Semiconductor module

Abstract

To provide a semiconductor module which effectively reduces heat resistance of a heat dissipation path and improves entire heat dissipation efficiency by exchanging a part of a tin layer with a material of high heat conductivity of a fin base.SOLUTION: In a semiconductor module 1, a substrate 10 includes a first metal surface 110 and a second metal surface 120 opposite to each other. A semiconductor element 20 is disposed on the first metal surface. A fin base 30 includes a first surface 301 and a second surface 302 opposite to each other. A plurality of heat dissipation fins 31 is disposed on the second surface of the fin base. A tin layer 40 is disposed between the second metal surface and the first surface of the fin base, so that the first surface of the fin base is close to the second metal surface. The fin base further includes a protruding step 32 disposed on the first surface of the fin base, and the protruding step has a center aligned with the semiconductor element.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semiconductor module, and in particular to the provision of cooling steps and replacing part of the tin layer with a fin-based material with high thermal conductivity, which effectively reduces the thermal resistance of the heat dissipation path and improves the overall heat dissipation efficiency. [Background technology]

[0002] As the operating frequency and operating current of semiconductor modules increase, the amount of heat generated per unit volume of semiconductor elements also increases. Conventional simple aluminum extrusion and die-cast cooling fins are machined, so the heat dissipation area is very limited and the area available for heat exchange with the surrounding air is also small. Therefore, even if a fan is installed, it cannot dissipate heat sufficiently and is not suitable for semiconductor module heat dissipation. For this reason, semiconductor modules generally use water-cooled heat dissipation.

[0003] In the prior art, the heat dissipation structure of a semiconductor module mainly involves welding a tin sheet to the semiconductor module and cooling fins, and then using a cooling fluid to directly contact the cooling fins to dissipate heat. After the semiconductor device generates heat, the heat is transferred to the cooling fins on the underside, and the cooling fluid flows through the cooling fins to remove the heat.

[0004] In this configuration, the tin layer that joins the semiconductor module and the cooling fins must be strong enough to be welded. However, because the tin layer has low thermal conductivity, the heat generated by the semiconductor chips mounted on the upper surface of the heat dissipation board cannot be quickly conducted to the cooling fins on the lower surface of the heat dissipation board for dissipation, reducing the heat dissipation effect of the heat dissipation board.

[0005] Therefore, in order to solve the drawbacks of the above technology, it is necessary to provide a heat dissipation structure for a semiconductor module that effectively reduces the thermal resistance of the heat dissipation path and improves the overall heat dissipation efficiency by providing a protrusion and replacing part of the tin layer with a fin-based material with high thermal conductivity. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to provide a semiconductor module that effectively reduces the thermal resistance of the heat dissipation path and improves the overall heat dissipation efficiency by providing cooling steps and replacing part of the tin layer with a fin-based material with high thermal conductivity.

[0007] Another object of the present invention is to provide a semiconductor module. When a semiconductor element, a substrate, a tin layer, and a fin base are stacked in this order, the same number of corresponding protrusions are provided on the surface of the fin base facing the semiconductor element to form an optimal heat dissipation path. Because the height of the protrusions is lower than the thickness of the original tin layer, the tin layer remains between the lower copper layer directly below the semiconductor element and the fin base, maintaining the bonding strength of the tin layer. The thickness of the tin layer below the semiconductor element is smaller than the thickness of the tin layer below the non-semiconductor element (i.e., the original thickness of the tin layer), and the tin layer, which has a relatively low thermal conductivity, is replaced with protrusions made of a material with high thermal conductivity, thereby improving the heat dissipation performance of the semiconductor element region. The number of protrusions and the number of semiconductor elements may be the same, and the planar areas of the protrusions and the planar areas of the semiconductor elements may be, for example, the same or similar. In the stacking direction, the protrusions are, for example, square, rectangular, triangular, circular, elliptical, or trapezoidal, and the horizontal cross section of the protrusions is, for example, rectangular, triangular, zigzag, trapezoid, or arc-shaped. This reduces the thermal resistance of the lower copper layer directly below the semiconductor element, allowing heat transfer to the fin base via the tin layer, and increases the bonding surface area of ​​the protrusions. In other words, providing a protrusion corresponding to the semiconductor element not only creates an optimal heat dissipation path, but also contributes to maintaining the bonding strength between the copper layer of the semiconductor module and the fin base. Furthermore, the thickness of the tin layer welded between the copper layer of the semiconductor module and the fin base ranges from 0.23 mm to 0.28 mm, and the height of the protrusion ranges from 0.15 mm to 0.25 mm. The maximum height of the protrusion is limited to be smaller than the original tin layer thickness. This reduces the amount of tin and improves the thermal resistance of the heat dissipation path without reducing the bonding strength between the tin layer and the copper layer and the fin base. This maintains the bonding strength of the semiconductor module and improves heat dissipation efficiency. [Means for solving the problem]

