JP2011049340A - Semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device capable of securing high reliability even at a high temperature by lowering a heat stress generated in a connection part at the change of temperature as much as possible in a structure where two kinds of materials, such as a semiconductor element and an electrode, are connected on surfaces. <P>SOLUTION: The semiconductor device includes: a semiconductor element; a first stress adjuster, which is connected with the semiconductor element via a connection member and on which holes are formed; a second stress adjuster where protrusions to be pressed into the holes are provided; and a heat conductive material filled in between the first stress adjuster and the second stress adjuster. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a semiconductor device, and more particularly to a power semiconductor device that operates at a high temperature.

  FIG. 5 is a view showing a cross section of a main part of an IGBT module as an example of a conventional power semiconductor device. In FIG. 5, 1 is a semiconductor element such as IGBT or FWD, 5 is a bonding material, 7 is an insulating substrate having a circuit formed on both sides by copper foil, 8 is a heat dissipation base, and 9 is an electrode. In addition, the outer case of the module is not omitted. As shown in FIG. 5, a semiconductor device (particularly a power semiconductor device) generally has a structure in which several parts including a semiconductor element are joined on a surface. Moreover, the semiconductor element has a very small linear expansion coefficient, and the electrode and the base often have a linear expansion coefficient several times that of the semiconductor element. Therefore, when a temperature change is given to the semiconductor device, thermal stress resulting from a difference in coefficient of linear expansion between the semiconductor element and the electrode is generated in the bonding material. When this thermal stress is repeatedly applied, the joint may be broken. As a structure for ensuring the reliability of the joint, Patent Document 1 discloses a structure in which a component having a linear expansion coefficient intermediate between the semiconductor element and the component is inserted to disperse the thermal stress. Patent Document 2 discloses a structure that reduces thermal stress by resin-sealing a joint.

JP 2005-56873 A JP 2006-179732 A

  In recent years, in the field of power semiconductors, there has been an increasing demand for operation in a higher temperature range than before, against the background of development of SiC elements and GaN elements. When the operating temperature of the power semiconductor device is increased, the thermal stress generated in the joint portion also increases. Therefore, in the structures disclosed in Patent Documents 1 and 2, the reliability of the joint portion cannot be sufficiently ensured at present. .

  The object of the present invention has been made in view of the above problems, and in a structure in which two kinds of materials such as a semiconductor element and an electrode are joined on the surface, the thermal stress generated at the joint when the temperature changes is reduced as much as possible. Another object is to provide a semiconductor device capable of ensuring high reliability even in a high temperature range.

  In order to solve the above problems, the present invention provides a semiconductor element, a first stress adjusting material connected to the semiconductor element via a bonding material and having a hole formed therein, and a protrusion press-fitted into the hole. A second stress adjusting material provided; and a heat conductive material filled between the first stress adjusting material and the second stress adjusting material. Further, a semiconductor element, a lead frame connected to the semiconductor element via a bonding material, a first stress adjusting material connected to the semiconductor element via a bonding material and having a hole formed therein, A second stress adjusting material provided with a protrusion press-fitted into the hole; an insulating substrate connected to the second stress adjusting material via a bonding material; and connected to the insulating substrate via a bonding material. And a heat conducting material filled between the first stress adjusting material and the second stress adjusting material. Furthermore, the linear expansion coefficient of the first stress adjusting material is smaller than the linear expansion coefficient of the second stress adjusting material. Furthermore, the linear expansion coefficient of the first stress adjusting material is 10 ppm / ° C. or less. Furthermore, the second stress adjusting material and the heat dissipation base are the same material. Further, the hole is formed in a central portion of the first stress adjusting material, and the protrusion is provided in a central portion of the second stress adjusting material. Further, the hole and the protrusion are provided in a region overlapping with the semiconductor element. Furthermore, the hole and the protrusion have a screw structure. Further, the hole does not penetrate the first stress adjusting material. A semiconductor element; a first stress adjusting material connected to the semiconductor element via a bonding material; and a hole formed therein; a second stress adjusting material provided with a protrusion press-fitted into the hole; The first stress adjusting material has a heat conductive material filled between the first stress adjusting material and the second stress adjusting material, and the first stress adjusting material is formed on both sides of the semiconductor element with the semiconductor element as an axis. The material, the heat conducting material and the second stress adjusting material are arranged symmetrically.

