JPS6217096A - Magnetic field impressing device for drawing up single crystal - Google Patents

Abstract

PURPOSE:To obtain the titled device capable of both a horizontal magnetic field and a vertical magnetic field with one unit of device wherein two units of devices are necessitated in a convertional method by winding mutually the first and the second electromagnetic coils crossly on the outside periphery of the device for drawing up single crystal. CONSTITUTION:When exciting current Ia and Ib having the same magnitude are respectively conducted through the first and the second coils 12a, 12b, the magnetic fields Ha, Hb having same intensity are generated in the inside of a crucible 4 with each oil 12a, 12b and a horizontal magnetic field Hb is formed as a synthetic magnetic field of both magnetic fields Ha, Hb. Also when changing over the direction of the exciting current Ib of the second coil 12b to the reverse direction, the direction of the magnetic field Hb is inversed in 180 deg. and a vertical magnetic field Hv is formed as the synthetic magnetic field. In such a way, the changeover of the horizontal magnetic field Hh and the vertical magnetic field Hv can easily be performed only by changing over the directions of the exciting current Ia, Ib of the coils 12a, 12b.

Description

【発明の詳細な説明】 〔発明の技術分野〕 本発明は、主にシリコンやガリウムひ素等の半導体単結
晶引上装置で使用される１１弄印加装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an 11-temperature applying device mainly used in a device for pulling semiconductor single crystals of silicon, gallium arsenide, etc.

〔従来技術とその問題点〕[Prior art and its problems]

近年、チョクラルスキー法により単結晶を引き上げる際
に、水平方向の静磁界を印加して融液の熱対流を抑える
事により、融液温度を安定させかつルツボ壁からの汚染
を減少させて単結晶の品質向上を計るということが行な
われている。In recent years, when pulling a single crystal using the Czochralski method, a horizontal static magnetic field is applied to suppress the thermal convection of the melt, thereby stabilizing the melt temperature and reducing contamination from the crucible wall. Efforts are being made to improve the quality of crystals.

このための従来の磁界印加装置は、第４図にその断面構
造を示すように、引上装置チャンバ１の水平方向外側に
このチャンバ１をはさんで対向するように設けられた２
つの電磁コイル２ａ、２ｂと、引上装置チャンバ１の外
周を半周して両コイル２ａ、　２ｂの磁路をつなぐ鉄心
３とから成る直流電磁石により構成され、引上装置チャ
ンバ１の内部に置かれたルツボ４内の単結晶原料融液５
に直流水平磁界Ｈを印加するものである。A conventional magnetic field application device for this purpose, as shown in its cross-sectional structure in FIG.
It is composed of a DC electromagnet consisting of two electromagnetic coils 2a and 2b and an iron core 3 that goes half around the outer circumference of the pulling device chamber 1 and connects the magnetic path of both coils 2a and 2b, and is placed inside the pulling device chamber 1. Single crystal raw material melt 5 in crucible 4
A DC horizontal magnetic field H is applied to the

ところで、融液５に印加する磁界の方向は水平方向が最
良とは限らず単結晶の種類や製造条件等によっては鉛直
方向の方が好ましい場合もあり、このような場合には上
記のような水平磁界型の装置は使用できないため鉛直磁
界型の装置に交換する必要がある。By the way, the horizontal direction is not necessarily the best direction for the magnetic field to be applied to the melt 5, and depending on the type of single crystal, manufacturing conditions, etc., the vertical direction may be preferable. Since horizontal magnetic field type devices cannot be used, it is necessary to replace them with vertical magnetic field type devices.

ところが、上記のように引上装置チャンバ１の外側にコ
イル２ａ、２ｂと鉄心３とを配した従来装置は非常に大
きい重囲を有するため交換を容易に行なえないという問
題がある。However, the conventional device in which the coils 2a, 2b and the iron core 3 are disposed outside the pulling device chamber 1 as described above has a problem in that it cannot be easily replaced because it has a very large enclosure.

