JP3798136B2

JP3798136B2 - Support jig for substrate heat treatment

Info

Publication number: JP3798136B2
Application number: JP35481597A
Authority: JP
Inventors: 博至木村; 英一篠宮
Original assignee: Shin Etsu Quartz Products Co Ltd
Current assignee: Shin Etsu Quartz Products Co Ltd
Priority date: 1997-12-24
Filing date: 1997-12-24
Publication date: 2006-07-19
Anticipated expiration: 2017-12-24
Also published as: JPH11186181A

Description

【０００１】
【発明の属する技術分野】
本発明は、液晶、太陽電池、半導体ウエーハ等の矩形、円形の基盤の熱処理に使用される熱処理用支持治具に関する。
【０００２】
【従来の技術】
液晶や太陽電池及びＬＳＩ等は、ガラスやシリコン、化合物等の基盤の表面に、特定の作用物質のドープや打ち込み、化学蒸着（以下、ＣＶＤという）等による積層等の薄膜形成処理を行った後に、発色素子、起電素子、整流、増幅、蓄電等の回路素子を形成して製造されるが、これらの薄膜形成処理は、一般に円筒またはドーム状の熱処理容器内で４００〜１３００℃の高温下で行われている。
【０００３】
これらの熱処理は、複数の基盤を支持治具に載置して行われるが、このような支持治具には、耐熱性に優れ、また基盤上に欠陥の少ない均質な薄膜を形成するために不可欠な、金属不純物の少ない石英ガラス等の素材が使用されている。
この支持治具は、複数の基盤を垂直に立てて横に並べたものもあるが、近年の基盤の大型化から、現在では複数の基盤を上下方向に略水平に間隔を空けて支持する縦型の支持治具が多用されている。この縦型の支持治具は、熱処理用容器の床面積を小さくでき、かつ容器の構造を簡単にできるという利点がある。
【０００４】
【発明が解決しようとする課題】
近年、基盤から製造される装置、例えばＬＳＩ等の半導体では、集積度があがり、より精密な薄膜形成が必要となってきているため、使用する熱処理用容器や支持治具等から放出される不純物の外に、微細な塵埃等の基盤への付着による欠陥が問題となっている。
これらの塵埃は、基盤上に薄膜を形成する際に、石英ガラス等の支持治具の表面に、同じかあるいは類似の薄膜が形成され、この薄膜の熱膨張の大きさ（１〜１０×１０^-6／℃）に比較して、支持治具の素材である石英ガラスの熱膨張（０．５×１０^-6／℃）が小さすぎることから生ずる熱膨張の差により、支持治具の表面に形成された薄膜にひび割れが生じ、それが破損、飛散して発生するものと考えられている。
【０００５】
そこで、これらの薄膜との熱膨張の差が小さく、耐熱性に優れた焼結炭化珪素製の支持治具の使用が試みられていたが、焼結炭化珪素の表面はポーラス（多孔質）であるため、ここから塵埃が発生したり、不純物が放出されたりする問題があった。その後、この問題は、ポーラスな炭化珪素表面に緻密なＣＶＤ膜を形成することにより改善することが可能になった。
【０００６】
しかしながら、炭化珪素からなる支持治具には、尚、以下の問題点が残されている。
大型基盤を処理するため支持治具も大型化し、さらに生産性をあげるため、熱処理の前後で支持治具の急熱、急冷を行うが、この温度変化に熱膨張率が大きく、熱衝撃に弱い炭化珪素製の支持治具は対応できず破損する可能性がある。
特に、縦型の支持治具を炭化珪素で作ろうとすると、基盤を積重ね状に支持する複雑な構造となるため、熱歪みや形状の歪みが生じやすいため製造が難しく、また支持治具自体が極めて高価なものとなる。
さらに、縦型の支持治具は構造が複雑なため、ＣＶＤ膜を全体に均質に形成しにくく、またＣＶＤ膜のピンホール部分から塵埃や不純物による汚染の可能性があるので、特に高度なＣＶＤ膜形成技術が必要となり、支持治具のコストがさらに高価なものとなる。
【０００７】
本発明の課題は、急熱、急冷にも形状が安定していて破損がなく、また不純物の放出や、薄膜生成にも塵埃が発生することなく、製造が容易で低価格な縦型の基盤熱処理用支持治具を提供することにある。
