WO2008107274A1

WO2008107274A1 - Process for manufacturing a device comprising an integrated circuit and an antenna coil connected to it

Info

Publication number: WO2008107274A1
Application number: PCT/EP2008/051736
Authority: WO
Inventors: Thierry Roz; Abdul-Hamid Kayal
Original assignee: Em Microelectronic-Marin Sa
Priority date: 2007-02-21
Filing date: 2008-02-13
Publication date: 2008-09-12
Also published as: WO2008107230A1

Abstract

A device comprising an integrated circuit and an antenna coil, with or without a support for winding the coil, is produced in the following manner: firstly, an electronic module comprising the electronic circuit and two electrical connection leads or tabs is formed; then, said coil is formed by firstly surrounding a first lead; next, the winding of the coil is carried out; and, finally, the second lead is surrounded. The joining of the ends of the coil to the two leads of the electronic module is carried out in the configuration resulting from the winding.

Description

Case 2687 GS / ert

Method of manufacturing a device comprising an integrated circuit and an antenna-coil connected thereto

The present invention relates to a method of manufacturing a device comprising an integrated circuit and an antenna-coil connected thereto. The integrated circuit and the antenna coil to which it is connected define a transponder with or without a common support. In particular, the invention relates to the manufacture of a device comprising a transponder mounted on a plastic support.

To optimize the production of transponders, it is important to be able to automate such a production as much as possible.

As a rule it is intended to carry out a winding and then to weld the two ends of this coil, defining an antenna coil, on two pads of a PCB on which the integrated circuit is arranged. This integrated circuit is connected to conductive tracks of the PCB, two of which terminate in electrical contact pads to which the two ends of the coil are respectively electrically connected. To protect the circuit and the connection to the coil, it is known to then deposit a drop of resin on the electronic circuit. Such a conventional technique is well known to those skilled in the art. It will be noted that the contribution of the two ends of a coil to the two corresponding ranges of a PCB or any substrate is a difficult operation to automate. Often such an operation is performed by workers. In the case where the coil is mounted on a support, the input of the integrated circuit mounted on its substrate, the connection of the ends of the coil on two ranges of the substrate and finally the protection of at least the electronic circuit by a resin supply can be difficult to automate.

To solve the problem of electrical connection of a coil to an integrated circuit, it has been proposed in particular in EP 0 573 469 an installation for forming the winding of a coil while passing the electric wire to- above two electrical contact pads arranged on the integrated circuit itself. The electrical wire is thus guided so that the two ends of the coil, in the installation where the coil winding is formed, pass respectively above the two respective ranges of the integrated circuit. Once the winding has been completed, the two ends of the coil are soldered to the two contact pads of the circuit, in particular by thermo-compression. In particular, it is learned from EP 0 588 944 that such a procedure requires arranging bumps on the surface of the electronic circuit. To correctly perform the welding by thermo-compression, it is necessary that these bumps have a certain height and also a relatively large surface. Preferably, these bumps are made of gold, which makes the product more expensive. Note that in the case where the bumps are arranged above the integrated elements, special precautions must be taken according to this document. It is difficult to obtain a high industrial efficiency with such a transponder manufacturing because of the stresses to which the integrated circuit is subjected during the thermocompression of the two ends of the coil on its two bumps. To reduce this problem, one can arrange the bumps in a region outside the integration area, but then the surface of the integrated circuits is increased relatively significantly, which also increases the cost of manufacturing such integrated circuits.

The method of manufacturing transponders by thermo-compression mentioned above has another major disadvantage in the case where it is intended to perform the winding on a plastic support. One could imagine brought the integrated circuit also on the plastic support and the maintain in a given area by a suitable tool or by fixing it to the support in particular by gluing before carrying out the thermo-compression. However, since the thermo-compression requires a relatively high heat input, it is difficult, if not impossible, not to generate deformations of the plastic support during such an operation. Depending on the shape of the plastic support and the arrangement of the coil thereon, one could certainly imagine keeping the integrated circuit in a tool a little removed from this support to perform the thermo-compression. However, the disadvantages mentioned above remain. The object of the present invention is to meet the drawbacks mentioned above by providing a method of manufacturing a device, comprising an integrated circuit and a coil together forming a transponder, which firstly makes it possible to easily connect the ends of the coil to the means of electrical connection of the integrated circuit, secondly to use a support for the plastic material coil to which the integrated circuit can be attached, and thirdly to ensure good protection of the integrated circuit throughout the manufacturing process of a device according to the invention and subsequently.