例えば、第３図（ａ）及び＜ｂ）はルツボ４内に２　ｋ
Ｇｓ　、３　ｋＧｓ及び４　ｋＧｓの各磁束密度を発生
させる従来の磁界印加装置における鉄心３およびコイル
２ａ、２ｂの重量をコイル２ａ、２ｂ間距離との関係で
示したものであるが、同図によれば一般によく用いられ
るコイル２ａ、２ｂ間距離が９００ｍで磁束密度が３　
ｋＧｓ〜４　ｋＧｓの装置の場合、鉄心３は２０ｔ〜３
０ｔ、コイル２ａ、２ｂは２ｔ〜３ｔにもなることが分
かる。従って、このように数１０ｔもある装置を交換す
ることは大変な作業となる。For example, in Fig. 3(a) and <b), 2 k
The weights of the iron core 3 and the coils 2a, 2b in a conventional magnetic field application device that generates magnetic flux densities of 3 kGs, 3 kGs, and 4 kGs are shown in relation to the distance between the coils 2a, 2b. According to the generally used coils 2a and 2b, the distance between them is 900 m and the magnetic flux density is 3.
In the case of kGs~4 kGs equipment, the iron core 3 is 20t~3
0t, and it can be seen that the coils 2a and 2b have a length of 2t to 3t. Therefore, replacing a device weighing several tens of tons like this is a difficult task.

なお、この装置の重量の大部分は鉄心３であるため、鉄
心３を無くし代りにコイル２ａ、２ｂの巻数を約２倍と
すれば同じ磁束密度で約５分の１の重量に軽量化するこ
とができると考えられるが、］イル２ａ、２ｂは冷却の
ために中空導体を使用する等の事情からもともとかなり
寸法の大きいものであるため、巻数を２倍に増加するこ
とはコイル寸法が極めて大きくなって非常に広いスペー
スを要することとなり現実的ではない。Furthermore, since most of the weight of this device is the iron core 3, if the iron core 3 is eliminated and the number of turns of the coils 2a and 2b is doubled instead, the weight can be reduced to about one-fifth with the same magnetic flux density. However, coils 2a and 2b are already quite large due to the use of hollow conductors for cooling, so doubling the number of turns would be extremely difficult to increase the coil dimensions. It becomes large and requires a very large space, which is not practical.

しかも、このような従来の装置は、水平磁界型と鉛直磁
界型の２種類の装置を用意しなければならないという本
質的な欠点を有している。Moreover, such conventional devices have an essential drawback in that two types of devices, a horizontal magnetic field type and a vertical magnetic field type, must be prepared.

〔発明の目的〕[Purpose of the invention]

本発明は、上記問題点に鑑みなされたもので、水平磁界
も鉛直磁界も１台の装置で発生させることができ従来の
ような装置交換の必要がない単結晶引上用磁界印加装置
を提供することを目的とする。The present invention has been made in view of the above-mentioned problems, and provides a magnetic field application device for pulling a single crystal, which can generate both a horizontal magnetic field and a vertical magnetic field with one device, and eliminates the need to replace devices as in the past. The purpose is to

〔発明の概要〕[Summary of the invention]

上記目的を達成するため、本発明は単結晶引上装置の外
周に、この引上装置に印加すべき磁界の方向に対して傾
斜させて１又は２以上の第１の電磁コイルを巻き、更に
、前記磁界の方向に対して前記第１の電磁コイルとは反
対方向へ傾斜させて１又は２以上の第２の電磁コイルを
巻いたものである。In order to achieve the above object, the present invention winds one or more first electromagnetic coils around the outer periphery of a single crystal pulling device so as to be inclined with respect to the direction of the magnetic field to be applied to the pulling device. , one or more second electromagnetic coils are wound so as to be inclined in a direction opposite to that of the first electromagnetic coil with respect to the direction of the magnetic field.

〔発明の実施例〕[Embodiments of the invention]

以下、実施例により本発明を説明する。 The present invention will be explained below with reference to Examples.

第１図は本発明に係る磁界印加装置の一実施例の構成と
作用とを示す斜視図であり、第５図と同一物には同一符
号を付しである。FIG. 1 is a perspective view showing the structure and operation of an embodiment of the magnetic field application device according to the present invention, and the same parts as in FIG. 5 are given the same reference numerals.

