JP5486774B2 - Synthetic quartz glass - Google Patents
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- JP5486774B2 JP5486774B2 JP2008036611A JP2008036611A JP5486774B2 JP 5486774 B2 JP5486774 B2 JP 5486774B2 JP 2008036611 A JP2008036611 A JP 2008036611A JP 2008036611 A JP2008036611 A JP 2008036611A JP 5486774 B2 JP5486774 B2 JP 5486774B2
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 title claims description 185
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 148
- 125000002887 hydroxy group Chemical group [H]O* 0.000 claims description 35
- 238000009826 distribution Methods 0.000 claims description 33
- 230000003287 optical effect Effects 0.000 claims description 19
- 238000000611 regression analysis Methods 0.000 claims description 13
- 239000001257 hydrogen Substances 0.000 description 87
- 229910052739 hydrogen Inorganic materials 0.000 description 87
- 238000010438 heat treatment Methods 0.000 description 27
- 238000004519 manufacturing process Methods 0.000 description 20
- 238000005259 measurement Methods 0.000 description 20
- 239000004071 soot Substances 0.000 description 15
- 238000012545 processing Methods 0.000 description 14
- 238000000034 method Methods 0.000 description 11
- 239000000377 silicon dioxide Substances 0.000 description 9
- 238000012937 correction Methods 0.000 description 8
- 230000007062 hydrolysis Effects 0.000 description 8
- 238000006460 hydrolysis reaction Methods 0.000 description 8
- VXEGSRKPIUDPQT-UHFFFAOYSA-N 4-[4-(4-methoxyphenyl)piperazin-1-yl]aniline Chemical compound C1=CC(OC)=CC=C1N1CCN(C=2C=CC(N)=CC=2)CC1 VXEGSRKPIUDPQT-UHFFFAOYSA-N 0.000 description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- 238000001816 cooling Methods 0.000 description 7
- 238000000151 deposition Methods 0.000 description 7
- 229910002804 graphite Inorganic materials 0.000 description 7
- 239000010439 graphite Substances 0.000 description 7
- 239000005049 silicon tetrachloride Substances 0.000 description 7
- 238000009792 diffusion process Methods 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 238000010521 absorption reaction Methods 0.000 description 3
- 230000002411 adverse Effects 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000004017 vitrification Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000001069 Raman spectroscopy Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 238000004904 shortening Methods 0.000 description 2
- 239000003570 air Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- -1 described above Chemical compound 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000005350 fused silica glass Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000005816 glass manufacturing process Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000004556 laser interferometry Methods 0.000 description 1
- 238000001459 lithography Methods 0.000 description 1
- 238000004949 mass spectrometry Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000002829 reductive effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000010189 synthetic method Methods 0.000 description 1
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Classifications
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B19/00—Other methods of shaping glass
- C03B19/14—Other methods of shaping glass by gas- or vapour- phase reaction processes
- C03B19/1453—Thermal after-treatment of the shaped article, e.g. dehydrating, consolidating, sintering
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2201/00—Type of glass produced
- C03B2201/06—Doped silica-based glasses
- C03B2201/20—Doped silica-based glasses doped with non-metals other than boron or fluorine
- C03B2201/21—Doped silica-based glasses doped with non-metals other than boron or fluorine doped with molecular hydrogen
-
- 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
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Manufacturing & Machinery (AREA)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
- Glass Melting And Manufacturing (AREA)
- Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
Description
本発明は、合成石英ガラス体及びその製造方法に関し、より詳しくは、水素分子を含有する合成石英ガラス体及びその製造方法に関する。 The present invention relates to a synthetic quartz glass body and a method for producing the same, and more particularly to a synthetic quartz glass body containing hydrogen molecules and a method for producing the same.
フォトマスク上のパターンを、紫外光を用いてウエハー上に転写する光リソグラフィー技術は、他の電子ビームやX線を用いる技術に比較してコスト、スループットなどの面で優れていることから、半導体集積回路を製造するための露光装置用に広く用いられている。 The optical lithography technology that transfers the pattern on the photomask onto the wafer using ultraviolet light is superior in terms of cost, throughput, etc. compared to other technologies that use electron beams or X-rays. It is widely used for an exposure apparatus for manufacturing an integrated circuit.
近年、LSIの微細化、高集積化に伴い、露光用の光源の短波長化が進んでおり、従来のg線(波長436nm)やi線(波長365nm)、あるいはKrFエキシマレーザー(波長248.3nm)を経て、最近ではArFエキシマレーザー(波長193.4nm)が使用されるようになってきた。そして、このArFエキシマレーザーリソグラフィー装置に用いられる光学部材には、従来以上に透過性、均質性、複屈折、および耐レーザー性等に対する要求が厳しくなってきている。 In recent years, with the miniaturization and high integration of LSIs, the wavelength of light sources for exposure has been shortened. Conventional g-line (wavelength 436 nm), i-line (wavelength 365 nm), or KrF excimer laser (wavelength 248. 3 nm), ArF excimer laser (wavelength 193.4 nm) has recently been used. And the optical member used for this ArF excimer laser lithography apparatus has stricter requirements for transparency, homogeneity, birefringence, laser resistance and the like than before.
これらの要求に適合する光学部材の材料として、高純度の合成石英ガラスが用いられてきており、製造条件の最適化によって光学特性の改良が進められている。特に耐レーザー性の向上には合成石英ガラスに水素分子を含有させることが有効であることが知られており、石英ガラスの製造工程中において、石英ガラス内部に水素分子をドープ(添加、導入)させる処置が行われてきた。 High-purity synthetic quartz glass has been used as a material for optical members that meet these requirements, and improvements in optical properties are being promoted by optimizing manufacturing conditions. In particular, it is known that synthetic quartz glass contains hydrogen molecules to improve laser resistance. During the quartz glass manufacturing process, hydrogen molecules are doped into silica glass (addition and introduction). The treatment to be done has been performed.
石英ガラス中の水素分子の拡散には温度が大きく影響している。
例えば500℃以上の高温になると拡散が容易になるため水素分子を含有させるための時間が短くて済み、生産性の点で有利である。しかしながら、高温で水素分子が導入されると石英ガラス中に還元性欠陥が生じ、エキシマレーザーが照射されることで紫外領域に吸収が誘起される。この誘起される吸収はE’(イープライム)センターと呼ばれる常時性欠陥によるものであり、中心波長が210〜215nmの吸収帯を有し、耐レーザー性を大きく低下させてしまう。このため水素分子の導入(以下、単に水素ドープと呼ぶことがある)はできるだけ低い温度で行う必要があるが、例えば500℃未満のような低温では水素分子の石英ガラス中での拡散速度が低下するため、水素分子の導入に要する時間(以下、単に水素ドープ時間と呼ぶことがある)が非常に長くなり、生産性を悪化させてしまうという問題があった。
Temperature greatly affects the diffusion of hydrogen molecules in quartz glass.
For example, when the temperature is higher than 500 ° C., diffusion becomes easy, so that the time for containing hydrogen molecules is short, which is advantageous in terms of productivity. However, when hydrogen molecules are introduced at a high temperature, reductive defects are produced in the quartz glass, and absorption is induced in the ultraviolet region when irradiated with an excimer laser. This induced absorption is due to a permanent defect called an E ′ (e-prime) center, has an absorption band with a center wavelength of 210 to 215 nm, and greatly reduces laser resistance. For this reason, introduction of hydrogen molecules (hereinafter sometimes simply referred to as hydrogen doping) must be performed at a temperature as low as possible, but the diffusion rate of hydrogen molecules in quartz glass decreases at a low temperature, for example, below 500 ° C. Therefore, there is a problem that the time required for introducing hydrogen molecules (hereinafter, simply referred to as hydrogen doping time) becomes very long and the productivity is deteriorated.
また、これまでの研究から水素分子は屈折率の均質性に影響を及ぼすことがわかってきており、水素分子を均一にドープすることが重要であることもわかってきている。低温で、かつ均一に水素分子をドープするためには極めて長い時間が必要とされることもあって、その手法については従来から研究が進められてきた。例えば特許文献1では、合成石英ガラス体を所定の圧力の水素含有雰囲気中で熱処理する際に、水素含有ガスの圧力を連続的あるいは段階的に変化させることが記載されている。この方法の目的の一つは水素分子を石英ガラス体中にできるだけ均一に含有させることであり、平均水素濃度と水素濃度の最大値と最小値の差について検討が行われている。また特許文献2では、平均水素濃度の範囲とともに、最大値と最小値の比を規定し、屈折率の均質性に影響を及ぼさない範囲で、できるだけ短時間で水素分子のドープを行うための検討がなされている。
In addition, it has been found from previous studies that hydrogen molecules affect the homogeneity of the refractive index, and it has also been found that it is important to uniformly dope hydrogen molecules. In order to dope hydrogen molecules uniformly at a low temperature, a very long time may be required, and research has been conducted on the technique. For example,
しかしながら、このように石英ガラス体中の水素分子濃度の最大値と最小値を所定の範囲に収めるようにしたとしても、屈折率の均質性に悪影響を及ぼすことがあるという問題があった。
また、耐レーザー性を悪化させないような比較的低温下で、なおかつ生産性を阻害しない時間内で水素分子濃度を所定の範囲内に納めるようにするのは困難であるという問題があった。
However, there is a problem that even if the maximum value and the minimum value of the hydrogen molecule concentration in the quartz glass body are set within a predetermined range, the homogeneity of the refractive index may be adversely affected.
In addition, there is a problem that it is difficult to keep the hydrogen molecule concentration within a predetermined range at a relatively low temperature that does not deteriorate the laser resistance and within a time that does not impair the productivity.
本発明はこのような問題点に鑑みてなされたもので、従来よりも短時間で製造することができる、水素分子を含有した耐レーザー性の高い合成石英ガラス体、及びその製造方法を提供することを目的とする。 The present invention has been made in view of such problems, and provides a synthetic quartz glass body containing hydrogen molecules and having high laser resistance, which can be produced in a shorter time than before, and a method for producing the same. For the purpose.
