JP3777964B2

JP3777964B2 - Substrate support for heat treatment

Info

Publication number: JP3777964B2
Application number: JP2000289825A
Authority: JP
Inventors: 健夫加藤
Original assignee: Sumco Corp
Current assignee: Sumco Corp
Priority date: 2000-09-25
Filing date: 2000-09-25
Publication date: 2006-05-24
Anticipated expiration: 2020-09-25
Also published as: JP2002100667A

Description

【０００１】
【発明の属する技術分野】
本発明は、シリコンウエーハ等の被処理基板を熱処理する際に用いられる熱処理用基板支持具に関するものである。
【０００２】
【従来の技術】
従来、シリコンウエーハを熱処理する際にそのシリコンウエーハを支持する熱処理用基板支持具として図６に示すように、円盤状の支持体１の上面側に立設した複数の支持ピン２でウエーハ３を水平に支持するものが知られている。また、図７に示すように、リング状の支持体６の内周縁部に形成された水平部６ａでウエーハ７を水平に支持する熱処理用基板支持具も知られている。
【０００３】
【発明が解決しようとする課題】
しかし、複数の支持ピン２でウエーハ３を水平に支持し、或いは水平部６ａでウエーハ７を水平に支持して熱処理を行った場合、支持体１及び６とウエーハ３及び７の熱膨張係数の相違により、支持ピン２とウエーハ３の間、或いは水平部６ａとウエーハ７の間に滑りが生じ、その滑りに起因するウエーハ３及び７の接触する部分の表面に傷が生じ、支持ピン２或いは水平部６ａにより支持された部分に、その傷に基づく結晶転位が生じる不具合があった。
本発明の目的は、被処理基板を支持する部分における被処理基板との滑りを最小限に抑えて、滑りに起因する傷に基づく結晶転位を抑制し得る熱処理用基板支持具を提供することにある。
【０００４】
【課題を解決するための手段】
請求項１に係る発明は、図１に示すように、耐熱性のある複数のワイヤ２１をたるませた状態で固定した熱処理用基板の支持具であって、被処理基板１３の直径より大きいリング部材２２を備え、複数のワイヤ２１がリング部材２２に固定され、被処理基板１３の下面周縁の少なくとも三カ所を複数のワイヤ２１上に載せて被処理基板１３を水平に支持するように構成されたことを特徴とする熱処理用基板支持具である。
この請求項１に係る熱処理用基板支持具では、被処理基板１３が熱処理の際に膨張して直径が拡大すると、たるませた状態で固定されたワイヤ２１はそれ自体が熱膨張することにより、或いはたるみを伸張させることにより、被処理基板１３の下面周縁が載せられた部分がその被処理基板１３の外周縁とともに移動し、被処理基板１３の下面周縁が載せられた部分とその被処理基板１３の外周縁の間の滑りを最小限に抑える。この結果、その滑りに起因する傷の発生は最小限に抑えられ、傷に基づく結晶転位の発生は従来より抑制される。
そして、リング部材２２を備えることにより複数のワイヤ２１を比較的容易にたるませた状態で固定することができる。
【０００５】
請求項２に係る発明は、請求項１に係る発明であって、図３に示すように、複数のワイヤ２１が互いに平行な一対のワイヤである熱処理用基板支持具である。
この請求項２に係る熱処理用基板支持具では、２本のワイヤを用いるのみであるので、ワイヤ２１の固定を比較的容易に行うことができる。
【０００６】
請求項３に係る発明は、請求項１に係る発明であって、図４に示すように、複数のワイヤ２１が放射状に設けられた熱処理用基板支持具である。
この請求項３に係る熱処理用基板支持具では、被処理基板１３の下面周縁のワイヤ２１上に載せる箇所又は数を比較的容易に調整することができ、図４に示すように３本のワイヤを放射状に設ければ被処理基板の下面周縁の三カ所をワイヤ２１上に載せることができる。
