Semiconductor device

Abstract

To provide a semiconductor device having high voltage-withstanding.SOLUTION: A semiconductor device includes a semiconductor element, a first conductor, a first electrode, a second conductor, a second electrode, and a cover. The semiconductor element includes a first electrode pad that spreads along a first face, includes a first surface, a second surface facing the first surface, and a third surface extending between an end of the first surface and an end of the second surface, and is provided in a region including the first surface, and a second electrode pad provided in a region including the second surface. The first conductor contacts the first electrode pad. The first electrode contacts the first conductor. The second conductor contacts the second electrode pad. The second electrode contacts the second conductor. The cover is a resin cover including a first portion, a second portion, and a third portion. The first portion covers the third surface. The second portion is connected to the first portion and faces the first surface. The third portion is connected to the first portion, faces the second surface, and interposes the semiconductor element together with the second portion.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] Known examples of power semiconductor devices include an IGBT (Insulated Gate Bipolar Transistor) and an IEGT (Injection Enhanced Gate Transistor). The chips of these semiconductor devices include a collector electrode pad on one of two opposing surfaces and an emitter electrode pad on the other. Electrodes are attached to each of the collector electrode pad and the emitter electrode pad. Since high voltages are applied to power semiconductor devices, they are required to be able to withstand the application of high voltages. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2012 / 133098 Brochure [Patent Document 2] Japanese Patent Application Publication No. 6-224235 [Patent Document 3] Patent No. 7203214 Summary of the Invention [Problem to be solved by the invention]

[0004] A semiconductor device having high breakdown voltage is provided. [Means for solving the problem]

[0005] A semiconductor device according to an embodiment includes a semiconductor element, a first conductor, a first electrode, a second conductor, a second electrode, and a cover. The semiconductor element extends along a first surface, includes a first surface, a second surface facing the first surface, and a third surface extending between an end of the first surface and an end of the second surface, and includes a first electrode pad provided in a region including the first surface, and a second electrode pad provided in a region including the second surface. The first electrode contacts the first electrode pad. The first electrode contacts the first conductor. The second conductor contacts the second electrode pad. The second electrode contacts the second conductor. The cover is a resin cover including a first portion, a second portion, and a third portion. The first portion covers the third surface. The second portion is connected to the first portion and faces the first surface. The third portion is connected to the first portion, faces the second surface, and sandwiches the semiconductor element together with the second portion. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 shows an example of the structure of a conversion device including the semiconductor device of the first embodiment. [Diagram 2] FIG. 2 shows an example of a cross-sectional structure of a semiconductor module including the semiconductor device of the first embodiment. [Diagram 3] FIG. 3 shows an example of a planar structure of the semiconductor device according to the first embodiment. [Figure 4] FIG. 4 shows an example of a planar structure of the semiconductor device according to the first embodiment. [Diagram 5] FIG. 5 shows an example of a cross-sectional structure of the semiconductor device of the first embodiment. [Figure 6] FIG. 6 shows an example of a cross-sectional structure of the semiconductor device of the first embodiment. [Figure 7] FIG. 7 shows an example of a cross-sectional structure of the semiconductor device of the first embodiment. [Figure 8] FIG. 8 shows a part of the manufacturing process of the semiconductor device of the first embodiment. [Figure 9] FIG. 9 shows a part of the manufacturing process of the semiconductor device of the first embodiment. [Figure 10] FIG. 10 shows an example of a cross-sectional structure of a semiconductor device according to a modified example of the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, embodiments will be described with reference to the drawings. The drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc. may differ from the actual ones. Furthermore, the drawings may include parts in which the relationship and ratio of dimensions differ from each other.

