JPS6342878B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an electronic circuit device, including an IC,
This relates to an electronic circuit device in which electronic components such as LSI chips, chip resistors, and chip capacitors are mounted on a board formed of a resin film and a metal frame.After the metal frame is held by magnets or vacuum suction, By sealing electronic components with resin, the substrate is flattened and fine wiring can be easily formed.

A conventional example of a high-density electronic circuit package will be described with reference to FIG. First, a resin film 2 having a thermoplastic adhesive layer 3 is fixed to a metal frame 1 made of nickel or the like. Next, a through hole 4 is formed in the resin film 2 at a portion corresponding to an electrode 5' of an electronic component such as a chip capacitor 5 to be fixed later. Next, the chip capacitor 5 is fixed to the adhesive layer 3 by aligning the through hole 4 with the electrode 5' of the chip capacitor 5. At this time, since the resin film 2 is fixed by thermocompression bonding, the resin film 2 is stretched, and the chip capacitor 5
protrudes from the metal frame 1. Next, the chip capacitor 5 is sealed with a resin 11 such as epoxy resin or silicone resin. Finally, after removing the adhesive layer 3 on the electrode 5' of the chip capacitor 5 by dry etching etc., the adhesive layer 3 is removed on the resin film 2.
A metal film of Cr/Cu, Al, etc. is formed, and conductive wiring 6 is formed by photoetching.

In this conventional example, since electronic components such as chip capacitors are sealed with resin while protruding from the metal frame, there are the following drawbacks.

(1) When resist is spin-coated during the fet-etch process when forming conductor wiring, the resist will not stick to the protruding parts.

(2) Due to the reason in (1), it is necessary to increase the thickness of the resist film, which reduces the resolution and makes it difficult to form fine wiring, making it impossible to achieve high density.

(3) When performing close exposure, the resist pattern becomes thicker due to the gap 7 in Figure 1, so the conductor wiring 8
and 9 are not separated by etching and are electrically short-circuited by the conductor layer 10 caused by the etching residue.

The present invention was made in view of such problems,
An embodiment of the present invention will be described with reference to FIG.

First of all, as shown in Figure 2a, nickel,
A resin film 22 having a thermoplastic adhesive layer 23 is fixed to a metal frame 21 made of Kovar, stainless steel, or the like. The thickness of the metal frame 21 is usually about 100 to 200 μm. In this embodiment, the adhesive layer 23 is FEP,
The case where the resin film 22 is made of polyimide will be described. Usually the thickness of each is 2.5~2.5 for FEP23
12.5μ, and polyimide 22 has a thickness of about 7.5 to 25μ.
Also, the melting point of FEP is around 290℃, so 280℃
By heating to about 340° C. and applying pressure, a strong adhesion to the metal frame 21 is obtained.

Next, as shown in FIG. 2b, using a photoresist as a mask, through holes 2 are formed in the polyimide 22 by chemical etching or dry etching.
form 4. When chemical etching is performed here, a NaOH solution is used. In the case of dry etching, O ₂ gas, N ₂ gas, etc. are used. The size of the through hole 24 is usually 60 to 100 μ□
That's about it.

Next, as shown in FIG. 2c, the electrode 25' of the chip capacitor 25 and the through hole 24 are aligned,
Chip capacitor 25 with FEP23 as adhesive,
It is fixed to the polyimide film 22. At this time too,
As in the case of fixing the metal frame 21, strong fixation can be obtained by heating to 280° C. to 340° C. and applying pressure.
At this time, due to the fact that it is fixed by thermocompression bonding and the polyimide film 22 is very thin,
The polyimide film 22 stretches, and the chip capacitor 25 protrudes from the metal frame 21.

Next, as shown in FIG. 2d, the metal frame 21 is held by the magnet 32 with the polyimide film 22 interposed therebetween. At this time, the metal frame 21 is made of a magnetic material such as nickel. Furthermore, since the polyimide film 22 is very thin, the polyimide film 22 has almost no effect on the force with which the magnet 32 holds the metal frame 21 .

