JP2003002783A - Method for producing silicon single crystal - Google Patents
Method for producing silicon single crystalInfo
- Publication number
- JP2003002783A JP2003002783A JP2001181583A JP2001181583A JP2003002783A JP 2003002783 A JP2003002783 A JP 2003002783A JP 2001181583 A JP2001181583 A JP 2001181583A JP 2001181583 A JP2001181583 A JP 2001181583A JP 2003002783 A JP2003002783 A JP 2003002783A
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- JP
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- Prior art keywords
- ingot
- magnetic field
- cusp magnetic
- quartz crucible
- controlled
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、シリコン単結晶を
シリコン融液から引上げて製造するときに、シリコン融
液にカスプ（ＣＵＳＰ）磁場を印加しながらシリコン単
結晶を製造する方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a silicon single crystal while pulling a silicon single crystal from a silicon melt and applying a cusp (CUSP) magnetic field to the silicon melt. .
【０００２】[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。2. Description of the Related Art Conventionally, as a method of manufacturing a silicon single crystal, a method of pulling an ingot of a silicon single crystal by the Czochralski method (hereinafter referred to as the CZ method) is known. This CZ method is a method for producing a columnar silicon single crystal ingot by bringing a seed crystal into contact with a silicon melt stored in a quartz crucible and pulling the seed crystal while rotating the quartz crucible and the seed crystal. Is.
【０００３】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（Inters
titial-type Large Dislocation、以下、ＬＤ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。On the other hand, in the process of manufacturing a semiconductor integrated circuit, microdefects of oxygen precipitates, which are cores of oxidation-induced stacking faults (hereinafter referred to as OSFs), and crystals are caused as a cause of lowering the yield. Originated Particles (Crystal Originated Particle,
Hereinafter referred to as COP. ) Or interstitial dislocation (Inters
titial-type Large Dislocation, hereinafter referred to as LD. ) Is listed. Small defects that become nuclei of the OSF are introduced during crystal growth, and are manifested in a thermal oxidation step or the like when manufacturing a semiconductor device, which causes a defect such as an increase in leak current of the manufactured device. Also COP
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 the wafer is measured with a particle counter, the pits are also detected as light scattering defects together with the original particles.
【０００４】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 Breakdo
wn、ＴＤＤＢ）、酸化膜耐圧特性（Time Zero Dielectr
icBreakdown、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ＬＤ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ＬＤを減少させることが必要とな
っている。This COP has an electrical characteristic, for example, a time-dependent dielectric breakdown characteristic of an oxide film.
wn, TDDB), oxide film breakdown voltage characteristics (Time Zero Dielectr
icBreakdown, TZDB), etc.
Further, if the COP exists on the wafer surface, a step may be generated in the device wiring process, which may cause disconnection. Then, the element isolation portion also causes a leak or the like, which lowers the product yield. Further, the LD is also called a dislocation cluster, or a dislocation pit because a pit is formed 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, there is a need to reduce OSF, COP and LD from silicon wafers used to manufacture semiconductor integrated circuits.
【０００５】このＯＳＦ、ＣＯＰ及びＬＤ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を製造できるようになってい
る。A method for manufacturing a silicon single crystal ingot for cutting out a defect-free silicon wafer having no OSF, COP, and LD is disclosed in Japanese Patent Application Laid-Open No. 11-1393. Generally, when a silicon single crystal ingot is pulled at a high speed, a region [V] in which agglomerates of vacancy type point defects are predominantly present inside the ingot is formed,
When the ingot is pulled at a slow speed, a region [I] in which agglomerates of interstitial silicon type point defects are predominantly present inside the ingot is formed. Therefore, in the above-described manufacturing method, the ingot is pulled up at an optimum pulling rate to obtain a perfect region [P] in which the agglomerates of the point defects do not exist.
It is possible to manufacture a silicon single crystal made of.
【０００６】[0006]
【発明が解決しようとする課題】しかし、上記従来の特
開平１１−１３９３号公報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の面内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。本
発明の目的は、インゴットの引上げ速度を厳密に制御し
なくても、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、シリコン単結晶の製造方
法を提供することにある。However, in the method for producing a silicon single crystal ingot disclosed in the above-mentioned Japanese Patent Laid-Open No. 11-1393, the surface of the solid-liquid interface between the silicon single crystal ingot and the silicon melt is solved. It is necessary to control so that the temperature gradient in the vertical direction inside the chamber is uniform, and this control is affected by changes in the remaining amount of silicon melt and changes in convection, so there is no control over the entire length of the straight body of the ingot. It has been difficult to produce defective silicon single crystals. An object of the present invention is to provide a method for producing a silicon single crystal, which can relatively easily produce a defect-free and high-quality silicon single crystal ingot without strictly controlling the pulling rate of the ingot. .
【０００７】[0007]
【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、シリコン単結晶のインゴット１７を
引上げるためのシリコン融液１４を石英るつぼ１３に貯
留し、この石英るつぼの外径より大きなコイル直径を有
する第１及び第２コイル１１，１２を石英るつぼ１３の
回転軸をそれぞれコイル中心としかつ鉛直方向に所定の
間隔をあけて配設し、第１及び第２コイル１１，１２に
互いに逆向きの電流を流すことにより第１及び第２コイ
ルの各コイル中心から第１及び第２コイル間の水平面で
ある中立面１６ａを通るカスプ磁場１６が発生し、カス
プ磁場の中立面とシリコン融液１４の表面との距離を石
英るつぼ１３の内径に対して所定の割合となるように制
御し、カスプ磁場１６の強度が一定となるように制御
し、上記インゴット１７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上記インゴット１７を引上
げるシリコン単結晶の製造方法の改良である。その特徴
ある構成は、石英るつぼ１３の内径をＤとするとき、カ
スプ磁場１６の中立面１６ａをシリコン融液１４の表面
から０．２０Ｄ〜Ｄ下がった位置になるように制御し、
カスプ磁場１６の中立面１６ａ上であって石英るつぼ１
３の回転軸との交点から半径方向に３００ｍｍ離れた円
周上でのカスプ磁場１６の水平方向の強度が５０〜３０
０ガウスの範囲内の一定値となるように制御するところ
にある。The invention according to claim 1 is
As shown in FIG. 1, a silicon melt 14 for pulling up a silicon single crystal ingot 17 is stored in a quartz crucible 13, and first and second coils 11 having a coil diameter larger than the outer diameter of the quartz crucible, 12 are arranged with the rotation axes of the quartz crucible 13 as coil centers and at predetermined intervals in the vertical direction, and the first and second coils 11 and 12 are supplied with currents in opposite directions to each other. A cusp magnetic field 16 is generated from the center of each coil of the two coils and passes through a neutral surface 16a which is a horizontal plane between the first and second coils, and the distance between the neutral surface of the cusp magnetic field and the surface of the silicon melt 14 is set to the quartz crucible. The inside of the ingot 17 is controlled to have a predetermined ratio with respect to the inner diameter of 13 and the strength of the cusp magnetic field 16 is kept constant. In pulling rate to be nonexistent perfect region of the aggregate of the Recessed is an improvement of a method for manufacturing a pulling Ru silicon single crystal the ingot 17. The characteristic configuration is such that, when the inner diameter of the quartz crucible 13 is D, the neutral surface 16a of the cusp magnetic field 16 is controlled to be at a position lower than the surface of the silicon melt 14 by 0.20 D to D,
On the neutral surface 16a of the cusp magnetic field 16 and in the quartz crucible 1
The horizontal strength of the cusp magnetic field 16 on the circumference 300 mm away from the intersection with the axis of rotation 3 is 50 to 30.
The control is performed so that the value becomes a constant value within the range of 0 Gauss.
