JPH02102187A - Measurement of height of melt level in cz method - Google Patents
Measurement of height of melt level in cz methodInfo
- Publication number
- JPH02102187A JPH02102187A JP25793988A JP25793988A JPH02102187A JP H02102187 A JPH02102187 A JP H02102187A JP 25793988 A JP25793988 A JP 25793988A JP 25793988 A JP25793988 A JP 25793988A JP H02102187 A JPH02102187 A JP H02102187A
- Authority
- JP
- Japan
- Prior art keywords
- fusion ring
- melt
- height
- measured
- melt level
- 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
- 238000005259 measurement Methods 0.000 title claims abstract description 9
- 238000000034 method Methods 0.000 title claims description 18
- 230000004927 fusion Effects 0.000 claims abstract description 35
- 239000013078 crystal Substances 0.000 claims abstract description 19
- 239000000155 melt Substances 0.000 claims description 29
- 230000003287 optical effect Effects 0.000 abstract description 15
- 229910052710 silicon Inorganic materials 0.000 abstract description 5
- 239000010703 silicon Substances 0.000 abstract description 5
- 239000007788 liquid Substances 0.000 description 23
- 238000010586 diagram Methods 0.000 description 8
- 238000001514 detection method Methods 0.000 description 7
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 230000005499 meniscus Effects 0.000 description 1
- 238000005375 photometry Methods 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 230000000007 visual effect Effects 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〕
この発明はＣＺ法（チックラスキー法）により単結晶を
るつぼから引上げる際の融液面高さの計測法に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for measuring the height of a melt surface when a single crystal is pulled from a crucible by the CZ method (Chicklasky method).
ＩＣ，ＬＳＩ等の製造に使用されるシリコン等の単結晶
の製造方法として、Ｃ７法がよく知られている。この方
法は、第１図の模式図に示すように、回転するるつぼｌ
に収容したシリコン等の結晶融液２を、ワイヤ３により
るつぼｌに対して回転させながら引上げ凝固させて、柱
状の単結晶４を製造するものである。るつぼｌは外周側
から電熱ヒータ１２により加熱される。The C7 method is well known as a method for manufacturing single crystals such as silicon used in manufacturing ICs, LSIs, and the like. This method uses a rotating crucible as shown in the schematic diagram of Figure 1.
A crystal melt 2 of silicon or the like contained in a crucible is pulled up and solidified while being rotated with respect to a crucible 1 by a wire 3, thereby producing a columnar single crystal 4. The crucible 1 is heated from the outer circumferential side by an electric heater 12.
引き上げ中の単結晶４の成長部、すなわち凝固部と結晶
融液２との境界には、メニスカスによる曲率の差が生じ
、見かけの輻射率を変えることによりいわゆるフュージ
ョンリング５が発現する。A difference in curvature due to the meniscus occurs at the boundary between the growing part of the single crystal 4 being pulled, that is, the solidified part, and the crystal melt 2, and by changing the apparent emissivity, a so-called fusion ring 5 appears.
このフュージョンリング５は、斜め上方の光学的手段８
からチャンバー６に設けられる測定窓７を通じて観察す
ることにより半楕円形状に捉えられる。This fusion ring 5 has an optical means 8 located diagonally above.
By observing through the measurement window 7 provided in the chamber 6, the shape is captured as a semi-ellipse.
ところで、このようなＣＺ法においては、融液２の液面
高さが単結晶４の引上速度を管理する上からきわめて大
切な要因である。融液の液面計としてはレーザーを利用
し、液面におけるレーザー反射を三角測量法にて測定す
る第７図のごとき液面計が文献等で紹介されている。By the way, in such a CZ method, the liquid level height of the melt 2 is an extremely important factor in controlling the pulling speed of the single crystal 4. As a melt level gauge, a liquid level gauge as shown in Fig. 7, which uses a laser and measures the laser reflection on the liquid surface by triangulation, has been introduced in literature.
しかし、レーザーによる液面測定法では液面が鏡面の如
く作用するため、静止液面では９に示すように正反射す
るが、通常は液面が波立っているため１０に示すように
２次元的振動反射をおこし、有効な反射光を捉えること
は困難である。However, in the liquid level measurement method using a laser, the liquid surface acts like a mirror surface, so a stationary liquid surface causes specular reflection as shown in 9, but normally the liquid surface is undulating, resulting in a two-dimensional reflection as shown in 10. It is difficult to capture the reflected light effectively.
