Semiconductor element mounting substrate

Abstract

This semiconductor element mounting substrate is provided with: a heat sink that has a pair of main surfaces, is formed from metal, and has a fin section comprising a plurality of recesses and protrusions on one main surface from among the pair of main surfaces; an electrode that is arranged on the other main surface side from among the pair of main surfaces of the heat sink, and that is connected to a semiconductor element; and an insulating layer that is arranged between the electrode and the other main surface of the heat sink, and that is formed from ceramic.

Description

Substrate for mounting semiconductor device 【0001】 The present invention relates to a substrate for mounting a semiconductor device. 【0002】 Conventionally, a substrate for mounting a semiconductor device provided with a heat sink for releasing heat of a semiconductor device connected to an electrode has been known (for example, Patent Documents 1 and 2). 【0003】 International Publication No. 2016 / 035680, Japanese Patent Application Laid-Open No. 2015-035501 【0004】 However, even with the prior art such as Patent Documents 1 and 2, there is still room for improvement in the technology for reducing the size of the substrate for mounting a semiconductor device while maintaining insulation between the heat sink and the electrode. 【0005】 An object of the present invention is to provide a technique for reducing the size of a substrate for mounting a semiconductor device while maintaining insulation between a heat sink and an electrode. 【0006】 The present invention has been made to solve at least a part of the above problems and can be realized in the following forms. 【0007】 (1) According to one aspect of the present invention, a substrate for mounting a semiconductor device is provided. This substrate for mounting a semiconductor device has a pair of main surfaces and is a heat sink formed of metal, and has a fin portion formed of a plurality of irregularities on one of the pair of main surfaces, and the heat sink has the pair of main surfaces. An electrode disposed on the other main surface side and connected to a semiconductor device, and an insulating layer disposed between the other main surface of the heat sink and the electrode and formed of ceramic. 【0008】 According to this configuration, an insulating layer formed of ceramic is disposed between the heat sink having the fin portion and the electrode. The insulating layer formed of ceramic can be formed relatively thin while maintaining insulation between the heat sink formed of metal and the electrode. Thereby, the substrate for mounting a semiconductor device can be reduced in size while maintaining insulation between the heat sink and the electrode. 【0009】(2) The semiconductor element mounting substrate of the above configuration may further include an intermediate layer disposed between the other main surface of the heat sink and the insulating layer. With this configuration, the semiconductor element mounting substrate includes an intermediate layer disposed between the heat sink and the insulating layer. The intermediate layer can alleviate the stress generated by the difference in thermal expansion between the heat sink and the insulating layer, while improving both the bonding strength between the heat sink and the insulating layer and the rigidity of the semiconductor element mounting substrate. This makes it possible to suppress the occurrence of defects in the semiconductor element mounting substrate. 【0010】 (3) In the semiconductor element mounting substrate of the above configuration, the insulating layer may be formed of aluminum nitride. With this configuration, the insulating layer is formed of aluminum nitride, which has a relatively high thermal conductivity. This allows the heat from the semiconductor element to be efficiently transferred to the heat sink. Therefore, it is possible to suppress the occurrence of malfunctions in the semiconductor element mounting substrate due to temperature rise. 【0011】 (4) In the semiconductor element mounting substrate of the above configuration, the thickness of the insulating layer may be 10 μm or less. With this configuration, since the thickness of the insulating layer is 10 μm or less, the semiconductor element mounting substrate can be made even smaller. 【0012】 (5) In the semiconductor element mounting substrate of the above configuration, the heat sink may have a vapor chamber. With this configuration, the heat sink has a vapor chamber that can efficiently transfer heat from one side to the other side. This allows for efficient transfer of heat from the semiconductor element connected to the electrode, thereby improving the heat dissipation performance of the semiconductor element mounting substrate. 【0013】 (6) In the semiconductor element mounting substrate of the above form, at least a portion of the fin portion may be a mesh member. With this configuration, at least a portion of the fin portion is a mesh member, and the contact area with the fluid flowing between the multiple irregularities is relatively large. As a result, heat from the semiconductor element connected to the electrode can be efficiently released through the fin portion, thereby improving the heat dissipation performance of the semiconductor element mounting substrate. 【0014】(7) In the semiconductor element mounting substrate of the above form, the heat sink has a plate-like portion having the other main surface, and the fin portion is arranged on the plate-like portion on the opposite side from the insulating layer, and may have a plurality of columnar portions whose tip surfaces form the one main surface. With this configuration, the fin portion has a plurality of columnar portions whose tip surfaces form the one main surface of the heat sink. This allows the design of the heat sink to be changed by changing the length of the columnar portions or the size of the tip surfaces. Therefore, the heat of the semiconductor element connected to the electrode can be efficiently released, and the heat dissipation performance of the semiconductor element mounting substrate can be improved. 