JP2985540B2 - Manufacturing method of quartz glass - Google Patents
Manufacturing method of quartz glassInfo
- Publication number
- JP2985540B2 JP2985540B2 JP4318088A JP31808892A JP2985540B2 JP 2985540 B2 JP2985540 B2 JP 2985540B2 JP 4318088 A JP4318088 A JP 4318088A JP 31808892 A JP31808892 A JP 31808892A JP 2985540 B2 JP2985540 B2 JP 2985540B2
- Authority
- JP
- Japan
- Prior art keywords
- homogeneity
- quartz glass
- temperature
- heat treatment
- rate
- 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 - Lifetime
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B32/00—Thermal after-treatment of glass products not provided for in groups C03B19/00, C03B25/00 - C03B31/00 or C03B37/00, e.g. crystallisation, eliminating gas inclusions or other impurities; Hot-pressing vitrified, non-porous, shaped glass products
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
- Y02P40/57—Improving the yield, e-g- reduction of reject rates
Landscapes
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
- Glass Melting And Manufacturing (AREA)
- Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)
- Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、石英ガラスの製造方法
に関するものであり、特に均質性Δｎ＝１×１０-6以下
の高均質性が要求される合成石英ガラス部材を必要とす
る分野、例えば光リソグラフィ−、高精度分光器、レ−
ザ−等の精密光学機器に有用とされる高均質な光学用合
成石英ガラスの製造法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing quartz glass, and more particularly to a field requiring a synthetic quartz glass member requiring high homogeneity of not more than .DELTA.n = 1.times.10.sup.- 6 . For example, optical lithography, high precision spectroscope, laser
The present invention relates to a method for producing highly homogeneous synthetic quartz glass for optics, which is useful for precision optical instruments such as lasers.
【０００２】[0002]
【従来の技術】従来、シリコン等のウエハ上に集積回路
の微細パターンを露光・転写する光リソグラフィ技術に
おいては、ステッパーと呼ばれる露光装置が用いられ
る。このステッパーの光源は、近年のＬＳＩの高集積化
に伴ってｇ線（４３６ｎｍ）からｉ線（３６５ｎｍ）、
さらにはＫｒＦ（２４８ｎｍ）やＡｒＦ（１９３ｎｍ）
エキシマレ−ザ−へと短波長化が進められている。2. Description of the Related Art Conventionally, in an optical lithography technique for exposing and transferring a fine pattern of an integrated circuit onto a wafer such as silicon, an exposure apparatus called a stepper is used. The light source of this stepper has been changed from g-line (436 nm) to i-line (365 nm) with high integration of LSI in recent years.
Furthermore, KrF (248 nm) and ArF (193 nm)
Shorter wavelengths are being developed for excimer lasers.
【０００３】一般に、ステッパーの照明系あるいは投影
レンズとして用いられる光学ガラスは、ｉ線よりも短い
波長領域では光透過率が低下するため、従来の光学ガラ
スにかえて合成石英ガラスやＣａＦ2（蛍石）等のフッ
化物単結晶を用いることが提案されている。また、より
高精度の光学系が必要とされることから光学ガラスの均
質性（屈折率のばらつき）に対する要求もきびしくな
り、Δｎ＝１×１０-6以下の高均質な合成石英ガラスの
需要が大幅に増える可能性が高い。In general, optical glass used as an illumination system or a projection lens of a stepper has a low light transmittance in a wavelength region shorter than the i-line, so that synthetic quartz glass or CaF 2 (fluorescent) is used instead of conventional optical glass. It has been proposed to use a single crystal of fluoride such as stone). Further, since a higher-precision optical system is required, the requirement for the homogeneity (variation in refractive index) of the optical glass becomes more severe, and the demand for a highly homogeneous synthetic quartz glass having Δn = 1 × 10 −6 or less is increasing. It is likely to increase significantly.
