Application jig

Abstract

To provide a coating jig that can coat a silicon compound evenly and thinly.SOLUTION: A coating jig according to an embodiment coats a surface of a flat-type pressure-welding element of an electric power converting unit with particle-containing materials. The surface to be coated is a flat surface having a circular contour. The jig has a coating surface that is put along the surface to be coated, which is an elastic body having a predetermined thickness from the coating surface and has a groove diving the coating surface into a plurality of coating sections.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a coating jig. [Background technology]

[0002] For example, there is a power conversion unit that uses flat pressure-welded elements as a power conversion device. This power conversion unit is known as a semiconductor stack device. The power conversion unit has a configuration that includes multiple flat semiconductor elements and heat sinks arranged alternately, a pressure means that applies pressure to the flat semiconductor elements and heat sinks in the stacking direction, and a frame that uses studs or the like to secure them in place. Such an example is described in Patent Document 1.

[0003] In power conversion units, a silicone oil compound (hereafter referred to as "silicon compound") is applied to the contact points of elements during assembly to prevent an increase in electrical resistance. The silicone compound must be applied evenly and thinly. There was a demand to automate the application of the silicone compound. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-237096 Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the present invention is to provide an application tool capable of applying a silicone compound uniformly and thinly. [Means for solving the problem]

[0006] The application jig of the embodiment applies a particle-containing material to a surface to be applied of a flat pressure-contact element of a power conversion unit. The surface to be applied is a flat surface having a circular contour. The application jig has a coating surface that conforms to the surface to be applied. The application jig is an elastic body having a predetermined thickness from the coating surface. The application jig has grooves that divide the coating surface into multiple coating sections. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 4 is a front view showing a power conversion unit used for assembling the application jig of the embodiment. [Figure 2] FIG. 2 is a perspective view showing a pressure contact element that performs application by the application jig of the embodiment. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] 5A to 5C are process diagrams illustrating a coating method using the coating jig of the embodiment. [Figure 7] 5A to 5C are process diagrams illustrating a coating method using the coating jig of the embodiment. [Figure 8] FIG. 4 is a side cross-sectional view showing the application jig of the embodiment during application. DETAILED DESCRIPTION OF THE INVENTION

[0008] A first embodiment of the applicator according to the present invention will be described below with reference to the drawings. 1 is a front view showing a power conversion unit used for assembling an application jig according to an embodiment, in which reference numeral 10 denotes the power conversion unit.

[0009] As shown in FIG. 1, the power conversion unit 10 according to this embodiment includes a flat semiconductor element (flat pressure-welded element) 11, an electrode terminal plate (connection terminal plate) 12, a heat sink 13, an insulating spacer 14, a spherical seat 15, a pressure mechanism, a pressure support plate 16a, a pressure support plate 16b, a stud bolt 17, a fixing nut 18a, and a fixing nut 18b.

[0010] The power conversion unit 10 has a plurality of flat semiconductor elements 11 stacked on top of each other. The power conversion unit 10 is a stack device for the flat semiconductor elements 11. In the example shown in FIG. 1, the power conversion unit 10 has four flat semiconductor elements 11 stacked on top of each other. The number of stacked flat semiconductor elements 11 in the power conversion unit 10 can be set as appropriate. The plurality of flat semiconductor elements 11 are stacked with their respective main surfaces parallel to one another and are connected in series.

[0011] The flat semiconductor element 11 is disk-shaped or short cylindrical. The flat semiconductor element 11 has an outer casing with a circular outline. One axial end face of the flat semiconductor element 11 is an electrode 11a (see FIG. 2). The other axial end face of the flat semiconductor element 11 is an electrode 11a (see FIG. 2). Both electrodes 11a protrude in the axial direction of the flat semiconductor element 11.

[0012] The flat semiconductor element 11 is stacked with the heat sink 13 in a direction (stacking direction) along an axis F0 perpendicular to the main surface of the flat semiconductor element 11. The flat semiconductor element 11 and the heat sink 13 are arranged so that they are alternately stacked. The flat semiconductor element 11 and the heat sink 13 are arranged so that their central positions coincide with the axis F0. The flat semiconductor element 11 and the heat sink 13 are aligned so that their respective axial centers coincide with the axis F0.

