JP2011009367A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device capable of achieving not only relaxation of thermal stress between a structure including a semiconductor element and its supporter, but also suitable suppression of thermal resistance although having a simpler structure.SOLUTION: The structure 300 including the semiconductor element 310 is constituted by integrally bonding a cooler 100 supporting the structure through a stress relaxation layer 200 relaxing stress generated between the structure 300 and the cooler 100. The stress relaxation layer 200 is composed as a coupled body and formed as a concavity/convexity engagement structure of many concavities and convexities, surfaces opposed to each other as coupling surfaces being so shaped as to relax movement orientation toward surfaces of the cooler 100 and structure 300.

Description

  The present invention relates to a semiconductor device, and in particular, is provided between a structure including a semiconductor element used for power conversion, various power control, and the like and a support that supports the structure, and stress between the structure and the support is reduced. The present invention relates to an improvement in a semiconductor device including a stress relaxation layer that relaxes.

  As such a semiconductor device, for example, in an electric vehicle or a hybrid vehicle, an inverter device that performs power conversion such as converting DC power supplied from a vehicle-mounted battery into three-phase AC for driving a motor is known. . In such a semiconductor device, a structure including a semiconductor element (power semiconductor element) is usually joined to a cooler in many cases. That is, when the semiconductor element is mounted on an insulating substrate or a heat sink by soldering or the like, the structure is joined and fixed to a cooler having a heat exchange function by brazing or soldering, etc. I try to alleviate the fever.

  However, when such a joining structure with a cooler is adopted, the linear expansion coefficient is generally different between the material used for the insulating substrate and the heat sink constituting the structure and the material used for the cooler. Stress due to such a difference in linear expansion coefficient is generated. And there exists a problem that a crack, curvature, etc. will arise in the joining layer which joins the said structure and a cooler due to such stress.

  Therefore, conventionally, in order to suppress the occurrence of cracks, warpage, and the like due to such a difference in linear expansion coefficient, for example, in the device described in Patent Document 1, the insulating substrate and the heat radiating plate that constitute the structure and its A stress relaxation member in which a plurality of through-holes or groove-shaped recesses are formed is interposed as a stress relaxation layer between the support and the cooler. Further, in the apparatus described in Patent Document 2, a plurality of micro fins movable in three axial directions are meshed between the insulating substrate and the heat radiating plate constituting the structure and the cooler as the support. The stress relaxation layer thus formed is interposed.

JP 2006-294699 A JP-A-6-5750

  As described above, according to the devices described in Patent Document 1 and Patent Document 2, the stress generated between the structure including the semiconductor element and the support such as a cooler that supports the semiconductor element is surely transmitted through the stress relaxation layer. Can be mitigated.

However, in the case of the apparatus described in Patent Document 1, in the above structure as the stress relaxation layer, the stress absorption space such as a plurality of through holes or groove-like recesses provided in the stress relaxation member is formed of an air layer. The air layer acts as a thermal resistance, and the heat exchange with the semiconductor element by the cooler is also hindered. Here, when the volume of the stress relaxation member constituting the stress relaxation layer is Val and the volume of the air layer is Vs, the ratio (occupancy) Ral occupied by the stress relaxation member in the stress relaxation layer is:

Ral = Val / Val (Val + Vs)

It becomes a relationship. The relationship between the occupation ratio Ral and the stress relaxation effect and the heat dissipation performance by the stress relaxation layer is a relationship in which the stress relaxation effect and the heat dissipation performance are opposite to each other as shown in FIG. Therefore, it is difficult to achieve both the stress relaxation effect and the heat dissipation performance.

  On the other hand, in the case of using a laminated body in which the plurality of microfins are meshed as the stress relaxation layer as in the device described in Patent Document 2, the direction in which stress relaxation is possible with one microfin is uniaxial. It is not only the direction, but the degree of freedom for stress relaxation is extremely low. For this reason, in order to relieve stress in a plurality of directions, it is necessary to laminate a plurality of the microfins, and the structure as the stress relieving layer must be complicated.

  The present invention has been made in view of such circumstances, and the object thereof is to reduce thermal stress generated between a structure including a semiconductor element and its support, while having a simpler structure, as well as heat. Another object of the present invention is to provide a semiconductor device capable of suitably suppressing resistance.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
According to the first aspect of the present invention, a structure including a semiconductor element is integrally joined to a support that supports the structure via a stress relaxation layer that relieves stress generated between the structure and the support. In the semiconductor device according to the present invention, the stress relaxation layer is formed of a combined body, and a plurality of recesses whose surfaces facing each other as a bonding surface have a shape that can relax movement directivity in the surface direction of the structure and the support. And it makes it a summary to be formed as the uneven | corrugated fitting structure of a convex part.

  As in the above configuration, the stress relaxation layer is formed from a plurality of concave and convex concave / convex fitting structures in which the opposing surfaces of the bonding surfaces have a shape that can relax the movement directivity to the structure and the support. If the concave and convex portions whose movement directivities are relaxed are deformed according to the stress generated between the structure and the support, or slippage between the concave and convex portions occurs. As a result, the stress inherent in the semiconductor device is absorbed. In addition, in the case of the same configuration, since the stress relaxation layer is configured as a combined body composed of an uneven fitting structure of a large number of concave portions and convex portions, the fitting area as the combined body is expanded, The thermal resistance can be suitably suppressed. Further, by constructing the stress relaxation layer as a combined body composed of a plurality of concave and convex concave / convex fitting structures whose movement directivity can be relaxed, the structural simplification of the stress relaxation layer can be achieved. It can also be seen.

The invention according to claim 2 is characterized in that, in the semiconductor device according to claim 1, the stress relaxation layer is made of a laminate having a surface formed as the concave-convex fitting structure as a laminated surface.
As in the above configuration, if the stress relaxation layer is configured as a laminate in which the surface formed as the uneven fitting structure is a laminate surface, the stress generated between the structure and the support by the laminate surface Is relaxed in such a manner as to be dispersed in the plane direction. Thereby, the stress relaxation effect by the stress relaxation layer is efficiently enhanced.

