joint

Abstract

This suppresses the increase in pressure caused by angularity. [Solution] A joint comprising a first member, a second member, and a sintered layer formed by sintering a metal paste applied between the first member and the second member, wherein either the first member or the second member has a protruding portion that projects toward the other member, the protruding portion has a protruding surface that projects most toward the other member, and the sintered layer is formed on the protruding surface and the region surrounding the protruding surface.

Description

Technical Field

[0001] The present invention relates to a joined body.

Background Art

[0002] In Patent Document 1, there is a member connection method for connecting a first member and a second member with a copper sintered body, including a printing step of forming a coating film of a copper paste for connection in a predetermined printing pattern in a connection region between the first member and the second member, a lamination step of laminating the first member and the second member through the coating film, and a sintering step of forming the copper sintered body that connects the first member and the second member by sintering the coating film. The printing pattern formed in the printing step consists of a coating film formation region where the coating film is formed and a coating film non-formation region where the coating film is not formed. At least one end of the coating film non-formation region is connected outside the connection region, and in the printing step, after the lamination step, the printing pattern is formed so that the whole or a part of the coating film non-formation region remains as a void.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The end of the applied sintering paste is pulled by a mask or a nozzle and becomes angular. If there is an angular part in the sintering paste, it becomes difficult to apply pressure uniformly, and joining failure is likely to occur. In order to apply pressure uniformly, the pressure must be increased more than when there is no angular part. For example, when there are many coating film non-formation regions as in the technology described in Patent Document 1, these problems are likely to occur. An object of the present invention is to suppress an increase in the pressure caused by angularity. [Means for solving the problem]

[0005] The joint to which the present invention applies comprises a first member, a second member, and a sintered layer formed by sintering a metal paste applied between the first member and the second member, wherein either the first member or the second member has a protruding portion that projects toward the other member, the protruding portion has a protruding surface that projects most toward the other member, and the sintered layer is formed on the protruding surface and the region surrounding the protruding surface. Here, the protruding portion may have an inclined portion around the protruding surface that is inclined in a direction away from the protruding surface. Furthermore, the protruding portion may be recessed from the protruding surface and may have a groove extending from one end to the other end of the protruding portion. Furthermore, the sintered layer may have protrusions around the protruding surface that extend toward the one member.

[0006] From another perspective, the joint to which the present invention applies comprises a first member, a second member, and a sintered layer formed by sintering a metal paste applied between a first surface of the first member facing the second member and a second surface of the second member facing the first member, wherein the first member is recessed from the first surface and has a groove extending from one end to the other, and the sintered layer is formed in a region including at least a part of the groove. [Effects of the Invention]

[0007] According to the present invention, the increase in pressure caused by angularity is suppressed. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an example of a schematic configuration of a joined body according to the embodiment. [Figure 2]This is a schematic diagram showing an example of a cross-section obtained by cutting the joint along section II-II in Figure 1. [Figure 3] This is a plan view of the heat sink as seen from the first side in the stacking direction. [Figure 4] This is a schematic diagram showing the movement path of a nozzle used to apply metal paste to an insulating substrate. [Figure 5] (a) is a diagram showing the state in which the nozzle is being moved while metal paste is being dispensed from the nozzle, (b) is a diagram showing the state in which the dispensing of metal paste from the nozzle has stopped, and (c) is a diagram showing the state in which the nozzle is being moved away from the insulating substrate. [Figure 6] This figure shows semiconductor modules with a coating layer formed on them stacked on a heat sink. [Figure 7] This is a diagram illustrating the joint according to Modification Example 1. [Figure 8] This is a plan view of the heat sink according to Modification 1, as seen from the second side in the stacking direction. [Figure 9] This diagram illustrates the placement of a metal mask on an insulating substrate. [Figure 10] This is a schematic cross-sectional view illustrating the process of applying metal paste using a metal mask. [Figure 11] This figure shows the schematic configuration of the joint according to modified example 2. [Figure 12] This figure shows the outer surface of the heat sink according to Modification 2. [Figure 13] This figure shows the schematic configuration of the joint according to modified example 3. [Figure 14] This is a view of the heat transfer layer according to Modification 3, seen from the stacking direction. [Modes for carrying out the invention]

