GB2267682A

GB2267682A - Manufacturing an integrated circuit card

Info

Publication number: GB2267682A
Application number: GB9212221A
Authority: GB
Inventors: Charles Richard Jarvis
Original assignee: GEC Avery Ltd
Current assignee: Avery Weigh Tronix Ltd
Priority date: 1992-06-09
Filing date: 1992-06-09
Publication date: 1993-12-15
Anticipated expiration: 2012-06-09
Also published as: EP0645038A1; JPH07507970A; GB2267682B; WO1993025978A1; GB9212221D0

Abstract

An integrated circuit card is manufactured by forming an insert by mounting at least one electronic component on a flexible substrate provided with a conductive circuit thereon and providing electrical connections between the or each electronic component and the conductive circuit, and mounting the insert on a first polymeric dough layer (7) of a curable filled polymeric material, curing said first sheet, and either before or after the first sheet has been cured, bonding a second polymeric dough layer (8) of a curable filled polymeric material to the first layer with the insert therebetween, and curing said second layer. <IMAGE>

Description

AN INTEGRATED CIRCUIT CARD This invention relates to an integrated circuit card and to a method of manufacturing such a card.

An integrated circuit card is a card incorporating one or more electronic components, including an integrated circuit, capable of storing and, when activated by external means, processing data. Such cards may be used for storing personal data, and authorising and controlling monetary and other transactions, for example. The card of the invention may, for example, --be of the type disclosed and claimed in our UK Patent No. 2173623.

In a known technique for the manufacture of such cards, as disclosed and claimed for example in our UK Patent Application No. 2219960, the card comprises an insert consisting of a flexible substrate upon which are formed conductive tracks and to which the or each of the electronic components are adhered and provided with electrical connection to the tracks. The insert is adhered to a high tensile polyester skin in a mould, with a second skin spaced from the first at the opposite side of the mould space, and a reactive liquid polymer mix is injected into the space between the skins. The mould is then closed and, under the action of heat, the liquid polymer cures to a solid polymeric body. While the cards produced by such a process are satisfactorily durable, there can be a tendency for the surface of the card to follow the contours and outline of the insert within the card to a small degree. While this has no adverse effect on the operation of the card, its appearance can be slightly marred.

Additionally, there are difficulties in handling a liquid reactive polymeric material.

It is an object of the present invention to provide a method of manufacturing an integrated circuit card wherein the aforesaid disadvantages are minimised or overcome.

According to the present invention, a liquid reactive polymeric material is replaced by a curable polymer/filler mix having a consistency of dough and hereinafter referred to as a polymeric dough.

Accordingly, the present invention provides a method of manufacturing an integrated circuit card, the card comprising an insert including at least one electronic component, the method comprising the steps of mounting at least one electronic component on a flexible substrate having a conductive circuit, providing electrical connectors between the or each electronic component and the circuit, mounting the insert on a first layer of a polymeric dough curing the first layer, and locating a second layer of a polymeric dough on the first layer to sandwich the insert therebetween and curing the second layer.

Preferably, the first and second layers are cured substantially simultaneously.

A polymeric skin may be bonded to the outer face of each of said layers before said layer is cured.

In a method according to one embodiment of the invention, one of the polymeric dough layers is located on one polymeric skin, the insert is mounted on the upper face of the layer, which is then cured, and the second of the layers is located on the first layer with the insert between them. A second polymeric skin is bonded onto the second layer, which is then cured.

In a method according to an alternative embodiment of the invention, the insert is secured to a perforated flexible support and the support is then positioned with the insert between the two polymeric dough layers, each layer having a polymeric skin covering the outer surface thereof.

The resulting structure is pressed in a mould while the polymeric dough is cured.

The polymeric skins are preferably coated on their inner face, in advance of use with an acrylic blocked catalyst adhesive activatable by heat to bond to the polymeric dough layers.

Curing of the layers in the method of the invention may be by heating.

The or each polymeric dough may comprise a liquid polyester or other polymeric material, for example containing a blocked catalyst activated by heat. The filler in a quantity sufficient to provide the dough-like consistency may comprise particulate silica, for example, in the form of flakes and/or chopped strands, but preferably comprises a microfibre reinforcement, for example of fine fibres of calcium metasilicate, suitably about 90um long and with a 10:1 to 20:1 aspect ratio. The fibres may be surface-treated with a silane wetting agent, for example, a methacryloxysilane, to promote adhesion to the liquid polyester or other polymeric material.

