JPH0756820B2 - Semiconductor device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device in which a large number of lead pins are mounted on a chip on board, and more specifically, a plating treatment is performed on the inner surface of a through hole into which the lead pins are mounted. The present invention relates to a semiconductor device in which a through hole is formed by forming a through hole, and a locking portion which engages with the inner circumference of the through hole and caulks and fixes the lead pin is provided below the top of the lead pin.

(Prior Art and Problems Thereof) A semiconductor device described in Japanese Utility Model Publication No. 50-62054 is conventionally known as a semiconductor device in which a large number of lead pins are attached to a chip on board.

This semiconductor device is a so-called non-through hole type in which a circuit is formed on the surface of a substrate made of a ceramic material, and a lead pin is inserted into a through hole which is connected to the circuit and which is located near the top of the lead pin. Form a flat and thin locking part (convex part) with an almost inverted triangle shape, press the locking part into the through hole and crimp the lead pin, then connect the top part of the lead pin and the circuit with conductive paint It is supposed to do.

In the conventional semiconductor device having such a configuration,
Since the substrate is a ceramic material, a complicated process is required to form the circuit, and a post process to apply the conductive paint to the connection between the lead pin and the circuit is required, which makes the work troublesome and increases the manufacturing cost. There were drawbacks such as.

(Problems to be Solved by the Invention) In order to solve the above conventional drawbacks, the substrate is formed of an organic material (resin material), and the inner surface of the through hole opened in the substrate is used as a circuit on the substrate surface. It is conceivable that the through-hole portion is formed by connecting and plating, and the locking portion is press-fitted into the through-hole portion to caulk and fix the lead pin.

When such a configuration is adopted, there is an advantage that the circuit can be easily formed on the surface of the substrate and the lead pin and the circuit are connected only by inserting the lead pin into the through hole portion, but the side of the locking portion There is a possibility that the corner portion existing at the edge portion may damage the plated layer in the through-hole portion and cause conduction failure.

In order to solve the above-mentioned problems, the locking portion provided on the lead pin has a shape in which a side edge portion thereof does not have a corner portion (for example, Japanese Utility Model Publication No.
It is also conceivable to have a substantially semicircular shape as shown in No. 59-98998). However, in this case, since the protrusion width of the locking portion needs to be larger than that of the conventional one in order to securely fix the lead pin by caulking, it is possible to completely achieve the prevention of damage to the through hole portion when the locking portion is press-fitted. Was a difficult thing to say.

It is also possible to prevent the damage by plating the inner surface of the through hole with Ni or the like, but it is only necessary to form the surface layer made of Ni plating or the like to prevent the heat shock due to the operation of the semiconductor device. The surface layer is apt to crack and is not suitable for use.

The present invention has been made in view of such conventional circumstances, and an object of the present invention is to facilitate the formation of a circuit on the surface of a substrate by using a substrate made of an organic material, and to open the substrate. The through hole inner surface is plated to form a through hole portion, and the lead pin is provided with a locking portion that engages with the inner circumference of the through hole portion so that the lead pin and the circuit can be connected simply by inserting the lead pin. In the semiconductor device, the inner surface (plating layer) of the through hole portion is prevented from being damaged when the locking portion is inserted into the through hole portion, the semiconductor device can be manufactured at low cost without requiring complicated steps, and is highly reliable. To provide.

(Means for Achieving the Object) In order to achieve the above object, in the semiconductor device of the present invention, a large number of through holes are formed in a chip-on-board made of an organic material, and each through hole is inserted from the lower end side. A lead pin comprising a leg rod portion, a crown portion formed at an upper end of the leg rod portion and engaging with an edge of a through hole portion, and a flat thin-walled locking portion formed below the crown portion are inserted and attached. The through hole portion is formed by laminating a thick plating protective layer made of Ni plating on the surface of a circuit layer made of Cu plating, and the locking portion of the lead pin has a protrusion width slightly larger than the inner diameter of the through hole portion and the leg rod. With a thickness smaller than the part diameter, and the side edge surface portion that comes into pressure contact with the inner periphery of the through hole portion has a flat thin shape with a gentle arc shape, the locking portion is press-fit into the through hole portion, and the side edge surface portion Allowed pressure direction vertices site through hole inner surface exits, characterized in that riveted lead pins with.

In addition, for the reason described below, it is useful to stack a metal plating having good wettability with solder on the surface of the Ni plating layer in the through hole portion and to perform Sn plating on the surface of the lead pin.

