阅读说明：本技术 半导体元件接合用基板、半导体装置及电力转换装置 (Substrate for bonding semiconductor element, semiconductor device, and power conversion device ) 是由 石川悟 于 2017-06-02 设计创作，主要内容包括：本发明的目的在于提供一种对通过焊料将半导体元件接合于基板时的缩孔的产生进行抑制,并且使半导体元件的散热性提高的半导体元件接合用基板、半导体装置及电力转换装置。本发明所涉及的半导体元件接合用基板(100)具备绝缘板(1)和与绝缘板(1)的主面接合的金属图案(2),金属图案(2)的与绝缘板(1)相反侧的主面(6)具备供半导体元件(4)通过焊料(5)进行接合的接合区域(6a),金属图案(2)具备配置于主面(6)的至少一个凹坑(7),至少一个凹坑(7)在接合区域(6a)内与接合区域(6a)的中央部分相比配置为更靠近接合区域(6a)的边缘。(The invention aims to provide a substrate for bonding a semiconductor element, a semiconductor device and a power conversion device, which can inhibit the generation of shrinkage cavity when the semiconductor element is bonded to the substrate by solder and improve the heat dissipation of the semiconductor element. A semiconductor element bonding substrate (100) according to the present invention comprises an insulating plate (1) and a metal pattern (2) bonded to a main surface of the insulating plate (1), wherein a main surface (6) of the metal pattern (2) on the opposite side of the insulating plate (1) comprises a bonding region (6a) to which a semiconductor element (4) is bonded by solder (5), the metal pattern (2) comprises at least one recess (7) disposed in the main surface (6), and the at least one recess (7) is disposed in the bonding region (6a) closer to the edge of the bonding region (6a) than to the central portion of the bonding region (6 a).)

1. A substrate (100) for bonding a semiconductor element, comprising:

an insulating plate (1); and

a metal pattern (2) bonded to the main surface of the insulating plate (1),

the main surface (6) of the metal pattern (2) on the side opposite to the insulating plate (1) is provided with a bonding region (6a) to which a semiconductor element (4) is bonded by solder (5),

the metal pattern (2) comprises at least one recess (7) arranged in the main surface (6),

the at least one indentation (7) is arranged within the joining area (6a) closer to an edge of the joining area (6a) than to a central portion of the joining area (6 a).

2. The substrate (100) for bonding a semiconductor element according to claim 1,

said at least one pit (7) comprising a plurality of pits (7),

the plurality of dimples (7) are arranged along the edge of the bonding region (6 a).

3. The substrate (200) for bonding a semiconductor element according to claim 1,

the at least one recess (7) is a continuous groove (8) arranged along the edge of the joining area (6 a).

4. The substrate (300) for bonding a semiconductor element according to claim 2,

further comprises metal members (9) respectively disposed in the plurality of recesses (7),

the metal member (9) has a thermal conductivity greater than that of the solder (5).

5. The substrate (400) for bonding semiconductor elements according to claim 3,

further comprising a metal member (10) disposed in the groove (8),

the metal member (10) has a thermal conductivity greater than that of the solder (5).

6. The substrate (100, 200, 300, 400) for bonding semiconductor elements according to any one of claims 1 to 5,

a plating layer is formed on the surface of the bonding region (6a) of the metal pattern (2).

7. A semiconductor device (101, 201, 301, 401) is provided with:

the substrate (100, 200, 300, 400) for semiconductor element bonding according to any one of claims 1 to 6; and

and a semiconductor element (4) bonded to the bonding region (6a) of the metal pattern (2) by solder (5).

8. The semiconductor device (101, 201, 301, 401) of claim 7,

the semiconductor element (4) includes a power semiconductor including SiC or GaN.

9. A power conversion device (800) is provided with:

a power conversion circuit (801) that converts input power and outputs the converted power; and

a control circuit (802) that outputs a control signal to the power conversion circuit,

the power conversion circuit (801) is provided with at least one semiconductor device (101, 201, 301, 401) according to claim 7 or 8.