また、レーザーを使わずにフュージョンリングを測光し
、フュージョンリングの存在する位置から融液面高さを
求めようとしても、光学的手段８に写し出される像から
は、フュージョンリング５の直径は測定できても、直接
融液面高さを求めることはできない。Furthermore, even if one attempts to photometer the fusion ring without using a laser and determine the melt surface height from the position of the fusion ring, the diameter of the fusion ring 5 cannot be measured from the image projected on the optical means 8. However, it is not possible to directly determine the melt surface height.
本発明は、光学的手段に受像されるフュージョンリング
像を使って、液面の波立ちに影響されることなく正確に
融液面高さを計測する方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 method for accurately measuring the height of a melt surface without being affected by ripples in the liquid surface using a fusion ring image received by an optical means.
（課題を解決するための手段）
本発明の方法は、ＣＺ法により融液から円柱状に引上げ
られる単結晶の成長部に生じるフュージョンリングを斜
上方より測光することにより、フュージョンリングの直
径に対応するピーク間の水平方向距離と、ピーク間中央
部における垂直方向のピーク位置とを測定し、測定され
た垂直方向のピーク位置にピーク間距離に基づく補正を
加えて融液面高さとするものである。(Means for Solving the Problems) The method of the present invention measures the diameter of the fusion ring by photometry from obliquely above the fusion ring that is generated in the growth area of a single crystal that is pulled into a cylindrical shape from the melt by the CZ method. The horizontal distance between the peaks and the vertical peak position at the center between the peaks are measured, and the measured vertical peak position is corrected based on the distance between the peaks to obtain the melt surface height. be.
（作 用〕
垂直方向のピーク位置にピーク間距離に基づく補正を加
えるので、液面の波立ちに関係なく、しかも光学的手段
にとらえられるフュージョンリング像の位置、大きさに
関係なく安定した融液面高さの計測を可能にする。(Function) Since the peak position in the vertical direction is corrected based on the distance between the peaks, the melt remains stable regardless of the ripples on the liquid surface and regardless of the position and size of the fusion ring image captured by optical means. Enables surface height measurement.
以下、本発明の方法を具体的に説明する。 The method of the present invention will be specifically explained below.
第１図に示すごとく、シリコン等の単結晶４はるつぼｌ
中の融液２より順次引上げられ、単結晶４の下部の融液
面に接する場所にフュージョンリング５が発生する。本
発明の方法においては、フュージョンリング５を光学的
手段８により観測窓７を通して測光する。As shown in Figure 1, a single crystal 4 of silicon, etc. is placed in a crucible l.
The fusion ring 5 is sequentially pulled up from the melt 2 inside, and a fusion ring 5 is generated at a location in contact with the melt surface at the bottom of the single crystal 4. In the method of the invention, the fusion ring 5 is photometered through the observation window 7 by optical means 8 .
フュージョンリングを測光する光学的手段８としては、
通常の光学的測定器によることもできるし、ＣＣＤカメ
ラによることもできる。ＣＣＤカメラによる場合は測定
線上でフュージョンリングのところがピークとして測光
される。そして、水平方向のピーク間距離を測定するこ
とによってフュージョンリングの直径が測定できる。ま
た垂直方向のピーク位置によって融液面高さに相当する
値が測定できる。The optical means 8 for photometering the fusion ring includes:
It can be measured by a normal optical measuring device or by a CCD camera. When using a CCD camera, the light is measured as a peak at the fusion ring on the measurement line. The diameter of the fusion ring can then be measured by measuring the distance between the peaks in the horizontal direction. Furthermore, a value corresponding to the height of the melt surface can be measured based on the peak position in the vertical direction.
第２図に一部元ＣＣＤカメラを使った装置の一例を示す
。水平方向測定部１６では、第１の一部元ＣＣＤカメラ
でフュージョンリングの直径が測定され、同じく垂直方
向計測部１７では、第２の一部元ＣＯＤカメラによりフ
ュージョンリングの中央部における垂直方向位置が測定
される。第３図は二次元ＣＣＤカメラを使って二次元視
野１８を捉えた例である。この例によるときも、水平方
向および水平方向中央における垂直方向の譚度分布が第
２図のときと同様、第４図の通り求まる。FIG. 2 shows an example of a device using a partial CCD camera. In the horizontal measuring section 16, the diameter of the fusion ring is measured with a first partial CCD camera, and in the vertical measuring section 17, the vertical position in the center of the fusion ring is measured with a second partial COD camera. is measured. FIG. 3 is an example of a two-dimensional field of view 18 captured using a two-dimensional CCD camera. According to this example, the horizontal direction and the vertical direction distribution at the center of the horizontal direction are determined as shown in FIG. 4, as in the case of FIG. 2.
