Semiconductor device and method for manufacturing semiconductor device

Abstract

A semiconductor device according to the present application includes a base plate having an upper surface and a back surface opposite to the upper surface, a ring-shaped groove being formed in the back surface; a substrate provided on the upper surface of the base plate; and a semiconductor chip provided on the upper surface of the substrate. The base plate has a convex curved portion curved upward from the upper surface. The groove is deeper as it is farther from a maximum curved portion in the convex curved portion where the curvature is the greatest.

Description

Technical Field

[0001] This invention relates to a semiconductor device and a method for manufacturing a semiconductor device. Background Technology

[0002] Patent Document 1 discloses a semiconductor device comprising: a semiconductor chip; an insulating substrate on which the semiconductor chip is bonded to a main surface; and a base on which another main surface of the insulating substrate is bonded to a main surface. A protrusion is provided on the other main surface of the base, and an annular groove is provided around the outer periphery of the protrusion. An annular sealing material made of an elastomer is inserted along the groove. A housing having an opening is configured such that the outer edge of the opening contacts the sealing material.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2015-73012 Summary of the Invention

[0004] In the case of a semiconductor device like that in Patent Document 1, a sealing material is sandwiched between a base plate and a cooler to prevent cooling water leakage by ensuring sufficient compression deformation. When the base plate is fixed to the cooler, the compression deformation of the sealing material is obtained by applying a load. However, if the load is not applied evenly around the entire circumference of the sealing material, the compression deformation will fluctuate, posing a risk of cooling water leakage. Furthermore, there is a risk of components breaking due to compression. In particular, depending on the warp shape of the contact surface between the base plate or the cooler and the sealing material, the gap between the base plate and the cooler becomes uneven, posing a risk of fluctuations in the compression deformation of the sealing material.

[0005] The purpose of this invention is to obtain a semiconductor device and a method for manufacturing the semiconductor device that can suppress fluctuations in the amount of extrusion deformation of the sealing material.

[0006] The semiconductor device disclosed in the first disclosure includes: a base plate having an upper surface and a back surface opposite to the upper surface, wherein an annular groove is formed on the back surface; a substrate disposed on the upper surface of the base plate; and a semiconductor chip disposed on the upper surface of the substrate. The base plate has a convex warp portion that warps in a manner that protrudes toward the upper surface, wherein the portion of the groove formed in the convex warp portion is deeper the further away from the largest warp portion in the convex warp portion.

[0007] The semiconductor device disclosed in the second disclosure includes: a base plate having an upper surface and a back surface opposite to the upper surface, wherein an annular groove is formed on the back surface; a substrate disposed on the upper surface of the base plate; and a semiconductor chip disposed on the upper surface of the substrate. The base plate has a concave warp portion that protrudes toward the back surface, and the depth of the portion of the groove formed in the concave warp portion is fixed.

[0008] The semiconductor device disclosed in the third disclosure includes: a base plate having an upper surface and a back surface opposite to the upper surface, wherein an annular groove is formed on the back surface; a substrate disposed on the upper surface of the base plate; a semiconductor chip disposed on the upper surface of the substrate; a sealing material contained in the groove; and a cooler fixed to the back surface of the base plate in such a way as to cover the groove, the base plate having a stress-generating portion that generates stress in a direction that causes the base plate to warp toward the back surface, and the depth of the portion of the groove formed in the stress-generating portion is fixed.

[0009] In the semiconductor device manufacturing method disclosed in the fourth disclosure, a substrate is mounted on the upper surface of a base plate, the base plate having the upper surface and a back surface opposite to the upper surface, an annular groove is formed on the back surface, a semiconductor chip is mounted on the upper surface of the substrate, the base plate has a concave warp portion that protrudes toward the back surface, and a cooler is fixed to the back surface of the base plate by covering the groove with a sealing material contained therein, thereby reducing the warp of the concave warp portion, and the depth of the portion of the groove formed in the concave warp portion is fixed.

[0010] The effects of the invention

[0011] In the semiconductor device and its manufacturing method according to the present invention, the depth of the groove is set in accordance with the warping direction of the base plate. Therefore, fluctuations in the amount of extrusion deformation of the sealing material can be suppressed. Attached Figure Description

[0012] Figure 1 This is a cross-sectional view of the semiconductor device according to Embodiment 1.

