JP4470054B2 - Synthetic quartz glass and manufacturing method thereof - Google Patents

Synthetic quartz glass and manufacturing method thereof Download PDF

Info

Publication number
JP4470054B2
JP4470054B2 JP2003208904A JP2003208904A JP4470054B2 JP 4470054 B2 JP4470054 B2 JP 4470054B2 JP 2003208904 A JP2003208904 A JP 2003208904A JP 2003208904 A JP2003208904 A JP 2003208904A JP 4470054 B2 JP4470054 B2 JP 4470054B2
Authority
JP
Japan
Prior art keywords
quartz glass
synthetic quartz
less
content
resistance
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 - Fee Related
Application number
JP2003208904A
Other languages
Japanese (ja)
Other versions
JP2005067913A (en
Inventor
秀春 堀越
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tosoh Corp
Original Assignee
Tosoh Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Tosoh Corp filed Critical Tosoh Corp
Priority to JP2003208904A priority Critical patent/JP4470054B2/en
Publication of JP2005067913A publication Critical patent/JP2005067913A/en
Application granted granted Critical
Publication of JP4470054B2 publication Critical patent/JP4470054B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • 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
    • C03B19/1461—Thermal after-treatment of the shaped article, e.g. dehydrating, consolidating, sintering for doping the shaped article with flourine
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/06—Glass compositions containing silica with more than 90% silica by weight, e.g. quartz
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C4/00—Compositions for glass with special properties
    • C03C4/0085—Compositions for glass with special properties for UV-transmitting glass
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2201/00—Glass compositions
    • C03C2201/06—Doped silica-based glasses
    • C03C2201/08—Doped silica-based glasses containing boron or halide
    • C03C2201/12—Doped silica-based glasses containing boron or halide containing fluorine
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2201/00—Glass compositions
    • C03C2201/06—Doped silica-based glasses
    • C03C2201/20—Doped silica-based glasses containing non-metals other than boron or halide
    • C03C2201/21—Doped silica-based glasses containing non-metals other than boron or halide containing molecular hydrogen
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2201/00—Glass compositions
    • C03C2201/06—Doped silica-based glasses
    • C03C2201/20—Doped silica-based glasses containing non-metals other than boron or halide
    • C03C2201/23—Doped silica-based glasses containing non-metals other than boron or halide containing hydroxyl groups
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2203/00—Production processes
    • C03C2203/40—Gas-phase processes
    • C03C2203/42—Gas-phase processes using silicon halides as starting materials
    • C03C2203/44—Gas-phase processes using silicon halides as starting materials chlorine containing