[0013] The heat sink 13 has a rectangular outline. The heat sink 13 is approximately square. The heat sink 13 is in the form of a thick plate. The heat sink 13 is made of a conductive material with excellent heat transfer properties. The heat sink 13 is made of, for example, copper, aluminum, or an alloy containing these. The heat sink 13 has a refrigerant flow path (not shown) inside. The refrigerant flow path is connected to piping (not shown).

[0014] In the heat sink 13, a refrigerant such as water, oil, air, or gas flows through a refrigerant flow path via a pipe. The heat sink 13 promotes heat dissipation by the refrigerant flowing through the refrigerant flow path. The heat sink 13 has an inlet and an outlet for the refrigerant flow path. The inlet and outlet are connected to the pipe. The inlet introduces the refrigerant into the refrigerant flow path. The outlet discharges the refrigerant from the refrigerant flow path. The inlet and outlet are located at positions that intersect with the axis F0. The inlet and outlet are located on side surfaces that are perpendicular to the axis F0.

[0015] The heat sink 13 is in thermal contact with the flat semiconductor element 11. The heat sink 13 dissipates heat transferred from the flat semiconductor element 11. Alternatively, the heat sink 13 is in contact with the flat semiconductor element 11. The heat sink 13 cools the flat semiconductor element 11. The center position of the contact surface of the flat semiconductor element 11 with the heat sink 13 coincides with the axis F0. The center position of the end surface of the heat sink 13 with the flat semiconductor element 11 coincides with the axis F0. The center position of the contact surface of the flat semiconductor element 11 coincides with the center position of the end surface of the heat sink 13.

[0016] The number of layers of the heat sink 13 along the axis F0 may be the same as the number of layers of the flat semiconductor element 11. Note that the number of layers of the heat sink 13 may be different from that of the flat semiconductor element 11. The number of layers of the heat sink 13 may be greater than that of the flat semiconductor element 11. The number of layers of the heat sink 13 may be smaller than that of the flat semiconductor element 11.

[0017] The electrode terminal plate (connection terminal plate) 12 connects to an external circuit (not shown). The electrode terminal plate 12 is made of a conductive material. The electrode terminal plate 12 is a thin plate. The electrode terminal plate 12 contacts the electrode 11a. The electrode terminal plate 12 may be bent at a position where it does not contact the flat semiconductor element 11. The electrode terminal plate 12 is arranged between the flat semiconductor element 11 and the heat sink 13. Note that the electrode terminal plate 12 does not have to be arranged between the flat semiconductor element 11 and the heat sink 13.

[0018] The spherical seats 15 are arranged at positions that are opposite ends of the stacked flat semiconductor elements 11 and heat sinks 13 in the direction along the axis F0. The spherical seats 15 are aligned with the flat semiconductor elements 11 and heat sinks 13. The insulating spacer 14 is disposed between the stack of the flat semiconductor element 11 and the heat sink 13 and the spherical seat 15 in the direction along the axis F0. The spherical seat 15 is disposed so that the spherical portion thereof abuts against the insulating spacer 14. The center of the spherical portion of the spherical seat 15 coincides with the axis F0.

[0019] Spherical seat 15 contacts pressure support plate 16a and pressure support plate 16b on the outside of the stack in the direction along axis F0. A pressure mechanism is disposed between pressure support plate 16a and spherical seat 15. A pressure mechanism is disposed between pressure support plate 16b and spherical seat 15. The pressure mechanism is made up of a plurality of disc springs. The pressure mechanism is configured to be able to bias the plurality of disc springs in the stacking direction. The center position of the pressure mechanism coincides with the axis F0.

[0020] Two bolt holes are drilled in the pressure support plate 16a. Two bolt holes are drilled in the pressure support plate 16b. The pressure support plate 16a and the pressure support plate 16b are arranged in parallel. The bolt holes of the pressure support plate 16a and the pressure support plate 16b face each other. Stud bolts 17 are erected in both of the facing bolt holes of the pressure support plate 16a and the pressure support plate 16b.

