Semiconductor device

A semiconductor device 1 includes a thermal radiation member 4; a first semiconductor chip 21 connected to the thermal radiation member 4; a second semiconductor chip 22 connected to the thermal radiation member 4; and sealing resin 93 sealing the first semiconductor chip 21 and the second semiconductor chip 22. The semiconductor device 1 comprises a first thermal diffusion member 31 connected to the thermal radiation member 4; a second thermal diffusion member 32 connected to the thermal radiation member 4; and a cooler 5 configured to cool the first thermal diffusion member 31 and the second thermal diffusion member 32. A space between the first thermal diffusion member 31 and the second thermal diffusion member 32 is positioned to oppose a space between the first semiconductor chip 21 and the second semiconductor chip 22 via the thermal radiation member 4.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2014-137615 filed on Jul. 3, 2014, the contents of which are hereby incorporated by reference into the present application.

TECHNICAL FIELD

The present application relates to a semiconductor device.

DESCRIPTION OF RELATED ART

A semiconductor device is disclosed in Japanese Patent Application Publication No. 2012-028520. The semiconductor device of Japanese Patent Application Publication No. 2012-028520 is provided with a plurality of semiconductor chips disposed to be spaced from each other, a graphite thermal diffusion plate fixed to the semiconductor chips, and a metal substrate fixed to the graphite thermal diffusion plate. The plurality of semiconductor chips is sealed with sealing resin.

In the semiconductor device of Japanese Patent Application Publication No. 2012-028520, the semiconductor chips generate heat by being energized. When the semiconductor chips repeatedly generate heat by the semiconductor device turning on and off, the sealing resin sealing the semiconductor chips expands and contracts, and the sealing resin may delaminate from the semiconductor chips. Further, in case of thermal treatment during manufacture of the semiconductor device, the sealing resin may contract and delaminate from the semiconductor chips.

BRIEF SUMMARY OF INVENTION

The present specification aims to present a semiconductor device capable of reducing delamination of the sealing resin. One aspect of the present disclosure provides a semiconductor device. The semiconductor device comprises a thermal radiation member made of metal and including a first surface and a second surface that is on an opposite side of the first surface; a first semiconductor chip connected to the first surface of the thermal radiation member; a second semiconductor chip spaced from the first semiconductor chip and connected to the first surface of the thermal radiation member; and sealing resin sealing the first semiconductor chip, the second semiconductor chip, and the first surface of the thermal radiation member between the first semiconductor chip and the second semiconductor chip. The semiconductor device further comprises a first thermal diffusion member made of carbon-based material and connected to the second surface of the thermal radiation member at a position opposed to the first semiconductor chip; a second thermal diffusion member made of carbon-based material and connected to the second surface of the thermal radiation member at a position opposed to the second semiconductor chip; and a cooler configured to cool the first thermal diffusion member and the second thermal diffusion member, and being disposed to face the second surface of the thermal radiation member. The first thermal diffusion member and the second thermal diffusion member are spaced from each other, and are disposed such that a space between the first thermal diffusion member and the second thermal diffusion member is positioned to oppose a space between the first semiconductor chip and the second semiconductor chip via the thermal radiation member.

According to the semiconductor device, when heat generated by the semiconductor chips is transmitted to the thermal diffusion members, thermal stress occurs in the thermal diffusion members. At this juncture, since the first thermal diffusion member and the second thermal diffusion member are spaced from each other, the first thermal diffusion member and the second thermal diffusion member can deform toward their space side, and thereby the thermal stress generated in the first thermal diffusion member and the second thermal diffusion member is reduced. Consequently, stress applied to the sealing resin from the first thermal diffusion member and the second thermal diffusion member is reduced and thereby the delamination of the sealing resin is suppressed.

Further, although high stress generally occurs readily between two semiconductor chips due to the sealing resin, in the semiconductor device described above, the first thermal diffusion member and the second thermal diffusion member are disposed such that the space between the first thermal diffusion member and the second thermal diffusion member is positioned to oppose the space between the first semiconductor chip and the second semiconductor chip. Therefore, the thermal radiation members disposed between the first semiconductor chip and the second semiconductor chip easily follow the expansion and contraction of the sealing resin. Consequently, it is possible to reduce the thermal stress of the sealing resin even between the first semiconductor chip and the second semiconductor chip, and the delamination of the sealing resin can be reduced.

DETAILED DESCRIPTION OF INVENTION

Embodiments will be described below with reference to the accompanying figures. In the description below, components that are the same in each component element will be described collectively, and duplicate description thereof may be omitted.