【0015】 (8) In the semiconductor element mounting substrate of the above form, the material forming the plate-shaped portion and the material forming the columnar portion may be different. In this configuration, the material forming the plate-shaped portion and the material forming the columnar portion are different. This makes it possible to adjust the weight of the heat sink without reducing the heat dissipation performance of the heat sink. 【0016】 Furthermore, the present invention can be realized in various forms, for example, in the form of a product including a substrate having an insulating layer, a substrate for mounting semiconductor elements, a semiconductor package including a substrate for mounting semiconductor elements on which semiconductor elements are mounted, a method for manufacturing the semiconductor substrate and the semiconductor package. 【0017】 This is a schematic cross-sectional view of a semiconductor element mounting substrate according to the first embodiment. This is a schematic cross-sectional view of a semiconductor element mounting substrate according to a comparative example. This is a schematic cross-sectional view of a semiconductor element mounting substrate according to the second embodiment. This is the first figure illustrating the manufacturing method of the semiconductor element mounting substrate according to the second embodiment. This is the second figure illustrating the manufacturing method of the semiconductor element mounting substrate according to the second embodiment. This is a schematic cross-sectional view of a semiconductor element mounting substrate according to the third embodiment. This is a schematic cross-sectional view of a semiconductor element mounting substrate according to the fourth embodiment. This is a schematic cross-sectional view of a semiconductor element mounting substrate according to the fifth embodiment. This is a schematic cross-sectional view of a first modified example of the semiconductor element mounting substrate according to the fifth embodiment. This is a schematic cross-sectional view of a second modified example of the semiconductor element mounting substrate according to the fifth embodiment. 【0018】<First Embodiment> Figure 1 is a schematic cross-sectional view of a semiconductor element mounting substrate 1 according to the first embodiment. The semiconductor element mounting substrate 1 of this embodiment supports optical semiconductors such as light-emitting diodes (LEDs) and semiconductor lasers (LDs) as semiconductor elements SE via electrodes 40, and functions as a heat dissipation substrate that releases heat generated during light emission to the outside. The semiconductor element mounting substrate 1 comprises a heat sink 10, an intermediate layer 20, an insulating layer 30, and electrodes 40. Note that the thickness relationships of the heat sink 10, the intermediate layer 20, the insulating layer 30, and the electrodes 40 in Figure 1 are shown differently from the actual thickness relationships for the sake of explanation. 【0019】 The heat sink 10 has a pair of main surfaces 10a and 10b and is made of metal. The heat sink 10 has a fin portion 11 consisting of a plurality of irregularities on one of the pair of main surfaces 10a and 10b, 10a. In this embodiment, the heat sink 10 is made of aluminum (Al). The heat sink 10 may be made of copper (Cu), a material mainly composed of copper, a material mainly composed of aluminum, or a ceramic matrix composite (CMC). Here, "main component" refers to a component that accounts for more than 50% by mass in the material in question. The heat sink 10 may be made of an alloy of copper and aluminum. By forming the heat sink 10 from these metals, the heat from the semiconductor element SE can be efficiently released to the outside through the heat sink 10. 【0020】The intermediate layer 20 is placed between the other main surface 10b of the heat sink 10 and the insulating layer 30. The intermediate layer 20 improves the rigidity of the semiconductor element mounting substrate 1 by bringing the heat sink 10 and the insulating layer 30 into close contact, and also relieves the stress generated by the difference in thermal expansion between the heat sink 10 and the insulating layer 30, thereby suppressing the occurrence of cracks in the insulating layer 30 due to the difference in thermal expansion coefficients between the heat sink 10 and the insulating layer 30. In this embodiment, the intermediate layer 20 is made of titanium (Ti). The thickness of the intermediate layer 20 is, for example, 0.5 μm. The material forming the intermediate layer 20 is not limited to titanium, but may be chromium (Cr), molybdenum (Mo), or other materials that have good adhesion to the insulating layer. It is desirable that the material forming the intermediate layer 20 has a thermal expansion coefficient value that is between the thermal expansion coefficient of the material forming the heat sink 10 and the thermal expansion coefficient of the material forming the insulating layer 30. In this embodiment, the intermediate layer 20 is formed over the entire surface of the other main surface 10b of the pair of main surfaces 10a and 10b of the heat sink 10. 【0021】 The insulating layer 30 is positioned between the heat sink 10 and the electrode 40, more specifically, between the intermediate layer 20 and the electrode 40. The insulating layer 30 is made of ceramic. In this embodiment, the insulating layer 30 is made of aluminum nitride (AlN). The thickness of the insulating layer 30 is 1 μm or more and 10 μm or less. The material used to form the insulating layer 30 is not limited to aluminum nitride, but may also be alumina (Al2O3), silicon nitride (SiN), silicon oxide (SiO2), etc. 