本発明は、上記課題を解決するためになされたもので、円盤形状を有する合成石英ガラス体であって、少なくとも、前記合成石英ガラス体の水素分子濃度が、前記円盤形状の中心軸の中点において2×1016〜4×1017分子/cm3であり、前記中心軸と前記円盤形状の表面との交点部のうち少なくとも一方において2×1017〜2×1018分子/cm3であり、前記中心軸に沿って、該中心軸の中点から前記円盤形状の表面に向かって単調増加であることを特徴とする合成石英ガラス体を提供する。 The present invention has been made in order to solve the above problems, and is a synthetic quartz glass body having a disk shape, and at least the hydrogen molecule concentration of the synthetic quartz glass body is a midpoint of the central axis of the disk shape. 2 × 10 16 to 4 × 10 17 molecules / cm 3 , and 2 × 10 17 to 2 × 10 18 molecules / cm 3 in at least one of the intersections between the central axis and the disk-shaped surface. , along the central axis, it that provide synthetic quartz glass body, wherein the midpoint of the central axis is monotonically increased toward the surface of the disk-shaped.
このような水素分子の濃度分布を有する、円盤形状の合成石英ガラス体であれば、耐レーザー性の高い合成石英ガラス体でありながら、製造する際の水素分子を導入するために必要な処理時間を従来よりも格段に短くした合成石英ガラス体とすることができる。
また、このような合成石英ガラス体であれば、所望の用途に合わせた形状に加工する際の形状補正により屈折率の均質性に及ぼす影響をキャンセル(相殺)することが容易となる。
In the case of a disc-shaped synthetic quartz glass body having such a concentration distribution of hydrogen molecules, the processing time required for introducing hydrogen molecules during manufacture is high while it is a synthetic quartz glass body having high laser resistance. Can be made a synthetic quartz glass body that is much shorter than the conventional one.
Further, with such a synthetic quartz glass body, it becomes easy to cancel (cancel) the influence on the homogeneity of the refractive index by shape correction when processing into a shape suited to a desired application.
この場合、前記中心軸の中点を原点として該中心軸上にx軸をとり、位置x[cm]における水素分子濃度y[分子/cm3]を測定したときの測定値の分布が、二次式によって回帰分析したときの決定係数が0.9〜1.0であり、二次の項の係数が5×1015〜3×1017であることが好ましい。
このように、中心軸上の水素分子濃度分布について、二次式によって回帰分析したときの決定係数が0.9〜1.0であり、二次の項の係数が5×1015〜3×1017であれば、形状を加工する際の形状補正により屈折率の均質性に及ぼす影響をキャンセルすることがより容易となる。
In this case, the distribution of the measured values when the hydrogen molecule concentration y [molecules / cm 3 ] at the position x [cm] is measured with the x axis on the central axis with the midpoint of the central axis as the origin is represented by two determining coefficient when the regression analysis the following equation is 0.9 to 1.0, it is not preferable coefficient of the quadratic terms are 5 × 10 15 ~3 × 10 17 .
Thus, with respect to the hydrogen molecule concentration distribution on the central axis, the coefficient of determination when regression analysis is performed using a quadratic equation is 0.9 to 1.0, and the coefficient of the quadratic term is 5 × 10 15 to 3 ×. If it is 10 17 , it becomes easier to cancel the influence on the homogeneity of the refractive index by shape correction when processing the shape.
また、前記中心軸に沿ったOH基濃度の平均が1〜150wtppmであり、かつ、前記中心軸に沿ったOH基濃度の変動幅が30wtppm以下であることが好ましい。
このように、中心軸に沿ったOH基濃度の平均が1〜150wtppmであり、かつ、中心軸に沿ったOH基濃度の変動幅が30wtppm以下であれば、より高い耐レーザー性を有する合成石英ガラス体とすることができる。
Further, the average OH group concentration along the central axis is 1~150Wtppm, and it is not preferable variation range of the OH group concentration along the central axis is less than 30Wtppm.
Thus, if the average of the OH group concentration along the central axis is 1 to 150 wtppm and the fluctuation range of the OH group concentration along the central axis is 30 wtppm or less, the synthetic quartz having higher laser resistance It can be a glass body.
また、前記中心軸方向の屈折率の均質性が2×10−7〜2×10−6であり、前記中心軸と直交する方向の屈折率の均質性が2×10−7〜2×10−6であることが好ましい。
このように、中心軸方向の屈折率の均質性が2×10−7〜2×10−6であり、中心軸と直交する方向の屈折率の均質性が2×10−7〜2×10−6であれば、形状を加工する際の形状補正により屈折率の均質性に及ぼす影響をキャンセルすることがさらに容易となる。
Further, the homogeneity of the refractive index in the central axis direction is 2 × 10 −7 to 2 × 10 −6 , and the homogeneity of the refractive index in the direction orthogonal to the central axis is 2 × 10 −7 to 2 × 10 6. it is not preferable is -6.
Thus, the homogeneity of the refractive index in the central axis direction is 2 × 10 −7 to 2 × 10 −6 , and the homogeneity of the refractive index in the direction orthogonal to the central axis is 2 × 10 −7 to 2 × 10 6. If it is −6 , it becomes easier to cancel the influence on the homogeneity of the refractive index by the shape correction when processing the shape.
また、前記のような合成石英ガラス体であれば、光学用途に使用することができる。
前記のような合成石英ガラス体は、対レーザー性が高い等の特性を有し、光学用石英ガラス部材の材料として好適である。
Further, if a synthetic quartz glass, such as described above, Ru can be used for optical applications.
The synthetic quartz glass body as described above has characteristics such as high laser resistance and is suitable as a material for optical quartz glass members.
また、本発明は、少なくとも、円盤形状の合成石英ガラス体を作製する工程と、前記合成石英ガラス体に水素分子を含有させる水素分子導入工程とを含み、円盤形状であり、水素分子を含有する合成石英ガラス体を製造する方法において、前記水素分子導入工程を、少なくとも、前記合成石英ガラス体に対し、水素分圧を0.82〜1.5MPa、温度を350〜450℃として、50〜290時間で熱処理を施す段階と、水素分圧を0.01MPa以下、温度を350〜450℃として、150〜2500時間で熱処理を施す段階と、水素分圧を0.05〜0.5MPa、温度を350〜450℃として、100〜1500時間で熱処理を施す段階とを経て行うことを特徴とする合成石英ガラス体の製造方法を提供する。 In addition, the present invention includes at least a step of producing a disc-shaped synthetic quartz glass body and a hydrogen molecule introduction step of containing hydrogen molecules in the synthetic quartz glass body, the disc shape is formed, and contains hydrogen molecules. In the method for producing a synthetic quartz glass body, the hydrogen molecule introduction step is performed at 50 to 290 at a hydrogen partial pressure of 0.82 to 1.5 MPa and a temperature of 350 to 450 ° C. with respect to at least the synthetic quartz glass body. A step of performing heat treatment for a period of time, a step of performing heat treatment for 150 to 2500 hours at a hydrogen partial pressure of 0.01 MPa or less and a temperature of 350 to 450 ° C., a hydrogen partial pressure of 0.05 to 0.5 MPa, and a temperature of as 350 to 450 ° C., that provides a method for manufacturing a synthetic quartz glass body which is characterized in that through the steps of applying a heat treatment at 100 to 1500 hours.
このような合成石英ガラス体の製造方法であれば、水素分子を導入するために必要な処理時間を従来よりも格段に短くして、耐レーザー性の高い合成石英ガラス体を製造することができる。そして、このような合成石英ガラス体の製造方法により製造された合成石英ガラス体であれば、形状を加工する際の形状補正により屈折率の均質性に及ぼす影響をキャンセルすることが容易となる。 With such a method for producing a synthetic quartz glass body, it is possible to produce a synthetic quartz glass body having high laser resistance by significantly shortening the processing time required for introducing hydrogen molecules compared to the conventional method. . And if it is the synthetic quartz glass body manufactured by such a manufacturing method of a synthetic quartz glass body, it will become easy to cancel the influence which acts on the homogeneity of a refractive index by shape correction at the time of processing a shape.
以上のように、本発明に従う合成石英ガラス体であれば、耐レーザー性を確保しつつ、短時間に製造することができ、レンズ形状等への形状加工の際の屈折率補正も容易となる。
また、本発明に従う合成石英ガラス体の製造法であれば、耐レーザー性の高く、レンズ形状等への形状加工の際の屈折率補正が容易な合成石英ガラス体を短時間で製造することができる。
As described above, the synthetic quartz glass body according to the present invention can be manufactured in a short time while ensuring the laser resistance, and the refractive index can be easily corrected when processing the lens shape or the like. .
Also, with the method for producing a synthetic quartz glass body according to the present invention, it is possible to produce a synthetic quartz glass body with high laser resistance and easy refractive index correction during shape processing into a lens shape or the like in a short time. it can.
以下、本発明を詳細に説明するが、本発明はこれらに限定されるものではない。
前述のように、石英ガラス体中の水素分子濃度の最大値と最小値を所定の範囲に収めるようにしたとしても、屈折率の均質性に悪影響を及ぼすことがあるという問題や、耐レーザー性を悪化させないような比較的低温下で、なおかつ生産性を阻害しない時間内で水素分子濃度を所定の範囲内に納めるようにするのは困難であるという問題があった。
Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.
As described above, even if the maximum and minimum values of the hydrogen molecule concentration in the quartz glass body are kept within the predetermined range, there is a problem that the homogeneity of the refractive index may be adversely affected, and the laser resistance. There is a problem that it is difficult to keep the hydrogen molecule concentration within a predetermined range at a relatively low temperature that does not deteriorate the pH and within a time that does not inhibit productivity.
