JP3466292B2 - Semiconductor package - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor package, and more particularly to a box-shaped semiconductor package for accommodating semiconductor elements such as optical elements.

[0002]

2. Description of the Related Art A conventional semiconductor package is shown in FIG.
Will be explained. The semiconductor package 50 is a box-shaped case including a plate-shaped base 52 on which a semiconductor element (not shown) is mounted, and a frame body 54 mounted on the base 52 by brazing to accommodate the semiconductor element. 56 is provided. Further, the base 52 is provided with a fixing portion 58 for fixing the case 56 to the surface of another mounting member such as a mounting board. The fixing portion 58 is formed at an end portion of the base 52 that is not covered by the frame body 54 when the frame body 54 is mounted on the base 52, and further has four holes 60 for inserting the mounting screws. It is set up. Further, a long groove 62 is formed in the frame body 54, and a ceramic terminal 66 having a signal line 64 for electrically connecting the semiconductor element mounted on the base 52 and the outside is attached to the long groove 62. Further, in consideration of the heat generation of the mounted semiconductor element, the base 52 is made of a copper-tungsten alloy having a high thermal conductivity or a copper-molybdenum-copper composite metal material. Further, as the material of the frame body 54, a metal material or a ceramic material having a metallized layer formed on the surface is used for brazing.

[0003]

However, the above conventional semiconductor package has the following problems. Since the fixing part for fixing the semiconductor package to the surface of another mounting member is provided at the end of the base for mounting the semiconductor element, this area cannot be used for mounting the semiconductor element, Usage efficiency decreases. In particular, as mentioned above, the base is made of copper
Since an expensive metal material such as a tungsten alloy or a copper-molybdenum-copper composite metal material is used, there is a problem that a decrease in utilization efficiency leads to an increase in product price. Also, when fixing the semiconductor package to the surface of another mounting member by screwing it using the holes in the fixing part, when the screw is tightened, stress is applied to the base that directly abuts the screw, the base warps, and it is mounted on the base. There is also a problem that the cracked semiconductor element may be cracked. Therefore, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to improve the utilization efficiency of a base, and to prevent the semiconductor package from being stressed when fixed to the surface of another mounting member. To provide.

[0004]

The present invention has the following constitution in order to achieve the above object. That is, in a semiconductor package including a case provided with a plate-shaped base on which a semiconductor element is mounted and a frame, and a plate-shaped fixing portion for fixing the case to the surface of another mounting member, The fixing portion, which is formed as a separate body and is extended by being joined to the case, elastically deforms and absorbs the stress applied to the base, so that the base can be prevented from warping or distortion. It is characterized in that it is formed thinner than the thickness of the frame body. By adopting this configuration, it is not necessary to provide a fixing portion on the base, and the outer shape of the base can be made closer to the outer shape of the bottom surface of the case. Therefore, the utilization efficiency of the base is improved and the product cost can be reduced. Further, when the fixing portion is fixed to the surface of another mounting member by using a screw or the like, the stress applied from the screw or the like can be deformed and absorbed by the fixing portion thinner than the base and the frame, and the stress on the base is reduced. It is possible to prevent cracks from entering the semiconductor element mounted on the base.

[0005]

Furthermore, the fixed portion, the side wall of the case
When the bottom surface of the case is brought into contact with the surface of another mounting member, the fixing portion is fixed by a screw or the like. Since it can be moved toward the surface of another mounting member, the case can be reliably pressed against the surface of another mounting member to be fixed.

If the fixing portion is made of an iron-nickel-cobalt alloy, it can be elastically deformed and the material cost can be reduced.

Further, if a copper-tungsten alloy or a copper-molybdenum-copper composite metal material is used for the base, since these metal materials have high thermal conductivity, the heat generated by the mounted semiconductor element is reduced. Can be efficiently radiated to the outside. Further, even if these expensive metal materials are used, the utilization efficiency of the base is improved, so that it is possible to suppress an increase in product cost.

