Substrate for mounting semiconductor devices

Abstract

This invention provides a technology for reducing warping of semiconductor device mounting substrates. [Solution] The substrate for mounting semiconductor elements comprises a base material, electrodes connected to the semiconductor elements, and an insulating layer disposed between the base material and the electrodes, the insulating layer having a first insulating film and a second insulating film having different Young's moduli.

Description

Technical Field

[0008] , , , ,

[0007]

[0001] The present invention relates to a substrate for mounting semiconductor elements.

[0002] Conventionally, a substrate for mounting semiconductor elements having electrodes connected to semiconductor elements has been known (for example, Patent Document 1).

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, even with the prior art such as Patent Document 1, there is still room for improvement in the technology for reducing the warpage of the substrate for mounting semiconductor elements in the substrate for mounting semiconductor elements.

[0005] An object of the present invention is to provide a technology for reducing the warpage of a substrate for mounting semiconductor elements in the substrate for mounting semiconductor elements.

Means for Solving the Problems

[0006] The present invention has been made to solve at least a part of the above - mentioned problems and can be realized in the following forms.

[0007] (1) According to one aspect of the present invention, a substrate for mounting semiconductor elements is provided. This substrate for mounting semiconductor elements includes a base material, an electrode connected to a semiconductor element, and an insulating layer disposed between the base material and the electrode, the insulating layer having a first insulating film and a second insulating film with different Young's moduli.

[0008] In this configuration, the insulating layer placed between the substrate and the electrode has a first insulating film and a second insulating film with different Young's moduli. In the insulating layer, the insulating film with the higher Young's moduli of the two insulating films maintains the insulation between the substrate and the electrode. On the other hand, the insulating film with the lower Young's moduli of the two insulating films experiences relatively low stress, so the substrate for mounting semiconductor devices is less likely to warp than, for example, when the Young's moduli of the entire insulating layer is relatively high. In this way, the insulating layer can reduce stress while maintaining insulation, thus reducing the warping of the substrate for mounting semiconductor devices.

[0009] (2) In the semiconductor device mounting substrate of the above configuration, the first insulating film and the second insulating film may have the same composition. With this configuration, since the first insulating film and the second insulating film of the insulating layer have the same composition, when forming the insulating layer in the manufacturing of the semiconductor device mounting substrate, the material used when forming the first insulating film and the material used when forming the second insulating film are basically the same. As a result, the time required to switch materials when forming the insulating layer is eliminated, and the time required to form the insulating layer can be shortened. Therefore, the production efficiency of the semiconductor device mounting substrate can be improved.

[0010] (3) In the semiconductor element mounting substrate of the above configuration, the Young's modulus of the first insulating film is greater than that of the second insulating film, and the first insulating film may be positioned closer to the substrate than the second insulating film in the insulating layer. With this configuration, the second insulating film, which has a relatively small Young's modulus, is positioned further from the substrate than the first insulating film in the insulating layer. This makes it possible to maintain the overall thickness of the insulating layer while reducing the warping of the semiconductor element mounting substrate.

[0011] (4) In the semiconductor element mounting substrate of the above configuration, the Young's modulus of the first insulating film is greater than that of the second insulating film, and the second insulating film may be positioned on the substrate side of the insulating layer than the first insulating film. With this configuration, the second insulating film, which has a relatively small Young's modulus, is positioned between the first insulating film and the substrate. This makes it possible to mitigate thermal stress, for example, so that thermal stress generated in the substrate due to temperature changes during the manufacturing of the semiconductor element mounting substrate is not transmitted to the first insulating film, which has a relatively large Young's modulus. This makes it possible to reduce warping of the semiconductor element mounting substrate while suppressing damage to the insulating layer.

[0012] (5) In the semiconductor element mounting substrate of the above configuration, the first insulating film and the second insulating film may be formed of silicon nitride. With this configuration, the first insulating film and the second insulating film are formed of silicon nitride, which has a relatively low Young's modulus. This makes it possible to further reduce the warping of the semiconductor element mounting substrate.

