JP2861512B2 - Manufacturing method of quartz glass optical member - Google Patents
Manufacturing method of quartz glass optical memberInfo
- Publication number
- JP2861512B2 JP2861512B2 JP20748691A JP20748691A JP2861512B2 JP 2861512 B2 JP2861512 B2 JP 2861512B2 JP 20748691 A JP20748691 A JP 20748691A JP 20748691 A JP20748691 A JP 20748691A JP 2861512 B2 JP2861512 B2 JP 2861512B2
- Authority
- JP
- Japan
- Prior art keywords
- quartz glass
- temperature
- optical member
- manufacturing
- glass body
- 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
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、高エネルギー密度の光
学系に用いられるミラー、レンズ、エタロン、フィルタ
ー、プリズム等の光学部材に適合する高均質な紫外線レ
ーザー用石英ガラス光学部材の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly uniform ultraviolet ray laser which is suitable for optical members such as mirrors, lenses, etalons, filters, prisms and the like used in high energy density optical systems.
The present invention relates to a method for manufacturing a quartz glass optical member for a laser .
【０００２】[0002]
【従来の技術】石英ガラスは、近赤外から真空紫外域ま
での広範囲にわたって透明な材料であることならびに寸
法安定性に優れることのために、高エネルギー密度の光
を用いる光学系のための光学部材としても最適な材料で
ある。しかしながら、石英ガラスは通常用いられる光学
ガラスに比較して溶融温度が高く、通常用いられる光学
ガラスを徐冷して脈理（屈折率の変動）を除去する温度
域では徐冷が困難で、屈折率の変動のない光学用石英ガ
ラスを得ることは困難であった。2. Description of the Related Art Quartz glass is a transparent material over a wide range from the near infrared to the vacuum ultraviolet region and has excellent dimensional stability. It is the most suitable material for the member. However, quartz glass has a higher melting temperature than commonly used optical glass, and it is difficult to gradually cool the commonly used optical glass in a temperature range where the striae (fluctuation in refractive index) is removed by slow cooling. It was difficult to obtain a quartz glass for optics with no change in the rate.
【０００３】このような高温度での熱処理により石英ガ
ラス中の脈理を除去する方法としては、例えば特開昭６
２−１５８１２１号には、高純度石英ガラスを１８００
℃以上の高温で溶融させた上に、２気圧以上の静水圧力
下で処理する方法が開示されている。しかしながら、こ
のような高温高圧に耐え得る装置は、必然的に大がかり
となり高価とならざるを得ない。A method for removing striae in quartz glass by heat treatment at such a high temperature is disclosed in, for example,
No. 2-158121 discloses a high purity quartz glass of 1800.
There is disclosed a method of melting at a high temperature of not less than 2 ° C. and treating at a hydrostatic pressure of not less than 2 atm. However, a device that can withstand such high temperature and pressure is inevitably bulky and expensive.
【０００４】また、特開昭６４−２８２４０号には、石
英ガラスを軟化点以上の温度に加熱して自重変形を行わ
せる操作を繰り返し行い、しかも操作毎の自重変形方向
を変えて、内部の脈理を除去する方法が開示されてい
る。この方法では、軟化点以上の成形操作を繰り返し行
う必要があり、工程が煩雑になる問題点があった。In Japanese Patent Application Laid-Open No. 64-28240, an operation of heating quartz glass to a temperature equal to or higher than the softening point and performing its own weight deformation is repeated, and the direction of its own weight deformation is changed for each operation, so that the internal A method for removing stria is disclosed. In this method, it is necessary to repeatedly perform a molding operation at a temperature equal to or higher than the softening point, and there is a problem that the process becomes complicated.
【０００５】一方近年、超ＬＳＩの製造においては、サ
ブミクロン以下のパターン解像度が要求され、フォトリ
ソグラフィーの露光光源としてより紫外光のＫｒＦエキ
シマレーザー（λ＝２４８ｎｍ）あるいはＡｒＦレーザ
ー（λ＝１９３ｎｍ）が検討されている。このように露
光光源が短波長になると、露光装置に使用される光学部
材としては、それらの波長域における透過性の問題から
商業的に応用可能な光学材料としては石英ガラスしかな
い。従って、露光装置の収差補正を不要とするために
は、石英ガラス自体の屈折率の変動を１×１０-6以下に
抑える必要がある。On the other hand, in recent years, in the manufacture of VLSI, a pattern resolution of submicron or less is required, and a KrF excimer laser (λ = 248 nm) or an ArF laser (λ = 193 nm) of ultraviolet light is used as an exposure light source for photolithography. Are being considered. As described above, when the exposure light source has a short wavelength, there is only quartz glass as a commercially applicable optical material as an optical member used in the exposure apparatus due to a problem of transparency in those wavelength ranges. Therefore, in order to eliminate the need for correcting the aberration of the exposure apparatus, it is necessary to suppress the fluctuation of the refractive index of the quartz glass itself to 1 × 10 −6 or less.
