JP2013182983A - Silicon nitride circuit board and module using the same - Google Patents
Silicon nitride circuit board and module using the same Download PDFInfo
- Publication number
- JP2013182983A JP2013182983A JP2012045202A JP2012045202A JP2013182983A JP 2013182983 A JP2013182983 A JP 2013182983A JP 2012045202 A JP2012045202 A JP 2012045202A JP 2012045202 A JP2012045202 A JP 2012045202A JP 2013182983 A JP2013182983 A JP 2013182983A
- Authority
- JP
- Japan
- Prior art keywords
- silicon nitride
- circuit board
- substrate
- circuit
- nitride substrate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229910052581 Si3N4 Inorganic materials 0.000 title claims abstract description 59
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 title claims abstract description 59
- 239000000758 substrate Substances 0.000 claims abstract description 85
- 229910052751 metal Inorganic materials 0.000 claims abstract description 45
- 239000002184 metal Substances 0.000 claims abstract description 45
- 230000015556 catabolic process Effects 0.000 claims abstract description 20
- 239000011148 porous material Substances 0.000 claims abstract description 15
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 claims abstract description 9
- 229910052753 mercury Inorganic materials 0.000 claims abstract description 9
- 238000002459 porosimetry Methods 0.000 claims abstract description 4
- 239000000919 ceramic Substances 0.000 abstract description 7
- 230000017525 heat dissipation Effects 0.000 abstract description 6
- 239000004065 semiconductor Substances 0.000 abstract description 5
- 238000009413 insulation Methods 0.000 abstract description 4
- 238000000034 method Methods 0.000 description 21
- 239000000843 powder Substances 0.000 description 20
- 238000005219 brazing Methods 0.000 description 12
- 239000000463 material Substances 0.000 description 12
- 229910052802 copper Inorganic materials 0.000 description 11
- 239000010949 copper Substances 0.000 description 11
- 238000005238 degreasing Methods 0.000 description 10
- 239000002994 raw material Substances 0.000 description 10
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 8
- 239000013078 crystal Substances 0.000 description 8
- 239000011230 binding agent Substances 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- 239000012298 atmosphere Substances 0.000 description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 6
- 230000005684 electric field Effects 0.000 description 5
- 238000010304 firing Methods 0.000 description 5
- 238000007747 plating Methods 0.000 description 5
- 239000002904 solvent Substances 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 239000011812 mixed powder Substances 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 238000005245 sintering Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 239000002245 particle Substances 0.000 description 3
- 238000005498 polishing Methods 0.000 description 3
- 230000003746 surface roughness Effects 0.000 description 3
- 229910052582 BN Inorganic materials 0.000 description 2
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 description 2
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- WUOACPNHFRMFPN-UHFFFAOYSA-N alpha-terpineol Chemical compound CC1=CCC(C(C)(C)O)CC1 WUOACPNHFRMFPN-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 description 2
- 230000001186 cumulative effect Effects 0.000 description 2
- SQIFACVGCPWBQZ-UHFFFAOYSA-N delta-terpineol Natural products CC(C)(O)C1CCC(=C)CC1 SQIFACVGCPWBQZ-UHFFFAOYSA-N 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000003112 inhibitor Substances 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 239000004014 plasticizer Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000004439 roughness measurement Methods 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 229940116411 terpineol Drugs 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- QDOIZVITZUBGOQ-UHFFFAOYSA-N 1,1,2,2,3,3,4,4,4-nonafluoro-n,n-bis(1,1,2,2,3,3,4,4,4-nonafluorobutyl)butan-1-amine;1,1,2,2,3,3,4,4,4-nonafluoro-n-(1,1,2,2,3,3,4,4,4-nonafluorobutyl)-n-(trifluoromethyl)butan-1-amine Chemical compound FC(F)(F)C(F)(F)C(F)(F)C(F)(F)N(C(F)(F)F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)F.FC(F)(F)C(F)(F)C(F)(F)C(F)(F)N(C(F)(F)C(F)(F)C(F)(F)C(F)(F)F)C(F)(F)C(F)(F)C(F)(F)C(F)(F)F QDOIZVITZUBGOQ-UHFFFAOYSA-N 0.000 description 1
- DDFHBQSCUXNBSA-UHFFFAOYSA-N 5-(5-carboxythiophen-2-yl)thiophene-2-carboxylic acid Chemical compound S1C(C(=O)O)=CC=C1C1=CC=C(C(O)=O)S1 DDFHBQSCUXNBSA-UHFFFAOYSA-N 0.000 description 1
- 229910017944 Ag—Cu Inorganic materials 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910000881 Cu alloy Inorganic materials 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-M Methacrylate Chemical compound CC(=C)C([O-])=O CERQOIWHTDAKMF-UHFFFAOYSA-M 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000001154 acute effect Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000012752 auxiliary agent Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229960003280 cupric chloride Drugs 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000007606 doctor blade method Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 235000011187 glycerol Nutrition 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- 239000001866 hydroxypropyl methyl cellulose Substances 0.000 description 1
- 235000010979 hydroxypropyl methyl cellulose Nutrition 0.000 description 1
- 229920003088 hydroxypropyl methyl cellulose Polymers 0.000 description 1
- UFVKGYZPFZQRLF-UHFFFAOYSA-N hydroxypropyl methyl cellulose Chemical compound OC1C(O)C(OC)OC(CO)C1OC1C(O)C(O)C(OC2C(C(O)C(OC3C(C(O)C(O)C(CO)O3)O)C(CO)O2)O)C(CO)O1 UFVKGYZPFZQRLF-UHFFFAOYSA-N 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 239000003550 marker Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- SIWVEOZUMHYXCS-UHFFFAOYSA-N oxo(oxoyttriooxy)yttrium Chemical compound O=[Y]O[Y]=O SIWVEOZUMHYXCS-UHFFFAOYSA-N 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229920000205 poly(isobutyl methacrylate) Polymers 0.000 description 1
- 238000007639 printing Methods 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 230000007261 regionalization Effects 0.000 description 1
- 230000002040 relaxant effect Effects 0.000 description 1
- 238000007650 screen-printing Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 238000005382 thermal cycling Methods 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Landscapes
- Ceramic Products (AREA)
Abstract
【課題】パワー半導体素子からの熱を効率よく放散させるため、パワーモジュールに用いられる回路基板には、放熱性がよく、かつ絶縁破壊電圧や部分放電において、絶縁性の高いセラミックス基板を提供する。
【解決手段】窒化けい素基板１の一方の面に金属回路２、他方の面に金属放熱板３が形成されてなる回路基板において、窒化けい素基板が水銀圧入法による基板表面の直径１μｍ以上１００μｍ未満の細孔積算容積が０．０５ｃｍ３／ｇ以下（０を含まず）であることを特徴とする窒化けい素回路基板であり、回路端部から窒化けい素基板端部までの最短距離が０．８ｍｍ以上であり、回路端部から窒化けい素基板端部までの最短距離ｈ１と放熱板端部から窒化けい素基板端部までの最短距離ｈ２の差が０〜０．３ｍｍとすることにより、部分放電開始電圧が絶縁破壊電圧の９０％以上に向上する。
【選択図】図１To efficiently dissipate heat from a power semiconductor element, a circuit board used in a power module has a good heat dissipation and provides a ceramic substrate having high insulation in a breakdown voltage and partial discharge.
