Semiconductor module and method for manufacturing semiconductor module

Abstract

The invention provides a semiconductor module and a method for manufacturing the semiconductor module, which can improve transportability when a gel is applied to a sealing material. The semiconductor module is provided with: a laminated substrate (5) on which a semiconductor element (1) is mounted; a case (7) that houses a member to be sealed that includes the semiconductor element (1) and the laminated substrate (5); a sealing material which is filled in the housing (7) and seals the member to be sealed; and a mica sheet (20) provided on the upper surface of the sealing material, the sealing material including a gel (11) on the mica sheet (20) side, and the mica sheet (20) being provided on the gel (11).

Description

Technical Field

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

[0002] Conventionally, there is known a power module including: one or more power semiconductor chips; a case that accommodates the power semiconductor chip; and silicone gel that fills the case and seals the power semiconductor chip (see Patent Document 1 below).

[0003] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2014-216558 Summary of the invention

[0004] Technical issues In conventional semiconductor modules, when gel is used as a sealing material, there is a problem that the transportability is deteriorated because the gel maintains adhesiveness even after curing.

[0005] The present disclosure aims to solve the above-mentioned problems in the conventional technology and to provide a semiconductor module and a method for manufacturing the semiconductor module that can improve the transportability when applying a gel to a packaging material.

[0006] Technical Solution In order to solve the above-mentioned problems and achieve the purpose of the present disclosure, the semiconductor module of the present disclosure has the following characteristics. The semiconductor module comprises: a laminate substrate on which a semiconductor element is mounted; a housing that accommodates a sealed component, the sealed component including the semiconductor element and the laminate substrate; a sealing material that is filled in the housing and seals the sealed component; and a mica sheet that is disposed on the upper surface of the sealing material. The sealing material includes a gel on the mica sheet side, and the mica sheet is disposed on the gel.

[0007] According to the above disclosure, since the mica sheet has no adhesiveness and excellent flame retardancy and insulation, it can be transported by adsorbing the upper surface with an adsorption nozzle, which can improve the transportability. As a result, there is no need to re-make the transport equipment for semiconductor modules using gel as a sealing material, which can reduce the depreciation cost, etc.

[0008] Technical Effects According to the semiconductor module and the method for manufacturing the semiconductor module of the present disclosure, there is an effect of being able to improve the transportability when applying the gel to the sealing material. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0010] Figure 2 It is a plan view showing the structure of a semiconductor module according to the embodiment.

[0011] Figure 3 It is a cross-sectional view showing the conveyance of the semiconductor module according to the embodiment.

[0012] Figure 4 1 is a flowchart showing a method for manufacturing a semiconductor module according to an embodiment.

[0013] Figure 5 This is a cross-sectional view showing the conveyance of a conventional semiconductor module sealed with epoxy resin.

[0014] Figure 6 This is a cross-sectional view showing the transportation of a conventional gel-sealed semiconductor module.

[0015] Explanation of symbols 1.101 Semiconductor Chip 2.102 Insulation substrate 3.103 first conductive plate 5.105 laminated substrate 7.107 Shell 9 Metal Terminals 10, 110 metal wire 11.111 Gel 20 Mica sheets 21, 121 adsorption nozzle 25, 125 bonding layer 50 Semiconductor modules 108 Epoxy resin DETAILED DESCRIPTION

[0016] <Overview of Embodiments of the Present Disclosure> In order to solve the above-mentioned problems and achieve the purpose of the present disclosure, the semiconductor module of the present disclosure has the following features. The semiconductor module comprises: a laminate substrate on which a semiconductor element is mounted; a housing that accommodates a sealed component, the sealed component including the semiconductor element and the laminate substrate; a sealing material that is filled in the housing and seals the sealed component; and a mica sheet that is disposed on the upper surface of the sealing material. The sealing material contains a gel on the mica sheet side, and the mica sheet is disposed on the gel.

[0017] According to the above disclosure, mica sheets have no adhesiveness and excellent flame retardancy and insulation, so they can be transported by adsorbing the upper surface with an adsorption nozzle, which can improve the transportability. As a result, there is no need to re-make transport equipment for semiconductor modules using gel as a sealing material, which can reduce depreciation costs, etc.