[0008] Hereinafter, an embodiment will be described using an XYZ Cartesian coordinate system. The positive direction of the vertical axis of the figure may be referred to as the upper side, and the negative direction as the lower side. The positive direction of the horizontal axis of the figure may be referred to as the right side, and the negative direction as the left side. That is, in a plan view showing an XY plane (XY plane view (hereinafter the same)), the upper side refers to the +Y direction, the lower side refers to the -Y direction, the right side refers to the +X direction, and the left side refers to the -X direction. In an XZ plane view observed in the +Y direction, the upper side refers to the +Z direction, the lower side refers to the -Z direction, the right side refers to the +X direction, and the left side refers to the -X direction.

[0009] 1. First embodiment 1.1.Configuration (Structure) FIG. 1 shows an example of the structure of a converter including the semiconductor device of the first embodiment. The converter 100 converts, for example, electric power. As shown in FIG. 1, the converter 100 includes a housing including a bottom 101, a side 102, and an upper portion 103. The housing has a space therein. The converter 100 also includes, inside the housing, a support 105, a plurality of cooling fins 106, a support 107, a spring 108, and a plurality of semiconductor modules 110. FIG. 1 shows an example of three semiconductor modules 110.

[0010] The support 105 is made of an insulator and is located on the upper surface of the bottom 101. A plurality of cooling fins 106 and a plurality of semiconductor modules 110 are alternately located on the upper surface of the support 105. That is, one semiconductor module 110 is placed on the upper surface of one cooling fin 106, another cooling fin is placed on the upper surface of the semiconductor module 110, and similarly, further semiconductor modules 110 and cooling fins 106 are placed. Two semiconductor modules 110 aligned in the +Z direction are electrically connected to each other.

[0011] The support 107 is made of an insulating material and is located on the upper surface of the uppermost cooling fin 106. The spring 108 is located on the upper surface of the support 107 and is in contact with the lower surface of the upper portion 103 at its upper surface.

[0012] 2 shows an example of a cross-sectional structure of a semiconductor module including the semiconductor device of the first embodiment. As shown in FIG. 2, the semiconductor module 110 includes a plurality of semiconductor devices 1, a plurality of conductors 131, a plurality of terminal boards 132, and external electrodes 135 and 136.

[0013] The semiconductor devices 1 are arranged at intervals on the upper surface of the external electrode 135. The semiconductor device 1 includes a semiconductor element 3, an emitter electrode 4, and a collector electrode 5.

[0014] The semiconductor element 3 is an element formed on a substrate substantially composed of a semiconductor. In this specification, the term "substantially" means that the content expressed by the term "substantially" does not require strict literal accuracy and includes errors due to unavoidable factors. Examples of the semiconductor element 3 include an IGBT and an IEGT.

[0015] The collector electrode 5 is a conductive member such as a metal. The collector electrode 5 is located on the upper surface of the external electrode 135. The semiconductor element 3 is located on the upper surface of the collector electrode 5.

[0016] The emitter electrode 4 is a conductive member such as a metal. The emitter electrode 4 is located on the upper surface of the semiconductor element 3.

[0017] The conductor 131 is located on the upper surface of the semiconductor element 3, and its lower surface contacts a gate electrode pad 6 (not shown) of the semiconductor element 3. The terminal plate 132 contacts the upper surface of the conductor 131 on its lower surface.

[0018] The external electrode 135 contains copper (Cu) or is substantially made of copper. The lower surface of the external electrode 136 contacts the upper surfaces of the multiple semiconductor elements 3. The external electrode 136 contains copper or is substantially made of copper.

[0019] 3 and 4 show an example of a planar structure of the semiconductor device of the first embodiment. Fig. 3 shows the semiconductor device 1 observed in the -Z direction. Fig. 4 shows the semiconductor device 1 observed in the +Z direction.

[0020] 3 and 4, the semiconductor device 1 extends along the XY plane. The semiconductor element 3 has a quadrilateral shape, for example a rectangular shape, along the XY plane. In addition to including the semiconductor element 3, the emitter electrode 4, and the collector electrode 5 as described above with reference to FIG. 2, the semiconductor device 1 also includes a cover 7. The semiconductor element 3 further includes a gate electrode pad 6.