In a circuit board in which a metal circuit 2 is formed on one surface of a silicon nitride substrate 1 and a metal heat sink 3 is formed on the other surface, the silicon nitride substrate has a diameter of 1 μm or more on the surface of the substrate by mercury porosimetry. A silicon nitride circuit board having an integrated pore volume of less than 100 μm of 0.05 cm 3 / g or less (not including 0), and the shortest distance from the circuit end to the silicon nitride substrate end The difference between the shortest distance h1 from the circuit end to the silicon nitride substrate end and the shortest distance h2 from the heat sink end to the silicon nitride substrate end is 0 to 0.3 mm. As a result, the partial discharge start voltage is improved to 90% or more of the dielectric breakdown voltage.
[Selection] Figure 1
Description
本発明は、半導体を搭載する部材として使用され、具体的には、例えば電鉄、電気自動車、一般産業用のインバータ用モジュール等に用いられる窒化けい素回路基板に関するものである。 The present invention relates to a silicon nitride circuit board that is used as a member for mounting a semiconductor, specifically, for example, an electric railway, an electric vehicle, an inverter module for general industries, and the like.
エレクトロニクス技術の発展に伴い、パワーモジュール等に用いられる絶縁回路基板（以下、単に「回路基板」という。）が達成すべき今日の課題は、電気特性を一段と向上させることである。
回路基板は、セラミックス基板の表面に金属回路を、裏面に金属放熱板を有することを基本構造とし、上記金属回路と上記金属放熱板には、通常、無電解Ｎｉめっきが施される。Ｎｉめっきがないときは、防錆剤が施される。モジュールの組み立ては、回路基板の金属回路にパワー半導体素子と電極を、また金属放熱板面に放熱部材をはんだ付けしておこなわれる。
With the development of electronics technology, today's problem to be achieved by an insulated circuit board (hereinafter simply referred to as “circuit board”) used in power modules and the like is to further improve electrical characteristics.
The circuit board has a basic structure having a metal circuit on the surface of a ceramic substrate and a metal heat sink on the back, and the metal circuit and the metal heat sink are usually subjected to electroless Ni plating. When there is no Ni plating, a rust inhibitor is applied. The module is assembled by soldering the power semiconductor element and the electrode to the metal circuit of the circuit board and the heat radiating member to the metal heat radiating plate surface.
近年、ロボットやモーター等の産業機器の高性能化に伴い、大電力・高能率インバーター等のパワーモジュールの変遷が進んでおり、パワー半導体素子から発生する熱も増加の一途をたどっている。この熱を効率よく放散させるため、パワーモジュールに用いられる回路基板には、放熱性がよく、かつ絶縁性の高いセラミックス基板が多数使用されているが、大電力・高出力化に伴って電気特性、すなわち、絶縁破壊電圧や部分放電について、これらの向上を強く要望されている。 In recent years, with the improvement in performance of industrial equipment such as robots and motors, the transition of power modules such as high-power and high-efficiency inverters is progressing, and the heat generated from power semiconductor elements is steadily increasing. In order to dissipate this heat efficiently, the circuit boards used in power modules use many ceramic substrates with good heat dissipation and high insulation properties. That is, there is a strong demand for improving the breakdown voltage and partial discharge.
従来、部分放電特性の向上に関しては、接合層のはみ出し部を長くする提案（特許文献１）、金属回路のコーナー部の曲率半径を特定する提案（特許文献２）、また、セラミックス基板の両面に回路パターンを対称に形成する提案（特許文献３〜５）がなされているが、前記従来の構成では、回路形状に関する提案であって、金属回路を設計する際に反映できない場合もあり、十分な効果を得ることができていなかった。 Conventionally, regarding the improvement of partial discharge characteristics, a proposal to lengthen the protruding portion of the bonding layer (Patent Document 1), a proposal to specify the radius of curvature of the corner portion of the metal circuit (Patent Document 2), and both surfaces of the ceramic substrate Proposals for forming circuit patterns symmetrically (Patent Documents 3 to 5) have been made. However, the conventional configuration is a proposal related to a circuit shape, and may not be reflected when designing a metal circuit. The effect was not able to be acquired.
本発明の目的は、前記従来の課題である電気特性を一段と向上させることであり、具体的には、窒化けい素回路基板の部分放電開始電圧（１０ｐｃ以上となる電圧）を絶縁破壊電圧の８５％以上に向上することである。 An object of the present invention is to further improve the electrical characteristics, which is the conventional problem. Specifically, the partial discharge start voltage (voltage at 10 pc or higher) of the silicon nitride circuit board is set to 85 of the breakdown voltage. % Or more.
本発明の回路基板は、窒化けい素基板の一方の面に金属回路、他方の面に金属放熱板がそれぞれ活性金属を含むろう材層を介して接合されてなるものであって、回路基板に使用される窒化けい素基板は、水銀圧入法にて測定した基板表面の直径１μｍ以上１００μｍ未満の細孔積算容積が０．０５ｃｍ３／ｇ以下（０を含まず）であることを特徴とする回路基板であることを特徴とするものである。
さらに本発明の前記回路基板において、回路端部から窒化けい素基板端部までの最短距離が０．８ｍｍ以上であり、回路端部から窒化けい素基板端部までの最短距離と放熱板端部から窒化けい素基板端部までの最短距離の差が０〜０．３ｍｍであることを特徴とする部分放電開始電圧が絶縁破壊電圧の９０％以上である回路基板であり、該回路基板を具備することを特徴とするモジュールである。
The circuit board of the present invention is formed by joining a metal circuit to one surface of a silicon nitride substrate and a metal heat sink to the other surface via a brazing material layer containing an active metal. The silicon nitride substrate used is characterized in that the integrated pore volume with a diameter of 1 μm or more and less than 100 μm of the substrate surface measured by mercury porosimetry is 0.05 cm 3 / g or less (excluding 0). It is a circuit board.
Furthermore, in the circuit board of the present invention, the shortest distance from the circuit end to the silicon nitride substrate end is 0.8 mm or more, and the shortest distance from the circuit end to the silicon nitride substrate end and the end of the heat sink A partial discharge start voltage is 90% or more of a dielectric breakdown voltage, characterized in that the difference in the shortest distance from the silicon nitride substrate end to 0 to 0.3 mm is provided. It is a module characterized by doing.
本発明によれば、電気特性すなわち部分放電特性を一段と向上させた窒化けい素回路基板及びそれを用いたモジュールを提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the silicon nitride circuit board which improved the electrical characteristic, ie, a partial discharge characteristic, and a module using the same can be provided.
以下、本発明について詳細に説明する。 The present invention will be described in detail below.
