WO2018179573A1 - パワー半導体モジュール - Google Patents

パワー半導体モジュール Download PDF

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Publication number
WO2018179573A1
WO2018179573A1 PCT/JP2017/041164 JP2017041164W WO2018179573A1 WO 2018179573 A1 WO2018179573 A1 WO 2018179573A1 JP 2017041164 W JP2017041164 W JP 2017041164W WO 2018179573 A1 WO2018179573 A1 WO 2018179573A1
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Prior art keywords
base plate
metal base
semiconductor element
power semiconductor
substrate
Prior art date
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PCT/JP2017/041164
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English (en)
French (fr)
Inventor
柳浦　聡
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三菱電機株式会社
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Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to DE112017007351.0T priority Critical patent/DE112017007351B4/de
Priority to US16/483,970 priority patent/US10892203B2/en
Priority to JP2018513694A priority patent/JP6395173B1/ja
Priority to CN201780088342.5A priority patent/CN110447098B/zh
Publication of WO2018179573A1 publication Critical patent/WO2018179573A1/ja

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    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
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    • H01L29/72—Transistor-type devices, i.e. able to continuously respond to applied control signals
    • H01L29/739—Transistor-type devices, i.e. able to continuously respond to applied control signals controlled by field-effect, e.g. bipolar static induction transistors [BSIT]
    • H01L29/7393—Insulated gate bipolar mode transistors, i.e. IGBT; IGT; COMFET
    • H01L29/7395—Vertical transistors, e.g. vertical IGBT
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    • H01L2924/13—Discrete devices, e.g. 3 terminal devices
    • H01L2924/1304—Transistor
    • H01L2924/1305—Bipolar Junction Transistor [BJT]
    • H01L2924/13055—Insulated gate bipolar transistor [IGBT]

Definitions

  • the present invention relates to a power semiconductor module in which a semiconductor element disposed in a case is sealed with a potting sealant.
  • a transfer sealing type often found in small power semiconductor modules
  • a potting sealing type also referred to as a case type
  • a conventional potting-sealed power semiconductor module has a case composed of a metal base plate and a frame-like case wall surrounding the metal base plate, an electrode, and is fixed on the metal base plate and disposed in the case Ceramic substrate, a semiconductor element mounted on the ceramic substrate, a wire for electrically connecting the electrode of the ceramic substrate and the semiconductor element, and filling in the case to seal each component in the case
  • a silicone gel that is a potting sealant and a lid that closes the opening at the top of the case are provided.
  • a leakage current generated inside the element is suppressed by disposing an insulating low-charge material lower in charge than the sealant around the wire to suppress charge injection from the wire to the sealant.
  • production of this was suppressed (for example, refer patent document 1).
  • the potting sealant has two layers, and the semiconductive particles are dispersed in the lower layer (element, substrate side), so that the insulation resistance has non-linearity, and the electric field can be relaxed in a portion where the electric field is high (for example, see Patent Document 2).
  • the ionic gel to which the ionic liquid is added is applied to the intersection between the main surface of the insulating substrate and the side surface of the conductor plate disposed on the main surface of the insulating substrate, and then the entire gel is added with no ionic liquid added.
  • the electric field on the creeping surface of the insulating substrate is relaxed, and discharge at that portion can be suppressed (for example, see Patent Document 3).
  • the present invention has been made to solve such a problem, and can suppress generation of cracks in an insulating substrate and a decrease in withstand voltage of the module, suppress electric field concentration on the guard ring, It is an object of the present invention to provide an inexpensive power semiconductor module that can reduce an in-element leakage current generated inside and can maintain the electric field relaxation force of a potting sealant for a long period of time.
  • the power semiconductor module according to the present invention includes a metal base plate, an insulating substrate disposed on the metal base plate and having electrodes, a semiconductor element disposed on the insulating substrate, the insulating substrate, and the semiconductor A case disposed on the metal base plate so as to surround the element, and a potting sealant that fills a space surrounded by the metal base plate and the case and seals the insulating substrate and the semiconductor element
  • the potting sealant includes a silicone gel and a conductivity imparting agent that is added to the silicone gel and includes a silicon atom and an ionic group.
  • the potting sealant it is not necessary to make the potting sealant into two layers, so that it is inexpensive.
  • the concentration of the conductivity-imparting agent contained in the silicone gel is uniform, there is no decrease in the ion concentration in the silicone gel due to diffusion, and the electric field relaxation force of the potting sealant is maintained for a long time. Since the potting sealant is a gel, the generation of cracks in the insulating substrate can be suppressed. Since the potting agent is made by adding a conductivity-imparting agent to the gel, the interface insulation resistance between the potting sealant and the semiconductor element is lowered, the amount of accumulated charge at the interface is reduced, and the element leakage current inside the element Can be reduced. In addition, the conductivity of the potting sealant is not so great as to reduce the insulation of the module, but rather acts to alleviate the electric field concentration, and the reduction in the withstand voltage of the module itself is suppressed.
  • FIG. 1 is a sectional view showing a power semiconductor module according to an embodiment of the present invention
  • FIG. 2 is a top view showing a semiconductor element in the power semiconductor module according to an embodiment of the present invention.
  • a power semiconductor module 100 is disposed by being bonded to a metal base plate 5, a DBC (Direct Bond Copper) substrate 3 that is bonded and disposed on the metal base plate 5, and a DBC substrate 3.
  • a potting sealant 1 that fills a space formed by the metal base plate 5 and the case 7 and seals components such as the DBC substrate 3 and the semiconductor element 6 and the upper opening of the case 7 are closed.
  • a lid 8 8
  • the DBC substrate 3 is configured by directly joining circuit layers formed of copper or a copper alloy on both surfaces of the insulating substrate 3a.
  • the insulating substrate 3a is composed of a ceramic substrate or the like.
  • the circuit network disposed on the upper surface of the insulating substrate 3a is the upper electrode 3b, and the circuit network disposed on the lower surface of the insulating substrate 3a is the lower electrode 3c.
  • the semiconductor element 6 is a power semiconductor element such as an IGBT or a MOSFET.
  • Bonding between the metal base plate 5 and the DBC substrate 3 and bonding between the DBC substrate 3 and the semiconductor element 6 include bonding using solder, bonding using metal nanoparticles, bonding by metal diffusion, and bonding by ultrasonic waves. Used. Between the semiconductor elements 6, the semiconductor element 6 and the upper electrode 3 b of the DBC substrate 3 are electrically connected by wire bonding, that is, by wires 9.
  • an electric field relaxation pattern called a guard ring 11 is formed.
  • the guard ring 11 is composed of a plurality of conductive rings spaced apart from each other and formed around the outer peripheral edge of the surface of the semiconductor element 6.
