JPH02279585A - Method for detecting temperature of melt in czochralski method - Google Patents
Method for detecting temperature of melt in czochralski methodInfo
- Publication number
- JPH02279585A JPH02279585A JP10092889A JP10092889A JPH02279585A JP H02279585 A JPH02279585 A JP H02279585A JP 10092889 A JP10092889 A JP 10092889A JP 10092889 A JP10092889 A JP 10092889A JP H02279585 A JPH02279585 A JP H02279585A
- Authority
- JP
- Japan
- Prior art keywords
- melt
- fluctuation
- temperature
- amplitude
- light
- 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.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims description 28
- 239000000155 melt Substances 0.000 claims abstract description 53
- 230000003287 optical effect Effects 0.000 claims abstract 3
- 238000001514 detection method Methods 0.000 claims 2
- 239000013078 crystal Substances 0.000 abstract description 17
- 230000010355 oscillation Effects 0.000 abstract 1
- 238000009529 body temperature measurement Methods 0.000 description 11
- 238000005259 measurement Methods 0.000 description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- 239000010703 silicon Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000005855 radiation Effects 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
Landscapes
- Crystals, And After-Treatments Of Crystals (AREA)
- Liquid Deposition Of Substances Of Which Semiconductor Devices Are Composed (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、るつぼ中の融液を凝固させながら上方へ引上
げて単結晶ブロックを得るＣＺ法（チヨクラスキー法）
に係り、特にその融液温度検出法に関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention is a CZ method (Cyochlaski method) in which a single crystal block is obtained by pulling a melt in a crucible upward while solidifying it.
In particular, the present invention relates to a method for detecting the temperature of the melt.
ＩＣ，ＬＳＩ等の製造に使用されるシリコン等の単結晶
ブロックの製造方法として、ＣＺ法がよく知られている
。この方法は、第１図に示すように、回転するるつぼｌ
に収容したシリコン等の融液２を、るつぼ１に対して相
対的に回転させながらワイヤ３により引上げ、凝固させ
て柱状の単結晶ブロック４を製造するものである。るつ
ぼ１は外周側から電熱ヒーター１６によって加熱されて
いる。The CZ method is well known as a method for manufacturing single crystal blocks of silicon or the like used in the manufacture of ICs, LSIs, and the like. This method uses a rotating crucible as shown in Figure 1.
A melt 2 of silicon or the like contained in the crucible is pulled up by a wire 3 while being rotated relative to the crucible 1 and solidified to produce a columnar single crystal block 4. The crucible 1 is heated from the outer circumferential side by an electric heater 16.
ＣＺ法で均一な単結晶組織の製品を得るためには融液温
度を管理することが重要であり、そのためには融液温度
を正確に測定することが必要になる。ＣＺ法における融
液温度測定法には、従来より放射温度計や熱電対が使わ
れている。放射温度計では融液表面からの放射熱を覗き
窓５を通して測定することにより測温が行われる。熱電
対で融液中に直接浸漬されて測温が行われる。In order to obtain a product with a uniform single crystal structure using the CZ method, it is important to control the melt temperature, and for this purpose it is necessary to accurately measure the melt temperature. Conventionally, radiation thermometers and thermocouples have been used to measure melt temperature in the CZ method. The radiation thermometer measures temperature by measuring radiant heat from the surface of the melt through a viewing window 5. Temperature measurement is performed with a thermocouple that is immersed directly into the melt.
このような従来の融液温度測定法のうち、放射温度針に
よる方法では、融液が高温であるため、その表面が鏡面
状態でかつ波立ち状態になっており、そのため測定点周
囲からの放射熱が測定されてしまい、正確な温度を測定
できない問題がある。Among these conventional melt temperature measurement methods, in the method using a radiation temperature needle, the surface of the melt is mirror-like and undulating because the temperature of the melt is high. There is a problem that the temperature cannot be measured accurately.
また、覗き窓５の汚れにより検出光量が減衰し、これも
測定精度を低下させる原因になっている。Furthermore, the amount of detected light is attenuated due to dirt on the viewing window 5, which also causes a decrease in measurement accuracy.
