JP2004107166A - Single crystal pulling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a single crystal pulling device in which a positional adjustment between a seed crystal and an auxiliary heating means is easy; the time for adjustment operation can be reduced; the width of vibration can be controlled within a very small range even when the seed crystal vibrates like a rotary pendulum as the seed crystal rotates; heating efficiency by the auxiliary heating means is improved; the controllability of a temperature distribution occurring in the seed crystal can be improved; and the operation for withdrawing the auxiliary heating means is not complicated, which is performed after the completion of a non-dislocation step of the seed crystal and before enlarging the diameter of the seed crystal to form a main body. <P>SOLUTION: The apparatus for pulling a single crystal comprises a seed crystal-holding means for holding the seed crystal, an elevating means for elevating the seed crystal holding means, an auxiliary heating means 15 for partially heating the seed crystal 35 and the surface of a melt 23 along with a main heater 22, a moving means for moving the auxiliary heating means 15, and a power supply control means 13 for controlling power supply to the auxiliary heating means 15 and the main heater 22, wherein the apparatus is provided with a position control means 18 for controlling the position of the seed crystal 35 to the auxiliary heating means 15. <P>COPYRIGHT: (C)2004,JPO

Description

【００７５】
実施例１の場合、１０回の単結晶３６の引き上げのいずれも、無転位化のためのネック３６ａの形成において、画像処理手段１２がネック３６ａと溶融液２３との界面部分を見失うことがなく、直径の自動制御に失敗することがなかった。また、すべての単結晶３６の引き上げにおいて、無転位化に成功し、所定の長さのメインボディ部３６ｃを形成することができた。
【００７６】
一方、比較例１の場合、１０回の単結晶３６の引き上げのうち、７回の単結晶３６の引き上げにおいて、種結晶３５の振動により、直径計測が不可能となり、ネック３６ａ直径の自動制御ができなくなった。７回のうち５回はオペレーターが手動でネック３６ａ直径を制御することによりネック３６ａを形成することができたが、無転位化に成功したのは３回であり、残りの２回は有転位化し、単結晶３６の引き上げに失敗した。ネック３６ａ直径計測が不可能になった単結晶３６の引き上げのうち２回は、手動によるネック３６ａの制御に失敗し、溶融液２３から切り離された。ネック３６ａ直径計測が可能であった３回の単結晶３６の引き上げは無転位化に成功した。最終的に１０回の単結晶３６の引き上げのうち所定のメインボディ３６ｃを無転位で成長させることができたのは６回であった。
【００７７】
以上のように補助加熱装置１５ｃを使用する際に、実施の形態に係る位置制御手段１８を併用することにより、種結晶３５と保持具２４ａとの位置の整合作業の作業時間の短縮と、単結晶３６の引き上げ時における作業不可の低減と、単結晶３６の引き上げの成功率に大幅な向上が見られた。
＜実施例２に共通する条件＞
補助加熱装置１５にあらかじめ電力を供給し、種結晶３５を溶融液２３に接触させる前に十分加熱する。続いて溶融液２３に種結晶３５を接触させた後、ネック３６ａ（Ｌ＝１５０ｍｍ）を形成し、引き続いて単結晶３６を引き上げる。ネック３６ａを形成中、補助加熱手段１５により加熱を行う際に、位置制御手段１８によりネック３６ａの位置を制御した。この単結晶３６の引き上げを５回行った。
＜比較例２に共通する条件＞
補助加熱手段１５にあらかじめ電力を供給し、種結晶３５を溶融液２３に接触させる前に十分加熱する。続いて溶融液２３に種結晶３５を接触させた後、ネック３６ａ（Ｌ＝１５０ｍｍ）を形成し、引き続いて単結晶３６を引き上げる。ネック３６ａを形成中、補助加熱手段１５により加熱を行う際に、位置制御手段１８によるネック３６ａの位置制御を行わなかった。この単結晶３６の引き上げを５回行った。
【００７８】
実施例２と比較例２の結果を下記の表２に示す。
【表２】

【００７９】
実施例２の場合、５回の単結晶３６の引き上げのいずれも、無転位化のためのネック３６ａの形成において、画像処理手段１２がネック３６ａと溶融液２３の界面部分を見失うことなく、ネック３６ａ直径の自動制御に失敗することがなかった。すべての単結晶３６の引き上げにおいて、無転位化に成功し、所定の長さのメインボディ部３６ｃを形成することができた。
【００８０】
一方、比較例２の場合、５回の単結晶３６の引き上げのうち、３回の単結晶３６の引き上げにおいて、種結晶３５の振動により、ネック３６ａ直径計測が不可能となり、ネック３６ａ直径の自動制御ができなくなった。３回のうち２回はオペレーターが手動でネック３６ａ直径を制御することによりネック３６ａを形成できたが、無転位化に成功したのは１回であり、残りの１回は有転位化し単結晶３６の引き上げに失敗した。ネック３６ａ直径計測が不可能になった単結晶３６の引き上げのうち１回は、手動によるネック３６ａの制御に失敗し、溶融液２３から切り離された。ネック３６ａ直径計測が可能であった２回の単結晶３６の引き上げは無転位化に成功した。最終的に５回の単結晶３６の引き上げのうち所定のメインボディ３６ｃを無転位で成長させることができたのは３回であった。
【００８１】
以上のように補助加熱手段１５を使用する際に、実施の形態に係る位置制御手段１８を併用することにより、種結晶３５と保持具２４ａの位置の整合作業の作業時間の短縮と、単結晶３６の引き上げ時における作業不可の低減と、単結晶３６の引き上げの成功率に大幅な向上が見られた。
＜実施例３に共通する条件＞
補助加熱手段１５にあらかじめ電力を供給し、種結晶３５を溶融液２３に接触させる前に十分加熱する。つづいて溶融液２３に種結晶３５を浸漬させた後、直胴部３７（Ｌ２＝５０ｍｍ）を形成し、引き続いて単結晶３６を引き上げる。直胴部３７を引き上げ中、補助加熱手段１５により加熱を行う際に、位置制御手段１８により種結晶３５の位置を制御した。この単結晶３６の引き上げを５回行った。
＜比較例３に共通する条件＞
補助加熱手段１５にあらかじめ電力を供給し、種結晶３５を溶融液２３に接触させる前に十分加熱する。つづいて溶融液２３に種結晶３５を浸漬させた後、直胴部３７（Ｌ２＝５０ｍｍ）を形成し、引き続いて単結晶３６を引き上げる。直胴部３７を引き上げ中、補助加熱手段１５により加熱を行う際に、位置制御手段１８による種結晶３５の位置制御を行わなかった。この単結晶３６の引き上げを５回行った。
【００８２】
実施例３と比較例３の結果を下記の表３にまとめる。
【表３】

【００８３】
実施例３の場合には、５回の単結晶３６の引き上げのいずれも、無転位化のための直胴部３７の形成において、画像処理手段１２が直胴部３７と溶融液２３との界面部分を見失うことなく、直胴部３７直径の自動制御に失敗することがなかった。すべての単結晶３６の引き上げにおいて、無転位化に成功し、所定の長さのメインボディ部３６ｃを形成することができた。
【００８４】
比較例３では、５回の単結晶３６の引き上げのうち、２回の単結晶３６の引き上げにおいて、種結晶３５の振動により、直胴部３７直径計測が不可能となり、直胴部３７直径の自動制御ができなくなった。オペレーターが手動で直胴部３７直径を制御することにより１回は直胴部３７を形成できたが、無転位化はできなかった。残りの１回は直胴部３７直径制御に失敗し結晶が溶融液２３から切り離れた。直胴部３７直径計測が可能であった３回の単結晶３６の引き上げのうち２回は無転位化に失敗した。最終的に５回の単結晶３６の引き上げのうち所定のメインボディ３６ｃを無転位で成長させることができたのは１回であった。
【００８５】
以上のように補助加熱手段１５を使用する際に、実施の形態に係る位置制御手段１８を併用することにより、種結晶３５と保持具２４ａとの位置の整合作業の作業時間の短縮と、単結晶３６の引き上げにおける作業負荷の低減と、単結晶３６の引き上げの成功率に大幅な向上が見られた。
【００８６】
つぎに位置制御手段１８の形成に高融点金属を用い、絶縁スリーブ、絶縁ワッシャを介して、補助加熱手段１５の電極１５ｂに接合する位置制御手段１８を用いた例を紹介する。
＜実施例４に共通する条件＞
補助加熱手段１５にあらかじめ電力を供給し、種結晶３５を溶融液２３に接触させる前に十分予熱する。続いて溶融液２３に種結晶３５を接触させた後、ネック３６ａ（Ｌ＝１５０ｍｍ）を形成し、引き続いて単結晶３６を引き上げる。ネック３６ａを形成中、補助加熱手段１５により加熱を行う際に、位置制御手段１８によりネック３６ａの位置を制御した。この単結晶３６の引き上げを５回行った。
【００８７】
結果を下記の表４に示す。
【表４】

【００８８】
実施例４の場合、５回の単結晶３６の引き上げのいずれも、無転位化のためのネック３６ａの形成において、画像処理手段１２がネック３６ａと溶融液２３との界面部分を見失うことがなく、ネック３６ａ直径の自動制御に失敗することがなかった。すべての単結晶３６の引き上げにおいて、無転位化に成功し、所定の長さのメインボディ部３６ｃを形成することができた。また補助加熱手段１５に電気的な不具合を誘発することも無かった。