As shown inFIG. 1, a semiconductor device1of the present embodiment comprises a plurality of semiconductor chips2(a first semiconductor chip21and a second semiconductor chip22), and a plurality of thermal radiation members4(a first thermal radiation member41and a second thermal radiation member42). Further, the semiconductor device1comprises a plurality of thermal diffusion members3(first thermal diffusion members31and second thermal diffusion members32), and a plurality of coolers5(a first cooler51and a second cooler52).

For example, an IGBT (Insulated Gate Bipolar Transistor) or FWD (Free Wheeling Diode), etc. can be used as the semiconductor chips2(the first semiconductor chip21and the second semiconductor chip22). In the case where an IGBT and FWD are used, for example, the first semiconductor chip21is the IGBT, the second semiconductor chip22is the FWD, and the first semiconductor chip21and the second semiconductor chip22can be arranged in a reverse conducting state. In the case where the semiconductor chips2are IGBTs, a gate region, emitter region, collector region, etc. (not shown) are formed within each of the semiconductor chips2. Further, in the case where the semiconductor chips2are FWDs, an anode region, a cathode region, etc. (not shown) are formed within each of the semiconductor chips2.

The plurality of semiconductor chips2(the first semiconductor chip21and the second semiconductor chip22) is disposed between the plurality of thermal radiation members4(the first thermal radiation member41and the second thermal radiation member42). The first semiconductor chip21and the second semiconductor chip22are disposed abreast. The first semiconductor chip21and the second semiconductor chip22are disposed apart from one another and adjacent in a left and right direction. The first semiconductor chip21is spaced from the second semiconductor chip22. The second semiconductor chip22is spaced from the first semiconductor chip21. In the example shown inFIG. 1, the first semiconductor chip21is disposed at the left side, and the second semiconductor chip22is disposed at the right side. A space portion25is formed between the first semiconductor chip21and the second semiconductor chip22. The first semiconductor chip21and the second semiconductor chip22are connected respectively to surfaces40of the thermal radiation members4(the first thermal radiation member41and the second thermal radiation member42).

Metal plate or metal foil such as, for example, copper (Cu), aluminum (Al), etc. can be used as the thermal radiation members4(the first thermal radiation member41and the second thermal radiation member42). The thermal radiation members4have thermal conductivity and electrical conductivity. The first thermal radiation member41and the second thermal radiation member42are disposed abreast with a space therebetween. The first thermal radiation member41and the second thermal radiation member42are disposed apart from one another and adjacent in an above and below direction. In the example shown inFIG. 1, the first thermal radiation member41is disposed at a lower side, and the second thermal radiation member42is disposed at an upper side. The first thermal radiation member41is disposed below the plurality of semiconductor chips2, and the second thermal radiation member42is disposed above the plurality of semiconductor chips2. The first thermal radiation member41is fixed to a lower surface of the first semiconductor chip21and a lower surface of the second semiconductor chip22. The second thermal radiation member42is fixed to an upper surface of the first semiconductor chip21and an upper surface of the second semiconductor chip22.

The lower side first thermal radiation member41and each of the semiconductor chips2(the first semiconductor chip21and the second semiconductor chip22) are respectively joined by solder91. A spacer92is positioned between the upper side second thermal radiation member42and each of the semiconductor chips2(the first semiconductor chip21and the second semiconductor chip22). A block body of metal such as, for example, copper (Cu), aluminum (Al), etc. can be used as the spacers92. The spacers92and the semiconductor chips2(the first semiconductor chip21and the second semiconductor chip22) are each joined by the solder91. The upper side second thermal radiation member42and the spacers92are each joined by the solder91.

Sealing resin93is filled between the first thermal radiation member41and the second thermal radiation member42. The sealing resin93has an insulating property. Epoxy resin, for example, can be used as the material of the sealing resin93. The sealing resin93seals the semiconductor chips2(the first semiconductor chip21and the second semiconductor chip22). Further, the sealing resin93seals an upper surface of the first thermal radiation member41and a lower surface of the second thermal radiation member42. That is, the sealing resin93seals the surfaces40of the thermal radiation members4between the first semiconductor chip21and the second semiconductor chip22. The sealing resin93is filled in the space portion25between the first semiconductor chip21and the second semiconductor chip22. Surfaces of the first thermal radiation member41and the second thermal radiation member42positioned in the space portion25are also sealed by the sealing resin93.

The first thermal radiation member41is connected to the first cooler51via the thermal diffusion members3and an insulating member56. The second thermal radiation member42is connected to the second cooler52via the thermal diffusion members3and the insulating member56. The thermal diffusion members3will be described in detail later.

