JP3587231B2

JP3587231B2 - Silicon single crystal pulling device

Info

Publication number: JP3587231B2
Application number: JP01441998A
Authority: JP
Inventors: 純古川; 和浩原田; 健真安井; 洋二鈴木
Original assignee: 三菱住友シリコン株式会社
Priority date: 1998-01-27
Filing date: 1998-01-27
Publication date: 2004-11-10
Anticipated expiration: 2018-01-27
Also published as: JPH11209196A

Description

【０００１】
【発明の属する技術分野】
本発明は、シリコン単結晶棒の引上げて育成する装置に関するものである。
【０００２】
【従来の技術】
従来、この種の装置として、シリコン単結晶棒とるつぼとの間に熱遮蔽治具が配設され、この熱遮蔽治具が輻射熱の温度域における耐熱性を有する黒鉛等の母材と、この母材のシリコン単結晶棒側の面を被覆しかつ母材より輻射率が小さい石英等の被覆材とを有する多層構造に形成された単結晶引上装置が開示されている（特開平８−３２５０９０）。
このように構成された単結晶引上装置では、熱輻射率の大きい母材を、この母材より熱輻射率の小さい被覆材で被覆したので、シリコン単結晶棒へのるつぼ及びヒータの輻射熱の遮断効果を向上できる。この結果、シリコン単結晶棒の冷却の促進による引上げ速度を増大でき、シリコン単結晶棒の生産性を向上できるようになっている。
【０００３】
【発明が解決しようとする課題】
しかし、特開平８−３２５０９０号公報に示された単結晶引上装置では、シリコン融液から引上げられるシリコン単結晶棒中のシリコン融液近傍の温度分布は、シリコン単結晶棒の外周面からの放熱量が多いため、中心部で最も高く外周面に向うに従って次第に低くなり、外周部で急激に低くなる。一方、シリコン単結晶棒の大口径化が進むと、上記シリコン単結晶棒の中心部と外周部との温度差は更に大きくなることが予想される。このため、シリコン単結晶棒中に上記温度差に基づく熱的ストレスが発生するおそれがあった。
【０００４】
本発明の目的は、シリコン融液から引上げ中のシリコン単結晶棒の外周部の急激な温度低下を阻止することにより、シリコン単結晶棒中の熱的ストレスの発生を抑制できるシリコン単結晶の引上げ装置を提供することにある。
本発明の別の目的は、シリコン単結晶棒及び熱遮蔽部材間を流下する不活性ガスが放熱抑制部材の上面に滞留するのを防止でき、また放熱抑制部材の上面から輻射熱が逃げるのを阻止できるシリコン単結晶棒の引上げ装置を提供することにある。
【０００５】
【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、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を加熱するヒータ１８と、シリコン融液１２から引上げられるシリコン単結晶棒２５の外周面を包囲しかつ下端がシリコン融液１２表面から間隔をあけて上方に位置しヒータ１８からの輻射熱を遮る熱遮蔽部材２６とを備えたシリコン単結晶の引上げ装置の改良である。
その特徴ある構成は、熱遮蔽部材２６が直筒状の筒部２６ａを有し、筒部２６ａの下縁に、上方に向うに従って直径が小さくなるように形成されかつシリコン単結晶棒２５からの放熱を抑制するコーン状の放熱抑制部材２７の下縁が連設されたところにある。
【０００６】
従来のシリコン単結晶の引上げ装置では、シリコン融液から引上げられるシリコン単結晶棒中のシリコン融液近傍の温度分布は、中心部で最も高く外周面に向うに従って次第に低くなり、外周部で急激に低くなる。しかし、請求項１に記載されたシリコン単結晶の引上げ装置では、シリコン単結晶棒２５からの放熱は、放熱抑制部材２７によって反射されるか、放熱抑制部材２７が高温のシリコン融液１２によって温度上昇することにより抑制され、シリコン単結晶棒２５の外周部の急激な温度低下を阻止できる。この結果、シリコン単結晶棒２５中の温度分布が中心から外周面に向って略均一になる、即ちシリコン単結晶棒２５中の鉛直方向温度勾配の径方向分布が略均一になるので、シリコン単結晶棒２５中の熱的ストレスの発生を抑制できる。
【０００７】
請求項２に係る発明は、請求項１に係る発明であって、更に図３に示すように、熱遮蔽部材２６の筒部２６ａと放熱抑制部材２７との連設部に所定の間隔をあけて複数の孔８８が形成されたことを特徴とする。
この請求項２に記載されたシリコン単結晶の引上げ装置では、シリコン単結晶棒２５及び熱遮蔽部材６６間を流下する不活性ガスを整流コーン６８によりスムーズにシリコン融液１２及び放熱抑制部材６７間に導くことができるので、放熱抑制部材６７の上面に不活性ガスが滞留することはない。
【０００８】
請求項３に係る発明は、請求項１又は２に係る発明であって、更に図２に示すように、放熱抑制部材２７の下縁を含む水平面に対する放熱抑制部材２７の傾斜角θが８０度以下であることを特徴とする。
この請求項３に記載された放熱抑制部材２７の傾斜角θが８０度を越えると、シリコン融液１２から引上げ中のシリコン単結晶棒２５の外周部の急激な温度低下を抑制する効果が低下する。
【０００９】
請求項４に係る発明は、図４に示すように、熱遮蔽部材２６が直筒状の筒部２６ａを有し、筒部２６ａの下縁に、上方に向うに従って直径が小さくなるように形成されかつシリコン単結晶棒からの放熱を抑制するコーン状の第１コーン部１０７ａの下縁が連設され、この第１コーン部１０７ａの下面に、上方に向うに従って直径が小さくなるように形成された第２コーン部１０７ｂが接続部材１０７ｃを介して取付けられたことを特徴とするシリコン単結晶の引上げ装置である。
この請求項４に記載されたシリコン単結晶の引上げ装置では、放熱抑制部材１０７が二重に形成されるので、放熱抑制部材１０７の反射及び蓄熱効果が高まり、シリコン単結晶棒外周面のうち上記固液界面近傍からの放射熱を効果的に抑制できる。
【００１０】
請求項５に係る発明は、図５に示すように、熱遮蔽部材２６が直筒状の筒部２６ａを有し、筒部２６ａの下縁に、シリコン単結晶棒からの放熱を抑制しかつ水平方向に延びるリング状の水平部１１７ａの外縁が連設され、上方に向うに従って直径が小さくなるように形成されたコーン状の第１コーン部１１７ｂの下縁が筒部２６ａの下縁に連設され、第１コーン部１１７ｂの下面に、上方に向うに従って直径が小さくなるように形成されたコーン状の第２コーン部１１７ｃが接続部材１１７ｄを介して取付けられたことを特徴とするシリコン単結晶の引上げ装置である。
この請求項５に記載されたシリコン単結晶の引上げ装置では、放熱抑制部材１１７が三重に形成されるので、放熱抑制部材１１７の反射及び蓄熱効果が更に高まり、シリコン単結晶棒外周面のうち上記固液界面近傍からの放射熱を更に効果的に抑制できる。
【００１１】
【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１及び図２に示すように、シリコン単結晶の引上げ装置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（図１）。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ヒータ１８により包囲され、このヒータ１８は保温筒１９により包囲される。ヒータ１８は石英るつぼ１３に投入された高純度のシリコン多結晶体を加熱・溶融してシリコン融液１２にする。
【００１２】
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棒２５を引上げるための種結晶２４が取付けられる。
【００１３】
更にチャンバ１１にはこのチャンバ１１のシリコン単結晶棒側に不活性ガスを供給しかつ上記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（図１）。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。
【００１４】
一方、引上げ用モータの出力軸（図示せず）にはロータリエンコーダ（図示せず）が設けられ、るつぼ駆動手段１７には石英るつぼ１３内のシリコン融液１２の重量を検出する重量センサ（図示せず）と、支軸１６の昇降位置を検出するリニヤエンコーダ（図示せず）とが設けられる。ロータリエンコーダ、重量センサ及びリニヤエンコーダの各検出出力はコントローラ（図示せず）の制御入力に接続され、コントローラの制御出力は引上げ手段２２の引上げ用モータ及びるつぼ駆動手段の昇降用モータにそれぞれ接続される。またコントローラにはメモリ（図示せず）が設けられ、このメモリにはロータリエンコーダの検出出力に対するワイヤケーブル２３の巻取り長さ、即ちシリコン単結晶棒２５の引上げ長さが第１マップとして記憶され、重量センサの検出出力に対する石英るつぼ１３内のシリコン融液１２の液面レベルが第２マップとして記憶される。コントローラは重量センサの検出出力に基づいて石英るつぼ１３内のシリコン融液１２の液面を常に一定のレベルに保つように、るつぼ駆動手段１７の昇降用モータを制御するように構成される。
【００１５】
このように構成された本発明のシリコン単結晶の引上げ装置の特徴ある点は、シリコン単結晶棒２５の外周面と石英るつぼ１３の内周面との間にシリコン単結晶棒２５の外周面を包囲する熱遮蔽部材２６が設けられたところにある（図１及び図２）。この熱遮蔽部材２６は直筒状に形成されヒータ１８からの輻射熱を遮る筒部２６ａと、この筒部２６ａ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２６ｂとを有する。上記フランジ部２６ｂを保温筒１９上に載置することにより、筒部２６ａ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２６がチャンバ１１内に固定される。また筒部２６ａの下縁には、上方に向かうに従って直径が小さくなるコーン状の放熱抑制部材２７の下縁が連設される。
【００１６】
この放熱抑制部材２７の傾斜角θ、即ち放熱抑制部材２７の下縁を含む水平面に対する放熱抑制部材２７の傾斜角θは８０度以下、好ましくは２０〜６０度の範囲内に設定される（図２）。放熱抑制部材２７の傾斜角θを８０度以下に限定したのは、シリコン融液１２からの輻射熱にて放熱抑制部材２７を確実に温度上昇させることにより、シリコン単結晶棒２５の径方向の温度勾配の均一性を向上させるためである。また放熱抑制部材２７は熱遮蔽部材２６と一体的に形成されるか、或いは熱遮蔽部材２６と別部材で形成した後に熱遮蔽部材２６にビス又はピン等により固定される。
【００１７】
上記熱遮蔽部材２６及び放熱抑制部材２７はＭｏ（モリブデン），Ｗ（タングステン），Ｃ（カーボン）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ことが好ましい。Ｍｏ又はＷはシリコン単結晶棒２５からの放熱をＭｏ又はＷ自体が反射することによって、Ｃはシリコン融液１２からの輻射熱をＣ自体が蓄熱することによって、シリコン単結晶棒２５の外周部からの放熱を抑制する。Ｃからなる熱遮蔽部材２６及び放熱抑制部材２７は図２の拡大図に示すように、２枚のカーボン板ａ及びｂでフェルト材ｃを挟む積層構造とすれば、シリコン単結晶棒２５の外周部の保温効果が高まり更に好ましい。
【００１８】
このように構成されたシリコン単結晶の引上げ装置の動作を説明する。
従来のシリコン単結晶の引上げ装置では、シリコン単結晶棒をシリコン融液から所定の引上げ速度で引上げると、このシリコン単結晶棒中のシリコン融液近傍の温度分布は、シリコン単結晶棒の外周面からの放熱量が多いため、中心部で最も高く外周面に向うに従って次第に低くなり、外周部で急激に低くなる。
しかし本実施の形態のシリコン単結晶の引上げ装置では、高温のシリコン融液１２からの輻射熱により放熱抑制部材２７の温度が上昇するか、又はシリコン単結晶棒２５からの放熱を放熱抑制部材２７が反射することにより、シリコン単結晶棒２５からの急激な放熱は抑制される。この結果、シリコン単結晶棒２５の外周部の急激な温度低下を阻止できる。従って、シリコン単結晶棒２５中の温度分布が中心から外周面に向って略均一になる、即ちシリコン単結晶棒２５中の鉛直方向の温度勾配の径方向分布が略均一になるので、シリコン単結晶棒２５中の熱的ストレスの発生を抑制でき、スリップ発生や有転位化が改善される。
【００１９】
図３は本発明の第２の実施の形態を示す。
この実施の形態では、熱遮蔽部材２６の筒部２６ａと放熱抑制部材２７との連設部に所定の間隔をあけて複数の孔８８が形成される。上記以外の構成は第１の実施の形態と同一である。
このように構成されたシリコン単結晶の引上げ装置では、放熱抑制部材２７の上面に到来した不活性ガスは孔８８を通って筒部２６ａの外方かつ放熱抑制部材２７の下方に流出するので、不活性ガスが放熱抑制部材２７の上面に滞留することはない。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。
【００２０】
図４は本発明の第３の実施の形態を示す。
この実施の形態では、放熱抑制部材１０７が熱遮蔽部材２６の筒部２６ａの下縁に連設された第１コーン部１０７ａと、この第１コーン部１０７ａの下面に接続部材１０７ｃを介して取付けられた第２コーン部１０７ｂとを有する。第１及び第２コーン部１０７ａ，１０７ｂは上方に向うに従って直径が小さくなるコーン状に形成され、接続部材１０７ｃは円周方向に所定の間隔をあけて複数設けられる。
このように構成されたシリコン単結晶の引上げ装置では、放熱抑制部材１０７が二重に形成されるので、放熱抑制部材１０７の反射及び蓄熱効果が高まり、シリコン単結晶棒外周面のうち上記固液界面近傍からの放射熱を効果的に抑制できる。
【００２１】
図５は本発明の第４の実施の形態を示す。
この実施の形態では、放熱抑制部材１１７がリング状の水平部１１７ａと、この水平部１１７ａの上面に載せられた第１及び第２コーン部１１７ｂ，１１７ｃとを有する。水平部１１７ａは熱遮蔽部材２６の筒部２６ａの下縁に連設され、第１及び第２コーン部１１７ｂ，１１７ｃは上方に向うに従って直径が小さくなるコーン状に形成される。また第１及び第２コーン部１１７ｂ，１１７ｃ間には第１及び第２コーン部１１７ｂ，１１７ｃを上下方向に所定の間隔をあけかつ両コーン部１１７ｂ，１１７ｃを接続するための接続部材１１７ｄが介装され、接続部材１１７ｄは円周方向に所定の間隔をあけて複数設けられる。
このように構成されたシリコン単結晶の引上げ装置では、放熱抑制部材１１７が三重に形成されるので、放熱抑制部材１１７の反射及び蓄熱効果が更に高まり、シリコン単結晶棒外周面のうち上記固液界面近傍からの放射熱を更に効果的に抑制できる。
【００２２】
【実施例】
次に本発明の実施例を比較例とともに詳しく説明する。
＜実施例１＞
図１及び図２に示すようなシリコン単結晶の引上げ装置１０の熱遮蔽部材２６の筒部２６ａの内径及び高さをそれぞれ４７０ｍｍ及び４００ｍｍとし、コーン状の放熱抑制部材２７の下端内径、傾斜角θ及び高さをそれぞれ２５０ｍｍ、３０度及び６５ｍｍとした。また放熱抑制部材２７の下縁とシリコン融液１２との間隔を３５ｍｍとした。なお、上記熱遮蔽部材２６及び放熱抑制部材２７はＭｏにより形成した。このように構成された引上げ装置１０を実施例１とした。
【００２３】
＜比較例１＞
図示しないが熱遮蔽部材の下縁に放熱抑制部材が連設されていないことを除いて、引上げ装置を上記実施例１と同一に構成した。この引上げ装置を比較例１とした。
【００２４】
＜比較試験及び評価＞
実施例１及び比較例１の各引上げ装置にて直径２１０ｍｍのシリコン単結晶棒を６００ｍｍ引上げたときのシリコン単結晶棒中の温度分布を熱伝導解析プログラムにてシミュレーション計算し、比較を行った。シリコン融液表面から高さ１０ｍｍまでのシリコン単結晶棒各部の鉛直方向温度勾配の平均値Ｇと、シリコン融液表面から高さ１０ｍｍまでのシリコン単結晶棒中心の鉛直方向温度勾配の平均値Ｇｃとを求め、シリコン単結晶棒の中心から径方向への距離に対するＧ／Ｇｃの変化を求めた。この結果を図６に示す。
【００２５】
同様にしてシリコン融液表面から高さ３０ｍｍまでのシリコン単結晶棒各部の鉛直方向温度勾配の平均値Ｇと、シリコン融液表面から高さ３０ｍｍまでのシリコン単結晶棒中心の鉛直方向温度勾配の平均値Ｇｃとを求め、シリコン単結晶棒の中心から径方向への距離に対するＧ／Ｇｃの変化を求めた。この結果を図７に示す。
更に同様にしてシリコン融液表面から高さ５０ｍｍまでのシリコン単結晶棒各部の鉛直方向温度勾配の平均値Ｇと、シリコン融液表面から高さ５０ｍｍまでのシリコン単結晶棒中心の鉛直方向温度勾配の平均値Ｇｃとを求め、シリコン単結晶棒の中心から径方向への距離に対するＧ／Ｇｃの変化を求めた。この結果を図８に示す。
【００２６】
図６〜図８より明らかなように、実施例１では比較例１よりＧ／Ｇｃの値がシリコン外周面でも急上昇せずに水平に近くなった、即ち鉛直方向温度勾配の径方向分布が略均一になった。これは実施例１ではシリコン融液からの輻射熱により放熱抑制部材の温度が上昇することにより、シリコン単結晶棒からの急激な放熱が放熱抑制部材により抑制され、シリコン単結晶棒の外周部の急激な温度低下を阻止できたためである。
【００２７】
【発明の効果】
以上述べたように、本発明によれば、熱遮蔽部材が直筒状の筒部を有し、この筒部の下縁に、上方に向うに従って直径が小さくなるコーン状の放熱抑制部材の下縁を連設したので、高温のシリコン融液からの輻射熱により放熱抑制部材の温度が上昇するか、又はシリコン単結晶棒からの放熱が放熱抑制部材で反射されることにより、引上げ中のシリコン単結晶棒の外周面からの放熱が抑制される。この結果、シリコン単結晶棒の外周部の急激な温度低下を阻止できるので、シリコン単結晶棒中の温度分布が中心から外周面に向って略均一になる、即ちシリコン単結晶棒中の鉛直方向の温度勾配の径方向分布が略均一になる。従って、シリコン単結晶棒中の熱ストレスの発生を抑制できるので、スリップ発生や有転位化が改善される。
【００２８】
また熱遮蔽部材の筒部と放熱抑制部材との連設部に所定の間隔をあけて複数の孔を形成すれば、シリコン単結晶棒及び熱遮蔽部材間を流下する不活性ガスを整流コーンによりスムーズにシリコン融液及び放熱抑制部材間に導くことができるので、放熱抑制部材の上面に不活性ガスが滞留することはない。
また放熱抑制部材の下縁を含む水平面に対する放熱抑制部材の傾斜角を８０度以下に設定すれば、シリコン融液からの輻射熱にて放熱抑制部材を確実に温度上昇させることにより、又はシリコン単結晶棒からの放熱を放熱抑制部材で確実に反射させることにより、シリコン単結晶棒の径方向の温度勾配の均一性を更に向上できる。
【００２９】
また熱遮蔽部材が直筒状の筒部を有し、筒部の下縁に、上方に向うに従って直径が小さくなるように形成されかつシリコン単結晶棒からの放熱を抑制するコーン状の第１コーン部の下縁を連設し、この第１コーン部の下面に、上方に向うに従って直径が小さくなるように形成された第２コーン部を接続部材を介して取付ければ、放熱抑制部材が二重に形成されるので、放熱抑制部材の反射及び蓄熱効果が高まり、シリコン単結晶棒外周面のうち上記固液界面近傍からの放射熱を効果的に抑制できる。
更に熱遮蔽部材が直筒状の筒部を有し、筒部の下縁に、シリコン単結晶棒からの放熱を抑制しかつ水平方向に延びるリング状の水平部の外縁を連設し、上方に向うに従って直径が小さくなるように形成されたコーン状の第１コーン部の下縁を筒部の下縁に連設し、第１コーン部の下面に、上方に向うに従って直径が小さくなるように形成されたコーン状の第２コーン部を接続部材を介して取付ければ、放熱抑制部材が三重に形成されるので、放熱抑制部材の反射及び蓄熱効果が更に高まり、シリコン単結晶棒外周面のうち上記固液界面近傍からの放射熱を更に効果的に抑制できる。
【図面の簡単な説明】
【図１】本発明第１実施形態のシリコン単結晶の引上げ装置の断面構成図。
【図２】図１のＡ部拡大断面図。
【図３】本発明の第２実施形態の熱遮蔽部材及び放熱抑制部材の断面構成図。
【図４】本発明の第３実施形態の熱遮蔽部材及び放熱抑制部材の断面構成図。
【図５】本発明の第４実施形態の熱遮蔽部材及び放熱抑制部材の断面構成図。
【図６】シリコン単結晶棒の中心から径方向への距離に対するＧ（シリコン融液表面から高さ１０ｍｍまでのシリコン単結晶棒各部の鉛直方向温度勾配の平均値）／Ｇｃ（シリコン融液表面から高さ１０ｍｍまでのシリコン単結晶棒中心の鉛直方向温度勾配の平均値）の変化を示す図。
【図７】シリコン単結晶棒の中心から径方向への距離に対するＧ（シリコン融液表面から高さ３０ｍｍまでのシリコン単結晶棒各部の鉛直方向温度勾配の平均値）／Ｇｃ（シリコン融液表面から高さ３０ｍｍまでのシリコン単結晶棒中心の鉛直方向温度勾配の平均値）の変化を示す図。
【図８】シリコン単結晶棒の中心から径方向への距離に対するＧ（シリコン融液表面から高さ５０ｍｍまでのシリコン単結晶棒各部の鉛直方向温度勾配の平均値）／Ｇｃ（シリコン融液表面から高さ５０ｍｍまでのシリコン単結晶棒中心の鉛直方向温度勾配の平均値）の変化を示す図。
【符号の説明】
１０シリコン単結晶の引上げ装置
１１チャンバ
１２シリコン融液
１３石英るつぼ
１８ヒータ
２６熱遮蔽部材
２６ａ筒部
２７，１０７，１１７放熱抑制部材
８８複数の孔
１０７ａ，１１７ｂ第１コーン部
１０７ｂ，１１７ｃ第２コーン部
１０７ｃ，１１７ｄ接続部材
１１７ａ水平部 [0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for pulling and growing a silicon single crystal rod.
[0002]
[Prior art]
Conventionally, as this type of apparatus, a heat shielding jig is provided between a silicon single crystal rod and a crucible, and the heat shielding jig is made of a base material such as graphite having heat resistance in a temperature range of radiant heat. There is disclosed a single crystal pulling apparatus formed in a multilayer structure having a coating on the silicon single crystal rod side of the base material and a coating material such as quartz having a lower emissivity than the base material (Japanese Unexamined Patent Application Publication No. Hei 8 (1996) -108). 325090).
In the single crystal pulling apparatus configured as described above, since the base material having a large heat radiation rate is covered with the coating material having a smaller heat radiation rate than this base material, the radiation heat of the crucible and the heater to the silicon single crystal rod is heated. The blocking effect can be improved. As a result, the pulling speed can be increased by promoting the cooling of the silicon single crystal rod, and the productivity of the silicon single crystal rod can be improved.
[0003]
[Problems to be solved by the invention]
However, in the single crystal pulling apparatus disclosed in Japanese Patent Application Laid-Open No. 8-325090, the temperature distribution near the silicon melt in the silicon single crystal rod pulled from the silicon melt is different from the outer peripheral surface of the silicon single crystal rod. Since the amount of heat radiation is large, it becomes highest at the center and gradually decreases toward the outer peripheral surface, and rapidly decreases at the outer peripheral portion. On the other hand, as the diameter of the silicon single crystal rod increases, it is expected that the temperature difference between the central portion and the outer peripheral portion of the silicon single crystal rod further increases. Therefore, thermal stress based on the temperature difference is there is likely to occur in the silicon single crystal rod.
[0004]
SUMMARY OF THE INVENTION It is an object of the present invention to prevent a rapid drop in the temperature of the outer periphery of a silicon single crystal rod during pulling from a silicon melt, thereby suppressing the occurrence of thermal stress in the silicon single crystal rod. It is to provide a device.