[0013] Furthermore, the present invention can be realized in various forms, for example, in the form of a substrate having an insulating layer, a product including a substrate for mounting semiconductor elements, a semiconductor package including a substrate for mounting semiconductor elements, a method for manufacturing the substrate for mounting semiconductor elements and the semiconductor package. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic cross-sectional view of a semiconductor element mounting substrate according to the first embodiment. [Figure 2] This is a diagram illustrating the testing method for evaluation tests. [Figure 3] This diagram illustrates the results of the first evaluation test. [Figure 4] This diagram illustrates the results of the second evaluation test. [Figure 5] This is a schematic cross-sectional view of a semiconductor element mounting substrate according to the second embodiment. [Figure 6] This is a schematic cross-sectional view of a semiconductor element mounting substrate according to the third embodiment. [Modes for carrying out the invention]

[0015] <First Embodiment> Figure 1 is a schematic cross-sectional view of a semiconductor element mounting substrate 1 according to the first embodiment. In this embodiment, the semiconductor element mounting substrate 1 supports optical semiconductors such as light-emitting diodes (LEDs) and semiconductor lasers (LDs) as semiconductor elements 5 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 base material 10, an adhesion layer 20, an insulating layer 30, and electrodes 40. Note that the thickness relationships of the base material 10, adhesion layer 20, insulating layer 30, and electrodes 40 in Figure 1 are shown differently from the actual thickness relationships for the sake of explanation.

[0016] The base material 10 is a flat plate-shaped component that serves as the base for the semiconductor element mounting substrate 1. In this embodiment, the thickness of the base material 10 is, for example, 1 mm. The base material 10 is made of metal. In this embodiment, the base material 10 is made of copper (Cu). The base material 10 may be formed from a material mainly composed of copper, aluminum (Al), or a material mainly composed of aluminum. Here, "main component" refers to a component that accounts for more than 50% by mass in the material in question. The base material 10 may be made of an alloy of copper and aluminum. By forming the base material 10 from these metals, the heat generated in the semiconductor element 5 can be efficiently released to the outside through the base material 10.

[0017] The adhesion layer 20 is disposed between the base material 10 and the insulating layer 30. In the present embodiment, the adhesion layer 20 is made of titanium (Ti). The thickness of the adhesion layer 20 is, for example, 0.5 μm. The adhesion layer 20 adheres the base material 10 and the insulating layer 30, and suppresses the occurrence of cracks in the insulating layer 30 due to the difference in the thermal expansion coefficients of the base material 10 and the insulating layer 30. The material for forming the adhesion layer 20 is not limited to titanium, and may be chromium (Cr), molybdenum (Mo), copper, etc. that have adhesion to the insulating layer. In addition, it is desirable that the material for forming the adhesion layer 20 has a value of the thermal expansion coefficient between the value of the thermal expansion coefficient of the material forming the base material 10 and the value of the thermal expansion coefficient of the material forming the insulating layer 30.

[0018] The insulating layer 30 is disposed between the base material 10 and the electrode 40, and more specifically, between the adhesion layer 20 and the electrode 40. The insulating layer 30 has a first insulating film 31 and a second insulating film 32 with different Young's moduli. In the present embodiment, the Young's modulus of the first insulating film 31 is smaller than the Young's modulus of the second insulating film 32. The Young's modulus of each of the first insulating film 31 and the second insulating film 32 is obtained by converting the measurement result of the Vickers hardness measured using a nanoindenter into the Young's modulus. In the present embodiment, the first insulating film 31 and the second insulating film 32 are laminated, and the first insulating film 31 having a relatively small Young's modulus is disposed closer to the base material 10 than the second insulating film 32.

[0019] The first insulating film 31 and the second insulating film 32 have the same composition and are both formed of silicon nitride (SiN). The first insulating film 31 is a so-called sparse film, and the second insulating film 32 is a so-called dense film. The insulating layer 30 insulates the base material 10 and the electrode 40. The material for forming the insulating layer 30 is not limited to silicon nitride, and may be aluminum nitride (AlN).

[0020] The electrode 40 is disposed on the surface of the base material 10 of the insulating layer 30 on the side opposite thereto. The electrode 40 is connected to the semiconductor element 5. 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 of the mounted semiconductor element 5. Note that the material forming the electrode 40 is not limited to gold and may be made of copper.