[0013] Figure 2 This is a bottom view of the base plate according to Embodiment 1.

[0014] Figure 3 This is a cross-sectional view of the base plate in Embodiment 1 when it is not warped.

[0015] Figure 4 This is a cross-sectional view of the base plate in the embodiment 1, showing a warped state.

[0016] Figure 5 This is a cross-sectional view showing the base plate according to Embodiment 1 installed in the cooler.

[0017] Figure 6 This is a cross-sectional view of the base plate in embodiment 2 without warping.

[0018] Figure 7This is a cross-sectional view of the base plate in embodiment 2, showing a warped state.

[0019] Figure 8 This is a cross-sectional view showing the base plate according to Embodiment 2 installed in the cooler.

[0020] Figure 9 This is a cross-sectional view of the base plate in embodiment 3 without warping.

[0021] Figure 10 This is a cross-sectional view of the base plate in the embodiment 3, showing a warped state.

[0022] Figure 11 This is a cross-sectional view of the base plate in embodiment 4 without warping.

[0023] Figure 12 This is a cross-sectional view of the base plate in embodiment 4, showing a warped state.

[0024] Figure 13 This is a cross-sectional view of the base plate in embodiment 5 when it is not warped.

[0025] Figure 14 This is a cross-sectional view of the base plate in embodiment 5 under a warped state.

[0026] Figure 15 This is a cross-sectional view of the base plate in embodiment 6 without warping.

[0027] Figure 16 This is a cross-sectional view of the base plate in embodiment 6, showing a warped state.

[0028] Figure 17 This is a cross-sectional view showing the base plate according to Embodiment 6 installed in the cooler.

[0029] Figure 18 This is a cross-sectional view of the base plate in embodiment 7 without warping.

[0030] Figure 19 This is a cross-sectional view of the base plate in embodiment 7 under a warped state.

[0031] Figure 20 This is a cross-sectional view of the base plate in embodiment 8 without warping.

[0032] Figure 21 This is a cross-sectional view of the base plate in the case of embodiment 8, showing a warped state.

[0033] Figure 22This is a cross-sectional view of the base plate in embodiment 9 without warping.

[0034] Figure 23 This is another cross-sectional view of the base plate in the embodiment 9, in a state where no warping occurs.

[0035] Figure 24 This is a cross-sectional view of the base plate in the case of embodiment 9, in a warped state.

[0036] Figure 25 These are other cross-sectional views of the base plate in the case of embodiment 9, where warping has occurred.

[0037] Figure 26 This is a cross-sectional view showing the base plate according to Embodiment 9 installed in the cooler.

[0038] Figure 27 This is another cross-sectional view showing the base plate according to Embodiment 9 installed in the cooler. Detailed Implementation

[0039] The semiconductor device and its manufacturing method according to each embodiment will be described with reference to the accompanying drawings. Identical or corresponding structural elements are labeled with the same reference numerals, and sometimes repeated descriptions are omitted.

[0040] Implementation Method 1

[0041] Figure 1 This is a cross-sectional view of the semiconductor device 100 according to Embodiment 1. The semiconductor device 100 includes a base plate 1, a substrate 2 disposed on the upper surface of the base plate 1, and a semiconductor chip 3 disposed on the upper surface of the substrate 2. Figure 2 This is a bottom view of the base plate 1 according to Embodiment 1. The base plate 1 has an upper surface and a back surface opposite to the upper surface, and an annular groove 5 is formed on the back surface. The groove 5 is quadrilateral when viewed from above.

[0042] Sealing material 4 is contained in the groove 5. The cooler 7 is fixed to the back of the base plate 1. The outer edge of the cooler 7 covers the groove 5. The cooler 7 retains cooling water 6. The base plate 1 is fastened to the cooler 7 by fastening components 8. By fixing the base plate 1 to the cooler 7 via the sealing material 4, the cooling water 6 can be sealed.

[0043] Semiconductor chip 3 is, for example, a power semiconductor chip. Semiconductor chip 3 is, for example, an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), or a diode. Power semiconductor chips have the potential to reach high temperatures during operation, so ensuring high heat dissipation is important. Semiconductor chip 3 is, for example, formed of Si. Semiconductor chip 3 can also be formed of a wide-bandgap semiconductor. Wide-bandgap semiconductors are, for example, silicon carbide, gallium nitride-based materials, or diamond. When semiconductor chip 3 is formed of a wide-bandgap semiconductor, it can operate at high temperatures. Therefore, ensuring high heat dissipation is particularly important. Figure 1 Two semiconductor chips 3 are shown, but the semiconductor device 100 may have one or more semiconductor chips 3.