[0021] The emitter electrode 4 has a size that fits inside the edge of the semiconductor element 3 along the XY plane. The emitter electrode 4 has a quadrilateral shape with the corners of the quadrilateral cut out along the XY plane. The emitter electrode 4 has, for example, a rectangular shape with the corners of the rectangle cut out in a rectangular shape along the XY plane. The emitter electrode 4 contacts an emitter electrode pad 31 (not shown) of the semiconductor element 3.

[0022] The emitter electrode 4 includes one or more of molybdenum (Mo), ruthenium (Ru), tungsten (W), iron (Fe), copper (Cu), cobalt (Co), nickel (Ni), and palladium (Pd). The emitter electrode 4 includes molybdenum, copper molybdenum, copper tungsten, or Invar as a main material, or is essentially composed of molybdenum, copper molybdenum, copper tungsten, or Invar.

[0023] As described above with reference to FIG. 1, the semiconductor device 1 may be included in a semiconductor module 110, and multiple semiconductor modules 110 may be stacked in the converter 100. In such applications, the semiconductor device 1 is subjected to a large load. In order to withstand this load, molybdenum, copper molybdenum, copper tungsten, or Invar is used. Molybdenum, copper molybdenum, copper tungsten, and Invar have high hardness.

[0024] When molybdenum is used, the surface of the emitter electrode 4 may be coated with one or more of nickel, gold (Au), palladium (Pd), and ruthenium (Ru).

[0025] Copper molybdenum is an alloy of copper and molybdenum. Copper tungsten is an alloy of copper and tungsten. Copper molybdenum and copper tungsten have higher heat dissipation properties than molybdenum and are less susceptible to thermal expansion than molybdenum.

[0026] Invar has a lower thermal expansion than molybdenum. When Invar is used, the emitter electrode 4 contains iron and cobalt, or iron and nickel.

[0027] The collector electrode 5 has a size that fits inside the edge of the semiconductor element 3 along the XY plane. The collector electrode 5 has a quadrilateral shape, for example, a rectangular shape, along the XY plane. The emitter electrode 4 contacts the collector electrode pad 32 of the semiconductor element 3. The collector electrode 5 is substantially made of the same material as the material that can be used as the emitter electrode 4.

[0028] The gate electrode pad 6 is a conductive member such as a metal. The gate electrode pad 6 is located in a notch of the emitter electrode 4. The gate electrode pad 6 has a quadrilateral shape along the XY plane, for example, a rectangular shape. The gate electrode pad 6 is spaced from the emitter electrode 4.

[0029] The cover 7 is an insulating member. The cover 7 has an annular shape along the XY plane and a quadrilateral outline, for example, a rectangular outline. The cover 7 is located around the semiconductor element 3 and extends continuously along the edge of the semiconductor element 3. The cover 7 is substantially made of insulating resin. Examples of the resin include PTFE (polytetrafluoroethylene).

[0030] Fig. 5 shows an example of a cross-sectional structure of the semiconductor device of the first embodiment. Fig. 5 shows the structure taken along line VV in Fig. 3 and Fig. 4, and shows the cross-sectional structure taken along the XZ plane. The semiconductor device 1 has the structure shown in Fig. 5 in any XZ plane and any YZ plane not including the gate electrode pad 6, for example.

[0031] As shown in Fig. 5, the semiconductor device 1 further includes conductors 11 and 12, and insulators 14 and 15. Fig. 5 also shows an emitter electrode pad 31 and a collector electrode pad 32 of the semiconductor element 3. The dimensions and positional relationships of some of the components shown in Fig. 5 will be described later with reference to Fig. 6.

[0032] The emitter electrode pad 31 extends along the XY plane and also extends along the XY plane of the semiconductor element 3 and extends over an area including one of the two opposing surfaces. Fig. 5 shows an example in which the emitter electrode pad 31 is located on the upper surface of the two opposing surfaces.

