JPS5811113B2 - electronic circuit equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thin electronic circuit device in which a large number of electronic components are mounted in high density.

So-called hybrid IC technology has traditionally been used to package electronic components at high density.
This technology requires high costs because the substrate is made of ceramic material, and LSIs require connections using wire bonding, and especially complex circuits require multilayer wiring, but the costs in this case are extremely high. .

On the other hand, as a method that does not use wire bonding, which has poor workability, the substrate is made of a resin film such as polyimide,
The minimod method, which connects LSI electrodes to beam leads, has also been put into practical use.

However, the mini-Motsudo method has drawbacks such as the inability to form a wiring layer in the area where the beam leads are formed, which limits the ability to increase density, and the need for a fairly thick polyimide film for strength, resulting in high cost. .

The applicant has already filed a patent application for a method suitable for interconnecting a large number of devices with high density using a very thin film.
It was proposed in several specifications including No. 0-92773.

For example, in the above-mentioned Japanese Patent Application No. 50-92773, necessary through-holes are provided in an insulating resin film, and the element is adhered from the entire surface side of the insulating resin film so that the electrodes and the through-holes coincide with each other. A device is described in which a wiring layer is provided on the main surface side of the device, and at the same time, the electrodes of the device and the wiring are connected using the through holes.

The characteristic manufacturing method of this device is disclosed in Japanese Patent Application No. 51-30159.
Furthermore, a device having multiple wiring layers is described in Japanese Patent Application No. 7478/1983.

In all of the devices proposed here, the film substrate is extremely thin, 100% to 100% thinner than the conventional one, so a device that takes into consideration handling when fitting it into another package is proposed in Japanese Patent Application No. 52-25603.
This is the device described in the specification, in which a support such as a frame for reinforcement is provided on a film substrate.

Based on the above research results, the present invention uses a part of the metal support that reinforces the film substrate as wiring, and has sufficient strength while using a very thin film substrate. This is an electronic circuit device in which multilayer wiring is easily formed and electronic components are mounted at high density.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a completed electronic circuit device, and FIG. 2 shows a support made of metal or the like.

1 is an insulating resin film such as a polyamide film; 2 is a metal support provided on one side of the insulating resin film 1; 3 is a metal support provided on one side of the insulating resin film 1;
゜4.5 is an electronic component, which is mounted from the back side of the insulating resin film 1 in Fig. 1, and 3 is a semiconductor element such as an LSI;
4 is a chip resistor, and 5 is a chip capacitor.

6 is a wiring pattern formed on the surface side of the insulating resin film 1, and the wiring pattern 6, a part of the support 2, the electrodes of the semiconductor element 3, etc. are connected through the through holes γ provided at key points of the insulating resin film 1. has been done.

Note that Figure 3 is an enlarged perspective view of the main part of Figure 1, and Figure 4
The figure is a sectional view taken along line V-V in FIG. 3.

The manufacturing procedure of this device will be explained in more detail with reference to these drawings.

The insulating resin film is preferably made of a material that is heat resistant and flexible, and has a thickness of 10 μm or more, which is about 1/10 to 1/2 the thickness of conventional films.
A 50μ polyimide film is suitable.

An adhesive layer 8 made of FBP resin, epoxy resin, etc. is provided on one side of this insulating resin film 1, and approximately 1500 ml of adhesive layer 8 made of nickel stainless steel, Kovar, etc. is formed as shown in FIG.
A μ-thick support 2 is bonded by thermocompression at about 300°C.

At this time, since the expansion coefficient of the insulating resin film 1 is lower than that of the support 2, the insulating resin film contracts when the temperature returns to room temperature after bonding, and a so-called "flexible" surface is obtained.

This is extremely important for subsequent production.

Next, tapered through holes 7 are formed in the insulating resin film 1 and the adhesive layer 8 by selectively chemical etching and plasma etching at important points.

Then, the semiconductor element 3, chip resistor 4, etc. are bonded by thermocompression from the adhesive layer 8 side.

At this time, since the insulating resin film 1 serving as the substrate is transparent, alignment of the through holes 7 and the electrodes, etc. of the semiconductor element 3 is very easy, and workability is improved.

Note that the thickness of the support 2 can be approximately 50μ to 250μ, and it goes without saying that the greater the thickness, the better the strength. When electronic components such as No. 3 are placed on the same adhesive layer 8 side, it is desirable for the thickness of the support body 2 to be less than or equal to the thickness of the electronic components in terms of work.

Furthermore, Cr and Cu may be continuously vapor-deposited over the entire surface of the insulating resin film 1 without the support 2, etc., and may be subjected to plating treatment as the case may be.

At this time, the electrodes of the semiconductor element 3, the terminals of the chip resistor 4, a part of the support 2, and the vapor deposition layer are connected through the through hole 7 provided above.

Next, a wiring pattern 6 is formed by photoetching.

Here, a vapor deposition method was used to connect the front and back sides of the insulating resin film 1 via the through holes 7, but solder, conductive paste, electroless plating, etc. may also be used.