【0022】 The insulating layer 30 in this embodiment is formed of amorphous aluminum nitride. This improves resistance to cracks that may occur in the insulating layer 30. The insulating layer 30 in this embodiment is formed on the entire surface 20a of the intermediate layer 20 that is opposite to the heat sink 10. 【0023】The electrode 40 is positioned on the other main surface 10b of the pair of main surfaces 10a and 10b of the heat sink 10. More specifically, the electrode 40 is positioned on the opposite side from the heat sink 10 to the insulating layer 30 which is located on the other main surface 10b of the heat sink 10. The electrode 40 is connected to the semiconductor element SE. The electrode 40 is made of gold (Au). The thickness of the electrode 40 is, for example, 3.0 μm. The electrode 40 has a predetermined pattern shape so as to connect to a predetermined location on the mounted semiconductor element SE. Note that the material forming the electrode 40 is not limited to gold, but may be made of copper (Cu). 【0024】 Next, the manufacturing method of the semiconductor element mounting substrate 1 of this embodiment will be described. In the manufacturing of the semiconductor element mounting substrate 1, first, a component that will become a heat sink 10 is fabricated by processing. Specifically, a fin portion 11 is formed on one of the main surfaces of a flat aluminum component. Next, on the aluminum component on which the fin portion 11 is formed, an intermediate layer 20 made of titanium is deposited on the main surface opposite to the main surface on which the fin portion 11 is formed. The intermediate layer 20 is deposited by chemical vapor deposition (CVD) or physical vapor deposition (PVD). 【0025】 Next, an insulating layer 30 is formed on the intermediate layer 20. In this embodiment, the insulating layer 30 is formed by a vapor deposition method such as sputtering, vapor deposition, or CVD. It is desirable that the insulating layer 30 be amorphous by controlling the deposition conditions during deposition. In the manufacturing method of the semiconductor device mounting substrate 1 of this embodiment, the insulating layer 30 is formed by sputtering. The insulating layer 30, which is formed of amorphous aluminum nitride, is formed on the surface of the intermediate layer 20 by flowing argon (Ar) and nitrogen (N2) under conditions where the electrical energy applied to the target AlN is relatively small and the vacuum level is relatively low. The target when forming the insulating layer 30 may be Al. 【0026】Next, an electrode 40 is formed on the insulating layer 30. Specifically, first, an adhesion layer to improve adhesion with the insulating layer 30 and a seed layer to improve the bonding strength between the gold film that will become the electrode 40 and the adhesion layer are formed on the surface of the insulating layer 30 as a base for the electrode 40. In this embodiment, the adhesion layer is formed of titanium using sputtering, and the seed layer is formed of palladium (Pd) using sputtering. Next, a gold film that will become the electrode 40 is formed on the seed layer, for example, by electroplating. The gold film may also be formed by sputtering or vapor deposition. Next, after forming the gold film on the seed layer, electrode patterning is performed. Specifically, for example, the gold film is coated with a resist by forming a dry film resist with a laminator, and a resist pattern is formed by exposure and development. Next, using the resist as a mask, the gold film, seed layer, and a part of the adhesion layer are removed by etching, and the resist is peeled off with a stripping solution to form the electrode 40. This process manufactures a semiconductor element mounting substrate 1. However, the manufacturing method of the semiconductor element mounting substrate 1 is not limited to these methods. 【0027】 For example, a substrate for mounting semiconductor devices that incorporate light-emitting diodes (LEDs) has a metal substrate with multiple fins formed on it to efficiently dissipate the heat generated by the LEDs to the outside, thereby increasing heat dissipation efficiency. Therefore, in order to ensure insulation between the electrodes connected to the LEDs and the metal substrate with the multiple fins, it is necessary to place an insulating material between the electrodes and the substrate. 【0028】 Figure 2 is a schematic cross-sectional view of a comparative example semiconductor element mounting substrate C1. The comparative example semiconductor element mounting substrate C1 comprises a heat sink 10, a mounting substrate C30, and electrodes 40. Similar to the semiconductor element mounting substrate 1 of this embodiment, the comparative example semiconductor element mounting substrate C1 supports an optical semiconductor such as a light-emitting diode as a semiconductor element SE via the electrodes 40 and functions as a heat sink substrate that releases heat generated during light emission to the outside. 【0029】The mounting substrate C30 corresponds to the insulating layer 30 provided on the semiconductor element mounting substrate 1 of this embodiment. The mounting substrate C30 is formed of a resin, for example, polyimide. Generally, the thickness of a mounting substrate C30 formed of resin is about 400 μm to 1000 μm, and the thermal conductivity of the resin forming the mounting substrate C30 is, for example, less than 10 W / (m·K), so it tends to act as a barrier to heat conduction between the heat sink 10 and the electrode 40. For this reason, the heat from the semiconductor element SE is not efficiently transferred to the heat sink 10. Furthermore, it is relatively difficult to reduce the thickness of the mounting substrate C30 formed of resin. 