【０００６】石英ガラスの脈理が徐冷により除去された
としても、石英ガラス中に屈折率の変動を与えるような
元素が分布していれば、その元素がもたらす屈折率の変
動のために超ＬＳＩの露光装置の光学部材として使用可
能な高均質性を達成することは困難である。例えばＧ．
Ｈｅｔｈｅｒｉｎｇｔｏｎ等（１９６２）は、石英ガラ
ス中に含有されるＯＨ基量は屈折率に対して、約−１×
１０-6／１０ｐｐｍの変動をあたえることを報告してい
る。また石英ガラス中のＣｌ元素も、１×１０-6／１０
ｐｐｍ程度の屈折率変動をもたらすといわれている（Ｓ
ｕｓａ等（１９８５) ）。[0006] Even if the striae of the quartz glass are removed by slow cooling, if an element that causes a change in the refractive index is distributed in the quartz glass, the ultra-smallness of the element causes the change in the refractive index. It is difficult to achieve high homogeneity that can be used as an optical member of an LSI exposure apparatus. For example, G.
The like (1962) Hetherington, relative to OH groups amount refractive index contained in the quartz glass, about -1 ×
Have reported that give variation of 10 -6 / 10pp m. The Cl element in the quartz glass is also 1 × 10 −6 / 10
Once also the refractive index variation in pp m extent that we Stoi (S
usa et al. (1985)).
【０００７】従って、屈折率の変動が１×１０-6以下の
紫外線レーザー用石英ガラス光学部材を製造する際に
は、該石英ガラス中に含有されるＯＨ基量ならびにＣｌ
量の変動幅を無くし、石英ガラス体中のＯＨ基量ならび
にＣｌ量をあらゆるところで均一にすればよいことは容
易に推察される。ところがガラス形成原料を火炎加水分
解して多孔質ガラス体を形成した後透明ガラス化した石
英ガラスや、ガラス形成原料を火炎加水分解して石英ガ
ラスを直接基材に堆積させる方法で製造される石英ガラ
スにおいても製造時の温度分布等の影響によりＯＨ基量
を石英ガラス全域にわたって均一にすることは困難であ
った。Therefore, the fluctuation of the refractive index is 1 × 10 −6 or less.
When producing a quartz glass optical member for an ultraviolet laser, the amount of OH groups contained in the quartz glass and Cl
Eliminates the fluctuation range of the amount, yo if the OH group content and Cl content of the quartz glass body in uniformly everywhere Ikoto is easily inferred. However, quartz glass produced by flame hydrolysis of a glass-forming raw material to form a porous glass body and then vitrification, or quartz manufactured by a method of flame-hydrolyzing a glass-forming raw material and directly depositing quartz glass on a substrate. Even in glass, it was difficult to make the OH group content uniform over the entire area of quartz glass due to the influence of temperature distribution and the like during production.
【０００８】次に考えられるＯＨ基量の変動を抑える方
法としては、石英ガラス中に含有されるＯＨ基量の絶対
値を減少させることである。多孔質石英ガラス体を透明
ガラス化する方法において、該方法で製造される石英ガ
ラス中のＯＨ基量を、Ｃｌ2、ＣＣｌ4 等のハロゲン化
合物で多孔質ガラス体を処理することによって低減化す
る技術は、低伝送損失な光ファイバーを製造する手段と
して公知な技術である。しかしながら、かかる方法で作
製された石英ガラス中には、Ｃｌ元素が分布し、それが
屈折率の変動をもたらし所望の均質性を達成することが
困難であった。The next conceivable method for suppressing the fluctuation of the OH group amount is to reduce the absolute value of the OH group amount contained in the quartz glass. In a method of vitrifying a porous quartz glass body, the amount of OH groups in the quartz glass produced by the method is reduced by treating the porous glass body with a halogen compound such as Cl 2 or CCl 4. The technique is a technique known as a means for producing an optical fiber with low transmission loss. However, the Cl element is distributed in the quartz glass produced by such a method, which causes a change in the refractive index, and it is difficult to achieve a desired homogeneity.
【０００９】さらには特開平２−１０２１３９号には、
石英ガラス中のＯＨ基濃度をなめらかな凹型に分布させ
ることによって均質性を向上させる方法が開示されてい
る。この方法では、石英ガラス中に凹型のＯＨ基分布を
形成させる必要があり、熱処理条件を精密に制御する必
要があった。さらに気相反応法により多孔質石英ガラス
体を経て形成された石英ガラスについては、該石英ガラ
ス中には凸型のＯＨ基分布が形成されるため、特開平２
−１０２１３９号に開示された方法を応用することは実
質的に不可能であるという問題があった。Further, JP-A-2-102139 discloses that
A method for improving the homogeneity by distributing the OH group concentration in quartz glass in a smooth concave shape is disclosed. In this method, it is necessary to form a concave OH group distribution in the quartz glass, and it is necessary to precisely control the heat treatment conditions. Further, regarding quartz glass formed through a porous quartz glass body by a gas phase reaction method, a convex OH group distribution is formed in the quartz glass.
There is a problem that it is practically impossible to apply the method disclosed in JP-A-102139.
【００１０】[0010]
【発明が解決しようとする課題】本発明の目的は、前述
の問題点を解消し、高エネルギー密度の光を利用する光
学系に応用可能な、実質的に脈理のない紫外線レーザー
を照射して用いる石英ガラス光学部材の製造方法を提供
することにある。SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above-mentioned problems and to provide a substantially striae-free ultraviolet laser applicable to an optical system utilizing high energy density light.