熱電対による温度測定では、熱電対を保護管に収容した
状態で測温が行われるが、それでも短時間しか浸漬でき
ず、連続測温は不可能である。In temperature measurement using a thermocouple, the temperature is measured with the thermocouple housed in a protective tube, but even then, it can only be immersed for a short time and continuous temperature measurement is not possible.
本発明は、上記従来の温度測定法における諸問題を解決
した高精度で連続測定が可能な融液温度測定法を提供す
ることを目的とする。SUMMARY OF THE INVENTION An object of the present invention is to provide a melt temperature measurement method that solves the problems of the conventional temperature measurement methods and allows continuous measurement with high accuracy.
（課題を解決するための手段〕
本発明は、融液表面のゆらぎ現象が融液温度と関係する
こ々を利用するものである。すなわち、ゆらぎの振幅お
よびＩｉＩＭは融液の粘度と関係し、融液の粘度は融液
の温度と関係し、その結果としてゆらぎの振幅および周
期は融液温度と関係する、第３図（イ）に、溶融状態の
シリコンについてその温度と粘度の関係を示す。(Means for Solving the Problems) The present invention utilizes the fact that the fluctuation phenomenon of the melt surface is related to the melt temperature. That is, the amplitude of the fluctuation and IiIM are related to the viscosity of the melt. , the viscosity of the melt is related to the temperature of the melt, and as a result, the amplitude and period of fluctuation are related to the temperature of the melt. Figure 3 (a) shows the relationship between temperature and viscosity for silicon in the molten state. show.
同図にＡ曲線で示されるように、シリコン融液の温度が
上昇すればその粘度が下がる。また、融液面に波立ち、
すなわちゆらぎが生じた場合、そのゆらぎ強度は振幅ａ
と周波数ｆの積（ａ−ｆ）の関数α（ａ−ｆ）として示
される。ゆらぎ強度α（ａ−ｆ）と（ａ−ｆ）との関係
は第３図（ロ）の通りである。As shown by curve A in the figure, as the temperature of the silicon melt increases, its viscosity decreases. In addition, ripples appear on the melt surface,
In other words, when fluctuation occurs, the fluctuation strength is equal to the amplitude a
It is expressed as a function α(a-f) of the product (a-f) of and frequency f. The relationship between the fluctuation intensities α(a-f) and (a-f) is shown in FIG. 3(b).
本発明者らの実験によれば、ゆらぎ強度と粘度とは反比
例のＮｌ係にあり、それ故、ゆらぎ強度α（ａ・ｆ）は
、第３図ｆイ）に８曲線で示されるごとく、温度の上昇
と共に上昇する。Ｃ２法ではその引上げ中継液面が可避
的にゆらぎ、しかも、ゆらぎを発生させる振動条件（炉
内圧力、融液表面のキャリアガス流速等）は通常は一定
である。したがって、融液のゆらぎ強度α（ａ−ｆ）を
検出すれば、融液の温度が正確に測定される。According to the experiments conducted by the present inventors, the fluctuation strength and viscosity are inversely proportional to Nl, and therefore, the fluctuation strength α(a・f) is as shown by the 8 curves in Figure 3 f). It increases with increasing temperature. In the C2 method, the pulling relay liquid level inevitably fluctuates, and the vibration conditions that cause the fluctuations (furnace pressure, carrier gas flow rate on the melt surface, etc.) are usually constant. Therefore, by detecting the fluctuation strength α(a-f) of the melt, the temperature of the melt can be accurately measured.
本発明の温度測定法は、このような事実関係およびゆら
ぎを発生させる振動条件が一定であることを利用して開
発されたもので、融液面のゆらぎ振幅およびゆらぎ周波
数から求めたゆらぎ強度に基づいて融液温度を算出する
ことを特徴としてなる。The temperature measurement method of the present invention was developed by taking advantage of this factual relationship and the fact that the vibration conditions that generate fluctuations are constant. The feature is that the melt temperature is calculated based on the temperature of the melt.