  • the electrode 10 is formed in a region surrounded by the guard ring 11 on the surface of the semiconductor element 6.
  • the number of guard rings 11 is appropriately set depending on the type of semiconductor element 6.
  • a semiconductive SinSiN film sini-insulating silicon nitride film for electric field relaxation is formed between the conductive rings of the guard ring 11 on the surface of the semiconductor element 6 by CVD.
  • the potting sealant 1 is configured by adding a conductivity-imparting agent to the gel, and lowers the interface insulation resistance between the potting sealant 1 and the semiconductor element 6.
  • the gel has a high viscosity due to the dispersoid network, loses fluidity, and becomes a solid as a whole system.
  • the gel of the potting sealant 1 has a low stress acting on the wire 9 and preferably uses a low elastic modulus material from the viewpoint of ensuring long-term reliability of wire bonding.
  • a silicone gel is used. .
  • the silicone gel may be an addition type or a condensation type.
  • the silicone gel may be dimethylpolysiloxane or methylphenylpolysiloxane.
  • the conductivity imparting agent needs to be compatible with the silicone gel
  • a silicone-modified ionic liquid is preferable. That is, the conductivity-imparting agent includes silicon atoms and ionic groups.
  • the silicone-modified ionic liquid is compatible with the silicone gel before being cured, but has a property of collecting on the surface of the semiconductor element and the substrate when the silicone gel is cured. Therefore, since only the interfacial insulation resistance between the potting sealant 1 and the semiconductor element and the potting sealant 1 and the substrate can be lowered without excessively reducing the volume insulation resistance of the potting sealant 1, the silicone-modified ion The amount of the functional liquid added is small.
  • the potting sealant 1 is configured by adding a conductivity imparting agent to a silicone gel, the potting sealant 1 does not have a non-linear insulation resistance. Therefore, it is possible to suppress the occurrence of a decrease in withstand voltage of the module itself due to the dispersion of the nonconductive particles, which is a problem in Patent Document 2.
  • the potting sealant 1 is not so large as to reduce the insulation of the module, but rather acts to alleviate electric field concentration. Thereby, the withstand voltage fall of module itself can be suppressed.
  • the potting sealant 1 filled in the space formed by the metal base plate 5 and the case 7 is not covered with a gel containing no ionic liquid.
  • the concentration of the conductivity-imparting agent in the potting sealant 1 is uniform. Therefore, a decrease in the concentration of the conductivity imparting agent in the potting sealant 1 is suppressed, and the electric field relaxation force is maintained for a long period.
  • the conductivity-imparting agent that is not silicone-modified is not compatible with the silicone gel and is therefore separated.
  • Enstat PR-IL1 product name of Kaken Sangyo Co., Ltd.
  • an ionic liquid that is a conductivity imparting agent not modified with silicone was added to the silicone gel, it was not compatible with the silicone gel.
  • FIG. 3 is a cross-sectional view of a principal part for explaining the charge accumulation around the guard ring and the state of the depletion layer boundary line in the power semiconductor module of the comparative example
  • FIG. 4 is around the guard ring in the power semiconductor module according to one embodiment of the present invention. It is principal part sectional drawing explaining the electric charge accumulation and the state of a depletion layer boundary.
  • the element 6 is sealed with a silicone gel 20 as a potting sealant to which no conductivity imparting agent is added.
  • a semiconductor element 6 configured in the same manner is sealed with a potting sealant 1 obtained by adding a conductivity-imparting agent to silicone gel.
  • the silicone gel 20 is the same as the silicone gel constituting the potting sealant 1.
  • the deformation of the void layer boundary 19 causes non-uniformity of the electric field between the aluminum electrodes 12 constituting the guard ring 11, that is, electric field concentration. In the portion where the electric field is concentrated, there is a possibility of causing dielectric breakdown.
  • the electrical resistance increases at a low temperature because the temperature dependence of the electrical resistance of the SinSiN film is large. Therefore, in the power semiconductor module 200 of the comparative example, when the temperature becomes low and the SinSiN film has a high resistance, the charges emitted from the wires 9 and reaching the region of the guard ring 11 do not move, and the charge accumulation is promoted. As a result, in the low temperature region, the in-element leakage current generated in the element internal vacancy layer of the semiconductor element 6 is further increased.
  • the potting sealant 1 is in contact with the surface of the semiconductor element 6 and the guard ring 11 at the outer peripheral edge of the surface of the semiconductor element 6. Therefore, the conductivity imparting agent added to the silicone gel gathers on the surface of the semiconductor element 6, and the interfacial insulation resistance between the semiconductor element 6 and the potting sealant 1 is lowered. As a result, the electric charges emitted from the wire 9 and reaching the area of the guard ring 11 move quickly, and the accumulation of the electric field is alleviated. That is, as shown in FIG. 4, in the region between the aluminum electrodes 12 constituting the guard ring 11, the charge accumulated at the interface between the semiconductor element 6 and the potting sealant 1 is relaxed and reduced. Therefore, the depletion layer boundary 19 maintains a normal shape, and an increase in the element leakage current that occurs in the element depletion layer is suppressed.
  • FIG. 5 is a diagram showing a result of measuring element leakage current of an IGBT element potted with a silicone gel to which no conductivity-imparting agent is added
  • FIG. 6 is an IGBT element potted with a silicone gel to which a conductivity-imparting agent is added. It is a figure which shows the result of having measured the element leak current.
  • the element leakage current was measured with one chip at room temperature. The evaluation here is not performed by separately measuring only the leakage current in the element. That is, the element leakage current here includes the element leakage current.
  • the present applicant conducts electricity by interfacial insulation resistance (current value) between the potting sealant and the substrate in a configuration in which the comb-shaped electrode substrate having the comb-shaped counter electrode pattern formed on the surface of the ceramic substrate is sealed with the potting sealant.
  • current value interfacial insulation resistance
  • the present applicant has determined that the range of the optimum addition amount of the conductivity-imparting agent can be defined not by the addition amount but by the range of the interface insulation resistance between the potting sealant and the substrate after the addition of the conductivity-imparting agent. .
  • FIG. 7 is a top view showing a comb-shaped electrode substrate
  • FIG. 8 is a schematic diagram for explaining a method of measuring the interfacial insulation resistance of the comb-shaped electrode substrate
  • FIG. FIG. 8 is a schematic diagram for explaining a method of measuring the interfacial insulation resistance of the comb-shaped electrode substrate
  • the comb-shaped electrode substrate 21 as an evaluation substrate is subjected to nickel plating on one surface of a DBC substrate formed by bonding copper to one surface of an insulating substrate 22, patterned by etching, and comb-shaped opposing
  • the electrode pattern 23 is formed and manufactured. Therefore, the comb-shaped counter electrode pattern 23 has a two-layer structure of nickel and copper.
