Semiconductor device and method for manufacturing the same

Abstract

The present invention relates to a semiconductor device and a method for manufacturing the same. The purpose is to provide a technology capable of suppressing the generation of an unfilled portion. The semiconductor device comprises a base plate, a housing, and a semiconductor element. The semiconductor element is arranged in a space between the base plate and the housing. The semiconductor device comprises a lead electrode. The lead electrode is connected to the upper surface of the semiconductor element in the space. The semiconductor device comprises a protrusion. The protrusion is arranged on the upper surface of the lead electrode in the space. The semiconductor device comprises a packaging resin. The packaging resin packages the semiconductor element and the lead electrode in the space.

Description

Technical Field

[0001] The present invention relates to a semiconductor device and a method for manufacturing the same. Background Art

[0002] A semiconductor device has been proposed that includes a substrate, a semiconductor element disposed on the substrate, lead electrodes connected to the upper surface of the semiconductor element, and a sealing resin sealing these in a space between a base plate and a casing (eg, Patent Document 1).

[0003] Patent Document 1: International Publication No. 2019 / 194272

[0004] Such a semiconductor device is manufactured by placing a substrate, a semiconductor element, and a lead electrode in the space and then injecting a fluid resin that becomes a sealing resin before curing into the space. However, there is a problem that, since the gap between the lead electrode and the base plate is narrow, an unfilled portion where the fluid resin is not filled is generated in a part of the gap, and the electrical insulation and reliability of the semiconductor device are reduced due to the unfilled portion. Summary of the invention

[0005] Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a technology capable of suppressing the occurrence of an unfilled portion.

[0006] The semiconductor device involved in the present invention comprises: a base plate; a shell, which surrounds the space above the base plate; a semiconductor element, which is arranged in the space; a lead electrode, which is connected to the upper surface of the semiconductor element in the space; a protrusion, which is arranged on the upper surface of the lead electrode in the space; and a packaging resin, which packages the semiconductor element and the lead electrode in the space.

[0007] Effects of the Invention

[0008] According to the present invention, since the protrusion is arranged on the upper surface of the lead electrode, the generation of the unfilled portion can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a cross-sectional view showing the structure of the semiconductor device according to the first embodiment.

[0010] Figure 2 This is a cross-sectional view for explaining the method for manufacturing the semiconductor device according to the first embodiment.

[0011] Figure 3 It is a cross-sectional view for explaining a method for manufacturing a related semiconductor device.

[0012] Figure 4It is a cross-sectional view showing the structure of a semiconductor device according to the second embodiment.

[0013] Figure 5 It is a cross-sectional view showing the structure of a semiconductor device according to the third embodiment. DETAILED DESCRIPTION

[0014] Below, while referring to the attached Figure 1 The embodiments are described in detail below. The features described in the following embodiments are only examples, and not all features are required. In addition, in the description shown below, the same structural elements are marked with the same or similar reference numerals in multiple embodiments, and mainly different structural elements are described. In addition, in the description recorded below, specific positions and directions such as "up" or "down" are not necessarily consistent with the directions in actual implementation.

[0015] <Implementation Method 1>

[0016] Figure 1 It is a cross-sectional view showing the structure of the semiconductor device according to the first embodiment. Figure 1 The semiconductor device includes a base plate 1 a , a housing 1 e , a semiconductor element 2 , bonding materials 2 a and 2 b , lead electrodes 3 , a protruding portion 4 , and a sealing resin 5 .

[0017] The housing 1e surrounds the space above the base plate 1a. In the following description, the space formed by the base plate 1a and the housing 1e is referred to as a "housing space."

[0018] The base plate 1a includes a heat sink 1b made of a metal such as aluminum alloy and copper, an insulating substrate 1c made of a ceramic such as aluminum nitride and silicon nitride, or a resin, and a metal pattern 1d made of a metal such as aluminum alloy and copper. The heat sink 1b functions as a heat sink.

[0019] The housing 1e is made of a resin such as PPS (Poly Phenylene Sulfide), etc. The housing 1e is bonded to the peripheral edge of the base plate 1a by, for example, a silicone resin.