[0044] Substrate 2 is, for example, an insulating substrate. Substrate 2 comprises a surface circuit pattern 2a, a ceramic substrate 2b, and a back circuit pattern 2c. The ceramic substrate 2b is formed, for example, of ceramics such as Al2O3, AlN, or Si3N4. The surface circuit pattern 2a and the back circuit pattern 2c are, for example, formed of a metal with Cu as the main component. The surface circuit pattern 2a and the back circuit pattern 2c are respectively formed on the upper surface and the back surface of the ceramic substrate 2b. The surface circuit pattern 2a is selectively formed on the upper surface of the ceramic substrate 2b. Thus, a circuit is formed on the upper surface of the ceramic substrate 2b.

[0045] Furthermore, at least one back electrode of the semiconductor chip 3 is bonded to the upper surface of the surface circuit pattern 2a. The back electrode is, for example, a collector electrode. The semiconductor chip 3 is connected to the surface circuit pattern 2a via a bonding material, such as a lead-free solder like Sn-Ag. Various wirings are formed on the surface electrodes of the semiconductor chip 3 using bonding wires or metal plates. The surface electrodes are, for example, emitter electrodes or gate electrodes. With this structure, the desired circuitry is formed in the semiconductor device 100. Additionally, the semiconductor chip 3 is protected by an outer frame, cover, encapsulating resin, etc. (not shown).

[0046] The base plate 1 is plate-shaped. It is formed of a metallic material such as copper or a copper alloy. The circuit pattern 2c on the back side of the substrate 2 is bonded to the base plate 1 via a bonding material. The bonding material can be, for example, a lead-free solder such as Sn-Ag. This structure efficiently conducts heat generated from the semiconductor chip 3 during operation of the semiconductor device 100 to the cooling water 6, ensuring high heat dissipation characteristics. Fins or other protrusions can also be provided on the back side of the base plate 1. This increases the contact area between the base plate 1 and the cooling water 6, further improving heat dissipation characteristics.

[0047] The cooler 7 is box-shaped and has an opening. The cooler 7 supplies cooling water 6 to the semiconductor device 100 and has the function of retaining the cooling water 6. The cooler 7 is formed of a metallic material such as Al or an Al alloy. This ensures the durability of the cooler 7 in retaining the cooling water 6. Additionally, the cooler 7 has a supply port (not shown) and a discharge port (not shown) for circulating the cooling water 6 between the cooler 7 and an external heat dissipation device.

[0048] The sealing material 4 is, for example, a ring-shaped elastomer formed of rubber. The sealing material 4 is, for example, an O-ring. The sealing material 4 is inserted into the groove 5 and positioned between the base plate 1 and the cooler 7. Through holes 9 are formed at the four outer corners of the base plate 1 compared to the groove 5. Fastening components 8, such as bolts, are inserted into the through holes 9. This holds the base plate 1 in a state of being pressed against the cooler 7. At this time, the sealing material 4 applies elastic force to the portion of the base plate 1 with the groove 5 and the cooler 7, and fits them tightly. Thus, the gap between the base plate 1 and the cooler 7 can be completely filled by the sealing material 4. Therefore, leakage of cooling water 6 to the outside can be prevented. This cooling method is also called direct cooling.

[0049] Next, as a specific example of the construction of the base plate 1, the base plate 1a with the groove 5a formed will be described. Figure 3 This is a cross-sectional view of the base plate 1a in the embodiment 1, in a state where no warping occurs. Figure 4 This is a cross-sectional view of the base plate 1a in the embodiment 1, which is in a warped state. Figure 3 , Figure 4 A cross-section of the base plate 1a is shown along one of the four sides of the groove 5a. The depth of the groove 5a at the base plate 1a increases as it moves away from the center of one side of the groove 5a.

