Method for the production of an electronic module for a chip card with a security pattern

Abstract

The invention relates to a method for producing security patterns (11, 12) on an electronic module (10) for security credentials, comprising the following steps: - providing a dielectric film (1); - producing a through hole (2) in the dielectric film (1); - depositing at least one metal layer (3) on the upper and lower surfaces of the dielectric film (1), leaving said hole (2) open; - defining, by etching, on the one hand a set of functional metal areas (4, 14) comprising a central area (14) forming an electrical ground and a set of electrical contacts (4) separated from the electrical ground and from each other by non-metalized areas of the dielectric film (1) and, on the other hand, a set of non-functional or decorative areas (15); - characterized in that it comprises the following step: producing simultaneously, by etching operation, a first security pattern (11) in relief and a second security pattern (12) in embossing, the first security pattern (11) in relief being obtained by removing material in one of said functional metal areas (4, 14), the second security pattern (12) in embossing being raised with respect to the dielectric film (1) and being obtained by removing material in areas located outside of said functional metal areas (4, 14) of the electrical contacts (4, 14) forming terminal blocks.

Description

Technical Field

[0001] This invention relates to microelectronic modules, particularly microelectronic modules for chip cards, having a metal contact terminal block (bornier) on one side. This can relate to modules for contact chip cards in the ISO 7816-1 format, or modules for hybrid chip cards that include an antenna and operate both in a contact mode with a contact reader and a contactless mode with a remote reader. As a non-limiting example, the invention is particularly applicable to electronic modules for identification cards including security markings.

[0002] However, this invention is not dependent on the size of the carrier, and the module can be used for both conventional chip cards and other protected credentials with contact electronic modules, such as electronic passports. Therefore, for the sake of simplicity, the term "chip card" is used to refer to common chip cards (according to ISO 7816-1 standard) as well as security credentials with other formats but also with electronic modules commonly used in the aforementioned chip cards. Background Technology

[0003] Several types of chip cards are known in the prior art, which have a security pattern (motif de sécurité) on the card body or the surface of the card's electronic module.

[0004] For years, there has been a desire to provide contact identity chip cards with a secure pattern covering the top surface of the card body that can detect or limit fraud. However, it has been found that generating such a secure pattern on the module itself is not easy because the conductivity of the module's contacts may be compromised.

[0005] To partially address this issue, document DE-196 25 466 C1 describes a chip card that operates by contacting corresponding contacts of a reader. The contacts themselves are patterned, specifically in a unique color different from the common gold or silver. For this purpose, the contacts are covered with a metallic dispersion layer containing aluminum-based colored particles. However, the contacts remain electrically accessible, meaning that fraudulent attacks on the chip circuitry via the chip card's contacts are still possible. Furthermore, both the contacts and the module remain physically accessible and are fairly easily portable using current technology, making it conceivable to remove and replace the electronic module.

[0006] The document US 6 259 035 B1 also describes a contact chip card that attempts to make the electronic module and metal contacts as inconspicuous as possible by coloring the contacts themselves and by making the graphics on the module surface an extension of the card body graphics.

[0007] In contrast, document US 5,552,574 seeks a different approach, which describes how to provide a security pattern generated by laser beams for the surface of the contact portion of a contact chip card.

[0008] As can be seen from the previous examples, the solution to the security marking problem of contact cards is either to generate a grid pattern or other graphics on the card body, or to change the graphics of the metal contact part of the module, either in the form of color or by directly laser etching on the contact part.

[0009] A method for creating a decorative entity on a chip card is also known from document FR 2 777 506 A1, comprising contact pads located on an electronic module and pads of any shape complementary to the contact pads of the module to form the decorative entity. Therefore, this method is intended for decorative purposes only, and not for protecting the chip card against fraud.

[0010] In the field of combating fraud, a method is known from document EP 2 350 929 A1, which involves creating multiple through holes through the card body and module, thereby making it more difficult to remove the card and reassemble it with a counterfeit card body or module.

[0011] Following the same concept, document WO 2005 / 027020 A1 describes a module for chip cards whose connectors include one or more micro-holes invisible to the naked eye but observable at sufficiently high magnification. This implies specific manipulations incompatible with fast transactions. Furthermore, the micro-holes being located in functional areas of the connectors pose a risk of interference with chip card readers.

