JPS6286745A - Semiconductor device - Google Patents

Abstract

PURPOSE:To improve workability by a method wherein a semiconductor chip, wiring pattern, and other circuit elements are sealed with glass cloth semi- hardened by impregnation of resin and a planar molding. CONSTITUTION:A prepreg frame 11 is built of glass cloth heated and dried after being applied or impregnated with a solution in which an epoxy resin (molecular weight approximately 300-2,000), a hardening agent (dicyandiamide, etc.), and a catalytic substance (3rd-grade amine, imidazoles, etc.) are diluted in a solvent (dimethyformamide, methyl ethyl ketone, methyl cellosolve, etc.). A polymer layer is formed on one side of a planar metal plate 12. The prepreg frame 11 constitutes the side walls of a capping section and is bonded to a substrate 1 and to the polymer-coated metal plate 12. Elimination of the steric processing of a molding and of surfaces whereto the molding is to be bonded facilitates the manufacturing work, eliminates the need of an adhesive agent, reduces the space required, and accomplish miniaturization.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to semiconductor devices, and particularly to thinning of devices.

The present invention relates to a sealing structure for a semiconductor device that facilitates miniaturization and improves dimensional stability, productivity, and yield.

[Conventional technology]

In general, circuit boards on which semiconductor chips and the like are mounted and wiring patterns formed are potted with synthetic resin or sealed with molded materials to prevent the intervention of moisture and impurities and to provide moisture resistance and iNj impact resistance. will be held. However, potting made of synthetic resin has a problem in that the composition and thickness of the resin are non-uniform and warpage occurs due to heating and curing shrinkage of the sealing resin. For this reason,
Recently, a method of sealing by covering the cap with a molded product of metal, ceramic, or plastic has been attracting attention.

FIG. 3 shows an example of a conventional camp-type sealing structure. In the figure, ■ is the board, 2 is the wiring pattern,
3 is a conductive plate, 4 is a conductive paste, 5 is a semiconductor chip,
6 is a bonding wire, 7 is a cap portion, and 8 is an adhesive.

(Problems to be solved by the invention) Since the conventional semiconductor device is configured as described above,
The gear/7 part 7 should be carefully designed to avoid contact with the semiconductor chip 5, bonding wire 6, wiring pattern 2, etc. by considering the height and width of the cap, and to ensure good adhesion to the board. It was necessary to consider and design the surface, and then mold it using molding methods such as pressing and injection molding. As a result, the number of steps increases, the cost goes up, and productivity suffers. In addition, the adhesive 8 generally uses a liquid resin such as epoxy, but when it is heated and cured, the viscosity of the resin decreases and the resin enters the sealing interior, causing wire bonding, semiconductor chips, etc. The hardening shrinkage causes stress, which causes wire bonding to break, semiconductor chips to crack, and other failures. In addition, there have been other problems such as the adhesive dripping out and causing the adhesive to protrude to the outside, resulting in an uneven dimension, and the height of the cap becoming uneven depending on the amount of adhesive.

Further, when sealing a module such as an IC card, it is necessary to take measures as shown in FIG. 4, for example, in order to make the thickness of the camp-forming moldings uniform. In Figure 4, 1 to 7 are the same as in Figure 3, 9 is resin, 10 is
is a frame. In the sealing method as shown in FIG. 4, the number of steps is increased and the dimensions of the IC module are increased by the frame, which is a big problem when miniaturization is required as much as possible.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a semiconductor device that can improve workability and yield and can be easily miniaturized.

[Means for solving problems]

In the semiconductor device according to the present invention, a glass cloth is impregnated with a resin and semi-cured, and this is arranged to surround a circuit element on a circuit board to form a side wall, and a flat plate covering the circuit element is placed on the side wall. The side wall is completely cured by heating, and the side wall, the circuit board, and the plate-like molded product are bonded to each other.

