DE19932960C2 - Method for producing a chip card module, positioning device for carrying out such a method and positioning method - Google Patents

Description

The invention relates to a method for producing a Chip card module with a semiconductor component, which with an inductive signal transmission arranged in the card device in the form of an antenna coil can be contacted according to Preamble of claim 1 and a positioning direction for performing such a method and a Positioning procedure using the positioning device tung.

It is known from the prior art during production a chip card, especially one that has means of contact have loose data transfer into a card body Insert module, which comprises a semiconductor chip.

This separate module with semiconductor chip is preferably in a cavity or recess is inserted in the card body and by means of joining or the like with the card body while receiving an appropriate mechanical and electrical Laminated connection. For example, an electrical Connection between module and card body or on the Contacts located on the card body with a coil Establishing a contactless connection to the environment in Stand in contact because anisotropic conductive adhesive in the area of the connection points and / or the  Connection points of the respective agent for a contactless Data transfer applied and the adhesive at least in Area of the connection points compressed or compressed as far is that an electrically conductive bridge is created.

The modules used in the production of chip cards usually fall back on a plastic carrier on which the aforementioned semiconductor chip with contact areas is provided. The prefabricated ISO module is with the card carrier z. B. can consist of polycarbonate, connected. This connection or the onset of the complex Module in the card body in one, for. B. milled recess usually takes place using the aforementioned adhesive procedure when using a hot or hot melt adhesive.

The chips are chip-contacted after separation on the module tiert, wherein the module said contact surfaces to the Her make external electrical connections. About one Wire bonding processes are the contact areas of the chips with the Module contact surfaces connected. Then it is available Avoid damage to the module provided with to complete an encapsulation.

The sequential process steps for manufacturing the module with a semiconductor chip, however, are very time and cost intensive, with the sandwich-like structure of the so designed Assembly certain dimensions both laterally as well as the minimum thickness can be.

However, because the chip card or the card carrier or cards body as thin as possible, but at the same time over sufficient stability with regard to bending and other stress cycles should result here essential problems in the desired further development of the State of the art.  

DE 44 16 697 A1 discloses a data carrier comprising one Card body, an integrated circuit that is electrical conductive via contact elements with at least one coil is bound, the energy supply and data exchange of the Integrated circuit with external devices is known.

According to the solution there, the integrated circuit and the Contact elements a separate module known per se, the Coil on a one or more layers Card body is arranged. The integrated ones used there Semiconductor components are in the card body before assembly separable, each have a lead frame on the active page send modules. The leadframe has large outer cones clocks for connecting the wired or laminated ge punched antenna coil.

A carrier element for installing a chip card with a a leadframe conductor carrier arranged and with its Kon clock flags electrically connected semiconductor chip shows the DE 44 31 754 C1.

A so-called hybrid chip card is known from US Pat. No. 5,598,032 knows which for both the contact and the con tactless data transmission is suitable. In a recess of the Card body, a chip module is used there, with the Effectiveness of the connection of an antenna coil to the wire the data of the contacts one loose if possible have maximum size.

According to IMB Technical Disclosure Bulletin, Vol. 22, No. 6, November 1979 , pages 2336, 2337, it is known to thin the back of a semiconductor chip in order to use it in chip cards, which in turn are small in thickness and have a cavity Have depth.

The unpublished DE 197 16 342 A1 describes a special process for producing a  Chip card, bond pads being present in the disc assembly Comprehensive, thinned back transponder semiconductor construction elements with a weldable and / or solderable metallization or contact bumps in the area of the bond pads. This is followed by the procedure there, with the exception of Contact areas a passivation of the transponder semiconductor Components. A lead frame is then placed on the window dressing Compound in wafer size fits exactly to the active contact adhered side of the semiconductor devices arranged and with the Contact areas electrically connected. The leadframe network shows single leadframes with a size of at least two each flat antenna contacts. After the con The assembly obtained in this way is a single connection undergo in leadframe chips and these single chips are then in corresponding recesses in the card body or card carrier introduced and the required connection between the leadframe antenna contacts with the contacts of the antenna nenspule, which is embedded in the card body made.

However, it has been shown that with such a solution the made electrical connections between leadframe and Contact bumps using micro-welding are extremely time-consuming are agile, resulting in bottlenecks in technology put. In addition, the effort for separating the Chips due to cutting the leadframes along the Partitions between the chips on the substrate large and it there is a risk that working with micro or Diamond saw Micro cracks in the wafer or substrate are created with the As a result of a reduced yield or worsened Lang time stability of the modules manufactured in this way.

