JP2004143002A - Apparatus and method for controlling silicon melt convection - Google Patents

Apparatus and method for controlling silicon melt convection Download PDF

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JP2004143002A
JP2004143002A JP2002311100A JP2002311100A JP2004143002A JP 2004143002 A JP2004143002 A JP 2004143002A JP 2002311100 A JP2002311100 A JP 2002311100A JP 2002311100 A JP2002311100 A JP 2002311100A JP 2004143002 A JP2004143002 A JP 2004143002A
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heat
silicon melt
ingot
silicon
melt
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Shinrin Fu
符　森林
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Sumco Corp
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Sumitomo Mitsubishi Silicon Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To relatively easily produce an indefective silicon single crystal ingot even when the ingot has a large diameter. <P>SOLUTION: A silicon melt 12 is held in a quartz crucible 13 set in a chamber 11, and a main heater 18 is constituted in a manner that it surrounds the crucible 13 and heat the silicon melt 12. A heat source 43 that radiates heat toward the center of the lower surface of an ingot 25 in the silicon melt 12 below the solid/liquid interface 26 between the ingot 25 pulled up from the melt 12 and the silicon melt 12 is provided. The solid-liquid interface 26 becomes upward convex by the action of the heat generated from the source 43. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、石英るつぼに貯留されたシリコン融液からシリコン単結晶のインゴットを引上げるときに上記シリコン融液の対流を制御する装置と、その制御方法に関するものである。
【０００２】
【従来の技術】
従来、シリコン単結晶の製造方法として、シリコン単結晶のインゴットをチョクラルスキー法（以下、ＣＺ法という）により引上げる方法が知られている。このＣＺ法は、石英るつぼに貯留されたシリコン融液に種結晶を接触させ、石英るつぼ及び種結晶を回転させながら種結晶を引上げることにより、円柱状のシリコン単結晶のインゴットを製造する方法である。
一方、半導体集積回路を製造する工程において、歩留りを低下させる原因として酸化誘起積層欠陥（Ｏｘｉｄａｔｉｏｎ−ｉｎｄｕｃｅｄ　Ｓｔａｃｋｉｎｇ　Ｆａｕｌｔ、以下、ＯＳＦという。）の核となる酸素析出物の微小欠陥や、結晶に起因したパーティクル（Ｃｒｙｓｔａｌ　Ｏｒｉｇｉｎａｔｅｄ　Ｐａｒｔｉｃｌｅ、以下、ＣＯＰという。）や、或いは侵入型転位（Ｉｎｔｅｒｓｔｉｔｉａｌ−ｔｙｐｅ　Ｌａｒｇｅ　Ｄｉｓｌｏｃａｔｉｏｎ、以下、Ｌ／Ｄという。）の存在が挙げられている。ＯＳＦは、結晶成長時にその核となる微小欠陥が導入され、半導体デバイスを製造する際の熱酸化工程等で顕在化し、作製したデバイスのリーク電流の増加等の不良原因になる。またＣＯＰは、鏡面研磨後のシリコンウェーハをアンモニアと過酸化水素の混合液で洗浄したときにウェーハ表面に出現する結晶に起因したピットである。このウェーハをパーティクルカウンタで測定すると、このピットも本来のパーティクルとともに光散乱欠陥として検出される。
【０００３】
このＣＯＰは電気的特性、例えば酸化膜の経時絶縁破壊特性（Ｔｉｍｅ　Ｄｅｐｅｎｄｅｎｔｄｉｅｌｅｃｔｒｉｃ　Ｂｒｅａｋｄｏｗｎ、ＴＤＤＢ）、酸化膜耐圧特性（Ｔｉｍｅ　Ｚｅｒｏ　Ｄｉｅｌｅｃｔｒｉｃ　Ｂｒｅａｋｄｏｗｎ、ＴＺＤＢ）等を劣化させる原因となる。またＣＯＰがウェーハ表面に存在するとデバイスの配線工程において段差を生じ、断線の原因となり得る。そして素子分離部分においてもリーク等の原因となり、製品の歩留りを低くする。更にＬ／Ｄは、転位クラスタとも呼ばれたり、或いはこの欠陥を生じたシリコンウェーハをフッ酸を主成分とする選択エッチング液に浸漬するとピットを生じることから転位ピットとも呼ばれる。このＬ／Ｄも、電気的特性、例えばリーク特性、アイソレーション特性等を劣化させる原因となる。この結果、半導体集積回路を製造するために用いられるシリコンウェーハからＯＳＦ、ＣＯＰ及びＬ／Ｄを減少させることが必要となっている。
【０００４】
このＯＳＦ、ＣＯＰ及びＬ／Ｄを有しない無欠陥のシリコンウェーハを切出すためのシリコン単結晶インゴットの製造方法が米国特許番号６，０４５，６１０号に対応する特開平１１−１３９３号公報に開示されている。一般に、シリコン単結晶のインゴットを速い速度で引上げると、インゴット内部に空孔型点欠陥の凝集体が支配的に存在する領域［Ｖ］が形成され、インゴットを遅い速度で引上げると、インゴット内部に格子間シリコン型点欠陥の凝集体が支配的に存在する領域［Ｉ］が形成される。このため上記製造方法では、インゴットを最適な引上げ速度で引上げることにより、上記点欠陥の凝集体が存在しないパーフェクト領域［Ｐ］からなるシリコン単結晶のインゴットを製造できるようになっている。
【０００５】
一方、ＣＺ法によりシリコン融液からシリコン単結晶のインゴットを引上げるときに、インゴットとシリコン融液との固液界面の形状を考慮して無欠陥結晶を製造する方法が開示されている（例えば、特許文献１参照）。この無欠陥結晶を製造する方法では、上記固液界面の形状の調整が、インゴット下面の中心における固液界面の高さを調整することによって行われ、インゴット下面の周縁の温度分布の調整が、インゴット外周部の引上げ方向の温度勾配を調整することによって行われる。また上記インゴット下面の中心における固液界面の高さがシリコン融液表面より１０ｍｍ以上高くなるように、インゴット下面の中心における固液界面の高さの調整が、シリコン融液に対して印加される磁場の強度の調整、シリコン融液を貯留する石英るつぼの単位時間当りの回転速度の調整、及びインゴットの単位時間当りの回転速度の調整からなる群から選ばれた１種又は２種以上の調整によって行われる。上記磁場は、石英るつぼの外周面から所定の間隔をあけて設けられたソレノイドに所定の電流を流すことにより発生し、シリコン融液に印加される。
【０００６】
このように構成された無欠陥結晶を製造する方法では、シリコン融液からシリコン単結晶のインゴットを引上げるときに、上記固液界面の形状と引上げ中のインゴット下部周縁の温度分布との関係を適切に調整することによって、無欠陥のシリコン単結晶インゴットを安定かつ再現性よく製造することができる。即ち、インゴットの引上げ方向及び半径の面方向のいずれにおいても、広い範囲にわたって無欠陥領域を有するインゴットを安定かつ再現性良く製造することができる。この結果、インゴットをスライスして得られる無欠陥ウェーハの枚数が多くなるので、歩留まりを向上できるとともに、大口径のインゴットを引上げた後にこの大口径のインゴットをスライスして得られる大口径のウェーハは全面が無欠陥となる。
【０００７】
【特許文献１】
米国特許第６，０４５，６１０号明細書に対応する特開平１１−１３９３号公報
【０００８】
【発明が解決しようとする課題】
しかし、上記従来の特許文献１に示されたシリコン単結晶インゴットの製造方法では、シリコン単結晶のインゴットとシリコン融液との固液界面近傍での鉛直方向の温度勾配が均一になるように制御する必要があり、この制御はシリコン融液の残量の変化や対流の変化による影響を受けるため、インゴットの直胴部全長にわたって、無欠陥のシリコン単結晶を製造することは困難であった。
また、上記従来の特許文献１に示された無欠陥結晶を製造する方法では、シリコン単結晶のインゴットが大口径化するに従って、磁場を発生するソレノイドを大型化する必要があるけれども、このソレノイドの大型化の割合はインゴットの大口径化の割合より飛躍的に大きいため、インゴットの大口径化に伴ってソレノイドの製作が技術及び資金の両面で困難になるおそれがある。
本発明の目的は、シリコン単結晶のインゴットが大口径化しても、無欠陥のシリコン単結晶のインゴットを比較的容易に製造できる、シリコン融液対流制御装置及びその制御方法を提供することにある。
【０００９】
【課題を解決するための手段】
請求項１に係る発明は、図１及び図４に示すように、チャンバ１１内に設けられシリコン融液１２が貯留された石英るつぼ１３と、石英るつぼ１３の外周面を包囲しシリコン融液１２を加熱する主ヒータ１８とを備えたシリコン単結晶引上げ装置の改良である。
その特徴ある構成は、シリコン融液１２から引上げられるインゴット２５とシリコン融液１２との固液界面２６より下方のシリコン融液１２中でインゴット２５下面の中心に向って放熱する熱源４３が設けられ、熱源４３からの放熱により固液界面２６が上凸状となるように構成されたところにある。
【００１０】
請求項７に係る発明は、図１及び図４に示すように、チャンバ１１内に設けられた石英るつぼ１３にインゴット２５を引上げ可能なシリコン融液１２を貯留し、インゴット２５内が格子間シリコン型点欠陥の凝集体及び空孔型点欠陥の凝集体の存在しないパーフェクト領域となる引上げ速度でインゴット２５を引上げるシリコン単結晶引上げ方法の改良である。
その特徴ある構成は、インゴット２５とシリコン融液１２との固液界面２６より下方のシリコン融液１２中で熱源４３がインゴット２５下面の中心に向って放熱し、固液界面２６が上凸状となるように熱源４３を制御するところにある。
【００１１】
この請求項１に記載されたシリコン融液対流制御装置又は請求項７に記載されたシリコン融液対流制御方法では、熱源４３から固液界面２６の中心に向って放熱しながら、シリコン融液１２からインゴット２５を引上げると、石英るつぼ１３中心のシリコン融液１２に上昇する対流が発生するため、この対流により固液界面２６が上凸状になる。この結果、固液界面２６の中心がシリコン融液１２表面の延長面より上方に位置するため、固液界面２６の中心近傍の鉛直方向の温度勾配が大きくなり、固液界面２６の中心近傍の鉛直方向の温度勾配と、固液界面２６の周縁近傍の鉛直方向の温度勾配との差が小さくなる。
【００１２】
【発明の実施の形態】
次に本発明の第１の実施の形態を図面に基づいて説明する。
