JPS6228781Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a glass-sealed case, and more particularly to a glass-sealed case in which a lead frame for automatic bonding is fixed.

Conventionally, lead frames such as those shown in FIGS. 1a and 1b have often been fixed to glass-sealed cases designed for automatic bonding. This type of lead frame has a small piece 4 combined with the inner lead tip 3, and has a structure designed to prevent the inner lead tip 3 from deforming during punching and lead frame fixing processes. It is becoming. The small piece 4 is kept in contact with the lead without falling out during cutting, and is pushed back to the original plate by the spring force in the lower mold at the same time as the upper mold of the press rises after cutting. Therefore, the inner lead tip 3 and the small piece 4 are structured so that they are held together and do not come off. Hereinafter, this type of lead frame will be referred to as a pushback type lead frame.

FIG. 2 shows a glass-sealed case with a conventional structure using a push-back lead frame. In the conventional structure, a ceramic substrate 8 is coated with a low melting point glass 6 in advance, and the lead frame 1 is welded through the low melting point glass 6 by raising the temperature to a certain level. Conventionally, amorphous glass is often used as the low melting point glass 6 in order to keep the temperature as low as possible during final cap sealing. After the lead frame is fixed, the small piece 4 can be removed by pulling it using the small hole 5. After this, pellets are mounted on the island section 7, but normally
When using Au-Si brazing material, the case should be 430~
It is necessary to heat it to about 450℃. At this time, the conventional structure has the disadvantage that the amorphous low melting point glass 6 becomes softened, causing the inner lead tip 3 to become misaligned. In reality, as shown in Figure 3, when the lead frame was fixed using a push-back type lead frame and the small pieces were removed, the inner lead tips, which were in position 3a without any displacement, changed to the position shown in 3b when mounted. It has the disadvantage of causing misalignment. This causes problems such as the inability to perform automatic bonding in the subsequent bonding process.

In order to eliminate the drawbacks of the conventional structure, this invention uses a push-back type lead frame, from the lead frame fixing process to the end of the pellet mounting process.
The present invention provides a glass-sealed case with no lead shift. An embodiment based on the present invention will be described with reference to FIGS. 4a and 4b. In fixing the pushback type lead frame 1 to the ceramic substrate 8, crystalline low melting point glass 9 is used only for the inner lead tip portion 3, and amorphous low melting point glass 6 is used for the other lead portions. This can be done by applying crystalline low melting point glass only to the portion corresponding to the tip of the inner lead and applying amorphous low melting point glass to the remaining portion when applying glass to the ceramic base 8 in advance. good. As an example, if part 9 is coated with crystalline glass Corning 7583 (a product of Corning Inc.) and part 6 is coated with amorphous glass LS-113 glass (a product of Nichiden Glass), The pushback type lead frame 1 is set in a predetermined position and heat treated at 480-500°C for about 5 minutes. As a result, the glass in the 7583 glass portion crystallizes. Therefore, there is an advantage that the crystallized glass 9 will not be softened by the heat treatment during pellet mounting, and the inner lead tip portion 3 will not be displaced. After pellet mounting, a cap coated with LS-113 glass can be used in the final sealing process, allowing sealing with a conventional low-temperature profile.

As described above, the glass-sealed case based on the present invention uses a push-back lead frame.
There is no displacement of the inner lead tip position when the lead frame is fixed, and since crystalline glass is interposed only at the lead tip, there is no displacement of the inner lead tip position when pellet mounting, making automatic bonding easy. has advantages. Also, the final cap sealing step has the advantage that it can be sealed with a conventional low temperature profile.

[Brief explanation of the drawing]

FIG. 1a is a partially omitted perspective view of the pushback type lead frame, and FIG. 1b is a plan view of the central portion of FIG. 1a. Figure 2a is a plan view of the central part of a conventional glass-sealed case;
Figure b is a sectional view of Figure 2a. FIG. 3 is a plan view showing the positional deviation of the inner leads of a conventional glass-sealed case. FIG. 4a is a plan view of the central part of a glass-sealed case based on an embodiment of the present invention, and FIG. 4b is a sectional view of FIG. 4a. In the figure, 1...Pushback type lead frame, 2...Tie bar portion, 3...Inner lead tip, 4...Small piece, 5...Small hole, 6...
Amorphous low melting point glass, 7... Island portion, 8...
...Ceramic substrate, 9...Crystalline low melting point glass.

Claims (1)

[Scope of utility model registration request] In a glass-sealed case formed by fixing a lead frame in which the inner lead tip and a small punched piece surrounded near the inner lead tip are returned to the state before punching, the inner lead tip of the lead frame is fixed. A glass-sealed case characterized in that only one part is fixed with crystalline glass, and the other parts are fixed with amorphous glass.