JP2016082224A - Heat dissipation substrate and module for semiconductor using the same - Google Patents
Heat dissipation substrate and module for semiconductor using the same Download PDFInfo
- Publication number
- JP2016082224A JP2016082224A JP2015172325A JP2015172325A JP2016082224A JP 2016082224 A JP2016082224 A JP 2016082224A JP 2015172325 A JP2015172325 A JP 2015172325A JP 2015172325 A JP2015172325 A JP 2015172325A JP 2016082224 A JP2016082224 A JP 2016082224A
- Authority
- JP
- Japan
- Prior art keywords
- metal
- heat dissipation
- composite material
- metal layer
- dissipation 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
Abstract
Description
本発明は高性能な半導体モジュールのパッケージ(以下PKGと略記)に搭載するものであって、表面に欠陥の少ない金属層を有し、半導体モジュールに適した線膨張係数と、大きな熱伝導率を有する安価な金属ダイヤモンド系の放熱基板に関する。 The present invention is mounted on a package of a high performance semiconductor module (hereinafter abbreviated as PKG), has a metal layer with few defects on the surface, and has a linear expansion coefficient suitable for the semiconductor module and a large thermal conductivity. The present invention relates to an inexpensive metal diamond-based heat dissipation substrate.
半導体モジュールには、LSI、IGBT、パワー半導体、電波・光通信用半導体、レーザー、LED、センサー等の用途があり、これらに必要な性能によって構造も多種多様である。半導体モジュールは異なる線膨張係数と熱伝導率の材料からなる部材で構成された、非常に高度な精密機器であり、そのPKGに使用される放熱基板も多様な複合材や形状のものが多く提案されている。 Semiconductor modules have applications such as LSIs, IGBTs, power semiconductors, semiconductors for radio waves and optical communications, lasers, LEDs, sensors, etc., and the structures vary depending on the performance required for these. The semiconductor module is a highly sophisticated precision instrument composed of materials made of materials with different linear expansion coefficients and thermal conductivities, and the heat dissipation board used in the PKG has many proposals for various composite materials and shapes. Has been.
半導体モジュールの放熱基板には、PKGの製作、半導体デバイスのハンダ付けにおいて、性能や寿命を確保するために、適した線膨張係数が必要である。熱伝導率についても、半導体デバイスの熱を放散して冷却し性能や寿命を確保するために、高い値が必要である。他に各種部材や半導体デバイスを接合するために、良好なメッキを施し易いことも極めて重要である。 The heat dissipation substrate of a semiconductor module must have a suitable coefficient of linear expansion in order to ensure performance and longevity in the manufacture of PKG and soldering of semiconductor devices. Also for the thermal conductivity, a high value is required to dissipate and cool the heat of the semiconductor device to ensure performance and life. In addition, in order to join various members and semiconductor devices, it is also very important that good plating is easily performed.
また放熱基板の形状を大別すると、厚み1mm以下で数ミリ角のサブマウント、平板、ネジ止め平板、三次元形状等があり、これらの形状が得やすい製法が望まれる。 In addition, the shape of the heat dissipation board can be broadly classified into sub-mounts, flat plates, screwed flat plates, three-dimensional shapes, etc. with a thickness of 1 mm or less and several millimeters square, and a production method that can easily obtain these shapes is desired.
放熱基板には、当初はCuが用いられていたが、近年の半導体モジュールの高性能化で発熱量が大きくなり、これまでのCuでは線膨張係数が大きすぎるためにPKGの製造工程と耐久性、さらに半導体デバイスの性能寿命での問題が発生した。このため、高性能半導体モジュールに対応した線膨張係数を有する放熱基板が求められるようになった。 Initially, Cu was used for the heat dissipation board, but the heat generation amount has increased with the recent high performance of semiconductor modules, and since the coefficient of linear expansion is too large with conventional Cu, the manufacturing process and durability of PKG In addition, problems with the performance life of semiconductor devices occurred. For this reason, the heat dissipation board which has a linear expansion coefficient corresponding to a high performance semiconductor module came to be calculated | required.
この対策として線膨張係数を変更・調整することができ、高性能半導体モジュールの線膨張係数に対応できるCuW、CuMo（特許文献１）が開発された。また軽量化が必要な場合の対応としてAlSiC（特許文献２）が開発された。しかし、これらのいずれの複合材も半導体モジュールに適した線膨張係数での熱伝導率が320W/m・K以下の値でCuより小さいという問題点があった。 As countermeasures, CuW and CuMo (Patent Document 1) that can change and adjust the linear expansion coefficient and can cope with the linear expansion coefficient of a high-performance semiconductor module have been developed. Moreover, AlSiC (patent document 2) was developed as a response | compatibility when weight reduction is required. However, any of these composite materials has a problem that the thermal conductivity at a linear expansion coefficient suitable for the semiconductor module is 320 W / m · K or less and smaller than Cu.
このためCuW、CuMo、AlSiCがカバーする範囲の6.5ppm/K以上15ppm/K以下の線膨張係数を有し、熱伝導率がCuの393W/m・Kと同じか、それ以上で金属の中で最も熱伝導率が高いAgの420W/m・K以上の材質が望まれ、種々の放熱基板の複合材料が研究開発されてきた。 For this reason, it has a linear expansion coefficient of 6.5 ppm / K or more and 15 ppm / K or less in the range covered by CuW, CuMo, and AlSiC, and the thermal conductivity is the same as or higher than that of Cu at 393 W / m · K. A material with an Ag of 420 W / m · K or higher, which has the highest thermal conductivity, is desired, and various heat sink substrate composite materials have been researched and developed.
放熱基板には線膨張係数と熱伝導率の特性以外にメッキの品質が重要である。半導体モジュールメーカーで半導体デバイスや絶縁板をハンダ付で接合する際に、接合界面にボイドが多く存在すると熱の流れが遮断され、半導体デバイスや絶縁板に剥離や破壊が起こる。このため良好なハンダ付が可能な最終のNi系メッキを施し得る欠陥の少ない表層を有する放熱基板が必要となる。 In addition to the characteristics of linear expansion coefficient and thermal conductivity, the quality of plating is important for the heat dissipation board. When a semiconductor module manufacturer joins a semiconductor device or an insulating plate with solder, if there are many voids at the bonding interface, the heat flow is interrupted, and the semiconductor device or the insulating plate is peeled off or broken. For this reason, a heat dissipation substrate having a surface layer with few defects that can be subjected to final Ni-based plating capable of good soldering is required.
最終のNi系メッキには、品質確保のための種々の形態があり、これらの形態に対応するため、放熱基板メーカーでメッキを行う場合とPKGメーカーでメッキを行う場合があり、品質に対応するために多様なNi系メッキ、ハンダ材質、ハンダ付の条件等の開発が行われてきた。これらの開発において最終のNi系メッキの品質確保には、放熱基板の表層に欠陥の少ないことが極めて重要であり、それを実現するため種々の放熱基板の開発が進められてきた。 The final Ni-based plating has various forms to ensure quality. In order to correspond to these forms, there is a case where plating is performed by a heat sink substrate manufacturer and a case where plating is performed by a PKG manufacturer. Therefore, various Ni-based plating, solder materials, soldering conditions, etc. have been developed. In these developments, in order to ensure the quality of the final Ni-based plating, it is extremely important that the surface layer of the heat dissipation substrate has few defects, and various heat dissipation substrates have been developed to realize this.
最終のNi系メッキには種々の形態があるため、一般的には最終のNi系メッキを施す前の線膨張係数と熱伝導率の値が複合材の放熱基板の基準特性として使用されている。 Since there are various forms of final Ni-based plating, generally the values of linear expansion coefficient and thermal conductivity before final Ni-based plating are used as the reference characteristics of the heat dissipation substrate of the composite material .
Cuの放熱基板は、表層の欠陥が少ないので、良好な最終のNi系メッキを施すことが容易である。しかしCuWやCuMoの機械加工品や研磨品は相対密度が低いと表層欠陥の問題が発生し易いので、実用化には相対密度が真密度の99%以上が必要であるとされている。しかしCuMo系のクラッド品においては表層がCu層なので最終のNiメッキを施す上での問題は回避できている。 Since the heat dissipation substrate of Cu has few surface layer defects, it is easy to apply a good final Ni-based plating. However, CuW and CuMo machined products and polished products are prone to surface defect problems when the relative density is low, and it is said that the relative density must be 99% or more of the true density for practical use. However, in CuMo-based clad products, since the surface layer is a Cu layer, problems in applying the final Ni plating can be avoided.
AlSiCでは相対密度が真密度の99%以上であってもセラミックのSiCにメッキがし難いという問題がある。しかし複合材にピンホールなどの欠陥やメッキがし難いSiCがあっても、複合材の製作時にその表層に純Al箔や溶浸金属のAlの層を設けることにより、最終のNi系メッキを良好に施すことができている。 AlSiC has a problem that it is difficult to plate ceramic SiC even if the relative density is 99% or more of the true density. However, even if the composite material has defects such as pinholes or SiC that is difficult to plate, the final Ni-based plating can be achieved by providing a pure Al foil or an infiltrated metal Al layer on the surface of the composite material. It can be applied satisfactorily.