図４に示すように、シリコン単結晶引上げ装置１０のチャンバ１１内には、シリコン融液１２を貯留する石英るつぼ１３が設けられ、この石英るつぼ１３の外周面は黒鉛サセプタ１４により被覆される。石英るつぼ１３の下面は上記黒鉛サセプタ１４を介して支軸１６の上端に固定され、この支軸１６の下部はるつぼ駆動手段１７に接続される。るつぼ駆動手段１７は図示しないが石英るつぼ１３を回転させる第１回転用モータと、石英るつぼ１３を昇降させる昇降用モータとを有し、これらのモータにより石英るつぼ１３が所定の方向に回転し得るとともに、上下方向に移動可能となっている。石英るつぼ１３の外周面は石英るつぼ１３から所定の間隔をあけて主ヒータ１８により包囲され、この主ヒータ１８は保温筒１９により包囲される。また主ヒータ１８には主ヒータ用電源（図示せず）が電気的に接続される。
【００１３】
またチャンバ１１の上端には円筒状のケーシング２１が接続される。このケーシング２１には引上げ手段２２が設けられる。引上げ手段２２はケーシング２１の上端部に水平状態で旋回可能に設けられた引上げヘッド（図示せず）と、このヘッドを回転させる第２回転用モータ（図示せず）と、ヘッドから石英るつぼ１３の回転中心に向って垂下されたワイヤケーブル２３と、上記ヘッド内に設けられワイヤケーブル２３を巻取り又は繰出す引上げ用モータ（図示せず）とを有する。ワイヤケーブル２３の下端にはシリコン融液１２に浸してシリコン単結晶のインゴット２５を引上げるための種結晶２４が取付けられる。
【００１４】
更にチャンバ１１には引上げ中のインゴット外周面側に不活性ガスを供給しかつ不活性ガスをチャンバ１１のるつぼ内周面側から排出するガス給排手段２８が接続される。ガス給排手段２８は一端がケーシング２１の周壁に接続され他端が上記不活性ガスを貯留するタンク（図示せず）に接続された供給パイプ２９と、一端がチャンバ１１の下壁に接続され他端が真空ポンプ（図示せず）に接続された排出パイプ３０とを有する。供給パイプ２９及び排出パイプ３０にはこれらのパイプ２９，３０を流れる不活性ガスの流量を調整する第１及び第２流量調整弁３１，３２がそれぞれ設けられる。
【００１５】
一方、インゴット２５の外周面と石英るつぼ１３の内周面との間にはインゴット２５の外周面を包囲する熱遮蔽部材３６が設けられる。この熱遮蔽部材３６は円筒状に形成され主ヒータ１８からの輻射熱を遮る筒部３７と、この筒部３７の上縁に連設され外方に略水平方向に張り出すフランジ部３８と、筒部３７の下部に筒部３７内方に膨出するように設けられた膨出部４１とを有する。上記フランジ部３８を保温筒１９上に載置することにより、筒部３７の下縁がシリコン融液１２表面から所定の距離だけ上方に位置するように、熱遮蔽部材３６がチャンバ１１内に固定される。この筒部３７及び膨出部４１は黒鉛により、或いは表面にＳｉＣがコーティングされた黒鉛等により形成される。また膨出部４１の内部には膨出部用断熱部材４２が充填され、この膨出部用断熱部材４２はカーボンフェルト、即ちカーボンファイバの不織布により形成される。
【００１６】
一方、図１〜図４に示すように、インゴット２５とシリコン融液１２との固液界面２６より下方のシリコン融液１２中には、インゴット２５下面の中心に向って放熱する熱源４３が設けられる。この熱源４３は、熱遮蔽部材３６下端及びシリコン融液１２表面間に設けられた補助ヒータ４４と、補助ヒータ４４の発した熱を受けこの熱をシリコン融液１２中のインゴット２５下方に導き更にインゴット２５下面の中心に向って放散する熱伝導体４６と、補助ヒータ４４及び熱伝導体４６の周面を被覆する石英管４７と、熱伝導体４６及び石英管４７間に充填された熱源用断熱部材４８（図３）とを有する。
【００１７】
補助ヒータ４４は小型のカーボンヒータにより構成される。この補助ヒータ４４には、チャンバ１１外から配索されかつ膨出部４１を貫通する一対のカーボン電極４９，４９の一端が電気的に接続され、一対のカーボン電極４９，４９の他端はチャンバ１１外に設けられた補助ヒータ用電源（図示せず）に電気的に接続される。熱伝導体４６は、補助ヒータ４４に対向して設けられた受熱部４６ａと、シリコン融液１２中でインゴット２５下面の中心に対向して設けられた放熱部４６ｂと、受熱部４６ａ及び放熱部４６ｂを連結し受熱部４６ａの受けた熱を放熱部４６ｂに導く伝導部４６ｃとからなる。上記受熱部４６ａ、放熱部４６ｂ及び伝導部４６ｃはソリッドカーボンにより一体的に形成される。
【００１８】
補助ヒータ４４には、受熱部４６ａを１４５０〜２０００℃、好ましくは１６００〜１８５０℃の範囲に加熱可能な電力が補助ヒータ用電源から供給されに構成され、これにより放熱部４６ｂはこの放熱部４６ｂ上面に対向するシリコン融液１２を１４３０〜１９００℃、好ましくは１５００〜１７００℃の範囲に加熱可能に構成される。また放熱部４６ｂの外径をｄ１（図２）とし、インゴット２５の直径をＤ（図４）とするとき、ｄ１／Ｄは０．０１〜１．０、好ましくは０．１〜０．６に設定される。更に伝導部４６ｃの外径をｄ２（図３）とするとき、ｄ２／Ｄは０．０１〜０．８、好ましくは０．１〜０．３に設定される。放熱部４６ｂ上面に対向するシリコン融液１２の温度を１４３０〜１９００℃の範囲に設定し、ｄ１／Ｄを０．０１〜１．０の範囲に設定したのは、インゴット２５下面の中心における固液界面２６の高さがシリコン融液１２表面に対して１〜３０ｍｍ、好ましくは３〜１８ｍｍの範囲で高くするためである。またｄ２／Ｄを０．０１〜０．８の範囲に設定したのは、０．０１未満では放熱部４６ｂ上面に対向するシリコン融液１２の温度が十分に上昇せず、０．８を越えると放熱部４６ｂ上面に対向するシリコン融液１２の温度が上昇し過ぎて固液界面の縦断面が略Ｍ字状になるからである。
【００１９】
石英管４７は、受熱部４６ａ及び補助ヒータ４４を所定の間隔をあけて被覆する受熱被覆部４７ａと、放熱部４６ｂ下面を被覆するロア放熱被覆部４７ｂと、放熱部４６ｂ上面を被覆するアッパ放熱被覆部４７ｃと、伝導部４６ｃを被覆する伝導被覆部４７ｄとからなる（図１）。アッパ放熱被覆部４７ｃは透明石英により形成される。受熱被覆部４７ａの幅は膨出部４１の幅より僅かに大きく形成され、受熱被覆部４７ａの上面には所定の間隔（膨出部の幅分）をあけて第１及び第２ロッド５１，５２の下端が取付けられる。第１ロッド５１は膨出部４１及び筒部３７の外周面に鉛直方向に摺動可能に取付けられ、第２ロッド５２は膨出部４１の内周面に鉛直方向に摺動可能に取付けられる。また第１及び第２ロッド５１，５２の上端はチャンバ１１外に設けられた石英管駆動手段（図示せず）に連結される。これにより石英管４７は熱遮蔽部材３６に対して上下動可能に設けられる。
【００２０】
このように構成されたシリコン融液対流制御装置の動作を説明する。
先ず、主ヒータ１８に主ヒータ用電源（図示せず）から所定の電力を供給すると、石英るつぼ１３に投入された高純度のシリコン多結晶体が加熱・融解してシリコン融液１２になる。この状態でシリコン融液１２からインゴット２５を所定の引上げ速度、即ちインゴット２５内が格子間シリコン型点欠陥の凝集体及び空孔型点欠陥の凝集体の存在しないパーフェクト領域となる引上げ速度で引上げる。同時に補助ヒータ４４に補助ヒータ用電源から所定の電力を供給すると、補助ヒータ４４が熱伝導体４６の受熱部を加熱し、この熱が伝導部４６ｃを通って放熱部４６ｂに伝わり放熱部４６ｂから固液界面２６の中心に向って放散される。これにより放熱部４６ｂ上面に対向するシリコン融液１２が１４３０〜１９００℃の範囲内の所定値、例えば１６００℃に加熱されるので、石英るつぼ１３中心のシリコン融液１２に上昇する対流が発生する。この結果、この対流により固液界面２６が上凸状になる、即ち固液界面２６の中心がシリコン融液１２表面の延長面より上方に位置するため、固液界面２６の中心近傍の鉛直方向の温度勾配が大きくなり、固液界面２６の中心近傍の鉛直方向の温度勾配と、固液界面２６の周縁近傍の鉛直方向の温度勾配との差が小さくなる。従って、略全長にわたって無欠陥で高品質のインゴット２５を比較的容易に製造できる。
【００２１】
図５〜図７は本発明の第２の実施の形態を示す。図５〜図７において図１〜図３と同一符号は同一部品を示す。
この実施の形態では、熱源６３が、チャンバ１１外に設けられレーザ光を発生するレーザ発生手段６４と、レーザ発生手段６４の発したレーザ光を受けて熱に変換しこの熱をシリコン融液１２中のインゴット２５下方に導き更にインゴット２５下面の中心に向って放散する熱伝導体６６と、熱伝導体６６の周面を被覆しかつ熱遮蔽部材３６に対して上下動可能に設けられた石英管６７と、熱伝導体６６及び石英管６７間に充填された熱源用断熱部材４８とを有する。
【００２２】
レーザ発生手段６４としては、ＣＯ２ガスを用いた気体レーザ発生手段や、ルビーやＹＡＧ等を用いた固体レーザ発生手段等が挙げられる。またレーザ発生手段６４が発したレーザ光は膨出部４１を貫通して熱伝導体６６の受光熱変換部６６ａ上面に照射されるように構成される。熱伝導体６６は、熱遮蔽部材３６下端及びシリコン融液１２表面間に位置しかつレーザ発生手段６４に対向して設けられた受光熱変換部６６ａと、シリコン融液１２中でインゴット２５下面の中心に対向して設けられた放熱部４６ｂと、受光熱変換部６６ａ及び放熱部４６ｂを連結し受光熱変換部６６ａでレーザ光から変換された熱を放熱部４６ｂに導く伝導部４６ｃとからなる。上記受光熱変換部６６ａ、放熱部４６ｂ及び伝導部４６ｃはソリッドカーボンにより一体的に形成される。
【００２３】
レーザ発生手段６４から発せられたレーザ光の強度は、受光熱変換部６６ａを１４５０〜２０００℃、好ましくは１６００〜１８５０℃の範囲に加熱可能な強度に設定され、これにより放熱部４６ｂはこの放熱部４６ｂ上面に対向するシリコン融液１２を１４３０〜１９００℃、好ましくは１５００〜１７００℃の範囲に加熱可能に構成される。また石英管６７は、受光熱変換部６６ａを所定の間隔をあけて被覆する受光被覆部６７ａと、放熱部４６ｂ下面を被覆するロア放熱被覆部４７ｂと、放熱部４６ｂ上面を被覆する透明石英製のアッパ放熱被覆部４７ｃと、伝導部４６ｃを被覆する伝導被覆部４７ｄとからなる。受光被覆部６７ａの幅は膨出部４１の幅より僅かに大きく形成され（図５）、受光被覆部６７ａの上面には所定の間隔（膨出部の幅分）をあけて第１及び第２ロッド５１，５２の下端が取付けられる。上記以外は第１の実施の形態と同一に構成される。
【００２４】
このように構成されたシリコン融液対流制御装置の動作を説明する。
シリコン融液１２からインゴット２５を所定の引上げ速度、即ちインゴット２５内が格子間シリコン型点欠陥の凝集体及び空孔型点欠陥の凝集体の存在しないパーフェクト領域となる引上げ速度で引上げるときに、レーザ発生手段６４が所定の強度のレーザ光を熱伝導体６６の受光熱変換部６６ａに照射することにより、この受光熱変換部６６ａが加熱されると、この熱が伝導部４６ｃを通って放熱部４６ｂに伝わり放熱部４６ｂから固液界面２６の中心に向って放散される。これにより放熱部４６ｂ上面に対向するシリコン融液１２が１４３０〜１９００℃の範囲内の所定値、例えば１６００℃に加熱されるので、石英るつぼ１３中心のシリコン融液１２に上昇する対流が発生する。この結果、第１の実施の形態と同様に、略全長にわたって無欠陥で高品質のインゴット２５を比較的容易に製造できる。
【００２５】
図８〜図１０は本発明の第３の実施の形態を示す。図８〜図１０において図１〜図３と同一符号は同一部品を示す。
この実施の形態では、熱源７３が、シリコン融液１２中でインゴット２５下面の中心に対向して設けられかつチャンバ１１外から配索された一対のカーボン電極４９，４９により電力が供給される補助ヒータ４４と、シリコン融液１２中の一対のカーボン電極４９，４９及び補助ヒータ４４を被覆しかつ熱遮蔽部材３６に対して上下動可能に設けられた石英管７７と、石英管７７中の一対のカーボン電極４９，４９間に設けられた石英製の絶縁部材７８とを有する。
【００２６】
一対のカーボン電極４９，４９はシリコン融液１２中を通りかつ膨出部４１を貫通して配索される。これらのカーボン電極４９，４９の一端は補助ヒータ４４に電気的に接続され、他端はチャンバ１１外に設けられた補助ヒータ用電源（図示せず）に電気的に接続される。補助ヒータ４４には、この補助ヒータ４４上面に対向するシリコン融液１２を１４３０〜１９００℃、好ましくは１５００〜１７００℃の範囲に加熱可能な電力が補助ヒータ用電源から供給されるようになっている。