[0009] <Embodiment> Embodiments of the present invention will be described in detail below with reference to the attached drawings. Figure 1 shows an example of the schematic configuration of the joint 1 according to the embodiment. The bonded body 1 according to the embodiment includes a semiconductor module 10, a heat sink 20 having a plurality of fins 22 that dissipate heat transmitted from the semiconductor module 10, and a sintered layer 30 that joins the semiconductor module 10 and the heat sink 20. In the bonded body 1, the heat sink 20 and the semiconductor module 10 are laminated. Hereinafter, the lamination direction of the heat sink 20 and the semiconductor module 10 may be simply referred to as the "lamination direction". Also, the semiconductor module 10 side in the lamination direction (the upper side in FIG. 1) may be referred to as the "first side", and the heat sink 20 side in the lamination direction (the lower side in FIG. 1) may be referred to as the "second side". Also, the bonded body 1 has a rectangular shape when viewed from the lamination direction. Hereinafter, the longitudinal direction of this rectangle may be simply referred to as the "longitudinal direction", and the short side direction of the rectangle may be simply referred to as the "short side direction". Also, the front side in the short side direction in FIG. 1 may be simply referred to as the "front side", and the back side in the short side direction may be simply referred to as the "back side". Also, when viewed from the front side in the short side direction and with the first side in the lamination direction as the top, the right side may be referred to as the "third side" in the longitudinal direction, and the left side may be referred to as the "fourth side".

[0010] Also, although not shown in the figure, the bonded body 1 is used by being attached to a case having an internal space through which a coolant flows, for example, such that the fins 22 of the heat sink 20 described later contact the coolant. Thereby, the heat generated in the semiconductor module 10 and conducted to the heat sink 20 through the sintered layer 30 is dissipated to the coolant. Alternatively, the bonded body 1 may be an air-cooled type in which the heat sink 20 is disposed in a space through which air flows.

[0011] FIG. 2 is a schematic diagram showing an example of a cross section obtained by cutting the bonded body 1 at the II-II portion in FIG. 1. The semiconductor module 10 includes an insulating substrate 11 and semiconductor elements 13 mounted on the surface of the insulating substrate 11 on the first side. The semiconductor module 10 also includes an element bonding layer 15 that bonds the surface of the insulating substrate 11 on the first side and the semiconductor elements 13, and a sealing resin portion 17 that protects the semiconductor elements 13. <​The insulating substrate 11 includes an insulating layer 111 that insulates the semiconductor element 13 and the heat sink 20, a wiring layer 112 formed on the first-side surface of the insulating layer 111 and including wirings for supplying power to the semiconductor element 13, and a heat transfer layer 113 formed on the second-side surface of the insulating layer 111 and transferring heat generated from the semiconductor element 13 to the heat sink 20.

[0013] The encapsulating resin portion 17 exposes the second-side surface of the insulating substrate 11 from the encapsulating resin portion 17 and covers the periphery of the insulating substrate 11, the semiconductor element 13, and the element bonding layer 15. As the material of the encapsulating resin portion 17, for example, a molding resin is used.

[0014] The sintered layer 30 joins the heat transfer layer 113 of the insulating substrate 11 and the heat sink 20. Examples of the sintered layer 30 include copper sintering or silver sintering. The sintered body constituting the sintered layer 30 can be obtained, for example, by applying a metal paste in which metal particles are dispersed between the insulating substrate 11 and the heat sink 20 and sintering it. Examples of the method of sintering the metal paste to obtain the sintered body include non-pressure sintering, pressure sintering, and electric current sintering. The sintered layer 30 has a protrusion 31 protruding toward the base portion 21 (described later) at the end of the third side in the longitudinal direction. This protrusion 31 is generated, for example, when the metal paste is discharged using a nozzle and the discharge of the metal paste is stopped, it is difficult for the highly viscous metal paste to drain, and the metal paste is pulled and rises as the nozzle moves. Further, the protrusion 31 is generated, for example, when the metal paste is applied by screen printing using a metal mask and the metal paste adhering to the edge of the metal mask rises when the metal mask is removed.