[0020] The semiconductor element 2 is arranged in the housing space. The semiconductor element 2 may be, for example, a semiconductor switching element such as an IGBT (Insulated Gate Bipolar Transistor), a reverse conducting IGBT, and a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), or a diode such as a PND (PN junction Diode) and an SBD (Schottky Barrier Diode). The material of the semiconductor element 2 may be, for example, silicon (Si), or a wide bandgap semiconductor such as silicon carbide (SiC), gallium nitride (GaN), and diamond that has a larger bandgap than silicon. When the semiconductor element 2 is composed of a wide bandgap semiconductor, stable operation at high temperature and high voltage and high switching speed can be achieved.

[0021] exist Figure 1 In the example, two semiconductor elements 2 are each bonded to the metal pattern 1d via a bonding material 2a. In addition, the number of semiconductor elements 2 is not limited to two, and can be changed according to the application. The material of the bonding material 2a is determined in consideration of the operating temperature of the semiconductor device, but is usually solder.

[0022] The lead electrode 3 is made of metal, for example, and is connected to the upper surface of the semiconductor element 2 in the housing space. In this way, since the semiconductor element 2 and the external electrode are connected by the lead electrode 3 instead of by metal wire bonding, it is used as the path of the main current, so that high current density and high reliability can be achieved.

[0023] In the first embodiment, the lead electrode 3 includes a first lead electrode 3a and a second lead electrode 3b that are separated from each other. Figure 1 In the example, the first lead electrode 3a is bonded to the upper surface of one semiconductor element 2 via the bonding material 2b, and the second lead electrode 3b is bonded to the upper surface of another semiconductor element 2 via the bonding material 2b. The material of the bonding material 2b is determined in consideration of the operating temperature of the semiconductor device, but is usually solder.

[0024] In the following description, when the first lead electrode 3a and the second lead electrode 3b are not distinguished from each other, they are each referred to as the lead electrode 3. The number of the lead electrodes 3 is not limited to two, and can be changed according to the application.

[0025] The lead electrode 3 has an end 3c and an end 3d. The end 3c on the same side as the housing 1e is directly fixed to the housing 1e. The end 3d on the opposite side of the side wall of the housing 1e is indirectly fixed to the housing 1e. Figure 1 In the example, the area of ​​the upper surface of the lead electrode 3 is larger than the area of ​​the side surface of the lead electrode 3 .

[0026] The protrusion 4 is arranged on the upper surface of the lead electrode 3 in the housing space, and protrudes upward from the upper surface of the lead electrode 3. In the first embodiment, the protrusion 4 includes: a first protrusion 4a arranged on the upper surface of the first lead electrode 3a on the second lead electrode 3b side; and a second protrusion 4b arranged on the upper surface of the second lead electrode 3b on the first lead electrode 3a side.

[0027] In the following, when the first protrusion 4a and the second protrusion 4b are not distinguished, they are each described as a protrusion 4. In addition, the number of protrusions 4 is not limited to two, that is, the number of the first protrusion 4a and the second protrusion 4b is not limited to one, and can be changed according to the purpose.

[0028] The protrusion 4 includes a resin solidified material 4c and an adhesive material 4d for bonding the resin solidified material 4c to the lead electrode 3. The shape of the resin solidified material 4c can be any shape that can control the flow of the fluid resin described later, and can be a rectangular shape or an arc shape. The height of the resin solidified material 4c can also be less than or equal to about 10 mm, for example.

[0029] The sealing resin 5 is made of epoxy resin, for example, and seals the semiconductor element 2 and the lead electrodes 3 in the housing space. The sealing resin 5 protects the insulating substrate 1c, the semiconductor element 2 and the lead electrodes 3 from the external environment.

[0030] <Manufacturing method>

[0031] Next, Figure 1 The method for manufacturing a semiconductor device is divided into first to fifth steps and described in sequence.

[0032] <1st step>

[0033] The base plate 1a and the semiconductor element 2 are bonded together by the bonding material 2a. For example, a plate-like solder is placed on the metal pattern 1d as the bonding material 2a, and the plate-like solder is heated to its melting point to bond the semiconductor element 2 to the base plate 1a. Alternatively, for example, a paste solder is printed on the metal pattern 1d as the bonding material 2a, and the paste solder is heated to its melting point to bond the semiconductor element 2 to the base plate 1a.

[0034] <Step 2>

[0035] The housing space is formed by joining the housing 1e integrated with the lead electrode 3 to the base plate 1a. In parallel, a plate-shaped solder or solder paste is placed on the semiconductor element 2 as a joining material 2b, for example, and a silicone-based or epoxy-based adhesive material (not shown) is applied to the joint surface between the lower portion of the housing 1e and the heat sink 1b.

