JP2811021B2 - Semiconductor package and manufacturing method thereof - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor package for accommodating a semiconductor element and a method for manufacturing the same.

[Conventional technology]

As shown in FIG. 8, the package for housing the semiconductor element is composed of an insulating base 21 made of a ceramic material such as alumina, a lid 22, and external lead terminals 23, as shown in FIG. . Then, a fixing material 25 such as gold (Au) is applied to the bottom surface of the cavity portion 21a of the insulating base 21 to fix the semiconductor element 24, and each electrode of the semiconductor element 24 is connected to the external lead terminal 23 by a wire 26. After the connection, the lid 22 was covered, and the glass layers 27a and 27b were heated and melted, and then hermetically sealed by integrating them.

[Problems of the prior art]

In the above semiconductor package, the number of external lead terminals 23 was about 28, but in recent years it has increased to 40 or 48. Along with this, it is necessary that the length of the insulating base 21 and the lid 22 in the long side direction constituting the semiconductor package be as long as 50 mm or more.

However, the insulating substrate 2 having a long side length of 50 mm or more
1.When the lid 22 is made of ceramic,
The occurrence of warpage of about m was inevitable.

Therefore, as shown in the cross-sectional view in the long side direction of FIG.
If warpage occurs so that the sealing surfaces of the insulating base 21 and the lid 22 are convex, the glass layers 27 are likely to open at both ends during glass sealing, and there is a problem that poor sealing is likely to occur.

[Means for solving the problem]

In view of the above, the present invention prevents an end portion from opening at the time of glass sealing by previously forming a sealing surface of an insulating base and / or a lid constituting a ceramic package as a concave curved surface.

In addition, the concave curved surface in the present invention is a shape in which the central portion is smoothly depressed as compared with the end portion, but in the case of a rectangular package, at least the central portion is depressed along the long side direction. It just needs to be.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in the cross-sectional view in the long side direction in FIG. 1, the insulating base 1 constituting the semiconductor package of the present invention has a cavity 1a.
Is a concave curved surface having a depth x. On the other hand, the sealing surface 2a of the lid 2 is also a concave curved surface having a depth of y, and when both are sealed with glass, the ends do not open.

In the above embodiment, both the sealing surfaces 1b and 2a of the insulating base 1 and the lid 2 are concave curved surfaces, but only one of them may be a concave curved surface and the other may be a flat surface.

Further, the depths x and y of the concave curved surfaces may be in the range of 0 to 100 μm, respectively. When both the sealing surfaces 1 b and 2 a of the insulating base 1 and the lid 2 are concave curved surfaces, Depth x, y
May be set to be 0 to 100 μm.

In order to manufacture the insulating base 1 and the lid 2 having the shapes shown in FIG. 1, as shown in FIG.
12, in a press forming apparatus including the first lower punch 13 and the second lower punch 14, the pressing surface of the first lower punch 13 is made convex, the ceramic raw material powder 15 is press-formed, and the obtained formed material is fired. It can be manufactured by doing.

 Next, another embodiment of the present invention will be described.

As shown in the cross-sectional view in the long side direction in FIG. 3, the insulating base 1 constituting the semiconductor package of the present invention has a cavity portion.
The sealing surface 1b on the side where 1a is formed is a concave curved surface having a depth x, and a height of 100 around the cavity 1a of the sealing surface 1b.
A plurality of minute projections 1c of not more than μm are formed. On the other hand, the sealing surface 2a of the lid 2 is a flat surface, and when both are sealed with glass, the ends do not open.

Further, similarly to the above-described embodiment, the sealing surfaces 1b and 2a of both the insulating base 1 and the lid 2 are formed as concave curved surfaces, or only the sealing surface 2a of the lid 2 is formed as a concave curved surface. The sealing surface 1b may be a flat surface.

In this case, the depth x of the concave curved surface may be set to 0 to 100 μm similarly to the above-described embodiment, and when both the sealing surfaces 1b and 2a of the insulating base 1 and the lid 2 are concave curved surfaces, both are set. May be set so that the sum of the depths becomes 0 to 100 μm.

Here, a method of manufacturing the insulating base 1 shown in FIG. 3 will be described.

First, as shown in FIG. 4, a ceramic raw material powder 15 is press-formed using a press forming apparatus including a die 11, an upper punch 12, a first lower punch 13, and a second lower punch 14 (FIG. 3). And upside down). At this time,
The pressing surface of the first lower punch 13 is a flat surface, and has a minute concave portion 13a in the center.

Accordingly, the molded body press-molded in this manner has a shape having a flat sealing surface 1b and a projection 1c at the center as shown in FIG. 5 (a). When the unsintered insulating base 1 is placed on the shelf 16 with the projection 1c facing down and fired, the end thereof sags during firing.
As shown in FIG. 2B, the sealing surface 1b of the insulating substrate 1 has a concave curved surface. In addition, since the depth x of the concave curved surface at this time is the same as the height of the projection 1c, the depth x of the concave shape can be freely adjusted by adjusting the height of the projection 1c.

In addition, although the projection 1c remains on the sealing surface, glass is applied to a height equal to or higher than the height of the projection 1c, so that no problem occurs at the time of sealing. Rather, at the time of screen printing of glass, the projections 1c serve as a measure of the height, and there is an effect that variation in the glass thickness can be reduced.