[0015] As the metal particles used in the sintered body constituting the sintered layer 30, for example, particles of metal selected from copper (Cu), silver (Ag), or an alloy of copper and silver (Cu-Ag) can be used. Alternatively, as the metal particles, for example, particles made of copper coated with silver on the surface may be used. Among these metal particles, copper particles are preferred. By using copper particles as the metal particles forming the sintered body, the heat transfer between the semiconductor module 10 and the heat sink 20 via the sintered layer 30 can be improved. Furthermore, the sintered body constituting the sintered layer 30 may contain non-metallic components such as intermetallic compounds, inorganic compounds, and resins.

[0016] Here, we will explain the heatsink 20 using Figure 3 in addition to Figure 2. Figure 3 is a plan view of the heat sink 20 as seen from the first side in the stacking direction. The heat sink 20 comprises a flat base portion 21, a plurality of fins 22 protruding from the base portion 21, and a protruding portion 23 protruding from the base portion 21. The base portion 21 has a rectangular shape when viewed from the stacking direction. The base portion 21 has a fin side surface 211, which is the side from which the multiple fins 22 protrude, and an outer surface 212, which is the surface facing the semiconductor module 10.

[0017] Each fin 22 of the heatsink 20 protrudes from the fin side surface 211 of the base portion 21 in a direction perpendicular to the plate surface of the base portion 21. Each fin 22 is flat and extends in a direction perpendicular to the plate surface of the base portion 21 and in the short-side direction of the base portion 21. Multiple fins 22 are arranged in a line along the longitudinal direction of the base portion 21.

[0018] The protruding portion 23 is a rectangular prism shape that protrudes from the outer surface 212 in a direction perpendicular to the plate surface of the outer surface 212. The protruding portion 23 has a protruding surface 231 which faces the first side in the stacking direction, and a groove portion 233 which is recessed from the protruding surface 231. The protruding surface 231 has a rectangular shape when viewed from the stacking direction. The longitudinal direction of the protruding surface 231 is aligned with the longitudinal direction of the base portion 21. The groove 233 is composed of two straight grooves 233a and 233b. Groove 233a is provided along the short direction of the protruding surface 231, from the front end to the back end in the short direction. Groove 233b is provided along the longitudinal direction of the protruding surface 231, from the third end to the fourth end in the longitudinal direction. Grooves 233a and 233b intersect at the center of the rectangle of the protruding surface 231.

[0019] The material of the heat sink 20 is not particularly limited, but examples include aluminum, aluminum alloy, copper, and copper alloy. The heat sink 20 may also have a plating layer, such as silver plating or gold plating. Forming these plating layers on the protruding surface 231 of the base portion 21 increases the bonding strength between the semiconductor module 10 and the insulating substrate 11 via the sintered layer 30.

[0020] In the heat sink 20, the metal used on the surface to which the insulating substrate 11 is joined may include copper, nickel, silver, palladium, gold, platinum, lead, cobalt, tin, aluminum, or an alloy of two or more metals selected from these. Preferably, the metal used on the surface to which the insulating substrate 11 is joined is copper, nickel, silver, palladium, gold, or an alloy of two or more metals selected from these. More preferably, the metal used on the surface to which the insulating substrate 11 is joined is copper, nickel, or silver.

[0021] (Joining process) Next, we will describe the bonding process in which the semiconductor module 10 and the heat sink 20 are joined via a sintered layer 30. Figure 4 is a schematic diagram showing the movement path of the nozzle 160 (see Figure 5) that applies metal paste to the insulating substrate 11. Figure 5(a) shows the state in which the nozzle 160 is being moved while discharging metal paste from the nozzle 160. Figure 5(b) shows the state in which the discharging of metal paste from the nozzle 160 has stopped. Figure 5(c) shows the state in which the nozzle 160 has been moved away from the heat transfer layer 113 of the insulating substrate 11. Figure 6 shows a state in which semiconductor modules 10 with a coating layer 40 formed on them are stacked on a heat sink 20.