本発明で用いられるセラミックス基板の材質は、機械的強度と低熱抵抗を兼ね備えた窒化けい素であり、その基板の厚みは０．２〜１ｍｍが一般的であるが、目的によって変更される。たとえば、窒化けい素基板は、他のセラミックス基板よりも機械的強度が強いので、０．２〜０．５ｍｍに薄化し熱抵抗を小さくして用いることができる。これによって回路基板の薄化がより可能となるとともに回路基板の熱抵抗も小さくすることが可能となる。一方、高電圧用のモジュールに使用する場合、絶縁耐圧が重視されるために例えば０．５〜１ｍｍの厚物が用いられる。 The material of the ceramic substrate used in the present invention is silicon nitride having both mechanical strength and low thermal resistance, and the thickness of the substrate is generally 0.2 to 1 mm, but is changed depending on the purpose. For example, since a silicon nitride substrate has a higher mechanical strength than other ceramic substrates, it can be thinned to 0.2 to 0.5 mm and used with a reduced thermal resistance. As a result, the circuit board can be made thinner and the thermal resistance of the circuit board can be reduced. On the other hand, when used in a high voltage module, a thickness of, for example, 0.5 to 1 mm is used because the withstand voltage is important.
本発明で用いられる金属回路、金属放熱板の材質は、電気的・熱的特性の点から、アルミニウム、銅、銅合金、アルミニウム合金の単体又はこれらのクラッドが用いられる。熱サイクルによる信頼性を重視する場合は、硬度変化の少ないアルミニウムを選択することが好ましく、電気抵抗や過渡熱を重視する場合は、銅が好ましい。厚みは、金属回路、金属放熱板のいずれも０．１〜０．６ｍｍであることが好ましい。金属回路は、窒化けい素基板の表面に１又は２以上の適宜数が形成され、金属放熱板は、放熱性の観点から通常ベタ金属板が設けられるが、場合によっては、分割された放熱板を配置することもある。 As the material of the metal circuit and metal heat sink used in the present invention, aluminum, copper, copper alloy, aluminum alloy alone or a clad thereof is used from the viewpoint of electrical and thermal characteristics. When importance is attached to reliability by thermal cycling, it is preferable to select aluminum having a small change in hardness, and copper is preferable when importance is attached to electrical resistance and transient heat. The thickness is preferably 0.1 to 0.6 mm for both the metal circuit and the metal heat sink. The number of metal circuits is suitably one or two or more on the surface of the silicon nitride substrate, and the metal heat sink is usually provided with a solid metal plate from the viewpoint of heat dissipation, but in some cases, the heat sink is divided. May be arranged.
このとき、本発明に関する回路基板で重要なことは、水銀圧入法で測定した窒化けい素基板表面の直径１μｍ以上１００μｍ未満の細孔積算容積が０．０５ｃｍ３／ｇ以下（０を含まず）であることが肝要である。すなわち、該窒化けい素基板を回路基板に使用することにより、部分放電開始電圧が該回路基板の絶縁破壊電圧の８５％以上とすることができる。以下にその詳細について説明する。 At this time, what is important in the circuit board related to the present invention is that the integrated volume of pores having a diameter of 1 μm or more and less than 100 μm on the surface of the silicon nitride substrate measured by mercury porosimetry is 0.05 cm 3 / g or less (not including 0). It is important to be. That is, by using the silicon nitride substrate as a circuit board, the partial discharge start voltage can be 85% or more of the dielectric breakdown voltage of the circuit board. The details will be described below.
本発明の課題である部分放電は、回路基板の回路面、放熱面間に電圧を印加し、電圧を印加している金属回路にて電界の集中しやすい部分、例えば、端部の形状が鋭角な箇所や、局所的に曲率が小さな箇所で電界集中が発生し、電界密度の低い箇所に不規則、または連続して１０ｐＣ以上の電荷量の移動を伴う放電現象である。従来、回路端部の形状を回避する方法が提案されているが、本発明者らは、回路基板に使用する窒化けい素基板の表面とろう材の密着性に注目し鋭意検討をおこなった。 The partial discharge, which is the subject of the present invention, applies a voltage between the circuit surface and the heat radiating surface of the circuit board, and the portion where the electric field tends to concentrate in the metal circuit to which the voltage is applied, for example, the shape of the end has an acute angle. This is a discharge phenomenon in which an electric field concentration occurs at a small portion or a portion where the curvature is locally small, and the charge amount is irregularly or continuously transferred to a portion having a low electric field density of 10 pC or more. Conventionally, a method for avoiding the shape of the circuit end has been proposed, but the present inventors have conducted intensive studies focusing on the adhesion between the surface of the silicon nitride substrate used for the circuit substrate and the brazing material.
以下に本発明に関する窒化けい素基板の製造方法について説明する。 A method for manufacturing a silicon nitride substrate according to the present invention will be described below.
窒化けい素の結晶は、塊状晶α型と柱状晶のβ型の2種類があるが、窒化けい素基板として適しているのは、基板の強度の高い柱状晶のβ型を主結晶としたものである。本発明者らは、基板表面の詳細な分析をおこなった結果、基板表面の開気孔は、２つのモードがあることを見出した。１つは、前記柱状晶が異常粒成長した結晶が重なりあう部分からなるものであり、もう１つは、微粉が凝集し形成されている部分からなるものである。すなわち、基板表面で結晶粒子の異常な粒成長であったり、微粉の凝集体であることから、いずれも原料粉に起因することが考えられた。そこて、本発明者らは、窒化けい素基板の原料粉は、最大粒径が１０μｍ以下でかつ体積累積１０％径が０．５μｍ以上である分級調整した原料粉を用いることが好ましいと考えた。すなわち、原料粉の最大粒径を１０μｍ以下とするのは、１０μｍを越える粗粉を除くことで基板表面での異常粒成長を防止するためであり、体積累積１０％径を０．５μｍ以上とするのは、原料粉の微粉を減らし、微粉凝集を防止するためである。 There are two types of silicon nitride crystals, the bulk crystal α-type and the columnar crystal β-type, but the silicon nitride substrate is suitable for the columnar crystal β-type with high substrate strength as the main crystal. Is. As a result of detailed analysis of the substrate surface, the present inventors have found that the open pores on the substrate surface have two modes. One is composed of a portion where the crystals in which the columnar crystals have grown abnormally overlap each other, and the other is composed of a portion where fine powders are aggregated and formed. In other words, it was considered that these were caused by the raw material powder because of abnormal grain growth of crystal grains on the substrate surface or aggregates of fine powder. Therefore, the present inventors consider that it is preferable to use a raw material powder whose classification is adjusted such that the maximum particle size is 10 μm or less and the 10% volume cumulative diameter is 0.5 μm or more as the raw material powder of the silicon nitride substrate. It was. That is, the reason why the maximum particle size of the raw material powder is 10 μm or less is to prevent abnormal grain growth on the substrate surface by removing coarse powder exceeding 10 μm, and the volume cumulative 10% diameter is 0.5 μm or more. The reason is to reduce the fine powder of the raw material powder and prevent the fine powder from agglomerating.