【０００４】一般に、合成石英ガラスは、製造方法に起
因する屈折率勾配（密度勾配）が生じることが多く、高
均質用途としては歩留まりが悪いことが大きな問題とな
る。この屈折率の不均質の原因はＯＨ基濃度やＣｌ濃
度、仮想温度分布、応力等によることが予測されるが、
未だ明らかにされていない。ところで、ガラスの軟化点
が比較的低い一般の光学ガラス（例えば硼珪クラウンガ
ラスやリン酸塩系ガラス）では、均質な屈折率分布を得
るために一旦合成したガラスを高温に再加熱して機械的
に攪拌することにより均質化をおこなっている。しかし
ながら、石英ガラスでは、常圧で高温に加熱すると粘度
が機械的攪拌を行なうのに充分な程度に低下するより前
に昇華が著しくなるので機械的攪拌によって均質化する
ことは困難である。そこで、機械的攪拌のかわりに高圧
のアルゴンガス雰囲気中で熱処理を行なう均質化方法が
用いられている。例えば、２気圧以上の圧力のアルゴン
ガス雰囲気中で１８００℃以上に加熱することにより、
脈理等の目視で認められる程度の屈折率の不均質分布
（Δｎ＝１０-4程度）を取り除いている（特開昭62−15
8121）。こうして均質化された石英ガラスの均質性は、
Δｎ＝１０-5程度である。[0004] In general, synthetic quartz glass often has a refractive index gradient (density gradient) due to the manufacturing method, and a serious problem is that the yield is poor for highly homogeneous applications. The cause of the inhomogeneity of the refractive index is predicted to be due to OH group concentration, Cl concentration, fictive temperature distribution, stress, etc.
Not yet disclosed. In general optical glass having a relatively low softening point (for example, borosilicate crown glass or phosphate glass), once synthesized glass is reheated to a high temperature in order to obtain a uniform refractive index distribution. The mixture is homogenized by agitation. However, quartz glass is difficult to homogenize by mechanical agitation because heating the glass to high temperature at normal pressure causes the sublimation to become significant before the viscosity is reduced to a level sufficient for mechanical agitation. Therefore, a homogenization method in which heat treatment is performed in a high-pressure argon gas atmosphere instead of mechanical stirring is used. For example, by heating to 1800 ° C. or more in an argon gas atmosphere at a pressure of 2 atm or more,
The inhomogeneous distribution of the refractive index (approximately Δn = 10 −4 ) which is visually recognized such as striae is removed (JP-A-62-15).
8121). The homogeneity of the quartz glass thus homogenized
Δn = about 10 −5 .
【０００５】[0005]
【発明が解決しようとする課題】従来の石英ガラスの製
造方法では、１８００℃以上のカ−ボン製の特殊な高温
炉や消耗品となるカ−ボン型等が必要となること、また
高温で処理するため母材周辺部の変質のため歩留まりが
低くなり、さらには特殊な工程を必要とするためコスト
アップすることなどの問題が生じた。The conventional method for producing quartz glass requires a special high-temperature furnace made of carbon at 1800 ° C. or higher, a carbon mold as a consumable, and the like. Because of the deterioration of the peripheral portion of the base material due to the treatment, the yield is lowered, and furthermore, a special process is required, which raises a problem such as an increase in cost.
【０００６】しかしながら、最も問題となるのは、この
ような従来の製造方法においては、合成時に形成される
径方向の諸物性差の影響を強く受け、完全に均質性を向
上することが出来ないことである。さらには、処理後の
均質性を予測することも困難であると共に所定の均質性
に調整することが出来ないため、低い歩留まりでしか均
質性の向上した合成石英ガラスを得ることができない。However, what is most problematic is that in such a conventional manufacturing method, the uniformity cannot be completely improved due to the strong influence of various physical properties formed in the radial direction at the time of synthesis. That is. Further, it is difficult to predict the homogeneity after the treatment, and it is not possible to adjust the homogeneity to a predetermined value. Therefore, a synthetic quartz glass with improved homogeneity can be obtained only at a low yield.
【０００７】本発明では、このような問題を解決し、均
質性の向上した石英ガラスを歩留りよく得ることの可能
な石英ガラスの製造方法を提供することを目的とする。[0007] It is an object of the present invention to solve the above problems and to provide a method for producing quartz glass capable of obtaining quartz glass with improved homogeneity with good yield.