【０００８】
【課題を解決するための手段】
本発明の熱処理用支持治具では、複数の被熱処理基盤の周縁部を受け入れて支持する少なくとも二本以上の支柱と、各支柱の端部を連結固定する固定部材から構成されている。
支柱と固定部材を別体とすることにより、それぞれの形状が単純になるため、製造が容易になり、製品コストを下げることができる。
【０００９】
また、各支柱に、基盤の熱処理中に支持治具表面に形成される薄膜（例えばポリシリコン、窒化珪素、シリケートガラス等）と同等の熱膨張率である１〜１０×１０^-6／℃の熱膨張率を有する素材を使用することで、熱膨張差による薄膜の剥離等による塵埃の発生や破損を防止している。
このような熱膨張率が薄膜に近い素材としては、炭化珪素、シリコン、窒化珪素等が挙げられる。
【００１０】
さらに、固定部材には熱膨張率が０．２〜０．８×１０^-6／℃の素材を使用している。固定部材を、熱膨張率の小さい素材で形成することにより、急激な温度変化に対しても基盤の支持手段を有する支柱の位置関係に狂いを生じにくくし、安定した熱処理が可能となる。
固定部材は、支柱に比べて温度分布や炉の開放時の温度変化が生じやすい炉の均熱範囲境界付近に配置されるため、熱膨張率の小さな素材を使用することにより破損を防止できる。
固定部材の素材としては、上記範囲の熱膨張率を有し、耐熱性に優れ、有害な金属不純物を含まず、加工性に優れた石英ガラス、焼結石英等が挙げられる。
【００１１】
基盤の支持手段としては、各支柱の対向面に、個々の基盤の周縁部を受け入れ支持する溝を上下方向に間隔を空けて形成すると良い（請求項２）。
支柱を、上記した炭化珪素、シリコン、窒化珪素等の素材で形成した場合、複雑な形状を正確に作るのは難しく、高精度の必要な基盤支持部を形成しにくい。
そこで、ダイヤモンドカッターなどを用いて、機械的に溝を形成することにより、例えば焼結時に基盤支持用の突起などを形成するよりも精度の高い（支持ピッチや支持部の面積など）基盤支持部が得られる。
【００１２】
支柱は、炭化珪素膜にてＣＶＤコートされた炭化珪素で形成し、かつ固定部材は、石英ガラスで形成すると良い（請求項３）。
支柱には、上記のように炭化珪素、シリコン等の素材が用いられるが、その中でも、薄膜（シリコン膜やガラス膜）の洗浄を行った際に浸食されない素材が望ましい。これは、支柱の溝の内面に薄膜が付着して厚くなり、溝幅が狭くなって基盤が載置できなくなったり、対向する支柱の溝幅の広狭により段差ができて、載置した基盤ががたついたりするため、定期的な洗浄が必要となるからである。
その点で炭化珪素は、ＨＦを含んだ薬液（例えば、ＨＦ４〜２０％）による膜の除去洗浄にも浸食されず、最初の精度と形状を維持することができるので、最も適切な素材といえる。
【００１３】
支柱に炭化珪素を用いる場合、炭化珪素のＣＶＤ膜を表面コートすることにより、炭化珪素内部からの不純物や塵埃等の放出を防止できる。
また、固定部材に、石英ガラスを用いると、ダイヤモンド砥石やカッターによる研削切断加工の他、火炎等の熱による溶接、成形加工もできるため、加工が容易で後述の嵌合構造が容易に作製できる。
このように、本発明の基盤熱処理用支持治具では、支柱に炭化珪素膜でＣＶＤコートされた炭化珪素を用い、固定部材に石英ガラスを用いるのが最も好ましい組み合わせである。
【００１４】
支柱と固定部材の連結固定手段を、支柱の端部に形成した凹部に対応する固定部材の凸状の接続部（以下、凸部という。）を挿嵌する嵌合構造とすると良い（請求項４）。
熱膨張率の大きい支柱に凹部を設け、熱膨張率の小さい固定部材に凸部を設けた構成とすることにより、急激な温度上昇の際に嵌合部内方の膨張による破損を防止できる。また、常温での嵌合組立時に遊びを最小にすることができるので精度の良い支持治具が得られる。
上記嵌合構造は、着脱が可能な構造とするのが望ましい。洗浄などの際に分解して別々に洗浄でき、修理交換も容易となるからである。また、支柱と固定部材の連結手段を上記嵌合構造とすることにより、連結時の支柱の位置精度が維持しやすくなる。
【００１５】
【発明の実施の形態】
以下、本発明の基盤熱処理用支持治具の一実施の形態を、図面に基づいて具体的に説明する。