  According to a third aspect of the present invention, in the semiconductor device according to the second aspect, the convex portion is formed in a conical shape or a pyramid shape, and the concave portion is fitted to the conical or pyramidal convex portion. The main point is that it is formed in an inverted cone shape or an inverted pyramid shape.

As described above, if the convex portions constituting the stress relaxation layer have a conical shape or a pyramid shape, and the concave portions to be fitted into the convex portions are formed in an inverted conical shape or an inverted pyramid shape, these convex portions are formed. The fitting surface between the portion and the recess is inclined with respect to the thickness direction of the stress relaxation layer. For this reason, the degree of slippage between the convex portion and the concave portion is increased, and as a result, the stress relaxation capability as the stress relaxation layer is increased.

  According to a fourth aspect of the present invention, in the semiconductor device according to the second aspect, the convex portion is formed in a triangular prism shape having one column surface as a bottom, and the concave portion is fitted to the triangular prism-shaped convex portion. The gist is that it is formed in the shape of an inverted triangular prism.

  As in the above configuration, if a concave-convex fitting structure is formed by a convex portion having a triangular prism-shaped bottom surface and an inverted triangular prism-shaped concave portion fitted to the convex portion, these convex portions and Due to the deformation of the concave portion and the sliding effect between the inclined surface of the triangular prism-shaped convex portion and the inclined surface of the inverted triangular prism-shaped concave portion, the stress inherent in the semiconductor device is preferably alleviated.

  According to a fifth aspect of the present invention, in the semiconductor device according to any one of the second to fourth aspects, the concave portion and the convex portion are formed point-symmetrically with respect to the geometric center of the semiconductor element. This is the gist.

  In the semiconductor device described above, stress is generated from the outer edge of the structure or support toward the center of the semiconductor element serving as a heat source. In this regard, according to the above configuration, the recesses and the convex portions constituting the stress relaxation layer are formed point-symmetrically with respect to the geometric center of the semiconductor element, so that the semiconductor serving as a heat source from the outer edge of the structure or the support The movement directivity of the convex portion and the concave portion with respect to the stress generated toward the center of the element can be enhanced, and as a result, the stress relaxation effect as the stress relaxation layer can be accurately enhanced.

  According to a sixth aspect of the present invention, in the semiconductor device according to any one of the second to fourth aspects, the concave portions and the convex portions are formed radially with a geometric center of the semiconductor element as a base point. This is the gist.

  According to the above configuration, the concave portions and the convex portions constituting the stress relaxation layer are formed radially from the geometric center of the semiconductor element, so that the outer edge of the structure body or the support body extends from the outer edge of the semiconductor element to the center of the semiconductor element. Since the movement directivity of the convex portion and the concave portion is enhanced in a manner corresponding to the stress generated toward the surface, the stress relaxation effect as the stress relaxation layer can be accurately enhanced also in this case.

  According to a seventh aspect of the present invention, in the semiconductor device according to any one of the second to sixth aspects, the concave portion and the convex portion are formed in a circular shape having a geometric center of the semiconductor element as a midpoint. The gist of this is

  As described above, if the concave portions and the convex portions constituting the stress relaxation layer are formed in a circular shape centering on the geometric center of the semiconductor element, the movement directivity of the concave portions and the convex portions is the stress relaxation layer. In this case, the stress relaxation effect as the stress relaxation layer can be accurately enhanced.

  The invention according to claim 8 is the semiconductor device according to any one of claims 2 to 7, wherein the number of the concave portions and the convex portions is a corner portion of the stress relaxation layer from a geometric center of the semiconductor element. The gist is that it is formed in a manner that gradually increases over time.

In the semiconductor device described above, the stress at the corners of the structure or the support that increases the temperature fluctuation range is concentrated. In this regard, according to the above configuration, the number of the concave portions and the convex portions is gradually increased from the geometric center of the semiconductor element to the corner portion of the stress relaxation layer in a manner corresponding to the corner portion of the structure or support where the stress is concentrated. By being formed in such a manner, stress relaxation according to the degree of stress can be achieved, and stress inherent in the semiconductor device can be preferably relaxed.

The invention according to claim 9 is the semiconductor device according to any one of claims 1 to 8, wherein the support is a cooler for cooling the structure including the semiconductor element. .
The present invention is particularly effective when applied to a semiconductor device having a cooler for cooling a structure including a semiconductor element as a support, as described above, and the difference in linear expansion coefficient between the structure and the cooler. As a result, it is possible to suitably relieve the stress caused by the heat dissipation and improve the heat dissipation performance of the semiconductor device.

  The gist of the invention described in claim 10 is that, in the semiconductor device according to any one of claims 1 to 9, a plate material to be joined to form the stress relaxation layer is made of a metal plate material. .

  According to the above configuration, by configuring the stress relaxation layer with a metal plate, the thermal resistance as the stress relaxation layer can be suppressed when the stress existing in the semiconductor device is relaxed by the stress relaxation layer. As a result, the heat dissipation performance as a semiconductor device is further improved.

The invention according to claim 11 is the semiconductor device according to claim 10, wherein the metal plate is made of aluminum or copper.
If the plate material is made of aluminum as in the above configuration, the rigidity of the aluminum is low, so that the concave portion and the convex portion are easily deformed when the stress is absorbed by the stress relaxation layer. Thereby, the stress relaxation effect of these recessed parts and convex parts comes to be improved. Further, as described above, if the plate material is made of copper, the thermal conductivity of copper is high. Therefore, the stress relaxation layer relieves the stress inherent in the semiconductor device. The thermal resistance can be more suitably suppressed.