[0008] To achieve the above object, the present invention provides a semiconductor module having a substrate, a semiconductor element, a base, a plurality of cooling fins, and a tin layer. The substrate has a first metal surface and a second metal surface, the first metal surface and the second metal surface facing each other in space. The semiconductor element is provided on the first metal surface. The base has a first surface and a second surface, the first surface and the second surface facing each other in space. A plurality of cooling fins are provided on the second surface of the base. The tin layer is provided between the second metal surface and the first surface of the base. The base further has a protrusion protruding from the first surface of the base, and the center position of the protrusion is aligned with the semiconductor element along a first direction.

[0009] In one embodiment, the planar area of ​​the protrusion is larger than the planar area of ​​the semiconductor element and smaller than the planar area of ​​the substrate.

[0010] In one embodiment, the planar area of ​​the semiconductor element is larger than the planar area of ​​the protrusion and smaller than the planar area of ​​the substrate.

[0011] In one embodiment, the planar area of ​​the protrusion is equal to the planar area of ​​the semiconductor element and smaller than the planar area of ​​the substrate.

[0012] In one embodiment, the semiconductor element, the substrate, the tin layer, the protrusion, and the base are stacked in order along a first direction, and when viewed along the first direction, the protrusion is square, rectangular, triangular, circular, elliptical, or trapezoidal.

[0013] In one embodiment, the cross section of the convex portion is rectangular, triangular, zigzag, trapezoidal or arc-shaped when viewed along the second direction, and the second direction is perpendicular to the first direction.

[0014] In one embodiment, the thickness of the tin layer varies depending on the height of the protrusion.

[0015] In one embodiment, the thickness range of the tin layer is 0.23 mm to 0.28 mm.

[0016] In one embodiment, the height range of the convex portion is 0.15 mm to 0.25 mm.

[0017] In one embodiment, the substrate is a direct bonded aluminum (DBA) ceramic substrate or a direct bonded copper (DBC) ceramic substrate.

[0018] To achieve the above object, the present invention further provides a semiconductor module including a substrate, a semiconductor element, a fin base, and a tin layer. The substrate has a first metal surface and a second metal surface, which are opposed to each other in space. The semiconductor element is disposed on the first metal surface. The fin base has a first surface and a plurality of cooling fins, the first surface being attached to the second metal surface, and the plurality of cooling fins being thermally conductively bonded to the first surface. The tin layer is disposed between the second metal surface and the first surface of the fin base, with the first surface of the fin base being close to the second metal surface. The fin base further includes a protrusion protruding from the first surface of the fin base, and the semiconductor element, substrate, tin layer, protrusion, and fin base are sequentially stacked along a first direction, and the protrusion and the semiconductor element at least partially overlap when viewed along the first direction.

[0019] In one embodiment, when projected onto the second metal surface along the first direction, the projection of the semiconductor element on the second metal surface is included in the projection of the protrusion on the second metal surface.

[0020] In one embodiment, when projected onto the second metal surface along the first direction, the projection of the protrusion on the second metal surface is included in the projection of the semiconductor element on the second metal surface.

[0021] In an embodiment, when projected onto the second metal surface along the first direction, the projection of the protrusion on the second metal surface overlaps with the projection of the semiconductor element on the second metal surface.

[0022] In one embodiment, the bonding surface area of ​​the protrusion is greater than the projection of the second metal surface of the protrusion.

[0023] In one embodiment, the height of the protrusion is less than the separation distance from the second metal surface to the first surface.

[0024] In one embodiment, the number of semiconductor elements is equal to the number of protrusions.

