DE3219055A1 - Method of fabricating a film carrier having conductor structures - Google Patents

Abstract

The method makes it possible to use an annular support of the conductor strips of a film carrier in the terminal region of the semiconductor chips. By applying the annular pattern by screen printing, a thickness can be chosen which is less than the height of the terminal points of the semiconductor chips, said terminal points being designed as bumps. It is thus possible to protect the conductor strips with the annular pattern in such a way that the latter is situated between the conductor strip and the semiconductor chip.

Description

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Telefonbau und Normalzeit GmbH, PO Box Hh 32,

600C Frankfurt / Mair,

Process for the production of a film carrier with conductor structures

The invention relates to a method for producing a film carrier with etched conductor structures for integrated circuits with connection points lying on the surface of the chip, to which the conductor structures can be connected, the conductor structures being held in the vicinity of the connection points by a common insulating ring, which the integrated Circuit enclosing. For certain applications, for example for the production of hybrid circuits in thick or thin film technology, the integrated circuits in the form of semiconductor chips are attached to a film carrier at certain intervals electrical connections. For this purpose, the film carrier is provided with a copper foil into which a corresponding conductor structure is etched. The conductor structures are generally more or less radially shaped, with the individual conductor track strips increasing in size towards the outside. At the narrow end of the respective conductor track, the connection is made to the integrated module or chip, while the later connection to the substrate of the thick or thin-film module takes place at the broad end. The pre-fermenters described are also referred to as so-called film bonding, which is described, for example, in the publication "Electronics 1979, Issue H, on pages 39 to M2.

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In the connection area of the integrated circuit, the conductor structures are designed as narrow conductor strips. To Err.öhur.g the mechanical stability of the same, to adhere to the spacing of the conductor strips determined by the position of the connection points on the chip and to avoid them of short circuits between them, these are supported by an insulating layer, for example the insulating film carrier itself. The endeavors go there, this support as far as possible to the actual Let the connection point work. However, this is opposed to the layer thickness of the film carrier, since it is much greater is than the height of the al3 connection points formed on the semiconductor chip. From production engineering For reasons, the manufacturers of such semiconductor chips endeavor to give these bumps only one for later contact production ^ Thermocompression) to give the required height.

It is also possible to place the stool required to achieve a corresponding distance at the connection point to the To attach ladder strips yourself. The additional work steps required for this, however, do not allow any economic ones Production.

The object of the invention is now to provide a method for producing a film carrier with etched conductor structures specify for integrated circuits, in which on such, formed with a particular height as a hump Connection points both on the semiconductor bit chip itself and on the conductor strip can be dispensed with.

This task is solved by the following process steps:

1. Application of an annular pattern from a plastic compound in the area of the conductor structures to be supported by screen printing on a copper foil.

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2. Burning in the screen print

3. Etching out the conductor structures

■ 05 ^. Refining

It is assumed that the film carrier itself

is formed by the copper foil. Through the screen printing ; any pattern can be moved in any

Apply 10 different strengths to the copper foil.

(I A further development of the invention is provided by the following

.5 driving steps marked:

■ 15 1. Application of a ring-shaped pattern from a '! Plastic compound in the area to be supported

of the conductor structures by screen printing on a) copper foil

; 20 2. Burning in the screen print

*> 3. Gluing the copper foil to an insulating,

1 film carrier having openings such that the

% Pattern face down in the openings

4. Etching out the conductor structures

5. Refining

• i 30 If an insulating film base is used, it will be

* Provided with the corresponding openings, whereby afterwards

% on the same the copper foil is glued, namely the

I kind of screen printed the pattern down

[j lie in the openings.

I Further advantages result from the subclaims.

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The invention is explained in more detail using an exemplary embodiment which is shown in the drawing.

It shows

1 shows the individual process steps,

Fig. 2 shows the formation of the individual conductor strips and their support for

the connection of semiconductor chips with connection points, which in several parallel rows are arranged and

"Fig. 3 shows a cross section through one on one

Semiconductor chip attached to the substrate and its electrical connection.

With reference to Fig. 1, the method according to the invention is both for film carriers, which are made of an electrically conductive Material as well as those made of insulating material are described. The first procedural steps are with both Film base materials the same.

First, an annular pattern 3 is applied to a copper foil M by a screen printing process Copper foil 4 is designed as a tape and can be provided with transport openings 11 on both sides Film supports themselves are then made of an insulating material Such transport holes are not absolutely necessary, as these can also be attached to the insulating film carrier 1. Applying the ring-shaped pattern to the copper foil is referred to as process step A in FIG. 1. In the case of the plastic mass of the ring applied by screen printing shaped pattern can be, for example, polyimide Act. The screen printing process makes it easy to choose the thickness of the plastic compound applied. In the next In process step (B), the ring-shaped pattern 3 is burned onto the copper foil 4. The two described

Process steps A and B are the same for both types of film carriers (electrically conductive and insulating).