It is therefore an object of the invention to produce a method development of a chip card module with a semiconductor component to indicate which one with an induc tive signal transmission device in the form of an antenna coil can be contacted, the method being particularly effective, be feasible according to the technological cycles should.  

Furthermore, it is an object of the invention to provide a positioning direction for performing the method and a positioning to specify the method by means of which particularly thin sheets Similar lead frames in wafer format related to the active ones Components carrying wafers can be moved and fixed.

The object of the invention is achieved on the process side with a solution according to the teaching of claim 1, bezüg Lich the positioning device with an object according to the Features of claim 6 and with a view to the position kidney method with a teaching as defined in claim 7 is.

The subclaims include at least appropriate configuration lines and developments of the invention.

The basic process concept for the production of a chip card module is that in a manner known per se from present in the disc association, including bond pads, too thinned back semiconductor semiconductor components is, which with a weldable and / or solderable Metalli tion or contact bumps in the area of bond pads are provided. Furthermore, a leadframe composite in wafer size is provided and this fits exactly on the active, contact-side the semiconductor devices arranged and with the metallization or electrically connected to the contact bumps. According to the invention the metallization or the contact bumps by applying an isotropically conductive adhesive using a template in the Slice format practically simultaneously. The leadframe network has special contacting cutouts and a back side adhesive coating, whereby the leadframe composite to Wafer is positioned that the metallization or the Kon exposed bumps of the wafer. An adhesive print on the wa fer is also conceivable.

After the leadframe has been positioned with respect to the An contacting recesses, d. H. based on the disks bonded, a curing of the adhesive of the back coating  to fix the position between the wafer and the leadframe performed.

Following this. It is fixed in the area of contact a contacting material, which in a subsequent thermal process becomes a Simultaneously occurring electrical contact between Semiconductor device and leadframe leads. In a preferred one The alternatives are the thermal process step existing solder paste contact bumps almost simultaneously melted and it becomes over capillary and adhesive forces the electrical connection between the contact bumps and the corresponding contact area of the leadframes with the solidification reached the solder paste.

The chip card modules are then separated along of target dividing lines, which also means that the required isolation of the lead's large-area antenna contacts frames.

In one embodiment of the invention, before application the solder bumps in the corresponding area an intermediate metallization made.

An Invar leadframe with galvanic deposition is preferred ner silver coating used.

A special one is used to print the solder bumps on the wafer Laser template used, the contact window a for example, have a square shape. The diameter of the solder paste bumps applied by screen printing is about 195 µm.

The metallization or the solder bumps are compared lying corner area of the chips of the disc association forms and the wafer leadframe comprises corresponding ones Contacting cutouts per chip. With the ecxeption of Stabilizing bridges are along the leadframe  of the chip dividing lines with further separating recesses, so that easier separation is possible.

Of course there is the possibility of the adhesive coating also to fix the leadframe in the pane to selectively apply to the surface of the wafer or one Place the film on the solder bumps this is then pierced when the lead frame according to position nation is pressed.

The particular advantage of the method described is that that the semiconductor devices simultaneously to the contact areas of the leadframes can be micro-connected, making Ferti time can be saved. Covered by the long side on the isolated chip in the leadframe, along the Cutouts running in chip separating lines is the singling in shorter time and with less mechanical energy possible, which in turn makes the use of ultra-thin substrates possible.

The isolated chip card module is included with the lead frame large contacts, almost with the exception of an isolie covering the entire active area, already protected, which makes the leadframe housing function Fulfills.

The positioning device according to the invention for implementation The method described above is based on a print job beatable membrane stamp, with the membrane stamp on its flexible holding surface coated with an adhesive is. The flexible holding surface is essentially one rigid network spanned.

The holding surface can be the leadframe, which is a thin has a leaf-like structure, pick it up and move it. The flexible deforms by slightly increasing the pressure Stamp membrane through the essentially rigid network and touches the lead frame. By means of the adhesive coating it is now possible to hold the lead frame and this with the help  to move a mechanical transport device. This Movement takes place towards the wafer, whereby on the basis of Positioning marks prefer an optical alignment in the three axes of a Cartesian coordinate system or Angular alignment is made. The lead frame is then included Using the membrane stamp, the internal pressure of which is increased and whose holding surface bulges out onto the surface of the wafer. An appropriate adhesive coating then allows fixation by the wet adhesive strength of the adhesive of the leadframe on the wafer. By reducing the pressure in the Membrane stamp pulls in the adhesive-coated film the openings of the rigid mesh back, whereby the Leadframe is released.

It is understood that with the help of the positioning device not just pressure on the leadframe towards the wafer for the better Adhesive fixation can be exercised, but that by alternately bulging and pulling back the membrane or Holding surface to pick up and release and thus positioning of the leadframe is easily possible.

