FR2812224A1 - Integrated electronic circuit silicon layer placement having sub layer deposited then silicon substrate barrier layer screen print deposited. - Google Patents

Abstract

The deposition process of a barrier layer of silicon on a substrate uses screen print deposition. Before depositing the silicon layer a sub level is deposited.

Description

PROCESS FOR CONTINUOUSLY DEPOSITING A LAYER OR BARRIER

  OF SILICONE ON A SUBSTRATE AND PLANT FOR THE IMPLEMENTATION

WORK OF THIS PROCESS.

  The invention relates to a method for enabling the establishment of a silicone layer or barrier at the level of a substrate. It relates more particularly to the field of integrated electronic circuits, more commonly known as electronic chips.

  It also relates to the installation capable of implementing such a method.

  Given the physical and chemical characteristics of silicones, in particular their hydrophobic character, their insensitivity to water vapor, their non-stick character as well as their dielectric properties, they are the subject of

  many applications that are only developing.

  However, their implementation is not always easy, taking into account precisely their

non-stick character.

  The objective of the present invention lies in the use of the dielectric properties of silicones while overcoming the drawbacks linked to its non-stick character. Among the objectives targeted by the present invention, one of them consists in: put in place a layer of silicone, acting as both a physical barrier and

  electric, automatically, repeatedly, and continuously.

  This process for continuously depositing a layer of silicone on an insulating substrate

  electrically characterized in that it consists in carrying out this deposition by screen printing.

  According to an advantageous characteristic, the silicone is polymerized after deposition.

  It is even advantageously prepolymerized during deposition, the substrate being at this

slightly heated effect.

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  According to another advantageous characteristic of the invention, the deposition of the silicone layer is carried out, the deposition of an underlying layer, incorporating a hardener, also undergoing a polymerization step

  prior to the deposition of the silicone layer.

  This underlying layer, typically consisting of an ink, is intended for

  promote the adhesion of the silicone to the substrate.

  The invention also relates to the implementation of this particular method in the context of the production of protective barriers for the connection pads of integrated electronic circuits, also called chips, during the pouring of the resin to the

  support level incorporating such integrated electronic circuits.

  To do this, the integrated circuit supports, prior to their installation at the level of the final support cards, receive at their periphery a barrier of

  silicone deposited by screen printing.

  Advantageously, the establishment of this layer of silicone is preceded by the deposition of an underlying layer of an ink incorporating a hardener, the assembly being

  polymerized to promote adhesion of the silicone at this level.

  Finally, the invention relates to the installation for the implementation of this method.

  The manner in which the invention can be implemented and the advantages which result therefrom will emerge more clearly from the example of embodiment which follows, given by way of indication and not

  limiting in support of the appended figures.

  Figure 1 is a schematic view of the installation according to the invention.

  Figure 2 is a schematic plan view of a carrier strip of

  electronic micro-modules after installation of the silicone barrier.

  Figure 3 is a schematic sectional view of part of a card incorporating the

  micro-module according to the invention.

  The following description is more particularly directed towards the implementation of

  the invention in connection with integrated electrical circuits. However, it is understood that the invention remains applicable in other technical fields than this.

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  Has been described in connection with Figure 1, an installation implementing the method

according to the invention.

  In this case, a micromodule has been described intended to integrate at least one integrated electronic chip or circuit, and which must be implemented within a card conventionally called a smart card. Traditionally, such cards include an insulating substrate, adhering on at least one of its surfaces to the tracks

conductive of a printed circuit.

  These cards are conventionally of composite structure comprising a central layer, the latter generally consisting of a dielectric material, such as a resin.

  thermosetting reinforced with glass fibers.

  Such a smart card therefore comprises a support made of plastic, constituting the card itself, in which a micromodule is integrated, comprising the chip or the integrated circuit itself, a connector with several

  contacts and connecting wires between the chip and the connector.

  The smart card connector is made up of the micromodule connector.