To provide a method for manufacturing a quartz glass optical member to be used by irradiating the optical member .
【００１１】[0011]
【課題を解決するための手段】本発明は前述の課題を解
決すべくなされたものであり、紫外線レーザーを照射し
て用いる石英ガラス光学部材の製造方法であって、 （１）ガラス形成原料を火炎加水分解して形成される石
英ガラス微粒子を基材に堆積・成長させて多孔質石英ガ
ラス体を形成する工程、 （２）前記多孔質石英ガラス体を非塩素低水蒸気分圧雰
囲気下において、透明ガラス化温度以下の温度域で一定
時間保持し加熱処理してＯＨ基含有量を低減す る工程、 （３）前記加熱処理された多孔質石英ガラス体を、透明
ガラス化温度まで昇温・透明ガラス化して石英ガラス体
を得る工程、 （４）前記石英ガラス体を軟化点以上の温度に加熱して
成形し、成形石英ガラス体を得る工程、及び、 （５）前記成形石英ガラス体を、少なくとも１１００〜
１２００℃の温度域では４０℃／時間以下の冷却速度と
なるように徐冷する工程、を備えることを特徴とする石
英ガラス光学部材の製造方法 を提供するものである。DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is directed to irradiating an ultraviolet laser.
Stone A method for manufacturing a silica glass optical member, which is formed by flame hydrolysis of (1) a glass forming raw material used Te
Porous quartz particles are deposited and grown on a substrate
(2) forming the porous quartz glass body in a non-chlorine low steam partial pressure atmosphere;
Under ambient temperature, constant in the temperature range below the vitrification temperature
Step it reduces the OH group content and heat treatment time retaining the (3) the heat-treated porous silica glass body, a transparent
Heated to the vitrification temperature and turned into a transparent vitrified quartz glass body
The step of obtaining, (4) heating the quartz glass body to a temperature above the softening point
Shaping to obtain a shaped quartz glass body, and (5) forming the shaped quartz glass body at least 1100 to
In a temperature range of 1200 ° C, a cooling rate of 40 ° C / hour or less
Characterized by comprising a step of gradually cooling to become
An object of the present invention is to provide a method for manufacturing an English glass optical member .
【００１２】また本発明は、前記透明ガラス化温度以下
の温度域で一定時間保持し加熱処理する工程において、
雰囲気の露点温度が−７０℃以下であることを特徴とす
る前記の石英ガラス光学部材の製造方法を提供するもの
である。[0012] The present invention also relates to the transparent vitrification temperature or lower.
In the step of holding and heating at a temperature range of a certain time,
The dew point temperature of the atmosphere is -70 ° C or less.
The present invention also provides a method for producing the above quartz glass optical member .
【００１３】また本発明は、前記透明ガラス化温度以下
の温度域が８００〜１２５０℃であることを特徴とする
前記の石英ガラス光学部材の製造方法を提供するもので
ある。[0013] The present invention also relates to the transparent vitrification temperature or lower.
Characterized by a temperature range of 800 to 1250 ° C.
An object of the present invention is to provide a method of manufacturing the above quartz glass optical member .
【００１４】本発明において、予めガラス形成原料を火
炎加水分解して得られる石英ガラス微粒子を基材に堆積
・成長させた多孔質石英ガラス体を透明ガラス化する温
度以下の温度域で水蒸気分圧の低い雰囲気中に一定時間
加熱保持した後、透明ガラス化温度に昇温加熱して透明
ガラス化して石英ガラス体とする。In the present invention, the partial pressure of water vapor is set at a temperature not higher than the temperature at which a porous quartz glass body obtained by previously depositing and growing quartz glass fine particles obtained by flame hydrolysis of a glass forming raw material on a substrate is turned into a transparent glass. After heating for a certain period of time in an atmosphere having a low temperature, the glass is heated to a transparent vitrification temperature and heated to form a transparent glass to form a quartz glass body.
【００１５】用いられるガラス形成原料としては、ガス
化可能な原料であれば特に制限されるものではないが、
ＳｉＣｌ4 、ＳｉＨＣｌ3 、ＳｉＨ2 Ｃｌ2 、Ｓｉ（Ｃ
Ｈ3）Ｃｌ3 等の塩化物、ＳｉＦ4 、ＳｉＨＦ3 ，Ｓｉ
Ｈ2 Ｆ2 等のフッ化物、ＳｉＢｒ4 、ＳｉＨＢｒ3 等の
臭化物、ＳｉＩ4 の沃化物などのハロゲン化珪素化合物
が作業性やコストの面から好ましい。多孔質石英ガラス
体は、これらのガラス形成原料を通常の酸水素火炎中で
加水分解し、生じた石英ガラス微粒子を基材上に堆積さ
せて形成される。The glass forming raw material used is not particularly limited as long as it is a gasizable raw material.