Accordingly, a structured, sheet-like, very thin, flat material in the form of the Lead frames taken from the holding surface of the membrane stamp and this into a flat substrate, namely the wafer emotional. After appropriate positioning is reached with the end position by increasing the pressure in the membrane stamp Holding surface arched outwards and thereby a force exerted on the leadframe and the wafer through the net, so that there is an intimate connection between leadframe and wafer results. After at least partial curing of the adhesive a membrane pressure reduction is carried out, whereby the flexible holding surface bulges inwards, d. H. moved back.

The invention is illustrated below with the aid of an embodiment game and explained with the help of figures become.  

Here show:

Fig. 1a a section of a laser mask for solder printing,

FIG. 1b formed solder bumps by printing thereof,

Fig. 1c shows a 6 "wafer with printed solder bumps,

Fig. 2a shows a Invar leadframe with galvanic silver coating positioned on a wafer,

Fig. 2b shows a detailed view of a leadframe positioned on a wafer with recognizable contacting cutouts and solder bumps as well

Fig. 3 is a schematic sectional view of the Positioniervor direction on the basis of a flexible membrane stamp.

The process flow for a wafer level packaging according to Ausfüh Example starts with a design to be created for the contact structure of the leadframe. This is followed by if necessary, a surface metallization of the front and an adhesive coating on the back of the lead frame and an optical inspection is made.

The 5 to 8 "wafers containing cycle 1 semiconductor devices, are subjected to a wafer mapping and a Embodiment before forming the solder bumps by screen printing with the help of e.g. B. a screen printing mask Underbump metallization made. Following this Steps will also be optical and / or electronic Inspection of the wafers made.

The prefabricated leadframe in wafer dimensions is then exact positioned on the wafer and it takes place Bonding and thermal curing of the composite. Subsequently  the contact between the solder bumps on the one hand and initiated the later antenna contact areas of the leadframes, this can be done by a temperature process at which is the electrical connection by the course of the Lots in connection with adhesion and capillary forces established.

A cut-off of the chip is then carried out along the chip separation line Wafers, i.e. H. a separation made in chip card modules.

Fig. 1a shows a section of a laser template in a thickness of about 150 microns with square contact windows. The formed solder bumps with a diameter of essentially 195 μm by stencil printing using the laser stencil are shown in FIG. 1b. A finished 6 "wafer with printed solder bumps can be seen in FIG. 1c.

The Invar leadframe with an electrodeposited silver coating according to FIG. 2a is produced on the same disk scale.

The leadframe contains a variety of contact areas, which when using the chip card module the connection to a Enable antenna coil.

The detail representation according to FIG. 2b shows solder bumps 2 formed in the corner regions of the chips 1 which are still present in the wafer bond. In addition, the contacting cutouts 3 and the subsequent antenna contacting areas 4 of the lead frame can be seen.

Along or above the chip separating lines 5 , 3 further recesses 6 are formed in addition to the contacting cutouts, so that the chip card modules can be separated and separated easily.

The contacting, ie the establishment of an electrical connection between the antenna contact surfaces 4 and the solder bumps 2 while overcoming a free section of the contacting recesses 3, takes place in a thermal process in which the solder of the bumps is melted and this solder capillary to the corresponding one Leadframe section runs. Additionally or alternatively, there is the possibility of applying contact material via a corresponding mask and subsequent temperature process.

The advantage of the above-mentioned embodiment is in that the entire wafer composite on the contacting side is treated together, so that manufacturing time is saved can be and thereby an improvement in technology overall becomes possible.

With the help of FIG. 3, the positioning device for performing the disk-bandaging contacting method will be explained in more detail.

It has been shown that it is problematic, a Invar lead frame with a leaf-like, thin structure precisely record, move and move on a semiconductor wafer position.

The positioning provided to solve this problem direction consists of a pressurizable membrane stamp with an area which is at least the wafer or lead frame size corresponds.

Via a pressure feeding means 7 is a flexible retaining surface (ram side) 8 both when the pressure increases outwardly wölbbar as retractable even when pressure reduction inwardly into the meshes of a net. 9 The downward curvature caused by the weight of the lead frame can be compensated for by an appropriate pressure reduction.

The holding surface 8 is coated on one side with an adhesive material. The essentially rigid net 9 is arranged between the underside of the stamp and the non-sticky back of the holding surface.

In use, the membrane stamp is moved over the leadframe 10 and, by increasing the pressure in the interior 11 and resulting bulging of the flexible holding surface 8, the leadframe is picked up by the adhesive when the surfaces are touched.

After recording, the lead frame can be shared with the flexible membrane stamp moved, e.g. B. a semiconductor wafer spent and aligned or positioned there.