図１は、本発明の基盤熱処理用支持治具の一例の斜視図であり、図２は、図１の部分拡大断面図である。図３は、本発明の基盤熱処理用支持治具の他の例の斜視図であり、図４は、本発明の基盤熱処理用支持治具の別の例の組立手順を示す斜視図である。また、図５の（ａ）、（ｂ）及び図６の（ａ）、（ｂ）は、固定部材の別の例の平面図と側面図である。
【００１６】
図１、図２に示す本発明の基盤熱処理用支持治具は、４本の同形の長尺円筒状の支柱１と、各支柱の上端部と下端部をそれぞれ連結固定する円板状の固定部材２、２’から構成され、各支柱１の対向面には、載置する複数の基盤３の周縁部を受け入れ支持する溝４が上下方向に等間隔に形成されている。
上記４本の支柱は、基盤の出し入れに支障がないように固定部材２、２’の半円領域内の周縁にそって等間隔に立設されている。
【００１７】
支柱１は、いずれも熱膨張率１〜１０×１０^-6／℃の素材で形成され、上下の固定部材２、２’は、熱膨張率が０．２〜０．８×１０^-6／℃の素材で形成されている。
また、支柱１と固定部材２、２’の連結固定手段は、下側の固定部材２の支柱連結部に形成された凸部に支柱の中心孔６を嵌め込み、上側の固定部材２’に形成された凸部５を、支柱１の中心孔６に挿嵌して固定する。
【００１８】
図３に示す基盤熱処理用支持治具は、固定部材２２、２２’の中央に大きな貫通孔２３を有する円輪板で形成され、その固定部材には、円筒状の支柱２１の中心孔２４に挿嵌し得る凸部２５が等間隔に形成された構成である。
【００１９】
図４は、支柱と固定部材の別の例の連結固定手段を示している。
この連結固定手段では、円筒状の支柱３１の中心孔に挿嵌し得る４本の軸棒３５が、円板状の下側の固定部材３２に一体に立設され、この軸棒３５に支柱３１の中心孔を挿嵌し、支柱３１の中心孔からはみ出た軸棒３５の先端部３６に、対応する上側の固定部材３２’に開けられた孔３７を嵌合した後、溶接３８して連結固定している。
【００２０】
また、図５、図６で示す連結固定手段は、固定部材４２、４３を棒状に形成しており、図５は五角形状に、図６は、大の字形に形成し、支柱との連結部には支柱の中心孔に挿嵌し得る凸部４４、４５がそれぞれ形成されている。
固定部材をこのような棒状に形成することにより、支持治具の軽量化が図られ、また支持治具全体の熱容量を小さくして処理の高速化が図れる。
【００２１】
【実施例】
次に、本発明の基盤熱処理用支持治具を用いた実施例及び比較例をあげる。
［実施例１］
（支柱の作製）
既存の反応焼結法で得られた、直径２０ｍｍ、肉厚６ｍｍ、長さ６４０ｍｍの円筒状のＳｉＣ管に、幅３ｍｍ、深さ４ｍｍ、ピッチ６ｍｍの溝を、ダイヤモンドカッターで１００溝切った。
溝カットしたＳｉＣ管を２５％ＨＣｌにて１時間洗浄し、１４ＭΩの純水ですすぎ洗浄した後、１０％ＨＦ溶液にて３０分の洗浄を行い、さらに１４ＭΩの純水ですすいだ後、真空乾燥機にて１２０℃、１時間の乾燥を行った。
次いで、ＣＨ₃ ＳｉＣｌ₃ を、Ｈ₂ ガスをキャリヤガスとして用いて、減圧状態で蒸着する既存のＣＶＤ法により、前記溝付きのＳｉＣ管を約８０μｍの炭化珪素膜にてＣＶＤコートして、支柱を４本作製した。
【００２２】
（固定部材の作製）
天然の珪砂を、純化後電気加熱により溶融した天然石英ガラスを用い、酸素−水素バーナーやダイヤモンド砥石にてガラス細工加工を行い、肉厚１０ｍｍ、中央に直径１５０ｍｍの貫通穴を有する外径２３３ｍｍの石英ガラス円輪板を作製し、さらに上記支柱の内径に挿嵌し得るφ７．９５ｍｍ、高さ１５ｍｍの４カ所の凸部を有する固定部材を２個作製した。
上記によって作製した支柱と固定部材を、支柱の中心孔に固定部材の凸部を挿嵌させて組立て、図３に示すような本発明の基盤熱処理用支持治具を得た。
【００２３】
［比較例１］
実施例１と同様な方法で、同一の形状の溝付きＳｉＣ管を約８０μｍの炭化珪素膜にてＣＶＤコートした支柱を４本作製した。
また、同様に既存の反応焼結法を用い、実施例１と同形状の炭化珪素質の固定部材を２個作製し、これらを実施例１と同様な方法で組立て、図３に示す基盤熱処理用支持治具を得た。
【００２４】
［比較例２］
天然の珪砂を純化した後、電気加熱により溶融して天然石英ガラスを作製し、これを用いて、酸素−水素バーナーやダイヤモンド砥石にてガラス細工加工を行い、図３に示す実施例１と同形状で、支柱と固定部材がともに石英ガラスからなる基盤熱処理用支持治具を得た。