To this end, the present invention relates to a method of manufacturing a device comprising an integrated circuit and a coil defining a communication antenna, the integrated circuit and the coil together forming a transponder, this method comprising the following steps:

A) forming an electronic module comprising said integrated circuit and at least two electrically conductive tabs intended to be connected to both ends of said coil;

B) forming said coil by firstly bringing an electrical wire around a first of the two tabs, then by carrying out a coil winding and finally by bringing the electrical wire around the second of the two tabs or against this second tab, both legs being assembled at the respective two ends of said coil in the resulting winding configuration. - AT -

According to a particular variant of this first mode of implementation of the method, the electric wire is wrapped around the first leg before making said coil winding so that the electric wire is retained by the first leg to allow it to be stretched from this first tab and to perform (coil winding.) The first tab thus defines a docking pin or a point of attachment of the electric wire, a great advantage of this preferred embodiment of the method according to the invention. It arises from the fact that it is not necessary to provide auxiliary means in the installation to tension the electrical wire on the side of the first end of the coil to wind with a tight wire. first leg of the electronic module which serves as a docking pin or point of attachment of the electric wire.It is thus possible to easily perform the coil winding provided after mooring o u attached the wire to the first leg of the electronics module. In addition, the first leg is thus directly assembled at the first end of the coil. By "winding" it is understood that the electric wire performs more than one turn around the leg. On the other hand, the expression "bring around" also encompasses the case where the electric wire bears against the leg and has at this point an angular deflection of less than 360 degrees, but at least of the order of magnitude of the ten degrees. .

According to a preferred variant, the electric wire is also wound around the second leg after having made the coil winding. Thus the second tab also defines a docking pin or an attachment point for the electrical wire, which then allows to cut the wire downstream of the second leg without the risk that the two ends of the coil thus formed separate electrical connection tabs. In addition, the second end of the coil is thus directly assembled to the second leg.

Thanks to the characteristics of the method according to the invention, the two ends of the coil are brought into direct contact with the two respective tabs of the electronic module during the formation of the coil, which makes it possible to fix them then easily and to ensure the electrical connection between these two ends of coil and the two legs of the electronic circuit.

By using a gripping tool of the appropriate electronic module, it is possible to make the electrical connection between the electronic module and the two coil ends by a supply of heat or solder without deforming, if necessary, a plastic support of the coil winding.

The electronic module is preferably formed of an integrated circuit mounted on a metal substrate defining at least two tabs or conductive tabs and coated with a resin. Such modules can be easily produced in large numbers and at low prices.

Note that the only operation of winding the electrical wire around a tab of the electronic module could be sufficient for assembly. In particular, it is possible to provide tabs with an enlargement at their free end. However, to ensure a rigid connection and a good long term electrical connection, it is preferable to weld or glue the electrical wire wound around the tab to it. To do this, the skilled person has many means and materials, including electrically conductive glues. It will be noted, however, that the electrical wire is generally surrounded by an insulating sheath, which may be melted or sublimated for a particular heat input.

The invention also relates to a method of manufacturing a device comprising an integrated circuit and a coil defining a communication antenna, this coil and this integrated circuit forming a transponder, this method comprising the following steps: A) Formation of a module electronics comprising said integrated circuit and at least two electrically conductive tabs for connection to both ends of said coil;

B) forming said coil by firstly providing an electrical wire against a first of the two tabs, then by winding a coil and finally bringing the electric wire against the second of the two tabs, at least the first tab defining in this step a guide pin for said electrical wire which is stretched against this first tab, the two tabs being electrically connected to both ends of said coil in the resulting configuration of the coil. Preferably, the two tabs are fixed at both ends of the coil while the electric wire is still stretched in the winding installation.

In this second embodiment of the invention, the two tabs define guiding pins for the electric wire during the formation of the coil winding. Thanks to this characteristic, the electric wire is directly in contact with the two legs of the electronic module, so that it is easy to fix the two ends of the coil to these two tabs in the installation provided for the winding. Fixing the electric wire to both legs can be done by any means known to those skilled in the art.

In a particular variant, the electrical wire is fixed to the first leg, in particular by welding or gluing, before carrying out said coil winding, this electric wire being fixed to the second leg following the formation of this winding. The first leg thus defines a pin for fixing the electric wire. It is then possible to extend it from this first tab and to carry out said coil winding. Such a variant is also envisaged for the first mode of implementation of the method.