近年、半導体モジュールの急速な発展と高性能化で半導体デバイスの発熱が大きくなってきており、それに伴って熱対策が重要になってきている。このため半導体モジュールの線膨張係数に対応できる線膨張係数を有し、かつ熱伝導率が高く、ハンダ濡れ性の評価より厳しい接合界面におけるボイド評価に合格する良好なハンダ付ができる新しい高品質な放熱基板が強く望まれていた。 In recent years, due to the rapid development and higher performance of semiconductor modules, the heat generation of semiconductor devices has increased, and accordingly, countermeasures against heat have become important. For this reason, it has a linear expansion coefficient that can correspond to the linear expansion coefficient of the semiconductor module, has high thermal conductivity, and can be soldered well to pass void evaluation at the joint interface more severe than solder wettability evaluation. A heat dissipation substrate was strongly desired.
高性能半導体モジュールの放熱基板として、金属ダイヤモンドの放熱基板が高い熱伝導率が得られる可能性があり有望であることから、これまで様々な研究開発が行われ、報告されている。 As a heat dissipation substrate for high-performance semiconductor modules, a metal diamond heat dissipation substrate is promising because there is a possibility that high thermal conductivity can be obtained, and various research and development have been conducted and reported so far.
金属とダイヤモンドのみの場合には、金属のダイヤモンドへの濡れ性があまりにも悪く、既存のCuWやCuMoの製造法で採用されている溶浸法や焼結法では放熱基板に使用できる複合材は製造が困難であった。こうしたなか、Cuとダイヤモンドの粉末をキャニングし、高温で5万気圧の高圧下で焼結する超高圧焼結法（特許文献３）で高い熱伝導率が得られるとの報告がある。しかしこの製法では相対密度が高い複合材が得られるものの、ダイヤモンドが多い組成範囲のため、線膨脹係数が小さ過ぎるうえに、製造コストも高くなる。また製品形状の製作加工には、ブロック素材のスライス加工や研削加工が必要で、それに起因する欠陥により最終のNi系メッキの品質に問題が生じ、用途が限定されていた。 In the case of only metal and diamond, the wettability of metal to diamond is too bad, and composite materials that can be used for heat dissipation substrates by the infiltration and sintering methods used in the existing CuW and CuMo manufacturing methods are not available. Manufacturing was difficult. Under these circumstances, it has been reported that a high thermal conductivity can be obtained by an ultra-high pressure sintering method (Patent Document 3) in which Cu and diamond powders are canned and sintered at a high temperature of 50,000 atm. However, although this manufacturing method can provide a composite material having a high relative density, the composition range with a large amount of diamond causes the linear expansion coefficient to be too small and the manufacturing cost to be high. In addition, the manufacturing process of the product shape requires slicing and grinding of the block material, and defects resulting from it cause problems in the quality of the final Ni-based plating, limiting the application.
主金属と添加金属とダイヤモンドの粉末を混合した圧粉体を焼結することでダイヤモンド表面に添加金属の炭化物ができ、高い熱伝導率が得られるとの報告（特許文献４）がある。しかし、この製法の複合材は不安定で高い真密度が得られないため、表面に多数のピンホールがあり良好な最終のNi系メッキの品質が確保できないという問題点がある。このため放熱基板として使用できる複合材の放熱基板は得られていなかった。 There is a report (Patent Document 4) that, by sintering a green compact in which a main metal, an additive metal, and a diamond powder are mixed, a carbide of the additive metal is formed on the diamond surface and high thermal conductivity is obtained. However, since the composite material of this manufacturing method is unstable and high true density cannot be obtained, there is a problem in that a large number of pinholes are present on the surface, and satisfactory final Ni-based plating quality cannot be ensured. For this reason, a composite heat dissipation substrate that can be used as a heat dissipation substrate has not been obtained.
ダイヤモンド粉末の表層に添加金属の炭化物の膜を形成したスケルトンに金属を溶浸する製造法を用いて高い熱伝導率が得られるとの報告（特許文献５）がある。この製法は焼結法に比べ高い真密度と熱伝導率が得られるが、スケルトンの構造が不安定なため組成にバラツキが生じるという問題がある。また外周の余剰な溶浸金属をダイヤモンド砥石で研削除去する必要が生じ、それによって複合材の表面のダイヤモンドの欠けや脱粒、特にダイヤモンドと金属の界面剥離等が生じて、金属の蒸着を施したとしても放熱基板に必要な品質を有する最終のNi系メッキが施せないという問題点がある。そのため放熱基板として使用できる複合材とはならなかった。 There is a report (Patent Document 5) that a high thermal conductivity can be obtained by using a manufacturing method in which a metal is infiltrated into a skeleton in which a carbide film of an additive metal is formed on the surface layer of diamond powder. Although this manufacturing method can obtain a higher true density and thermal conductivity than the sintering method, there is a problem that the composition of the skeleton varies due to the unstable structure of the skeleton. In addition, it was necessary to grind and remove the excess infiltrated metal on the outer periphery with a diamond grindstone, which caused diamond chipping or degranulation on the surface of the composite material, particularly interfacial delamination between diamond and metal, and metal deposition was performed. However, there is a problem that the final Ni plating having the quality required for the heat dissipation substrate cannot be applied. Therefore, the composite material could not be used as a heat dissipation substrate.
ダイヤモンド粉末にCuメッキした粉末の圧粉体をSPS(Spark Plasma Sintering：放電プラズマ焼結)法で焼結して高い熱伝導率が得られるとの報告（特許文献６）がある。しかし、ダイヤモンド粉末へのCuメッキは費用が高く、加えてSPS通電焼結法で高い熱伝導率を得るには、長時間の焼結が必要で生産性が低いという問題点がある。また表層にダイヤモンドが露出することがあり、良好なハンダ付ができる最終のNi系メッキの品質が確保できない問題点があった。 There is a report (Patent Document 6) that high thermal conductivity can be obtained by sintering a green compact of a powder obtained by Cu plating on diamond powder by an SPS (Spark Plasma Sintering) method. However, Cu plating on diamond powder is expensive, and in addition, in order to obtain high thermal conductivity by the SPS current sintering method, there is a problem that long-time sintering is required and productivity is low. Further, there is a problem that diamond may be exposed on the surface layer, and the quality of the final Ni-based plating capable of good soldering cannot be ensured.
ダイヤモンド粉末にSiCのセラミックコートを施したスケルトンにAl・Si・Mg合金を加圧溶浸（特許文献７）することで、高熱伝導率でありながら表層に溶浸金属の膜を形成した結果、最終のNi系メッキの品質も満足できるという報告がある。しかし、薄い放熱基板の場合には、表層に熱伝導率の小さい溶浸金属の層があるため放熱基板に適さない。また、精密な治具を用いて表層に溶浸金属の層を設けるには製造難度が高く、安価に複合材ができないので経済的でない。加えて表層の溶浸金属の膜は、必ずしも最終のNi系メッキに適しているとはいえない。更にこの製法はAl合金にしか適用できず、スケルトンの安定性を確保するには組成範囲もAl合金が60%以下と限定される。このため放熱基板として使用できる範囲に限界があり用途が限定されていた。 As a result of forming an infiltrated metal film on the surface layer with high thermal conductivity by pressure infiltrating Al / Si / Mg alloy into a skeleton with SiC ceramic coating on diamond powder (Patent Document 7), There are reports that the quality of the final Ni plating is satisfactory. However, a thin heat dissipation board is not suitable for a heat dissipation board because the surface layer has an infiltrated metal layer having a low thermal conductivity. Further, it is not economical to provide an infiltrated metal layer on the surface layer using a precise jig because the manufacturing difficulty is high and a composite material cannot be produced at low cost. In addition, the surface infiltrated metal film is not necessarily suitable for the final Ni-based plating. Furthermore, this production method can be applied only to Al alloys, and the composition range is limited to 60% or less for Al alloys in order to ensure the stability of the skeleton. For this reason, the range which can be used as a heat dissipation board has a limit, and the use was limited.