【００２７】
石英管７７は、シリコン融液１２中の一対のカーボン電極４９，４９を被覆する電極被覆部７７ａと、補助ヒータ４４を被覆する透明石英製のヒータ被覆部７７ｂと、熱遮蔽部材３６下端及びシリコン融液１２表面間に位置しかつ膨出部４１の幅より僅かに大きく形成された取付部７７ｃとからなる。取付部７７ｃの上面には所定の間隔（膨出部の幅分）をあけて第１及び第２ロッド５１，５２の下端が取付けられる。なお、石英管７７の電極被覆部７７ａの直径は第１の実施の形態における石英管の伝導被覆部より細く形成される。また、絶縁部材７８は、一対のカーボン電極４９，４９の接触を阻止するために、一対のカーボン電極４９，４９間や、電極被覆部７７ａ及びカーボン電極４９間に設けられる。上記以外は第１の実施の形態と同一に構成される。
【００２８】
このように構成されたシリコン融液対流制御装置の動作を説明する。
シリコン融液１２からインゴット２５を所定の引上げ速度、即ちインゴット２５内が格子間シリコン型点欠陥の凝集体及び空孔型点欠陥の凝集体の存在しないパーフェクト領域となる引上げ速度で引上げるときに、補助ヒータ４４に補助ヒータ用電源から所定の電力を供給すると、補助ヒータ４４の発生した熱が固液界面２６の中心に向って放散される。これにより補助ヒータ４４上面に対向するシリコン融液１２が１４３０〜１９００℃の範囲内の所定値、例えば１６００℃に加熱されるので、石英るつぼ１３中心のシリコン融液１２に上昇する対流が発生する。この結果、第１の実施の形態と同様に、略全長にわたって無欠陥で高品質のインゴット２５を比較的容易に製造できる。
【００２９】
図１１〜図１３は本発明の第４の実施の形態を示す。図１１〜図１３において図１〜図３と同一符号は同一部品を示す。
この実施の形態では、熱源８３が、チャンバ１１外に設けられレーザ光を発生するレーザ発生手段６４と、レーザ発生手段６４の発したレーザ光を受けてシリコン融液１２中のインゴット２５下方に導き更にレーザ光をインゴット２５下面の中心に向って放散する光伝導体８６と、光伝導体８６の周面を被覆しかつ熱遮蔽部材３６に対して上下動可能に設けられた石英管８７とを有する。
【００３０】
レーザ発生手段６４が発したレーザ光は膨出部４１を貫通して光伝導体８６の受光部８６ａ上面に照射されるように構成される。光伝導体８６は、熱遮蔽部材３６下端及びシリコン融液１２表面間に位置しかつレーザ発生手段６４に対向して設けられた受光部８６ａと、シリコン融液１２中でインゴット２５下面の中心に対向して設けられた散光部８６ｂと、受光部８６ａ及び散光部８６ｂを連結し受光部８６ａで受けたレーザ光を散光部８６ｂに導く伝導部８６ｃとからなる。上記受光部８６ａ、散光部８６ｂ及び伝導部８６ｃは石英により一体的に形成される。
【００３１】
レーザ発生手段６４から発せられたレーザ光の強度は、散光部８６ｂから放散されたレーザ光が散光部８６ｂ上面に対向するシリコン融液１２を１４３０〜１９００℃、好ましくは１５００〜１７００℃の範囲に加熱可能な強度に設定される。また石英管８７は、受光部８６ａを所定の間隔をあけて被覆する受光被覆部８７ａと、散光部８６ｂ下面を被覆するロア散光被覆部８７ｂと、散光部８６ｂ上面を被覆する透明石英製のアッパ散光被覆部８７ｃと、伝導部８６ｃを被覆する伝導被覆部８７ｄとからなる。受光被覆部８７ａの幅は膨出部４１の幅より僅かに大きく形成され（図１１）、受光被覆部８７ａの上面には所定の間隔（膨出部の幅分）をあけて第１及び第２ロッド５１，５２の下端が取付けられる。なお、石英管８７の伝導被覆部８７ｄの直径は第１の実施の形態における石英管の伝導被覆部より細く形成される。また伝導部８６ｃと伝導被覆部８７ｄとの間には、ソリッドカーボン製の光遮蔽部材８８が充填される。上記以外は第１の実施の形態と同一に構成される。
【００３２】
このように構成されたシリコン融液対流制御装置の動作を説明する。
シリコン融液１２からインゴット２５を所定の引上げ速度、即ちインゴット２５内が格子間シリコン型点欠陥の凝集体及び空孔型点欠陥の凝集体の存在しないパーフェクト領域となる引上げ速度で引上げるときに、レーザ発生手段６４が所定の強度のレーザ光を光伝導体８６の受光部８６ａに照射すると、このレーザ光は受光部８６ａから伝導部８６ｃを通って散光部８６ｂに導かれた後に、固液界面２６の中心に向って放散される。このレーザ光の放散により放熱部８６ｂ上面に対向するシリコン融液１２が１４３０〜１９００℃の範囲内の所定値、例えば１６００℃に加熱されるので、石英るつぼ１３中心のシリコン融液１２に上昇する対流が発生する。この結果、第１の実施の形態と同様に、略全長にわたって無欠陥で高品質のインゴット２５を比較的容易に製造できる。
【００３３】
図１４は本発明の第５の実施の形態を示す。図１４において図１と同一符号は同一部品を示す。
この実施の形態では、第１及び第２ロッド５１，５２が膨出部４１を貫通しかつ一対のカーボン電極４９，４９をそれぞれ被覆する筒状に形成され、これにより石英管４７の受熱被覆部４７ａの幅が膨出部４１の幅より大幅に小さく形成される。上記以外は第１の実施の形態と同一に構成される。
このように構成されたシリコン融液対流制御装置では、石英管４７の受熱被覆部４７ａを小型化できるので、熱遮蔽部材３６下面とシリコン融液１２表面との間を通過する不活性ガスが第１の実施の形態よりスムーズに流れる。上記以外の動作は第１の実施の形態の動作と略同様であるので、繰返しの説明を省略する。
【００３４】
図１５は本発明の第６の実施の形態を示す。図１５において図５と同一符号は同一部品を示す。
この実施の形態では、第１及び第２ロッド５１，５２が膨出部４１を貫通して配設され、これにより石英管６７の受光被覆部６７ａの幅が膨出部４１の幅より大幅に小さく形成される。上記以外は第２の実施の形態と同一に構成される。
このように構成されたシリコン融液対流制御装置では、石英管６７の受光被覆部６７ａを小型化できるので、熱遮蔽部材３９下面とシリコン融液１２表面との間を通過する不活性ガスが第２の実施の形態よりスムーズに流れる。上記以外の動作は第２の実施の形態の動作と略同様であるので、繰返しの説明を省略する。
【００３５】
図１６は本発明の第７の実施の形態を示す。図１６において図８と同一符号は同一部品を示す。
この実施の形態では、第１及び第２ロッド５１，５２が膨出部４１を貫通しかつ一対のカーボン電極４９，４９をそれぞれ被覆する筒状に形成され、これにより石英管７７の取付部７７ｃの幅が膨出部４１の幅より大幅に小さく形成される。上記以外は第３の実施の形態と同一に構成される。
このように構成されたシリコン融液対流制御装置では、石英管７７の取付部７７ｃを小型化できるので、熱遮蔽部材３９下面とシリコン融液１２表面との間を通過する不活性ガスが第３の実施の形態よりスムーズに流れる。上記以外の動作は第３の実施の形態の動作と略同様であるので、繰返しの説明を省略する。
【００３６】
図１７は本発明の第８の実施の形態を示す。図１７において図１１と同一符号は同一部品を示す。
この実施の形態では、第１及び第２ロッド５１，５２が膨出部４１を貫通して配設され、これにより石英管８７の受光被覆部８７ａの幅が膨出部４１の幅より大幅に小さく形成される。上記以外は第４の実施の形態と同一に構成される。
このように構成されたシリコン融液対流制御装置では、石英管８７の受光被覆部８７ａを小型化できるので、熱遮蔽部材３９下面とシリコン融液１２表面との間を通過する不活性ガスが第４の実施の形態よりスムーズに流れる。上記以外の動作は第４の実施の形態の動作と略同様であるので、繰返しの説明を省略する。
【００３７】
【発明の効果】
以上述べたように、本発明によれば、シリコン融液から引上げられるインゴットとシリコン融液との固液界面より下方のシリコン融液中でインゴット下面の中心に向って放熱する熱源を設けたので、この熱源から固液界面の中心に向って放熱しながら、シリコン融液からインゴットを引上げると、石英るつぼ中心のシリコン融液に上昇する対流が発生し、この対流により固液界面形状が上凸状になる。この結果、固液界面の中心がシリコン融液表面の延長面より上方に位置するため、固液界面の中心近傍の鉛直方向の温度勾配が大きくなり、固液界面の中心近傍の鉛直方向の温度勾配と、固液界面の周縁近傍の鉛直方向の温度勾配との差が小さくなる。従って、略全長にわたって無欠陥で高品質のシリコン単結晶のインゴットを比較的容易に製造できる。
【図面の簡単な説明】
【図１】本発明第１実施形態のシリコン融液対流制御装置を含む図４のＡ部拡大断面図。
【図２】図１のＢ−Ｂ線断面図。
【図３】図１のＣ−Ｃ線断面図。
【図４】その制御装置を含むシリコン単結晶引上げ装置の縦断面図。
【図５】本発明の第２実施形態を示す図１に対応する断面図。
【図６】図５のＤ−Ｄ線断面図。
【図７】図５のＥ−Ｅ線断面図。
【図８】本発明の第３実施形態を示す図１に対応する断面図。
【図９】図８のＦ−Ｆ線断面図。
【図１０】図８のＧ−Ｇ線断面図。
【図１１】本発明の第４実施形態を示す図１に対応する断面図。
【図１２】図１１のＨ−Ｈ線断面図。
【図１３】図１１のＩ−Ｉ線断面図。
【図１４】本発明の第５実施形態を示す図１に対応する断面図。
【図１５】本発明の第６実施形態を示す図５に対応する断面図。
【図１６】本発明の第７実施形態を示す図８に対応する断面図。
【図１７】本発明の第８実施形態を示す図１１に対応する断面図。
【符号の説明】
１１　チャンバ
１２　シリコン融液
１３　石英るつぼ
１８　主ヒータ
２５　インゴット
２６　固液界面
３６　熱遮蔽部材
４３，６３，７３，８３　熱源
４４　補助ヒータ
４６，６６　熱伝導体
４７，６７，７７，８７　石英管
４８　熱源用断熱部材
４９　カーボン電極
６４　レーザ発生手段
７８　絶縁部材
８６　光伝導体
８８　光遮蔽部材[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a device for controlling the convection of a silicon melt when pulling an ingot of a silicon single crystal from a silicon melt stored in a quartz crucible, and a control method therefor.
[0002]
[Prior art]
Conventionally, as a method of manufacturing a silicon single crystal, a method of pulling an ingot of a silicon single crystal by a Czochralski method (hereinafter, referred to as a CZ method) is known. In this CZ method, a seed crystal is brought into contact with a silicon melt stored in a quartz crucible, and the seed crystal is pulled up while rotating the quartz crucible and the seed crystal, thereby producing a cylindrical silicon single crystal ingot. It is.