[0021] Next, a method for manufacturing the semiconductor element mounting substrate 1 of the present embodiment will be described. In manufacturing the semiconductor element mounting substrate 1, first, pretreatment of the member to be the base material 10 is performed. Specifically, plate-shaped rolled copper is prepared. After mirror-polishing the surface of the prepared rolled copper, nickel or the like having resistance to a gold etching solution is plated on the mirror-polished surface. Thereby, the produced base material 10 is less likely to be oxidized and has improved corrosion resistance. A adhesion layer 20 formed of titanium is formed on the surface of the produced base material 10. The adhesion layer 20 is formed by chemical vapor deposition (CVD) or physical vapor deposition (PVD). Note that, regarding the surface treatment of the prepared rolled copper, chemical polishing may be used instead of mirror polishing.

[0022] Next, an insulating layer 30 is formed on the adhesion layer 20. In the method for manufacturing the semiconductor element mounting substrate 1 of the present embodiment, the insulating layer 30 is formed by RF sputtering. The insulating layer 30 uses a target of silicon (Si) or silicon nitride, and is formed on the surface of the base material 10 by flowing argon (Ar) and nitrogen (N2) at a vacuum degree of 0.1 to 1.0 Pa while maintaining the temperature of the base material 10 at 100 to 300°C. In forming the insulating layer 30 of the present embodiment, the insulation property of the insulating layer 30 is ensured by changing the RF bias applied to the base material 10. Specifically, the RF bias when forming the first insulating film 31 having a relatively small Young's modulus is made smaller than the RF bias when forming the second insulating film 32 having a relatively large Young's modulus. For example, no RF bias is applied when forming the first insulating film 31, and an RF bias greater than 0 (V) is applied when forming the second insulating film 32.

[0023] 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 31 of the insulating layer 30 as a base for the electrode 40. In this embodiment, the adhesion layer is formed from titanium using sputtering, and the seed layer is formed from 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 device mounting substrate 1. However, the manufacturing method of the semiconductor device mounting substrate 1 is not limited to these methods.

[0024] Next, two evaluation tests relating to the semiconductor device mounting substrate 1 of this embodiment will be described. In these evaluation tests, the effect of RF bias in the process of forming the insulating layer was evaluated. Specifically, a sample for the evaluation test was prepared using a method similar to the manufacturing method of the semiconductor device mounting substrate 1 described above. At this time, multiple samples with insulating layers having different deposition conditions were prepared by changing the RF bias applied to the substrate during the deposition of the insulating layer by RF sputtering. For the multiple samples prepared, the relationship between RF bias and electrical resistivity was evaluated in the first evaluation test. In the second evaluation test, the relationship between RF bias and insulation yield was evaluated. In each sample, multiple electrodes with a square shape of 1.5 mm on each side and multiple electrodes with a square shape of 5 mm on each side were formed and evaluated.

[0025] Figure 2 illustrates the test method for the evaluation test. In this evaluation test, the electrical resistivity of the sample was measured using the two-terminal method. As shown in Figure 2, sample S consists of a substrate 10s, an electrode 401s with a square shape of 1.5 mm on each side, and an electrode 405s with a square shape of 5 mm on each side. In this evaluation test, electrodes Eb, E1, and E5 were placed on the substrate 10s and electrodes 401s and 405s, respectively, and the voltage between electrode Eb and electrode E1, the voltage between electrode Eb and electrode E5, and the leakage current of sample S were measured. The electrical resistivity was determined from the measured voltage, leakage current, and electrode area of ​​each electrode (first evaluation test). In addition, insulation tests were performed on each of the multiple electrodes 401s and 405s, and electrodes with an electrical resistance of 10 MΩ or more when 100 V was applied were considered acceptable, and the insulation yield for each electrode area was calculated (second evaluation test). Note that Figure 2 shows, for convenience, a state in which electrical resistivity is measured with electrodes 401s and 405s each formed on a single sample.