  • the insulating substrate 22 is a 45.2 mm ⁇ 34 mm ⁇ 0.635 mm silicon nitride substrate.
  • the comb-shaped counter electrode pattern 23 is a pattern in which combs of a pair of electrodes are alternately arranged 1 mm apart.
  • the interface insulation resistance was measured in a state where the comb-shaped electrode substrate 21 was housed in a case 24 and sealed with a potting sealant 25 as shown in FIG.
  • the electrode lines 27 and 28 drawn from the electrode lead portions 23 a of the comb-shaped counter electrode pattern 23 of the comb-shaped electrode substrate 21 are connected to the high resistance meter 26.
  • a DC voltage of 1 kV was applied to the electrode lines 27 and 28 to measure the interdigital electrode interface leakage current between the interdigital electrode substrate 21 and the potting sealant 25, and the result is shown in FIG. In FIG.
  • a potting sealant 25 is used which is prepared by adding 0.00005 wt% of X-40-2450 (product name of Shin-Etsu Chemical Co., Ltd.) to SE-1885 (product name of Toray Dow Corning Co., Ltd.). The case is shown by a solid line, and the case where only silicone gel is used as the potting sealant 25 is shown by a dotted line. SE-1885 is cured into a silicone gel.
  • X-40-2450 is an ionic group-containing silicone oligomer (silicone-modified ionic liquid) obtained by modifying an ionic liquid with silicone. The ionic group is bistrifluoromethanesulfonimide and functions as a conductivity-imparting agent. To do.
  • FIG. 10 is a top view showing a state in which a semiconductor element is mounted on the metal base plate of the evaluation module
  • FIG. 11 is a cross-sectional view showing the module assembly of the evaluation module
  • FIG. 12 is sealed with a potting sealant used in the evaluation module.
  • FIG. 13 is a figure which shows the evaluation result of an evaluation module.
  • the metal base plate 5 was a 190 mm ⁇ 140 mm ⁇ 3 mm copper plate.
  • a substrate in which a network made of copper was directly bonded to both surfaces of an insulating substrate 3a made of silicon nitride of 51 mm ⁇ 30 mm ⁇ 1 mm was used.
  • an IGBT 6a and an FWD (Free Wheeling Diode) 6b are used.
  • the gel for the potting sealant 1 SE-1885, which was cured to become a silicone gel, was used.
  • X-40-2450 was used as the conductivity-imparting agent.
  • each DBC substrate 3 was mounted on the metal base plate 5, and three IGBTs 6 a and FWDs 6 b were mounted on each DBC substrate 3.
  • the DBC substrates 3 were electrically connected by wire bonding.
  • the frame-like case 7 was attached to the metal base plate 5 so as to surround the DBC substrate 3, thereby producing a module assembly 110.
  • the amount of X-40-2450 added is 0.1 wt%, 0.05 wt%, 0.005 wt%, 0.001 wt%, 0.0005 wt%, 0.0001 wt%, 0.00005 wt%, 0.005 wt%
  • 0.1 wt%, 0.05 wt%, 0.005 wt%, 0.001 wt%, 0.0005 wt%, 0.0001 wt%, 0.00005 wt%, 0.005 wt% Nine types of evaluation modules were produced with a concentration of 00001 wt% and 0.000001 wt%.
  • the evaluation module was evaluated with two items of element leakage current at room temperature and partial discharge by alternating current, and the evaluation results are shown in FIG.
  • the element leakage current was evaluated by applying a DC voltage of 5200 V to the evaluation module and measuring the element leakage current at room temperature. Then, in consideration of the examination results of FIGS. 5 and 6, the case where the measured value of the element leakage current was less than 20 mA was determined to be acceptable.
  • the partial discharge was evaluated by increasing the voltage applied to the evaluation module at 5 kV steps at 30-second intervals and measuring the discharge charge. And the case where the voltage from which the measured value of the discharge charge is 10 pC or more is 11.5 kV or less was regarded as acceptable. Even when no discharge occurred, that is, when the voltage was 11.5 kV or less, the insulation test was rejected if the current value was 50 mA or more.
  • the comb-shaped electrode substrate 21 shown in FIG. 7 is sealed with nine types of potting sealants 1 with different amounts of X-40-2450 added, and the comb-shaped electrode on the comb-shaped electrode substrate 21 is measured by the measurement method shown in FIG.
  • the interface leakage current was measured, and the measurement result is shown in FIG.
  • FIG. 13 shows measured values of interdigital electrode interface leakage current 300 seconds after the voltage was applied to the interdigital electrode substrate 21.
  • the measured value of the interdigital electrode interface leakage current is the current value of the insulation resistance of the interface using the potting sealant 1.
  • the element leakage current is less than 20 mA, but when the addition amount is 0.000001 wt% or less, It was found that the element leakage current was 20 mA or more. This is because when the addition amount is 0.000001 wt% or less, the interfacial insulation resistance becomes too low, the electric charge that has been released from the wire 9 and reaches the region of the guard ring 11 is accumulated, and the element leakage current increases. It is inferred.
  • FIG. 13 shows that partial discharge and insulation failure occur when the added amount of the conductivity imparting agent X-40-2450 exceeds 0.005 wt%. This is presumably due to the fact that when the addition amount is more than 0.005 wt%, the interfacial insulation resistance becomes too high, and current leaks at the interface between the gel and the half-layer element, the creepage of the substrate, etc.
  • the addition amount is more than 0.005 wt%, the interfacial insulation resistance becomes too high, and current leaks at the interface between the gel and the half-layer element, the creepage of the substrate, etc.
  • the addition amount of the conductivity imparting agent X-40-2450 is 0.005 Wt% or less and 0.00001 wt% or more.
  • the interdigital electrode interface leakage current is 1.5 ⁇ 10 ⁇ 8 A, and when the added amount of X-40-2450 is 0.00001 Wt%.
  • the interdigital electrode interface leakage current was 4.2 ⁇ 10 ⁇ 10 A.
  • the addition amount of the conductivity imparting agent may be adjusted so that the interdigital electrode interface leakage current is 1.5 ⁇ 10 ⁇ 8 A or less and 4.2 ⁇ 10 ⁇ 10 A or more.
  • X-40-2450 was used as the conductivity-imparting agent, but the conductivity-imparting agent is not limited to X-40-2450, and an ionic liquid compatible with the silicone gel, that is, a silicone-modified ionic solution. If it is.
  • the silicone gel was used as the gel, the gel is not limited to the silicone gel, and may be a low elastic modulus gel.