そこで、本発明者は、耐レーザー性を悪化させないような比較的低温下で、生産性を損なわない処理時間で水素分子の導入された合成石英ガラス体を見出すべく、以下のような検討を行った。 Therefore, the present inventor has conducted the following studies in order to find a synthetic quartz glass body into which hydrogen molecules have been introduced at a relatively low temperature that does not deteriorate the laser resistance and in a treatment time that does not impair productivity. It was.
一般に石英ガラスの形状が円盤形状の場合、水素分子の拡散は径方向よりも中心軸方向が支配的となる。したがって、外部からドープされた水素分子の濃度勾配は軸方向の方がきつくなりやすい。さらに径方向につく濃度勾配は円盤形状の石英ガラス体の外周の近傍で現れるため、外周研削等で濃度勾配のついた部分を除去することが可能であるのに対し、軸方向では同様の手段で濃度勾配部を取り除くといった方法が取り難い。なぜならば、このような円盤形状石英ガラスでは、中心の水素濃度を確保するために必要なドープ時間は軸方向の距離、すなわち石英ガラスの厚さに依存するため、水素ドープ過程においては時間をできるだけ短縮しようとする要求から石英ガラスを必要最小限の厚みに加工した状態で行うことが一般に行われており、そこからさらに厚みを減ずる余地は通常残されていないからである。 In general, when the shape of quartz glass is a disk shape, the diffusion of hydrogen molecules is more dominant in the central axis direction than in the radial direction. Therefore, the concentration gradient of hydrogen molecules doped from the outside tends to be tighter in the axial direction. Further, since the concentration gradient in the radial direction appears in the vicinity of the outer periphery of the disc-shaped quartz glass body, it is possible to remove the portion with the concentration gradient by peripheral grinding or the like, whereas in the axial direction, the same means are used. It is difficult to take a method of removing the concentration gradient part. This is because in such a disk-shaped quartz glass, the doping time required to secure the central hydrogen concentration depends on the axial distance, that is, the thickness of the quartz glass, so that the time in the hydrogen doping process can be as long as possible. This is because it is generally performed in a state in which quartz glass is processed to the minimum necessary thickness because of the demand for shortening, and there is usually no room for further reducing the thickness.
つまり、円盤形状の石英ガラス体において、耐レーザー性を向上させるには、中心軸方向の水素分子濃度分布に注目し、これを平坦にすることができればよい。しかしながら、前述のように、耐レーザー性を悪化させないような比較的低温下で、なおかつ生産性を阻害しない時間内でこれを達成するのは困難であるという問題があった。 In other words, in order to improve the laser resistance in a disk-shaped quartz glass body, it is only necessary to pay attention to the hydrogen molecule concentration distribution in the central axis direction and make it flat. However, as described above, there is a problem that it is difficult to achieve this at a relatively low temperature that does not deteriorate the laser resistance and within a time that does not impair the productivity.
図2に、円盤形状の石英ガラス体の形状を模式的に示した。なお、便宜上、円盤形状のうち一部が切除され、断面が示された図を示している。
円盤形状の石英ガラス体11は、中心軸12を中心とした回転対称性を有している。なお、円盤形状とは、平行平板に近い円柱状の形状であり、概ね高さ(中心軸12の長さ)に対して底面の直径が2.5〜8倍程度の寸法である。以下、本明細書中では、中心軸12の中点(すなわち円盤形状の中心)を点O、中心軸12と石英ガラス体11の表面との交点P、中心Oと点Pを両端とする線分OPの中点を点Mとし、線分OP上で点Mよりも点Pに近い位置Nを定義して用いる。なお、特に光学用途に用いるような円盤形状の石英ガラス体は、直径が200〜500mmであることが多いが、これに限定されるものではない。
FIG. 2 schematically shows the shape of a disk-shaped quartz glass body. For the sake of convenience, a diagram in which a part of the disk shape is cut away and a cross section is shown is shown.
The disc-shaped quartz glass body 11 has rotational symmetry about the
本発明者の検討によれば、近年の石英ガラス光学部材への光学特性の要求の厳しさを鑑みると、特許文献1や特許文献2等に見られる水素分子濃度の規定では不十分であり、屈折率の均質性への影響を見据えた、より明確な定義が必要であることがわかった。
すなわち、従来のように、石英ガラス体中の水素分子濃度の最大値と最小値を所定の範囲に収めるようにしたとしても、全体の濃度分布勾配が図12に示すようにいびつなものであったりすると、屈折率の均質性に悪影響を及ぼすことになる。
According to the study of the present inventor, in view of the severe demand for optical properties of quartz glass optical members in recent years, the definition of the hydrogen molecule concentration found in
That is, even if the maximum value and the minimum value of the hydrogen molecule concentration in the quartz glass body are kept within a predetermined range as in the prior art, the overall concentration distribution gradient is irregular as shown in FIG. Would adversely affect the homogeneity of the refractive index.
これらの知見に基づいて本発明者はさらに検討を行い、その結果、円盤形状石英ガラス体の軸方向の水素分子濃度分布が完全に平坦でなくとも、図1に示したように、中心軸方向に沿って水素分子濃度が単調増加的に変化していれば、光学用合成石英ガラス部材として十分な屈折率の均質性が得られることを見出した。すなわち、水素分子濃度分布を完全に平坦にするよりもはるかに短い時間で水素分子の導入を完了することができ、なおかつ水素分子濃度分布が単調増加的に変化していることで、光学用合成石英ガラス体をレンズ状等に加工する際の形状を補正することができ、屈折率の均質性に及ぼす影響をキャンセルすることが可能になることに想到し、本発明を完成させた。 Based on these findings, the present inventor has further studied, and as a result, even if the hydrogen molecule concentration distribution in the axial direction of the disc-shaped quartz glass body is not completely flat, as shown in FIG. It has been found that if the hydrogen molecule concentration is monotonically increasing along the line, the refractive index homogeneity sufficient for an optical synthetic quartz glass member can be obtained. In other words, the introduction of hydrogen molecules can be completed in a much shorter time than completely flattening the hydrogen molecule concentration distribution, and the hydrogen molecule concentration distribution is changing monotonically, so that optical synthesis is possible. The present invention has been completed by conceiving that it is possible to correct the shape when the quartz glass body is processed into a lens shape or the like, and to cancel the influence on the homogeneity of the refractive index.
以下、本発明について図面を参照しながらさらに詳細に説明するが、本発明はこれらに限定されるものではない。 Hereinafter, the present invention will be described in more detail with reference to the drawings, but the present invention is not limited thereto.
まず、本発明に係る合成石英ガラス体を、図2を用いて説明する。本発明に係る合成石英ガラス体は、円盤形状を有する合成石英ガラス体11であり、その水素分子濃度について、円盤形状の中心軸12の中点Oにおいて2×1016〜4×1017分子/cm3であり、中心軸12と円盤形状の合成石英ガラス体11の表面との交点部のうち少なくとも一方において2×1017〜2×1018分子/cm3である。さらに、中心軸12に沿って、水素分子濃度の分布が、中心軸12の中点Oから円盤形状の合成石英ガラス体11の表面に向かって単調増加であることを条件とする。
First, the synthetic quartz glass body according to the present invention will be described with reference to FIG. The synthetic quartz glass body according to the present invention is a synthetic quartz glass body 11 having a disk shape, and the hydrogen molecule concentration is 2 × 10 16 to 4 × 10 17 molecules / in the middle point O of the
なお、本発明では、中心軸と円盤形状の表面との交点部(外表面近傍部分)の水素分子濃度は、外表面から1.5mm内側の位置の値を指す。なぜならば、外表面から1.5mm未満の距離にある領域では水素分子濃度の変化が急峻であり、安定かつ正確な測定結果を得ることができないためである。 In the present invention, the hydrogen molecule concentration at the intersection (the vicinity of the outer surface) between the central axis and the disk-shaped surface indicates a value at a position 1.5 mm inside from the outer surface. This is because the change in the hydrogen molecule concentration is steep in a region at a distance of less than 1.5 mm from the outer surface, and a stable and accurate measurement result cannot be obtained.
このような水素濃度分布を有する合成石英ガラス体であれば、水素分子を含有することで高い耐レーザー性を有しながらも、製造する際の水素分子を導入するために必要な処理時間を従来よりも格段に短くした合成石英ガラス体とすることができる。また、含有する水素分子の濃度分布が単純であるので、円盤形状の合成石英ガラス体を、レンズ状等の所望の形状に加工する際の形状補正により屈折率の均質性に及ぼす影響をキャンセルすることが容易となる。 With a synthetic quartz glass body having such a hydrogen concentration distribution, the processing time required for introducing hydrogen molecules during production is high while having high laser resistance by containing hydrogen molecules. The synthetic quartz glass body can be made much shorter than that. In addition, since the concentration distribution of the hydrogen molecules contained is simple, the influence on the homogeneity of the refractive index is canceled by shape correction when processing a disc-shaped synthetic quartz glass body into a desired shape such as a lens shape. It becomes easy.
合成石英ガラス体11の中心の水素分子濃度は、通常、合成石英ガラス体11で最も小さくなるが、この位置における水素分子濃度が2×1016分子/cm3よりも小さいと十分な耐レーザー性を得ることができない。一方、4×1017分子/cm3を超えるようだと、水素分子の導入に過度に時間を要してしまう。2×1016〜4×1017分子/cm3であることが、耐レーザー性を確保しつつ水素分子導入に必要な時間を過度に長くしない最適な範囲である。 The concentration of hydrogen molecules at the center of the synthetic quartz glass body 11 is usually the smallest in the synthetic quartz glass body 11, but sufficient laser resistance is obtained when the hydrogen molecule concentration at this position is less than 2 × 10 16 molecules / cm 3 . Can't get. On the other hand, when it seems to exceed 4 × 10 17 molecules / cm 3 , it takes excessive time to introduce hydrogen molecules. 2 × 10 16 to 4 × 10 17 molecules / cm 3 is an optimal range in which the time required for introducing hydrogen molecules is not excessively lengthened while ensuring laser resistance.