[0026] Figure 3 illustrates the results of the first evaluation test. Figure 3 shows the relationship between RF bias and electrical resistivity. Figure 3 shows the electrical resistivity of four types of samples, depending on the magnitude of the RF bias applied to the substrate when forming the insulating layer: "no RF bias," "RF bias power 50W," "RF bias power 100W," and "RF bias power 150W." Note that the electrical resistivity data shown in Figure 3 represents the average value of the electrical resistivity of each of the multiple electrodes, which have a square shape with sides of 5 mm.

[0027] As shown in Figure 3, it was confirmed that the electrical resistivity increased when an RF bias was applied. Therefore, it was confirmed that applying an RF bias to the substrate during the deposition of the insulating layer improved the insulating properties of the insulating layer.

[0028] Figure 4 illustrates the results of the second evaluation test. Figure 4 shows the relationship between RF bias and insulation yield. Similar to Figure 3, Figure 4 shows the insulation yield for four types of samples, depending on the magnitude of the RF bias applied to the substrate when forming the insulating layer: "no RF bias," "RF bias power 50W," "RF bias power 100W," and "RF bias power 150W." The insulation yield data shown in Figure 4 is for electrodes with a square shape of 1.5 mm on each side and electrodes with a square shape of 5 mm on each side.

[0029] As shown in Figure 4, it was confirmed that applying an RF bias improved the insulation yield. In particular, for electrodes with a square shape with sides of 5 mm (data shown as dot hatches in Figure 4), which have a relatively large area and therefore many current paths, the insulation yield for the sample without RF bias was 0%, while the sample with RF bias applied had an insulation yield of at least 60%. Therefore, the data shown in Figure 4 also confirms that applying an RF bias to the substrate during the deposition of the insulating layer improves the insulation performance of the entire insulating layer in the sample.

[0030] When an RF bias is applied to the substrate during the deposition of the insulating layer, the insulating layer becomes a so-called dense film, improving its insulating properties as shown in Figures 3 and 4. However, a dense film has high hardness and therefore a high Young's modulus. As a result, the film's stress tends to increase. On the other hand, when an RF bias is not applied to the substrate during the deposition of the insulating layer, the insulating layer becomes a so-called sparse film. This reduces hardness and thus the Young's modulus, making it less likely for the film's stress to increase. Therefore, by having both a dense and a sparse insulating layer, the overall stress of the insulating layer is reduced, and the overall stress of the semiconductor device mounting substrate is also reduced, thus reducing the warping of the semiconductor device mounting substrate.

[0031] As described above, the semiconductor element mounting substrate 1 of this embodiment has an insulating layer 30 disposed between the base material 10 and the electrode 40, which comprises a first insulating film 31 and a second insulating film 32 having different Young's moduli. In the insulating layer 30, the second insulating film 32, which has a relatively large Young's moduli, maintains insulation between the base material 10 and the electrode 40. On the other hand, the first insulating film 31, which has a relatively small Young's moduli, experiences relatively low stress, so the semiconductor element mounting substrate 1 is less prone to warping than, for example, the case where the Young's moduli of the entire insulating layer is relatively large. In this way, the insulating layer 30 can reduce stress while maintaining insulation, thereby reducing warping of the semiconductor element mounting substrate 1.

[0032] Furthermore, in the semiconductor device mounting substrate 1 of this embodiment, since both the first insulating film 31 and the second insulating film 32 of the insulating layer 30 are formed of silicon nitride, when the insulating layer 30 is formed during the manufacturing of the semiconductor device mounting substrate 1, the material used when forming the first insulating film 31 and the material used when forming the second insulating film 32 are basically the same. As a result, the time required to switch materials when forming the insulating layer 30 is eliminated, and the time required to form the insulating layer 30 can be shortened. Therefore, the production efficiency of the semiconductor device mounting substrate 1 can be improved.

[0033] Furthermore, in the semiconductor element mounting substrate 1 of this embodiment, the first insulating film 31, which has a relatively small Young's modulus, is positioned so as to be sandwiched between the second insulating film 32 and the base material 10. This allows for the mitigation of thermal stress, for example, that is generated in the base material 10 due to temperature changes during the manufacturing of the semiconductor element mounting substrate 1, so as not to be transmitted to the second insulating film 32, which has a relatively large Young's modulus. This reduces warping of the semiconductor element mounting substrate 1 while suppressing damage to the insulating layer 30.

