JP7190934B2 - Can package cap - Google Patents

Description

The present application relates to a can package cap.

The stem to which the semiconductor chip is fixed is sealed with a can package cap. This cap is normally used to protect or hermetically seal the semiconductor device mounted on the stem. At this time, it is common to join a metal cap to the stem by resistance welding. be. When the semiconductor chip fixed to the stem is a light-emitting semiconductor such as a laser diode or a light-receiving semiconductor such as a photodiode, the cap emits light emitted from the semiconductor to the outside of the cap, or emits external light. There may be an entrance opening or lens inside the cap.

Some conventional caps are configured to have two or more closed annular projections (hereinafter referred to as protrusions) for resistance welding (see, for example, Patent Document 1).
In addition, in the conventional cap, an annular projection for resistance welding and an annular groove recessed on the inner peripheral side of the projection in the opposite direction to the projection direction of the projection are concentrically formed by press working. Some have a formed configuration (see, for example, Patent Document 2).

JP 2010-40647 A JP 2010-34287 A

In the case of the configuration of Patent Document 1, by providing two or more protrusions, an improvement in airtightness can be expected. There is a possibility that molten metal generated during welding may fly out.

In the case of the configuration disclosed in Patent Document 2, there is only one protrusion that contributes to welding, so there is a possibility that sufficient welding strength or long-term reliable airtightness cannot be obtained. In addition, as in Patent Document 1, a protrusion that contributes to welding is formed in the vicinity of the edge of the flange, and there is a possibility that molten metal generated during resistance welding may protrude to the outside. In addition, due to the presence of the annular groove with the V-shaped cross section, a load cannot be uniformly and perpendicularly applied to the protrusion during resistance welding, which may result in poor welding. In addition, since the upper surface of the flange forms an uneven shape and is not flat, there is a possibility that the upper surface of the flange cannot be used.

The present application discloses a technique for solving the above-described problems, improving the welding strength of the flange portion of the can package cap and the airtightness of the internal space of the cap, and increasing the resistance of the flange portion. To provide a cap for a can package capable of keeping the upper surface of a flange flat by eliminating protrusion of molten metal during welding.

The cap of the stem disclosed in the present application comprises:
A can package cap covering a semiconductor element mounted on a stem,
a tubular portion, and a flange portion provided on one end surface side of the tubular portion and fixed to the stem,
The flange portion has, on the surface thereof facing the stem, an annular projection portion which is wavy around the extension of the outer peripheral contour line of the cylindrical portion.

According to the can package cap disclosed in the present application, the welding strength of the flange portion of the can package cap and the airtightness of the internal space of the cap are improved, and melted meat is prevented from protruding when the flange portion is resistance welded. It is possible to provide a can package cap capable of keeping the upper surface of the flange flat by eliminating the .

2 is a schematic diagram showing a cross section of the can package cap of Embodiment 1. FIG. 2 is an enlarged cross-sectional view of the periphery of the flange portion of the can package cap of FIG. 1; FIG. 2 is a schematic view of the can package cap of Embodiment 1 as viewed from the bottom; FIG. FIG. 4 is a schematic diagram showing a cross section of a can package cap according to Embodiment 2; FIG. 10 is a schematic view of the can package cap of Embodiment 2 as viewed from the bottom; FIG. 11 is a partially enlarged view of an annular projection when the can package cap of Embodiment 3 is viewed from the bottom; FIG. 12 is a schematic view of the can package cap of Embodiment 4 as viewed from the bottom;

Embodiment 1.
The can package cap of Embodiment 1 will be described below with reference to the drawings.
1 to 3 are schematic diagrams for explaining the can package cap of the first embodiment. FIG. 1 is a cross-sectional view for explaining an outline of a can package cap 1, a semiconductor element 3, and a stem 2 that holds the semiconductor element 3. FIG. and FIG. 3 is a bottom view of the can package cap 1. As shown in FIG.

As shown in FIG. 1, the can package cap 1 includes a lens 1a, a flange portion 1b, and an annular projection portion 1c as components. Here, the can package cap 1 has a lens 1a provided on the upper part of a cylindrical main body, and forms a hat shape with a flange portion 1b which is a fixing portion fixed to a stem 2 on which a semiconductor element 3 is mounted. (See Figure 1).
Further, as shown in FIGS. 1 to 3, an annular protrusion 1c for resistance welding is provided on the bottom surface of the flange portion 1b. As shown in FIGS. 1 and 2, the annular protrusion 1c has a triangular cross section, and as shown in FIG. is fixed to the stem 2 by resistance welding on the outside of the two sides forming the . As shown in the bottom view of FIG. 3, when viewed from the bottom, the shape of the contour line (formed by the curve connecting the three vertices of the triangular figure) is concentric. It is formed by three wavy circular curves. In addition, as shown in FIG. 2, it can be seen that the resistance welded portion W is the outer portion of two sides that intersect at the tip of the triangular cross section.

Here, in resistance welding the can package cap 1 of Embodiment 1 to the stem 2, the tip of the annular protrusion 1 c of the can package cap 1 (the curved line 1 c ₁ connecting the ends) is placed on the upper surface of the stem 2. By pressing, the annular protrusion 1c functions as a contact resistance.

The annular protrusion 1c has a shape of an outer contour line viewed from the bottom surface, which is a circular shape in which the reference curve is deformed into a sinusoidal shape (in other words, a sinusoidal shape), for example. Therefore, it is possible to widen the joint area where the annular protrusion 1c joins the stem 2, thereby improving the welding strength of the flange portion and the airtightness of the inside of the can package cap 1. can be improved.