また、中心軸12に沿って、中心Oから合成石英ガラス体11の外表面との交点Pにかけて水素分子濃度が単調増加していて、かつ中心軸12と上下の少なくとも一方の外表面との交点部(点P近傍)における水素分子濃度が2×1017分子/cm3よりも小さい場合は水素分子濃度分布が非常に平坦であることを意味するが、このような分布にするためには、表面から水素分子を内部に十分に拡散させる必要があり、水素ドープ時間が長くかかり、生産上好ましくないものとなる。
一方、中心軸12と合成石英ガラス体11の外表面との交点部(点Pの近傍)における水素分子濃度が2×1018分子/cm3よりも大きいと、合成石英ガラス体の中心軸12に沿っての水素分子濃度勾配が大きくなりすぎる。この場合、形状補正により屈折率の均質性に及ぼす影響をキャンセルすることが難しくなってしまう。
Further, the hydrogen molecule concentration monotonously increases from the center O to the intersection P with the outer surface of the synthetic quartz glass body 11 along the
On the other hand, when the hydrogen molecule concentration at the intersection (near the point P) between the
なお、本発明において、水素分子濃度が単調に増加するとは、水素分子濃度が中心軸の中点から表面に向けて連続的に増加しており、途中で減少していないことを意味する。このような単調増加分布であれば、例え水素分子濃度に分布があったとしても容易に加工で補正して、所望特性を有する光学部材を得ることが可能となる。 In the present invention, the monotonous increase in the hydrogen molecule concentration means that the hydrogen molecule concentration continuously increases from the center point of the central axis toward the surface and does not decrease in the middle. With such a monotonically increasing distribution, even if there is a distribution in the hydrogen molecule concentration, it is possible to easily correct it by processing to obtain an optical member having desired characteristics.
そして、本発明の合成石英ガラス体では、中心Oを原点として中心軸12上にx軸をとり、位置x[cm]における水素分子濃度y[分子/cm3]を測定し、各測定値の分布を二次式によって回帰分析したときの決定係数が0.9〜1.0であり、二次の項の係数が5×1015〜3×1017であることが好ましい。
この決定係数が0.9を下回る場合には、中心軸に沿った水素分子濃度の分布がいびつなものとなり、合成石英ガラス体を、レンズ状等の形状に加工する際の形状補正から屈折率の均質性に及ぼす影響をキャンセルすることが難しくなるため、決定係数は0.9〜1.0の範囲にあるのがよい。
また、この二次の項の係数は、小さくなると勾配が緩やかであり、大きくなると勾配が急であることを表すが、光学用合成石英ガラス体の厚さは通常40mm〜160mm程度であるため、その範囲としては5×1015〜2×1017となることが適当である。
In the synthetic quartz glass body of the present invention, the x axis is taken on the
When this coefficient of determination is less than 0.9, the distribution of hydrogen molecule concentration along the central axis becomes distorted, and the refractive index is calculated from shape correction when processing a synthetic quartz glass body into a lens shape or the like. Since it becomes difficult to cancel the influence on the homogeneity, the coefficient of determination should be in the range of 0.9 to 1.0.
Further, the coefficient of the quadratic term indicates that the gradient is gentle when it is small, and the gradient is steep when it is large, but the thickness of the optical synthetic quartz glass body is usually about 40 mm to 160 mm. The range is suitably 5 × 10 15 to 2 × 10 17 .
なお、上記回帰分析による決定係数および二次の項の算出方法は以下の通りである。
合成石英ガラス体の中心(すなわち、円盤形状の中心軸の中点)を原点として、中心軸上にx軸をとり、一方の外表面近傍部分から他方の外表面近傍部分まで中心軸に沿って、好ましくは等間隔で少なくとも20点以上、位置x[cm]における水素分子濃度y[分子/cm3]を測定する。
次に、各測定値(xi,yi)(ここでi=1、2、3、…、nとする)に対して、以下の式(1)で表される二次式を当てはめる。
The calculation method of the coefficient of determination and the quadratic term by the above regression analysis is as follows.
Taking the center of the synthetic quartz glass body (that is, the midpoint of the central axis of the disk shape) as the origin, taking the x-axis on the central axis, along the central axis from the vicinity of one outer surface to the vicinity of the other outer surface The hydrogen molecule concentration y [molecules / cm 3 ] at the position x [cm] is measured at preferably at least 20 points at equal intervals.
Next, a secondary expression represented by the following expression (1) is applied to each measurement value (x i , y i ) (where i = 1, 2, 3,..., N).
この式(1)で表される二次式を求めるには、最小二乗法の原理によって、以下に示す式(2)を最小にするa、b、cの値を求めればよい。
そして、この式(2)を最小にするa、b、cの値を求めるには、次の式(3)、(4)、(5)の連立方程式を解けばよい。ただし、cの値(切片)を、円盤形状合成石英ガラス体中心における水素分子濃度[分子/cm3]に等しいと置いて計算してもよい。 And in order to obtain | require the value of a, b, c which minimizes this Formula (2), what is necessary is just to solve the simultaneous equations of following Formula (3), (4), (5). However, the value (intercept) of c may be calculated by setting it equal to the hydrogen molecule concentration [molecules / cm 3 ] at the center of the disk-shaped synthetic quartz glass body.
このようにして求めたa、b、cを用いると、xに対するyの二次の回帰曲線(式2)が得られる。このときのaの値が二次の項の係数である。また、決定係数は一般にR2で表されるが、この場合は以下の式(6)によって表される。 When a, b, and c obtained in this way are used, a quadratic regression curve of y with respect to x (formula 2) is obtained. The value of a at this time is the coefficient of the secondary term. The determination coefficient is generally represented by R 2. In this case, it is represented by the following formula (6).
また、本発明の合成石英ガラス体では、中心軸12に沿ったOH基濃度の平均が1〜150wtppmであり、かつ、中心軸12に沿ったOH基濃度の変動幅が30wtppm以下であることが好ましい。OH基濃度は耐レーザー性に関連があるため、光学用部材として使用するためには、水素濃度分布に加え、上記のようにOH基濃度を規定することが好ましい。加えてOH基濃度の変動は屈折率の均質性に影響を与えるため、該変動幅としては30wtppm以下であることが好ましい。
In the synthetic quartz glass body of the present invention, the average OH group concentration along the
また、屈折率の均質性については、近年の光学用石英ガラス部材への光学的均質性への要求に応えるためには、中心軸12方向および中心軸12と直交する方向のいずれにおいても2×10−7〜2×10−6であることが光学用石英ガラス部材として望ましい。
Further, with respect to the homogeneity of the refractive index, in order to meet the recent demand for optical homogeneity of optical quartz glass members, 2 × both in the direction of the
また、本発明中での各パラメータの測定法は以下の通りである。
(水素分子濃度)
V. K. KHOTIMCHENKO, et al., Determining the content of hydrogen dissolved in quartz glass using the methods of Raman scattering and mass spectrometry, Journal of Applied Spectroscopy, Vol. 46, No. 6, pp. 632−635文献記載のラマン分光光度計による測定法。同一測定点における測定値の繰り返し精度は±2×10−15分子/cm3である。
The measuring method of each parameter in the present invention is as follows.
(Hydrogen molecule concentration)
V. K. KHOTIMCHENKO, et al. , Determinating the content of hydrodissolved in quadz glassing the methods of Raman scattering and mass spectrometry, Journal of Applied Electronics. 46, no. 6, pp. A measurement method using a Raman spectrophotometer described in 632-635. The repeatability of the measured value at the same measurement point is ± 2 × 10 −15 molecules / cm 3 .
(OH基濃度)
D. M. DODD and D. B. FRASER, Optical determination of OH in fused silica, Journal of Applied Physics, Vol. 37(1966)p. 3911文献記載の赤外分光光度計による測定法。石英ガラス体の中心を原点として中心軸上にx軸をとり、一方の外表面近傍部分から他方の外表面近傍部分まで中心軸に沿って、好ましくは、等間隔で少なくとも20点以上測定し、平均OH基濃度を算出する。また、OH基濃度の変動幅とは測定した値の最大値と最小値の差のことをいう。
(OH group concentration)
D. M.M. DODD and D.D. B. FRASER, Optical determination of OH in fused silica, Journal of Applied Physics, Vol. 37 (1966) p. Measurement method using infrared spectrophotometer described in 3911 document. Taking the x-axis on the central axis with the center of the quartz glass body as the origin, and measuring along the central axis from the vicinity of one outer surface to the vicinity of the other outer surface, preferably at least 20 points at equal intervals, The average OH group concentration is calculated. Further, the fluctuation range of the OH group concentration means the difference between the maximum value and the minimum value of the measured values.
(屈折率の均質性)
JIS R3252「ガラスのレーザ干渉法による均質度の測定方法」の記載に基づくHe−Neレーザー(波長632.8nm)を光源とする光干渉計(Zygo社製、Mark GPI xp)による測定。石英ガラス体の中心軸方向については円盤の同心円で直径比90%以上の領域について測定する。また、中心軸に直交する方向については、水素ドープを行った後、図14に記載のように、円盤形状の合成石英ガラス体の外周付近において、互いに平行でかつ中心軸とも平行なオリエンテーションフラット加工を両側に施したのちに測定を行った。オリエンテーションフラットの加工厚さは10mm以下で両側が共に等しい厚さとする。測定の領域はオリエンテーションフラット部の全域とする。
(Homogeneity of refractive index)
Measurement with an optical interferometer (Mark GPI xp, manufactured by Zygo) using a He—Ne laser (wavelength 632.8 nm) as a light source based on the description of JIS R3252 “Method of measuring homogeneity by glass laser interferometry”. With respect to the central axis direction of the quartz glass body, measurement is performed on a concentric circle of the disk and a region having a diameter ratio of 90% or more. Further, in the direction perpendicular to the central axis, after performing hydrogen doping, orientation flat processing parallel to each other and parallel to the central axis is performed in the vicinity of the outer periphery of the disc-shaped synthetic quartz glass body as shown in FIG. The measurement was performed after applying to both sides. The processing thickness of the orientation flat is 10 mm or less, and both sides are equal in thickness. The measurement area is the entire orientation flat.
次に、上記のような合成石英ガラス体を製造する方法について説明する。
本発明に係る合成石英ガラス体の製造方法の一例を図5に示した。
Next, a method for producing the above synthetic quartz glass body will be described.
An example of a method for producing a synthetic quartz glass body according to the present invention is shown in FIG.
まず、図5(a)に示したように、円盤形状の合成石英ガラス体を作製する(工程a)。例えば、まず合成石英ガラスを合成し、これを円盤形状に成形する。
近年では光学用合成石英ガラスの合成方法としては、シリカ原料を火炎加水分解して得られるシリカ微粒子をターゲット上に堆積成長させたのち、透明ガラス化するスート法が主流となっているが、本発明はこれに限定されるものではない。
そして、この合成された合成石英ガラス体を、図2に示したような円盤形状に成形加工を行う。ここでの円盤形状は、例えば、直径が200〜500mmであり、高さに対して直径が2.5〜8倍程度であるような形状とする。
First, as shown in FIG. 5A, a disc-shaped synthetic quartz glass body is produced (step a). For example, first, synthetic quartz glass is synthesized and formed into a disk shape.
In recent years, the synthetic method of synthetic quartz glass for optics is mainly the soot method in which silica fine particles obtained by flame hydrolysis of silica raw material are deposited and grown on a target and then converted into transparent glass. The invention is not limited to this.
Then, the synthesized synthetic quartz glass body is formed into a disk shape as shown in FIG. The disk shape here is, for example, a shape having a diameter of 200 to 500 mm and a diameter of about 2.5 to 8 times the height.
次に、図5(b)に示したように、このようにして製造された円盤形状の合成石英ガラス体に水素分子を含有させる(工程b)。このとき、本発明の合成石英ガラス体の製造方法では、この水素分子導入工程を、少なくとも以下のような3段階の段階を経る。すなわち、第1段階として水素分圧を0.82〜1.5MPa、温度を350〜450℃として、50〜290時間で熱処理を施し(段階b−1)、次に第2段階として水素分圧を0.01MPa以下、温度を350〜450℃として、150〜2500時間で熱処理を施し(段階b−2)、続いて第3段階として水素分圧を0.05〜0.5MPa、350〜450℃、100〜1500時間で熱処理を施す(段階b−3)。各段階での水素分圧、温度、時間は、円盤体の形状、寸法等によって上記範囲内で最適な組み合わせが適宜選択される。 Next, as shown in FIG. 5B, hydrogen molecules are contained in the disc-shaped synthetic quartz glass body thus manufactured (step b). At this time, in the method for producing a synthetic quartz glass body of the present invention, the hydrogen molecule introduction step is performed through at least the following three stages. That is, as the first stage, the hydrogen partial pressure is 0.82 to 1.5 MPa, the temperature is 350 to 450 ° C., and heat treatment is performed for 50 to 290 hours (stage b-1), and then the second stage is hydrogen partial pressure. Is set to 0.01 MPa or less, the temperature is set to 350 to 450 ° C., and heat treatment is performed for 150 to 2500 hours (step b-2). Subsequently, the hydrogen partial pressure is set to 0.05 to 0.5 MPa, 350 to 450 as the third step. A heat treatment is performed at 100 ° C. for 100-1500 hours (step b-3). The hydrogen partial pressure, temperature, and time at each stage are appropriately selected within the above range depending on the shape and dimensions of the disk.
ここで、上記各段階が果たす役割について説明する。
第1段階(段階b−1)の熱処理においては水素分子を石英ガラス中に多く含有させることを目的としている。この段階の熱処理後では図3に示すように水素分子は円盤形状の合成石英ガラス体の外表面付近に多く存在した状態になっている。
Here, the role played by each of the above steps will be described.
The heat treatment in the first stage (stage b-1) is intended to contain a large amount of hydrogen molecules in the quartz glass. After the heat treatment at this stage, as shown in FIG. 3, many hydrogen molecules exist in the vicinity of the outer surface of the disc-shaped synthetic quartz glass body.
第2段階(段階b−2)の実質的に水素を含まない雰囲気での熱処理では水素分子を石英ガラス内部に拡散させるとともに、外表面付近の水素分子濃度が過度に高くなることを抑える効果がある。ここで実質的に水素を含まない雰囲気とは、大部分が大気や窒素、ヘリウムなどの非水素ガスからなり、水素分圧が0.01MPa以下であるような雰囲気を指す。この第2段階終了時の合成石英ガラス体の中心軸に沿った水素分子濃度の分布を表すと図4のようになっている。円盤形状の合成石英ガラス体11の中心軸12と外表面との交点Pにおける水素分子濃度はほとんど0であるが、内部に向かうにつれて濃度が高まり、点Nにおいて最大値をとり、そこから中心Oに向けて徐々に下がっていく。中心Oにおける水素分子濃度は、第1段階後より上がる。
The heat treatment in an atmosphere substantially free of hydrogen in the second stage (stage b-2) has the effect of diffusing hydrogen molecules inside the quartz glass and suppressing the concentration of hydrogen molecules near the outer surface from becoming excessively high. is there. Here, the atmosphere that does not substantially contain hydrogen refers to an atmosphere that is mostly made of non-hydrogen gas such as air, nitrogen, or helium, and has a hydrogen partial pressure of 0.01 MPa or less. FIG. 4 shows a distribution of hydrogen molecule concentration along the central axis of the synthetic quartz glass body at the end of the second stage. The concentration of hydrogen molecules at the intersection P between the
続く第3段階(段階b−3)の低水素分圧中での熱処理によって、交点Pにおける水素分子濃度を2×1017〜2×1018分子/cm3の範囲に上げるとともに、中心の水素分子濃度を2×1016〜4×1017分子/cm3の範囲に収め、中心軸に沿った水素分子濃度は、最終的には図1で示されるような、中心Oから交点Pに向けて単調増加する分布となる。
このような段階を経る熱処理により、例えば、中心を原点として中心軸上にx軸をとり、位置x[cm]における水素分子濃度y[分子/cm3]を測定し、各測定値を二次式によって回帰分析したときの決定係数が0.9〜1.0、二次の項の係数が5×1015〜3×1017であるような合成石英ガラス体を得ることができる。
The subsequent third stage (stage b-3) heat treatment in a low hydrogen partial pressure increases the concentration of hydrogen molecules at the intersection P to a range of 2 × 10 17 to 2 × 10 18 molecules / cm 3 , The molecular concentration is in the range of 2 × 10 16 to 4 × 10 17 molecules / cm 3 , and the hydrogen molecule concentration along the central axis is finally from the center O toward the intersection P as shown in FIG. The distribution increases monotonically.
By the heat treatment through such a stage, for example, the x axis is taken on the center axis with the center as the origin, the hydrogen molecule concentration y [molecule / cm 3 ] at the position x [cm] is measured, and each measured value is secondarily measured. A synthetic quartz glass body having a coefficient of determination of 0.9 to 1.0 and a coefficient of a quadratic term of 5 × 10 15 to 3 × 10 17 when regression analysis is performed using an equation can be obtained.
このような合成石英ガラス体の製造方法であれば、水素分子を合成石英ガラス体に導入する工程における熱処理温度を450℃以下のような低温とするので、石英ガラス中の還元性欠陥の発生を抑制することができ、この還元性欠陥による耐レーザー性の悪化を抑制することができる。 In such a method for producing a synthetic quartz glass body, the heat treatment temperature in the step of introducing hydrogen molecules into the synthetic quartz glass body is set to a low temperature such as 450 ° C. or less. It is possible to suppress the deterioration of the laser resistance due to this reducing defect.
以下に本発明の実施例及び比較例並びに実験例を示して具体的に説明するが、これらの実施例は例示的に示されるものであり、本発明は下記の実施例によって制限されるべきものではない。 Hereinafter, the present invention will be described in detail with reference to examples, comparative examples, and experimental examples. However, these examples are illustrative only, and the present invention should be limited by the following examples. is not.
(実施例1)
図5に示したような、本発明の合成石英ガラス体の製造方法に従って、合成石英ガラス体を製造した。
回転するターゲット上に気化した四塩化珪素を酸水素中で火炎加水分解してシリカスートを堆積させることにより作製した多孔質スート体を真空雰囲気下1000℃で仮焼結したのち真空雰囲気下1600℃で透明ガラス化して円柱形状の石英ガラスインゴットを製造した。上記石英ガラスインゴットを旋盤に固定して酸水素火炎で加熱し、長さ550mm、外径200mmの円柱形状石英ガラス体を得た。上記円柱形状石英ガラス体を内径420mm、高さ280mmの高純度グラファイト製容器に静置し、真空加熱炉にて真空雰囲気下、1800℃にて加熱し自重による変形を行わせる工程を行って、外径420mm、厚さ120mmの円盤形状の石英ガラス成型体を得、さらに表面付近の不純物汚染部分を除去して外径360mm、厚さ80mmの円盤形状の合成石英ガラス体とした。次に該円盤形状合成石英ガラス体を徐歪処理のため、大気加熱炉にて1150℃で45時間保持後、冷却速度2℃/hにて900℃まで徐冷し、その後室温まで放冷を行った。
Example 1
According to the method for producing a synthetic quartz glass body of the present invention as shown in FIG. 5, a synthetic quartz glass body was produced.