The insulating member56is disposed at a surface of a housing53of each cooler5. Each insulating member56is disposed between the corresponding cooler5and thermal diffusion members3(the corresponding first thermal diffusion member31and second thermal diffusion member32). The insulating members56are formed from a resin having an insulating property. The insulating members56insulate the coolers5and the thermal diffusion members3.

Each cooler5is fixed to a surface of the corresponding insulating member56positioned at an opposing side to the thermal diffusion members3. The cooler5is fixed to the thermal diffusion members3via the insulating member56. The cooler5cools the first thermal diffusion member31and the second thermal diffusion member32by using flowing coolant.

As shown inFIG. 2, each cooler5comprises the housing53, and a plurality of partition walls54disposed within the housing53. The second cooler52has the same configuration as the first cooler51. The housing53surrounds the plurality of partition walls54. The plurality of partition walls54is disposed abreast spaced from each other. The plurality of partition walls54extend in parallel. A passage55is formed between the partition wall54and the partition wall54. The plurality of passages55is formed abreast spaced from each other. The plurality of passages55extends in parallel. The passages55extend along the direction in which the first semiconductor chip21and the second semiconductor chip22are arranged. A liquid coolant such as water, for example, flows through the interior of the housing53. The coolant flows through the passages55along the partition walls54. As shown by the arrow L inFIG. 2, the coolant flows from the side where the first semiconductor chip21is positioned toward the side where the second semiconductor chip22is positioned. The first semiconductor chip21is positioned at an upstream side in the flowing direction L of the coolant within the cooler5, and the second semiconductor chip22is positioned at a downstream side.

As shown inFIG. 3andFIG. 4, the slant members10(the first slant member101, the second slant member102, the third slant member103, the fourth slant member104) comprise a plurality of sheet members71. The plurality of sheet members71is stacked. Each slant member10is formed by the plurality of sheet members71being stacked. The sheet members71are formed from carbon-based material. Thus, the slant members10and the thermal diffusion members3include carbon-based material. For example, graphite, graphene, fullerenes, carbon nanotubes, etc. can be used as the carbon-based material. In the present embodiment, graphite is used as the carbon-based material. A surface of each slant member10is covered by a thin film73. The thin film73covers the entire surface of the slant member10. The thin film73is formed from metal. In the present embodiment, the thin film73is formed from nickel.

Each slant member10comprises one end face61, an other end face62, side faces63, a rear face64and a front end portion65. As shown inFIG. 4, an angle θ1between the one end face61and the rear face64of the thermal diffusion member3is preferably 30° to 60°, and is more preferably 45°. Further, an angle θ2between the other end face62and the rear face64of the thermal diffusion member3is preferably 120° to 150°, and is more preferably 135°. The one end face61and the other end face62are formed in a triangular shape.

Each slant member10is manufactured, for example, as follows. As shown inFIG. 5andFIG. 6, when manufacturing the thermal diffusion members3, the plurality of sheet members71are first stacked to form a stacked body72. From a top view, the sheet members71are generally rectangular. After the stacked body72has been formed, as shown inFIG. 7, an end portion of the stacked body72is cut obliquely with respect to the surface of the sheet members71. The slant member10is formed when the stacked body72is cut, as shown inFIG. 8. Thus, the thermal diffusion members3made of carbon-based material can be manufactured.

The sheet members71have anisotropic thermal conductivity. The thermal conductivity of the sheet members71is dependent on the orientation of the crystals of the carbon-based material. The thermal conductivity of the sheet members71is low in the stacking direction of the plurality of sheet members71(w direction ofFIG. 4toFIG. 8). In directions orthogonal to the stacking direction of the plurality of sheet members71(u direction and v direction ofFIG. 4toFIG. 8), the thermal conductivity of the sheet members71is higher than the thermal conductivity of the sheet members71in the stacking direction (w direction). That is, the thermal conductivity of the sheet members71is low in a thickness direction of the sheet members71, and the thermal conductivity of the sheet members71in a surface direction (direction along the surface) of the sheet members71is higher than the thermal conductivity in the thickness direction. The w direction ofFIG. 4toFIG. 8corresponds to a low thermal conductivity direction, the u direction corresponds to a first high thermal conductivity direction, and the v direction corresponds to a second high thermal conductivity direction. The low thermal conductivity direction (w direction), the first high thermal conductivity direction (u direction), and the second high thermal conductivity direction (v direction) are orthogonal to each other. In the case where graphite is used as the carbon-based material, thermal conductivity in the low thermal conductivity direction (w direction) ofFIG. 4toFIG. 8is approximately 7 W/mK, thermal conductivity in the first high thermal conductivity direction (u direction) is approximately 1700 W/mK, and thermal conductivity in the second high thermal conductivity direction (v direction) is approximately 1700 W/mK. Thus, the sheet members71have different thermal conductivity in three directions. Thermal conductivity in the high thermal conductivity direction of carbon-based material is higher than the thermal conductivity of metal. For example, the thermal conductivity of oxygen-free copper, which is a metal, is approximately 385 W/mK.