請求項４に係る発明は、請求項１に係る発明であって、図５に示すように、複数のワイヤ２１が格子状に設けられた熱処理用基板支持具である。
この請求項４に係る熱処理用基板支持具では、ワイヤ２１を直交させるだけなので、ワイヤ２１を固定する際の微妙な角度調整が不要になり、ワイヤ２１の固定が比較的容易に行うことができ、リング部材２２に複数のワイヤ２１を格子状に固定する場合にはそのリング部材２２の製作も比較的容易になる。
【０００７】
【発明の実施の形態】
次に本発明の実施の形態を図面に基づいて説明する。
図１に本発明の熱処理用基板支持具２０を備えた熱処理装置１０を示す。この熱処理装置１０は加熱炉１１を有し、加熱炉１１の一側部には搬入口１１ａが形成され、他側部には搬出口１１ｂが形成される。搬入側及び搬出側にはロボットアーム１２が配設され、このロボットアーム１２は未熱処理のシリコンウエーハ１３を炉内部に搬入し、熱処理済みのシリコンウエーハ１３を炉外部に搬出可能に構成される。加熱炉１１の内部は、例えば、石英（ＳｉＯ₂ ）、炭化ケイ素（ＳｉＣ）等の耐熱性の高い壁部材１４で囲繞されるとともに、その壁部材１４の外側にはヒータ素線１６ａを有する加熱ヒータ１６が配設され、その加熱ヒータ１６の外側は断熱材１７で囲繞される。加熱炉１１の下部には、上面側中央部に凹状収納部１８ａが形成された基台１８が配設される。その凹状収納部１８ａの底面中央部にはシリコンウエーハ１３を載置するための固定台１９が固定され、凹状収納部１８ａの底面中央部には第１摺動孔１８ｂが形成される。
【０００８】
固定台１９は、上述した凹状収納部１８ａの底面中央部に固定された円盤形状の台本体１９ａを備え、凹状収納部１８ａに形成された第１摺動孔１８ｂと上下方向に連通する第２摺動孔１９ｂが台本体１９ａの中央部に形成される。これらの第１及び第２摺動孔１８ｂ，１９ｂは、後述する昇降体２４の上下摺動が許容される孔径に形成される。台本体１９ａの上面側には、シリコンウエーハ１３の下面側中央部と対向する位置であって、上述した第２摺動孔１９ｂを中心として、先細形状に形成した複数本（例えば、３本）の各支持突起１９ｃを円周方向に対して等間隔に隔てて立設するとともに、各支持突起１９ｃを後述するリング部材２２の内径よりも内側に配列している。
【０００９】
本発明の熱処理用基板支持具２０は固定台１９の上方に設けられ、この実施の形態における熱処理用基板支持具２０は複数のワイヤ２１とリング部材２２と支持台２３とを備える。リング部材２２は、蓄熱性及び熱伝導性が良く、耐熱性の高い炭化ケイ素（ＳｉＣ）により形成され、その表面には化学的気相堆積（ＣＶＤ）法によりＳｉＣ膜が形成される。図２に示すように、リング部材２２は、被処理基板であるシリコンウエーハ１３の直径よりも大きな内径を有し、この実施の形態ではシリコンウエーハの直径をＤとしたとき、１．０５×Ｄから１．４×Ｄの間の大きさの内径ｄを有するリング形状に形成される。このリング部材２２には、中央を中心とした１２０度毎の３カ所に厚さ方向に貫通して孔部２２ｂ（図１）が形成される。
【００１０】
図２及び図３に示すように、複数のワイヤ２１はこのリング部材２２に固定され、この実施の形態における複数のワイヤ２１は互いに平行な一対のワイヤ２１から構成される。ワイヤ２１は耐熱性を有するものであり、この例ではタングステン又はモリブデンからなるものが使用され、その直径は５０μｍ以上５ｍｍ以下、好ましくは２００μｍ以上１ｍｍ以下のものが用いられる。リング部材２２には水平方向に貫通してワイヤ用孔２２ｃが形成され、このワイヤ用孔２２ｃに連通する雌ねじ孔２２ｄが厚さ方向に形成される。ワイヤ２１の端部はワイヤ用孔２２ｃに挿通され、雌ねじ孔２２ｄに螺合された雄ねじ２５の先端によりワイヤ２１の端部はそのワイヤ用孔２２ｃに固定される。このようにワイヤ２１の端部を固定することにより複数のワイヤ２１はたるませた状態でリング部材２２に固定され、被処理基板であるシリコンウエーハ１３の下面周縁の四カ所をこの複数のワイヤ２１上に載せてシリコンウエーハ１３を水平に支持するように構成される。ワイヤのたるみ量は、シリコンウエーハ１３の下面周縁が載せられたワイヤ２１の水平方向に対する傾斜角度θが１〜４５度、好ましくは５〜２０度になるように調整され、その調整は雄ねじ２５によるワイヤ２１端部の固定位置を僅かにずらすことにより行われる。