そして、水平方向のピーク１９．１９間隔よりフュージ
ョンリングの直径が計測されるし、垂直方向のビー９２
０位置を液面高さの検出点とされる。Then, the diameter of the fusion ring is measured from the horizontal peak interval 19.19, and the vertical bead 92
The 0 position is taken as the detection point of the liquid level height.
ところで、光学的手段の視野に写し出されるフュージョ
ンリングの像は、第５図のごとく、垂直方向には短径、
水平方向には長径をもつ楕円状に写し出される。楕円は
前面部分のみ見える。そして光学的手段の視野１１の像
によって融液面高さが次の如く推定される。By the way, as shown in Fig. 5, the image of the fusion ring projected in the field of view of the optical means has the minor axis,
In the horizontal direction, it is projected as an ellipse with a major axis. Only the front part of the oval is visible. Then, the melt surface height is estimated as follows based on the image of the field of view 11 of the optical means.
融液面高さの基準となる検出点は垂直方向手前の短径上
のＡ点である。しかし実際は、リング中央位置の０点の
液面高さが液面測定の基準となる。The detection point that serves as a reference for the melt surface height is point A on the short axis in the vertical direction. However, in reality, the liquid level height at the zero point at the center of the ring is the standard for measuring the liquid level.
０点を通る水平線ＭＮを液面高さとして検知し得る液面
スケール１３が視野内に予めもうけられているとすれば
、Ａ点を同−融液面高さの状態で０点に移動すれば、そ
の位置の液面スケール１３の読みが融液面高さをあられ
すことになる。これを第６図により説明する。If a liquid level scale 13 that can detect the horizontal line MN passing through the 0 point as the liquid level height is previously created within the field of view, then move the point A to the 0 point at the same melt level level. For example, the reading on the liquid level scale 13 at that position will indicate the melt level height. This will be explained with reference to FIG.
光学的手段はレンズ１４と受像器１５とよりなり、受像
器１５上の視野１１に融液面上にあるフュージョンリン
グの像を結ぶ、リング中心線と測光方向中心線との角度
はθである。融液面上の検出点Ａ′を中央点０′まで動
かす場合を考えるならば、測光軸０−０′に垂直なＣ′
と０′との間隔０′はｌ ＝ Ｄ 、ＣＯ５θ／２で示
される。この間隔ρがレンズ１４を通して受像器１５に
中心０よりｌ′＝ ｌ ／ ｋ ＝ Ｄ ｏｃＯ５θ７
２Ｋ（但しＫは縮少倍率）だけ離れた像Ａ−０を結ぶ（
但し単レンズであるので倒立像となる）。The optical means consists of a lens 14 and an image receptor 15, and the image of the fusion ring on the melt surface is focused on the field of view 11 on the image receptor 15. The angle between the center line of the ring and the center line in the photometric direction is θ. . If we consider the case where the detection point A' on the melt surface is moved to the center point 0', C' perpendicular to the photometric axis 0-0'
The interval 0' between and 0' is expressed as l = D, CO5θ/2. This distance ρ passes through the lens 14 to the image receptor 15 from the center 0 to l'=l/k=DocO5θ7
Connect images A-0 separated by 2K (where K is the reduction magnification) (
However, since it is a single lens, the image will be inverted).
それ故、受像器１５の視野１１内において、受像画面上
の検出点Ａをｉ′だけ画面の中央方向にずらせば液面ス
ケールの融液面高さの表示点である０点を受像画面上に
指定することができる。この０点よって融液面高さが液
面スケール１３により測定される。Therefore, within the field of view 11 of the image receptor 15, if the detection point A on the image receiving screen is shifted toward the center of the screen by i', the 0 point, which is the display point of the melt surface height on the liquid level scale, can be set on the image receiving screen. can be specified. Based on this zero point, the melt level height is measured by the liquid level scale 13.