第４図は本発明の一実施態様を示している。融液２の表
面に入射された光線９は融液２の表面で反射され、その
表面のゆらぎにともなって反射光７は振動する０本発明
では、融液２面に光源６より入射された光線９の反射光
７について、その先軸の変動振幅および振動周波数を測
定し、両者の積よりゆらぎ強度を算出し、算出されたゆ
らぎ強度より融液温度を算出する。FIG. 4 shows one embodiment of the invention. The light beam 9 incident on the surface of the melt 2 is reflected by the surface of the melt 2, and the reflected light 7 oscillates as the surface fluctuates. Regarding the reflected light 7 of the light beam 9, the fluctuation amplitude and vibration frequency of the leading axis are measured, the fluctuation strength is calculated from the product of the two, and the melt temperature is calculated from the calculated fluctuation strength.
測定精度をさらに高めるためには、例えば入射光線９と
してレーザ光を使い、その反射光を二次元ＰＳＤカメラ
で受像し、該カメラより出力される受像光軌跡の電気信
号よりその振幅と周波数を測定し、両者を電気的に処理
して融液温度を算出する方法がとられる。In order to further improve measurement accuracy, for example, a laser beam can be used as the incident light beam 9, the reflected light is imaged by a two-dimensional PSD camera, and its amplitude and frequency are measured from the electric signal of the received light trajectory output from the camera. However, a method is used in which both are processed electrically to calculate the melt temperature.
本発明の温度測定法によるときは、融液面のゆらぎ振幅
およびゆらぎ周期から融液温度が測定されるので、従来
法で問題となる間接放射熱等の誤差要因が排除され、ま
た完全な間接測定であるので長時間の連続測定が可能に
なる。したがって、融液温度が精度よく連続的に測定さ
れる。When using the temperature measurement method of the present invention, the melt temperature is measured from the fluctuation amplitude and fluctuation period of the melt surface, so error factors such as indirect radiant heat that are problematic with conventional methods are eliminated, and complete indirect Since it is a measurement, continuous measurement for a long time is possible. Therefore, the melt temperature is continuously measured with high accuracy.
以下に本発明をその実施例について説明する。 The present invention will be described below with reference to its embodiments.
第２図（イ）および（ロ）は本発明の実施態梯をさらに
具体的に示した平面図および縦断面図である。FIGS. 2(A) and 2(B) are a plan view and a vertical cross-sectional view showing a ladder according to an embodiment of the present invention in more detail.
レーザ光源ｌＯから照射されたレーザ光束は仕切窓ｌｌ
を通して融液２面に入射する。融液２面で反射した光束
は覗き窓５を通してスクリーン１２に光点として表われ
る。融液２面のゆらぎの振幅および周期に対応してスク
リーン１２上の光点は特定の軌跡を画いて周期移動する
。スクリーン１２上の光点の軌跡は二次元ＰＳＤカメラ
８により１影されて、カメラ演算部１８でＸ軸成分、Ｙ
軸成分の２種類のアナログ電気信号に変換される。The laser beam irradiated from the laser light source lO passes through the partition window l
The melt enters the two surfaces through the The luminous flux reflected by the two surfaces of the melt passes through the viewing window 5 and appears on the screen 12 as a light spot. A light spot on the screen 12 periodically moves along a specific locus in accordance with the amplitude and period of fluctuations on the two surfaces of the melt. The trajectory of the light spot on the screen 12 is shadowed by the two-dimensional PSD camera 8, and the camera calculation unit 18 calculates the X-axis component and the Y-axis component.
The axial components are converted into two types of analog electrical signals.
２種頬のアナログ信号は、第５図に示すように、ＲＡＭ
、ＲＯＭ （記憶素子）およびＡ／Ｄ （アナログ、デ
ジタル変換器）を有する中央演算装置ＣＰＵによるコン
ピューターシステム１３に取り込まれる。所定時間内の
軌跡の記録からＸ軸、Ｙ軸の各々について振幅ａ、周波
数ｆがコンピューターシステム１３によって求められ、
これを、予め実験的に求めた（ａ−ｆ）とゆらぎ強度α
（ａ・ｒ）との関係に照合することにより、ゆらぎ強度
α（ａ−ｆ）が求められる。The analog signal for the second cheek is stored in the RAM as shown in Figure 5.