Sectional drawing which shows the cross-section of the semiconductor device concerning 1st Embodiment of this invention. The disassembled perspective view which shows typically the structure of the stress relaxation layer of the semiconductor device of the embodiment. The top view and sectional drawing which show the planar structure of the stress relaxation layer of the semiconductor device of the embodiment with the expanded sectional structure. The disassembled perspective view which shows typically the structure of the stress relaxation layer which comprises the semiconductor device concerning 2nd Embodiment of the semiconductor device concerning this invention. The top view and sectional drawing which show the planar structure of the stress relaxation layer of the semiconductor device of the embodiment with the expanded sectional structure. The disassembled perspective view which shows typically the structure of the stress relaxation layer which comprises the semiconductor device concerning 3rd Embodiment of this invention. The top view and sectional drawing which show the planar structure of the stress relaxation layer of the semiconductor device of the embodiment with the expanded sectional structure. The disassembled perspective view which shows typically the structure of the stress relaxation layer which comprises the semiconductor device concerning 4th Embodiment of this invention. The top view and sectional drawing which show the planar structure of the stress relaxation layer of the semiconductor device of the embodiment with the expanded sectional structure. The disassembled perspective view which shows typically the structure of the stress relaxation layer which comprises the semiconductor device concerning 5th Embodiment of this invention. The top view and sectional drawing which show the planar structure of the stress relaxation layer of the semiconductor device of the embodiment with the expanded sectional structure. The disassembled perspective view which shows typically the structure of the stress relaxation layer which comprises the semiconductor device concerning 6th Embodiment of the semiconductor device concerning this invention. The top view and sectional drawing which show the planar structure of the stress relaxation layer of the semiconductor device of the embodiment with the expanded sectional structure. The planar view and sectional drawing which show the planar structure of the stress relaxation layer which comprises the semiconductor device concerning other embodiment of this invention with the sectional structure about other embodiment. The figure which shows the relationship between the stress relaxation effect of the stress relaxation layer which comprises the conventional semiconductor device, and heat dissipation performance.

(First embodiment)
FIG. 1 shows a schematic cross-sectional structure of a semiconductor device according to this embodiment. As shown in FIG. 1, this semiconductor device has a structure 300 mounted on a cooler 100 as a support via a stress relaxation layer 200.

  Here, the cooler 100 is intended to cool the heat generated by the operation of the semiconductor element 310 constituting the structure 300 by heat exchange. In the present embodiment, the cooler 100 is made of, for example, aluminum. A water-cooled cooler consisting of

  The structure 300 supported by the cooler 100 includes a semiconductor element 310 and an insulating substrate 320 on which the semiconductor element 310 is mounted. Of these, the semiconductor element 310 is a power semiconductor element that generates high-temperature heat during operation of, for example, an IGBT (insulated gate bipolar transistor), and the insulating substrate 320 is made of DBA (direct brazing aluminum). The aluminum plates 322 and 323 are bonded and fixed to both surfaces of the ceramic substrate 321 by brazing or the like. The aluminum plate 323 is surface-treated so that the wettability of the solder 311 can be obtained, and the semiconductor element 310 is mounted on the upper surface by soldering.

  Further, the stress relaxation layer 200 interposed between the structural body 300 and the cooler 100 is a portion that relaxes and absorbs thermal stress caused by the difference in linear expansion coefficient between the structural body 300 and the cooler 100. Yes, it is integrally joined to the structure 300 and the cooler 100 by brazing or other methods.

  As described above, the semiconductor device configured as described above has different linear expansion coefficients due to the difference in material between the structure 300 and the cooler 100. For this reason, when high temperature heat is generated in accordance with the operation of the semiconductor element 310, the cooler 100 becomes high temperature and thermally expands due to heat exchange between the semiconductor element 310 and the cooler 100, while the operation of the semiconductor element 310 is performed. When stopped, the cooler 100 gradually becomes low temperature and heat shrinks. And, in the case of such thermal expansion or contraction of the cooler 100, stress is inherent due to the difference in the linear expansion coefficient between the cooler 100 and the insulating substrate 320 bonded to the cooler 100, There is a risk of warping or cracking in the cooler 100 or the insulating substrate 320.

  Therefore, in the present embodiment, the stress relaxation layer 200 is interposed between the cooler 100 and the structure 300 in order to relieve the stress that causes warping and cracks in the cooler 100 and the insulating substrate 320. Yes. FIG. 2 schematically shows an exploded perspective structure of the stress relaxation layer 200 employed in the present embodiment.

As shown in FIG. 2, the stress relaxation layer 200 is configured as a combined body in which, for example, an aluminum lower plate 210 and an upper plate 220 are combined. Here, this combined body is a laminated body formed by laminating the lower plate 210 and the upper plate 220. In the lower plate 210 constituting such a combined body (laminated body), the movement directivity in the surface direction of the cooler 100 and the structure 300 can be relaxed on the surface facing the upper plate 220, and in particular, the non-directional property is set. A plurality of conical convex portions 211 having a shape are formed in a point-symmetric and matrix shape with a center line O corresponding to the geometric center of the semiconductor element 310 as a base point. In addition, the upper plate 220 has a shape in which the movement directivity in the surface direction of the cooler 100 and the structure 300 is omnidirectional on the surface facing the lower plate 210, and the convex portion 211 is fitted into the upper plate 220. A plurality of inverted conical recesses 221 are formed in a point-symmetrical and matrix manner with a center line O corresponding to the geometric center of the semiconductor element 310 as a base point. As a result, the lower plate 210 and the upper plate 220 form an uneven fitting structure in which the coupling surfaces (lamination surfaces) face each other. In addition, the number of these convex parts 211 and the recessed parts 221 is proportional to the stress relaxation capability of the stress relaxation layer 200, and these convex parts 211 and recessed parts 221 shall be formed as much as possible in manufacture.

  3 is formed on the upper plate 220 and the convex portion 211 formed on the lower plate 210 so as to show the enlarged cross-sectional structures along the AA line and the BB line along with the plan view. When the recesses 221 are fitted to each other, the stress relaxation layer 200 is formed as a laminate having the surface formed as the uneven fitting structure as a laminate surface. In the present embodiment, the stress relaxation layer 200 is formed by screwing the four corners of the lower plate 210 and the upper plate 220 with screws SC in order to maintain the mitigation of movement directivity with respect to the convex portions 211 and the concave portions 221. Fastening between the lower plate 210 and the upper plate 220 constituting the same is intended.