[0050] exist Figure 3 In the un-warped state before assembly shown, the depth of groove 5a is uneven. In contrast, as... Figure 4 As shown, due to heat load during assembly, the base plate 1a warps in a manner that protrudes towards the upper surface 11. That is, the base plate 1a has a convex warped portion 13 that warps towards the upper surface 11. Regarding the portion of the groove 5a formed at the convex warped portion 13, the greater the warping, the deeper it is, further away from the largest warped portion 14 in the convex warped portion 13. Here, the depth of the groove 5a refers to the height from the back surface 12 of the base plate 1a to the bottom 51a of the groove 5a. Furthermore, the largest warped portion 14 is the most convex portion of the upper surface 11 of the base plate 1a. In this embodiment, the largest warped portion 14 is formed at the center of one side of the groove 5a. At the portion of the groove 5a formed at the convex warped portion 13, the thickness between the bottom 51a of the groove 5a and the upper surface 11 of the base plate 1a decreases further away from the largest warped portion 14.

[0051] Figure 5 This is a cross-sectional view showing the base plate 1a according to Embodiment 1 installed in the cooler 7. By warping the base plate 1a so that it protrudes towards the upper surface 11, the difference in depth of the groove 5a is offset. That is, the height from the cooler 7 to the bottom 51a of the groove 5a can be made uniform. Therefore, fluctuations in the amount of extrusion deformation of the sealing material 4 can be suppressed.

[0052] Here, the base plate 1a is fixed to the cooler 7 at its end. Therefore, when the base plate 1a is fixed to the cooler 7, the force to correct warping is difficult to apply. Therefore, in Figure 5 Even with the base plate 1a mounted on the cooler 7 as shown, it can still maintain... Figure 4 The shape of the groove 5a shown is such that fluctuations in the amount of extrusion deformation of the sealing material 4 can be suppressed. This, in turn, can suppress leakage of the cooling water 6 and compression cracking of components.

[0053] For example, assuming the warping shape of the base plate is not considered, the depth of the groove is set to be deeper closer to the end of the base plate. In this case, depending on the direction of warping, there may be portions where the sealing material is under-deformed or over-deformed. In portions with insufficient deformation, cooling water leakage may occur. Conversely, in portions with excessive deformation, compression fracture of the component may occur. In this embodiment, the depth of the groove 5 is set corresponding to the warping direction of the base plate 1. Therefore, fluctuations in the amount of deformation of the sealing material 4 can be reliably suppressed.

[0054] Furthermore, the bottom 51a of the portion formed in the convex warp 13 within the groove 5a is formed by a flat surface. This allows the sealing material 4 to be uniformly compressed and deformed through the flat surface. Additionally, as... Figure 4 As shown, the bottom 51a of the groove 5a, which is in a warped state, can be formed by a single plane. This allows the sealing material 4 to be further deformed more uniformly.

[0055] Furthermore, the bottom 51a of the warped tank 5a may not be a flat plane, and the height from the cooler 7 to the bottom 51a of the tank 5a may not be completely uniform. As long as leakage of cooling water can be prevented, the height from the cooler 7 to the bottom 51a of the tank 5a can vary depending on the location.

[0056] Figure 4 , 5The structure shown can be formed on at least one of the four sides of the groove 5a. That is, the deeper the groove 5a is formed on at least one side of the convex warp portion 13, the further away from the maximum warp portion 14 it is. In addition, the groove 5a can also be polygonal, elliptical or circular when viewed from above.

[0057] Furthermore, the method of fixing the base plate 1 to the cooler 7 is not limited to fastening with bolts. The base plate 1 and the cooler 7 can also be interlocked. The base plate 1 can be fixed while being pressed against the cooler 7.

[0058] These modifications can be appropriately applied to the semiconductor device and the method for manufacturing the semiconductor device according to the following embodiments. Furthermore, since there are many similarities with Embodiment 1, the semiconductor device and the method for manufacturing the semiconductor device according to the following embodiments will be described focusing on the differences from Embodiment 1.

[0059] Implementation Method 2

[0060] Figure 6 This is a cross-sectional view of the base plate 1b in embodiment 2 without warping. Figure 7 This is a cross-sectional view of the base plate 1b in Embodiment 2, showing a warped state. In this embodiment, the structure and warping direction of the base plate 1b differ from those in Embodiment 1. The depth of the groove 5b in the base plate 1b is fixed in this embodiment.