[0034] Furthermore, in the semiconductor element mounting substrate 1 of this embodiment, the first insulating film 31 and the second insulating film 32 are formed of silicon nitride, which has a relatively low Young's modulus. This makes it possible to further reduce the warping of the semiconductor element mounting substrate 1 while suppressing damage to the insulating layer 30.

[0035] <Second Embodiment> Figure 5 is a cross-sectional view of the semiconductor element mounting substrate 2 of the second embodiment. The semiconductor element mounting substrate 2 of the second embodiment has a different insulating layer configuration compared to the semiconductor element mounting substrate 1 of the first embodiment (Figure 1).

[0036] The semiconductor element mounting substrate 2 of the second embodiment comprises a base material 10, an adhesion layer 20, an insulating layer 50, and an electrode 40. Note that the thickness relationships of the base material 10, adhesion layer 20, insulating layer 50, and electrode 40 in Figure 5 are illustrated differently from the actual thickness relationships for the sake of explanation.

[0037] The insulating layer 50 is positioned between the adhesion layer 20 formed on the substrate 10 and the electrode 40. The insulating layer 50 has a first insulating film 51 and a second insulating film 52, each having a different Young's modulus. The Young's modulus of the first insulating film 51 is greater than that of the second insulating film 52. In this embodiment, the first insulating film 51 is formed of aluminum nitride, and the second insulating film 52 is formed of silicon nitride. In the insulating layer 50, the first insulating film 51 is positioned closer to the substrate 10 than the second insulating film 52. The insulating layer 50 insulates the substrate 10 from the electrode 40. Note that the relationship between the materials forming the first insulating film 51 and the second insulating film 52 is not limited to this. For example, the first insulating film 51 may be formed of silicon nitride, and the second insulating film 52 may be formed of aluminum nitride.

[0038] Next, the manufacturing method for the semiconductor element mounting substrate 2 of this embodiment will be described. The manufacturing method for the semiconductor element mounting substrate 2 is similar to the manufacturing method for the semiconductor element mounting substrate 1 of the first embodiment, but the method of forming the insulating layer is different. Here, we will explain the parts of the manufacturing method for the semiconductor element mounting substrate 2 that differ from the manufacturing method for the semiconductor element mounting substrate 1.

[0039] In the manufacturing of the semiconductor device mounting substrate 2, when depositing an insulating layer 50 on the adhesion layer 20, the target in reactive sputtering is changed. Specifically, when depositing the insulating layer 50 on the adhesion layer 20, first, the target is aluminum (Al) and a first insulating film 51 is deposited. After depositing the first insulating film 51, the target is changed to silicon and a second insulating film 52 is deposited. As a result, an insulating layer 50 consisting of the first insulating film 51 and the second insulating film 52 is deposited. In the deposition of the insulating layer 50 in this embodiment, the insulating properties of the insulating layer 50 are ensured by changing the vacuum level in reactive sputtering.

[0040] As described above, in the semiconductor element mounting substrate 2 of this embodiment, the insulating layer 50 has a first insulating film 51 with a relatively high Young's modulus that maintains insulating properties, while a second insulating film 52 with a relatively low Young's modulus reduces the overall stress of the insulating layer. This makes it possible to reduce the warping of the semiconductor element mounting substrate 2.

[0041] Furthermore, in the semiconductor element mounting substrate 2 of this embodiment, the second insulating film 52, which has a relatively small Young's modulus, is positioned further away from the substrate 10 than the first insulating film 51 in the insulating layer 50. This makes it possible to maintain the thickness of the insulating layer 50 while reducing the warping of the semiconductor element mounting substrate 2.

[0042] <Third Embodiment> Figure 6 is a cross-sectional view of the semiconductor element mounting substrate 3 of the third embodiment. The semiconductor element mounting substrate 3 of the third embodiment has a different insulating layer configuration compared to the semiconductor element mounting substrate 1 of the first embodiment (Figure 1).