Next, the operation of the stress relaxation layer 200 by the semiconductor device of the present embodiment will be described.
In other words, if stress is generated on the cooler 100 or the structure 300, the movement directivity of the convex portion 211 and the concave portion 221 is omnidirectional, so that the convex portion 211 and the concave portion 221 are stressed. While it deform | transforms in the aspect which responds, slip comes to arise between the convex part 211 and the recessed part 221. FIG. Thus, the stress generated on the cooler 100 and the structure 300 is relaxed in such a manner that the stress is gradually dispersed.

As described above, according to the semiconductor device of this embodiment, the effects listed below can be obtained.
(1) The stress relaxation layer 200 interposed between the cooler 100 and the structure 300 can be moved from the conical convex portion 211 and the inverted conical concave portion 221 that can reduce the movement directivity, and are particularly omnidirectional. It decided to comprise as a conjugate | bonded_body provided with the uneven | corrugated fitting structure which becomes. As a result, the stress inherent in the semiconductor device is relaxed through deformation according to the stress of the convex portion 211 and the concave portion 221 and slipping between the convex portion 211 and the concave portion 221.

  (2) The stress relaxation layer 200 is configured as an uneven fitting structure of a large number of convex portions 211 and concave portions 221. Thereby, the fitting area as a combined body comes to be expanded, and the suitable suppression can also be aimed at also about the thermal resistance as the stress relaxation layer 200. FIG.

  (3) The stress relaxation layer 200 is constituted by a pair of upper and lower lower plates 210 and 220. As a result, the structure of the stress relaxation layer 200 can be simplified.

  (4) A surface formed as a fitting structure by the convex portion 211 and the concave portion 221 is a laminated surface of the lower plate 210 and the upper plate 220. Thereby, the stress relaxation effect with respect to the surface direction by the stress relaxation layer 200 is enhanced.

(5) The stress relaxation layer 200 is made of aluminum. Thereby, the movement directivity of the lower plate 210 and the upper plate 220 is relaxed, and as a result, the stress relaxation effect as the stress relaxation layer 200 is further enhanced.

  (6) The convex portion 211 is formed in a conical shape, and the concave portion 221 is formed in an inverted conical shape. As a result, the degree of slippage between the convex portions 211 and the concave portions 221 and the degree of mitigation of movement directivity can be increased, and as a result, the stress relaxation effect as the stress relaxation layer 200 can be enhanced.

(Second Embodiment)
Hereinafter, a second embodiment of the semiconductor device according to the present invention will be described with reference to FIGS. In the second embodiment, convex portions and concave portions formed on the lower plate 210 and the upper plate 220 are formed in a triangular prism shape and an inverted triangular prism shape with one column surface as the bottom, and other basic features. This configuration is the same as that of the first embodiment.

  4 and 5 show the structure of the stress relaxation layer 200 constituting the semiconductor device according to the second embodiment as a diagram corresponding to FIGS. 2 and 3 described above. In FIGS. 4 and 5, the same elements as those shown in FIGS. 2 and 3 are denoted by the same reference numerals, and redundant descriptions of these elements are omitted. .

  That is, as shown in FIG. 4, in the present embodiment, the lower plate 210 constituting the stress relaxation layer 200 has a convex portion having a shape that can relax the movement directivity, that is, a triangular prism-shaped convex portion having a bottom surface of one column. A portion 212 is formed. Further, the upper plate 220 coupled to the lower plate 210 has a shape in which the convex portion 212 is fitted, and a concave portion having a shape that can relieve movement directivity, that is, an inverted triangular prism shape having one column surface as a bottom. A recess 222 is formed. In the present embodiment, in consideration of the stress generated on the cooler 100 and the structure 300 transitioning from the four corners toward the center of the semiconductor element 310, the convex portions 212 and the concave portions 222 are formed. Are formed radially with a center line O corresponding to the geometric center of the semiconductor element 310 as a base point.

  And as shown in FIG. 5, the convex part 212 formed in the lower board 210 and the concave part 222 formed in the upper board 220 are mutually fitted, and the surface formed as the said uneven fitting structure is formed. A stress relaxation layer 200 is formed as a laminate that is a laminate surface.

  If stress is generated in the cooler 100 and the structure 300 due to the presence of the stress relaxation layer 200, the triangular prism-shaped convex portion 212 and the inverted triangular prism-shaped concave portion 222 whose movement directivity is relaxed are stressed. And a slip occurs between the convex portion 212 and the concave portion 222. In the present embodiment, the convex portions 212 and the concave portions 222 are formed radially with the center line O corresponding to the geometric center of the semiconductor element 310 as a base point, so that the four corners and peripheral edges of the cooler 100 and the structural body 300 are formed. The protrusion 212 and the recess 222 are deformed or slipped in a manner corresponding to the distribution of stress that changes toward the center line O starting from the portion. Thus, the stress generated on the cooler 100 and the structure 300 is relaxed in such a manner that the stress is gradually dispersed.

  As described above, according to the semiconductor device according to the present embodiment, the effects according to the effects (1) to (5) according to the first embodiment are obtained, and the effect (6) is obtained. Instead, the following effects can be obtained.

  (7) The convex portion 212 is formed in a triangular prism shape with one column surface as the bottom, and the concave portion 222 into which the convex portion 212 is fitted is formed in an inverted triangular prism shape. As a result, the lower plate 210 and the upper plate 220 are coupled by the fitting of the inclined surfaces of the convex portion 212 and the concave portion 222, so that the sliding effect between the convex portion 212 and the concave portion 222 is reduced. As a result, the stress relaxation effect as the stress relaxation layer 200 is enhanced.

  (8) The convex portions 212 and the concave portions 222 are formed radially with the center line O as a base point. As a result, the movement directivity of the convex portions 212 and the concave portions 222 is relaxed in a manner corresponding to the transition of the stress generated on the cooler 100 and the structural body 300. Stress relaxation ability is improved. Here, as the convex portions and concave portions formed on the lower plate 210 and the upper plate 220, instead of the conical convex portions 211 and the inverted conical concave portions 221 of the first embodiment, a triangular prism shape is used. Although the convex portion 212 and the inverted triangular prism-shaped concave portion 222 are adopted, the conical convex portion 211 and the inverted conical concave portion 221 of the first embodiment are radiated from the center line O as a base point. Of course, the formation is also effective.