On the other hand, in a process of manufacturing a semiconductor integrated circuit, as a cause of lowering the yield, a micro defect of an oxygen precipitate serving as a nucleus of an oxidation-induced stacking fault (hereinafter, referred to as OSF) or a crystal is a cause. The presence of particles (Crystal Originated Particles, hereinafter referred to as COP) or interstitial-type large dislocations (hereinafter, referred to as L / D) is cited. OSF introduces microscopic defects serving as nuclei during crystal growth, becomes apparent in a thermal oxidation step or the like when manufacturing a semiconductor device, and causes defects such as an increase in leak current of the manufactured device. COPs are pits caused by crystals that appear on the wafer surface when the mirror-polished silicon wafer is washed with a mixed solution of ammonia and hydrogen peroxide. When this wafer is measured by a particle counter, the pits are also detected as light scattering defects together with the original particles.
[0003]
This COP causes deterioration of electrical characteristics such as a time-dependent dielectric breakdown characteristic (Time Dependent Breakdown, TDDB) of the oxide film and a dielectric breakdown voltage characteristic (Time Zero Dielectric Breakdown, TZDB) of the oxide film. Also, if COP exists on the wafer surface, a step is generated in a device wiring process, which may cause disconnection. This also causes a leak or the like in the element isolation portion, and lowers the product yield. Further, L / D is also called a dislocation cluster because a pit is generated when a silicon wafer having this defect is immersed in a selective etching solution containing hydrofluoric acid as a main component. This L / D also causes deterioration of electrical characteristics such as leak characteristics and isolation characteristics. As a result, it is necessary to reduce OSF, COP and L / D from a silicon wafer used for manufacturing a semiconductor integrated circuit.
[0004]
A method for manufacturing a silicon single crystal ingot for cutting a defect-free silicon wafer having no OSF, COP and L / D is disclosed in Japanese Patent Application Laid-Open No. 11-1393 corresponding to US Pat. No. 6,045,610. Have been. In general, when a silicon single crystal ingot is pulled up at a high speed, a region [V] in which agglomerates of vacancy type point defects are predominantly formed inside the ingot, and when the ingot is pulled up at a low speed, the ingot is pulled up. A region [I] in which an aggregate of interstitial silicon type point defects predominantly exists is formed. For this reason, in the above-mentioned manufacturing method, by pulling the ingot at an optimum pulling speed, it is possible to manufacture a silicon single crystal ingot consisting of a perfect region [P] in which the above-mentioned point defect aggregates do not exist.
[0005]
On the other hand, there has been disclosed a method of producing a defect-free crystal in consideration of the shape of a solid-liquid interface between an ingot and a silicon melt when pulling an ingot of a silicon single crystal from the silicon melt by the CZ method (for example, see, for example, Japanese Patent Application Laid-Open Publication No. H11-157556). And Patent Document 1). In the method for producing this defect-free crystal, the adjustment of the shape of the solid-liquid interface is performed by adjusting the height of the solid-liquid interface at the center of the lower surface of the ingot, and the adjustment of the temperature distribution of the periphery of the lower surface of the ingot is performed. This is performed by adjusting the temperature gradient in the pulling direction of the outer periphery of the ingot. Adjustment of the height of the solid-liquid interface at the center of the lower surface of the ingot is applied to the silicon melt so that the height of the solid-liquid interface at the center of the lower surface of the ingot is higher than the surface of the silicon melt by 10 mm or more. Adjustment of one or more selected from the group consisting of adjusting the strength of the magnetic field, adjusting the rotation speed per unit time of the quartz crucible storing the silicon melt, and adjusting the rotation speed per unit time of the ingot. Done by The magnetic field is generated by applying a predetermined current to a solenoid provided at a predetermined interval from the outer peripheral surface of the quartz crucible, and is applied to the silicon melt.
[0006]
In the method of manufacturing a defect-free crystal configured as described above, when pulling an ingot of a silicon single crystal from a silicon melt, the relationship between the shape of the solid-liquid interface and the temperature distribution of the lower edge of the ingot during the pulling is determined. By properly adjusting, a defect-free silicon single crystal ingot can be manufactured stably and with good reproducibility. That is, in both the pulling direction of the ingot and the plane direction of the radius, an ingot having a defect-free region over a wide range can be manufactured stably and with good reproducibility. As a result, the number of defect-free wafers obtained by slicing the ingot increases, so that the yield can be improved, and the large-diameter wafer obtained by slicing the large-diameter ingot after pulling up the large-diameter ingot is large. The entire surface is defect-free.
