JPH08111467A - Metal package for semiconductor - Google Patents

Abstract

PURPOSE: To achieve an airtight joint by forming a part extending to an exposed part and abutting against the side wall of a box type metal case and jointing between the outer face at a fitting part and the inner wall of an elongated hole and between the extending part and the side wall face of the box type metal case. CONSTITUTION: In order to secure a ceramic terminal 42 in an elongated hole 34, the ceramic terminal 42 is held by a jig such that the fitting part 42a thereof enters into a predetermined spatial position in the elongated hole 34. Silver-alloy brazing material is placed between the inner wall of the elongated hole 34 and a mutualization 48 and between an extending part 42c and the side wall 32a and then they are brazed in a furnace. The silver-alloy brazing material is fused to joint between the inner wall of the elongated hole 34 and a metallization 48 and between an extending part 42c and the side wall 32a airtightly through brazing. Although a gap is present the inner wall face of the elongated hole 34 and the outer wall face at the fitting part 42a, the silver-alloy brazing material is held in the gap by the surface tension to form meniscus thus keeping the airtightness well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal package for semiconductors, and more particularly to a box type metal package suitable for accommodating ultra-high speed semiconductor devices such as optical elements.

[0002]

2. Description of the Related Art Among semiconductor packages for accommodating ultra-high speed semiconductor devices such as optical elements, there is a box type metal case in which ceramic terminals each having a terminal portion formed on a ceramic base are attached. FIG. 6 shows an example of the above conventional semiconductor package, which is a box-type metal case 1.
A notch 14 opening to the upper end surface is formed in the side wall 12 of 0 by cutting, a separately formed ceramic terminal 16 is fitted into the notch 14, and the metallization 22 formed on the outer wall surface of the ceramic terminal 16 and the inside of the notch 14 A brazing material such as silver brazing is used to hermetically join the wall surface. When the notch 14 is deeper than the thickness of the ceramic terminal 16, a metal seal frame 18 is further prepared and brazed with a brazing material such as silver brazing.

FIG. 7 shows another conventional example. In the case of this conventional semiconductor package, the long groove 20 extending to both side walls adjacent to the side wall 12 of the box-type metal case 10 is provided.
Is formed by milling or the like, the separately formed ceramic terminal 16 is fitted into the long groove 20, and the metallization 22 formed on the outer wall surface of the ceramic terminal 16 and the inner wall surface of the long groove 20 are hermetically sealed with a brazing material such as silver solder. I try to join.

[0004]

However, the conventional metal package for a semiconductor described above has the following problems. That is, in the former case, since the thickness (width direction) of the ceramic terminal 16 is as thin as about 2 mm, the variation in dimension in the width direction is relatively small, but the contraction after firing is large in the length direction. Since the dimensional accuracy will vary, the cutout 14
In order to fit it in, it is ground and adjusted to the required size, and there is a problem that the number of steps is large and the cost is high. In the latter case, since the long groove extends over the entire length of the side wall, the ceramic terminals can be formed longer and the number of terminals can be increased, but on the contrary, the longer ceramic terminals tend to cause cracks. There is a problem.

Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to provide a metal package for a semiconductor, which is easy to manufacture and can reduce the cost.

[0006]

The present invention has the following constitution in order to achieve the above object. That is, in a metal package for a semiconductor in which a long hole is formed in a side wall of a box-type metal case for housing a semiconductor device, and a ceramic terminal is fixed to the long hole, the ceramic terminal has a terminal portion formed on a ceramic base. The ceramic base is formed at a fitting portion that fits into the elongated hole and an exposed portion that is exposed from the elongated hole. The ceramic substrate extends outward in the longitudinal direction at the exposed portion and contacts the side wall of the box-shaped metal case. An installation portion is formed, and the outer surface of the fitting portion and the inner wall surface of the elongated hole are joined together, and the extension portion and the side wall surface of the box-shaped metal case are joined together.