【００８９】
以上の実施例１、２、３、４と比較例１、２、３において、ネック３６ａ直径あるいは直胴部３７直径計測に成功し、単結晶３６の引き上げにも成功したものに１点、ネック３６ａ直径あるいは直胴部３７直径計測は失敗したが、単結晶３６の引き上げには成功したものに０．５点、単結晶３６の引き上げに失敗したものに０点をあたえ、実施例、比較例それぞれを合算したものをそれぞれ実験回数で割ったものを１００倍したものを下記の表５に示した。
【００９０】
【表５】

表５から本発明の効果は明らかであった。
【００９１】
なお、無転位のメインボディ３６ｃを有する単結晶３６の引き上げに成功した結晶については、結晶品質の測定を行った。その結果、実施例、比較例ともライフタイムなどの結晶の品質に差は無いことが明らかとなった。
【図面の簡単な説明】
【図１】本発明の実施の形態に係る単結晶引き上げ装置の要部を示す模式的部分断面図
【図２】（ａ）は実施の形態に係る単結晶引き上げ装置の要部を示す部分拡大平面図、（ｂ）は部分拡大側面図である。
【図３】実施の形態に係る単結晶引き上げ装置の要部を示す部分拡大側断面図である。
【図４】別の実施の形態に係る単結晶引き上げ装置の要部を示す部分拡大側断面図である。
【図５】別の実施の形態に係る単結晶引き上げ装置の要部を示す部分拡大平面図である。
【図６】（ａ）はさらに別の実施の形態に係る単結晶引き上げ装置の要部を示す部分拡大平面図、（ｂ）は部分拡大側面図である。
【図７】（ａ）〜（ｅ）は、実施の形態に係る単結晶引き上げ装置を用いた単結晶の引き上げ工程のうちの、一部の工程を実施する際の、種結晶近傍を模式的に示した部分断面拡大正面図である。
【図８】（ａ）〜（ｅ）は、実施の形態に係る単結晶引き上げ装置を用いた単結晶の引き上げ工程のうちの、一部の工程を実施する際の、種結晶近傍を模式的に示した部分断面拡大正面図である。
【図９】従来の単結晶引き上げ装置の要部を示す模式的部分断面図である。
【図１０】（ａ）〜（ｄ）は、従来の単結晶引き上げ装置を用いた単結晶の引き上げ工程のうちの、一部の工程を実施する際の、種結晶近傍を模式的に示した部分断面拡大正面図である。
【符合の説明】
１２　　　画像処理手段
１３　　　電力供給制御手段
１４　　　昇降速度制御手段
１５　　　補助加熱手段
１５ａ　　発熱部
１５ｂ　　電極
１６　　　種結晶径制御手段
１８　　　位置制御手段
１８ａ　　案内スロ−ト
１８ｂ　　移動量制限部
１８ｃ　　開口部
１８ｄ　　固定部
２１　　　坩堝
２２　　　メインヒ−タ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a single crystal pulling apparatus, and more particularly to a single crystal pulling apparatus used for pulling a single crystal made of silicon or the like by a pulling method represented by the Czochralski method (hereinafter, referred to as CZ method). About.
[0002]
[Prior art]
At present, most silicon single crystals used for manufacturing substrates for forming circuit elements such as large-scale integrated circuits (LSI) are pulled up by the CZ method. As a method of eliminating dislocations in a pulled single crystal, a method called a dash neck method is generally used, in which the diameter of the crystal is reduced to about several mm to eliminate dislocations. In recent years, with the increase in the diameter of the pulled single crystal, the weight of the single crystal has been increasing, and the load applied to the thin neck exceeds the tensile strength of silicon, and there is a high possibility that the crystal will fall during the pulling of the single crystal. It has become to.
[0003]
In order to cope with the above-mentioned fear, the seed crystal is preheated by using a movable auxiliary heating means, the dislocation caused by heat shock when the seed crystal is brought into contact with the melt is suppressed, and the single crystal is pulled up without forming a neck. The temperature distribution of the neck portion is controlled by heating the neck portion using an auxiliary heating means at the time of dislocation-free work by the dash neck method or the method of making the crystal dislocation-free (see Patent Document 1). A method has been developed in which the acting thermal stress can be reduced and a single crystal can be pulled out even in a neck portion having a diameter larger than usual without dislocation (see Patent Document 1).
[0004]
In addition, as a method of moving the auxiliary heating device, a slit-shaped opening is formed in an annular auxiliary heating heater surrounding the seed crystal, and after the dislocation-free work is completed, the crystal is passed through the opening, and The auxiliary heating heater is moved obliquely upward (for example, see Patent Document 2).
[0005]
FIG. 9 is a cross-sectional view schematically showing a conventional single crystal pulling apparatus equipped with an auxiliary heating means 15 for displacing a seed crystal by an auxiliary heating method used in the CZ method. The middle 21 indicates a crucible.
[0006]
The crucible 21 is composed of a quartz crucible 21a having a cylindrical shape with a bottom and a graphite crucible 21b also having a cylindrical shape with a bottom fitted to the outside of the quartz crucible 21a. Are supported by a support shaft 28 which rotates at a predetermined speed in the direction of arrow A in the figure. A main heater 22 of a resistance heating type is arranged outside the crucible 21, and a heat insulating cylinder 27 is arranged concentrically outside the main heater 22, and the inside of the crucible 21 is melted by the main heater 22. A melt 23 as a raw material for crystallization is filled. A pulling shaft 24 made of a pulling rod or a wire is suspended from the center axis of the crucible 21, and a seed crystal 35 is attached to the tip of the pulling shaft 24 via a holder 24a. Has become. These members are housed in a water-cooled chamber 29 capable of controlling the pressure. The auxiliary heating means 15 includes a heating part 15a and an electrode 15b, and is supported by the moving means 10 so as to be able to advance and retreat above the center of the quartz crucible 21a.