ダイヤモンド粉末に金属やセラミックのコーテイングを施した圧粉体にCuを溶浸した複合材に、純Cu板を銀ろう付してPKG（特許文献８）を製造した報告がある。しかし、ダイヤモンド粉末に金属やセラミックのコーテイングを施す費用は高く、加えて外周の余剰な溶浸金属をダイヤモンド砥石で研削除去する必要があり、その後にCu板を銀ろう付するので、製造工程が多く経済的でない。また金属ダイヤモンドの放熱基板に純Cu板を銀ろう付すると、Cuと銀ろう材が反応して合金となり熱伝導率の小さい層が生成する。またCu板が厚くてもろう付部にボイド等の欠陥が生じる問題点がある。このため放熱基板として使用できる複合材は未だ商品化されていない。 There is a report of manufacturing PKG (Patent Document 8) by silver brazing a pure Cu plate to a composite material in which Cu is infiltrated into a green compact obtained by applying metal or ceramic coating to diamond powder. However, the cost of applying metal or ceramic coating to diamond powder is high, and in addition, it is necessary to grind and remove excess infiltrated metal on the outer periphery with a diamond grindstone. Not much economic. In addition, when a pure Cu plate is silver brazed to a metal diamond heat dissipation substrate, Cu and the silver brazing material react to form an alloy to form a layer having a low thermal conductivity. Moreover, even if the Cu plate is thick, there is a problem that defects such as voids occur in the brazed portion. For this reason, the composite material which can be used as a heat dissipation board has not been commercialized yet.
これまでに報告された金属ダイヤモンド系の複合材の放熱基板において、金属とダイヤモンドの比率を変えることで線膨張係数の可変・調整ができ、ダイヤモンドの比率を増やすことや大きな粒子のダイヤモンドを使用することにより、CuやAgを超える大きな熱伝導率が有する放熱基板を得られることが報告されている。 In the heat dissipation board of metal diamond based composite materials reported so far, the coefficient of linear expansion can be changed and adjusted by changing the ratio of metal to diamond, increasing the ratio of diamond and using large particles of diamond Thus, it has been reported that a heat dissipation substrate having a large thermal conductivity exceeding Cu and Ag can be obtained.
しかし、金属ダイヤモンド系の放熱基板において真密度が99%以上の複合材料であっても、表層にダイヤモンドが露出してメッキが付かないために、露出したダイヤモンドと同程度の大きさのメッキホールの欠陥が生じる。このため最終のNi系メッキにメッキホールの欠陥が転写され、表層に現われるという問題がある。またダイヤモンド砥石で研削した後、Ti等の金属の蒸着を行うことでダイヤモンドがメッキに覆われてメッキホールの欠陥は無くなるものの、ダイヤモンドと金属の界面剥離による影響により、新たにメッキの金属層の表層に数μm以下のピンホールが生じ、これに起因して良好なハンダ付ができる最終のNi系メッキの品質が確保できないという問題がある。 However, even if it is a composite material with a true density of 99% or more in a metal diamond-based heat dissipation substrate, since the diamond is exposed on the surface layer and plating does not occur, a plating hole of the same size as the exposed diamond Defects occur. For this reason, there is a problem that defects in the plating hole are transferred to the final Ni-based plating and appear on the surface layer. In addition, after grinding with a diamond grindstone, the deposition of a metal such as Ti will cover the diamond with plating and eliminate defects in the plating hole. There is a problem that pinholes of several μm or less are generated on the surface layer, and this makes it impossible to ensure the quality of the final Ni-based plating capable of good soldering.
一方、主金属と添加金属およびダイヤモンドからなる液相焼結の複合材では、露出したダイヤモンドの表面が添加金属の炭化物と金属からなる層に覆われるので、メッキホール欠陥は生じない。しかし、Cu等に比べ添加金属の炭化物は、メッキがしにくく密着性が低いので、内部にボイドが生じ易く、また表層にも数μm以下のピンホールが生じ易いという問題がある。併せて焼結性が悪いため、複合材の相対密度が低くなり易く、また表層にも巣が生じ易く、これらが原因となってメッキの金属層にピンホール欠陥ができ、最終のNi系メッキの品質が確保できないという問題があった。 On the other hand, in a liquid phase sintered composite material composed of a main metal, an additive metal and diamond, the exposed diamond surface is covered with a layer made of carbide and metal of the additive metal, so that no plating hole defect occurs. However, since the carbide of the additive metal is hard to be plated and has low adhesion compared to Cu or the like, there is a problem that voids are easily generated inside and pinholes of several μm or less are also easily formed on the surface layer. In addition, since the sinterability is poor, the relative density of the composite material tends to be low, and the surface layer tends to form nests, which can cause pinhole defects in the plated metal layer, resulting in the final Ni-based plating. There was a problem that the quality of the could not be ensured.
こうした問題を解決するために、本発明の放熱基板は、主成分が金属とダイヤモンドからなる種々の製法で作られた複合材の表面にメッキで金属層を形成し、その金属層に加熱し加圧する固相焼結を行うことにより、表層に欠陥の少ない金属層を有し、半導体モジュールに適した線膨張係数と、高い熱伝導率を有した金属ダイヤモンド系の複合材からなる放熱基板を得るものである。 In order to solve such problems, the heat dissipation substrate of the present invention forms a metal layer by plating on the surface of a composite material made by various production methods consisting mainly of metal and diamond, and heats and adds the metal layer to the surface. By performing solid-phase sintering, a heat dissipation substrate made of a metal diamond-based composite material having a metal layer with few defects on the surface layer and having a linear expansion coefficient suitable for a semiconductor module and high thermal conductivity is obtained. Is.
なかでも主金属・添加金属・ダイヤモンドからなる粉末を混合し、その混合粉末の型押し後に液相焼結を行い得られた複合材に金属層をメッキで形成したのち、更に加熱し加圧する固相焼結を行うことにより、表層に欠陥の少ない金属層を有し、線膨張係数が6.5〜15ppm/Kの範囲にあり、熱伝導率が420W/m・K以上の半導体モジュール用の複合材からなる放熱基板を得るものである。 In particular, a powder composed of a main metal, additive metal, and diamond is mixed, a metal layer is formed by plating on the composite material obtained by liquid phase sintering after stamping of the mixed powder, and then heated and pressurized. By conducting phase sintering, a composite material for semiconductor modules having a metal layer with few defects on the surface layer, a linear expansion coefficient in the range of 6.5 to 15 ppm / K, and a thermal conductivity of 420 W / m · K or more To obtain a heat dissipation substrate.
粉末冶金の焼結法は高精度で多様な製品を最も低コストで製造できる方法であり、小型・中型品をニアネットシェイプで製造できる可能性が高く、この技術で種々の半導体部品が開発され実用化されている。 The powder metallurgy sintering method is the most accurate method for manufacturing various products at the lowest cost, and it is highly possible that small and medium-sized products can be manufactured in near net shape. With this technology, various semiconductor components have been developed. It has been put into practical use.
しかし、金属とダイヤモンドのみを液相焼結すると、ダイヤモンドに対する金属の濡れ性があまりにも悪く、焼結時に金属とダイヤモンドが分離するか表層に金属が粒状に生成してしまい、正常な複合材が得られない問題がある。 However, when only metal and diamond are liquid phase sintered, the wettability of the metal with diamond is too bad, and the metal and diamond are separated during the sintering or the metal is formed in a granular form on the surface layer. There is a problem that cannot be obtained.
一方、主金属・添加金属・ダイヤモンドの混合粉末の型押体を液相焼結した複合材は、相対密度が低くて不安定な問題があるが、露出したダイヤモンドの表面に添加金属の炭化物と主金属からなる層があるので、メッキで金属層を形成しても大きな欠陥が生じないことがある。しかし、添加金属の炭化物と主金属は必ずしもメッキし易くないという問題がある。併せて焼結性が悪いため複合材の表層に巣も生じ易い。これらが原因となって最終のNi系メッキの品質が確保できないという問題がある。更に金属層のメッキは厚みが大きくなると密着性が低下し、内部にボイド等が多く発生する。また表層の粒子が大きいと、凹凸を生じて脱落することもある。 On the other hand, a composite material obtained by liquid phase sintering of a mixed powder of main metal, additive metal, and diamond mixed powder has a low relative density and has an unstable problem. Since there is a layer made of the main metal, even if the metal layer is formed by plating, a large defect may not occur. However, there is a problem that the carbide of the added metal and the main metal are not always easily plated. In addition, since the sinterability is poor, nests are likely to occur in the surface layer of the composite material. For these reasons, there is a problem that the quality of the final Ni-based plating cannot be ensured. Further, when the thickness of the metal layer is increased, the adhesiveness is lowered, and many voids are generated inside. Moreover, when the surface layer particles are large, irregularities may be formed and fall off.
こうしたなか、主金属・添加金属・ダイヤモンドの液相焼結した複合材であっても良好なハンダ付ができる最終のNi系メッキを行う方法として、複合材にメッキで金属層を形成したものを加熱し加圧する固相焼結をすることで、金属層の密着性が向上し、また金属層の内部ボイド、ピンホール、ザラツキ等の欠陥が修復でき、同時にその金属層を加熱し加圧することで複合材が緻密化され特性が向上し安定化する効果があることを見出した。 Under these circumstances, as a method of performing the final Ni-based plating that enables good soldering even for liquid phase sintered composite materials of main metal, additive metal, and diamond, a metal layer formed by plating on the composite material is used. Solid-phase sintering with heating and pressurization improves the adhesion of the metal layer, and can repair defects such as internal voids, pinholes, and roughness of the metal layer, and simultaneously heat and pressurize the metal layer. It was found that the composite material is densified and has improved and stabilized properties.