Further, in a metal package for a semiconductor in which a notch opening to a side wall end face is formed in a side wall of a box-type metal case for accommodating a semiconductor device, and the ceramic terminal is fixed to the notch, the ceramic terminal is A terminal portion is formed on the ceramic base body, and the ceramic base body is formed at a fitting portion that fits into the cutout portion and an exposed portion that is exposed from the cutout portion to the outside of the box-shaped metal case. An extension portion that extends outwardly in the direction of contact with the side wall of the box-shaped metal case is formed, and between the outer surface of the fitting portion and the inner wall surface of the cutout portion, and the extension portion and the side wall surface of the box-shaped metal case. The feature is that it is joined between. The long hole,
The cost can be reduced by forming the notch by pressing or etching.

[0008]

The operation will be described with reference to FIG. The inner wall surface of the long hole 34 and the outer wall surface of the fitting portion 42a, and the extended portion 42c and the side wall 32a are airtightly joined by silver brazing. Although there is a gap between the inner wall surface of the long hole 34 and the outer wall surface of the fitting portion 42a, the silver solder is held in the gap by the surface tension, a meniscus is formed, and the airtightness is kept good. An extension portion 42c is formed at the longitudinal end portion of the ceramic terminal 42, and the extension portion 42c abuts the surface of the side wall 32a and airtightly joins them with a brazing material, so that the length of the fitting portion 42a is increased. The precision of is not so required, and it is only necessary to be able to enter the long hole, so that the polishing process is not required unlike the conventional case. Further, the cost can be reduced by forming the long holes 34 by pressing. Further, when the long holes 34 are formed by etching, it is not necessary to manufacture a die for pressing, and thus a small number of products of various types can be manufactured at low cost.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows an example of the box-type metal case 30. Reference numeral 32 denotes a frame body, and in this embodiment, it is formed into a rectangular frame shape by bending one band-shaped member and joining the end faces. Side walls 32a of the frame 32, 3
Of the side walls 32a, 32c of 2b, 32c, 32d,
Long holes 34 for fixing the ceramic terminals are formed respectively. The long holes 34 are formed by pressing before forming the frame 32, that is, at the stage of the band-shaped member. The long holes 34 may be formed by etching. Reference numeral 36 denotes a bottom plate, which is formed of a metal having excellent heat dissipation such as copper-tungsten and covers one opening side of the frame 32 and is fixed to the frame 32 by a brazing material such as silver brazing. Reference numeral 38 is a hole for inserting a fixing screw.

FIG. 2 shows another embodiment of the box type metal case 30. In this embodiment, the box-shaped metal case is expanded, the metal plate is pressed into a shape in which the frame body 32 and the bottom plate 36 are connected, and then bent at a bent portion provided with a groove (not shown) inside to join the joint portion. To form the box-shaped metal case 30 by brazing. The long holes 34 are previously formed in the side walls 32a and 32b by pressing. If the amount is small, the metal plate may be processed and the long holes may be formed by etching. Reference numeral 40 is a notch formed in the bottom plate 36 for inserting a fixing pin (not shown).

FIG. 3 is an explanatory view showing a fixing structure of the ceramic terminal 42. As described above, by forming the long hole 34 by pressing, the manufacturing cost can be significantly reduced as compared with the cutting or milling. The long hole 34
However, it is difficult to form the corner portion at a right angle due to the clearance between the punch and die of the press machine, and some radius is generated as shown in the figure.

Reference numeral 42 is a ceramic terminal. The portion 42a is a fitting portion formed to have a size (width, depth, length) that can enter the long hole 34. As described above, the rounded portion has a rounded corner portion, but the fitting portion 42a may have such a size that it can easily enter the long hole 34 even if the corner portion has a rounded portion. Therefore, a gap may be formed between the inner wall surface of the long hole 34 and the outer wall surface of the fitting portion 42a. As described above, since it is not necessary to adjust the size of the long hole 34 and the fitting portion 42a as in the conventional case, the polishing process after firing the ceramic terminal 42 is unnecessary.