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C2203/00—Production processes
    • C03C2203/50—After-treatment
    • C03C2203/52—Heat-treatment
    • C03C2203/54—Heat-treatment in a dopant containing atmosphere
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
    • Y02P40/57—Improving the yield, e-g- reduction of reject rates

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Glass Melting And Manufacturing (AREA)
  • Glass Compositions (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は、Ｘ線等の放射線及びＡｒＦエキシマレーザー等の波長２００ｎｍ以下の真空紫外線照射に対して優れた耐放射線・耐紫外線特性を有する合成石英ガラス及びその製造方法に関するものである。
【０００２】
【従来の技術】
合成石英ガラスは、赤外から真空紫外（＜２００ｎｍ）までの広い波長範囲において透明である事から、各種光学部材に用いられている。ＫｒＦエキシマレーザー等の紫外線用の光学素材として用いるため、ＯＨ基濃度を高くする事で耐性を高める試みがなされている（例えば、特許文献１参照）。
【０００３】
【発明が解決しようとする課題】
しかしながら、ＯＨ基は真空紫外域で吸収を示すため、ＯＨ基濃度を高めると真空紫外領域の透過率が低下する問題がある。また、高エネルギー密度のエキシマレーザーの照射あるいはＸ線等のより短波長光の照射により、ＯＨ基が解裂して新たな欠陥を生成し、透過率が低下する問題もある。
【０００４】
ＯＨ基による吸収の問題を解決する方法として、低ＯＨ基濃度の石英ガラスに予め紫外線を照射して積極的に欠陥を生成させ、熱処理により欠陥を取り除く方法が提案されている（例えば、特許文献２参照）。本方法によれば、予め照射した紫外線と同等の紫外線照射に対する耐性の向上は期待できるが、耐性改善のための照射に比べて、より長時間または、より高エネルギー密度での紫外線照射に対して、あるいは、より短波長（高エネルギー）の紫外線照射に対しての耐性は改善されない。また、紫外線照射処理が必要なため、処理が煩雑になると共に、余分なコストが必要となる問題もある。
【０００５】
この他、ＯＨ基濃度を低減させた合成石英ガラスに、フッ素（Ｆ）を含有させると真空紫外域での透過率及び真空紫外線照射耐性が向上するとの報告がなされている（例えば、非特許文献１参照）。Ｆを含有させる事で照射初期の透過率は改善されるが、高エネルギー密度での紫外線照射や、Ｘ線等の放射線照射に対する耐性は十分でない。
【０００６】
【特許文献１】
特開２０００−７３４９号公報（第３頁）
【特許文献２】
特許第３０５４４１２号公報（第２頁）
【非特許文献１】
梶尾 他、「深紫外−真空紫外域光学材料としてのシリカガラス」、Ｎｅｗ Ｇｌａｓｓ、社団法人ニューガラスフォーラム、２００２年１２月２日、第１７巻、第４号、ｐ．３１〜３５
【０００７】
【課題を解決するための手段】
本発明者は、上記課題を解決するため合成石英ガラスの諸物性と、耐放射線性・耐紫外線性との相関について鋭意検討を行った結果、合成石英ガラスのＯＨ基含有量、Ｆ含有量、Ｓｉ−Ｈ含有量及び酸素欠乏型欠陥及び酸素過剰型欠陥の濃度が、放射線耐性及び真空紫外線照射耐性に対して特に重要であり、それぞれの値を特定の範囲に制限することで、耐放射線・耐紫外線特性に優れた合成石英ガラスを得る事が出来る事を見出した。
【０００８】
すなわち本発明は、ＯＨ基含有量が２〜５０ｐｐｍ、Ｆ含有量が５００〜２０００ｐｐｍ、Ｓｉ−Ｈ結含有量が１×１０17個／ｃｍ3以下、酸素欠乏型欠陥及び酸素過剰型欠陥の濃度が共に１×１０16個／ｃｍ3以下、波長１６３ｎｍにおける内部透過率が１ｃｍあたり６０％以上かつ、ＡｒＦエキシマレーザーをエネルギー密度１０ｍＪ／ｃｍ2で１×１０6ショット照射した時の波長２１５ｎｍの吸収係数変化が０．００１ｃｍ-1以下である事を特徴とする合成石英ガラスであり、その中でも、Ｘ線を照射線量率２×１０4Ｃ／ｋｇ・ｈ（Ｒｈ管球、管電圧５０ｋＶ、管電流５０ｍＡ）で２時間照射した時の波長２１５ｎｍにおける吸収係数変化が０．１ｃｍ-1以下である事を特徴とする合成石英ガラスであり、さらに、そのＨ2含有量が１×１０17個／ｃｍ3以下である事を特徴とする合成石英ガラスである。
【０００９】
また、ガラス形成原料を酸水素火炎中で火炎加水分解して得られたシリカ微粒子をターゲット上に堆積させスート体を合成し、その後の熱処理で透明ガラス化するいわゆるスート法において、酸水素火炎におけるＨ2とＯ2とのモル比（Ｈ2／Ｏ2比）を２．０〜３．０としてスート体を合成し、スート体をＦ元素含有ガスで熱処理した後、透明ガラス化を１３００〜１５５０℃で行う工程を含む事を特徴とする、前記物性の合成石英ガラスの製造方法及び前記物性の合成石英ガラスを、真空紫外線用光学部材として使用する用途も本願発明の範囲に含まれる。
【００１０】
以下、本発明を詳細に説明する。
【００１１】
合成石英ガラス中のＯＨ基は真空紫外域で吸収を示すため、ＯＨ基含有量が少ない程真空紫外域での透過率は上昇する。真空紫外域で十分な透過率を得るためには、ＯＨ基濃度は２〜５０ｐｐｍ、好ましくは、５〜３０ｐｐｍとする。
【００１２】
ＯＨ基濃度が２ｐｐｍ未満になると真空紫外域の透過率が低下するだけでなく、放射線・紫外線耐性が低下してしまう。このようなＯＨ基の作用については明らかではないが、ＯＨ基には、不安定な石英ガラスのアモルファス構造を安定化させる効果があるためと考えられる。
【００１３】
Ｆには、真空紫外領域での透過率を向上させる作用があるため、合成石英ガラスにはＦを含有させる事が好ましい。ただし、Ｆ含有量が高くなると、合成石英ガラスをアニール及び成型等で熱処理した際に、Ｆにより石英ガラスが腐食され新たな構造欠陥が生成し、透過率及び耐性に悪影響を及ぼす事があり、また、Ｓｉ−Ｆ結合も増加する。この結合は石英ガラスの構造に歪みを生じさせ石英ガラスの構造が不安定となり、放射線・紫外線耐性を悪化させてしまうため、石英ガラス中に含有するＦ濃度は５００〜２０００ｐｐｍ、好ましくは、７００〜１６００ｐｐｍとする。
【００１４】