[0009]

Since the fixing portion is formed separately from the case and is joined to the case, it is not necessary to provide the fixing portion on the base. Therefore, the outer shape of the base can be made closer to the outer shape of the bottom surface of the case, so that the utilization efficiency of the base is improved and the product cost can be reduced. Further, when the fixing portion is fixed to the surface of another mounting member using a screw or the like, the stress applied from the screw or the like can be deformed and absorbed by the fixing portion thinner than the base and the frame, and the stress on the base is reduced. Warp of the base
As a result, it is possible to prevent the semiconductor element mounted on the base from cracking.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of a semiconductor package according to the present invention will be described in detail below with reference to the accompanying drawings. First, the configuration of the semiconductor package 10 will be described with reference to FIG. Reference numeral 12 denotes a plate-shaped base on which a semiconductor element (not shown) is mounted, and in order to efficiently dissipate heat generated by the mounted semiconductor element to the outside, a copper-tungsten alloy or copper having high thermal conductivity. It is formed by using a composite metal material of molybdenum-copper. A metal frame 14 is mounted on the base 12 to accommodate the semiconductor element. A semiconductor element mounted on the base 12 inside the frame body 14 is hermetically sealed by a cap (not shown) attached to the upper surface of the frame body 14 to be opened. Instead of metal, a ceramic material having a metallized layer formed on the brazed portion may be used. Further, a long groove 62 is formed in the frame body 14 similarly to the conventional example, and a ceramic terminal 66 in which a signal line 64 for electrically connecting a semiconductor element mounted on the base 12 and the outside is formed in the long groove 62. Is attached. The frame 14 is attached to the plate-shaped base 12 described above to form the case 16. That is, the case
A base 12 and a frame 14 are provided at 16.

Reference numeral 18 denotes a fixing portion for fixing the case 16 composed of the base 12 and the frame body 14 to the surface of another mounting member, which is separate from the base 12 and the frame body 14 and is, for example, the base 12 or the frame body. 14 forming a metal material (thickness: 0.
8 to 1.0 millimeter order) are formed in an L-shape by bending a thin plate-like body (thickness of about 0.2 to 0.3 mm) than. By using a thin plate, it can be elastically deformed, and in particular, in the present embodiment, a relatively inexpensive iron-nickel-cobalt alloy is used in consideration of the price. Further, the fixing portion 18 is provided with a hole 20 for screwing. In addition, instead of the shape of the fixed portion 18 being L-shaped,
It may be appropriately changed according to the shape of the surface of another mounting member for fixing the semiconductor package 10, such as forming a rectangular parallelepiped. Further, the fixing portion 18 may be provided with a notch groove instead of the screwing hole 20.

Next, the assembly structure of the semiconductor package 10 will be described with reference to FIGS. As shown in FIG. 1, the frame body 14 is brazed and fixed to the upper surface of the base 12 by a brazing material 22 to form a case 16, and four fixing portions 18 are provided from the side of the frame body 14 and the base 12. The semiconductor package 10 is completed by brazing so as to be in contact with the end face. After that, although not shown, the frame 1
4, the semiconductor element is mounted in the housing 4, and the upper surface of the frame 14 is sealed by a cap. Finally, the semiconductor package 10 is fixed by screwing it onto the surface of another mounting member using the hole 20 of the fixing portion 18. To be done.

The fixing portion 18 contacts the screw and receives stress from the screw when tightening the screw, but is formed separately from the base 12 and fixed to the base 12 and the frame body 14 by brazing. By elastically deforming, the stress can be absorbed and the base 12 can be prevented from warping or distorting, so that the semiconductor element mounted on the base 12 is not damaged. Further, the fixed portion 18 is the base 12
Since it is formed as a separate body, it is only necessary to change the position where the fixing portion 18 is brazed to the base 12 or the frame body 14 even if the screwing position changes due to the surface shape of other mounting members. There is also an effect that it can be dealt with easily.

