JP2015141934A - Cooling plate and semiconductor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling plate that enables large-power and high-speed switching over a long term without reducing heat radiation characteristics and reliability, and to provide a semiconductor module having a semiconductor element mounted on a metal layer of the cooling plate.SOLUTION: A cooling plate comprises: a flow channel member 1 in which a space surrounded by a barrier is a flow channel 1a; and a metal layer 2 provided on a principal surface 1s of the flow channel member 1. A semiconductor element is mounted via the metal layer 2. A thickness At of a barrier in at least a part of an end part region A where an end part of the metal layer 2 is located, is thicker than a thickness Bt of a barrier in a mounting region B where the semiconductor element is mounted.

Description

  The present invention relates to a cooling plate and a semiconductor module in which a semiconductor element is mounted on a metal layer of the cooling plate.

  In recent years, semiconductor devices have been used for high-power and high-speed switching, and when they generate heat and become high temperature in such applications, they may affect the switching function. Therefore, when mounting such a semiconductor element, a cooling plate in which a metal layer is formed on the main surface of a flow path member having a flow path capable of cooling the semiconductor element by flowing a fluid is used.

As such a cooling plate, for example, in Patent Document 1, a gap portion serving as a refrigerant flow path is formed in a lower portion of a circuit on which a semiconductor component is mounted, and a distance in the substrate thickness direction from the circuit to the gap portion is formed. t satisfies the condition of 0.5 mm ≦ t ≦ 5 mm, and the distance t and the width Y of the gap are Y
A cooling plate having a structure of ≦ 20 t has been proposed.

Japanese Patent Laid-Open No. 2002-329938

  As shown in FIG. 1 of Patent Document 1, when the end portion of the metal layer is located on the flow path on the main surface of the flow path member, there is a difference in the thermal expansion of the material itself between the semiconductor element and the flow path member. Yes, when the end of the metal layer that has received heat generated from the semiconductor element expands, the flow path member is cooled by the refrigerant, so that thermal stress is applied to the end region located at the end of the metal layer. It will hang. When this thermal stress is repeatedly applied, the end portion of the metal layer is peeled off, thereby deteriorating the heat dissipation characteristics and reducing the reliability of the cooling plate. In addition, when the thermal stress is repeatedly applied or the applied thermal stress is large, the above-described end region may be damaged, and there is a problem that the life is shortened including peeling of the end region. Therefore, in recent years, there is a need for a cooling plate that enables high-power and high-speed switching over a long period of time without degrading heat dissipation characteristics and reliability.

  The present invention has been devised to satisfy the above-described requirements, and provides a cooling plate that enables high-power and high-speed switching over a long period of time without deteriorating heat dissipation characteristics and reliability, and a metal layer on the cooling plate. A semiconductor module having a semiconductor element mounted thereon is provided.

  The cooling plate of the present invention includes a flow path member having a space surrounded by a partition wall as a flow path, and a metal layer on a main surface of the flow path member, and a semiconductor element is mounted via the metal layer. The thickness of the partition in at least a part of the end region where the end of the metal layer is located is thicker than the thickness of the partition in the mounting region where the semiconductor element is mounted. It is characterized by.

  The semiconductor module of the present invention is characterized in that a semiconductor element is mounted on the metal layer of the cooling plate of the present invention having the above-described configuration.

  The cooling plate of the present invention can be used over a long period of time without degrading heat dissipation characteristics and reliability even in high-power and high-speed switching.

  Further, according to the semiconductor module of the present invention, since the semiconductor element is mounted on the metal layer of the cooling plate of the present invention having the above-described configuration, further high power and high speed switching can be performed.

An example of the cooling plate of this embodiment is shown, (a) is a top view, and (b) is a cross-sectional view taken along line W-W 'in (a). The other example of the cooling plate of this embodiment is shown, (a) is a top view, (b) is sectional drawing in the X-X 'line | wire in (a). The other example of the cooling plate of this embodiment is shown, (a) is sectional drawing, (b) is sectional drawing in the Y-Y 'line | wire in (a). The other example of the cooling plate of this embodiment is shown, (a) is a top view, (b) is sectional drawing in the ZZ 'line in (a), (c) is in (b). It is a state figure at the time of thermal expansion. It is a top view which shows the other example of the cooling plate of this embodiment.

  Hereinafter, an example of this embodiment will be described with reference to the drawings. 1A and 1B show an example of a cooling plate according to the present embodiment, in which FIG. 1A is a top view and FIG. 1B is a cross-sectional view taken along line W-W ′ in FIG. In the following drawings, the same numbers are assigned to the same members.

As shown in FIG. 1, the cooling plate 10 according to the present embodiment includes a flow path member 1 and a metal layer 2 on the main surface 1 s of the flow path member 1, and is surrounded by partition walls constituting the flow path member 1. The space is a flow path 1a. Then, in the main surface 1s of the flow path member 1, when the region where the end of the metal layer 2 is located is the end region A and the region where the semiconductor element is mounted is the mounting region B, the cooling plate 10 of the present embodiment. The partition wall thickness At in at least a part of the end region A is larger than the partition wall thickness Bt in the mounting region B. Note that the end region A of the metal layer 2 means up to 20% of the distance from the end of the metal layer 2 to the center of the mounting region B of the semiconductor element.