Reference numeral 42b is an exposed portion which is exposed outside the elongated hole 34. The longitudinal end portion of the exposed portion 42b is formed as an extended portion 42c extending outward from the end portion of the fitting portion 42a. The extending portion 42c has a long hole 34 in the fitting portion 42a.
Has a length sufficient to abut the side wall 32a in the longitudinal direction of the elongated hole 34 when it is inserted into. Fitting part 42a and extension part 4
As shown in FIG. 4, the corner portion with 2c is formed into a radius having an appropriate curvature. By forming the corner portion into a round shape in this way, it is possible to prevent the occurrence of cracks. The fitting portion 42a and the exposed portion 42b form a ceramic base.

A step portion 43, which is lower than the upper end surface and is open to the front surface side, is formed at the exposed portion 42b, and an external terminal 44 is formed on the step portion 43. Further, a step portion 45 that opens to the rear surface side is also formed in the fitting portion 42a, and the step portion 4 is formed.
Internal terminals 46 are formed on the upper surface 5. The external terminal 44 is for external connection, and the internal terminal 46 is electrically connected to a semiconductor device (not shown) mounted on the bottom plate 36 of the box-type metal case 30. Of course, the internal and external terminals 4
4 and 46 are also conducting.

The outer periphery of the fitting portion 42a, the rear surface side of the extending portion 42c, a part of the upper and lower surfaces of the exposed portion 42b adjacent to the fitting portion 42a, and the corner portions of the fitting portion 42a and the extending portion 42c. Metallization for brazing 48
(Hatched portion) is formed. The ceramic terminals 42 are formed by stacking green sheets formed into a required shape and firing them. The metallization 48 is formed by applying a metal powder paste in advance at the stage of the green sheets and simultaneously firing the green sheets. You can This point, FIG.
Since the conventional one shown in (1) needs to be polished, it is fired, and after polishing, a metal powder paste is applied and re-fired to form a metallization.

To fix the above-mentioned ceramic terminal 42 in the elongated hole 34, the ceramic terminal 4 is fixed by a jig (not shown).
The second fitting portion 42a is held so as to enter a predetermined space position in the long hole 34, and the inner wall of the long hole 34 and the metallization 48 are held.
, And between the extended portion 42c and the side wall 32a, silver brazing is interposed to braze in the furnace. As a result, the silver brazing material is melted, and the inner wall surface of the elongated hole 34 and the outer wall surface of the fitting portion 42a and the extended portion 42c and the side wall 32a are hermetically joined by the silver brazing material. Inner wall surface of long hole 34 and fitting portion 4
Although there is a gap between the outer wall surface of 2a, the silver solder is held in the gap due to surface tension, a meniscus is formed, and the airtightness is kept good. After mounting the semiconductor device, the opening of the frame 32 is sealed with a cap (not shown).

FIG. 5 shows another embodiment. In this embodiment,
The side wall 32a, 32c of the box-type metal case 30 is formed with a cutout portion 50 that opens to the end surface. In the same manner as described above, the cutout portion 50 can be easily formed by pressing when forming the box-shaped metal case 30. The ceramic terminal 42 is the same as that shown in FIG.

Also in this embodiment, when the ceramic terminal 42 is fixed to the notch 50, it can be carried out in substantially the same manner as the embodiment shown in FIG. That is, the fitting portion 42a of the ceramic terminal 42 is held by a jig (not shown) so as to enter a predetermined space position in the cutout portion 50, and the space between the inner wall of the cutout portion 50 and the metallization 48 and the extended portion are held. Brazing is performed in the furnace with silver solder interposed between 42c and the side wall 32a. As a result, the silver solder melts and the inner wall surface of the notch 50 and the fitting portion 4
The outer wall surface 2a and the extended portion 42c and the side wall 32a are airtightly joined by silver brazing. Although there is a gap between the inner wall surface of the cutout portion 50 and the outer wall surface of the fitting portion 42a, the silver solder is held in the gap by the surface tension, and a meniscus is formed to maintain good airtightness.