  • the conductivity imparting agent may be an ionic liquid that is compatible with the gel, and is not necessarily modified with silicone.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
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  • Condensed Matter Physics & Semiconductors (AREA)
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  • Structures Or Materials For Encapsulating Or Coating Semiconductor Devices Or Solid State Devices (AREA)

Abstract

本発明によるパワー半導体モジュールは、金属ベース板と、上記金属ベース板上に配設され、電極を有する絶縁基板と、上記絶縁基板上に配設された半導体素子と、上記絶縁基板および上記半導体素子を取り囲むように上記金属ベース板に配設されたケースと、上記金属ベース板と上記ケースに囲まれた空間内に充填されて、上記絶縁基板および上記半導体素子を封止するポッティング封止剤と、を備え、上記ポッティング封止剤は、シリコーンゲルと、上記ゲルに添加された、シリコン原子とイオン性基を含む導電性付与剤と、を備える。

Description

パワー半導体モジュール
　この発明は、ケース内に配設された半導体素子をポッティング封止剤により封止してなるパワー半導体モジュールに関する。
　パワー半導体モジュールには、小型のパワー半導体モジュールに多く見られるトランスファー封止型と、中型以上のパワー半導体モジュールに多く見られるポッティング封止型（ケース型とも言う）がある。
　従来のポッティング封止型のパワー半導体モジュールは、金属ベース板と金属ベース板を囲む枠状のケース壁とからなるケースと、電極を有し、金属ベース板上に固定されてケース内に配設されたセラミック基板と、セラミック基板上に取りつけられた半導体素子と、セラミック基板の電極と半導体素子とを電気的に接続するワイヤと、ケース内に充填されて、ケース内の各部品を封止するポッティング封止剤であるシリコーンゲルと、ケース上部の開口部を塞ぐ蓋と、を備えている。
　近年、パワー半導体モジュールの高耐電圧化が進んでおり、現在６．５ｋＶ耐圧の製品が電車などに適用されている。素子内リーク電流を小さくして耐電圧を向上する手法として、通常、素子の周囲にガードリングを設け、その部分で電界緩和しながら半導体素子表面での電荷蓄積を小さくする手法がとられていた。また、コストを下げるため、素子サイズを小型化する検討もなされている。素子サイズを小型化する手段として、素子周辺のガードリングを縮小することが考えられるが、その結果、素子内部でのリーク電流が増大することが考えられる。さらに、電圧が高くなると、電荷がワイヤから継続的に放出されるため、ガードリングの形成領域に電荷が蓄積され、十分な電界緩和ができなくなることも課題である。
　このような状況を鑑み、封止剤より低帯電の絶縁性の低帯電材をワイヤの周囲に配設して、ワイヤから封止剤への電荷注入を抑制し、素子内部で発生するリーク電流の発生を抑制していた（例えば、特許文献１参照）。
　また、ポッティング封止剤を２層にし、下層（素子、基板側）に半導電性粒子を分散させることで、絶縁抵抗に非線形性を持たせ、電界の高い部分の電界緩和を可能としていた（例えば、特許文献２参照）。
　また、イオン液体が添加されたイオンゲルを絶縁基板の主面と絶縁基板の主面上に配置された導体板の側面との交差部に塗布し、その後、イオン液体が添加されていないゲルで全体を被覆することで、絶縁基板の沿面の電界を緩和し、その部分での放電の抑制を可能としていた（例えば、特許文献３参照）。
特開２００７－３０５７５７号公報 特開平１０－２７０６０９号公報 特開２００１７－２８１３２号公報
　特許文献１に記載のものでは、低帯電材をワイヤの周囲に配設しているが、多数本のワイヤは密集して配線されているため、ワイヤの周囲に低帯電材を配設する作業が煩雑であり、実用的ではなかった。
　特許文献２に記載のものでは、ポッティング封止剤を２層化する必要があるためコストが高くなるという課題があった。また、半導電性粒子を分散させたポッティング封止剤は絶縁抵抗に非線形性を有するため、電界集中している場所でしか電界緩和できず、しかもある電界を超えると急激に絶縁抵抗が低下するので、モジュール自体の耐電圧低下を起こしてしまう課題があった。さらに、ポッティング封止剤としてエポキシ樹脂を用いているので、半導電性粒子が添加されたエポキシ樹脂における硬化収縮の影響でセラミック基板にクラックを発生させてしまうという課題があった。
　特許文献３に記載のものでは、イオン液体が添加されていないゲルがイオンゲルを覆っている。そのため、イオンゲルに含まれるイオン液体が、イオン液体が添加されていないゲルに拡散し、イオンゲル中のイオン濃度が徐々に低下し、本来の電界緩和力が失われてしまうという課題があった。また、特許文献３に記載のものにおけるイオンゲルの塗布位置では、半導体素子のガードリング上に蓄積される電荷を減少させることはできない。
　この発明は、このような課題を解決するためになされたものであり、絶縁基板のクラック発生およびモジュールの耐電圧低下を抑制でき、ガードリング上での電界集中を抑制し、素子内部空欠層内で発生する素子内リーク電流を低減できるとともに、ポッティング封止剤の電界緩和力を長期的に維持できる、安価なパワー半導体モジュールを提供することを目的とする。
　この発明に係るパワー半導体モジュールは、金属ベース板と、上記金属ベース板上に配設され、電極を有する絶縁基板と、上記絶縁基板上に配設された半導体素子と、上記絶縁基板および上記半導体素子を取り囲むように上記金属ベース板に配設されたケースと、上記金属ベース板と上記ケースに囲まれた空間内に充填されて、上記絶縁基板および上記半導体素子を封止するポッティング封止剤と、を備え、上記ポッティング封止剤は、シリコーンゲルと、上記シリコーンゲルに添加された、シリコン原子とイオン性基を含む導電性付与剤と、を備える。