Other features and advantages of the manufacturing method according to the invention will also emerge from the description of the invention given hereinafter with reference to the drawings, given as non-limiting examples, in which:

- Figure 1 shows a plurality of integrated circuits encapsulated and supported by a perforated metal film;

- Figures 2A and 2B schematically show two variants of electronic modules cut in the structure of Figure 1; - Figure 3 schematically shows an installation in which a coil is formed on a plastic support with both ends electrically connected to two legs of an electronic module of the type shown in Figures 2A and 2B; FIGS. 4A and 4B schematically represent two variants of the method of manufacturing a device comprising a coil electrically connected to an electronic module according to the invention;

FIG. 5 represents a device obtained by the manufacturing method according to the invention; FIG. 6 schematically shows a variant of a device obtained by the manufacturing method according to the invention;

- Figure 7 shows schematically an installation, similar to that of Figure 3, for producing transponders without coil support; and FIG. 8 schematically shows a partial view from above of an installation in which a second mode of the method according to the invention is implemented.

A first embodiment of the manufacturing method according to the invention will be described hereinafter with reference to FIGS. 1 to 6. The devices manufactured in the context of the method of the invention comprise an integrated circuit and a coil. This coil and this integrated circuit are electrically connected in the context of the manufacturing method according to the invention.

First, it is intended to form electronic modules 2 which comprise an integrated circuit 6 and at least two electrically conductive tabs 8, 10 electrically connected to the integrated circuit and defining contact pads for both ends of a coil. Preferably, the two tabs are formed by a perforated or cut metal film 4 and on which the integrated circuit is mounted. This assembly can be achieved by any technique known to those skilled in the art. Then, preferably, it is intended to coat the integrated circuit in a resin or a mass 12. The protection of the integrated circuit and its electrical connections to the two metal tabs can be achieved in various ways known to those skilled in the art. For example, it is possible to deposit on the integrated circuit a drop of resin, taking care that it does not cover the two connection lugs. Preferably, the perforated metal film 4 is introduced into a material injection installation for coating or encapsulating the integrated circuits 6 so as to protect them and their electrical connections to the metal tabs. In this way, coated or overmolded circuits 12 are obtained with the two connecting lugs 8 and 10 coming out of this coating or overmolding.

Then, each electronic module 2 is cut from the frame defined by the film 4 according to two variants shown in Figures 2A and 2B. In the first case, the electronic module 2A essentially comprises the overmolded or coated integrated circuit 12 and the two connection tabs 8 and 10 emerging from the overmolding or the coating. In the second case, the electronic module 2B further comprises a third lug 14 initially defined by the perforated metal film 4 and used to stiffen the parts of the film where the integrated circuits are respectively mounted. This tab 14 has no electrical function but can be used for positioning and / or maintaining the electronic module 2B on a support, as will be described later. The tabs 8 and 10 are preferably rectilinear and have a certain mechanical resistance to deformation. In other words, they have a certain rigidity.

It will be noted that other embodiments of the electronic module 2A, 2B may be provided by those skilled in the art. In particular, the film 4 used for forming the electronic modules may consist of a plastic film having at least one of its two metallized faces. Thus, the connecting tabs 8 and 10 may in a first variant be formed by all-metal tongues, whereas in a second variant, these tabs 8 and 10 are formed by tabs plastic material metallized at least on one of the two faces of each tongue.

With the help of Figure 3, we describe the second step of the method of manufacturing a device according to the first embodiment of the invention. In this step, it is intended to form the coil and connect its two ends to the two legs of an electronic module 2A or 2B (the module 2A being shown by way of example in Figure 3).

The installation 20 comprises means 22 for supplying an electric wire 24 for making a coil 26 on a portion of a plastic support 28. The means 22 define a three-axis system, the portion 30 being movable along the Y axis , the portion 32 being movable along the X axis and the portion 33 being movable along an axis perpendicular to the XY plane.

The electrical wire 24 is brought or brought first around the first leg 8 of the electronic module 2A, as shown schematically in Figures 4A and 4B. Then, a winding 30 is made around a portion of a support 28 of substantially cylindrical shape. This support 28 is mounted on an arm 38 which can rotate on itself so as to rotate the support 28 around its central axis. Then, the electric wire 24 is pulled again towards the module 2A and brought around the second leg 10 of this electronic module.

During the formation of the coil 26, the electronic module 2A is held in a given position by a suitable gripping means 40. This means 40 is shown very schematically in the figures.

When forming the coil shown in FIG. 3, each of the two lugs 8 and 10 defines an angle α between its longitudinal direction and the corresponding end 42, 44 of the coil which passes around this lug, measuring from the end free of the paw. Preferably, this angle α is approximately equal to 90 ° or greater as shown in FIG. According to an advantageous characteristic, the electric wire is wound around the first leg 8 before effecting the coil winding 36. Thus, this first tab defines a docking pin or an attachment point for the electric wire; which then makes it possible to tension it from this first tab and to carry out said coil winding. In this case, it is not necessary to have auxiliary means in the installation to hold the wire at a first end so as to be able to tension it correctly to carry out the winding. The first connector of the electronic module itself forms an attachment point or a pico for the electric wire during the formation of the coil. According to a particular characteristic of the invention, the electric wire is also wound around the second leg 10 after the coil winding 36 has been made. The second leg thus also defines a docking pin or an attachment point for the electrical wire. This then makes it possible to sever the wire quickly, before securing the ends of the coil to the two terminal pads of the module 2A, in particular by welding or gluing.