【００２５】
［実施例２］
実施例１と同じ素材で、凹凸の嵌合構造を逆にした図７に示す支柱と固定部材を作製した。まず、実施例１と同様な方法で同一の形状の溝付きＳｉＣ管を約８０μｍの炭化珪素膜にてＣＶＤコートした支柱５１を４本作製した。
次に天然の珪砂を、純化後電気加熱により溶融した天然石英ガラスを用い、酸素−水素バーナーやダイヤモンド砥石にてガラス細工加工を行い、肉厚１０ｍｍ、中央に直径１５０ｍｍの貫通穴を有する外径２３３ｍｍの円輪板に成形した後、その平板上に支柱の端部を挿嵌し得るφ２０．０５ｍｍ、高さ８ｍｍの４カ所の座グリを有する凹部５５を有する固定部材５２［図７(a) ］を２個作製した。これらを組立て、図７(b) に示す、基盤熱処理用支持治具を得た。
【００２６】
（作用の確認）
実施例１、２、比較例１、２のそれぞれの基盤熱処理用治具に、φ２００ｍｍウエハーを搭載して、既存のポリシリコンのＣＶＤ処理を繰り返し行い、膜を堆積させた。
【００２７】
（結果）
比較例１の支持治具は、数度のＣＶＤ処理後、炭化珪素の連結手段の下側円輪板に、クラックが入っているのが確認された。
このため、その後の処理では、円輪板がクラックの伸長に伴いゆがみ、搭載したウエハーが脱落する、あるいは傷が発生するなどのトラブルがあり、１０μｍの処理で使用を中止した。
また、クラック発見後、ウエハー上にはパーティクルが見られ、これらは電子顕微鏡等による表面探査では主成分がＣやＳｉ、Ｆｅであることが確認された。
上記パーティクルは、クラックが発生したＳｉＣ部分の内部から飛散したものと考えられる。
【００２８】
比較例２の支持治具では、約２５μｍの膜付けを行った時点で、支柱の膜に細かなクラックが見られ、一部剥離が確認された。また、その後のウエハーの８０％に何らかのパーティクルに起因する欠陥が見られた。これらのパーティクルは、主にＳｉやＳｉＯ、ＳｉＯ₂ 等からなっていることがわかった。また、４０μｍの膜厚の処理後、降温時に治具は支柱部分から破損した。
【００２９】
実施例２の支持治具では、８０μｍの処理まで使用することが出来たが、石英ガラスの円輪板にＳｉＣの支柱が嵌合している部分にクラックが見られたので、そこで使用を中止した。
実施例１では、１００μｍの膜付けまで試験を行ったが、特にパーティクルやクラックなどの異常は見られなかった。
【００３０】
以上のように本発明の実施例１による支持治具では、急熱、急冷にも形状が安定して破損が無く、また不純物の放出も無く、さらには薄膜形成時に塵埃も発生しないので、結果として支持治具を長時間使用できる。
また、固定部材の比較例１のように連結手段などの複雑な部分が炭化珪素等の高価な部品でないので、安く、容易に作製することができる。
【００３１】
【発明の効果】
本発明によれば、急熱、急冷にも形状が安定して、破損や不純物の放出が無く、薄膜生成にも塵埃が発生することなく、また構造が簡単で製造が容易かつ低価格な縦型の基盤熱処理用治具が得られる。
【図面の簡単な説明】
【図１】本発明の基盤熱処理用支持治具の一例の斜視図である。
【図２】図１の部分拡大断面図である。
【図３】本発明の基盤熱処理用支持治具の他の例の分解した状態の斜視図である。
【図４】本発明の基盤熱処理用支持治具の別の例の分解斜視図である。
【図５】（ａ）は、固定部材の他の例の平面図、（ｂ）は、その側面図である。
【図６】（ａ）は、固定部材の別の例の平面図、（ｂ）は、その側面図である。
【図７】（ａ）は、固定部材の別の例を示す斜視図、（ｂ）は、この固定部材を用いた本発明の基盤熱処理用支持治具の斜視図である。
【符号の説明】
１、２１、３１、５１支柱
２，２’、２２，２２’、３２，３２’、４２、４３、５２固定部材
３基盤
４溝
５、２５凸部
６中心孔
２３貫通孔
２４中心孔
３５軸棒
３６軸棒の先端部
３７孔
４４、４５凸部
５５凹部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat treatment support jig used for heat treatment of a rectangular or circular substrate such as a liquid crystal, a solar cell, and a semiconductor wafer.