After that, epoxy resin or silicone resin 3
1 or the like, the chip capacitor 25 is sealed with resin. Here, the metal frame 21 is held by a magnet 32, and since the resin film 22 is very thin and flexible, the metal frame 21 and the chip capacitor 25 have flat surfaces. That is, it is possible to obtain a flat state in which the surface of the film 22 does not protrude from the surface to which the film 22 and the frame are fixed.

In addition, if the metal frame 21 is not a magnetic material, as shown in FIG. By holding the suction table 33, the metal frame 21 and the chip capacitor 25 are
The surface can be made almost completely flat. Furthermore, instead of using a magnet or vacuum suction, mechanical pressure may be used to obtain a flat state.

Finally, the FEP on the electrode 25' of the chip capacitor 25 is removed by dry etching using O ₂ gas or N ₂ gas. Thereafter, by a method such as vapor deposition or plating on the polyimide film 22,
A metal film such as Cr/Cu, Ni, etc. is formed, and conductor wirings 26, 2 are formed by photoetching as shown in Fig. 2f.
Form 8, 29. Conductor wiring 26, 28, 29
When a two-layer film of Cr/Cu is used, the respective thicknesses are usually about 0.1μ for Cr and 3μ for Cu. Also,
Etching is performed for Cr by chemical etching using hydrochloric acid or dry etching using carbon tetrachloride, etc., and for Cu by chemical etching using a ferric chloride solution, cupric chloride solution, etc.

Further, in this embodiment, the conductor wiring is formed after the electronic component is sealed with resin, but the electronic component may be sealed with resin after the conductor wiring is formed. Electronic components include ICs and LSIs other than chip capacitors.
Of course, it may also be a chip, a resistor, etc.

As described above, in the present invention, since the electronic component such as a chip capacitor and the surface of the metal frame are made substantially flat, the electronic component is sealed with resin, so that the following effects can be obtained.

(1) Since the resin film surface is flat, a very uniform film thickness can be obtained during the resist application process when forming conductor wiring, and there are no areas where resist does not stick as in the conventional method, making the film extremely thin. can do.

(2) Due to the reason in (1), the resolution of the resist is greatly improved, so fine conductor wiring can be formed and high density can be easily achieved.

(3) In the case of contact exposure, the gap that was a problem in the past does not occur, so the resist pattern can be formed faithfully to the mask pattern, and the conductor wirings 38 and 39 shown in FIG. No short circuit defects occur.

As described above, according to the present invention, it is possible to accurately and accurately perform high-density mounting.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional electronic component mounting body;
Figures a to f are manufacturing process diagrams of an electronic circuit package according to an embodiment of the present invention. 21...Metal frame body, 22...Resin film, 2
3... Adhesive layer, 24... Through hole, 25... Chip capacitor, 25'... Chip capacitor electrode,
26, 28, 29... Conductor wiring, 31... Sealing resin, 32... Magnet, 33... Vacuum adsorption stand.

Claims (1)

[Claims] 1. A step of fixing a resin film to a thin metal frame, a step of forming micropores in the resin film, and a step of fixing an electronic component to the surface of the resin film to which the metal frame is fixed. step, and the surface of the resin film to which the metal frame is fixed, with the opposite side of the resin film to which the metal frame is fixed, with no part protruding from the resin film surface on the metal frame; forming a resin layer to cover the electronic component; forming a conductor wiring on the opposite side of the resin film to which the metal frame is fixed; and connecting the conductor wiring and the electronic component through the micro holes; A method of manufacturing an electronic circuit device, comprising the step of electrically connecting the electrode and the metal frame. 2. Claim 1, characterized in that the opposite side of the resin film to which the metal frame is fixed has no part protruding from the surface of the resin film on the metal frame using a magnet. A method for manufacturing an electronic circuit device according to. 3. Claim 1, characterized in that the opposite side of the resin film to which the metal frame is fixed has no part protruding from the surface of the resin film on the metal frame by vacuum suction. A method for manufacturing an electronic circuit device according to paragraph 1. 4. Claims characterized in that the opposite side of the resin film to which the metal frame is fixed has no part protruding from the surface of the resin film on the metal frame by mechanical pressure. A method for manufacturing an electronic circuit device according to item 1.