[0025] In one embodiment, the plurality of heat dissipating fins and the protrusions of the fin base are integrally molded on opposite sides of the fin base. [Brief explanation of the drawings]

[0026] The following detailed description of the present invention and conceptual diagrams of examples are intended to enable those skilled in the art to fully understand the above content, but are not intended to limit the present invention. [Figure 1] 1 is a conceptual cross-sectional view of a semiconductor module according to a first embodiment of the present invention. [Figure 2] FIG. 10 is a conceptual cross-sectional view of a semiconductor module according to a second embodiment of the present invention. [Figure 3] FIG. 10 is a conceptual cross-sectional view of a semiconductor module according to a third embodiment of the present invention. [Figure 4] FIG. 10 is a conceptual cross-sectional view of a semiconductor module according to a fourth embodiment of the present invention. [Figure 5] FIG. 10 is a conceptual cross-sectional view of a semiconductor module according to a fifth embodiment of the present invention. [Figure 6] FIG. 10 is a conceptual cross-sectional view of a semiconductor module according to a sixth embodiment of the present invention. [Figure 7] FIG. 13 is a conceptual cross-sectional view of a semiconductor module according to a seventh embodiment of the present invention. [Figure 8] FIG. 2 is a plan view showing an example of a base having a protrusion according to the present invention. [Figure 9] FIG. 2 is a plan view showing an example of a base having a protrusion according to the present invention. [Figure 10] FIG. 2 is a plan view showing an example of a base having a protrusion according to the present invention. [Figure 11] FIG. 2 is a plan view showing an example of a base having a protrusion according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] Several exemplary embodiments embodying the features and advantages of the present invention are described in detail in the following description. While the present invention may be modified in various ways without departing from the scope of the present invention, it should be understood that these descriptions and drawings are illustrative in nature and not intended to limit the present invention. For example, the same reference numerals and / or labels may be used in different embodiments herein. This is for the purpose of simplicity and clarity of description and is not intended to limit the relationship between the various embodiments and / or the external structures described. Furthermore, spatial terms such as "upper," "lower," "inner," "outer," etc. may be used in the drawings to conveniently describe the relationship of one component or feature to another component(s) or feature(s). These spatial terms are used to encompass different orientations of the device during use or operation in addition to the orientation depicted in the drawings. The device may be in another orientation (e.g., rotated 90 degrees or at another orientation), and the spatial terms used should be interpreted accordingly. Furthermore, when a component is referred to as "connected" or "coupled to," this includes being directly connected or coupled to the other component, or being directly connected or coupled via another member, etc. Although values ​​and parameters in the broad ranges of values ​​herein are approximations, in certain examples, values ​​are described as precisely as possible. Furthermore, although terms such as "first" and "second" may be used to describe different elements in the claims of this application, it should be understood that these elements should not be limited by these terms and that in the examples, these elements are described by corresponding symbols of different elements. These terms are used to distinguish between different elements. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the examples. As used herein, the term "and / or" encompasses any and all combinations of one or more of the associated exemplified items.

[0028] FIG. 1 is a cross-sectional conceptual diagram of a semiconductor module according to a first embodiment of the present invention. The present invention provides a water-cooled heat dissipation structure applicable to a semiconductor module. The semiconductor module 1 includes a substrate 10, a semiconductor element 20, a base (also referred to as a fin base) 30, a plurality of cooling fins 31, and a tin layer 40. The substrate 10 is, for example, a DBA (Direct Bonded Aluminum) ceramic substrate or a DBC (Direct Bonded Copper) ceramic substrate. The substrate 10 is configured by disposing a ceramic layer 13 between a first metal layer 11 and a second metal layer 12, and has a first metal surface 110 and a second metal surface 120. The first metal surface 110 and the second metal surface 120 face each other in space and are the upper and lower surfaces of the substrate 10, which are opposite surfaces. In this embodiment, the semiconductor element 20 is, for example, a power chip, and is provided on the first metal surface 110 of the substrate 10. In this embodiment, the base 30 has a first surface 301 and a second surface 302, which are opposed to each other in space and are upper and lower surfaces. A plurality of cooling fins 31 are provided on the second surface 302 of the base 30. In this embodiment, the base 30 further has a protrusion 32 protruding from the first surface 301 of the base 30, and the center position of the protrusion 32 is aligned with the semiconductor element 20 along the first direction. The number of protrusions 32 is equal to the number of semiconductor elements 20. The base 30 may further be, for example, a water-cooled fin base, and the plurality of cooling fins 31 and the protrusion 32 of the base 30 are integrally molded on the second surface 302 and the first surface 301 of the base 30. The plurality of cooling fins 31 on the second surface 302 can remove heat by heat exchange with a cooling fluid (not shown). Of course, the present invention is not limited to this. In this embodiment, the tin layer 40 is provided between the second metal surface 120 of the substrate 10 and the first surface 301 of the base 30 to adhere the first surface 301 of the base 30 to the second metal surface 120 of the substrate 10 .