[0007]
[Patent Document 1]
JP-A-11-1393 corresponding to U.S. Pat. No. 6,045,610.
[0008]
[Problems to be solved by the invention]
However, in the conventional method of manufacturing a silicon single crystal ingot disclosed in Patent Document 1, the vertical temperature gradient near the solid-liquid interface between the silicon single crystal ingot and the silicon melt is controlled to be uniform. Since this control is affected by changes in the remaining amount of silicon melt and changes in convection, it has been difficult to manufacture defect-free silicon single crystals over the entire length of the straight body of the ingot.
Further, in the method of manufacturing a defect-free crystal disclosed in Patent Document 1 described above, as the diameter of a silicon single crystal ingot increases, the size of a solenoid that generates a magnetic field needs to be increased. Since the rate of enlargement is significantly higher than the rate of increase in diameter of the ingot, there is a possibility that the production of the solenoid may become difficult in terms of both technology and funding as the diameter of the ingot increases.
An object of the present invention is to provide a silicon melt convection control device and a control method therefor, which can relatively easily produce a defect-free silicon single crystal ingot even if the silicon single crystal ingot has a large diameter. .
[0009]
[Means for Solving the Problems]
As shown in FIGS. 1 and 4, the invention according to claim 1 includes a quartz crucible 13 provided in a chamber 11 and storing a silicon melt 12, and a silicon melt 12 surrounding an outer peripheral surface of the quartz crucible 13. And a main heater 18 for heating the silicon single crystal.
The characteristic configuration thereof is provided with a heat source 43 that radiates heat toward the center of the lower surface of the ingot 25 in the silicon melt 12 below the solid-liquid interface 26 between the ingot 25 pulled up from the silicon melt 12 and the silicon melt 12. The solid-liquid interface 26 is configured so as to be upwardly convex due to heat radiation from the heat source 43.
[0010]
As shown in FIGS. 1 and 4, the invention according to claim 7 stores a silicon melt 12 capable of pulling up an ingot 25 in a quartz crucible 13 provided in a chamber 11, wherein the interstitial silicon is filled in the ingot 25. It is an improvement in a silicon single crystal pulling method for pulling up the ingot 25 at a pulling speed that is a perfect region where there are no aggregates of mold point defects and aggregates of vacancy type point defects.
The characteristic configuration is that the heat source 43 radiates heat toward the center of the lower surface of the ingot 25 in the silicon melt 12 below the solid-liquid interface 26 between the ingot 25 and the silicon melt 12, and the solid-liquid interface 26 has an upward convex shape. The heat source 43 is controlled so that
[0011]
In the silicon melt convection control device according to the first aspect or the silicon melt convection control method according to the seventh aspect, the silicon melt 12 is radiated from the heat source 43 toward the center of the solid-liquid interface 26. When the ingot 25 is pulled up from the above, a convection that rises in the silicon melt 12 at the center of the quartz crucible 13 is generated, and the convection causes the solid-liquid interface 26 to be upwardly convex. As a result, since the center of the solid-liquid interface 26 is located above the extension of the surface of the silicon melt 12, the temperature gradient in the vertical direction near the center of the solid-liquid interface 26 becomes large, and the center near the center of the solid-liquid interface 26 is increased. The difference between the vertical temperature gradient and the vertical temperature gradient near the periphery of the solid-liquid interface 26 is reduced.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, a first embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 4, a quartz crucible 13 for storing a silicon melt 12 is provided in a chamber 11 of the silicon single crystal pulling apparatus 10, and the outer peripheral surface of the quartz crucible 13 is covered with a graphite susceptor 14. The lower surface of the quartz crucible 13 is fixed to the upper end of a support shaft 16 via the graphite susceptor 14, and the lower portion of the support shaft 16 is connected to a crucible driving unit 17. The crucible driving means 17 includes a first rotation motor (not shown) for rotating the quartz crucible 13 and a lifting / lowering motor for moving the quartz crucible 13 up and down, and these motors can rotate the quartz crucible 13 in a predetermined direction. At the same time, it can be moved up and down. The outer peripheral surface of the quartz crucible 13 is surrounded by a main heater 18 at a predetermined interval from the quartz crucible 13, and the main heater 18 is surrounded by a heat retaining tube 19. The main heater 18 is electrically connected to a main heater power supply (not shown).
[0013]
A cylindrical casing 21 is connected to the upper end of the chamber 11. The casing 21 is provided with a pulling means 22. The pulling means 22 includes a pulling head (not shown) rotatably provided at the upper end of the casing 21 in a horizontal state, a second rotation motor (not shown) for rotating the head, and a quartz crucible 13 from the head. And a pull-up motor (not shown) provided in the head for winding up or feeding out the wire cable 23. At the lower end of the wire cable 23 is attached a seed crystal 24 for dipping in the silicon melt 12 and pulling up the silicon single crystal ingot 25.
[0014]
Further, the chamber 11 is connected to gas supply / discharge means 28 for supplying an inert gas to the outer peripheral surface of the ingot being pulled up and discharging the inert gas from the inner peripheral surface of the crucible of the chamber 11. The gas supply / discharge means 28 has one end connected to the peripheral wall of the casing 21 and the other end connected to a supply pipe 29 connected to a tank (not shown) for storing the inert gas, and one end connected to the lower wall of the chamber 11. The other end has a discharge pipe 30 connected to a vacuum pump (not shown). The supply pipe 29 and the discharge pipe 30 are respectively provided with first and second flow control valves 31 and 32 for controlling the flow rate of the inert gas flowing through these pipes 29 and 30.
[0015]
On the other hand, a heat shielding member 36 surrounding the outer peripheral surface of the ingot 25 is provided between the outer peripheral surface of the ingot 25 and the inner peripheral surface of the quartz crucible 13. The heat shielding member 36 is formed in a cylindrical shape and shields radiant heat from the main heater 18, a flange portion 38 which is connected to the upper edge of the cylindrical portion 37 and projects outward in a substantially horizontal direction, A bulging portion 41 is provided at a lower portion of the portion 37 so as to bulge inward of the cylindrical portion 37. The heat shielding member 36 is fixed in the chamber 11 by placing the flange portion 38 on the heat retaining cylinder 19 such that the lower edge of the cylindrical portion 37 is located a predetermined distance above the surface of the silicon melt 12. Is done. The cylindrical portion 37 and the bulging portion 41 are formed of graphite, graphite whose surface is coated with SiC, or the like. The inside of the bulging portion 41 is filled with a bulging portion heat insulating member 42, and the bulging portion heat insulating member 42 is formed of carbon felt, that is, a nonwoven fabric of carbon fiber.
[0016]
On the other hand, as shown in FIGS. 1 to 4, a heat source 43 that radiates heat toward the center of the lower surface of the ingot 25 is provided in the silicon melt 12 below the solid-liquid interface 26 between the ingot 25 and the silicon melt 12. Can be The heat source 43 receives the heat generated by the auxiliary heater 44 provided between the lower end of the heat shielding member 36 and the surface of the silicon melt 12 and guides the heat below the ingot 25 in the silicon melt 12. A heat conductor 46 radiating toward the center of the lower surface of the ingot 25, a quartz tube 47 covering the peripheral surfaces of the auxiliary heater 44 and the heat conductor 46, and a heat source filled between the heat conductor 46 and the quartz tube 47. A heat insulating member 48 (FIG. 3).
[0017]
The auxiliary heater 44 is constituted by a small carbon heater. One end of a pair of carbon electrodes 49, 49, which is routed from outside the chamber 11 and penetrates the bulging portion 41, is electrically connected to the auxiliary heater 44, and the other end of the pair of carbon electrodes 49, 49 is connected to the chamber. 11 is electrically connected to an auxiliary heater power supply (not shown) provided outside. The heat conductor 46 includes a heat receiving portion 46a provided facing the auxiliary heater 44, a heat radiating portion 46b provided facing the center of the lower surface of the ingot 25 in the silicon melt 12, a heat receiving portion 46a and a heat radiating portion. And a conducting part 46c for connecting the heat receiving part 46a to the heat radiating part 46b. The heat receiving portion 46a, the heat radiating portion 46b, and the conductive portion 46c are integrally formed of solid carbon.
[0018]
The auxiliary heater 44 is configured such that electric power capable of heating the heat receiving portion 46a to 1450 to 2000 ° C., preferably 1600 to 1850 ° C. is supplied from a power supply for the auxiliary heater, whereby the heat radiating portion 46b is The silicon melt 12 facing the upper surface is configured to be heatable in a range of 1430 to 1900 ° C., preferably 1500 to 1700 ° C. Also, the outer diameter of the heat radiating portion 46b is d 1 (FIG. 2), and when the diameter of the ingot 25 is D (FIG. 4), d 1 / D is set to 0.01 to 1.0, preferably 0.1 to 0.6. Further, the outer diameter of the conductive portion 46c is set to d. 2 (FIG. 3), d 2 / D is set to 0.01 to 0.8, preferably 0.1 to 0.3. The temperature of the silicon melt 12 facing the upper surface of the heat radiating portion 46b is set in a range of 1430 to 1900 ° C., and d 1 The reason why / D is set in the range of 0.01 to 1.0 is that the height of the solid-liquid interface 26 at the center of the lower surface of the ingot 25 is 1 to 30 mm, preferably 3 to 18 mm with respect to the surface of the silicon melt 12. This is to increase the range. Also d 2 The reason why / D is set in the range of 0.01 to 0.8 is that the temperature of the silicon melt 12 facing the upper surface of the heat radiating portion 46b does not rise sufficiently when the value is less than 0.01, and the temperature becomes higher when the value exceeds 0.8. This is because the temperature of the silicon melt 12 facing the upper surface of the portion 46b rises too much and the vertical section of the solid-liquid interface becomes substantially M-shaped.