[0033] The collector electrode pad 32 faces the emitter electrode pad 31. The collector electrode pad 32 extends along the XY plane, and also extends along the XY plane of the semiconductor element 3 and extends over an area including the other of the two opposing surfaces. Fig. 5 shows an example in which the collector electrode pad 32 is located on the lower of the two opposing surfaces.

[0034] The emitter electrode 4 has a rectangular parallelepiped shape with its corners cut off to form a rectangular parallelepiped shape. The emitter electrode 4 faces the surface of the semiconductor element 3 on which the emitter electrode pad 31 is located, via the conductor 11. The emitter electrode 4 has a length L1 in the X direction.

[0035] The collector electrode 5 has a rectangular parallelepiped shape and faces the surface of the semiconductor element 3 on which the collector electrode pad 32 is located, via the conductor 12. The collector electrode 5 has a length L2 in the X direction. The length L2 is longer than the length L1.

[0036] The conductor 11 extends along the XY plane. The conductor 11 is located between the emitter electrode pad 31 and the emitter electrode 4, and contacts the upper surface of the emitter electrode pad 31 and the lower surface of the emitter electrode 4. The edge of the conductor 11 is located closer to the center line CL of the semiconductor device 1 than the edge of the emitter electrode 4.

[0037] Examples of the conductor 11 include metals, such as a sintered body of a metal. The sintered body is formed by heating and sintering a sheet or paste containing the material of the conductor 11. The conductor 11 is substantially made of a material that is easily bonded to the emitter electrode 4 based on the material of the emitter electrode 4. The conductor 11 is substantially made of a metal, and includes one or more of gold, silver (Ag), copper, lead (Pb), tin (Sn), and nickel. The conductor 11 includes gold, silver, copper, or solder as a main material, or is substantially made of gold, silver, copper, or solder.

[0038] Gold is difficult to oxidize and therefore easy to bond with many metals, and has higher electrical conductivity and heat dissipation than solder. Silver can be handled using common techniques, is relatively easy to obtain, and has higher electrical conductivity and heat dissipation than solder. Copper has high heat dissipation properties, is easily obtained, and has higher electrical conductivity and heat dissipation than solder. Solder is easily obtainable and can be handled using common techniques.

[0039] The conductor 12 extends along the XY plane. The conductor 12 is located between the collector electrode pad 32 and the collector electrode 5, and contacts the upper surface of the collector electrode 5 and the lower surface of the collector electrode pad 32. The edge of the conductor 12 is located closer to the center line CL of the semiconductor device 1 than the edge of the collector electrode 5. The conductor 12 is formed by heating and sintering a sheet or paste containing the material of the conductor 12. Examples of the conductor 12 include metals, for example, sintered bodies of metals. The conductor 12 is substantially made of a metal, and is substantially made of the same material as the material that can be used as the conductor 11.

[0040] The insulator 14 surrounds the conductor 11 along the XY plane, is located between the emitter electrode 4 and the upper surface of the semiconductor element 3, and is in contact with the lower surface of the emitter electrode 4 and the upper surface of the semiconductor element 3. The insulator 14 is also partially located between the upper surface of the semiconductor element 3 and the cover 7, and covers the upper surface of the semiconductor element 3 except for the region directly below the emitter electrode 4 and the region above the gate electrode pad 6. The insulator 14 is substantially composed of a heat-resistant organic material. The insulator 14 includes, for example, a component contained in a solvent of a paste or sheet containing elements of the conductor 11, or is substantially composed of such a component. An example of the component includes propylene carbonate.

[0041] The insulator 15 surrounds the conductor 12 along the XY plane, is located between the collector electrode 5 and the lower surface of the semiconductor element 3, and is in contact with the upper surface of the collector electrode 5 and the lower surface of the semiconductor element 3. The insulator 15 is substantially made of the same material as the material that can be used as the insulator 14.