Reference is made to the drawings, in which: Figure 1 is an exploded diagram illustrating a first method according to the invention; Figure 2 is an exploded diagram illustrating a second method according to the invention; and Figures 3A to 3C are diagrams illustrating apparatus for use in a third method in accordance with the invention.

Referring first to Figure 1, an insert 1 is formed in conventional manner from a thin flexible substrate 2 of a polymer such as a polyimide. The substrate 2 is very thin, for example, less than 25um and may be as thin as lOum. The substrate 2 has a conductive circuit, for example, of copper 25um thick printed thereon and with electronic components 3, 4 and 5, such as ICs, bonded to the substrate 2, for example by adhesives, and provided with wire connections to the circuit on the substrate. Fragile components may be encapsulated in a glob top resin.

A thin high tensile polyester skin 6 having a coating on its inner face of a heat activatable adhesive such as an acrylic blocked catalyst adhesive, is located in a suitable heated mould (not shown) and a polymeric dough layer 7 of a filled polyester moulding compound is located on the skin 6.

The dough layer 7 is formed of a liquid polyester mixed with a filler such as particulate silica, eg in the form of flakes and/or chopped strands preferably including a microfibre reinforcement such as fine fibres of calcium metasilicate e.g. of length 90um and with an aspect ratio in the range of 10:1 to 20:1. The filler may be treated with a wetting agent which may be a silane such as methacryloxysilane, prior to mixing, to promote adhesion of the liquid polyester.

The insert 1 is pressed onto the layer 7, and a second polymeric dough layer 8 is then placed on top of the resulting structure, with a second skin 9, e.g a thin polyester film less than 25um thick, also having an adhesive coating, on its confronting face. The resultant structure is rolled to expel any air trapped beneath the layer, and then pressed in the heated mould to cure the polymeric dough layers to form a solid polymeric body encapsulating the insert.

In an alternative method shown in Fig. 2, the insert 1 is attached to a thin flexible mesh 10 e.g. a sheet of "Melinex" (Trade Mark) in which suitable apertures are formed to receive the electronic components 3, 4 and 5.

The first skin 6 is located in the heated mould with the first polymeric dough layer 7 thereon, the mesh 10 with the insert 2 (or an array of inserts 2) attached to it is placed over the first layer 7, and the second polymeric dough layer 8, with its skin 9, is positioned on top of the mesh 10. A second half of the heated mould is pressed against the first half to effect curing of the layers 7 and 8. Preferably, the skins are rolled prior to closing of the mould to expel air trapped beneath them.

The embodiment above described whilst shown as manufacturing a single integrated circuit card, are readily adaptable to produce integrated circuit cards in batches of, for example, 20 cards produced from an array of 5 x 4 inserts on a continuous substrate 2 positioned with respect to commensurate upper and lower polymeric dough layers 7 and 8 and skins 6 and 9 in a mould of size to receive the array.

After curing, the array of cards so formed is chopped into individual cards.

As the layers 7 and 8 are each cohesive and can be handled mechanically, the invention is readily applicable to a continuous method of production in which the skins 6 and 9, the substrate 2, (and if provided, the support mesh 10) and the layers 7 and 8 are fed continuously to a successive plurality of heated moulds travelling at a matching speed and over a distance necessary to effect cure of the polymeric dough layers. The continuously formed web of cards so formed is then chopped to provide individual integrated circuit cards.

Referring now to Figures 3A, 3B and 3C, wherein the reference numerals refer to similar parts as above described, there is shown an apparatus for continuously manufacturing integrated circuit cards, in accordance with the present invention. The apparatus comprises a rotatable support 12 whereon a plurality of electronic modules, each incorporating an insert 2 and a plurality of components such as the components 3, 4 and 5, spooled on a support mesh 10 is mounted for feeding over a guide roller 14 to a mouth of the apparatus. Rollers 16, 17 support respective endless carrier films 18 and 19 which, in turn, support cohesive dough lauers 7 and 8 for feeding the dough layers to the mouth of the apparatus one at each side of the mesh 10.