【0030】 On the other hand, in the semiconductor element mounting substrate 1 of this embodiment, an insulating layer 30 made of aluminum nitride is placed between the heat sink 10 and the electrode 40 in order to maintain insulation between the heat sink 10 and the electrode 40. As described above, the insulating layer 30 made of aluminum nitride can have a thickness of 10 μm or less, and since the thermal conductivity of aluminum nitride is 50 W / (m·K) or more, it can efficiently transfer heat from the semiconductor element SE to the heat sink 10 while maintaining insulation between the heat sink 10 and the electrode 40, and the semiconductor element mounting substrate 1 can be made smaller. Furthermore, since the insulating layer 30 provided in the semiconductor element mounting substrate 1 of this embodiment is made of ceramic, which has a smaller change in insulating properties with respect to temperature than resins such as polyimide, it is easier to maintain insulating properties even when the temperature changes. 【0031】 As described above, in the semiconductor element mounting substrate 1 of this embodiment, an insulating layer 30 made of ceramic is arranged between the heat sink 10 having the fin portion 11 and the electrode 40. The insulating layer 30 made of ceramic can be made thinner than, for example, a mounting substrate made of polyimide. This makes it possible to reduce the size of the semiconductor element mounting substrate 1 while maintaining the insulation between the heat sink 10 made of metal and the electrode 40. 【0032】Furthermore, in the semiconductor element mounting substrate 1 of this embodiment, the thermal conductivity of the ceramic forming the insulating layer is greater than that of the resin forming the insulating layer. As a result, in the semiconductor element mounting substrate 1 equipped with an insulating layer 30 made of ceramic, the heat of the semiconductor element SE moving via the electrode 40 can be efficiently transferred to the heat sink 10. 【0033】 Furthermore, according to the semiconductor element mounting substrate 1 of this embodiment, the semiconductor element mounting substrate 1 includes an intermediate layer 20 disposed between the heat sink 10 and the insulating layer 30. The intermediate layer 20 can alleviate the stress generated by the difference in thermal expansion between the heat sink 10 and the insulating layer 30, while improving both the bonding strength between the heat sink 10 and the insulating layer 30 and the rigidity of the semiconductor element mounting substrate 1. This makes it possible to suppress the occurrence of defects in the semiconductor element mounting substrate 1. 【0034】 Furthermore, in the semiconductor element mounting substrate 1 of this embodiment, the insulating layer 30 is formed of aluminum nitride, which has a relatively high thermal conductivity. This allows the heat from the semiconductor element SE to be efficiently transferred to the heat sink 10. Therefore, it is possible to suppress the occurrence of malfunctions in the semiconductor element mounting substrate 1 and the semiconductor package on which the semiconductor element SE is mounted due to temperature rise. 【0035】 Furthermore, according to the semiconductor element mounting substrate 1 of this embodiment, the thickness of the insulating layer 30 is 10 μm or less, which can be made thinner than, for example, a mounting substrate made of resin. This makes the semiconductor element mounting substrate 1 even smaller. 【0036】 <Second Embodiment> Figure 3 is a cross-sectional view of the semiconductor element mounting substrate 2 of the second embodiment. Compared with the semiconductor element mounting substrate 1 of the first embodiment (Figure 1), the semiconductor element mounting substrate 2 of the second embodiment has a different size of insulating layer relative to the heat sink. 【0037】The semiconductor element mounting substrate 2 of this embodiment comprises a heat sink 10, an intermediate layer 50, an insulating layer 60, and an electrode 40. Note that, for the sake of explanation, the thickness relationships of the heat sink 10, the intermediate layer 50, the insulating layer 60, and the electrode 40 in Figure 3 are shown differently from the actual thickness relationships. 【0038】 The intermediate layer 50 is positioned between the other main surface 10b of the heat sink 10 and the insulating layer 30. The intermediate layer 50 improves the rigidity of the semiconductor element mounting substrate 2 by bringing the heat sink 10 and the insulating layer 60 into close contact, and also relieves the stress generated by the difference in thermal expansion between the heat sink 10 and the insulating layer 60. Therefore, the intermediate layer 50 suppresses the occurrence of cracks in the insulating layer 60 due to the difference in thermal expansion coefficients between the heat sink 10 and the insulating layer 60. The intermediate layer 50 is made of titanium, similar to the intermediate layer 20 of the first embodiment. As shown in Figure 3, the intermediate layer 50 of this embodiment is formed on a part of the other main surface 10b of the pair of main surfaces 10a and 10b of the heat sink 10. 【0039】 The insulating layer 60 is positioned between the heat sink 10 and the electrode 40, more specifically, between the intermediate layer 50 and the electrode 40. The insulating layer 60 is made of aluminum nitride, similar to the insulating layer 30 in the first embodiment. The thickness of the insulating layer 60 is 1 μm or more and 10 μm or less. In this embodiment, the insulating layer 60 is formed on the entire surface 50a of the intermediate layer 50 opposite to the heat sink 10. 