Because the sheet members71have anisotropic thermal conductivity, each slant member10also has anisotropic thermal conductivity. A direction from the front end portion65toward the rear face64of the slant member10(w direction ofFIG. 4) corresponds to the low thermal conductivity direction, and thermal conductivity in this direction is low. A direction from the one end face61toward the other end face62of the slant member10(u direction ofFIG. 4) corresponds to the first high thermal conductivity direction, and thermal conductivity in this direction is higher than the thermal conductivity of the low thermal conductivity direction (w direction). A direction from the one side face63toward the other side face63of the slant member10(v direction ofFIG. 4) corresponds to the second high thermal conductivity direction, and thermal conductivity in this direction is higher than the thermal conductivity of the low thermal conductivity direction (w direction).

As shown inFIG. 9, the plurality of slant members10is disposed abreast. The plurality of slant members10is disposed in a state facing different directions. The plurality of slant members10is disposed opposite each other. The plurality of slant members10is disposed in a state where the respective front end portions65are opposite each other. Each first thermal diffusion member31is formed by disposing the first slant member101and the second slant member102abreast and opposite each other in a state of facing different directions. Further, each second thermal diffusion member32is formed by disposing the third slant member103and the fourth slant member104abreast and opposite each other in a state of facing different directions.

As shown inFIG. 1andFIG. 9, the first thermal diffusion members31and the second thermal diffusion members32are disposed abreast spaced from each other. The first thermal diffusion members31and the second thermal diffusion members32are disposed adjacent along the left and right direction. In the example shown inFIG. 1, the plurality of first thermal diffusion members31is disposed at the left side, and the plurality of second thermal diffusion members32is disposed at the right side.

The first thermal diffusion members31are disposed to correspond to the first semiconductor chip21. The first thermal diffusion members31are disposed respectively above and below the first semiconductor chip21. The first thermal diffusion members31are disposed at a position opposing the first semiconductor chip21via the thermal radiation members4. The first thermal diffusion members31are disposed at a position overlapping with the first semiconductor chip21in the thickness direction of the first semiconductor chip21(z direction ofFIG. 1). The first thermal diffusion members31are disposed between the thermal radiation members4and the coolers5. The first thermal diffusion members31are connected to a back surface49of the corresponding thermal radiation members4(the first thermal radiation member41and the second thermal radiation member42). One end of the first thermal diffusion members31is connected to the corresponding thermal radiation member4at a position opposing the first semiconductor chip21. Another end of the first thermal diffusion members31is connected to the insulating member56. Similarly, the second thermal diffusion members32are disposed to correspond to the second semiconductor chip22. The second thermal diffusion members32are disposed respectively above and below the second semiconductor chip22. The second thermal diffusion members32are disposed at a position opposing the second semiconductor chip22via the thermal radiation members4. The second thermal diffusion members32are disposed at a position overlapping with the second semiconductor chip22in the thickness direction of the second semiconductor chip22(z direction ofFIG. 1). The second thermal diffusion members32are connected to the back surface49of the corresponding thermal radiation members4(the first thermal radiation member41and the second thermal radiation member42). One end of each of the second thermal diffusion members32is connected to the corresponding thermal radiation member4at a position opposing the second semiconductor chip22. Another end of each of the second thermal diffusion members32is connected to the insulating member56.

The plurality of slant members10configuring the thermal diffusion members3is disposed so as to expand obliquely from the thermal radiation members4toward the corresponding coolers5. The plurality of slant members10(the first slant members101, the second slant members102, the third slant members103, the fourth slant members104) each extends from the thermal radiation member4toward the cooler5in a slanted state relative to the thermal radiation member4. In the present embodiment, each slant member10is inclined at450with respect to the thermal radiation member4and the cooler5. Further, the first high thermal conductivity direction of each slant member10(u direction ofFIG. 4) is inclined at450with respect to the thermal radiation member4and the cooler5. The first high thermal conductivity direction extends in a direction from the thermal radiation member4toward the cooler5. That is, the first high thermal conductivity direction matches the longitudinal direction of each slant member10, and heat is transferred at high thermal conductivity from the thermal radiation member4toward the insulating member56. On the other hand, the second high thermal conductivity direction of each slant member10(v direction ofFIG. 4) extends parallel to the thermal radiation member4and the cooler5.