[0029] In this embodiment, the semiconductor element 20, substrate 10, tin layer 40, protrusion 32, base 30, and cooling fin 31 are stacked in this order from top to bottom along a first direction (Z-axis direction). The protrusion 32 and semiconductor element 20 at least partially overlap in the first direction (Z-axis direction). In this embodiment, the planar area (footprint) S2 of the protrusion 32 is equal to the planar area S1 of the semiconductor element 20 and is smaller than the planar area (not shown) of the substrate 10. Because the center position of the protrusion 32 is aligned with the semiconductor element 20, the projection of the protrusion 32 on the second metal surface 120 and the projection of the semiconductor element 20 on the second metal surface 120 overlap with each other in the first direction (Z-axis direction). In this embodiment, the substrate 10 and base 30 are joined by welding the tin layer 40. In the present invention, the same number of protrusions 32 are provided on the first surface 301 of the base 30 facing the semiconductor element 20, forming an optimal heat dissipation path P. In this embodiment, a separation distance D is provided between the second metal surface 120 of the substrate 10 and the first surface 301 of the base 30, and a tin layer 40 is filled therein. This separation distance D corresponds to the original thickness of the tin layer 40. In this embodiment, the separation distance D or the thickness of the tin layer 40 ranges from 0.23 mm to 0.28 mm. Furthermore, the height H of the protrusions 32 protruding from the first surface 301 ranges from 0.15 mm to 0.25 mm. The height H of the protrusions 32 is maintained smaller than the separation distance D between the second metal surface 120 and the first surface 301. Because the height H of the protrusions 32 is smaller than the thickness (separation distance D) of the original tin layer 40, the tin layer 40 remains between the second metal layer 12 below the semiconductor element 20 and the base 30, maintaining the bonding strength between them. The thickness of the tin layer below the semiconductor element 20 (the difference between the separation distance D and the height H) is smaller than the thickness of the tin layer below the non-semiconductor element (separation distance D), and by replacing the tin layer 40, which has a relatively low thermal conductivity, with the protrusions 32 made of a material with high thermal conductivity, the heat dissipation performance of the semiconductor element 20 area is improved, and the overall heat dissipation efficiency is improved by the optimal heat dissipation path P.

[0030] Meanwhile, in this embodiment, the cross section of the protrusion 32 in the second direction (Y-axis direction) is, for example, rectangular, and the second direction is perpendicular to the first direction. In other embodiments, the second direction may also be the X-axis direction or a direction parallel to the XY plane, but the present invention is not limited thereto. As a result, the protrusion 32 further forms a bonding surface 320 on the first surface 301 and has a top surface and four side walls. In other words, the bonding surface area of ​​the bonding surface 320 is larger than the projected area (planar area S2) of the protrusion 32 on the second metal surface 120. By providing the protrusion 32 corresponding to the semiconductor element 20, not only is an optimal heat dissipation path P formed, but the bonding surface area of ​​the welding between the substrate 10 and the base 30 is increased, contributing to maintaining the bonding strength between the second metal layer 12 of the substrate 10 and the base 30.

[0031] FIG. 2 is a cross-sectional conceptual diagram of a semiconductor module according to a second embodiment of the present invention. In this embodiment, semiconductor module 1a is similar to semiconductor module 1 shown in FIG. 1, and the same reference numerals denote the same components, structures, and functions, so their description will be omitted. In this embodiment, semiconductor element 20, substrate 10, tin layer 40, protrusion 32a, base 30, and cooling fin 31 are stacked in this order from top to bottom along a first direction (Z-axis direction). In the first direction (Z-axis direction), the projection of protrusion 32a on second metal surface 120 is included in semiconductor element 20 on second metal surface 120. Planar area (footprint) S2 of protrusion 32a is smaller than planar area S1 of semiconductor element 20 and smaller than planar area (not shown) of substrate 10. Furthermore, in this embodiment, the cross section of the protrusion 32a in the second direction (Y-axis direction) is, for example, rectangular, and the bonding surface 320 formed on the first surface 301 of the protrusion 32a has a bonding surface area larger than the planar area S2 of the protrusion 32a. By limiting the maximum height H of the protrusion 32a to be smaller than the original thickness of the tin layer 40 (separation distance D), it is possible to reduce the amount of tin layer 40 used and improve the thermal resistance in the heat dissipation path P without impairing the bonding of the tin layer 40 between the second metal layer 12 and the base 30. As a result, the semiconductor module 1a maintains bonding strength and improves heat dissipation efficiency.

