CA2206786C - Electronic module of extra-thin construction - Google Patents

Electronic module of extra-thin construction Download PDF

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Publication number
CA2206786C
CA2206786C CA002206786A CA2206786A CA2206786C CA 2206786 C CA2206786 C CA 2206786C CA 002206786 A CA002206786 A CA 002206786A CA 2206786 A CA2206786 A CA 2206786A CA 2206786 C CA2206786 C CA 2206786C
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CA
Canada
Prior art keywords
electronic module
system support
lugs
chip
casing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CA002206786A
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French (fr)
Other versions
CA2206786A1 (en
Inventor
Karl Nicklaus
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Besi Switzerland AG
Original Assignee
Esec Sempac SA
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Filing date
Publication date
Priority claimed from CH363392A external-priority patent/CH686325A5/en
Application filed by Esec Sempac SA filed Critical Esec Sempac SA
Publication of CA2206786A1 publication Critical patent/CA2206786A1/en
Application granted granted Critical
Publication of CA2206786C publication Critical patent/CA2206786C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/26Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/31Structure, shape, material or disposition of the layer connectors after the connecting process
    • H01L2224/32Structure, shape, material or disposition of the layer connectors after the connecting process of an individual layer connector
    • H01L2224/321Disposition
    • H01L2224/32151Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/32221Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/32245Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42Wire connectors; Manufacturing methods related thereto
    • H01L2224/47Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/4805Shape
    • H01L2224/4809Loop shape
    • H01L2224/48091Arched
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42Wire connectors; Manufacturing methods related thereto
    • H01L2224/47Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481Disposition
    • H01L2224/48151Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/48221Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/48245Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H01L2224/48247Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic connecting the wire to a bond pad of the item
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42Wire connectors; Manufacturing methods related thereto
    • H01L2224/47Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/49Structure, shape, material or disposition of the wire connectors after the connecting process of a plurality of wire connectors
    • H01L2224/491Disposition
    • H01L2224/4912Layout
    • H01L2224/49171Fan-out arrangements
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/73Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
    • H01L2224/732Location after the connecting process
    • H01L2224/73251Location after the connecting process on different surfaces
    • H01L2224/73265Layer and wire connectors
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/15Details of package parts other than the semiconductor or other solid state devices to be connected
    • H01L2924/181Encapsulation

Landscapes

  • Casings For Electric Apparatus (AREA)
  • Credit Cards Or The Like (AREA)

Abstract

The invention relates to an electronic module having a semiconductor chip mounted on a system support member in a plastic housing. The system support member having outer contacts and lugs projecting beyond the housing, which lugs have engaging and/or positioning contours for cooperating with automated assembly machines.

Description

ELECTRONIC I~~IODULE OF E~iTRA-TI-IIN CONSTRUCTION
k r nd of the Inventi~
The present invention relates to an electronic module and to a chip card containing such an electronic module.
s Prior Art An electronic module of this type is disclosed in US Patent 5,134,773. That patent disclosed a process facilitating the production of so-called chip cards by directly embedding the module into the plastic material forming the card, with the outer contacts exposed on one side of the card. The resulting electronic module is ro advantageous especially insofar as its outer contacts and the chip pad are composed of a system support member in the form of a sheet-metal structure (lead frame);
this enables efficient, low-cost manufacture of the modules by well-known processes and with the aid of automated assembly machines which are commonly used in the assembly of semiconductor components for integrated circuits.