【００１１】
図１に戻って、支持台２３は、円盤形状に形成された台本体２３ａと、上述したリング部材２２の孔部２２ｂと対向して台本体２３ａの上面側周縁部に立設された複数本の支持軸２３ｂとを備える。台本体２３ａには、前述した固定台１９の各支持突起１９ｃが遊通可能な孔部２３ｃが形成され、各支持軸２３ｂの上端部はリング部材２２の孔部２２ｂに下方から差込まれてその孔部２２ｂに係合し、各支持軸２３ｂによりリング部材２２は水平状態にかつ交換可能に支持される。
【００１２】
凹状収納部１８ａに形成された第１摺動孔１８ｂと台本体１９ａの下面中央部に形成された第２摺動孔１９ｂには、図示しない昇降装置により昇降する昇降体２４が挿通される。熱処理用基板支持具２０は昇降体２４の上端に取付けられ、昇降体２４が昇降装置により昇降することによりその昇降体２４とともに昇降するように構成される。具体的に、熱処理用基板支持具２０を構成する台本体２３ａの下面中央部に、筒状に形成した昇降体２４の上端部が固定され、台本体２３ａの下面中央部に形成した孔部２３ｄが昇降体２４と連通される。図示しない昇降装置としては、例えば、サーボモータ、エアシリンダ等が挙げられ、この昇降装置により昇降体２４を鉛直方向に上下摺動させて、熱処理用基板支持具２０が支持突起１９ｃの上端よりも下方に位置する降下位置と、加熱炉１１の中心部まで持上げられた二点鎖線で示す上昇位置とに熱処理用基板支持具２０を上下動可能に構成される。なお、図示しないが、昇降体２４は、例えば、窒素ガス等のプロセスガスをパージするためのガス供給装置に接続され、加熱炉１１の搬出側又は搬入側には、降下位置に昇降停止されたシリコンウエーハ１３に向けて冷却ガスを吐出するための噴射ノズル２６が配設される。
【００１３】
次に、上述したウエーハ熱処理装置１０によりシリコンウエーハ１３を熱処理するときの動作を説明する。先ず、熱処理開始時に於いて、図１に示すように、熱処理用基板支持具２０を降下位置に維持させた状態でロボットアーム１２により保持した未熱処理のシリコンウエーハ１３を加熱炉１１内部に搬入し、加熱炉１１に設置された固定台１９の各支持突起１９ｃ上にシリコンウエーハ１３を水平に載置する。その後加熱炉１１外部にロボットアーム１２を引出し、熱処理用基板支持具２０を垂直上昇させて、リング部材２２に固定された互いに平行な一対のワイヤ２１上にシリコンウエーハ１３の下面周縁を載せる。シリコンウエーハ１３の下面周縁の四カ所を一対のワイヤ２１上に載せた後、そのシリコンウエーハ１３を水平に支持させた状態で二点鎖線で示す上昇位置まで持上げる。同時に、筒状の昇降体２４から吐出されるプロセスガスを加熱炉１１内部にパージして、熱処理に応じたガス環境を形成した後、シリコンウエーハ１３を水平に支持した状態のまま加熱ヒータ１６により１０００℃以上に熱処理する。
【００１４】
シリコンウエーハ１３が加熱ヒータ１６により加熱されると、シリコンウエーハ１３はその熱により膨張して直径が僅かに拡大し、その外周縁は図２の実線矢印で示すように外方に向かって移動する。この時、ワイヤ２１は、ワイヤ自体が熱膨張することにより、或いはたるみを伸張させることにより、シリコンウエーハ１３の下面周縁が載せられた部分がシリコンウエーハ１３の外周縁とともに破線で示すように移動し、シリコンウエーハ１３の下面周縁が載せられた部分とそのシリコンウエーハ１３の外周縁の間の滑りを最小限に抑える。
【００１５】
シリコンウエーハ１３の熱処理が完了した後は、熱処理用基板支持具２０を垂直降下させ、リング部材２２に固定された一対のワイヤ２１により支持されたシリコンウエーハ１３を固定台１９の各支持突起１９ｃに再び載置し、固定台１９の各支持突起１９ｃよりも下方にリング部材２２を降下させた後、加熱炉１１内部にロボットアーム１２を挿入して、固定台１９の各支持突起１９ｃにより支持された熱処理済みのシリコンウエーハ１３をロボットアーム１２により保持し、その保持されたシリコンウエーハ１３を搬出するとき噴射ノズル２６から吐出される冷却ガスを吹き付けて冷却処理し、加熱炉１１外部にロボットアーム１２を引出して熱処理済みのシリコンウエーハ１３を次の処理工程に移送する。