After lowering the membrane stamp in the desired position this lies on the surface of the wafer (not shown) and an adhesive coating is used to connect Lead frame and wafer.

By further increasing the pressure in the interior 11 , a defined pressure or pressing force can be applied in a uniformly distributed manner to the lead frame or the wafer located underneath and the adhesive intermediate layer.

In order to detach the leadframe 10 from the membrane stamp, the pressure in the interior 11 is reduced, as a result of which the flexible holding surface 8 bulges inward into the mesh openings. The rigid network 9 acts in this case as a counterhold. The adhesive area to the lead frame is reduced so that it easily detaches from the device or is stripped off. The release of the leadframe does not affect the accuracy of the storage position due to the given symmetrical geometry.

It is in the sense of the embodiment that by changing sequence of pressure increase and pressure decrease as well as intermediate movement steps a micro position between a substrate and one of the membrane stamped lead frame or similar part possible is.  

REFERENCE NUMBERS

1

chip

2

Lot Bump

3

Ankontaktierungs recesses

4

Antennenkontaktierungsflächen

5

Chip dividing lines

6

recess

7

Pressure feeder

8th

flexible holding surface

9

network

10

leadframe

11

inner space

Claims (10)

1. A method for producing a chip card module with a semiconductor component which can be contacted with an inductive signal transmission device arranged in the card in the form of an antenna coil, with the bond pads comprising semiconductor components with a weldable and / or solderable one being present in the disc assembly Metallization or contact bumps in the area of the bond pads are provided, furthermore a leadframe composite in wafer size is arranged with a precise fit depending on the active, contact-side of the semiconductor components and is electrically connected to the metallization or the contact bumps, the leadframe composite in each case individual lead frames with at least one has two large-area antennas contacts, characterized in that
the metallization or the contact bumps are formed quasi simultaneously using a template in disk format;
the leadframe composite has contacting cutouts and a rear-side adhesive coating, the leadframe composite being positioned on the wafer in such a way that the metallization or the contact bumps are exposed;
after positioning, the adhesive of the back coating is cured to fix the position between the wafer and the leadframe;
Subsequently, contacting material is applied in the area of the contacting recesses, which enables simultaneous electrical contacting between the semiconductor component and the leadframe in a subsequent thermal process, and / or the solder paste contact bumps are melted via a thermal process step and via capillary and / or Adhesive forces result in an electrical connection to the leadframe with solidification of the solder paste; and
that the chip card modules are separated along predetermined separation lines, thereby simultaneously isolating the large-area antenna contacts from one another. 2. The method according to claim 1, characterized in that to improve handling during machining in Disc association of a thinned wafer with this on the back a temporary stiffening membrane or layer becomes. 3. The method according to claim 1 or 2, characterized in that the wafer before applying the solder bumps in this area is provided with an intermediate metallization. 4. The method according to any one of the preceding claims, characterized in that the adhesive coating is also applied to the wafer. 5. The method according to any one of the preceding claims, characterized in that the metallization or the solder bumps in the opposite Corner area of the chips of the disc association are formed and the wafer leadframe in each case corresponding contact tion cutouts per chip, with the exception of stabilizing connecting bars along the chip dividing lines To make it easier to separate them later, largely cut-out conditions are provided. 6. Positioning device for performing the method according to one of claims 1 to 5, marked by a pressurizable membrane stamp, the membrane stamp on a flexible holding surface with an adhesive  is coated or consists of such a substance and flexible holding surface of an essentially rigid network is under tension, with a pressure supply device a change in the curvature of the holding surface from concave to in Interstices of the suction area sucked in and around is possible. 7. positioning method with a device according to claim 6, characterized in that a structured, sheet-like flat material in the form of a leadframe picked up from the holding surface and to one flat substrate in the form of a wafer moves and positio is niert, after reaching the end position by pressure increase in the interior of the membrane stamp over the holding surface a defined force can be exerted on the leadframe and the wafer so that there is a direct adhesive connection between the leadframe and wafers can be manufactured and after a membrane The flexible holding surface in the net reduces pressure gaps moved back and the leadframe from the wet glue force or initial adhesive force is retained to the wafer. 8. Positioning method according to claim 7, characterized in that by increasing and decreasing pressure on the stamp membrane and relative movement between stamp and substrate or Wafers of the leadframe picked up, positioned and stored becomes. 9. Positioning method according to claim 7, characterized in that by selecting the adhesive coating of the holding surface Adaptation to different initial adhesive forces of the assembly adhesive takes place.   10. Positioning method according to claim 7, characterized in that an adjustment by selecting the mesh sizes of the network different structure sizes of the lead frames occur.