[0007]
A method for pulling the single crystal 36 using the above-described single crystal pulling apparatus will be described with reference to FIGS. FIGS. 10A to 10D are partially enlarged front views schematically showing the vicinity of a seed crystal in some of the steps for pulling a single crystal.
[0008]
Although not shown in FIG. 10, first, the inside of the chamber 29 is depressurized, and then an inert gas is introduced to make the inside of the chamber 29 a depressurized inert gas atmosphere. The gas in the molten liquid 23 is sufficiently released by leaving it to stand.
[0009]
Next, while rotating the pull-up shaft 24 at a predetermined speed in the opposite direction at the same axis as the support shaft 28, the seed crystal 35 attached to the holder 24a is lowered and immersed in the melt 23, After the tip of 35 has been adapted to the melt 23, pulling of the single crystal 36 is started (seeding step, FIG. 10A).
Next, a crystal is grown at the tip of the seed crystal 35. At this time, the interface between the seed crystal 35 and the melt 23 is heated by the heat-generating portion 15 a of the auxiliary heating means 15, resulting in the temperature distribution of the seed crystal 35. The thermal stress is reduced, and the neck 36a is formed to eliminate dislocations (dislocation-free step, FIG. 10B).
Next, the moving means 10 is driven to retract the heat generating portion 15a from the neck 36a, and then the pulling speed of the pulling shaft 24 (hereinafter, also simply referred to as pulling speed) is reduced to grow the neck 36a to a predetermined diameter. 36b is formed (shoulder forming step, FIG. 10C).
Next, the lifting shaft 24 is pulled up at a constant speed to form a main body 36c having a constant diameter and a predetermined length (main body forming step, FIG. 10D).
Thereafter, although not shown in FIG. 10, the diameter of the single crystal 36 is gradually reduced to gradually lower the temperature of the entire single crystal 36 so that high-density dislocations are not introduced into the single crystal 36 due to a sudden temperature change. To form a terminal cone. Thereafter, the single crystal 36 is separated from the melt 23 and cooled to complete the pulling of the single crystal 36.
[0010]
In the dislocation-free step shown in FIG. 10B, the diameter of the neck 36a is measured in order to automatically control the diameter of the neck 36a. As a general method of measuring the diameter of the neck 36a, when a crystal is brought into contact with a melt, a light ring called a fusion ring formed around the crystal is photographed with a measurement camera, and image analysis is performed to determine the diameter of the neck 36a. The calculation method is adopted.
[0011]
This fusion ring is formed by the following physical phenomena. When the crystal is brought into contact with the melt, the surface of the melt rises along the side wall of the crystal due to surface tension, and becomes curved into a concave surface when viewed from vertically above. The curved surface reflects the light of the surrounding incandescent quartz crucible, forming a bright ring. This bright ring is called a fusion ring.
[0012]
In the dislocation-free process using the auxiliary heating method, in order to heat the periphery of the contact portion between the seed crystal 35 and the surface of the melt 23, for example, it is surrounded by the heating portion 15a of the auxiliary heating means 15 of a resistance heating type. I have. At this time, in order to photograph the fusion ring with a diameter measuring camera, it is necessary to provide an opening for securing a camera view in a part of the heat generating portion 15a. In the auxiliary heating method, when heating the vicinity of the contact portion between the seed crystal 35 and the surface of the melt 23 with a resistance heater, the camera is used to increase the heating efficiency and widen the portion where the temperature gradient is small. It is desirable to narrow the opening for securing the visual field.
[0013]
[Patent Document 1]
JP-A-11-189488
[Patent Document 2]
JP 2001-27869A
[0014]
[Problems to be solved by the invention]
However, the narrower the opening of the resistance heating type heater is, the more the position of aligning the center of the seed crystal 35 with the center of the opening is required to photograph the fusion ring with a diameter measuring camera. It is necessary to improve the accuracy of the adjustment work. This position adjustment work is a careful and long-time work of a skilled worker, and causes problems such as a long preparation work and an increase in labor costs.
[0015]
If the center of gravity of the seed crystal 35 or the seed crystal holding part 24a is displaced from the rotation axis, when the seed crystal 35 is rotated, the seed crystal 35 vibrates like a rotary pendulum and stops on the rotation axis. You can not let it. At this time, the fusion ring moves, or the fusion ring moves out of the field of view of the opening of the resistance heating heater due to the movement, and it becomes difficult or impossible to photograph the fusion ring by the diameter measuring camera. As described above, when vibration occurs in the seed crystal 35, there is a problem that the accuracy of the measured value of the diameter of the neck 36a is deteriorated, or that the measurement itself becomes impossible.
[0016]
In addition, the seed crystal 35 is immersed in the melt 23 to melt a part of the seed crystal 35 using an auxiliary heating means to dislocate the seed crystal 35, thereby pulling the single crystal 36 without forming the neck 36a. When determining the temperature of the melt 23 and the speed at which the seed crystal 35 is immersed in the melt 23, it is essential to observe the state of formation of the fusion ring. In observing the formation state of the fusion ring at this time, it is desirable that the fusion ring can be observed in a wide range in a state as stable as possible.
[0017]
However, when the center axis of the seed crystal 35 is not aligned with the center axis of the heating part 15a of the auxiliary heating means 15, or in a state where the center of gravity of the seed crystal 35 or the seed crystal holding part 24a is off the rotation axis, When the seed crystal 35 is rotated, the seed crystal 35 vibrates like a rotary pendulum, and cannot be stopped on the rotation axis, and a state where the fusion ring cannot be sufficiently observed often occurs. As described above, when the fusion ring cannot be sufficiently observed, incorrect setting of the melt temperature and adjustment of the immersion speed of the seed crystal 35 may cause the dislocation-free seed crystal 35 to fail.
[0018]
In the above description, the case where the resistance heating type auxiliary heating means is used has been described as an example. However, the object of the present invention is not limited to the case where the auxiliary heating means is the resistance heating type. A similar problem exists when an auxiliary heating unit that controls the temperature distribution of the seed crystal by irradiating light to the site is used.
[0019]
The present invention has been made in view of the above problems, and facilitates adjustment of the position of a seed crystal and an auxiliary heating means, and can shorten the adjustment operation time. Even when vibrating like a rotary pendulum, the width of the vibration can be limited to a very small value, the heating efficiency by the auxiliary heating means can be improved, and the controllability of the temperature distribution generated in the seed crystal can be improved. It is an object of the present invention to provide a single crystal pulling apparatus that does not complicate the operation of retracting the auxiliary heating means before the diameter of the seed crystal is expanded and the main body is formed after the dislocation-free step. .
[0020]
Means for Solving the Problems and Their Effects
The present inventors affect the dislocation-free dislocation of the seed crystal during the dislocation removal of the seed crystal using the auxiliary heating means, and even if the seed crystal contacts the auxiliary heating means after the dislocation removal of the seed crystal. The present inventors have found that there is no dislocation and that dislocation-free seed crystals do not cause dislocations, and have completed the present invention.
[0021]
That is, in order to achieve the above object, a single crystal pulling apparatus (1) according to the present invention includes a seed crystal holding means for holding a seed crystal, a lifting / lowering means for raising / lowering the seed crystal holding means, and a main heater. Auxiliary heating means for partially heating the seed crystal and the surface of the melt, a moving means for moving the auxiliary heating means, the auxiliary heating means, and a power supply control means for controlling power supply to the main heater And a position control means for regulating the position of the seed crystal with respect to the auxiliary heating means.
[0022]
If the position control means is not provided, the position adjustment between the auxiliary heating means and the seed crystal in advance is incomplete, and the contact portion between the seed crystal and the melt is positioned with respect to the field of view of the camera for diameter measurement. According to the above-mentioned single crystal pulling apparatus (1), even if it is not located at the opening of the auxiliary heating means or if the seed crystal vibrates like a rotary pendulum with the rotation of the seed crystal, Due to the presence of the control means, even if the position adjustment of the seed crystal in advance is inadequate, the set position of the seed crystal can be accurately controlled to a desired position, and the center axis of the seed crystal can be controlled by the auxiliary heating. It can be accurately guided near the central axis of the means. Thus, the contact portion between the seed crystal and the melt with respect to the opening of the auxiliary heating means can be always included in the field of view of the diameter measuring camera. Further, even when vibration is generated due to rotation of the seed crystal, the width of the vibration can be narrowed, and the contact portion between the seed crystal and the melt can be prevented from coming off from the field of view of the diameter measuring camera.
[0023]
As described above, the contact portion between the seed crystal and the melt can be always observed with a diameter measuring camera, so that the seed crystal is brought into contact with the melt or immersed in the melt before the auxiliary heating. While heating the vicinity of the interface between the seed crystal and the melt using a means, a method of forming a neck having a diameter of 6 mm or more and pulling up the single crystal, or in advance, using the auxiliary heating means, the seed crystal and the After preheating the vicinity of the interface with the melt, the seed crystal is brought into contact with the melt, or immersed, and then the single crystal is pulled up by forming a neck having a diameter of 6 mm or more while continuously heating with the auxiliary heating means. The diameter control when forming the neck while heating the seed crystal by the auxiliary heating means can be stabilized.
[0024]
Further, after preheating near the interface between the seed crystal and the melt using the auxiliary heating means, the seed crystal is immersed in the melt while heating using the auxiliary heating means, and then a neck is formed. Instead, even in the method of pulling a single crystal, the seed crystal is immersed in the melt while being heated by the auxiliary heating means, and the control of the melt temperature and the control of the immersion speed can be reliably performed. You can do it.
[0025]
Further, according to the above-mentioned single crystal pulling apparatus (1), the position adjustment work between the seed crystal and the auxiliary heating means can be easily performed, the skill required for the position adjustment work is reduced, and the work time is reduced. Can be shortened, and production costs can be reduced.
[0026]
In addition, the single crystal pulling apparatus (2) according to the present invention is configured such that in the single crystal pulling apparatus (1), the position control means includes a movement amount restricting unit that regulates a horizontal movement amount of the seed crystal. It is characterized by being.
According to the single crystal pulling apparatus (2) described above, the above-described great effect can be obtained with a simple configuration.
[0027]
Further, in the single crystal pulling apparatus (3) according to the present invention, in the single crystal pulling apparatus (1), the position control means may move the seed crystal to a predetermined position of the position control means when the seed crystal descends. It is characterized by comprising a guide portion for guiding, and a movement amount restriction portion for restricting a horizontal movement amount of the seed crystal fixed below the guide portion.
According to the single crystal pulling apparatus (3) described above, the position control means is provided with the guide portion for guiding the seed crystal to a predetermined position of the position control means when the seed crystal descends. The position adjustment work between the crystal and the auxiliary heating means can be facilitated, the skill required for the position adjustment operation can be reduced, the operation time can be shortened, and the effect of reducing the production cost can be further ensured.
[0028]
Further, in the single crystal pulling apparatus (4) according to the present invention, in any one of the single crystal pulling apparatuses (1) to (3), an opening for enabling the position control means to retreat from the seed crystal is formed. It is characterized by being.
According to the single crystal pulling apparatus (4) described above, after the seed crystal dislocation-free operation by the auxiliary heating means is completed and before the crystal is expanded to a predetermined diameter, the position control means can be easily seeded. The single crystal can be retracted without adversely affecting the single crystal pulling step.
[0029]
In addition, the single crystal pulling apparatus (5) according to the present invention is the same as any one of the single crystal pulling apparatuses (1) to (4) above, wherein The position control means is fixed to an electrode for supplying electric power to the heat generating portion of the auxiliary heating means.
According to the above-mentioned single crystal pulling apparatus (5), after the work of displacing the seed crystal by the auxiliary heating means is completed, before the crystal is expanded to a predetermined diameter, the operation of collecting the position control means is performed. However, the operation can be performed in the same manner as in the case of using the conventional auxiliary heating means, and the recovery of the position control means does not adversely affect the single crystal pulling step.
[0030]
Further, the single crystal pulling apparatus (6) according to the present invention, in any one of the single crystal pulling apparatuses (1) to (5), includes the fixed portion of the movement amount limiting section and the electrode of the auxiliary heating means. And an insulating member is interposed therebetween.
According to the above-mentioned single crystal pulling apparatus (6), even if a conductive material is used as a constituent material of the position control means, it is possible to prevent a problem such as a short circuit between the auxiliary heating means and the electrode. be able to.
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a single crystal pulling apparatus according to the present invention will be described with reference to the drawings. Note that components having the same functions as those of the conventional example are denoted by the same reference numerals, and description thereof will be omitted.
The single crystal pulling apparatus according to the present embodiment is premised on pulling a single crystal having a large diameter and a large weight of 12 inches or more.
[0032]
FIG. 1 is a sectional view of a main part schematically showing a single crystal pulling apparatus according to the embodiment (1). FIGS. 2A and 2B show a position control means in the single crystal pulling apparatus. It is the top view and side view which showed the principal part containing typically.
[0033]
The single crystal pulling apparatus shown in FIG. 1 is provided with a position control means 18, and as shown in FIGS. 2 (a) and 2 (b), the position control means 18 has a hollow whose diameter increases vertically upward. A guide throat 18a having a substantially inverted conical shape is provided below the guide throat 18a. Below the guide throat 18a, a moving amount limiting portion 18b having a substantially disk shape is fixed, and the guide throat 18a and the moving amount limiting portion 18b have An opening 18c is formed for enabling the control means 18 to retreat from the seed crystal 35. More than half of the horizontal length of the seed crystal 35 in the horizontal direction is surrounded by the movement amount limiting portion 18b, so that the horizontal movement amount of the seed crystal 35 is limited. The position control means 18 is fixed to an electrode 15b for supplying electric power to the heating part 15a of the auxiliary heating means 15 via a fixing part 18d formed at the end of the movement amount restriction part 18b.
[0034]
The auxiliary heating means 15 is configured to include a heat generating portion 15a which can be positioned so as to surround the seed crystal 35 positioned immediately above the melt 23, and an electrode 15b for supplying electric power to the heat generating portion 15a. , The heat generating portion 15a and the position control means 18 are held by a moving mechanism 11A for retracting the heat generating portion 15a from the region where the single crystal 36 passes.
[0035]
As shown in FIG. 3, the moving mechanism 11A has a motor 11a, a pole screw 11b which is connected to the motor 11a and is driven to rotate as the motor 11a rotates, and an electrode 15b. An electrode holder 11c, which moves obliquely up and down in the axial direction of the pole screw 11b with the rotation of the pole screw 11b, and the pole screw 11b, the electrode holder 11c, and the electrode 15b are housed and fixed to the chamber 29. It is configured to include the cylinder 11d.
[0036]
In another embodiment, as shown in FIG. 4, a moving mechanism 11B is connected to a motor 11a and a pole screw which is connected to the motor 11a and is driven to rotate with the rotation of the motor 11a. -11b, an electrode holder 11f to which the electrode 15b is fixed and which moves obliquely up and down in the axial direction of the pole screw 11b with the rotation of the pole screw 11b, and a support fixed to the chamber 29 for supporting the motor 11a. It may be configured to include a plate 11e and a bellows 11g for accommodating the electrode 15b by separating the sealing plate 11h fixed to the chamber 29 and the electrode holder 11f from the surroundings.
[0037]
Further, in still another embodiment of the moving mechanism, a motor 11a and a pole screw 11b connected to the motor 11a and driven to rotate with the rotation of the motor 11a are replaced with a motor. Alternatively, a combination of an air cylinder and a piston may be used, or a device using a linear motor may be used.
[0038]
In still another embodiment, a gate valve is interposed between the chamber 29 and the cylinder 11d so that the entire auxiliary heating means 15 and the position control means 18 can be separated from the chamber 29. A configuration that facilitates the work may be adopted.
[0039]
By the guide throat 18a of the position control means 18, even when the center axis of the seed crystal 35 and the center axis of the heat generating portion 15a are largely displaced when the seed crystal 35 descends, the seed crystal 35 The stable position can be easily led to a position optimal for dislocation-free, and thereafter, the stable position of the seed crystal 35 can be maintained by the movement amount restricting portion 18b.
[0040]
The size of the opening 18c may be about 1.2 times the diameter of the neck 36a when a dislocation-free step of forming a neck 36a thinner than the seed crystal 35 and making it dislocation-free is adopted. When a predetermined length of the seed crystal 35 is immersed in the melt 23 to be melted, and a dislocation-free process is performed to eliminate dislocation without forming the neck 36a, the diameter of the seed crystal 35 is about 1.10. It is sufficient if it is twice or more. The presence of the opening 18c allows the position control means 18 to smoothly retreat from the seed crystal 35.
[0041]
The presence of the position control means 18 guides the stable position of the seed crystal 35 to an optimal position for dislocation-free, and can maintain the stable position. Therefore, the aperture ratio of the heat generating portion 15a for controlling the seed crystal diameter is controlled. (The ratio of the angle formed by the opening of the heat generating portion 15a in the horizontal plane as viewed from the central axis of the seed crystal 35) can be significantly reduced, and the seed crystal 35 (or the neck 36a) grown during the dislocation-free step can be reduced. An opening configuration of about 1.2 times the diameter of ()) is also possible.
[0042]
As a constituent material of the position control means 18, ceramics having excellent insulation properties and high-temperature durability can be used. Ceramics can be used alone.
[0043]
Further, by combining quartz which is excellent in insulation properties but inferior in high-temperature durability and a molded heat insulating material obtained by solidifying carbon fibers, the position control means 18 excellent in insulation properties and high-temperature durability can be constituted. . Both have been used as furnace components for a long time, and are less likely to cause heavy metal contamination.
[0044]
In addition, by combining a high melting point metal such as graphite, molybdenum, and tungsten with excellent high temperature durability and quartz or ceramics with excellent electrical insulation, the position control means 18 with excellent insulation and high temperature durability can be provided. Can be configured. Graphite also has the advantage of being easy to process.
[0045]
In addition, the single crystal pulling apparatus shown in FIG. 1 includes an image processing unit 12 having an imaging unit capable of monitoring a change in the diameter of a crystal grown when displacing the seed crystal 35, a seed crystal diameter control unit The seed crystal diameter control means 16 includes a power supply control means 13 for the auxiliary heating means 15, a power supply control means 9 for the main heater 22, and a raising / lowering speed control means 14 for the seed crystal 35. And receives the fluctuation information of the diameter of the seed crystal 35 detected by the image processing means 12 and automatically controls the diameter of the seed crystal 35 to be maintained at a desired value based on this information. I have.
[0046]
FIG. 5 is a plan view schematically showing the position control means 18A according to the embodiment (2). The position control means 18A assists the opening 18c for retreating from the seed crystal 35 and the position control means 18A. In addition to a fixing portion 18d for fixing the electrode 15b that supplies power to the heating means 15, an insulating washer 18e and an insulating sleeve 18f are further provided to insulate the position control means 18A from the electrode 15b.
[0047]
According to the position control means 18A according to the embodiment (2) shown in FIG. 5, even if any material is selected as the constituent material of the guide throat 18a and the movement amount restricting portion 18b which come into contact with the seed crystal 35, the position control is performed. Since the insulating property between the means 18A and the electrode 15b is ensured, no electric trouble occurs even if the position control means 18A is additionally provided.
[0048]
FIG. 6 is a plan view schematically showing the position control means 18B according to the embodiment (3). The position control means 18B according to the embodiment (3) is different from the position control means 18 shown in FIG. The point that the guide throat 18a having a hollow substantially inverted conical shape whose diameter increases vertically upward in contact with the seed crystal 35 is not provided. The other configuration is the same as that of the position control unit 18 shown in FIG. 2, and the detailed description is omitted here. The position control means 18B has been developed mainly for limiting vibration generated by rotating the seed crystal 35, and is characterized in that it has a simple structure and can be manufactured at low cost.
[0049]
Next, a single crystal pulling method using the above single crystal pulling apparatus will be described.
FIGS. 7A to 7E are partial cross-sectional enlarged front views schematically showing the vicinity of the seed crystal 35 when performing some of the steps of pulling the single crystal 36. is there.
First, after the seed crystal 35 is brought into contact with or immersed in the melt 23, power is supplied to the heat generating portion 15 a of the auxiliary heating means 15 to form the neck 36 a while heating the seed crystal 35 to eliminate dislocation. explain.
[0050]
Steps before the steps described below are performed in the same manner as the method described in the section of “Prior Art”.
First, the seed crystal 35 attached to the holder 24a (FIG. 9) is lowered to just above the melt 23 without rotating, and the seed crystal 35 is preheated. At this time, the reason why the seed crystal 35 is not rotated is that if the position of the center of gravity formed by the seed crystal 35 and the holder 24a is shifted from the rotation axis, rotating the holder 24a causes the seed crystal 35 to rotate. This is because, when a vibration in the form of a rotating pendulum occurs and an amplitude having a magnitude that cannot be controlled by the position control means 18 is generated, it is difficult to lower the seed crystal 35.
[0051]
At this time, even if the center axis of the seed crystal 35 does not coincide with the center axis of the heat generating portion 15a of the auxiliary heating means 15, even if it has been impossible to guide the seed crystal 35 to the optimal position in the related art, By the presence of the control means 18, the seed crystal 35 can be guided to the optimum position (FIGS. 7A and 7B).
[0052]
Next, the seed crystal 35 is brought into contact with the melt 23, and the pull-up shaft 24 is rotated at a predetermined speed in the opposite direction to the same axis as the support shaft 28 (FIG. 9). The power is supplied to the auxiliary heating means 15 and the power supplied to the main heater 22 is adjusted to adjust the temperatures of the seed crystal 35 and the melt 23 to the optimum temperature. At this time, it is determined whether or not the temperature of the melt 23 is appropriate based on the degree of curvature of the melt 23 due to the surface tension generated around the contact interface between the seed crystal 35 and the melt 23. The power supplied to the main heater 22 is adjusted, and the temperature of the melt 23 is adjusted.
[0053]
In order to stabilize the temperature of the melt 23, for example, when the weight of the melt 23 is about 200 kg, it takes about 2 hours after the main heater power is operated. It becomes. If the weight of the melt 23 is further increased, the heat capacity of the melt 23 increases, so that the time required for stabilizing the melt temperature of the melt 23 also becomes longer. It is important for the quality control of the single crystal 36 to be pulled to set a time for sufficiently stabilizing the liquid temperature before moving to the next process.
[0054]
Next, a neck 36a for dislocation-free seed crystal 35 is grown. In order to make the crystal dislocation-free, it is preferable that the diameter of the neck 36a is small. The danger increases. On the other hand, if the diameter of the neck 36a is increased, it is disadvantageous for eliminating dislocations in the crystal. When the auxiliary heating means 15 is used, it is desirable that the diameter of the neck 36a grown for dislocation-free is set to a value in the range of 6 to 10 mm. If the diameter of the neck 36a is grown in the range of 6 to 10 mm, dislocation-free can be achieved, and the diameter of the seed crystal 35 is not affected. In the crystal growth for eliminating dislocations, the diameter of the neck 36a being grown is measured by the image processing means 12 in order to control the diameter of the neck 36a.
[0055]
Conventionally, even when the seed crystal 35 vibrates due to the rotation and the measurement of the diameter of the neck 36a becomes impossible, the single crystal pulling apparatus according to the embodiment can be used. Due to the presence of the position control means 18, the diameter of the neck 36a is measured stably without the contact portion between the neck 36a and the melt 23 moving from the opening of the heat generating portion 15a to an unobservable position. be able to. In addition, even when the vibration caused by the rotation of the seed crystal 35 is generated, the width of the vibration is narrowed, and it is possible to prevent the contact portion between the seed crystal 35 and the melt 23 from coming out of the field of view of the diameter measuring camera, thereby stably. The diameter of the neck 36a can be measured.
[0056]
Next, the power supply to the auxiliary heating means 15 is stopped, and the position control means 18 is retreated from the periphery of the neck 36a at the same time as the heat generating portion 15a. (About inch) (FIG. 7D). Thereafter, the single crystal 36 is pulled up at a predetermined pulling speed to form the main body 36c (FIG. 7E).
[0057]
Thereafter, the single crystal 36 is pulled up by a method similar to the method described in the section of “Prior Art”, separated from the melt 23 and cooled. Thereafter, outside the system, the neck 36a is cut using a tool such as a nipper, and the single crystal 36 is cut off from the seed crystal 35 to complete the pulling of the single crystal 36.
[0058]
Also, after supplying power to the auxiliary heating means 15 to sufficiently preheat the seed crystal 35, the seed crystal 35 is heated or brought into contact with or immersed in the melt 23, and then the neck 36a is heated while heating the vicinity of the contact interface. Also, in the case of dislocation-free by forming the above, after the above-described seed crystal 35 is brought into contact with or immersed in the melt 23, power is supplied to the auxiliary heating means 15 to heat the seed crystal 35 while the neck 36 a is heated. The single crystal 36 can be pulled up in substantially the same manner as in the case of forming dislocations and eliminating dislocations.
[0059]
Next, using the above-described single crystal pulling apparatus, before dipping the seed crystal 35 in the melt 23, power is supplied to the auxiliary heating means 15, and the seed crystal 35 is sufficiently preheated and then dipped in the melt 23. Thereafter, a case where the single crystal 36 is grown without forming a neck will be described. In this method, a seed crystal 35 having a diameter of about 6 to 10 mm is used.
[0060]
Steps before the steps described below are performed in the same manner as the method described in the section of “Prior Art”.
The auxiliary heating power determined empirically in advance and the main heater power similarly determined empirically are supplied to the auxiliary heating means 15 and the main heater 22, and the temperature of the melt 23 and the temperature of the auxiliary heating means 15 are measured. Set to the optimal temperature that was found in the future.
[0061]
Next, the seed crystal 35 attached to the holder 24a (FIG. 9) is lowered to just above the melt 23 without rotating, and the seed crystal 35 is preheated (FIG. 8B).
[0062]
At this time, even if the center axis of the seed crystal 35 does not coincide with the center axis of the heat generating portion 15a of the auxiliary heating means 15, even if it has been impossible to guide the seed crystal 35 to the optimal position in the related art, By the presence of the control means 18, the seed crystal 35 can be guided to the optimum position (FIGS. 8A and 8B).
[0063]
The preheating here is 10 minutes or more in order to improve the quality of the crystal grown thereafter. Next, the seed crystal 35 is brought into contact with the melt 23, and the pull-up shaft 24 is rotated at a predetermined speed in the same axis as the support shaft 28 and in the opposite direction to stabilize the temperature of the seed crystal 35 and the melt 23. At this time, it is determined whether or not the temperature of the melt 23 is appropriate based on the degree of curvature of the melt 23 due to the surface tension generated around the contact interface between the seed crystal 35 and the melt 23. The power supplied to the main heater 22 is adjusted, and the temperature of the melt 23 is adjusted.
[0064]
Next, the seed crystal 35 is immersed in the melt 23 by a length at least about three times the diameter of the neck 36 a of the seed crystal 35, and is generated and introduced by a thermal shock when the seed crystal 35 is brought into contact with the melt 23. The dislocations are removed, and the crystal is rendered dislocation-free.
[0065]
At the time of dislocation-free, in the step of immersing the seed crystal 35 in the melt 23, in order to control the temperature of the melt 23 and the seed crystal 35, around the contact portion between the seed crystal 35 and the melt 23 Observe the shape of the curved portion formed due to surface tension.
[0066]
Conventionally, even when the seed crystal 35 vibrates due to the rotation and the measurement of the diameter of the neck 36a becomes impossible, the single crystal pulling apparatus according to the embodiment can be used. Due to the presence of the position control means 18, the diameter of the neck 36a is measured stably without the contact portion between the neck 36a and the melt 23 moving from the opening of the heat generating portion 15a to an unobservable position. be able to. In addition, even when the vibration caused by the rotation of the seed crystal 35 is generated, the width of the vibration is narrowed, and it is possible to prevent the contact portion between the seed crystal 35 and the melt 23 from coming out of the field of view of the diameter measuring camera, thereby stably. The diameter of the neck 36a can be measured.
[0067]
Thereafter, the diameter can be immediately increased without forming a neck, and the single crystal 36 can be grown, but in order to recover the length of the seed crystal 35 shortened by immersion and to avoid a sudden change in the thermal environment, It is desirable to grow a straight body portion 37 having substantially the same diameter as the diameter of the seed crystal 35 by about 5 times the diameter of the seed crystal 35 while heating using the auxiliary heating means 15.
Also in the growth of the straight body 37, the diameter of the neck 36a of the growing straight body 37 is measured by the image processing means 12 in order to accurately control the diameter.
[0068]
Conventionally, the single crystal pulling apparatus according to the embodiment can be used even in a case where the seed crystal 35 vibrates due to the rotation and the measurement of the diameter of the straight body 37 becomes impossible. For example, due to the presence of the position control means 18, the contact portion between the straight body portion 37 and the melt 23 does not move from the opening of the heat generating portion 15a to an unobservable position, and the straight body portion is stably 37 diameter measurements can be made. In addition, even when vibration occurs due to rotation of the seed crystal 35, the width of the vibration is narrowed, and it is possible to prevent the contact portion between the straight body portion 37 and the melt 23 from coming out of the field of view of the diameter measuring camera, thereby stabilizing. Measurement of the diameter of the straight body portion 37.
[0069]
Next, the power supply to the auxiliary heating means 15 is stopped, and the position control means 18 is retracted from the periphery of the straight body 37 at the same time as the heating section 15a, and then the shoulder 36b is formed without forming a neck, The single crystal 36 is grown to a predetermined diameter (about 12 inches) (FIG. 8D). Thereafter, the single crystal 36 is pulled up at a predetermined pulling speed to form the main body 36c (FIG. 8E).
[0070]
Thereafter, the single crystal 36 is pulled up by a method similar to the method described in the section of “Prior Art”, separated from the melt 23 and cooled. After that, outside the system, the vicinity of the lower end 37a of the straight body 37 is cut using a tool such as a nipper, and the single crystal 36 is separated from the seed crystal 35 and the straight body 37 to complete the pulling of the single crystal 36. .
The seed crystal 35 and the straight body portion 37 are used as a seed crystal in the next pulling of the single crystal.
[0071]
In the above embodiment, the case where the CZ method is applied has been described. However, the present invention is not limited to the application to the CZ method at all, and is similarly applicable to, for example, the MCZ method for supplying a magnetic field.
[0072]
In the above embodiment, the case where the seed crystal 35 has a substantially cylindrical shape has been described. However, in another embodiment, the seed crystal may have a polygonal column shape. It may be about 6 to 10 mm.
[0073]
[Examples and Comparative Examples]
Hereinafter, the single crystal pulling methods according to the examples and the comparative examples will be described. The conditions are described below.
<Conditions Common to Examples and Comparative Examples>
Shape of single crystal 36 to be pulled
Diameter: about 300mm (12 inches), length: about 1100mm
Weight: about 215kg
Crystal raw material charge: approx. 240 kg
Inner diameter of crucible 21: 30 inches
Atmosphere in chamber 29: Ar atmosphere
Ar flow rate: 100 l / min
Pressure: 1.33 × 10 ³ Pa
Rotation speed of lifting shaft 24: 6 rpm
Rotation speed of crucible 21: 5 rpm
Shape of seed crystal 35
Diameter D: 8mm, length: 300mm
<Conditions Common to First Embodiment>
After the seed crystal 35 was brought into contact with the melt 23, a neck 36a (L = 150 mm) was formed, and the single crystal 36 was subsequently pulled up. During the formation of the neck 36a, the position of the neck 36a was controlled by the position control means 18 when heating was performed by the auxiliary heating means 15. The single crystal 36 was pulled up ten times.
<Conditions Common to Comparative Example 1>
After the seed crystal 35 was brought into contact with the melt 23, a neck 36a (L = 150 mm) was formed, and the single crystal 36 was subsequently pulled up. During the formation of the neck 36a, the position of the neck 36a is not controlled by the position control unit 18 when heating is performed by the auxiliary heating unit 15. The single crystal 36 was pulled up ten times.
[0074]
The results of Example 1 and Comparative Example 1 are shown in Table 1 below.
[Table 1]

[0075]
In the case of Example 1, the image processing means 12 does not lose sight of the interface between the neck 36a and the melt 23 in the formation of the neck 36a for eliminating dislocations in any of the ten times of pulling of the single crystal 36. The automatic control of the diameter never failed. Further, in the pulling of all the single crystals 36, dislocation-free operation was successful, and a main body portion 36c having a predetermined length was formed.
[0076]
On the other hand, in the case of Comparative Example 1, the diameter of the neck crystal 36a cannot be automatically measured due to the vibration of the seed crystal 35 during the seven times of pulling of the single crystal 36 out of the ten times of pulling of the single crystal 36. I can no longer do it. The operator was able to form the neck 36a by manually controlling the diameter of the neck 36a five times out of seven times, but three times succeeded in dislocation-free, and the remaining two times were dislocation-free. And the pulling of the single crystal 36 failed. In the pulling of the single crystal 36 in which the diameter measurement of the neck 36 a became impossible, two times of the failure of manual control of the neck 36 a failed, and the single crystal 36 was separated from the melt 23. The pulling of the single crystal 36 for which the diameter of the neck 36a could be measured three times succeeded in eliminating dislocations. In the final 10 pull-ups of the single crystal 36, the predetermined main body 36c could be grown without dislocation six times.
[0077]
As described above, when the auxiliary heating device 15c is used, by using the position control means 18 according to the embodiment together, it is possible to shorten the operation time of the operation of aligning the position of the seed crystal 35 and the holder 24a, and reduce It was found that the work impossible at the time of pulling the crystal 36 was reduced and the success rate of pulling the single crystal 36 was greatly improved.
<Conditions Common to Second Embodiment>
Electric power is supplied to the auxiliary heating device 15 in advance, and the seed crystal 35 is sufficiently heated before being brought into contact with the melt 23. Subsequently, after the seed crystal 35 is brought into contact with the melt 23, a neck 36a (L = 150 mm) is formed, and then the single crystal 36 is pulled up. During the formation of the neck 36a, the position of the neck 36a was controlled by the position control means 18 when heating was performed by the auxiliary heating means 15. The single crystal 36 was pulled five times.
<Conditions Common to Comparative Example 2>
Electric power is supplied to the auxiliary heating means 15 in advance, and the seed crystal 35 is sufficiently heated before being brought into contact with the melt 23. Subsequently, after the seed crystal 35 is brought into contact with the melt 23, a neck 36a (L = 150 mm) is formed, and then the single crystal 36 is pulled up. During the formation of the neck 36a, the position of the neck 36a was not controlled by the position control unit 18 when heating was performed by the auxiliary heating unit 15. The single crystal 36 was pulled five times.
[0078]
The results of Example 2 and Comparative Example 2 are shown in Table 2 below.
[Table 2]

[0079]
In the case of the second embodiment, in any of the five times of pulling of the single crystal 36, in forming the neck 36 a for eliminating dislocation, the image processing unit 12 does not lose sight of the interface portion between the neck 36 a and the melt 23, Automatic control of the 36a diameter did not fail. In the pulling of all the single crystals 36, dislocation-free was successfully achieved, and a main body portion 36c having a predetermined length was formed.
[0080]
On the other hand, in the case of Comparative Example 2, when the single crystal 36 was pulled three times out of the five times, the diameter of the neck 36a could not be measured due to the vibration of the seed crystal 35. I lost control. The operator was able to form the neck 36a by controlling the diameter of the neck 36a manually two times out of the three times, but only one was successfully dislocation-free, and the other one was a dislocation-free single crystal. Failed to raise 36. In the pulling of the single crystal 36 in which the diameter measurement of the neck 36 a becomes impossible, the control of the neck 36 a by manual operation failed, and the single crystal 36 was separated from the melt 23. The pulling of the single crystal 36 for which the diameter measurement of the neck 36a was possible twice succeeded in eliminating dislocations. Finally, three of the five pull-ups of the single crystal 36 were able to grow the predetermined main body 36c without dislocations.
[0081]
When the auxiliary heating means 15 is used as described above, by using the position control means 18 according to the embodiment together, it is possible to reduce the work time for aligning the positions of the seed crystal 35 and the holder 24a and reduce the time required for the single crystal. It was found that the work impossible at the time of pulling the 36 was reduced, and the success rate of pulling the single crystal 36 was greatly improved.
<Conditions Common to Third Embodiment>
Electric power is supplied to the auxiliary heating means 15 in advance, and the seed crystal 35 is sufficiently heated before being brought into contact with the melt 23. Subsequently, after the seed crystal 35 is immersed in the melt 23, a straight body portion 37 (L2 = 50 mm) is formed, and then the single crystal 36 is pulled up. The position of the seed crystal 35 was controlled by the position control means 18 when the auxiliary heating means 15 was used to heat the straight body portion 37 while being pulled up. The single crystal 36 was pulled five times.
<Conditions Common to Comparative Example 3>
Electric power is supplied to the auxiliary heating means 15 in advance, and the seed crystal 35 is sufficiently heated before being brought into contact with the melt 23. Subsequently, after the seed crystal 35 is immersed in the melt 23, a straight body portion 37 (L2 = 50 mm) is formed, and then the single crystal 36 is pulled up. When the heating was performed by the auxiliary heating means 15 while raising the straight body portion 37, the position control of the seed crystal 35 by the position control means 18 was not performed. The single crystal 36 was pulled five times.
[0082]
Table 3 below summarizes the results of Example 3 and Comparative Example 3.
[Table 3]

[0083]
In the case of the third embodiment, in any of the five times of pulling of the single crystal 36, in forming the straight body portion 37 for dislocation-free, the image processing unit 12 uses the interface between the straight body portion 37 and the melt 23. There was no failure in automatic control of the diameter of the straight body 37 without losing the part. In the pulling of all the single crystals 36, dislocation-free was successfully achieved, and a main body portion 36c having a predetermined length was formed.
[0084]
In Comparative Example 3, the measurement of the diameter of the straight body 37 was impossible due to the vibration of the seed crystal 35 in the two times of pulling of the single crystal 36 during the five times of pulling of the single crystal 36. Automatic control is no longer possible. When the operator manually controlled the diameter of the straight body 37, the straight body 37 could be formed once, but the dislocation could not be eliminated. In the remaining one time, the diameter control of the straight body portion 37 failed, and the crystal was separated from the melt 23. Of the three pull-ups of the single crystal 36 capable of measuring the diameter of the straight body portion 37, two failed to eliminate dislocations. Eventually, of the five times of pulling the single crystal 36, only one was able to grow a predetermined main body 36c without dislocation.
[0085]
As described above, when the auxiliary heating means 15 is used, by using the position control means 18 according to the embodiment together, it is possible to reduce the work time for aligning the positions of the seed crystal 35 and the holder 24a, The work load in pulling the crystal 36 was reduced, and the success rate of pulling the single crystal 36 was significantly improved.
[0086]
Next, an example in which a high-melting point metal is used for forming the position control means 18 and the position control means 18 is joined to the electrode 15b of the auxiliary heating means 15 via an insulating sleeve and an insulating washer will be introduced.
<Conditions Common to Example 4>
Electric power is supplied to the auxiliary heating means 15 in advance, and the seed crystal 35 is sufficiently preheated before being brought into contact with the melt 23. Subsequently, after the seed crystal 35 is brought into contact with the melt 23, a neck 36a (L = 150 mm) is formed, and then the single crystal 36 is pulled up. During the formation of the neck 36a, the position of the neck 36a was controlled by the position control means 18 when heating was performed by the auxiliary heating means 15. The single crystal 36 was pulled five times.
[0087]
The results are shown in Table 4 below.
[Table 4]

[0088]
In the case of the fourth embodiment, the image processing unit 12 does not lose sight of the interface between the neck 36a and the melt 23 in the formation of the neck 36a for eliminating dislocations in any of the five times of pulling the single crystal 36. The automatic control of the diameter of the neck 36a did not fail. In the pulling of all the single crystals 36, dislocation-free was successfully achieved, and a main body portion 36c having a predetermined length was formed. Also, there was no induction of electrical trouble in the auxiliary heating means 15.
[0089]
In the above Examples 1, 2, 3, and 4 and Comparative Examples 1, 2, and 3, one of the necks was successful in measuring the diameter of the neck 36a or the diameter of the straight body portion 37 and successfully pulling the single crystal 36. Although the measurement of the diameter of the 36a or the diameter of the straight body portion 37 failed, 0.5 points were given to those who succeeded in pulling the single crystal 36, and 0 points were given to those that failed to pull the single crystal 36. Examples and Comparative Examples Table 5 below shows a result of multiplying the sum of the respective values by the number of experiments and multiplying the result by 100.
[0090]
[Table 5]

Table 5 clearly shows the effect of the present invention.
[0091]
Note that the crystal quality of a crystal in which the single crystal 36 having the dislocation-free main body 36c was successfully pulled was measured. As a result, it became clear that there was no difference in the quality of the crystal such as the lifetime between the example and the comparative example.
[Brief description of the drawings]
FIG. 1 is a schematic partial cross-sectional view showing a main part of a single crystal pulling apparatus according to an embodiment of the present invention.
FIG. 2A is a partially enlarged plan view showing a main part of a single crystal pulling apparatus according to an embodiment, and FIG. 2B is a partially enlarged side view.
FIG. 3 is a partially enlarged side sectional view showing a main part of the single crystal pulling apparatus according to the embodiment.
FIG. 4 is a partially enlarged side sectional view showing a main part of a single crystal pulling apparatus according to another embodiment.
FIG. 5 is a partially enlarged plan view showing a main part of a single crystal pulling apparatus according to another embodiment.
FIG. 6A is a partially enlarged plan view showing a main part of a single crystal pulling apparatus according to still another embodiment, and FIG. 6B is a partially enlarged side view.
FIGS. 7A to 7E are schematic views showing the vicinity of a seed crystal when performing a part of a single crystal pulling process using the single crystal pulling apparatus according to the embodiment; FIG. 2 is an enlarged partial cross-sectional front view shown in FIG.
FIGS. 8A to 8E are schematic views showing the vicinity of a seed crystal when a part of a single crystal pulling process using a single crystal pulling apparatus according to an embodiment is performed. FIG. 2 is an enlarged partial cross-sectional front view shown in FIG.
FIG. 9 is a schematic partial sectional view showing a main part of a conventional single crystal pulling apparatus.
FIGS. 10A to 10D schematically show the vicinity of a seed crystal when performing a part of a single crystal pulling process using a conventional single crystal pulling apparatus. It is a partial section enlarged front view.
[Description of sign]
12 Image processing means
13 Power supply control means
14 Elevation speed control means
15 Auxiliary heating means
15a Heating part
15b electrode
16 Seed crystal diameter control means
18 Position control means
18a Information slot
18b Movement limiter
18c opening
18d fixed part
21 crucible
22 Main heater

Claims (6)

Seed crystal holding means for holding a seed crystal,
Elevating means for elevating the seed crystal holding means,
Auxiliary heating means for partially heating the seed crystal and the melt surface separately from the main heater;
Moving means for moving the auxiliary heating means,
A single crystal pulling apparatus comprising: an auxiliary heating means; and a power supply control means for controlling power supply to the main heater.
A single crystal pulling apparatus comprising a position control means for regulating a position of the seed crystal with respect to the auxiliary heating means. 2. The single crystal pulling apparatus according to claim 1, wherein the position control means includes a movement amount restricting unit that restricts a horizontal movement amount of the seed crystal. The position control means guides the seed crystal to a predetermined position of the position control means when the seed crystal descends, and regulates a horizontal movement amount of the seed crystal fixed below the guide part. 2. The single crystal pulling apparatus according to claim 1, further comprising a moving amount restricting section that moves. The single crystal pulling apparatus according to any one of claims 1 to 3, wherein an opening for allowing the position control means to retreat from the seed crystal is formed. The position control means is fixed to an electrode for supplying electric power to a heat generating part of the auxiliary heating means via a fixing part formed at an end of the movement amount restricting part. 5. The single crystal pulling apparatus according to any one of Items 4 to 4. The insulating member is interposed between the fixed portion of the movement amount limiting portion and the electrode of the auxiliary heating means, according to any one of claims 1 to 5, wherein Single crystal pulling device.

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