[0019]
The quartz tube 47 includes a heat-receiving covering portion 47a that covers the heat-receiving portion 46a and the auxiliary heater 44 at predetermined intervals, a lower heat-radiating covering portion 47b that covers the lower surface of the heat-radiating portion 46b, and an upper heat-radiating portion that covers the upper surface of the heat radiating portion 46b. It comprises a covering portion 47c and a conducting covering portion 47d covering the conducting portion 46c (FIG. 1). The upper heat radiation covering portion 47c is formed of transparent quartz. The width of the heat receiving covering portion 47a is formed slightly larger than the width of the bulging portion 41, and the upper surface of the heat receiving covering portion 47a is spaced apart from the first and second rods 51 by a predetermined distance (the width of the bulging portion). The lower end of 52 is attached. The first rod 51 is vertically slidably mounted on the outer peripheral surfaces of the bulging portion 41 and the cylindrical portion 37, and the second rod 52 is vertically slidably mounted on the inner peripheral surface of the bulging portion 41. . The upper ends of the first and second rods 51 and 52 are connected to quartz tube driving means (not shown) provided outside the chamber 11. Thus, the quartz tube 47 is provided so as to be vertically movable with respect to the heat shielding member 36.
[0020]
The operation of the thus-configured silicon melt convection control device will be described.
First, when a predetermined electric power is supplied from a main heater power supply (not shown) to the main heater 18, the high-purity silicon polycrystal put in the quartz crucible 13 is heated and melted to form the silicon melt 12. In this state, the ingot 25 is pulled from the silicon melt 12 at a predetermined pulling speed, that is, a pulling speed at which the inside of the ingot 25 becomes a perfect region where there are no aggregates of interstitial silicon type point defects and no aggregates of vacancy type point defects. increase. At the same time, when a predetermined power is supplied from the power supply for the auxiliary heater to the auxiliary heater 44, the auxiliary heater 44 heats the heat receiving portion of the heat conductor 46, and this heat is transmitted to the heat radiating portion 46b through the conductive portion 46c and from the heat radiating portion 46b. Dissipated toward the center of the solid-liquid interface 26. As a result, the silicon melt 12 facing the upper surface of the heat radiating portion 46b is heated to a predetermined value within the range of 1430 to 1900 ° C., for example, 1600 ° C., so that a convection that rises in the silicon melt 12 at the center of the quartz crucible 13 is generated. . As a result, the convection causes the solid-liquid interface 26 to be upwardly convex, that is, since the center of the solid-liquid interface 26 is located above the extension of the surface of the silicon melt 12, the vertical direction near the center of the solid-liquid interface 26. Is large, and the difference between the vertical temperature gradient near the center of the solid-liquid interface 26 and the vertical temperature gradient near the periphery of the solid-liquid interface 26 is small. Therefore, a defect-free and high-quality ingot 25 can be manufactured relatively easily over substantially the entire length.
[0021]
5 to 7 show a second embodiment of the present invention. 5 to 7, the same reference numerals as those in FIGS. 1 to 3 indicate the same parts.
In this embodiment, a heat source 63 is provided outside the chamber 11 and generates laser light. The laser source 64 receives the laser light emitted from the laser generation means 64 and converts the heat into heat. A heat conductor 66 which is guided to a lower part of the ingot 25 and further diffuses toward the center of the lower surface of the ingot 25, and quartz which covers the peripheral surface of the heat conductor 66 and is provided so as to be vertically movable with respect to the heat shield member 36. It has a tube 67 and a heat source heat insulating member 48 filled between the heat conductor 66 and the quartz tube 67.
[0022]
As the laser generating means 64, CO 2 2 Gas laser generating means using gas, solid laser generating means using ruby, YAG, or the like can be used. Further, the laser light emitted from the laser generating means 64 is configured to penetrate the bulging portion 41 and irradiate the upper surface of the light receiving heat converting portion 66a of the heat conductor 66. The heat conductor 66 is located between the lower end of the heat shielding member 36 and the surface of the silicon melt 12 and is provided with a light-receiving heat converter 66 a provided opposite to the laser generating means 64. A heat radiating portion 46b provided to face the center and a conducting portion 46c connecting the light receiving heat converting portion 66a and the heat radiating portion 46b and guiding the heat converted from the laser beam by the light receiving heat converting portion 66a to the heat radiating portion 46b. . The light receiving heat converting section 66a, the heat radiating section 46b, and the conductive section 46c are integrally formed of solid carbon.
[0023]
The intensity of the laser beam emitted from the laser generating means 64 is set to an intensity capable of heating the light-receiving heat conversion section 66a to 1450 to 2000 ° C., preferably 1600 to 1850 ° C., so that the heat radiating section 46 b The silicon melt 12 facing the upper surface of the portion 46b is configured to be heatable at 1430 to 1900 ° C, preferably 1500 to 1700 ° C. Further, the quartz tube 67 is made of a light-receiving covering portion 67a that covers the light-receiving heat converting portion 66a at a predetermined interval, a lower heat-radiating covering portion 47b that covers the lower surface of the heat-radiating portion 46b, and a transparent quartz that covers the upper surface of the heat-radiating portion 46b. And a conductive covering portion 47d covering the conducting portion 46c. The width of the light receiving covering portion 67a is formed slightly larger than the width of the bulging portion 41 (FIG. 5), and the first and second light receiving covering portions 67a are spaced apart from each other by a predetermined distance (the width of the bulging portion). The lower ends of the two rods 51 and 52 are attached. Except for the above, the configuration is the same as that of the first embodiment.
[0024]
The operation of the thus-configured silicon melt convection control device will be described.
When the ingot 25 is pulled up from the silicon melt 12 at a predetermined pulling speed, that is, at a pulling speed at which the inside of the ingot 25 becomes a perfect region free of the aggregates of interstitial silicon type point defects and the aggregates of vacancy type point defects. When the laser generating means 64 irradiates the light-receiving heat converting portion 66a of the heat conductor 66 with laser light having a predetermined intensity, the light-receiving heat converting portion 66a is heated, and the heat passes through the conductive portion 46c. The heat is transmitted to the heat radiating portion 46b and is radiated from the heat radiating portion 46b toward the center of the solid-liquid interface 26. As a result, the silicon melt 12 facing the upper surface of the heat radiating portion 46b is heated to a predetermined value within the range of 1430 to 1900 ° C., for example, 1600 ° C., so that a convection is generated in the silicon melt 12 at the center of the quartz crucible 13. . As a result, similarly to the first embodiment, a defect-free and high-quality ingot 25 can be produced relatively easily over substantially the entire length.
[0025]
8 to 10 show a third embodiment of the present invention. 8 to 10, the same reference numerals as those in FIGS. 1 to 3 indicate the same parts.
In this embodiment, a heat source 73 is provided in the silicon melt 12 so as to face the center of the lower surface of the ingot 25, and is supplied with power by a pair of carbon electrodes 49, 49 which are routed from outside the chamber 11. A heater 44, a pair of carbon electrodes 49, 49 in the silicon melt 12, a quartz tube 77 that covers the auxiliary heater 44, and is provided to be vertically movable with respect to the heat shielding member 36; And a quartz insulating member 78 provided between the carbon electrodes 49, 49.
[0026]
A pair of carbon electrodes 49, 49 are routed through the silicon melt 12 and through the bulge 41. One ends of these carbon electrodes 49, 49 are electrically connected to the auxiliary heater 44, and the other ends are electrically connected to an auxiliary heater power supply (not shown) provided outside the chamber 11. An electric power capable of heating the silicon melt 12 facing the upper surface of the auxiliary heater 44 to 1430 to 1900 ° C., preferably 1500 to 1700 ° C. is supplied to the auxiliary heater 44 from an auxiliary heater power supply. I have.
[0027]
The quartz tube 77 includes an electrode covering portion 77a that covers the pair of carbon electrodes 49, 49 in the silicon melt 12, a heater covering portion 77b made of transparent quartz that covers the auxiliary heater 44, a lower end of the heat shielding member 36, and silicon. And a mounting portion 77c located between the surfaces of the melt 12 and slightly larger than the width of the bulging portion 41. The lower ends of the first and second rods 51, 52 are mounted on the upper surface of the mounting portion 77c at a predetermined interval (the width of the bulging portion). The diameter of the electrode coating portion 77a of the quartz tube 77 is smaller than the diameter of the conductive coating portion of the quartz tube in the first embodiment. The insulating member 78 is provided between the pair of carbon electrodes 49, 49 and between the electrode covering portion 77 a and the carbon electrode 49 in order to prevent contact between the pair of carbon electrodes 49, 49. Except for the above, the configuration is the same as that of the first embodiment.
[0028]
The operation of the thus-configured silicon melt convection control device will be described.
When the ingot 25 is pulled up from the silicon melt 12 at a predetermined pulling speed, that is, at a pulling speed at which the inside of the ingot 25 becomes a perfect region where the aggregates of interstitial silicon type point defects and the aggregates of vacancy type point defects do not exist. When a predetermined power is supplied from the auxiliary heater power supply to the auxiliary heater 44, the heat generated by the auxiliary heater 44 is dissipated toward the center of the solid-liquid interface 26. As a result, the silicon melt 12 facing the upper surface of the auxiliary heater 44 is heated to a predetermined value in the range of 1430 to 1900 ° C., for example, 1600 ° C., so that a convection that rises in the silicon melt 12 at the center of the quartz crucible 13 is generated. . As a result, similarly to the first embodiment, a defect-free and high-quality ingot 25 can be produced relatively easily over substantially the entire length.
[0029]
11 to 13 show a fourth embodiment of the present invention. 11 to 13, the same reference numerals as those in FIGS. 1 to 3 indicate the same parts.
In this embodiment, a heat source 83 is provided outside the chamber 11 to generate a laser beam, and the heat source 83 receives the laser beam emitted from the laser generating unit 64 and guides the laser beam below the ingot 25 in the silicon melt 12. Further, a photoconductor 86 that radiates the laser light toward the center of the lower surface of the ingot 25 and a quartz tube 87 that covers the peripheral surface of the photoconductor 86 and that is provided to be vertically movable with respect to the heat shielding member 36 are provided. Have.