Another object of the present invention is to prevent the inert gas flowing between the silicon single crystal rod and the heat shielding member from staying on the upper surface of the heat radiation suppressing member, and prevent radiant heat from escaping from the upper surface of the heat radiation suppressing member. It is an object of the present invention to provide an apparatus for pulling a silicon single crystal rod.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, as shown in FIG. 1, a quartz crucible 13 provided in a chamber 11 and containing a silicon melt 12 and surrounding the outer peripheral surface of the quartz crucible 13 are heated. A heat shield member 26 surrounding the outer peripheral surface of the heater 18 and the silicon single crystal rod 25 pulled up from the silicon melt 12 and having a lower end located above the surface of the silicon melt 12 at an interval and blocking radiant heat from the heater 18. And a silicon single crystal pulling apparatus comprising:
Its characteristic configuration has a heat shield member 26 is a straight cylindrical tubular portion 26a, the lower edge of the cylindrical portion 26a, the heat radiation from the formed and the silicon single crystal rod 25 so that the diameter decreases as directed upward The lower edge of the cone-shaped heat radiation suppressing member 27 for suppressing the heat dissipation is provided continuously.
[0006]
In the conventional silicon single crystal pulling apparatus, the temperature distribution near the silicon melt in the silicon single crystal rod pulled from the silicon melt is highest at the center and gradually decreases toward the outer peripheral surface, and sharply at the outer periphery. Lower. However, in the silicon single crystal pulling apparatus according to the first aspect, the heat radiation from the silicon single crystal rod 25 is reflected by the heat radiation suppressing member 27 or the heat radiation suppressing member 27 is heated by the high temperature silicon melt 12. The temperature is suppressed by the rise, and it is possible to prevent a sharp decrease in the temperature of the outer peripheral portion of the silicon single crystal rod 25. As a result, the temperature distribution in the silicon single crystal rod 25 becomes substantially uniform from the center toward the outer peripheral surface, that is, the radial distribution of the vertical temperature gradient in the silicon single crystal rod 25 becomes substantially uniform. Generation of thermal stress in crystal rod 25 can be suppressed.
[0007]
The invention according to claim 2 is the invention according to claim 1, and furthermore, as shown in FIG. 3, a predetermined interval is provided at a continuous portion between the cylindrical portion 26a of the heat shielding member 26 and the heat radiation suppressing member 27. Thus, a plurality of holes 88 are formed.
In the apparatus for pulling a silicon single crystal according to the second aspect, the inert gas flowing between the silicon single crystal rod 25 and the heat shielding member 66 is smoothly moved between the silicon melt 12 and the heat radiation suppressing member 67 by the rectifying cone 68. Therefore, the inert gas does not stay on the upper surface of the heat dissipation suppressing member 67.
[0008]
The invention according to claim 3 is the invention according to claim 1 or 2 , wherein the inclination angle θ of the heat radiation suppressing member 27 with respect to the horizontal plane including the lower edge of the heat radiation suppressing member 27 is 80 degrees, as shown in FIG. It is characterized by the following.
When the inclination angle θ of the heat radiation suppressing member 27 according to the third aspect exceeds 80 degrees, the effect of suppressing a rapid temperature drop of the outer peripheral portion of the silicon single crystal rod 25 being pulled from the silicon melt 12 is reduced. I do.
[0009]
In the invention according to claim 4, as shown in FIG. 4, the heat shielding member 26 has a cylindrical portion 26a having a straight cylindrical shape, and is formed on the lower edge of the cylindrical portion 26a so that the diameter decreases as it goes upward. A lower edge of the cone-shaped first cone portion 107a that suppresses heat radiation from the silicon single crystal rod is continuously provided, and is formed on the lower surface of the first cone portion 107a so that the diameter decreases as it goes upward. A silicon single crystal pulling apparatus characterized in that the second cone portion 107b is attached via a connecting member 107c.
In the silicon single crystal pulling apparatus according to the fourth aspect, since the heat radiation suppressing member 107 is formed in a double structure, the reflection and heat storage effects of the heat radiation suppressing member 107 are enhanced, and the above-mentioned outer peripheral surface of the silicon single crystal rod is formed. Radiant heat from near the solid-liquid interface can be effectively suppressed.
[0010]
In the invention according to claim 5, as shown in FIG. 5, the heat shielding member 26 has a cylindrical portion 26a having a straight cylindrical shape. An outer edge of a ring-shaped horizontal portion 117a extending in the direction is continuously provided, and a lower edge of a cone-shaped first cone portion 117b formed so as to decrease in diameter as it goes upward is connected to a lower edge of the cylindrical portion 26a. A silicon single crystal, wherein a second cone portion 117c having a cone shape formed so as to decrease in diameter as it goes upward is attached to a lower surface of the first cone portion 117b via a connecting member 117d. The lifting device.
In the silicon single crystal pulling apparatus according to the fifth aspect, since the heat radiation suppressing members 117 are formed in three layers, the reflection and heat storage effects of the heat radiation suppressing members 117 are further enhanced, and the silicon single crystal rod has the above-mentioned outer peripheral surface. Radiant heat from near the solid-liquid interface can be more effectively suppressed.
[0011]
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 FIGS. 1 and 2, a quartz crucible 13 for storing a silicon melt 12 is provided in a chamber 11 of a silicon single crystal pulling apparatus 10, and the outer surface of the quartz crucible 13 is covered with a graphite susceptor 14. Is done. 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 means 17 (FIG. 1). The crucible driving means 17 includes a first rotation motor (not shown) for rotating the quartz crucible 13 and a lifting / lowering motor for raising / lowering the quartz crucible 13, 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 heater 18 at a predetermined interval from the quartz crucible 13, and the heater 18 is surrounded by a heat retaining tube 19. The heater 18 heats and melts the high-purity polycrystalline silicon charged into the quartz crucible 13 to form the silicon melt 12.
[0012]
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 rod 25.
[0013]
Further, the chamber 11 is connected to gas supply / discharge means 28 for supplying an inert gas to the silicon single crystal rod side of the chamber 11 and discharging the inert gas from the inner peripheral side of the crucible of the chamber 11 (FIG. 1). ). 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 provided with first and second flow control valves 31 and 32 for adjusting the flow rate of the inert gas flowing through these pipes 29 and 30, respectively.
[0014]
On the other hand, a rotary encoder (not shown) is provided on an output shaft (not shown) of the pulling motor, and a crucible driving means 17 is a weight sensor (FIG. 1) for detecting the weight of the silicon melt 12 in the quartz crucible 13. (Not shown), and a linear encoder (not shown) for detecting the vertical position of the support shaft 16. Each detection output of the rotary encoder, the weight sensor and the linear encoder is connected to a control input of a controller (not shown), and the control output of the controller is connected to a pulling motor of the pulling means 22 and a lifting motor of the crucible driving means, respectively. You. The controller is provided with a memory (not shown), in which the winding length of the wire cable 23 relative to the detection output of the rotary encoder, that is, the pulling length of the silicon single crystal rod 25 is stored as a first map. The liquid level of the silicon melt 12 in the quartz crucible 13 with respect to the detection output of the weight sensor is stored as a second map. The controller is configured to control the motor for raising and lowering the crucible driving means 17 so that the liquid level of the silicon melt 12 in the quartz crucible 13 is always kept at a constant level based on the detection output of the weight sensor.
[0015]
A feature of the silicon single crystal pulling apparatus of the present invention thus configured is that the outer peripheral surface of the silicon single crystal rod 25 is located between the outer peripheral surface of the silicon single crystal rod 25 and the inner peripheral surface of the quartz crucible 13. This is where the surrounding heat shielding member 26 is provided (FIGS. 1 and 2). The heat shielding member 26 has a cylindrical portion 26a formed in a straight cylindrical shape and shielding radiant heat from the heater 18, and a flange portion 26b connected to an upper edge of the cylindrical portion 26a and extending outward in a substantially horizontal direction. By mounting the flange portion 26b on the heat retaining cylinder 19, the heat shielding member 26 is fixed in the chamber 11 so that the lower edge of the cylindrical portion 26a is located a predetermined distance above the surface of the silicon melt 12. You. Also the lower edge of the cylindrical portion 26a, the lower edge of the cone-like heat radiation reduction member 27 having a diameter toward the upper smaller are continuously provided.
[0016]
The inclination angle θ of the heat radiation suppression member 27, that is, the inclination angle θ of the heat radiation suppression member 27 with respect to the horizontal plane including the lower edge of the heat radiation suppression member 27 is set to 80 degrees or less, preferably in the range of 20 to 60 degrees (FIG. 2). The reason why the inclination angle θ of the heat radiation suppressing member 27 is limited to 80 degrees or less is that the temperature of the heat radiation suppressing member 27 is reliably raised by radiant heat from the silicon melt 12 so that the temperature in the radial direction of the silicon single crystal rod 25 is increased. This is for improving the uniformity of the gradient. Further, the heat radiation suppressing member 27 is formed integrally with the heat shielding member 26, or is formed separately from the heat shielding member 26, and then fixed to the heat shielding member 26 with screws or pins.
[0017]
The heat shielding member 26 and the heat radiation suppressing member 27 are preferably made of Mo (molybdenum), W (tungsten), C (carbon), or graphite whose surface is coated with SiC. Mo or W reflects the heat radiation from the silicon single crystal rod 25 by Mo or W itself, and C stores the radiant heat from the silicon melt 12 by C itself, so that the outer periphery of the silicon single crystal rod 25 Suppresses heat radiation. As shown in the enlarged view of FIG. 2, the heat shielding member 26 and the heat radiation suppressing member 27 made of C have a laminated structure in which a felt material c is sandwiched between two carbon plates a and b. The heat retaining effect of the part is enhanced, which is more preferable.
[0018]
The operation of the silicon single crystal pulling apparatus thus configured will be described.
In a conventional silicon single crystal pulling apparatus, when a silicon single crystal rod is pulled up from a silicon melt at a predetermined pulling speed, the temperature distribution in the vicinity of the silicon melt in the silicon single crystal rod becomes the outer periphery of the silicon single crystal rod. Since the amount of heat radiation from the surface is large, it is highest at the center and gradually decreases toward the outer peripheral surface, and rapidly decreases at the outer peripheral portion.
However, in the silicon single crystal pulling apparatus of the present embodiment, the temperature of the heat radiation suppressing member 27 rises due to the radiant heat from the high-temperature silicon melt 12, or the heat radiation suppressing member 27 reduces the heat radiation from the silicon single crystal rod 25. Due to the reflection, rapid heat radiation from the silicon single crystal rod 25 is suppressed. As a result, it is possible to prevent a sharp drop in the temperature of the outer peripheral portion of the silicon single crystal rod 25. Accordingly, the temperature distribution in the silicon single crystal rod 25 becomes substantially uniform from the center toward the outer peripheral surface, that is, the radial temperature gradient distribution in the silicon single crystal rod 25 becomes substantially uniform. The generation of thermal stress in the crystal rod 25 can be suppressed, and the generation of slip and dislocation are improved.
[0019]
Figure 3 shows a second embodiment of the present invention.
In this embodiment, a plurality of holes 88 are formed at predetermined intervals in a continuous portion between the cylindrical portion 26a of the heat shielding member 26 and the heat radiation suppressing member 27. The configuration other than the above is the same as that of the first embodiment.
In the silicon single crystal pulling apparatus configured as described above, the inert gas arriving at the upper surface of the heat radiation suppressing member 27 flows out of the cylindrical portion 26a and below the heat radiation suppressing member 27 through the hole 88. The inert gas does not stay on the upper surface of the heat radiation suppressing member 27. 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.
[0020]
FIG. 4 shows a third embodiment of the present invention.
In this embodiment, the heat radiation suppressing member 107 is attached to the lower end of the cylindrical portion 26a of the heat shielding member 26 by a first cone portion 107a, and is attached to the lower surface of the first cone portion 107a via a connecting member 107c. And a second cone portion 107b. The first and second cone portions 107a and 107b are formed in a cone shape whose diameter decreases as going upward, and a plurality of connection members 107c are provided at predetermined intervals in the circumferential direction.
In the silicon single crystal pulling apparatus configured as described above, since the heat radiation suppressing member 107 is formed in double, the reflection and heat storage effects of the heat radiation suppressing member 107 are enhanced, and the solid-liquid Radiant heat from near the interface can be effectively suppressed.
[0021]
FIG. 5 shows a fourth embodiment of the present invention.
In this embodiment, the heat radiation suppressing member 117 has a ring-shaped horizontal portion 117a, and first and second cone portions 117b and 117c mounted on the upper surface of the horizontal portion 117a. The horizontal portion 117a is provided continuously with the lower edge of the cylindrical portion 26a of the heat shielding member 26, and the first and second cone portions 117b and 117c are formed in a cone shape whose diameter decreases upward. A connecting member 117d is provided between the first and second cone portions 117b and 117c to keep the first and second cone portions 117b and 117c at predetermined intervals in the vertical direction and to connect the two cone portions 117b and 117c. A plurality of connection members 117d are provided at predetermined intervals in the circumferential direction.
In the silicon single crystal pulling apparatus configured as described above, since the heat radiation suppressing members 117 are formed in three layers, the reflection and heat storage effects of the heat radiation suppressing members 117 are further enhanced, and the solid-liquid portion on the outer peripheral surface of the silicon single crystal rod is formed. the radiant heat from the vicinity of the interface Ru can be further effectively suppressed.
[0022]
【Example】
Next, examples of the present invention will be described in detail together with comparative examples.
<Example 1>
The inner diameter and height of the cylindrical portion 26a of the heat shielding member 26 of the silicon single crystal pulling apparatus 10 as shown in FIGS. 1 and 2 are 470 mm and 400 mm, respectively, and the inner diameter of the lower end of the cone-shaped heat radiation suppressing member 27 and the inclination angle. θ and the height were 250 mm, 30 degrees and 65 mm, respectively. The distance between the lower edge of the heat radiation suppressing member 27 and the silicon melt 12 was 35 mm. The heat shielding member 26 and the heat radiation suppressing member 27 were formed of Mo. The pulling device 10 thus configured was referred to as Example 1.
[0023]
< Comparative Example 1>
Although not shown, the pulling-up device was configured in the same manner as in Example 1 except that the heat radiation suppressing member was not provided continuously at the lower edge of the heat shielding member. This pulling device was designated as Comparative Example 1.
[0024]
<Comparison test and evaluation>
The temperature distribution of the silicon single crystal ingot in the time was 600mm pulled silicon single crystal rod having a diameter of 210mm at the pulling device of the first embodiment 及 beauty Comparative Example 1 and the simulation calculation in the heat conduction analysis program, and compared . The average value G of the vertical temperature gradient of each part of the silicon single crystal rod from the surface of the silicon melt to 10 mm in height and the average value Gc of the vertical temperature gradient of the center of the silicon single crystal rod from the surface of the silicon melt to 10 mm in height And the change in G / Gc with respect to the distance in the radial direction from the center of the silicon single crystal rod was determined. The results are shown in Figure 6.
[0025]
Similarly, the average value G of the vertical temperature gradient of each part of the silicon single crystal rod from the silicon melt surface to a height of 30 mm and the vertical temperature gradient of the silicon single crystal rod center from the silicon melt surface to a height of 30 mm is calculated. The average value Gc was determined, and the change in G / Gc with respect to the distance in the radial direction from the center of the silicon single crystal rod was determined. The results are shown in Figure 7.
Further, similarly, the average value G of the vertical temperature gradient of each portion of the silicon single crystal rod from the surface of the silicon melt to 50 mm in height and the vertical temperature gradient of the center of the silicon single crystal rod from the surface of the silicon melt to 50 mm in height. And the change in G / Gc with respect to the radial distance from the center of the silicon single crystal rod was determined. The results are shown in Figure 8.
[0026]
6 to 8 As is apparent, the value of G / Gc than Comparative Example 1 in Example 1 was horizontally close without spikes in the silicon outer peripheral surface, i.e., the radial direction distribution of vertical temperature gradient It became almost uniform. By the temperature of the heat radiation suppressing member is raised by radiant heat from the silicon melt in this Example 1, a rapid heat dissipation from the silicon single crystal rod is inhibited by the radiation suppressing member, the outer peripheral portion of the silicon single crystal rod Ru der because it was able to prevent the sudden drop in temperature.
[0027]
【The invention's effect】
As described above, according to the present invention, the heat shielding member has a straight cylindrical tubular portion, and the lower edge of the cone-shaped heat radiation suppressing member , the diameter of which decreases toward the upper side, at the lower edge of the tubular portion. , The temperature of the heat dissipation suppressing member rises due to radiant heat from the high-temperature silicon melt, or the heat dissipation from the silicon single crystal rod is reflected by the heat dissipation suppressing member, so that the silicon single crystal being pulled up Heat radiation from the outer peripheral surface of the rod is suppressed. As a result, a sharp drop in the temperature of the outer peripheral portion of the silicon single crystal rod can be prevented, so that the temperature distribution in the silicon single crystal rod becomes substantially uniform from the center toward the outer peripheral surface, that is, in the vertical direction in the silicon single crystal rod. Is substantially uniform in the radial direction of the temperature gradient. Therefore, since the occurrence of thermal stress in the silicon single crystal rod can be suppressed, slip generation and dislocations can be improved.
[0028]
In addition, if a plurality of holes are formed at predetermined intervals in a continuous portion between the cylindrical portion of the heat shielding member and the heat radiation suppressing member, an inert gas flowing between the silicon single crystal rod and the heat shielding member is rectified by a rectifying cone. Since the gas can be smoothly guided between the silicon melt and the heat radiation suppressing member, the inert gas does not stay on the upper surface of the heat radiation suppressing member.
Further, if the inclination angle of the heat dissipation suppressing member with respect to the horizontal plane including the lower edge of the heat dissipation suppressing member is set to 80 degrees or less, the temperature of the heat dissipation suppressing member is surely increased by radiant heat from the silicon melt, or the silicon single crystal By ensuring that the heat radiation from the rod is reflected by the heat radiation suppressing member, the uniformity of the radial temperature gradient of the silicon single crystal rod can be further improved.
[0029]
Also has a heat shielding member is a straight cylindrical tubular portion, the lower edge of the cylindrical portion, the first diameter is smaller Kunar so on are formed and shaped to suppress corn heat radiation from the silicon single crystal rod according directed upwards A lower edge of the cone portion is continuously provided, and a second cone portion formed so as to have a diameter decreasing toward the upper side is attached to a lower surface of the first cone portion via a connecting member. Since it is formed double, the reflection and heat storage effects of the heat radiation suppressing member are enhanced, and radiant heat from the vicinity of the solid-liquid interface on the outer peripheral surface of the silicon single crystal rod can be effectively suppressed.
Further, the heat shielding member has a straight cylindrical tubular portion, and a lower edge of the tubular portion is connected to an outer edge of a ring-shaped horizontal portion extending in the horizontal direction to suppress heat radiation from the silicon single crystal rod and to extend upward. A lower edge of a cone-shaped first cone portion formed so as to have a smaller diameter as it faces is connected to a lower edge of the cylindrical portion, and is formed on the lower surface of the first cone portion such that the diameter decreases as it goes upward. If the formed cone-shaped second cone portion is attached via a connecting member, the heat dissipation suppressing member is formed in triple, so that the reflection and heat storage effects of the heat dissipation suppressing member are further enhanced, and the outer peripheral surface of the silicon single crystal rod is formed. The radiation heat from the vicinity of the solid-liquid interface can be more effectively suppressed.
[Brief description of the drawings]
FIG. 1 is a sectional configuration view of a silicon single crystal pulling apparatus according to a first embodiment of the present invention.
FIG. 2 is an enlarged sectional view of a portion A in FIG.
FIG. 3 is a sectional configuration diagram of a heat shielding member and a heat radiation suppressing member according to a second embodiment of the present invention.
FIG. 4 is a sectional configuration diagram of a heat shielding member and a heat radiation suppressing member according to a third embodiment of the present invention.
FIG. 5 is a sectional configuration diagram of a heat shielding member and a heat radiation suppressing member according to a fourth embodiment of the present invention.
FIG. 6 : G (average value of vertical temperature gradient of each portion of silicon single crystal rod from silicon melt surface to height of 10 mm) / Gc (silicon melt surface) with respect to distance from center of silicon single crystal rod to radial direction FIG. 5 is a graph showing a change in the vertical temperature gradient at the center of the silicon single crystal rod from the center to the height of 10 mm.
FIG. 7 : G (average value of vertical temperature gradient of each part of silicon single crystal rod from silicon melt surface to height 30 mm) / Gc (silicon melt surface) with respect to distance in the radial direction from the center of silicon single crystal rod FIG. 7 is a diagram showing a change in the vertical temperature gradient at the center of the silicon single crystal rod from the height to 30 mm.
FIG. 8 : G (average value of vertical temperature gradient of each part of silicon single crystal rod from the surface of silicon melt to 50 mm in height) / Gc (surface of silicon melt) with respect to distance from center of silicon single crystal rod to radial direction FIG. 5 is a graph showing a change in the vertical temperature gradient at the center of the silicon single crystal rod from the height of the silicon single crystal rod to the height of 50 mm.
[Explanation of symbols]
Reference Signs List 10 silicon single crystal pulling apparatus 11 chamber 12 silicon melt 13 quartz crucible 18 heater 2 6 heat shielding member
26a cylindrical portion 27 , 107 , 117 heat dissipation suppressing member
88 multiple holes
107a, 117b First cone section
107b, 117c Second cone part
107c, 117d connection member
117a Horizontal section

Claims

A quartz crucible (13) provided in a chamber (11) and containing a silicon melt (12), and a heater (18) surrounding the outer peripheral surface of the quartz crucible (13) and heating the silicon melt (12) ), And surrounds the outer peripheral surface of the silicon single crystal rod (25) pulled up from the silicon melt (12), and has a lower end located above the silicon melt (12) surface at an interval from the surface of the silicon melt (12). In a silicon single crystal pulling device equipped with a heat shielding member (26) for shielding radiant heat from
The heat shielding member (26) has a straight tubular portion (26a) ,
A lower edge of the cone-shaped heat radiation suppressing member ( 27 ) , which is formed on a lower edge of the cylindrical portion (26a) so as to decrease in diameter as it goes upward and suppresses heat radiation from the silicon single crystal rod (25). A silicon single crystal pulling apparatus, wherein

Heat shielding member (26) Tube part (26a) And heat dissipation suppressing member (27) Multiple holes at predetermined intervals (88) 2. The apparatus for pulling a silicon single crystal according to claim 1, wherein:

Pulling apparatus of a silicon single crystal of the heat radiation suppressing member (27) tilt angle according to claim 1 or 2, wherein less than 80 degrees relative to a horizontal plane containing the lower edge of the heat radiation suppressing member (27).

A quartz crucible provided in a chamber and containing a silicon melt, a heater surrounding the outer peripheral surface of the quartz crucible and heating the silicon melt, and an outer peripheral surface of a silicon single crystal rod pulled up from the silicon melt. A heat shielding member surrounding and having a lower end located above the silicon melt surface at an interval from the surface of the silicon melt and shielding radiant heat from the heater; (26) In a silicon single crystal pulling apparatus having
The heat shielding member (26) Is a straight cylinder (26a) Has,
The cylinder (26a) A first cone portion formed at the lower edge of the first cone portion so as to decrease in diameter as going upward, and to suppress heat radiation from the silicon single crystal rod. (107a) The lower edge of the
This first cone (107a) A second cone portion formed on the lower surface of the second member so that the diameter decreases as going upward. (107b) Is the connection member (107c) Mounted via
An apparatus for pulling a silicon single crystal.

A quartz crucible provided in a chamber and containing a silicon melt, a heater surrounding the outer peripheral surface of the quartz crucible and heating the silicon melt, and an outer peripheral surface of a silicon single crystal rod pulled up from the silicon melt. A heat shielding member surrounding and having a lower end located above the silicon melt surface at an interval from the surface of the silicon melt and shielding radiant heat from the heater; (26) In a silicon single crystal pulling apparatus having
The heat shielding member (26) Is a straight cylinder (26a) Has,
The cylinder (26a) A ring-shaped horizontal portion that suppresses heat radiation from the silicon single crystal bar and extends horizontally (117a) The outer edge of
A cone-shaped first cone portion formed so that its diameter decreases as it goes upward. (117b) The lower edge of the cylinder (26a) Is connected to the lower edge of
The first cone portion (117b) A second cone portion formed on the lower surface of the second member so that the diameter thereof decreases as going upward. (117c) Is the connection member (117d) Mounted via
An apparatus for pulling a silicon single crystal.