通常、合成石英ガラスは酸水素火炎を用いて合成されるが、火炎中のＨ2の一部は石英ガラス中に取り込まれ、Ｓｉ−Ｈ結合を生成する。Ｓｉ−Ｈ結合は石英ガラスの≡Ｓｉ−Ｏ−Ｓｉ≡結合と比べて結合エネルギーが小さく、放射線・紫外線照射により容易に解裂し欠陥の原因となるため、その含有量を一定量以下に制限する必要があり、具体的にはＳｉ−Ｈ結合の含有量として、１×１０17個／ｃｍ3以下、好ましくは、０．５×１０17個／ｃｍ3以下とすることで放射線・紫外線耐性の高い合成石英ガラスとなる。
【００１５】
合成石英ガラスは、≡Ｓｉ−Ｏ−Ｓｉ≡結合がランダムにつながった構造であるが、製造条件により、酸素原子（Ｏ）が欠乏した欠陥（酸素欠乏型欠陥、≡Ｓｉ−Ｓｉ≡）や、Ｏが過剰の欠陥（酸素過剰型欠陥、≡Ｓｉ−Ｏ−Ｏ−Ｓｉ≡）が生成する。これらの構造は≡Ｓｉ−Ｏ−Ｓｉ≡結合と比べて結合エネルギーが小さく、放射線・紫外線照射により容易に解裂して放射線・紫外線照射耐性を低下させる。さらに、これらの欠陥は隣接する≡Ｓｉ−Ｏ−Ｓｉ≡結合を歪ませ石英ガラスの構造を不安定にし、放射線・紫外線照射耐性に悪影響を及ぼす。
【００１６】
従って、これら欠陥の含有量を一定量以下に制限する必要があり、酸素欠乏型欠陥及び酸素過剰型欠陥の含有量は、共に１×１０16個／ｃｍ3以下、好ましくは０．５×１０16個／ｃｍ3以下にすればよい。
【００１７】
放射線・紫外線照射耐性に悪影響を及ぼす酸素過剰型欠陥は、Ｈ2過剰の条件で合成を行うことで生成が抑制される。この時、Ｈ2が過剰になり過ぎると、酸素欠乏型欠陥を生成し放射線・紫外線耐性が低下するため、合成時のＨ2濃度の制御は重要である。過剰なＨ2の一部は石英ガラス中に取り込まれるが、このＨ2は放射線・紫外線照射により生じた欠陥と反応して、容易にＳｉ−Ｈ結合を生成する。既に述べた様にＳｉ−Ｈ結合は放射線・紫外線耐性に悪影響を及ぼす。また、石英ガラス中に取り込まれたＨ2の還元作用により、新たに酸素欠乏型欠陥が生成し、放射線・紫外線照射耐性が低下する。
【００１８】
従って、石英ガラス中のＨ2含有量を一定量以下に制限することが重要である事が分った。本発明の放射線・紫外線照射耐性の高い合成石英ガラスが得るには、Ｈ2の含有量は１×１０17個／ｃｍ3以下にすることが好ましい。
【００１９】
通常、合成雰囲気中のＨ2濃度が高くなると石英ガラス中のＨ2含有量もそれに伴って増加するため、合成時のＨ2濃度管理は耐放射線・耐紫外線合成石英ガラスの製造にとって重要である。
【００２０】
上述したような条件を併せ持つことにより、本発明の合成石英ガラスは、波長１６３ｎｍにおける内部透過率が１ｃｍあたり６０％以上かつ、ＡｒＦエキシマレーザーをエネルギー密度１０ｍＪ／ｃｍ2で１×１０6ショット照射した時の波長２１５ｎｍの吸収係数変化が０．００１ｃｍ-1以下となり、また、Ｘ線を照射線量率２×１０4Ｃ／ｋｇ・ｈ（Ｒｈ管球、管電圧５０ｋＶ、管電流５０ｍＡ）で２時間照射した時の波長２１５ｎｍにおける吸収係数変化が０．１ｃｍ-1以下となり、耐放射線性・耐紫外線性に優れたものとなる。
【００２１】
金属不純物（アルカリ金属、アルカリ土類金属、遷移金属、その他の金属）は真空紫外域に吸収を示すためその含有量は出来るだけ少ない方が望ましい。金属不純物含有量が多くなると、真空紫外域の透過率が低下するだけでなく、放射線・紫外線照射により金属不純物に起因する欠陥が生成し、所望の耐性が得られない。耐性に影響する金属不純物とその含有量について検討した結果、Ｌｉ，Ｎａ，Ｋなどのアルカリ金属、Ｍｇ，Ｃａなどのアルカリ土類金属、Ｔｉ，Ｃｒ，Ｆｅ，Ｎｉ，Ｃｕ，Ｚｒ，Ｍｏなどの遷移金属、その他Ａｌなどの金属が放射線・紫外線照射耐性を低下させる事が分かり、その含有量と耐性との関係から、本発明の放射線・紫外線照射耐性の高い合成石英ガラスが得るには、金属不純物の総量が５０ｐｐｂ以下が好ましく、さらに２０ｐｐｂ以下、特に１０ｐｐｂ以下が好ましい。
【００２２】
合成石英ガラスでは一般的に、取り扱いやすさ、価格の点などから原料にＳｉＣｌ4が用いられる。このため、合成された石英ガラスには、Ｃｌが残存する可能性があり、このＣｌはガラス内部で直接Ｓｉと結合して≡Ｓｉ−Ｃｌの形態で存在していると考えられる。この≡Ｓｉ−Ｃｌ結合は、放射線・紫外線照射により容易に解裂し欠陥の原因となるため、Ｃｌ含有量は出来るだけ低い方が好ましい。Ｃｌ含有量は１０ｐｐｍ以下であれば耐放射線・耐紫外線合成石英ガラスとして十分満足出来る性能が得られ、より好ましくは１ｐｐｍ以下で、より高い性能が得られる。
【００２３】
次に本発明の合成石英ガラスの製造方法について説明する。本発明の耐放射線・耐紫外線に優れた合成石英ガラスの製造方法は、運転操作性、生産性、品質安定性、コストなどからスート法が好ましい。以下、スート法について具体的に説明する。
【００２４】
スート法では、例えば、多重管構造の石英ガラス製バーナーの中心からＳｉＣｌ4などの原料を供給し、その外側の管からＨ2およびＯ2を供給して原料を火炎加水分解してシリカ微粒子を合成する。この時のＨ2とＯ2との比を理論量２．０よりＨ2過剰とすることで、酸素過剰型欠陥の生成を抑制できる。ただし、比が３．０を越えると、Ｈ2過剰となり、Ｈ2および酸素欠乏型欠陥の濃度を適切な範囲に保てなくなるので、Ｈ2とＯ2との比は、２．０〜３．０、好ましくは、２．２〜２．６の範囲であることが必要である。
【００２５】
このシリカ微粒子は多量のＯＨ基を含有するため、第１の熱処理として、還元性ガス含有雰囲気で処理を行い、ＯＨ基濃度を適切な範囲まで低減させる。第１の熱処理の条件は特に限定されるものではなく、所望のＯＨ基濃度が得られる条件であればよい。第１の熱処理において、Ｆを含有させるため５００〜１１００℃、好ましくは６００〜８００℃の温度範囲で、Ｆ含有ガス雰囲気による処理を含む事が好ましい。処理時間としては、１〜１０時間が好ましい。
【００２６】
第１の熱処理は、Ｆを含有しないガスによる処理とＦ含有ガスによる処理を併用してもよいし、Ｆ含有ガス処理を単独で行なってもよい。Ｆ含有ガスによる処理温度が１１００℃より高いと、≡Ｓｉ−Ｆ結合が過剰となり石英ガラスの構造が不安定になるばかりでなく、Ｆ含有ガスと石英ガラスの≡Ｓｉ−Ｏ−Ｓｉ≡結合との反応が促進されて還元型欠陥が生成する。逆に５００℃より低い温度で処理するとＦとＯＨ基との反応が不十分となり、所望の濃度Ｆが含有されない。
【００２７】
Ｆを含有するガスとしては、ＳｉＦ4等を例示することができ、Ｆを含有しないガスとしては、Ｃｌ2、ＣＯ等を例示することができる。
【００２８】
第１の熱処理に続いて、１３００℃〜１５５０℃の温度範囲で第２の熱処理を行い、透明ガラス化する。第２の熱処理が１３００℃より低いと透明な石英ガラスが得られない。逆に１５５０℃より高い温度で処理すると、透明ガラス化が急速に進行して構造が不安定となるため、所望の性能が得られない。好ましい処理条件としては、１３５０〜１４５０℃で、１〜１０時間加熱すればよい。
【００２９】