【０００８】[0008]
【課題を解決するための手段】そこで、本発明者らは、
石英ガラスの製造方法に起因する屈折率の不均質性がど
のような製造条件にどの程度影響されるのかを鋭意研究
したところ、以下のことがわかった。 合成した石英ガラスによって、同じ熱処理をしても
得られるΔｎの値はそれぞれ異なる。 熱処理の際の降温速度を変化させることにより、任
意のΔｎが得られる。Means for Solving the Problems Accordingly, the present inventors have:
The inventors of the present invention have conducted intensive studies on how the inhomogeneity of the refractive index caused by the quartz glass manufacturing method is affected by what manufacturing conditions, and found the following. The value of Δn obtained by the same heat treatment differs depending on the synthesized quartz glass. By changing the temperature drop rate during the heat treatment, an arbitrary Δn can be obtained.
【０００９】そして、さらに研究を進めた結果、降温速
度の対数とΔｎの値をグラフに表すことにより、所望の
Δｎを与える降温速度を予想できることを見い出し、本
発明を成すに至った。よって、本発明は第１に、均質性
（屈折率のばらつき）Δｎ＝１×１０-6以上の石英ガラ
スを大気中または不活性ガス（例えばＮ2ガス、アルゴ
ンガス、ヘリウムガス）雰囲気中または水素ガス雰囲気
中で９００〜１３００℃に保持し、降温速度を調整して
熱処理することを特徴とするΔｎ＝１×１０-6以下の石
英ガラスの製造方法（請求項１）を提供する。As a result of further study, the present inventors have found that the logarithm of the cooling rate and the value of Δn can be represented on a graph to predict the cooling rate giving a desired Δn, thereby completing the present invention. Accordingly, the present invention firstly provides a quartz glass having a homogeneity (variation in refractive index) Δn = 1 × 10 −6 or more in the air or in an inert gas (eg, N 2 gas, argon gas, helium gas) atmosphere or A method for producing quartz glass with Δn = 1 × 10 −6 or less, characterized in that heat treatment is performed while maintaining the temperature at 900 to 1300 ° C. in a hydrogen gas atmosphere and adjusting the temperature decreasing rate (claim 1).
【００１０】なお、雰囲気は、大気、不活性ガス、水素
ガス雰囲気であるが、あるいはこれらの混合ガスとして
もよい。また、本発明は第２に、横軸が降温速度の対
数、縦軸が均質性Δｎのグラフに予め求めた２以上の座
標点をプロットして得られた直線または曲線から所望の
Δｎを与える降温速度を求め、これを前記降温速度とす
ることを特徴とする石英ガラスの製造方法（請求項２）
を提供する。The atmosphere is an atmosphere of an air, an inert gas or a hydrogen gas, or may be a mixed gas of these. Secondly, the present invention gives a desired Δn from a straight line or a curve obtained by plotting two or more coordinate points obtained in advance on a graph in which the horizontal axis is the logarithm of the cooling rate and the vertical axis is the graph of homogeneity Δn. A method for producing quartz glass, wherein a rate of temperature decrease is determined, and this is used as the rate of temperature decrease.
I will provide a.
【００１１】保持温度は９００℃〜１３００℃であるの
は、石英ガラスの歪点（約１０００℃）を考慮すると９
００℃以下では応力緩和の効果が期待できないこと、ま
た１３００℃以上では表面失透の影響が無視できなくな
るためである。なお、特開平3ー109233では、仮想温度分
布（熱処理により調整する）の平坦化には限界があるた
め、それにより生じる屈折率分布をＯＨ分布で打ち消す
方法が述べられているが、本発明ではＯＨ等の不純物分
布を制御することなしに、熱処理のみで均質性を所望の
値に調整することが可能な点に特徴を持つ。The reason why the holding temperature is 900 ° C. to 1300 ° C. is 9 considering the strain point (about 1000 ° C.) of quartz glass.
This is because the effect of stress relaxation cannot be expected at a temperature of 00 ° C. or less, and the effect of surface devitrification cannot be ignored at a temperature of 1300 ° C. or more. In Japanese Patent Application Laid-Open No. 3-109233, there is a limit to the flattening of the virtual temperature distribution (adjusted by heat treatment), and a method of canceling out the resulting refractive index distribution with the OH distribution is described. It is characterized in that the homogeneity can be adjusted to a desired value only by heat treatment without controlling the distribution of impurities such as OH.