(Function) In this invention, since the circuit elements on the circuit board are sealed with semi-cured glass cloth impregnated with resin and a flat molded product, the molded product can be easily produced and By semi-curing the resin having an adhesive function to a desired state, sealing can be performed with less resin dripping.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a cross-sectional view of a sealing structure for a semiconductor device according to an embodiment of the present invention. In the figure, 1 to 6 are the same as in FIG. 3, and 1) is a glass cloth impregnated with resin. This is a prepreg frame that is semi-cured to reduce resin dripping, protects semiconductor chips, and bonds substrates and metal plates. This is, for example, a commercially available epoxy resin (molecular weight approximately 3
00 to 2000), a curing agent (e.g. dicyandiamide), and a known catalyst (tertiary amine, imidazole, etc.), diluted with a solvent (e.g. dimethylformamide, methyl ethyl ketone, methyl cellosolve, etc.), and then put it on a glass cloth. It is coated or impregnated and then heated and dried.

In addition, 12 is a metal plate formed into a flat plate shape, which protects the semiconductor chip from external stress and prevents moisture from entering.
Reference numeral 13 denotes a single polymer layer formed on the metal plate 12 to prevent contact between the metal plate 12 and bonding wires or wiring patterns.

Next, the effects will be explained. In one embodiment,
The prepreg frame 1) becomes the side surface of the cap part of the conventional tank structure, and the substrate 1 and the polymer-coated metal plate 12
It has the function of adhering to. This eliminates the need for three-dimensional processing of the molded product and its adhesive surface, which facilitates processing, eliminates the need for adhesive, saves space, and allows for miniaturization. Also, the above prepreg frame 1
) can be prevented from reaching the desired semi-cured state, and dimensional accuracy can be improved. Furthermore, by appropriately selecting the curing agent and catalyst for the resin, desired low-temperature and short-time curing can be performed, thereby further improving workability. Moreover, since the prepreg frame has insulating properties, there is no problem of discharge even if it comes into contact with the wiring pattern, and the yield can be increased.

FIG. 2 shows another embodiment of the present invention, in which numerals 1 to 13 are the same as in FIG. 1, and in this embodiment, a semiconductor chip 5 is embedded in a semiconductor substrate 1. Even in such a configuration, the same effects as in the above embodiment can be obtained.

In both of the above examples, the prepreg frame was semi-cured by coating or impregnating glass cloth with a commercially available epoxy resin, curing agent, and catalyst appropriately diluted with a solvent. Any material may be used as long as it has excellent heat resistance, moisture resistance, etc.

Regarding adhesive strength, by adding a high molecular weight composition such as phenoxy resin to the prepreg resin composition, a non-crosslinkable linear component is interposed in the crosslinked network, making it possible to impart flexibility to the resin. It is also possible to increase the adhesive strength.

Furthermore, in both of the above examples, metal was used as the flat plate-shaped molded product, but it may be made of ceramic, plastic, etc., which is thin but strong, has excellent heat resistance and moisture resistance, is resistant to rust, and is magnetic. Stainless steel (SUS304
) is more preferable.

In addition, in both of the above embodiments, there was a hollow space between the substrate and the metal plate, but this part was filled with a gel-like resin that could alleviate stress from the outside and give less stress to the outside. May be enclosed.

〔Effect of the invention〕

As described above, according to the present invention, semiconductor chips, wiring patterns, and other circuit elements are sealed with semi-cured glass cloth impregnated with resin and a flat molded product. In addition to protecting bonding wires, improving moisture resistance, and impact resistance, it also eliminates the molding process of cap-type molded products, makes the device thickness uniform, downsizes IC modules, and prevents failures due to adhesive dripping. Prevention, dimensions can be done.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a semiconductor device according to an embodiment of the present invention, FIG. 2 is a sectional view showing another embodiment of the device, and FIGS. 3 and 4 are sectional views each showing an example of a conventional device. It is. In the figure, 1 is a substrate, 2 is a wiring pattern, 3 is a conductive plate, 4 is a conductive paste, 5 is a semiconductor chip, 6 is a bonding wire, 1) is a prepreg frame, 12 is a metal plate, 1
3 is a single layer of polymer. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A side wall is formed to surround the circuit element on a circuit board on which a circuit element is mounted using semi-cured glass cloth impregnated with a resin, and a flat plate-like material is formed on the side wall to cover the circuit element. 1. A semiconductor device comprising: placing a molded product; heating the side wall to completely cure the side wall; and adhering the side wall to the circuit board and the flat molded product.