10. A substrate (500) for bonding a semiconductor element, comprising:

an insulating plate (1); and

a metal pattern (2) bonded to the main surface of the insulating plate (1),

the main surface (6) of the metal pattern (2) on the side opposite to the insulating plate (1) is provided with a bonding region (6a) to which a semiconductor element (4) is bonded by solder (5),

in the bonding region (6a), the main surface (6) of the metal pattern (2) has a different height between a central portion of the bonding region (6a) and the periphery of the central portion.

11. The substrate (500) for bonding a semiconductor element according to claim 10,

within the joining region (6a), the central portion of the joining region (6a) is lower than the periphery of the central portion.

12. The substrate (600) for bonding a semiconductor element according to claim 11,

a metal member (12) is disposed in the central portion of the joining region (6a),

the metal member (12) has a thermal conductivity smaller than that of the solder (5).

13. The substrate (700) for bonding semiconductor elements according to claim 10,

within the joining region (6a), the central portion of the joining region (6a) is higher than the periphery of the central portion.

14. The substrate (500, 600, 700) for bonding semiconductor elements according to any one of claims 10 to 13,

a plating layer is formed on the surface of the bonding region (6a) of the metal pattern (2).

15. A semiconductor device (501, 601, 701) is provided with:

the substrate (500, 600, 700) for semiconductor element bonding according to any one of claims 10 to 14; and

and a semiconductor element (4) bonded to the bonding region (6a) of the metal pattern (2) by solder (5).

16. The semiconductor device (501, 601, 701) of claim 15,

the semiconductor element (4) includes a power semiconductor including SiC or GaN.

17. A power conversion device (800) is provided with:

a power conversion circuit (801) that converts input power and outputs the converted power; and

a control circuit (802) that outputs a control signal to the power conversion circuit,

the power conversion circuit (801) includes at least one semiconductor device (501, 601, 701) according to claim 15 or 16.

Technical Field

The invention relates to a substrate for bonding a semiconductor element, a semiconductor device, and a power conversion device.

Background

In order to ensure high reliability, an amorphous solder mainly composed of any of Sn-Cu, Sn-Ag, Sn-Sb, Sn-In, and Sn-Bi is used as a solder for bonding a semiconductor element and an insulating substrate. These solders have a problem that solder shrinkage cavities are easily generated.

In recent years, development of semiconductor devices that operate even at high temperatures has been actively carried out, and miniaturization, high withstand voltage, and high current density of semiconductor devices have been advanced. In particular, wide band gap semiconductors such as SiC and GaN have a larger band gap than Si semiconductors, and high withstand voltage, miniaturization, high current density, and high temperature operation of semiconductor devices are expected (for example, see patent document 1). However, if solder shrinkage occurs directly below the semiconductor element, heat dissipation when the semiconductor element generates heat is reduced, resulting in a reduction in characteristics. Therefore, it is necessary to suppress the occurrence of solder shrinkage and ensure stable operation of the semiconductor device.

Patent document 1: japanese patent laid-open publication No. 2005-260181

Disclosure of Invention

A planar metal pattern for soldering a semiconductor element is formed on a surface of an insulating substrate of a conventional semiconductor device. When a semiconductor element is soldered to a metal pattern, shrinkage tends to occur in the solidified solder. If solder shrinkage occurs directly below the end of the semiconductor element, the heat dissipation of the semiconductor element is reduced, which causes a reduction in the electrical characteristics and thermal resistance of the semiconductor element. Therefore, the solder must be re-melted to correct the shrinkage cavity or discarded, which causes a reduction in productivity.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a substrate for bonding a semiconductor element, a semiconductor device, and a power conversion device, in which the occurrence of shrinkage cavities is suppressed when the semiconductor element is bonded to the substrate with solder, and the heat dissipation of the semiconductor element is improved.

The substrate for bonding a semiconductor element according to the present invention includes: an insulating plate; and a metal pattern bonded to the main surface of the insulating plate, wherein the main surface of the metal pattern on the opposite side of the insulating plate has a bonding region to which the semiconductor element is bonded by solder, and the metal pattern has at least one recess disposed in the main surface, and the at least one recess is disposed closer to an edge of the bonding region than a central portion of the bonding region in the bonding region.