(Third embodiment)
Hereinafter, a third embodiment of the semiconductor device according to the present invention will be described with reference to FIGS. In the third embodiment, as in the previous second embodiment, the convex and concave portions formed on the lower plate 210 and the upper plate 220 are triangular prisms and inverted triangular prisms with one column surface as the bottom. The other basic configuration is the same as that of the first embodiment.

  FIGS. 6 and 7 show the configuration of the stress relaxation layer 200 constituting the semiconductor device according to the third embodiment as a diagram corresponding to FIGS. 2 and 3 described above. In FIGS. 6 and 7, the same elements as those shown in FIGS. 2 and 3 are denoted by the same reference numerals, and redundant descriptions of these elements are omitted. .

  That is, as shown in FIG. 6, in the present embodiment, the lower plate 210 constituting the stress relaxation layer 200 has a convex portion having a shape capable of relaxing the movement directivity, that is, a triangular prism-shaped convex portion having a bottom surface of one column. A portion 213 is formed. In addition, the upper plate 220 coupled to the lower plate 210 has a shape in which the convex portion 213 is fitted, and a concave portion having a shape that can relieve the movement directivity, that is, an inverted triangular prism shape having one column surface as a bottom. The recess 223 is formed. In the present embodiment, the convex portion 213 and the concave portion 223 are considered in consideration that the stress generated on the cooler 100 and the structure 300 changes toward the center of the semiconductor element 310 with these four corners as base points. Is formed in a circular shape centering on a center line O corresponding to the geometric center of the semiconductor element 310.

  And as shown in FIG. 7, the surface formed as the said uneven | corrugated fitting structure by the convex part 213 formed in the lower board 210 and the recessed part 223 formed in the upper board 220 mutually fitting. A stress relaxation layer 200 is formed as a laminate that is a laminate surface.

  Assuming that stress is generated in the cooler 100 and the structure 300 due to the presence of the stress relaxation layer 200, the triangular prism-shaped convex portion 213 and the inverted triangular prism-shaped concave portion 223 whose movement directivity is relaxed are stressed. And a slip occurs between the convex portion 213 and the concave portion 223. In the present embodiment, the convex portions 213 and the concave portions 223 are formed in a circular shape with the center line O as the center, so that the degree of relaxation of the movement directivity of the convex portions 213 and the concave portions 223 is the center line O. And the convex portions 213 and the concave portions 223 are likely to be deformed and slipped. Thus, the stress generated on the cooler 100 and the structure 300 is relaxed in such a manner that the stress is gradually dispersed.

  As described above, according to the semiconductor device of the present embodiment, the effects (1) to (5) according to the first embodiment and the effect (7) according to the second embodiment. The following effect can be obtained instead of the effect (8) according to the second embodiment.

  (9) The convex portion 213 and the concave portion 223 are formed in a circular shape centered on the center line O. Thereby, the stress relaxation capability by these convex part 213 and the recessed part 223 comes to be improved with respect to all the directions of the stress relaxation layer 200. FIG. Here, as the convex portions and concave portions formed on the lower plate 210 and the upper plate 220, instead of the conical convex portions 211 and the inverted conical concave portions 221 of the first embodiment, a triangular prism shape is used. Although the convex portion 213 and the inverted triangular prism-shaped concave portion 223 are adopted, the conical convex portion 211 and the reverse conical concave portion 221 of the first embodiment are circular with the center line O as the center. Of course, it is also effective to form them.

(Fourth embodiment)
A fourth embodiment embodying the semiconductor device according to the present invention will be described below with reference to FIGS. In the fourth embodiment, the number of convex portions and concave portions formed on the lower plate 210 and the upper plate 220 is formed so as to gradually increase from the geometric center of the semiconductor element 310 to the corner portion of the stress relaxation layer 200. The other basic configuration is the same as that of the first embodiment.

  FIGS. 8 and 9 show the configuration of the stress relaxation layer 200 constituting the semiconductor device according to the second embodiment as a diagram corresponding to FIGS. 2 and 3 described above. In FIGS. 8 and 9, the same elements as those shown in FIGS. 2 and 3 are denoted by the same reference numerals, and redundant descriptions of these elements are omitted. .

  That is, as shown in FIG. 8, in the present embodiment, in view of the fact that the stress generated on the cooler 100 and the structure 300 changes toward the center of the semiconductor element 310 with the four corners as base points. On the plate 210, convex portions 214 are formed in such a manner that the number gradually increases from the center line O corresponding to the geometric center of the semiconductor element 310 to the four corners 210 </ b> A to 210 </ b> D of the lower plate 210. In addition, the upper plate 220 coupled to the lower plate 210 is formed with a concave portion 224 that fits the convex portion 214 in a manner that gradually increases from the center line O to the four corners 220A to 220D of the upper plate 220. Has been. In addition, as these convex part 214 and the recessed part 224, the thing of a cone shape and a reverse cone shape is each employ | adopted similarly to the previous 1st Embodiment.

  Then, as shown in FIG. 9, the convex portion 214 formed on the lower plate 210 and the concave portion 224 formed on the upper plate 220 are fitted to each other, so that the surface formed as the concave-convex fitting structure is formed. A stress relaxation layer 200 is formed as a laminate that is a laminate surface. As a result, as shown in the enlarged cross-sectional structure along the line AA in FIG. 9, the joint surface between the lower plate 210 and the upper plate 220 protrudes from the four corners 200A to 200D of the stress relaxation layer 200 toward the center. The concave-convex fitting structure in which the formation density of the portions 214 and the concave portions 224 is increased is formed.