  In the cooling plate 10 of the present embodiment, since the partition wall thickness At in at least a part of the end region A is thicker than the partition wall thickness Bt in the mounting region B, all the end portions of the metal layer 2 are mounted in the mounting region. When the thermal stress is repeatedly applied to the end region A due to switching at a high power and at a higher speed than when it is located on the partition wall having the same thickness as the partition wall thickness Bt in B, or when a large thermal stress is applied. Separation of the end of the metal layer 2 and damage to the partition walls can be suppressed. In the semiconductor element mounting region B, since the partition wall thickness Bt is thinner than the end region A, even if the semiconductor element generates heat due to high power and high speed switching, Since it can cool with the refrigerant | coolant which flows through 1a, the switching function which a semiconductor element has can fully be exhibited.

  Thus, the cooling plate 10 of the present embodiment can perform high power and high speed switching over a long period of time without degrading the heat dissipation characteristics and reliability. In addition, in FIG. 1, although the example where the thickness of the part along a flow path direction was thick was shown among the edge part area | regions A, about a part (front part and back part of a flow path direction) perpendicular | vertical to a flow path direction. In addition, the partition wall may be thicker than the mounting region B, and it is preferable to make the partition wall thicker than the mounting region B particularly in the front portion in the flow path direction.

  Next, FIGS. 2 and 3 show other examples of the cooling plate of the present embodiment, (a) is a cross-sectional view, (b) is an XX ′ line in each (a), YY It is sectional drawing in a line.

  As another form in which the partition wall thickness At in at least a part of the end region A is thicker than the partition wall thickness Bt in the mounting region B, a main part of the flow path member 1 is used as in the cooling plate 20 shown in FIG. In the surface 1s, the end region A is located in a region corresponding to the side wall of the partition wall, or the end region A is located in a region corresponding to the rib as in the cooling plate 30 shown in FIG. There may be.

  In such a configuration, the thickness At in the end region A has the same thickness as the height of the flow path member 1, and the thickness At in the end region A is thicker than the configuration in FIG. Therefore, even if thermal stress is repeatedly applied to the end region A due to high-power and high-speed switching, or even when large thermal stress is applied, peeling of the end of the metal layer 2 and damage to the partition walls are further suppressed. be able to.

  Next, FIG. 4 shows another example of the cooling plate of this embodiment, (a) is a top view, (b) is a sectional view taken along line ZZ ′ in (a), ( (c) is a state diagram at the time of thermal expansion in (b). In the following drawings, the display of the end region A is omitted.

  FIG. 4A shows a cooling plate 40 in which the metal layer 2 has an encircling slit 3 that encloses the mounting region B of the semiconductor element. Thus, when the metal layer 2 has the surrounding slit 3 surrounding the semiconductor element mounting region B, there is an expandable region when the metal layer 2 expands by receiving heat generated from the semiconductor element. For this reason, the thermal stress applied to the separation and the partition walls in the end region A can be relaxed.

  And when this go slit 3 is tapered, the state before receiving heat is the state shown in FIG. 4 (b), and when the state expanded by receiving heat is shown in FIG. 4 (c), Since the heat conduction efficiency is not lowered by the taper portions being attracted to each other at the time of thermal expansion, the cooling plate 40 having excellent heat radiation characteristics can be obtained while having an expandable region. As described above, it is preferable that the open portion of the surrounding slit 3 has a distance that can be easily caught during thermal expansion.

  FIG. 5 is a top view showing another example of the cooling plate of the present embodiment. FIG. 5 shows a cooling plate 50 that includes three surrounding slits 3, has a quadrangular shape when viewed from above, and has corner slits 4 that extend over the corners of the three surrounding slits 3.

  As described above, when a plurality of the surrounding slits 3 are provided, the shape in the top view is a polygonal shape, and the corner slits 4 extend over the corners of the plurality of surrounding slits 3, the corners of the surrounding slits 3 are formed at the time of thermal expansion. The applied thermal stress can be relaxed. The polygonal shape of the surrounding slit 3 in a top view includes, for example, a hexagonal shape and an octagonal shape other than the rectangular shape shown in FIG. In addition, the polygonal shape includes those in which the corners of the polygon are R-shaped.

Moreover, as the go slit 3 and the corner slit 4, for example, the thickness of the metal layer 2 is 250.
When it is ˜1500 μm, the width is 1-100 μm and the depth is 20-80% of the thickness of the metal layer 2.

Further, when a plurality of go-slits 3 are provided, the width of the open portion of the go-go slit 3 closer to the mounting region B is narrowed, and the open portion of the go-going slit 3 far from the mounting region B is made wider. The cooling plate 50 can withstand the further increase in heat generated from the semiconductor element.