SiCl 4 , SiHCl 3 , SiH 2 Cl 2 , Si (C
H 3 ) chlorides such as Cl 3 , SiF 4 , SiHF 3 , Si
Silicon halides such as fluorides such as H 2 F 2 , bromides such as SiBr 4 and SiHBr 3 , and iodides of SiI 4 are preferred in terms of workability and cost. The porous quartz glass body is formed by hydrolyzing these glass forming raw materials in a normal oxyhydrogen flame and depositing the resulting quartz glass fine particles on a substrate.
【００１６】このようにして得られた多孔質石英ガラス
体は、ついで非塩素低水蒸気分圧雰囲気下で一定時間加
熱保持されてＯＨ基含有量を低減した後、透明ガラス化
温度まで昇温されて透明ガラス化して石英ガラスとな
る。 The porous quartz glass body thus obtained is heated and held for a certain period of time in a non-chlorine low-vapor partial pressure atmosphere to reduce the OH group content , and then heated to a transparent vitrification temperature. It becomes transparent glass and becomes quartz glass .
【００１７】すなわち、例えば、多孔質体は雰囲気制御
可能な電気炉内に予め装着された後、一定の昇温速度で
加熱される。ついで所定の温度に到達の後、乾燥ガスを
雰囲気中に導入し、多孔質体が接する雰囲気を置換する
ことにより雰囲気中の水蒸気分圧を所定値以下に低減す
る。その水蒸気分圧としては、０．００２ｍｍＨｇ以下
であることが好ましく、これより大きい場合には最終的
に得られる石英ガラス中のＯＨ基量を低減させることが
困難な場合がある。この水蒸気分圧０．００２ｍｍＨｇ
以下は、露点温度が−７０℃以下であることと同等であ
る。That is, for example, after the porous body is previously mounted in an electric furnace whose atmosphere can be controlled, it is heated at a constant heating rate . One Ide After reaching a predetermined temperature, a dried gas is introduced into the atmosphere, reducing the partial pressure of water vapor in the atmosphere below a predetermined value by substituting the atmosphere porous body contact. As the water vapor partial pressure, it may preferably, when it is difficult to reduce the OH groups of the silica glass finally obtained when this is greater than or less 0.002MmHg. This partial pressure of steam is 0.002mmHg
The following is equivalent to the dew point temperature being −70 ° C. or less.
【００１８】また加熱保持する温度域としては、８００
〜１２５０℃の範囲内が好ましく、この温度域より低い
温度では実質的な効果が得られず、またこの温度域を超
えた温度では多孔質体の表面のガラス化が進行するた
め、多孔質体内部を所望の低水蒸気分圧雰囲気に置換す
ることができないおそれがある。また、この温度域であ
れば、加熱処理の方法としては、一定温度に保持しても
よく、またこの温度域内を所定の時間の範囲内で昇温さ
せながら処理してもよい。またこの温度域での保持時間
は、保持温度に依存するため一概に規定することはでき
ないが１〜３０時間程度の範囲から選ぶことが好まし
く、これより短時間の場合には実質的な効果が得られな
いおそれがあり、またこれより長時間かけた場合にもそ
の効果は変わらないために生産効率等を低下させるおそ
れがある。また、乾燥ガスとしては窒素、ヘリウム、ア
ルゴン等を通常用いることができるが、乾燥ガスとして
使用できれば必ずしもこれらのガスに限定されるもので
はない。The heating temperature range is 800
The temperature is preferably in the range of from 1250 ° C. to below 1250 ° C. Substantial effects cannot be obtained at a temperature lower than this temperature range, and vitrification of the surface of the porous body proceeds at a temperature exceeding this temperature range. There is a possibility that the inside can not be replaced with a desired low steam partial pressure atmosphere. In addition, in this temperature range, the heating method may be maintained at a constant temperature.
Rather good, also be treated while warming the temperature range within a predetermined time has good. Further, the holding time in this temperature range depends on the holding temperature and cannot be specified unconditionally, but is preferably selected from a range of about 1 to 30 hours. Don't get
Io has it also late also lowers the production efficiency and the like to the effect does not change when subjected longer than this
There is . In addition, as a dry gas, nitrogen, helium, argon, or the like can be generally used, but is not necessarily limited to these gases as long as it can be used as a dry gas.
【００１９】次いでこのような加熱処理の後、多孔質ガ
ラス体はガラス化温度まで昇温されてガラス化される。
ガラス化温度としては、１３５０〜１５００℃の範囲か
ら選ぶことが好ましい。更に、加熱処理とガラス化処理
は、それぞれ別の加熱装置で行われてもよいが、その場
合には、移送時に水分が吸着したりすることを防止する
等の処置を講じることが好ましい。したがって、さらに
好ましい実施態様としては、加熱処理とガラス化を同一
の設備で行うことが好ましい。Next, after such a heat treatment, the porous glass body is heated to a vitrification temperature and vitrified.
The vitrification temperature is preferably selected from the range of 1350 to 1500 ° C. Further, heat treatment and vitrification process, it may also be carried out in separate heating devices bur, in that case, it is preferable to take measures such as water at the time of transfer to prevent or adsorption. Therefore, as a more preferred embodiment, it is preferable to perform the heat treatment and the vitrification in the same facility.