[0032] FIG. 3 is a cross-sectional conceptual diagram of a semiconductor module according to a third embodiment of the present invention. In this embodiment, semiconductor module 1b is similar to the semiconductor module shown in FIG. 1, and the same reference numerals denote the same components, structures, and functions, so their description will be omitted. In this embodiment, semiconductor element 20, substrate 10, tin layer 40, protrusion 32b, base 30, and cooling fin 31 are stacked in this order from top to bottom along a first direction (Z-axis direction). When projected onto second metal surface 120 along the first direction (Z-axis direction), the projection of semiconductor element 20 on second metal surface 120 is included in the projection of protrusion 32b on second metal surface 120. In other words, the planar area (footprint) S2 of protrusion 32b is larger than the planar area S1 of semiconductor element 20 and smaller than the planar area (not shown) of substrate 10. Furthermore, in this embodiment, the cross section of the protrusion 32b in the second direction (Y-axis direction) is, for example, rectangular, and the bonding surface 320 formed on the first surface 301 of the protrusion 32b has a bonding surface area larger than the planar area S2 of the protrusion 32b. By limiting the maximum height H of the protrusion 32b to be smaller than the original thickness of the tin layer 40 (separation distance D), it is possible to reduce the amount of tin layer 40 used and improve the thermal resistance in the heat dissipation path P without impairing the bonding of the tin layer 40 between the second metal layer 12 and the base 30. As a result, the semiconductor module 1b maintains bonding strength and improves heat dissipation efficiency.

[0033] FIG. 4 is a cross-sectional conceptual diagram of a semiconductor module according to a fourth embodiment of the present invention. In this embodiment, the semiconductor module 1c is similar to the semiconductor module shown in FIG. 1, and the same reference numerals denote the same components, structures, and functions, so their description will be omitted. In this embodiment, the semiconductor element 20, the substrate 10, the tin layer 40, the protrusion 32c, the base 30, and the cooling fin 31 are stacked in this order from top to bottom along the first direction (Z-axis direction). In the first direction (Z-axis direction), the projection of the semiconductor element 20 on the second metal surface 120 overlaps with the projection of the protrusion 32c on the second metal surface 120. In other words, the planar area (footprint) S2 of the protrusion 32c is equal to the planar area S1 of the semiconductor element 20 and smaller than the planar area of ​​the substrate 10 (not shown). In this embodiment, the cross section of the protrusion 32c in the second direction (Y-axis direction) is, for example, triangular, and the bonding surface 320 formed on the first surface 301 of the protrusion 32c has a bonding surface area larger than the planar area S2 of the protrusion 32c. By limiting the maximum height H of the protrusion 32c to be smaller than the original thickness of the tin layer 40 (separation distance D), when the tin layer 40 is previously provided between the first surface 301, the bonding surface 320, and the second metal surface 120, the thickness of the tin layer 40 varies depending on the height H of the protrusion 32c, reducing the amount of tin layer 40 used and preventing damage to the bond between the tin layer 40 and the second metal layer 12 and base 30 due to gaps occurring at the outer periphery of the protrusion 32c. This allows the semiconductor module 1c to maintain bonding strength and improve heat dissipation efficiency.

[0034] FIG. 5 is a cross-sectional conceptual diagram of a semiconductor module according to a fifth embodiment of the present invention. In this embodiment, semiconductor module 1d is similar to semiconductor module 1c shown in FIG. 4, and the same reference numerals denote the same components, structures, and functions, so their description will be omitted. In this embodiment, semiconductor element 20, substrate 10, tin layer 40, protrusion 32d, base 30, and cooling fin 31 are stacked in this order from top to bottom along a first direction (Z-axis direction). In the first direction (Z-axis direction), the projection of semiconductor element 20 on second metal surface 120 overlaps with the projection of protrusion 32d on second metal surface 120. In other words, the planar area (footprint) S2 of protrusion 32d is equal to the planar area S1 of semiconductor element 20 and smaller than the planar area of ​​substrate 10 (not shown). In this embodiment, the cross section of the protrusion 32d in the second direction (Y-axis direction) is, for example, trapezoidal, and the bonding surface 320 formed on the first surface 301 of the protrusion 32d has a bonding surface area larger than the planar area S2 of the protrusion 32d. By limiting the maximum height H of the protrusion 32d to be smaller than the original thickness of the tin layer 40 (separation distance D), when the tin layer 40 is previously provided between the first surface 301, the bonding surface 320, and the second metal surface 120, the thickness of the tin layer 40 varies depending on the height H of the protrusion 32d, reducing the amount of tin layer 40 used and preventing damage to the bonding between the tin layer 40 and the second metal layer 12 and base 30 due to gaps occurring at the outer periphery of the protrusion 32d. This allows the semiconductor module 1d to maintain bonding strength and improve heat dissipation efficiency.