  If stress is generated in the cooler 100 or the structure 300 due to the presence of the stress relaxation layer 200, the convex portions 214 and the concave portions 224 whose movement directivity is relaxed are deformed in a manner corresponding to the stress. At the same time, slip occurs between the convex portion 214 and the concave portion 224. In the present embodiment, the number of the convex portions 214 and the concave portions 224 is formed so as to gradually increase from the center line O to the four corners 200A to 200D of the stress relaxation layer 200 to the center line O. 100 and the stress generated from the four corners of the structure 300 are relaxed at the four corners 200A to 200D of the stress relaxation layer 200 in the initial stage and then gradually relaxed toward the center of the stress relaxation layer 200. . Thus, the stress relaxation layer 200 according to the present embodiment also relaxes the stress generated on the cooler 100 and the structure 300 in such a manner that the stress is gradually dispersed.

  As described above, according to the semiconductor device according to the present embodiment, effects similar to the effects (1) to (6) according to the first embodiment are obtained, and the following effects are further obtained. Can be obtained together.

  (10) The convex portions 214 and the concave portions 224 formed on the lower plate 210 and the upper plate 220 are formed in such a manner that they gradually increase from the center line O to the four corners 210A to 210D and 220A to 220D of the lower plate 210 and the upper plate 220. It was decided to. As a result, the stress generated from the four corners of the cooler 100 and the structure 300 can be preferably alleviated at the initial stage.

(Fifth embodiment)
Hereinafter, a fifth embodiment of the semiconductor device according to the present invention will be described with reference to FIGS. In the fifth embodiment, the convex portions and the concave portions formed on the lower plate 210 and the upper plate 220 are formed into a triangular prism shape having a conical convex portion 215 and an inverted conical concave portion 225 as one bottom. The convex portion 216 and the concave portion 226 having an inverted triangular prism shape with the bottom of one column surface are used, and other basic configurations are the same as those in the first embodiment.

  FIGS. 10 and 11 show the configuration of the stress relaxation layer 200 constituting the semiconductor device according to the fifth embodiment as a diagram corresponding to FIGS. 2 and 3 described above. In FIGS. 10 and 11, the same elements as those shown in FIGS. 2 and 3 are denoted by the same reference numerals, and redundant descriptions of these elements are omitted. .

  That is, as shown in FIG. 10, in the present embodiment, in view of the fact that the stress generated on the cooler 100 and the structural body 300 changes toward the center of the semiconductor element 310 with these four corners as base points. Conical convex portions 215 are formed at a high density at the four corners 210A to 210D of the plate 210, and triangular prism-shaped convex portions 216 with one column surface at the bottom are formed on the four sides between the four corners 210A to 210D. It will be formed. The upper plate 220 coupled to the lower plate 210 is formed with an inverted conical concave portion 225 fitted to the convex portion 215 at the four corners 220A to 220D. Further, on the four sides between the four corners 220 </ b> A to 220 </ b> D of the upper plate 220, an inverted triangular prism-shaped concave portion 226 is formed with the bottom of one column surface that is fitted to the convex portion 216.

  Then, as shown in FIG. 11, a conical convex portion 215 formed on the lower plate 210 and an inverted conical concave portion 225 formed on the upper plate 220 are fitted to each other and are also formed on the lower plate 210. The triangular prism-shaped convex portion 216 and the inverted triangular prism-shaped concave portion 226 formed on the upper plate 220 are fitted to each other, so that the surface formed as the concave-convex fitting structure serves as a laminated surface. The stress relaxation layer 200 is configured. As a result, as shown in FIG. 11 in an enlarged cross-sectional structure along the line B1-B1, on the outer edge side of the stress relaxation layer 200 of the joint surface between the lower plate 210 and the upper plate 220, A high-density concavo-convex fitting structure is formed at the four corners 200A to 200D, and a low-density concavo-convex fitting structure is formed between the four corners 200A to 200D. Further, as shown in FIG. 11 in which an enlarged cross-sectional structure along the line B2-B2 is shown, the concave-convex fitting structure is not formed on the inner side of the stress relaxation layer 200 in the joint surface between the lower plate 210 and the upper plate 220. It becomes.

  Assuming that stress is generated in the cooler 100 and the structure 300 due to the presence of the stress relaxation layer 200, first, conical protrusions formed at high density at the four corners 200A to 200D of the stress relaxation layer 200. The stress generated from the four corners of the cooler 100 and the structure 300 is relieved at the initial stage by the portion 215 and the inverted conical recess 225. Even in the vicinity of the stress relaxation layer 200, the stress generated on the cooler 100 and the structural body 300 is relaxed by the triangular prism-shaped convex portion 216 and the inverted triangular prism-shaped concave portion 226. Thus, the stress generated from the four corners of the cooler 100 and the structure 300 is gradually relaxed as it changes from 200A to 200D of the stress relaxation layer 200 to the center thereof.

  As described above, according to the semiconductor device of the present embodiment, the effects (1) to (6) according to the first embodiment and the (7) according to the second embodiment described above. The effect according to the effect is obtained, and the following effect is obtained.

  (11) The concave / convex fitting structure is formed by the conical convex portions 215 and the inverted conical concave portions 225 at the four corners 200A to 200D of the stress relaxation layer 200, and the triangular prism-shaped convex portions 216 around the stress relaxation layer 200 and The concave / convex fitting structure by the inverted triangular prism-shaped concave portion 226 is formed. Thereby, the stress relaxation ability with respect to the peripheral part of the cooler 100 or the structure 300 which becomes a starting point of the generation of stress and has a large influence is enhanced. Further, by adopting the minimum uneven fitting structure necessary for relieving the stress inherent in the semiconductor device in this way, the structure of the stress relieving layer 200 can be simplified.

  (12) The convex portions 215 and the concave portions 225 formed at the four corners 210A to 210D and 220A to 220D of the lower plate 210 and the upper plate 220 are formed with high density. Thereby, the stress relaxation ability with respect to the four corners of the cooler 100 and the structure 300 as a base point of stress generation can be enhanced, and the stress generated on the cooler 100 and the structure 300 can be relaxed at the initial stage. Will be able to.