The substrate for bonding a semiconductor element according to the present invention includes: an insulating plate; and a metal pattern bonded to the main surface of the insulating plate, wherein the main surface of the metal pattern on the opposite side of the insulating plate has a bonding region to which the semiconductor element is bonded by solder, and the main surface of the metal pattern has a different height in the bonding region between the central portion and the periphery of the central portion of the bonding region.

ADVANTAGEOUS EFFECTS OF INVENTION

In the semiconductor element bonding substrate according to the present invention, the recesses are provided in the vicinity of the edge of the bonding region on the main surface of the metal pattern. When the semiconductor element is soldered to the bonding area, solder is supplied to the inside of the recess. When the molten solder solidifies, the solder filled in the recess shrinks, and thus the shrinkage of the fillet portion of the solder is alleviated. This can suppress the occurrence of a shrinkage cavity in the fillet portion of the solder, and the shrinkage cavity can enter the lower portion of the semiconductor element. The heat dissipation of the semiconductor device can be improved by suppressing the occurrence of shrinkage cavities in the solder.

According to the semiconductor element bonding substrate of the present invention, the main surfaces of the metal patterns are made different in height from each other in the central portion and the periphery of the central portion of the bonding region, whereby the solidification timing of the solder can be made different in the central portion and the periphery of the central portion of the bonding region. For example, by making the central portion of the bonding region 6a lower than the periphery of the central portion, solder is supplied to the recessed portion in the center of the bonding region, and the solder filling the recessed portion increases the heat capacity directly below the central portion of the semiconductor element. This can solidify the solder from the edge of the bonding region first. That is, since the central portion of the bonding region is the final solidification point of the solder, the occurrence of shrinkage cavities can be suppressed at the fillet portion that is solidified early. In addition, for example, by making the central portion of the bonding region higher than the periphery of the central portion, more solder is supplied to the periphery of the central portion than the central portion of the bonding region. Therefore, when the molten solder solidifies, the solder around the central portion of the bonding region contracts, and thus the contraction of the fillet portion of the solder is alleviated. This can suppress the occurrence of shrinkage cavities in the fillet portion of the solder. The heat dissipation of the semiconductor device can be improved by suppressing the occurrence of shrinkage cavities in the solder.

The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

Drawings

Fig. 1 is a plan view of a semiconductor element bonding substrate according to embodiment 1.

Fig. 2 is a sectional view of the semiconductor device according to embodiment 1.

Fig. 3 is a plan view of the substrate for bonding a semiconductor element according to embodiment 2.

Fig. 4 is a sectional view of the semiconductor device according to embodiment 2.

Fig. 5 is a plan view of the substrate for bonding a semiconductor element according to embodiment 3.

Fig. 6 is a sectional view of the semiconductor device according to embodiment 3.

Fig. 7 is a plan view of the substrate for bonding a semiconductor element according to embodiment 4.

Fig. 8 is a sectional view of the semiconductor device according to embodiment 4.

Fig. 9 is a plan view of the substrate for bonding a semiconductor element according to embodiment 5.

Fig. 10 is a sectional view of a semiconductor device according to embodiment 5.

Fig. 11 is a plan view of the substrate for bonding a semiconductor element according to embodiment 6.

Fig. 12 is a sectional view of a semiconductor device according to embodiment 6.

Fig. 13 is a plan view of the substrate for bonding a semiconductor element according to embodiment 7.

Fig. 14 is a sectional view of a semiconductor device according to embodiment 7.

Fig. 15 is a diagram showing a configuration of a power converter according to embodiment 8.

Detailed Description

< embodiment 1 >

Fig. 1 is a plan view of a semiconductor element bonding substrate 100 according to embodiment 1. Fig. 2 is a sectional view of the semiconductor device 101 according to embodiment 1. In the semiconductor device 101 shown in fig. 2, the semiconductor element 4 is bonded to the bonding region 6a of the semiconductor element bonding substrate 100 by the solder 5. The cross section of the semiconductor device 101 shown in fig. 2 corresponds to a cross section along the line a-a of fig. 1.