[0022] The bonding process includes a coating process, a lamination process, and a sintering process. The coating process involves applying a metal paste to the heat transfer layer 113 of the insulating substrate 11 of the semiconductor module 10 to form a coating layer 40 of the metal paste. The lamination process involves laminating the heat transfer layer 113 of the insulating substrate 11 and the heat sink 20 via the coating layer 40 of the metal paste. The sintering process involves heating the coating layer 40 of the metal paste to form a sintered layer 30.

[0023] (Coating process) Figure 4 is a view of the heat transfer layer 113 of the insulating substrate 11 of the semiconductor module 10 from the second side. Figure 4 shows a dashed line R1 to indicate the region in which the protruding surface 231 of the heat sink 20 makes contact when the semiconductor module 10 is attached to the heat sink 20. In the longitudinal direction, the heat transfer layer 113 and the protruding surface 231 make contact in the region fourth to this dashed line R1. Furthermore, Figure 4 shows the path the dispenser nozzle 160 moves along when applying the metal paste, indicated by arrows. Here, the solid lines indicate movement while dispensing the metal paste, and the dashed lines indicate movement without dispensing the metal paste. As shown in Figure 4, the dispenser starts dispensing metal paste from the nozzle 160 at the fourth end of the heat transfer layer 113 in the longitudinal direction, and continues dispensing the metal paste, moving the nozzle 160 along the longitudinal direction. The dispenser stops dispensing the metal paste when the nozzle 160 crosses the dashed line R1 and is third to the dashed line R1. The dispenser then moves the nozzle 160 to the next dispensing position, which is the fourth side of the heat transfer layer 113 in the longitudinal direction. Once the dispenser moves the nozzle 160 to the fourth side of the heat transfer layer 113 in the longitudinal direction, it moves in the short direction from the already applied position and starts dispensing the metal paste. The dispenser repeats dispensing the metal paste from the nozzle 160 along the longitudinal direction to a position third to the dashed line R1. The dispenser repeatedly dispenses metal paste in the longitudinal direction, applying the metal paste to the region fourth to the dashed line R1 and the region third to the longitudinal direction to form a coating layer 40. Note that while Figure 4 illustrates an example of a pathway when applying with a single dispenser, multiple dispensers may be used.

[0024] In Figure 5(a), the nozzle 160 moves from the fourth side to the third side in the longitudinal direction while continuously dispensing metal paste from the nozzle 160. Then, as shown in Figure 5(b), when the distance exceeds the dashed line R1 in the longitudinal direction, the movement of the nozzle 160 is stopped, and the discharge of the metal paste is halted. Then, as shown in Figure 5(c), when the nozzle 160 is moved away from the heat transfer layer 113 to move to the next discharge position, the metal paste attached to the tip of the nozzle 160 strings and rises up. At this time, a projection 41 extending away from the heat transfer layer 113 is formed. That is, in the example of the movement path of the nozzle 160 shown in Figure 4, the metal paste rises up and a projection 41 is likely to be formed at the position where the solid line arrow in Figure 4 changes to a dashed line. When this projection 41 of the metal paste hardens in the sintering process, it becomes a projection 31 of the sintered layer 30. In this embodiment, the discharge of the metal paste is stopped in a region different from the region in contact with the protruding surface 231, and the nozzle 160 is moved. In other words, the coating layer 40 is formed in the region in contact with the protruding surface 231 and in the region surrounding the protruding surface 231.

[0025] (Lamination process) In the lamination process, the heat sink 20 and the insulating substrate 11 are laminated via the metal paste of the coating layer 40 formed in the coating process. As shown in Figure 6, in this embodiment, the protrusions 41 of the coating layer 40 extend toward the outer surface 212 of the heat sink 20 without contacting the protruding surface 231 of the heat sink 20. When laminating the heat sink 20 and the insulating substrate 11 via the coating layer 40, the coating layer 40 between the heat sink 20 and the insulating substrate 11 may or may not be pressurized. The method of applying force to the heat sink 20 and the insulating substrate 11 is not particularly limited, but examples include placing a weight on the semiconductor module 10.