[0002]
[Prior art]
Liquid crystals, solar cells, LSIs, etc., after performing thin film formation processing such as laminating by doping or implanting specific active substances, chemical vapor deposition (hereinafter referred to as CVD), etc. on the surface of the substrate such as glass, silicon, and compounds These are formed by forming circuit elements such as coloring elements, electromotive elements, rectification, amplification, and electricity storage. These thin film formation processes are generally performed at a high temperature of 400 to 1300 ° C. in a cylindrical or dome-shaped heat treatment container. It is done in
[0003]
These heat treatments are carried out by placing a plurality of substrates on a support jig. In order to form a homogeneous thin film with excellent heat resistance and few defects on the substrate. Indispensable materials such as quartz glass with few metal impurities are used.
Some of these support jigs have a plurality of bases arranged vertically and arranged side by side. However, due to the recent increase in size of the bases, there is a vertical support that supports the plurality of bases in the vertical direction at approximately horizontal intervals. Many mold support jigs are used. This vertical support jig is advantageous in that the floor area of the heat treatment container can be reduced and the structure of the container can be simplified.
[0004]
[Problems to be solved by the invention]
In recent years, devices manufactured from a substrate, for example, semiconductors such as LSIs, have become more integrated and require more precise thin film formation. Therefore, impurities released from heat treatment containers and supporting jigs to be used In addition to this, defects due to adhesion of fine dust and the like to the substrate are problematic.
When these dusts form a thin film on the substrate, the same or similar thin film is formed on the surface of a supporting jig such as quartz glass. The magnitude of thermal expansion of this thin film (1 to 10 × 10 ^-6 / ° C), the surface of the support jig is caused by the difference in thermal expansion caused by the fact that the thermal expansion (0.5 × 10 ^-6 / ° C) of the quartz glass that is the material of the support jig is too small. It is thought that cracks occur in the thin film formed on the surface of the film, which breaks and scatters.
[0005]
Therefore, it has been attempted to use a support jig made of sintered silicon carbide having a small difference in thermal expansion from these thin films and having excellent heat resistance, but the surface of the sintered silicon carbide is porous. For this reason, there is a problem that dust is generated or impurities are emitted from here. Thereafter, this problem can be improved by forming a dense CVD film on the porous silicon carbide surface.
[0006]
However, the following problems remain in the support jig made of silicon carbide.
In order to process large substrates, the support jig is also enlarged, and in order to increase productivity, the support jig is rapidly heated and cooled before and after heat treatment. However, the thermal expansion coefficient is large due to this temperature change, and it is weak against thermal shock. The support jig made of silicon carbide cannot be handled and may be damaged.
In particular, if a vertical support jig is made of silicon carbide, it becomes a complicated structure that supports the substrate in a stacked state, so that it is difficult to manufacture because the thermal distortion and shape distortion are likely to occur. Extremely expensive.
Furthermore, since the vertical support jig has a complicated structure, it is difficult to form a CVD film uniformly on the entire surface, and the pinhole portion of the CVD film may be contaminated with dust or impurities. A film forming technique is required, and the cost of the support jig is further increased.
[0007]
The object of the present invention is a vertical base that is easy to manufacture and inexpensive, with a stable shape that does not break even during rapid heating and rapid cooling, and without dust generation during the release of impurities and thin film formation. The object is to provide a heat treatment support jig.
[0008]
[Means for Solving the Problems]
The heat treatment support jig of the present invention includes at least two or more struts that receive and support the peripheral portions of a plurality of heat treatment bases, and a fixing member that connects and fixes end portions of the respective struts.
By making the support and the fixing member separate, each shape becomes simple, so that the manufacturing becomes easy and the product cost can be reduced.
[0009]
Further, each column has a thermal expansion coefficient of 1 to 10 × 10 ⁻⁶ / ° C. which is equivalent to that of a thin film (eg, polysilicon, silicon nitride, silicate glass, etc.) formed on the surface of the support jig during the heat treatment of the substrate. By using a material having a coefficient of thermal expansion, dust generation and damage due to peeling of a thin film due to a difference in thermal expansion are prevented.
Examples of such a material having a coefficient of thermal expansion close to that of a thin film include silicon carbide, silicon, and silicon nitride.
[0010]
Further, a material having a thermal expansion coefficient of 0.2 to 0.8 × 10 ⁻⁶ / ° C. is used for the fixing member. By forming the fixing member with a material having a small coefficient of thermal expansion, it is possible to prevent the positional relationship of the support columns having the base support means from being out of order even when the temperature changes suddenly, and to perform stable heat treatment.