[0061] exist Figure 6 As shown, in the unwarped state before assembly, the depth of groove 5b is uniform. In contrast, as... Figure 7 As shown, due to heat load during assembly, the base plate 1b warps in a manner that protrudes towards the back surface 12. That is, the base plate 1b has a concave warped portion 15 that warps towards the back surface 12. The depth of the portion of the groove 5b formed in the concave warped portion 15 is fixed.

[0062] Next, the manufacturing method of the semiconductor device according to this embodiment will be described. First, a semiconductor chip 3 is mounted on the upper surface of a substrate 2. Additionally, the substrate 2 is mounted on the upper surface of a base plate 1b. Next, with the base plate 1b having a concave warp portion 15 and the sealing material 4 contained in a groove 5b, a cooler 7 is fixed to the back surface 12 of the base plate 1b to cover the groove 5b. This reduces the warping of the concave warp portion 15 compared to before fixing the cooler 7. Furthermore, the assembly order of the substrate 2, semiconductor chip 3, base plate 1b, sealing material 4, and cooler 7 can also be changed.

[0063] Figure 8This is a cross-sectional view showing the base plate 1b according to Embodiment 2 installed in the cooler 7. The base plate 1b is fixed to the cooler 7 at its ends. Therefore, when the base plate 1b is fixed to the cooler 7, the force for correcting warping is easily applied. Therefore, in Figure 8 As shown, with the base plate 1b installed on the cooler 7, the groove 5b is aligned with the unwarped surface. Figure 6 The shapes shown are approximately identical. Therefore, the height from the cooler 7 to the bottom 51b of the tank 5b can be made uniform, and fluctuations in the amount of extrusion deformation of the sealing material 4 can be suppressed.

[0064] exist Figure 8 In the shown state, stress is generated in the base plate 1b in the direction that causes the base plate 1b to warp toward the back surface 12. That is, the base plate 1b has a stress-generating portion 16, which generates stress in the direction that causes the base plate 1b to warp toward the back surface 12. The depth of the portion of the groove 5b formed in the stress-generating portion 16 is fixed.

[0065] In this embodiment, the bottom 51b of the groove 5b is flat. However, it is not limited to this; the bottom 51b of the groove 5b may also be curved or have concave and convex surfaces. In addition, when the base plate 1b is installed on the cooler 7, the height from the cooler 7 to the bottom 51b of the groove 5b may not be completely uniform.

[0066] Implementation Method 3

[0067] Figure 9 This is a cross-sectional view of the base plate 1c in embodiment 3 without warping. Figure 10 This is a cross-sectional view of the base plate 1c according to Embodiment 3 in a warped state. The base plate 1c has a convex warped portion 13. Similar to Embodiment 1, the groove 5c of the base plate 1c is polygonal when viewed from above. Furthermore, similar to Embodiment 1, the groove 5c is deeper closer to the end of at least one side of the convex warped portion 13. Also, the depth of the groove 5c at at least one side of the convex warped portion 13 is symmetrical with respect to the center 10 of that side. The angle θ1 representing the change in depth of the groove 5c is the same on both sides of the center 10. Angle θ1 is the angle formed between the back surface 12 of the base plate 1c and the bottom 51c of the groove 5c in cross-section.

[0068] According to this structure, at the center 10 of the edge of the groove 5c of the base plate 1c, which is prone to become the maximum warping part 14, the sealing material 4 can be reliably squeezed and deformed during assembly with the cooler 7.

[0069] Implementation Method 4

[0070] Figure 11This is a cross-sectional view of the base plate 1d in embodiment 4, in a state where no warping has occurred. Figure 12 This is a cross-sectional view of the base plate 1d in embodiment 4, showing a warped state. In this embodiment, the shape of the groove 5d in the base plate 1d differs from that in embodiment 3. The portion of the groove 5d formed at the convex warped portion 13 becomes deeper the further away from the center 10. The depth of the groove 5d is symmetrical with respect to the center 10. The bottom 51d of the portion of the groove 5d formed at the convex warped portion 13 is formed by a curved surface. The shape of the bottom 51d is the same on both sides of the center 10.

[0071] In this embodiment, the groove 5d is shallower the closer it is to the center 10. Therefore, at the center 10 of the edge of the groove 5d on the base plate 1d, which is prone to become the maximum warping portion 14, the sealing material 4 can be reliably squeezed and deformed during assembly with the cooler 7.