  Traditionally, these micromodules are produced on support strips comprising two parallel rows of such micromodules. On one of the faces of the support strip (30) appear the various contactors of the micromodule (32), intended to be connected to the chip proper. The number of contactors (35) is traditionally fixed at 8, according to ISO 7816, but can be limited to only five or six. The other side of the micromodule has the contact surfaces for

  allow the reader to read the card in use.

  FIG. 2 shows a plan view of this support strip on

  which shows the face provided with contactors (35) of each of the micromodules (32).

  This strip (30), made of a rigid material, and for example a glass fiber substrate, is provided at its periphery with perforations (31), intended to allow the cooperation of the latter with a toothed wheel, and therefore of ensuring its linear progression, and on the other hand, ensuring the indexing of the progression of said strip, during the various stages of the implementation of the method according to the invention, and

  including the installation of a silicone barrier.

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  FIG. 3 also shows a cross-sectional view of part of a smart card. Thus, the micromodule appears with the reference (32), at the level of

  one of the outer faces (33) of said card.

  This micromodule (32) comprises on one of its faces (34) the contactor intended to cooperate with the appropriate members of the card reader, and on its other face, the contactors (35) constituted by different pads which are observed also in FIG. 2. The method of placing the silicone barrier according to the invention will be described in more detail, according to the preferred advantageous form of the invention. This

  installation is also described in relation to FIG. 1.

  The strip (30) comprising the micromodules (32) is stored on a reel,

  advantageously moved in rotation by an electric motor (not shown).

  As a corollary, as it unfolds, a protective intermediate strip (8) interposed between the successive turns of the strip (30) on the reel (7) is wound on a reel (6), also moved rotation by a motor

electric not shown.

  This strip (30) is supported by pliers or toothed wheels, not shown, in order to provide it with step-by-step progression at the level of the first step (1) of the method according to the invention, consisting in putting in place level of the periphery of the connection pads (35), a first layer of limited width of an ink advantageously incorporating a hardener. As an example, one can use a pad printing ink. This ink is deposited by screen printing on a table (10) by a traditional process, using a screen printing screen (11), comprising a selected screen.

  depending on the degree of viscosity of the ink, as well as a doctor blade (12) and a counter

doctor blade (13).

  Advantageously, and with a view to optimizing the yield of the process, the establishment of this first peripheral layer is carried out at the rate of a series of eight micromodules, distributed in two rows of four. The installation therefore comprises for this purpose, two doctor blades and two counter doctor blades operating in synchronism with one another.

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  A check is advantageously carried out by the operator at the end of this phase (1) at

by means of a magnifying lamp (14).

  Then, at phase (2), the ink thus set up by screen printing is polymerized by means of an oven (15), heated to the appropriate temperature, typically higher than 100 C. Advantageously and in order to gain time over the duration of this polymerization, the strip (30) is already heated at the level of phase (1), that is to say, when the ink is deposited on the strip, this heating s' performing by contact

with the table (10).

  The condition of the ink after the polymerization phase (2) is possibly checked with

  by means of a lamp (16) and a binocular magnifier (17) by said operator.

  The strip (30) is conveyed to a variable storage store (18), of a type known per se, and typically comes to wrap around a roller (9) capable of moving vertically, depending on the tension exerted on it. The band

  continues its progression at the level of a phase (3).

  At this level, each of the micromodules (32) receives on the ink layer deposited during the previous step, an additional layer of silicone (37), also put in place by screen printing. For this purpose, there is also a screen printing screen (19) of mesh defined as a function of the viscosity of the silicone used. This screen is associated with two doctor blades (20) and two counter doctor blades (21), proceeding as when depositing the ink layer, with the simultaneous placement of silicone at two parallel rows of four micromodules, and this, in order to optimize the

  production yield of this silicone layer.

  The indexing of the strip (30) at the level of the table (29) at which the deposition of the silicone layer is carried out, is such that perfect centering of the upper layer (37) of silicone is achieved. level of the ink layer (36). This indexing is carried out, as already specified by means of perforations (31) formed at the two edges of the strip (30). These different centers are checked by a

  optical system (22), (24) and (25), like the optical system (14), (16) and (17).