The upper end side opening of the notch 50 is provided with a semiconductor device (not shown) and then a cap (not shown).
Sealed. In addition, the cutout portion 50 has a ceramic terminal 42.
If it is deeper than the width, the seal frame can be brazed as in the conventional case shown in FIG. Further, in the above-mentioned embodiment, the notch 50 is formed by pressing in terms of cost, but it goes without saying that it may be formed by cutting instead of pressing. In this case, the frame body can be formed by cutting a square pipe, and the bottom plate can be brazed to the frame body to form a box-type metal case (not shown).

Although the present invention has been variously described with reference to the preferred embodiments, the present invention is not limited to these embodiments, and many modifications can be made without departing from the spirit of the invention. Of course.

[0021]

As described above, according to the metal package for a semiconductor of the present invention, an extending portion is formed at the longitudinal end portion of the ceramic terminal, and the extending portion abuts the side wall surface. Since the gap is airtightly joined with a brazing filler metal, the precision of the length of the fitting part is not so much necessary, and it is only necessary to be able to enter into the long hole or notch, so no polishing is required as in the past, and cost is reduced. Can be reduced. Further, the cost can be further reduced by forming the long hole or the notch by pressing or etching.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a box-type metal case.

FIG. 2 is a development view showing a second embodiment of the box-type metal case.

FIG. 3 is an explanatory view showing a state in which a ceramic terminal is fixed to an elongated hole.

FIG. 4 is an explanatory diagram of a ceramic terminal.

FIG. 5 is an explanatory diagram showing another embodiment.

FIG. 6 is an explanatory diagram showing a conventional ceramic terminal fixing method.

FIG. 7 is an explanatory view showing another conventional fixing method of the ceramic terminal.

[Explanation of symbols]

 30 box-type metal case 32 frame 32a, 32b, 32c, 32d side wall 34 long hole 36 bottom plate 42 ceramic terminal 42a fitting part 42b exposed part 42c extended part 43 step part 44 external terminal 45 step part 46 internal terminal 48 metallized 50 notch Department

Claims (3)

[Claims] 1. A metal package for a semiconductor in which a long hole is formed in a side wall of a box-type metal case for housing a semiconductor device, and a ceramic terminal is fixed to the long hole, wherein the ceramic terminal has a ceramic base and a terminal portion. The ceramic base is formed in a fitting portion that fits into the elongated hole and an exposed portion that is exposed from the elongated hole, and extends outwardly in the longitudinal direction at the exposed portion to form a side wall of the box-shaped metal case. An extended portion that abuts is formed, and the outer surface of the fitting portion and the inner wall surface of the elongated hole are joined together, and the extended portion and the side wall surface of the box-shaped metal case are joined together. Metal package for semiconductors. 2. A metal package for a semiconductor, wherein a notch opening to a side wall end face is formed on a side wall of a box-type metal case for accommodating a semiconductor device, and a ceramic terminal is fixed to the notch, wherein the ceramic terminal is A terminal portion is formed on the ceramic base body, and the ceramic base body is formed at a fitting portion that fits into the cutout portion and an exposed portion that is exposed from the cutout portion to the outside of the box-shaped metal case. An extension portion that extends outwardly in the direction of contact with the side wall of the box-shaped metal case is formed, and between the outer surface of the fitting portion and the inner wall surface of the cutout portion, and the extension portion and the side wall surface of the box-shaped metal case. A metal package for a semiconductor, characterized in that it is joined to the metal package. 3. The metal package for a semiconductor according to claim 1, wherein the elongated hole and the notch are formed by pressing or etching.