また、第２の熱処理を行う際の雰囲気としては、Ｈｅ等の不活性ガス雰囲気や不活性ガスに酸素を含有させた雰囲気等を例示することができ、透明ガラス化の際に酸素欠乏型欠陥の生成を抑制するという点で酸素を含有させたガスが好ましい。
【００３０】
原料は、取り扱いおよび入手が容易で、かつ安価であるなどの点からＳｉＣｌ4が望ましい。しかし、本発明は特にこれに限定されるものではない。原料にＳｉＣｌ4などのＣｌ含有ケイ素化合物を使用した場合、金属不純物は塩化物として系外に除去されるため、特別な処理を行う事なく金属不純物含有量を５０ｐｐｂ以下にする事が出来る。
【００３１】
原料にＳｉＣｌ4の様なＣｌ含有物を用いた場合、スート中にＣｌが残留するが、この残留したＣｌは、第１の熱処理の際、ＯＨ基と共に除去されるため特別な処理を行う事なく、Ｃｌ濃度を１０ｐｐｍ以下にする事ができる。
【００３２】
なお、本発明で規定した以外の製造条件については、従来のスート法の一般的な実施条件を適応することができる。
【００３３】
以上記述した条件で合成石英ガラスを製造すれば、汎用的な製造方法、製造設備により、安価で優れた放射線・紫外線照射耐性を有する、耐放射線・耐紫外線合成石英ガラスを得る事が可能である。
【００３４】
このようにして合成した石英ガラスを、所定の形状に加工、研磨して真空紫外線用光学素材として使用した場合、優れた真空紫外線照射耐性を示し、真空紫外線用光学素材としての使用に特に適している。
【００３５】
【実施例】
以下の実施例により本発明を具体的に説明するが、本発明はこれら実施例に何等限定されるものではない。なお、以下の実施例において、希釈ガスとしてはＨｅを用いた。
【００３６】
実施例１
原料にＳｉＣｌ4を使用して、スート法により合成石英ガラスインゴットを製造した。石英ガラス製バーナーの中心管から原料を供給し、バーナーの外管からＨ2およびＯ2をＨ2／Ｏ2比（モル比）が２．３となるように供給してスート体を合成した。このスート体を第１の熱処理として、１０ｖｏｌ％（容積％）Ｃｌ2ガス（残部はＨｅ）雰囲気下、１１００℃で２時間熱処理後、０．１ｖｏｌ％ＳｉＦ4ガス（残部はＨｅ）雰囲気下、６００℃で２時間熱処理を行った。第１の熱処理を行ったスート体を、Ｈｅガス雰囲気で１５００℃、５時間熱処理して合成石英ガラスインゴットを得た。
【００３７】
続いて、１００％Ｈ2雰囲気、５００℃、５時間処理して、Ｈ2を含浸させたインゴットを得た。以下の実施例・比較例において、得られたインゴットから厚さ１０ｍｍのテストピースを切り出し、評価用試料とした。
【００３８】
実施例２
Ｈ2／Ｏ2比を２．３とし、Ｈ2含浸処理を行わなかった他は、実施例１と同様に行い、合成石英ガラスインゴットを得た。
【００３９】
実施例３
原料にＳｉＣｌ4を使用して、スート法により合成石英ガラスインゴットを製造した。石英ガラス製バーナーの中心管から原料を供給し、バーナーの外管からＨ2およびＯ2をＨ2／Ｏ2比が２．２となるように供給してスート体を合成した。このスート体を第１の熱処理として、１ｖｏｌ％ＳｉＦ4ガス雰囲気下、６００℃で５時間熱処理を行った。その後、第２の熱処理として、Ｈｅガス雰囲気下で１５００℃、５時間熱処理して合成石英ガラスインゴットを得た。得られたインゴットを１００％Ｈ2雰囲気下、５００℃、５時間処理して、Ｈ2を含浸させて合成石英ガラスインゴットを得た。
【００４０】
実施例４
原料にＳｉＣｌ4を使用して、スート法により合成石英ガラスインゴットを製造した。石英ガラス製バーナーの中心管から原料を供給し、バーナーの外管からＨ2およびＯ2をＨ2／Ｏ2比が２．２となるように供給してスート体を合成した。このスート体を第１の熱処理として、１ｖｏｌ％ＳｉＦ4ガス雰囲気下、６００℃で５時間熱処理を行った。その後、第２の熱処理として、Ｈｅガス雰囲気下で１５００℃、５時間熱処理して合成石英ガラスインゴットを得た。
【００４１】
実施例５
原料にＳｉＣｌ4を使用して、スート法により合成石英ガラスインゴットを製造した。石英ガラス製バーナーの中心管から原料を供給し、バーナーの外管からＨ2およびＯ2をＨ2／Ｏ2比が２．２となるように供給してスート体を合成した。このスート体を第１の熱処理として、０．１ｖｏｌ％ＳｉＦ4ガス雰囲気下、８００℃で５時間熱処理を行った。その後、第２の熱処理として、１０％Ｏ2ガス雰囲気下で１５００℃、５時間熱処理して合成石英ガラスインゴットを得た。
【００４２】
実施例６
Ｈ2／Ｏ2比を２．６とし、第１の熱処理を１０００℃とした他は、実施例５と同様に行い、合成石英ガラスインゴットを得た。
【００４３】
実施例７
原料にＳｉＣｌ4を使用して、スート法により合成石英ガラスインゴットを製造した。石英ガラス製バーナーの中心管から原料を供給し、バーナーの外管からＨ2およびＯ2をＨ2／Ｏ2比が２．２となるように供給してスート体を合成した。このスート体を第１の熱処理として、１０ｖｏｌ％ＣＯガス雰囲気下、１１００℃で５時間熱処理後、０．１ｖｏｌ％ＳｉＦ4ガス雰囲気下、６００℃で２時間熱処理を行った。第１の熱処理を行ったスート体を、Ｈｅガス雰囲気下で１５００℃、５時間熱処理して合成石英ガラスインゴットを得た。
【００４４】
実施例１〜７の試料の製造条件をまとめて表１に示し、各試料の評価結果の一覧を表２に示す。
【００４５】
なお、各試料の含有成分の定量方法は以下の通りである。
【００４６】
ＯＨ基含有量は約２．７μｍの吸収からＩＲ測定法により定量した。
【００４７】
Ｓｉ−Ｈ及びＨ2含有量は、ラマン分光測定法で定量した。Ｓｉ−Ｈ及びＨ2に対応するピークはそれぞれ、約２２５０ｃｍ-1に及び約４１５０ｃｍ-1あらわれる。このピークの面積強度と石英ガラスの基本構造による約８００ｃｍ-1のピークの面積強度との比からＳｉ−Ｈ及びＨ2含有量を算出した。
【００４８】
酸素欠乏型欠陥については、ＶＵＶスペクトルを測定し、１６３ｎｍの吸収係数から、酸素過剰型欠陥は、ＶＵＶ及びＵＶスペクトルを測定し、１８５ｎｍ及び３２６ｎｍの吸収係数から濃度を算出して評価した。
【００４９】
Ｆ含有量は、得られた石英ガラスをアルカリ溶融してイオンクロマト法で求めた。金属不純物含有量はＩＣＰ質量分析法で求めた。Ｃｌ含有量は検量線法により蛍光Ｘ線測定法で定量した。
【００５０】
ＡｒＦエキシマレーザーを１パルス当たりのエネルギー密度１０ｍＪ／ｃｍ2で１×１０6パルス照射し、照射前後のＵＶスペクトルから２１５ｎｍの吸収係数を求め、レーザー耐性を評価した。
【００５１】
Ｘ線を照射線量率２×１０4Ｃ／ｋｇ・ｈ（蛍光Ｘ線装置に試料をセットしてＸ線照射試験を行った。照射条件は、Ｒｈ管球、管電圧５０ｋＶ、管電流５０ｍＡ）で２時間照射し、照射前後の２１５ｎｍの吸収係数を求め、放射線耐性を評価した。
【００５２】
比較例１