The skins 6 and 9 are likewise fed to the mouth, from respective spool supports 20, 21, over quide rollers 22, shaping guide rollers 23 and between heated edge-pinch rollers 24 maintained at, for example, 1200C. The shaping guide rollers 23 (and additional guides, if necessary) form the skins to provide channel sections (see Figure 3B) which enclose the layers 7, 8 and the mesh 10 therebetween and the sandwich 27 so formed is fed to a forming duct 26. The forming duct 26 ensures registration and may assist in the exclusion of air from the sandwich.

The sandwich 27 so formed is fed to (or is drawn into) the nip between a pair of shaped endless belts (see Figure 3C) 28 extending around rollers 30, 32 which impart drive thereto. The-nip serves to expel any remaining air from the sandwich and to excert pressure thereon to ensure deformation of the dough layers 7, 8 to receive and encapsulate the electronic modules on the mesh 10. Shoes 34, heated to, for example, 1000C, provide therebetween, a curing path for the sandwich by the transfer of heat, through the belts 28, to the moulding compounds 7, 8, simultaneously causing adhesion of the skins to the layers 7 and 8 and the layers 7 and 8 to each other, to the mesh 10 therebetween, and to the components of the electronic modules supported on the inserts 2.

The path length provided by the belts 28, and the shoes 34 is arranged to effect sufficient curing of the compounds 7 and 8 that the strip of moulded cards exciting the lower (as shown in Figure 3A) nip can be passed to subsequent manufacturing stages such as printing, data recording and chopping into individual cards, without distortion from their planar laminate state.

Appropriate feed controllers and registration means are provided to ensure correct location of the inserts between the layers and of the skins 6 and 9, which preferably bear graphic representations on their surfaces.

Both methods- - produce a satisfactory card structure with a superior surface finish.

Claims

1. A method of manufacturing an integrated circuit card, the card comprising an insert including at least one electronic component, the method comprising the steps of mounting at least one electronic component on a flexible substrate having a conductive circuit, providing electrical connections between the or each electronic component and the conductive circuit, mounting the insert on a first layer of a polymeric dough, curing said first layer, locating a second layer of a polymeric dough on the first layer with the insert therebetween, and curing said second layer.

2. A method as claimed in claim 1 wherein the first and second layers are cured substantially simultaneously.

3. A method according to Claim 1 or 2, wherein a polymeric skin is applied to the outer face of each of said layers before said layer is cured.

4. A method according to claim 3, comprising locating one of said polymeric dough layers on one of the polymeric skins, mounting the insert on the upper face of the layer and curing the layer, locating the second of said polymeric dough layers on the first layer with the insert therebetween, locating a second polymeric skin on said second layer, and curing the second layer.

5. A method according to Claim 3 or 4, comprising securing the insert to a perforated flexible support, positioning the support and the insert between said two polymeric dough layers and with a respective polymeric skin covering the outer surface of each layer, and pressing the resultant structure in a mould while curing the polymeric dough layers.

6. Amethodaccording to claim 3, 4 or 5, comprising the step of rolling to expel air from within the multilayer structure.

7. A method according to any of claims 3 to 6 wherein each polymeric skin is coated with an acrylic blocked catalyst adhesive on the surface thereof which confronts the respective polymeric dough layer.

8. A method according to any preceding Claim, wherein the layers are cured by heating.

9. A method according to any preceding Claim, wherein the layers comprise a filled liquid polyester mix to provide the dough like consistency.

10. A method according to Claim 6, wherein the filler comprise particulate silica or a fibrous material such as calcium metasilicate.

11. A method of manufacturing an integrated circuit card, substantially as described with reference to and as illustrated in Fig. 1 or Fig. 2 of the drawings.

12. An integrated circuit card comprising an insert formed by a flexible substrate having an electrical circuit thereon, at least one electronic circuit component mounted on the substrate and connected to the circuit, the insert being sandwiched between layers of a cured polymeric material having skins applied to the outer surfaces thereof.

13. An apparatus for carrying out the method as claimed in claim 1, comprising feed means for feeding an insert in the form of a flexible substrate having at least one electronic component mounted thereon and electrically connected thereto between first and second layers of polymeric doughs, means for pressing the sandwich so formed to embed the insert in the layers, and means for curing the polymeric dough layers sufficiently to ensure the integrity of the laminer structures of the sandwich.

14. An apparatus for manufacturing an integrated circuit card substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.