【０００８】この請求項１に記載されたシリコン単結晶
の製造方法では、カスプ磁場１６の中立面１６ａの位置
及びカスプ磁場１６の強度を上記の範囲で制御しなが
ら、シリコン単結晶のインゴット１７を引上げると、シ
リコン融液１４に所定の対流１４ａ，１４ｂが発生する
ため、インゴット１７中心直下の熱は比較的高く保持さ
れて、固液界面１９が下方に突出する割合が小さくな
る。一方、インゴット１７内がパーフェクト領域となる
インゴットの引上げ速度の許容範囲は、上記対流１４
ａ，１４ｂの変化により固液界面１６ａの面内での鉛直
方向の温度勾配が均一になる、即ちパーフェクト領域と
なる引上げ速度の面内均一性が向上するという理由によ
り広くなるため、インゴットの引上げ速度の制御が比較
的容易になる。この結果、インゴットの引上げ速度を厳
密に制御しなくても、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。In the method for producing a silicon single crystal according to the present invention, the position of the neutral surface 16a of the cusp magnetic field 16 and the strength of the cusp magnetic field 16 are controlled within the above range while the silicon single crystal ingot 17 is controlled. As the predetermined convections 14a and 14b are generated in the silicon melt 14 when the temperature is raised, the heat immediately below the center of the ingot 17 is kept relatively high, and the proportion of the solid-liquid interface 19 protruding downward becomes small. On the other hand, the allowable range of the pulling speed of the ingot in which the inside of the ingot 17 is the perfect region is the above-mentioned convection 14
Since the temperature gradient in the vertical direction in the surface of the solid-liquid interface 16a becomes uniform due to the change of a and 14b, that is, the temperature becomes wide for the reason that the in-plane uniformity of the pulling speed which is a perfect region is improved, and therefore the pulling of the ingot is increased. Speed control is relatively easy. As a result, a defect-free, high-quality silicon single crystal ingot can be relatively easily manufactured without strictly controlling the pulling speed of the ingot.
【０００９】また上記インゴットの直径が２００ｍｍで
あって、石英るつぼの内径Ｄが６００ｍｍであるとき
に、カスプ磁場の中立面をシリコン融液の表面から１２
０〜６００ｍｍ下がった位置になるように制御し、カス
プ磁場１６の中立面１６ａ上であって石英るつぼ１３の
回転軸との交点から半径方向に３００ｍｍ離れた円周上
でのカスプ磁場１６の水平方向の強度が５０〜３００ガ
ウスの範囲内の一定値となるように制御することが好ま
しい。更に上記インゴットの直径が３００ｍｍであっ
て、石英るつぼの内径Ｄが８００ｍｍであるときに、カ
スプ磁場の中立面をシリコン融液の表面から１６０〜８
００ｍｍ下がった位置になるように制御し、カスプ磁場
１６の中立面１６ａ上であって石英るつぼ１３の回転軸
との交点から半径方向に３００ｍｍ離れた円周上でのカ
スプ磁場１６の水平方向の強度が５０〜３００ガウスの
範囲内の一定値となるように制御することができる。When the diameter of the ingot is 200 mm and the inner diameter D of the quartz crucible is 600 mm, the neutral surface of the cusp magnetic field is 12 mm from the surface of the silicon melt.
The cusp magnetic field 16 is controlled so that the position is lowered by 0 to 600 mm, and the cusp magnetic field 16 is on the neutral surface 16a of the cusp magnetic field 16 and is 300 mm radially away from the intersection with the rotation axis of the quartz crucible 13. It is preferable to control the intensity in the horizontal direction to be a constant value within the range of 50 to 300 Gauss. Further, when the diameter of the ingot is 300 mm and the inner diameter D of the quartz crucible is 800 mm, the neutral surface of the cusp magnetic field is 160 to 8 from the surface of the silicon melt.
The cusp magnetic field 16 is controlled so that the position is lowered by 00 mm, and the cusp magnetic field 16 is on the neutral surface 16a of the cusp magnetic field 16 in the horizontal direction at a distance of 300 mm in the radial direction from the intersection with the rotation axis of the quartz crucible 13. Can be controlled to have a constant value within the range of 50 to 300 Gauss.
【００１０】請求項４に係る発明は、図１及び図３に示
すように、インゴット１７を引上げる前のシリコン融液
１４の重量に対する、シリコン融液１４から引上げられ
るインゴット１７の重量の割合である固化率が５０〜１
００％の範囲内であるときに、カスプ磁場１６の中立面
１６ａの位置と、カスプ磁場１６の中立面１６ａ上であ
って石英るつぼ１３の回転軸との交点から半径方向に３
００ｍｍ離れた円周上でのカスプ磁場１６の水平方向の
強度とを請求項１ないし３いずれか記載の範囲でそれぞ
れ制御するシリコン単結晶の製造方法である。この請求
項４に記載されたシリコン単結晶の製造方法では、イン
ゴット１７のボトム１７ｂ側の引上げ時であっても、固
液界面１９の下方に突出する割合が小さくなって固液界
面が平面に近い形状が保たれるため、パーフェクト領域
となるインゴット１７の引上げ速度の許容範囲は殆ど減
少しない。この結果、シリコン単結晶のインゴットの直
胴部の大部分が無欠陥で高品質となる。In the invention according to claim 4, as shown in FIGS. 1 and 3, the ratio of the weight of the ingot 17 pulled up from the silicon melt 14 to the weight of the silicon melt 14 before the ingot 17 is pulled up. Some solidification rate is 50-1
When it is within the range of 00%, the position of the neutral surface 16a of the cusp magnetic field 16 and the position of the neutral point 16a on the cusp magnetic field 16 and the intersection point with the rotation axis of the quartz crucible 13 are 3 in the radial direction.
A method for producing a silicon single crystal, wherein the strength of the cusp magnetic field 16 in the horizontal direction on the circumference at a distance of 00 mm is controlled within the range according to any one of claims 1 to 3. In the method for producing a silicon single crystal according to the fourth aspect, even when the ingot 17 is pulled up to the bottom 17b side, the proportion of protrusion below the solid-liquid interface 19 becomes small and the solid-liquid interface becomes flat. Since the close shape is maintained, the allowable range of the pulling speed of the ingot 17, which is the perfect region, hardly decreases. As a result, most of the straight body of the silicon single crystal ingot is defect-free and of high quality.
【００１１】[0011]
【発明の実施の形態】次に本発明の実施の形態を図面に
基づいて説明する。図１に示すように、本発明のシリコ
ン単結晶の製造方法は、石英るつぼ１３に貯留されたシ
リコン融液１４に第１及び第２コイル１１，１２を用い
てカスプ磁場１６を印加しながら、このシリコン融液１
４からシリコン単結晶のインゴット１７を引上げる方法
である。上記第１及び第２コイル１１，１２は、石英る
つぼ１３の外径より大きなコイル直径を有し、石英るつ
ぼ１３の回転軸をそれぞれコイル中心としかつ鉛直方向
に所定の間隔をあけて配設される。また第１及び第２コ
イル１１，１２には互いに逆向きの電流が流され、これ
により第１及び第２コイルの各コイル中心から第１及び
第２コイル間の水平面である中立面１６ａを通るカスプ
磁場１６が発生するようになっている。なお、図１の符
号１８は石英るつぼ１３の外周面を包囲するヒータであ
る。DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, according to the method for producing a silicon single crystal of the present invention, while applying a cusp magnetic field 16 to the silicon melt 14 stored in the quartz crucible 13 using the first and second coils 11 and 12, This silicon melt 1
This is a method of pulling the silicon single crystal ingot 17 from No. 4. The first and second coils 11 and 12 have a coil diameter larger than the outer diameter of the quartz crucible 13, and are arranged with the rotation axis of the quartz crucible 13 as the coil center and at a predetermined interval in the vertical direction. It In addition, currents in opposite directions are applied to the first and second coils 11 and 12, whereby the neutral plane 16a, which is a horizontal plane between the first and second coils, extends from the center of each coil of the first and second coils. A passing cusp magnetic field 16 is generated. Reference numeral 18 in FIG. 1 is a heater that surrounds the outer peripheral surface of the quartz crucible 13.