【0040】 Next, the manufacturing method for the semiconductor element mounting substrate 2 of this embodiment will be described. In the manufacturing method for the semiconductor element mounting substrate 2, multiple semiconductor element mounting substrates 2 are manufactured at once. 【0041】Figure 4 is the first diagram illustrating the manufacturing method of the semiconductor element mounting substrate 2 according to this embodiment. In the manufacturing of the semiconductor element mounting substrate 2, first, a member is prepared in which multiple heat sinks 10 are connected. Specifically, multiple fin portions 11 are formed on one of the main surfaces A10a of a flat aluminum member A10. Next, on the aluminum member A10 on which the multiple fin portions 11 are formed, an intermediate layer 50 made of titanium is deposited on the main surface A10b opposite to the main surface A10a on which the multiple fin portions 11 are formed. Multiple intermediate layers 50 are deposited in areas other than the region Sc which includes the cutting allowance for separating the aluminum member A10 into individual pieces, for example, using a mask. Although Figure 4 shows an aluminum member A10 with two heat sinks 10 connected, the number of heat sinks 10 is not limited to this. 【0042】 Next, an insulating layer 60 is formed on each of the multiple intermediate layers 50 that have been formed on the aluminum member A10. The method for forming the insulating layer 60 in this embodiment is the same as the method for forming the insulating layer 30 in the manufacturing method of the semiconductor element mounting substrate 1 of the first embodiment, except that the film is formed using a mask or the like. Next, an electrode 40 is formed on each of the multiple insulating layers 60 in the same manner as the method for forming the electrode 40 in the manufacturing method of the semiconductor element mounting substrate 1 of the first embodiment. 【0043】 Figure 5 is the second diagram illustrating the manufacturing method of the semiconductor element mounting substrate 2 according to this embodiment. In the manufacturing of the semiconductor element mounting substrate 2 according to this embodiment, a plurality of semiconductor element mounting substrates 2 are manufactured by cutting the aluminum member A10 along a region Sc including the cutting allowance, for example, along the cutting line CL shown in Figure 5. 【0044】 As described above, in the semiconductor element mounting substrate 2 of this embodiment, an insulating layer 60 made of ceramic is placed between the heat sink 10 having the fin portion 11 and the electrode 40. The insulating layer 60 made of ceramic can be made thinner than, for example, a mounting substrate made of polyimide. This makes it possible to reduce the size of the semiconductor element mounting substrate 2 while maintaining the insulation between the heat sink 10 and the electrode 40. 【0045】 Further, according to the substrate 2 for mounting a semiconductor element of the present embodiment, the insulating layer 60 is formed on a part of the other main surface 10b of the heat sink 10. Thereby, when manufacturing a semiconductor package by mounting the semiconductor element SE on the substrate 2 for mounting a semiconductor element, the stress generated when mounting the semiconductor element SE on the electrode 40 can be relaxed. Therefore, the occurrence of defects in the semiconductor package can be suppressed. 【0046】 Further, according to the manufacturing method of the substrate 2 for mounting a semiconductor element of the present embodiment, an aluminum member A10 in a state where a plurality of heat sinks 10 are connected is prepared. After forming a plurality of intermediate layers 50, a plurality of insulating layers 60, and a plurality of electrodes 40 on the aluminum member A10, the aluminum member A10 is cut, whereby a plurality of substrates 2 for mounting a semiconductor element can be manufactured at once. 【0047】 <Third Embodiment> FIG. 6 is a cross-sectional view of a substrate 3 for mounting a semiconductor element according to the third embodiment. The substrate 3 for mounting a semiconductor element according to the third embodiment has a different heat sink configuration compared to the substrate 1 for mounting a semiconductor element (FIG. 1) of the first embodiment. 【0048】 The substrate 3 for mounting a semiconductor element of the present embodiment includes a heat sink 70, an intermediate layer 20, an insulating layer 30, and an electrode 40. In FIG. 6, the relationship between the respective thicknesses of the heat sink 70, the intermediate layer 20, the insulating layer 30, and the electrode 40 is illustrated to be different from the actual thickness relationship for convenience of explanation. 【0049】 The heat sink 70 has a pair of main surfaces 10a and 10b. The heat sink 70 of the present embodiment has a fin portion 11 formed of a plurality of irregularities on one of the pair of main surfaces 10a and 10b, and a vapor chamber 72. The heat sink 70 of the present embodiment is made of aluminum. 【0050】The vapor chamber 72 of the heat sink 70 is a hollow member having an internal space 72a and a capillary tube 72b arranged in the internal space 72a. Working fluid is sealed in the internal space 72a. In the vapor chamber 72, the working fluid, which is in liquid state, vaporizes due to the heat of the semiconductor element SE. The vaporized working fluid V moves through the internal space 72a and adheres to the inner wall of the vapor chamber 72 on the fin portion 11 side of the vapor chamber 72. As the heat of the vaporized working fluid V is transferred to the fin portion 11, the working fluid liquefies. The liquefied working fluid W moves along the inner wall of the vapor chamber 72 to the intermediate layer 20 side of the vapor chamber 72. The working fluid W that moves to the intermediate layer 20 side of the vapor chamber 72 passes through the capillary tube 72b and moves close to the semiconductor element SE on the intermediate layer 20 side of the vapor chamber 72, where it vaporizes again due to the heat of the semiconductor element SE. In this embodiment, the heat sink 70 can efficiently transfer heat from the semiconductor element SE to the fin portion 11. 