【００１２】[0012]
【作用】上述した均質性を向上（Δｎの値を小さくす
る）、または所定のΔｎ値に調節する本発明の製造方法
を以下に詳細に説明する。本発明の石英ガラスの製造方
法は、様々なΔｎ値、或いはΔｎパターンをもつ合成石
英ガラスを様々な熱処理の処理条件で長期に渡って実験
した結果、見い出されたものである。図１に本発明の製
造方法の一例の結果を示す。これは、保持温度、保持時
間、放冷温度を１０００℃、１０ｈ、５００℃と一定に
し、同一の石英ガラス試料を降温速度を１〜１００℃／
ｈの間の数点の処理条件で熱処理し、そのΔｎ値と降温
速度の関係をプロットしたグラフである。The production method of the present invention for improving the above-mentioned homogeneity (decreasing the value of Δn) or adjusting it to a predetermined value of Δn will be described in detail below. The method for producing quartz glass of the present invention has been found as a result of long-term experiments on synthetic quartz glass having various Δn values or Δn patterns under various heat treatment conditions. FIG. 1 shows the results of an example of the production method of the present invention. This means that the holding temperature, holding time, and cooling temperature are kept constant at 1000 ° C., 10 h, and 500 ° C., and the same quartz glass sample is cooled at a rate of 1 to 100 ° C. /
7 is a graph plotting the relationship between the Δn value and the rate of temperature decrease after heat treatment under several processing conditions during the time h.
【００１３】降温速度の範囲は、特に限られたものでは
ないが、速すぎると降温速度によるΔｎの変動が大きす
ぎて均質性を向上できなくなり、遅すぎると熱処理に時
間がかかり、歩留りを向上できなくなる。また、図１に
示す製造方法においては、熱処理を常圧下で行ったが、
例えば、脱ガス処理のためには減圧下で行ない、水素ド
ープのためには水素雰囲気、加圧下で行なうことが可能
である。[0013] The range of the cooling rate is not particularly limited, but if it is too fast, the variation of Δn due to the cooling rate is too large to improve the homogeneity, and if it is too slow, the heat treatment takes time and the yield is improved. become unable. In the manufacturing method shown in FIG. 1, the heat treatment was performed under normal pressure.
For example, degassing can be performed under reduced pressure, and hydrogen doping can be performed under a hydrogen atmosphere and under pressure.
【００１４】試料の均質性Δｎは、レーザー干渉計を用
いてオイルオンプレート法で測定した。図１のグラフ
は、単に不十分な熱処理を繰り返したことによりΔｎが
変化していったものではなく、数回の様々な降温速度で
熱処理した後、再び最初の条件で熱処理した場合、元の
Δｎに戻ることが確認されている。このように、同一の
合成石英ガラス試料においては、降温速度とΔｎは１対
１で対応する。The homogeneity Δn of the sample was measured by an oil-on-plate method using a laser interferometer. The graph of FIG. 1 shows that Δn did not change simply due to repeated insufficient heat treatment. After heat treatment was performed several times at various temperature decreasing rates and then heat treatment was again performed under the initial conditions, It has been confirmed that the value returns to Δn. As described above, in the same synthetic quartz glass sample, the cooling rate and Δn correspond one-to-one.
【００１５】このグラフを作成することで、本発明者ら
は、Δｎ値と降温速度の対数がほぼ直線関係にあること
を初めて発見した。直線の傾きは、合成条件及びガラス
内の不純物分布により変化する。従って、この現象を利
用し熱処理を数回行なってグラフを作成した後は、降温
速度を調整することにより、合成石英ガラスの均質性Δ
ｎを向上すること及び任意の値にΔｎ値を調整すること
が可能になった。By creating this graph, the present inventors have discovered for the first time that the logarithm of the Δn value and the logarithm of the temperature drop have a substantially linear relationship. The slope of the straight line changes depending on the synthesis conditions and the impurity distribution in the glass. Therefore, after making a graph by performing heat treatment several times by utilizing this phenomenon, the homogeneity Δ of the synthetic quartz glass is adjusted by adjusting the cooling rate.
It has become possible to improve n and to adjust the Δn value to an arbitrary value.