直径が製造時の公称直径Ｄ０であるときは、検出点Ａ点
より上方にｆｆｉ’＝Ｄ、ｃＯｓθ／２にだけ動かせば
よい。もし直径が公称直径より誤差Δｄ （−〇、−Ｄ
、）をもつ直径ＤＩであるときは、フュージョンリング
の融液面上の検出点Ｂ′は受像器１５上のＢ点に読みと
れる。検出点Ｂ点より上方にｌ′＋ΔＮ’＝ＤＯＣＯＳ
θ／２に＋Δｄ−ＣＯＳθ／２にだけ移動させて０点に
到らしめることができる。When the diameter is the nominal diameter D0 at the time of manufacture, it is only necessary to move it upward from the detection point A by ffi'=D, cOsθ/2. If the diameter is less than the nominal diameter, the error Δd (−〇, −D
, ), the detection point B' on the melt surface of the fusion ring is read as point B on the image receptor 15. l'+ΔN'=DOCOS above the detection point B
It is possible to reach the 0 point by moving only +Δd−COSθ/2 to θ/2.
以上の如くして実際に融液面高さを求め、これを一定に
保持した結果は次のとおりである。使用したＣＣＤカメ
ラの仕様は、
カメラ内の素子の数すなわちビクセル数： ２０４８視
野範囲：１００ｎａ＋＋
視野角 ＝２５゜
である。これによると融液面高さが
計測精度≦±０．２ｍ＋＋
で測定できる。The height of the melt surface was actually determined as described above and the height was kept constant, and the results are as follows. The specifications of the CCD camera used were as follows: Number of elements in the camera, ie, number of pixels: 2048 Viewing range: 100 na++ Viewing angle = 25°. According to this, the melt surface height can be measured with a measurement accuracy of ≦±0.2 m++.
融液面の高さを正確に求め、その変動を抑えることによ
り次の効果を得ることができた。By accurately determining the height of the melt surface and suppressing its fluctuations, we were able to obtain the following effects.
本発明法に基づく液面管理を行うことによって液面変化
の標準偏差σ１を±１０ａ＋＋から±１１唾と小さくし
得ることができた。By controlling the liquid level based on the method of the present invention, it was possible to reduce the standard deviation σ1 of the liquid level change from ±10a++ to ±11a++.
成長した単結晶内で多結晶構造のまま単結晶内に存在し
、単結晶の並びを壊している状態はＤＦ切れ（ＤＦは口
１ｓｌｏｃａｔｉｏｎ Ｆｒｅｅ 、すなわち無転位）
と言われている。融液面高さを一定に保持し、融液面と
ヒーター位置との変位を最適の状態にすることによって
、このＤＦ切れを減少させることができる。A state in which the polycrystalline structure remains within the single crystal as it grows and breaks the arrangement of the single crystal is called DF breakage (DF is location free, that is, no dislocations).
It is said that This DF breakage can be reduced by keeping the melt surface height constant and optimizing the displacement between the melt surface and the heater position.
成長して単結晶内に取り込まれる酸素濃度はＯｌと言わ
れている。るつぼ１成分中の酸素がシリコン融液にとり
込まれることによって酸素濃度が変化する。引上げられ
た単結晶４の長さ方向の０ムばらつきδ２は、融液面高
さ計測を行わないときに比べ、本発明の液面計測を行い
、液面高さを一定に保持することにより３０％に減少さ
せることができた。The oxygen concentration that is grown and incorporated into a single crystal is called Ol. The oxygen concentration changes as oxygen in one component of the crucible is taken into the silicon melt. The 0mm variation δ2 in the length direction of the pulled single crystal 4 is smaller when the liquid level is measured according to the present invention and the liquid level is kept constant, compared to when the melt level height is not measured. We were able to reduce it to 30%.
本発明によると、フュージョンリングの測光位置を補正
することによって直ちに正確な融液面高さを知ることが
でき、これにより高精度な融液面高さ管理を可能にし、
製品品質向上、及びこれにともなう製品歩留り向上に大
きな効果を発揮する。According to the present invention, by correcting the photometric position of the fusion ring, it is possible to immediately know the accurate melt surface height, thereby enabling highly accurate melt surface height management,
It is highly effective in improving product quality and product yield.
第１図はＣＺ法を示す模式図、第２図は一部元ＣＣＤカ
メラによるとき、また第３図は二次元ＣＣＤカメラによ
るときのフュージョンリングの受像範囲図、第４図はＣ
ＣＤカメラによるフュージョンリングの輝度分布図、第
５図は受像器視野に写し出されたフュージョンリングの
再検図、第６図はフュージョンリングと測光器との位置
関係を示す光路図、第７図はレーザーを利用した液面計
の模式図である。
ｌ：るつぼ、２：結晶融液、３：ワイヤ、４：単結晶、
５：フュージョンリング、６：チャンバ、７：観測窓、
８：光学的手段、９：正反射、１０ ：Ｈ動反射、１１
；視野、１２：電熱ヒータ、１３：液面スケール、１４
：レンズ、１５：受像器、１６ｊ水平方向計測部、１７
：垂直方向計測部、１８：二次元視野、１９：水平方向
のピーク、２０：垂直方向のピーク。
出 願 人 大阪チタニウム製造株式会社第
図Figure 1 is a schematic diagram showing the CZ method, Figure 2 is a partial image reception range diagram of the fusion ring when using an original CCD camera, Figure 3 is a diagram of the reception range of the fusion ring when using a two-dimensional CCD camera, and Figure 4 is the CZ method.