The substrate 100 for bonding a semiconductor element includes an insulating plate 1 and a metal pattern 2. The metal pattern 2 is bonded to the main surface of the insulating plate 1. The main surface 6 of the metal pattern 2 on the opposite side to the insulating plate 1 includes a bonding region 6a to which the semiconductor element 4 is bonded by the solder 5. A plurality of recesses 7 are formed in the bonding region 6a of the main surface 6 of the metal pattern 2. The plurality of dimples 7 are arranged closer to the edge of the joining region 6a than the center portion of the joining region 6a in the joining region 6 a. As shown in fig. 2, pits 7 are formed in a portion of the metal pattern 2 located directly below the end portion of the semiconductor element 4.

In addition, although a plurality of dimples 7 are formed in fig. 1, the effect of suppressing the occurrence of sink marks described later can be obtained by forming at least one dimple 7.

In order to bond metal pattern 2 and semiconductor element 1 more favorably, a plating layer may be formed on main surface 6 of metal pattern 2. As shown in fig. 2, the rear metal pattern 3 may be bonded to the surface of the insulating plate 1 opposite to the metal pattern 2.

The semiconductor element 4 is a power semiconductor element including, for example, a SiC semiconductor. The semiconductor element 4 is, for example, an igbt (insulated gate bipolar transistor), a MOSFET (metal-oxide-semiconductor field-effect transistor), or the like.

< Effect >

The semiconductor element bonding substrate 100 according to embodiment 1 includes an insulating plate 1 and a metal pattern 2 bonded to a main surface of the insulating plate 1, a main surface 6 of the metal pattern 2 on the opposite side of the insulating plate 1 includes a bonding region 6a to which a semiconductor element 4 is bonded with solder 5, the metal pattern 2 includes at least one dimple 7 disposed on the main surface 6, and the at least one dimple 7 is disposed closer to an edge of the bonding region 6a than a central portion of the bonding region 6a in the bonding region 6 a.

In the substrate 100 for bonding a semiconductor element according to embodiment 1, the recesses 7 are provided in the vicinity of the edge of the bonding region 6a on the main surface 6 of the metal pattern 2. When the semiconductor element 4 is soldered to the bonding area 6a, solder is supplied into the recess 7. When molten solder 5 solidifies, solder 5 filled in recess 7 contracts, and thus the contraction of fillet portion 5a of solder 5 is alleviated. This can suppress the occurrence of a shrinkage cavity in fillet portion 5a of solder 5, and the shrinkage cavity can enter the lower portion of semiconductor element 4. By suppressing the occurrence of shrinkage of the solder 5, the heat dissipation performance of the semiconductor device 101 can be improved.

In the substrate 100 for bonding a semiconductor element according to embodiment 1, at least one pit includes a plurality of pits 7, and the plurality of pits 7 are arranged along the edge of the bonding region 6 a. Therefore, by disposing the plurality of dimples 7 along the edge of the bonding region 6a, the occurrence of sink holes can be suppressed at the outer periphery of the solder 5 bonding the semiconductor element 4.

< embodiment 2 >

Fig. 3 is a plan view of the substrate 200 for bonding a semiconductor element according to embodiment 2. Fig. 4 is a cross-sectional view of the semiconductor device 201 according to embodiment 2. In the semiconductor device 201 shown in fig. 4, the semiconductor element 4 is bonded to the bonding region 6a of the substrate 200 for bonding semiconductor elements with the solder 5. The cross section of the semiconductor device 201 shown in fig. 4 corresponds to a cross section along the line B-B of fig. 3.

The substrate 200 for bonding a semiconductor element includes an insulating plate 1 and a metal pattern 2. The metal pattern 2 is bonded to the main surface of the insulating plate 1. The main surface 6 of the metal pattern 2 on the opposite side to the insulating plate 1 includes a bonding region 6a to which the semiconductor element 4 is bonded by the solder 5. A continuous groove 8 is formed in the bonding region 6a of the main surface of the metal pattern 2. A continuous groove 8 is arranged within the joining region 6a along the edge of the joining region 6 a. As shown in fig. 4, a continuous groove 8 is formed in a portion of the metal pattern 2 located directly below the end portion of the semiconductor element 4.

In order to bond metal pattern 2 and semiconductor element 1 more favorably, a plating layer may be formed on main surface 6 of metal pattern 2. As shown in fig. 4, the rear metal pattern 3 may be bonded to the surface of the insulating plate 1 opposite to the metal pattern 2.

