JPH0452997Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a semiconductor device equipped with a semiconductor element such as an IC chip, and particularly relates to a connection structure between a printed circuit board and a sealing frame disposed thereon. It is.

[Prior art]

FIG. 7 is a sectional view of a conventional plastic package type semiconductor device. As shown in the figure, an IC chip 52 is mounted on a predetermined position of a printed circuit board 51, and a conductive layer 53 patterned on the printed circuit board 51 and the IC chip 52 are connected by bonding wires 54, respectively. has been done. In order to protect the IC chip 52 and bonding wires 54, a sealing frame 55 with an open center is placed on the printed circuit board 51, and a synthetic resin 56 is injected into the hollow part of the frame and solidified.
IC chip 52 and each bonding wire 54
was buried in synthetic resin 56 and sealed.

In the figure, 57 is a cap, 58 is a lead pin, and 59 is an adhesive.

[Problem that the invention attempts to solve]

By the way, this conventional semiconductor device uses a liquid adhesive 59 to fix the sealing frame 55 on the printed circuit board 51. Therefore, a part of the adhesive 59 protrudes inward and covers the conductive layer 53, which becomes an obstacle to bonding the wire 54 later.
There are problems with connection reliability.

Furthermore, it takes time for the adhesive 59 to dry, which not only reduces work efficiency, but also causes the sealing frame 55 to shift from the top of the printed circuit board 51 before it dries, which may impair the appearance.

Conventionally, a molding frame for a printed circuit board as described in Japanese Utility Model Application Publication No. 62-36541 has been proposed.

This molding frame has a plurality of pins having locking claws at their tips integrally formed on the side facing the printed circuit board, and the pins are press-fitted into positioning holes provided in the printed circuit board. The structure is such that the mold frame is fixed onto the printed circuit board by engaging the locking pawl with the rear opening edge of the printed circuit board.

Although this proposal has improved workability compared to the conventional method in which the printed circuit board and the mold frame were bonded together using an adhesive, it has the following drawbacks.

Since the distance between the bottom surface of the molding frame and the locking pawl is constant, when the thickness of the printed circuit board becomes thinner, even if the molding frame is mounted on the printed circuit board, there will be no play between the two. occurs.
Therefore, the synthetic resin poured into the molding frame may flow out through the gap between the printed circuit board and the molding frame.

In order to prevent this from happening, whenever the thickness of the printed circuit board changes, the molding frame must be remolded and the distance between the bottom of the molding frame and the locking claw must be adjusted. must be changed according to the thickness of the printed circuit board.

Since the molding frame is placed on the top surface of the printed circuit board on which the conductive pattern is formed, the frame cannot be made of metal.
Generally, it is molded from synthetic resin that has electrical insulation properties.

On the other hand, glass-epoxy resin is commonly used as a material for printed circuit boards, but it is harder than the synthetic resins.

Therefore, the pin for the mold frame (made of synthetic resin)
When the pin is press-fitted into the positioning hole of the printed circuit board (glass-epoxy resin), the pin may break or the ridge of the locking claw formed at the tip of the pin may be scraped and worn out. The problem is that the locking effect of the locking pawl is reduced and it is easy to come off the printed circuit board.

An object of the present invention is to eliminate such drawbacks of the prior art and provide a semiconductor device with high reliability and good productivity.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention places a sealing frame on a printed circuit board on which a semiconductor element is mounted, and injects a resin into the opening of the sealing frame.
In a semiconductor device having a structure in which the semiconductor element is sealed by solidification, the sealing frame and the printed circuit board are provided with a first through hole and a second through hole, respectively, which communicate with each other when both are superposed. a first protrusion that is slightly larger in outer size than a first through hole provided in the sealing frame; and a first protrusion that is slightly larger in outer size than a second through hole provided in the printed circuit board. and two protrusions whose protrusion lengths from the pin peripheral surface are shorter than the protrusion length from the pin circumferential surface of the first protrusion, respectively, are provided on the lead pin, and the lead pin is attached to the first transparent portion of the sealing frame. By press-fitting from the hole side toward the second through hole side of the printed circuit board, the first protrusion bites into the inner peripheral part of the first through hole, and the second protrusion is inserted into the second through hole. This is characterized in that the sealing frame and the printed circuit board are integrally connected by the lead pins that bite into the inner peripheral portion.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a semiconductor device according to an embodiment, FIG. 2 is an enlarged side view of a lead pin used in the semiconductor device, and FIGS. 3 and 4 explain part of the assembly order of the semiconductor device. Sectional view for, 5th
This figure and FIG. 6 are a front view and a side view showing a modified example of the lead pin.