(Operation) According to the above configuration, the chip on board (that is, the substrate)
Since it is formed of an organic material, it is possible to easily form a circuit on the board and open a prepared hole for a through hole. Further, since the lead pin is provided with the flat and thin locking portion, the lead pin and the circuit can be connected only by inserting (press-fitting) the lead pin into the through hole portion.

In addition, the side edge surface of the locking portion is formed into a gentle arc shape that is less likely to damage the inner circumference of the through hole portion, and at the same time,
The protective layer made of Ni plating protects the circuit layer made of Cu plating and improves slippage when the lead pin is press-fitted, and almost completely prevents damage to the through hole when press-fitting the locking portion.

In addition, by forming the protective layer made of the Ni plating as a thick plated layer, the occurrence of cracks in the protective layer due to the heat shock associated with the operation of the semiconductor device is minimized, and the caulking fixing force applied to the locking portion is reduced. Make sure to improve the lead pin firmly.

Furthermore, when a metal plating with good wettability with solder is laminated on the surface of the Ni plating layer and Sn plating is applied to the lead pin surface, slippage at the time of press-fitting the lead pin is improved and the through hole portion is fixed after fixing the lead pin. Solder adhesion at the time of soldering the periphery and making the fixation more reliable is improved.

(Example) Hereinafter, one example of the present invention will be described with reference to the drawings.

In the figure, (A) is a chip-on-board formed with an organic material such as plastic or glass epoxy resin to a thickness of 1 mm, and (B) is forcedly pressed into the through-hole portion (1) of the chip-on-board (A). It is a lead pin

A circuit (not shown) is formed on the surface of the chip on board (A) by a usual method. Also, at appropriate points on the chip-on-board (A), through holes are drilled through the pilot holes (1a) with a circular planar shape and a hole diameter of 0.6 mm, and the circuits are connected to the inner surface of each pilot hole (1a). Cu plating (1b) 12 to 13μ to form the circuit layer, and Ni plating (1c) 12 to
13μ is applied to form a thick plating protective layer, and the surface of the metal plating has good wettability with solder, namely Au plating (1
d) 1 μ is applied to form the through hole portion (1).

The lead pin (B) is made of an alloy of iron and nickel and is Sn-plated (5) on the surface. The lead pin (B) has a smaller diameter than the inner diameter of the through hole (1) above the upper end of the rod (2). A disk-shaped crown (3) having a diameter larger than the inner diameter of (1) is integrally formed.

The leg rod (2) is mounted on the chip-on-board (A) when the lead pin (B) is attached to the through hole (1).
The length should be appropriate to project downward. Also, the leg rod (2)
Below the parietal region (3), the through hole (1)
Flat and thin circular protrusion-shaped engaging part that engages with the inner circumference (4)
Is formed.

The locking part (4) has a projection width (x) slightly larger than the inner diameter of the through hole part (1) and a thickness (y) smaller than the diameter of the leg rod part (2).
And is formed into a flat thin-walled shape having a gentle arc shape on the side edge surface portion (4a) pressed against the inner periphery of the through hole portion (1), and the side edge surface portion is press-fitted into the through hole portion (1). The apex portion (4b) of the protruding direction (4a) is pressed against the inner surface of the through hole portion (1), whereby the lead pin (B) inserted into the through hole portion (1) is firmly caulked and fixed.

To give more specific dimensions of the locking portion (4), the protrusion width (x) is about 0.65 to 0.75 mm, and the thickness (y) is 0.18 to 0.22 mm.
Within the range, the optimum value is 0.7m for the protrusion width (x).
m, thickness (y) is 0.2 mm.

Then, if the lead pin (B) is inserted into the through hole portion (1) from the lower end side and the locking portion (4) is forcibly pressed into the through hole portion (1), the lead pin (B) is removed. While firmly crimping and fixing in the through-hole portion (1), connect to the circuit on the surface of the board (A).

Further, at this time, the side edge surface portion (4a) of the locking portion (4) has a gentle arc shape, and at the same time, the protective layer made of Ni plating (1c) protects the Cu plating (1b) layer and the locking portion. (4) Sliding at the time of press fitting can be improved, and damage to the through hole portion (1) at the time of press fitting of the locking portion (4) can be almost completely prevented. Also, Ni
Since the protective layer composed of the plating (1c) is a thick plated layer of about 12 to 13 μ, the generation of cracks in the protective layer due to the heat shock accompanying the operation of the semiconductor device is minimized, and the locking portion ( 4) The caulking fixing force applied to 4) is further improved to more securely fix the lead pin (B).