< Effect >

In the substrate 200 for bonding a semiconductor element according to embodiment 2, the dimples 7 described in embodiment 1 are continuous grooves 8 arranged along the edge of the bonding region 6 a. Therefore, by arranging the continuous groove 8 along the edge of the bonding region 6a, more solder 5 can be supplied into the groove 8 than in the case where the dimples 7 are provided as in embodiment 1. This can more effectively suppress the occurrence of a crater in fillet portion 5a of solder 5, and the crater can enter the lower portion of semiconductor element 4.

< embodiment 3 >

Fig. 5 is a plan view of the substrate 300 for bonding a semiconductor element according to embodiment 3. Fig. 6 is a cross-sectional view of a semiconductor device 301 according to embodiment 3. In the semiconductor device 301 shown in fig. 6, the semiconductor element 4 is bonded to the bonding region 6a of the substrate 300 for bonding a semiconductor element with the solder 5 interposed therebetween. The cross section of the semiconductor device 301 shown in fig. 6 corresponds to a cross section along the line C-C of fig. 5.

The substrate 300 for bonding a semiconductor element further includes metal members 9 disposed in the recesses 7, respectively, compared to the substrate 100 for bonding a semiconductor element (fig. 1) of embodiment 1. The metal member 9 is formed of a material having a higher thermal conductivity than the solder 5. The metal member 9 is spherical in shape. Examples of the metal member 9 include Cu, Ni, Au, Ag, Ni-plated Cu, and Ni-plated Al. The structure of the semiconductor element bonding substrate 300 other than the metal member 9 is the same as that of the semiconductor element bonding substrate 100 (fig. 1), and therefore, the description thereof is omitted.

< Effect >

The semiconductor element bonding substrate 300 according to embodiment 3 further includes metal members 9, the metal members 9 are respectively disposed in the plurality of recesses 7 of the semiconductor element bonding substrate 100 according to embodiment 1, and the thermal conductivity of the metal members 9 is higher than that of the solder 5.

In the substrate 300 for bonding a semiconductor element according to embodiment 3, the recesses 7 are provided in the vicinity of the edge of the bonding region 6a on the main surface 6 of the metal pattern 2, and the metal members 9 are disposed in the recesses 7. When the semiconductor element 4 is soldered to the bonding region 6a and the molten solder 5 is solidified, the solder 5 can be solidified from the edge of the bonding region 6a where the metal member 9 having high thermal conductivity is arranged. That is, since the central portion of the bonding region 6a is the final solidification point of the solder 5, the occurrence of shrinkage cavities can be suppressed in the early solidified fillet portion 5 a. By suppressing the occurrence of shrinkage of the solder 5, the heat dissipation performance of the semiconductor device 301 can be improved.

< embodiment 4 >

Fig. 7 is a plan view of the substrate 400 for bonding a semiconductor element according to embodiment 4. Fig. 8 is a cross-sectional view of the semiconductor device 401 according to embodiment 4. In the semiconductor device 401 shown in fig. 8, the semiconductor element 4 is bonded to the bonding region 6a of the substrate 400 for bonding a semiconductor element by the solder 5. The cross section of the semiconductor device 301 shown in fig. 8 corresponds to a cross section along the line D-D of fig. 7.

The semiconductor element bonding substrate 400 further includes a metal member 10 disposed in the groove 8, as compared with the semiconductor element bonding substrate 200 (fig. 3) according to embodiment 2. The metal member 10 is formed of a material having a higher thermal conductivity than the solder 5. The metal member 10 has a frame shape. The metal member 10 is, for example, Cu, Ni, Au, Ag, Ni-plated Cu, or Ni-plated Al. The structure of the substrate 400 for bonding a semiconductor element, excluding the metal member 10, is the same as that of the substrate 200 for bonding a semiconductor element (fig. 3), and therefore, the description thereof is omitted.

< Effect >

The semiconductor element bonding substrate 400 according to embodiment 4 further includes the metal member 10, the metal member 10 is disposed in the groove 8 of the semiconductor element bonding substrate 200 according to embodiment 2, and the thermal conductivity of the metal member 10 is larger than that of the solder 5.