[0036] In this state, a load is applied from one of the base plate 1a and the housing 1e to the other, so that the lower portion of the housing 1e is brought into close contact with the heat sink 1b, and the lead electrode 3 and the bonding material 2b are brought into contact. Then, curing heating is performed to cure the adhesive material between the lower portion of the housing 1e and the heat sink 1b. In addition, a self-tapping screw (not shown) or the like may be used to fasten the housing 1e and the heat sink 1b instead of the adhesive material.

[0037] <Step 3>

[0038] The semiconductor element 2 and the lead electrode 3 are bonded together by the bonding material 2b. The heating for bonding by the bonding material 2b may be performed simultaneously with the curing of the adhesive material in the second step.

[0039] <Step 4>

[0040] By applying the adhesive material 4d to a part of the upper surface of the lead electrode 3 and arranging the resin cured material 4c on the adhesive material 4d, the protrusion 4 having a desired shape is provided on the upper surface of the lead electrode 3. The resin of the resin cured material 4c is, for example, a resin having a desired elastic modulus (e.g., about 9 to 13 GPa), desired heat resistance (e.g., about 200°C at maximum), and the same linear expansion coefficient as that of the encapsulating resin 5.

[0041] <Step 5>

[0042] like Figure 2 As shown, the nozzle 8 of the sealing resin injection machine is arranged above the end 3d side relative to the protrusion 4. For the structure assembled through the first step to the fourth step, the liquid fluid resin 5a that becomes the sealing resin 5 is ejected from the nozzle 8 and injected into the housing space. Thus, the semiconductor element 2 and the lead electrode 3 are sealed by the fluid resin 5a.

[0043] In addition, the encapsulating resin 5 and the fluid resin 5a use, for example, silicone gel or epoxy resin, but are not limited thereto, and any resin having desired elastic modulus (for example, about 0.1 to 10 MPa in the case of silicone gel and about 9 to 13 GPa in the case of epoxy resin), desired heat resistance (for example, about 200° C. at maximum), adhesiveness, desired linear expansion coefficient, etc. In addition, when the fluid resin 5a is injected into the housing space, the housing space may be decompressed.

[0044] The injected fluid resin 5a is cured in a curing furnace or the like to become the encapsulating resin 5. Figure 1 The semiconductor device is completed. The completed semiconductor device is inspected for required electrical characteristics, etc.

[0045] <Function of Implementation Method 1>

[0046] Before describing the operation of the first embodiment, a semiconductor device related to the semiconductor device according to the first embodiment (hereinafter referred to as a “related semiconductor device”) will be described. Figure 3 It is a cross-sectional view for explaining a method for manufacturing a related semiconductor device. In addition, in the related semiconductor device, the protrusion 4 is not provided.

[0047] like Figure 3 As shown in FIG. 1 , in the structure where the lead electrode 3 is connected to the upper surface of the semiconductor element 2, the gap (hereinafter referred to as "electrode lower gap") between the lead electrode 3 and the insulating substrate 1c or the semiconductor element 2 is narrow. Therefore, in the fifth step of injecting the fluid resin 5a, before the electrode lower gap is filled with the fluid resin 5a, the upper surface of the lead electrode 3 is mostly covered with the fluid resin 5a.

[0048] When the fluid resin 5a flowing on the upper surface of the lead electrode 3 and the fluid resin 5a flowing in the gap below the electrode merge, an unfilled portion 9 not filled with the fluid resin 5a is likely to be generated near the merging point in the gap below the electrode. Therefore, in the related semiconductor device, there is a problem that the electrical insulation and reliability are reduced due to the unfilled portion 9.

[0049] In contrast, according to the first embodiment, since the protrusion 4 is disposed on the upper surface of the lead electrode 3, the flow of the fluid resin 5a flowing on the upper surface of the lead electrode 3 is blocked by the protrusion 4. As a result, the flow of the fluid resin 5a in the gap below the electrode is relatively promoted, and the fluid resin 5a is filled in the order from the lower part to the upper part of the lead electrode 3. As a result, the generation of the unfilled portion 9 in the gap below the electrode can be suppressed, and the reduction in the electrical insulation and reliability of the semiconductor device caused by the unfilled portion 9 can be suppressed. This is also true when the viscosity of the fluid resin 5a is relatively large, such as about 100 Pa·s.