A porous soot body prepared by depositing silica soot by flame hydrolysis of silicon tetrachloride vaporized on a rotating target in oxyhydrogen was temporarily sintered at 1000 ° C. in a vacuum atmosphere, and then at 1600 ° C. in a vacuum atmosphere. A transparent vitrified quartz glass ingot was produced. The quartz glass ingot was fixed to a lathe and heated with an oxyhydrogen flame to obtain a cylindrical quartz glass body having a length of 550 mm and an outer diameter of 200 mm. The columnar quartz glass body is placed in a high-purity graphite container having an inner diameter of 420 mm and a height of 280 mm, and heated at 1800 ° C. in a vacuum atmosphere in a vacuum heating furnace to be deformed by its own weight, A disc-shaped quartz glass molded body having an outer diameter of 420 mm and a thickness of 120 mm was obtained, and an impurity-contaminated portion near the surface was removed to obtain a disc-shaped synthetic quartz glass body having an outer diameter of 360 mm and a thickness of 80 mm. Next, the disk-shaped synthetic quartz glass body is subjected to a slow strain treatment, held at 1150 ° C. for 45 hours in an atmospheric heating furnace, then gradually cooled to 900 ° C. at a cooling rate of 2 ° C./h, and then allowed to cool to room temperature. went.
この円盤形状合成石英ガラス体に対し、後掲の表1に示す水素分圧、温度、時間にて水素ドープを行った。水素ドープ後の中心軸方向の屈折率の均質性は1.7×10−6、中心軸方向に直交する方向の屈折率の均質性は1.8×10−6であり、光学部材としての適性は良好であった。その後、該石英ガラス体を分解し、中心軸に沿って一方の外表面近傍部分から他方の外表面近傍部分まで等間隔で水素分子濃度を21点測定したところ、図6に示すような分布となった。この分布に対して二次式による回帰分析を行い、決定係数と二次の項の係数を求めたところ、表1記載の通りとなった。また、水素分子濃度測定と同一測定箇所においてOH基濃度を測定し、平均OH基濃度およびOH基濃度の変動幅を求めたところ、表1記載の通りであった。 This disk-shaped synthetic quartz glass body was doped with hydrogen at the hydrogen partial pressure, temperature, and time shown in Table 1 below. The refractive index homogeneity in the central axis direction after hydrogen doping is 1.7 × 10 −6 , and the refractive index homogeneity in the direction orthogonal to the central axis direction is 1.8 × 10 −6 . Suitability was good. Thereafter, the quartz glass body was disassembled and measured at 21 points at equal intervals from one outer surface vicinity portion to the other outer surface vicinity portion along the central axis. became. A regression analysis was performed on this distribution using a quadratic equation, and the coefficient of determination and the coefficient of the quadratic term were determined. Further, the OH group concentration was measured at the same measurement location as the hydrogen molecule concentration measurement, and the average OH group concentration and the fluctuation range of the OH group concentration were determined.
(実施例2)
回転するターゲット上に気化した四塩化珪素を酸水素中で火炎加水分解してシリカスートを堆積させることにより作製した多孔質スート体を真空雰囲気下1100℃で仮焼結したのち真空雰囲気下1600℃で透明ガラス化して円柱形状の石英ガラスインゴットを製造した。上記石英ガラスインゴットを旋盤に固定して酸水素火炎で加熱し、長さ550mm、外径200mmの円柱形状石英ガラス体を得た。上記円柱形状石英ガラス体を内径420mm、高さ280mmの高純度グラファイト製容器に静置し、真空加熱炉にて真空雰囲気下、1800℃にて加熱し自重による変形を行わせる工程を行って、外径420mm、厚さ120mmの円盤形状の石英ガラス成型体を得、さらに表面付近の不純物汚染部分を除去して外径360mm、厚さ80mmの円盤形状の合成石英ガラス体とした。次に該円盤形状合成石英ガラス体を徐歪処理のため、大気加熱炉にて1150℃で45時間保持後、冷却速度2℃/hにて900℃まで徐冷し、その後室温まで放冷を行った。
(Example 2)
A porous soot body prepared by depositing silica soot by flame hydrolysis of silicon tetrachloride vaporized on a rotating target in oxyhydrogen was temporarily sintered at 1100 ° C. in a vacuum atmosphere, and then at 1600 ° C. in a vacuum atmosphere. A transparent vitrified quartz glass ingot was produced. The quartz glass ingot was fixed to a lathe and heated with an oxyhydrogen flame to obtain a cylindrical quartz glass body having a length of 550 mm and an outer diameter of 200 mm. The columnar quartz glass body is placed in a high-purity graphite container having an inner diameter of 420 mm and a height of 280 mm, and heated at 1800 ° C. in a vacuum atmosphere in a vacuum heating furnace to be deformed by its own weight, A disc-shaped quartz glass molded body having an outer diameter of 420 mm and a thickness of 120 mm was obtained, and an impurity-contaminated portion near the surface was removed to obtain a disc-shaped synthetic quartz glass body having an outer diameter of 360 mm and a thickness of 80 mm. Next, the disk-shaped synthetic quartz glass body is subjected to a slow strain treatment, held at 1150 ° C. for 45 hours in an atmospheric heating furnace, then gradually cooled to 900 ° C. at a cooling rate of 2 ° C./h, and then allowed to cool to room temperature. went.
この円盤形状の合成石英ガラス体に対し、表1に示す水素分圧、温度、時間にて水素ドープを行った。水素ドープ後の中心軸方向の屈折率の均質性は1.6×10−6、中心軸方向に直交する方向の屈折率の均質性は1.8×10−6であり、光学部材としての適性は良好であった。その後、該石英ガラス体を分解し、中心軸に沿って一方の外表面近傍部分から他方の外表面近傍部分まで等間隔で水素分子濃度を21点測定したところ、図7に示すような分布となった。この分布に対して二次式による回帰分析を行い、決定係数と二次の項の係数を求めたところ、表1記載の通りとなった。また、水素分子濃度測定と同一測定箇所においてOH基濃度を測定し、平均OH基濃度およびOH基濃度の変動幅を求めたところ、表1記載の通りであった。 This disk-shaped synthetic quartz glass body was doped with hydrogen at the hydrogen partial pressure, temperature, and time shown in Table 1. The homogeneity of the refractive index in the central axis direction after hydrogen doping is 1.6 × 10 −6 , and the homogeneity of the refractive index in the direction orthogonal to the central axis direction is 1.8 × 10 −6 . Suitability was good. Thereafter, the quartz glass body was disassembled, and the hydrogen molecule concentration was measured at 21 points at equal intervals along the central axis from the vicinity of one outer surface to the vicinity of the other outer surface. The distribution shown in FIG. became. A regression analysis was performed on this distribution using a quadratic equation, and the coefficient of determination and the coefficient of the quadratic term were determined. Further, the OH group concentration was measured at the same measurement location as the hydrogen molecule concentration measurement, and the average OH group concentration and the fluctuation range of the OH group concentration were determined.
(実施例3)
回転するターゲット上に気化した四塩化珪素を酸水素中で火炎加水分解してシリカスートを堆積させることにより作製した多孔質スート体を真空雰囲気下1100℃で仮焼結したのち真空雰囲気下1600℃で透明ガラス化して円柱形状石英ガラスインゴットを製造した。上記石英ガラスインゴットを旋盤に固定して酸水素火炎で加熱し、長さ500mm、外径100mmの円柱形状石英ガラス体を得た。上記円柱形状石英ガラス体を内径260mm、高さ100mmの高純度グラファイト製容器に静置し、真空加熱炉にて真空雰囲気下、1800℃にて加熱し自重による変形を行わせる工程を行って、外径260mm、厚さ70mmの円盤形状の石英ガラス成型体を得、さらに表面付近の不純物汚染部分を除去して外径220mm、厚さ40mmの円盤形状の合成石英ガラス体とした。次に該石英ガラス体を徐歪処理のため、大気加熱炉にて1150℃で45時間保持後、冷却速度2℃/hにて900℃まで徐冷し、その後室温まで放冷を行った。
(Example 3)
A porous soot body prepared by depositing silica soot by flame hydrolysis of silicon tetrachloride vaporized on a rotating target in oxyhydrogen was temporarily sintered at 1100 ° C. in a vacuum atmosphere, and then at 1600 ° C. in a vacuum atmosphere. A cylindrical vitreous silica ingot was produced by vitrification. The quartz glass ingot was fixed to a lathe and heated with an oxyhydrogen flame to obtain a cylindrical quartz glass body having a length of 500 mm and an outer diameter of 100 mm. The columnar quartz glass body is placed in a high purity graphite container having an inner diameter of 260 mm and a height of 100 mm, and heated at 1800 ° C. in a vacuum atmosphere in a vacuum heating furnace to perform deformation by its own weight, A disc-shaped quartz glass molded body having an outer diameter of 260 mm and a thickness of 70 mm was obtained, and an impurity-contaminated portion near the surface was removed to obtain a disc-shaped synthetic quartz glass body having an outer diameter of 220 mm and a thickness of 40 mm. Next, the quartz glass body was kept at 1150 ° C. for 45 hours in an atmospheric heating furnace for slow strain treatment, then slowly cooled to 900 ° C. at a cooling rate of 2 ° C./h, and then allowed to cool to room temperature.
この円盤形状の合成石英ガラス体に対し、表1に示す水素分圧、温度、時間にて水素ドープを行った。水素ドープ後の中心軸方向の屈折率の均質性は1.5×10−6、中心軸方向に直交する方向の屈折率の均質性は1.7×10−6であり、光学部材としての適性は良好であった。その後、該石英ガラス体を分解し、中心軸に沿って一方の外表面近傍部分から他方の外表面近傍部分まで等間隔で水素分子濃度を21点測定したところ、図8に示すような分布となった。この分布に対して二次式による回帰分析を行い、決定係数と二次の項の係数を求めたところ、表1記載の通りとなった。また、水素分子濃度測定と同一測定箇所においてOH基濃度を測定し、平均OH基濃度およびOH基濃度の変動幅を求めたところ、表1記載の通りであった。 This disk-shaped synthetic quartz glass body was doped with hydrogen at the hydrogen partial pressure, temperature, and time shown in Table 1. The homogeneity of the refractive index in the central axis direction after hydrogen doping is 1.5 × 10 −6 , and the homogeneity of the refractive index in the direction perpendicular to the central axis direction is 1.7 × 10 −6 . Suitability was good. Thereafter, the quartz glass body was disassembled, and the hydrogen molecule concentration was measured at 21 points from the vicinity of one outer surface to the vicinity of the other outer surface along the central axis. As a result, the distribution shown in FIG. became. A regression analysis was performed on this distribution using a quadratic equation, and the coefficient of determination and the coefficient of the quadratic term were determined. Further, the OH group concentration was measured at the same measurement location as the hydrogen molecule concentration measurement, and the average OH group concentration and the fluctuation range of the OH group concentration were determined.
