JPS6152977B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a semiconductor device.

The conventional general mass production method for semiconductor devices has used a punching frame made of a thin metal plate. However, since such frames are divided into about 14 consecutive frames at most, it has been impossible to supply frames continuously. In order to improve this drawback, a flexible film substrate 3 has been proposed, as shown in FIG. 1, in which a copper foil 2 is pasted on a heat-resistant plastic layer 1 made of polyimide, polyamideimide, or the like. However, the heat-resistant plastic layer 1 of this flexible film substrate 3 is extremely expensive, and is therefore unsuitable for mass production of semiconductor devices.

The present invention has been made in view of this point, and provides a method for manufacturing a semiconductor device that eliminates the conventional drawbacks. An embodiment of the present invention will be described in detail below with reference to FIGS. 2 to 8.

The first step of the present invention is to form a flexible film substrate 10, as shown in FIGS. 2 and 3. This film substrate 10 is made by bonding two copper foils 11 and 12 together with a thermosetting resin adhesive 1.
It is formed by crimping with step 3. These two copper foils 11,
Reference numeral 12 uses a copper foil with a thickness of approximately 35μ, which is used for printed circuit boards, etc., and after applying an adhesive 13 made of a thermosetting resin such as epoxy resin to one surface of one or both of the copper foils 11 and 12, the adhesive 13 is pressed with a roller. The two copper foils 11 and 12 are integrated into a film. As the thermosetting resin used here, for example, those described in Japanese Patent Publication No. 55-20394 may be used. In this way, the two pieces of copper foil are approximately 30 μm apart from each other.
It is electrically insulated with a thin adhesive 13 and has a dielectric strength of at least 600V and on average about 2500V.

The film substrate 10 is cut into strips having a predetermined width, for example, 50 mm, and is wound up into a cartridge in units of, for example, 50 m in length for manufacturing. As shown in FIG. 3, index holes 14 are punched out at regular intervals on both ends of the strip-shaped film substrate 10 where the desired conductive pattern is not provided, and the index holes 14 are used to assign positions in the subsequent manufacturing process. The film substrate 10 is unloaded and transferred.

As shown in FIG. 4, the second step of the present invention consists in etching the copper foil 11 on one side of the film substrate 10 to form a large number of desired conductive patterns 15 successively at regular intervals in the length direction. Conductive pattern 1
Reference numeral 5 denotes a fixing pad 16 and a fixing pad 1 provided approximately in the center of the film substrate 10 on which a semiconductor element is placed.
It is composed of a plurality of electrode leads 17 extending in four directions from the vicinity of 6. Also, this electrode lead 1
7 are arranged in parallel in each direction and at regular intervals, and ultimately function as external terminals.

Incidentally, in order to protect each conductive pattern 15 from the force applied when transferring the film substrate 10 during manufacturing, index holes 1 are provided at both ends of the film substrate 10.
A continuous strip pattern 18 including the conductive pattern 15 is provided, and if necessary, a connecting pattern 19 for connecting the strip patterns 18 in a ladder shape is provided to completely surround the conductive pattern 15. At this time, the conductive pattern 15 is made electrically independent from the strip pattern 18 and the connection pattern 19, and each electrode lead 17 is also made electrically independent from each other.

The third step of the present invention, as shown in FIG. 5, consists in etching the other copper foil 12 of the film substrate 10 to form support patterns 20 corresponding to each conductive pattern 15. The support pattern 20 is formed so as to overlap the fixing pad 16 of the conductive pattern 15 shown by the dotted line and the vicinity of the fixing pad 16 where the electrode lead 17 is bonded.
This support pattern 20 integrally supports the fixing pad 16 and the ends of all electrode leads 17 via the adhesive 13, and the conductive pattern 15 is used in place of the thin layer of adhesive 13 that has no supporting function. To support.

Further, in order to reinforce the band pattern 18 and the connection pattern 19 described above, a reinforcing pattern 21 is provided in a portion corresponding to the band pattern 18 and connection pattern 19, leaving the other copper foil 12. Furthermore, a back lead 22 is provided corresponding to the part of each electrode lead 17 that serves as an external terminal, leaving the other copper foil 12, and this back lead 22 is extended and connected to the reinforcing pattern 21, and the other part of each electrode lead 17 is connected to the reinforcing pattern 21. The ends are also integrally supported by the reinforcing pattern 21.

As described above, even if the conductive patterns 15 are electrically independent, the support patterns 20 provided on the back side,
Since the reinforcing pattern 21 and the back lead 22 can be integrally supported within the frame formed by the strip pattern 18 and the connecting pattern 19 via the adhesive 13, the film substrate 10 can be used for manufacturing.