[0030]
The laser light emitted from the laser generating means 64 is configured to penetrate the bulging portion 41 and irradiate the upper surface of the light receiving portion 86a of the photoconductor 86. The photoconductor 86 is located between the lower end of the heat shielding member 36 and the surface of the silicon melt 12 and is provided opposite to the laser generating means 64. The light-transmitting portion 86b includes a light-transmitting portion 86b and a conductive portion 86c that connects the light-receiving portion 86a and the light-scattering portion 86b and guides the laser light received by the light-receiving portion 86a to the light-scattering portion 86b. The light receiving section 86a, the light scattering section 86b, and the conduction section 86c are integrally formed of quartz.
[0031]
The intensity of the laser light emitted from the laser generating means 64 is such that the laser light emitted from the light scattering part 86b causes the silicon melt 12 facing the upper surface of the light scattering part 86b to be in the range of 1430 to 1900 ° C., preferably 1500 to 1700 ° C. The heating intensity is set. The quartz tube 87 includes a light-receiving covering portion 87a that covers the light-receiving portion 86a at predetermined intervals, a lower light-scattering covering portion 87b that covers the lower surface of the light-scattering portion 86b, and an upper made of transparent quartz that covers the upper surface of the light-scattering portion 86b. It is composed of a diffused coating 87c and a conductive coating 87d that covers the conductive part 86c. The width of the light-receiving covering portion 87a is formed slightly larger than the width of the bulging portion 41 (FIG. 11), and the first and second light-receiving covering portions 87a are spaced apart from each other by a predetermined distance (the width of the bulging portion). The lower ends of the two rods 51 and 52 are attached. The diameter of the conductive coating portion 87d of the quartz tube 87 is smaller than the diameter of the conductive coating portion of the quartz tube in the first embodiment. A light shielding member 88 made of solid carbon is filled between the conductive portion 86c and the conductive coating portion 87d. Except for the above, the configuration is the same as that of the first embodiment.
[0032]
The operation of the thus-configured silicon melt convection control device will be described.
When the ingot 25 is pulled up from the silicon melt 12 at a predetermined pulling speed, that is, at a pulling speed at which the inside of the ingot 25 becomes a perfect region where the aggregates of interstitial silicon type point defects and the aggregates of vacancy type point defects do not exist. When the laser generating means 64 irradiates the light receiving portion 86a of the photoconductor 86 with laser light of a predetermined intensity, the laser light is guided from the light receiving portion 86a to the light diffusing portion 86b through the conducting portion 86c, and then solid-liquid. Dissipated toward the center of interface 26. Since the silicon melt 12 facing the upper surface of the heat radiating portion 86b is heated to a predetermined value in the range of 1430 to 1900 ° C., for example, 1600 ° C. by the dissipation of the laser light, the silicon melt 12 rises to the silicon melt 12 at the center of the quartz crucible 13 Convection occurs. As a result, similarly to the first embodiment, a defect-free and high-quality ingot 25 can be manufactured relatively easily over substantially the entire length.
[0033]
FIG. 14 shows a fifth embodiment of the present invention. 14, the same reference numerals as those in FIG. 1 indicate the same parts.
In this embodiment, the first and second rods 51 and 52 are formed in a cylindrical shape that penetrates the bulging portion 41 and covers the pair of carbon electrodes 49 and 49, respectively. The width of 47 a is formed to be significantly smaller than the width of the bulging portion 41. Except for the above, the configuration is the same as that of the first embodiment.
In the silicon melt convection control device thus configured, since the heat receiving coating portion 47a of the quartz tube 47 can be miniaturized, the inert gas passing between the lower surface of the heat shielding member 36 and the surface of the silicon melt 12 is removed. It flows more smoothly than in the first embodiment. The operation other than the above is substantially the same as the operation of the first embodiment, and therefore, the description thereof will not be repeated.
[0034]
FIG. 15 shows a sixth embodiment of the present invention. 15, the same reference numerals as those in FIG. 5 indicate the same parts.
In this embodiment, the first and second rods 51 and 52 are disposed so as to penetrate the bulging portion 41, whereby the width of the light-receiving covering portion 67 a of the quartz tube 67 is significantly larger than the width of the bulging portion 41. It is formed small. Except for the above, the configuration is the same as that of the second embodiment.
In the silicon melt convection control device configured as described above, since the light-receiving covering portion 67a of the quartz tube 67 can be miniaturized, the inert gas passing between the lower surface of the heat shielding member 39 and the surface of the silicon melt 12 is discharged. It flows more smoothly than the second embodiment. The operation other than the above is substantially the same as the operation of the second embodiment, and thus the repeated explanation is omitted.
[0035]
FIG. 16 shows a seventh embodiment of the present invention. 16, the same reference numerals as those in FIG. 8 indicate the same parts.
In this embodiment, the first and second rods 51, 52 are formed in a cylindrical shape penetrating the bulging portion 41 and covering the pair of carbon electrodes 49, 49, respectively, whereby the mounting portion 77c of the quartz tube 77 is formed. Is significantly smaller than the width of the bulging portion 41. Except for the above, the configuration is the same as that of the third embodiment.
In the silicon melt convection control device configured as described above, since the mounting portion 77c of the quartz tube 77 can be downsized, the inert gas passing between the lower surface of the heat shielding member 39 and the surface of the silicon melt 12 becomes the third. It flows more smoothly than the embodiment. The operation other than the above is substantially the same as the operation of the third embodiment, and therefore, the description thereof will not be repeated.
[0036]
FIG. 17 shows an eighth embodiment of the present invention. 17, the same reference numerals as those in FIG. 11 indicate the same parts.
In this embodiment, the first and second rods 51 and 52 are disposed so as to penetrate the bulging portion 41, whereby the width of the light-receiving covering portion 87 a of the quartz tube 87 is significantly larger than the width of the bulging portion 41. It is formed small. Except for the above, the configuration is the same as that of the fourth embodiment.
In the silicon melt convection control device configured as described above, since the light-receiving covering portion 87a of the quartz tube 87 can be miniaturized, the inert gas passing between the lower surface of the heat shield member 39 and the surface of the silicon melt 12 is discharged. It flows more smoothly than in the fourth embodiment. The operation other than the above is substantially the same as the operation of the fourth embodiment, and therefore, the description thereof will not be repeated.
[0037]
【The invention's effect】
As described above, according to the present invention, the heat source that dissipates heat toward the center of the lower surface of the ingot in the silicon melt below the solid-liquid interface between the ingot pulled up from the silicon melt and the silicon melt is provided. When the ingot is pulled up from the silicon melt while radiating heat from this heat source toward the center of the solid-liquid interface, convection is generated in the silicon melt at the center of the quartz crucible, and the convection raises the shape of the solid-liquid interface. Become convex. As a result, since the center of the solid-liquid interface is located above the extended surface of the silicon melt surface, the temperature gradient in the vertical direction near the center of the solid-liquid interface increases, and the temperature in the vertical direction near the center of the solid-liquid interface increases. The difference between the gradient and the vertical temperature gradient near the periphery of the solid-liquid interface is reduced. Therefore, a defect-free high-quality silicon single crystal ingot can be produced relatively easily over substantially the entire length.
[Brief description of the drawings]
FIG. 1 is an enlarged sectional view of a portion A in FIG. 4 including a silicon melt convection control device according to a first embodiment of the present invention.
FIG. 2 is a sectional view taken along line BB of FIG. 1;
FIG. 3 is a sectional view taken along line CC of FIG. 1;
FIG. 4 is a longitudinal sectional view of a silicon single crystal pulling apparatus including the control device.