[0021] The stud bolt 17 is erected along the axis F0. A plurality of stud bolts 17 are erected. The stud bolts 17 are erected on the same circumference centered on the axis F0. The stud bolts 17 are erected equidistantly on the circumference centered on the axis F0. A fixing nut 18a and a fixing nut 18b are screwed onto both ends of the stud bolt 17, respectively. The pressure support plate 16a and the pressure support plate 16b sandwich the stack of flat semiconductor elements 11 and heat sinks 13 with the stud bolt 17, fixing nut 18a, and fixing nut 18B. The pressure support plate 16a and the pressure support plate 16b sandwich the plurality of flat semiconductor elements 11 and heat sinks 13 that are alternately stacked in the direction along the axis F0.

[0022] Fixing nuts 18a and 18B adjust the amount of tightening to stud bolt 17. In the pressure mechanism, fixing nuts 18a and 18B adjust the amount of deflection of the disc spring depending on the amount of tightening to stud bolt 17. This allows the pressure in the overlapping direction applied between pressure support plate 16a and pressure support plate 16b to be properly adjusted. By adjusting the pressure between pressure support plate 16a and pressure support plate 16b, the pressure in the overlapping direction applied to the sandwiched multiple flat semiconductor elements 11 and heat sink 13 can be properly adjusted. When the flat semiconductor element 11 is large, the pressure applied to the flat semiconductor element 11 and the heat sink 13 in the stacking direction can become as high as several tens of kN, for example.

[0023] The power conversion unit 10 is made up of a plurality of flat semiconductor elements 11, electrode terminal plates 12, heat sinks 13, insulating spacers 14, spherical seats 15, a pressure mechanism, pressure support plates 16a, and pressure support plates 16b, all of which are stacked with their centers aligned with the axis F0. The flat semiconductor element 11 and the electrode terminal plate 12 are in contact with each other. The flat semiconductor element 11 and the electrode terminal plate 12 are in close contact with each other. The electrode terminal plate 12 is in contact with the entire surface of the electrodes 11a of the flat semiconductor element 11.

[0024] FIG. 2 is a perspective view showing a power conversion unit used for assembling the applicator jig in the embodiment. When assembling the power conversion unit 10, a particle-containing material is applied between the flat semiconductor element 11 and the electrode terminal plate 12.

[0025] The flat semiconductor element 11 has a particle-containing material applied to the surface of the electrode 11a that contacts the electrode terminal plate 12. The particle-containing material is applied to prevent an increase in electrical resistance at the contact point between the flat semiconductor element 11 and the electrode terminal plate 12. The particle-containing material improves adhesion between the flat semiconductor element 11 and the electrode terminal plate 12. The particle-containing material is a silicone oil compound. The particle-containing material is a thermal compound. The particle-containing material is formed by mixing particles of metal oxides or other materials with good thermal conductivity into silicone oil. The particle-containing material typically has the physical property of being free-flowing. The particle-containing material is sometimes called a silicone compound.

[0026] The silicon compound contains particles of a predetermined particle size. The silicon compound contains metal particles. The silicon compound contains particles of metal oxides or the like. The average particle size of the particles of metal oxides or the like is about several tens of μm. The average particle size of the particles of metal oxides or the like is about 10 μm to 90 μm. The average particle size of the particles of metal oxides or the like is about 10 μm to 50 μm. The average particle size of the particles of metal oxides or the like is about 10 μm to 30 μm. The average particle size of the particles of metal oxides or the like is about 15 μm to 25 μm.

[0027] The surface of the electrode 11a is a surface 11c to be coated. The surface 11c to be coated is a flat surface. The surface 11c to be coated has a circular outline. The surface 11c to be coated is flat. The silicone compound is applied to the entire surface 11c to be coated. The silicone compound is applied to a uniform thickness over the entire surface 11c to be coated. The silicone compound is applied to an extremely thin thickness over the entire surface 11c to be coated.

[0028] The applied silicone compound reduces the thermal resistance of the coated surface 11c by eliminating the insulating air layer between the coated surface 11c and the electrode terminal plate 12. The applied silicone compound increases the degree of thermal coupling between the coated surface 11c and the electrode terminal plate 12. The surface 11c to be coated is coated with a silicone compound by a coating jig 20 (see FIG. 3).