  Further, in the cooling plate of the present embodiment, when the thickness of the metal layer 2 located in the end region A is thinner in the portion far from the mounting region B than in the portion close to the mounting region B, Since the thermal stress applied to the end region A corresponding to a distant portion is reduced, peeling of the end of the metal layer 2 and damage to the partition walls can be further suppressed. In particular, it is preferable that the thickness of the metal layer 2 located in the end region A gradually decreases from a portion close to the mounting region B toward a portion far from the mounting region B.

  The semiconductor module according to the present embodiment is not illustrated, but includes, for example, a semiconductor element mounted on the metal layer 2 of the cooling plates 10 to 50 illustrated in FIGS. Since the cooling plates 10 to 50 of the form are excellent in heat dissipation characteristics and reliability and have a long life, further high power and high speed switching can be performed. Here, the term “on the metal layer 2” includes a case where a semiconductor element is mounted on the metal layer 2 via an electrode pad.

  Next, an example in which the flow path member is made of ceramics and the metal layer is made of copper will be described as an example of the method for manufacturing the cooling module of the present embodiment.

  Here, the flow path member made of ceramic includes an aluminum oxide sintered body, a zirconium oxide sintered body, a composite sintered body of aluminum oxide and zirconium oxide, a silicon nitride sintered body, and an aluminum nitride sintered body. Etc. can be used.

  First, a slurry is prepared using raw material powder, a sintering aid, a binder, a solvent, and the like as the main components of each sintered body. Next, a green sheet is produced using this slurry by a doctor blade method. Then, the obtained green sheet is punched out with a mold or laser processed to obtain a plurality of sheets having a predetermined shape. Next, the obtained sheet is laminated and pressed to obtain a molded body which is a laminated body, and a flow path member can be obtained by firing at a firing temperature corresponding to the raw material powder using this. it can.

  In addition, as another method for producing a molded body, a clay may be produced using raw material powder, a sintering aid, a binder, a solvent, etc., and a molded body may be obtained by an extrusion molding method, or a slurry is spray-dried. Then, the granulated granule may be molded by a powder press method, or may be molded by a cold isostatic pressing (CIP) method and then cut into a predetermined shape. Further, the green sheet obtained by rolling the granules may be punched out with a mold or made into a predetermined shape by laser processing, and then laminated and pressed to obtain a molded body.

  Moreover, the molded body obtained by the extrusion molding method, the powder pressing method, and the CIP method does not need to be integrated, and for example, the upper wall, the lower wall, and the side wall may be individually manufactured. And the molded object produced separately can be made into a channel member if it joins at the time of baking using a bonding agent, or if it adheres with an adhesive after baking.

  Next, for the metal layer, for example, a paste is prepared using a conductive powder such as copper or silver, a glass powder, and an organic vehicle. And a metal layer can be formed by printing on the main surface of a flow-path member by a well-known screen printing method, and baking in the atmosphere match | combined with the electroconductive powder after drying. Further, as another method for producing the metal layer, a metal layer such as copper or silver may be formed by using an electrolytic plating method or an electroless plating method.

  By forming the metal layer by the manufacturing method as described above, the cooling plate of this embodiment can be obtained.

  Then, when the surrounding slit and the corner slit are provided, laser processing may be performed on the surface of the metal layer, and the sectional shape of the slit can be tapered by adjusting the output.

  In addition, in order to make the thickness of the metal layer located in the end region thinner in the portion far from the mounting region than in the portion close to the mounting region, for example, using a printing mask of a desired shape, Etching may be performed according to the components.

  And the semiconductor module of this embodiment can be obtained by mounting a semiconductor element on the metal layer 2 of the cooling plate obtained by the method mentioned above.

  Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made without departing from the scope of the present invention.

1: Channel member 1s: Main surface 1a Channel 2: Metal layer 3: Go slit 4: Corner slit A: End region (of metal layer) B: Mounting region of semiconductor element
10, 20, 30, 40, 50: Cooling plate

Claims (5)

A cooling plate in which a space surrounded by the partition wall is a flow path member, a metal layer on the main surface of the flow path member, and a semiconductor element is mounted via the metal layer, The cooling plate according to claim 1, wherein a thickness of the partition wall in at least a part of an end region where the end portion of the metal layer is located is larger than a thickness of the partition wall in a mounting region where the semiconductor element is mounted. The cooling plate according to claim 1, wherein the metal layer has an encircling slit that encloses a mounting region of the semiconductor element. 3. The cooling according to claim 2, wherein the metal layer includes a plurality of the surrounding slits, has a polygonal shape when viewed from above, and has corner slits extending over corners of the plurality of surrounding slits. plate. The thickness of the said metal layer located in the said edge part area | region is thinner in the part far from the said mounting area than the part close | similar to the said mounting area, The Claim 1 thru | or 3 characterized by the above-mentioned. The cooling plate as described. A semiconductor module comprising the semiconductor element mounted on the metal layer of the cooling plate according to any one of claims 1 to 4.

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