Since the fixing member is disposed near the boundary of the soaking range of the furnace where the temperature distribution and the temperature change at the time of opening of the furnace are likely to occur as compared with the support column, breakage can be prevented by using a material having a small coefficient of thermal expansion.
Examples of the material of the fixing member include quartz glass and sintered quartz having a thermal expansion coefficient in the above range, excellent heat resistance, no harmful metal impurities, and excellent workability.
[0011]
As the base support means, grooves for receiving and supporting the peripheral edge portions of the individual bases may be formed on the opposing surfaces of the support columns at intervals in the vertical direction.
When the support column is formed of a material such as silicon carbide, silicon, or silicon nitride as described above, it is difficult to accurately form a complicated shape, and it is difficult to form a necessary base support portion with high accuracy.
Therefore, by using a diamond cutter or the like to form grooves mechanically, for example, a base support part with higher accuracy (such as support pitch and area of the support part) than forming base support protrusions during sintering. Is obtained.
[0012]
The support column is preferably formed of silicon carbide CVD-coated with a silicon carbide film, and the fixing member is preferably formed of quartz glass.
As described above, a material such as silicon carbide or silicon is used for the support column. Among them, a material that is not eroded when a thin film (silicon film or glass film) is cleaned is preferable. This is because the thin film adheres to the inner surface of the pillar groove and becomes thicker, the groove width becomes narrower and the board cannot be placed. This is because regular cleaning is necessary because of rattling.
In this respect, silicon carbide is not eroded even by removal and cleaning of the film with a chemical solution containing HF (for example, HF 4 to 20%), and can maintain the initial accuracy and shape, so that it can be said to be the most suitable material. .
[0013]
When silicon carbide is used for the support, the surface of the silicon carbide CVD film can prevent impurities and dust from being released from the inside of the silicon carbide.
In addition, if quartz glass is used for the fixing member, it can be easily welded and formed by heat such as flame in addition to grinding and cutting with a diamond grindstone or cutter, so that the fitting structure described later can be easily produced. .
Thus, in the base heat treatment support jig of the present invention, the most preferable combination is to use silicon carbide CVD-coated with a silicon carbide film for the support and quartz glass for the fixing member.
[0014]
The connecting and fixing means of the support column and the fixing member may be a fitting structure in which a convex connection portion (hereinafter referred to as a convex portion) of the fixing member corresponding to the concave portion formed at the end portion of the post is inserted. 4).
By adopting a structure in which a concave portion is provided on a support column having a high thermal expansion coefficient and a convex portion is provided on a fixing member having a low thermal expansion coefficient, it is possible to prevent damage due to expansion inside the fitting portion when the temperature rises rapidly. Moreover, since play can be minimized during fitting assembly at room temperature, a highly accurate support jig can be obtained.
The fitting structure is desirably a detachable structure. This is because it can be disassembled and cleaned separately at the time of cleaning, etc., and repair and replacement are facilitated. In addition, since the connecting means between the support column and the fixing member has the above-described fitting structure, the position accuracy of the support column during connection can be easily maintained.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a base heat treatment support jig according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view of an example of the base heat treatment support jig of the present invention, and FIG. 2 is a partially enlarged sectional view of FIG. FIG. 3 is a perspective view of another example of the base heat treatment support jig of the present invention, and FIG. 4 is a perspective view showing an assembly procedure of another example of the base heat treatment support jig of the present invention. FIGS. 5A and 5B and FIGS. 6A and 6B are a plan view and a side view of another example of the fixing member.
[0016]
The support jig for base heat treatment of the present invention shown in FIG. 1 and FIG. 2 is composed of four identical long cylindrical columns 1 and disk-shaped fixings that connect and fix the upper end and lower end of each column. Grooves 4 configured to receive and support the peripheral portions of the plurality of substrates 3 to be placed are formed at equal intervals in the vertical direction on the opposing surface of each support column 1.
The four struts are erected at equal intervals along the peripheral edge in the semicircular region of the fixing members 2 and 2 ′ so as not to interfere with the insertion and removal of the base.
[0017]
The struts 1 are each made of a material having a thermal expansion coefficient of 1 to 10 × 10 ⁻⁶ / ° C., and the upper and lower fixing members 2 and 2 ′ have a thermal expansion coefficient of 0.2 to 0.8 × 10 ⁻⁶ / It is made of a material at ℃.
Further, a connecting and fixing means for the support column 1 and the fixing members 2 and 2 ′ is formed in the upper fixing member 2 ′ by fitting the center hole 6 of the support column into the convex portion formed in the support connecting portion of the lower fixing member 2. The projected part 5 is inserted and fixed in the center hole 6 of the column 1.