【００１２】一方、上記インゴット１７は、このインゴ
ット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
げ速度で引上げられる。即ち、インゴット１７は、ＣＺ
法によりホットゾーン炉内のシリコン融液１４からボロ
ンコフ（Voronkov）の理論に基づいた所定の引上げ速度
プロファイルで引上げられる。On the other hand, the ingot 17 is pulled at a pulling rate such that the inside of the ingot 17 is a perfect region where the agglomerates of interstitial silicon type point defects and the agglomerates of vacancy type point defects do not exist. That is, the ingot 17 is CZ
Method, the silicon melt 14 in the hot zone furnace is pulled up with a predetermined pulling speed profile based on Voronkov's theory.
【００１３】一般的に、ＣＺ法によりホットゾーン炉内
のシリコン融液１４からシリコン単結晶のインゴット１
７を引上げると、インゴット内には、点欠陥（point de
fect）と点欠陥の凝集体（agglomerates：三次元欠陥）
が発生する。点欠陥は空孔型点欠陥と格子間シリコン型
点欠陥という二つの一般的な形態がある。空孔型点欠陥
は一つのシリコン原子がシリコン結晶格子で正常的な位
置の一つから離脱したものである。このような空孔が空
孔型点欠陥になる。一方、原子がシリコン結晶の格子点
以外の位置（インタースチシャルサイト）で発見される
とこれが格子間シリコン点欠陥になる。Generally, a silicon single crystal ingot 1 is produced from a silicon melt 14 in a hot zone furnace by the CZ method.
When 7 is pulled up, a point defect (point de
fect) and point defects agglomerates (three-dimensional defects)
Occurs. There are two general types of point defects: vacancy type point defects and interstitial silicon type point defects. A vacancy type point defect is a defect in which one silicon atom is separated from one of normal positions in the silicon crystal lattice. Such holes become hole-type point defects. On the other hand, when an atom is found at a position (interstitial site) other than the lattice point of the silicon crystal, this becomes an interstitial silicon point defect.
【００１４】点欠陥は一般的にシリコン融液１４とイン
ゴット１７の間の接触面、即ち固液界面１９で形成され
る。しかし、インゴット１７を継続的に引上げることに
よって固液界面１９であった部分は引上げとともに冷却
し始める。冷却の間、空孔型点欠陥又は格子間シリコン
型点欠陥は拡散により互いに合併して、空孔型点欠陥の
凝集体（vacancy agglomerates）又は格子間シリコン型
点欠陥の凝集体（interstitial agglomerates）が形成
される。言い換えれば、凝集体は点欠陥の合併に起因し
て発生する三次元構造となる。Point defects are generally formed at the contact surface between the silicon melt 14 and the ingot 17, that is, at the solid-liquid interface 19. However, by continuously pulling up the ingot 17, the portion that was the solid-liquid interface 19 begins to be cooled along with pulling up. During cooling, vacancy type point defects or interstitial silicon type point defects merge with each other by diffusion to form vacancy agglomerates or interstitial silicon type point defect agglomerates. Is formed. In other words, the aggregate has a three-dimensional structure generated due to the merger of point defects.
【００１５】空孔型点欠陥の凝集体は、前述したＣＯＰ
の他に、ＬＳＴＤ（Laser Scattering Tomograph Defec
ts）又はＦＰＤ（Flow Pattern Defects）と呼ばれる欠
陥を含み、格子間シリコン型点欠陥の凝集体は前述した
ＬＤと呼ばれる欠陥を含む。ＦＰＤとは、インゴットを
スライスして作製されたシリコンウェーハを３０分間セ
コエッチング（Secco etching、ＨＦ：Ｋ2Ｃｒ2Ｏ7(0.1
5mol/l)＝２：１の混合液によるエッチング）したとき
に現れる特異なフローパターンを呈する痕跡の源であ
り、ＬＳＴＤとは、シリコン単結晶内に赤外線を照射し
たときにシリコンとは異なる屈折率を有し散乱光を発生
する源である。The agglomerates of vacancy type point defects are the above-mentioned COPs.
In addition to LSTD (Laser Scattering Tomograph Defec
ts) or FPD (Flow Pattern Defects), and the agglomerates of interstitial silicon type point defects include the above-mentioned defects called LD. FPD means Secco etching (HF: K 2 Cr 2 O 7 (0.1) for 30 minutes on a silicon wafer produced by slicing an ingot.
5mol / l) = 2: 1 mixed solution), which is a source of traces that exhibit a unique flow pattern, and LSTD is a refraction different from silicon when infrared rays are radiated into a silicon single crystal. It is a source that generates scattered light with a certain rate.
【００１６】ボロンコフの理論は、欠陥の数が少ない高
純度インゴット１７を成長させるために、インゴットの
引上げ速度をＶ（ｍｍ／分）、インゴットとシリコン融
液１４の界面近傍のインゴット中の温度勾配をＧ（℃／
ｍｍ）とするときに、Ｖ／Ｇ（ｍｍ2／分・℃）を制御
することである。この理論では、図２に示すように、Ｖ
／Ｇを横軸にとり、空孔型点欠陥濃度と格子間シリコン
型点欠陥濃度を同一の縦軸にとって、Ｖ／Ｇと点欠陥濃
度との関係を図式的に表現し、空孔領域と格子間シリコ
ン領域の境界がＶ／Ｇによって決定されることを説明し
ている。より詳しくは、Ｖ／Ｇ比が臨界点以上では空孔
型点欠陥濃度が優勢なインゴットが形成される反面、Ｖ
／Ｇ比が臨界点以下では格子間シリコン型点欠陥濃度が
優勢なインゴットが形成される。図２において、［Ｉ］
は格子間シリコン型点欠陥が支配的であって、格子間シ
リコン型点欠陥の凝集体が存在する領域（(Ｖ／Ｇ)1以
下）を示し、［Ｖ］はインゴット内での空孔型点欠陥が
支配的であって、空孔型点欠陥の凝集体が存在する領域
（(Ｖ／Ｇ)2以上）を示し、［Ｐ］は空孔型点欠陥の凝
集体及び格子間シリコン型点欠陥の凝集体が存在しない
パーフェクト領域（(Ｖ／Ｇ)1〜(Ｖ／Ｇ)2）を示す。領
域［Ｐ］に隣接する領域［Ｖ］にはＯＳＦ核を形成する
領域［ＯＳＦ］（(Ｖ／Ｇ)2〜(Ｖ／Ｇ)3）が存在する。According to Boronkov's theory, in order to grow a high-purity ingot 17 having a small number of defects, the pulling rate of the ingot is V (mm / min), and a temperature gradient in the ingot near the interface between the ingot and the silicon melt 14 is used. To G (° C /
mm), V / G (mm 2 / min · ° C.) is controlled. In this theory, as shown in FIG.
/ G on the horizontal axis and the vacancy type point defect concentration and the interstitial silicon type point defect concentration on the same vertical axis, the relationship between V / G and the point defect concentration is represented graphically to show the vacancy region and the lattice point. It is explained that the boundary of the inter-silicon region is determined by V / G. More specifically, when the V / G ratio is equal to or higher than the critical point, an ingot having a predominant concentration of vacancy-type point defects is formed, while V
When the / G ratio is below the critical point, an ingot in which the interstitial silicon type point defect concentration is dominant is formed. In FIG. 2, [I]
Indicates a region ((V / G) 1 or less) where interstitial silicon type point defects are predominant and in which agglomerates of interstitial silicon type point defects exist, and [V] is a vacancy type in the ingot. A region ((V / G) 2 or more) in which point defects are dominant and agglomerates of vacancy type point defects are present, and [P] is an agglomerate of vacancy type point defects and interstitial silicon type A perfect region ((V / G) 1 to (V / G) 2 ) where no point defect aggregates are present is shown. The region [V] adjacent to the region [P] has a region [OSF] ((V / G) 2 to (V / G) 3 ) that forms an OSF nucleus.
【００１７】このパーフェクト領域［Ｐ］は更に領域
［ＰI］と領域［ＰV］に分類される。［ＰI］はＶ／Ｇ
比が上記(Ｖ／Ｇ)1から臨界点までの領域であり、
［ＰV］はＶ／Ｇ比が臨界点から上記(Ｖ／Ｇ)2までの領
域である。即ち、［ＰI］は領域［Ｉ］に隣接し、かつ
侵入型転位を形成し得る最低の格子間シリコン型点欠陥
濃度未満の格子間シリコン型点欠陥濃度を有する領域で
あり、［ＰV］は領域［Ｖ］に隣接し、かつＯＳＦを形
成し得る最低の空孔型点欠陥濃度未満の空孔型点欠陥濃
度を有する領域である。なお、上記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。This perfect area [P] is further classified into an area [P I ] and an area [P V ]. [P I ] is V / G
The ratio is the region from (V / G) 1 to the critical point,
[P V ] is the region where the V / G ratio is from the critical point to the above (V / G) 2 . That is, [P I ] is a region adjacent to the region [I] and having an interstitial silicon type point defect concentration lower than the lowest interstitial silicon type point defect concentration capable of forming interstitial dislocations, and [P V] ] Is a region adjacent to the region [V] and having a vacancy type point defect concentration less than the minimum vacancy type point defect concentration capable of forming an OSF. It should be noted that, in the above OSF, a microdefect serving as a nucleus of the OSF is introduced during crystal growth, which becomes apparent in a thermal oxidation step or the like in manufacturing a semiconductor device, and causes a defect such as an increase in leak current of the manufactured device.
【００１８】図１に戻って、カスプ磁場１６の中立面１
６ａとシリコン融液１４の表面との距離を石英るつぼ１
３の内径に対して所定の割合となるように制御し、カス
プ磁場１６の強度が一定となるように制御する。即ち、
石英るつぼ１３の内径をＤとするとき、カスプ磁場１６
の中立面１６ａをシリコン融液１４の表面から０．２０
Ｄ〜Ｄ、好ましくは０．２０Ｄ〜０．６６Ｄ下がった位
置になるように制御し、カスプ磁場１６の中立面１６ａ
上であって石英るつぼ１３の回転軸との交点から半径方
向に３００ｍｍ離れた円周上でのカスプ磁場１６の水平
方向の強度が５０〜３００ガウス、好ましくは１５０〜
２５０ガウスの範囲内の一定値となるように制御する。Returning to FIG. 1, the neutral plane 1 of the cusp magnetic field 16 is shown.
The distance between 6a and the surface of the silicon melt 14 is set to the quartz crucible 1
The cusp magnetic field 16 is controlled so that its intensity is constant with respect to the inner diameter of 3. That is,
When the inner diameter of the quartz crucible 13 is D, the cusp magnetic field 16
From the surface of the silicon melt 14 to the neutral surface 16a of 0.20
The neutral plane 16a of the cusp magnetic field 16 is controlled so as to be at a position lowered by D to D, preferably 0.20D to 0.66D.
The horizontal strength of the cusp magnetic field 16 on the circumference 300 mm in the radial direction from the intersection with the axis of rotation of the quartz crucible 13 is 50 to 300 gauss, preferably 150 to
It is controlled so as to be a constant value within the range of 250 gauss.
【００１９】なお、カスプ磁場１６の中立面１６ａの位
置を０．２０Ｄ〜Ｄの範囲に限定したのは、０．２０Ｄ
未満或いはＤを越えると、石英るつぼ１３の底部付近の
磁場強度が強くなり、この底部から固液界面１９方向へ
の対流が減少し、インゴット１７直下の温度が低下し、
固液界面１９の下方に突出する割合が大きくなる、即ち
固液界面１９における鉛直方向の温度勾配の面内均一性
が悪化し、パーフェクト領域となるインゴット１７の引
上げ速度の許容範囲が狭くなるからである。またカスプ
磁場１６の中立面１６ａ上であって石英るつぼ１３の回
転軸との交点から半径方向に３００ｍｍ離れた円周上で
のカスプ磁場１６の水平方向の強度を５０〜３００ガウ
スの範囲に限定したのは、５０ガウス未満では、無磁場
と同等であり、インゴットの引上げ速度を厳密に制御し
なくても、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という本発明の目的を達成
できず、３００ガウスを越えると、石英るつぼ１３の底
部付近の磁場強度が強くなり、この底部から固液界面１
９方向への対流が減少し、インゴット１７直下の温度が
低下し、固液界面１９の下方に突出する割合が大きくな
る、即ち固液界面１９における鉛直方向の温度勾配の面
内均一性が悪化し、パーフェクト領域となるインゴット
１７の引上げ速度の許容範囲が狭くなるからである。Note that the position of the neutral surface 16a of the cusp magnetic field 16 is limited to the range of 0.20D to D by 0.20D.
When it is less than or exceeds D, the magnetic field strength near the bottom of the quartz crucible 13 becomes strong, the convection from this bottom toward the solid-liquid interface 19 decreases, and the temperature immediately below the ingot 17 decreases,
The rate of protrusion below the solid-liquid interface 19 becomes large, that is, the in-plane uniformity of the vertical temperature gradient at the solid-liquid interface 19 deteriorates, and the allowable range of the pulling speed of the ingot 17 that is a perfect region becomes narrow. Is. The horizontal strength of the cusp magnetic field 16 on the neutral surface 16a of the cusp magnetic field 16 on the circumference 300 mm in the radial direction from the intersection with the axis of rotation of the quartz crucible 13 is set in the range of 50 to 300 Gauss. What is limited is that less than 50 Gauss is equivalent to no magnetic field, and it is relatively easy to produce a defect-free high-quality silicon single crystal ingot without strictly controlling the pulling speed of the ingot. If the object of the invention cannot be achieved and the value exceeds 300 Gauss, the magnetic field strength in the vicinity of the bottom of the quartz crucible 13 becomes strong.
The convection in the nine directions is reduced, the temperature immediately below the ingot 17 is decreased, and the ratio of protrusion below the solid-liquid interface 19 is increased, that is, the in-plane uniformity of the vertical temperature gradient at the solid-liquid interface 19 is deteriorated. However, the allowable range of the pulling speed of the ingot 17, which is the perfect region, is narrowed.
【００２０】具体的には、上記インゴット１７の直径が
２００ｍｍであって、石英るつぼ１３の内径Ｄが６００
ｍｍであるときには、カスプ磁場１６の中立面１６ａを
シリコン融液１４の表面から１２０〜６００ｍｍ、好ま
しくは１２０〜４００ｍｍ下がった位置になるように制
御し、カスプ磁場１６の中立面１６ａ上であって石英る
つぼ１３の回転軸との交点から半径方向に３００ｍｍ離
れた円周上でのカスプ磁場１６の水平方向の強度が５０
〜３００ガウス、好ましくは１５０〜２５０ガウスの範
囲内の一定値となるように制御する。また上記インゴッ
ト１７の直径が３００ｍｍであって、石英るつぼ１３の
内径Ｄが８００ｍｍであるときには、カスプ磁場１６の
中立面１６ａをシリコン融液１４の表面から１６０〜８
００ｍｍ、好ましくは１６０〜５３３ｍｍ下がった位置
になるように制御し、カスプ磁場１６の中立面１６ａ上
であって石英るつぼ１３の回転軸との交点から半径方向
に３００ｍｍ離れた円周上でのカスプ磁場１６の水平方
向の強度が５０〜３００ガウス、好ましくは１５０〜２
５０ガウスの範囲内の一定値となるように制御する。Specifically, the ingot 17 has a diameter of 200 mm and the quartz crucible 13 has an inner diameter D of 600.
When it is mm, the neutral surface 16a of the cusp magnetic field 16 is controlled so as to be at a position lower than the surface of the silicon melt 14 by 120 to 600 mm, preferably 120 to 400 mm. Therefore, the horizontal strength of the cusp magnetic field 16 on the circumference 300 mm away from the intersection with the rotation axis of the quartz crucible 13 in the radial direction is 50.
The value is controlled to be a constant value within the range of 300 gausses, preferably 150 to 250 gausses. When the diameter of the ingot 17 is 300 mm and the inner diameter D of the quartz crucible 13 is 800 mm, the neutral surface 16 a of the cusp magnetic field 16 is 160 to 8 from the surface of the silicon melt 14.
The position is controlled to be lowered by 00 mm, preferably 160 to 533 mm, and on the neutral surface 16a of the cusp magnetic field 16 on the circumference 300 mm away from the intersection point with the rotation axis of the quartz crucible 13 in the radial direction. The horizontal strength of the cusp magnetic field 16 is 50 to 300 Gauss, preferably 150 to 2
It is controlled so as to be a constant value within the range of 50 Gauss.
【００２１】なお、カスプ磁場１６の中立面１６ａの位
置と、カスプ磁場１６の中立面１６ａ上であって石英る
つぼ１３の回転軸との交点から半径方向に３００ｍｍ離
れた円周上でのカスプ磁場１６の水平方向の強度の制御
は、インゴット１７の直胴部１７ａ全長の引上げ時にわ
たって、或いはインゴット１７のトップ部１７ｂ、直胴
部１７ａ及びボトム部１７ｃの全長の引上げ時にわたっ
て、即ちインゴット１７の固化率が０〜１００％の範囲
内で行ってもよい。しかし、図３に示すように、インゴ
ット１７の固化率が５０〜１００％の範囲内、即ちイン
ゴット１７の直胴部１７ａの後半部分１７ｄ及びボトム
部１７ｂの引上げ時、或いはインゴット１７の直胴部１
７ａの後半部分１７ｄの引上げ時に行ってもよい。ここ
でインゴット１７の固化率とは、インゴット１７を引上
げる前のシリコン融液１４の重量に対する、シリコン融
液１４から引上げられるインゴット１７の重量の割合を
いう。また上記制御を行うインゴット１７の固化率の範
囲を５０〜１００％に限定したのは、５０％未満では、
カーボンパーツ等により固液界面１９における鉛直方向
の温度勾配の面内均一性を高めた初期引上げ状態を維持
することができ、特にカスプ磁場を印加する必要性が乏
しいからである。The position of the neutral surface 16a of the cusp magnetic field 16 and the neutral surface 16a of the cusp magnetic field 16 on the circumference of 300 mm in the radial direction from the intersection with the rotation axis of the quartz crucible 13. The horizontal strength of the cusp magnetic field 16 is controlled during pulling up of the entire length of the straight body portion 17a of the ingot 17, or during pulling up of the full length of the top portion 17b, the straight body portion 17a and the bottom portion 17c of the ingot 17, that is, the ingot. The solidification rate of 17 may be within the range of 0 to 100%. However, as shown in FIG. 3, the solidification rate of the ingot 17 is in the range of 50 to 100%, that is, when the rear half portion 17d and the bottom portion 17b of the straight body portion 17a of the ingot 17 are pulled up, or the straight body portion of the ingot 17 is pulled up. 1
It may be performed at the time of pulling up the latter half portion 17d of 7a. Here, the solidification rate of the ingot 17 refers to the ratio of the weight of the ingot 17 pulled up from the silicon melt 14 to the weight of the silicon melt 14 before pulling up the ingot 17. Further, the reason why the range of the solidification rate of the ingot 17 that performs the above control is limited to 50 to 100% is
This is because it is possible to maintain the initial pulling state in which the in-plane uniformity of the temperature gradient in the vertical direction at the solid-liquid interface 19 is improved by the carbon parts or the like, and it is particularly unnecessary to apply the cusp magnetic field.
【００２２】上述のようにカスプ磁場１６の中立面１６
ａの位置及びカスプ磁場１６の鉛直方向の強度を制御し
ながら、シリコン単結晶のインゴット１７を引上げる
と、石英るつぼ１３の底部近傍を循環する比較的流速の
速い第１対流１４ａが発生するとともに、固液界面１９
近傍と石英るつぼ１３周縁近傍とを循環する第２対流１
４ｂが発生する。上記第１対流１４ａはインゴット１７
の下方に固液界面１９から比較的離れているので、イン
ゴット１７中心直下の熱は比較的高く保持される、即ち
固液界面１９の下方に突出する割合が小さくなって固液
界面１９は平面に近い形状となる。As described above, the neutral plane 16 of the cusp magnetic field 16
When the silicon single crystal ingot 17 is pulled up while controlling the position of a and the strength of the cusp magnetic field 16 in the vertical direction, a first convection flow 14a that circulates near the bottom of the quartz crucible 13 and has a relatively high flow rate is generated. , Solid-liquid interface 19
Second convection 1 circulating in the vicinity and in the vicinity of the periphery of the quartz crucible 13
4b occurs. The first convection 14a is an ingot 17
Is relatively distant from the solid-liquid interface 19 below, the heat immediately below the center of the ingot 17 is kept relatively high, that is, the proportion of protrusion below the solid-liquid interface 19 is small, and the solid-liquid interface 19 is flat. The shape is close to.
【００２３】一方、インゴット１７内がパーフェクト領
域［Ｐ］となるためのインゴット１７の引上げ速度の許
容範囲は、第１及び第２対流１４ａ，１４ｂの変化によ
り固液界面１６ａの面内での鉛直方向の温度勾配が均一
になる、即ちパーフェクト領域となる引上げ速度の面内
均一性が向上するという理由により広くなるので、イン
ゴット１７の引上げ速度の制御は比較的容易になる。更
に上記第１及び第２対流１４ａ，１４ｂはインゴット１
７の引上げ工程のほぼ全工程にわたって発生し続けるた
め、インゴット１７のボトム１７ｂ側の引上げ時であっ
ても、固液界面１９の下方に突出する割合が小さく固液
界面１９が平面に近い形状に保たれる。即ち、インゴッ
ト１７内がパーフェクト領域［Ｐ］となるためのインゴ
ット１７の引上げ速度の許容範囲は殆ど減少しない。こ
の結果、インゴット１７の引上げ速度を厳密に制御しな
くても、インゴット１７の直胴部１７ａの全長にわたっ
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。On the other hand, the allowable range of the pulling speed of the ingot 17 so that the inside of the ingot 17 becomes the perfect region [P] is the vertical range within the plane of the solid-liquid interface 16a due to the change of the first and second convections 14a and 14b. Since the temperature gradient in the direction becomes wide, that is, the in-plane uniformity of the pulling speed that is a perfect region is improved, the pulling speed of the ingot 17 can be controlled relatively easily. Further, the first and second convections 14a and 14b are the ingot 1
Since almost all of the pulling process of No. 7 continues to occur, even when the bottom 17b of the ingot 17 is pulled up, the proportion of protrusion below the solid-liquid interface 19 is small and the solid-liquid interface 19 has a shape close to a plane. To be kept. That is, the allowable range of the pulling speed of the ingot 17 for making the inside of the ingot 17 the perfect region [P] hardly decreases. As a result, a defect-free, high-quality silicon single crystal ingot can be relatively easily manufactured over the entire length of the straight body portion 17a of the ingot 17 without strictly controlling the pulling speed of the ingot 17.
【００２４】[0024]
【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に示すように、内径が６００ｍｍの石
英るつぼ１３にシリコン融液１４を貯留し、この石英る
つぼ１３の外周面をヒータ１８により包囲した。またコ
イル直径が１４５０ｍｍである第１及び第２コイル１
１，１２を、石英るつぼ１３の回転軸をコイル中心とし
かつ鉛直方向に４１０ｍｍあけて配設した。更にこれら
のコイル１１，１２の互いに逆向きの電流を流すことに
より、各コイル中心から第１及び第２コイルの中立面を
通るカスプ磁場１６を発生させた。このカスプ磁場の中
立面１６ａが固液界面１９から下方に３００ｍｍとなる
ように第１及び第２コイル１１，１２の位置を制御し、
シリコン融液１４の表面におけるカスプ磁場１６の鉛直
方向の強度が２００ガウスとなるように各コイルに流す
電流を制御した。この状態で直径２００ｍｍのシリコン
単結晶のインゴット１７を上記シリコン融液１４から引
上げた。このときの引上げ速度は、図６（ｄ）に示すよ
うに、引上げ長が０ｍｍから７００ｍｍまでは０．７ｍ
ｍ／分から０．３ｍｍ／分まで次第に低下させ、引上げ
長が７００ｍｍから１４００ｍｍまでは０．３ｍｍ／分
から０．７ｍｍ／分まで次第に増大させた。このように
製造されたシリコン単結晶のインゴット１７を実施例１
とした。EXAMPLES Next, examples of the present invention will be described in detail together with comparative examples. <Example 1> As shown in FIG. 1, a silicon melt 14 was stored in a quartz crucible 13 having an inner diameter of 600 mm, and the outer peripheral surface of the quartz crucible 13 was surrounded by a heater 18. Also, the first and second coils 1 having a coil diameter of 1450 mm
Nos. 1 and 12 were arranged with the axis of rotation of the quartz crucible 13 as the center of the coil and opened 410 mm in the vertical direction. Further, by supplying currents in the coils 11 and 12 in directions opposite to each other, a cusp magnetic field 16 passing from the center of each coil to the neutral planes of the first and second coils was generated. The positions of the first and second coils 11 and 12 are controlled so that the neutral surface 16a of the cusp magnetic field is 300 mm below the solid-liquid interface 19.
The current passed through each coil was controlled so that the vertical strength of the cusp magnetic field 16 on the surface of the silicon melt 14 was 200 gauss. In this state, a silicon single crystal ingot 17 having a diameter of 200 mm was pulled up from the silicon melt 14. The pulling speed at this time is 0.7 m when the pulling length is from 0 mm to 700 mm, as shown in FIG.
It was gradually decreased from m / min to 0.3 mm / min, and was gradually increased from 0.3 mm / min to 0.7 mm / min when the pulling length was 700 mm to 1400 mm. The silicon single crystal ingot 17 manufactured in this manner was used in Example 1.
And
【００２５】＜比較例１＞図２に示すように、カスプ磁
場６の中立面６ａが固液界面９と略同一となるように第
１及び第２コイル１，２の位置を制御し、シリコン融液
４の表面におけるカスプ磁場６の鉛直方向の強度が６０
０ガウスとなるように各コイルに流す電流を制御したこ
とを除いて、実施例１と同様にしてシリコン単結晶のイ
ンゴット７ａを引上げた。このインゴット７ａを比較例
１とした。なお、図４の符号３は実施例１と同一の石英
るつぼであり、符号８は実施例１と同一のヒータであ
る。＜比較例２＞図３に示すように、カスプ磁場を発生
させないことを除いて、実施例１と同様にしてシリコン
単結晶のインゴット７ｂを引上げた。このインゴット７
ｂを比較例２とした。なお、図３において図２と同一符
号は同一部品を示す。<Comparative Example 1> As shown in FIG. 2, the positions of the first and second coils 1 and 2 are controlled so that the neutral surface 6a of the cusp magnetic field 6 is substantially the same as the solid-liquid interface 9. The vertical strength of the cusp magnetic field 6 on the surface of the silicon melt 4 is 60.
A silicon single crystal ingot 7a was pulled up in the same manner as in Example 1 except that the current passed through each coil was controlled so as to be 0 Gauss. This ingot 7a was used as Comparative Example 1. Note that reference numeral 3 in FIG. 4 is the same quartz crucible as that of the first embodiment, and reference numeral 8 is the same heater as that of the first embodiment. Comparative Example 2 As shown in FIG. 3, the silicon single crystal ingot 7b was pulled up in the same manner as in Example 1 except that the cusp magnetic field was not generated. This ingot 7
b was used as Comparative Example 2. 3 that are the same as those in FIG. 2 indicate the same parts.
【００２６】＜比較試験１及び評価＞実施例１、比較例
１及び比較例２のインゴットを軸方向にスライスして、
各インゴットの内部の欠陥の分布状態を調べた。その結
果を図６（ａ）〜図６（ｃ）に示す。図６（ａ）〜図６
（ｃ）から明らかなように、インゴットの引上げ速度を
次第に低下させた場合、比較例１では、全体にわたって
パーフェクト領域［Ｐ］となるシリコンウェーハは製造
できなかったのに対し、比較例２及び実施例１では、全
体にわたってパーフェクト領域［Ｐ］となるシリコンウ
ェーハを、引上げ方向に長さＭ1及びＬ1の範囲でそれぞ
れ切出すことができた。なお、長さＭ1及びＬ1は略同一
であった。一方、インゴットの引上げ速度を次第に増大
させた場合、比較例１では、パーフェクト領域［Ｐ］が
全く出現しなかったのに対し、比較例２及び実施例１で
は、全体にわたってパーフェクト領域［Ｐ］となるシリ
コンウェーハを、引上げ方向に長さＭ2及びＬ2の範囲で
それぞれ切出すことができた。但し、Ｌ2＞Ｍ2であるた
め、図６（ｄ）から明らかなように、インゴット内部が
パーフェクト領域［Ｐ］となる引上げ速度の許容範囲は
実施例１の方が比較例２より広かった、即ちＬ3＞Ｍ3で
あった。<Comparative Test 1 and Evaluation> The ingots of Example 1, Comparative Example 1 and Comparative Example 2 were sliced in the axial direction,
The distribution of defects inside each ingot was examined. The results are shown in FIGS. 6 (a) to 6 (c). 6 (a) to 6
As is clear from (c), in the case where the pulling speed of the ingot was gradually decreased, in Comparative Example 1, it was not possible to manufacture a silicon wafer having the perfect region [P] over the entire area. In Example 1, it was possible to cut out a silicon wafer that would be the perfect region [P] over the entire length in the pulling direction within the lengths M 1 and L 1 . The lengths M 1 and L 1 were substantially the same. On the other hand, when the pulling speed of the ingot was gradually increased, in Comparative Example 1, the perfect region [P] did not appear at all, whereas in Comparative Example 2 and Example 1, the perfect region [P] was entirely formed. The resulting silicon wafer could be cut out in the pulling direction within the ranges of lengths M 2 and L 2 . However, since L 2 > M 2 , as is apparent from FIG. 6D, the allowable range of the pulling speed at which the inside of the ingot is the perfect region [P] was wider in Example 1 than in Comparative Example 2. That is, L 3 > M 3 .
【００２７】＜比較試験２及び評価＞実施例１及び比較
例２のインゴット引上げ時の固化率を増大させたとき
の、無欠陥領域となるインゴットの引上げ速度の許容範
囲を図７に示す。図７から明らかなように、比較例２で
は、固化率が５０％を越えると、パーフェクト領域
［Ｐ］となるインゴットの引上げ速度の許容範囲が急激
に減少したのに対し、実施例１では、固化率が５０％を
越えても、パーフェクト領域［Ｐ］となるインゴットの
引上げ速度の許容範囲は殆ど減少しなかった。<Comparative Test 2 and Evaluation> FIG. 7 shows the permissible range of the pulling speed of the ingot which is a defect-free region when the solidification rate at the time of pulling the ingot of Example 1 and Comparative Example 2 is increased. As is clear from FIG. 7, in Comparative Example 2, when the solidification rate exceeded 50%, the allowable range of the pulling speed of the ingot that was in the perfect region [P] was sharply decreased, whereas in Example 1, Even when the solidification rate exceeds 50%, the allowable range of the pulling speed of the ingot which is in the perfect region [P] is hardly reduced.
【００２８】[0028]
【発明の効果】以上述べたように、本発明によれば、石
英るつぼの内径をＤとするとき、カスプ磁場の中立面を
シリコン融液の表面から０．２０Ｄ〜Ｄ下がった位置に
なるように制御し、カスプ磁場の中立面上であって石英
るつぼの回転軸との交点から半径方向に３００ｍｍ離れ
た円周上でのカスプ磁場の水平方向の強度が５０〜３０
０ガウスの範囲内の一定値となるように制御したので、
インゴット中心直下の熱は比較的高く保持されて、固液
界面が下方に突出する割合が小さくなる。即ち、固液界
面における鉛直方向の温度勾配の面内均一性が高くな
り、インゴットの引上げ速度及び上記温度勾配の比（Ｖ
／Ｇ）の面内均一性が向上する。この結果、インゴット
の径方向でパーフェクト領域となる引上げ速度が均一に
なり、インゴット内がパーフェクト領域となる引上げ速
度の許容範囲は広くなる。従って、インゴットの引上げ
速度を厳密に制御しなくても、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。As described above, according to the present invention, when the inner diameter of the quartz crucible is D, the neutral plane of the cusp magnetic field is located at a position lower by 0.20 D to D from the surface of the silicon melt. The horizontal strength of the cusp magnetic field is 50 to 30 on the neutral plane of the cusp magnetic field, which is 300 mm in the radial direction from the intersection with the axis of rotation of the quartz crucible.
Since it was controlled to be a constant value within the range of 0 Gauss,
The heat just below the center of the ingot is kept relatively high, and the proportion of the solid-liquid interface protruding downward becomes small. That is, the in-plane uniformity of the vertical temperature gradient at the solid-liquid interface becomes high, and the ingot pulling speed and the ratio of the temperature gradient (V
/ G) improves the in-plane uniformity. As a result, the pulling speed in the perfect region becomes uniform in the radial direction of the ingot, and the allowable range of the pulling speed in which the inside of the ingot becomes the perfect region becomes wide. Therefore, a defect-free, high-quality silicon single crystal ingot can be relatively easily manufactured without strictly controlling the pulling speed of the ingot.
【００２９】また上記インゴットの固化率が５０〜１０
０％の範囲内であるときに、カスプ磁場の中立面の位置
と、カスプ磁場の中立面上であって石英るつぼの回転軸
との交点から半径方向に３００ｍｍ離れた円周上でのカ
スプ磁場の水平方向の強度を所定の範囲でそれぞれ制御
すれば、インゴットのボトム側の引上げ時であっても、
固液界面の下方に突出する割合が小さくなり、固液界面
が平面に近い形状に保たれる。この結果、インゴット内
がパーフェクト領域となるためのインゴットの引上げ速
度の許容範囲は殆ど減少しないので、インゴットの直胴
部の全長にわたって無欠陥で高品質のシリコン単結晶の
インゴットを製造できる。The solidification rate of the ingot is 50 to 10
When in the range of 0%, the position of the neutral plane of the cusp magnetic field and the neutral plane of the cusp magnetic field on the circumference of 300 mm in the radial direction from the intersection point with the axis of rotation of the quartz crucible. If the horizontal strength of the cusp magnetic field is controlled within a predetermined range, even when pulling the bottom side of the ingot,
The proportion of protrusion below the solid-liquid interface is reduced, and the solid-liquid interface is maintained in a shape close to a plane. As a result, the allowable range of the pulling speed of the ingot for making the inside of the ingot a perfect region is hardly reduced, so that it is possible to manufacture a defect-free and high-quality silicon single crystal ingot over the entire length of the straight body portion of the ingot.
【図１】本発明実施形態及び実施例１のシリコン単結晶
を引上げている状態を示す断面構成図。FIG. 1 is a cross-sectional configuration diagram showing a state where a silicon single crystal according to an embodiment of the present invention and a silicon single crystal of Example 1 is pulled up.
【図２】ボロンコフの理論を基づいた、Ｖ／Ｇ比が臨界
点以上では空孔型点欠陥濃度が優勢なインゴットが形成
され、Ｖ／Ｇ比が臨界点以下では格子間シリコン型点欠
陥濃度が優勢なインゴットが形成されることを示す図。FIG. 2 is an ingot in which the vacancy type point defect concentration is dominant when the V / G ratio is above the critical point, and the interstitial silicon type point defect concentration is when the V / G ratio is below the critical point, based on the Boronkov theory. The figure which shows that a predominant ingot is formed.
【図３】引上げられたシリコン単結晶のインゴットの側
面図。FIG. 3 is a side view of a pulled silicon single crystal ingot.
【図４】比較例１を示す図１に対応する断面構成図。FIG. 4 is a sectional configuration diagram corresponding to FIG. 1 showing Comparative Example 1.
【図５】比較例２を示す図１に対応する断面構成図。5 is a sectional configuration diagram corresponding to FIG. 1 showing a comparative example 2. FIG.
【図６】（ａ）〜（ｃ） 比較例１、比較例２及び実施
例１のシリコン単結晶のインゴットの引上げ速度を変化
させたときの、各インゴット内の欠陥分布の変化を示す
図。
（ｄ） 比較例１、比較例２及び実施例１のインゴット
の引上げ長の変化に対するインゴットの引上げ速度の変
化を示す図。6A to 6C are diagrams showing changes in defect distribution in each ingot when the pulling rate of the silicon single crystal ingots of Comparative Example 1, Comparative Example 2 and Example 1 was changed. (D) The figure which shows the change of the pulling-up speed of the ingot with respect to the change of the pulling-up length of the ingot of Comparative Example 1, Comparative Example 2, and Example 1.
【図７】実施例１及び比較例２のシリコン単結晶のイン
ゴットを引上げてその固化率を変化させたときの、パー
フェクト領域となるインゴットの引上げ速度の許容範囲
の変化を示す図。FIG. 7 is a diagram showing a change in an allowable range of a pulling rate of an ingot which is a perfect region when the silicon single crystal ingots of Example 1 and Comparative Example 2 are pulled and the solidification rate thereof is changed.
