Carrier film for chip modules which is adapted for automatic control of wiring and method of manufacturing chip modules

p0001The present invention relates to a support film for the electronic module. It also relates to a module manufacturing process employing the flm carrier. The invention is applicable to any substrate and method in which a chip is connected to a substrate.

p0002Such film supports are used particularly in the manufacture of electronic chip module used in the smart canes composition and / or printed circuits. The invention is directed to two-sided type of film media comprising in particular an insulating end dielectric film in plastic or polymeric material having a dielectric glass / epoxy. The thickness of these films is about 75 microns, however, any insulating substrate carrying metallizations to be connected is concerned by the invention and therefore equivalent to a support film.

p0003A strip or module supporting film comprises a plurality of modules, an electrolytic growth process used in obtaining the support film, requires to have the ranges of metal contact all interconnected, thus short-circuited. By cons, for the module is functional, these beaches are all to be made independent. Generally, this operation Décourt circuiting is performed in a film-support provider. It is to perforate or cut out areas where all the tracks are interconnected by one place.

p0004During a wiring operation of an electronic component such as an IC chip, on a substrate comprising metallizations for connecting the electronic component used is an automatic connection and simultaneous control of the connection. The connection is made in particular by welding technique son overhead conductors (wire bonding).

p0005The quality of the welding wire and / or quality of the wired connection is continuously monitored during the connection. This is followed by an electrical test by measuring the impedance / voltage between the wire and ground equipment (NSD system), the metal surface receiving the solder being put at a predetermined potential during the test. For this, the machine needs a reference potential connected to the ground of the machine. However, after Décourt circuiting, all contacts are independent and the reference potential is hard to find: it assumes that at least one of the contact areas is connected to ground machine, which is not always the case as explained below in the description of the figures with reference to<figref idrefs="f0001">figure 1</figref>. The reference potential is hard to find because the contact resistance varies depending on the geometry of each contact. It is actually difficult to maintain a multitude of small metal parts as in the case of statically indeterminate system.

p0006This results in quality assessment errors connections of modules that can be put in wrongly discarded.

p0007The invention aims to solve the aforementioned drawbacks. It aims to provide a module-supporting film which is particularly suitable for quality control of wire welds to connect the chip to the beaches or electrical contacts of the holder.

p0008The solution is in principle to carry out a partial Décourt circuiting, especially not Décourt-circuit one of the contacts (that of the mass of the module) thanks to a particular configuration of the module and the tracks connecting the electrical contact pads between modules on the supporting film.

p0009This does not disturb the assembly process and in no way prevents the operation of the module, but solves the problem of contact with the frame: in fact, There will always be on the frame of the length (several dozen centimeters) at least one point of one of the frame in contact with the modules, which allows the system to detect any wiring problem.

p0010If the mass of the film is in contact with the frame and if the first cable wire is grounded, we get a stable power configuration for all the chips and detection of good / bad weld can then perform normally over the reference measurement previously learned by the machine on which it is based to determine poor connections.

p0011To this end, the invention firstly relates to a module-support film for an electronic device, said film carrier comprising an insulating film and a plurality of patterns arranged on the insulating film, each pattern defining the metal contact pads corresponding to a module;

p0012It differs in that the contact pads of each module for connection to a component are Décourt-circuited with the exception of a contact pad which is connected to at least an equivalent contact pad of another module by a conductive track.

p0013According to a preferred characteristic, said contact pad constitutes an electrical ground (g) of the module.

p0014The invention also relates to a method for manufacturing an electronic module, said method comprising the following steps:<ul><li>supply or realization module-support film for an electronic device, said film carrier comprising an insulating film and a plurality of patterns arranged on the insulating film, each pattern defining the metal contact pads corresponding to a module,</li><li>postponement of an electronic component on the support film and component wired to the contact areas with a machine having a frame to ground and a coil of conductive wire, said machine performing the wired connection and a quality control measure potential between the wire or wire coil and the mass of the frame;</li></ul>

p0015The method is characterized in that the module-supporting film is already provided with the features mentioned above or in that the method comprises a step prior to the component connection whereby each module contact pads intended to be connected to a component, are Décourt-circuited with the exception of a contact pad (g) which is connected to at least an equivalent contact pad of another module by a conductive track.

p0016In this way, it is ensured that the area can be connected effectively grounded the machine and proper control can perform wiring and avoid disposing of good modules.

p0017Other characteristics and advantages of the invention will appear on reading the detailed description which follows and which is given with reference to the accompanying drawings, in which:<ul><li>the <figref idrefs="f0001">Fig. 1</figref> illustrates a sectional view of a connecting operation and simultaneous test of the prior art wiring implemented by the invention;</li><li>the <figref idrefs="f0001">Fig. 2</figref> illustrates the object of the <figref idrefs="f0001">figure 1</figref> view from below;</li><li>the <figref idrefs="f0002">3</figref> illustrates the process of the invention according to an exemplary implementation.</li></ul>

p0018To the <figref idrefs="f0001">figure 1</figref>, Integrated circuit chips 1 are arranged on an insulating support 5 and during connection and wiring test with a head 3 of machine (M) adapted for this purpose according to a failure detection system wiring (NSD), acronym of the English expression "non stick detection" system that measures the potential between a machine frame mass and a coil of wire (or wire) and thereby measure the impedance of the electrical assembly comprising the integrated circuit, the wire and the support film.