【００２０】こうして得られた石英ガラス体を軟化点以
上の温度に加熱し、所望の形状に成形加工を行い光学用
石英ガラス部材を製造する。成形加工の温度域は、１６
５０〜１８００℃の範囲から選択することが好ましい。
１６５０℃より低い温度では石英ガラスの粘度が高いた
め実質的に自重変形が行われず、またＳｉＯ2 の結晶相
であるクリストバライトの成長がおこりいわゆる失透が
生じるおそれがある。また１８００℃より高い温度で
は、ＳｉＯ2 の昇華が無視できなくなるおそれがある。
また、石英ガラス体の自重変形を行わせる方向は、特に
規定されないが多孔質ガラス体の成長方向と同一である
ことが好ましい。The quartz glass body thus obtained is heated to a temperature equal to or higher than the softening point and formed into a desired shape to produce an optical quartz glass member. The temperature range of the forming process is 16
It is preferable to select from the range of 50 to 1800 ° C.
1650 ° C. substantially self-weight deformation is not performed due to the high viscosity of the quartz glass at lower temperatures, also the growth of cristobalite which is a crystal phase of SiO 2 takes place there is a possibility that the so-called devitrification occurs. In addition a temperature higher than 1800 ° C., sublimation of SiO 2 there is a not negligible Ruosore.
The direction in which the quartz glass body undergoes its own weight deformation is not particularly limited, but is preferably the same as the growth direction of the porous glass body.
【００２１】さらにこうして得られた成形石英ガラス体
を石英ガラスの徐冷点近傍の温度域で徐冷して、光学用
石英ガラス部材を製造する。石英ガラスの徐冷時の冷却
速度は大きさにもよるが、石英ガラスの徐冷点はおおむ
ね１１００℃であるので、少なくとも１１００〜１２０
０℃の温度域では、４０℃／時間以下にする。４０℃／
時間を超えると、成形ガラス体外周部における屈折率の
変動幅が大きくなり、結果として本発明の目的とする屈
折率の変動幅が１×１０-6以下となる領域が成形ガラス
体中央部にほぼ限られ、光学用石英ガラスの製品歩留ま
りを著しく低下させる。 Further, the shaped quartz glass body thus obtained is gradually cooled in a temperature range near the annealing point of the quartz glass to produce an optical quartz glass member. Although the cooling rate during the slow cooling of quartz glass depends on the size, the slow cooling point of quartz glass is roughly
1100 ° C, so at least 1100-120
0 The temperature range of ° C., to less than 40 ° C. / hour. 40 ℃ /
When the time is exceeded, the fluctuation range of the refractive index in the outer peripheral portion of the formed glass body becomes large, and as a result, the region where the fluctuation range of the refractive index aimed at by the present invention becomes 1 × 10 −6 or less is located in the center portion of the formed glass body. Almost limited, it significantly reduces the product yield of optical quartz glass .
【００２２】以上のような工程を経て得られる石英ガラ
スは、石英ガラス中に含有されるＯＨ基量が１００ｐｐ
ｍ以下となり、該ガラス中のＯＨ基量の変動幅はほとん
どの領域において±５ｐｐｍ以内であり均質性に優れる
石英ガラスである。また、本発明により製造される石英
ガラスは、ガラス形成原料として高純度な合成原料が使
用可能なこと、溶融工程を経ないためルツボ等からの不
純物の混入がないこと等から、鉄、ニッケル等の重金属
元素やナトリウム、カリウム等のアルカリ金属元素の不
純物総量が１ｐｐｍ以下と極めて高純度であり、ＫｒＦ
レーザーやＡｒＦレーザー等の紫外線に対しても蛍光発
光やソーラリゼーション等を生じず、耐紫外線性にも優
れている。The quartz glass obtained through the above steps has an OH group content of 100 pp in the quartz glass.
m or less, and the fluctuation range of the OH group content in the glass is within ± 5 ppm in most regions, and it is a quartz glass excellent in homogeneity. In addition, the quartz glass produced according to the present invention is made of iron, nickel, etc., because a high-purity synthetic raw material can be used as a glass forming raw material, and there is no impurity from a crucible or the like because it does not go through a melting step. The total amount of impurities of heavy metal elements and alkali metal elements such as sodium, potassium and the like is extremely high as 1 ppm or less, and KrF
It does not generate fluorescence or solarization even with ultraviolet rays such as a laser or an ArF laser, and has excellent ultraviolet resistance.
【００２３】[0023]
【作用】本発明の方法により、ガラス形成原料を火炎加
水分解させて形成される多孔質石英ガラス体を透明ガラ
ス化して得られる合成石英ガラス中のＯＨ基量が低減さ
れる機構は、必ずしも明確ではないが、低露点温度のガ
ス雰囲気で透明ガラス化以前に熱処理することによっ
て、多孔質石英ガラス中のシラノール基が遊離してしま
うものと考えられる。The mechanism by which the amount of OH groups in the synthetic quartz glass obtained by subjecting the porous quartz glass body formed by flame hydrolysis of the raw material for forming a glass to a transparent vitrification by the method of the present invention is not necessarily clear. but not by heat treatment to the transparent vitrification earlier gas atmosphere of low dew point temperature, the silanol groups of porous silica glass is it is thought shall become liberated.