上記原料粉を焼結助剤と混合し、窒化けい素基板のグリーンシートに成形する手段としては、一般的に用いられる原料粉、焼結助剤、溶媒、バインダー等の混合・分散させたスラリーを成形するドクターブレード法やキャスティング法等を用いることは可能である。しかしながら、急激に溶媒を揮発させると微細な開気孔がシート表面に発生したり、シートに乾燥クラックを生じる恐れがあるため、成形手段としては、溶媒量をできるだけ抑えて混合し、粘土状の混練物を形成する押出成形法が好ましく、さらには、防爆設備が不要で厚み調整が容易であり、品質の安定した製造をおこなうことができる水系押出成形法がより好ましい。 As a means for mixing the raw material powder with a sintering aid and forming it into a green sheet of a silicon nitride substrate, a slurry in which generally used raw material powder, a sintering aid, a solvent, a binder, etc. are mixed and dispersed. It is possible to use a doctor blade method, a casting method, or the like. However, if the solvent is suddenly volatilized, fine open pores may be generated on the surface of the sheet or dry cracks may occur in the sheet. An extrusion molding method for forming a product is preferable, and an aqueous extrusion molding method that does not require an explosion-proof facility, can be easily adjusted in thickness, and can be manufactured with stable quality is more preferable.
上記にて作成したグリーンシートは、離型剤をシートの表面に塗布した後、積層し、脱脂をおこなう。本発明に関わる基板の脱脂方法に関しては、溶媒やバインダー除去の急激な変動によって基板表面に開気孔の発生を防ぐために、１３．３Ｐａの真空中にて１２０℃で５時間維持した後、６００℃で２時間維持し、緩やかに脱脂をおこなうことが望ましい。すなわち、真空中で１２０℃に加熱するのは、揮発せずに残った溶媒を除去するためであり、雰囲気を真空中でおこなうのは、積層したシート内部の水分の残留や、シートに吸着した水分を除去するためである。次に、昇温速度２℃／分にて７００℃に昇温するまでにゆっくりと空気を導入し、大気圧に戻した後、脱脂時の残炭を軽減するために、炉内圧がわずかに陽圧となるよう１０Ｌ／分の空気を炉内に導入し、脱脂炉内を空気フロー状態にして７００℃、３時間を維持する。このとき、昇温しながら空気を導入するのは、分子量の大きなバインダー成分の脱脂を促し、シート内部や表面が急激な脱脂の影響を防ぐためである。また、炉内圧を大気圧よりわずかに陽圧とするのは、炉内に残留する脱脂時に発生する炭素を含むガスを炉外に排出するためである。 The green sheet prepared above is laminated and degreased after a release agent is applied to the surface of the sheet. Regarding the substrate degreasing method according to the present invention, in order to prevent the generation of open pores on the substrate surface due to abrupt changes in solvent and binder removal, after maintaining at 120 ° C. for 5 hours in a vacuum of 13.3 Pa, 600 ° C. It is desirable to keep it for 2 hours and gently degrease. That is, heating to 120 ° C. in vacuum is for removing the solvent that remains without volatilization, and the atmosphere in vacuum is for moisture remaining inside the stacked sheets or adsorbed to the sheets. This is for removing moisture. Next, air is slowly introduced until the temperature is raised to 700 ° C. at a rate of temperature rise of 2 ° C./minute, and after returning to atmospheric pressure, the furnace pressure is slightly reduced to reduce residual coal during degreasing. Air of 10 L / min is introduced into the furnace so as to be positive pressure, and the inside of the degreasing furnace is brought into an air flow state and maintained at 700 ° C. for 3 hours. At this time, the air is introduced while raising the temperature in order to promote degreasing of the binder component having a large molecular weight and to prevent the effect of the rapid degreasing on the inside and the surface of the sheet. The reason why the pressure in the furnace is slightly positive from the atmospheric pressure is to discharge the gas containing carbon generated during degreasing remaining in the furnace to the outside of the furnace.
脱脂を経た成形体は、脱脂炉から取り出し、焼成炉に移し替えて焼成をおこなうが、本発明に関わる窒化けい素基板の焼成は、脱脂後の吸着水の影響を軽減するために、まず、１３．３Ｐａの真空下で７００℃までの昇温をおこなう。その後、窒素を導入し、０．８〜０．９ＭＰａに加圧するまで７００℃を維持し、加圧後、１８００〜１９００℃の焼成温度まで昇温し、０．５〜５．０時間維持する。このとき、窒素を加圧状態で炉内に封入するのは、焼結助剤の揮発を防ぎ、基板表面の細孔を軽減させるためであり、さらに焼成時間を５．０時間以下にするのは、焼結助剤の揮発をできるだけ低減させるためである。そのため、本発明に関わる窒化けい素基板の焼成後の冷却は、７００℃以下になるまで加圧状態を維持することが肝要である。焼成した窒化けい素基板は、ジェットスクライブなどの湿式処理にて表面の離型剤を除去することによって得られる。 The degreased molded body is taken out from the degreasing furnace, transferred to the firing furnace and fired, but the firing of the silicon nitride substrate according to the present invention is first performed in order to reduce the influence of adsorbed water after degreasing, The temperature is raised to 700 ° C. under a vacuum of 13.3 Pa. Thereafter, nitrogen is introduced and maintained at 700 ° C. until pressurized to 0.8 to 0.9 MPa. After pressurization, the temperature is raised to a firing temperature of 1800 to 1900 ° C. and maintained for 0.5 to 5.0 hours. . At this time, nitrogen is sealed in the furnace in a pressurized state in order to prevent volatilization of the sintering aid and to reduce pores on the substrate surface, and to further reduce the firing time to 5.0 hours or less. Is to reduce the volatilization of the sintering aid as much as possible. Therefore, it is important that the cooling after firing the silicon nitride substrate according to the present invention is maintained in a pressurized state until 700 ° C. or lower. The fired silicon nitride substrate is obtained by removing the surface release agent by a wet process such as jet scribing.
ここで、本発明者らは、上記製造方法によって得られた基板について、表面粗さ計で計測し従来の基板と比較したが、いずれもＲａは０．３μｍ前後であり、有意差がみられなかった。そのため本発明者らは、基板表面の開気孔に注目し、開気孔容積を定量測定できる水銀圧入法を用いて基板表面の直径１μｍ以上１００μｍ未満の細孔積算容積を計測したところ、従来の基板が０．１０ｃｍ３／ｇ前後であるに対し、本発明に関わる基板は０．０５ｃｍ３／ｇ以下となっており、上記に記述した製造方法によって基板表面の開気孔を低減できることを確認できた。 Here, the inventors measured the substrate obtained by the above manufacturing method with a surface roughness meter and compared it with a conventional substrate, and in all cases, Ra is around 0.3 μm, showing a significant difference. There wasn't. Therefore, the present inventors have focused on the open pores on the substrate surface and measured the pore integrated volume with a diameter of 1 μm or more and less than 100 μm on the substrate surface using a mercury intrusion method capable of quantitatively measuring the open pore volume. Is about 0.10 cm 3 / g, whereas the substrate according to the present invention is 0.05 cm 3 / g or less, and it was confirmed that open pores on the substrate surface can be reduced by the manufacturing method described above. .