[0026] (Sintering process) The sintering process involves heating the coating layer 40 to sinter the metal paste constituting the coating layer 40, forming a sintered layer 30 (see Figure 2) which is made up of a sintered body that joins the heat sink 20 and the insulating substrate 11, thereby manufacturing the joined body 1 (see Figure 2).

[0027] The temperature at which the coating layer 40 is heated during the sintering process varies depending on the type of metal particles contained in the metal paste, but a range of 150°C to 500°C can be used as an example. Furthermore, in the first sintering step, the insulating substrate 11 and the heat sink 20 may be sintered while applying pressure in the stacking direction via the coating layer 40, or the insulating substrate 11 and the heat sink 20 may be sintered without applying pressure.

[0028] In the sintering process, when the metal paste constituting the coating layer 40 is sintered, gases such as outgassing from the solvent contained in the metal paste are generated. If the generated gas remains on the coating layer 40 while the metal paste is sintered, voids may be generated in the sintered layer 30 formed from the coating layer 40. If voids are generated, the bonding strength between the insulating substrate 11 and the heat sink 20 via the sintered layer 30 may decrease. In addition, if voids are generated, the heat dissipation efficiency of the heat generated by the semiconductor elements 13 of the semiconductor module 10 may decrease. In contrast, in this embodiment, since gas can be transported to the outside via the groove 233, it is possible to suppress the generation of voids caused by gas generated from the solvent contained in the metal paste.

[0029] The bonded body 1, formed as described above, comprises a heat sink 20, a semiconductor module 10, and a sintered layer 30 formed by sintering a metal paste applied between the heat sink 20 and the semiconductor module 10. The heat sink 20 of the bonded body 1 has a protruding portion 23 that protrudes toward the semiconductor module 10, and the protruding portion 23 has a protruding surface 231 that protrudes most toward the semiconductor module 10. Furthermore, the sintered layer 30 of the bonded body 1 is formed on the protruding surface 231 and the region surrounding the protruding surface 231. This suppresses the placement of the edges of the coating layer 40 in the region of the protruding surface 231, and makes it easier for the surface of the coating layer 40 in contact with the protruding surface 231 to be in a uniform state. The bonded body 1 can reduce the pressure required to flatten the coating layer 40 compared to the case where the edges of the coating layer 40 are in contact with the protruding surface 231.

[0030] Furthermore, the protruding portion 23 is recessed from the protruding surface 231 and is provided with grooves 233a and 233b extending from one end to the other end of the protruding portion 23. This allows gas within the coating layer 40 to be discharged to the outside through grooves 233a and 233b, thereby suppressing the generation of voids caused by gases generated from the solvent contained in the metal paste.

[0031] Furthermore, as in Patent Document 1, for example, there are methods to discharge gas to the outside by intermittently applying metal paste and discharging the gas from cavities where metal paste has not been formed. As mentioned above, when metal paste is applied intermittently, the edges of the metal paste tend to rise, and it becomes necessary to apply pressure to suppress the rising portion. In the joint 1, since grooves 233 are provided in the heat sink 20, the metal paste is applied uniformly without intermittently. As a result, the positioning of the edges of the coating layer 40 in the region of the protruding surface 231 is suppressed, and the surface of the coating layer 40 in contact with the protruding surface 231 tends to be uniform. In the joint 1, the force pressing the protruding surface 231 against the coating layer 40 can be suppressed compared to the case where the edges of the coating layer 40 are in contact with the protruding surface 231.

[0032] Furthermore, the sintered layer 30 has protrusions 31 that project toward the heat sink 20 around the protruding surface 231. This suppresses contact between the protrusions 41 and the protruding surface 231 during the lamination process, thereby suppressing variations in the pressure applied to the coating layer 40 sandwiched between the protruding surface 231 and the heat transfer layer 113, and thus suppressing bonding defects.