In the case of an electrically conductive film carrier, ° 5 step E the etching out of the conductor structures. Included the conductor strips (5) are held on the connection side of the semiconductor chip by the ring-shaped pattern 3. That the other end of the conductor strip is held by the film carrier. After finishing the connection of the Semiconductor chips, for example through thermocompression. Since the other connection side of the conductor strip is still through If the film carrier is held, an electrical test of the connections and the semiconductor chip is not possible. After the conductor strips have been separated, for example by punching out - '' 5, the electrical connection is made on a Substrate.

If the film carrier 1 is formed by an insulating material, the one provided with the ring-shaped patterns 3 becomes Copper foil is glued to the film carrier 1 in such a way that the pattern 3 lies down in prepared openings 2 comes. The openings 2 have larger internal dimensions than the external dimensions of the pattern 3 Foil Μ on the film carrier 1 is shown in Fig. 1 as Ver driving step C designated. In process step D takes place the etching of the conductor structures and the finishing. The use of a film carrier 1 made of insulating material enables the testing of the semiconductor chip after connection of the same, since the connection side of the semiconductor chip is removed. turned side of the conductor strip is held by the film carrier 1.

If the connection points are arranged on the semiconductor chip in several parallel rows, the ring-shaped Form pattern 3 such that the conductor strips 5 to in the vicinity of the connection points 7 supported by the same (β. Fig. 2).

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3 shows a semi-conductor chip 9 mounted on a substrate 10, at the connection point 8 of which a conductor strip is provided • 10 is connected, the conductor strip 5 through the annular pattern 3 is held. The connection point 8 of the Semiconductor chip is designed as a hump and has a Height of about 25um. The thickness of the ring-shaped pattern 3 is approx. 15 µm, which allows the conductor strip through the pattern 3 is isolated from the semiconductor chip 9 and, on the other hand, a good contact is ensured, whereby the height of the connection point 8 can also be reduced by the thermocompression.

It is conceivable to use the insulating film base, which as a rule has a thickness of 100 to 125 µm, for forming of the annular pattern 3 to be used. However, this could have been a special etching process for the etching of the ring-shaped pattern from the film carrier result. With a further etching process, the thickness of the ring-shaped pattern would then have to be increased be reduced accordingly. Not to mention that Such a method is not possible at all in the case of an electrically conductive film carrier, is offered by the one according to the invention Process through the formation of an insulating ring-shaped pattern to support the conductor strips both in the case of film carriers made of electrically conductive as well as electrically insulating material fewer process steps for forming the annular pattern, the thickness of which can be determined in a simple manner.

P 3766 30. U. 1982 Fs / Me.

Claims (6)

Telefonbau und Normalzeit GmbH, Postfach M4 32, 6000 Frankfurt / Main Process for the production of a film carrier with conductor structures Patent claims: nj Process for the production of a film carrier with etched conductor structures for integrated circuits with connection points on the surface of the chip at which the finger-shaped im Connection area self-supporting conductor strips of the conductor structures can be connected, characterized by the following steps: 1. Application of a ring-shaped pattern (3) made of a Kusntstoffmasse in the Be to be supported rich of conductor structures by screen printing a copper foil (H). 2. Burning in the screen print. 3. Etching of the conductor structures (5). k. Refining. 2. The method according to claim 1, characterized by the following steps: 1. Applying a ring-shaped pattern (3) made of a plastic compound in the area of the conductor structures to be supported by screen printing on a copper foil ( k). ItIl l.l t «· Ι · 2. Burning in the screen print. 3 · Glue the copper foil (4) onto a insulating openings (2) having Film carrier (1) such that the pattern (3) down in the openings (2). 4. Etching out the conductor structures (5). 5. Refining. 3. The method according to any one of claims 1 or 2, characterized in that that polyimide is used as the plastic compound. 15th 4. The method according to any one of claims 1 to 3, characterized in that that the thickness of the pattern (3) is smaller than the height of the connection points (6) of the semiconductor chip, which are designed as bumps. 5. The method according to any one of claims 1 to k, characterized in that that the pattern (3) in the connection area of the semiconductor chip (9) of the conductor strips (10) of the conductor structure to extends to the connections (7). 6. The method according to any one of claims 1 to 5, characterized in that that with connection points (6) arranged in several parallel rows on the surface of the semiconductor chip (9) the conductor strips in the connection area (10) the conductor structures (5) up to the connections (7) are supported by the pattern (3). P 3766 30.H.1982 Fs / Me.