, ROM (memory element) and A/D (analog to digital converter) into a computer system 13 with a central processing unit CPU. The computer system 13 calculates the amplitude a and the frequency f for each of the X-axis and Y-axis from the record of the trajectory within a predetermined time,
This is determined experimentally in advance (a-f) and the fluctuation strength α
By comparing the relationship with (a·r), the fluctuation strength α(a−f) is determined.
ゆらぎ強度α（ａ−１）と融液温度との関係は予め実験
により求められていて、そのデータがパーソナルコンピ
ューターシステム１４に記憶されている。コンピュータ
システム１３より出力されたゆらぎ強度α（ａ−ｆ）は
パーソナルコンピューター１４に入力され、ここで上記
記憶データと対比されて融液温度が求められる。求めら
れた温度は表示器１５に表示される。The relationship between the fluctuation intensity α(a-1) and the melt temperature is determined in advance through experiments, and the data is stored in the personal computer system 14. The fluctuation intensity α(a-f) output from the computer system 13 is input to the personal computer 14, where it is compared with the above-mentioned stored data to determine the melt temperature. The determined temperature is displayed on the display 15.
本発明の温度測定法を利用すれば、ＣＺ法の単結晶引上
げ過程、すなわち種結晶より単結晶を成長させながら上
方へ引上げ、最後に結晶径を漸次減少させるテール絞り
までの間、放射熱等の影響を受けることなく連続して精
度よく融液温度が測定される。そして、その温度値に基
づいて引上温度、すなわちるつぼ周囲に設けられたヒー
ター４の出力を制御することにより、融液温度を単結晶
製造における最適値に保持することができる。If the temperature measurement method of the present invention is used, radiant heat, etc. can be used during the single crystal pulling process of the CZ method, that is, the single crystal is pulled upward while growing from the seed crystal, and finally the tail drawing in which the crystal diameter is gradually reduced. Melt temperature can be measured continuously and accurately without being affected by Then, by controlling the pulling temperature, that is, the output of the heater 4 provided around the crucible, based on the temperature value, the melt temperature can be maintained at the optimum value for single crystal production.
こうして融液温度を最適値に管理することにより、次の
効果を得た。By controlling the melt temperature to an optimum value in this way, the following effects were obtained.
■ 単結晶の無転位（Ｄｉｓｌｏｃａｔｉｏｎ Ｆｒｅ
ｅ）の比率（ＤＦ率）を５０％から８０％に向上させる
ことができた。■ Single crystal dislocation free
The ratio e) (DF rate) could be improved from 50% to 80%.
■ 単結晶の直径変動を±１．０−から１０．５ｍｍに
減少させることができた。(2) It was possible to reduce the variation in diameter of a single crystal from ±1.0 to 10.5 mm.
■ 成長した単結晶内に取込まれる酸素濃度Ｏ１のばら
つきを±０．５Ｘ１０”原子／ ｃ ｃから±０．２Ｘ
１７Ｉｆｆ原子／ ＣＣに減少させることができた。■ Variation in oxygen concentration O1 incorporated into the grown single crystal ±0.5X10” atoms/cc ±0.2X from c
It was possible to reduce it to 17 Iff atoms/CC.
■ 単結晶の引上げ所要時間を従来より２０％短縮させ
ることができた。■ The time required to pull a single crystal was reduced by 20% compared to conventional methods.
本発明の融液温度測定法は、融液面のゆらぎ振幅および
ゆらぎ周期に基づいて融液温度を間接測定するので、連
続測定が可能なことは勿論、ゆらぎを発生させる振動条
件が一定である限りは、外乱を受けることなく高精度な
温度測定を可能にする。その結果、ＣＺ法による単結晶
引上げ作業が高精度に管理され、単結晶ブロックの品質
が著しく向上する。The melt temperature measurement method of the present invention indirectly measures the melt temperature based on the fluctuation amplitude and fluctuation period of the melt surface, so it is possible to perform continuous measurement, and the vibration conditions that generate fluctuations are constant. As long as it allows for highly accurate temperature measurement without being subjected to disturbances. As a result, the single crystal pulling operation by the CZ method is managed with high precision, and the quality of the single crystal block is significantly improved.