【００１６】なお、本発明では、表現上、グラフを作成
して降温速度を調整するが、２以上の降温速度で熱処理
した際の降温速度の対数と均質性Δｎの値から関係式を
導き出せば、グラフを作成しなくとも所望のΔｎを与え
る降温速度が得られる。これも本発明の範疇である。本
発明の利用する現象は、通常のＢＫ７（硼珪クラウン）
等の光学ガラスでは確認されておらず、合成石英ガラス
固有の現象である。例えば、通常の光学ガラスは、熱処
理の降温速度（徐冷速度）を遅くすればするほど均質性
は向上すると考えられている。In the present invention, in terms of expression, a graph is created to adjust the cooling rate. If a relational expression is derived from the logarithm of the cooling rate and the value of the homogeneity Δn when the heat treatment is performed at the cooling rate of 2 or more. Thus, a temperature drop rate that gives a desired Δn can be obtained without creating a graph. This is also within the scope of the present invention. The phenomenon used in the present invention is a normal BK7 (borosilicate crown)
It has not been confirmed in optical glasses such as those described above, and is a phenomenon unique to synthetic quartz glass. For example, it is considered that the homogeneity of ordinary optical glass is improved as the cooling rate (slow cooling rate) of the heat treatment is reduced.
【００１７】この合成石英ガラス固有の現象の起こる原
因は未だ明確にはなっていないが、ある程度の推測は出
来る。つまり、合成石英ガラスはその製造方法から推定
して合成されたインゴットの径方向にＯＨ基、Ｃｌ等の
不純物分布並びに温度分布に起因した諸物性差が存在す
る。このことから、この現象は、一般の光学ガラスには
存在しない径方向の諸物性差に起因していると考えられ
る。そして、熱処理の処理条件を変えることでこれらの
物性値が一様に変化しないこと、及び合成石英ガラス中
のこのような径方向の物性差によって応力分布の変化も
影響を受けることで、均質性が一般のＢＫ７などの光学
ガラスと異なった挙動を示すと考えられる。Although the cause of the phenomenon inherent in the synthetic quartz glass has not been clarified yet, it can be estimated to some extent. In other words, synthetic quartz glass has various physical properties due to the distribution of impurities such as OH groups and Cl and the temperature distribution in the radial direction of the synthesized ingot estimated from the manufacturing method. From this, it is considered that this phenomenon is caused by a difference in various physical properties in the radial direction that does not exist in general optical glass. By changing the processing conditions of the heat treatment, these physical property values do not change uniformly, and the change in stress distribution is also affected by such a difference in the physical properties in the synthetic quartz glass, resulting in homogeneity. Is considered to behave differently from optical glass such as general BK7.
【００１８】このように、数種の要因の複合作用で、均
質性Δｎが変化していると推測される。以下、実施例に
より、本発明を詳しく説明する。試料には、同一の石英
ガラスを色々な初期条件で熱処理（アニール）した様々
なΔｎパターンの約φ100〜150×ｔ40の円柱形状のもの
を用い、本発明の石英ガラスの製造方法により再熱処理
した。As described above, it is presumed that the homogeneity Δn is changed by the combined action of several factors. Hereinafter, the present invention will be described in detail with reference to examples. As the sample, the same quartz glass was subjected to heat treatment (annealing) under various initial conditions in a cylindrical shape of about φ100 to 150 × t40 with various Δn patterns, and re-heat treated by the quartz glass manufacturing method of the present invention. .
【００１９】本発明の製造方法により再熱処理を行った
ときの均質性の挙動を実施例１〜４に、また、それに対
応した径方向の均質性（屈折率分布）の変化を図２〜５
に示す。Examples 1 to 4 show the behavior of homogeneity when re-heat treatment is performed by the production method of the present invention, and FIGS. 2 to 5 show changes in radial homogeneity (refractive index distribution) corresponding thereto.
Shown in
【００２０】[0020]
【実施例１】 大気中、保持温度１０５０℃１０ｈ保持１℃／ｈ降
温５００℃放冷で、以下の品質の試料をイニシャルとし
て用いた。 再熱処理前の品質：均質性Δｎ＝４×１０-6、歪量＝
０．４nm/cm これを、大気中、保持温度１０５０℃１０ｈ保持１
０℃／ｈ降温５００℃放冷の条件で再熱処理を行うこと
で、以下の品質に良化または調整することが出来た。Example 1 A sample having the following quality was used as an initial in the air at a holding temperature of 1050 ° C. for 10 hours, a holding temperature of 1 ° C./h, and a cooling of 500 ° C. Quality before reheat treatment: homogeneity Δn = 4 × 10 −6 , strain amount =
0.4nm / cm This was held in air at a holding temperature of 1050 ° C for 10 hours.