[0035] FIG. 6 is a cross-sectional conceptual diagram of a semiconductor module according to a sixth embodiment of the present invention. In this embodiment, semiconductor module 1e is similar to semiconductor module 1c shown in FIG. 4, and the same reference numerals denote the same components, structures, and functions, so their description will be omitted. In this embodiment, semiconductor element 20, substrate 10, tin layer 40, protrusion 32e, base 30, and cooling fin 31 are stacked in this order from top to bottom along a first direction (Z-axis direction). In the first direction (Z-axis direction), the projection of semiconductor element 20 on second metal surface 120 overlaps with the projection of protrusion 32e on second metal surface 120. In other words, the planar area (footprint) S2 of protrusion 32e is equal to the planar area S1 of semiconductor element 20 and smaller than the planar area (not shown) of substrate 10. In this embodiment, the cross section of the protrusion 32e in the second direction (Y-axis direction) is, for example, arc-shaped, and the bonding surface 320 formed on the first surface 301 of the protrusion 32e has a bonding surface area larger than the planar area S2 of the protrusion 32e. By limiting the maximum height H of the protrusion 32e to be smaller than the original thickness of the tin layer 40 (i.e., the separation distance D), when the tin layer 40 is previously provided between the first surface 301, the bonding surface 320, and the second metal surface 120, the thickness of the tin layer 40 varies depending on the height H of the protrusion 32e. This reduces the amount of tin layer 40 used and prevents damage to the bond between the tin layer 40 and the second metal layer 12 and base 30 due to gaps occurring around the outer periphery of the protrusion 32e. This allows the semiconductor module 1e to maintain bonding strength and improve heat dissipation efficiency.

[0036] FIG. 7 is a cross-sectional conceptual diagram of a semiconductor module according to a seventh embodiment of the present invention. In this embodiment, the semiconductor module 1f is similar to the semiconductor module 1c shown in FIG. 4, and the same reference numerals denote the same components, structures, and functions, so their description will be omitted. In this embodiment, the semiconductor element 20, the substrate 10, the tin layer 40, the protrusion 32f, the base 30, and the cooling fin 31 are stacked in this order from top to bottom along the first direction (Z-axis direction). In the first direction (Z-axis direction), the projection of the semiconductor element 20 on the second metal surface 120 overlaps with the projection of the protrusion 32f on the second metal surface 120. In other words, the planar area (footprint) S2 of the protrusion 32f is equal to the planar area S1 of the semiconductor element 20 and smaller than the planar area of ​​the substrate 10 (not shown). In this embodiment, the cross section of the protrusion 32f in the second direction (Y-axis direction) is, for example, zigzag-shaped, and the bonding surface 320 formed on the first surface 301 of the protrusion 32f has a bonding surface area larger than the planar area S2 of the protrusion 32f. By limiting the maximum height H of the protrusion 32f to be smaller than the original thickness of the tin layer 40 (separation distance D), when the tin layer 40 is previously provided between the first surface 301, the bonding surface 320, and the second metal surface 120, the thickness of the tin layer 40 varies depending on the height H of the protrusion 32f, reducing the amount of tin layer 40 used and preventing damage to the bonding between the tin layer 40 and the second metal layer 12 and the base 30 due to gaps occurring at the outer periphery of the protrusion 32f. This allows the semiconductor module 1f to maintain bonding strength and improve heat dissipation efficiency.