The first slant members101and the second slant members102configuring the first thermal diffusion members31are inclined in mutually different directions. In the examples shown inFIG. 1andFIG. 9, the first slant members101extend obliquely leftward from the thermal radiation members4toward the cooler5. On the other hand, the second slant members102extend obliquely rightward from the thermal radiation members4toward the coolers5. Each first slant member101is inclined so as to separate from the second slant member102with larger distance in the x direction in between them, from the thermal radiation member4side toward the cooler5side. Each second slant member102is inclined so as to separate from the first slant member101with larger distance in the x direction in between them, from the thermal radiation member4side toward the cooler5side. That is, the space between the first slant member101and the second slant member102is wider at the cooler5side than at the thermal radiation member4side.

The third slant members103and the fourth slant members104configuring the second thermal diffusion members32are inclined in mutually different directions. In the examples shown inFIG. 1andFIG. 9, the third slant members103extend obliquely left from the thermal radiation members4toward the coolers5. On the other hand, the fourth slant members104extend obliquely right from the thermal radiation members4toward the coolers5. Each third slant member103is inclined so as to separate from the fourth slant member104from the thermal radiation member4side toward the cooler5side. Each fourth slant member104is inclined so as to separate from the third slant member103from the thermal radiation member4side toward the cooler5side. That is, the space between the third slant member103and the fourth slant member104is wider at the cooler5side than at the thermal radiation member4side.

A space portion35is formed between the adjacent first thermal diffusion members31and second thermal diffusion members32. The spaces (the space portions35) between the first thermal diffusion members31and the second thermal diffusion members32are formed to correspond to the space (the space portion25) between the first semiconductor chip21and the second semiconductor chip22. The spaces (the space portions35) between the first thermal diffusion members31and the second thermal diffusion members32are disposed, via the thermal radiation members4, at a position opposing the space (the space portion25) between the first semiconductor chip21and the second semiconductor chip22. The space portions35of the thermal diffusion members3are formed above and below the space portion25of the semiconductor chips2. The space portions35of the thermal diffusion members3are formed at a position overlapping with the space portion25of the semiconductor chips2in the vertical direction (z direction ofFIG. 1).

As shown inFIG. 1, the thermal diffusion members3make contact with the thermal radiation members4. Further, the thermal diffusion members3make contact with the coolers5. Each of the slant members10configuring the thermal diffusion members3has a thermal radiation member4side end face, and a cooler5side end face. The one end face61of each slant member10corresponds to the thermal radiation member4side end face, and the other end face62corresponds to the cooler5side end face. One end face of each thermal diffusion member3, i.e., the one end face61of the slant member10, makes contact with the thermal radiation member4. One end face of each thermal diffusion member3, i.e., the one end face61of the slant member10, faces the thermal radiation member4side. The thermal diffusion members3are fixed to the thermal radiation members4by brazing or soldering. Another end face of each thermal diffusion member3, i.e., the other end face62of the slant member10, is connected to the cooler5via the insulating member56. The other end face of each thermal diffusion member3, i.e., the other end face62of the slant member10, faces the cooler5side.

As shown inFIG. 9andFIG. 10, the positions of the other end faces62of the first slant members101and the other end faces62of the second slant members102configuring the first thermal diffusion member31, and the positions of the other end faces62of the third slant members103and the other end faces62of the fourth slant members104configuring the second thermal diffusion member32, do not overlap each other in the flowing direction L of the coolant. That is, the position of the cooler5side end faces of the first thermal diffusion member31and the position of the cooler5side end faces of the second thermal diffusion member32are spaced apart in a direction intersecting with the flowing direction L of the coolant within the cooler5. The position of the cooler5side end faces of the first thermal diffusion member31and the position of the cooler5side end faces of the second thermal diffusion member32do not overlap each other in the flowing direction L of the coolant within the cooler5.

