes 92 are generally circular, the layer 107 generally defines an annular metal liner. Adhesive film 36 is applied to inner face 33 of the insulating support. The adhesive film has holes, each aligned on a corresponding hole of support 6, the diameter of which substantially matches the outer diameter of layer 107. As in the case of the second manufacturing variation described above, the solder material 94 fills not only the holes 92 but also the holes in the adhesive film. Here, excess solder material may be provided and then removed using a blade, as shown in fig. 8C. It is noted that the connectors 90, 104 and 114 as described above may advantageously be placed in an oven to dry the solder paste before the connectors are assembled to the card body. Fig. 20 shows a first variant of providing the solder material 94 using a dispensing device that deposits a precise amount greater than the volume of the hole 92 into each hole 92 of the connector 116, so as to at least partially fill the corresponding hole in the adhesive film and preferably cover the annular contact pad 107 when the connector is inserted into the card body cavity. Note that in this case, the adhesive film may be placed separately from the connector in the corresponding cavity in the card body. Once the connector 114 or 116 is inserted into the cavity and heat is supplied to perform soldering, a card 120 is obtained as exemplarily shown in fig. 21. The card has a metal part 100B between the outer liner 4 and the inner liner 20, i.e. substantially matching the shape defined by the holes 92 and 37 (fig. 20).

Fig. 22 shows a schematic view of a connector 124, which defines a second variant of the connector 114. The connector differs in that the solder material disposed in the holes 92 takes two forms: a first portion 126 in the form of dense metal, i.e., melted and hardened, and a second portion 128 in the form of a paste. In the example shown, the solder paste is first inserted into the hole 92. The connector is then placed in an oven and the paste melts and shrinks so that the solder 126 does not fill the hole 92. Solder paste 128 is then added using screen printing techniques to a sufficient thickness so that the paste reaches at least the outer surface of adhesive film 36. As in the case of fig. 19, when the connector is placed in the housing during manufacture of the card of the invention, it may be advantageous to provide a thickness slightly exceeding that to fill the hole 37 as much as possible and to ensure that there is contact between the solder paste and the contact pad flush with the bottom surface of the housing, even before the solder paste melts.

Fig. 23A, 23B show two variants of the third connector embodiment, respectively. These variations may also be used in the second or fourth embodiment. They differ primarily in that the holes 92 are filled with a solder material 132 in the form of a dense metal, i.e., the solder is melted to fill the holes and then hardens upon cooling. The solder paste may be added and then melted, or a dispensing device may be used to add liquid solder, which then hardens in the hole. The latter case requires more complex equipment. When a solder paste is used, the hole 92 may be filled by two filling steps, in each of which the solder paste is deposited in the hole and then melted. Connector 130 has an aperture 92 filled with solder substantially to the level of internal face 33, while connector 134 has a solder bump 132 with a top surface almost at the level of the outer surface of adhesive film 36. The membrane may be pre-bonded to the interior face 33 of the connector after the solder bumps 132 are formed, or may be placed in the card body cavity prior to or simultaneously with positioning the connector. Solder bumps 132 and 132A define relatively large diameter metal vias. The diameter is greater than 200 microns and preferably more than 500 microns. The height of these projections varies according to the thickness of the insulating support 6, for example between 150 and 250 microns. Unlike conventional electrical vias which have a small diameter (typically on the order of 100 microns or less) or are hollow in their center if the diameter increases, the bumps or vias according to the present invention have a relatively large diameter and are solid because most of the holes in the insulating support are filled with metal.

Fig. 24A and 24B show two variants of a fifth embodiment of a particularly advantageous connector. This embodiment is similar to the fourth embodiment described above, but differs therefrom in that the peripheral metal layer 107A has a relatively large thickness, which is substantially equal to or greater than 30 micrometers (30 μm), for example between 30 and 70 micrometers, and preferably substantially equal to the thickness of the provided adhesive layer. The thin metal layers in fig. 19 and 20 may be vacuum deposited by various techniques known to those skilled in the art. In particular, they may comprise several sublayers to improve the interfacial adhesion function. The thick metal layer may be formed by easily obtaining the desired thickness, preferably by a vacuum deposition method, for example by first depositing at least one thin layer by evaporation and then by galvanic deposition. A final flash of gold may be provided. In this case, the layer 106A covering the sidewalls of the hole 92 is also relatively thick, although it may be thinner. The rear surface of the outer liner forming the hole is also typically covered with the same type of layer. Connector 136 has blind vias defined by metal layers 106A +107A that are substantially filled with solder paste 94 to the level of perimeter layer 107A, while connector 140 has blind vias filled with solder material 132.