　この発明に係るパワー半導体モジュールによれば、ポッティング封止剤を２層化する必要がないので、安価となる。シリコーンゲルに含まれる導電性付与剤の濃度が均一であり、拡散によるシリコーンゲル中のイオン濃度の低下がなく、ポッティング封止剤の電界緩和力が長期的に維持される。ポッティング封止剤がゲルであるので、絶縁基板のクラック発生を抑制できる。ポッティング剤がゲルに導電性付与剤を添加して構成されているので、ポッティング封止剤と半導体素子との界面絶縁抵抗が下がり、界面での蓄積電荷量が低減し、素子内部の素子リーク電流を低減できる。また、ポッティング封止剤の導電性は、モジュールの絶縁を低下させるほど大きくなく、むしろ電界集中を緩和させるように作用し、モジュール自体の耐電圧の低下が抑制される。
この発明の一実施の形態に係るパワー半導体モジュールを示す断面図である。 この発明の一実施の形態に係るパワー半導体モジュールにおける半導体素子を示す上面図である。 比較例のパワー半導体モジュールにおけるガードリング周りの電荷蓄積と空乏層境界線の状態を説明する要部断面図である。 この発明の一実施の形態に係るパワー半導体モジュールにおけるガードリング周りの電荷蓄積と空乏層境界の状態を説明する要部断面図である。 導電性付与剤が未添加のシリコーンゲルでポッティングされたＩＧＢＴ素子の素子リーク電流を測定した結果を示す図である。 導電性付与剤が添加されたシリコーンゲルでポッティングされたＩＧＢＴ素子の素子リーク電流を測定した結果を示す図である。 櫛形電極基板を示す上面図である。 櫛形電極基板の界面絶縁抵抗の測定方法を説明する模式図である。 櫛形電極基板における櫛形電極界面リーク電流と電圧印加時間との関係を示す図である。 評価モジュールにおける金属ベース板に半導体素子が実装された状態を示す上面図である。 評価モジュールのモジュール組立体を示す断面図である。 評価モジュールに用いられるポッティング封止剤で封止された櫛形電極基板における櫛形電極界面リーク電流と電圧印加時間との関係を示す図である。 評価モジュールの評価結果を示す図である。
　実施の形態．
　図１はこの発明の一実施の形態に係るパワー半導体モジュールを示す断面図、図２はこの発明の一実施の形態に係るパワー半導体モジュールにおける半導体素子を示す上面図である。
　図１において、パワー半導体モジュール１００は、金属ベース板５と、金属ベース板５上に接合されて配設されたＤＢＣ（Ｄｉｒｅｃｔ　Ｂｏｎｄ　Ｃｏｐｐｅｒ）基板３と、ＤＢＣ基板３上に接合されて配設された半導体素子６と、外部と電気的に接続するための複数の外部端子２と、外部端子２、ＤＢＣ基板３、半導体素子６などの部品を取り囲むように金属ベース板５上に取りつけられたケース７と、金属ベース板５とケース７とで構成される空間内に充填されて、ＤＢＣ基板３、半導体素子６などの部品を封止するポッティング封止剤１と、ケース７の上部開口を塞ぐ蓋８と、を備える。
　ＤＢＣ基板３は、絶縁基板３ａの両面に、銅又は銅合金で形成された回路層を直接接合して構成されている。絶縁基板３ａは、セラミックス基板などにより構成されている。絶縁基板３ａの上面に配設されている回路網が上電極３ｂであり、絶縁基板３ａの下面に配設されている回路網が下電極３ｃである。半導体素子６は、ＩＧＢＴ、ＭＯＳＦＥＴなどパワー半導体素子である。
　金属ベース板５とＤＢＣ基板３との接合、ＤＢＣ基板３と半導体素子６との接合には、半田を用いた接合、金属ナノ粒子を用いた接合、金属拡散による接合、超音波による接合などが用いられる。半導体素子６の間、半導体素子６とＤＢＣ基板３の上電極３ｂとの間は、ワイヤボンディングにより、すなわちワイヤ９により電気的に接続されている。
　半導体素子６には、ガードリング１１と呼ばれる電界緩和パターンが形成されている。ガードリング１１は、図２に示されるように、半導体素子６の表面の外周縁部を周回するように形成された、互いに離間する複数本の導電性リングにより構成されている。電極１０が、半導体素子６の表面のガードリング１１に囲まれた領域に形成されている。ガードリング１１の本数は、半導体素子６の種類により適宜設定される。さらに、電界緩和用の半導電性のＳｉｎＳｉＮ膜（ｓｅｍｉ－ｉｎｓｕｌａｔｉｎｇ　Ｓｉｌｉｃｏｎ　Ｎｉｔｒｉｄｅ膜）がＣＶＤにより半導体素子６の表面のガードリング１１の導電性リング間に成膜されている。
　ポッティング封止剤１は、ゲルに導電性付与剤を添加して構成され、ポッティング封止剤１と半導体素子６との界面絶縁抵抗を下げている。ゲルは、分散質のネットワークにより高い粘性を持ちかつ流動性を失い、系全体としては固体状になったものである。ポッティング封止剤１のゲルは、ワイヤ９に作用する応力が小さく、ワイヤボンディングの長期信頼性を確保する観点から、低弾性率の材料を用いることが好ましく、ここでは、シリコーンゲルを用いている。シリコーンゲルは、付加型でも、縮合型でもよい。また、シリコーンゲルは、ジメチルポリシロキサン系でも、メチルフェニルポリシロキサン系でもよい。
　導電性付与剤は、シリコーンゲルと相溶する必要があるので、シリコーン変性イオン性液体が好ましい。つまり、導電性付与剤は、シリコン原子と、イオン性基と、を含んでいる。シリコーン変性イオン性液体は、硬化前のシリコーンゲルと相溶するが、シリコーンゲルが硬化すると、半導体素子および基板の表面に集まる特性を持つ。そこで、ポッティング封止剤１の体積絶縁抵抗を過度に下げることなく、ポッティング封止剤１と半導体素子およびポッティング封止剤１と基板との界面絶縁抵抗だけを下げることができるので、シリコーン変性イオン性液体の添加量が少なくてすむ。
　ポッティング封止剤１はシリコーンゲルに導電性付与剤を添加して構成されているので、ポッティング封止剤１は絶縁抵抗に非線形を有していない。そこで、特許文献２で課題となっている非導電性粒子を分散させることに起因するモジュール自体の耐電圧低下の発生を抑制することができる。また、ポッティング封止剤１は、モジュールの絶縁を低下させるほど大きくなく、むしろ電界集中を緩和するように作用する。これにより、モジュール自体の耐電圧低下を抑制することができる。
　金属ベース板５とケース７とで構成される空間内に充填されたポッティング封止剤１は、イオン性液体を含まないゲルにより覆われていない。また、ポッティング封止剤１中の導電性付与剤の濃度は均一である。そのため、ポッティング封止剤１中の導電性付与剤の濃度の低下が抑制され、電界緩和力が長期的に維持される。
　なお、シリコーン変性していない導電性付与剤は、シリコーンゲルと相溶しないため、分離してしまう。例えば、シリコーン変性していない導電性付与剤であるイオン性液体のエンスタットＰＲ－ＩＬ１（化研産業株式会社の製品名）をシリコーンゲルに添加した場合、シリコーンゲルと相溶しなかった。