[0029] Fig. 3 is a perspective view showing an applicator in the embodiment, Fig. 4 is a plan view showing an applicator in the embodiment, and Fig. 5 is a side view showing a groove of the applicator in the embodiment. As shown in Figures 3 to 5, the applicator 20 has a coating surface 20a. The applicator 20 is an elastic body having a predetermined thickness from the coating surface 20a. The applicator 20 has the same contour shape as the coating surface 20a. The applicator 20 has a uniform thickness along the coating surface 20a. The applicator 20 is made of a material that does not absorb silicone compounds. The applicator 20 is made of, for example, a rubber sheet. The applicator 20 is made of, for example, silicone rubber.

[0030] The coating surface 20a is a flat surface. The coating surface 20a is an XY plane along the X-axis and Y-axis. The coating surface 20a has a normal along the Z-axis. The coating surface 20a has a circular contour. The coating surface 20a has a contour shape that is approximately the same as that of the surface 11c to be coated. The coating surface 20a has a contour shape that is slightly larger than that of the surface 11c to be coated. The surface roughness of the coating surface 20a is small. The surface roughness of the coating surface 20a is approximately the same as the average particle size of the particles contained in the silicone compound. The surface roughness of the coating surface 20a is slightly smaller than the average particle size of the particles contained in the silicone compound.

[0031] The application surface 20a has long section grooves (grooves) 21 and short section grooves (grooves) 22. The long section grooves 21 and the short section grooves 22 intersect with each other. The long section grooves 21 and the short section grooves 22 are perpendicular to each other. The long section grooves 21 and the short section grooves 22 are formed on the application surface 20a. The long section grooves 21 and the short section grooves 22 have the same depth in the Z direction. The long section grooves 21 and the short section grooves 22 have the same width dimension on the application surface 20a. The long section grooves 21 and the short section grooves 22 divide the application surface 20a into a plurality of application sections 25.

[0032] The long section grooves 21 extend in the X direction. The long section grooves 21 are formed linearly along the application surface 20a. The long section grooves 21 have the same width dimension in the Y direction throughout their entire length in the X direction. The long section grooves 21 have the same depth dimension in the Z direction throughout their entire length in the X direction. A plurality of long section grooves 21 are formed. The plurality of long section grooves 21 are parallel to each other. Adjacent long section grooves 21 have the same width dimension in the Y direction. The long section grooves 21 are equally spaced apart in the Y direction. Both ends of the long section groove 21 in the X direction reach the contour of the application surface 20a. Adjacent long section grooves 21 can have different lengths in the X direction. Between adjacent long section grooves 21, the application sections 25 form a row.

[0033] The short section grooves 22 extend in the Y direction. The short section grooves 22 are formed linearly along the application surface 20a. The short section grooves 22 have the same X-direction width dimension over their entire length in the Y direction. The short section grooves 22 have the same Z-direction depth dimension over their entire length in the Y direction. A plurality of short section grooves 22 are formed. The plurality of short section grooves 22 are parallel to each other. Adjacent short section grooves 22 have the same width dimension in the X direction. The short section grooves 22 are spaced equally apart in the X direction. Both ends of the short section grooves 22 in the Y direction reach the adjacent long section groove 21. The short section grooves 22 whose both ends reach the long section groove 21 have the same length in the X direction. Between adjacent long section grooves 21, the short section grooves 22 have the same length in the Y direction.

[0034] One end of the short section groove 22 in the Y direction reaches the long section groove 21, and the other end reaches the contour of the application surface 20a. The short section groove 22 whose other end reaches the contour of the application surface 20a has a different length in the X direction. The short section groove 22 whose other end reaches the contour of the application surface 20a has a shorter length in the X direction than the short section groove 22 whose both ends reach the long section groove 21. The short section groove 22 whose other end reaches the contour of the application surface 20a can have a different length in the Y direction.

[0035] Between adjacent long section grooves 21, the short section grooves 22 have the same length in the Y direction. Between adjacent long section grooves 21, the application surface 20a is divided in the X direction to form application sections 25. Rows of coating sections 25 adjacent to each other in the Y direction across the long section groove 21 are offset in position in the X direction. Rows of coating sections 25 aligned in the Y direction across a row of coating sections 25 have the same positions in the X direction. In a row of coating sections 25, every other coating section 25 has the same positions in the X direction. The coating sections 25 are staggered in the Y direction. The coating sections 25 are arranged in a staggered pattern in the Y direction.