高性能モジュールの放熱基板の品質は、近年では放熱基板に最終のNi系メッキを行い半導体デバイスや絶縁板にハンダ付けされた状態のハンダボイド率で確認されるようになってきている。そこでハンダボイド率を測定することにより、表層に欠陥の少ない金属層を形成すれば、放熱基板で最終のNi系メッキ品質が確保でき、厳しい規格に合格する良好なハンダ付が可能になることを確認した。 In recent years, the quality of the heat dissipation board of the high performance module has been confirmed by the solder void ratio in the state where the final Ni plating is applied to the heat dissipation board and soldered to a semiconductor device or an insulating plate. Therefore, by measuring the solder void ratio, it is confirmed that if a metal layer with few defects is formed on the surface layer, the final Ni-based plating quality can be secured on the heat dissipation substrate, and good soldering that passes strict standards can be achieved. did.
本発明によれば、金属・ダイヤモンド・添加物の混合粉末の型押品を液相焼結法で製造した複合材にメッキにより金属層を形成した後、真空中等の酸化しにくい雰囲気中で金属層の液相出現温度以下において50MPa以上の圧力下で固相焼結を行うことにより、金属層の表面と内部を修正できて欠陥の少ない金属層が得られ、良好なハンダ付ができる最終のNi系メッキ品質を確保できる放熱基板とすることができる。併せて複合材の緻密化で相対密度や熱伝導率の向上を図ることができる。 According to the present invention, after forming a metal layer by plating on a composite material produced by liquid phase sintering of a mixed powder of metal / diamond / additive powder, a metal is formed in an atmosphere that is difficult to oxidize, such as in a vacuum. By performing solid-phase sintering under the pressure of 50 MPa or more below the liquid phase appearance temperature of the layer, the surface and inside of the metal layer can be corrected to obtain a metal layer with few defects, and the final soldering can be performed with good soldering. It is possible to make a heat dissipation substrate that can ensure Ni-based plating quality. In addition, the relative density and the thermal conductivity can be improved by densifying the composite material.
欠陥の少ない金属層が得られることで線膨張係数と熱伝導率の値を満たせば内部の複合材の相対密度が90%以下と著しく低くなければ放熱基板としては最終のNi系メッキ品質に特に大きな問題は起こらないことも確認できているので、放熱基板として使用が可能である。 If the relative density of the internal composite material is not as low as 90% or less if the linear expansion coefficient and thermal conductivity values are satisfied by obtaining a metal layer with few defects, the final Ni-based plating quality is particularly good as a heat dissipation board Since it has been confirmed that no major problems occur, it can be used as a heat dissipation board.
放熱基板に耐熱性が必要な場合には主金属をAgやCu、それらの合金にすれば良く、軽量化が必要な場合には主金属をAlやAl合金にすることで達成できる。このようにしてCuW、CuMo、AlSiCの放熱基板の線膨張係数の範囲をカバーでき、良好なハンダ付ができ、かつ高い熱伝導率の複合材を提供できる。 When heat resistance is required for the heat dissipation substrate, the main metal may be Ag, Cu, or an alloy thereof. When weight reduction is required, the main metal can be Al or an Al alloy. Thus, the range of the linear expansion coefficient of the heat dissipation substrate of CuW, CuMo, and AlSiC can be covered, good soldering can be performed, and a high thermal conductivity composite material can be provided.
本発明は放熱基板の形状についても、サブマウント(数ミリ角×厚み0.1〜1mm)、平板（10〜250mm角×厚み0.8〜5mm）ネジ止め平板（10〜250mm角×厚み0.8〜5mm）、平板、三次元形状（大きさ10〜50mm×厚み1〜5mm）等に対応できる製法である。 As for the shape of the heat dissipation substrate, the present invention also includes a submount (several millimeters square x thickness 0.1 to 1 mm), a flat plate (10 to 250 mm square x thickness 0.8 to 5 mm), a screwed flat plate (10 to 250 mm square x thickness 0.8 to 5 mm), It is a manufacturing method that can accommodate flat plates, three-dimensional shapes (size 10-50 mm x thickness 1-5 mm), and the like.
また、厚み精度が厳しい放熱基板では研削が必要であるが、他の金属ダイヤモンドの複合材料の放熱基板と同様にダイヤモンド砥石の研削により複合材の表面のダイヤモンドの欠けや脱粒、特にダイヤモンドと金属の界面剥離が起こり、金属の蒸着を施したとしても良好な最終のNi系メッキができない問題があるが、複合材にTi、Cr、Au、Pt等の金属を蒸着した後にメッキで金属層を形成してから加熱加圧の固相焼結をすることで良好な最終のNi系メッキを確保することができる。 Grinding is required for heat dissipation boards with strict thickness accuracy. However, as with other metal diamond composite heat dissipation boards, diamond grinding and grinding of the surface of the composite material, especially diamond and metal Interfacial peeling occurs, and even if metal deposition is performed, there is a problem that good final Ni-based plating cannot be performed, but after depositing metal such as Ti, Cr, Au, Pt etc. on the composite material, a metal layer is formed by plating Then, good final Ni-based plating can be ensured by solid-phase sintering under heat and pressure.
更に同一組成で高い機械強度や大きな熱伝導率が必要な場合には、液相焼結後の複合材を融点直下の高温で高い圧力で加圧後、メッキで金属層を形成し、その金属層を形成した複合材を固相焼結することで本発明の放熱基板が得られる。 Furthermore, when high mechanical strength and high thermal conductivity are required with the same composition, the composite material after liquid phase sintering is pressed under high pressure at a high temperature just below the melting point, and then a metal layer is formed by plating. The composite material in which the layers are formed is solid-phase sintered to obtain the heat dissipation substrate of the present invention.
次に、最終の固相焼結は真空、減圧、非酸化、還元、不活性ガス等の雰囲気中で行うことも可能であるが、装置が大型化し焼結に時間を要する。しかし、市販の抵抗溶接機を使い、水中で固相焼結を行うことで容易かつ安価に製造することができる。また、この製法はスライス、研削、切断等の加工が不要なため、大きなダイヤモンド粒子を使用した高熱伝導率でニアネットシェイプの放熱基板が得られる。 Next, final solid-phase sintering can be performed in an atmosphere of vacuum, reduced pressure, non-oxidation, reduction, inert gas, etc., but the apparatus becomes large and requires time for sintering. However, it can be manufactured easily and inexpensively by performing solid phase sintering in water using a commercially available resistance welder. In addition, since this manufacturing method does not require processing such as slicing, grinding, and cutting, a near-net-shaped heat dissipation substrate can be obtained with high thermal conductivity using large diamond particles.
本発明は既存の技術の応用で金属ダイヤモンド系の複合材に良好なハンダ付ができる欠陥の少ない金属層を簡単に設けることができる技術である。また水中で固相焼結する新しい技術で金属・添加物・ダイヤモンドの放熱基板をニアネットシェイプで製作できる技術である。更にメッキ後に固相焼結することで複合材の相対密度や熱伝導率の向上と安定も図れる。 The present invention is a technique that can easily provide a metal layer with few defects that can be satisfactorily soldered to a metal diamond-based composite material by applying an existing technique. In addition, this technology enables metal, additive, and diamond heat dissipation substrates to be manufactured in near-net shape using a new technology for solid-phase sintering in water. Further, solid phase sintering after plating can improve and stabilize the relative density and thermal conductivity of the composite material.
本発明はCuW、CuMo、AlSiC等では製造ができなかったニアネットシェイプでの金属・添加金属・ダイヤモンドの高性能な放熱基板の製作が可能である。 The present invention makes it possible to manufacture a high-performance heat dissipation substrate of metal, additive metal, and diamond in a near net shape that could not be manufactured by CuW, CuMo, AlSiC, or the like.
以上のように本発明は主金属・添加金属・ダイヤモンドの粉末を混合し型押し後に液相焼結を行い、その複合材に金属層を設けたのち、加熱し加圧する固相焼結を行う二段階焼結により、表層に欠陥の少ない金属層を有し、線膨張係数6.5ppm/K以下15ppm/K以上の範囲で、熱伝導率420W/m・K以上で低価格の新しい発想の半導体モジュールの放熱基板を得ることができる。 As described above, in the present invention, the main metal, additive metal, and diamond powder are mixed and subjected to liquid phase sintering after embossing. After the metal layer is provided on the composite material, solid phase sintering is performed by heating and pressing. Two-step sintering has a metal layer with few defects on the surface layer, a new concept semiconductor with a low coefficient of thermal conductivity of 420 W / m · K or more in the range of coefficient of linear expansion of 6.5 ppm / K or less and 15 ppm / K or more A module heat dissipation board can be obtained.