As is clear from the above, during the formation of the vapor deposited layer that will become the wiring pattern 6, not only electrodes etc. but also a part of the support 2 that will become the wiring.
It is also possible to easily obtain a multilayer wiring structure.

Note that in this embodiment, the electrodes of the semiconductor element 3 such as LSI do not require a special shape such as a bump-like electrode, and the semiconductor element 3 can be used as is, and the size of the through hole 7 is also 50 μm.
A square is sufficient, making it possible to significantly reduce the area required for the electrodes and their connections compared to the past.

If the support 2 above is formed into a shape with the outermost periphery as a frame as shown in Figure 2, it will maintain its strength even if it is a little thin and will be easier to handle in the above manufacturing process. Become.

Then, at the end of the process, if you cut the frame at an appropriate place, the first
The device shown in the figure is obtained.

As is clear from FIG. 1, a part of the support 2 protrudes outward from the insulating resin film 1 and is connected to the wiring pattern 6, so it can be used as a lead-out terminal of this device and is extremely useful. It's convenient.

Note that moisture resistance will be sufficient if a coating film such as silicone rubber is formed on the electronic component side.

In the above embodiment, the support body 2 not only serves as a reinforcing frame during manufacturing, but also uses a part of it as wiring, so multilayer wiring, which is essential especially when there are a large number of semiconductor elements 3, is possible and easy. High-density packaging can be achieved.

Moreover, when forming the vapor deposition layer on one side of the insulating resin film 1, the multilayer wiring structure is also possible because mutual connections are made simultaneously through the through holes 7, which eliminates the need to change the mask many times and deposit the vapor deposition layer. It can be formed extremely easily and accurately without repeating etching or etching.

Since the support 2 is adhered to one side of the insulating resin film 1 in a complicated shape even after being separated from the frame, it has sufficient strength even in the device shown in FIG. It won't crack or tear.

It is also very practical that a part of the support body 2 serves as a lead-out terminal of this device.

In the above embodiment, the case where the support 2 was formed only on one side of the insulating resin film 1 was described, but it is also possible to provide the support 2 on both sides as follows.

Adhesive layers such as FEP resin are provided on both sides of the insulating resin film 1.

A support 2 made of nickel or the like as shown in FIG. 2 is adhered to the back surface.

On the other hand, a thin copper foil is pressure-bonded to the entire surface, and an upper surface support is formed by etching.

Next, plasma etching is performed to remove the adhesive layer on the upper surface side of the portion where the upper surface support is not present.

The steps after forming the through hole 7 are the same as those in the above embodiment.

This latter embodiment has the following effects more than the embodiment shown in FIG.

In the latter case, the upper surface support is used for particularly long wiring or wiring near the lead terminal near the outer periphery of the device.

Since the electrical components on the back side of the film are connected to each other through a through hole and a wiring pattern formed by vapor deposition, this wiring pattern is used for fine mutual wiring near the electronic components.

As a result, in the embodiment shown in FIG. 1, vapor deposition and photoetching were performed over the entire surface of the film at once, which sometimes caused defects such as short circuits in the wiring pattern, but in the latter embodiment, the photoetching was carried out separately for each part. It is also possible to perform etching to produce fine wiring patterns, resulting in higher-density devices.

That is, the embodiment shown in FIG. 1 has the feature that higher-density packaging is possible in mass production than in the past, and the latter embodiment has the feature that it is possible to obtain a device with even higher density packaging.

As described above, the present invention includes a metal support selectively installed on at least one surface of an insulating resin film substrate and reinforcing the substrate, and a metal support on the main surface of the substrate so as not to overlap with the support. It consists of a fixed electronic component such as an LSI and a wiring layer selectively formed on the other main surface of the substrate, and the terminal of the electronic component and the wiring layer are connected to the through hole provided in the substrate. At the same time, a terminal or a wiring layer of the electronic component is connected to a part of the support, and the support is part of the electrical wiring, and a very thin substrate is used to reduce costs. On the other hand, it guarantees sufficient strength and can easily form a flat multilayer wiring structure.
An object of the present invention is to provide an electronic circuit device in which electronic components can be mounted with high density.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the electronic circuit device of the present invention, FIG. 2 is a perspective view of a support used in the above embodiment, FIG. 3 is an enlarged perspective view of a main part cut away, and FIG. FIG. 3 is a sectional view taken along line V-V in FIG. DESCRIPTION OF SYMBOLS 1...Insulating resin film, 2...Support, 3...Semiconductor element, 6...Wiring pattern, 7...Through hole .

Claims (1)

[Claims] 1 A metal support for reinforcing the insulating resin film substrate selectively placed on at least one whole surface of the substrate, and a metal support such as an LSI fixed to the main surface of the substrate so as not to overlap with the support. It consists of an electronic component and a wiring layer selectively formed on the other main surface of the substrate, and the terminal of the electronic component and the wiring layer are connected through a through hole provided in the substrate. . An electronic circuit device, wherein a terminal or a wiring layer of the electronic component is connected to a part of the support, and the support forms a part of the electrical wiring.