[0050] In addition, according to the first embodiment, the protrusion 4 includes a cured resin. According to such a structure, the protrusion 4 can be formed of a general material. In addition, since the shape, height, and size of the protrusion 4 can be easily changed, the shape, height, and size of the protrusion 4 can be easily adapted to the shape and size of the semiconductor device, the nozzle position, and the injection speed of the fluid resin 5a.

[0051] The projection 4 is not limited thereto, and may be, for example, a strip-shaped metal wire, a metal body, a part of the lead electrode 3, etc. When the projection 4 uses a part of the lead electrode 3, the number of components can be reduced.

[0052] In the first embodiment, the first protrusion 4a is disposed on the upper surface of the first lead electrode 3a on the second lead electrode 3b side, and the second protrusion 4b is disposed on the upper surface of the second lead electrode 3b on the first lead electrode 3a side. According to such a structure, the fluid resin 5a is guided between the first lead electrode 3a and the second lead electrode 3b by the first protrusion 4a and the second protrusion 4b, so that the flow of the fluid resin 5a in the gap below the electrodes can be promoted. As a result, the generation of the unfilled portion 9 in the gap below the electrodes can be suppressed.

[0053] <Implementation Method 2>

[0054] Figure 4 2 is a cross-sectional view showing the structure of a semiconductor device according to the second embodiment. The structure of the second embodiment is the same as that of the first embodiment except that the through hole 3e adjacent to the protrusion 4 in plan view is arranged in the lead electrode 3. The through hole 3e adjacent to the protrusion 4 in plan view means that the through hole 3e is in contact with the protrusion 4 in plan view, or the through hole 3e is located within a height range from the protrusion 4 to the protrusion 4 in plan view.

[0055] In addition, the shape of the through hole 3e is not limited thereto, and may be, for example, circular, rectangular, or other polygonal shapes. The number of through holes 3e arranged relative to one protrusion 4 may be one or more. Figure 4 As in the example of FIG. 1 , the through hole 3e is arranged between the end 3d of the lead electrode 3 and the portion provided with the protrusion 4, that is, arranged near the protrusion 4 on the upstream side with respect to the flow direction of the fluid resin 5a.

[0056] <Effects of Implementation Method 2>

[0057] In the second embodiment, similarly to the first embodiment, since the protrusions 4 are arranged on the upper surface of the lead electrode 3, the flow of the fluid resin 5a on the upper surface of the lead electrode 3 can be blocked by the protrusions 4, and the flow of the fluid resin 5a in the gap below the electrode can be promoted. As a result, the generation of the unfilled portion 9 in the gap below the electrode can be further suppressed.

[0058] In addition, according to the second embodiment, the through hole 3e adjacent to the protrusion 4 is arranged in the lead electrode 3 in a plan view. According to such a structure, when the fluid resin 5a is injected, the flow of the fluid resin 5a flowing on the upper surface of the lead electrode 3 is blocked by the through hole 3e. In addition, the fluid resin 5a flowing on the upper surface of the lead electrode 3 is guided to the electrode lower gap by the through hole 3e, so that the flow of the fluid resin 5a in the electrode lower gap can be further promoted compared with the first embodiment. As a result, the generation of the unfilled portion 9 in the electrode lower gap can be further suppressed.

[0059] In addition, if Figure 4 As shown, according to the structure in which the through hole 3e is arranged between the end 3d of the lead electrode 3 and the portion provided with the protrusion 4, the fluid resin 5a is guided to the through hole 3e by the protrusion 4. Therefore, the flow of the fluid resin 5a in the gap below the electrode can be further promoted, and the generation of the unfilled portion 9 in the gap below the electrode can be further suppressed.

[0060] <Implementation Method 3>

[0061] Figure 5 2 is a cross-sectional view showing the structure of the semiconductor device according to the third embodiment. In the third embodiment, the protrusion 4 is a part of the lead electrode 3. In addition, the protrusion 4 is inclined upward toward the end 3d, and the opening of the through hole 3e is toward the nozzle 8. Figure 5 In the example of FIG. 1 , the cross-sectional shape of the protrusion 4 has an arc shape, but is not limited thereto. In addition, the protrusion 4 can be formed cheaply by stamping or the like. Figure 5 According to the third embodiment, the cured resin 4c and the adhesive material 4d described in the first embodiment are not required, so that the cost can be suppressed.