  According to the present invention, in a structure in which two kinds of materials such as a semiconductor element and an electrode are bonded on the surface, the thermal stress generated in the bonded portion when temperature changes is reduced as much as possible, and high reliability is ensured even in a high temperature range. It is possible to provide a semiconductor device capable of performing the above.

1 is a perspective view of a semiconductor device of Example 1. FIG. 1 is a plan view of a semiconductor device of Example 1. FIG. It is sectional drawing in the AA of FIG. 1 is an exploded perspective view of a semiconductor device of Example 1. FIG. It is principal part sectional drawing of the semiconductor device by a prior art. FIG. 6 is a cross-sectional view and a plan view of main parts of a semiconductor device of Example 2. FIG. 6 is a cross-sectional view and a plan view of a main part of a semiconductor device of Example 3. FIG. 10 is a cross-sectional view and a plan view of main parts of a semiconductor device according to Example 4; FIG. 10 is a main part sectional view of a semiconductor device according to Example 5; FIG. 16 is a cross-sectional view and a plan view of main parts of a semiconductor device according to Example 6. FIG. 10 is a main-portion cross-sectional view of a semiconductor device in Example 7. FIG. 10 is a main part sectional view of a semiconductor device in Example 8; FIG. 20 is a cross-sectional view and a plan view of main parts of a semiconductor device according to Example 9; FIG. 16 is a cross-sectional view and a plan view of main parts of a semiconductor device according to Example 10; FIG. 44 is a cross-sectional view and a plan view of main parts of a semiconductor device according to Example 11; FIG. 34 is a main-portion cross-sectional view of the semiconductor device of Example 12; FIG. 44 is a cross-sectional view and a plan view of main parts of a semiconductor device according to Example 13; FIG. 40 is a main-portion cross-sectional view of the semiconductor device of Example 14; FIG. 40 is a main-portion cross-sectional view of the semiconductor device of Example 15;

  FIG. 1 is a perspective view of the semiconductor device according to the first embodiment. The semiconductor device shown in FIG. 1 includes a semiconductor element 1, a first stress adjusting material 2, a second stress adjusting material 3, an electrode 4, a bonding material 5, and a heat conducting material 6. In addition, the outer case of the module is not omitted. FIG. 2 is a plan view of the semiconductor device according to the first embodiment. 3 is a cross-sectional view taken along line AA in FIG. FIG. 4 is an exploded perspective view of the semiconductor device according to the first embodiment. The semiconductor element 1, the first stress adjusting material 2, the second stress adjusting material 3 and the electrode 4 are respectively connected by a bonding material 5, and the first stress adjusting material 2 and the second stress adjusting material 3 are projected. 3a is mechanically connected by press-fitting into the hole of the first stress adjusting material 2, and a heat conducting material 6 is filled between them.

  Here, although Si is used for the semiconductor element 1, SiC or GaN may be used. Mo is used for the first stress adjusting material 2, but any material having a linear expansion coefficient of 10 ppm / ° C. or less may be used. W, Fe—Ni alloy, metal (Mo, W, Fe—Ni alloy) ) And Cu composite material (alloy, laminated material, mixed sintered material) or diamond may be used. The second stress adjusting material 3 and the electrode 4 are preferably made of the same material, and in Example 1, both are made of copper. Furthermore, it is preferable that the linear expansion coefficient of the second stress adjusting material 3 is larger than the linear expansion coefficient of the first stress adjusting material 2. The bonding material 5 uses an Ag sintered material, but it is Sn-Sb solder, Sn-Cu solder, Bi-Ag solder, Zn-Al solder, Ag or Cu brazing material, sintered. A material or a paste material may be used. Although the thermal conductive material 6 uses a thermal compound, a solder material or an Ag paste material may be used.