[0036] Each of the multiple coating sections 25 has a rectangular outline when viewed in the direction of the axis F1. Each of the multiple coating sections 25 has a rectangular outline when viewed in the direction of the axis F1. Each of the multiple coating sections 25 has a square outline when viewed in the direction of the axis F1. Each of the multiple coating sections 25 has the same outline shape when viewed in the direction of the axis F1. The multiple coating sections 25 form a row along the X direction. Multiple rows of the coating sections 25 are lined up in the Y direction. The rows of the multiple coating sections 25 are arranged parallel to each other. Adjacent coating sections 25 in the X direction have their sides extending in the X direction arranged on the same straight line. Adjacent coating sections 25 in the X direction are spaced apart at a distance equal to the width dimension of the short section groove 22.

[0037] Of the multiple application sections 25, the application sections 25 at positions that overlap the contour of the application surface 20a have an arc-shaped contour that matches the contour of the application surface 20a.

[0038] Of the multiple application sections 25, the central application section 25a, where the axis F1, which is the center of the contour of the application surface 20a, is located, has a dimension in the X direction that is longer than the other application sections 25. Specifically, the central application section 25a has a dimension in the X direction that is approximately three times larger than the other application sections 25. The central application section 25a has a shape in which three application sections 25 are connected in the X direction. The central application section 25a has a contour shape whose long side is in the same direction as the row formed by the other application sections 25.

[0039] The contour shape of the central application section 25a is symmetrically disposed with respect to the axis F1. The contour shape of the central application section 25a is disposed with the axis F1 at its center. The central application section 25a may be disposed so that the axis F1 is located at a position other than the center, as long as the axis F1 is located within the contour shape. The application sections 25 have the same contour shape except for the central application section 25a.

[0040] The coating section 25 is surrounded by the long section groove 21 and the short section groove 22. The contour of the coating section 25 is formed by the long section groove 21 and the short section groove 22. The contour of the coating section 25 is formed by the boundary between the side wall 21a of the long section groove 21 and the coating surface 20a. The contour of the coating section 25 is formed by the boundary between the side wall 22a of the short section groove 22 and the coating surface 20a.

[0041] The long section groove 21 has a flat side wall 21a. The long section groove 21 has a side wall 21a extending along the ZX plane. The long section groove 21 has a side wall 21a that intersects with the application surface 20a. The long section groove 21 has a side wall 21a that is perpendicular to the application surface 20a. The long section groove 21 has a side wall 21a that extends along the axis F1. The side wall 21a is parallel to the opposing side wall 21a inside the long section groove 21. The long section groove 21 has a side wall 21a that is perpendicular to the side wall 22a of the short section groove 22.

[0042] The side walls 22a of the short section groove 22 are flat. The side walls 22a of the short section groove 22 extend along the YZ plane. The side walls 22a of the short section groove 22 intersect with the application surface 20a. The side walls 22a of the short section groove 22 are perpendicular to the application surface 20a. The side walls 22a of the short section groove 22 extend along the axis F1. The side walls 22a are parallel to the opposing side walls 22a inside the short section groove 22. The side walls 22a of the short section groove 22 are perpendicular to the side walls 22a.

[0043] The boundary between the long section groove 21 and the application surface 20a rises vertically to the application surface 20a. The side wall 21a rises vertically to the application surface 20a. The side wall 21a has the same Z-direction height over its entire length in the X direction. The long section groove 21 has the same Z-direction depth over its entire length in the X direction. The long section grooves 21 have flat bottoms. The long section grooves 21 have bottoms that extend along the XY plane. The long section grooves 21 have bottoms that are parallel to the application surface 20a. The long section grooves 21 have bottoms that are perpendicular to the side walls 21a.

[0044] The boundary between the short section groove 22 and the application surface 20a rises vertically to the application surface 20a. The side walls 22a rise vertically to the application surface 20a. The short section groove 22 has the same Z-direction depth over its entire length in the Y direction. The side walls 22a have the same Z-direction height over its entire length in the Y direction. The short section groove 22 has a flat bottom. The short section groove 22 has a bottom that extends along the XY plane. The short section groove 22 has a bottom that is parallel to the application surface 20a. The short section groove 22 has a bottom that is perpendicular to the side wall 22a.