Yet electronic modules of extremely flat design imply peculiar problems for their manufacture. In distinction to the widely used design in which both the system support member and the semiconductor chip are on both sides covered with moulded plastic, i.e., embedded lIl a housing of adequate thickness (e.g., a so-called DIP
s housing for mounting on printed circuit boards), only a very limited structural height is available for accommodating the overall thickness of the electronic module.
For example, chip cards have a thickness of only 0.8 mm, and similar limitations to the thickness of the module exist in other applications of flat-housing modules, e.g., in so-called electronic keys or the like. Not only must the module be very firmly fixed in ro such objects like chip cards so that the chip cards are sufficiently rugged to remain properly f~rnctioning even under the considerable mechanical and thermal loads occurring in their utilisation, but also its parts electrically interacting with external elements, i.e., its outer contacts, IIlUSt be arranged exactly at predetermined points on the chip card and, hence, in the module's housing proper. This implies that in each operation, the modules can be arranged precisely in a simple fashion during their manufacture and further handling, e.g., their mounting in chip cards. It is therefore a problem underlying the invention to provide an electronic module the configuration of s which allows precise positioning of the outer contacts during manufacture and mounting, and this is to be accomplished by means available in the utilisation of conventional automated assembly machines.
Summary of the Invention It is an object of the present invention to ameliorate the stated disadvantages.
According to one aspect of the invention, there is provided an electronic module of flat design, having outer contacts which are joined with a plastic housing and formed by a system support member in the form of a flat sheet-metal structure, and having a semiconductor chip mounted on the system support member and embedded in the plastic housing, the system support member being provided with lugs projecting beyond the plastic housing and having engaging and/or positioning contours which have a well defined position vis-a-vis the outer contacts of the electronic module and which are designated for cooperating with automated assembly machines.
'rlie lugs, which are formed by portions of the system support member, have contours, in general cutouts, which, like the outer contact proper, are produced by stamping, possibly simultaneous stamping, and therefore can be made in the right form relative to the outer contacts and, hence, have a precise position relative to the outer contacts. These lugs serve for both positioning the system support member with a chip mounted thereon when an intermediate product, namely the module, is made, and positioning the module in its further handling to render an end product, such as a chip card.
Typical embodiments of the subject of the present invention are described ~ o below in greater detail, by reference to and in conjunction with the drawings, as follows:
Brief description of drawings Fig. 1 shocas a system support of the module in accordance with a first typical embodiment;
Fig. 2 and 3 are part details of consecutive stages of manufac-ture of the electronic module, based on the system support shown in figure 1;
Fig. 4 is a diagrammatic section along line IV-IV in figure 2, and shows an injection mould in which an intermediate product in accordance with figure 2 has been inserted for the manufacture of the plastic casing;
Fig. 5 .is a section along line V-V in figure 3, and shows a finished module cut free from the system support and further deformed;
Fig. 6 is a perspective view of the electronic module in au~~tudnce with zhe zirst embodiment;
Fig. 7 is a section at a somewhat larger scale and shows a module placed in a further injection mould in which the module is embedded for the manufacture of a chip card;
Fig. 8 is similar to figure 1 but shows another type of system support, in accordance with a second embodiment;
Fig. 9 and 10 are similar to figures 2 and 3, and show the corresponding subsequent stages of manufacture of the second embodiment;
Fig. 11 is a plan view of the finished module according to the second embodiment;
Fig. 12 is a larger-scale section along line C-C in figure 11;
and Fig. 13 is a corresponding section along line D-D in figure 11.
Detailed description of invention The following first describes details of the system support 20 by reference to figure 1, then follows a description of the manufacture and construction of the complete electronic module according to the first embodiment.