(比較例1)
回転するターゲット上に気化した四塩化珪素を酸水素中で火炎加水分解してシリカスートを堆積させることにより作製した多孔質スート体を真空雰囲気下900℃で仮焼結したのち真空雰囲気下1600℃で透明ガラス化して円柱形状石英ガラスインゴットを製造した。上記石英ガラスインゴットを旋盤に固定して酸水素火炎で加熱し、長さ550mm、外径200mmの円柱形状石英ガラス体を得た。上記円柱形状石英ガラス体を内径420mm、高さ280mmの高純度グラファイト製容器に静置し、真空加熱炉にて真空雰囲気下、1800℃にて加熱し自重による変形を行わせる工程を行って、外径420mm、厚さ120mmの円盤形状の石英ガラス成型体を得、さらに表面付近の不純物汚染部分を除去して外径360mm、厚さ80mmの円盤形状の合成石英ガラス体とした。次に該石英ガラス体を徐歪処理のため、大気加熱炉にて1150℃で45時間保持後、冷却速度2℃/hにて900℃まで徐冷し、その後室温まで放冷を行った。
(Comparative Example 1)
A porous soot body prepared by depositing silica soot by flame hydrolysis of silicon tetrachloride vaporized on a rotating target in oxyhydrogen was temporarily sintered at 900 ° C. in a vacuum atmosphere, and then at 1600 ° C. in a vacuum atmosphere. A cylindrical vitreous silica ingot was produced by vitrification. The quartz glass ingot was fixed to a lathe and heated with an oxyhydrogen flame to obtain a cylindrical quartz glass body having a length of 550 mm and an outer diameter of 200 mm. The columnar quartz glass body is placed in a high-purity graphite container having an inner diameter of 420 mm and a height of 280 mm, and heated at 1800 ° C. in a vacuum atmosphere in a vacuum heating furnace to be deformed by its own weight, A disc-shaped quartz glass molded body having an outer diameter of 420 mm and a thickness of 120 mm was obtained, and an impurity-contaminated portion near the surface was removed to obtain a disc-shaped synthetic quartz glass body having an outer diameter of 360 mm and a thickness of 80 mm. Next, the quartz glass body was kept at 1150 ° C. for 45 hours in an atmospheric heating furnace for slow strain treatment, then slowly cooled to 900 ° C. at a cooling rate of 2 ° C./h, and then allowed to cool to room temperature.
この円盤形状の合成石英ガラス体に対し、表1に示す水素分圧、温度、時間にて水素ドープを行った。水素ドープ後の中心軸方向の屈折率の均質性は4.5×10−6、中心軸方向に直交する方向の屈折率の均質性は5.7×10−6と悪化しており、光学部材としての適性は不適であった。その後、該石英ガラス体を分解し、中心軸に沿って一方の外表面近傍部分から他方の外表面近傍部分まで等間隔で水素分子濃度を21点測定したところ、図9に示すような分布となった。この分布に対して二次式による回帰分析を行い、決定係数と二次の項の係数を求めたところ、表1記載の通りとなった。また、水素分子濃度測定と同一測定箇所においてOH基濃度を測定し、平均OH基濃度およびOH基濃度の変動幅を求めたところ、表1記載の通りであった。 This disk-shaped synthetic quartz glass body was doped with hydrogen at the hydrogen partial pressure, temperature, and time shown in Table 1. The homogeneity of the refractive index in the central axis direction after hydrogen doping is 4.5 × 10 −6 , and the homogeneity of the refractive index in the direction perpendicular to the central axis direction is 5.7 × 10 −6. The suitability as a member was unsuitable. Thereafter, the quartz glass body was disassembled and measured at 21 points at equal intervals along the central axis from the vicinity of one outer surface to the vicinity of the other outer surface. As a result, the distribution shown in FIG. became. A regression analysis was performed on this distribution using a quadratic equation, and the coefficient of determination and the coefficient of the quadratic term were determined. Further, the OH group concentration was measured at the same measurement location as the hydrogen molecule concentration measurement, and the average OH group concentration and the fluctuation range of the OH group concentration were determined.
(比較例2)
回転するターゲット上に気化した四塩化珪素を酸水素中で火炎加水分解してシリカスートを堆積させることにより作製した多孔質スート体を真空雰囲気下900℃で仮焼結したのち真空雰囲気下1600℃で透明ガラス化して円柱形状石英ガラスインゴットを製造した。上記石英ガラスインゴットを旋盤に固定して酸水素火炎で加熱し、長さ500mm、外径100mmの円柱形状石英ガラス体を得た。上記円柱形状石英ガラス体を内径260mm、高さ100mmの高純度グラファイト製容器に静置し、真空加熱炉にて真空雰囲気下、1800℃にて加熱し自重による変形を行わせる工程を行って、外径260mm、厚さ70mmの円盤形状の石英ガラス成型体を得、さらに表面付近の不純物汚染部分を除去して外径220mm、厚さ40mmの円盤形状の合成石英ガラス体とした。次に該石英ガラス体を徐歪処理のため、大気加熱炉にて1150℃で45時間保持後、冷却速度2℃/hにて900℃まで徐冷し、その後室温まで放冷を行った。
(Comparative Example 2)
A porous soot body prepared by depositing silica soot by flame hydrolysis of silicon tetrachloride vaporized on a rotating target in oxyhydrogen was temporarily sintered at 900 ° C. in a vacuum atmosphere, and then at 1600 ° C. in a vacuum atmosphere. A cylindrical vitreous silica ingot was produced by vitrification. The quartz glass ingot was fixed to a lathe and heated with an oxyhydrogen flame to obtain a cylindrical quartz glass body having a length of 500 mm and an outer diameter of 100 mm. The columnar quartz glass body is placed in a high purity graphite container having an inner diameter of 260 mm and a height of 100 mm, and heated at 1800 ° C. in a vacuum atmosphere in a vacuum heating furnace to perform deformation by its own weight, A disc-shaped quartz glass molded body having an outer diameter of 260 mm and a thickness of 70 mm was obtained, and an impurity-contaminated portion near the surface was removed to obtain a disc-shaped synthetic quartz glass body having an outer diameter of 220 mm and a thickness of 40 mm. Next, the quartz glass body was kept at 1150 ° C. for 45 hours in an atmospheric heating furnace for slow strain treatment, then slowly cooled to 900 ° C. at a cooling rate of 2 ° C./h, and then allowed to cool to room temperature.
この円盤形状の合成石英ガラス体に対し、表1に示す水素分圧、温度、時間にて水素ドープを行った。水素ドープ後の中心軸方向の屈折率の均質性は3.4×10−6、中心軸方向に直交する方向の屈折率の均質性は4.1×10−6と悪化しており、光学部材としての適性は不適であった。その後、該石英ガラス体を分解し、中心軸に沿って一方の外表面近傍部分から他方の外表面近傍部分まで等間隔で水素分子濃度を21点測定したところ、図10に示すような分布となった。この分布に対して二次式による回帰分析を行い、決定係数と二次の項の係数を求めたところ、表1記載の通りとなった。また、水素分子濃度測定と同一測定箇所においてOH基濃度を測定し、平均OH基濃度およびOH基濃度の変動幅を求めたところ、表1記載の通りであった。 This disk-shaped synthetic quartz glass body was doped with hydrogen at the hydrogen partial pressure, temperature, and time shown in Table 1. The homogeneity of the refractive index in the central axis direction after hydrogen doping is 3.4 × 10 −6 , and the homogeneity of the refractive index in the direction orthogonal to the central axis direction is 4.1 × 10 −6. The suitability as a member was unsuitable. Then, the quartz glass body was disassembled, and the hydrogen molecule concentration was measured at equal intervals from the vicinity of one outer surface to the vicinity of the other outer surface along the central axis, and the distribution shown in FIG. became. A regression analysis was performed on this distribution using a quadratic equation, and the coefficient of determination and the coefficient of the quadratic term were determined. Further, the OH group concentration was measured at the same measurement location as the hydrogen molecule concentration measurement, and the average OH group concentration and the fluctuation range of the OH group concentration were determined.