【0051】 As described above, in the semiconductor element mounting substrate 3 of this embodiment, an insulating layer 30 made of ceramic is placed between the heat sink 70 having the fin portion 11 and the electrode 40. The insulating layer 30 made of ceramic can be made thinner than, for example, a mounting substrate made of polyimide. This makes it possible to reduce the size of the semiconductor element mounting substrate 3 while maintaining the insulation between the heat sink 70 and the electrode 40. 【0052】 Furthermore, according to the semiconductor element mounting substrate 3 of this embodiment, the heat sink 70 has a vapor chamber 72 that can efficiently transfer heat from the electrode 40 side to the fin portion 11 side. As a result, the heat of the semiconductor element SE connected to the electrode 40 can be efficiently transferred, thereby improving the heat dissipation performance of the semiconductor element mounting substrate 5. 【0053】 <Fourth Embodiment> Figure 7 is a cross-sectional view of the semiconductor element mounting substrate 4 of the fourth embodiment. The semiconductor element mounting substrate 4 of the fourth embodiment has a different heat sink configuration compared to the semiconductor element mounting substrate 1 of the first embodiment (Figure 1). 【0054】The semiconductor element mounting substrate 4 of this embodiment comprises a heat sink 80, an intermediate layer 20, an insulating layer 30, and an electrode 40. Note that the thickness relationships of the heat sink 80, the intermediate layer 20, the insulating layer 30, and the electrode 40 in Figure 7 are illustrated differently from the actual thickness relationships for the sake of explanation. 【0055】 The heat sink 80 has a pair of main surfaces 10a and 10b. The heat sink 80 of this embodiment has a plate-like portion 81 having the other main surface 10b of the pair of main surfaces 10a and 10b, and a fin portion 82 consisting of a plurality of protrusions and recesses on one of the main surfaces 10a of the pair of main surfaces 10a and 10b. 【0056】 The plate-like portion 81 is a plate-shaped part made of aluminum. The other main surface 10b of the plate-like portion 81 is joined to the insulating layer 30 via the intermediate layer 20. 【0057】 The fin portion 82 is positioned on the plate-shaped portion 81 on the side opposite to the other main surface 10b. At least a part of the fin portion 82 is a mesh member. Specifically, as shown in Figure 7, the fin portion 82 of this embodiment has a plurality of columnar portions 82a, and all of the columnar portions 82a are mesh members. As a result, the surface area of ​​the fin portion 82 is larger than, for example, if the plurality of columnar portions were solid members. Therefore, it is easier for the fin portion 82 to come into contact with a fluid such as air flowing between the plurality of columnar portions 82a, thereby improving the heat dissipation performance of the heat sink 80. 【0058】 As described above, in the semiconductor element mounting substrate 4 of this embodiment, an insulating layer 30 made of ceramic is placed between the heat sink 80 having the fin portion 82 and the electrode 40. The insulating layer 30 made of ceramic can be made thinner than, for example, a mounting substrate made of polyimide. This makes it possible to reduce the size of the semiconductor element mounting substrate 4 while maintaining the insulation between the heat sink 80 and the electrode 40. 【0059】Furthermore, according to the semiconductor element mounting substrate 4 of this embodiment, at least a portion of the fin portion 82 of the heat sink 80 is made of mesh material, and the contact area with the fluid flowing between the multiple columnar portions 82a that form multiple irregularities is relatively large. As a result, heat from the semiconductor element SE connected to the electrode 40 can be efficiently released via the heat sink 80. 【0060】 <Fifth Embodiment> Figure 8 is a cross-sectional view of the semiconductor element mounting substrate 5 of the fifth embodiment. The semiconductor element mounting substrate 5 of the fifth embodiment differs from the semiconductor element mounting substrate 1 of the first embodiment (Figure 1) in the configuration of the heat sink. 【0061】 The semiconductor element mounting substrate 5 of this embodiment comprises a heat sink 90, an intermediate layer 20, an insulating layer 30, and an electrode 40. Note that the thickness relationships of the heat sink 90, the intermediate layer 20, the insulating layer 30, and the electrode 40 in Figure 8 are illustrated differently from the actual thickness relationships for the sake of explanation. 【0062】 The heat sink 90 has a pair of main surfaces 10a and 10b, and includes a plate-like portion 91 having the other main surface 10b of the pair of main surfaces 10a and 10b, and a fin portion 92 consisting of a plurality of protrusions and recesses on one of the main surfaces 10a of the pair of main surfaces 10a and 10b. 【0063】 The plate-like portion 91 is a plate-shaped part made of aluminum. The other main surface 10b of the plate-like portion 91 is connected to the insulating layer 30 via the intermediate layer 20. 【0064】 The fin portion 92 is positioned on the plate-like portion 91 on the opposite side from the insulating layer 30, and each of its tip surfaces 92a has a plurality of columnar portions 92b that form one of the main surfaces 10a. In this embodiment, the material forming the plate-like portion 91 and the material forming the columnar portions 92b are different. The plurality of columnar portions 92b are joined to the plate-like portion 91 on the opposite side from the insulating layer 30. Therefore, it is desirable that the joining surface 91a to which the columnar portions 92b of the plate-like portion 91 are joined be formed relatively roughly in order to improve the joining force. 