FIG. 5 is a sectional view showing a second embodiment of the present invention and corresponding to FIG. 1;
FIG. 6 is a sectional view taken along line DD of FIG. 5;
FIG. 7 is a sectional view taken along line EE of FIG. 5;
FIG. 8 is a sectional view showing a third embodiment of the present invention and corresponding to FIG. 1;
FIG. 9 is a sectional view taken along line FF of FIG. 8;
FIG. 10 is a sectional view taken along line GG of FIG. 8;
FIG. 11 is a sectional view showing a fourth embodiment of the present invention and corresponding to FIG. 1;
FIG. 12 is a sectional view taken along line HH of FIG. 11;
FIG. 13 is a sectional view taken along line II of FIG. 11;
FIG. 14 is a sectional view showing a fifth embodiment of the present invention and corresponding to FIG. 1;
FIG. 15 is a sectional view showing a sixth embodiment of the present invention and corresponding to FIG. 5;
FIG. 16 is a sectional view showing a seventh embodiment of the present invention and corresponding to FIG. 8;
FIG. 17 is a sectional view showing an eighth embodiment of the present invention and corresponding to FIG. 11;
[Explanation of symbols]
11 chambers
12 Silicon melt
13 Quartz crucible
18 Main heater
25 ingots
26 Solid-liquid interface
36 Heat shield
43, 63, 73, 83 Heat source
44 Auxiliary heater
46,66 thermal conductor
47, 67, 77, 87 Quartz tube
48 Heat insulation material for heat source
49 carbon electrode
64 Laser generation means
78 Insulation member
86 Photoconductor
88 Light shielding member

Claims (7)

チャンバ（１１）内に設けられシリコン融液（１２）が貯留された石英るつぼ（１３）と、前記石英るつぼ（１３）の外周面を包囲し前記シリコン融液（１２）を加熱する主ヒータ（１８）とを備えたシリコン単結晶引上げ装置において、
前記シリコン融液（１２）から引上げられるインゴット（２５）と前記シリコン融液（１２）との固液界面（２６）より下方の前記シリコン融液（１２）中で前記インゴット（２５）下面の中心に向って放熱する熱源（４３，６３，７３，８３）が設けられ、
前記熱源（４３，６３，７３，８３）からの放熱により前記固液界面（２６）が上凸状となるように構成されたことを特徴とするシリコン融液対流制御装置。A quartz crucible (13) provided in the chamber (11) and containing the silicon melt (12); and a main heater (20) surrounding the outer peripheral surface of the quartz crucible (13) and heating the silicon melt (12). 18) a silicon single crystal pulling apparatus comprising:
The center of the lower surface of the ingot (25) in the silicon melt (12) below the solid-liquid interface (26) between the ingot (25) pulled up from the silicon melt (12) and the silicon melt (12) Heat sources (43, 63, 73, 83) that dissipate heat toward
A silicon melt convection control device, wherein the solid-liquid interface (26) is configured to have an upward convex shape by heat radiation from the heat sources (43, 63, 73, 83). シリコン融液（１２）から引上げられるインゴット（２５）の外周面を包囲しかつ下端が前記シリコン融液（１２）表面から間隔をあけて上方に位置するように構成され主ヒータ（１８）からの輻射熱を遮る円筒状の熱遮蔽部材（３６）を更に備え、
熱源（４３）が、前記熱遮蔽部材（３６）下端及び前記シリコン融液（１２）表面間に位置しかつチャンバ（１１）外から配索された一対のカーボン電極（４９，４９）により電力が供給される補助ヒータ（４４）と、前記補助ヒータ（４４）の発した熱を受けこの熱を前記シリコン融液（１２）中の前記インゴット（２５）下方に導き更に前記インゴット（２５）下面の中心に向って放散する熱伝導体（４６）と、前記補助ヒータ（４４）及び前記熱伝導体（４６）の周面を被覆する石英管（４７）と、前記熱伝導体（４６）及び前記石英管（４７）間に充填された熱源用断熱部材（４８）とを有する請求項１記載のシリコン融液対流制御装置。The ingot (25), which is pulled up from the silicon melt (12), is configured so as to surround the outer peripheral surface and to have a lower end located above the silicon melt (12) surface at an interval from the main melt (18). A cylindrical heat shielding member (36) for shielding radiant heat;
A heat source (43) is located between the lower end of the heat shielding member (36) and the surface of the silicon melt (12), and power is supplied by a pair of carbon electrodes (49, 49) routed from outside the chamber (11). Upon receiving the heat generated by the supplied auxiliary heater (44) and the auxiliary heater (44), the heat is guided to the lower side of the ingot (25) in the silicon melt (12), and the lower surface of the ingot (25) is further reduced. A heat conductor (46) radiating toward the center, a quartz tube (47) covering the peripheral surfaces of the auxiliary heater (44) and the heat conductor (46), the heat conductor (46) and the heat conductor (46). 2. The convection control device for silicon melt according to claim 1, further comprising a heat-insulating member for a heat source filled between the quartz tubes. シリコン融液（１２）から引上げられるインゴット（２５）の外周面を包囲しかつ下端が前記シリコン融液（１２）表面から間隔をあけて上方に位置するように構成され主ヒータ（１８）からの輻射熱を遮る円筒状の熱遮蔽部材（３６）を更に備え、
熱源（６３）が、チャンバ（１１）外に設けられレーザ光を発生するレーザ発生手段（６４）と、前記レーザ発生手段（６４）の発したレーザ光を受けて熱に変換しこの熱を前記シリコン融液（１２）中の前記インゴット（２５）下方に導き更に前記インゴット（２５）下面の中心に向って放散する熱伝導体（６６）と、前記熱伝導体（６６）の周面を被覆する石英管（６７）と、前記熱伝導体（６６）及び前記石英管（６７）間に充填された熱源用断熱部材（４８）とを有する請求項１記載のシリコン融液対流制御装置。The ingot (25), which is pulled up from the silicon melt (12), is configured so as to surround the outer peripheral surface and to have a lower end located above the silicon melt (12) surface at an interval from the main melt (18). A cylindrical heat shielding member (36) for shielding radiant heat;
A heat source (63) provided outside the chamber (11) for generating a laser beam; and a laser source (64) for receiving the laser beam emitted from the laser generator (64) and converting the heat into heat. A heat conductor (66) that guides below the ingot (25) in the silicon melt (12) and further diffuses toward the center of the lower surface of the ingot (25), and covers a peripheral surface of the heat conductor (66). 2. The silicon melt convection control device according to claim 1, further comprising: a quartz tube (67) to be heated; and a heat source heat insulating member (48) filled between the heat conductor (66) and the quartz tube (67). シリコン融液（１２）から引上げられるインゴット（２５）の外周面を包囲しかつ下端が前記シリコン融液（１２）表面から間隔をあけて上方に位置するように構成され主ヒータ（１８）からの輻射熱を遮る円筒状の熱遮蔽部材（３６）を更に備え、
熱源（７３）が、前記シリコン融液（１２）中で前記インゴット（２５）下面の中心に対向して設けられかつチャンバ（１１）外から配索された一対のカーボン電極（４９，４９）により電力が供給される補助ヒータ（４４）と、前記シリコン融液（１２）中の前記カーボン電極（４９，４９）及び前記補助ヒータ（４４）を被覆する石英管（７７）と、前記石英管（７７）中の一対のカーボン電極（４９，４９）間に設けられ前記一対のカーボン電極（４９，４９）の接触を阻止する絶縁部材（７８）とを有する請求項１記載のシリコン融液対流制御装置。The ingot (25), which is pulled up from the silicon melt (12), is configured so as to surround the outer peripheral surface and to have a lower end located above the silicon melt (12) surface at an interval from the main melt (18). A cylindrical heat shielding member (36) for shielding radiant heat;
A heat source (73) is provided in the silicon melt (12) by a pair of carbon electrodes (49, 49) provided facing the center of the lower surface of the ingot (25) and routed from outside the chamber (11). An auxiliary heater (44) supplied with electric power, a quartz tube (77) for covering the carbon electrodes (49, 49) and the auxiliary heater (44) in the silicon melt (12), and a quartz tube (77). The convection control of silicon melt according to claim 1, further comprising: an insulating member (78) provided between the pair of carbon electrodes (49, 49) in the (77) to prevent contact of the pair of carbon electrodes (49, 49). apparatus. シリコン融液（１２）から引上げられるインゴット（２５）の外周面を包囲しかつ下端が前記シリコン融液（１２）表面から間隔をあけて上方に位置するように構成され主ヒータ（１８）からの輻射熱を遮る円筒状の熱遮蔽部材（３６）を更に備え、
熱源（８３）が、チャンバ（１１）外に設けられレーザ光を発生するレーザ発生手段（６４）と、前記レーザ発生手段（６４）の発したレーザ光を受けて前記シリコン融液（１２）中の前記インゴット（２５）下方に導き更に前記レーザ光を前記インゴット（２５）下面の中心に向って放散する光伝導体（８６）と、前記光伝導体（８６）の周面を被覆する石英管（８７）と、前記光伝導体（８６）及び前記石英管（８７）間に充填された光遮蔽部材（８８）とを有する請求項１記載のシリコン融液対流制御装置。The ingot (25), which is pulled up from the silicon melt (12), is configured so as to surround the outer peripheral surface and to have a lower end located above the silicon melt (12) surface at an interval from the main melt (18). A cylindrical heat shielding member (36) for shielding radiant heat;
A heat source (83) provided outside the chamber (11) for generating a laser beam; and a laser source (64) for receiving the laser beam emitted from the laser generator (64) to generate a laser beam in the silicon melt (12). A photoconductor (86) for guiding the laser light downward and further radiating the laser light toward the center of the lower surface of the ingot (25); and a quartz tube covering the peripheral surface of the photoconductor (86). The silicon melt convection control device according to claim 1, further comprising a light shielding member (88) filled between the photoconductor (86) and the quartz tube (87). 熱源（４３，６３，７３，８３）が熱遮蔽部材（３６）に対して上下動可能に設けられた請求項２ないし５いずれか１項記載のシリコン融液対流制御装置。The convection control device for silicon melt according to any one of claims 2 to 5, wherein the heat source (43, 63, 73, 83) is provided so as to be vertically movable with respect to the heat shielding member (36). チャンバ（１１）内に設けられた石英るつぼ（１３）にインゴット（２５）を引上げ可能なシリコン融液（１２）を貯留し、前記インゴット（２５）内が格子間シリコン型点欠陥の凝集体及び空孔型点欠陥の凝集体の存在しないパーフェクト領域となる引上げ速度で前記インゴット（２５）を引上げるシリコン単結晶引上げ方法において、
前記インゴット（２５）と前記シリコン融液（１２）との固液界面（２６）より下方の前記シリコン融液（１２）中で熱源（４３，６３，７３，８３）が前記インゴット（２５）下面の中心に向って放熱し、
前記固液界面（２６）が上凸状となるように前記熱源（４３，６３，７３，８３）を制御することを特徴とするシリコン融液対流制御方法。A silicon melt (12) capable of pulling up an ingot (25) is stored in a quartz crucible (13) provided in a chamber (11), and the inside of the ingot (25) is an aggregate of interstitial silicon type point defects and In the silicon single crystal pulling method for pulling up the ingot (25) at a pulling speed which is a perfect region where no aggregate of vacancy type point defects is present,
In the silicon melt (12) below the solid-liquid interface (26) between the ingot (25) and the silicon melt (12), a heat source (43, 63, 73, 83) is provided on the lower surface of the ingot (25). Dissipates heat towards the center of
A silicon melt convection control method, wherein the heat sources (43, 63, 73, 83) are controlled so that the solid-liquid interface (26) is convex upward.
JP2002311100A 2002-10-25 2002-10-25 Apparatus and method for controlling silicon melt convection Pending JP2004143002A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7708830B2 (en) 2003-03-27 2010-05-04 Siltronic Ag Method and device for the production of a silicon single crystal, silicon single crystal, and silicon semiconductor wafers with determined defect distributions
CN103205807A (en) * 2011-12-28 2013-07-17 江苏有能光电科技有限公司 Ingot furnace for preparing quasi-monocrystalline silicon and method of preparing quasi-monocrystalline silicon

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7708830B2 (en) 2003-03-27 2010-05-04 Siltronic Ag Method and device for the production of a silicon single crystal, silicon single crystal, and silicon semiconductor wafers with determined defect distributions
CN103205807A (en) * 2011-12-28 2013-07-17 江苏有能光电科技有限公司 Ingot furnace for preparing quasi-monocrystalline silicon and method of preparing quasi-monocrystalline silicon

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