　つぎに、本発明に係るパワー半導体モジュールによる素子内リーク電流の低減効果、および耐電圧向上について図３および図４を参照しつつ説明する。図３は比較例のパワー半導体モジュールにおけるガードリング周りの電荷蓄積と空乏層境界線の状態を説明する要部断面図、図４はこの発明の一実施の形態に係るパワー半導体モジュールにおけるガードリング周りの電荷蓄積と空乏層境界の状態を説明する要部断面図である。
　比較例のパワー半導体モジュール２００では、図３に示されるように、アルミ電極１２、Ｐ層１３、Ｎ－層１４、Ｎ＋層１５、ＳｉＯ2、ＰＳＧおよびＳｉｎＳｉＮからなる層間膜１６により構成された半導体素子６が、導電性付与剤が添加されていないポッティング封止剤としてのシリコーンゲル２０により封止されている。本願のパワー半導体モジュール１００では、図４に示されるように、同様に構成された半導体素子６が、導電性付与剤をシリコーンゲルに添加してなるポッティング封止剤１により封止されている。なお、シリコーンゲル２０は、ポッティング封止剤１を構成するシリコーンゲルと同じものである。
　比較例のパワー半導体モジュール２００では、電荷がワイヤから継続的に放出されるため、ワイヤ９から放出されてガードリング１１の領域に到達した電荷が移動せず、蓄積される。つまり、図３に示されるように、アルミ電極１２からなるガードリング１１の領域において、＋可動イオン１７および－可動イオン１８からなる電荷が、半導体素子６とシリコーンゲル２０との界面に蓄積される。この蓄積された電荷が、空欠層境界１９を外側に押し込む。これにより、半導体素子６の素子内部空欠層内で発生する素子内リーク電流が大きくなる。また、空欠層境界１９の変形が、ガードリング１１を構成するアルミ電極１２間の電界の不均一、すなわち電界集中を招く。電界が集中した部分では、絶縁破壊を発生する可能性がある。
　本出願人が検討したところ、ＳｉｎＳｉＮ膜の電気抵抗の温度依存性が大きいため、低温で電気抵抗が上がることが確認された。そこで、比較例のパワー半導体モジュール２００では、低温となり、ＳｉｎＳｉＮ膜が高抵抗となると、ワイヤ９から放出されてガードリング１１の領域に到達した電荷が移動せず、電荷の蓄積が促進される。これにより、低温域では、半導体素子６の素子内部空欠層内で発生する素子内リーク電流が一層大きくなってしまう。
　本願のパワー半導体モジュール１００では、ポッティング封止剤１が半導体素子６の表面および半導体素子６の表面の外周縁部にあるガードリング１１に接している。そこで、シリコーンゲルに添加された導電性付与剤が半導体素子６の表面に集まり、半導体素子６とポッティング封止剤１との間の界面絶縁抵抗が下がっている。これにより、ワイヤ９から放出されてガードリング１１の領域に到達した電荷が速やかに移動し、電界の蓄積が緩和される。つまり、図４に示されるように、ガードリング１１を構成するアルミ電極１２間の領域において、半導体素子６とポッティング封止剤１との界面に蓄積される電荷が、緩和され、少なくなる。そこで、空欠層境界１９が正常な形を保持し、素子内部空欠層内で発生する素子内リーク電流の増大が抑制される。
　また、仮に低温となっても、低温となることに起因するＳｉｎＳｉＮ膜の抵抗の上昇は、半導体素子６とポッティング封止剤１との間の界面絶縁抵抗の低下により補完される。そこで、半導体素子６とポッティング封止剤１との界面に蓄積される電荷が、緩和され、少なくなる。これにより、低温域でも、素子内部空欠層内で発生する素子内リーク電流の増大が抑制される。
　つぎに、半導体素子であるＩＧＢＴ素子の素子リーク電流を測定した結果を図５および図６に示す。図５は導電性付与剤が未添加のシリコーンゲルでポッティングされたＩＧＢＴ素子の素子リーク電流を測定した結果を示す図、図６は導電性付与剤が添加されたシリコーンゲルでポッティングされたＩＧＢＴ素子の素子リーク電流を測定した結果を示す図である。なお、素子リーク電流の測定は、室温で１チップで行った。ここでの評価は、素子内リーク電流だけを分けて測定して行うものではない。すなわち、ここでの素子リーク電流は、素子内リーク電流を包含している。
　ポッティング封止剤として導電性付与剤が未添加のシリコーンゲルを用いた場合、図５に示されるように、電圧印加後約１ｆｓで、素子リーク電流が２０ｍＡを超えていた。一方、ポッティング封止剤として導電性付与剤が添加されたシリコーンゲルを用いた場合、図６に示されるように、素子リーク電流は約５ｍＡを超えることがなかった。このように、ポッティング封止剤として導電性付与剤をゲルに添加して、ポッティング封止剤と素子との界面絶縁抵抗を下げることで、素子リーク電流を低減できることが確認された。
　ここで、ゲルに添加する導電性付与剤の最適値は、導電性付与剤の化学構造、ゲルの化学構造などによって異なるため、最適値を添加量で規定することは困難となる。そこで、本出願人は、セラミック基板の表面に櫛形対向電極パターンを形成した櫛形電極基板をポッティング封止剤で封止する構成におけるポッティング封止剤と基板との界面絶縁抵抗（電流値）で導電性付与剤の最適値を規定することに着眼した。また、界面絶縁抵抗が過度に低くなると、ポッティング封止剤と基板との界面で電流が流れて、絶縁不良を引き起こすことになる。そこで、本出願人は、導電性付与剤の最適添加量の範囲を添加量ではなく、導電性付与剤の添加後のポッティング封止剤と基板との界面絶縁抵抗の範囲で規定できると判断した。
　つぎに、ポッティング封止剤と基板との界面絶縁抵抗の範囲について検討する。図７は櫛形電極基板を示す上面図、図８は櫛形電極基板の界面絶縁抵抗の測定方法を説明する模式図、図９は櫛形電極基板における櫛形電極界面リーク電流と電圧印加時間との関係を示す図である。
　評価基板である櫛形電極基板２１は、図７に示されるように、絶縁基板２２の一面に銅を接合して構成されたＤＢＣ基板の一面にニッケルめっきを施し、エッチングによりパターニングして、櫛形対向電極パターン２３を形成して、作製される。そこで、櫛形対向電極パターン２３はニッケルと銅の２層構造となっている。絶縁基板２２は、４５．２ｍｍ×３４ｍｍ×０．６３５ｍｍの窒化ケイ素基板である。櫛形対向電極パターン２３は、一対の電極の櫛が１ｍｍ離間して交互に配列されたパターンである。