By performing the reheat treatment under the condition of 0 ° C./h cooling at 500 ° C., the following quality could be improved or adjusted.
【００２１】再熱処理後の品質：Δｎ＝１×１０-6、歪
量＝０．７nm/cmQuality after reheat treatment: Δn = 1 × 10 −6 , strain amount = 0.7 nm / cm
【００２２】[0022]
【実施例２】 大気中、保持温度１０５０℃１０ｈ保持１℃／ｈ降
温５００℃放冷で、以下の品質の試料をイニシャルとし
て用いた。 再熱処理前の品質：Δｎ＝８×１０-6、歪量＝０．４nm
/cm これを、大気中、保持温度１０５０℃１０ｈ保持８
０℃／ｈ降温５００℃放冷の条件で再熱処理を行うこと
で、以下の品質に良化または調整することが出来た。Example 2 A sample having the following quality was used as an initial in the air at a holding temperature of 1050 ° C. for 10 h, a holding temperature of 1 ° C./h, and a cooling of 500 ° C. Quality before re-heat treatment: Δn = 8 × 10 −6 , strain amount = 0.4 nm
/ cm This is held in air at a holding temperature of 1050 ° C for 10 hours.
By performing the reheat treatment under the condition of 0 ° C./h cooling at 500 ° C., the following quality could be improved or adjusted.
【００２３】再熱処理後の品質：Δｎ＝１×１０-6、歪
量＝１．８nm/cmQuality after reheat treatment: Δn = 1 × 10 −6 , strain amount = 1.8 nm / cm
【００２４】[0024]
【実施例３】 大気中、保持温度１０５０℃１０ｈ保持１０℃／ｈ
降温５００℃放冷で以下の品質の試料をイニシャルとし
て用いた。 再熱処理前の品質：Δｎ＝５×１０-6、歪量＝０．７nm
/cm これを、大気中、保持温度１０５０℃１０ｈ保持１
℃／ｈ降温５００℃放冷の条件で再熱処理を行うこと
で、以下の品質に良化または調整することが出来た。[Example 3] In air, holding temperature 1050 ° C for 10 hours, holding 10 ° C / h
Samples of the following qualities were used as initials after cooling at 500 ° C. Quality before re-heat treatment: Δn = 5 × 10 −6 , strain amount = 0.7 nm
/ cm This is held in air at a holding temperature of 1050 ° C for 10 hours.
By performing the re-heat treatment under the condition of cooling at a temperature of 500 ° C./h and cooling at a temperature of 500 ° C., the following quality could be improved or adjusted.
【００２５】再熱処理後の品質：Δｎ＝２×１０-6、歪
量＝０．４nm/cmQuality after reheat treatment: Δn = 2 × 10 −6 , strain amount = 0.4 nm / cm
【００２６】[0026]
【実施例４】 大気中、保持温度１０５０℃１０ｈ保持１０℃／ｈ
降温５００℃放冷で以下の品質の試料をイニシャルとし
て用いた。 再熱処理前の品質：Δｎ＝３×１０-6、歪量＝０．６nm
/cm これを、大気中、保持温度１０５０℃１０ｈ保持１
℃／ｈ降温５００℃放冷の条件で再熱処理を行うこと
で、以下の品質に良化または調整することが出来た。[Example 4] In air, holding temperature 1050 ° C for 10h, holding 10 ° C / h
Samples of the following qualities were used as initials after cooling at 500 ° C. Quality before reheat treatment: Δn = 3 × 10 −6 , strain amount = 0.6 nm
/ cm This is held in air at a holding temperature of 1050 ° C for 10 hours.
By performing the re-heat treatment under the condition of cooling at a temperature of 500 ° C./h and cooling at a temperature of 500 ° C., the following quality could be improved or adjusted.
【００２７】再熱処理後の品質：Δｎ＝１×１０-6、歪
量＝０．２nm/cmQuality after reheat treatment: Δn = 1 × 10 −6 , strain amount = 0.2 nm / cm
【００２８】[0028]
【発明の効果】本発明の石英ガラスの製造方法によれ
ば、Δｎパターンの良好でない均質性Δｎ＝１×１０-6
以上の石英ガラスを、屈折率勾配を低くしΔｎ＝１×１
０-6程度以下にすることができる。つまり均質性を向上
することが可能となる。また、熱処理の処理条件を調整
することで所望のΔｎ値にすることも可能となる。この
技術を応用することで、ステッパー用投影レンズをはじ
めとした高均質合成石英ガラスを低コストで確実に製造
することが可能となる。According to the method for manufacturing quartz glass of the present invention, the poor uniformity of the Δn pattern Δn = 1 × 10 −6.