(Sixth embodiment)
Hereinafter, a sixth embodiment of the semiconductor device according to the present invention will be described with reference to FIGS. In the sixth embodiment, the stress relaxation layer 200 is configured by a three-layer laminate, and other basic configurations are the same as those in the first embodiment.

  FIGS. 12 and 13 show the configuration of the stress relaxation layer 200 constituting the semiconductor device according to the sixth embodiment as a diagram corresponding to FIGS. 2 and 3 described above. In FIGS. 12 and 13, the same elements as those shown in FIGS. 2 and 3 are denoted by the same reference numerals, and redundant descriptions of these elements are omitted. .

  That is, as shown in FIG. 12, in the present embodiment, the stress relaxation layer 200 is configured as a laminate in which an intermediate plate 230 is interposed between the lower plate 210 and the upper plate 220. The intermediate plate 230 constituting such a laminated body has a shape in which the movement directivity in the surface direction of the cooler 100 and the structure 300 is relaxed on the surface facing the lower plate 210, and in particular has a non-directional shape. The inverted conical recesses 231 fitted with the projections 211 are formed in a matrix. Further, on the opposing surface of the upper plate 220 of the intermediate plate 230, the movement directivity in the surface direction of the cooler 100 and the structure 300 is relaxed, and in particular, a large number of conical shapes having a non-directional shape. Protrusions 232 are formed in a matrix. As a result, the coupling surface between the lower plate 210 and the middle plate 230 and the coupling surface between the middle plate 230 and the upper plate 220 are formed as a concave-convex fitting structure facing each other and as a laminated surface of the stress relaxation layer 200. ing.

  And as shown in FIG. 13, while the convex part 211 formed in the lower board 210 and the recessed part 231 formed in the middle board 230 are mutually fitted, the convex part 232 formed in the middle board 230, When the concave portion 221 formed on the upper plate 220 is fitted to each other, the stress relaxation layer 200 as a laminate having the surface formed as the concave-convex fitting structure as a laminated surface is configured.

  Thus, in the stress relaxation layer 200, the convex portions 211 and the concave portions 231 over the entire surface direction of the stress relaxation layer 200, as shown in FIG. 13 in an enlarged cross-sectional structure along the lines AA and BB. As a result, a concave / convex fitting structure is formed by the convex portion 232 and the concave portion 221.

  If stress is generated on the cooler 100 or the structure 300 due to the presence of the stress relaxation layer 200, the movement directivity of the convex portions 211 and the concave portions 231 and the convex portions 232 and the concave portions 221 is omnidirectional. As a result, the convex portions 211 and 232 and the concave portions 221 and 231 are deformed in a manner depending on the stress, and between the convex portions 211 and the concave portions 231, and between the convex portions 232 and the concave portions 221. Slip occurs between them. In addition, by forming a plurality of concave / convex fitting structures with the convex portions 211 and 232 and the concave portions 231 and 221, stress generated on the cooler 100 and the structure 300 is gradually reduced. It becomes like this. Thus, the stress generated on the cooler 100 and the structure 300 is relieved in such a manner that it is gradually dispersed by the stress relieving layer 200.

  As described above, according to the semiconductor device according to the present embodiment, effects similar to the effects (1) to (6) according to the first embodiment are obtained, and the following effects are further obtained. Can be obtained together.

  (13) The stress relaxation layer 200 is constituted by a three-layer laminate including the lower plate 210, the middle plate 230, and the upper plate 220. As a result, the stress generated on the cooler 100 and the structure 300 is gradually reduced by the concave-convex fitting structure on each coupling surface, and the stress relaxation effect by the stress relaxation layer 200 is further enhanced. It becomes like this.

(Other embodiments)
In addition, the said embodiment can also be implemented with the following forms.
In each of the above embodiments, the lower plate 210 and the upper plate 220 are coupled by the screw SC. In addition to this, when it is possible to ensure the mitigation of movement directivity between the convex portions 211 to 216 and 232 and the concave portions 221 to 226 and 231, for example, the lower plate 210 and the upper plate 220 are bonded with a bonding agent. You may make it combine. In addition, a lubricant such as silicon grease may be interposed on the joint surface between the lower plate 210 and the upper plate 220.

  In each of the above embodiments, the stress relaxation layer 200 is configured as a laminated body in which the surface formed as the uneven fitting structure is a laminated surface. Not limited to this, as shown in FIG. 14 as a diagram corresponding to FIG. 2 above, for example, as a layer coupled in the horizontal direction with the surface formed as the concave-convex fitting structure as a vertical tomographic plane, that is, in the horizontal direction The stress relaxation layer 200 may be configured as a combined body.

  In each of the above embodiments, the convex portions 211 to 216 are formed on the lower plate 210 and the concave portions 221 to 226 are formed on the upper plate 220. However, depending on the convex portions 211 to 216 and the concave portions 221 to 226, In forming the concave-convex fitting structure, the concave portions 221 to 226 may be formed on the lower plate 210 and the convex portions 211 to 216 may be formed on the upper plate 220. In the sixth embodiment, the concave portion 231 is formed on the lower surface of the intermediate plate 230 and the convex portion 232 is formed on the upper surface of the intermediate plate 230. However, the present invention is not limited to this, as long as the concave and convex fitting structure can be formed by the intermediate plate 230 and the lower plate 210 and the upper plate 220. The convex portion 232 is formed on the lower surface of the intermediate plate 230 and the intermediate plate 230 is formed. You may make it form the recessed part 231 in the upper surface of this. Similarly, recesses may be formed on the upper and lower surfaces of the intermediate plate 230, and the protrusions fitted into the recesses may be formed on the upper surface of the lower plate 210 and the lower surface of the upper plate 220. Similarly, convex portions may be formed on the upper and lower surfaces of the middle plate 230, and concave portions into which the convex portions are fitted may be formed on the upper surface of the lower plate 210 and the lower surface of the upper plate 220.