Figure 25 shows a fifth embodiment of the card according to the invention. The card 144 is formed by the card body 12 and the connector 140 of fig. 24B. No adhesive film is provided here. Solder fabricated on each of the external pads is used to establish a reliable electrical connection and secure the connector inside the cavity. The metal part 100C is solid and dense throughout. In one variation, the connector 136 of fig. 24A is used. Figure 26 shows a sixth embodiment of the card according to the invention. The card 148 is formed by the card body 12 and the connector 136 in fig. 24A. As explained above, when it melts, the solder paste shrinks slightly, leaving at least one air or cement space in the resulting metal part 100D. In this case, an adhesive layer 36 of substantially the same thickness as the peripheral gasket 107A is arranged between the insulating support and the bottom of the cavity. In one variation, a connector 140 is used.

Finally it is also noted that the technique of the invention for obtaining external contact pads of an external connector soldered to internal contact pads of a card body can also be used to make additional solder joints between the connector and the card body without the need for electrical functions, thereby improving the fixation of the connector to the card body and especially omitting the use of an adhesive film.

Claims (20)

1. A smart card comprises

-an external connector comprising an insulating support defining an external face and an internal face opposite to each other and a plurality of external metal contact pads arranged on said external face of said insulating support;

-a card body having a recess in which the external connector is arranged,

-an electronic unit and/or an antenna incorporated in the card body, electrically connected to a plurality of internal metal contact pads arranged below the external connector and respectively aligned on the plurality of external metal contact pads in a direction perpendicular to the external face;

the plurality of outer metal contact pads are respectively aligned with the plurality of inner metal contact pads by a plurality of metal features, each of the metal features being at least partially formed of solder and passing through the insulating support through a respective hole provided therein;

said smart card being characterized in that said plurality of metal parts are respectively covered by said plurality of external metal contact pads closing the holes on said external face of said insulating support, said plurality of metal parts respectively forming a connection bridge between said rear surface of said plurality of external metal contact pads and said plurality of internal metal contact pads.

2. The smart card of claim 1 wherein the diameter of the metal component in the insulating support hole is large enough to direct sufficient heat through the insulating support when the smart card is manufactured to melt solder material on or below the inner surface of the insulating support and thereby solder the connector to the plurality of internal metal contact pads.

3. Smart card according to claim 1, characterized in that said metal component has a diameter greater than 0.2mm (200 μ ι η) in said hole of said insulating support.

4. Smart card according to claim 1, characterized in that said metal component has a diameter greater than 0.5mm (500 μ ι η) in said hole of said insulating support.

5. Smart card according to any of the previous claims, characterised in that said insulating support hole is at least mostly filled with said solder material.

6. The smart card of claim 5, wherein the hole is substantially completely filled with a metal, a majority of the metal being formed from a solder material.

7. The smart card of claim 5 or 6, wherein the side walls of the insulating support hole are covered by a metal layer forming an adhesive interface for the solder material located in the hole.

8. The smart card of claim 7, characterized in that a peripheral metal gasket surrounding said hole in said insulating support is arranged on said inner face of said insulating support.

9. Smart card according to any one of the preceding claims, characterized in that an adhesive film is arranged between the internal face of the insulating support and the surface of the shell opposite the internal face, the adhesive film having holes respectively aligned with the holes in the insulating support.

10. External connector intended to be housed in a cavity of a smart card containing an electronic unit and/or an antenna within a card body, the connector comprising an insulating support having an external face and an internal face opposite to each other and a plurality of holes for external metallic contacts, arranged on the external face of the insulating support, characterized in that said plurality of holes are respectively covered by said plurality of external metallic contacts closing said holes on the side of the external face of the insulating support, and in that said plurality of holes are at least mostly filled with a solder material.

11. The connector of claim 10, wherein the plurality of holes are substantially completely filled with metal, at least a majority of the metal being formed from a solder material.

12. Connector according to claim 10 or 11, characterized in that the solder material is at least partly in the form of a paste.

13. The connector of any of claims 10 to 12, wherein the solder material is formed at least in part from solid metal.

14. The connector according to any one of claims 10 to 13, characterized in that the side walls of the holes in the insulating support are covered by a metal film forming an adhesive interface of the solder material located in the holes.

15. The connector according to any one of claims 10 to 14, characterized in that it has perimeter metal pads, each of which surrounds the plurality of holes in the insulating support.

16. The connector of claim 15, wherein the peripheral metal pad has a thickness substantially equal to or greater than 30 microns (30 μm).

17. A connector according to any one of claims 10 to 16, characterised in that an adhesive film is applied to the internal face of the insulating support, the adhesive film having apertures substantially aligned with the apertures in the insulating support.

18. The connector of claim 17, wherein the diameter of the holes in the adhesive film is greater than the diameter of the plurality of holes in the insulating support.

19. Connector according to claim 17 or 18, characterized in that the solder material fills the plurality of holes in the insulating support and has an excess amount in each hole that substantially matches or is smaller than the volume of the corresponding hole in the adhesive film.

20. The connector of claim 15 and any one of claims 17 to 19, wherein the peripheral metal gasket has a thickness substantially equal to the thickness of the adhesive film.