[0018]
The base heat treatment support jig shown in FIG. 3 is formed of an annular plate having a large through-hole 23 in the center of the fixing members 22 and 22 ′, and the fixing member is formed in the central hole 24 of the cylindrical column 21. It is the structure by which the convex part 25 which can be inserted is formed at equal intervals.
[0019]
FIG. 4 shows another example of the connecting and fixing means of the support column and the fixing member.
In this connecting and fixing means, four shaft rods 35 that can be inserted into the center hole of the cylindrical column 31 are erected integrally with a disk-like lower fixing member 32, and the column rod 35 is supported by the column rod 35. The center hole 31 is inserted and the hole 37 opened in the corresponding upper fixing member 32 ′ is fitted to the tip portion 36 of the shaft bar 35 protruding from the center hole of the column 31. It is connected and fixed.
[0020]
In addition, the connecting and fixing means shown in FIGS. 5 and 6 has the fixing members 42 and 43 formed in a rod shape, FIG. 5 is formed in a pentagon shape, and FIG. Are formed with convex portions 44 and 45, respectively, which can be inserted into the center holes of the columns.
By forming the fixing member in such a rod shape, the weight of the support jig can be reduced, and the heat capacity of the entire support jig can be reduced to increase the processing speed.
[0021]
【Example】
Next, examples and comparative examples using the support jig for substrate heat treatment of the present invention will be given.
[Example 1]
(Production of support)
In a cylindrical SiC tube having a diameter of 20 mm, a wall thickness of 6 mm, and a length of 640 mm obtained by an existing reaction sintering method, 100 grooves were cut with a diamond cutter, a width of 3 mm, a depth of 4 mm, and a pitch of 6 mm.
The groove-cut SiC tube is washed with 25% HCl for 1 hour, rinsed with 14 MΩ pure water, washed with 10% HF solution for 30 minutes, further rinsed with 14 MΩ pure water, and then vacuumed. Drying was performed at 120 ° C. for 1 hour in a dryer.
Next, CH ₃ SiCl ₃ is CVD-coated on the grooved SiC tube with an about 80 μm silicon carbide film by an existing CVD method in which H ₂ gas is used as a carrier gas and vapor-deposited under reduced pressure. 4 were produced.
[0022]
(Fixing member production)
Using natural quartz glass obtained by melting natural silica sand by electric heating after purification, glass work is performed with an oxygen-hydrogen burner or diamond grindstone, and the outer diameter is 233 mm with a through hole having a thickness of 10 mm and a diameter of 150 mm in the center. A quartz glass ring plate was prepared, and two fixing members having four convex portions of φ7.95 mm and a height of 15 mm that could be inserted into the inner diameter of the column were prepared.
The strut and the fixing member produced as described above were assembled by inserting the convex portion of the fixing member into the center hole of the strut, and the base heat treatment support jig of the present invention as shown in FIG. 3 was obtained.
[0023]
[Comparative Example 1]
In the same manner as in Example 1, four struts were formed by CVD-coating a grooved SiC tube having the same shape with a silicon carbide film of about 80 μm.
Similarly, using the existing reaction sintering method, two silicon carbide-like fixing members having the same shape as in Example 1 were fabricated, and these were assembled in the same manner as in Example 1, and the base heat treatment shown in FIG. A support jig was obtained.
[0024]
[Comparative Example 2]
After natural silica sand is purified, it is melted by electric heating to produce natural quartz glass. Using this, glass work is performed with an oxygen-hydrogen burner or diamond grindstone, and the same as in Example 1 shown in FIG. A support jig for substrate heat treatment was obtained in which the support and the fixing member were both made of quartz glass.
[0025]
[Example 2]
The support | pillar and fixing member which were the same material as Example 1 and which reversed the fitting structure of the unevenness | corrugation shown in FIG. 7 were produced. First, four struts 51 were manufactured by CVD-coating a grooved SiC tube having the same shape with a silicon carbide film of about 80 μm in the same manner as in Example 1.
Next, natural quartz sand is purified, and natural quartz glass melted by electric heating is used for glass work with an oxygen-hydrogen burner or diamond grindstone. The outer diameter is 10 mm thick and has a through hole with a diameter of 150 mm in the center. After forming into a 233 mm annular plate, a fixing member 52 having recesses 55 having four countersinks of φ20.05 mm and a height of 8 mm, on which the end of the column can be inserted on the flat plate [FIG. )] Were produced. These were assembled to obtain a base heat treatment support jig shown in FIG. 7 (b).