本特許に関する回路基板の達成すべき課題は電気特性の向上である。一般的に回路基板の電界強度は、基板の厚みが厚くなると低下するため、絶縁破壊電圧や部分放電開始電圧は高くなる。そのため、回路基板の電気特性を比較するには、基板の厚みの影響を考慮した比較が必要であり、また、回路基板を使用したモジュールにおいては、絶縁破壊電圧を目安として設計されていることを鑑み、回路基板の部分放電開始電圧が絶縁破壊電圧の８５％以上であることを具体的な達成すべき目標とした。 The problem to be achieved by the circuit board relating to this patent is the improvement of electrical characteristics. In general, the electric field strength of a circuit board decreases as the thickness of the board increases, so that the breakdown voltage and the partial discharge start voltage increase. Therefore, in order to compare the electrical characteristics of circuit boards, it is necessary to make a comparison that takes into account the influence of the thickness of the board. Also, modules that use circuit boards must be designed with dielectric breakdown voltage as a guide. In view of this, a specific target to be achieved is that the partial discharge start voltage of the circuit board is 85% or more of the dielectric breakdown voltage.
従来の基板及び、既に記述した本発明に関する基板を使用し、表裏ベタパターン（基板端部から回路端部の最短距離：２．０ｍｍ、基板端部から放熱板端部の最短距離：０．８ｍｍ）である回路基板を作成し、部分放電開始電圧と絶縁破壊電圧を計測したところ、従来の基板を使用した回路基板の部分放電開始電圧は、絶縁破壊電圧の７０〜７５％前後であるのに対し、本発明に関する基板を回路基板とした場合、８５〜８９％であり、部分放電開始電圧の向上が確認された。 Using a conventional substrate and a substrate related to the present invention described above, a front and back solid pattern (shortest distance from the substrate edge to the circuit edge: 2.0 mm, shortest distance from the substrate edge to the heat sink edge: 0.8 mm) ) And the partial discharge start voltage and the breakdown voltage were measured. The partial discharge start voltage of the circuit board using the conventional substrate was about 70 to 75% of the breakdown voltage. On the other hand, when the circuit board according to the present invention was used as a circuit board, it was 85 to 89%, and an improvement in the partial discharge start voltage was confirmed.
これらの回路基板を断面観察によって両者の差異を確認したところ、金属回路−窒化けい素基板間にあるろう材層界面に差が見られ、低い電圧で部分放電を発生する回路基板には、部分的に空隙が生じているのに対し、良好な回路基板には空隙は観察されなかった。このことから、課題である部分放電特性を向上させるためには、金属回路−窒化けい素基板間の空隙をなくすことが有効であり、本発明に関する基板を用いて回路基板とすることで電気特性を向上でき、課題を解決できる有効な手段であることがわかった。 When the difference between the two was confirmed by cross-sectional observation of these circuit boards, there was a difference in the brazing filler metal layer interface between the metal circuit and the silicon nitride substrate, and there was a partial On the other hand, no voids were observed on a good circuit board, whereas voids were generated. Therefore, in order to improve the partial discharge characteristics, which is a problem, it is effective to eliminate the gap between the metal circuit and the silicon nitride substrate, and the electrical characteristics can be obtained by using the substrate related to the present invention as a circuit substrate. It was found that this is an effective means for improving the problem and solving the problem.
次に本発明に関する回路基板の製造方法について説明する。 Next, a method for manufacturing a circuit board according to the present invention will be described.
本発明で用いられる金属回路、金属放熱板と窒化けい素基板との接合は、ろう材層を介して行われる。このろう材層は、Ａｇ、Ｃｕ又はＡｇ−Ｃｕ合金とＴｉ、Ｚｒ、Ｈｆ等の活性金属成分とを含むろう材を用いる活性金属ろう付け法によって形成することができる。さらに詳細に説明すると、ろう材層の形成方法は、例えば、Ａｇ、Ｃｕ及び例えばＴｉ、Ｚｒ、Ｈｆ等の活性金属を含む合金箔を用いたり、これらの単体金属かこれらの複数を合金化した微粉を、例えばポリイソブタンメタクリレート等のバインダー及びテルピネオール等の分散溶剤と混合してペーストを調製し、例えばスクリーン印刷法、ロールコーター法等によって、セラミックス基板の表面及び裏面に塗布することで施し、窒化けい素基板の表面に金属回路形成用金属板を、裏面に放熱板形成用金属板を配置し、真空中または非酸化性雰囲気下の炉内にて加熱し、ろう材層を形成することができる。 The metal circuit and metal heat sink used in the present invention are joined to the silicon nitride substrate through a brazing material layer. This brazing material layer can be formed by an active metal brazing method using a brazing material containing Ag, Cu or an Ag—Cu alloy and an active metal component such as Ti, Zr, and Hf. More specifically, the brazing material layer is formed by using, for example, an alloy foil containing Ag, Cu and an active metal such as Ti, Zr, or Hf, or alloying these single metals or a plurality of these. A fine powder is mixed with a binder such as polyisobutane methacrylate and a dispersion solvent such as terpineol to prepare a paste. For example, the paste is applied to the front and back surfaces of the ceramic substrate by a screen printing method, a roll coater method, etc. A metal circuit forming metal plate is placed on the surface of the silicon substrate, and a heat sink forming metal plate is placed on the back surface, and heated in a furnace in a vacuum or non-oxidizing atmosphere to form a brazing material layer. it can.
本発明に関わる回路基板の製造方法は、窒化けい素基板に金属回路形成用、金属放熱板形成用の金属板を活性金属ろう付け法にて接合体を製造した後、所望の回路形状及び放熱板形状をエッチングによって形成する。このとき、本発明における回路基板は、従来提案された手法の組み合わせることにより、さらに部分放電特性を向上することができる。
例えば回路端部から基板端部までの最短距離と放熱板端部と基板端部までの最短距離の差を０〜０．３ｍｍとすることで電界集中の緩和により電気特性が向上するが、その際、基板端部から回路端部の最短距離は、０．８ｍｍ以上とすることが好ましい。上記回路基板とした場合、部分放電開始電圧を絶縁破壊電圧の９０％以上とすることが可能となる。
上記基板端部から回路端部の最短距離が０．８ｍｍ未満である場合、特に３ｋＶ以上の高電圧で使用する場合では、表裏間の絶縁距離が短く、沿面放電による部分放電の発生頻度が高くなるために回路基板の絶縁特性を維持できない場合がある。
The method for manufacturing a circuit board according to the present invention is to manufacture a joined body of a metal plate for forming a metal circuit and a metal heat dissipation plate on a silicon nitride substrate by an active metal brazing method, and then a desired circuit shape and heat dissipation. A plate shape is formed by etching. At this time, the partial discharge characteristics of the circuit board according to the present invention can be further improved by combining conventional techniques.
For example, by setting the difference between the shortest distance from the circuit edge to the board edge and the shortest distance from the heat sink edge to the board edge to be 0 to 0.3 mm, the electrical characteristics are improved by relaxing the electric field concentration. At this time, the shortest distance from the substrate end to the circuit end is preferably 0.8 mm or more. When the circuit board is used, the partial discharge start voltage can be 90% or more of the dielectric breakdown voltage.
When the shortest distance from the substrate edge to the circuit edge is less than 0.8 mm, especially when used at a high voltage of 3 kV or more, the insulation distance between the front and back is short, and the frequency of occurrence of partial discharge due to creeping discharge is high. Therefore, the insulation characteristics of the circuit board may not be maintained.