The printed circuit board 1 is made of, for example, glass-epoxy resin, and has a recessed portion approximately in the center thereof for mounting the IC chip 2 thereon. Further, on the upper surface, a conductive layer 3 is patterned into a predetermined shape. The IC chip 2 and the conductive layer 3 are electrically connected by a bonding wire 5.

A sealing frame 4 made of glass-epoxy resin is placed and fixed on the printed circuit board 1 in the same way, and the hollow part of the sealing frame 4 is filled with, for example, epoxy resin, silicone resin, or ultraviolet curing resin. A synthetic resin 6 made of, for example, is injected and solidified, and the aforementioned IC chip 2 and bonding wire 5 are buried airtightly. Furthermore, a flat cap 7 is attached and fixed onto the sealing frame 4.

Fixing of the sealing frame 4 to the printed circuit board 1 is as follows:
This is done using a large number of lead pins 8. Next, this fixing method will be explained.

As shown in FIG. 2, a first annular protrusion 9 is formed on the head of the lead pin 8, and a second annular protrusion 10 is formed slightly on the lower end side of the first annular protrusion 9. On the other hand, as shown in FIG. 3, the sealing frame 4 has a first through hole 11, and the printed circuit board 1 has a first through hole 11 so as to communicate with each other when the sealing frame 4 and the printed circuit board 1 are overlapped. A second through hole 12 is formed in each. Note that the outer diameter D1 of the first annular protrusion 9, the outer diameter D2 of the second annular protrusion 10, the inner diameter D3 of the first through hole 11, the inner diameter D4 of the second through hole 12, and the outer diameter D2 of the second annular protrusion 10, The pin diameter D5 is designed to have a relationship of D1>D3>D2>D4≧D5.

As shown in FIG. 3, first, the printed circuit board 1 and the sealing frame 4 are placed one on top of the other so that the centers of the first through hole 11 and the second through hole 12 are aligned. Next, each lead pin 8 is inserted from the first through hole 11 with the first annular protrusion 9 facing upward.

When inserted in this way, as shown in FIG. 4, the portion of the lead pin 8 below the second annular protrusion 10 is inserted into the second through hole 12 of the printed circuit board 1, and the second annular protrusion 10 is sealed. First through hole 1 of retaining frame body 4
1, and the first annular protrusion 9 protrudes upward from the sealing frame 4, and the lead pin 8 is held in an upright position.

Next, these are placed on a base 14 having a large-diameter escape hole 13 at a position facing the second through hole 12, and each lead pin 8 is driven into the printed circuit board 1 side in one stroke using a press 15. As a result, the first annular protrusion 9 firmly bites into the inner peripheral part of the first through hole 11 provided in the sealing frame 4, while the second annular protrusion 10
firmly bites into the inner circumference of the second through hole 12. By press-fitting the lead pin 8 in this manner, the sealing frame 4 and the printed circuit board 1 can be integrally connected via the lead pin 8.

The steps after connecting in this manner are the same as those of the conventional art, so their explanation will be omitted.

5 and 6 are views showing modified examples of the lead pin 8. In this example, a part of the lead pin 8 is mechanically crushed to form a substantially flat protrusion 1.
6 is formed. This protrusion 16 corresponds to the second annular protrusion 10 of the embodiment described above, and its outer dimension L is designed to satisfy the relationship D3>L>D4.

Alternatively, the head of the lead pin may be crushed to form a substantially flat protrusion, in short, the first
Since it is sufficient to form the protrusion and the second protrusion, the shapes of these protrusions can be changed as appropriate.

As mentioned above, since the sealing frame and the printed circuit board are integrally connected by the lead pins, multiple rows of lead pins are provided to constitute the lead pin rows,
If these lead pin rows are arranged to face each other with the semiconductor element in between, that is, the lead pin rows can be arranged on the left and right with the semiconductor element in between, or the lead pin rows can be arranged so as to surround the semiconductor element so that the lead pin rows are square when viewed from the top. By arranging them in this shape, the connection force between the sealing frame and the printed circuit board becomes stable and strong.