[0062] Except for the above point, the structure of the present embodiment 3 is the same as that of the embodiment 2.

[0063] <Effects of Implementation Method 3>

[0064] In the third embodiment, similarly to the first and second embodiments, since the protrusions 4 are arranged on the upper surface of the lead electrode 3, the flow of the fluid resin 5a on the upper surface of the lead electrode 3 can be blocked by the protrusions 4, and the flow of the fluid resin 5a in the gap below the electrode can be promoted. As a result, the generation of the unfilled portion 9 in the gap below the electrode can be further suppressed.

[0065] In addition, according to the third embodiment, the protrusion 4 is inclined upward toward the end 3d. According to such a structure, even if the preceding fluid resin 5a is pushed by the following fluid resin 5a on the upper surface of the lead electrode 3, it is possible to suppress the preceding fluid resin 5a from passing over the protrusion 4. In addition, the fluid resin 5a is efficiently guided to the through hole 3e by the protrusion 4, so that the flow of the fluid resin 5a in the gap below the electrode can be further promoted, and the generation of the unfilled portion 9 in the gap below the electrode can be further suppressed.

[0066] In addition, the inclined protrusion 4 as in the third embodiment may be applied to the first embodiment instead of the second embodiment.

[0067] In addition, the embodiments and modifications may be freely combined, and the embodiments and modifications may be appropriately modified or omitted.

[0068] Description of the label

[0069] 1a base plate, 1e housing, 2 semiconductor element, 3 lead electrode, 3a first lead electrode, 3b second lead electrode, 3d end portion, 3e through hole, 4 protrusion, 4a first protrusion, 4b second protrusion, 4c cured resin, 5 packaging resin, 5a fluid resin.

Claims

1. A semiconductor device comprising: Base plate; a housing that surrounds the space above the base plate; A semiconductor element disposed in the space; a lead electrode connected to the upper surface of the semiconductor element in the space; a protrusion disposed on an upper surface of the lead electrode in the space; as well as a sealing resin that seals the semiconductor element and the lead electrode in the space, In a plan view, a communication space for communicating the upper and lower parts of the lead electrode is provided closer to the center of the space than the protrusion.

2. The semiconductor device according to claim 1, wherein The protrusion includes a cured resin.

3. The semiconductor device according to claim 1, wherein As the communication space, a through hole adjacent to the protrusion in a plan view is arranged in the lead electrode.

4. The semiconductor device according to claim 2, wherein: As the communication space, a through hole adjacent to the protrusion in a plan view is arranged in the lead electrode.

5. The semiconductor device according to claim 3, wherein: The lead electrode has an end portion on the opposite side to the side wall of the housing. The through hole is disposed between the end portion of the lead electrode and a portion where the protrusion is provided.

6. The semiconductor device according to claim 4, wherein: The lead electrode has an end portion on the opposite side to the side wall of the housing. The through hole is disposed between the end portion of the lead electrode and a portion where the protrusion is provided.

7. The semiconductor device according to any one of claims 1 to 6, wherein: The lead electrode has an end portion on the opposite side to the side wall of the housing. The protrusion is inclined upward toward the end portion.

8. The semiconductor device according to any one of claims 1 to 6, wherein: The lead electrode includes a first lead electrode and a second lead electrode separated from each other by the communication space. The raised portion comprises: a first protrusion disposed on an upper surface of the first lead electrode on the second lead electrode side; and The second protrusion is arranged on the upper surface of the second lead electrode on the first lead electrode side.

9. The semiconductor device according to claim 7, wherein: The lead electrode includes a first lead electrode and a second lead electrode separated from each other by the communication space. The raised portion comprises: a first protrusion disposed on an upper surface of the first lead electrode on the second lead electrode side; and The second protrusion is arranged on the upper surface of the second lead electrode on the first lead electrode side.

10. A method for manufacturing a semiconductor device, which is the method for manufacturing a semiconductor device according to any one of claims 1 to 9, The lead electrode has an end portion on the opposite side to the side wall of the housing. A fluid resin serving as the sealing resin is injected into the space from above the end portion with respect to the protrusion.

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