[0045] The application section 25 and the central application section 25a have the same height in the Z direction around the entire periphery. When the same pressure in the Z direction is applied to the entire application surface 20a, the application section 25 and the central application section 25a deform in the same manner.

[0046] Fig. 6 is a perspective view showing the steps of a coating method using the coating jig of the embodiment, Fig. 7 is a perspective view showing the steps of a coating method using the coating jig of the embodiment, and Fig. 8 is a side view showing deformation of the groove of the coating jig during coating of the embodiment. When applying the silicone compound to the surface 11c to be coated using the coating jig 20, the silicone compound is adhered to the surface 20a to be coated.

[0047] To apply the silicone compound to the application surface 20a, first, a reservoir 26 for storing the silicone compound is prepared, as shown in FIG. The storage container 26 has a diameter dimension slightly larger than that of the applicator jig 20. The storage container 26 is cylindrical with a bottom. The storage container 26 is open at the top. The top opening of the storage container 26 has a diameter dimension slightly larger than that of the top opening. The storage container 26 stores the silicone compound inside. The bottom surface 26a of the storage container 26 is flat.

[0048] To apply the silicone compound to the application surface 20a, the application jig 20 is inserted into the storage container 26. At this time, the application surface 20a is maintained facing the bottom surface 26a. The application jig 20 is then lowered toward the storage container 26. The application surface 20a is brought into contact with the bottom surface 26a.

[0049] Once the application surface 20a comes into contact with the bottom surface 26a, the silicone compound is spread over the application surface 20a. The application jig 20 is rotated around the axis F1. The application jig 20 moves back and forth around the axis F1. During this process, the application surface 20a does not absorb the silicone compound. Because the bottom surface 26a is flat, the metal particles contained in the silicone compound adhere uniformly to the application surface 20a.

[0050] Once a sufficient amount of silicone compound has been applied to the application surface 20a, the application surface 20a is separated from the bottom surface 26a. The application jig 20 is raised to position the application surface 20a outside the storage container 26. The metal particles contained in the silicone compound remain uniformly attached to the application surface 20a.

[0051] Next, as shown in Figure 7, the application jig 20 with the silicone compound attached is brought into contact with the flat semiconductor element 11. The application surface 20a with the silicone compound attached is brought into contact with the surface 11c to be applied. The surface 11c to be applied and the application surface 20a are maintained parallel to each other. The application surface 20a with the silicone compound attached is pressed against the surface 11c to be applied. The application surface 20a is pressed against the surface 11c to be applied in the Z direction. The entire application surface 20a is pressed uniformly against the surface 11c to be applied. The axis F0 and axis F1 of the surface 11c to be applied and the application surface 20a coincide with each other.

[0052] When pressed against the surface 11c to be coated, the coating jig 20 deforms as shown in FIG. 8. The coating jig 20 deforms so that the width dimension of the long section groove 21 in the X direction decreases. The long section groove 21 deforms so that the opposing side walls 21a approach each other. The opposing side walls 21a deform so that they bulge toward the inside of the long section groove 21. The contour of the coating surface 20a deforms so that they bulge away from the axis F1. The side walls 21a deform so that their height in the Z direction decreases. The side walls 21a maintain the same Z height over the entire length in the X direction.

[0053] The application jig 20 deforms so that the Y-direction width dimension of the short section groove 22 decreases. The short section groove 22 deforms so that opposing side walls 22a approach each other. The opposing side walls 22a deform so that they bulge toward the inside of the short section groove 22. The contour of the application surface 20a deforms so that they bulge in a direction away from the axis F1. The side walls 22a deform so that their Z-direction height decreases. The side walls 22a maintain the same Z-direction height over the entire length in the X direction.

[0054] At this time, the coating section 25 and the central coating section 25a are deformed so that their height in the Z direction is smaller than the bottom of the long section groove 21 and the short section groove 22. In the coating section 25 and the central coating section 25a, the coating surface 20a extends along the XY plane. The coating section 25 and the central coating section 25a press the surface 11c to be coated with the same force in the Z direction.