第１図において、例えば円筒状をなす引上装置チャンバ
１の外周に、水平方向に対し所定角度傾斜して第１の電
磁コイル１２ａが所定ターン数巻かれており、水平方向
に対し第１のコイル１２ａとは反対方向へ同角度だけ傾
斜して第２の電磁コイル１２ｂが同ターン数巻かれてい
る。従って、第１のコイル１２ａと第２のコイル１２ｂ
とはた寸きかけのように交差してチャンバ１の外周に巻
かれていることになり、この両コイル１２ａ。In FIG. 1, for example, a first electromagnetic coil 12a is wound around the outer periphery of a cylindrical lifting device chamber 1 at a predetermined angle with a predetermined angle with respect to the horizontal direction. A second electromagnetic coil 12b is wound with the same number of turns in a direction opposite to that of the coil 12a and inclined at the same angle. Therefore, the first coil 12a and the second coil 12b
Both coils 12a are wound around the outer periphery of the chamber 1, intersecting each other in a half-circle manner.

１２ｂの中心位置にルツボ４が置かれるようになってい
る。The crucible 4 is placed at the center of 12b.

このような構成にお−いて、第１図（ａ）に示されるよ
うに、第１及び第２のコイル１２ａ、１２ｂにそれぞれ
同じ大きさの励磁電流■　及び■。In such a configuration, as shown in FIG. 1(a), excitation currents (1) and (2) of the same magnitude are applied to the first and second coils 12a, 12b, respectively.

を流すと各コイル１２ａ、１２ｂによりルツボ４内には
同強度の磁界）−１，）−１ｂが発生し、この両磁界Ｈ
、Ｈの合成磁界として水平磁界Ｈｈがｂ 形成される。また、第１図（ｂ）に示されるように、例
えば第２のコイル１２ｂの励磁電流■ｂの　　　　　□
方向を反対方向へ切り換えると磁界Ｈ１の方向が１８０
°反転し、合成磁界として鉛直磁界Ｈが■ 形成される。このように、コイル１２ａ、１２ｂの励磁
電流１．Ｉｂの方向を切換えるだけで水平磁界Ｈｈと鉛
直磁界Ｈ７との切換えを簡単に行なうことができる。ま
た、現在のところ水平と鉛直の磁界しか利用されていな
いが、将来中間的な方向の磁界を利用したい場合が生じ
たとしても、励ｌｉ！１電流１．Ｉ、の大きさの比を変
えるだけで任意の方向の磁界を形成することができるの
で簡単に対応できる。When flowing, magnetic fields )-1, )-1b of the same strength are generated in the crucible 4 by the coils 12a and 12b, and both magnetic fields H
, H is formed as a horizontal magnetic field Hh. Moreover, as shown in FIG. 1(b), for example, the excitation current ■b of the second coil 12b □
When the direction is switched to the opposite direction, the direction of the magnetic field H1 becomes 180
° is reversed, and a vertical magnetic field H is formed as a composite magnetic field. In this way, the excitation current of the coils 12a and 12b is 1. Switching between the horizontal magnetic field Hh and the vertical magnetic field H7 can be easily performed by simply switching the direction of Ib. Also, although only horizontal and vertical magnetic fields are currently used, even if there is a case in the future where you would like to use magnetic fields in intermediate directions, excitation li! 1 current 1. A magnetic field in any direction can be created by simply changing the ratio of the magnitudes of I, so it can be easily handled.

第２図は従来装置による水平磁界と本実施例による水平
磁界とを示す図である。FIG. 2 is a diagram showing a horizontal magnetic field according to the conventional device and a horizontal magnetic field according to this embodiment.

同図（ａ）に示される従来装置の場合、鉄心３が無いと
して考えると、ルツボ４の位置（コイル２ａ、２ｂの中
点位置）に形成される水平磁界Ｈは次式で与えられる。In the case of the conventional device shown in FIG. 2A, assuming that there is no iron core 3, the horizontal magnetic field H formed at the position of the crucible 4 (midpoint position of the coils 2a and 2b) is given by the following equation.

但し、■　：コイル２ａ、２ｂの励磁電流Ｎ　：同　巻
　数 ｒ　：同　半　径 ２ｄ　：コイル２ａ、２ｂ間距離 一方、同図（ｂ）に示される本実施例の場合、コイル１
２ａ、１２ｂのアンペアターン数を上記従来例の場合と
同じにすれば、ルツボ４の位置（コイル１２ａ、１２ｂ
の中心位置）に各コイル１２ａ、１２ｂが形成する磁界
Ｈ，ｌ−１ｂは次式％式％ 但し、Ｒ：コイル１２ａ、１２ｂの半径従って、両磁界
ト１，１」ゎの合成磁界として形成される水平１ａ　！
Ｗ　Ｈｈは次式で与えられる。However, ■: Excitation current N of coils 2a and 2b: Same Number of turns r: Same Radius 2d: Distance between coils 2a and 2b On the other hand, in the case of this embodiment shown in the same figure (b), coil 1
If the number of ampere turns of coils 2a and 12b is the same as in the conventional example, the position of crucible 4 (coils 12a and 12b
The magnetic field H, l-1b formed by each coil 12a, 12b at the center position of Horizontal 1a to be done!
W Hh is given by the following formula.

Ｈｈ　　＝２　　ト１　　ａ　　　ｓ　ｉ　ｎ　　　θ
２１　　Ｎ５ｉｎ　　θ 但し、θ：水平方向に対するコイル１２ａ。Hh = 2 t1 a sin θ
21 N5in θ However, θ: Coil 12a in the horizontal direction.

１２ｂの傾斜角度 ここで、本実施例の外寸法を上記従来例とほぼ同じにす
るためにコイル１２ａ、１２ｂ間の鉛直方向の開きをコ
イル２ａ、２ｂの直径と等しい２ｒとし、水平方向の開
きをコイル２ａ、２ｂ間距殖と等しい２ｄとすると、 Ｒ＝２　（ｒ２　＋ｄ２）　１／２ となるから（２）式は次式のようになる。Inclination angle of 12bHere, in order to make the external dimensions of this embodiment almost the same as those of the conventional example, the vertical opening between the coils 12a and 12b is set to 2r, which is equal to the diameter of the coils 2a and 2b, and the horizontal opening is If 2d is equal to the distance multiplication between the coils 2a and 2b, then R=2 (r2 + d2) 1/2, so the equation (2) becomes the following equation.

実例として、 ２ｒ＝０．６ｍ ２ｄ＝１．　０ｍ の場合について磁界を求めてみると、従来装置による水
平磁界Ｈ及び本実施例による水平磁界Ｈｈは Ｈ＝０．　４５４　　ｌＮ １−１ｉ　＝０．８８　ＩＮ となる。即ち、 となり、両装置共アンペアターン数が同じで外寸法がほ
ぼ同じであれば本実施例の方が２倍近く強い磁界が１９
られることを示している。As an example: 2r=0.6m 2d=1. When calculating the magnetic field in the case of 0 m, the horizontal magnetic field H by the conventional device and the horizontal magnetic field Hh by this embodiment are H=0. 454 IN 1-1i =0.88 IN. In other words, if both devices have the same number of ampere turns and approximately the same external dimensions, the magnetic field of this example is nearly twice as strong as 19
This indicates that the

また、上記従来装置においてコイル２ａ、２ｂに鉄心を
挿入しチャンバ１の外側へ漏れていた磁束もチャンバ１
内へ導くようにすれば、概略的に言って磁界Ｈの強度を
２倍近くまで、つまり本実施例の磁界Ｈｈの強度近くま
で増加させることができるが、この場合には第３図を参
照して前述したように鉄心３の分だけ装置重量が１０倍
程度増加してしまうことになる。従って、本実施例なら
ば］イルのみで従来の鉄心を挿入した装置と同程度の磁
界強度が得られるので、コイル半径が従来装置よりも大
きいことを考慮しても、装置重量は従来装置よりも数分
の１以下に軽くなる。In addition, the magnetic flux that would have leaked to the outside of the chamber 1 by inserting the iron core into the coils 2a and 2b in the conventional device described above is also removed from the chamber 1.
If the magnetic field H is guided inward, the strength of the magnetic field H can be roughly doubled, that is, close to the strength of the magnetic field Hh of this embodiment. In this case, see FIG. 3. As mentioned above, the weight of the device increases by about 10 times due to the iron core 3. Therefore, in this example, it is possible to obtain a magnetic field strength comparable to that of a conventional device with an iron core inserted using just the coil, so even considering that the coil radius is larger than the conventional device, the device weighs less than the conventional device. It also becomes lighter than a fraction of the weight.

ところで、上記のように本実施例は従来装置に比べ大幅
に軽旦化できるという利点も有するものであるが、それ
でも３　ｋＧｓ　、４　ｋＧｓといった磁束密度を発生
させるためには従来装置と同様にかなり大きいコイル寸
法を要することになる。そこで、実用上はコイル１２ａ
、１２ｂを超電導コイルとすることが望ましい。By the way, as mentioned above, this embodiment has the advantage of being much lighter than the conventional device, but it still requires a considerable amount of energy to generate magnetic flux densities of 3 kGs and 4 kGs, just like the conventional device. This requires a large coil size. Therefore, in practice, the coil 12a
, 12b are preferably superconducting coils.

つまり、信頼性を保てる範囲内でコイルの銅線に流し得
る電流の大きさは、常電導風冷の場合で３Ａ／７程度、
また常電導水冷の場合でも５〜７Ａ／−程度である。し
かし、超電導の場合には１０、ＯＡ／−程度となるため
同じアンペアターンを得るために常電導よりも２０分の
１程度小さい断面積のコイルで済むことになる。このこ
とは、超電導コイルを極低温に保すためのクライオスタ
ットと呼ばれる特殊容器による寸法増加分（コイル１２
ａ、１２ｂの内外にそれぞれ’ｌ０ｃｍ程度）を加えて
も、はるかにコンパクトなコイル寸法となることを意味
している。In other words, the amount of current that can be passed through the copper wire of the coil within the range that can maintain reliability is approximately 3A/7 in the case of normal conductive air cooling.
Moreover, even in the case of normal conductive water cooling, it is about 5 to 7 A/-. However, in the case of superconducting, it is about 10.OA/-, so in order to obtain the same ampere turns, a coil with a cross-sectional area about one-twentieth smaller than that of normal conducting is sufficient. This is due to the increase in size (coil 12
This means that even if 10cm is added to the inside and outside of a and 12b, the coil dimensions will be much more compact.

更に、超電導コイルとすることにより励磁に要する電力
消費等のランニングコストを大幅に削減することができ
る。即ち、第３図（Ｃ）は鉄心を有する常電導コイルを
用いた従来装置において、２　ｋＧｓ　、３　ｋＧｓ及
び４　ｋＧｓの各磁束密度を得るためのコイルの励磁に
要する消費電力つまり励磁損を示した図であるが、例え
ばコイル間距離が９００＋＋ｍで３　ｋＧｓの磁束密度
を生じさせた場合励磁損は約１５０に−にも達する。本
実施例ではコイル半径が従来装置より大きい分だけコイ
ルの抵抗が大きくなることから更に励磁損は大きくなる
。Furthermore, by using a superconducting coil, running costs such as power consumption required for excitation can be significantly reduced. That is, Fig. 3(C) shows the power consumption, that is, the excitation loss, required for excitation of the coil to obtain magnetic flux densities of 2 kGs, 3 kGs, and 4 kGs in a conventional device using a normally conducting coil with an iron core. For example, when the distance between the coils is 900++ m and a magnetic flux density of 3 kGs is generated, the excitation loss reaches about 150 -. In this embodiment, the resistance of the coil increases as the coil radius is larger than that of the conventional device, so the excitation loss further increases.

ところが、超電導コイルを用いればコイルの抵抗はほぼ
０となるため励磁損はほとんど無く使用電力としては極
低温を保つための冷凍機のコンブレッザ用の数ｋＨのみ
で足り省エネルギー効果は極めて大きい。However, if a superconducting coil is used, the resistance of the coil becomes almost 0, so there is almost no excitation loss, and the power consumption is only a few kHz for the compressor of the refrigerator to maintain the extremely low temperature, so the energy saving effect is extremely large.

尚、上記実施例においては集中巻のコイルを２個用いて
いるが、その変形例として集中巻コイルを２個以上複数
設けたもの、或いは分布巻コイルとしたものが考えられ
る。実際のコイルの製作に当っては、分布巻とした方が
両コイルが交差する部分での処理が楽になるためより優
れている。In the above embodiment, two concentrated winding coils are used, but as a modification thereof, two or more concentrated winding coils or a distributed winding coil may be considered. When actually manufacturing a coil, distributed winding is better because it makes it easier to process the parts where both coils intersect.

〔発明の効果〕〔Effect of the invention〕

以上説明したように、本発明によれば、単結晶引上装置
の外周に第１及び第２の電磁コイルを相互にたすきがけ
状に巻いたことにより、従来２台の装置を用いて形成し
ていた水平磁界と鉛直磁界とを従来装置とさほど変わら
ない外寸法とはるかに軽い重量とを有する１台の装置で
実現することができるようになり、単結晶引上装置の操
作性を大幅に向上させることができるという効果が得ら
れる。As explained above, according to the present invention, the first and second electromagnetic coils are wound around the outer periphery of the single crystal pulling device in a cross-crossing manner. It is now possible to create horizontal and vertical magnetic fields using a single device that has the same external dimensions as conventional devices and is much lighter in weight, greatly improving the operability of the single crystal pulling device. The effect is that it can be improved.

□□

【図面の簡単な説明】[Brief explanation of the drawing]

第１図（ａ）及び（ｂ）は本発明に係る磁界印加装置の
構成並びに水平磁界及び鉛直磁界を発生させる作用をそ
れぞれ示す斜視図、第２図（ａ）及び（ｂ）は従来の磁
界印加装置により形成される磁界及び本実施例により形
成される磁界をそれぞれ示す断面図、第３図（ａ）、（
ｂ）及び（Ｃ）は従来装置における鉄心重量、コイルｍ
Ｍ１及び励磁損をコイル間距離との関係で磁束密度をパ
ラメータとしてそれぞれ示す図、第４図は従来装置の構
成を示す図である。 １・・・単結晶引上装置チャンバ、１２ａ・・・第１の
電磁コイル、１２ｂ・・・第２の電磁コイル。 出願人代理人　　佐　　藤　　−雄 色　Ｉ　閉 も　２　図 Ｃｏ１１間社に窪 Ｃ０１１間ｉａ汚α Ｃｏｔ　Ｉ間ｆＥ馳 ３３図FIGS. 1(a) and (b) are perspective views showing the configuration of the magnetic field applying device according to the present invention and the function of generating a horizontal magnetic field and a vertical magnetic field, respectively. FIGS. Cross-sectional views showing the magnetic field formed by the application device and the magnetic field formed by this example, respectively, Fig. 3(a), (
b) and (C) are the iron core weight and coil m in the conventional device.
A diagram showing M1 and excitation loss in relation to the distance between coils and using magnetic flux density as a parameter, and FIG. 4 is a diagram showing the configuration of a conventional device. DESCRIPTION OF SYMBOLS 1... Single crystal puller chamber, 12a... 1st electromagnetic coil, 12b... 2nd electromagnetic coil. Applicant's agent Sato - Osiro I closed 2 Figures Co11 and Kubo C011 ia dirt α Cot I fE has 33 Figures

Claims (1)

【特許請求の範囲】 １、電磁コイルにより単結晶引上装置に所定方向の磁界
を印加する装置において、前記引上装置の外周に前記所
定方向に対し傾斜して巻かれた１又は２以上の第１の電
磁コイルと、前記引上装置の外周に前記所定方向に対し
前記第１の電磁コイルとは反対方向へ傾斜して巻かれた
１又は２以上の第２の電磁コイルとを有することを特徴
とする単結晶引上用磁界印加装置。 ２、前記第１及び第２の電磁コイルを超電導コイルとし
たことを特徴とする特許請求の範囲第１項記載の単結晶
引上用磁界印加装置。[Claims] 1. In a device that applies a magnetic field in a predetermined direction to a single crystal pulling device using an electromagnetic coil, one or more coils are wound around the outer periphery of the pulling device at an angle with respect to the predetermined direction. It has a first electromagnetic coil and one or more second electromagnetic coils wound around the outer periphery of the pulling device so as to be inclined in a direction opposite to the first electromagnetic coil with respect to the predetermined direction. A magnetic field application device for single crystal pulling characterized by: 2. The magnetic field applying device for pulling a single crystal according to claim 1, wherein the first and second electromagnetic coils are superconducting coils.