[0033] <Example 1> Figure 7 is a diagram illustrating the joint 2 according to the modified example 1. Figure 8 is a plan view of the heat sink 120 according to Modification 1, as seen from the first side in the stacking direction. Next, a modified example 1 of the embodiment will be described. The joint 2 according to the modified example 1 differs from the joint 1 according to the embodiment in the shape of the protruding portion 24 of the heat sink 120. Also, the joint 2 differs from the joint 1 according to the embodiment in that the coating layer 140 is applied using a metal mask. Furthermore, the shape of the sintered layer 130 of the joint 2 differs from the shape of the sintered layer 30 of the joint 1 according to the embodiment. Note that the same reference numerals are used for functions similar to those in the embodiment, and their detailed explanation is omitted here. The assembled body 2 comprises a semiconductor module 10, a heat sink 120, and a sintered layer 130. The heatsink 120 comprises a base portion 21, fins 22, and protruding portions 24. The protruding portion 24 is a truncated pyramidal shape extending from the outer surface 212 of the base portion 21 toward the first side in the stacking direction, and comprises a protruding surface 241 which faces toward the first side in the stacking direction, and a side surface 242 which is the side of the truncated pyramidal shape and is inclined with respect to the stacking direction. The protruding portion 24 also comprises a groove portion 243 provided on the protruding surface 241. The groove portion 243 is composed of two linear grooves 243a and groove 243b.

[0034] The sintered layer 130 differs in the shape of the protrusions 131 from those of the embodiment. In the embodiment, the protrusions 31 rose from the edge of the short side located on the third side in the longitudinal direction, but in this modified example 1, the sintered layer 130 has protrusions 131 that extend toward the base portion 21 from four edges. These protrusions 131 were created by using a metal mask when applying the metal paste by screen printing, and will be described later.

[0035] [Joining process] Next, the process of joining the semiconductor module 10 and the heat sink 120 via the sintered layer 130 will be described. The bonding process begins with a coating step in which a metal paste is applied to the heat transfer layer 113 of the insulating substrate 11 of the semiconductor module 10 to form a coating layer 140 of the metal paste (see Figure 10). Next, a lamination step is performed in which the heat transfer layer 113 of the insulating substrate 11 and the heat sink 120 are laminated together via the coating layer 140 of the metal paste. Furthermore, a sintering step is performed in which the coating layer 140 of the metal paste is sintered to form a sintered layer 130.

[0036] (Coating process) In the coating process of Modification 1, a metal mask 171 is used to apply the metal paste. Figure 9 is a diagram illustrating the arrangement of the metal mask 171 on the insulating substrate 11. Figure 10 is a schematic cross-sectional view illustrating the process of applying metal paste using a metal mask 171. Figure 9 shows the semiconductor module 10 as viewed from the second side in the stacking direction. The metal mask 171 is plate-shaped, and its shape, when viewed perpendicular to the plate surface, is a rectangular annular shape. The inner circumference of the metal mask 171 is shaped to coincide with the outer circumference of the thermal conductive layer 113 of the insulating substrate 11. The metal mask 171 is placed on the sealing resin portion 17 with its inner circumference aligned with the outer circumference of the thermal conductive layer 113. Also in Figure 9, the region R2 that faces the protruding surface 241 (see Figure 8) of the heat sink 120 (see Figure 7) when stacking the insulating substrate 11 and the heat sink 120 is shown by a dashed line. Figure 10(a) shows the state in which the metal paste is placed on the metal mask 171 and the metal paste is started to be spread using the squeegee 172. Figure 10(b) shows the state in which the metal paste is filled into the frame of the metal mask 171 and the coating layer 140 is formed. Figure 10(c) shows the state in which the metal mask 171 is moving away from the insulating substrate 11. As the metal mask 171 moves, the metal paste of the coating layer 140 that was in contact with the metal mask 171 is pulled by the metal mask 171, causing stringing and forming protrusions 141 that extend away from the insulating substrate 11. As shown in Figure 9, the inner circumference of the metal mask 171 is rectangular, and the protrusions 141 are formed at the four edges of the rectangular coating layer 140.

[0037] (Lamination process) In the lamination process, the heat sink 120 and the insulating substrate 11 are laminated via the metal paste of the coating layer 140 formed in the coating process. Similar to the embodiment, in this modified example 1, the protrusions 141 of the coating layer 140 do not come into contact with the protruding surface 241 (see Figure 8) and side surface 242 (see Figure 8) of the heat sink 120, but extend toward the outer surface 212 of the heat sink 120.