[0055] In this state, the application jig 20 is rotated around the axis F1. While the application jig 20 is rotating, the state in which the application surface 20a is pressed against the surface 11c to be applied is maintained. The application surface 20a with the silicone compound attached thereto is rotated relative to the surface 11c to be applied. The application surface 20a with the silicone compound attached thereto is rotated relative to the surface 11c to be applied. The application surface 20a with the silicone compound attached is rotated back and forth relative to the surface 11c to be applied.

[0056] The silicone compound is applied to the surface 11c to be coated by the rotation of the applicator 20. The silicone compound is applied to the entire surface 11c to be coated by the rotation of the applicator 20. At this time, the coating section 25 and the central coating section 25a rotate around the axis F1 in accordance with the rotation of the applicator 20. The contours of the coating section 25 and the central coating section 25a intersect with the direction of rotation around the axis F1.

[0057] A thin film of silicone compound exists between the application surface 20a and the surface 11c to be applied. The contours of the application section 25 and the central application section 25a remove excess silicone compound from the surface 11c to be applied. The long section groove 21 and the short section groove 22 remove excess silicone compound from the surface 11c to be applied. The side walls 21a and 22a remove overflowing silicone compound from the surface 11c to be applied, preventing the application of excess silicone compound to the surface 11c to be applied.

[0058] The application section 25 has a rectangular contour, which reduces friction between the application section 25 and the surface 11c to be applied. The central application section 25a has a rectangular contour, which reduces friction between the central application section 25a and the surface 11c to be applied. Because the central application section 25a is long in the X direction, it is possible to prevent leakage of application near the center of the surface 11c to be applied. Because the central application section 25a is long in the X direction, it is possible to prevent excessive application of silicone compound even near the center of the surface 11c to be applied. Because the central application section 25a is long in the X direction, it is possible to apply silicone compound uniformly even near the center of the surface 11c to be applied.

[0059] The staggered application sections 25 rotate around the axis F1, sliding over the entire surface 11c to be coated. That is, the contour of any of the application sections 25 passes over the surface 11c to be coated, or the application surface 20a in contact with the surface 11c slides over the surface 11c to be coated. This allows the silicone compound to be applied evenly over the entire surface 11c to be coated.

[0060] At the center of the application surface 20a, the central application section 25a is long in the X direction, which allows the silicone compound to be applied uniformly.At the center of the application surface 20a, the central application section 25a is long in the X direction, which prevents uneven application of the metal particles contained in the silicone compound.

[0061] This allows the metal particles contained in the silicone compound to be applied uniformly over the entire surface 11c to be coated. It also prevents uneven application of the metal particles contained in the silicone compound to the surface 11c to be coated. It also prevents only the oil of the silicone compound from being applied over the entire surface 11c to be coated.

[0062] By controlling the pressing force of the elastic applicator 20 against the surface 11c to be coated, the metal particles can be uniformly applied to the surface 11c to be coated. By controlling the pressing force of the elastic applicator 20 against the surface 11c to be coated, the thickness of the metal particles applied to the surface 11c to be coated can be controlled. By controlling the pressing force of the applicator 20 against the surface 11c to be coated, the degree of elastic deformation of the applicator 20 can be controlled. Since the applicator 20 is made of an elastic body, it is easy to maintain the pressing force between the application surface 20a and the surface 11c to be applied uniformly over the entire area.

[0063] The applicator 20 being an elastic body can prevent the metal particles from being absorbed into the applicator 20. The applicator surface 20a has a fine texture, so that the metal particles can be uniformly attached to the applicator surface 20a. The applicator surface 20a has a fine texture, so that the metal particles can be uniformly applied to the surface 11c to be coated. The applicator surface 20a has a fine texture, so that the metal particles can be prevented from being absorbed into the applicator 20.

[0064] By controlling the relative rotation speed between the coating surface 20a and the surface 11c to be coated in accordance with the viscosity of the silicone compound, it is possible to control the film thickness.

[0065] When application of the silicone compound to the surface 11c to be coated is completed, the application jig 20 is separated from the flat semiconductor element 11. When application of the silicone compound to one surface 11c to be coated of the flat semiconductor element 11 is completed, application of the silicone compound to the other surface 11c to be coated of the flat semiconductor element 11 is performed in the same manner.