以上の工程を経ることにより、本発明に関する回路基板は製造されるが、回路基板は必要に応じて、膜厚が１〜８μｍ程度の無電解Ｎｉめっきが施される。Ｎｉめっきを施さないときは、研削、物理研磨、化学研磨等によって金属表面をＲａ≦０．８μｍに平滑化した後、防錆剤が塗布される。また、ロットトレースを目的として、インクジェットやレーザーマーカー等の装置を用いて、バーコードや二次元コードなど、印字若しくは刻印等を基板毎に施される。 The circuit board according to the present invention is manufactured through the above steps, but the circuit board is subjected to electroless Ni plating with a film thickness of about 1 to 8 μm as necessary. When Ni plating is not applied, the metal surface is smoothed to Ra ≦ 0.8 μm by grinding, physical polishing, chemical polishing, or the like, and then a rust inhibitor is applied. For the purpose of lot tracing, printing or marking such as a bar code or a two-dimensional code is performed for each substrate using an apparatus such as an ink jet or a laser marker.
［実施例１〜６］
予め、風力分級機（日清エンジニアリング社製ターボクラッシファイア、型式ＴＣ−１５Ｎ）にて粗粉及び微粉を除いた窒化けい素粉末１００質量部に対して、有機バインダー１０質量部、並びに、焼結助剤の総使用量８．５質量部（Ｙ２Ｏ３：７質量部、ＭｇＯ：１．５質量部）を窒化けい素製ポット及びボールを入れたボールミル混合機に入れ、窒素置換／封入後、２時間混合した。
その後、混合粉末のみポットから取り出し、取り出した混合粉末をミキサー撹拌しながら、混合粉末１００質量部に対して可塑剤３質量部、イオン交換水１８質量部の混合溶液を噴霧し、顆粒状の湿粉原料を作製した。
〈使用原料〉
・窒化けい素粉末：電気化学工業社製、商品名「デンカ窒化けい素」 グレード名「ＮＰ−６００」（α化率８８％、酸素量０．９質量％）。
・Ｙ２Ｏ３：信越化学工業社製、商品名「Yttrium Oxide」、Ｄ５０径１．０μｍ
・ＭｇＯ：岩谷化学社製、商品名「ＭＴＫ−３０」、Ｄ５０粉末粒子径０．２μm
・有機バインダー：ヒドロキシプロピルメチルセルロース。信越化学工業社製、商品名「メトローズ６５SH」
・可塑剤：花王社製、商品名「エキセパール」、主成分グリセリン
[Examples 1 to 6]
In advance, 10 parts by mass of organic binder and 100 parts by mass of organic binder with respect to 100 parts by mass of silicon nitride powder excluding coarse powder and fine powder by a wind classifier (turbo classifier manufactured by Nisshin Engineering, Model TC-15N) Put 8.5 parts by mass of auxiliary agent (Y 2 O 3 : 7 parts by mass, MgO: 1.5 parts by mass) into a ball mill mixer containing a silicon nitride pot and balls, and replace with nitrogen. After that, it was mixed for 2 hours.
Thereafter, only the mixed powder is taken out from the pot, and while the mixed powder taken out is stirred by a mixer, a mixed solution of 3 parts by mass of a plasticizer and 18 parts by mass of ion-exchanged water is sprayed on 100 parts by mass of the mixed powder, and granular wet A powder raw material was prepared.
<Raw materials>
Silicon nitride powder: manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “Denka Silicon Nitride” Grade name “NP-600” (alpha conversion: 88%, oxygen content: 0.9 mass%).
Y 2 O 3 : manufactured by Shin-Etsu Chemical Co., Ltd., trade name “Yttrium Oxide”, D50 diameter 1.0 μm
MgO: Iwatani Chemicals, trade name “MTK-30”, D50 powder particle size 0.2 μm
Organic binder: hydroxypropyl methylcellulose. Product name "Metrouse 65SH", manufactured by Shin-Etsu Chemical Co., Ltd.
・ Plasticizer: manufactured by Kao Corporation, trade name “EXCEPARL”, main component glycerin
次に混練機（神戸製鋼社製ＨＹＰＥＲＫＴＸ３０）に湿粉原料を投入し、混練し、得られた練土を真空押出成形機(宮崎鉄工社製ＦＭ３０)にてシート形状に成型し、１００℃に保持したベルト式乾燥機にてシートの含水率が２質量％となるまで乾燥した後、所望の寸法にて打ち抜き、シートの表裏に離型剤をスプレー塗布した。その後、窒化ほう素製の容器に積層／充填し、真空脱脂炉にて、真空中１３．３Ｐａ下、１２０℃で５時間保持し、６００℃まで昇温／２時間保持した。その後、２℃／分で７００℃まで昇温するまでにゆっくりと空気を導入し、大気圧に戻した後、１０Ｌ／分の空気を導入し、炉内圧が大気圧よりわずかに陽圧となるように排気孔の開度を調整し、７００℃で３時間保持した。脱脂後大気中で放冷し、加圧カーボンヒーター電気炉に窒化ほう素容器を移し、１３．３Ｐａの真空下にて７００℃まで昇温したのち、０．９MPaの窒素加圧雰囲気下となるまで温度を保持する。その後、１８５０℃まで昇温し、３時間保持した後、７００℃以下となるまで加圧雰囲気を保持した。放冷後、基板を容器から取り出し、ジェットスクライブにて表面の離型剤を除去し、窒化けい素基板を得た。 Next, the wet powder raw material is put into a kneading machine (HYPERKTX30 manufactured by Kobe Steel Co., Ltd.) and kneaded. After drying the sheet with a held belt dryer until the moisture content of the sheet became 2% by mass, the sheet was punched out to a desired size and sprayed with a release agent on the front and back of the sheet. Then, it laminated | stacked / filled the container made from boron nitride, and it hold | maintained at 120 degreeC under vacuum of 13.3Pa for 5 hours in a vacuum degreasing furnace, and heated up and hold | maintained to 600 degreeC for 2 hours. Thereafter, air is slowly introduced until the temperature is raised to 700 ° C. at 2 ° C./minute, and after returning to atmospheric pressure, 10 L / minute of air is introduced, and the furnace pressure becomes slightly positive from atmospheric pressure. Thus, the opening degree of the exhaust hole was adjusted and held at 700 ° C. for 3 hours. After degreasing, it is allowed to cool in the atmosphere, and the boron nitride container is transferred to a pressurized carbon heater electric furnace. After raising the temperature to 700 ° C. under a vacuum of 13.3 Pa, a nitrogen pressurized atmosphere of 0.9 MPa is obtained. Hold the temperature up to. Then, after heating up to 1850 degreeC and hold | maintaining for 3 hours, the pressurized atmosphere was hold | maintained until it became 700 degrees C or less. After standing to cool, the substrate was taken out of the container, and the surface release agent was removed by jet scribing to obtain a silicon nitride substrate.
焼成した窒化けい素基板に一部は、表面粗さ測定(Ra)、水銀圧入法にて細孔分布の測定をおこなった結果を表１に示す。
〈測定方法〉
・表面粗さ測定：JIS B0601−1994に準ずる測定（ミツトヨ製・型式SJ-301・測定長0.8mm）
・細孔分布の測定：水銀ポロシメーター（島津製作所製・型式オートポア４−９５００・水銀圧入法)使用
Table 1 shows the results of measuring the pore distribution by a surface roughness measurement (Ra) and mercury intrusion method for a part of the fired silicon nitride substrate.