[0037] 8 to 11 are plan views showing various embodiments of a base having a protrusion according to the present invention. In these embodiments, the bases 30g, 30h, 30i, and 30j are similar to the base 30 shown in FIG. 1, and the same reference numerals denote the same components, structures, and functions, so their description will be omitted. Please refer to FIGS. 1 and 8 to 11. In one embodiment, the semiconductor element 20, the substrate 10, the tin layer 40, the protrusion 32g, the base 30g, and the cooling fin 31 are stacked in this order from top to bottom along the first direction (Z-axis direction). In the first direction (Z-axis direction), the protrusion 32g is circular (as shown in FIG. 8). The planar area S2 of the protrusion 32g may be close to the planar area S1 of the semiconductor element 20. When the center position of the protrusion 32g is aligned with the semiconductor element 20, providing the protrusion 32g allows a portion of the tin layer 40 to be replaced with the material of the fin base 30g with high thermal conductivity, effectively reducing the thermal resistance of the heat dissipation path and improving overall heat dissipation efficiency. In another embodiment, the semiconductor element 20, the substrate 10, the tin layer 40, the protrusion 32h, the base 30h, and the cooling fin 31 are stacked in this order from top to bottom along the first direction (Z-axis direction). In the first direction (Z-axis direction), the protrusion 32h is square (as shown in FIG. 9 ). The planar area S2 of the protrusion 32h may be close to the planar area S1 of the semiconductor element 20. When the center position of the protrusion 32h is aligned with the semiconductor element 20, providing the protrusion 32h allows a portion of the tin layer 40 to be replaced with the material of the fin base 30h with high thermal conductivity, effectively reducing the thermal resistance of the heat dissipation path and improving overall heat dissipation efficiency. In another embodiment, the semiconductor element 20, the substrate 10, the tin layer 40, the protrusions 32i, the base 30i, and the cooling fins 31 are stacked in this order from top to bottom along a first direction (Z-axis direction). In the first direction (Z-axis direction), the protrusions 32i are triangular (as shown in FIG. 10). The planar area S2 of the protrusions 32i may be close to the planar area S1 of the semiconductor element 20. When the center positions of the protrusions 32i are aligned with the semiconductor element 20, providing the protrusions 32i allows a portion of the tin layer 40 to be replaced with the highly thermally conductive material of the fin base 30i, effectively reducing the thermal resistance of the heat dissipation path and improving overall heat dissipation efficiency.In another embodiment, the semiconductor element 20, the substrate 10, the tin layer 40, the protrusion 32j, the base 30j, and the cooling fin 31 are stacked in this order from top to bottom along the first direction (Z-axis direction). In the first direction (Z-axis direction), the protrusion 32j is trapezoidal (as shown in FIG. 11 ). The planar area S2 of the protrusion 32j may be close to the planar area S1 of the semiconductor element 20. When the center position of the protrusion 32j is aligned with the semiconductor element 20, providing the protrusion 32j allows a portion of the tin layer 40 to be replaced with the highly thermally conductive material of the fin base 30j, effectively reducing the thermal resistance of the heat dissipation path and improving overall heat dissipation efficiency. Of course, in other embodiments, the protrusion 32 may have an elliptical or other symmetrical shape when viewed along the first direction (Z-axis direction). By aligning the center position of the protrusion 32 with the semiconductor element 20, a portion of the tin layer 40 can be replaced with a material of high thermal conductivity of the fin base 30, thereby achieving the purpose of improving the structural strength and heat dissipation efficiency, but the present invention is not limited to this.

[0038] Based on the above, the present invention provides a semiconductor module that effectively reduces the thermal resistance of the heat dissipation path and improves overall heat dissipation efficiency by providing protrusions and replacing a portion of the tin layer with a fin base material with high thermal conductivity. When a semiconductor element, a substrate, a tin layer, and a fin base are stacked in this order, the same number of corresponding protrusions are provided on the surface of the fin base facing the semiconductor element to form an optimal heat dissipation path. The height of the protrusions is smaller than the original thickness of the tin layer, and the tin layer remains between the lower copper layer directly below the semiconductor element and the fin base, thereby maintaining the bonding strength of the tin layer. The thickness of the tin layer below the semiconductor element is smaller than the thickness of the tin layer below the non-semiconductor element (original tin layer thickness). By replacing the tin layer with a relatively low thermal conductivity by protrusions made of a material with high thermal conductivity, the heat dissipation performance of the semiconductor element region is improved. The number of protrusions may be the same as the number of semiconductor elements, and the planar area of ​​the protrusions may be equal to or close to the planar area of ​​the semiconductor element. In the stacking direction, the convex portion is, for example, square, rectangular, triangular, circular, elliptical, or trapezoidal, and the horizontal cross section of the convex portion is, for example, rectangular, triangular, zigzag, trapezoidal, or arc-shaped. This reduces the thermal resistance of the lower copper layer directly below the semiconductor element, allowing heat transfer to the fin base via the tin layer, and increases the bonding surface area of ​​the convex portion. In other words, providing the convex portion corresponding to the semiconductor element not only forms an optimal heat dissipation path, but also contributes to maintaining the bonding strength between the copper layer of the semiconductor module and the fin base. Furthermore, by limiting the thickness of the tin layer welded between the copper layer of the semiconductor module and the fin base to 0.23 mm to 0.28 mm, and the height of the convex portion to 0.15 mm to 0.25 mm, and limiting the maximum height of the convex portion to less than the original tin layer thickness, the amount of tin layer used can be reduced without compromising the bonding of the tin layer between the copper layer and the base, improving the thermal resistance of the heat dissipation path. This allows the semiconductor module to maintain bonding strength and improve heat dissipation efficiency.