Further, in this embodiment, as shown in FIG. 3, the back surface 1d of the cavity portion 1a of the insulating base 1 has a convex curved surface. This is very convenient because the heat of the heater which is brought into contact from below to melt the heat is easily transmitted.

Further, in this embodiment, since the cavity portion 1a becomes the lower surface during firing as shown in FIGS. 5 (a) and 5 (b), it is possible to prevent dust and the like from adhering to the inside of the cavity portion 1a and to prevent the cavity portion 1a from being attached. Since the back surface 1d does not come into contact with the shelf 16, scratches are less likely to occur, and further, there are effects such as a plurality of molded bodies that can be stacked and fired.

The shape of the protrusion 1c may be such that four round protrusions 1c are formed around the cavity 1a as shown in FIG. 6 (a), or as shown in FIG. 6 (b). It is sufficient to form two elliptical protrusions 1c on both sides of the cavity 1a.

 Further, another embodiment of the present invention will be described.

In the embodiment shown in FIG. 3, the protrusion 1c is formed around the cavity 1a of the insulating base 1.
A protrusion may be formed at the end of the back surface 1d of 1a. For example, as shown in FIG.
Press-molded so as to have a projection 1c at the end of the molded body, the molded body is placed on a shelf plate 16 with the projection 1c facing down, and if fired, the sealing surface 1b is depressed at the center portion. Can be a concave curved surface.

Also in this case, similarly to the above embodiment, a plurality of molded bodies can be stacked and fired, and when used as a semiconductor package, the marking formed on the back surface 1d is not easily peeled off.

Further, as shown in FIG. 7 (b), the entire back surface 1d is formed into a concave curved surface so that the end of the back surface 1d of the insulating base 1 becomes a protruding shape, and when this surface is fired, the center The portion may be depressed and the sealing surface 1b may be a concave curved surface.

Next, a prototype of the semiconductor package of the present invention shown in FIG. 3 was manufactured, and the lid 2 was sealed with glass by changing the depth x of the concave curved surface of the sealing surface 1b of the insulating base 1, and a helium leak test was performed. The occurrence rate of defects when the test was performed was examined. The insulating substrate 1 was made of black alumina ceramic and had a long side with a length of 52 mm.

As shown in Table 1, the results are as follows.
Those with μm showed excellent results.

Also, what is shown in the above embodiment is a rectangular package, and it is sufficient that the sealing surface has a concave curved surface at least in the long side direction, but in the case of a rectangular package,
It is necessary to make the sealing surface a concave curved surface in two directions perpendicular to each other. Generally, when the length of the side is 30 mm or more, the sealing surface may be formed as a concave curved surface in the side direction.

〔The invention's effect〕

As described above, according to the present invention, the sealing surface of the insulating base and / or the lid constituting the semiconductor package is made to have a concave curved surface, thereby completely preventing the sealing failure due to the opening of the end portion during glass sealing. can do. In addition, as a method of manufacturing the insulating substrate and the lid, a molding is performed so as to have a projection at the center of the sealing surface or an end of the back surface, and the molded body is placed and fired with the projection facing down. This makes it possible to form the concave curved surface efficiently and efficiently because a plurality of the layers can be stacked and fired.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an insulating base and a lid constituting a semiconductor package according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a press forming apparatus for forming the insulating base or the lid shown in FIG. FIG. 3 is a sectional view showing an insulating base and a lid constituting a semiconductor package according to another embodiment of the present invention. 4th
The figure is a sectional view showing a press forming apparatus for forming the insulating base shown in FIG. 5 (a) and 5 (b) are views showing a firing step of the insulating substrate shown in FIG. 3, and FIG. 6 (a)
FIG. 2B is a plan view of the insulating base. 7 (a) and 7 (b) are cross-sectional views showing an unfired shape of an insulating base constituting a semiconductor package according to still another embodiment of the present invention. FIG. 8 is a sectional view in the short side direction of a general semiconductor package. FIG. 9 is a longitudinal sectional view of a conventional semiconductor package. 1: Insulating substrate, 1a: Cavity part 1b: Sealing surface, 1c: Projection 1d: Back surface 2: Lid, 2a: Sealing surface

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 23/02 H01L 23/08

Claims (3)

(57) [Claims] 1. A semiconductor package comprising an insulating base in which a cavity for accommodating a semiconductor element is formed, and a lid for sealing the cavity, wherein a sealing surface of the insulating base and / or the lid is sealed. A semiconductor package having a concave curved surface. 2. The semiconductor device according to claim 1, wherein the insulating base and / or the lid have a plurality of minute projections at a peripheral portion of the cavity on the sealing surface or at an end of the back surface of the sealing surface. The semiconductor package as described. 3. The ceramic raw material powder is press-molded so as to have a cavity on one side of the plate-like body and to have a projection on the periphery of the cavity or on the end of the back surface of the cavity. A method of manufacturing a semiconductor package, wherein a molded body is placed on a shelf plate so that the projections face down and fired, so that a sealing surface of an insulating base or a lid is formed into a concave curved surface.