[0012] Document EP 2 533 175 A1 describes a chip card whose module includes a printed image in addition to electrical contacts. The printed image can be partially printed on the module and partially printed on the card body to facilitate the detection of fraud such as module removal.

[0013] To manufacture chip cards, reliable and high-volume manufacturing methods are generally preferred, such as the traditional embedding method used for contact cards, which involves placing the contact module within a cavity in the card body. However, this method itself has low security because cards manufactured in this way are particularly vulnerable to fraud such as removing the module from the card, which is especially dangerous for cards or credentials intended for identity verification applications.

[0014] Purpose of the invention Therefore, the object of the present invention is to provide an electronic module structure for chip cards or other security credentials that can overcome the above-mentioned disadvantages, as well as a method for producing such a module.

[0015] In particular, the object of the present invention is to provide a method for producing a module for a chip card and a module thus obtained for use in identity verification applications, which is more secure, easier for official manufacturers to produce, and has high yield and low cost.

[0016] Another object of the present invention is to enable the generation of security graphics, such as logos or other security patterns, directly on the visible surface of the module, thereby making it more difficult to modify or replace the electronic module in the event of an attempt to defraud. Summary of the Invention

[0017] Therefore, the subject of this invention is a method for generating a security pattern on an electronic module used for security credentials, comprising the following steps: - Provide dielectric film; - Creates through-holes in the dielectric film; - Deposit at least one metal layer on the upper and lower surfaces of the dielectric film, leaving the pores open; - By etching, a set of functional metal regions on one side and a set of non-functional or decorative regions on the other side are defined. The set of functional metal regions includes a central region forming an electrical ground and a set of electrical contacts that are separated from and from the electrical ground by non-metallized regions exposing the dielectric film. - The method is characterized by the following steps: simultaneously generating a recessed first security pattern and a raised second security pattern by an etching operation, wherein the recessed first security pattern is obtained by removing material from one of the functional metal regions, and the raised second security pattern protrudes relative to the dielectric film and is obtained by removing material from the region outside the functional metal region where the electrical contact of the terminal block is formed.

[0018] According to one embodiment of the method, the first safety pattern is generated in the central region forming an electrical ground.

[0019] According to one embodiment of the method, the first security pattern is generated by performing photochemical etching to remove the at least one metal layer so that the outline of the first security pattern is recessed and exposed on the dielectric film.

[0020] According to one embodiment of the method, the second security pattern is obtained by performing photochemical etching to locally remove the at least one metal layer so that the outline of the second security pattern is exposed raised on a dielectric film outside the functional region.

[0021] According to one embodiment, the method according to the invention includes the additional step of electrolytically depositing at least one additional metal layer of silver, gold, nickel or palladium.

[0022] The present invention also relates to an electronic module for a chip card, comprising a dielectric film having a microelectronic chip disposed on its lower surface, the input / output terminals of which are connected to metal contact pads via wires, and the dielectric film having at least one metal layer on its upper surface including a set of functional metal regions forming an electrical contact terminal block separated by non-metallized regions exposed in the dielectric film, the metal contact pads on the lower surface being electrically connected to the electrical contacts of the terminal block through holes in the dielectric film, and the electronic module including a first security pattern recessed in one of the functional metal regions and a second security pattern protruding relative to the dielectric film and located outside the functional metal regions forming the electrical contacts of the terminal block, characterized in that the first security pattern and the second security pattern are obtained using the method described above.

[0023] According to one actual embodiment of the module, the electrical contacts of the terminal block are standardized contacts conforming to ISO 7816.

[0024] According to one embodiment of the module, the first safety pattern is located in the central metal region of the terminal block corresponding to the electrical ground of the module.

[0025] Advantageously, the first and second safety patterns of the module have the same shape, but can have two different proportions.

[0026] As a variant, the first and second safety patterns of the module present two complementary shapes, which can form a composite safety element by juxtaposing the first and second safety elements.

[0027] According to one embodiment of the module, two security patterns present complementary alphanumeric characters, which together form a unique security code or expression.

[0028] According to one embodiment of the module, the two security patterns are two different parts of an image or sign, such that the juxtaposition of the two graphic security elements enables the reconstruction of the complete image or sign.