The above quartz glass is reduced in refractive index gradient by Δn = 1 × 1
It can be about 0 -6 or less. That is, the homogeneity can be improved. Further, by adjusting the processing conditions of the heat treatment, a desired Δn value can be obtained. By applying this technology, it is possible to reliably manufacture a highly homogeneous synthetic quartz glass including a projection lens for a stepper at low cost.
【図１】 Δｎ値と降温速度の関係をプロットしたグラ
フである。FIG. 1 is a graph in which a relationship between a Δn value and a temperature decrease rate is plotted.
【図２】 本発明の石英ガラスの製造方法により再熱処
理を行ったときの径方向の屈折率分布（均質性）の変化
の一実施例を示す図である。FIG. 2 is a view showing an example of a change in a refractive index distribution (homogeneity) in a radial direction when re-heat treatment is performed by the method for manufacturing quartz glass of the present invention.
【図３】 本発明の石英ガラスの製造方法により再熱処
理を行ったときの径方向の屈折率分布（均質性）の変化
の一実施例を示す図である。FIG. 3 is a view showing an example of a change in a refractive index distribution (homogeneity) in a radial direction when a re-heat treatment is performed by the method for manufacturing quartz glass of the present invention.
【図４】 本発明の石英ガラスの製造方法により再熱処
理を行ったときの径方向の屈折率分布（均質性）の変化
の一実施例を示す図である。FIG. 4 is a view showing an example of a change in a refractive index distribution (homogeneity) in a radial direction when a re-heat treatment is performed by the method for manufacturing quartz glass of the present invention.
【図５】 本発明の石英ガラスの製造方法により再熱処
理を行ったときの径方向の屈折率分布（均質性）の変化
の一実施例を示す図である。FIG. 5 is a diagram showing an example of a change in a refractive index distribution (homogeneity) in a radial direction when re-heat treatment is performed by the method for manufacturing quartz glass of the present invention.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平５−24856（ＪＰ，Ａ) 特開 平５−170466（ＪＰ，Ａ) 特開 平６−107421（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) C03B 20/00 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-24856 (JP, A) JP-A-5-170466 (JP, A) JP-A-6-107421 (JP, A) (58) Field (Int.Cl. 6 , DB name) C03B 20/00
Claims (3)
ラスの製造方法において、 降温速度と均質性Δｎとの関係から所望の均質性Δｎを
与える降温速度を求める工程と、均質性Δｎ＝１×１０
-6以上の石英ガラスを大気中または不活性ガス雰囲気中
または水素ガス雰囲気中で９００℃以上１３００℃以下
の所定温度に保持した後、前記所望の均質性Δｎを与え
る降温速度にて降温する熱処理工程と、 を有することを特徴とする石英ガラスの製造方法。1. A method for producing a quartz glass having a homogeneity Δn of about 1 × 10 −6 or less, wherein a step of obtaining a temperature lowering rate that gives a desired homogeneity Δn from a relationship between the temperature lowering rate and the homogeneity Δn; Δn = 1 × 10
-6 or more quartz glass is maintained at a predetermined temperature of 900 ° C. or more and 1300 ° C. or less in the atmosphere, in an inert gas atmosphere, or in a hydrogen gas atmosphere, and then cooled at a temperature lowering rate that gives the desired homogeneity Δn. A method for producing quartz glass, comprising the steps of:
ラスの製造方法において、 横軸が降温速度の対数、縦軸が均質性Δｎのグラフに２
以上の条件で熱処理したときの降温速度と均質性Δｎと
の関係を各々プロットして得られた直線または曲線から
所望の均質性Δｎを与える降温速度を求める工程と、 均質性Δｎ＝１×１０-6以上の石英ガラスを大気中また
は不活性ガス雰囲気中または水素ガス雰囲気中で９００
℃以上１３００℃以下の所定温度に保持した後、前記所
望のΔｎを与える降温速度にて降温する熱処理工程と、 を有することを特徴とする石英ガラスの製造方法。2. A method for producing quartz glass having a homogeneity Δn of about 1 × 10 −6 or less, wherein the abscissa represents the logarithm of the cooling rate and the ordinate represents the homogeneity Δn.