Embodiment 2.
The can package cap of the second embodiment will be described below with reference to the drawings.
In the first embodiment, the case where the cross-sectional shape of the wavy annular projection 1c when viewed from the surface of the flange portion 1b of the can package cap is composed of one triangle has been described. As shown, it may be an annular protrusion 1d in which two triangles partially overlap each other.

In this case, as shown in FIG. 5, when viewed from the bottom, the annular protrusion 1d has an outer outline formed by five concentrically wavy annular curves. .

Here, in resistance welding the can package cap 1 of the second embodiment to the stem 2, two points of the outer shape line of the annular protrusion 1d of the can package cap 1 are attached to the upper surface of the stem 2, connecting the tips. By pressing the wavy curves 1d ₁ and 1d ₂ , the annular protrusion 1d functions as a contact resistance.

The shape of the outline of the annular protrusion 1d as viewed from the bottom surface is a circle as a reference curve, and the reference curve is deformed to form, for example, two wavy curves 1d ₁ connecting the sinusoidally wavy tips. , 1d and ₂ , and the joint area where the annular protrusion 1d joins the stem 2 is wider than that of the first embodiment. As a result, the welding strength of the flange portion and the airtightness of the inside of the can package cap 1 can be improved.

Embodiment 3.
The can package cap of the third embodiment will be described below with reference to the drawings.
In the second embodiment, when viewed from the surface of the flange portion 1b of the can package cap,
The description has been made on the assumption that the two wavy annular curves 1d ₁ and 1d ₂ connecting the tips have the same shape (similarity) to each other. As shown in , when viewed from the bottom, the two wavy circular curves connecting the points are not similar to each other. It is characterized by

Specifically, as shown in FIG. 6, between two wavy annular curves 1e ₁ and 1f ₁ connecting the tips formed by the annular projections 1e and 1f, respectively, the outermost (i.e. It is characteristic that the values of the amplitude of the undulations of the annular curve _1f1 in some parts (larger outer diameter) are larger than in other places.

In this case, as shown in FIG. 6, the annular projections 1e and 1f form a sealed space S at a location where the amplitude value of a portion of the undulation of the annular curve _1f1 is greater than the other locations. Form.

Here, in resistance welding the can package cap 1 of Embodiment 3 to the stem 2, two wavy lines connecting the tips of the annular protrusions 1 e and 1 f of the can package cap 1 are formed. By pressing the curves 1e ₁ and 1f ₁ against the upper surface of the stem 2, the annular protrusions 1e and 1f function as contact resistance.

Compared to the second embodiment, the annular projection 1f has a longer annular curve. It becomes possible to widen it, and it becomes possible to improve the welding strength of the flange portion. In addition, the presence of the sealed space S can further improve the airtightness inside the can package cap 1 .

Embodiment 4.
The can package cap of the fourth embodiment will be described below with reference to the drawings.
In Embodiment 2, the case where the cross-sectional shape of the wavy annular projection 1d has a shape in which two triangles partially overlap each other has been described. When viewed from the bottom surface of the flange portion 1b of the can package cap, the protrusion 1g may be circular instead of the wavy annular protrusion.

In this case, as in the case of the second embodiment, the cross-sectional shape (not shown) of the protrusion 1g is a shape in which two triangles partially overlap each other.

In the can package cap of the fourth embodiment, as in the case of the second embodiment, when the can package cap 1 is resistance-welded to the stem 2, two circular can packages are formed on the upper surface of the stem 2. By pressing the curves 1g ₁ and 1g ₂ connecting the tips of the protrusions 1g of the cap 1, the cap 1 functions as a contact resistance.

In the case of this projecting portion 1g, it is possible to improve the welding strength of the flange portion as compared with the conventional one. Further, in addition to having the characteristic of being able to further improve the airtightness, compared with the case of the second embodiment, since the curves 1g ₁ and 1g2 connecting the tips of the projections 1g are circular, the projections is easy to manufacture.

While this application describes various exemplary embodiments and examples, various features, aspects, and functions described in one or more embodiments may not apply to particular embodiments. can be applied to the embodiments singly or in various combinations.
Therefore, countless variations not illustrated are envisioned within the scope of the technology disclosed herein.

1 can package cap, 1a lens, 1b flange, 1c, 1d, 1e, 1f annular projection, 1g projection, 2 stem, 3 semiconductor element, S closed space, W resistance welding part

Claims (4)

A can package cap covering a semiconductor element mounted on a stem,
a tubular portion, and a flange portion provided on one end surface side of the tubular portion and fixed to the stem,
A cap for a can package, wherein the flange portion has, on a surface facing the stem, an annular projection portion which is wavy around an extension line of an outer peripheral contour line of the cylindrical portion. 2. The can package cap according to claim 1, wherein the annular protrusion is formed by overlapping a plurality of annular protrusions having different outer diameters concentrically in the radial direction at least partially. Among the two annular projections having different outer diameters formed concentrically around the extension of the outer peripheral contour line of the cylindrical portion, the annular projection having the larger outer diameter has an amplitude of undulation. 3. The can package according to claim 2, wherein at least part of is different from the amplitude of undulation other than part of the amplitude of the undulation, thereby forming a closed space between the annular projections having different outer diameters. cap. A can package cap covering a semiconductor element mounted on a stem,
It is composed of a cylindrical portion to which a lens is attached, and a flange portion provided on one end surface side of the cylindrical portion and fixed to the stem,
The flange portion has, on the surface facing the stem, a projection formed in a circular shape around the extension of the outer peripheral contour line of the cylindrical portion, and the projection has a plurality of different outer diameters. A cap for a can package, characterized in that the projections of the can package are constructed so as to radially concentrically overlap each other at least partially.

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