Semiconductor module

Abstract

To provide a semiconductor module capable of controlling an adhesive layer to a desired thickness.SOLUTION: The semiconductor module of the present invention is a semiconductor module in which a circuit bus bar provided with a semiconductor element and a cooler are bonded via an adhesive layer. Since the adhesive layer has the region A bonded to the cooler and the region B bonded to the circuit bus bar, the region A is divided in the in-plane direction of the adhesive layer to form a plurality of blocks, and the region B enters between the blocks of the region A and is bonded to the cooler, it is possible to provide a semiconductor module capable of controlling the adhesive layer to have a desired thickness.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semiconductor module. [Background technology]

[0002] Modules that incorporate semiconductor elements generate heat during operation, and this heat must be dissipated.

[0003] Patent document 1 describes that by laminating a non-thermoplastic resin adhesive and a thermoplastic resin adhesive on a metal plate connected to a cooler, an insulating adhesive layer has conductive metal wiring on which semiconductor elements are to be mounted on the thermoplastic resin adhesive surface, and then heating the insulating adhesive layer, the insulating adhesive layer adheres closely to the metal substrate and the conductive metal wiring layer, thereby improving the heat dissipation and heat resistance of the semiconductor module. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-43417 Summary of the Invention [Problem to be solved by the invention]

[0005] When heat from a semiconductor element is dissipated to a cooler via a circuit bus bar, an adhesive layer is used to insulate the circuit bus bar from the cooler, and therefore, to achieve both heat dissipation and insulation, it is necessary to control the thickness of the adhesive layer. In other words, if the adhesive layer is too thin, it will not satisfy the required insulation properties, and if it is too thick, it will hinder heat dissipation.

[0006] However, in the method described in Patent Document 1, the adhesive is applied to the entire surface of the metal plate, so if the application surface is large, even if the adhesive is leveled with a squeegee, the squeegee will bend, making it difficult to control the adhesive layer to the desired thickness.

[0007] The present invention has been made in consideration of the problems associated with the prior art, and its purpose is to provide a semiconductor module in which the adhesive layer can be controlled to a desired thickness. [Means for solving the problem]

[0008] As a result of extensive research into achieving the above-mentioned object, the inventors discovered that by forming the adhesive layer into a plurality of blocks divided in the in-plane direction and a portion covering the blocks, it is possible to prevent the squeegee from deflecting, thereby achieving the above-mentioned object, and thus completed the present invention.

[0009] That is, the semiconductor module of the present invention is a semiconductor module in which a circuit bus bar on which a semiconductor element is provided and a cooler are bonded via an adhesive layer. The adhesive layer has a region A bonded to the cooler and a region B bonded to the circuit bus bar, the region A is divided in the in-plane direction of the adhesive layer to form a plurality of blocks, The region B is inserted between the blocks of the region A and is bonded to the cooler. [Effects of the Invention]

[0010] According to the present invention, the adhesive layer is formed by dividing it into a plurality of blocks divided in the in-plane direction and a portion covering the blocks, thereby making it possible to provide a semiconductor module in which the adhesive layer can be controlled to a desired thickness even if the surface on which the adhesive layer is formed is wide. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing an example of the structure of a semiconductor module of the present invention. [Figure 2] 10A and 10B are diagrams illustrating a process for forming region A of the adhesive layer. [Figure 3] 10A and 10B are diagrams illustrating a process for forming a region B of the adhesive layer. DETAILED DESCRIPTION OF THE INVENTION

[0012] The semiconductor module of the present invention will now be described in detail. The semiconductor module 1 of the present invention includes a semiconductor element 2, a circuit bus bar 3, and a cooler 5 such as a housing in which a heat sink and a refrigerant flow path are formed.

[0013] The circuit bus bar 3 on which the semiconductor element 2 is mounted is adhered to the cooler via an adhesive layer 4 formed of an epoxy-based or silicone-based highly thermally conductive insulating adhesive, and the heat of the semiconductor element 2 is transferred to the cooler via the circuit bus bar 3 and the adhesive layer 4, thereby cooling the semiconductor element 2.

[0014] As shown in FIG. 1, the adhesive layer 4 has an area A bonded to the cooler 5 and an area B bonded to the circuit bus bar 3, and the area A is divided in the in-plane direction of the adhesive layer 4 to form a plurality of blocks, and the area B is inserted between the blocks of the area A and bonded to the cooler 5.

[0015] A method for forming the semiconductor module will now be described. The semiconductor module 1 is formed by applying a block of adhesive that forms region A on the cooler 5, solidifying or curing the adhesive, and then applying adhesive that forms region B to cover the adhesive in region A. The circuit bus bar 3 on which the semiconductor element 2 is mounted is placed on region B, and the adhesive that forms region B is solidified or cured, thereby adhering the circuit bus bar 3 and the cooler 5 together.

[0016] The above-mentioned region A is formed by placing a mask 6 with a horizontal top surface on a cooler 5, which has holes where the adhesive is to be applied, as shown in the top of Figure 2, applying the adhesive, rubbing the mask 6 with a squeegee to remove excess adhesive as shown in the middle of Figure 2, and then solidifying or curing the adhesive as shown in the bottom of Figure 2.