【００１６】
なお、上述した実施の形態では、複数本の各支持軸２３ｂ上部に設けられたリング部材２２に複数のワイヤ２１を固定したが、被処理基板であるシリコンウエーハ１３の下面周縁を載せて水平に支持可能である限り、リング部材を用いることなく、複数のワイヤを各支持軸２３ｂの上部にたるませた状態で直接架設しても良い。
【００１７】
また、上述した実施の形態では、互いに平行な一対のワイヤ２１から構成された複数のワイヤ２１を説明したが、複数のワイヤ２１は図４に示すように放射状に設けても良く、図５に示すように格子状に設けてもよい。複数のワイヤ２１を放射状に設ければ、被処理基板の下面周縁のワイヤ２１上に載せる箇所又は数を比較的容易に調整することができ、図４に示すように３本のワイヤを放射状に設ければ被処理基板の下面周縁の三カ所をワイヤ２１上に載せることができる。一方、複数のワイヤ２１を直交させて格子状に設ければ、ワイヤ２１を固定する際の微妙な角度調整が不要になり、ワイヤ２１の固定が比較的容易に行うことができ、リング部材に複数のワイヤを格子状に固定する場合にはそのリング部材の製作も比較的容易になる。
更に、上述した実施の形態では、被処理基板としてシリコンウェーハを挙げたが、被処理基板は、ＧａＰウェーハ，ＧａＡｓウェーハ等でもよく、ウェーハの外径は８インチ及び６インチに限らずその他の外径を有するものでもよい。
【００１８】
【発明の効果】
以上述べたように、本発明によれば、耐熱性のある複数のワイヤをたるませた状態で固定し、被処理基板の下面周縁の少なくとも三カ所を複数のワイヤ上に載せて被処理基板を水平に支持するように構成したので、被処理基板が熱処理の際に膨張して直径が拡大すると、たるませた状態で固定されたワイヤはそれ自体が熱膨張することにより、或いはたるみを伸張させることにより、被処理基板の下面周縁が載せられた部分がその被処理基板の外周縁とともに移動し、被処理基板の下面周縁が載せられた部分とその被処理基板の外周縁の間の滑りを最小限に抑える。この結果、その滑りに起因する傷の発生も最小限に抑えられ、傷に基づく結晶転位の発生を従来より抑制することができる。
【００１９】
また、被処理基板の直径より大きいリング部材を更に備え、複数のワイヤをリング部材に固定すれば、複数のワイヤを比較的容易にたるませた状態で固定することができ、互いに平行な一対のワイヤを用いればその固定を比較的容易に行うことができる。一方、複数のワイヤを放射状に設ければ、被処理基板の下面周縁のワイヤ上に載せる箇所又は数を比較的容易に調整することができ、複数のワイヤを格子状に設ければ、ワイヤを直交させるだけなので、ワイヤを固定する際の微妙な角度調整が不要になり、ワイヤの固定を容易に行うことが可能になる。
【図面の簡単な説明】
【図１】本発明の基板支持具を含む熱処理装置の構成を示す縦断面図。
【図２】図１のＡ部拡大断面図。
【図３】リング部材に平行な一対のワイヤが固定された基板支持具の平面図。
【図４】リング部材に複数のワイヤが放射状に固定された基板支持具の平面図。
【図５】リング部材に複数のワイヤが格子状に固定された基板支持具の平面図。
【図６】 (a)複数の支持ピンで被処理基板を支持する従来の基板支持具の平面図。
(b)その従来の基板支持具を示す(a)のＢ−Ｂ線断面図。
【図７】 (a)水平部で被処理基板を支持する従来の基板支持具の平面図。
(b)その従来の基板支持具の縦断面図。
【符号の説明】
１３シリコンウエーハ（被処理基板）
２０熱処理用基板支持具
２１ワイヤ
２２リング部材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate support for heat treatment used when heat treating a substrate to be processed such as a silicon wafer.