（組成）
既に主金属がAg、Cu、Alやこれらの合金であれば・添加金属・ダイヤモンドを最適に混合し型押し後に液相焼結を行うことで線膨張係数6.5ppm/K以上15ppm/K以下の範囲、熱伝導率420W/m・K以上の放熱基板にできるとの報告がある。しかし、添加金属を使用しても焼結が不安定で相対密度が低いため、最終のNi系メッキの品質が確保できない問題があり、熱伝導率のバラツキが大きく、熱伝導率が安定して420W/m・K以上にならない問題等があるため実用化に至っていない。
本発明はメッキにより金属層を形成したのち加熱し加圧する固相焼結を行うことで、表層に欠陥の少ない金属層を形成して熱伝導率の向上と安定を図ったものである。
耐熱性が必要な場合、主金属はAg、Cu、またはこれらの合金が望ましい。大型の放熱基板で軽量化が必要な場合はAlやAl合金が望ましい。
(composition)
If the main metal is already Ag, Cu, Al or an alloy of these, it is possible to mix the additive metal and diamond optimally and perform liquid phase sintering after stamping to achieve a linear expansion coefficient of 6.5 ppm / K to 15 ppm / K. There is a report that a heat dissipation substrate with a thermal conductivity of 420 W / m · K or more can be made. However, there is a problem that the quality of the final Ni-based plating cannot be ensured because the sintering is unstable and the relative density is low even if the additive metal is used, the thermal conductivity varies greatly, and the thermal conductivity is stable. It has not been put into practical use due to problems such as not exceeding 420 W / m · K.
In the present invention, after forming a metal layer by plating, solid phase sintering is performed by heating and pressurizing to form a metal layer with few defects on the surface layer to improve and stabilize the thermal conductivity.
When heat resistance is required, the main metal is preferably Ag, Cu, or an alloy thereof. Al or Al alloy is desirable when a large heat dissipation board needs to be lightened.
添加金属はダイヤモンドと炭化物をつくるかまたは主金属と合金にできる元素であれば特に指定しないがTi、Cr、Co、Mn、Ni、Fe、B、Y、Si、Mg、Zn等で複合材全体の1vol%以上15vol%以下であり、一種類以上でも効果があれば問題ない。1vol%未満でも15vol%を超えても熱伝導率が420W/m・K以上にはならない。
Ag、Cu、とこれらの合金の場合、添加金属は、例えばTi、Cr、Co、Mn、Ni、Fe、Bであり、その量は複合材全体の1vol%以上5vol%以下が望ましく、1vol%未満でも5vol%を超えても熱伝導度率が420W/m・K以上にはならない。AlやAl合金の場合、添加金属は、例えばSiであり、その量は複合材全体の5vol%以上15vol%以下の値が望ましく、5vol%未満でも15vol%を超えても熱伝導度率が420W/m・K以上にはならない。また1.0vol%Mgを添加することで後述の液相焼結が安定する効果がある。
The additive metal is not specified as long as it is an element that can form diamond and carbide or can be alloyed with the main metal, but Ti, Cr, Co, Mn, Ni, Fe, B, Y, Si, Mg, Zn, etc. 1 vol% or more and 15 vol% or less, and there is no problem if one or more types are effective. Even if it is less than 1 vol% or exceeds 15 vol%, the thermal conductivity does not exceed 420 W / m · K.
In the case of Ag, Cu, and alloys thereof, the additive metal is, for example, Ti, Cr, Co, Mn, Ni, Fe, B, the amount is preferably 1 vol% or more and 5 vol% or less of the entire composite material, 1vol% Even if it is less than 5 vol%, the thermal conductivity does not exceed 420 W / m · K. In the case of Al or Al alloy, the additive metal is, for example, Si, and the amount is desirably 5 vol% or more and 15 vol% or less of the entire composite material, and the thermal conductivity is 420 W even if it is less than 5 vol% or exceeds 15 vol%. No more than / m · K. Further, the addition of 1.0 vol% Mg has an effect of stabilizing liquid phase sintering described later.
ダイヤモンドは熱伝導率の値を確保するため95%以上が10μm以上1000μm以下の範囲であることが望ましい。10μm以下では熱伝導率が420W/m・K以上は得られない。1000μm以上では熱伝導度向上の効果が少ない上に切断等の加工性が著しく低下し、更に粉末価格が大幅に高くなる。また上記の範囲の大小粒子のダイヤモンドを混合しても、その量が95%以上なら問題ない。5%以内の10μm以下1000μm以上の大小のダイヤモンドが混入していても問題ない。
他にダイヤモンドが高価なためダイヤモンドの一部を安価で低線膨張係数のSiC、W、Moで置換しても特性を満たせば問題ない。
It is desirable that 95% or more of diamond is in the range of 10 μm or more and 1000 μm or less in order to ensure the value of thermal conductivity. Below 10 μm, thermal conductivity of 420 W / m · K or more cannot be obtained. If it is 1000 μm or more, the effect of improving the thermal conductivity is small, the workability such as cutting is remarkably lowered, and the powder price is significantly increased. Moreover, even if diamonds of large and small particles in the above range are mixed, there is no problem if the amount is 95% or more. There is no problem even if large and small diamonds of 10 μm or less and 1000 μm or more within 5% are mixed.
In addition, since diamond is expensive, there is no problem even if a part of the diamond is replaced with SiC, W, or Mo having low linear expansion coefficient, if the characteristics are satisfied.
（液相焼結）
型押し後の焼結は真空、減圧、加圧、非酸化、還元ガス、不活性ガス中で主金属の液相出現温度以上が必要である。液相焼結することでダイヤモンド粒子の表層に添加金属とダイヤモンドが反応して炭化物ができる。更に炭化物と添加金属と主金属が反応した合金層ができ金属・添加物・ダイヤモンドからなる複合材ができる。
(Liquid phase sintering)
Sintering after embossing requires a temperature higher than the liquid phase appearance temperature of the main metal in vacuum, reduced pressure, pressurization, non-oxidation, reducing gas, or inert gas. By liquid phase sintering, the added metal and diamond react with the surface layer of diamond particles to form carbide. Furthermore, an alloy layer in which carbide, additive metal, and main metal are reacted can be formed, and a composite material including metal, additive, and diamond can be formed.
（金属層）
金属層は液相焼結後の複合材やその研磨品にメッキを被覆して形成するものでAg、Cu、Ni、それらの合金等を使い、厚みが5μm以上200μm以下であれば、複合材の全面、上下、半導体デバイスを搭載する部分のみでも問題ない。やわらかくて熱伝導度率の大きいAgやCuの金属層が好適であり、Niまたはこれらの合金のメッキはAl系ダイヤモンドの大型で寸法の厚い放熱基板に有効である。また金属層はAg、Cu、Niまたはこれらの合金を多層にメッキしても問題ない。
金属層の厚みが5μm以下では加熱加圧しても放熱基板に必要な欠陥の少ない金属層を全体に設けられない。また200μm以上では金属層が非常に不安定になるとともにメッキ費用が高くなる。
(Metal layer)
The metal layer is formed by coating the composite material after liquid phase sintering or its polishing product with Ag, Cu, Ni, alloys thereof, etc. If the thickness is 5 μm or more and 200 μm or less, the composite material There is no problem even on the entire surface, top and bottom, and only the part where the semiconductor device is mounted. A metal layer of Ag or Cu that is soft and has a high thermal conductivity is suitable, and plating of Ni or an alloy thereof is effective for a large-sized and large heat dissipation substrate of Al-based diamond. Further, there is no problem even if the metal layer is plated with Ag, Cu, Ni or an alloy thereof in multiple layers.
When the thickness of the metal layer is 5 μm or less, the metal layer with few defects necessary for the heat dissipation substrate cannot be provided on the whole even when heated and pressurized. If it is 200 μm or more, the metal layer becomes very unstable and the plating cost becomes high.
（固相焼結）
メッキ後の固相焼結は真空、減圧、加圧、非酸化、不活性ガス、難燃性液体、不燃性液等の雰囲気で行うことができるが、水中法で通電焼結を行うことで形状をニアネットシェイプで製作が可能でコスト的にも有利である。温度は液相出現温度以下で加圧50MPa以上500MPa以下の条件で固相焼結を行うことにより、複合材の表面にメッキされた金属層の欠陥を修復し、更に複合材自体の熱伝導率の向上と安定化を図ることができる。その製造はホットプレス（以下HPと略記）、鍛造、通電焼結等により可能である。この固相焼結で金属とダイヤモンドからなる複合材の表にメッキしたAg、Cu、Niや、それらの合金の金属層を、Cuの放熱基板の表層のような欠陥の少ない状態にできる。
(Solid phase sintering)
Solid phase sintering after plating can be performed in an atmosphere such as vacuum, reduced pressure, pressure, non-oxidation, inert gas, flame retardant liquid, non-flammable liquid, etc. The shape can be manufactured with a near net shape, which is advantageous in terms of cost. The solid phase sintering is performed at a temperature below the liquidus appearance temperature and under a pressure of 50 MPa or more and 500 MPa or less, thereby repairing defects in the metal layer plated on the surface of the composite material, and further the thermal conductivity of the composite material itself. Can be improved and stabilized. Its manufacture is possible by hot pressing (hereinafter abbreviated as HP), forging, electric current sintering and the like. The metal layer of Ag, Cu, Ni, or an alloy thereof plated on the surface of the composite material made of metal and diamond by this solid-phase sintering can be made into a state with few defects like the surface layer of the Cu heat dissipation substrate.