[0066] After the application of the silicone compound to the flat semiconductor element 11 is completed, the power conversion unit 10 is assembled as shown in FIG. At this time, the axes of the flat semiconductor elements 11, the electrode terminal plate 12, the heat sink 13, the insulating spacer 14, the spherical seat 15, the pressure mechanism, the pressure support plate 16a, and the pressure support plate 16b are aligned.

[0067] The flat semiconductor element 11 has the silicone compound applied uniformly to the application surface 11c. The flat semiconductor element 11 has the silicone compound applied to the application surface 11c at a predetermined thickness. This prevents the silicone compound from becoming too thick. The thermal resistance does not increase near the contact surface of the flat semiconductor element 11. The device performance of the power conversion unit 10 is not impaired.

[0068] According to at least one of the embodiments described above, the use of the applicator does not increase the thickness of the silicone compound film, and the use of the applicator does not impair the device performance of the power conversion unit 10.

[0069] Although an embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. This embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as the inventions described in the claims and their equivalents.

[0070] As shown in FIG. 6, the storage container 26 may contain a porous body 27 such as a sponge inside. The porous body 27 is immersed in the silicone compound. The upper surface 27a of the porous body 27 is flat. The liquid surface of the silicone compound is located at the same height as the upper surface 27a of the porous body 27. The liquid surface of the silicone compound is located at a height slightly lower than the upper surface 27a of the porous body 27. The liquid surface of the silicone compound is located at a height lower than the upper surface 27a of the porous body 27.

[0071] To apply the silicone compound to the application surface 20a, the application jig 20 is inserted into the storage container 26. At this time, the application surface 20a is maintained facing the upper surface 27a. The application jig 20 is then lowered toward the storage container 26. The application surface 20a is brought into contact with the upper surface 27a.

[0072] Once the application surface 20a comes into contact with the upper surface 27a, the silicone compound is spread over the application surface 20a. The application jig 20 is rotated around the axis F1. The application jig 20 moves back and forth around the axis F1. At this time, the application surface 20a is kept from descending more than necessary from the upper surface 27a. At this time, the application surface 20a does not absorb the silicone compound. When a sufficient amount of silicone compound has been applied to the application surface 20a, the application surface 20a is separated from the upper surface 27a. The particles of the silicone compound are uniformly applied to the application surface 20a. The silicone compound can be applied to the other surface 11c of the flat semiconductor element 11 in the same manner.

[0073] Furthermore, the coating section 25 may be rhombic rather than square. In this case, the X-axis and the Y-axis may not be perpendicular to each other. In this case, the relative rotation between the coating surface 20a and the surface 11c to be coated may be larger than when the coating section 25 is square.

[0074] Furthermore, the application jig 20 can be attached to the tip of a robot hand to automate the application of the silicone compound. In this case, the robot hand can be driven to apply the silicone compound while holding the flat semiconductor element 11 from the radial side. [Explanation of symbols]

[0075] 10...Power conversion unit 11...Flat semiconductor element (flat pressure-welded element) 11c...Surface to be coated 20...Application jig 20a...coating surface 21...Long section groove (ditch) 21a...Side wall 22...Short section groove (groove) 22a...Side wall 25...Coating section 25a...Central application area

Claims

1. A coating jig for coating a particle-containing material on a surface to be coated of a flat pressure-contact element of a power conversion unit, The surface to be coated is a flat surface having a circular contour, a coating surface that conforms to the surface to be coated; an elastic body having a predetermined thickness from the coating surface, A groove dividing the application surface into a plurality of application sections Application jig.

2. The sidewalls of the grooves, which define the contours of the application sections, are perpendicular to the application surface. The applicator according to claim 1.

3. The grooves are formed to intersect with each other along the application surface. The applicator according to claim 1.

4. At least one of the intersecting grooves is formed so that both ends thereof are continuous to the contour of the application surface. The applicator according to claim 3.

5. The application section formed by being surrounded by the groove has a rectangular outline, The application sections are arranged in a row such that one of the sides intersecting in the outline of the application sections coincides with the adjacent application sections, and the other side does not coincide with the adjacent application sections. The applicator according to claim 1.

6. Among the application sections, a central application section located at the center of the application surface is formed longer along the row than the adjacent application sections. The applicator according to claim 5.

7. The application sections have the same contour shape except for the application sections that overlap the contour position of the application surface and the central application section. The applicator according to claim 6.

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