A step of obtaining a cooling rate that gives a desired uniformity Δn from a straight line or a curve obtained by plotting the relationship between the cooling rate and the homogeneity Δn when the heat treatment is performed under the above conditions; and homogeneity Δn = 1 × 10 -6 or more quartz glass in air, inert gas atmosphere or hydrogen gas atmosphere
A heat treatment step of maintaining the temperature at a predetermined temperature of not less than 1300 ° C. and not more than 1300 ° C., and then lowering the temperature at a temperature lowering rate that gives the desired Δn.
ラスの製造方法において、 均質性Δｎ＝１×１０-6以下の石英ガラスを、大気中ま
たは不活性ガス雰囲気中または水素ガス雰囲気中で９０
０℃以上１３００℃以下の所定温度に保持した後、所定
の降温速度で降温する第１の熱処理工程と、 前記第１の熱処理工程の降温速度と得られた石英ガラス
の均質性Δｎと、予め求めた降温速度と均質性Δｎとの
関係から、所望の均質性Δｎを与える降温速度を求める
工程と、 前記第１の熱処理を行った石英ガラスを大気中または不
活性ガス雰囲気中または水素ガス雰囲気中で９００℃以
上１３００℃以下の所定温度に保持した後、前記所望の
均質性Δｎを与える降温速度にて降温する第２の熱処理
工程と、 を有することを特徴とする石英ガラスの製造方法。3. A method for producing quartz glass having a homogeneity Δn of about 1 × 10 −6 or less, wherein the quartz glass having a homogeneity of Δn = 1 × 10 −6 or less is placed in the air, in an inert gas atmosphere, or in a hydrogen gas atmosphere. 90 in the atmosphere
A first heat treatment step of maintaining the temperature at 0 ° C. or more and 1300 ° C. or less and then decreasing the temperature at a predetermined temperature decreasing rate; and a temperature decreasing rate of the first heat treating step and the homogeneity Δn of the obtained quartz glass. A step of obtaining a temperature lowering rate that gives a desired homogeneity Δn from the relationship between the obtained temperature lowering rate and the homogeneity Δn; and placing the quartz glass subjected to the first heat treatment in the air, in an inert gas atmosphere, or in a hydrogen gas atmosphere. A second heat treatment step of maintaining a predetermined temperature in the range of 900 ° C. or more and 1300 ° C. or less and then lowering the temperature at a temperature lowering rate that gives the desired homogeneity Δn.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4318088A JP2985540B2 (en) | 1992-11-27 | 1992-11-27 | Manufacturing method of quartz glass |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4318088A JP2985540B2 (en) | 1992-11-27 | 1992-11-27 | Manufacturing method of quartz glass |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06166527A JPH06166527A (en) | 1994-06-14 |
| JP2985540B2 true JP2985540B2 (en) | 1999-12-06 |
Family
ID=18095350
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4318088A Expired - Lifetime JP2985540B2 (en) | 1992-11-27 | 1992-11-27 | Manufacturing method of quartz glass |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2985540B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69629119T2 (en) * | 1995-09-12 | 2004-04-15 | Corning Inc. | POT TO MAKE SILICAGLAS |
| DE69635662T2 (en) * | 1995-09-12 | 2006-08-10 | Corning Inc. | Method and furnace for producing fused silica fused silica |
| DE69634667T2 (en) * | 1995-09-12 | 2006-04-27 | Corning Inc. | BOULE OSCILLATION PATTERN FOR THE PRODUCTION OF MELTED QUARTZ GLASS |
| WO2001012566A1 (en) * | 1999-08-12 | 2001-02-22 | Nikon Corporation | Method for preparation of synthetic vitreous silica and apparatus for heat treatment |
| JP3975334B2 (en) * | 2002-04-01 | 2007-09-12 | 信越化学工業株式会社 | Heat treatment method for synthetic quartz glass |
| JP6830855B2 (en) * | 2017-04-24 | 2021-02-17 | 信越石英株式会社 | Manufacturing method of synthetic quartz glass |
-
1992
- 1992-11-27 JP JP4318088A patent/JP2985540B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06166527A (en) | 1994-06-14 |
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