[0002]
[Prior art]
Conventionally, as shown in FIG. 6 as a substrate support for heat treatment for supporting a silicon wafer when heat-treating the silicon wafer, the wafer 3 is formed by a plurality of support pins 2 erected on the upper surface side of a disk-shaped support 1. What supports horizontally is known. Further, as shown in FIG. 7, a heat treatment substrate support is also known in which a wafer 7 is horizontally supported by a horizontal portion 6a formed on the inner peripheral edge of a ring-shaped support 6.
[0003]
[Problems to be solved by the invention]
However, when the wafer 3 is horizontally supported by the plurality of support pins 2 or the wafer 7 is horizontally supported by the horizontal portion 6a and the heat treatment is performed, the thermal expansion coefficients of the supports 1 and 6 and the wafers 3 and 7 are increased. Due to the difference, a slip occurs between the support pin 2 and the wafer 3 or between the horizontal portion 6a and the wafer 7, and the surface of the portion where the wafers 3 and 7 contact due to the slip is damaged, and the support pin 2 or There was a problem that crystal dislocation based on the scratches occurred in the portion supported by the horizontal portion 6a.
An object of the present invention is to provide a substrate support for heat treatment capable of suppressing crystal dislocation based on scratches caused by slip while minimizing slippage with a substrate to be processed in a portion supporting the substrate to be processed. is there.
[0004]
[Means for Solving the Problems]
As shown in FIG. 1, the invention according to claim 1 is a support for a heat treatment substrate in which a plurality of heat resistant wires 21 are fixed in a slack state, and is a ring larger than the diameter of the substrate 13 to be processed. A member 22 is provided, and a plurality of wires 21 are fixed to the ring member 22, and are configured to support at least three portions of the lower surface periphery of the substrate to be processed 13 on the plurality of wires 21 to horizontally support the substrate to be processed 13. A substrate support for heat treatment characterized by the above.
In the substrate support for heat treatment according to claim 1, when the substrate to be processed 13 expands during the heat treatment and expands in diameter, the wire 21 fixed in a slack state is thermally expanded by itself, Alternatively, by extending the slack, the portion on which the lower surface periphery of the substrate to be processed 13 is moved together with the outer periphery of the substrate to be processed 13, and the portion on which the lower surface periphery of the substrate to be processed 13 is mounted and the substrate to be processed Minimize slippage between the 13 outer edges. As a result, the occurrence of scratches due to the slip is minimized, and the occurrence of crystal dislocations based on the scratches is suppressed as compared with the conventional case.
And by providing the ring member 22, the some wire 21 can be fixed in the state which slackened comparatively easily.
[0005]
The invention according to claim 2 is the substrate support for heat treatment according to claim 1 , wherein the plurality of wires 21 are a pair of parallel wires as shown in FIG. 3.
In the substrate support for heat treatment according to the second aspect , since only two wires are used, the wire 21 can be fixed relatively easily.
[0006]
The invention according to claim 3 is the invention according to claim 1 , which is a substrate support for heat treatment in which a plurality of wires 21 are provided radially as shown in FIG.
In the substrate support tool for heat treatment according to the third aspect , the place or the number of the substrates to be placed on the wire 21 around the lower surface of the substrate to be processed 13 can be adjusted relatively easily. As shown in FIG. Can be placed on the wire 21 at the periphery of the lower surface of the substrate to be processed.
The invention according to claim 4 is the invention according to claim 1 , which is a substrate support for heat treatment in which a plurality of wires 21 are provided in a lattice shape as shown in FIG.