[0026]
(Confirmation of action)
A φ200 mm wafer was mounted on each of the substrate heat treatment jigs of Examples 1 and 2 and Comparative Examples 1 and 2, and the existing polysilicon was subjected to CVD treatment repeatedly to deposit a film.
[0027]
(result)
The support jig of Comparative Example 1 was confirmed to have cracks in the lower ring plate of the silicon carbide connecting means after several CVD processes.
For this reason, in the subsequent processing, the annular plate was distorted as the cracks were extended, and there was a problem that the mounted wafer was dropped or scratched, and the use was stopped at the processing of 10 μm.
In addition, after the discovery of cracks, particles were observed on the wafer, and these were confirmed to be mainly composed of C, Si, and Fe by surface exploration using an electron microscope or the like.
It is considered that the particles are scattered from the inside of the SiC portion where the crack is generated.
[0028]
In the support jig of Comparative Example 2, when the film was applied to a thickness of about 25 μm, fine cracks were observed in the support film, and partial peeling was confirmed. In addition, defects caused by some particles were observed in 80% of the subsequent wafers. It was found that these particles are mainly composed of Si, SiO, SiO ₂ or the like. In addition, after the treatment with a film thickness of 40 μm, the jig was damaged from the column portion when the temperature was lowered.
[0029]
The support jig of Example 2 could be used up to a treatment of 80 μm, but cracks were found in the portion where the SiC support was fitted to the quartz glass ring plate, so the use was stopped there. did.
In Example 1, although the test was performed up to 100 μm film formation, no abnormalities such as particles and cracks were observed.
[0030]
As described above, in the support jig according to Example 1 of the present invention, the shape is stable and not damaged even in rapid heating and rapid cooling, no impurities are released, and no dust is generated when forming a thin film. As a support jig can be used for a long time.
In addition, since the complicated part such as the connecting means is not an expensive part such as silicon carbide as in Comparative Example 1 of the fixing member, it can be easily manufactured at low cost.
[0031]
【The invention's effect】
According to the present invention, the shape is stable even in rapid heating and rapid cooling, there is no breakage and no release of impurities, no dust is generated in the formation of a thin film, and the structure is simple, easy to manufacture, and inexpensive. A jig for base heat treatment of the mold is obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view of an example of a base heat treatment support jig according to the present invention.
FIG. 2 is a partially enlarged cross-sectional view of FIG.
FIG. 3 is an exploded perspective view of another example of the base heat treatment support jig of the present invention.
FIG. 4 is an exploded perspective view of another example of the base heat treatment support jig of the present invention.
5A is a plan view of another example of the fixing member, and FIG. 5B is a side view thereof.
6A is a plan view of another example of the fixing member, and FIG. 6B is a side view thereof.
7A is a perspective view showing another example of a fixing member, and FIG. 7B is a perspective view of a base heat treatment support jig of the present invention using the fixing member.
[Explanation of symbols]
1, 21, 31, 51 Posts 2, 2 ', 22, 22', 32, 32 ', 42, 43, 52 Fixing member 3 Base 4 Groove 5, 25 Protrusion 6 Center hole 23 Through hole 24 Center hole 35 Axis Rod 36 Axle rod tip 37 Hole 44, 45 Convex 55 Concave

Claims

In a support jig for heat treatment that holds multiple substrates to be heat-treated in the vertical direction at approximately horizontal intervals, at least two columns that receive and support the peripheral edge of the substrate and the ends of each column are connected and fixed. Each supporting column is made of a material having a thermal expansion coefficient of 1 to 10 × 10 ⁻⁶ / ° C., and the fixing member is made of a material having a thermal expansion coefficient of 0.2 to 0.8 × 10 ⁻⁶ / ° C. Each of the support columns and the fixing member is connected by a concave-convex fitting structure, a recess is formed at the end of the support column, and a convex connection portion is formed at a corresponding portion of the fixing member. Support jig.

2. A base heat treatment support jig according to claim 1, wherein a groove for receiving and supporting the peripheral edge of each base is formed on the opposing surface of each support column at intervals in the vertical direction.

The support jig for substrate heat treatment according to claim 1 or 2, wherein the support column is made of silicon carbide chemically vapor-deposited with a silicon carbide film, and the fixing member is made of quartz glass.

A heat treatment support jig that holds a plurality of heat-treated substrates in a vertical direction substantially horizontally at intervals, and has a groove for supporting the peripheral edge of the substrate, and is a cylindrical carbonization chemically deposited with a silicon carbide film. It is composed of a fixing member made of quartz glass having at least two or more cylindrical columns made of silicon and a convex connection portion that is fitted into a recess formed at the end of the column and connects and fixes the columns. Support jig for substrate heat treatment characterized by