According to the semiconductor device1described above, when the semiconductor chips2(the first semiconductor chip21and the second semiconductor chip22) generate heat by being energized, the heat of the semiconductor chips2is transmitted to the thermal radiation members4(the first thermal radiation member41and the second thermal radiation member42) via the solder91and the spacers92. The heat transmitted to the thermal radiation members4is transmitted to the thermal diffusion members3(the first thermal diffusion members31and the second thermal diffusion members32) connected to the thermal radiation members4. On the other hand, the thermal diffusion members3(the first thermal diffusion members31and the second thermal diffusion members32) are cooled by the coolers5(the first cooler51and the second cooler52) in contact with the thermal diffusion members3. Thus, the heat generated by the semiconductor chips2is transmitted to the thermal diffusion members3, and the thermal diffusion members3are cooled by the coolers5. Thereby, the semiconductor chips2can be cooled.

When the heat generation of the semiconductor chips2is repeated, the expansion and contraction of the sealing resin93sealing the semiconductor chips2and the thermal radiation members4is repeated, and thereby the sealing resin93is subjected to stress in the direction of delamination from the semiconductor chips2or the thermal radiation members4. In particular, the expansion and contraction of the sealing resin93is likely to be greater in a portion between the first semiconductor chip21and the second semiconductor chip22, and the stress subjected on the sealing resin93increases.

The aforementioned semiconductor device1comprises the carbon-based material thermal diffusion members3(the first thermal diffusion members31and the second thermal diffusion members32) connected to the metal thermal radiation members4. In this semiconductor device1, the heat transmitted from the semiconductor chips2to the metal thermal radiation members4is transmitted from the thermal radiation members4to the carbon-based material thermal diffusion members3. Then, the thermal diffusion members3are cooled by the coolers5. At this juncture, since the thermal conductivity of carbon-based material is higher than the thermal conductivity of metal, the cooling effect can be enhanced by cooling the carbon-based material thermal diffusion members3. Further, disposing the thermal diffusion members3, which are of carbon-based material rather than metal, allows the thickness to be reduced of the thermal radiation members4, which are made of metal, and allows the rigidity of the thermal radiation members4to be reduced. Thus, even when the sealing resin93which seals the semiconductor chips2and the thermal radiation members4is subjected to repeated expansion and contraction, due to the rigidity of the thermal radiation members4having been reduced, consequently the thermal radiation members4can bend following the sealing resin93. Thereby, the stress applied to the sealing resin93can be reduced, and the delamination of the sealing resin93can be suppressed.

Further, when the heat generated by the semiconductor chips2is transmitted to the thermal diffusion members3(the first thermal diffusion members31and the second thermal diffusion members32), thermal stress occurs in the thermal diffusion members3. At this juncture, according to the semiconductor device1, the first thermal diffusion members31and the second thermal diffusion members32are disposed to be spaced from each other and, since the space portions35are formed, the influence of the thermal stress occurring in the thermal diffusion members3can be reduced by these space portions35. That is, since the thermal diffusion members3can bend to the space portion35side when stress occurs, the stress occurring in the thermal diffusion members3can be reduced. Thereby, it is possible to reduce the influence of the thermal stress of the thermal diffusion members3, exerted by these thermal diffusion members3on the thermal radiation members4to which they are connected, and it becomes easy for the thermal radiation members4to bend following the expansion and contraction of the sealing resin93. Thus, the delamination of the sealing resin93can be further reduced.

Further, the first thermal diffusion members31and the second thermal diffusion members32are positioned such that the space portions35between the first thermal diffusion members31and the second thermal diffusion members32are positioned opposing the space portion25between the first semiconductor chip21and the second semiconductor chip22, and consequently the thermal radiation members4between the first semiconductor chip21and the second semiconductor chip22are not constrained by the thermal diffusion members3. Thus, the thermal radiation members4, between the first semiconductor chip21and the second semiconductor chip22, easily bend following the expansion and contraction of the sealing resin93. By having the thermal radiation members4easily bend in the region between the first semiconductor chip21and the second semiconductor chip22, in which high stress readily occurs, stress can be reduced even in this region. Thus, the delamination of the sealing resin93can be suppressed.

Further, in the semiconductor device1, it is possible to reduce the thickness of the thermal radiation members4, and since the thickness can be made substantially constant, the manufacturing cost of the semiconductor device1can be reduced.