[0018] In addition, in the semiconductor module of the present disclosure, in the above disclosure, the sealing material seals the sealed component with the gel.

[0019] In addition, the semiconductor module of the present disclosure is characterized in that, in the above disclosure, the sealing material on the semiconductor element side is a resin, and a gel is provided on the resin.

[0020] According to the above disclosure, it is possible to prevent the layer joining the semiconductor element and the multilayer substrate from moving due to stress.

[0021] In addition, the semiconductor module of the present disclosure is characterized in that, in the above disclosure, the mica sheet covers 10% or more of the area of ​​the upper surface of the gel.

[0022] In addition, the semiconductor module of the present disclosure is characterized in that, in the above disclosure, the mica sheet has a thickness of 0.2 mm or more and 0.5 mm or less.

[0023] According to the above disclosure, deformation of the gel can be suppressed, and the ability of the gel to follow the surface shape can be ensured.

[0024] In order to solve the above-mentioned problems and achieve the purpose of the present disclosure, the manufacturing method of the semiconductor module of the present disclosure has the following characteristics. The manufacturing method of the semiconductor module includes: a first step of bonding a semiconductor element to a stacked substrate; a second step of mounting the stacked substrate on a housing; a third step of applying a gel inside the housing; a fourth step of curing the gel; and a fifth step of mounting a mica sheet on the upper surface of the gel.

[0025] In addition, the manufacturing method of the semiconductor module of the present disclosure is characterized in that, in the above disclosure, after the second step and before the third step, it includes: a sixth step of injecting resin into the housing; and a seventh step of curing the resin.

[0026] <Foundation underlying the present disclosure> First, the problems of conventional semiconductor modules are described. Conventional semiconductor modules include semiconductor chips, laminated substrates, housings, heat sinks, and metal wires. A semiconductor chip is a power semiconductor chip composed of a MOSFET, an IGBT, or a diode, etc., and the semiconductor chip is bonded to a laminated substrate by a bonding layer such as solder. A substrate having a first conductive plate of copper or the like on the front of an insulating substrate such as a ceramic substrate and a second conductive plate of copper or the like on the back is called a laminated substrate. The laminated substrate is bonded to a heat sink using a bonding layer such as solder. In addition, in the case of a MOSFET, an active electrode pad is formed on the surface of the semiconductor chip as a power terminal electrode pad (current supply terminal). In addition, as a take-out terminal from the power terminal electrode pad, a conductive connection component such as a lead frame and a metal wire is configured. A housing is bonded to the semiconductor module, and a cover is installed for the metal terminal to penetrate and protrude to the outside. A sealing material for insulating and protecting the laminated substrate and the semiconductor chip on the substrate from the external environment is filled in the housing.

[0027] Figure 5 1 is a cross-sectional view showing the conveyance of a conventional epoxy resin-sealed semiconductor module. Figure 5 , a semiconductor module using epoxy resin 108 as a sealing material is shown, and a semiconductor chip 101, a stacked substrate 105 having an insulating substrate 102 and a first conductive plate 103, a housing 107, the epoxy resin 108, a metal wire 110, and a bonding layer 125 are illustrated.

[0028] When the semiconductor module is transported in the manufacturing process, the adsorption nozzle 121 is transported by adsorption to the surface of the epoxy resin 108. Since the epoxy resin 108 is solidified after curing, there is no problem in adsorption.

[0029] However, there is a problem as follows: when using epoxy resin 108, if a small-capacity module product forms a short circuit caused by cracks in the chip and / or circuit, the circuit will not be disconnected due to the pressure caused by the shrinkage of the epoxy resin during curing, and the large current drive will cause continuous overcurrent application, eventually leading to a fire.

[0030] For this reason, in order to cut off the conduction path at the time of initial fire, a method of applying the gel 111 to the sealing material instead of the epoxy resin 108 is proposed. Figure 6 When gel 111 is used as a sealing material, it remains adhesive even after solidification and cannot be separated after adsorption, which makes it difficult to transport the adhesive and deteriorates the transportability of the manufacturing equipment.