In the substrate 400 for bonding a semiconductor element according to embodiment 4, the continuous groove 8 is provided along the edge of the bonding region 6a on the main surface 6 of the metal pattern 2, and the metal member 10 is disposed in the groove 8. When the semiconductor element 4 is soldered to the bonding region 6a and the molten solder 5 is solidified, the solder 5 can be solidified from the edge of the bonding region 6a where the metal member 10 having high thermal conductivity is arranged. That is, since the central portion of the bonding region 6a is the final solidification point of the solder 5, the occurrence of shrinkage cavities can be suppressed in the early solidified fillet portion 5 a. By suppressing the occurrence of shrinkage of the solder 5, the heat dissipation performance of the semiconductor device 401 can be improved.

< embodiment 5 >

Fig. 9 is a plan view of the substrate 500 for bonding a semiconductor element according to embodiment 5. Fig. 10 is a sectional view of a semiconductor device 501 according to embodiment 5. In the semiconductor device 501 shown in fig. 10, the semiconductor element 4 is bonded to the bonding region 6a of the substrate 500 for bonding a semiconductor element by the solder 5. The cross section of the semiconductor device 501 shown in fig. 10 corresponds to a cross section along the line E-E of fig. 9.

The substrate 500 for bonding a semiconductor element includes an insulating plate 1 and a metal pattern 2. The metal pattern 2 is bonded to the main surface of the insulating plate 1. The main surface 6 of the metal pattern 2 on the opposite side to the insulating plate 1 includes a bonding region 6a to which the semiconductor element 4 is bonded by the solder 5.

In the bonding region 6a of the main surface 6 of the metal pattern 2, the height of the main surface 6 of the metal pattern 2 is different between the central portion and the periphery of the central portion of the bonding region 6 a. In embodiment 5, as shown in fig. 10, a recess 11 is formed in the main surface 6 of the metal pattern 2 such that the central portion of the bonding region 6a is lower than the periphery of the central portion.

In order to bond metal pattern 2 and semiconductor element 1 more favorably, a plating layer may be formed on main surface 6 of metal pattern 2. As shown in fig. 10, the rear metal pattern 3 may be bonded to the surface of the insulating plate 1 opposite to the metal pattern 2.

< Effect >

The semiconductor element bonding substrate 500 according to embodiment 5 includes an insulating plate 1 and a metal pattern 2 bonded to a main surface of the insulating plate 1, a main surface 6 of the metal pattern 2 on the opposite side of the insulating plate 1 includes a bonding region 6a to which the semiconductor element 4 is bonded with solder 5, and the main surface 6 of the metal pattern 2 is different in height between a central portion and a periphery of the central portion of the bonding region 6a in the bonding region 6 a.

According to the substrate 500 for bonding a semiconductor element of embodiment 5, the height of the main surface 6 of the metal pattern 2 is made different between the central portion and the periphery of the central portion of the bonding region 6a, so that the solidification timing of the solder 5 can be made different between the central portion and the periphery of the central portion of the bonding region 6 a. For example, by making the central portion of the bonding region 6a lower than the periphery of the central portion, the solder 5 can be solidified earlier around the central portion of the bonding region 6a as described below.

In the bonding region 6a of the substrate 500 for bonding a semiconductor element according to embodiment 5, the central portion of the bonding region 6a is lower than the periphery of the central portion. When the semiconductor element 4 is soldered to the bonding region 6a and the molten solder 5 is solidified, the solder 5 is supplied to the concave portion 11 in the center of the bonding region 6a, and the solder 5 filling the concave portion 11 increases the heat capacity directly below the center portion of the semiconductor element 4. This can solidify the solder 5 from the edge of the bonding region 6a first. That is, since the central portion of the bonding region 6a is the final solidification point of the solder 5, the occurrence of shrinkage cavities can be suppressed in the early solidified fillet portion 5 a. By suppressing the occurrence of shrinkage of the solder 5, the heat dissipation performance of the semiconductor device 501 can be improved.

< embodiment 6 >

Fig. 11 is a plan view of the substrate 600 for bonding a semiconductor element according to embodiment 6. Fig. 12 is a sectional view of the semiconductor device 601 according to embodiment 6. In the semiconductor device 601 shown in fig. 12, the semiconductor element 4 is bonded to the bonding region 6a of the substrate 600 for bonding a semiconductor element by the solder 5. The cross section of the semiconductor device 601 shown in fig. 12 corresponds to a cross section along the line F-F in fig. 11.