In the substrate support tool for heat treatment according to the fourth aspect , since the wires 21 are merely orthogonal, there is no need for fine angle adjustment when the wires 21 are fixed, and the wires 21 can be fixed relatively easily. When the plurality of wires 21 are fixed to the ring member 22 in a lattice shape, the production of the ring member 22 is relatively easy.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a heat treatment apparatus 10 provided with a heat treatment substrate support 20 of the present invention. This heat treatment apparatus 10 has a heating furnace 11, a carry-in port 11 a is formed on one side of the heating furnace 11, and a carry-out port 11 b is formed on the other side. A robot arm 12 is disposed on the carry-in side and the carry-out side, and the robot arm 12 is configured so that an unheat-treated silicon wafer 13 can be carried into the furnace and the heat-treated silicon wafer 13 can be carried out of the furnace. The inside of the heating furnace 11 is surrounded by a highly heat-resistant wall member 14 such as quartz (SiO ₂ ), silicon carbide (SiC), and the like, and a heater having a heater wire 16 a outside the wall member 14. A heater 16 is provided, and the outside of the heater 16 is surrounded by a heat insulating material 17. At the lower part of the heating furnace 11, a base 18 having a concave storage portion 18a formed at the center on the upper surface side is disposed. A fixing base 19 for mounting the silicon wafer 13 is fixed to the center of the bottom surface of the concave storage portion 18a, and a first sliding hole 18b is formed in the center of the bottom surface of the concave storage portion 18a.
[0008]
The fixed base 19 includes a disk-shaped base body 19a fixed to the center of the bottom surface of the concave storage portion 18a described above, and is connected to the first sliding hole 18b formed in the concave storage portion 18a in the vertical direction. A sliding hole 19b is formed in the center of the base body 19a. These first and second sliding holes 18b and 19b are formed to have a hole diameter that allows the vertical movement of the lifting body 24 described later to be allowed. A plurality of (for example, three) tapers are formed on the upper surface side of the base body 19a so as to be opposed to the central portion on the lower surface side of the silicon wafer 13 and have a tapered shape with the second sliding hole 19b as a center. The support protrusions 19c are erected at equal intervals in the circumferential direction, and the support protrusions 19c are arranged on the inner side of the inner diameter of a ring member 22 to be described later.
[0009]
The heat treatment substrate support 20 of the present invention is provided above the fixed base 19, and the heat treatment substrate support 20 in this embodiment includes a plurality of wires 21, a ring member 22 and a support 23. The ring member 22 is formed of silicon carbide (SiC) having good heat storage and thermal conductivity and high heat resistance, and an SiC film is formed on the surface thereof by chemical vapor deposition (CVD). As shown in FIG. 2, the ring member 22 has an inner diameter larger than the diameter of the silicon wafer 13 which is a substrate to be processed. In this embodiment, when the diameter of the silicon wafer is D, 1.05 × D To 1.4 × D in the form of a ring having an inner diameter d. The ring member 22 has holes 22b (FIG. 1) penetrating in the thickness direction at three locations every 120 degrees with the center at the center.
[0010]
As shown in FIGS. 2 and 3, the plurality of wires 21 are fixed to the ring member 22, and the plurality of wires 21 in this embodiment are constituted by a pair of wires 21 parallel to each other. The wire 21 has heat resistance. In this example, a wire made of tungsten or molybdenum is used, and a diameter of 50 to 5 mm, preferably 200 to 1 mm is used. The ring member 22 is formed with a wire hole 22c penetrating in the horizontal direction, and a female screw hole 22d communicating with the wire hole 22c is formed in the thickness direction. The end of the wire 21 is inserted into the wire hole 22c, and the end of the wire 21 is fixed to the wire hole 22c by the tip of the male screw 25 screwed into the female screw hole 22d. By fixing the end portions of the wires 21 in this way, the plurality of wires 21 are fixed to the ring member 22 in a slack state, and the plurality of wires 21 are arranged at four locations on the peripheral edge of the lower surface of the silicon wafer 13 which is the substrate to be processed. The silicon wafer 13 is mounted on the top and supported horizontally. The amount of slackness of the wire is adjusted so that the inclination angle θ with respect to the horizontal direction of the wire 21 on which the lower peripheral edge of the silicon wafer 13 is placed is 1 to 45 degrees, preferably 5 to 20 degrees. This is done by slightly shifting the fixing position of the end of the wire 21.
[0011]
Returning to FIG. 1, the support base 23 includes a plurality of base bodies 23 a formed in a disk shape, and a plurality of support bases 23, which are opposed to the above-described hole 22 b of the ring member 22 and which are provided on the upper peripheral edge of the base body 23 a. The support shaft 23b is provided. The base body 23 a is formed with holes 23 c through which the support protrusions 19 c of the fixed base 19 described above can freely pass. The upper ends of the support shafts 23 b are inserted into the hole 22 b of the ring member 22 from below. The ring member 22 is supported in a horizontal state and exchangeable by the support shafts 23b by engaging with the hole portions 22b.