第１図はＣＺ法を模式的に示した斜視図、第２図（イ）
および（ロ）は本発明を実施するための装置構成を示す
平面図および縦断面図、第３図（イｊは粘度およびゆら
ぎ強度に対する融液温度の影響度を示す線図、第３図（
ロ）はゆらぎ強度と振幅Ｘ周期との関係を示す線図、第
４図および第５図は本発明の実施態様を示す模式図、第
５図は第２図の装置で用いられている信号処理回路のブ
ロック線図である。
１；るつぼ、２：融液、３；ワイヤ、４：単結晶ブロッ
ク、５：覗き窓、６：光源、７二反射光、８：二次元Ｐ
ＳＤカメラ、９：入射光、１０：レーザ光源、１２ニス
クリーン、１３：コンピューターシステム。
出 願 人
大阪チタニウム製造株式会社
第
図
第
図Figure 1 is a perspective view schematically showing the CZ method, Figure 2 (a)
and (b) are a plan view and a longitudinal cross-sectional view showing the configuration of an apparatus for carrying out the present invention, and FIG.
b) is a diagram showing the relationship between fluctuation intensity and amplitude X period; FIGS. 4 and 5 are schematic diagrams showing embodiments of the present invention; FIG. FIG. 2 is a block diagram of a processing circuit. 1: Crucible, 2: Melt, 3: Wire, 4: Single crystal block, 5: Peephole, 6: Light source, 7 Two reflected light, 8: Two-dimensional P
SD camera, 9: incident light, 10: laser light source, 12 screen, 13: computer system. Applicant Osaka Titanium Manufacturing Co., Ltd.
Claims (1)
ゆらぎ強度に基づいて融液温度を算出することを特徴と
するＣＺ法における融液温度の検出法。 ２、融液面のゆらぎ振幅およびゆらぎ周波数を融液面か
らの反射光の光路変動から測定することを特徴とする請
求項１に記載のＣＺ法における融液温度検出法。 ３、融液面のゆらぎ振幅およびゆらぎ周波数を融液面に
照射したレーザ光の反射光の光路変動から測定すること
を特徴とする請求項１または２に記載のＣＺ法における
融液温度検出法。[Scope of Claims] 1. A method for detecting melt temperature in the CZ method, characterized in that the melt temperature is calculated based on the fluctuation intensity obtained from the fluctuation amplitude and fluctuation frequency of the melt surface. 2. The melt temperature detection method in the CZ method according to claim 1, wherein the fluctuation amplitude and fluctuation frequency of the melt surface are measured from optical path fluctuations of reflected light from the melt surface. 3. The melt temperature detection method in the CZ method according to claim 1 or 2, characterized in that the fluctuation amplitude and fluctuation frequency of the melt surface are measured from optical path fluctuations of reflected light of a laser beam irradiated to the melt surface. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10092889A JPH02279585A (en) | 1989-04-20 | 1989-04-20 | Method for detecting temperature of melt in czochralski method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10092889A JPH02279585A (en) | 1989-04-20 | 1989-04-20 | Method for detecting temperature of melt in czochralski method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02279585A true JPH02279585A (en) | 1990-11-15 |
Family
ID=14287015
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10092889A Pending JPH02279585A (en) | 1989-04-20 | 1989-04-20 | Method for detecting temperature of melt in czochralski method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02279585A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0692784A (en) * | 1991-04-30 | 1994-04-05 | Mitsubishi Materials Corp | Liquid level control method |
-
1989
- 1989-04-20 JP JP10092889A patent/JPH02279585A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0692784A (en) * | 1991-04-30 | 1994-04-05 | Mitsubishi Materials Corp | Liquid level control method |
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