p0019contact pads 7, 8, 9, 10 all independent are arranged on the other side of the film and are based on a metal plate 11 of a machine or production modules station; contact areas are in ohmic contact with the metal plate 11 is grounded.

p0020In operation, the head 3 performs, for example, first a welding wire passing through the head on a contact pad 10 through perforation 12 of the carrier film then connects a pad 13 of the chip and makes a test potential of the wire 14 before it is severed. 10 being correct wiring, the potential Uz measured is zero. However, it can adopt a reverse stranding order, starting with cabling machine wire pad on the chip then ending with the welding wire on the carrier film

p0021For cons, the wiring 15 is performed correctly but the test machine will detect a positive potential and thus diagnose connection problems leading to depart this module as defective. This failure stems in the case of an absence of contact of the track 9 connected with the plate of the machine which is grounded. The absence of contact may be otherwise caused for example, a flatness defect of the module-supporting film, or an insulating debris on the tray.

p0022On the other contact 16 really defective because not formed on the contact pad, the machine will detect a positive potential Uz and therefore the same fault. To date, and this is the problem of the invention, as it is not possible to differentiate between connections 15 and 16, it is necessary to dispose of the modules in good condition.

p0023To the <figref idrefs="f0001">2</figref>, There is shown a portion of support film 16 of electronic modules according to one embodiment of the invention. The support film is generally in the form of film or dielectric elongated coil having metallizations on one side and / or both sides. The support film is also commonly referred to band module or substrate module and constitutes a complex as previously insulator / conductor comprising surfaces and / or electrically conductive tracks on an insulator.

p0024Metallizations define several units of identical contact pads arranged in series on the insulating film 17 and each pattern corresponds to a module. In the example, the figure shows four modules of the same pattern which comprises new metal surfaces (a, b, c, d, e, f, g, h, i, j) connected to different conductor tracks. These metallizations are obtained for example by electrochemical etching or by laminating against a metal band blank on a dielectric film.

p0025The film may comprise edge perforations 18 for driving the support film on the production machines. The support film is laterally bordered by at least metallized edge strip arranged around the perforations and extending continuously over the longitudinal edges of the support film.

p0026In accordance with one embodiment of the invention, each module contact pads are Décourt-circuited by punching some locations 21 except for a contact pad (g) of each module which is connected to at least similar contact pad (g ') of another module by a conductive track 22 located in an interconnection area 23.

p0027Preferably and in the example, the range of non Décourt-circuited contact (g) is an electrical ground of the module. If appropriate, other non-functional or unnecessary contact pads on the chip connection (a, f, e, j) can remain shorted to ground while connecting to the electronic component. For example in the module, the four outer boundary contact pads of the module are set at the same potential as the ground contact. If necessary the reasons are not identical but related sets beaches are either equivalent or even functional nature.

p0028In the example all modules are interconnected by their weight range (g) but it is sufficient for two reasons at least are interconnected. They may be adjacent or far apart, but it is preferred that both are present against the machine bed during the wiring test or one of the two. However, when wiring is performed simultaneously on four to eight modules, it is sufficient that one of the four or eight modules contacts the tray, which increases the chances of having at least a portion in contact with the built.

p0029Advantageously, by selecting the contact area corresponding to the mass as interconnection pad (g) between the modules, it is possible, after connection, to directly test the component despite the fact that the modules are connected at least to two. For safety, said contact range can be also connected by a second metal track to at least one web side of supporting film. The training wheels and / or clips of the film carrier also a mass may be considered by the machine wiring and associated test.

p0030The <figref idrefs="f0002">3</figref>Illustrates a method for producing an electronic module according to an embodiment of the invention:<ul><li>During a first step 100, there is provided a support film according to the above example but having all the contact pads shorted. This shorting is particularly useful to carry out or complete electrochemical metallization or etching;</li><li>At step 200, called Décourt-circuiting, the contact areas (a, b, c, d, e, f, h, i, j) are made electrically independent; This operation is performed for example at a support film supplier; The contact pads are disconnected with one another, disconnected from the banks of sidebands, if they exist, with the exception of contact pads (g, g ') representing the mass of modules which remain connected all together; Optionally, they can also remain connected to the strip edge; This can be done by cutting or punching a localized area of ​​a few square millimeters in particular at locations 21 collecting connection tracks to the electrical contact pads; This partial Décourt circuiting must be completed before the connection of the chip according to the teachings of the invention;</li><li>At step 300, it performs a delay of at least one electronic component 1, on the support film at the location of each pattern of contact pads; The transfer can be performed on the insulator or on a metal surface;</li><li>then place in the toulée connect components to the contact pads by lead bonding (called wire-bonding, or "edge bonding") with a machine (M) wired and wiring test as described above; One possible coating material with mechanical protection can be done then.</li><li>At step 400, a function test can be carried out and / or personalization of the integrated circuit itself separate from the wiring test operation;</li><li>At step 500, the user can immediately perform an extraction of the carrier film modules by cutting / punching around its electrical contact pads; extraction has the effect of removing the existing residual short circuit between the ground contact areas and remove residual connections of the tracks; If necessary, this step can be carried forward, the coils being stored and with a slip sheet.</li><li>At the final step 600, is performed in a inserting a chip card body.</li></ul>

p0031The resulting module can be an electronic device itself or be integrated for example in a holder in particular by insertion in step 700 or in any other device in subsequent steps for forming an electronic device comprising this module.