Further, since the plurality of slant members10configuring the thermal diffusion members3is disposed in the slanted state relative to the thermal radiation members4, the heat transmitted from the thermal radiation members4to the thermal diffusion members3can be diffused by the inclination of the slant members10. Thereby, the cooling effect can be enhanced. That is, the first slant members101and the second slant members102configuring the first thermal diffusion members31extend from the thermal radiation members4toward the coolers5in the slanted state such that the first slant members101and the second slant members102are further separated as they extend away from the thermal radiation member4side toward the opposing cooler5side. Thus, heat transmitted from the thermal radiation members4to the first thermal diffusion members31(the first slant members101and the second slant members102) is diffused, and the diffused heat is transmitted to the coolers5. Consequently, since the heat cools upon diffusion, the cooling effect can be enhanced. Further, similarly, the third slant members103and the fourth slant members104configuring the second thermal diffusion members32extend from the thermal radiation members4toward the coolers5in a slanted state such that the third slant members103and the fourth slant members104are further separated as they extend away from the thermal radiation member4side toward the opposing cooler5side. Thereby, the cooling effect can be enhanced.

Further, in the semiconductor device1, the position of the end faces of the first thermal diffusion members31at the cooler5side and the position of the end faces of the second thermal diffusion members32at the cooler5side are offset in the direction intersecting with the flowing direction L of the coolant within the cooler5. Thereby, since the position of the end faces making contact with the coolers5do not overlap each other in the flowing direction L of the coolant in the first thermal diffusion members31and the second thermal diffusion members32, the cooling effect can be enhanced. That is, when the position of the end faces of the first thermal diffusion members31at the cooler5side and the position of the end faces of the second thermal diffusion members32at the cooler5side overlap each other in the flowing direction L of the coolant, the second thermal diffusion members32are cooled by the coolant that has cooled the first thermal diffusion members31, and consequently it is difficult to enhance the cooling effect. However, when the position of the end faces of the first thermal diffusion members31at the cooler5side and the position of the end faces of the second thermal diffusion members32at the cooler5side do not overlap each other in the flowing direction L of the coolant, the first thermal diffusion members31and the second thermal diffusion members32can each be cooled by fresh coolant, and consequently the cooling effect can be enhanced.

A description of one embodiment has been given above. However, the specific embodiments are not limited to the above embodiment. In the following description, configurations similar to the configuration in the above description have the same reference numbers applied thereto, and a description thereof is omitted.

In the above embodiment, the configuration was that end faces of the thermal diffusion members3at the cooler5side make contact with the coolers5via the thin films73and the insulating members56, but the configuration is not limited to this. As shown inFIG. 11, a semiconductor device1of another embodiment may comprise metal members81disposed between the thermal diffusion members3and the coolers5. Metal block bodies of, for example, copper (Cu), aluminum (Al), etc. can be used as the metal members81. The metal members81are disposed respectively above the upper side thermal diffusion member3and below the lower side thermal diffusion member3. The metal members81make contact with the thermal diffusion members3and the coolers5. The end faces of the thermal diffusion members3(the first thermal diffusion members31and the second thermal diffusion members32) at the cooler5side (the other end faces62of the slant members10) make contact with the metal members81. The coolers5(the first cooler51and the second cooler52) make contact with the metal members81via the insulating members56. The metal members81function as a thermal mass. According to this configuration, by providing the metal members81, the heat can escape from the thermal diffusion members3to the metal members81. The heat is stored in the metal members81, and the coolers5cool these metal members81.

In the above embodiment, the configuration was that the metal members81are disposed between the thermal diffusion members3and the coolers5, but the configuration is not limited to this. In another embodiment, as shown inFIG. 12, a plurality of the metal members81may be positioned at lateral sides of the thermal radiation members4. The metal members81are disposed adjacent to the thermal radiation members4. The metal members81are disposed, respectively, to the left and right of the thermal radiation members4. The metal members81are sealed by the sealing resin93. The metal members81are disposed apart from the thermal radiation members4. Connecting members82are positioned between the metal members81and the thermal radiation members4. The connecting members82make contact with the metal members81and the thermal radiation members4. The metal members81and the thermal radiation members4make contact via the connecting members82. The connecting members82have thermal conductivity. Metal or carbon-based material can be used as the material of the connecting members82. According to this configuration, by providing the metal members81and the connecting members82, the heat can escape from the thermal radiation members4to the metal members81via the connecting members82. The heat is stored in the metal members81, which function as a thermal mass.

In the above embodiment, the connecting members82were positioned between the thermal radiation members4and the metal members81. However, the configuration is not limited to this and, as shown inFIG. 13, the connecting members82may be omitted. In the embodiment shown inFIG. 13, the metal members81are fixed to both end portions of the thermal radiation members4. The thermal radiation members4and the metal members81are formed integrally. One end portion181of each metal member81is sealed by the sealing resin93. An other end portion182of each metal member81makes contact with the cooler5via the insulating member56.