[0012]
An elevating body 24 that is moved up and down by an elevating device (not shown) is inserted through the first sliding hole 18b formed in the concave storage portion 18a and the second sliding hole 19b formed in the center of the lower surface of the base body 19a. The heat treatment substrate support 20 is attached to the upper end of the elevating body 24 and is configured to move up and down together with the elevating body 24 when the elevating body 24 is raised and lowered by the elevating device. Specifically, the upper end portion of the lifting body 24 formed in a cylindrical shape is fixed to the central portion of the lower surface of the base body 23a constituting the heat treatment substrate support 20, and the hole 23d formed in the central portion of the lower surface of the base body 23a. Is communicated with the lifting body 24. As an elevating device (not shown), for example, a servo motor, an air cylinder, and the like can be cited. The elevating body 24 is vertically slid by the elevating device so that the heat treatment substrate support 20 is more than the upper end of the support protrusion 19c. The heat treatment substrate support 20 is configured to be movable up and down at a lowering position located below and a rising position indicated by a two-dot chain line lifted to the center of the heating furnace 11. Although not shown, the elevating body 24 is connected to a gas supply device for purging process gas such as nitrogen gas, for example, and is lifted and stopped at the lowered position on the carry-out side or the carry-in side of the heating furnace 11. An injection nozzle 26 for discharging a cooling gas toward the silicon wafer 13 is provided.
[0013]
Next, the operation when the silicon wafer 13 is heat treated by the wafer heat treatment apparatus 10 described above will be described. First, at the start of the heat treatment, as shown in FIG. 1, the unheated silicon wafer 13 held by the robot arm 12 is carried into the heating furnace 11 with the substrate support 20 for heat treatment maintained in the lowered position. The silicon wafer 13 is horizontally placed on each support protrusion 19c of the fixed base 19 installed in the heating furnace 11. Thereafter, the robot arm 12 is pulled out of the heating furnace 11, the heat treatment substrate support 20 is vertically raised, and the lower surface periphery of the silicon wafer 13 is placed on a pair of parallel wires 21 fixed to the ring member 22. After placing the four places on the peripheral edge of the lower surface of the silicon wafer 13 on the pair of wires 21, the silicon wafer 13 is lifted up to a rising position indicated by a two-dot chain line in a state where the silicon wafer 13 is horizontally supported. At the same time, the process gas discharged from the cylindrical lifting body 24 is purged into the heating furnace 11 to form a gas environment corresponding to the heat treatment, and then the heater 16 is used while the silicon wafer 13 is horizontally supported. Heat treatment at 1000 ° C. or higher.
[0014]
When the silicon wafer 13 is heated by the heater 16, the silicon wafer 13 expands due to the heat and slightly expands in diameter, and its outer peripheral edge moves outward as indicated by solid line arrows in FIG. . At this time, the wire 21 moves as shown by a broken line together with the outer peripheral edge of the silicon wafer 13 by the thermal expansion of the wire itself or by extending the slack, so that the portion on which the lower peripheral edge of the silicon wafer 13 is mounted is moved. Slip between the portion of the silicon wafer 13 on which the lower peripheral edge is placed and the outer peripheral edge of the silicon wafer 13 is minimized.
[0015]
After the heat treatment of the silicon wafer 13 is completed, the substrate support 20 for heat treatment is vertically lowered, and the silicon wafer 13 supported by the pair of wires 21 fixed to the ring member 22 is applied to each support protrusion 19c of the fixing base 19. After placing again and lowering the ring member 22 below the support protrusions 19c of the fixed base 19, the robot arm 12 is inserted into the heating furnace 11 and supported by the support protrusions 19c of the fixed base 19. The heat-treated silicon wafer 13 is held by the robot arm 12, and when the held silicon wafer 13 is unloaded, the cooling gas discharged from the spray nozzle 26 is blown to cool the robot wafer 12. And the heat-treated silicon wafer 13 is transferred to the next processing step.
[0016]
In the above-described embodiment, the plurality of wires 21 are fixed to the ring members 22 provided on the plurality of support shafts 23b. However, the peripheral edge of the lower surface of the silicon wafer 13 as the substrate to be processed is placed horizontally. As long as it can be supported, a plurality of wires may be directly installed in a state where they are slackened on the upper part of each support shaft 23b without using a ring member.