  FIG. 6 is a cross-sectional view and a plan view of the main part of the semiconductor device according to the second embodiment. 6 includes a lead frame electrode 9, a semiconductor element 1, a first stress adjusting material 2, a second stress adjusting material 3, an insulating substrate 7 having a circuit formed of copper foil on both surfaces of the insulating material, and a heat dissipation base. 8 is laminated, a heat conductive material 6 is filled between the first stress adjusting material 2 and the second stress adjusting material 3, and the other members are connected by a bonding material 5. In addition, the outer case of the module is not omitted. The difference from FIG. 1 is that the insulating substrate 7 and the lead frame electrode 9 are included in the structure, which is an example showing that the structure can be applied to an IGBT module or the like. At this time, the circuit 7a formed on the semiconductor element side of the insulating substrate 7 and the second stress adjusting material 3 may be integrated. In FIG. 6, the number of the holes of the first stress adjusting material 2 and the number of the protrusions of the second stress adjusting material 3 are four, but it is not necessary to be four. The shape of the holes and protrusions need not be cylindrical.

  FIG. 7 is a cross-sectional view and plan view of the main part of the semiconductor device according to the third embodiment. The difference from FIG. 6 is that the protrusion 3a connecting the first stress adjusting material 2 and the second stress adjusting material 3 is not in the vicinity of the outer periphery of the joint, but in the center of the joint (the center of the second stress adjusting material 3). In addition, only one is provided. Accordingly, the hole of the first stress adjusting material 2 is formed in the central portion of the first stress adjusting material 2. Thereby, the 1st stress adjustment material 2 is pulled by the thermal expansion of the 2nd stress adjustment material 3, and it can prevent that the 1st stress adjustment material 2 deform | transforms more than original thermal expansion.

  FIG. 8 is a cross-sectional view and plan view of the main part of the semiconductor device according to the fourth embodiment. The difference from FIG. 7 is that the protrusion 3b of the second stress adjusting material 3 is a screw, and the first stress adjusting material 2 and the second stress adjusting material 3 are fastened and connected by a screw structure. It is a point. Thereby, the assembly | attachment of the 1st stress adjusting material 2 and the 2nd stress adjusting material 3 can be simplified.

  FIG. 9 is a cross-sectional view and plan view of the main part of the semiconductor device of Example 5. The difference from FIG. 6 is that the protrusion 3 a of the second stress adjusting material 3 is arranged in a region overlapping the semiconductor element 1. Thereby, the heat generated in the semiconductor element 1 can be efficiently released to the heat dissipation base 8 on the second stress adjusting material 3 side. In FIG. 9, the number of the holes of the first stress adjusting material 2 and the number of the protrusions of the second stress adjusting material 3 are four, but it is not necessary to be four. The shape of the holes and protrusions need not be cylindrical.

  FIG. 10 is a fragmentary cross-sectional view of the semiconductor device of Example 6. The difference from FIG. 9 is that only one is arranged at the center of the joint. Thereby, the heat generated in the semiconductor element 1 can be efficiently released to the heat dissipation base 8 on the second stress adjusting material 3 side, and the thermal stress generated at the end of the bonding material can be reduced.

  FIG. 11 is a cross-sectional view and plan view of the main part of the semiconductor device according to the seventh embodiment. The difference from FIG. 10 is that the protrusion 3 a of the second stress adjusting material 3 is a screw and does not penetrate the first stress adjusting material 2. Thereby, deterioration of the bonding material 5 between the semiconductor element 1 and the first stress adjusting material 2 near the center can be prevented.

  FIG. 12 is a cross-sectional view of a principal part of the semiconductor device according to the eighth embodiment. The semiconductor device shown in FIG. 12 includes a heat dissipation base 8, an insulating substrate 7 having a circuit formed of copper foil on both sides of the insulating material, a second stress adjusting material 3, a first stress adjusting material 2, a semiconductor element 1, a first element. A stress adjusting material 2, a second stress adjusting material 3, an insulating substrate 7 having a circuit formed of copper foil on both sides of the insulating material, and a heat dissipation base 8 are laminated, and the first stress adjusting material 2 and the second stress adjusting material 3 are laminated. Between them, the heat conductive material 6 is filled, and the other members are connected by the bonding material 5. In addition, the outer case of the module is not omitted. A difference from FIG. 6 is that a pair of stress adjusting materials 2, 3, a pair of insulating substrates 7, and a pair of heat dissipation bases 8 are arranged so as to be symmetrical on both sides of the semiconductor element 1 as an axis. . This doubles the heat dissipation area, improving heat dissipation. In FIG. 12, the number of the holes in the first stress adjusting material 2 and the number of the protrusions in the second stress adjusting material 3 are two, but it is not necessary to be two. The shape of the holes and protrusions need not be cylindrical.