In the first embodiment, the convex portions 211 and the concave portions 221 are formed in a point-symmetrical matrix with the center line O corresponding to the geometric center of the semiconductor element 310 as a base point. The protrusions 211 and the recesses 221 are only required to be symmetric with respect to the center line O or only in a matrix shape, as long as the stress on the cooler 100 and the structure 300 can be relieved by the concave / convex fitting structure. You may make it do. In the second embodiment, the convex portions 212 and the concave portions 222 are formed radially from the center line O, and in the third embodiment, the convex portions 213 and the concave portions 223 are formed. Is formed in a circular shape centered on the center line O. Not limited to this, it is only necessary to be able to relieve stress inherent in the semiconductor device by a plurality of convex portions and concave portions whose movement directivity can be relaxed, and the convex portions and concave portions constituting the concave-convex fitting structure. The formation mode of is arbitrary.

  In each of the first, fourth, and sixth embodiments, the concave-convex fitting structure is configured by conical convex portions 211, 214, 232 and inverted conical concave portions 221, 224, 231. did. For example, the convex portions 211, 214, and 232 are formed in a pyramid shape or a triangular prism shape with one column surface as the bottom, and the concave portions 221, 224, and 231 are formed in an inverted pyramid shape or one column surface as the bottom. You may make it form in a reverse triangular prism shape. In addition, the fitting structure may be formed by columnar convex portions and concave portions. On the other hand, in each of the second and third embodiments, the concave-convex fitting structure includes the triangular prism-shaped convex portions 212 and 213 having one column surface as the bottom and the inverted triangular prism-shaped concave portion having the one column surface as the bottom. 222 and 223. For example, the convex portions 212 and 213 may be formed in a conical shape or a pyramid shape, and the concave portions 222 and 223 may be formed in an inverted conical shape or an inverted pyramid shape. On the other hand, in the fifth embodiment, the concave / convex fitting structure at the four corners 200A to 200D of the stress relaxation layer 200 is constituted by the conical convex portion 215 and the inverted conical concave portion 225, and the four sides of the stress relaxation layer 200 are provided. The concavo-convex fitting structure is composed of a triangular prism-shaped convex portion 216 and an inverted triangular prism-shaped concave portion 226 with one column surface as the bottom. Not only this but the uneven | corrugated fitting structure of four corners 200A-200D of the stress relaxation layer 200 is comprised by the triangular prism-shaped convex part and the reverse triangular prism-shaped recessed part which make one column surface the bottom, and four sides of the stress relaxation layer 200 are included. You may make it comprise an uneven | corrugated fitting structure by a cone-shaped convex part and a reverse cone-shaped recessed part. Further, the concave / convex fitting structure of the four corners and four sides of the stress relaxation layer 200 is formed only by a conical convex portion and an inverted conical concave portion, or by only a triangular prism-shaped convex portion and an inverted triangular prism-shaped concave portion having one column surface as a bottom. You may make it comprise.

  In short, it is sufficient if the movement directivity of the convex part and the concave part can be alleviated so that the stress generated on the cooler 100 and the structure 300 can be alleviated. The shapes of the convex portion and the concave portion are not limited to the shapes exemplified in those embodiments.

  In each of the above embodiments, the aluminum plate materials 210, 220, and 230 are used as the plate materials to be combined to form the stress relaxation layer 200. The plate material constituting the stress relaxation layer 200 may be made of copper. In this case, since the thermal conductivity of copper is high, the stress relaxation layer 200 is used to relax the stress inherent in the semiconductor device. As a result, the thermal resistance of the semiconductor device can be more suitably suppressed.

  In each of the above embodiments, a water-cooled cooler is used as the support, but the present invention is not limited to this, and an air-cooled cooler or a heat sink is used as the support for the structure 300. It may be.

  DESCRIPTION OF SYMBOLS 100 ... Cooler, 200 ... Stress relaxation layer, 200A-200D ... Four corners of stress relaxation layer, 210 ... Lower plate (plate material), 210A-210D ... Four corners of lower plate, 211-216 ... Projection, 220 ... Upper plate ( (Plate material), 220A to 220D ... four corners of upper plate, 221 to 226 ... concave portion, 230 ... middle plate (plate material), 231 ... concave portion, 232 ... convex portion, 300 ... structure, 310 ... semiconductor element, 311 ... solder, 320 ... Insulating substrate, 321 ... Ceramic substrate, 322 ... Aluminum plate, SC ... Screw.

Claims (11)

In a semiconductor device configured such that a structure including a semiconductor element is integrally bonded to a support that supports the structure via a stress relaxation layer that relieves stress generated between the structure and the support.
The stress relaxation layer is composed of a combined body, and a plurality of concave and convex irregularities whose surfaces facing each other as a bonding surface have a shape capable of relaxing movement directivity in the surface direction of the structure and the support. A semiconductor device formed as a fitting structure. The semiconductor device according to claim 1, wherein the stress relaxation layer is formed of a stacked body having a surface formed as the uneven fitting structure as a stacked surface. The said convex part is formed in cone shape or a pyramid shape, and the said recessed part is formed in the reverse cone shape or reverse pyramid shape fitted to the said cone shape or pyramid shape convex part. Semiconductor device. The semiconductor device according to claim 2, wherein the convex portion is formed in a triangular prism shape with one column surface as a bottom, and the concave portion is formed in an inverted triangular prism shape fitted to the triangular prism-shaped convex portion. The semiconductor device according to claim 2, wherein the concave portion and the convex portion are formed point-symmetrically with respect to a geometric center of the semiconductor element. The semiconductor device according to claim 2, wherein the concave portion and the convex portion are formed radially with a geometric center of the semiconductor element as a base point. The semiconductor device according to claim 2, wherein the concave portion and the convex portion are formed in a circular shape having a geometric center of the semiconductor element as a midpoint. The semiconductor device according to claim 2, wherein the number of the concave portions and the convex portions is formed so as to gradually increase from a geometric center of the semiconductor element to a corner portion of the stress relaxation layer. The semiconductor device according to claim 1, wherein the support is a cooler that cools a structure including the semiconductor element. The semiconductor device according to any one of claims 1 to 9, wherein a plate member bonded to form the stress relaxation layer is made of a metal plate member. The semiconductor device according to claim 10, wherein the metal plate material is made of aluminum or copper.