Figure 1 is drawn at a very large scale and shows a section of a system support 20, also known as a lead frame, usually die-cut or punched out of thin, flat metal strip. Dot-dashed lines along both sides indicate further similar adjacent ~~CLL1UIIS oz zhe strip; in other words, a thin, flat sheet metal strip is die-cut or punched out in a known manner and consists of several sections identical to that shown in figure 1. Cent-rally of the system support 20 is a rectangular, preferably square, chip pad 22, limited by straight lines. Its boundaries are formed by slits 23, and the chip pad is held by bridges 25 on both sides. Several further slits 24 branch out from the slits 23, which together with other die-cut or punched cutouts . form more or less rectangular areas 21 that serve as the exter-nal contacts of the finished electronic module. The present embodiment shows a module typical of those used in chip cards, which in accordance caith current standards has a total of eight external contacts 21, i.e. two sets of four arranged in parallel rows. To show this more clearly, a dot-dashed line in figure 1 outlines the contact area 21a on one such external contact.
In the present example there are perforations 31 in the contacts 21 and in the bridges 25 in the areas adjacent to the chip pad 22. Further out, window-like perforations 29 are pro-vided in each of the external contacts 21 and in the two bridges 25. More or less in line with these perforations, the contacts 21 and the bridges 25 are connected to one another by webs 28 at the ends of the slits 24. The bridges 25 and the contacts 21 extend further to form lugs 26, 27 that project beyond the webs 28. Finally, pairs of dashed parallel lines 30 roughly describe a rectangle in figure 1, in the region of the webs 28 and the av-~:niiCU WlIIdUWS ::9, and indicate the lines along which the extension lugs 26 and 27 are later bent over. The importance of the details of~ the system support 20 referred to in this para-graph is described in greater detail below in connnection with the manufacture of the module and its integration in a moulded object.
The chip pad 22 .is made to receive a semiconductor chip whose integrated circuitry is electrically connected to the external contacts 21 in a well-kno~nn manner. In figure 1, a thick dot-dashed line shows two possible sizes and positions of such chips: la indicates a square chip that fits completely within the area of the_chip pad 22; but much larger chips can also be mounted, which may project well beyond the pad 22 and overlap adjacent parts of the external contacts 21; lb indicates the outline of such a larger, rectangular chip, of a size and shape that may be regarded as about the maximum possible for the example shown.
Of special importance is the fact that the slits 23 which form the boundaries of the chip pad 22 lie at an angle to the edges of the square or rectangular chip 1, preferably, as shoran, the oblique angle is about 45°. It is of further advan-tage if at least some of the slits 24 that extend from the slits 23 are "doglegged", i.e. extend along bent lines as shown, so that they are also oriented at least partly at an angle to the edges of the chip, particularly within the outline of the chip format lb. In the thin metal structure of the system support 20, the aforesaid slits 23, 24 inevitably form lines of weakness.
On the other hand, any fracture due to bending stresses in the monocrystalline material (usually silicon) of which chips are made, almost always occurs parallel to the edges of the chip.
The shaping of the lead frame and alignment of the chip on the chip pad, respectively, as described above, ensure that the lines of weakness in the supporting metal structure are not - parallel with the probable fracture lines in the chip; this greatly reduces the risk of fracture of the chip which is me-chanically bonded into the module.
In the present example the layout and arrangement are such that the diagonals of the square chip pad 22 are parallel and at right angles to the two rows of external contacts 21;
without any change in the alignment of the diagonals, the chip pad could also be rhomboid in shape. However, for example where the external contacts are arranged differently, a so-called in-"inverse" layout would also be feasible, i.e. one in which a square or rectangular chip pad is parallel to the main axes of the system support 20 and the chip is mounted at an angle the-reto. The lines formed by the slits 24 that separate the con-tacts 21 can also be varied, so that the desired effect achieved is greater or less, depending on the lengths of slit extending obliquely to the chip, especially in' the areas where the chip itself overlaps.
iim :gain stages in the manufacture of the electronic module are described below, by reference to figures 2, 3, and 4, and based on the system support 20 shown in figure 1. Figure 2 shows a rectangular semiconductor chip 1 mounted on the system support's pad 22. Thcagh this chip 1 is somewhat smaller than the maximum possible size lb indicated in figure 1, it projects considerably beyond the chip pad 22 and overlaps adjacent parts of the external contacts 21. Plire connections 3 from the chip's . semiconductor circuit to the external contacts 21 are made in a known manner. Insulating adhesive film 2 is,preferably used to attach the chip to the metal-plate structure of the system sup-port 20 to ensure its mechanical bond thereto. In the present case the film 2 is about the same size and shape as the chip and is made of heat-resistant synthetic resin, such as polyimide or polyester, with an adhesive coating that polymerizes when hea-ted. Such a film 2 used for fitting of the chip 1 has the ad-vantage that it can compensate a large range of thermal expan-sion as between the metal system support and the chip material, and also protects the chip by its ability to absorb shocks that act upon the system support. In addition, the film 2 insulates the chip electrically from the external contacts 21. Assembly and the wire connections 3 from the chip 1 to the external con-tacts are effected by proven, fully automated high-performance assembly equipment, such as that widely used for the assembly of semiconductors on system supports (such as lead frames or other substrates).