[0017]
In the above-described embodiment, the plurality of wires 21 constituted by a pair of wires 21 parallel to each other have been described. However, the plurality of wires 21 may be provided radially as shown in FIG. As shown, it may be provided in a lattice shape. If a plurality of wires 21 are provided in a radial pattern, the number or number of places on the wire 21 on the peripheral edge of the lower surface of the substrate to be processed can be adjusted relatively easily. As shown in FIG. If provided, three places on the periphery of the lower surface of the substrate to be processed can be placed on the wire 21. On the other hand, if a plurality of wires 21 are arranged orthogonally and arranged in a lattice shape, a fine angle adjustment when fixing the wires 21 is not required, and the wires 21 can be fixed relatively easily. When a plurality of wires are fixed in a lattice shape, the ring member can be relatively easily manufactured.
Furthermore, in the above-described embodiment, a silicon wafer is used as the substrate to be processed. However, the substrate to be processed may be a GaP wafer, a GaAs wafer, or the like, and the outer diameter of the wafer is not limited to 8 inches and 6 inches. It may have a diameter.
[0018]
【The invention's effect】
As described above, according to the present invention, a plurality of heat-resistant wires are fixed in a slack state, and at least three portions of the lower surface periphery of the substrate to be processed are placed on the plurality of wires to mount the substrate to be processed. Since the substrate is supported horizontally, when the substrate to be processed expands during the heat treatment and expands in diameter, the wire fixed in a slack state is thermally expanded by itself or stretches the slack. As a result, the portion of the substrate to be processed placed on the lower peripheral edge moves together with the outer peripheral edge of the substrate to be processed, and the slip between the portion of the substrate to be processed and the lower peripheral edge of the substrate to be processed and the outer peripheral edge of the substrate to be processed can Minimize. As a result, the occurrence of scratches due to the slip can be suppressed to the minimum, and the occurrence of crystal dislocations based on the scratches can be suppressed as compared with the prior art.
[0019]
In addition, if a ring member larger than the diameter of the substrate to be processed is further provided and a plurality of wires are fixed to the ring member, the plurality of wires can be fixed relatively easily, and a pair of parallel wires can be fixed. If a wire is used, it can be fixed relatively easily. On the other hand, if a plurality of wires are provided in a radial pattern, the number or number of places placed on the wire on the peripheral edge of the lower surface of the substrate to be processed can be adjusted relatively easily. Since it is only made orthogonal, the delicate angle adjustment at the time of fixing a wire becomes unnecessary, and it becomes possible to fix a wire easily.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a configuration of a heat treatment apparatus including a substrate support according to the present invention.
FIG. 2 is an enlarged cross-sectional view of a part A in FIG.
FIG. 3 is a plan view of a substrate support in which a pair of wires parallel to a ring member is fixed.
FIG. 4 is a plan view of a substrate support in which a plurality of wires are radially fixed to a ring member.
FIG. 5 is a plan view of a substrate support in which a plurality of wires are fixed to a ring member in a lattice shape.
FIG. 6A is a plan view of a conventional substrate support that supports a substrate to be processed with a plurality of support pins.
(b) The BB sectional drawing of (a) which shows the conventional board | substrate support tool.
7A is a plan view of a conventional substrate support that supports a substrate to be processed in a horizontal portion. FIG.
(b) The longitudinal cross-sectional view of the conventional board | substrate support tool.
[Explanation of symbols]
13 Silicon wafer (substrate to be processed)
20 Heat Treatment Substrate Support 21 Wire 22 Ring Member

Claims

A support for a heat treatment substrate in which a plurality of heat resistant wires (21) are fixed in a slack state,
Provided with a ring member (22) larger than the diameter of the substrate to be processed (13) ,
The plurality of wires (21) are fixed to the ring member (22) ,
For heat treatment, the substrate (13) is configured to horizontally support the substrate to be processed (13) by placing at least three places on the periphery of the lower surface of the substrate to be processed (13) on the plurality of wires (21). Substrate support.

The substrate support for heat treatment according to claim 1, wherein the plurality of wires (21) are a pair of parallel wires.

The substrate support for heat treatment according to claim 1, wherein a plurality of wires (21) are provided radially.

The substrate support for heat treatment according to claim 1, wherein a plurality of wires (21) are provided in a lattice shape.