[0072] In addition, such as Figure 12 As shown, in this embodiment, the height from the cooler 7 to the bottom 51d of the groove 5d is not completely uniform. However, in this embodiment, by warping the base plate 1d so as to bulge towards the upward surface 11, the difference in the depth of the groove 5d is also offset. Therefore, fluctuations in the amount of extrusion deformation of the sealing material 4 can be suppressed.

[0073] Implementation Method 5

[0074] Figure 13 This is a cross-sectional view of the base plate 1e in embodiment 5, in a state where no warping has occurred. Figure 14 This is a cross-sectional view of the base plate 1e in embodiment 5, showing a warped state. In this embodiment, the shape of the groove 5e in the base plate 1e differs from that in embodiment 3. The portion of the groove 5e formed at the convex warped portion 13 is deeper the further away from the center 10. The depth of the groove 5e is symmetrical with respect to the center 10. The bottom 51e of the portion of the groove 5e formed at the convex warped portion 13 is stepped.

[0075] In this embodiment, the groove 5e is shallower the closer it is to the center 10. Therefore, at the center 10 of the edge of the groove 5e of the base plate 1c, which is prone to become the maximum warping portion 14, the sealing material 4 can be reliably squeezed and deformed during assembly with the cooler 7.

[0076] Implementation Method 6

[0077] Figure 15 This is a cross-sectional view of the base plate 1f in embodiment 6 in a state where no warping occurs. Figure 16 This is a cross-sectional view of the base plate 1f in embodiment 6, showing a warped state. Figure 17This is a cross-sectional view showing the base plate 1f according to Embodiment 6 installed in the cooler 7. In this embodiment, the shape of the groove 5f of the base plate 1f is different from that of Embodiment 1. The base plate 1f has a convex warped portion 13. Similar to Embodiment 1, the groove 5f of the base plate 1f is polygonal when viewed from above. Regarding the portion of the groove 5f formed at the convex warped portion 13, it becomes deeper the further away from the maximum warped portion 14. In addition, the bottom 51f of the groove 5f is formed by a flat surface.

[0078] In this embodiment, the maximum warp portion 14 is located at a position offset from the center 10 of one side of the groove 5f formed by the convex warp portion 13 in the direction along that side. On the shorter side of one side of the groove 5f formed by the convex warp portion 13, the distance from the maximum warp portion 14 to the end of that side is greater than that on the longer side, when the groove 5f moves a certain distance away from the maximum warp portion 14. That is, θ2 > θ3. At both ends of one side of the groove 5f formed by the convex warp portion 13, the depth of the groove 5f is the same.

[0079] In this way, the depth of the groove 5f is set according to the shape of the protruding warp of the base plate 1f, such as... Figure 17 As shown, the height from the cooler 7 to the bottom 51f of the tank 5f can be made uniform. Therefore, fluctuations in the amount of extrusion deformation of the sealing material 4 can be suppressed.

[0080] Implementation Method 7

[0081] Figure 18 This is a cross-sectional view of the base plate 1g in embodiment 7, in a state where no warping has occurred. Figure 19 This is a cross-sectional view of the base plate 1g in embodiment 7, showing a warped state. In this embodiment, the shape of the groove 5g in the base plate 1g differs from that in embodiment 6. The bottom 51g of the groove 5g is formed by a curved surface.

[0082] Similar to Embodiment 6, the maximum warping portion 14 of the base plate 1g is located at a position offset from the center 10 of one side of the groove 5g formed by the convex warping portion 13 in the direction along that side. On the side of the groove 5g formed by the convex warping portion 13, the shorter side (distance from the maximum warping portion 14 to the end of that side) exhibits a greater variation in depth of the groove 5g when it moves away from the maximum warping portion 14 by a certain distance compared to the longer side. That is, the shorter side (distance from the maximum warping portion 14 to the end of the edge of the groove 5g) has a greater curvature than the longer side (distance from the maximum warping portion 14 to the end of the edge of the groove 5g).

[0083] In this embodiment, by setting the depth of the groove 5g in accordance with the protruding warp shape of the base plate 1g, the sealing material 4 can be reliably squeezed and deformed at the maximum warp portion 14.

[0084] Implementation Method 8

[0085] Figure 20 This is a cross-sectional view of the base plate 1h in embodiment 8, in which no warping occurs. Figure 21 This is a cross-sectional view of the base plate 1h in embodiment 8, showing a warped state. In this embodiment, the shape of the groove 5h in the base plate 1h differs from that in embodiment 6. The bottom 51h of the groove 5h is stepped.