[0042] The cover 7 covers the upper surface of the semiconductor element 3 except for the region directly below the emitter electrode 4 and the region above the gate electrode pad 6. The cover 7 also covers the lower surface of the semiconductor element 3 except for the region not covered by the insulator 15 or the collector electrode 5. The cover 7 also covers the entire side surface of the semiconductor element 3.

[0043] Fig. 6 shows an example of a cross-sectional structure of the semiconductor device of the first embodiment. Fig. 6 shows a structure taken along line VI-VI in Fig. 3 and Fig. 4, and shows a cross-sectional structure taken along the XZ plane. The semiconductor device 1 has the structure shown in Fig. 6 in any XZ plane and any YZ plane including the gate electrode pad 6, for example.

[0044] 6 and as described above with reference to Fig. 4, the gate electrode pad 6 is located in the notched portion of the emitter electrode 4. The gate electrode pad 6 is located in a region including the upper surface of the semiconductor element 3. The gate electrode pad 6 is not covered by the cover 7 and is exposed.

[0045] FIG. 7 shows an example of the cross-sectional structure of the semiconductor device of the first embodiment, and shows an enlarged portion of the side surface of the semiconductor device 1. As shown in FIG. 7, the edge of the collector electrode 5 and the side surface of the semiconductor element 3 have a distance D1. The edge of the emitter electrode 4 and the side surface of the semiconductor element 3 have a distance D2. The distance D2 is greater than the distance D1. This is for the following reason. That is, while the semiconductor element 3 is operating (while a voltage is applied to the emitter electrode 4 and the collector electrode 5), the potential of the collector electrode 5 is transmitted from the corner of the collector electrode 5 to the side surface of the semiconductor element 3, and the area along the side surface of the semiconductor element 3 and in the vicinity has the same potential as the potential of the collector electrode 5. Therefore, point A near the corner formed by the upper surface and the side surface of the semiconductor element 3 has the same potential as the collector electrode 5. Therefore, if the emitter electrode 4 is close to point A, a discharge may occur between point A and the emitter electrode 4. To avoid this, the emitter electrode 4 is located at a position away from point A, and therefore the distance D2 is greater than the distance D1.

[0046] The cover 7 includes a first portion 71 , a second portion 72 , a third portion 73 , a fourth portion 74 , and a fifth portion 75 .

[0047] The first portion 71 has a quadrilateral shape. The first portion 71 occupies an area including the entire side surface of the cover 7. The first portion 71 covers the entire side surface of the semiconductor element 3. The first portion 71 extends from the upper end to the lower end of the cover 7.

[0048] The second portion 72 has a quadrilateral shape. The second portion 72 occupies a region of the cover 7 between the first portion 71 and the collector electrode 5. The second portion 72 is located in a region including a part of the lower end of the cover 7. The second portion 72 contacts the side of the collector electrode 5 at its left side (the side closer to the center line CL of the semiconductor device 1). The upper edge of the second portion 72 is aligned with the upper surface of the collector electrode 5. The second portion 72 connects to the left edge of the first portion 71 (the side closer to the center line CL of the semiconductor device 1) at its right side (the side farther from the center line CL of the semiconductor device 1). The length of the second portion 72 in the X direction, i.e., the distance D1, is based on a dimension determined so that the second portion 72 covers a maximum of 5% of the lower surface of the semiconductor element 3.

[0049] The third portion 73 has a quadrilateral shape. The third portion 73 occupies a region of the cover 7 between the first portion 71 and the emitter electrode 4. The third portion 73 is located in a region including a part of the upper end of the cover 7. The third portion 73 contacts the side of the emitter electrode 4 at its left side (the side closer to the center line CL of the semiconductor device 1). The lower edge of the third portion 73 is located in the -Z direction from the lower surface of the emitter electrode 4. The third portion 73 is connected to the left edge of the first portion 71 (the side closer to the center line CL of the semiconductor device 1) at its right side (the side farther from the center line CL of the semiconductor device 1). The length of the third portion 73 in the X direction, i.e., the distance D2, is based on a dimension determined so that the third portion 73 covers a maximum of 20% of the upper surface of the semiconductor element 3.