The substrate 600 for bonding a semiconductor element further includes a metal member 12 with respect to the substrate 500 for bonding a semiconductor element (fig. 9) of embodiment 5, and the metal member 12 is disposed in the recess 11 in the central portion of the bonding region 6 a. The metal member 12 is formed of a material having a smaller thermal conductivity than the solder 5. The metal member 12 is, for example, an alloy mainly containing Ni. The structure of the substrate 600 for bonding a semiconductor element, except for the metal member 12, is the same as that of the substrate 500 for bonding a semiconductor element (fig. 9), and therefore, the description thereof is omitted.

< Effect >

In the substrate 600 for bonding a semiconductor element according to embodiment 6, the metal member 12 is disposed in the recess 11 in the central portion of the bonding region 6a, and the thermal conductivity of the metal member 12 is lower than that of the solder 5.

By embedding the metal member 12 having low thermal conductivity in the central portion of the bonding region 6a where the semiconductor element 4 is bonded, the heat capacity immediately below the central portion of the semiconductor element 4 increases when the semiconductor element 4 is soldered to the bonding region 6a and the molten solder 5 solidifies. This can solidify the solder 5 from the edge of the bonding region 6a first. That is, since the central portion of the bonding region 6a is the final solidification point of the solder 5, the occurrence of shrinkage cavities can be suppressed in the early solidified fillet portion 5 a. By suppressing the occurrence of shrinkage of the solder 5, the heat dissipation performance of the semiconductor device 601 can be improved.

< embodiment 7 >

Fig. 13 is a plan view of the substrate 700 for bonding a semiconductor element according to embodiment 7. Fig. 14 is a cross-sectional view of the semiconductor device 701 according to embodiment 7. In the semiconductor device 701 shown in fig. 14, the semiconductor element 4 is bonded to the bonding region 6a of the substrate for bonding semiconductor elements 700 with the solder 5. The cross section of the semiconductor device 701 shown in fig. 14 corresponds to a cross section along a line E-E of fig. 13.

The substrate 700 for bonding a semiconductor element includes an insulating plate 1 and a metal pattern 2. The metal pattern 2 is bonded to the main surface of the insulating plate 1. The main surface 6 of the metal pattern 2 on the opposite side to the insulating plate 1 includes a bonding region 6a to which the semiconductor element 4 is bonded by the solder 5.

In the bonding region 6a of the main surface 6 of the metal pattern 2, the height of the main surface 6 of the metal pattern 2 is different between the central portion and the periphery of the central portion of the bonding region 6 a. In embodiment 7, as shown in fig. 14, a convex portion 13 is formed on the main surface 6 of the metal pattern 2 so that the central portion of the bonding region 6a is higher than the periphery of the central portion.

In order to bond metal pattern 2 and semiconductor element 1 more favorably, a plating layer may be formed on main surface 6 of metal pattern 2. As shown in fig. 14, the rear metal pattern 3 may be bonded to the surface of the insulating plate 1 opposite to the metal pattern 2.

< Effect >

In the substrate 700 for bonding a semiconductor element according to embodiment 7, the central portion of the bonding region 6a is higher than the periphery of the central portion in the bonding region 6 a. When the semiconductor element 4 is soldered to the bonding area 6a, more solder 5 is supplied to the periphery of the central portion than to the central portion of the bonding area 6 a. Therefore, when the molten solder 5 solidifies, the solder 5 around the central portion of the bonding region 6a contracts, and thus the contraction of the fillet portion 5a of the solder 5 is alleviated. This can suppress the occurrence of a shrinkage cavity in fillet portion 5a of solder 5, and the shrinkage cavity can enter the lower portion of semiconductor element 4. By suppressing the occurrence of shrinkage of the solder 5, the heat dissipation performance of the semiconductor device 701 can be improved.

In the semiconductor element bonding substrates 100, 200, 300, 400, 500, 600, and 700 described in embodiments 1 to 7, a plating layer may be formed on the surface of the bonding region 6a of the metal pattern 2. By forming a thin film of Ni, for example, on the surface of the bonding region 6a of the metal pattern 2, bonding by the solder 5 can be performed more favorably.