<Measuring method>
・ Surface roughness measurement: Measurement according to JIS B0601-1994 (Mitutoyo ・ Model SJ-301 ・ Measurement length 0.8mm)
・ Measurement of pore distribution: Mercury porosimeter (manufactured by Shimadzu, model autopore 4-9500, mercury intrusion method) used
〈窒化けい素回路基板の作製〉
回路基板としての性能を評価するため、金属回路と金属放熱板に銅板を用い、次の方法で接合及び回路パターンの形成を行った。
<Production of silicon nitride circuit board>
In order to evaluate the performance as a circuit board, a copper plate was used for the metal circuit and the metal heat sink, and bonding and circuit pattern formation were performed by the following method.
Ag８５質量％、Cu１０質量％、Zr２質量％、TiH３質量％からなる混合粉末１００質量部に対して、テレピネオール１５質量部、ポリイソブチルメタクリレート１．３質量部を添加し、三本ロールを用いて混合した後、目開き４０μｍのナイロンメッシュを通過させ、ろう材ペーストを調整した。作製したペーストは、基板の両面に乾燥基準で塗布量６mg／ｃｍ２となるようにロールコーター印刷機にて塗布した。次に、両面に基板と同じサイズの無酸素銅板を配置した２０組を積層した後、カーボン治具にカーボンネジ締めに設置し、真空雰囲気下（６．５×１０−４Ｐａ）、８２０℃で４５分保持させて、窒化けい素基板と銅板の接合体を作製した。接合体の一主面には表１に示す所定の形状の回路パターンを、もう一方の主面には放熱板パターンを形成させるべく、UV硬化型レジストインクをスクリーン印刷した後、UVランプを照射させてレジスト膜を硬化させた。次いで、レジスト塗布した部分以外を塩化第二銅溶液でエッチングし、次いでフッ化アンモニウム水溶液にてろう材層を除去した後、レジスト膜を剥離し、化学研磨によりＲａ０．８μｍ以下に銅表面を調整した後に、無電解ニッケルめっき厚み３μｍを施し、窒化けい素回路基板を作製した。作製した回路基板を用いて部分放電開始電圧及び絶縁破壊電圧を計測し、部分放電開始電圧を絶縁破壊電圧の相対値とした結果を表１に示す。 15 parts by mass of terpineol and 1.3 parts by mass of polyisobutyl methacrylate are added to 100 parts by mass of mixed powder composed of 85% by mass of Ag, 10% by mass of Cu, 2% by mass of Zr, and 3% by mass of TiH, and mixed using three rolls. After that, a brazing material paste was prepared by passing through a nylon mesh having an opening of 40 μm. The prepared paste was applied on both sides of the substrate with a roll coater printer so that the application amount was 6 mg / cm 2 on a dry basis. Next, after stacking 20 sets of oxygen-free copper plates of the same size as the substrate on both sides, they were placed on a carbon jig with carbon screws tightened, and under a vacuum atmosphere (6.5 × 10 −4 Pa), 820 ° C. For 45 minutes to produce a bonded body of silicon nitride substrate and copper plate. In order to form a circuit pattern of the prescribed shape shown in Table 1 on one main surface of the joined body and a heat sink pattern on the other main surface, UV-curable resist ink is screen-printed and then irradiated with a UV lamp. The resist film was cured. Next, the portion other than the resist-coated portion is etched with a cupric chloride solution, and then the brazing material layer is removed with an aqueous ammonium fluoride solution. Then, the resist film is peeled off and the copper surface is adjusted to Ra 0.8 μm or less by chemical polishing. After that, an electroless nickel plating thickness of 3 μm was applied to produce a silicon nitride circuit board. Table 1 shows the results of measuring the partial discharge start voltage and the breakdown voltage using the fabricated circuit board and setting the partial discharge start voltage as a relative value of the breakdown voltage.
〈使用材料〉
・無酸素銅板：住友金属鉱山伸銅株式会社製無酸素銅板（JIS H 3100）
・UV硬化型レジストインク：互応化学工業株式会社製「PER−２７B−６」
〈測定方法〉
・部分放電開始電圧及び絶縁破壊電圧の測定：作製した回路基板を絶縁油（住友３Ｍ社製「フロリナートＦＣ−４０」）に浸漬して、１ｋＶ／分のスピードで電圧を印可したとき、部分放電電荷量が１０ｐＣを超した時の電圧を部分放電開始電圧とし、その後さらに昇圧し、絶縁破壊する電圧の測定をおこなった。測定した部分放電開始電圧は、絶縁破壊電圧に対する相対値を算出した（n=５平均値）。
<Materials used>
・ Oxygen-free copper plate: Oxygen-free copper plate (JIS H 3100) manufactured by Sumitomo Metal Mining Copper Co., Ltd.
UV curable resist ink: “PER-27B-6” manufactured by Kyoyo Chemical Industry Co., Ltd.
<Measuring method>
・ Measurement of partial discharge start voltage and breakdown voltage: Partial discharge when voltage was applied at a speed of 1 kV / min by immersing the fabricated circuit board in insulating oil ("Fluorinert FC-40" manufactured by Sumitomo 3M) The voltage at which the charge amount exceeded 10 pC was used as the partial discharge start voltage, and then the voltage was further increased to measure the voltage at which dielectric breakdown occurred. The measured partial discharge start voltage was calculated as a relative value to the dielectric breakdown voltage (n = 5 average value).
［比較例１〜３］
窒化けい素基板を従来の基板に変更したこと以外は同一処理にてサンプルを作成した。
[Comparative Examples 1-3]
A sample was prepared by the same process except that the silicon nitride substrate was changed to a conventional substrate.
評価結果を表１に示す。 The evaluation results are shown in Table 1.
上記表１に示す結果から明らかなように窒化けい素基板が水銀圧入法による基板表面の直径１μｍ以上１００μｍ未満の細孔積算容積が０．０５ｃｍ３／ｇ以下（０を含まず）であると部分放電開始電圧が絶縁破壊電圧の８５％以上に向上できること、さらに上記基板を用い、回路端部から窒化けい素基板端部までの最短距離が０．８ｍｍ以上であり、回路端部から基板端部までの最短距離と放熱板端部から窒化けい素基板端部までの最短距離の差が０〜０．３ｍｍとすることにより部分放電開始電圧が絶縁破壊電圧の９０％以上とできることが確認できた。上記結果から、本発明に関わる窒化けい素回路基板を具備するモジュールにおいては、部分放電開始電圧を大幅に向上することができる。 As is clear from the results shown in Table 1 above, when the silicon nitride substrate has a pore integrated volume of 0.05 to less than 100 μm in diameter of the substrate surface by mercury intrusion method is 0.05 cm 3 / g or less (excluding 0). The partial discharge starting voltage can be improved to 85% or more of the dielectric breakdown voltage, and the shortest distance from the circuit end to the silicon nitride substrate end is 0.8 mm or more using the substrate, and the circuit end to the substrate end It can be confirmed that the partial discharge start voltage can be 90% or more of the dielectric breakdown voltage when the difference between the shortest distance to the heat sink and the shortest distance from the end of the heat sink to the end of the silicon nitride substrate is 0 to 0.3 mm. It was. From the above results, in the module having the silicon nitride circuit board according to the present invention, the partial discharge start voltage can be greatly improved.