[0086] Similar to Embodiment 6, the maximum warping portion 14 of the base plate 1h is located at a position offset from the center 10 of one side of the groove 5h formed by the convex warping portion 13 in the direction along that side. On the shorter side of the groove 5h formed by the convex warping portion 13, the distance from the maximum warping portion 14 to the end of that side is greater than that on the longer side, when the groove 5h moves away from the maximum warping portion 14 by a certain distance.

[0087] In this embodiment, by setting the depth of the groove 5h in accordance with the shape of the protruding warp of the base plate 1h, the sealing material 4 can be reliably squeezed and deformed at the maximum warp portion 14.

[0088] Implementation Method 9

[0089] Figure 22 This is a cross-sectional view of the base plate 1i in embodiment 9, in a state where no warping has occurred. Figure 23 This is another cross-sectional view of the base plate 1i in Embodiment 9 without warping. In this embodiment, the shape of the groove 5i of the base plate 1i is different from that in Embodiment 1. Figure 22 , 23 The grooves 5j and 5k shown each constitute one side of the groove 5i in this embodiment. The depth of the groove 5j is fixed. The groove 5k becomes deeper the further away from the center of the groove 5k is along its length.

[0090] Figure 24 This is a cross-sectional view of the base plate 1i in embodiment 9, showing a warped state. Figure 25This is another cross-sectional view of the base plate 1i according to Embodiment 9 in a warped state. A groove 5j of fixed depth is formed in the concave warped portion 15 of the base plate 1i. In addition, a groove 5k is formed in the convex warped portion 13. The groove 5k becomes deeper the further away from the maximum warped portion 14. Thus, the convex warped portion 13 and the concave warped portion 15 coexist in the base plate 1i. The depth of the groove 5j is the same as the two deepest ends of the groove 5k.

[0091] Figure 26 This is a cross-sectional view showing the base plate 1i according to Embodiment 9 installed in the cooler 7. The base plate 1i is fixed to the cooler 7 at its ends. At the concave warp portion 15, when the base plate 1i is fixed to the cooler 7, the force for correcting warp easily takes effect. Therefore, in Figure 26 In the state shown, groove 5j is in the same position as the one that has not warped. Figure 22 The shapes shown are approximately identical. Therefore, the height from the bottom of the cooler 7 to the bottom of the tank 5j can be made uniform, and fluctuations in the amount of extrusion deformation of the sealing material 4 can be suppressed.

[0092] exist Figure 26 In the state shown, the portion of the base plate 1i in which the groove 5j is formed generates stress in the direction that causes the base plate 1i to warp toward the back surface 12. The groove 5j is a stress-generating part 16 in the base plate 1i that generates stress in the direction that causes the base plate 1i to warp toward the back surface 12.

[0093] Figure 27 This is another cross-sectional view showing the base plate 1i according to Embodiment 9 installed in the cooler 7. At the warped portion 13, when the base plate 1i is fixed to the cooler 7, the force to correct the warping is difficult to apply. Therefore, in Figure 27 It can also maintain the state shown. Figure 25 The shape of the groove 5k shown is such that the height from the cooler 7 to the bottom of the groove 5k is uniform, and fluctuations in the amount of extrusion deformation of the sealing material 4 can be suppressed.

[0094] In this embodiment, even with a structure where different warp shapes coexist, the height from the cooler 7 to the bottom of the groove 5i can be made uniform. Therefore, fluctuations in the amount of extrusion deformation of the sealing material 4 throughout its circumference can be suppressed.

[0095] The technical features described in each embodiment may also be used in combination as appropriate.

[0096] Explanation of the label

[0097] 1. 1a-1i base plate, 2 substrate, 2a surface circuit pattern, 2b ceramic substrate, 2c back circuit pattern, 3 semiconductor chip, 4 sealing material, 5. 5a-5k groove, 6 cooling water, 7 cooler, 8 fastening component, 9 through hole, 10 center, 11 upper surface, 12 back side, 13 convex warp portion, 14 maximum warp portion, 15 concave warp portion, 16 stress generating portion, 51a-51h bottom, 100 semiconductor device.