According to a preferred variant, the two ends 42 and 44 of the coil are fixed by welding or possibly by gluing to the two lugs 8 and 10 after the formation of the coil 26. This fixing is performed directly in the resulting configuration of the winding in the installation 20. For example, welding is performed using a heated tip applied on each end wrapped around a respective tab. It is also possible to carry out the welding by a solder or by any other appropriate means known to those skilled in the art. A welding device 44 has been shown schematically in FIG. 3. It is mounted on a movable arm making it possible to approach the tip of this device 44 of each of the two tabs 8 and 10 while keeping the position of the electronic module 2A identical to that intended for the formation of the coil.

According to a first variant, the electrical wire 24 is welded or glued to the first tab 8 directly after this wire 24 has been brought around this first tab. This ensures a rigid attachment point for then perform the coil winding. In a second variant, the two ends 42 and 44 of the coil are welded or possibly glued to the two respective tabs after the formation of this coil.

Figures 4A and 4B show two alternative arrangements of the ends 42 and 44 of the coil 26 relative to the module 2A. In the first case, the two ends 42 and 44 of coil 26 intersect in projection in the plane of Figure 4A. In the second case, the winding 36 is made in such a way that the two ends 42 and 44 move away from each other from the two lugs 8 and 10. Once the coil 26 has been formed and the fastening of its two ends to the electronic module 2A made, it is provided, in a first variant shown in Figure 5, to deposit the module 2A on a drop of glue 50 placed at the bottom of a flat housing of the plastic support 28. It will be observed that the 2A module is glued in a supine position, that is to say it undergoes a rotation of about 90 degrees between the winding position and the fixing position to the support 28. Note that it is possible to fix the initial part of each of the two ends of the coil by depositing a drop of glue at the corresponding location on the winding 36. This produces a device 48 according to the invention. Fixing the ends of the coil to the lugs of the electronic module was performed by welding with a supply of solder.

It will be noted that the support 28 is given by way of non-limiting example. This support can in another variant form a magnetic core for the coil. The module 2A may for example be glued to one of the two ends of the magnetic core. However, in a variant, it is possible to leave free the electronic module connected to the coil, that is to say that the electronic module is mechanically connected to the coil only by the two ends thereof. Note also that in Figure 3, the electronic module 2A is held above the support 28 during winding, that is to say during the formation of the coil. However, it is also possible to first put this electronic module 2A on the support 28. It is even conceivable to provide to fix firstly the electronic module to the support before winding. In the latter case, it is possible under certain specific conditions to remove the gripping means 40 during winding. Regarding the welding, it is also possible to perform it only after bringing the electronic module to the support 28 and to perform this welding for example in a specific position of the planned installation. In the latter case, the skilled person will have to ensure that each end of the coil remains properly wound around the corresponding connecting tab. Several variants of implementation of the method according to the invention can therefore be provided by the skilled person without departing from the scope of the present invention as claimed.

In Figure 6 is shown a variant of the device obtained by the manufacturing method of the invention. The device 54 comprises a support 28 and a coil 26 which is amilar with the device 48 of FIG. 5. On the other hand, in the case of FIG. 6, an electronic module 2B, represented in FIG. 2B, has been used to produce the device 54. The third metal tab 14 has been folded and inserted into a slot 56 arranged at the bottom of the housing provided for the electronic module 2B. By sizing the slot 56 so that the tab 14 is pinched after its introduction into this slot, it is then possible to avoid having to bring a drop of glue on the support 28 before assembling the module 2B to this support. For example, the walls of the slot 56 have a certain elasticity, in particular in the case of a plastic support. It is also conceivable that the slot 56 is first filled with a soft adhesive mass, a gelatin or any other material having a certain adhesion to the tab 14 to ensure its retention in place of the tab 14 after it 14 has been introduced into the slot 56. It will be noted here that the fixing and the holding in position of the module 2B by the lug 14 may be temporary and that a fixing, particularly by gluing, is carried out in another station of the manufacturing facility. 54. The fixing of the ends of the coil to the lugs of the electronic module was performed by a heated blade or a jet of ignited gas. In Figure 7 is shown schematically an installation 60 for producing transponders with a coil 26 having a winding 36 self-supporting, that is to say without internal support. The references already described above will not be described again here in detail. The installation 60 is distinguished from the installation 20 essentially by the fact that the winding 36 is carried out on a support 62 of the installation. In particular, the support 62 is provided retractable. In a first variant, the electronic module 2A is left free, that is to say mechanically connected to the winding 36 only by the two ends of the coil. In a second variant, the module 2A is fixed to the winding, in particular by gluing on the outer edge of this winding.