[0039] The present invention can be modified in various ways by those skilled in the art, but these modifications do not depart from the scope of the present invention. [Explanation of symbols]

[0040] 1, 1a, 1b, 1c, 1d, 1e, 1f: semiconductor modules 10: Circuit board 11: 1st metal layer 110: 1st metal surface 12: Second metal layer 120:Second metal surface 13: Ceramic layer 20: Semiconductor element 30, 30a, 30b, 30c, 30d, 30e, 30f, 30g, 30h, 30i, 30j: Base 301: 1st surface 302:Second surface 31: Cooling fin 32, 32a, 32b, 32c, 32d, 32e, 32f, 32g, 32h, 32i, 32j: convex parts 320: Joint surface 40: Tin layer D: Separation distance H: Height P: Heat dissipation path S1, S2 plane area X, Y, Z: Axes

Claims

1. a substrate having a first metal surface and a second metal surface facing each other in space; a semiconductor element disposed on the first metal surface; a base having a first surface and a second surface facing each other in space; a plurality of heat dissipation fins provided on the second surface of the base; a tin layer disposed between the second metal surface and the first surface of the base; The base further has a protrusion protruding from the first surface, and the center position of the protrusion is aligned with the semiconductor element along the first direction.

2. 2. The semiconductor module according to claim 1, wherein the planar area of ​​the protrusion is larger than the planar area of ​​the semiconductor element and smaller than the planar area of ​​the substrate.

3. 2. The semiconductor module according to claim 1, wherein a planar area of ​​the semiconductor element is larger than a planar area of ​​the protrusion and smaller than a planar area of ​​the substrate.

4. 2. The semiconductor module according to claim 1, wherein the planar area of ​​the protrusion is equal to the planar area of ​​the semiconductor element and smaller than the planar area of ​​the substrate.

5. 2. The semiconductor module of claim 1, wherein the semiconductor element, the substrate, the tin layer, the convex portion, and the base are stacked in order in the first direction, and when viewed along the first direction, the convex portion is square, rectangular, triangular, circular, elliptical, or trapezoidal.

6. 6. The semiconductor module according to claim 5, wherein a cross section of the convex portion is rectangular, triangular, sawtooth, trapezoidal, or arcuate when viewed from a second direction, and the second direction is perpendicular to the first direction.

7. The semiconductor module according to claim 1 , wherein the thickness of the tin layer varies depending on the height of the protrusion.

8. 2. The semiconductor module according to claim 1, wherein the thickness of the tin layer ranges from 0.23 mm to 0.28 mm.

9. 2. The semiconductor module according to claim 1, wherein the height of said protrusions ranges from 0.15 mm to 0.25 mm.

10. 2. The semiconductor module according to claim 1, wherein the substrate is a DBA (Direct Bonded Aluminum) ceramic substrate or a DBC (Direct Bonded Copper) ceramic substrate.

11. a substrate having a first metal surface and a second metal surface facing each other in space; a semiconductor element disposed on the first metal surface; a fin base having a first surface and a plurality of heat dissipation fins, the first surface being attached to the second metal surface, and the plurality of heat dissipation fins being joined to the first surface in a heat-conductive manner; a tin layer disposed between the second metal surface and the first surface of the fin base; a semiconductor module, wherein the fin base further has a convex portion protruding from the first surface, the semiconductor element, the substrate, the tin layer, the convex portion, and the fin base are stacked in order in a first direction, and the convex portion and the semiconductor element overlap at least partially when viewed along the first direction.

12. The semiconductor module according to claim 11 , wherein when projected onto the second metal surface along the first direction, a projection of the semiconductor element on the second metal surface is included in a projection of a convex portion on the second metal surface.

13. The semiconductor module according to claim 11 , wherein when projected onto the second metal surface along the first direction, a projection of the convex portion on the second metal surface is included in a projection of the semiconductor element on the second metal surface.

14. The semiconductor module according to claim 11 , wherein when projected onto the second metal surface along the first direction, a projection of the convex portion on the second metal surface overlaps a projection of the semiconductor element on the second metal surface.

15. The semiconductor module according to claim 11 , wherein a bonding surface area of ​​the protrusion is larger than a projection of the protrusion onto the second metal surface.

16. The semiconductor module according to claim 11 , wherein the height of the protrusion is smaller than a distance from the second metal surface to the first surface.

17. The semiconductor module according to claim 11 , wherein the number of the semiconductor elements is equal to the number of the protrusions.

18. The semiconductor module according to claim 11 , wherein the plurality of heat dissipation fins and the protrusions of the fin base are integrally formed on both opposing surfaces of the fin base.

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