After assembly as shown in figure 2, the assembled system support 20 is placed in an injection mould for the manu-facture of a thin, flat plastic casing, as figure ~ diagramma-tically shows; this should preferably be a multiple mould that can accommodate several modules at a time. The entire tree sur-face of the flat system support 20 lies in close contact with the practically flat surface of the mould's bottom half 40, and the top half girl of the mould forms a void 10'. Plastic material is then injected into this void 10' and pressed around the chip 1 and between parts of the system support 20, to form the outer shape of the casing 10.
Figure 3 shows the finished shape of the intermediate product and its casing 10. Injection moulding has filled with plastic material all the slits 23 and 24 as far as the webs 28, including all perforations 31 shown in figure 1. The plastic material.finishes everywhere flush with the outer face of the system support 20 which was supported on the bottom half 40 of the mould, as figure 4 shows; this also particularly applies to the cross-sections of all the perforations 31. The plastic material of the casing 10 and the outside face of the system support's contacts 21 thus jointly form one side of the elec-tronic module, namely its flat surface 12 (figure 5).
The plastic material for the casing 10 should preferably be a duroplastic synthetic resin having a low coefficient of f-hArmal ovr,~n~y:~ .._i., ' . . .- -. r_. .., JuW a CiJ ~5 ycl,Craiiy known and used for em-bedding silicon chips, i.e. so-called low-stress material which contains a large proportion of quartz. By contrast, the. metal used for the system support 20 has a high coefficient of thermal expansion, and therefore expands in the mould because of the temperature of the injected plastic. Later, as the metal cools, it shrinks again and encloses the plastic that fills the perfo-rations 31 as it hardens, and thus produces a very strong com-pression fit of high density. This results in a mechanically stable bond between the metal parts and the resin of the casing, yet does not require the plastic resin to spread beyond the metal parts during injection moulding, nor the metal to be de-formed or machined in its thickness.
The profile of the thin, flat plastic casing 10 may be stepped in thickness, for example as indicated in figures 4 to 6, in which only the central area of the casing is the full thickness, where the plastic material envelops the chip 1 and wires 3 to form the casing's flat side 11 opposite the external contacts 21 and the flat side 12.
Once the plastic casing 10 is formed, as shown in figure 3, the intermediate product taken from the mould is then further processed as follows:
First of all, the module is cut free from the framework of the system support 20, along two symmetrical lines 32, only one of which is visible in fig. 3. At the same time, the webs 28 are punched out, except for a single web 28a (figures 3 and 6) which provides an electrical connection from the chip pad 22, via the bridge 25, to the external contact at top right in figure 1, and forms the ground connection for the module's cir-c~.titry. With the electronic module in this state, it is now suitable for electrical tests by means of its external contacts.
In the present case, where the module is to be integrated in a thin, flat plastic supporting body or medium, such as a chip card of credit-card shape and size, the metal lugs 26 and 27 are cranked or bent over all round the casing 10 along the bending lines 30, as indicated in figures 5 and 6. These bent-over por-tions extend toward the side 11 of the_module opposite to the system support; in the present example they extend for the full thickness of the module M, so that the ends of the lugs lie in the plane of the flat surface 11 of the casing opposite to that of the external contacts 21. Some of the lugs 26 and the two lugs 27 that lie opposite each other relative to the casing 10 are connected mechanically to the external contacts 21, and the other lugs 26 project from the two bridges 25 connected to the chip pad, as shown in figure 1. The perforations or windows 29 referred to above in connection with figure 1 are now in the zone where the lugs are bent over, as shown in figures 5 and 6.
The finished electronic module M shown in figures 5 and ' 6 is now ready for insertion in an injection mould made up of two halves 44 and 45, as shown in figure 7. At the ends of the two lugs 27, suitable openings 35 are provided which can be gripped by the grippers of an assembly robot. Next to these are centering holes 36 in which centering pins 46 of the injection mould engage, as shown in figure 7, to ensure that the module M
is accurately positioned for the chip card in the mould's void K'. Note that this positioning process is performed directly on the module's external contacts and not indirectly by way of the module's casing.