[0029] The subject of this invention also includes chip cards or security credentials comprising the innovative modules and carriers described above. Attached Figure Description

[0030] Other features and advantages of the invention will become apparent from reading the detailed description and accompanying drawings, wherein: - Figure 1A and 1B Cross-sectional and plan views of a module for a contact chip card are shown, respectively, with the visible surface of the chip card including at least two graphic security elements according to the invention; - Figures 2A to 2D Cross-sectional and plan views of a module for a chip card at different stages of the module manufacturing method according to the present invention are shown. Detailed Implementation

[0031] Refer to Figure 1. In this figure, in Figure 1A Cross-sectional diagram of China and Israel and in Figure 1B The diagram shows an electronic module 10 according to the present invention. It includes a dielectric film 1 with a microelectronic chip 8 disposed on its lower surface, protected by encapsulating resin 9. Input / output terminals of the microelectronic chip 8 are connected to metal contact pads 6 via wires 7. The dielectric film 1 includes at least one metal layer on its upper surface, having a set of metal regions forming terminal blocks of electrical contacts 4, 14, separated by non-metallized regions 13, which partially expose the upper surface of the dielectric film 1. In the case of a module for a chip card, the electrical contacts 4, 14 of the terminal blocks are, for example, standardized contacts according to ISO 7816.

[0032] The contact pads 6 on the lower surface of the module are connected to the electrical contacts 4 and 14 of the terminal block through conductive holes 2, such as through-holes passing through both sides of the dielectric film 1. This electronic module structure is known in itself. It allows the module 10 to be placed into the cavity of a carrier such as a chip card body, exposing the upper surface of the module that carries the contacts 4 and 14.

[0033] To enhance the security of the final product, it is known to mark the upper surface with security markings proving its origin, for example, by etching in the central metal region 14. This corresponds to slightly removing metal material to reveal the logo or shape of the manufacturer or issuer of the chip card corresponding to the carrier module. The resulting marking corresponds to a recessed pattern in the contact area of ​​the terminal block, typically in the central region 14 of the terminal block corresponding to the electrical ground of the module.

[0034] However, obtaining fraudulent modules using currently available tools for retroactively forging such markings remains quite easy. Fraud is typically carried out via laser etching, but lasers cannot add patterns by adding material.

[0035] To address this problem, the present invention proposes to generate a second graphic security pattern on the module surface, outside the areas of the electrical contacts 4, 14, i.e., in the non-functional areas comprising non-functional but purely decorative metal elements 15. These metal elements 15 are interconnected with each other and interconnected with the module's electrical ground 14. They consist of other metal elements that protrude relative to the surface of the dielectric film 1. Therefore, the present invention proposes to use one or more of these decorative metal elements 15 to generate a second graphic security pattern 12 that protrudes relative to the surface of the dielectric film 1.

[0036] Several options exist for understanding, through simple visual inspection, that it is a second security pattern 12 complementary to the first security pattern 11. For this purpose, it is sufficient that the raised shape of the second security pattern 12 is the same as or complementary to the shape of the first security pattern 11 by a certain scaling factor. Thus, it can be a symbol, alphanumeric symbols, or any other distinctive image.

[0037] As one embodiment, the first security pattern 11 and the second security pattern 12 may present two complementary shapes capable of forming a composite security element by juxtaposing the first and second security elements. In particular, it may be complementary alphanumeric characters that together form a unique security code or expression.

[0038] As a variation, the two security patterns 11, 12 can be two different parts of an image or sign, so that the juxtaposition of the two graphic security elements 11, 12 allows for the reconstruction of the complete image or sign.

[0039] If the available space around the contact portions 4, 14 of the module allows it to generate two or more second safety patterns 12, these two or more second safety patterns 12 are complementary to the first safety pattern 11 arranged at the center of the module.

[0040] The increased security achieved by this invention lies in the fact that a second security pattern 12 is formed in a single manufacturing module, protruding relative to the dielectric film 1. It is very difficult to subsequently reproduce such a security pattern 12 in the region 13 pre-etched on the periphery of the module and expose the dielectric film, because it is very difficult or even impossible to locally add a second security pattern of metal by lamination, while the entire metal surface of the module is usually obtained in a single electrolytic deposition operation followed by an electrochemical etching operation.

