JPS62204581A - Window cap - Google Patents

Abstract

PURPOSE:To prevent the stress to be generated in the flanges of a metal frame at the time of resistance-welding from being transmitted to the low-melting point glass and the light- transmitting plate by a method wherein the upper wall with a penetrated hole formed therein is continuously provided on the upper ends of the sidewalls of the metal frame, the penetrated hole is used as the light-transmitting plate sealed with the low-melting point glass and parts of the sidewalls at the sites being separated from each other are each formed to have a wall thickness thinner than that of the sidewalls at other sites. CONSTITUTION:A light-transmitting plate 6 is sealed on an upper wall 4 of a metal frame 1 with a low-melting point glass 7 and covers a penetrated hole 5. The wall thickness of he whole region of each sidewall 2 is formed in a thin-walled thickness of nearly 1/2 of the wall thickness of the upper wall 4. Parts of the sidewalls 2 at other sites are each formed in a wall thickness of 70% or thereabouts of that of the upper wall 4 because the sidewalls are stretched at the time of draw processing. There is no possibility that the stress to occur along with the deformation to be generated in flanges 3 of the metal frame 1 when a stem is resistance welded to this window cap is transmitted to the low-melting point glass 7 and the light-transmitting plate 6 because the stress comes to be absorbed in these sidewalls 2 in such a way as to make the thin-walled sidewalls 2 deform. Accordingly, the generation of crack in the low-melting point glass 7 and the light-transmitting plate 6 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention mainly relates to a window cap used in a semiconductor device.

[Prior art and its problems]

In semiconductor laser devices, solid-state imaging devices, and the like, the elements are generally hermetically sealed with a window cap made of a metal frame with a light transmitting plate provided in the light path.

The metal frame 1 of such a window cap generally includes:
As shown in FIG. 3, a cylindrical or square I-shaped side wall 2 is provided with seven flange 3 around the outer circumference of the lower end, and an upper wall with a through hole 5 formed at the upper end of the side wall 2. 4 are arranged in series.

Then, the window cap is constructed by covering the through hole 5 with a light transmitting plate such as a glass plate (not shown).

By the way, when such a window cap or a stem on which a semiconductor element or the like is mounted is resistance welded, the flange 3 is slightly deformed. Then, the stress caused by this deformation is transmitted through the side wall 2 to the low melting point glass and the light transmitting plate that join the light transmitting plate to the metal frame 1, and cracks occur in the low melting point glass and the light transmitting plate. Ta.

[Purpose of the invention]

In view of these points, it is an object of the present invention to provide a window cap in which stress generated in the flange during resistance welding between the window cap and the stem is not transmitted to the low melting point glass or the light transmitting plate. do.

[Summary of the Invention] The present invention provides a method in which a flange is fixed to the outer periphery of the lower end of the side wall of a metal frame, an upper wall in which a through hole is formed is connected to the upper end of the side wall, and the through hole is sealed with low melting glass. The window cap covered with a light transmitting plate is characterized in that at least a part of the side wall of the portion spaced apart from the low melting point glass is formed to be thinner than the circled portion over the entire circumferential direction.

[Actual IM example of invention]

The present invention will be explained below with reference to embodiments shown in the drawings. Note that structures similar to those of the conventional structure described above are designated by the same reference numerals in the drawings, and their explanations will be omitted.

FIG. 1 shows a first embodiment of the present invention. In this embodiment, a light transmitting plate 6 such as a glass plate is sealed to the upper surface 4a of the upper wall 4 of the metal frame 1 with a low melting point glass 7. and covers the through hole 5. In this embodiment, the thickness of the entire side wall 2 of the metal frame 1 is particularly thin, approximately half the thickness of the upper wall 4. In order to form such a metal frame 1, the shape of the punch used when drawing the metal frame 1 with a press should be taken into consideration.

Moreover, instead of forming the entire area of the side wall 2 of the metal frame 1 to be approximately 1/2 thinner than the thickness of the upper wall 4, only approximately 1/2 of the height of the side wall 2 is circumferentially formed. It may be formed to be approximately 1/2 thin over the entire area in the direction. Note that the side wall 2 in other parts is stretched during the drawing process, so the thickness is approximately 70% of the thickness of the upper wall 4.

According to the above-described structure, the stress caused by the deformation of the seven flange 3 of the metal frame 1 when the stem (not shown) is resistance welded to the window cap is absorbed by the thin side wall 2 by deforming it. Therefore, there is no risk that this stress will be transmitted to the low melting point glass 7 or the light transmitting plate 6, and therefore the occurrence of cracks in the low melting point glass 7 or the light transmitting plate 6 is prevented.

According to an experiment regarding the crack occurrence rate of the light transmitting plate 6 in this embodiment and the conventional one, it was found that cracks occurred in 80% of the light transmitting plate 6 in the conventional one, but cracks occurred in the entire area of the side wall 2 or In the window cap of this example in which approximately 1/2 of the range in the height direction was made thin, the reduction was 0%, and a remarkable effect was observed.

FIG. 2 shows a second embodiment of the present invention. In this embodiment, the light transmitting plate 6 has a low melting point on the thin part 2a of the side wall 2 of the metal frame 1 and the lower surface 4b of the upper wall 4. It is sealed with a glass 7 and covers the through hole 5.

In this embodiment, a metal frame 1 with a total height of about 7M is used.
The lower part of the side wall 2 is formed to be approximately 1/2 thinner than the thickness of the upper wall 4 over its entire circumferential area, with the upper end located 1.5 m below the lower surface 6a of the light transmitting plate 6.

The upper end of this thin portion 2a is located below the lower end of the low melting point glass 7 joined to the inner surface 2b of the side wall 2.

According to the above-described configuration, the stress caused by the deformation of the flange 3 when resistance welding is performed to the stem (not shown) on the window cap is absorbed by the thin wall portion 2a of the side wall 2, so that the stress is absorbed by the thin wall portion 2a of the side wall 2. There is no risk of cracks occurring.

'According to an experiment on the crack occurrence rate of the light transmitting plate 6 in this embodiment and the conventional one, it was found that 80% of the cracks occurred in the light transmitting plate 6 in the conventional one, but in this embodiment, cracks occurred in 80% of the light transmitting plate 6. 0% on window caps
A remarkable effect was observed. In addition, the crack occurrence rate was 30% when the whole area of the side wall 2 in the vertical direction was made thin so that the side wall at the joint part of the low melting point glass 7 was made thin.

〔Effect of the invention〕

As explained above, in the window cap according to the present invention, the thin wall portion of the side wall absorbs the stress caused by the deformation that occurs in the flange during resistance welding of the stem. There is no risk of cracks occurring in the board, and it has excellent airtightness with high reliability.

[Brief explanation of drawings]

FIGS. 1 and 2 are longitudinal sectional views showing an embodiment of a window cap according to the present invention, and FIG. 3 is a longitudinal sectional view showing a conventional metal frame. 1... Metal frame, 2... Side wall, 3... Flange, 4
...Top wall, 5...Through hole, 6...Light transmission plate, 7...
・Low melting point glass. Figure 1 Figure 2
Figure 3

Claims (1)

[Claims] 1) A flange is fixed to the outer periphery of the lower end of the side wall of the metal frame, and an upper wall in which a through hole is formed is connected to the upper end of the side wall, and the through hole is sealed with low melting point glass. A window cap covered with a light-transmitting plate, characterized in that at least a part of the side wall of a portion away from the low melting point glass is formed thinner than other portions over the entire circumferential area. . 2) The thickness of the thin portion of the side wall is approximately 1/2 of the thickness of the top wall.
Window cap as described in section.