固相焼結の方法としては薄いシートやウエハーではHPで多段の製造ができ、効果的である。またニアネットシェイプには通電焼結が好適である。更に温度や圧力を加えることで熱伝導度の向上安定化が図れる。Ag、Cu、Niやそれらの合金のメッキは高温では軟化するので、温度400℃以上から液相出現温度以下で圧力50MPa以上500MPa以下の焼結をすれば良い。温度は400℃以下では十分な修復ができない、また600℃以上になると治具や電極の間から大きなバリが出始め、治具の寿命が著しく低下してしまう。AlやAl合金では融点が低いので500℃以下が望ましい。
圧力は50MPa以上で、それ以下では金属層の十分な修正ができない、また500MPa以上では大型装置を用いなければ加圧できないので経済的でない、また一般的な治具や電極では破壊してしまうことがある。このため複合材と金属層に適した固相焼結の条件温度や圧力や治具や電極を選択することが重要である。
As a solid-phase sintering method, thin sheets and wafers can be manufactured in multiple stages using HP, which is effective. Also, current sintering is suitable for the near net shape. Furthermore, the thermal conductivity can be improved and stabilized by applying temperature and pressure. Since plating of Ag, Cu, Ni and their alloys softens at high temperatures, sintering may be performed at a temperature of 400 ° C. to a liquid phase appearance temperature and a pressure of 50 MPa to 500 MPa. If the temperature is 400 ° C. or lower, sufficient repair cannot be performed. If the temperature is 600 ° C. or higher, large burrs begin to appear between the jig and the electrode, and the life of the jig is significantly reduced. Since Al and Al alloys have a low melting point, 500 ° C. or lower is desirable.
If the pressure is 50MPa or more, the metal layer cannot be sufficiently corrected, and if it is 500MPa or more, it cannot be pressurized unless a large device is used. There is. For this reason, it is important to select a solid-state sintering condition temperature, pressure, jig and electrode suitable for the composite material and the metal layer.
真空やガス中等での固相焼結は装置が大型化し加熱し加圧するのに時間を要し、また自動化が難しい。水中の固相焼結でも同じように金属層のメッキ改善効果が得られることから、市販の抵抗溶接機を用いて複合材を水中において金属の電極で挟み込み、通電焼結をすることにより数十秒の短時間で固相焼結ができ、かつ自動化も可能である。安定させるには金属の電極で挟みこんだまま電流の入り切りの通電を繰り返すことで効果が向上する。形状的にも小型品やネジ止め平板や三次元形状品の放熱基板をニアネットシェイプで大量生産が可能である。また、この製法によればダイヤモンド砥石の研削や切断加工の必要がなく、粒径の大きいダイヤモンド粉末を使用できるので高熱伝率の放熱基板が得られる。 Solid-phase sintering in vacuum, gas, etc. is large in size and requires time to heat and pressurize, and is difficult to automate. Since the effect of improving the plating of the metal layer can be obtained in the same way by solid-phase sintering in water, several tens of minutes can be obtained by sandwiching the composite material with metal electrodes in water using a commercially available resistance welder and conducting current sintering. Solid-phase sintering is possible in a short time, and automation is also possible. In order to stabilize, the effect is improved by repeatedly turning on and off the current while being sandwiched between metal electrodes. In terms of shape, it is possible to mass-produce small-sized products, screwed flat plates, and three-dimensional shaped heat-dissipating boards with a near net shape. Further, according to this manufacturing method, there is no need to grind or cut the diamond grindstone, and diamond powder having a large particle size can be used, so that a heat dissipation substrate having a high thermal conductivity can be obtained.
尚、加熱し加圧する固相焼結で金属層の一部がバリになり金属層の厚みが薄くなる。更に表面の粗さ精度を向上させるためバフ研磨で表面を目標の粗さにするので、更に薄くなることがあるが、最終的には複合材の表面全体に金属層が2μm以上残っていれば問題はない。 In addition, a part of the metal layer becomes burrs by solid-phase sintering that is heated and pressurized, and the thickness of the metal layer is reduced. In order to improve the surface roughness accuracy, the surface is made to the target roughness by buffing, so it may become even thinner, but eventually if the metal layer remains over 2 μm over the entire surface of the composite material No problem.
（加工）
薄いシートやウエハーの複合材の表面粗さは治具や電極の面粗さが転写されるので製品の形状にウォ―タージェット、高出力レーザー、ワイヤカット等で切断して製品化する。しかし、さらに精度が必要な場合には、金属層を研磨紙やバフで研磨し所定の表面粗さに仕上げ、製品の形状にウォ―タージェット、高出力レーザー、ワイヤカット等で切断して製品化することも可能である。またニアネットシェイプで作られる複合材は形状加工が不要でありコスト的に有利である。
(processing)
The surface roughness of the thin sheet or wafer composite material is transferred to the surface roughness of the jig or electrode, so the product is cut into a product shape with a water jet, high-power laser, wire cut, etc. to produce a product. However, if further accuracy is required, the metal layer is polished with abrasive paper or buff to finish to the specified surface roughness, and the product shape is cut by water jet, high power laser, wire cut, etc. It is also possible to In addition, the composite material made of near net shape does not require shape processing and is advantageous in terms of cost.
（最終メッキ）
最終のメッキは放熱基板に各種の部材、絶縁板、半導体デバイス等を銀ろう付やハンダ付等で接合することを目的として行われるが、放熱基板に欠陥があると、その影響で最終のNi系メッキに欠陥が発生し、良好な銀ろう付やハンダ付ができない問題が発生する。Ni系メッキが多層になっても次々と欠陥が転写されていくので問題は解決しない。
(Final plating)
The final plating is performed for the purpose of joining various members, insulating plates, semiconductor devices, etc. to the heat dissipation board by silver brazing or soldering. A defect occurs in the system plating, and there is a problem that good silver brazing and soldering cannot be performed. Even if Ni-based plating becomes multi-layered, defects are transferred one after another, so the problem is not solved.
半導体モジュールにおいては、放熱基板への半導体デバイスのハンダ接合が最も重要であり非常に低いボイド率が求められる。近年、様々なハンダ材質や技術が開発されてきたがPbフリー化と高温対応のためにSnAgCu(融点；218℃)のハンダ材が主に使われ評価にも使われる。 In a semiconductor module, solder bonding of a semiconductor device to a heat dissipation board is most important, and a very low void ratio is required. In recent years, various solder materials and technologies have been developed, but SnAgCu (melting point: 218 ° C) solder material is mainly used for Pb-free and high temperature, and it is also used for evaluation.
これまでのCuでは、電解Ni、無電解Ni-P、無電解Ni-Bが行われてきた。またCuWやCuMo系の放熱基板の最終のメッキは、電解Ni+無電解Ni-Pと、無電解Ni-P+無電解Ni-B、無電解Cu+無電解Ni-Pが行われる。さらにAlSiCでは無電解Ni-P+無電解Ni-Bである。一般的には良好なハンダ性を確保するため、最終メッキを3μmのNi-Bとした場合のハンダ付のボイド品質の評価が行われる。 Up to now, Cu, electroless Ni, electroless Ni-P, and electroless Ni-B have been performed. The final plating of the CuW or CuMo-based heat dissipation substrate is performed by electrolytic Ni + electroless Ni-P, electroless Ni-P + electroless Ni-B, and electroless Cu + electroless Ni-P. Furthermore, AlSiC is electroless Ni-P + electroless Ni-B. In general, in order to ensure good solderability, the evaluation of the void quality with solder when the final plating is 3 μm Ni-B is performed.
発明は最終のNiのメッキをCuW、CuMo、AlSiCのように多層のメッキも可能であるが複合合金の金属層が第1層の役目をはたすので最終の表層のNi系メッキのみでも問題ない。またメッキ金属層がNi系メッキの電解Ni、無電解Ni-P、無電解Ni-Bの場合は最終のメッキ自体の省略が可能である。 In the invention, the final Ni plating can be multi-layered like CuW, CuMo, and AlSiC. However, since the metal layer of the composite alloy serves as the first layer, there is no problem with only the Ni-based plating of the final surface layer. If the plated metal layer is Ni-plated electrolytic Ni, electroless Ni-P, or electroless Ni-B, the final plating itself can be omitted.