【００２４】ガラス形成原料を火炎加水分解させて形成
される多孔質石英ガラス体を透明ガラス化して得られる
合成石英ガラス体から製造される合成石英ガラスブロッ
クは、多孔質石英ガラス体の成長面内においてＯＨ基量
の分布幅が大きく、該合成石英ガラスブロックの多孔質
石英ガラス体の成長面内において屈折率の変動をもたら
し、高均質な合成石英ガラス体を得ることが困難であっ
た。しかしながら、本発明の方法によれば、合成石英ガ
ラス体中のＯＨ基量の絶対値を低減させることによっ
て、変動幅を抑え、ＯＨ基の変動に基づく屈折率の揺ら
ぎを抑えることが可能になったと推察される。しかも本
発明の方法は、ＯＨ基量の低減化の方法として従来より
公知のハロゲン化物を使用しないため、公知の方法では
石英ガラス中に残留するハロゲンの影響が全く無く、高
均質性が達成されたものと思われる。A synthetic quartz glass block produced from a synthetic quartz glass body obtained by transforming a porous quartz glass body formed by flame hydrolysis of a glass-forming raw material into a transparent quartz glass body is formed within the growth surface of the porous quartz glass body. In this method, the distribution width of the OH group content was large, and the refractive index fluctuated within the growth surface of the porous quartz glass body of the synthetic quartz glass block, making it difficult to obtain a highly homogeneous synthetic quartz glass body. However, according to the method of the present invention, by reducing the absolute value of the OH groups of the synthetic quartz glass body in, e suppress the fluctuation range, it is possible to obtain suppress the fluctuation of the refractive index based on the fluctuation of the OH group It is presumed that it became. In addition, the method of the present invention does not use a conventionally known halide as a method for reducing the amount of OH groups , so that the known method has no effect of halogen remaining in quartz glass and achieves high homogeneity. It seems to have been.
【００２５】[0025]
【実施例】以下、本発明の詳細についてさらに実施例に
より説明するが、本発明は当然のことながらこれら実施
例により限定されるものではない。 実施例１ 公知の方法により、ＳｉＣｌ4 を酸水素火炎中で加熱加
水分解させて形成された直径３５ｃｍ，長さ１００ｃｍ
の多孔質石英ガラス体を室温で雰囲気制御可能な電気炉
内に設置した。ついで露点温度−７０℃の窒素ガスで電
気炉内雰囲気を置換した後、露点温度−７０℃の窒素ガ
スを流しながら５００℃／時間の昇温速度で１０００℃
まで昇温した。引き続き昇温速度を５０℃／時間とし、
１２５０℃まで昇温して、その温度で５時間保持した。EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but it should be understood that the present invention is not limited to these Examples. Example 1 By a known method, SiCl 4 was heated and hydrolyzed in an oxyhydrogen flame to form a diameter of 35 cm and a length of 100 cm.
Was placed in an electric furnace capable of controlling the atmosphere at room temperature. Then, after replacing the atmosphere in the electric furnace with a nitrogen gas having a dew point temperature of -70 ° C, the nitrogen gas having a dew point temperature of -70 ° C was flowed at a temperature rising rate of 500 ° C / hour at 1000 ° C.
Temperature. Continue the rate of temperature increase and 50 ℃ / time,
The temperature was raised to 1250 ° C. and maintained at that temperature for 5 hours .
【００２６】こうして得られた熱処理済みの多孔質石英
ガラス体を透明ガラス化のための炉内最高温度が１４５
０℃に制御された電気炉内上部に設置し、炉内を露点温
度が−７０℃のヘリウムガスで置換した後、８０ｃｍ／
時間の速度で下降させながら最高温度域を通過させて透
明ガラス化を行った。こうして得られた透明石英ガラス
を、カーボン製発熱体を有する電気炉内で、軟化点以上
の１７５０℃に加熱して自重変形を行わせ、２５０×２
５０×１２０ｍｍのブロック形状に成形した。引き続
き、電気炉内に成形ブロックをセットしたまま電気炉の
温度を１２００℃まで降温させ、以後３０℃／時間の冷
却速度で徐冷を行い、炉内温度が１０００℃になったと
ころで給電を停止し炉内放冷した。The thus obtained heat-treated porous quartz glass body has a maximum furnace temperature of 145 for clear vitrification.
It was installed in the upper part of an electric furnace controlled at 0 ° C., and the inside of the furnace was replaced with helium gas having a dew point temperature of −70 ° C., and then 80 cm /
The glass was passed through the highest temperature range while being lowered at the speed of time , and vitrification was performed. The transparent quartz glass thus obtained is heated to 1750 ° C. above the softening point in an electric furnace having a heating element made of carbon and deformed under its own weight.
It was formed into a block shape of 50 × 120 mm. Subsequently, the temperature remains the electric furnace was set forming blocks in an electric furnace is lowered to 1200 ° C., subjected to slow cooling at a cooling rate of subsequent 30 ° C. / time, stop the feeding at the furnace temperature reached 1000 ° C. The furnace was allowed to cool.