Generally, the lugs 27 of the system support 20 that project beyond the plastic casing 10 are designed to interact with automated assembly equipment used for handling the modules M. The gripper and/or positioning profiles 35, 36 of the modu-le's metal structure, for example shaped like those shown, lie in a precise positional relationship to the module's external contacts 21. This also ensures precise automated manipulation and accurate positioning of the modules, for example in test operation, packaging, etc. Use of a metal rather than a plastic structure and the relatively large offset between the profiles 35, 36 of the two lugs both ensure this high positioning accu-racy.
A thin decorative film 48 can be laid in the injection mould 44, 45, as shown in figure 7, against which the electronic module M then lies with its flat face 12 and external contacts.
The film used for this is usually printed in such a manner as to be suitable for a thermal transfer printing process, in which :: :a =rri~~tcu ima~c c:cn~bines only with the plastic injected in the void K' of the mould, but not with the metal parts of the elec-tronic module.' The film 48 is used to obtain a printed image on the face of the chip card by wellknown means. In the upper half of the mould 45 a label 47 covers the electronic module M. This is also printed and extends over the whole of the chip card for-mat. For making the chip card, injection of thermoplastic mate-rial, preferably ABS, into the void K' of the mould also uses techniques known per se. In this process, the plastic material is injected all round the edges of the module M, which becomes perfectly flush with the injected material of the card; the thermoplastic material passes through the windows 29 and late-rally between all the lugs 26, 27, and thus forms an extremely solid mechanical bond between the module's metal parts, espe-cially its external contacts, and the material of the card. It is note-worthy however that no thermoplastic material is used as a backing on either face of the module, i.e. the electronic module is of the same thickness as the thermoplastic material of which the card is made. In other words, the full thickness of the injected card material is available for the module casing 10; thus, for a given card thickness if 0.84 mm and a thickness of, say, 0.12mm for the label 47, the module casing 10 can be 0.72 mm thick.
The electronic module described above and other suitable embodiments thereof are also recommended for integration in other thin, flat plastic objects or supporting bodies, such as electronic keys. Generally, however, various other forms of in-tegration and~use are also possible, i.e. wherever a thin, flat type of module is necessary or offers special advantages, as for example in the assembly of components on printed circuit boards by the SMD (surface mounted device) technique.
Figures 8 to 13 show a further embodiment of an elec-tronic module of extra-thin construction and of its manufacture.
In this case, injection moulding of the module's casing and its integration in a card or other supporting body are similar as described above and not shown separately; cf. figures 4 to 7 and the related description set forth above. Many of the module's components in the embodiment of figures 8 to 13 are similar to those in the embodiment described above and thus have the same reference numbers.
The following differences apply to the system support 20' in figure 8: On the external contacts 21, the portions re-mote from the chip pad 22 are not connected to one another by webs, as items 28 in figure 1, but extend separately into the lateral margins of the system support 20'. The contacts 21 have no perforations such as 31 and 29; instead, lateral cutouts 29' are provided which lie on bending lines 30, as figure 10 indi-cates. On the bridges 25 that hold the chip pad 22, webs 16 connect the outlying portions to the system support, and slits 17 are provided oil both sides of the webs 16; these slits 17 are parallel to each other and to the contacts 21, and lie on further bending lines 30, as seen in figure 10.
Figure 9 shows the chip 1 mounted on the system support 20' and connected electrically by leads 3 to the external con-tacts 21. Chip 1 is again attached to the system support 20' by an insulating bonding film 2' that lies between them, but in this embodiment the film 2' extends beyond the area of the chip 1 as far as over the contacts 21, bridges 25, and slits 17. In particular, the film also covers all the slits 23 and 24 that form the boundaries of the chip pad and of the external contacts. The film 2' is typically made of tape material, such as polyimide, for example 50~m thick Kapton~ or Mylar°, and has holes die-cut or punched out before it is applied to the system support 20', as follows:
- two openings 5 that leave the webs 16 exposed;
- openings 6 for the passage of the wires 3 to the external contacts;
- a centering hole 7 which is brought in to coincidence with a corresponding hole 7', as shown in figure 8;
- an edge cut-out in the area of the sprue or stalk 42 that occurs in injection moulding of the module casing 10;
figure 9 shows 42 and 10 dot-dashed;