[0050] The fourth portion 74 occupies the region of the cover 7 between the second portion 72 and the semiconductor element 3, and the region between the collector electrode 5 and the semiconductor element 3. The fourth portion 74 has a quadrilateral shape. The lower edge of the fourth portion 74 is connected to the upper edge of the second portion 72. The right edge of the fourth portion 74 (the side farther from the center line CL of the semiconductor device 1) is connected to the left edge of the first portion 71 (the side closer to the center line CL of the semiconductor device 1).

[0051] The fifth portion 75 occupies a region of the cover 7 between the third portion 73 and the semiconductor element 3. The fifth portion 75 has a quadrilateral shape. An upper edge of the fifth portion 75 is connected to a lower edge of the third portion 73. A right edge of the fifth portion 75 (the side farther from the center line CL of the semiconductor device 1) is connected to a left edge of the first portion 71 (the side closer to the center line CL of the semiconductor device 1).

[0052] The cover 7 covers the upper surface of the semiconductor element 3 except for the portion not covered by the emitter electrode 4 and the portion above the gate electrode pad 6. The cover 7 covers the lower surface of the semiconductor element 3 except for the portion not covered by the collector electrode 5.

[0053] The cover 7 sandwiches the upper and lower surfaces of the semiconductor element 3 between a first portion 71, a second portion 72, and a third portion 73. Due to such a shape of the cover 7, the cover 7 is fixed to the semiconductor element 3 without using an adhesive.

[0054] 1.2. Manufacturing method 8 and 9 show a part of the manufacturing process of the semiconductor device of the first embodiment. Fig. 9 shows the state before the collector electrode 5, the bonding material 21, the semiconductor element 3, the bonding material 22, the emitter electrode 4, the resin 7A, the jig 25, and the cushioning material 26 are stacked.

[0055] 8 and 9, the collector electrode 5, bonding material 21, semiconductor element 3, bonding material 22, emitter electrode 4, and buffer material 26 are stacked in this order in the +Z direction within the opening of the mask 27. The cross section of the mask 27 has a rectangular shape with the inner corners cut out into a rectangular shape. The bottom end of the cutout is approximately aligned with the top surface of the semiconductor element 3.

[0056] The bonding material 21 contains the conductor 12 and also contains the insulator 15 as a solvent, and has the shape of a sheet or paste. The bonding material 22 contains the conductor 11 and also contains the insulator 14 as a solvent, and has the shape of a sheet or paste.

[0057] Resin 7A is placed on the upper surface of the semiconductor element 3. Resin 7A is a material that will become cover 7 by sintering. Resin 7A has an annular shape and has an opening that is larger than the shape of emitter electrode 4 along the XY plane. Resin 7A is placed on the upper surface of the semiconductor element 3 so as to enclose emitter electrode 4 within its opening.

[0058] Jig 25 is placed on the upper surface of resin 7A. Jig 25 fixes the position of resin 7A. Jig 25 has an annular shape and has an opening that is larger than the shape of emitter electrode 4 along the XY plane. Jig 25 is placed on the upper surface of resin 7A so as to contain emitter electrode 4 within its opening.

[0059] A buffer material 26 is disposed on the upper surface of the emitter electrode 4. The buffer material 26 is made of, for example, substantially the same material as the material of the cover 7.

[0060] With the collector electrode 5, bonding material 21, semiconductor element 3, bonding material 22, emitter electrode 4, resin 7A, jig 25, and cushioning material 26 arranged as described above within the opening of mask 27, the upper surface of cushioning material 26 receives pressure by punch 29. With pressure applied, the structure consisting of collector electrode 5, bonding material 21, semiconductor element 3, bonding material 22, emitter electrode 4, resin 7A, jig 25, and cushioning material 26 is heated.