Claims

1. A semiconductor device, characterized in that, have: A base plate having an upper surface and a back surface opposite to the upper surface, wherein an annular groove is formed on the back surface; A substrate disposed on the upper surface of the base plate; as well as A semiconductor chip is disposed on the upper surface of the substrate. The base plate has a warped portion that protrudes toward the upper surface. Regarding the portion of the groove formed in the convex warp portion, the deeper the convex warp portion is, the further away from the largest warp portion in the convex warp portion.

2. The semiconductor device according to claim 1, characterized in that, The groove is polygonal when viewed from above. With respect to at least one side of the convex warp in the groove, the groove becomes deeper the further away from the maximum warp.

3. The semiconductor device according to claim 1 or 2, characterized in that, The thickness between the bottom of the groove and the upper surface of the base plate is smaller the further away from the maximum warping portion in the portion formed in the groove.

4. The semiconductor device according to any one of claims 1 to 3, characterized in that, The groove is polygonal when viewed from above. With respect to at least one side of the convex warp in the groove, the depth of the groove is symmetrical with respect to the center of the side.

5. The semiconductor device according to any one of claims 1 to 3, characterized in that, The groove is polygonal when viewed from above. The maximum warpage is located at a position offset from the center of one side of the convex warpage formed in the groove in a direction along that side. On the shorter side of the side, from the maximum warping portion to the end of the side, the depth of the groove varies more significantly when it moves away from the maximum warping portion by a certain distance compared to the longer side.

6. The semiconductor device according to any one of claims 1 to 5, characterized in that, The bottom of the portion of the groove formed in the convex warp is formed by a flat surface.

7. The semiconductor device according to any one of claims 1 to 5, characterized in that, The bottom of the portion of the groove formed in the convex warp is formed by a curved surface.

8. The semiconductor device according to any one of claims 1 to 5, characterized in that, The bottom of the portion of the groove formed in the convex warp is stepped.

9. The semiconductor device according to any one of claims 1 to 8, characterized in that, A portion of the groove has a fixed depth, equal to the deepest part of the groove formed in the convex warp portion.

10. The semiconductor device according to claim 9, characterized in that, The fixed-depth portion of the groove is formed in the base plate as a stress-generating part that generates stress in the direction that causes the base plate to warp in a manner that bulges toward the rear side.

11. The semiconductor device according to any one of claims 1 to 10, characterized in that, have: A sealing material is contained in the groove; as well as A cooler is fixed to the back side of the base plate in such a way that it covers the groove.

12. The semiconductor device according to claim 9, characterized in that, The fixed-depth portion of the groove is formed in the base plate by a concave warp that protrudes toward the rear side.

13. A semiconductor device, characterized in that, have: A base plate having an upper surface and a back surface opposite to the upper surface, wherein an annular groove is formed on the back surface; A substrate disposed on the upper surface of the base plate; as well as A semiconductor chip is disposed on the upper surface of the substrate. The base plate has a concave warp portion that warps in a manner that protrudes toward the rear side. The depth of the portion of the groove formed in the concave warp is fixed.

14. A semiconductor device, characterized in that, have: A base plate having an upper surface and a back surface opposite to the upper surface, wherein an annular groove is formed on the back surface; A substrate disposed on the upper surface of the base plate; A semiconductor chip is disposed on the upper surface of the substrate; A sealing material is contained in the groove; as well as A cooler, which is fixed to the back side of the base plate in a manner that covers the groove. The base plate has a stress-generating portion that generates stress in the direction that causes the base plate to warp in a manner that bulges towards the rear side. The depth of the portion of the groove formed at the stress-generating part is fixed.

15. The semiconductor device according to any one of claims 1 to 14, characterized in that, The semiconductor chip is formed from a wide-bandgap semiconductor.

16. The semiconductor device according to claim 15, characterized in that, The wide-bandgap semiconductor is silicon carbide, gallium nitride, or diamond.

17. A method for manufacturing a semiconductor device, characterized in that, A substrate is mounted on the upper surface of a base plate, the base plate having the upper surface and a back surface opposite to the upper surface, wherein an annular groove is formed on the back surface. A semiconductor chip is mounted on the upper surface of the substrate. The base plate has a concave warp portion that protrudes towards the rear side. With the sealing material contained in the groove, the cooler is fixed to the rear side of the base plate by covering the groove, thereby reducing the warp of the concave warp portion. The depth of the portion of the groove formed in the concave warp is fixed.

Images