Further, in yet another embodiment, as shown inFIG. 14, the metal members81may be disposed between the thermal diffusion members3and the coolers5, and adjacent to the thermal radiation members4. The thermal radiation members4and the metal members81are formed integrally. The metal members81surround the thermal diffusion members3(the first thermal diffusion members31and the second thermal diffusion members32). Further, spaces183surrounded by the thermal radiation members4and the metal members81may be filled with liquid or metal powder. For example, the spaces183can be filled with water or liquid metal. Alternatively, the spaces183can be filled with copper (Cu) or aluminum (Al) powder.

Further, the number or disposition of the slant members10configuring the thermal diffusion members3is not restricted to the above embodiments. For example, as shown inFIG. 15, the first semiconductor chip21and the second semiconductor chip22can be brought closer to each other by reducing the number of slant members10configuring the thermal diffusion members3. In the example shown inFIG. 15, two of the slant members10are disposed for the first semiconductor chip21. The two slant members10for the first semiconductor chip21are positioned respectively above and below the first semiconductor chip21. InFIG. 15, only the slant members10below the first semiconductor chip21are shown. Similarly, two of the slant members10are disposed for the second semiconductor chip22. The two slant members10for the second semiconductor chip22are positioned respectively above and below the second semiconductor chip22. InFIG. 15, the two slant members10disposed below the second semiconductor chip22are shown. Further, in the example shown inFIG. 15, the slant members10configuring the first thermal diffusion member31and the slant members10configuring the second thermal diffusion member32are disposed so as to extend in a direction perpendicular to the flowing direction L of the coolant. According to this configuration, the distance between the first semiconductor chip21and the second semiconductor chip22can be reduced, and the plurality of semiconductor chips2can be arranged at high density.

Further, there is no particular restriction on the shape of the slant members10configuring the thermal diffusion members3. In the example shown inFIG. 15, the one end faces61and the other end faces62of the slant members10are formed in a square shape.

The coolers5of the above embodiments used flowing coolant, but are not limited to this configuration. Flowing coolant may not be used in the coolers5of another embodiment. The coolers5may be a heat sink or the like that does not use coolant.

In the above embodiment, the end faces of the thermal diffusion members3(the plurality of first thermal diffusion members31and the plurality of second thermal diffusion members32) at the cooler5side are fixed to the coolers5via the insulating members56, but are not limited to this configuration. In another embodiment, the other end faces62of the thermal diffusion members3may be in direct contact with the coolers5.

While specific examples of the present invention have been described above in detail, these examples are merely illustrative and place no limitation on the scope of the patent claims. The technology described in the patent claims also encompasses various changes and modifications to the specific examples described above. The technical elements explained in the present description or drawings provide technical utility either independently or through various combinations. The present invention is not limited to the combinations described at the time the claims are filed. Further, the purpose of the examples illustrated by the present description or drawings is to satisfy multiple objectives simultaneously, and satisfying any one of those objectives gives technical utility to the present invention.

Some features of the present disclosure will be listed below. It should be noted that each of the features listed below is independently useful.

1. The cooler may configured to cool the first thermal diffusion member and the second thermal diffusion member by using flowing coolant. A position of an end face of the first thermal diffusion member on a cooler side and a position of an end face of the second thermal diffusion member on the cooler side do not overlap each other in a flowing direction of the coolant.

According to this configuration, it is possible to suppress coolant heated by one thermal diffusion member flowing to a position at an end face of another thermal diffusion member. Consequently, the thermal diffusion members can be cooled efficiently by the coolant.

2. Each of the first thermal diffusion member and the second thermal diffusion member may comprise a slant member extending from the thermal radiation member to the cooler in a slanted state relative to the thermal radiation member.

3. The first thermal diffusion member may comprise a first slant member extending from the thermal radiation member to the cooler in a slanted state relative to the thermal radiation member; and a second slant member extending from the thermal radiation member to the cooler in a slanted state relative to the thermal radiation member, the second slant member being positioned farther away from the first slant member on a side closer to the cooler.

4. The semiconductor device may further comprise a metal member disposed between the first and second thermal diffusion members and the cooler.

5. The semiconductor device may further comprise a metal member disposed on a lateral side of the thermal radiation member.

6. The semiconductor device may further comprise a connecting member disposed between the thermal radiation member and the metal member, and connecting the thermal radiation member and the metal member.

7. The semiconductor device may further comprise a metal member surrounding the first thermal diffusion member and the second thermal diffusion member. Liquid, powder, or a combination thereof may be filled in a space surrounded by the metal member.

8. The slant members may extend in a direction orthogonal to a flowing direction of the coolant in the cooler.