[0061] The bonding material 21 is sintered by heating while being pressurized. As a result, the conductor 12 is formed, and the semiconductor element 3 and the collector electrode 5 are bonded to each other via the conductor 12. Furthermore, the solvent in the bonding material 21 is diffused, and an insulator 15 is formed.

[0062] The bonding material 22 is sintered by heating while being pressurized. As a result, the conductor 11 is formed, and the semiconductor element 3 and the emitter electrode 4 are bonded via the conductor 11. Furthermore, the solvent of the bonding material 22 diffuses to form an insulator 14. Since the area of ​​the XY plane of the emitter electrode 4 is smaller than the area of ​​the XY plane of the collector electrode 5, the emitter electrode 4 receives a larger pressure than the collector electrode 5. Therefore, the solvent of the bonding material 22 spreads over a wider area than the solvent of the bonding material 21.

[0063] The resin 7A is deformed and spreads by heating while being pressurized. As a result, the resin 7A moves through the region between the mask 27 and the semiconductor element 3, and further reaches the region between the semiconductor element 3 and the collector electrode 5. In this way, the cover 7 is formed from the resin 7A. Even if a portion of the surface of the semiconductor element 3 that is not in contact with the cover 7 is formed, the region between the surface of the semiconductor element 3 and the cover 7 at such a portion is filled with the solvent of the bonding material 21 or 22, i.e., the insulator 15 or 16. Therefore, the portion of the surface of the semiconductor element 3 that is not in contact with the cover 7 is covered with the insulator 14 or 15.

[0064] After pressure and heat are applied, cleaning and the cover 7 is hardened, and the semiconductor device 1 is completed.

[0065] After hardening, the semiconductor device 1 may be heated, which softens the cover 7 and more reliably fills the area between the cover 7 and the semiconductor element 3, the emitter electrode 4, or the collector electrode 5 that was there before the cover 7 softened.

[0066] According to the first embodiment, as described below, it is possible to provide a semiconductor device 1 having a high breakdown voltage.

[0067] During the same pressure and heat process described above with reference to Figure 8, the bonding material, and therefore its constituent conductors, may protrude from the emitter or collector electrodes in the plane along the XY plane, and such protruding conductors may cause discharge between the collector and emitter electrodes.

[0068] According to the first embodiment, the semiconductor device 1 includes an insulating cover 7 having a shape that covers the side surfaces of the semiconductor element 3 and sandwiches the upper and lower surfaces of the semiconductor element 3. This suppresses protrusion of the conductors 11 and 12, and therefore suppresses discharge between the collector electrode 5 and the emitter electrode 4 caused by the protrusion of the conductors 11 or 12. This allows the semiconductor device 1 to have a high breakdown voltage.

[0069] According to the first embodiment, the cover 7 covers a portion of the upper surface of the semiconductor element 3 that is not covered by the emitter electrode 4, and also covers a portion of the lower surface of the semiconductor element 3 that is not covered by the collector electrode 5. Thus, the cover 7 covers the area from the end of the collector electrode 5 to the end of the emitter electrode 4. This covering with the cover 7 improves the insulation of the region between the collector electrode 5 and the emitter electrode 4, and a semiconductor device 1 having high withstand voltage can be realized.

[0070] The semiconductor device 1 includes insulators 14 and 15, and the insulator 14 partially fills the gap between the cover 7 and the semiconductor element 3 and partially covers the upper surface of the semiconductor element 3. The insulators 14 and 15 are derived from a solvent, i.e., a liquid, and fill the gap between the cover 7 and the semiconductor element 3 with high precision. Thus, the region between the end of the collector electrode 5 and the end of the emitter electrode 4 is covered with the cover 7 and the insulators 14 and 15 with high precision. This contributes to realizing a semiconductor device 1 with high withstand voltage.