これまでJIS Z3197（対応国際規格ISO94455）によるハンダ広がり80%以上の規格でハンダ品質の評価がされることがあったが、規格がゆるすぎて実態と合わないので、ボイド面積5%以下の規格が使用されるようになってきている。 Until now, solder quality has been evaluated with 80% or more of solder spread according to JIS Z3197 (corresponding international standard ISO94455), but the standard is too loose to match the actual situation, so the standard with a void area of 5% or less Are beginning to be used.
最終のメッキが3μmのNi-BでSnAgCu（218℃）ハンダの評価は非常に厳しく超音波測定でボイド率5%以下を合格すれば銀ろう付、他のハンダ付け、樹脂付等で問題が起こらない知見がある。 The final plating is 3μm Ni-B and SnAgCu (218 ℃) solder is evaluated very severely. If the void ratio is less than 5% by ultrasonic measurement, there is a problem with silver brazing, other soldering, with resin, etc. There is knowledge that does not happen.
〈放熱基板の評価〉
（線膨張係数の測定）
固相焼結後の25mm×25mm×2〜2.5mm試料からWEDMやパワーレーザーで10mm×5mm×厚み2〜2.5mm切り出し熱膨張係数計(セイコー電子工業社製)でRT（25℃）の線膨張係数の測定を行う。
<Evaluation of heat dissipation board>
(Measurement of linear expansion coefficient)
25mm x 25mm x 2 to 2.5mm after solid phase sintering 10mm x 5mm x 2 to 2.5mm in thickness with WEDM or power laser cut RT (25 ° C) line with thermal expansion coefficient meter (Seiko Denshi Kogyo Co., Ltd.) The expansion coefficient is measured.
（熱伝導の測定）
固相焼結後の25mm×25mm×2〜2.5mmの試料からWEDMやパワーレーザーでφ10mm×厚み2mm〜2.5mmを切り出しレーザーフラッシュ法の熱伝導度計(アルバック理工製 TC-7000)でRT（25℃）の熱伝導率の測定を行う。
(Measurement of heat conduction)
Cut out a 10mm x 2mm to 2.5mm thickness from a 25mm x 25mm x 2 to 2.5mm sample after solid-phase sintering with a WEDM or power laser, using a laser flash thermal conductivity meter (TC-7000 made by ULVAC-RIKO) with RT ( Measure the thermal conductivity at 25 ° C.
（金属層の密着テスト）
固相焼結後の25mm×25mm×2〜2.5mmの試料を大気中に450℃に30分保持し、外観を顕微鏡の10倍の倍率で目視観察し、金属層のメッキのフクレがない場合はOKであり、大小にかかわらずフクレが見つかった場合にはNGと判断した。
(Metal layer adhesion test)
When a solid-size sintered sample of 25 mm x 25 mm x 2 to 2.5 mm is held in air at 450 ° C for 30 minutes, and the appearance is visually observed at a magnification of 10 times that of a microscope, and there is no swelling of the metal layer plating Was OK, and it was judged as NG when a blister was found regardless of size.
（ハンダボイド品質の測定）
固相焼結後の25mm×25mmの複合合金をバリ取りしバフ研磨後に3μmNi-Bメッキした放熱基板に10mm×10mm×0.7mmのSiデバイスの金属電極付を高温SnAgCu(218℃)ハンダで接合し超音波でボイドの面積を調べ5%以下なら合格（OK）、以上を不合格（NG）とした。なお、この評価は非常に厳しいので測定でボイド率5%以下を合格すれば銀ろう付、他のハンダ付け、樹脂付等で問題が起こらない知見がある。
(Measurement of solder void quality)
Deburring 25mm x 25mm composite alloy after solid-phase sintering, buffing and bonding to 3μm Ni-B plated heat dissipation board with metal electrode of 10mm x 10mm x 0.7mm Si device with high temperature SnAgCu (218 ° C) solder Then, the area of the void was examined with ultrasonic waves, and if it was 5% or less, it passed (OK), and the above was rejected (NG). In addition, since this evaluation is very strict, if the void ratio is 5% or less in the measurement, there is knowledge that no problem occurs with silver brazing, other soldering, resin attaching, etc.
（実施例１；Ag−Ti−ダイヤモンドの放熱基板試料、試料No. 9）
69vol%Ag、1vol%Ti、30vol%・30μmダイヤモンドの粉末を混合し25mm×25mmの金型を使用し圧力500MPaでプレス型押し後に真空中・温度1100℃・60分で液相焼結を行い、その複合材に金属層5μmのAgメッキ後、HPで温度400℃、圧力50MPa、30分保持で固相焼結を行い、バリ取り後、フクレテストを行い、その後3μmNi・Bメッキを行い、ハンダ付のボイド品質の評価を行った。
結果を表１に示す。
(Example 1; heat dissipation substrate sample of Ag-Ti-diamond, sample No. 9)
Mixing 69 vol% Ag, 1 vol% Ti, 30 vol% and 30 μm diamond powder, using a 25 mm x 25 mm mold, pressing the mold at a pressure of 500 MPa, and then performing liquid phase sintering in vacuum at a temperature of 1100 ° C for 60 minutes After the Ag plating of the metal layer of 5μm on the composite material, solid phase sintering is performed with HP at a temperature of 400 ° C, pressure of 50MPa, holding for 30 minutes, deburring is performed, then a bulge test is performed, and then 3μm Ni · B plating is performed and soldering is performed. The attached void quality was evaluated.
The results are shown in Table 1.
（実施例２；Cu−Cr−ダイヤモンドの放熱基板試料、試料No. 15）
35vol%Ag、5vol%Cr、60vol%・100μmダイヤモンドの粉末を混合し25mm×25mmの金型を用いて圧力500MPaでプレス型押し後に水素中・温度1200℃・60分で液相焼結を行い、その複合材に金属層の50μmのCuメッキを施した後、セラミック治具に複合材を入れ通電焼結機で圧力300MPaがかかるように上下電極で加圧し、通電加熱で600℃、5分保持で固相焼結を行い、バリ取り後、フクレテストを行い、その後3μmNi・Bメッキを行い、ハンダ付のボイド品質の評価を行った。
結果を表１に示す。
(Example 2: Cu-Cr-diamond heat dissipation substrate sample, sample No. 15)
35vol% Ag, 5vol% Cr, 60vol%, 100μm diamond powder is mixed and pressed using a 25mm x 25mm die at a pressure of 500MPa and then liquid phase sintered in hydrogen at 1200 ℃ for 60 minutes. After applying 50μm Cu plating of the metal layer to the composite material, put the composite material in a ceramic jig and pressurize it with the upper and lower electrodes so that the pressure is 300MPa with an electric sintering machine, and heat at 600 ℃ for 5 minutes Solid-phase sintering was performed with deburring, burrs were removed, a blister test was performed, and then 3 μm Ni / B plating was performed to evaluate the quality of soldered voids.
The results are shown in Table 1.
（実施例３；Ag−Ti−ダイヤモンド−残Cuの放熱基板、試料No. 24）
10vol%Ag、37vol%Cu、3vol%Ti、30vol%・100μmと20vol%・30μmダイヤモンド粉末を混合し25mm×25mmの金型を用いて圧力500MPaでプレス型押し後に、真空1000℃で60分保持する液相焼結後、その複合材に金属層の100μmのCuメッキを施した後、その素材１を図１のセラミック治具４に入れ抵抗溶接機を用いて水中６で上下電極２、３により100MPa加圧しながら通電し温度500℃で2秒保持し、それを加圧したままで500℃になる通電を3回繰り返す固相焼結を行い、バリ取り後、フクレテストし、その後3μmNi・Bメッキを行い、ハンダ付のボイド品質の評価を行った。
結果を表１に示す。
(Example 3; heat dissipation substrate of Ag-Ti-diamond-residual Cu, sample No. 24)
10vol% Ag, 37vol% Cu, 3vol% Ti, 30vol% ・ 100μm and 20vol% ・ 30μm diamond powder are mixed and pressed using a 25mm x 25mm mold at a pressure of 500MPa, then held at a vacuum of 1000 ° C for 60 minutes After the liquid phase sintering, the composite material is plated with a metal layer of 100 μm Cu, and then the material 1 is placed in the ceramic jig 4 of FIG. With 100MPa pressurization, energize and hold at 500 ° C for 2 seconds, perform solid phase sintering 3 times repeatedly with energization to reach 500 ° C with pressurization, deburr, perform fret test, then 3μmNi · B Plating was performed and the quality of soldered voids was evaluated.
The results are shown in Table 1.