　界面絶縁抵抗の測定は、図８に示されるように、櫛形電極基板２１がケース２４内に収納され、ポッティング封止剤２５により封止された状態で行った。そして、櫛形電極基板２１の櫛形対向電極パターン２３の各電極引き出し部２３ａから引き出された電極線２７，２８がハイレジスタンスメータ２６に接続される。そして、電極線２７，２８に１ｋＶの直流電圧を印加して、櫛形電極基板２１とポッティング封止剤２５の櫛形電極界面リーク電流を測定し、その結果を図９に示す。図９では、ＳＥ－１８８５（東レ・ダウコーニング株式会社の製品名）にＸ－４０－２４５０（信越化学工業の製品名）を０．００００５重量％添加してなるポッティング封止剤２５を用いた場合を実線で示し、ポッティング封止剤２５としてシリコーンゲルのみを用いた場合を点線で示した。なお、ＳＥ－１８８５は、硬化してシリコーンゲルとなる。また、Ｘ－４０－２４５０は、イオン性液体をシリコーン変性したイオン性基含有シリコーンオリゴマー（シリコーン変性イオン性液体）であり、イオン性基はビストリフルオロメタンスルホンイミドであり、導電性付与剤として機能する。
　図９から、ポッティング封止剤２５として、導電性付与剤がシリコーンゲルに添加された封止剤を用いた場合、電圧印加後、櫛形電極界面リーク電流は、時間と共に小さくなった後、ほぼ一定の値に安定していることがわかった。これにより、少量の導電性付与剤の添加で界面絶縁抵抗が下がることがわかった。
　また、図９から、ポッティング封止剤２５として、導電性付与剤が未添加のシリコーンゲルを用いた場合、電圧印加直後では大きな櫛形電極界面リーク電流が流れ、その後櫛形電極界面リーク電流が徐々に小さくなり、３００秒後にほぼ一定の値に安定することがわかった。すなわち、経時変化を考慮して、３００秒後の櫛形電極界面リーク電流値で界面絶縁抵抗値を判断することが好ましい。これにより、吸収電流の影響を受けることなく、界面絶縁抵抗値を判断できる。
　以下、導電性付与剤の添加量を変えてパワー半導体モジュールを作製し、それらの性能を評価した結果を説明する。図１０は評価モジュールの金属ベース板に半導体素子が実装された状態を示す上面図、図１１は評価モジュールのモジュール組立体を示す断面図、図１２は評価モジュールに用いられるポッティング封止剤で封止された櫛形電極基板における櫛形電極界面リーク電流と電圧印加時間との関係を示す図、図１３は評価モジュールの評価結果を示す図である。
　金属ベース板５は、１９０ｍｍ×１４０ｍｍ×３ｍｍの銅板を用いた。ＤＢＣ基板３は、５１ｍｍ×３０ｍｍ×１ｍｍの窒化ケイ素からなる絶縁基板３ａの両面に銅により形成された回路網が直接接合されたものを用いた。ＤＢＣ基板３に搭載する半導体素子６は、ＩＧＢＴ６ａとＦＷＤ（Ｆｒｅｅ　Ｗｈｅｅｌｉｎｇ　Ｄｉｏｄｅ）６ｂを用いた。ポッティング封止剤１のゲルには、硬化してシリコーンゲルとなるＳＥ－１８８５を用いた。導電性付与剤は、Ｘ－４０－２４５０を用いた。
　そして、図１０に示されるように、６枚のＤＢＣ基板３を金属ベース板５上に実装し、ＩＧＢＴ６ａとＦＷＤ６ｂとを各ＤＢＣ基板３に３つずつ実装した。ワイヤボンディングによりＤＢＣ基板３間などを電気的に接続した。図１１に示されるように、枠状のケース７を、ＤＢＣ基板３を取り囲むように、金属ベース板５に取りつけて、モジュール組立体１１０を作製した。
　ＳＥ－１８８５のＡ液とＢ液とを２００ｇずつ計量し、攪拌混合した。ついで、Ｘ－４０－２４５０の所定量を攪拌混合されたＳＥ－１８８５に添加し、２分間減圧脱泡した。ついで、Ｘ－４０－２４５０が添加されたＳＥ－１８８５をモジュール組立体に減圧注入し、１００℃のオーブンに入れて１時間加熱し、Ｘ－４０－２４５０が添加されたＳＥ－１８８５を硬化させた。この固化物がポッティング封止剤１であり、ＳＥ－１８８５の固化物がシリコーンゲルである。ついで、モジュール組立体１１０の上部開口を蓋８で塞ぎ、図１に示されるパワー半導体モジュール１００と同等の評価モジュールを作製した。ここでは、Ｘ－４０－２４５０の添加量を、０．１ｗｔ％、０．０５ｗｔ％、０．００５ｗｔ％、０．００１ｗｔ％、０．０００５ｗｔ％、０．０００１ｗｔ％、０．００００５ｗｔ％、０．００００１ｗｔ％、０．０００００１ｗｔ％とした９種類の評価モジュールを作製した。
　室温での素子リーク電流と交流による部分放電との２項目で評価モジュールの評価を行い、その評価結果を図１３に示した。素子リーク電流の評価は、室温で、評価モジュールに５２００ＶのＤＣ電圧を印加して素子リーク電流を計測して行った。そして、図５および図６の検討結果を考慮して、素子リーク電流の計測値が２０ｍＡ未満の場合を合格とした。部分放電の評価は、評価モジュールに印加する電圧を、５ｋＶステップで、３０秒インターバルで昇圧させ、放電電荷を計測して行った。そして、放電電荷の計測値が１０ｐＣ以上になる電圧が１１．５ｋＶ以下の場合を合格とした。また、放電が発生しない場合でも、すなわち電圧が１１．５ｋＶ以下の場合でも、電流値が５０ｍＡ以上であれば、絶縁試験不合格とした。
　Ｘ－４０－２４５０の添加量を変えた９種類のポッティング封止剤１により図７に示される櫛形電極基板２１を封止し、図８に示される測定方法により、櫛形電極基板２１における櫛形電極界面リーク電流を測定し、その測定結果を図１２に示す。また、櫛形電極基板２１に電圧を印加してから３００秒後の櫛形電極界面リーク電流の測定値を図１３に示した。この櫛形電極界面リーク電流の測定値は、ポッティング封止剤１を用いた界面の絶縁抵抗を電流値で表したものである。
　図１２から、導電性付与剤であるＸ－４０－２４５０の添加量が多くなるほど、櫛形電極界面リーク電流が大きくなることがわかった。すなわち、導電性付与剤であるＸ－４０－２４５０の添加量を多くするほど、界面の絶縁抵抗が低くなることが確認できた。
　図１３から、導電性付与剤であるＸ－４０－２４５０の添加量が０．００００１ｗｔ％以上であると、素子リーク電流が２０ｍＡ未満であったが、添加量が０．０００００１ｗｔ％以下となると、素子リーク電流が２０ｍＡ以上となることがわかった。これは、添加量を０．０００００１ｗｔ％以下とすることで、界面絶縁抵抗が低くなりすぎ、ワイヤ９から放出されてガードリング１１の領域に到達した電荷が蓄積されて、素子リーク電流が増加したものと、推考される。
　図１３から、導電性付与剤であるＸ－４０－２４５０の添加量が０．００５ｗｔ％より多くなると、部分放電および絶縁不良が発生することがわかった。これは、添加量を０．００５ｗｔ％より多くすることで、界面絶縁抵抗が高くなりすぎ、ゲルと半層体素子との界面、基板の沿面などで電流がリークしたことによるものと、推考される。
　これらのことから、導電性付与剤であるＸ－４０－２４５０の添加量を、０．００５Ｗｔ％以下、０．００００１ｗｔ％以上とすることが好ましい。また、Ｘ－４０－２４５０の添加量が０．００５Ｗｔ％のとき、櫛形電極界面リーク電流は１．５×１０-8Ａであり、Ｘ－４０－２４５０の添加量が０．００００１Ｗｔ％のとき、櫛形電極界面リーク電流は４．２×１０-10Ａであった。