本発明の窒化けい素回路基板は、半導体を搭載する部材として使用され、具体的には、例えば電鉄、電気自動車、一般産業用のインバータ用モジュール等に用いられる。 The silicon nitride circuit board of the present invention is used as a member for mounting a semiconductor. Specifically, it is used for, for example, electric railways, electric vehicles, inverter modules for general industries, and the like.
１ 窒化ケイ素基板
２ 金属回路
３ 金属放熱板
ｈ１ 回路端部から窒化けい素基板端部までの距離
ｈ２ 放熱板端部から窒化けい素基板端部までの距離
DESCRIPTION OF SYMBOLS 1 Silicon nitride substrate 2 Metal circuit 3 Metal heat sink h1 Distance from circuit end to silicon nitride substrate end h2 Distance from heat sink end to silicon nitride substrate end
Claims (3)
A module comprising the silicon nitride circuit board according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2012045202A JP2013182983A (en) | 2012-03-01 | 2012-03-01 | Silicon nitride circuit board and module using the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2012045202A JP2013182983A (en) | 2012-03-01 | 2012-03-01 | Silicon nitride circuit board and module using the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2013182983A true JP2013182983A (en) | 2013-09-12 |
Family
ID=49273443
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2012045202A Pending JP2013182983A (en) | 2012-03-01 | 2012-03-01 | Silicon nitride circuit board and module using the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2013182983A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022004755A1 (en) * | 2020-06-30 | 2022-01-06 | 株式会社トクヤマ | Silicon nitride sintered substrate |
| JP2024503523A (en) * | 2021-01-20 | 2024-01-25 | 中国科学院上海硅酸塩研究所 | Manufacturing method for high thermal conductivity/net size silicon nitride ceramic substrate |
| JP2024503494A (en) * | 2021-01-20 | 2024-01-25 | 中国科学院上海硅酸塩研究所 | Method for producing silicon nitride ceramic materials |
| JPWO2024062832A1 (en) * | 2022-09-20 | 2024-03-28 |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000349400A (en) * | 1999-06-04 | 2000-12-15 | Denki Kagaku Kogyo Kk | Circuit board |
| WO2007018050A1 (en) * | 2005-08-11 | 2007-02-15 | Denki Kagaku Kogyo Kabushiki Kaisha | Silicon nitride substrate, silicon nitride circuit substrate using the same, and its use |
-
2012
- 2012-03-01 JP JP2012045202A patent/JP2013182983A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000349400A (en) * | 1999-06-04 | 2000-12-15 | Denki Kagaku Kogyo Kk | Circuit board |
| WO2007018050A1 (en) * | 2005-08-11 | 2007-02-15 | Denki Kagaku Kogyo Kabushiki Kaisha | Silicon nitride substrate, silicon nitride circuit substrate using the same, and its use |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022004755A1 (en) * | 2020-06-30 | 2022-01-06 | 株式会社トクヤマ | Silicon nitride sintered substrate |
| JPWO2022004755A1 (en) * | 2020-06-30 | 2022-01-06 | ||
| CN115702130A (en) * | 2020-06-30 | 2023-02-14 | 株式会社德山 | Silicon nitride sintered substrate |
| JP7693675B2 (en) | 2020-06-30 | 2025-06-17 | 株式会社トクヤマ | Silicon nitride sintered substrate |
| EP4174020A4 (en) * | 2020-06-30 | 2025-07-02 | Tokuyama Corp | SINTERED SILICON NITRIDE SUBSTRATE |
| JP2024503523A (en) * | 2021-01-20 | 2024-01-25 | 中国科学院上海硅酸塩研究所 | Manufacturing method for high thermal conductivity/net size silicon nitride ceramic substrate |
| JP2024503494A (en) * | 2021-01-20 | 2024-01-25 | 中国科学院上海硅酸塩研究所 | Method for producing silicon nitride ceramic materials |
| JP7578835B2 (en) | 2021-01-20 | 2024-11-06 | 中国科学院上海硅酸塩研究所 | Method for preparing silicon nitride ceramic material |
| JP7641046B2 (en) | 2021-01-20 | 2025-03-06 | 中国科学院上海硅酸塩研究所 | Manufacturing method for high thermal conductivity net-sized silicon nitride ceramic substrate |
| JPWO2024062832A1 (en) * | 2022-09-20 | 2024-03-28 | ||
| WO2024062832A1 (en) * | 2022-09-20 | 2024-03-28 | 株式会社 東芝 | Ceramic substrate, ceramic circuit substrate, and semiconductor device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5339214B2 (en) | Method for manufacturing silicon nitride substrate and silicon nitride substrate | |
| JP5673847B2 (en) | Silicon nitride substrate and method for manufacturing silicon nitride substrate | |
| CN106537580B (en) | Ceramic circuit board and method for manufacturing the same | |
| CN112912356B (en) | Method for manufacturing silicon nitride substrate and silicon nitride substrate | |
| JP5042829B2 (en) | Manufacturing method of ceramic sheet | |
| JP2013182983A (en) | Silicon nitride circuit board and module using the same | |
| JP5142198B2 (en) | Silicon nitride substrate, silicon nitride circuit substrate using the same, and use thereof | |
| CN114929650A (en) | Circuit board, joined body, and method for manufacturing the same | |
| JP6565527B2 (en) | Power module substrate and power module with Ag underlayer | |
| WO2016052392A1 (en) | SUBSTRATE FOR POWER MODULE WITH Ag UNDERLAYER AND POWER MODULE | |
| JP2023050453A (en) | Ceramic substrate, ceramic circuit board, and method of manufacturing ceramic substrate | |
| JP6008259B2 (en) | Method for producing nitride ceramics | |
| WO2024190346A1 (en) | Aluminum nitride sintered body, and method for manufacturing aluminum nitride sintered body | |
| JP7064065B1 (en) | How to improve the electrical insulation of ceramic sintered bodies, substrates, and ceramic sintered bodies | |
| WO2023038151A1 (en) | Method for producing boron nitride sintered body, and boron nitride sintered body | |
| JP2007189112A (en) | Silicon nitride substrate and circuit board and module using the same. | |
| JP2001019555A (en) | Silicon nitride sintered body and circuit board using the same | |
| JP4347206B2 (en) | Manufacturing method of ceramic sheet, ceramic substrate using the same, and use thereof | |
| JP7322323B1 (en) | Boron nitride sintered body and composite | |
| JP7576209B2 (en) | Silicon nitride sintered body, its manufacturing method, bonded body, and power module | |
| JP2010159184A (en) | Method for producing aluminum nitride sintered compact | |
| WO2024111484A1 (en) | Bonded body and power module | |
| JP4520243B2 (en) | Manufacturing method of ceramic sheet, ceramic substrate using the same, and use thereof | |
| WO2025094690A1 (en) | Aluminum nitride sintered body, method for producing same, and circuit board | |
| JP4987345B2 (en) | Aluminum nitride substrate |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20150123 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20150827 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20150901 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20151102 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20160223 |