[0071] The semiconductor device 1 does not use an adhesive to fix the cover 7 and the semiconductor element 3. In order to improve the pressure resistance of the semiconductor element, an insulating chip frame that surrounds the semiconductor element may be attached. This attachment may be performed using an adhesive. However, the components of the adhesive, such as siloxane, may deteriorate the characteristics of the semiconductor element. Since the semiconductor device 1 does not use an adhesive to fix the cover 7 and the semiconductor element 3, deterioration of the characteristics of the semiconductor element 3 caused by the adhesive is suppressed.

[0072] 1.3. Variations As shown in Fig. 10, the cover 7 may cover the entire side surface of the semiconductor element 3, only the vicinity of the edge of the upper surface of the semiconductor element 3, and only the vicinity of the edge of the lower surface. Such a shape of the cover 7 may be produced when the pressure and / or temperature in the pressurizing and compressing step described above with reference to Fig. 8 is lower than the pressure and / or temperature used in the step of Fig. 8. Even with the structure shown in Fig. 10, a high withstand voltage can be achieved because the side surface of the semiconductor element 3, which contributes greatly to the generation of discharge between the collector electrode 5 and the emitter electrode 4, is covered with the cover 7.

[0073] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented 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 in the scope of the invention and its equivalents described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0074] 1...Semiconductor device, 3...Semiconductor element, 4...Emitter electrode, 5...Collector electrode, 6...gate electrode pad, 7…Cover, 11...conductor, 12...Conductor, 14...insulator, 15...insulator, 21...bonding material, 22…bonding material, 25…jig, 26...Cushioning material, 27…Mask, 29...Punch, 31...emitter electrode pad, 32...Collector electrode pad, 100…Conversion device, 101...bottom, 102...side, 103…upper part, 105...Support, 106...cooling fin, 107...Support, 108...Spring, 110...semiconductor module, 131...Conductor, 132...terminal board, 135...external electrode, 136...External electrode

Claims

1. Extending along the first surface, a first surface, a second surface opposite to the first surface, and a third surface extending between an end of the first surface and an end of the second surface; a first electrode pad provided in a region including the first surface, and a second electrode pad provided in a region including the second surface; A semiconductor element; a first conductor in contact with the first electrode pad; a first electrode in contact with the first conductor; a second conductor in contact with the second electrode pad; a second electrode in contact with the second conductor; an insulating cover including a first portion, a second portion, and a third portion, the first portion covering the third surface, the second portion being connected to the first portion and facing the first surface, the third portion being connected to the first portion and facing the second surface, and sandwiching the semiconductor element together with the second portion; Semiconductor device.

2. the cover is continuous across an area facing the first surface, an area facing the second surface, and an area facing the third surface; The semiconductor device according to claim 1 .

3. The cover continuously surrounds the periphery of the semiconductor element along the first surface. The semiconductor device according to claim 1 .

4. a first insulator on the first surface; a second insulator on the second surface; and Further equipped with the second portion of the cover includes a portion that does not contact the first surface, the first insulator is located between the first surface and a portion of the second portion of the cover that does not contact the first surface, the third portion of the cover includes a portion that does not contact the second surface, the second insulator is positioned between the second surface and a portion of the second portion of the cover that does not contact the second surface. The semiconductor device according to claim 1 .

5. the second portion of the cover contacts the first electrode; The third portion of the cover contacts the second electrode. The semiconductor device according to claim 1 .

6. one or both of the first electrode and the second electrode comprises one or more of molybdenum, ruthenium, tungsten, iron, copper, cobalt, nickel, and palladium; The semiconductor device according to claim 1 .

7. one or both of the first conductor and the second conductor include one or more of gold, silver, copper, lead, tin, and nickel; The semiconductor device according to claim 1 .

Images