【0065】Figure 9 is a cross-sectional view of a first modified example of the semiconductor element mounting substrate 5 of this embodiment. The fin portion 92 of the heat sink 90 provided on the semiconductor element mounting substrate 5 shown in Figure 9 has two types of columnar portions 92b and 92c. In the semiconductor element mounting substrate 5 shown in Figure 9, the height of the columnar portions is made different depending on the location. Specifically, the columnar portion 92c located near the central axis CA5 of the semiconductor element mounting substrate 5 is formed to be lower than the columnar portion 92b which is relatively far from the central axis CA5 of the semiconductor element mounting substrate 5. 【0066】 Figure 10 is a cross-sectional view of a second modified example of the semiconductor element mounting substrate 5 of this embodiment. The fin portion 92 of the heat sink 90 provided on the semiconductor element mounting substrate 5 shown in Figure 10 has two types of columnar portions 92b and 92d. In the semiconductor element mounting substrate 5 shown in Figure 10, the thickness of the columnar portions is made different depending on the location. Specifically, the columnar portion 92d located near the central axis CA5 of the semiconductor element mounting substrate 5 is formed to be thinner than the columnar portion 92b which is relatively far from the central axis CA5 of the semiconductor element mounting substrate 5. This makes it possible to change the volume of the columnar portions and the size of the tip surface of the columnar portions. 【0067】 As described above, in the semiconductor element mounting substrate 5 of this embodiment, an insulating layer 30 made of ceramic is placed between the heat sink 90 having the fin portion 92 and the electrode 40. The insulating layer 30 made of ceramic can be made thinner than, for example, a mounting substrate made of polyimide. This makes it possible to reduce the size of the semiconductor element mounting substrate 5 while maintaining the insulation between the heat sink 90 and the electrode 40. 【0068】Furthermore, according to the semiconductor element mounting substrate 5 of this embodiment, the fin portion 92 has a tip surface 92a which has a plurality of columnar portions 92b, 92c, and 92d that form one of the main surfaces 10a of the heat sink 90. ​​Since the heat sink 90 is formed by joining the plurality of columnar portions 92b, 92c, and 92d to the plate-shaped portion 91, the length of the columnar portions and the size of the tip surface can be changed. This allows the design of the heat sink 90 to be modified so that the heat of the semiconductor element SE connected to the electrode 40 can be efficiently released. Therefore, the heat dissipation performance of the semiconductor element mounting substrate 5 can be improved. 【0069】 Furthermore, in the semiconductor element mounting substrate 5 of this embodiment, the material forming the plate-shaped portion 91 and the material forming the columnar portions 92b, 92c, and 92d are different. This makes it possible to adjust the weight of the heat sink 90 without reducing the heat dissipation performance of the heat sink 90. 【0070】 <Modifications of this Embodiment> The present invention is not limited to the above-described embodiments, and can be implemented in various forms without departing from the spirit of the invention. For example, the following modifications are also possible. 【0071】 [Modification 1] In the above embodiment, the semiconductor element mounting substrate comprises a heat sink, an intermediate layer, an insulating layer, and electrodes. The semiconductor element mounting substrate may also comprise other films or layers. Furthermore, the insulating layer and the intermediate layer may be formed from multiple films. 【0072】 [Modification 2] In the above embodiment, the semiconductor element mounting substrate is provided with an intermediate layer between the heat sink and the insulating layer. The intermediate layer is not required, but by providing it, the rigidity of the semiconductor element mounting substrate is improved and the stress generated by the difference in thermal expansion between the heat sink and the insulating layer can be alleviated, thereby suppressing the occurrence of cracks in the insulating layer due to the difference in thermal expansion coefficients between the heat sink and the insulating layer. 【0073】[Modification 3] In the above embodiment, the insulating layer was assumed to be formed of amorphous aluminum nitride. The material forming the insulating layer is not limited to this. The insulating layer may also be formed of crystalline aluminum nitride. 【0074】 [Modification 4] In the above embodiment, the thickness of the insulating layer was set to 10 μm or less. The thickness of the insulating layer may be greater than 10 μm, but the smaller the thickness of the insulating layer, the better the thermal conductivity between the heat sink and the electrode can be improved. 【0075】 [Modification 5] In the above embodiment, the semiconductor element SE mounted on the semiconductor element mounting substrate was described as a light-emitting diode or a semiconductor laser, but it is not limited to these. It may also be a power semiconductor or the like, which generates a relatively large amount of heat. 【0076】 [Modification 6] In the fifth embodiment, all of the columnar portions 82a of the fin portion 82 were made of mesh material. Not all of the columnar portions of the fin portion are made of mesh material. At least some of the columnar portions of the fin portion are made of mesh material, or all of them are made of solid material. 