  FIG. 13 is a cross-sectional view of a principal part of the semiconductor device according to the ninth embodiment. The semiconductor device shown in FIG. 13 includes a lead frame electrode 9, a semiconductor element 1, an insulating substrate 7 having a circuit formed of copper foil on both surfaces of the insulating material, a first stress adjusting material 2, and a second stress adjusting material 3. The first stress adjusting material 2 and the second stress adjusting material 3 are filled with a heat conductive material 6 and the other members are connected by a bonding material 5. In addition, the outer case of the module is not omitted. The difference from FIG. 1 is that the structure includes an insulating substrate 7 and a lead frame electrode 9 and the heat dissipation base 8 is reduced. Even a structure different from FIG. 6 can be applied to an IGBT module or the like. It is an example which shows that there is. At this time, a fin for heat radiation may be provided on the side opposite to the surface on which the protrusion 3a is arranged so that the second stress adjusting material 3 can serve as a heat radiation base. In FIG. 13, there are four holes in the first stress adjusting material 2 and four protrusions in the second stress adjusting material 3, but it is not necessary to have four. The shape of the holes and protrusions need not be cylindrical.

  FIG. 14 is a cross-sectional view and plan view of the main part of the semiconductor device of Example 10. The difference from FIG. 13 is that only one protrusion 3a connecting the first stress adjusting material 2 and the second stress adjusting material 3 is disposed not in the vicinity of the outer periphery of the joint but in the center of the joint. Thereby, the 1st stress adjustment material 2 is pulled by the thermal expansion of the 2nd stress adjustment material 3, and it can prevent that the 1st stress adjustment material 2 deform | transforms more than original thermal expansion.

  FIG. 15 is a cross-sectional view and plan view of the principal part of the semiconductor device of Example 11. The difference from FIG. 14 is that the protrusion 3a of the second stress adjusting material 3 is a screw, and the first stress adjusting material 2 and the second stress adjusting material 3 are connected by screw fastening. . Thereby, the assembly | attachment of the 1st stress adjusting material 2 and the 2nd stress adjusting material 3 can be simplified.

  FIG. 16 is a cross-sectional view and plan view of the main part of the semiconductor device of Example 12. A difference from FIG. 13 is that the protrusion 3 a of the second stress adjusting material 3 is arranged so as to overlap the semiconductor element 1. Thereby, the heat generated in the semiconductor element 1 can be efficiently released to the heat dissipation base 8 on the second stress adjusting material 3 side. In FIG. 16, the number of the holes of the first stress adjusting material 2 and the number of the protrusions of the second stress adjusting material 3 are four, but it is not necessary to be four. The shape of the holes and protrusions need not be cylindrical.

  FIG. 17 is a cross-sectional view and plan view of the principal part of the semiconductor device of Example 13. The difference from FIG. 15 is that the protrusion 3 a of the second stress adjusting material 3 overlaps with the semiconductor element 1 and only one protrusion 3 a is disposed at the center of the junction. Thereby, the heat generated in the semiconductor element 1 can be efficiently released to the heat dissipation base 8 on the second stress adjusting material 3 side, and the thermal stress generated at the end of the bonding material can be reduced.

  FIG. 18 is a fragmentary cross-sectional view of the semiconductor device of Example 14. The difference from FIG. 17 is that the protrusion 3 c of the second stress adjusting material 3 is a screw and does not penetrate the first stress adjusting material 2. Thereby, deterioration of the bonding material 5 between the semiconductor element 1 and the first stress adjusting material 2 near the center can be prevented.