[0031] Hereinafter, preferred embodiments of the semiconductor module and the method for manufacturing the semiconductor module of the present disclosure will be described in detail with reference to the drawings. However, the present disclosure is not limited to the embodiments described below.

[0032] (Implementation Method) Hereinafter, a semiconductor module according to an embodiment that solves the above-mentioned problems will be described. Figure 1 It is a cross-sectional view showing the structure of a semiconductor module according to an embodiment. Figure 2 It is a plan view showing the structure of a semiconductor module according to the embodiment. Figure 1 yes Figure 2 A-A' cross-sectional view. In the semiconductor module 50, a first conductive plate 3 made of copper is arranged on the front side, which is one surface of the insulating substrate 2, and a second conductive plate (not shown) made of copper or the like is arranged on the back side, which is the other surface, thereby forming a stacked substrate 5. On the front side of the first conductive plate 3 of the stacked substrate 5, a plurality of semiconductor chips 1 are mounted via a bonding layer 25 made of solder and / or sintered material. The first conductive plate 3 is formed on the front side (first main surface) of the insulating substrate 2 in a predetermined circuit pattern. The second conductive plate on the back side of the stacked substrate 5 is bonded to the front side of a heat dissipation base (not shown) via a bonding layer (not shown) made of solder and / or sintered material or the like. The second conductive plate may also be a metal foil formed on the entire back side of the insulating substrate 2.

[0033] The metal terminal 9 for extracting the signal from the outside is bonded to the housing 7. Furthermore, on the front side of the semiconductor chip 1 (e.g., the source electrode pad), a conductive connection component such as a pin terminal and a lead frame is installed via a metal wire 10 (bonding wire) such as an aluminum wire and a bonding layer (not shown). In addition, the semiconductor chip 1 and the metal terminal 9 are electrically connected by the metal wire 10 such as an aluminum wire. It should be noted that a lead frame can also be used. In addition, the inside of the housing 7 is filled with a gel 11 as a sealing material.

[0034] In addition, the sealing material may be a mixture of the gel 11 and a sealing resin (not shown). In this case, the sealing resin such as epoxy resin is used to fill the mixture. Figure 1 The line T is closer to the semiconductor chip 1 side, and the gel 11 is used to fill the sealing resin. The line T is about half the height of the shell 7. It is preferable to seal the metal wire 10 with a sealing resin. This is because if only the gel 11 is used in the temperature range of -50°C to 150°C, there is a possibility that the bonding layer 25 moves due to stress. In an embodiment, in order to improve the transportability, a mica sheet 20 is attached to the upper surface of the gel 11. It should be noted that the structure of the semiconductor module 50 shown in the figure is an example, and the present disclosure is not limited to this structure.

[0035] Figure 32 is a cross-sectional view showing the conveyance of a semiconductor module according to an embodiment. The semiconductor module 50 disclosed in the present invention is used for a small-capacity module product. A small-capacity module product is, for example, a product having a weight of 300 g or less, and more specifically, a product having a weight of 50 g or more and 150 g or less. During the conveyance of the small-capacity module product in the manufacturing process, the adsorption nozzle 21 is adsorbed on the upper surface of the semiconductor module for conveyance. Figure 3 As shown, even on the upper surface of the adhesive gel 11, since the mica sheet 20 has no adhesiveness, it can be transported by adsorbing the upper surface by the adsorption nozzle 21, which can improve the transportability. As a result, there is no need to re-make the transport equipment for the semiconductor module using the gel as the sealing material, which can reduce the depreciation cost, etc.

[0036] (Semiconductor chip 1) The semiconductor chip 1 is a power chip such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), an IGBT (Insulated Gate Bipolar Transistor), or an SBD (Schottky Barrier Diode), and a device using Si, SiC, or GaN can be used as a semiconductor substrate. The number of semiconductor chips 1 mounted can be one or more.