【0077】 [Modification 7] In the sixth embodiment, the material forming the plate-shaped portion 91 and the material forming the columnar portion 92b were different. In the semiconductor element mounting substrate 5 of the sixth embodiment, the material forming the plate-shaped portion 91 and the material forming the columnar portion 92b do not have to be different. 【0078】 [Modification 8] In the sixth embodiment, as shown in Figure 9, the height of the columnar portion is varied depending on the location, and as shown in Figure 10, the thickness of the columnar portion is varied depending on the location. The relationship of the shapes of the multiple columnar portions is not limited to these. For example, both the height and thickness may be varied depending on the location. 【0079】The embodiments of this specification have been described above based on the embodiments and modifications described above. The embodiments described above are for the purpose of facilitating understanding of this specification and do not limit it. This specification may be modified and improved without departing from its spirit and the scope of the claims, and equivalents thereof are included in this specification. Furthermore, any technical features that are not described as essential in this specification may be deleted as appropriate. 【0080】<Application Example 1> A semiconductor element mounting substrate comprising: a heat sink having a pair of main surfaces and made of metal, wherein one of the pair of main surfaces has a fin portion consisting of a plurality of irregularities; an electrode disposed on the other main surface side of the pair of main surfaces of the heat sink and connected to a semiconductor element; and an insulating layer disposed between the other main surface of the heat sink and the electrode, the insulating layer being made of ceramic. <Application Example 2> The semiconductor element mounting substrate according to Application Example 1, further comprising an intermediate layer disposed between the other main surface of the heat sink and the insulating layer. <Application Example 3> The semiconductor element mounting substrate according to Application Example 1 or Application Example 2, wherein the insulating layer is made of aluminum nitride. <Application Example 4> The semiconductor element mounting substrate according to any one of Application Examples 1 to 3, wherein the thickness of the insulating layer is 10 μm or less. <Application Example 5> A semiconductor element mounting substrate according to any one of Application Examples 1 to 4, wherein the heat sink has a vapor chamber. <Application Example 6> A semiconductor element mounting substrate according to any one of Application Examples 1 to 5, wherein at least a part of the fin portion is a mesh member. <Application Example 7> A semiconductor element mounting substrate according to any one of Application Examples 1 to 6, wherein the heat sink has a plate-like portion having the other main surface, and the fin portion is arranged on the plate-like portion on the opposite side from the insulating layer, and has a plurality of columnar portions whose tip surfaces form the one main surface. <Application Example 8> A semiconductor element mounting substrate according to Application Example 7, wherein the material forming the plate-like portion and the material forming the columnar portions are different. 【0081】1, 2, 3, 4, 5... Substrate for mounting semiconductor elements SE... Semiconductor element 10, 70, 80, 90... Heat sink 10a, 10b... Pair of main surfaces (of the heat sink) 10a... One main surface (of the heat sink) 10b... The other main surface (of the heat sink) 11, 82, 92... Fin section 82a, 92b, 92c, 92d... Columnar section 20, 50... Intermediate layer 30, 60... Insulating layer 40... Electrode 72... Vapor chamber 81, 91... Plate-shaped section 92a... Tip surface (of the columnar section)

Claims

1. A substrate for mounting a semiconductor element, comprising: a heat sink having a pair of main surfaces and made of metal, wherein one of the pair of main surfaces has a fin portion consisting of a plurality of irregularities; an electrode disposed on the other main surface of the pair of main surfaces of the heat sink and connected to a semiconductor element; and an insulating layer disposed between the other main surface of the heat sink and the electrode, the insulating layer being made of ceramic.

2. The semiconductor element mounting substrate according to claim 1 is further characterized by comprising an intermediate layer disposed between the other main surface of the heat sink and the insulating layer.

3. A semiconductor element mounting substrate according to claim 1 or claim 2, wherein the insulating layer is formed of aluminum nitride.

4. A semiconductor element mounting substrate according to claim 3, characterized in that the thickness of the insulating layer is 10 μm or less.

5. A semiconductor element mounting substrate according to claim 1 or claim 2, wherein the heat sink has a vapor chamber.

6. A semiconductor element mounting substrate according to claim 1 or claim 2, characterized in that at least a portion of the fin portion is a mesh member.

7. A semiconductor element mounting substrate according to claim 1 or claim 2, wherein the heat sink comprises a plate-like portion having the other main surface, and the fin portion is arranged on the plate-like portion on the side opposite to the insulating layer, and has a plurality of columnar portions whose tip surfaces form the one main surface.

8. A semiconductor element mounting substrate according to claim 7, characterized in that the material forming the plate-shaped portion and the material forming the columnar portion are different.

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