Furthermore, since the Au plating (1d) having good wettability with solder is laminated on the Ni plating (1c) surface and the Sn plating (5) is applied to the lead pin (B) surface, the locking portion (4) is press-fitted. In addition to the improvement of the slippage at the time, the solder adhesion at the time of soldering around the through hole portion (1) after fixing the lead pin (B) is improved.

The soldering is performed by supporting the lead pin (B) fixed by crimping by the locking portion (4) and the lead pin (B).
And the through hole portion (1) for more reliable electrical connection with the circuit. After the lead pin (B) is caulked and fixed, the lower surface side of the board (A) is dipped in a solder solution to form the through hole portion (1). Capillary phenomenon that occurs in the gap (6) between the inner surface and the lead pin (B) causes the solder liquid to rise to cover the crown (3) and fill the gap (6).
Make sure that the lead pin (B) is firmly fixed.

(Effect of the Invention) As described above, in the semiconductor device of the present invention, since the chip-on-board (that is, the substrate) is made of an organic material, it is easy to form a circuit on the board and to open a prepared hole for a through hole. You can do it. Further, since the through hole portion is formed on the substrate and the flat and thin locking portion is provided on the lead pin, the lead pin and the circuit can be connected only by inserting (press-fitting) the lead pin into the through hole portion.

In addition, the side edge surface of the locking part has a gentle arc shape, and at the same time, the Ni plating layer protects the circuit layer made of Cu plating to improve the sliding when the lead pin is press-fitted and press-fit the locking part. Prevents damage to the through hole part almost completely.

Further, by forming the protective layer made of Ni plating as a thick plated layer, the generation of cracks in the protective layer due to the heat shock accompanying the operation of the semiconductor device is minimized, and the caulking fixing force applied to the locking portion is minimized. To improve the reliability of lead pin fixation.

Therefore, it is possible to provide a highly reliable semiconductor device which can be manufactured by a simple operation and low cost without requiring a complicated process and in which the connection of the circuit of the lead pin is extremely surely performed.

Further, if the outermost surface layer of the through-hole portion is plated with a metal having good wettability with solder and the lead pin surface is plated with Sn, it is possible to further improve the slippage at the time of press-fitting the lead pin and further enhance the above-mentioned effect. In addition, there are many effects such as improving the solder adhesiveness when soldering around the through hole portion after fixing the lead pin.

[Brief description of drawings]

The drawings show an embodiment of a semiconductor device according to the present invention.
The figure is a cross-sectional view of the through hole where the lead pin is caulked and fixed, Fig. 2 is a side cross-sectional view of Fig. 1, and Fig. 3 is II of Fig. 1.
It is a sectional view taken along the line I-III. In the figure, (A) …… chip on board, (B) …… lead pin, (1) …… through hole, (1b) …… Cu plating, (1c) …… Ni plating, (1d) …… Au plating, (2)
…… Legs, (3) …… Parietal, (4) …… Locking part,
(4a) …… side edge surface part, (4b) …… apex part, (5) ……
Sn plating, (6) ... shows gaps, respectively.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Kubokawa 8-5-1 Shimorenjaku, Mitaka City, Tokyo Inside the Mitaka Factory of Tanaka Electronic Industry Co., Ltd. (56) References Showa 50-62054 (JP, U) Showa Showa 51-103649 (JP, U) Actually opened Showa 53-37076 (JP, U)

Claims (2)

[Claims] 1. A chip-on-board made of an organic material is formed with a large number of through-holes, and each of the through-holes has a leg rod portion to be inserted from the lower end side and a through-hole portion edge formed at the upper end of the leg rod portion. A lead pin consisting of a crown portion to be engaged and a flat and thin locking portion formed below the crown portion is inserted and attached, and the through hole portion is formed on the surface of the circuit layer made of Cu plating with Ni.
It is formed by stacking a thick plating protective layer made of plating, and the locking portion of the lead pin has a protrusion width slightly larger than the inner diameter of the through hole portion and a thickness smaller than the diameter of the leg rod portion, and is pressed against the inner circumference of the through hole portion. The side edge surface part to be formed has a flattened thin shape with a gentle arc shape, and the locking part is press-fitted into the through hole part, and the apex part of the protruding direction of the side edge surface part is pressed against the inner surface of the through hole part to caulk and fix the lead pin. A semiconductor device characterized by: 2. The method according to claim 1, wherein a metal plating having good wettability with solder is laminated on the surface of the Ni plating layer in the through hole portion, and Sn plating is applied to the surface of the lead pin. The semiconductor device described.