【００２７】こうして得られた石英ガラスブロックの１
２０ｍｍ方向の中心部より、２５０×２５０×５７ｍｍ
の石英ガラスブロックを切り出し、その中心部２２０ｍ
ｍφの内部および外部について精密干渉計（ＺｙｇｏI
V）により屈折率分布を評価した。またＯＨ基量分布
は、２５０×２５０×１２０ｍｍ石英ガラスブロックよ
り屈折率分布を評価した部分のすぐ隣の場所より、２ｍ
ｍ厚みのガラス板を切り出し日本分光社製簡易ＦＴＩＲ
装置により３７００ｃｍ-1の吸収により定量した。Ｃｌ
含有量は得られた石英ガラスをアルカリ溶融したのち、
イオンクロマトグラフィー法により定量した。結果を表
１に示す。The thus obtained quartz glass block 1
250 x 250 x 57 mm from the center in the 20 mm direction
Cut out a quartz glass block of 220m
precision interferometer (ZygoI
V) was used to evaluate the refractive index distribution. The OH group distribution was 2 m from the place immediately adjacent to the portion where the refractive index distribution was evaluated from the 250 × 250 × 120 mm quartz glass block.
Cut out a glass plate of m thickness and make a simple FTIR manufactured by JASCO
It was quantified by absorption at 3700 cm -1 by the apparatus. Cl
After alkali melting the obtained quartz glass, the content is
It was quantified by ion chromatography. Table 1 shows the results.
【００２８】比較例１ １２５０℃での熱処理を行わない他は、実施例１と同一
の方法で作製した石英ガラスブロックの中心部２２０ｍ
ｍφの屈折率変動幅、ＯＨ基量及びその分布幅、Ｃｌ含
有量を表１に示す。[0028] except that no heat treatment is performed in Comparative Example 1 1250 ° C., the center portion of the silica glass block was produced in the same manner as in Example 1 220 m
Table 1 shows the refractive index fluctuation width of mφ, the OH group amount and its distribution width, and the Cl content.
【００２９】比較例２ 徐冷工程の冷却速度を８０℃／時間とした以外は、実施
例１と同一の方法で作製した石英ガラスブロックの外周
部の屈折率変動幅を表１に示す。[0029] except that the Comparative Example 2 annealing step 80 ° C. / time the cooling rate of, the refractive index variation width of the outer peripheral portion of the silica glass block was produced in the same manner as in Example 1 in Table 1.
【００３０】[0030]
【表１】 [Table 1]
【００３１】[0031]
【発明の効果】本発明の方法によれば、石英ガラス中に
Ｃｌ元素などの不純物の残存を生じさせることなくＯＨ
基量を低減させることが可能であり、それに基づく屈折
率の揺らぎを抑止せしめ、石英ガラスの屈折率変動幅を
１×１０-6以下にして均質性を向上することが可能であ
る。これにより高エネルギー密度の光を利用する光学系
に応用できる、実質的に脈理のない光学用石英ガラス部
材が得られる。According to the method of the present invention, OH can be produced without leaving impurities such as Cl element in quartz glass.
It is possible to reduce the amount of base , suppress fluctuation of the refractive index based on the base amount, and improve the homogeneity by setting the fluctuation range of the refractive index of quartz glass to 1 × 10 −6 or less. As a result, an optical quartz glass member having substantially no striae, which can be applied to an optical system utilizing light of high energy density, is obtained.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.6，ＤＢ名) C03B 20/00 C03B 8/04──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. 6 , DB name) C03B 20/00 C03B 8/04
Claims (6)
ス光学部材の製造方法であって、 （１）ガラス形成原料を火炎加水分解して形成される石
英ガラス微粒子を基材に堆積・成長させて多孔質石英ガ
ラス体を形成する工程、 （２）前記多孔質石英ガラス体を非塩素低水蒸気分圧雰
囲気下において、透明ガラス化温度以下の温度域で一定
時間保持し加熱処理してＯＨ基含有量を低減する工程、 （３）前記加熱処理された多孔質石英ガラス体を、透明
ガラス化温度まで昇温・透明ガラス化して石英ガラス体
を得る工程、 （４）前記石英ガラス体を軟化点以上の温度に加熱して
成形し、成形石英ガラス体を得る工程、及び、 （５）前記成形石英ガラス体を、少なくとも１１００〜
１２００℃の温度域では４０℃／時間以下の冷却速度と
なるように徐冷する工程、 を備える ことを特徴とする石英ガラス光学部材の製造方
法。1. Quartz glass used by irradiating an ultraviolet laser
A manufacturing method of the scan optical member (1) a glass-forming raw material quartz glass particles are formed by flame hydrolysis were deposited and grown on a substrate to form a porous quartz glass body, (2) The porous quartz glass body is placed in a non-chlorine low steam partial pressure atmosphere.
A step of reducing the OH group content by holding and heating at a temperature range not higher than the transparent vitrification temperature for a certain period of time under ambient atmosphere , (3) bringing the heat-treated porous quartz glass body to a transparent vitrification temperature (4) heating the quartz glass body to a temperature equal to or higher than its softening point,
Shaping to obtain a shaped quartz glass body, and (5) forming the shaped quartz glass body at least 1100 to
In a temperature range of 1200 ° C, a cooling rate of 40 ° C / hour or less
Method for manufacturing a silica glass optical member, characterized in that it comprises so as to step of slow cooling, the.