（実施例４；Al−Si−Mg−ダイヤモンドの放熱基板、試料No. 27）
29vol%Al、10vol%Si、1vol%Mg 、60vol%・50μmダイヤモンド粉末を混合し、25mm×25mm金型を用いて圧力500MPaでプレス型押し後に窒素・温度600℃・60分で液相焼結を行い、その複合材の表層を研削しTiとNiを併せて0.3μm蒸着し更に金属層の10μmのNiメッキを施した後、HPで真空、温度450℃、圧力100MPa、10分保持で固相焼結を行い、バリ取り後、フクレテストを行い、その後3μmNi・Bメッキを行い、ハンダ付のボイド品質の評価を行った。
結果を表２に示す。
(Example 4; heat dissipation substrate of Al-Si-Mg-diamond, sample No. 27)
29vol% Al, 10vol% Si, 1vol% Mg, 60vol% ・ 50μm diamond powder is mixed, and liquid phase sintering is performed at a pressure of 500MPa using a 25mm x 25mm die and after pressing with nitrogen at a temperature of 600 ℃ for 60 minutes. After grinding the surface layer of the composite material, depositing 0.3 μm of Ti and Ni together and applying 10 μm of Ni plating of the metal layer, vacuum with HP, temperature 450 ° C, pressure 100 MPa, hold for 10 minutes and fix Phase sintering was performed, deburring was performed, a blister test was performed, and then 3 μm Ni · B plating was performed to evaluate the void quality with solder.
The results are shown in Table 2.
（実施例５；PKGの放熱基板に半導体デバイスを搭載した半導体モジュールの評価）
実施例３の熱膨張係数8.3ppm/Kで熱伝導度555W/m・Kの放熱基板にセラミックとコバール等の部材を水素中・温度750℃で銀ろう付け後に剥離や割れのない確認したPKGを作り、それに10mm×10mm×0.7mmのSiデバイスの金属電極を高温AuSn(280℃)ハンダを300℃で接合し超音波でボイド面積が3%以下であることを確認した半導体モジュールを製作しヒートサイクルテスト(-40〜125℃、3000回)を行った。併せて、比較のため同寸法の実施例３と同じ熱膨張係数8.3ppm/Kで熱伝導度200W/m・Kの20wt%CuWの放熱基板で同じPKGを作りデバイスを搭載してヒートサイクルテスト(-40〜125℃、3000回)を行った。
結果、いずれの試料も剥離や割れ等の問題は起こらなかった。
(Example 5: Evaluation of a semiconductor module in which a semiconductor device is mounted on a PKG heat dissipation board)
PKG confirmed to be free from peeling and cracking after brazing silver and brazing ceramics and Kovar on a heat dissipation substrate with thermal expansion coefficient of 8.3 ppm / K and thermal conductivity of 555 W / m · K in Example 3 at a temperature of 750 ° C. A 10mm x 10mm x 0.7mm Si device metal electrode was joined to it with high-temperature AuSn (280 ° C) solder at 300 ° C, and a semiconductor module was confirmed that the void area was 3% or less by ultrasound. A heat cycle test (-40 to 125 ° C., 3000 times) was performed. In addition, for comparison, the same PKG is formed on a 20 wt% CuW heat dissipation board with the same thermal expansion coefficient of 8.3 ppm / K as in Example 3 and a thermal conductivity of 200 W / m · K. (-40 to 125 ° C., 3000 times).
As a result, no problem such as peeling or cracking occurred in any of the samples.
実施例１，２，３
実施例４
比較例
（今回開示の解釈-1）
これにより将来的な高性能半導体モジュールに対応できる高性能放熱基板の要求を満たすことができる。
(Interpretation of this disclosure-1)
As a result, it is possible to satisfy the demand for a high-performance heat dissipation substrate that can support future high-performance semiconductor modules.
（今回開示の解釈-2）
なお、本発明は現形態に限定されるものではなく本発明の目的を達成できる範囲での形態は本発明に含まれる。本発明を実施する際の具体的な構造や形態等は本発明の目的を達成できる範囲内で他の構造でもよい。例えば他の製法の金属ダイヤモンドの放熱基板のメッキ品質の確保にも本発明は応用できる。
(Interpretation of this disclosure-2)
In addition, this invention is not limited to the present form, The form in the range which can achieve the objective of this invention is included in this invention. The specific structure, form, etc. when carrying out the present invention may be other structures as long as the object of the present invention can be achieved. For example, the present invention can also be applied to ensure the plating quality of a heat-radiating substrate made of metal diamond by another manufacturing method.
（今回開示の解釈-3）
今回開示された実施形態及び実施例はすべての点で例示であって制限的なものでないと考えられるべきである。上記した説明でなく特許請求範囲によって示される。
(Interpretation of this disclosure-3)
It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. It is shown not by the above description but by the scope of claims.
１…金属と添加金属及びダイヤモンドからなる複合材に金属層を形成した素材
２…上下する上電極
３…下電極
４…セラミック治具
５…溶接機電源
６…水
７…ダイヤモンド
８…金属層
９…放熱基板の断面拡大写真
DESCRIPTION OF SYMBOLS 1 ... The raw material which formed the metal layer in the composite material which consists of a metal, an additive metal, and diamond 2 ... Up-and-down upper electrode 3 ... Lower electrode 4 ... Ceramic jig 5 ... Welding machine power supply 6 ... Water 7 ... Diamond 8 ... Metal layer 9 ... Magnified cross section of heat dissipation board
Claims (11)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2015172325A JP2016082224A (en) | 2015-09-01 | 2015-09-01 | Heat dissipation substrate and module for semiconductor using the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2015172325A JP2016082224A (en) | 2015-09-01 | 2015-09-01 | Heat dissipation substrate and module for semiconductor using the same |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2014207809A Division JP5807935B1 (en) | 2014-10-09 | 2014-10-09 | Heat dissipation board and semiconductor module using it |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2016082224A true JP2016082224A (en) | 2016-05-16 |
Family
ID=55959144
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2015172325A Pending JP2016082224A (en) | 2015-09-01 | 2015-09-01 | Heat dissipation substrate and module for semiconductor using the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2016082224A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107460393A (en) * | 2017-07-26 | 2017-12-12 | 界首市绿暄照明科技有限公司 | A kind of LED lamp base material of low thermal coefficient of expansion |
| CN109659280A (en) * | 2018-12-27 | 2019-04-19 | 西安中车永电电气有限公司 | A kind of compression joint type IGBT internal enclosing structure |
| CN110577399A (en) * | 2019-07-12 | 2019-12-17 | 北京科技大学 | Multi-field coupling flash sintering system based on induction heating |
-
2015
- 2015-09-01 JP JP2015172325A patent/JP2016082224A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107460393A (en) * | 2017-07-26 | 2017-12-12 | 界首市绿暄照明科技有限公司 | A kind of LED lamp base material of low thermal coefficient of expansion |
| CN109659280A (en) * | 2018-12-27 | 2019-04-19 | 西安中车永电电气有限公司 | A kind of compression joint type IGBT internal enclosing structure |
| CN110577399A (en) * | 2019-07-12 | 2019-12-17 | 北京科技大学 | Multi-field coupling flash sintering system based on induction heating |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP6028987B2 (en) | Heat dissipation substrate and method for manufacturing the heat dissipation substrate | |
| TWI452143B (en) | Aluminum-diamond based complex and method for manufacturing the same | |
| JP5988977B2 (en) | Heat dissipation parts for semiconductor elements | |
| KR101153107B1 (en) | Metal substrate/metal impregnated carbon composite material structure and method for manufacturing said structure | |
| JP5759152B2 (en) | Aluminum-diamond composite and method for producing the same | |
| JP4791487B2 (en) | Semiconductor device mounting substrate, semiconductor device using the same, and method of manufacturing semiconductor device mounting substrate | |
| JPWO2016035789A1 (en) | Heat dissipation parts for semiconductor elements | |
| JP2017075397A (en) | Heat radiation substrate and manufacturing method of heat radiation substrate | |
| JP6108987B2 (en) | Connection structure | |
| JP6083634B2 (en) | Heat dissipation substrate and method for manufacturing the heat dissipation substrate | |
| JP2012158783A (en) | Aluminum-diamond composite, and method for production thereof | |
| JP2012158817A (en) | Aluminum-diamond composite and method for production thereof | |
| JP2016082224A (en) | Heat dissipation substrate and module for semiconductor using the same | |
| WO2018123380A1 (en) | Heat dissipation component for semiconductor element | |
| WO2015163395A1 (en) | Aluminum-diamond composite, and heat dissipating component using same | |
| JP2011139000A (en) | Power module structure and method of manufacturing the same | |
| JP6105262B2 (en) | Aluminum-diamond composite heat dissipation parts | |
| JP2010278171A (en) | Power semiconductor and manufacturing method of the same | |
| JP2016111328A (en) | Heat-dissipating substrate, and semiconductor package and semiconductor module using the same | |
| JP2012171838A (en) | Method for producing aluminum-silicon carbide composite | |
| JP2024041251A (en) | Electronic component joining method |