[0043] The semiconductor element mounting substrate 3 of the third embodiment comprises a base material 10, an adhesion layer 20, an insulating layer 60, and an electrode 40. Note that the thickness relationships of the base material 10, adhesion layer 20, insulating layer 60, and electrode 40 in Figure 6 are illustrated differently from the actual thickness relationships for the sake of explanation.

[0044] The insulating layer 60 is positioned between the adhesion layer 20 formed on the substrate 10 and the electrode 40. The insulating layer 60 has a first insulating film 61 and a second insulating film 62, each having a different Young's modulus. The Young's modulus of the first insulating film 61 is greater than that of the second insulating film 62. In this embodiment, the first insulating film 61 is formed of aluminum nitride, and the second insulating film 62 is formed of silicon nitride. In this embodiment, the second insulating film 62 is positioned on the substrate 10 side of the insulating layer 60 than the first insulating film 61. The insulating layer 60 insulates the substrate 10 from the electrode 40. Note that the relationship between the materials forming the first insulating film 61 and the second insulating film 62 is not limited to this. For example, the first insulating film 61 may be formed of silicon nitride, and the second insulating film 62 may be formed of aluminum nitride.

[0045] Next, the manufacturing method of the semiconductor element mounting substrate 3 of this embodiment will be described. The manufacturing method of the semiconductor element mounting substrate 3 is similar to the manufacturing method of the semiconductor element mounting substrate 1 of the first embodiment, but the method of forming the insulating layer is different. Here, we will explain the parts of the manufacturing method of the semiconductor element mounting substrate 3 that differ from the manufacturing method of the semiconductor element mounting substrate 1.

[0046] In the manufacturing of the semiconductor device mounting substrate 3, when depositing an insulating layer 60 on the adhesion layer 20, the target in reactive sputtering is changed. Specifically, when depositing the insulating layer 60 on the adhesion layer 20, first, a second insulating film 62 is deposited using silicon as the target. After depositing the second insulating film 62, the target is changed to aluminum, and a first insulating film 61 is deposited. As a result, an insulating layer 60 consisting of the first insulating film 61 and the second insulating film 62 is deposited. In the deposition of the insulating layer 60 in this embodiment, the insulating properties of the insulating layer 60 are ensured by changing the vacuum level in reactive sputtering.

[0047] As described above, in the semiconductor element mounting substrate 3 of this embodiment, the insulating layer 60 has a first insulating film 61 with a relatively high Young's modulus that maintains insulating properties, while a second insulating film 61 with a relatively low Young's modulus reduces the overall stress of the insulating layer. This makes it possible to reduce the warping of the semiconductor element mounting substrate 3.

[0048] Furthermore, in the semiconductor element mounting substrate 3 of this embodiment, the first insulating film 61, which has a relatively small Young's modulus, is positioned so as to be sandwiched between the second insulating film 61 and the base material 10. This allows thermal stress generated in the base material 10 to be mitigated so that it is not transmitted to the second insulating film 62, which has a relatively large Young's modulus. As a result, warping of the semiconductor element mounting substrate 3 can be reduced while suppressing damage to the insulating layer 60.

[0049] <Modified form of this embodiment> The present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from its spirit, for example, the following modifications are also possible.

[0050] [Example 1] In the first embodiment, it was assumed that the Young's modulus of an insulating layer having multiple insulating films of the same composition could be changed by the RF bias during film deposition of the insulating layer. However, the method for changing the Young's modulus when the composition is the same is not limited to this. For example, it can also be adjusted by changing the vacuum level in reactive sputtering. Specifically, lowering the vacuum level relatively results in a so-called dense film with high insulating properties, while increasing the vacuum level relatively results in a so-called sparse film with low insulating properties, but the Young's modulus decreases, thus reducing stress. Therefore, by changing the vacuum level during film deposition of each of the multiple insulating films included in the insulating layer, the Young's modulus can be changed while maintaining insulating properties.