[0037] (Laminated substrate 5) The laminated substrate 5 can be composed of an insulating substrate 2, a first conductive plate 3 formed into a predetermined shape on one main surface thereof, and a second conductive plate formed on the other main surface. As the insulating substrate 2, a material with excellent electrical insulation and thermal conductivity can be used. As the material of the insulating substrate 2, for example, Al2O3, AlN, SiN, etc. can be listed. In particular, for high-voltage applications, it is preferred to use a material that takes into account both electrical insulation and thermal conductivity. AlN and SiN can be used, but are not limited to these. As the first conductive plate 3 and the second conductive plate, Cu (copper) or Cu alloy with excellent processability can be used. It should be noted that the Cu alloy is an alloy containing more than 80% Cu. Sometimes, the conductive plate that is not in contact with the semiconductor chip 1 among the conductive plates composed of such Cu or Cu alloy is also called the back copper foil or the back conductive plate. As a method for arranging a conductive plate on the insulating substrate 2, a direct bonding method (Direct Copper Bonding method: direct bonding copper method) or a brazing method (Active Metal Brazing method: active metal brazing method) can be listed. Alternatively, a Ni (nickel) plating or the like may be performed on the surface of the conductive substrate to form a Ni or Ni alloy layer.

[0038] (Joint layer 25) The bonding layer 25 can be formed using lead-free solder. Although Sn-Sb, Sn-Cu, Sn-Ag, Sn-Sb-Ag, etc. can be used, it is not limited to these. In addition, the bonding layer 25 can also be formed using a connecting material including tiny metal particles such as a sintered body of nanosilver particles.

[0039] (Shell 7) The lower end of the shell 7 made of resin or the like is bonded to the periphery of the heat dissipation base. The shell 7 is formed in a roughly rectangular cylindrical shape and surrounds the periphery of the front surface of the heat dissipation base. The shell 7 is formed with a box-shaped recessed portion, and the box-shaped recessed portion uses the front surface of the heat dissipation base as the bottom surface, and uses the inner wall of the shell 7 orthogonal to the front surface of the heat dissipation base as the side wall. Inside the recessed portion, a semiconductor chip 1 and a laminated substrate 5 and a wiring component that are wired by a wiring component of a metal wire 10 are accommodated. In addition, a connection element made of a Cu alloy can also be used to wire the semiconductor chip 1 and the laminated substrate 5. The material of the shell 7 can also be a thermoplastic resin such as polyphenylene sulfide (PPS) and polybutylene terephthalate (PBT), or a thermosetting resin such as a phenolic resin.

[0040] (Gel 11) The gel 11 is a substance having high viscosity and which loses fluidity and becomes solid. The gel 11 is, for example, silicone gel.

[0041] (Mica sheet 20) The mica sheet 20 is the most suitable component for the cover of the semiconductor module 50 because of its excellent flame retardancy and insulation. The elastic modulus of the mica sheet 20 is about 74 GPa ± 10%. Compared with the elastic modulus of silicone rubber of 0.001 to 0.1 GPa, the mica sheet 20 has a moderate elastic modulus, so it is not easy to deform excessively and has excellent handling properties. Furthermore, since the elastic modulus is not too large, it can follow the surface shape of the gel 11 when pasting, and the adhesion is also good.

[0042] The shape of the mica sheet 20 is preferably the same as the shape of the upper surface of the semiconductor module 50, and the area of ​​the mica sheet 20 is preferably greater than the area of ​​the portion adsorbed by the adsorption nozzle 21. Since the portion adsorbed by the adsorption nozzle 21 is a circle or ellipse with a diameter or a long diameter of 30 mm or more and 50 mm or less, the shape of the mica sheet 20 is preferably a rectangle with a short diameter of 30 mm or more and 50 mm or less. In addition, the mica sheet 20 is preferably a size that covers more than 10% of the area of ​​the upper surface of the gel 11, for example. Furthermore, multiple mica sheets 20 may be pasted according to the shape of the adsorption nozzle 21 for transportation. In addition, in order to suppress the deformation of the gel 11 and ensure the followability of the surface shape of the gel 11, the thickness of the mica sheet 20 is preferably greater than 0.2 mm and less than 0.5 mm. In the embodiment, although the mica sheet 20 is used, other materials may also be used if they have flame retardancy, insulation, hardness, and can follow the surface shape of the gel 11.