With the help of Figure 8 which shows a partial view of an installation similar to that of Figure 7, will be described hereinafter a second embodiment of the method according to the invention. This second embodiment differs from the first mode of implementation in that the electric wire forming the coil 26 is not wound around the two lugs 8 and 10 of the electronic module during winding. Here, during the formation of the coil, firstly brings an electric wire 24 against a first leg 8 by partially rotating around this tab. Then, the winding 36 is carried out and finally the electric wire is brought against the second lug 10. Here the two connecting lugs 8 and 10 define guide pins for the electric wire. It is therefore necessary to have auxiliary means in the installation for sufficiently stretching the electrical wire on the side of the first end 42. As shown in Figure 8, the electric wire preferably passes inside the two legs 8 and 10. Once the coil is made, the two tabs are electrically connected to both ends 42 and 44 of the coil directly in the resulting winding configuration. Preferably, the electric wire is arranged against the two lugs 8 and 10 so as to substantially go along their face opposite to the winding 36. This makes it easier to fix the ends of the coil to these connection tabs of the module. electronic. Fixing is performed in particular by soldering with solder, for example tin or gold. In a first variant, the fixing of the two tabs to the two respective ends of the coil is performed after the formation thereof. In a second variant, the electric wire is fixed firstly to the first leg 8 before winding the coil, while it is fixed to the second leg 10 only following the formation of this winding. In the latter case, the first tab 8 defines a pin for fixing the electrical wire for the formation of the coil winding and the transponder assembly.

Claims

REVEN DICATIONS

A method of manufacturing a device comprising an integrated circuit and a coil defining a communication antenna, said method comprising the following steps: A) forming an electronic module comprising said integrated circuit and at least two electrically conductive tabs for be connected to both ends of said coil;

B) forming said coil by firstly bringing an electrical wire around a first of the two tabs, then by carrying out a coil winding and finally by bringing the electrical wire around the second of the two tabs or against this second tab, both legs being assembled at the respective two ends of said coil in the resulting winding configuration.

2. Method according to claim 1, characterized in that said electric wire is wrapped around said first tab before carrying out said coil winding, said first tab defining a docking pin or a point of attachment of said electric wire to allow it to be stretched from this first tab and to perform said coil winding, said first tab thus being directly assembled to the first end of the coil.

3. Method according to claim 2, characterized in that said electric wire is also wound around said second leg after having carried out said coil winding, said second leg also defining a mooring pin or a point of attachment of said electric wire. and thus being directly assembled at the second end of the coil.

4. Method according to one of the preceding claims, characterized in that said electrical wire is fixed by welding or gluing to both legs after forming the winding so as to provide a rigid connection and an electrical connection between the electric wire and each of the two legs.

5. Method according to one of claims 1 to 3, characterized in that said electric wire is fixed by welding or gluing to said first leg before effecting said winding.

6. Method according to one of the preceding claims, characterized in that said electronic module is oriented during the formation of the coil so that the two ends of this coil define with the respective longitudinal directions of said two legs an angle, measured since the free end of each leg, approximately equal to 90 degrees or greater.

7. Method according to one of the preceding claims, characterized in that said winding is performed on a plastic support to which said electronic module is attached after said electric wire has been fixed to the two tabs and electrically connected thereto.

8. A method of manufacturing a device comprising a transponder formed by an integrated circuit and a coil defining a communication antenna, this method comprising the following steps:

B) forming said coil by firstly providing an electric wire against a first of the two tabs, then by winding a coil and finally bringing the electric wire against the second of the two tabs, at least said first tab defining in this step a guiding pin for said electrical wire which is stretched against this first tab, the two tabs being electrically connected to the two respective ends of said coil in the resulting configuration of the coil.

9. The method of claim 8, characterized in that the two tabs are fixed at both ends of said coil while said electrical wire is still stretched in the winding installation.

10. The method of claim 8, characterized in that said electrical wire is attached to said first leg before performing said coil winding while it is attached to said second leg following the formation of this winding, said first leg defining in this step a pin for fixing said electrical wire to allow it to be stretched from this first tab to effect said coil winding.