[0051] [Differentiation 2] In the first embodiment, the insulating layer 30 has a first insulating film 31 and a second insulating film 32 having different Young's moduli. The Young's moduli in the insulating layer may change continuously in the lamination direction between the substrate and the insulating layer. Such an insulating layer can be formed, for example, by continuously changing the RF bias applied to the substrate when forming the insulating layer.

[0052] [Difference 3] In the first embodiment, the insulating layer 30 was configured such that the first insulating film 31, which has a relatively small Young's modulus, was positioned closer to the substrate 10 than the second insulating film 32, which has a larger Young's modulus than the first insulating film 31. However, the second insulating film 32 may also be positioned closer to the substrate 10 than the first insulating film 31.

[0053] [Differentiation Example 4] In the second and third embodiments, the Young's modulus was adjusted by changing the target during the deposition of the insulating layer to obtain a different composition. In addition to changing the composition, the RF bias may be changed, as in the first embodiment, or the degree of vacuum may be changed to further adjust the Young's modulus.

[0054] [Difference 5] In the above-described embodiment, the semiconductor element 5 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.

[0055] [Modification 6] In the embodiments described above, the insulating layer was assumed to have a first insulating film and a second insulating film having different Young's moduli. However, the configuration of the insulating layer is not limited to these. The insulating layer may also have other films besides the first insulating film and the second insulating film. That is, the insulating layer may be formed by laminating three or more films, including the first insulating film and the second insulating film.

[0056] 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.

[0057] (Application Example 1) A substrate for mounting semiconductor devices, Substrate and semiconductor element cross-electrode, An insulating layer disposed between the substrate and the electrode, comprising an insulating layer having a first insulating film and a second insulating film having different Young's moduli, characterized in that A substrate for mounting semiconductor devices. (Application Example 2) A semiconductor element mounting substrate as described in Application Example 1, The first insulating film and the second insulating film are characterized by having the same composition. A substrate for mounting semiconductor devices. (Application Example 3) A semiconductor element mounting substrate as described in Application Example 1 or Application Example 2, The Young's modulus of the first insulating film is greater than that of the second insulating film. The first insulating film is characterized in that, in the insulating layer, it is positioned closer to the substrate than the second insulating film. A substrate for mounting semiconductor devices. (Application Example 4) A semiconductor element mounting substrate as described in any one of Application Examples 1 to 3, The Young's modulus of the first insulating film is greater than that of the second insulating film. The second insulating film is characterized in that, in the insulating layer, it is positioned closer to the substrate than the first insulating film. A substrate for mounting semiconductor devices. (Application Example 5) A semiconductor element mounting substrate as described in any one of Application Examples 1 to 4, The first insulating film and the second insulating film are characterized by being formed of silicon nitride. A substrate for mounting semiconductor devices. [Explanation of symbols]

[0058] 1, 2, 3… Substrates for mounting semiconductor devices 10...Base material 30, 50, 60…insulating layer 40...electrode 31, 51, 61… First insulating film 32, 52, 62… Second insulating film

Claims

1. A substrate for mounting semiconductor devices, Substrate and semiconductor element cross-electrode, An insulating layer disposed between the substrate and the electrode, comprising an insulating layer having a first insulating film and a second insulating film having different Young's moduli, A substrate for mounting semiconductor devices.

2. A semiconductor element mounting substrate according to claim 1, The first insulating film and the second insulating film are characterized by having the same composition. A substrate for mounting semiconductor devices.

3. A substrate for mounting semiconductor elements according to claim 1 or claim 2, The Young's modulus of the first insulating film is greater than that of the second insulating film. The first insulating film is characterized in that, in the insulating layer, it is positioned closer to the substrate than the second insulating film. A substrate for mounting semiconductor devices.

4. A substrate for mounting semiconductor elements according to claim 1 or claim 2, The Young's modulus of the first insulating film is greater than that of the second insulating film. The second insulating film is characterized in that, in the insulating layer, it is positioned closer to the substrate than the first insulating film. A substrate for mounting semiconductor devices.

5. A substrate for mounting semiconductor elements according to claim 1 or claim 2, The first insulating film and the second insulating film are characterized by being formed of silicon nitride. A substrate for mounting semiconductor devices.

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