[0041] The method according to the invention enabling the acquisition of security patterns 11, 12 on electronic module 10 will now be described in more detail with reference to FIG2. Steps known per se related to the placement and connection of chip 8 will not be described.

[0042] like Figure 2A As shown, starting with the provision of dielectric film 1, through-hole 2 is formed in dielectric film 1, and the through-hole 2 will be metallized to form a through hole that electrically connects the two sides of the future module.

[0043] Then, as Figure 2B As shown, a first metal layer 3 is deposited on the upper and lower surfaces of the dielectric film 1, leaving the hole 2 open. This is typically achieved by electrolytic deposition on both sides of the dielectric film, usually copper.

[0044] The metal surfaces are then photochemically etched to define contacts 4, 14, and 6 on the surface of the module. On the upper surface, metal material is removed to define regions 4, 14, and 15 that retain metallization, and region 13 exposing the upper surface of the dielectric film 1. The retained metal regions define the functional contact regions 4 and 14 according to ISO 7816, namely the five contacts 4 and the central grounded region 14, as well as the remaining purely decorative metal regions 15 without any special function. Due to the electrochemical etching, the various functional electrical contacts 4 and 14 are de-circuited from each other. The decorative metal regions 15 are generally connected to each other and to the central grounded region 14.

[0045] like Figure 2C As shown, the method according to the invention includes the following steps: using electrochemical etching to produce an engraved first security pattern 11 by removing material from one of the functional metal regions 4, 14, and producing a second security pattern 12, the second security pattern 12 being a raised metal residue located outside the functional metal regions 4, 14 forming the electrical contact portion of the terminal block.

[0046] According to one embodiment shown, a first security pattern 11 is formed in a central region 14 forming an electrical ground. This first security pattern 11 is etched, in particular, by photochemical methods to remove material from the metal layer down to the dielectric film 1, so that the outline of the first security pattern 11 is recessed and exposed on the dielectric film, in the illustrated example, as an image of a salamander.

[0047] Simultaneously, the second security pattern 12 is etched by removing metal from the non-functional area 13 surrounding the ISO contact portions 4 and 14, so that the outline of the second security pattern 12 is exposed raised on the dielectric film 1, outside the functional areas 4 and 14.

[0048] Therefore, these etching operations can be performed simultaneously in a highly efficient manner, making it extremely difficult, if not impossible, to retroactively create a second pattern 12 by adding material in the event of an attempt to defraud. Thus, the same etching operation produces a recessed shape 11 at the center of the module and a raised shape 12 on the periphery of the module. The correspondence between the two patterns 11 and 12 thus obtained is chosen as proof that these two patterns are graphic security patterns produced by the official module manufacturer.

[0049] like Figure 2D As shown, additional metal layers can be added afterward on the remaining first copper layer to increase the mechanical strength of the ISO contacts, increase their conductivity, or simply improve their appearance.

[0050] Therefore, one or more layers of silver, gold, nickel, or palladium can be added by electrolytic deposition. Electrolytic deposition allows for the covering of only the copper areas remaining after etching (including the second security pattern) without affecting the areas exposed on the surface of the pre-etched dielectric film 1.

[0051] Advantages of the present invention This invention achieves the intended purpose and proposes a new method for producing contact or hybrid contact and non-contact electronic modules, which have at least two complementary safety patterns. Such production is only possible under favorable economic and technical conditions during the industrial manufacturing phase of the module.

[0052] Within the framework of this method, two safety patterns are generated simultaneously: one is recessed in the metal contact area, and the other is raised outside the area. The manufacturing method according to the invention enables the modules to be mass-produced on a production line very simply and economically, whereas such production is extremely difficult to do manually afterwards.

[0053] The increased security achievable by this invention stems from the fact that the first security pattern is recessed relative to the metal layer, while the second pattern is raised relative to the dielectric. However, it is extremely difficult, if not impossible, to commit fraud by retroactively adding a raised second pattern to a dielectric that initially did not contain any protrusions. This is impossible for laser processes commonly used by fraudsters, as lasers can only remove material, not add it. Furthermore, methods that retroactively add a second pattern by locally attaching several metal layers to the dielectric region will hardly achieve the same results as this invention.

[0054] Therefore, the modules and methods according to the invention enable significantly enhanced resistance to fraud against these modules and the chip cards carrying them.

[0055] Furthermore, because the graphic security elements are generated on the visible surface of the electronic module, the module becomes particularly easy to use and verify through simple visual inspection with the naked eye.

Claims

1. A method for generating security patterns (11, 12) on an electronic module (10) used for security credentials, comprising the following steps: - Provide dielectric film (1); - Create a via (2) in the dielectric film (1); - Deposit at least one metal layer (3) on the upper and lower surfaces of the dielectric film (1) while leaving the hole (2) open; - By etching, a set of functional metal regions (4, 14) on one side and a set of non-functional or decorative regions (15) on the other side are defined. The set of functional metal regions (4, 14) includes a central metal region (14) forming an electrical ground and a set of electrical contacts (4) that are separated from and from the electrical ground by non-metallized regions exposing the dielectric film (1). - The method is characterized by the following steps: simultaneously generating a recessed first security pattern (11) and a raised second security pattern (12) by an etching operation, wherein the recessed first security pattern (11) is obtained by removing material from one of the functional metal regions (4, 14), and the raised second security pattern (12) protrudes relative to the dielectric film (1) and is obtained by removing material from the region outside the functional metal regions (4, 14) of the electrical contact portion (4) forming the terminal block.

2. The method according to claim 1, characterized in that, The first safety pattern (11) is generated in the central metal region (14) that forms an electrical ground.

3. The method according to claim 1 or claim 2, characterized in that, The first security pattern (11) is generated by performing photochemical etching to remove at least one metal layer so that the outline of the first security pattern (11) is recessed on the dielectric film (1).

4. The method according to claim 1 or claim 2, characterized in that, The second security pattern (12) is obtained by performing photochemical etching to locally remove the at least one metal layer so that the outline of the second security pattern (12) is exposed on the dielectric film (1) outside the functional metal regions (4, 14).

5. The method according to claim 1 or claim 2, characterized in that, It includes the additional step of electrolytically depositing at least one additional metal layer of silver, gold, nickel or palladium.

6. An electronic module (10) for a chip card, comprising a dielectric film (1) having a microelectronic chip (8) disposed on its lower surface, the input / output terminals of which are connected to a metal contact pad (6) via wires (7), and the dielectric film (1) comprising at least one metal layer on its upper surface, comprising a set of functional metal regions (4, 14) forming an electrical contact terminal block, which are separated by non-metallized regions exposing the dielectric film (1), the metal contact pad (6) on the lower surface being electrically connected to an electrical contact portion (4) of the terminal block through a hole (2) in the dielectric film (1), and the electronic module (10) comprising a first security pattern (11) recessed in one of the functional metal regions (4, 14) and a second security pattern (12) protruding relative to the dielectric film (1) and located outside the functional metal regions (4, 14) forming the electrical contact portion of the terminal block, characterized in that, The first security pattern (11) and the second security pattern (12) are obtained using the method according to any one of claims 1 to 5.

7. The electronic module (10) according to claim 6, characterized in that, The two safety patterns (11, 12) have the same shape.

8. The electronic module (10) according to claim 7, characterized in that, The two safety patterns (11, 12) are presented in two different proportions, showing the same shape.

9. The electronic module according to any one of claims 6 to 8, characterized in that, The first safety pattern (11) is located in the central metal area (14) of the terminal block corresponding to the electrical ground of the module.

10. The electronic module according to claim 6, characterized in that, The first security pattern (11) and the second security pattern (12) present two complementary shapes, which can form a composite security element by juxtaposing the first security pattern (11) and the second security pattern (12).

11. The electronic module according to claim 10, characterized in that, The two security patterns (11, 12) present complementary alphanumeric characters, which together form a unique security code or expression.

12. The electronic module according to any one of claims 10 or 11, characterized in that, The two security patterns (11, 12) are two different parts of an image or sign, so that the juxtaposition of the two graphic security elements (11, 12) allows the complete image or sign to be reconstructed.

13. A chip card, characterized in that, It includes the electronic module (10) according to any one of claims 6 to 12.

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