A brightness distribution diagram of the fusion ring taken by a CD camera. Figure 5 is a re-examination diagram of the fusion ring projected in the field of view of the image receiver. Figure 6 is an optical path diagram showing the positional relationship between the fusion ring and the photometer. Figure 7 is the laser. 1 is a schematic diagram of a liquid level gauge using l: crucible, 2: crystal melt, 3: wire, 4: single crystal,
5: Fusion ring, 6: Chamber, 7: Observation window,
8: Optical means, 9: Specular reflection, 10: H dynamic reflection, 11
; Field of view, 12: Electric heater, 13: Liquid level scale, 14
: Lens, 15: Image receptor, 16j Horizontal direction measurement section, 17
: Vertical direction measurement unit, 18: Two-dimensional visual field, 19: Horizontal direction peak, 20: Vertical direction peak. Applicant: Osaka Titanium Manufacturing Co., Ltd.
Claims (1)
の成長部に生じるフュージョンリングを斜上方より測光
することにより、フュージョンリングの直径に対応する
ピーク間の水平方向距離と、ピーク間中央部における垂
直方向のピーク位置とを測定し、測定された垂直方向の
ピーク位置にピーク間距離に基づく補正を加えて融液面
高さとすることを特徴とするＣＺ法における融液面高さ
の測定法。1. By photometrically measuring the fusion ring that occurs in the growth area of a single crystal that is pulled into a cylindrical shape from the melt using the CZ method from obliquely above, we can determine the horizontal distance between the peaks corresponding to the diameter of the fusion ring and the central area between the peaks. Measurement of the melt surface height in the CZ method, which is characterized in that the peak position in the vertical direction is measured and the measured peak position in the vertical direction is corrected based on the distance between the peaks to obtain the melt surface height. Law.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25793988A JPH02102187A (en) | 1988-10-12 | 1988-10-12 | Measurement of height of melt level in cz method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25793988A JPH02102187A (en) | 1988-10-12 | 1988-10-12 | Measurement of height of melt level in cz method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02102187A true JPH02102187A (en) | 1990-04-13 |
Family
ID=17313303
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25793988A Pending JPH02102187A (en) | 1988-10-12 | 1988-10-12 | Measurement of height of melt level in cz method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02102187A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7172656B2 (en) | 2003-05-06 | 2007-02-06 | Sumitomo Mitsubishi Silicon Corporation | Device and method for measuring position of liquid surface or melt in single-crystal-growing apparatus |
| WO2009028273A1 (en) * | 2007-08-24 | 2009-03-05 | Sumco Techxiv Corporation | Method for measuring liquid level in single crystal pulling apparatus employing cz method |
| JP2009084152A (en) * | 2008-12-16 | 2009-04-23 | Sumco Corp | Melt surface location detecting apparatus of single crystal pulling apparatus, and the single crystal pulling apparatus |
-
1988
- 1988-10-12 JP JP25793988A patent/JPH02102187A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7172656B2 (en) | 2003-05-06 | 2007-02-06 | Sumitomo Mitsubishi Silicon Corporation | Device and method for measuring position of liquid surface or melt in single-crystal-growing apparatus |
| WO2009028273A1 (en) * | 2007-08-24 | 2009-03-05 | Sumco Techxiv Corporation | Method for measuring liquid level in single crystal pulling apparatus employing cz method |
| JP2009051685A (en) * | 2007-08-24 | 2009-03-12 | Ｓｕｍｃｏ Ｔｅｃｈｘｉｖ株式会社 | Method for measuring level of liquid surface in apparatus for pulling single crystal by cz method |
| US8361223B2 (en) | 2007-08-24 | 2013-01-29 | Sumco Techxiv Corporation | Method for measuring liquid level in single crystal pulling apparatus employing CZ method |
| JP2009084152A (en) * | 2008-12-16 | 2009-04-23 | Sumco Corp | Melt surface location detecting apparatus of single crystal pulling apparatus, and the single crystal pulling apparatus |
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