　しかし、導電性付与剤の添加量の最適値は、導電性付与剤の化学構造、ゲルの化学構造などによって異なる。そこで、櫛形電極界面リーク電流が、１．５×１０-8Ａ以下、４．２×１０-10Ａ以上となるように、導電性付与剤の添加量を調整すればよい。
　ここでは、導電性付与剤としてＸ－４０－２４５０を用いたが、導電性付与剤は、Ｘ－４０－２４５０に限定されず、シリコーンゲルと相溶するイオン性液体、すなわちシリコーン変性イオン性溶液であればよい。
　また、ゲルとしてシリコーンゲルを用いたが、ゲルはシリコーンゲルに限定されず、低弾性率のゲルであればよい。この場合、導電性付与剤は、ゲルと相溶するイオン性液体を用いればよく、必ずしもシリコーン変性している必要はない。
　１　ポッティング封止剤、３　絶縁基板、５　金属ベース板、６　半導体素子、７　ケース、１１　ガードリング、２１　櫛形電極基板（評価基板）、２２　絶縁基板（窒化ケイ素基板）、２３　櫛形対向電極パターン。

Claims (4)

  1. 　金属ベース板と、上記金属ベース板上に配設され、電極を有する絶縁基板と、上記絶縁基板上に配設された半導体素子と、上記絶縁基板および上記半導体素子を取り囲むように上記金属ベース板に配設されたケースと、上記金属ベース板と上記ケースに囲まれた空間内に充填されて、上記絶縁基板および上記半導体素子を封止するポッティング封止剤と、を備えたパワー半導体モジュールにおいて、
    　上記ポッティング封止剤は、シリコーンゲルと、上記シリコーンゲルに添加された、シリコン原子とイオン性基を含む導電性付与剤と、を備えるパワー半導体モジュール。
  2. 　上記ポッティング封止剤は、前記半導体素子の表面の外周縁部にあるガードリングに接している請求項１記載のパワー半導体モジュール。
  3. 　上記ポッティング封止剤は、櫛を１ｍｍ間隔で交互に配列してなる櫛形対向電極パターンが窒化ケイ素基板上に形成されている評価基板が上記ポッティング封止剤で封止されている状態で、上記櫛形対向電極パターンの電極間に１ｋＶの直流電圧を印加してから３００秒後の櫛形電極界面リーク電流が、１．５×１０-8Ａ以下、４．２×１０-10Ａ以上である請求項１又は請求項２記載のパワー半導体モジュール。
  4. 　上記イオン性基は、ビストリフルオロメタンスルホンイミドである請求項１から請求項３のいずれか１項に記載のパワー半導体モジュール。
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10173101A (ja) * 1996-12-10 1998-06-26 Toshiba Corp 半導体装置
JP2007305757A (ja) * 2006-05-11 2007-11-22 Mitsubishi Electric Corp 半導体装置
JP2013245236A (ja) * 2012-05-23 2013-12-09 Shin-Etsu Chemical Co Ltd シリコーンゴム組成物
JP2015511969A (ja) * 2012-01-04 2015-04-23 モメンティブ パフォーマンス マテリアルズ インコーポレイテッド イオン性シリコーンの硬化性組成物
JP2015207731A (ja) * 2014-04-23 2015-11-19 三菱電機株式会社 半導体装置
JP2017028132A (ja) * 2015-07-23 2017-02-02 富士電機株式会社 半導体モジュール及び半導体モジュールの製造方法

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3223835B2 (ja) 1997-03-28 2001-10-29 三菱電機株式会社 パワー半導体装置及びその製造方法
JP3703978B2 (ja) 1998-11-13 2005-10-05 株式会社東芝 半導体装置
US20110287316A1 (en) * 2010-05-21 2011-11-24 Ada Technologies, Inc. High performance carbon nano-tube composites for electrochemical energy storage devices
US8963321B2 (en) * 2011-09-12 2015-02-24 Infineon Technologies Ag Semiconductor device including cladded base plate
US8519532B2 (en) * 2011-09-12 2013-08-27 Infineon Technologies Ag Semiconductor device including cladded base plate
JP5987297B2 (ja) * 2011-11-10 2016-09-07 富士電機株式会社 パワー半導体装置の製造方法
US20130172192A1 (en) * 2012-01-04 2013-07-04 Momentive Performance Materials Inc. Ionically cross-linked silicone composition
WO2018047551A1 (ja) * 2016-09-09 2018-03-15 富士電機株式会社 半導体装置製造方法及び半導体装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10173101A (ja) * 1996-12-10 1998-06-26 Toshiba Corp 半導体装置
JP2007305757A (ja) * 2006-05-11 2007-11-22 Mitsubishi Electric Corp 半導体装置
JP2015511969A (ja) * 2012-01-04 2015-04-23 モメンティブ パフォーマンス マテリアルズ インコーポレイテッド イオン性シリコーンの硬化性組成物
JP2013245236A (ja) * 2012-05-23 2013-12-09 Shin-Etsu Chemical Co Ltd シリコーンゴム組成物
JP2015207731A (ja) * 2014-04-23 2015-11-19 三菱電機株式会社 半導体装置
JP2017028132A (ja) * 2015-07-23 2017-02-02 富士電機株式会社 半導体モジュール及び半導体モジュールの製造方法

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