  FIG. 19 is a cross-sectional view and plan view of the principal part of the semiconductor device of Example 15. The semiconductor device shown in FIG. 19 includes a second stress adjusting material 3, a first stress adjusting material 2, an insulating substrate 7 having a circuit formed of copper foil on both surfaces of the insulating material, a semiconductor element 1, and copper foil on both surfaces of the insulating material. The insulating substrate 7 on which the circuit is formed, the first stress adjusting material 2 and the second stress adjusting material 3 are laminated, and the heat conducting material 6 is interposed between the first stress adjusting material 2 and the second stress adjusting material 3. The other members are connected by a bonding material 5. In addition, the outer case of the module is not omitted. The difference from FIG. 13 is that insulating substrates 7 and stress adjusting materials 2 and 3 are arranged on both sides. This doubles the heat dissipation area, improving heat dissipation. In FIG. 19, the number of the holes of the first stress adjusting material 2 and the number of the protrusions of the second stress adjusting material 3 are two, but it is not necessary to be two. The shape of the holes and protrusions need not be cylindrical.

  According to the embodiment described above, even if the temperature of the semiconductor device rises and each member around the connection portion thermally expands, the difference in expansion amount between the semiconductor element and the plate having a linear expansion coefficient close to the semiconductor element. Is small, the thermal stress generated in the bonding material therebetween is small. Further, since the difference in expansion amount between the electrode and a plate having a linear expansion coefficient close to the electrode is small, the thermal stress generated in the substitute material for the impact is similarly reduced. In addition, the two inserted plates are mechanically connected to each other, and the protrusions inside the holes are thermally expanded to increase the contact surface pressure between them. The connection is stronger, and the deterioration of each connection portion due to repeated heat changes is reduced.

DESCRIPTION OF SYMBOLS 1 Semiconductor element 2 1st stress adjusting material 3 2nd stress adjusting material 3a Connection protrusion 4 Electrode 5 Bonding material 6 Thermal conductive material 7 Insulated substrates 7a and 7b having circuits formed on both surfaces 8 Heat dissipation base 9 Lead frame electrode

Claims (10)

A semiconductor element;
A first stress adjusting material connected to the semiconductor element via a bonding material and having a hole;
A second stress adjusting material provided with a protrusion press-fitted into the hole;
A semiconductor device comprising: a heat conductive material filled between the first stress adjusting material and the second stress adjusting material. A semiconductor element;
A lead frame electrode connected to the semiconductor element via a bonding material;
A first stress adjusting material connected to the semiconductor element via a bonding material and having a hole;
A second stress adjusting material provided with a protrusion press-fitted into the hole;
An insulating substrate connected to the second stress adjusting material via a bonding material;
A heat dissipation base connected to the insulating substrate via a bonding material;
A semiconductor device comprising: a heat conductive material filled between the first stress adjusting material and the second stress adjusting material. The semiconductor device according to claim 1 or 2,
The semiconductor device according to claim 1, wherein a linear expansion coefficient of the first stress adjusting material is smaller than a linear expansion coefficient of the second stress adjusting material. The semiconductor device according to claim 3.
A semiconductor device, wherein the first stress adjusting material has a linear expansion coefficient of 10 ppm / ° C. or less. The semiconductor device according to claim 2,
The semiconductor device, wherein the second stress adjusting material and the heat dissipation base are made of the same material. The semiconductor device according to claim 1 or 2,
The hole is formed in a central portion of the first stress adjusting material,
The semiconductor device according to claim 1, wherein the protrusion is provided at a central portion of the second stress adjusting material. The semiconductor device according to claim 1 or 2,
The semiconductor device, wherein the hole and the protrusion are provided in a region overlapping with the semiconductor element. The semiconductor device according to claim 1 or 2,
The semiconductor device, wherein the hole and the protrusion have a screw structure. The semiconductor device according to claim 8,
The semiconductor device according to claim 1, wherein the hole does not penetrate the first stress adjusting material. A semiconductor element;
A first stress adjusting material connected to the semiconductor element via a bonding material and having a hole;
A second stress adjusting material provided with a protrusion press-fitted into the hole;
A heat conductive material filled between the first stress adjusting material and the second stress adjusting material;
A semiconductor device, wherein the first stress adjusting material, the heat conducting material, and the second stress adjusting material are symmetrically arranged on both sides of the semiconductor element with the semiconductor element as an axis.

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