時間保持し加熱処理する工程において、雰囲気の露点温
度が−７０℃以下であることを特徴とする請求項１記載
の石英ガラス光学部材の製造方法。2. A process for the holding vitrification temperature below the temperature range at a predetermined time to heat treatment, a quartz glass optical member according to claim 1, wherein the dew-point temperature of the atmosphere is -70 ° C. or less Manufacturing method.
０〜１２５０℃であることを特徴とする請求項１または
２記載の石英ガラス光学部材の製造方法。3. The temperature range below the transparent vitrification temperature is 80.
Claim characterized in that it is a 0 to 1,250 ° C. 1 or
3. The method for producing a quartz glass optical member according to item 2 .
する時間が１〜３０時間であることを特徴とする請求項
１、２または３記載の石英ガラス光学部材の製造方法。4. The method according to claim 1, wherein the holding time in the temperature range below the transparent vitrification temperature is 1 to 30 hours.
4. The method for producing a quartz glass optical member according to 1, 2, or 3 .
量が１０ｐｐｍ以下、ＯＨ基含有量 が１００ｐｐｍ以下
である請求項１、２、３または４記載の石英ガラス光学
部材の製造方法。 5. The manufactured quartz glass optical member contains Cl.
The amount is 10 ppm or less, and the OH group content is 100 ppm or less.
The quartz glass optic according to claim 1, 2, 3, or 4,
Manufacturing method of the member.
とも１方向について直径２２０ｍｍの円形で囲まれる領
域にわたって屈折率の変動幅が１×１０ -6 以下である請
求項１、２、３、４または５記載の石英ガラス光学部材
の製造方法。 6. The manufactured quartz glass optical member has a small number.
Both areas are enclosed by a circle with a diameter of 220 mm in one direction.
That the fluctuation range of the refractive index over the region is 1 × 10 -6 or less
6. The quartz glass optical member according to claim 1, 2, 3, 4, or 5.
Manufacturing method.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20748691A JP2861512B2 (en) | 1991-07-24 | 1991-07-24 | Manufacturing method of quartz glass optical member |
| US07/912,776 US5330941A (en) | 1991-07-24 | 1992-07-13 | Quartz glass substrate for polysilicon thin film transistor liquid crystal display |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20748691A JP2861512B2 (en) | 1991-07-24 | 1991-07-24 | Manufacturing method of quartz glass optical member |
Related Child Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10091875A Division JP2862001B2 (en) | 1998-04-03 | 1998-04-03 | Manufacturing method of quartz glass optical member |
| JP9187698A Division JPH10324528A (en) | 1998-04-03 | 1998-04-03 | Optical quartz glass |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0524856A JPH0524856A (en) | 1993-02-02 |
| JP2861512B2 true JP2861512B2 (en) | 1999-02-24 |
Family
ID=16540536
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20748691A Expired - Lifetime JP2861512B2 (en) | 1991-07-24 | 1991-07-24 | Manufacturing method of quartz glass optical member |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2861512B2 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004065315A1 (en) * | 2003-01-21 | 2004-08-05 | Nikon Corporation | Synthetic quartz glass optical member and method for preparation thereof |
| US11952303B2 (en) | 2015-12-18 | 2024-04-09 | Heraeus Quarzglas Gmbh & Co. Kg | Increase in silicon content in the preparation of quartz glass |
| JP7044454B2 (en) | 2015-12-18 | 2022-03-30 | ヘレウス クワルツグラス ゲーエムベーハー ウント コンパニー カーゲー | Preparation of carbon-doped silicon dioxide granules as an intermediate in the preparation of quartz glass |
| TW201731782A (en) | 2015-12-18 | 2017-09-16 | 何瑞斯廓格拉斯公司 | Preparation of a quartz glass body in a multi-chamber oven |
| EP3390304B1 (en) | 2015-12-18 | 2023-09-13 | Heraeus Quarzglas GmbH & Co. KG | Spray granulation of silicon dioxide in the production of quartz glass |
| KR20180095622A (en) | 2015-12-18 | 2018-08-27 | 헤래우스 크바르츠글라스 게엠베하 ＆ 컴파니 케이지 | Manufacture of Silica Glass Products from Molten Crucibles Made of Refractory Metals |
| JP6881776B2 (en) | 2015-12-18 | 2021-06-02 | ヘレウス クワルツグラス ゲーエムベーハー ウント コンパニー カーゲー | Preparation of opaque quartz glass body |
| KR20180095616A (en) * | 2015-12-18 | 2018-08-27 | 헤래우스 크바르츠글라스 게엠베하 ＆ 컴파니 케이지 | Preparation of silica glass body using dew point control in melting furnace |
| KR20180094087A (en) | 2015-12-18 | 2018-08-22 | 헤래우스 크바르츠글라스 게엠베하 ＆ 컴파니 케이지 | Preparation of Silica Glass Products from Silica Granules |
| CN113387550A (en) * | 2021-07-03 | 2021-09-14 | 四川神光石英科技有限公司 | Method for improving uniformity of quartz glass |
-
1991
- 1991-07-24 JP JP20748691A patent/JP2861512B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0524856A (en) | 1993-02-02 |
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