Ｈ2／Ｏ2比を１．８とした以外は実施例５と同等な条件で合成石英ガラスインゴットを得た。この試料は、酸素過剰型欠陥濃度が２×１０16個／ｃｍ3であった。この試料における初期透過率は６０％であったが、放射線及び紫外線耐性が劣っていた。
【００５３】
比較例２
Ｈ2／Ｏ2比を３．２とした以外は実施例５と同等な条件で合成石英ガラスインゴットを得た。この試料は、酸素欠乏型欠陥濃度が５×１０16個／ｃｍ3であった。この試料における初期透過率は８５％であったが、放射線及び紫外線耐性が劣っていた。
【００５４】
比較例３
第１の熱処理を４００℃で行う以外は、実施例５と同等な条件で合成石英ガラスインゴットを得た。この試料のＯＨ基及びＦ含有量は、それぞれ、８０ｐｐｍ及び５５０ｐｐｍであった。この試料の透過率は４５％と低かった。また、Ｘ線及びエキシマレーザーを照射すると２１５ｎｍに吸収が生じ、耐性も劣っていた。
【００５５】
比較例４
第１の熱処理を１００％Ｎ2雰囲気下で、１３００℃で5時間行った後、０．１ｖｏｌ％ＳｉＦ4雰囲気下、１１００℃で5時間行った事以外は、実施例５と同等な条件で合成石英ガラスインゴットを得た。この試料のＯＨ基及びＦ含有量は、それぞれ、１ｐｐｍ及び１８５０ｐｐｍであり、初期透過率は９５％と高いが、放射線照射耐性に劣っていた。
【００５６】
比較例５
第１の熱処理を１２００℃で行った以外は、実施例５と同等な条件で合成石英ガラスインゴットを得た。この試料のＯＨ基及びＦ含有量は、それぞれ、５ｐｐｍ及び２２５０ｐｐｍ、酸素欠乏型欠陥濃度が７×１０16個／ｃｍ3であった。初期透過率が８０％と高かったが、放射線及び紫外線照射耐性が劣っていた。
【００５７】
比較例６
第２の熱処理を１２５０℃で行った以外は、実施例５と同等な条件で石英ガラスを合成した。この条件では、透明な石英ガラスが得られなかった。
【００５８】
比較例７
第２の熱処理を１６５０℃で行った以外は、実施例５と同等な条件で石英ガラスを合成した。この条件で合成した石英ガラスは、Ｘ線及びＡｒＦエキシマレーザー照射により、２１５ｎｍに吸収が生じ、放射線及び紫外線照射耐性に劣っていた。
【００５９】
比較例８
第１の熱処理でＳｉＦ4処理後Ｈ2処理を行った以外は、実施例５と同等な条件で石英ガラスを合成した。この条件で合成した石英ガラスには、Ｓｉ−Ｈ結合が生成し、Ｘ線及びＡｒＦエキシマレーザー照射により、２１５ｎｍに吸収が生じ、放射線及び紫外線照射耐性に劣っていた。
【００６０】
比較例９
第１の熱処理でＳｉＦ4処理後Ｃｌ2処理を行った以外は、実施例５と同等な条件で石英ガラスを合成した。この条件で合成した石英ガラスは、Ｃｌを３０ｐｐｍ含有しており、放射線及び紫外線照射耐性に劣っていた。
【００６１】
比較例１〜９の試料の製造条件をまとめて表１に示し、各試料の評価結果の一覧を表２に示す。表２に示すように、本発明の範囲の合成石英ガラスである実施例の試料は、耐放射線・耐紫外線用光学材料として優れた性能を持つ合成石英ガラスである。
【００６２】
【表１】

Figure 0004470054
【表２】
Figure 0004470054
【発明の効果】
本発明の方法により、放射線及び紫外線照射耐性に優れた合成石英ガラスの提供が可能となった。本発明の方法では、石英ガラス中のＯＨ基、Ｆ、Ｓｉ−Ｈ結合、酸素欠乏型欠陥及び酸素過剰型欠陥の各濃度を制御することで構造を安定化して、紫外線領域の透過率を向上させると共に、放射線及び紫外線照射耐性を高めているので、特殊な製造方法による事なく、安価で、優れた耐放射線・耐紫外線合成石英ガラスの提供が可能である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a synthetic quartz glass having excellent radiation resistance / ultraviolet resistance properties against radiation such as X-rays and irradiation of vacuum ultraviolet rays having a wavelength of 200 nm or less, such as an ArF excimer laser, and a method for producing the same.
[0002]
[Prior art]
Synthetic quartz glass is used in various optical members because it is transparent in a wide wavelength range from infrared to vacuum ultraviolet (<200 nm). Since it is used as an optical material for ultraviolet rays such as a KrF excimer laser, an attempt has been made to increase resistance by increasing the OH group concentration (see, for example, Patent Document 1).
[0003]
[Problems to be solved by the invention]
However, since OH groups exhibit absorption in the vacuum ultraviolet region, there is a problem in that the transmittance in the vacuum ultraviolet region decreases when the OH group concentration is increased. In addition, there is a problem that the transmittance is lowered due to cleavage of the OH group by generation of high energy density excimer laser or irradiation of shorter wavelength light such as X-rays to generate new defects.
[0004]
As a method for solving the problem of absorption due to OH groups, a method has been proposed in which quartz glass having a low OH group concentration is preliminarily irradiated with ultraviolet rays to actively generate defects, and the defects are removed by heat treatment (for example, Patent Documents). 2). According to this method, an improvement in resistance to ultraviolet irradiation equivalent to that irradiated in advance can be expected, but compared to irradiation for improving resistance, the irradiation with ultraviolet light for a longer time or at a higher energy density is possible. Or, resistance to ultraviolet irradiation of a shorter wavelength (high energy) is not improved. Moreover, since the ultraviolet irradiation process is required, there is a problem that the process becomes complicated and an extra cost is required.
[0005]
In addition, it has been reported that when synthetic quartz glass with a reduced OH group concentration contains fluorine (F), the transmittance in the vacuum ultraviolet region and the resistance to vacuum ultraviolet irradiation are improved (for example, non-patent literature). 1). Although the transmittance at the initial stage of irradiation is improved by containing F, the resistance to ultraviolet irradiation at a high energy density and radiation irradiation such as X-rays is not sufficient.
[0006]
[Patent Document 1]
JP 2000-7349 A (page 3)
[Patent Document 2]
Japanese Patent No. 3054412 (2nd page)
[Non-Patent Document 1]
Hagio et al., “Silica Glass as Deep UV-VUV Optical Material”, New Glass, New Glass Forum, December 2, 2002, Vol. 17, No. 4, p. 31-35
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present inventor has conducted extensive studies on the correlation between various properties of synthetic quartz glass and radiation resistance / ultraviolet resistance. As a result, OH group content, F content of synthetic quartz glass, The Si-H content and the concentration of oxygen-deficient defects and oxygen-excess defects are particularly important for radiation resistance and vacuum ultraviolet radiation resistance, and by limiting each value to a specific range, It has been found that a synthetic quartz glass excellent in ultraviolet resistance can be obtained.
[0008]
That is, the present invention has an OH group content of 2 to 50 ppm, an F content of 500 to 2000 ppm, an Si—H bond content of 1 × 10 17 ions / cm 3 or less, and oxygen-deficient defects and oxygen-rich defect concentrations. 1 × 10 16 pieces / cm 3 or less, internal transmittance at a wavelength of 163 nm is 60% or more per cm, and absorption at a wavelength of 215 nm when an ArF excimer laser is irradiated with 1 × 10 6 shots at an energy density of 10 mJ / cm 2 Synthetic quartz glass characterized by a coefficient change of 0.001 cm -1 or less, among which X-ray irradiation dose rate 2 × 10 4 C / kg · h (Rh tube, tube voltage 50 kV, tube a synthetic quartz glass absorption coefficient change in the wavelength 215nm when irradiated 2 hours with a current 50 mA) is characterized that it is 0.1 cm -1 or less, further, that containing H 2 amount is 1 × 0 is 17 / cm 3 synthetic quartz glass and wherein the or less.
[0009]
Also, in the so-called soot method in which silica fine particles obtained by flame hydrolysis of a glass forming raw material in an oxyhydrogen flame are deposited on a target to synthesize a soot body and then transparent vitrified by a subsequent heat treatment, in the oxyhydrogen flame A soot body was synthesized with a molar ratio of H 2 and O 2 (H 2 / O 2 ratio) of 2.0 to 3.0, and the soot body was heat-treated with an F element-containing gas, and then transparent vitrification was carried out to 1300 The scope of the present invention includes a method for producing the synthetic quartz glass having the physical properties and a use of the synthetic quartz glass having the physical properties as an optical member for vacuum ultraviolet rays, characterized by including a step performed at 1550 ° C.
[0010]
Hereinafter, the present invention will be described in detail.
[0011]
Since the OH groups in the synthetic quartz glass show absorption in the vacuum ultraviolet region, the transmittance in the vacuum ultraviolet region increases as the OH group content decreases. In order to obtain a sufficient transmittance in the vacuum ultraviolet region, the OH group concentration is 2 to 50 ppm, preferably 5 to 30 ppm.
[0012]
When the OH group concentration is less than 2 ppm, not only the transmittance in the vacuum ultraviolet region is lowered, but also the radiation / ultraviolet ray resistance is lowered. Although the action of such OH groups is not clear, it is considered that OH groups have the effect of stabilizing the amorphous structure of unstable quartz glass.
[0013]
Since F has an effect of improving the transmittance in the vacuum ultraviolet region, it is preferable to contain F in the synthetic quartz glass. However, when the F content is high, when the synthetic quartz glass is heat-treated by annealing and molding, the quartz glass is corroded by F and a new structural defect is generated, which may adversely affect the transmittance and resistance. In addition, Si-F bonds also increase. This bond causes distortion in the structure of the quartz glass, which makes the structure of the quartz glass unstable and deteriorates the resistance to radiation and ultraviolet rays. Therefore, the F concentration contained in the quartz glass is 500 to 2000 ppm, preferably 700 to Set to 1600 ppm.
[0014]
In general, synthetic quartz glass is synthesized using an oxyhydrogen flame, but a part of H 2 in the flame is taken into the quartz glass to generate a Si—H bond. The Si-H bond has a smaller bond energy than the ≡Si-O-Si≡ bond of quartz glass, and it can be easily cleaved by radiation and ultraviolet irradiation, causing defects, so its content is limited to a certain amount or less. Specifically, the content of Si—H bonds is 1 × 10 17 pieces / cm 3 or less, preferably 0.5 × 10 17 pieces / cm 3 or less. High synthetic quartz glass.
[0015]
Synthetic quartz glass has a structure in which ≡Si—O—Si≡ bonds are connected at random, but depending on the manufacturing conditions, defects lacking oxygen atoms (O) (oxygen-deficient defects, ≡Si—Si≡), O-excess defects (oxygen-rich defects, ≡Si—O—O—Si≡) are generated. These structures have a smaller binding energy than the ≡Si—O—Si≡ bond, and are easily cleaved by irradiation with radiation / ultraviolet rays to reduce radiation / ultraviolet irradiation resistance. Further, these defects distort adjacent ≡Si—O—Si≡ bonds, destabilize the structure of quartz glass, and adversely affect radiation / ultraviolet irradiation resistance.
[0016]
Therefore, it is necessary to limit the content of these defects to a certain amount or less, and the content of oxygen deficient defects and oxygen excess defects is 1 × 10 16 pieces / cm 3 or less, preferably 0.5 × 10 6. It may be 16 pieces / cm 3 or less.
[0017]
Oxygen-rich defects that adversely affect radiation / ultraviolet irradiation resistance are suppressed by synthesis under conditions of excess H 2 . At this time, if H 2 becomes excessive, oxygen deficient defects are generated and radiation / ultraviolet light resistance is lowered. Therefore, control of H 2 concentration during synthesis is important. A part of the excess H 2 is taken into the quartz glass, but this H 2 reacts with a defect caused by radiation / ultraviolet irradiation to easily generate a Si—H bond. As already described, the Si—H bond adversely affects the radiation / ultraviolet ray resistance. In addition, due to the reducing action of H 2 taken into the quartz glass, oxygen deficient defects are newly generated, and the radiation / ultraviolet irradiation resistance is lowered.
[0018]
Accordingly, it has been found that it is important to limit the H 2 content in the quartz glass to a certain amount or less. In order to obtain the synthetic quartz glass having high radiation / ultraviolet irradiation resistance of the present invention, the content of H 2 is preferably 1 × 10 17 pieces / cm 3 or less.
[0019]
Normally, as the H 2 concentration in the synthesis atmosphere increases, the H 2 content in the quartz glass also increases accordingly. Therefore, management of the H 2 concentration during synthesis is important for the production of radiation-resistant and ultraviolet-resistant synthetic quartz glass. .