[0038] (Sintering process) The sintering process involves heating the coating layer 140 to sinter the metal paste that constitutes the coating layer 140, thereby forming a sintered layer 130 consisting of a sintered body that joins the heat sink 120 and the insulating substrate 11.

[0039] The bonded body 2 formed as described above comprises a heat sink 120, a semiconductor module 10, and a sintered layer 130 formed by sintering a metal paste applied between the heat sink 120 and the semiconductor module 10. The heat sink 120 of the bonded body 2 has a protruding portion 24 that protrudes toward the semiconductor module 10, and the protruding portion 24 has a protruding surface 241 that protrudes most toward the semiconductor module 10. The sintered layer 130 of the bonded body 2 is formed over the entire area of ​​the protruding surface 241 and the area surrounding the protruding surface 241. This suppresses the placement of the edges of the coating layer 140 in the area of ​​the protruding surface 241, and makes it easier for the surface of the coating layer 140 in contact with the protruding surface 241 to be in a uniform state. The bonded body 2 can reduce the pressure required to flatten the coating layer 140 compared to the case where the edges of the coating layer 140 are in contact with the protruding surface 241.

[0040] The protruding portion 24 has a side surface 242 around the protruding surface 241 that is inclined away from the semiconductor module 10 as it moves away from the protruding surface 241 in a direction perpendicular to the stacking direction. This increases the volume to which heat can be transferred compared to when the side surface 242 is aligned with the stacking direction, thereby improving the heat dissipation performance of the heat sink 120.

[0041] Furthermore, the protruding portion 24 is recessed from the protruding surface 241 and includes a groove 243b extending from the third end to the fourth end in the longitudinal direction of the protruding surface 241, and a groove 243a extending from the front end to the back end in the short direction. This allows gas within the coating layer 140 to be discharged to the outside through grooves 243a and 243b, thereby suppressing the generation of voids caused by gases generated from the solvent contained in the metal paste.

[0042] Furthermore, the sintered layer 130 has protrusions 131 that project toward the heat sink 120 around the protruding surface 241. This suppresses contact between the protrusions 131 and the protruding surface 241, thereby suppressing variations in the pressure applied to the coating layer 140 sandwiched between the protruding surface 241 and the heat transfer layer 113 during the lamination process, and thus suppressing bonding defects.

[0043] <Modification 2> In the second modification, the shape of the heatsink 20 according to the embodiment is different. Figure 11 shows a schematic configuration of the joint 3 according to the modified example 2. Figure 12 shows the outer surface 212 of the heat sink 220 according to the modified example 2. The same reference numerals are used for functions similar to those in the embodiments, and their detailed explanation is omitted here. The bonded body 3 according to the modified example 2 comprises a semiconductor module 10, a heat sink 220, and a sintered layer 30.

[0044] The heat sink 220 comprises a base portion 21 and a plurality of fins 22. A groove 213 is provided on the outer surface 212 of the base portion 21, recessed from the outer surface 212. The groove 213 comprises a groove 213a extending along the short direction from the front end to the other end along the short direction of the base portion 21, and a groove 213b extending along the longitudinal direction from the third end to the fourth end along the longitudinal direction of the base portion 21. The grooves 213a and 213b intersect in the center of the base portion 21. Thus, by providing grooves 213 on the outer surface 212 of the heat sink 220, gases such as outgassing generated during sintering can be transported to the outside through the grooves 213. Therefore, it is possible to suppress the generation of voids caused by gases generated from the solvent contained in the metal paste.

[0045] The bonded body 3 formed as described above comprises a heat sink 220 and a semiconductor module 10. Furthermore, the bonded body 3 includes a sintered layer 30 formed by sintering a metal paste applied between the outer surface 212 of the heat sink 220 facing the semiconductor module 10 and the second side surface in the stacking direction of the heat transfer layer 113 of the semiconductor module 10 facing the heat sink 220. In addition, the heat sink 220 of the bonded body 3 has grooves 213a and 213b that are recessed from the outer surface 212 and extend from one end to the other end of the heat sink 220, and the sintered layer 30 is formed in a region that includes at least a portion of the grooves 213a and 213b. In the heat sink 220 formed in this manner, the pressure required to flatten the metal paste can be reduced compared to, for example, the case where the metal paste is applied intermittently to release gas.