(比較例3)
回転するターゲット上に気化した四塩化珪素を酸水素中で火炎加水分解してシリカスートを堆積させることにより作製した多孔質スート体を真空雰囲気下1600℃で透明ガラス化して円柱形状石英ガラスインゴットを製造した。上記石英ガラスインゴットを旋盤に固定して酸水素火炎で加熱し、長さ550mm、外径200mmの円柱形状石英ガラス体を得た。上記円柱形状石英ガラス体を内径420mm、高さ280mmの高純度グラファイト製容器に静置し、真空加熱炉にて真空雰囲気下、1800℃にて加熱し自重による変形を行わせる工程を行って、外径420mm、厚さ120mmの円盤形状の石英ガラス成型体を得、さらに表面付近の不純物汚染部分を除去して外径360mm、厚さ80mmの円盤形状の合成石英ガラス体とした。次に該石英ガラス体を徐歪処理のため、大気加熱炉にて1150℃で45時間保持後、冷却速度2℃/hにて900℃まで徐冷し、その後室温まで放冷を行った。
(Comparative Example 3)
A porous soot body prepared by depositing silica soot by flame hydrolysis of silicon tetrachloride vaporized on a rotating target in oxyhydrogen is made into a transparent glass at 1600 ° C. in a vacuum atmosphere to produce a cylindrical quartz glass ingot did. The quartz glass ingot was fixed to a lathe and heated with an oxyhydrogen flame to obtain a cylindrical quartz glass body having a length of 550 mm and an outer diameter of 200 mm. The columnar quartz glass body is placed in a high-purity graphite container having an inner diameter of 420 mm and a height of 280 mm, and heated at 1800 ° C. in a vacuum atmosphere in a vacuum heating furnace to be deformed by its own weight, A disc-shaped quartz glass molded body having an outer diameter of 420 mm and a thickness of 120 mm was obtained, and an impurity-contaminated portion near the surface was removed to obtain a disc-shaped synthetic quartz glass body having an outer diameter of 360 mm and a thickness of 80 mm. Next, the quartz glass body was kept at 1150 ° C. for 45 hours in an atmospheric heating furnace for slow strain treatment, then slowly cooled to 900 ° C. at a cooling rate of 2 ° C./h, and then allowed to cool to room temperature.
この円盤形状の合成石英ガラス体に対し、表1に示す水素分圧、温度、時間にて水素ドープを行った。水素ドープ後の中心軸方向の屈折率の均質性は3.8×10−6、中心軸方向に直交する方向の屈折率の均質性は4.9×10−6と悪化しており、光学部材としての適性は不適であった。その後、該石英ガラス体を分解し、中心軸に沿って一方の外表面近傍部分から他方の外表面近傍部分まで等間隔で水素分子濃度を21点測定したところ、図11に示すような分布となった。この分布に対して二次式による回帰分析を行い、決定係数と二次の項の係数を求めたところ、表1記載の通りとなった。また、水素分子濃度測定と同一測定箇所においてOH基濃度を測定し、平均OH基濃度およびOH基濃度の変動幅を求めたところ、表1記載の通りであった。 This disk-shaped synthetic quartz glass body was doped with hydrogen at the hydrogen partial pressure, temperature, and time shown in Table 1. The homogeneity of the refractive index in the central axis direction after hydrogen doping is 3.8 × 10 −6 , and the homogeneity of the refractive index in the direction orthogonal to the central axis direction is 4.9 × 10 −6. The suitability as a member was unsuitable. Thereafter, the quartz glass body was disassembled and measured at 21 points along the central axis from the vicinity of one outer surface to the vicinity of the other outer surface at equal intervals, and the distribution shown in FIG. became. A regression analysis was performed on this distribution using a quadratic equation, and the coefficient of determination and the coefficient of the quadratic term were determined. Further, the OH group concentration was measured at the same measurement location as the hydrogen molecule concentration measurement, and the average OH group concentration and the fluctuation range of the OH group concentration were determined.
(実験例)
回転するターゲット上に気化した四塩化珪素を酸水素中で火炎加水分解してシリカスートを堆積させることにより作製した多孔質スート体を真空雰囲気下1000℃で仮焼結したのち真空雰囲気下1600℃で透明ガラス化して円柱状の石英ガラスインゴットを製造した。上記石英ガラスインゴットを旋盤に固定して酸水素火炎で加熱し、長さ550mm、外径200mmの円柱状石英ガラス体を得た。上記円柱状石英ガラス体を内径420mm、高さ280mmの高純度グラファイト製容器に静置し、真空加熱炉にて真空雰囲気下、1800℃にて加熱し自重による変形を行わせる工程を行って、外径420mm、厚さ120mmの石英ガラス成型体を得、さらに表面付近の不純物汚染部分を除去して外径360mm、厚さ80mmの石英ガラス体とした。次に該円盤形状合成石英ガラス体を徐歪処理のため、大気加熱炉にて1150℃で45時間保持後、冷却速度2℃/hにて900℃まで徐冷し、その後室温まで放冷を行った。
(Experimental example)
A porous soot body prepared by depositing silica soot by flame hydrolysis of silicon tetrachloride vaporized on a rotating target in oxyhydrogen was temporarily sintered at 1000 ° C. in a vacuum atmosphere, and then at 1600 ° C. in a vacuum atmosphere. A transparent vitrified quartz glass ingot was produced. The quartz glass ingot was fixed to a lathe and heated with an oxyhydrogen flame to obtain a cylindrical quartz glass body having a length of 550 mm and an outer diameter of 200 mm. The columnar quartz glass body is placed in a high purity graphite container having an inner diameter of 420 mm and a height of 280 mm, and is subjected to a process of heating at 1800 ° C. in a vacuum atmosphere in a vacuum heating furnace to cause deformation by its own weight, A quartz glass molded body having an outer diameter of 420 mm and a thickness of 120 mm was obtained, and further, an impurity-contaminated portion near the surface was removed to obtain a quartz glass body having an outer diameter of 360 mm and a thickness of 80 mm. Next, the disk-shaped synthetic quartz glass body is subjected to a slow strain treatment, held at 1150 ° C. for 45 hours in an atmospheric heating furnace, then gradually cooled to 900 ° C. at a cooling rate of 2 ° C./h, and then allowed to cool to room temperature. went.
この円盤形状の合成石英ガラス体に対し、後掲の表1に示す水素分圧、温度、時間にて水素ドープを行った。水素ドープ後の中心軸方向の屈折率の均質性は1.6×10−6、中心軸方向に直交する方向の屈折率の均質性は1.7×10−6であり、光学部材としての適性は良好であったものの、水素ドープに要した時間が5500時間と極めて長く、工業的に量産を行うには不適であった。その後、該石英ガラス体を分解し、中心軸に沿って一方の該表面近傍部分から他方の該表面近傍部分まで等間隔で水素分子濃度を21点測定したところ、図13に示すような分布となった。この分布に対して二次式による回帰分析を行い、決定係数と二次の項の係数を求めたところ、表1記載の通りとなった。また、水素分子濃度測定と同一箇所においてOH基濃度を測定し、平均OH基濃度およびOH基濃度の変動幅を求めたところ、表1記載の通りであった。 This disc-shaped synthetic quartz glass body was doped with hydrogen at the hydrogen partial pressure, temperature, and time shown in Table 1 below. The homogeneity of the refractive index in the central axis direction after hydrogen doping is 1.6 × 10 −6 , and the homogeneity of the refractive index in the direction orthogonal to the central axis direction is 1.7 × 10 −6 . Although the suitability was good, the time required for hydrogen dope was as extremely long as 5500 hours, which was unsuitable for industrial mass production. Thereafter, the quartz glass body was disassembled and measured at 21 points at equal intervals from one surface vicinity to the other surface vicinity along the central axis. The distribution shown in FIG. became. A regression analysis was performed on this distribution using a quadratic equation, and the coefficient of determination and the coefficient of the quadratic term were determined. Further, the OH group concentration was measured at the same location as the hydrogen molecule concentration measurement, and the average OH group concentration and the fluctuation range of the OH group concentration were determined.
なお、本発明は、上記実施形態に限定されるものではない。上記実施形態は単なる例示であり、本発明の特許請求の範囲に記載された技術的思想と実質的に同一な構成を有し、同様な作用効果を奏するものは、いかなるものであっても本発明の技術的範囲に包含される。 The present invention is not limited to the above embodiment. The above embodiment is merely an example, and the present invention has the same configuration as that of the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.
11…石英ガラス体、 12…中心軸。 11 ... quartz glass body, 12 ... central axis.
Claims (1)
少なくとも、前記合成石英ガラス体の水素分子濃度が、
前記円盤形状の中心軸の中点において2×1016〜4×1017分子/cm3であり、
前記中心軸と前記円盤形状の表面との交点部のうち少なくとも一方において2×1017〜2×1018分子/cm3であり、
前記中心軸に沿って、該中心軸の中点から前記円盤形状の表面に向かって単調増加であり、
前記中心軸の中点を原点として該中心軸上にx軸をとり、位置x[cm]における水素分子濃度y[分子/cm3]を測定したときの測定値の分布が、二次式によって回帰分析したときの決定係数が0.9〜1.0であり、二次の項の係数が5×1015〜3×1017であり、
前記中心軸に沿ったOH基濃度の平均が1〜150wtppmであり、かつ、前記中心軸に沿ったOH基濃度の変動幅が30wtppm以下であり、
前記中心軸方向の屈折率の均質性が2×10 −7 〜2×10 −6 であり、前記中心軸と直交する方向の屈折率の均質性が2×10 −7 〜2×10 −6 であり、
光学用途に使用される
ことを特徴とする合成石英ガラス体。 A synthetic quartz glass body having a disk shape,
At least the hydrogen molecule concentration of the synthetic quartz glass body is
2 × 10 16 to 4 × 10 17 molecules / cm 3 at the midpoint of the central axis of the disk shape,
2 × 10 17 to 2 × 10 18 molecules / cm 3 in at least one of the intersections between the central axis and the disk-shaped surface;
Along monoaxially from the midpoint of the central axis toward the disk-shaped surface,
The distribution of measured values obtained by measuring the hydrogen molecule concentration y [molecules / cm 3 ] at the position x [cm] with the midpoint of the central axis as the origin and the x axis on the central axis is expressed by a quadratic expression determining coefficient when the regression analysis is 0.9 to 1.0, Ri coefficient 5 × 10 15 ~3 × 10 17 der of the quadratic terms,
The average of the OH group concentration along the central axis is 1 to 150 wtppm, and the fluctuation range of the OH group concentration along the central axis is 30 wtppm or less,
The homogeneity of the refractive index in the central axis direction is 2 × 10 −7 to 2 × 10 −6 , and the homogeneity of the refractive index in the direction orthogonal to the central axis is 2 × 10 −7 to 2 × 10 −6. And
A synthetic quartz glass body characterized by being used for optical applications .
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