  As during the ink deposition, the strip (30) is advantageously preheated at the level of the table (29), so as to favor the polymerization of the silicone during

  the subsequent step (4) in an oven (23).

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  At the outlet of the oven (23), the strip is then stored on a reel (27) with the installation of an intermediate protective film (28), the respective tension of the strip (30) and of the film (28) at the level of these two coils being produced by means of counterweights

  and references (26) of a type known per se.

  We obtain in this way, by a relatively simple process consisting of screen printing the establishment of a silicone barrier (37) capable of protecting the connection pads (35). In fact, and in a known manner, the chips are only placed at the level of the micromodules, generally by automatic process, after

  spacing of the latter within the constituent substrate of the card itself.

  In this way, taking into account the joining of said micromodules to the substrate by casting of resin, prior to the placement of the chip, it is necessary to protect the connection pads (35) of the resin. This protection is achieved by the

  aforementioned silicone barrier, and this, quite advantageously.

  This process is relatively simple, and allows very precise deposition of a dielectric material on a determined substrate at high rates, which is not the case.

  knew how to do effectively to date.

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Claims (14)

  1. A method for continuously depositing a layer of silicone on an electrically insulating substrate, characterized in that it consists in carrying out this deposition by screen printing. 2. Method according to claim 1, characterized in that prior to deposition   of the silicone layer ((37), an underlying layer (36) is deposited.   3. Method according to claim 2, characterized in that the underlying layer   consists of a layer of ink.   4. Method according to claim 3, characterized in that the deposited ink comprises a hardener.   5. Method according to one of claims 1 to 4, characterized in that the layer of   silicone (37) is polymerized after being deposited.   6. Method according to claim 5, characterized in that the silicone layer (37) undergoes a prepolymerization as soon as it is deposited on the substrate, prior to its actual polymerization.   7. Method according to one of claims 3 to 6, characterized in that the ink (36)   also undergoes a polymerization step, prior to the deposition of the silicone layer (37).   8. Method for continuously depositing a layer of silicone on a micromodule (32) integrating one or more integrated electronic circuits, characterized in that it consists first of all, in depositing by screen printing an underlying ink layer (36); * polymerizing this ink layer (36); * then depositing the silicone layer (37) on this ink layer (36), also by screen printing;   To and finally, to polymerize the layer of silicone (37) thus deposited.   9. Method according to claim 8, characterized in that the ink deposited comprises a hardener. 8 2812224   10. Method according to claim 8, characterized in that the silicone layer (37) and the ink layer (36) undergo a prepolymerization as soon as they are deposited on the   substrate, prior to their respective polymerization proper.   11. Method according to one of claims 8 to 10, characterized in that the   micromodules (32) are stored in two parallel rows on a continuous strip, and in that the respective deposition of ink and silicone takes place simultaneously according to a step-by-step process, according to a determined number of micromodules. 12. Installation for continuously depositing a layer of silicone on a micromodule (32) integrating one or more integrated electronic circuits, stored on a continuous strip support (30), characterized in that it comprises: * a reel (7) the reel for storing the strip (30) of micromodules; e a first screen printing table (10), associated with a screen printing screen (11), and a pair of doctor blades (12) and counter doctor blades (13), intended to deposit an ink layer according to a well-defined location of said micromodules; * an oven (15) for polymerizing the ink thus deposited; e a second screen printing table (29), associated with a screen printing screen (19) and a pair of doctor blades (20) and counter doctor blades (21), intended to deposit a layer of silicone (37) on said ink layer (36); * an oven (23) for polymerizing the silicone layer (37) thus deposited;   * a winding member (27) of the strip thus treated.   13. Installation for continuously depositing a layer of silicone on a micromodule (32) according to claim 12, characterized in that it further comprises members for centering and indexing the strip relative to the means of   deposition of ink and silicone respectively.   14. Installation for continuously depositing a layer of silicone on a micromodule   (32) according to one of claims 12 and 13, characterized in that the tables   (10) and (29) are heating, so as to induce a rise in temperature of the strip (30), capable of inducing a pre-polymerization of the ink and of the silicone respectively, prior to their passage through the oven ( 15) respectively (23).