[0046] <Variation 3> Modification 3 differs from Modification 2 in that the groove 114 is provided in the heat transfer layer 113 instead of the heat sink 220. Figure 13 shows a schematic configuration of the joint 4 according to the modified example 3. Figure 14 is a view of the heat transfer layer 113 according to Modification 3, as seen from the stacking direction. The assembled body 4 according to the modified example 3 comprises a semiconductor module 10, a heat sink 320, and a sintered layer 30. The heat transfer layer 113 of the semiconductor module 10 is provided with grooves 114 recessed from the surface of the heat transfer layer 113. The grooves 114 include a groove 114a that extends along the short direction from the front end to the back end in the short direction of the heat transfer layer 113, and a groove 114b that extends along the longitudinal direction from the third end to the fourth end in the longitudinal direction of the heat transfer layer 113. Grooves 114a and 114b intersect in the center of the heat transfer layer 113. In Figure 14, the region R3 in which the metal paste applied to the heat sink 320 contacts the heat transfer layer 113 is shown by a dashed line.

[0047] The bonded body 4 formed as described above comprises a semiconductor module 10 and a heat sink 320. The bonded body 4 also includes a sintered layer 30 formed by sintering a metal paste applied between the second side surface of the heat transfer layer 113 facing the heat sink 320 on the semiconductor module 10 and the outer surface 212 of the heat sink 320 facing the semiconductor module 10. The thermal conductive layer 113 of the semiconductor module 10 of the bonded body 4 is recessed from the second side surface of the heat transfer layer 113 and has grooves 114a and 114b extending from one end to the other on the thermal conductive layer 113. Furthermore, the sintered layer 30 of the bonded body 4 is formed in a region that includes parts of grooves 114a and 114b. In the heat sink 320 formed in this way, it is possible to suppress the generation of voids caused by gases generated from the solvent contained in the metal paste without intermittently applying the metal paste. Furthermore, in the heat transfer layer 113 formed in this manner, the pressure required to flatten the metal paste can be reduced compared to, for example, the case where the metal paste is applied intermittently to release gas.

[0048] <Other> In the embodiment and modification 1 of the embodiment, protrusions 23 were provided on the heat sinks 20 and 120. However, the protrusions 23 may also be provided on the heat transfer layer 113 (insulating substrate 11). In this case, the metal paste coating layers 40 and 140 can be applied to the outer surface 212 of the base portion 21 of the heat sink 20 to bond the semiconductor module 10 and the heat sink 20. [Explanation of symbols]

[0049] 1,2,3,4…Assembled body, 10…Semiconductor module, 20,120,220,320…Heat sink, 30,130…Sintered layer, 31,131,41,141…Protrusion, 40,140…Coating layer, 114,213,233,243…Groove, 160…Nozzle, 171…Metal mask, 172…Squeegee, 241…Protruding surface, 242…Side

Claims

1. First member and The second member and A sintered layer formed by sintering a metal paste applied between the first member and the second member, A joint comprising, Either the first member or the second member has a protruding portion that extends toward the other member. The aforementioned protruding portion has a protruding surface that protrudes most towards the other member. The sintered layer is formed on the protruding surface and the region surrounding the protruding surface. zygote.

2. The aforementioned protrusion has an inclined portion around the protruding surface that is inclined in a direction away from the protruding surface. The joint according to claim 1.

3. The aforementioned protrusion is recessed from the protruding surface and has a groove extending from one end to the other end of the protrusion. The joint according to claim 1.

4. The sintered layer has protrusions around the protruding surface that project toward one of the members. The joint according to any one of claims 1 to 3.

5. First member and The second member and A sintered layer formed by sintering a metal paste applied between the first surface of the first member facing the second member and the second surface of the second member facing the first member, A joint comprising, The first member is recessed from the first surface and has a groove extending from one end to the other end of the first member. The sintered layer is formed in a region including at least a portion of the groove. zygote.

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