Further, as shown in FIG. 2, the end portion of the fixing portion 18 where the hole 20 is provided floats from the bottom surface of the base 12 by a minute distance L, that is, the fixing portion 18 moves from the bottom surface of the case 16 by a minute distance L. So that it extends from the spaced side walls,
The fixing portion 18 may be brazed to the side wall of the case 16 with the brazing material 22. With this configuration, the case 1
Even after the bottom surface of 6 (which is also the bottom surface of the base 12) comes into contact with the surface of another mounting member, the fixing portion 1 is fixed by tightening the screw.
Since 8 can be moved toward the surface of another mounting member, the semiconductor package 10 can be fixed to the surface of another mounting member. Further, when the fixing portion 18 is formed in a rectangular parallelepiped shape instead of the L shape, the end surface may be brazed to the base 12 or the frame body 14 as shown in FIG.
When the fixing portion 18 is formed in a rectangular parallelepiped, the end portion of the fixing portion 18 having the hole 20 is fixed to the bottom surface of the base 12 by brazing without floating from the bottom surface of the base 12, as shown in FIG. It may be done.

Although various preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the fixing portion is brazed only to either the base or the frame. The structure may be In particular, when brazing to the frame , even if the stress received by the fixing part from the screw cannot be absorbed only by the elastic deformation of the fixing part, the frame
The effect is that the body can absorb the stress and reduce the stress applied to the base. When the surface of the other mounting member is formed to be flat, the end of the fixing portion provided with the holes may be flush with the bottom surface of the base. With this configuration, the bottom surface of the base can be brought into close contact with the surface of the surface of another mounting member, and the heat generated from the semiconductor element can be efficiently transferred to the surface of the other mounting member via the base. In addition, as the case, the one in which the base and the frame are integrally formed may be used instead of the one in which the frame is attached to the base, and many modifications are made without departing from the spirit of the invention. Of course you get.

[0016]

When the semiconductor package according to the present invention is used, the fixing portion is formed separately from the frame body and the base,
Since the structure is joined by brazing, it is not necessary to provide a fixing portion on the base, and the outer shape of the base can be made closer to the outer shape of the bottom surface of the frame body. As a result, the amount of copper-tungsten alloy or copper-molybdenum-copper composite metal material generally used as a base can be reduced, and the product cost can be reduced. Also, if the fixing part is formed in a thin plate shape and is elastically deformable, the stress applied from the screw when the fixing part is screwed can be absorbed by the fixing part, the warp of the base can be prevented, and the base can be prevented from warping. It is possible to prevent damage to the mounted semiconductor element, and it is possible to improve the quality of the product.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a configuration of a semiconductor package according to the present invention.

FIG. 2 is an enlarged view of a partly cutaway main part showing a structure of a connecting part of a fixed part, a case and a base of FIG.

FIG. 3 is a partially cutaway enlarged view showing a structure for joining a fixed portion of a rectangular parallelepiped to a base.

FIG. 4 is a partially cutaway enlarged view showing a structure for joining a fixing portion to a bottom surface of a base.

FIG. 5 is an exploded perspective view showing a configuration of a conventional semiconductor package.

[Explanation of symbols]

10 Semiconductor package 12 base 14 frame 16 cases 18 Fixed part

   ─────────────────────────────────────────────────── ─── Continued front page       (56) Reference JP-A-10-224145 (JP, A)                 JP-A-3-85907 (JP, A)                 Actual Kaihei 1-80944 (JP, U)                 Actual Kaihei 5-11443 (JP, U)                 Actual Kohei 4-38523 (JP, Y2)

Claims (4)

(57) [Claims] 1. A semiconductor package comprising a case having a plate-shaped base on which a semiconductor element is mounted and a frame body, and a plate-shaped fixing portion for fixing the case to the surface of another mounting member. The fixing portion, which is formed separately from the case and is joined and extended to the case, elastically deforms and absorbs the stress to the base, so that the base can be prevented from warping or distortion . A semiconductor package, which is formed thinner than the thickness of the base and the frame. 2. The semiconductor package according to claim 1, wherein the fixing portion is joined to a side wall of the case and extends at a position separated from the bottom surface of the case by a predetermined distance. 3. The fixing portion is formed by using an iron-nickel-cobalt alloy.
Alternatively, the semiconductor package described in 2. 4. The base is a copper-tungsten alloy,
4. A semiconductor package according to claim 1, 2 or 3, which is formed using a composite metal material of copper-molybdenum-copper.