[0043] (Method for Manufacturing Semiconductor Module According to Embodiment) Next, a method for manufacturing the semiconductor module according to the embodiment will be described. Figure 4 1 is a flowchart showing a method for manufacturing a semiconductor module according to an embodiment. First, the semiconductor chip 1 is bonded to the heat dissipation base and the laminate substrate 5 by the bonding layer 25 (step S1 : first process).

[0044] After that, the housing 7 is mounted on the heat dissipation base, and then the laminated substrate 5 is mounted on the housing 7 (step S2: second process). Next, the lead frame is joined and wire bonding is performed on the metal wire 10 (step S3).

[0045] Next, a sealing resin such as epoxy resin is injected into the housing 7 (step S4: sixth step). Next, the sealing resin is pre-cured at 100 to 120° C. for 10 to 120 minutes, and is fully cured at about 175 to 185° C. for 1 to 2 hours (step S5: seventh step). Steps S4 and S5 are performed in the case of a mixed structure of the gel 11 and the sealing resin, and are not necessary in the case of filling only with the gel 11 without using the sealing resin.

[0046] Next, the gel 11 is applied to the shell 7 (step S6: the third process). Next, the gel 11 is cured (step S7: the fourth process). Next, the mica sheet 20 is mounted on the upper surface of the gel 11 (step S8: the fifth process). When mounting, the mica sheet 20 can be placed on the upper surface of the gel 11 and pushed in. For the attachment of the mica sheet 20, the adhesiveness of the gel 11 itself can be used, or an adhesive can be used separately. In the case of utilizing the adhesiveness of the gel 11, the mica sheet 20 can be attached by simply placing it on the upper surface of the gel 11, and no adhesive process is required, which can reduce equipment costs and man-hours. In this way, it is possible to manufacture the mica sheet 20 as described above. Figure 1 as well as Figure 2 A semiconductor module 20 is shown.

[0047] As described above, according to the semiconductor module and the method for manufacturing the semiconductor module of the embodiment, since the mica sheet has no adhesiveness and excellent flame retardancy and insulation, it can be transported by adsorbing the upper surface with an adsorption nozzle, which can improve the transportability. As a result, there is no need to re-manufacture the transport equipment for the semiconductor module using gel as the sealing material, which can reduce the depreciation cost, etc.

[0048] As described above, the present invention can be variously modified within the scope of the gist of the present invention, and in the above-mentioned embodiments, various settings are made according to the specifications required, such as the size of each part, the impurity concentration, etc. In addition, in the above-mentioned embodiments, as a semiconductor, in addition to silicon, wide-bandgap semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) can also be applied.

[0049] Industrial Applicability As described above, the semiconductor module and the method for manufacturing the semiconductor module of the present invention are useful for power semiconductor modules used in power conversion devices such as inverters, power supply devices used in various industrial machines, and ignition devices for automobiles.

Claims

1. A semiconductor module, characterized in that: have: A laminate substrate having a semiconductor element mounted thereon; a housing that accommodates a sealed component, the sealed component including the semiconductor element and the laminated substrate; A sealing material filled in the housing and sealing the sealed component; as well as a mica sheet disposed on the upper surface of the sealing material, The sealing material includes a gel on the mica sheet side, and the mica sheet is disposed on the gel.

2. The semiconductor module according to claim 1, characterized in that The sealing material seals the sealed member using the gel.

3. The semiconductor module according to claim 1, characterized in that The sealing material is a resin on the semiconductor element side, and a gel is provided on the resin.

4. The semiconductor module according to claim 1, characterized in that The mica sheet covers more than 10% of the area of ​​the upper surface of the gel.

5. The semiconductor module according to claim 1, characterized in that The mica sheet has a thickness of 0.2 mm or more and 0.5 mm or less.

6. A method for manufacturing a semiconductor module, characterized in that: include: In a first step, a semiconductor element is bonded to a laminate substrate; A second step is to mount the laminated substrate on a housing; The third step is to apply gel inside the shell; The fourth step is to solidify the gel; as well as In the fifth step, a mica sheet is placed on the upper surface of the gel.

7. The method for manufacturing a semiconductor module according to claim 6, characterized in that: After the second step and before the third step, the method includes: A sixth step is to inject resin into the housing; and The seventh step is to cure the resin.

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