Copper foil 11 in the second step and main step described above,
Twelve etchings can be performed simultaneously. That is, after screen printing a resist in a desired shape on the copper foils 11 and 12 on both sides of the film substrate 10, the film substrate 10 is continuously fed into a double-sided etching device, and an etching solution is sprayed onto both sides of the film substrate 10 from opposing nozzles. Perform etching on both sides at the same time.

Further, a nickel plating layer is deposited on necessary parts of the conductive pattern 15, for example, at least the ends of the electrode leads 17 on the fixing pad 16 side where ultrasonic bonding is performed.

As shown in FIG. 6, the fourth step of the present invention is to attach a semiconductor element 2 to the fixing pad 16 of each conductive pattern 15
3 is fixed, and the electrodes of the semiconductor element 23 and the corresponding electrode leads 17 are connected using bonding thin wires. The bonding thin wire is bonded onto the nickel plating layer described above.

Film substrate 1 on which conductive patterns 15 etc. are formed
Index hole 1 from the cartridge containing 0
4 to feed the film substrate 10 frame by frame, and after fixing the semiconductor elements 23 to the fixing pads 16 of each conductive pattern 15 using silver paste or solder, the film substrates 10 are bonded to correspond to the electrodes of the semiconductor elements 23 by an automatic bonding device. The electrode lead 17 is connected with a thin aluminum bonding wire. Since each electrode lead 17 is electrically independent, after bonding is completed, a test needle is placed on each electrode lead 17 and energized to test the circuit function of each semiconductor element 23. If necessary, perform function trimming, etc. If the semiconductor element 23 is defective, the semiconductor element 23 is replaced and regenerated, or a special mark is attached and the subsequent assembly process is stopped to improve the yield of the finished product.

After this inspection, the semiconductor element 23 and the bonding wire are coated with a protective resin such as silicone resin.

The fifth step of the present invention, as shown in FIG. 7, consists in molding the conductive pattern 15 of the film substrate 10 with a resin 24 except for the electrode lead 17 which will become the external terminal.

The resin mold is moved frame by frame with the film substrate 10 as it is, and powdered epoxy resin is sprayed on one or several pieces at a time and heated and hardened to expose the electrode leads 17 which will become external terminals, and the whole is molded. Thereafter, the electrode lead 17 and reinforcing pattern 21 are cut at the portion indicated by the dashed line in FIG. 7 to separate the semiconductor devices into individual semiconductor devices. Note that the electrode lead 17
Since the electrode lead 17 and the back lead 22 are insulated by the adhesive 13, a through hole 25 is provided as shown in FIG. 8, and the hole is filled with solder 26 to electrically connect the electrode lead 17 and the back lead 22. . Further, the back lead 22 is used when soldering to a printed circuit board.

As described in detail above, according to the present invention, it is possible to mass-produce an inexpensive film carrier method using a film substrate with two copper foils bonded together without using a polyimide film or the like. Further, according to the present invention, the circuit function test of the semiconductor element can be carried out while the semiconductor element remains in the film form after being fixed, and the yield of finished products is greatly improved.
Furthermore, according to the present invention, the film can be manufactured in a film state until the final step, and a consistent film carrier system can be established.

[Brief explanation of the drawing]

FIG. 1 is a sectional view illustrating a well-known flexible substrate, FIG. 2 is a sectional view illustrating a flexible film substrate to which the present invention is applied, and FIGS. 3 to 7 are plan views illustrating each process of the present invention. , FIG. 8 is a sectional view illustrating a semiconductor device completed according to the present invention. Explanation of main figure numbers, 10...Film substrate, 11,
12... Two copper foils, 15... Conductive pattern, 17...
Electrode lead, 20... Support pattern, 23... Semiconductor element, 24... Molding resin.

Claims (1)

[Claims] 1. A step of bonding two copper foils with a thermosetting resin and forming a film substrate insulated from each other with the resin, a fixing pad for a semiconductor element formed by etching one of the copper foils of the substrate, and the fixing. forming a conductive pattern consisting of a plurality of electrode leads extending from the vicinity of the pad; forming a support pattern formed by etching the other copper foil of the substrate and overlapping a portion of the fixing pad and the electrode lead; a step of fixing a semiconductor element to the fixing pad and connecting an electrode of the element to the electrode lead by bonding; and a step of exposing a portion of the electrode lead that will become an external terminal and molding the whole. A method for manufacturing a semiconductor device, characterized in that: