JPS635360B2 - - Google Patents
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- Publication number
- JPS635360B2 JPS635360B2 JP54131316A JP13131679A JPS635360B2 JP S635360 B2 JPS635360 B2 JP S635360B2 JP 54131316 A JP54131316 A JP 54131316A JP 13131679 A JP13131679 A JP 13131679A JP S635360 B2 JPS635360 B2 JP S635360B2
- Authority
- JP
- Japan
- Prior art keywords
- crystal
- weight
- crystal diameter
- diameter
- single crystal
- 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.)
- Expired
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- 239000013078 crystal Substances 0.000 claims description 52
- 238000000034 method Methods 0.000 claims description 13
- 238000004033 diameter control Methods 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 4
- 230000007423 decrease Effects 0.000 claims 1
- 230000003247 decreasing effect Effects 0.000 claims 1
- 239000000155 melt Substances 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- PXXKQOPKNFECSZ-UHFFFAOYSA-N platinum rhodium Chemical compound [Rh].[Pt] PXXKQOPKNFECSZ-UHFFFAOYSA-N 0.000 description 2
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- 229910013641 LiNbO 3 Inorganic materials 0.000 description 1
- 229910000629 Rh alloy Inorganic materials 0.000 description 1
- 239000002178 crystalline material Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Landscapes
- Crystals, And After-Treatments Of Crystals (AREA)
Description
【発明の詳細な説明】
本発明はチヨコラルスキー法による単結晶育成
における単結晶の径制御方法に関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the diameter of a single crystal in single crystal growth using the Czyochoralski method.
酸化物単結晶であるLiTaO3、LiNbO3等はチ
ヨコラルスキー法により育成されている。すなわ
ち白金、白金ロジウム、又はイリジウムのルツボ
の中に入れられた結晶材料を加熱溶融したのち、
種結晶を融液に接触させて徐々に融液温度を下げ
ながら引上げることにより単結晶を育成する。チ
ヨコラルスキー法による単結晶育成において、結
晶径の制御は重要な問題である。 Oxide single crystals such as LiTaO 3 and LiNbO 3 are grown by the Czyochoralski method. That is, after heating and melting the crystal material placed in a crucible of platinum, platinum rhodium, or iridium,
A single crystal is grown by bringing a seed crystal into contact with the melt and pulling it up while gradually lowering the temperature of the melt. Controlling the crystal diameter is an important issue in single crystal growth using the Czyochoralski method.
育成中の結晶直径はたとえばシリコンなどで
は、光学的な方法（TVカメラ）を用いて直接検
出されている。しかしながら光学的な測定方法は
対象物以外からの反射光等によつて誤動作する可
能性が高いこと、高融点材料（LiTaO3、YAG
等）の結晶育成においては、ルツボ上部をカバー
して十分に保温する必要があり、また揮発性
（GaAs、GaP等）材料の結晶育成においては、
観察用のぞき窓が曇るため、前述の光学的検出法
は適用できない。このため一般には結晶もしくは
融液の重量を検出し、これが所要の形状に対応し
た重量プログラムに一致するように制御して一定
径の結晶を得る方法が多用されている。かく測定
された結晶重量により融液から育成する単結晶の
直径制御方法は、一般に結晶育成時間の経過に応
じて予め定められたプログラム信号と、前記結晶
重量の偏差に対して比例、微分などの演算を行つ
て得られた、制御信号の和によりルツボの加熱電
力を変化させることにより偏差を零にし、直径を
一定にするものである。したがつて前記プログラ
ム信号が理想的であるほど、高精度な直径制御が
できることになる。しかしながら、一般に同一育
成炉においても、プログラム信号は育成の度毎に
その値は多少異なること、保温耐火物やルツボの
劣化等により育成炉を新しく作り直した場合には
プログラム信号はまつたく変つてしまうこと等に
より前記制御信号だけでは結晶径を常に所定の精
度内に保つことが困難になる。またプログラム信
号を新たに設定しなおすためには、さらに数回の
育成が必要となり、結晶製造歩留が低下するとい
うことがあり、前記直径制御方法だけでは、高精
度、高歩留りで結晶育成を行うことができない欠
点があつた。 The diameter of a growing crystal, for example in silicon, is directly detected using an optical method (TV camera). However, optical measurement methods have a high possibility of malfunction due to reflected light from other than the target object, and high melting point materials (LiTaO 3 , YAG
When growing crystals of volatile materials (GaAs, GaP, etc.), it is necessary to cover the top of the crucible and keep it sufficiently warm.
The optical detection method described above cannot be applied because the viewing window becomes cloudy. For this reason, a commonly used method is to detect the weight of the crystal or melt and control the weight to match a weight program corresponding to the desired shape to obtain a crystal of a constant diameter. The method of controlling the diameter of a single crystal grown from a melt based on the crystal weight measured in this way generally involves using a predetermined program signal according to the lapse of crystal growth time, and a method that is proportional, differential, etc. to the deviation of the crystal weight. By changing the heating power of the crucible based on the sum of control signals obtained through calculation, the deviation is made zero and the diameter is kept constant. Therefore, the more ideal the program signal is, the more accurate the diameter control can be. However, in general, even in the same growth furnace, the value of the program signal differs each time it is grown, and if the growth furnace is rebuilt due to deterioration of the heat-retaining refractory or crucible, the program signal may change rapidly. For this reason, it becomes difficult to always maintain the crystal diameter within a predetermined accuracy using only the control signal. In addition, in order to newly set the program signal, it is necessary to grow the crystal several more times, which may reduce the crystal manufacturing yield. There was a drawback that I couldn't do it.
この発明は上記欠点に鑑みなされたもので、高
精度、高歩留りで結晶育成が可能な単結晶の直径
制御方法を提供するものである。 The present invention was made in view of the above-mentioned drawbacks, and it is an object of the present invention to provide a method for controlling the diameter of a single crystal, which enables crystal growth with high precision and high yield.
即ち、本発明の概要は、結晶材料を溶融したる
つぼから引上げられる単結晶の重量を引上げられ
るべき単結晶の所要の形状に対応した重量プログ
ラムに一致するように、あらかじめ定められたプ
ログラム信号と、結晶重量偏差に基ついて比例、
微分等の演算を行つて得られた制御信号と、前記
偏差に基づいて、プログラム信号の設定値を自動
的に補正する第２の制御信号により、ルツボの加
熱電力を変化させて、単結晶の直径を自動制御す
ることを特徴とするものである。 That is, the present invention provides a predetermined program signal such that the weight of a single crystal to be pulled from a crucible in which the crystalline material is melted corresponds to a weight program corresponding to the desired shape of the single crystal to be pulled; proportional to the crystal weight deviation,
The heating power of the crucible is changed using a control signal obtained by performing calculations such as differentiation, and a second control signal that automatically corrects the set value of the program signal based on the deviation. The feature is that the diameter is automatically controlled.
次に本発明方法の実施例を図面を参照して説明
する。第１図は本発明による直径制御機能を具備
した単結晶育成装置の一例である。図中、１はル
ツボ、２は融液、３は結晶、４は高周波コイル、
５は重量検出器、６は重量信号発生器、７は増幅
器、８は比例、微分制御回路、９はプログラム設
定値補正回路、１０はプログラム信号発生器、１
１は高周波出力調節器、１２は高周波発振機であ
る。ルツボ１内の融液２から引上げつつある結晶
３の重量を重量検出器５により測定し、基準重量
信号６との差を取り、第一の制御信号を得る。す
なわち重量検出器５と基準重量信号６および重量
偏差を求める手段により結晶系が徐々に太つてい
るか徐々に細つているかを検出する手段を構成す
る。前記第一の制御信号は増幅器７で増幅後、一
方は比例、微分制御回路８により第二の制御信号
となる。他方は結晶系が設定値より太いか細いか
を判定する手段およびプログラム信号の時間勾配
を補正する手段を備えたプログラム設定値補正回
路により、偏差に基づき、プログラム信号発生器
１０のmV信号の時間勾配を自動的に補正する。
第二の制御信号及び時間勾配制御信号は高周波出
力調節器１１へ接続されており、高周波発振機１
２により、高周波コイル４に供給する高周波電力
を制御するものである。 Next, embodiments of the method of the present invention will be described with reference to the drawings. FIG. 1 is an example of a single crystal growth apparatus equipped with a diameter control function according to the present invention. In the figure, 1 is a crucible, 2 is a melt, 3 is a crystal, 4 is a high frequency coil,
5 is a weight detector, 6 is a weight signal generator, 7 is an amplifier, 8 is a proportional and differential control circuit, 9 is a program setting value correction circuit, 10 is a program signal generator, 1
1 is a high frequency output regulator, and 12 is a high frequency oscillator. The weight of the crystal 3 being pulled from the melt 2 in the crucible 1 is measured by a weight detector 5, and the difference from the reference weight signal 6 is taken to obtain a first control signal. That is, the weight detector 5, the reference weight signal 6, and the means for determining weight deviation constitute a means for detecting whether the crystal system is gradually becoming thicker or thinner. After the first control signal is amplified by an amplifier 7, one becomes a second control signal by a proportional and differential control circuit 8. On the other hand, a program set value correction circuit having means for determining whether the crystal system is thicker or thinner than the set value and means for correcting the time gradient of the program signal adjusts the time gradient of the mV signal of the program signal generator 10 based on the deviation. automatically corrects.
The second control signal and the time gradient control signal are connected to the high frequency output regulator 11, and the high frequency oscillator 1
2 controls the high frequency power supplied to the high frequency coil 4.
第２図はプログラム設定値補正回路９の動作の
一例を示すものである。たとえば、あらかじめ定
めたプログラム信号が不適切な場合は第２図ａの
ような重量偏差が生じる。線ａは、結晶径が設定
値よりも徐々に太くなつていることを示してい
る。この偏差信号により第２図ｂの線ａのような
プログラム信号になるように、プログラム信号発
生器１０へ出力するものである。線ｃはあらかじ
め定めたプログラム信号であり、また結晶径が設
定値よりも徐々に細つていく場合は第２図ａ，ｂ
の線ｂのような信号となる。 FIG. 2 shows an example of the operation of the program setting value correction circuit 9. For example, if a predetermined program signal is inappropriate, a weight deviation as shown in FIG. 2a will occur. Line a indicates that the crystal diameter gradually becomes thicker than the set value. This deviation signal is outputted to the program signal generator 10 so as to produce a program signal as shown by line a in FIG. 2b. Line c is a predetermined program signal, and if the crystal diameter gradually becomes smaller than the set value, the lines a and b in Figure 2
The signal will be as shown in line b.
次に具体的な例として表面波用圧電基板材料で
あるLiTaO3単結晶を育成する場合について説明
する。白金―ロジウム合金製のルツボ１（〜100
mmφ×100mmｈ×２mmｔ）にLi2CO3とTa2O5の粉
末を所定の混合比になるように入れ、〜1650℃ま
で加熱溶融した。次に種結晶を融液に接触させた
のちプログラム信号の設定値を1.4μV／minとし
て、温度を降下させ、結晶肩部を育成した。結晶
径が、65mmφになつたところで、前記設定値を
0.7μV／minとして、比例微分制御回路８を作動
させ、胴体部の育成を行つたところ、重量偏差は
第２図ａの線ａのようになり、最大で約2mVの
振れが生じ、育成後の結晶径変動は＋2.5％であ
つた。次にプログラム信号設定値は同じとし、プ
ログラム設定値補正回路９を作動させて同様に育
成を行つたところ、重量偏差は、0.5mV以下であ
り、育成後の結晶径変動は＋１％以内にすること
が出来た。また育成中の高周波電力の記録から、
最適なプログラム設定値は、〜0.63μV／minとす
れば良い育成結果が得られることが分つた。 Next, as a specific example, a case will be described in which a LiTaO 3 single crystal, which is a piezoelectric substrate material for surface waves, is grown. Crucible 1 made of platinum-rhodium alloy (~100
Powders of Li 2 CO 3 and Ta 2 O 5 were put into a tube (mmφ×100 mmh×2 mmt) at a predetermined mixing ratio and heated and melted to ~1650°C. Next, after bringing the seed crystal into contact with the melt, the temperature was lowered by setting the program signal to 1.4 μV/min to grow a crystal shoulder. When the crystal diameter reaches 65mmφ, change the above setting value.
When the proportional differential control circuit 8 was operated at 0.7μV/min and the body was grown, the weight deviation was as shown in line a in Figure 2a, with a maximum deviation of about 2mV, and after the growth. The crystal diameter variation was +2.5%. Next, when the program signal setting values were kept the same and the program setting value correction circuit 9 was activated to perform the same growth, the weight deviation was less than 0.5 mV, and the crystal diameter fluctuation after growth was within +1%. I was able to do it. Also, from the records of high frequency power during cultivation,
It was found that good growth results could be obtained by setting the optimal program setting value to ~0.63μV/min.
以上のべた機能を具備した結晶育成装置によれ
ば、耐火物やルツボの劣化等により、育成条件が
大幅に変化しても、極めて良好な直径制御が出来
ることが分つた。 It has been found that the crystal growth apparatus equipped with the above-mentioned functions allows extremely good diameter control even if the growth conditions change significantly due to deterioration of the refractory or crucible.
さらに第３図は本発明の機能をコンピユーター
で実行するようにした場合の一実施例であり、図
中１３は、Ａ―Ｄ変換器、１４はコンピユーター
システム、１５はＤ―Ａ変換器である。 Further, FIG. 3 shows an embodiment in which the functions of the present invention are executed by a computer, and in the figure, 13 is an AD converter, 14 is a computer system, and 15 is a DA converter. .
このようにコンピユーターの融通性、万能性を
有効に利用すれば、プログラム信号発生器１０や
比例微分制御回路の機能も同様に実行することも
可能である。 By effectively utilizing the flexibility and versatility of the computer in this way, it is also possible to perform the functions of the program signal generator 10 and the proportional differential control circuit in the same way.
このようにして、育成した結晶は従来の方法に
よるものに較べて何ら孫色のないものである。 The crystals grown in this manner have no grander color than those produced by conventional methods.
以上の様に本発明によれば、
(1)良好な結晶径制御ができる。(2)保温耐火物や
ルツボの劣化等による育成条件の変動の影響が少
い。(3)手動によりプログラム信号を最適化する必
要がないため、プログラム信号を作製する時間が
従来の方法に較べて〜1/3に短縮できる。(4)結晶
作製歩留りが、従来の方法に較べて〜10％良いた
め工業的に適用することにより生産性が向上す
る。等の効果が得られた。 As described above, according to the present invention, (1) excellent crystal diameter control is possible; (2) It is less affected by changes in growth conditions due to deterioration of heat-retaining refractories and crucibles. (3) Since there is no need to manually optimize the program signal, the time required to create the program signal can be reduced to ~1/3 compared to conventional methods. (4) Since the crystal production yield is ~10% higher than that of conventional methods, productivity can be improved by industrial application. The following effects were obtained.
第１図は本発明の実施例を説明するための構成
図、第２図はプログラム設定値補正回路の動作を
説明するための図、第３図は本発明の他の実施例
を説明するための構成図である。
１……ルツボ、２……融液、３……結晶、４…
…高周波コイル、５……重量検出器、６……重量
信号発生器、７……増幅器、８……比例微分制御
回路、９……プログラム設定値補正回路、１０…
…プログラム信号発生器、１１……高周波出力調
節器、１２……高周波発振機、１３……Ａ―Ｄ変
換器、１４……コンピユーターシステム、１５…
…Ｄ―Ａ変換器。
FIG. 1 is a block diagram for explaining an embodiment of the present invention, FIG. 2 is a diagram for explaining the operation of the program setting value correction circuit, and FIG. 3 is a diagram for explaining another embodiment of the present invention. FIG. 1... Crucible, 2... Melt, 3... Crystal, 4...
...High frequency coil, 5...Weight detector, 6...Weight signal generator, 7...Amplifier, 8...Proportional differential control circuit, 9...Program setting value correction circuit, 10...
...Program signal generator, 11...High frequency output regulator, 12...High frequency oscillator, 13...A-D converter, 14...Computer system, 15...
...D-A converter.
Claims (1)
単結晶の重量を、引上げられるべき単結晶の所要
の形状に対応した重量プログラムに一致するよう
に、あらかじめ定められたプログラム信号と重量
偏差に基づき帰還制御する制御信号により、ルツ
ボ加熱電力を変化させて結晶径制御を行なう単結
晶の直径制御方法であつて、少なくとも下記(a)〜
(c)の手段を具備し、結晶径が設定値より太くかつ
徐々に太つている時又は結晶径が設定値より細く
かつ徐々に細つている時に補正回路によりプログ
ラム信号発生器の時間勾配を前記重量偏差に基づ
いて自動的に補正することを特徴とする単結晶の
直径制御方法。 (a) 結晶径が徐々に太つているか徐々に細つてい
るかを検知する手段 (b) 結晶径が設定値より太いか細いかを判定する
手段 (c) プログラム信号の時間勾配を補正する手段。[Claims] 1. A predetermined program signal and weight so that the weight of a single crystal to be pulled from a crucible in which crystal material is melted matches a weight program corresponding to a desired shape of the single crystal to be pulled. A single crystal diameter control method that controls the crystal diameter by changing the crucible heating power using a control signal that performs feedback control based on the deviation, the method comprising at least the following (a) to
(c), when the crystal diameter is larger than the set value and gradually increases, or when the crystal diameter is smaller than the set value and gradually decreases, the correction circuit adjusts the time gradient of the program signal generator to the above value. A single crystal diameter control method characterized by automatic correction based on weight deviation. (a) Means for detecting whether the crystal diameter is gradually increasing or decreasing; (b) Means for determining whether the crystal diameter is thicker or thinner than a set value; (c) Means for correcting the time gradient of the program signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13131679A JPS5659692A (en) | 1979-10-13 | 1979-10-13 | Diameter controlling method for single crystal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13131679A JPS5659692A (en) | 1979-10-13 | 1979-10-13 | Diameter controlling method for single crystal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5659692A JPS5659692A (en) | 1981-05-23 |
| JPS635360B2 true JPS635360B2 (en) | 1988-02-03 |
Family
ID=15055095
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13131679A Granted JPS5659692A (en) | 1979-10-13 | 1979-10-13 | Diameter controlling method for single crystal |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5659692A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6011297A (en) * | 1983-06-27 | 1985-01-21 | Nippon Telegr & Teleph Corp <Ntt> | Method and device for controlling growth of crystal |
| JPS6065788A (en) * | 1983-09-21 | 1985-04-15 | Sumitomo Metal Mining Co Ltd | Production of single crystal |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4846757A (en) * | 1971-10-18 | 1973-07-03 | ||
| JPS4989686A (en) * | 1972-12-27 | 1974-08-27 | ||
| JPS50131683A (en) * | 1974-04-03 | 1975-10-17 | ||
| JPS5135678A (en) * | 1974-09-20 | 1976-03-26 | Okura Denki Co Ltd | JURYOHOCHOKUKEISEIGYOHOHO |
| JPS51126853A (en) * | 1975-04-28 | 1976-11-05 | B Ii Ii:Kk | A diameter deviation detecting method at a crystal hoister |
-
1979
- 1979-10-13 JP JP13131679A patent/JPS5659692A/en active Granted
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4846757A (en) * | 1971-10-18 | 1973-07-03 | ||
| JPS4989686A (en) * | 1972-12-27 | 1974-08-27 | ||
| JPS50131683A (en) * | 1974-04-03 | 1975-10-17 | ||
| JPS5135678A (en) * | 1974-09-20 | 1976-03-26 | Okura Denki Co Ltd | JURYOHOCHOKUKEISEIGYOHOHO |
| JPS51126853A (en) * | 1975-04-28 | 1976-11-05 | B Ii Ii:Kk | A diameter deviation detecting method at a crystal hoister |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5659692A (en) | 1981-05-23 |
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