- if necessary, a hole 9 may be left in the area of the chip pad for connecting the underside of the chip to the system support by means of a conductive adhesive.
The thus prepared section of film 2' may be laminated to the system support 20', as described above for the adhesive film 2 in connection with figure 2. The chip 1 is then bonded to the adhesive film and the electrical connections are made, all similarly as described above.
In the present embodiment, the film 2' not only provides an elastic mechanical bond between chip and system support, but also has other functions: the adhesive film provides an intimate, large-surface connection between the adjacent contacts 21, the chip pad 22, and the bridges 25. In injection moulding of the casing 10 in a mould similar to that described and shown in figure 4, the film 2' stops the plastic material penetrating into the slits 23, 24 and under the external contacts 21 on the module's outer surface, i.e. it prevents the unwanted formation of so-called flashes on the outer surface. A film material and/
or adhesive coating used with some but slight electrical con-ductivity may be used for the effective attenuation of voltage peaks, for example due to electrostatic discharges that reach the external contacts, to provide so-called ESD protection (ESD
- electrostatic discharge); this is especially important in the case of chip cards, because the terminals of the integrated circuit, i.e. the external contacts, are exposed on the outside of the chip card and are insulated from one another. A further important function of the film 2' in the area of the slits 17 is explained below in connection ~~~ith figures 11 and 13.
~n ti~i5 second embodiment, the film 2' provides practi-cally the only, though indirect mechanical link between the casing 10 and the system support 20'. Experience has shown that adhesion'of the casing's plastic on the film 2', and of the film on the system support, is far greater than direct adhesion be-tween the materials of the casing and of the system support.
Hence the adhesive film 2' considerably strengthens the module M, and, in particular, it effectively prevents the external contactslbecoming loose or pulled out from the chip card's sur-face. Conversely, after injection moulding of the casing 10, the sprue or stalk 42, which forms directly on the metallic surface of the system support, is easy to remove from its metal sub-strate and to break off at the edge of the casing.
Figure 10 indicates that when the module has been taken out of the injection mould for making the casing 10, and after removal of the sprue or stalk, two symmetrical surfaces 14 are punched out from the system support 20', while the module is still held by its two webs 16. This cutting-free operation severs the contacts 21 on the outside, but they still remain attached to the casing 10 via the adhesive film 2'. The profiles of the lugs 27 are shaped in the same punching process, and a hole 35 can be punched out at the same time in the upper lug 27, the sprue or stalk 42 having been removed. In the same opera-tion, four lugs 34 are also punched out on both sides of the two webs 16 near the slits 17.
-im d mexi step, a bending tool bends over the projecting portions of the system support's metal strip, along the bending lines 30 on the edges of the module, whereby the webs 16 are left flat and hold the module attached to the system support.
Finally, a further punching tool also trims off the webs 16 and thus releases the finished module bi from the system support 20'.
The modules M made in the fully automated manner as described above and shown in figures 11 to 13 can then be inte-grated in a chip card or other support by an injection-moulding technique similar to that described earlier by reference to figure 7 for the first embodiment. As regards reliability of fixation etc, essentially the same characteristics and features are obtained. The plastic material of the supporting object is likewise injected around the edges of the casing 10 and bonds to the flat surface surrounding the module casing 10, which is covered by the film 2', and likewise to the bent-over portions 26', 27, and 34, as will be easily recognized from figures 11 to 13.
Finally, figure 13 shows the additional function of the film 2' which is drawn across the slits 17, as brief reference has already been made. During injection moulding of a supporting body or object, such as a chip card, the plastic material pene-trates into the slits 17 but remains separate along the slits due to the film 2'. This provides a useful hinge effect along the slits 17 that can to a large extent cope with the stresses produced when the card is bent, and thus further protects the module M and the chip 1 from damage due to excessive bending of the card. It would also be feasible, if necessary, to use the same means in respect of the lugs 26' and 27, i.e. by providing further slits in that areas and extending the film 2' past these lugs and the zones where they are bent over. In the case of chip cards, however, because of the established standard layout of the module M caithin the rectangular card format, the bond be-tween the lugs 34 and the card's material is subjected to far greater bending stresses than the corresponding bond at lugs 26', 27.