In each of the semiconductor devices 101, 201, 301, 401, 501, 601, and 701 described in embodiments 1 to 7, the semiconductor element 4 includes a power semiconductor including SiC or GaN. A switching element that processes a large current and a high voltage and is turned on and off at a high speed, such as for power conversion, is particularly required to have high heat dissipation. The semiconductor device of the present invention is particularly effective when it has a structure in which the semiconductor device includes a power semiconductor including SiC or GaN.

< embodiment 8 >

In embodiment 8, the semiconductor devices 101, 201, 301, 401, 501, 601, and 701 according to any one of embodiments 1 to 7 are applied to a power conversion device. A power conversion apparatus 800 of a three-phase inverter will be described as an example of the power conversion apparatus.

Fig. 15 is a diagram showing a configuration of a power conversion system according to embodiment 8. The power conversion apparatus 800 shown in fig. 15 is connected to a power source 901 and a load 902. Power supply 901 is a dc power supply and supplies dc power to power conversion device 800. The power supply 901 can be configured by various power supplies, for example, a dc system, a solar cell, a storage battery, or the like. The power supply 901 may be a rectifier circuit connected to an AC system, an AC/DC converter, or the like. The power supply 901 may be a DC/DC converter that converts DC power output from the DC system into predetermined power.

The power conversion apparatus 800 is a three-phase inverter connected between a power source 901 and a load 902. The power converter 800 converts dc power supplied from the power supply 901 into ac power, and supplies the ac power to the load 902. As shown in fig. 15, the power conversion device 800 includes a power conversion circuit 801 and a control circuit 802. The control circuit 802 outputs a control signal for controlling the on/off operation of the power conversion circuit 801 to the power conversion circuit 801. The power conversion circuit 801 converts dc power into ac power and outputs the ac power based on the control signal.

The power conversion circuit 801 is, for example, a 2-level three-phase full bridge circuit. For example, two semiconductor devices 101 connected in series correspond to the U-phase, the V-phase, and the W-phase, respectively. In this case, the power conversion circuit 801 includes six semiconductor devices 101 in total. The semiconductor device 101 may be any of the semiconductor devices 201, 301, 401, 501, 601, and 701.

Load 902 is a three-phase motor driven by ac power supplied from power conversion device 800. The load 902 is not limited to a specific application, and is a motor mounted on various electrical devices. The load 902 is, for example, a motor for a hybrid car, an electric car, a railway vehicle, an elevator, and an air conditioner.

The power conversion circuit 801 is a three-phase full bridge circuit, but is not limited to this, and any circuit may be used as long as it includes at least one of the semiconductor devices 101, 201, 301, 401, 501, 601, and 701 and converts power.

< Effect >

The power conversion device 800 of embodiment 8 includes: a power conversion circuit 801 that converts input power and outputs the converted power; and a control circuit 802 that outputs a control signal to the power conversion circuit 801, and the power conversion circuit 801 includes at least one of the semiconductor devices 101, 201, 301, 401, 501, 601, and 701.

As described in embodiments 1 to 7, the semiconductor devices 101, 201, 301, 401, 501, 601, and 701 can suppress the occurrence of shrinkage cavities in the solder 5 and improve heat dissipation. Therefore, the heat dissipation of the power conversion device 800 including the semiconductor device can be improved.

In addition, the present invention can freely combine the respective embodiments, or appropriately modify or omit the respective embodiments within the scope of the invention. Although the present invention has been described in detail, the above description is only exemplary in all aspects, and the present invention is not limited thereto. It is understood that numerous modifications not illustrated can be devised without departing from the scope of the invention.

Description of the reference numerals

1 insulating plate, 2 metal pattern, 3 back metal pattern, 4 semiconductor element, 5 solder, 5a solder foot, 6 main surface, 7 pit, 8 groove, 9, 10, 12 metal component, 11 concave part, 13 convex part, 100, 200, 300, 400, 500, 600, 700 semiconductor element bonding substrate, 101, 201, 301, 401, 501, 601, 701 semiconductor device, 800 power conversion device, 801 power conversion circuit, 802 control circuit, 901 power supply, 902 load.