[0017] At this time, the portion of the mask 6 to which the adhesive is not applied acts as a beam and prevents the squeegee from bending, so that even if the surface on which the adhesive layer 4 is formed is wide, the thickness of region A can be strictly controlled by the thickness of the mask 6.

[0018] Then, by forming the region B after the adhesive that forms the region A has been solidified or hardened, the thickness of the region A, which has been controlled, can be maintained.

[0019] In other words, if the adhesive forming region A is not solidified or hardened and is still fluid, and the adhesive for region B is applied or the circuit bus bar 3 is placed on it, the adhesive in region A will flow or the circuit bus bar 3 will become embedded in the adhesive, causing a change in the thickness of region A, which has been controlled by the mask 6.

[0020] In the present invention, the adhesive that forms region A is solidified or hardened before forming region B, so the thickness of region A does not change and insulating performance can be ensured. Furthermore, since the thickness of region A is controlled by the thickness of mask 6 as described above, the thickness of each block is the same, so there is no variation in insulating properties between blocks and insulating reliability is improved.

[0021] As shown in the top of FIG. 3, the region B is formed by adjusting the thickness of the adhesive to be applied using a mask 6 that surrounds the entire area where the region B is to be formed.

[0022] The mask 6 for forming region B may be placed on the cooler 5 or on the formed region A. When placed on the cooler 5, a mask 6 adjusted to the thickness of the adhesive layer is used, and when placed on region A, a mask 6 adjusted to the thickness of region B to be formed on region A is used.

[0023] At this time, the solidified or hardened adhesive in region A supports the squeegee, preventing it from bending significantly and reducing the variation in the thickness of the entire adhesive layer. In addition, as shown at the bottom of Figure 3, the adhesive that forms region B penetrates between the blocks in region A and becomes integrated with region A, widening the heat transfer path and improving heat dissipation.

[0024] Furthermore, since the insulating properties of the adhesive layer 4 are ensured by the thickness of region A, the thickness of region B formed on region A is sufficient as long as it is thick enough to bond region A and the circuit bus bar 3 together.

[0025] Therefore, by placing the circuit bus bar 3 on the adhesive in region B while it is still fluid before solidifying or curing, and pressing it against region A which has already solidified or cured, and solidifying or curing the adhesive in region B, not only is the adhesion between the adhesive layer 4 and the circuit bus bar 3 improved, but the thickness of region B formed on region A can be made thinner, and heat dissipation properties are further improved, making it possible to achieve both insulation and heat dissipation properties.

[0026] If necessary, the adhesive layer 4 may contain an insulating filler such as aluminum oxide. When the adhesive layer 4 contains the insulating filler, the thermal conductivity of the adhesive layer 4 is improved, and the heat dissipation property can be improved.

[0027] Therefore, the insulating filler can be contained throughout the adhesive layer 4, but since adhesives containing fillers have reduced fluidity, if fillers are contained in the adhesive forming region B, it may be difficult for the fillers to penetrate between the blocks in region A.

[0028] In such a case, by including the filler in at least region A, the heat dissipation properties are improved.

[0029] The semiconductor element 2 provided on the circuit bus bar 3 is preferably disposed at a position overlapping with the block in the region A.

[0030] By arranging the semiconductor element 2 at a position overlapping the block of region A containing the filler, heat from the semiconductor element 2 is easily transferred to the cooler 5 via the block of region A, improving heat dissipation.

[0031] The adhesive that constitutes region A and region B should not cause deformation of the solidified or hardened adhesive in region A when the adhesive in region B is applied or hardened, and any combination of thermoplastic resins and thermosetting resins can be used.

[0032] Specifically, if the adhesive constituting region A is a thermosetting resin, there are no particular restrictions, but if the adhesive constituting region A is a thermoplastic resin, the softening temperature of the thermoplastic resin of the adhesive constituting region A must be higher than the softening temperature or hardening temperature of the adhesive constituting region B.

[0033] Table 1 shows the combinations of adhesives that make up area A and adhesives that make up area B, and how to distinguish between area A and area B.

[0034] [Table 1]

[0035] The adhesive layer 4 of the present invention can be distinguished into regions A and B by observing the cross section of the adhesive layer 4 and determining whether regions A and B correspond to any of the combinations shown in Table 1 above. [Explanation of symbols]

[0036] 1. Semiconductor module 2. Semiconductor elements 3-circuit busbar 4 Adhesive layer 41 Area A 42 Area B 5 Cooler 6. Mask 7 Squeegee

Claims

1. A semiconductor module in which a circuit bus bar provided with a semiconductor element and a cooler are bonded via an adhesive layer, the adhesive layer has a region A adhered to the cooler and a region B adhered to the circuit bus bar, the region A is divided in the in-plane direction of the adhesive layer to form a plurality of blocks, A semiconductor module characterized in that the region B is inserted between the blocks of the region A and is bonded to the cooler.

2. 2. The semiconductor module according to claim 1, wherein the plurality of blocks have the same thickness.

3. 3. The semiconductor module according to claim 2, wherein at least the region A contains a filler.

4. 4. The semiconductor module according to claim 3, wherein the semiconductor element is arranged at a position overlapping with a block in the region A.

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