Claims (7)

CLAIMS:
1. An electronic module of flat design, having outer contacts which are joined with a plastic housing and formed by a system support member in the form of a flat sheet-metal structure, and having a semiconductor chip mounted on the system support member and embedded in the plastic housing, the system support member being provided with lugs projecting beyond the plastic housing and having engaging and/or positioning contours which have a well defined position vis-à-vis the outer contacts of the electronic module and which are designated for cooperating with automated assembly machines.
2. The electronic module according to claim 1, having two lugs which are arranged on two opposite edges of the plastic housing.
3. The electronic module according to claim 1, wherein each of the lugs emanates from an outer contact, has a right-angled bent of the height of the plastic housing outside the plastic housing, and has its end situated on the plane of the plastic housing's outer surface opposite the outer contacts.
4. A chip card, specifically a credit card, comprising a plastic body made from an embedding compound and containing an electronic module according to claim 1, wherein the thickness of the embedding compound is equal to the thickness of the electronic module.
5. Electronic module of extra-thin construction, having external contacts bonded to a plastic casing and made out of a system support formed of a thin, flat metal-strip structure to which is fitted a semiconductor chip surrounded by said casing, characterized in that said support has lugs outside the plastic casing, which are adapted for interaction with automated assembly equipment and are formed with gripper and/or positioning profiles arranged in a precise positional relationship to the external contacts of the module.
6. Electronic module according to claim 5, characterized by two lugs which each project beyond one of two opposite edges of the flat plastic casing.
7. Electronic module according to one of claims 5 or 6, characterized in that each of the lugs extends outward from one of the external contacts, is bent over or cranked outside the plastic casing over the thickness thereof, and whose end extends to the plane of a flat surface of the casing opposite the plane of the external contacts.
CA002206786A 1992-11-27 1993-11-23 Electronic module of extra-thin construction Expired - Fee Related CA2206786C (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
CH363392A CH686325A5 (en) 1992-11-27 1992-11-27 Electronic module and chip card.
CH03633/92-9 1992-11-27
CA002109761A CA2109761C (en) 1992-11-27 1993-11-23 Electronic module of extra-thin construction

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
CA002109761A Division CA2109761C (en) 1992-11-27 1993-11-23 Electronic module of extra-thin construction

Publications (2)

Publication Number Publication Date
CA2206786A1 CA2206786A1 (en) 1994-05-28
CA2206786C true CA2206786C (en) 2001-07-03

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
CA002206786A Expired - Fee Related CA2206786C (en) 1992-11-27 1993-11-23 Electronic module of extra-thin construction

Country Status (1)

Country Link
CA (1) CA2206786C (en)

Also Published As

Publication number Publication date
CA2206786A1 (en) 1994-05-28

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