１１ 第１コイル １２ 第２コイル １３ 石英るつぼ １４ シリコン融液 １４ａ 第１対流 １４ｂ 第２対流 １６ カスプ磁場 １６ａ カスプ磁場の中立面 １７ シリコン単結晶のインゴット １７ａ 直胴部 １７ｂ ボトム １９ 固液界面 11 first coil 12 Second coil 13 Quartz crucible 14 Silicon melt 14a First convection 14b Second convection 16 Cusp magnetic field 16a Neutral plane of cusp magnetic field 17 Silicon single crystal ingot 17a Straight body part 17b bottom 19 Solid-liquid interface
───────────────────────────────────────────────────── フロントページの続き (72)発明者 符 森林 東京都千代田区大手町１丁目５番１号 三 菱マテリアルシリコン株式会社内 Ｆターム(参考） 4G077 AA02 BA04 CF10 EJ02 HA12 PF55 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Mark Forest 3-5-1 Otemachi, Chiyoda-ku, Tokyo Ryo Material Silicon Co., Ltd. F-term (reference) 4G077 AA02 BA04 CF10 EJ02 HA12 PF55
Claims (4)
げるためのシリコン融液(14)を石英るつぼ(13)に貯留
し、この石英るつぼの外径より大きなコイル直径を有す
る第１及び第２コイル(11,12)を前記石英るつぼの回転
軸をそれぞれコイル中心としかつ鉛直方向に所定の間隔
をあけて配設し、前記第１及び第２コイルに互いに逆向
きの電流を流すことにより前記第１及び第２コイルの各
コイル中心から前記第１及び第２コイル間の水平面であ
る中立面(16a)を通るカスプ磁場(16)が発生し、前記カ
スプ磁場の中立面と前記シリコン融液(14)の表面との距
離を前記石英るつぼ(13)の内径に対して所定の割合とな
るように制御し、前記カスプ磁場(16)の強度が一定とな
るように制御し、前記インゴット(17)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
トを引上げるシリコン単結晶の製造方法において、 前記石英るつぼ(13)の内径をＤとするとき、前記カスプ
磁場(16)の中立面(16a)を前記シリコン融液(14)の表面
から０．２０Ｄ〜Ｄ下がった位置になるように制御し、 前記カスプ磁場(16)の中立面(16a)上であって前記石英
るつぼ(13)の回転軸との交点から半径方向に３００ｍｍ
離れた円周上での前記カスプ磁場(16)の水平方向の強度
が５０〜３００ガウスの範囲内の一定値となるように制
御することを特徴とするシリコン単結晶の製造方法。1. A silicon melt (14) for pulling up a silicon single crystal ingot (17) is stored in a quartz crucible (13), and a first and a first coil having a coil diameter larger than the outer diameter of the quartz crucible. By arranging two coils (11, 12) with the rotation axes of the quartz crucible as the center of the coils and at a predetermined interval in the vertical direction, and applying currents in opposite directions to the first and second coils. A cusp magnetic field (16) is generated from each coil center of the first and second coils and passes through a neutral plane (16a) which is a horizontal plane between the first and second coils, and the cusp magnetic field and the neutral plane are The distance from the surface of the silicon melt (14) is controlled to be a predetermined ratio with respect to the inner diameter of the quartz crucible (13), and the cusp magnetic field (16) is controlled to have a constant strength, The inside of the ingot (17) contains agglomerates of interstitial silicon type point defects and vacancy type point defects. In the method for manufacturing a silicon single crystal in which the ingot is pulled at a pulling rate that is a perfect region where no aggregate exists, in the case where the inner diameter of the quartz crucible (13) is D, the neutral surface (16a of the cusp magnetic field (16a) ) Is controlled so as to be at a position lower than the surface of the silicon melt (14) by 0.20 D to D, on the neutral surface (16a) of the cusp magnetic field (16) and in the quartz crucible (13). 300mm in the radial direction from the intersection with the rotation axis of
A method for producing a silicon single crystal, characterized in that the intensity of the cusp magnetic field (16) in a horizontal direction on a distant circumference is controlled to be a constant value within a range of 50 to 300 Gauss.
って、石英るつぼ(13)の内径Ｄが６００ｍｍであるとき
に、カスプ磁場(16)の中立面(16a)をシリコン融液(14)
の表面から１２０〜６００ｍｍ下がった位置になるよう
に制御し、前記カスプ磁場(16)の中立面(16a)上であっ
て前記石英るつぼ(13)の回転軸との交点から半径方向に
３００ｍｍ離れた円周上での前記カスプ磁場(16)の水平
方向の強度が５０〜３００ガウスの範囲内の一定値とな
るように制御する請求項１記載のシリコン単結晶の製造
方法。2. When the ingot (17) has a diameter of 200 mm and the quartz crucible (13) has an inner diameter D of 600 mm, the neutral surface (16a) of the cusp magnetic field (16) is fixed to the silicon melt (14). )
It is controlled so as to be 120 to 600 mm lower than the surface of the quartz crucible (13) on the neutral plane (16a) of the cusp magnetic field (16) in the radial direction from the intersection with the rotation axis of the quartz crucible (13). 2. The method for producing a silicon single crystal according to claim 1, wherein the intensity of the cusp magnetic field (16) in the horizontal direction on the circumferentially spaced apart is controlled to be a constant value within the range of 50 to 300 Gauss.
って、石英るつぼ(13)の内径Ｄが８００ｍｍであるとき
に、カスプ磁場(16)の中立面(16a)をシリコン融液(14)
の表面から１６０〜８００ｍｍ下がった位置になるよう
に制御し、前記カスプ磁場(16)の中立面(16a)上であっ
て前記石英るつぼ(13)の回転軸との交点から半径方向に
３００ｍｍ離れた円周上での前記カスプ磁場(16)の水平
方向の強度が５０〜３００ガウスの範囲内の一定値とな
るように制御する請求項１記載のシリコン単結晶の製造
方法。3. When the diameter of the ingot (17) is 300 mm and the inner diameter D of the quartz crucible (13) is 800 mm, the neutral surface (16a) of the cusp magnetic field (16) is fixed to the silicon melt (14). )
It is controlled to be a position lower by 160 to 800 mm from the surface of the quartz crucible (16) on the neutral surface (16a) of the cusp magnetic field (16) in the radial direction from the intersection with the rotation axis of the quartz crucible (13). 2. The method for producing a silicon single crystal according to claim 1, wherein the intensity of the cusp magnetic field (16) in the horizontal direction on the circumferentially spaced apart is controlled to be a constant value within the range of 50 to 300 Gauss.
融液(14)の重量に対する、シリコン融液(14)から引上げ
られるインゴット(17)の重量の割合である固化率が５０
〜１００％の範囲内であるときに、カスプ磁場(16)の中
立面(16a)の位置と、前記カスプ磁場(16)の中立面(16a)
上であって前記石英るつぼ(13)の回転軸との交点から半
径方向に３００ｍｍ離れた円周上での前記カスプ磁場(1
6)の水平方向の強度とを請求項１ないし３いずれか記載
の範囲でそれぞれ制御するシリコン単結晶の製造方法。4. The solidification rate, which is the ratio of the weight of the ingot (17) pulled up from the silicon melt (14) to the weight of the silicon melt (14) before pulling up the ingot (17), is 50.
The position of the neutral plane (16a) of the cusp magnetic field (16) and the neutral plane (16a) of the cusp magnetic field (16) when within the range of 100%
The cusp magnetic field (1) on the circumference which is 300 mm in the radial direction from the intersection point with the rotation axis of the quartz crucible (13).
A method for producing a silicon single crystal, wherein the horizontal strength in 6) is controlled within the range according to any one of claims 1 to 3.
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| JP2001181583A JP2003002783A (en) | 2001-06-15 | 2001-06-15 | Method for producing silicon single crystal |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005073440A1 (en) * | 2004-01-30 | 2005-08-11 | Sumitomo Mitsubishi Silicon Corporation | Method of lifting silicon single crystal |
| US7300518B2 (en) | 2004-05-19 | 2007-11-27 | Sumco Corporation | Apparatus and method for producing single crystal, and silicon single crystal |
| KR101540566B1 (en) * | 2013-10-11 | 2015-07-31 | 주식회사 엘지실트론 | A method of growing a single crystal ingot |
-
2001
- 2001-06-15 JP JP2001181583A patent/JP2003002783A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005073440A1 (en) * | 2004-01-30 | 2005-08-11 | Sumitomo Mitsubishi Silicon Corporation | Method of lifting silicon single crystal |
| US7282095B2 (en) | 2004-01-30 | 2007-10-16 | Sumco Corporation | Silicon single crystal pulling method |
| KR100806001B1 (en) * | 2004-01-30 | 2008-02-26 | 가부시키가이샤 섬코 | Method of lifting silicon single crystal |
| US7300518B2 (en) | 2004-05-19 | 2007-11-27 | Sumco Corporation | Apparatus and method for producing single crystal, and silicon single crystal |
| US7780783B2 (en) | 2004-05-19 | 2010-08-24 | Sumco Corporation | Apparatus and method for producing single crystal, and silicon single crystal |
| KR101540566B1 (en) * | 2013-10-11 | 2015-07-31 | 주식회사 엘지실트론 | A method of growing a single crystal ingot |
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