Furthermore, as described in the above embodiment, if the sealing frame and the printed circuit board are made of the same material, their linear expansion coefficients are the same, so even if thermal changes occur, the sealing frame and the printed circuit board There is no possibility of distortion occurring between the substrate and the substrate. In the embodiment, the printed circuit board and the sealing frame are made of the same material, but they may be made of different materials as long as they have substantially the same coefficient of linear expansion. Further, when used under conditions with little thermal change, the printed circuit board and the sealing frame may be made of any material.

In the above embodiment, a glass-epoxy resin composite material was used as the material of the printed circuit board, but the material is not limited to this, and any material may be used.

In the above embodiment, a recess is provided in the printed circuit board,
Although the semiconductor element is placed inside it, it is not limited to this, for example, it can be directly bonded onto the conductive layer, and the present invention can be applied to single-sided boards, double-sided boards, multilayer boards, etc. can.

Further, in the above embodiments, an embodiment using a cap has been described, but the present invention can also be applied to an embodiment that does not use a cap.

[Effect of idea]

The present invention has the above-mentioned structure, and since no adhesive is used unlike conventional methods, there is no possibility of poor connection between the conductive layer and the wire bonding due to adhesive extrusion, resulting in improved reliability. I can figure it out. Further, since the sealing frame and the printed circuit board can be integrated in an extremely short time, work efficiency is greatly improved. Furthermore, since the structure is such that the first protrusion bites into the inner periphery of the first through hole, and the second protrusion bites into the inner periphery of the second through hole, the thickness of the printed circuit board changes somewhat. However, since the biting position of the protrusion only changes, unlike the previously proposed method, there is no possibility that play will occur between the printed circuit board and the mold frame, and the synthetic resin for the mold will flow out from there. In addition, the distance between the bottom of the mold frame and the locking pawl may need to be changed in response to changes in the thickness of the printed circuit board, or the pin may break or the locking pawl may become worn out, causing the locking effect to deteriorate. The disadvantage of being lost is eliminated.

Furthermore, the length of the second protrusion from the pin circumferential surface is made shorter than the protrusion length of the first protrusion from the pin circumferential surface, and the lead pin is placed on the first through-hole side of the sealing frame. Since the second protrusion is press-fitted toward the second through-hole side of the printed circuit board, when the second protrusion passes through the first through-hole of the sealing frame, the hole becomes larger and the inner periphery of the first through-hole becomes larger. The first protrusion does not bite into the surface weakly, and the first protrusion and the sealing frame are firmly connected.

Because of this, it is possible to provide a semiconductor device with good productivity.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a semiconductor device according to an embodiment of the present invention, FIG. 2 is an enlarged side view of a lead pin used in the semiconductor device, and FIGS. 3 and 4 are part of the assembly sequence of the semiconductor device. 5 and 6 are front and side views showing modified examples of lead pins, and FIG. 7 is a sectional view of a conventional semiconductor device. 1...Printed circuit board, 2...IC chip, 3...
...Conductive layer, 4... Sealing frame, 5... Bonding wire, 6... Synthetic resin, 7... Cap, 8...
Lead pin, 9...first annular protrusion, 10...second
Annular protrusion, 11...first through hole, 12...second through hole, 16...protrusion.

Claims (1)

[Claims for Utility Model Registration] (1) A sealing frame is placed on a printed circuit board on which a semiconductor element is mounted, and a resin is injected into the opening of the sealing frame and solidified. In a semiconductor device having a structure for sealing, the sealing frame and the printed circuit board are each formed with a first through hole and a second through hole that communicate with each other when both are superposed, and the sealing frame is sealed. a first protrusion having an outer dimension slightly larger than the first through hole provided in the printed circuit board, and a first protrusion having an outer dimension slightly larger than the second through hole provided in the printed circuit board and a protruding length from the pin circumferential surface. Sasa said first
A second protrusion shorter than the protrusion length from the pin peripheral surface is provided on each lead pin, and the lead pin is moved from the first through-hole side of the sealing frame to the second through-hole side of the printed circuit board. By press-fitting the lead pin toward A semiconductor device characterized in that a sealing frame and a printed circuit board are integrally connected. (2) Utility Model Registration Claim 1: The semiconductor device according to claim (1), wherein the first protrusion and the second protrusion are annular protrusions. (3) Utility model registration Claim (1), characterized in that the lead pins are provided in a plurality of rows to form a lead pin row, and the lead pin rows face each other with the semiconductor element in between. semiconductor devices. (4) The semiconductor device according to claim (1) of the utility model registration, characterized in that the sealing frame and the printed circuit board are made of the same material.