[0020]
By combining the above-described conditions, the synthetic quartz glass of the present invention has an internal transmittance at a wavelength of 163 nm of 60% or more per cm, and an ArF excimer laser is irradiated with 1 × 10 6 shots at an energy density of 10 mJ / cm 2 . The change in absorption coefficient at a wavelength of 215 nm is 0.001 cm -1 or less, and X-ray irradiation is performed at an irradiation dose rate of 2 × 10 4 C / kg · h (Rh tube, tube voltage 50 kV, tube current 50 mA) for 2 hours. The change in absorption coefficient at a wavelength of 215 nm when irradiated is 0.1 cm −1 or less, and the radiation resistance and ultraviolet resistance are excellent.
[0021]
Since metal impurities (alkali metal, alkaline earth metal, transition metal, and other metals) absorb in the vacuum ultraviolet region, the content is preferably as low as possible. When the metal impurity content is increased, not only the transmittance in the vacuum ultraviolet region is lowered, but also defects due to the metal impurities are generated by radiation / ultraviolet irradiation, and a desired resistance cannot be obtained. As a result of examining the metal impurities and their contents affecting the resistance, alkali metals such as Li, Na and K, alkaline earth metals such as Mg and Ca, Ti, Cr, Fe, Ni, Cu, Zr, Mo and the like It can be seen that transition metals and other metals such as Al decrease the radiation / ultraviolet irradiation resistance. From the relationship between the content and the resistance, in order to obtain the synthetic quartz glass having high radiation / ultraviolet irradiation resistance of the present invention, the metal The total amount of impurities is preferably 50 ppb or less, more preferably 20 ppb or less, and particularly preferably 10 ppb or less.
[0022]
In synthetic quartz glass, SiCl 4 is generally used as a raw material for ease of handling and cost. Therefore, there is a possibility that Cl remains in the synthesized quartz glass, and this Cl is considered to exist in the form of ≡Si—Cl by directly bonding to Si inside the glass. Since this ≡Si—Cl bond is easily cleaved by radiation / ultraviolet irradiation and causes defects, it is preferable that the Cl content is as low as possible. When the Cl content is 10 ppm or less, sufficiently satisfactory performance as radiation-resistant / ultraviolet-resistant synthetic quartz glass can be obtained, and more preferably 1 ppm or less, and higher performance can be obtained.
[0023]
Next, the manufacturing method of the synthetic quartz glass of this invention is demonstrated. The method for producing synthetic quartz glass excellent in radiation resistance / ultraviolet resistance of the present invention is preferably a soot method from the viewpoint of operational operability, productivity, quality stability, cost and the like. Hereinafter, the soot method will be described in detail.
[0024]
In the soot method, for example, a raw material such as SiCl 4 is supplied from the center of a quartz glass burner having a multi-tube structure, and H 2 and O 2 are supplied from the outer tube to flame-hydrolyze the raw material to produce silica fine particles. Synthesize. By making the ratio of H 2 and O 2 at this time H 2 excessive from the theoretical amount 2.0, the generation of oxygen-excess defects can be suppressed. However, if the ratio exceeds 3.0, H 2 is excessive, and the concentration of H 2 and oxygen-deficient defects cannot be maintained in an appropriate range. Therefore, the ratio of H 2 to O 2 is 2.0-3. 0.0, preferably in the range of 2.2 to 2.6.
[0025]
Since the silica fine particles contain a large amount of OH groups, the first heat treatment is performed in a reducing gas-containing atmosphere to reduce the OH group concentration to an appropriate range. The conditions for the first heat treatment are not particularly limited as long as the desired OH group concentration can be obtained. In the first heat treatment, in order to contain F, it is preferable to include a treatment in an F-containing gas atmosphere in a temperature range of 500 to 1100 ° C., preferably 600 to 800 ° C. The treatment time is preferably 1 to 10 hours.
[0026]
In the first heat treatment, treatment with a gas not containing F and treatment with an F-containing gas may be used in combination, or F-containing gas treatment may be performed alone. When the treatment temperature with the F-containing gas is higher than 1100 ° C., not only the ≡Si—F bond becomes excessive and the structure of the quartz glass becomes unstable, but also the ≡Si—O—Si≡ bond between the F-containing gas and the quartz glass This reaction is promoted to generate reduced defects. On the other hand, when the treatment is performed at a temperature lower than 500 ° C., the reaction between F and OH groups becomes insufficient, and the desired concentration F is not contained.
[0027]
Examples of the gas containing F include SiF 4 and the like, and examples of the gas not containing F include Cl 2 and CO.
[0028]
Subsequent to the first heat treatment, a second heat treatment is performed in a temperature range of 1300 ° C. to 1550 ° C. to form a transparent glass. If the second heat treatment is lower than 1300 ° C., a transparent quartz glass cannot be obtained. Conversely, when the treatment is performed at a temperature higher than 1550 ° C., transparent vitrification proceeds rapidly and the structure becomes unstable, so that desired performance cannot be obtained. As preferable treatment conditions, heating may be performed at 1350 to 1450 ° C. for 1 to 10 hours.
[0029]
Examples of the atmosphere for performing the second heat treatment include an inert gas atmosphere such as He, an atmosphere containing oxygen in an inert gas, and the like. A gas containing oxygen is preferable in terms of suppressing the production of oxygen.
[0030]
The raw material is preferably SiCl 4 because it is easy to handle and obtain, and is inexpensive. However, the present invention is not particularly limited to this. When a Cl-containing silicon compound such as SiCl 4 is used as a raw material, the metal impurities are removed from the system as chlorides, so that the metal impurity content can be reduced to 50 ppb or less without any special treatment.
[0031]
When a Cl-containing material such as SiCl 4 is used as a raw material, Cl remains in the soot, but this residual Cl is removed together with the OH group during the first heat treatment, so that a special treatment is performed. In addition, the Cl concentration can be reduced to 10 ppm or less.
[0032]
In addition, general manufacturing conditions of the conventional soot method can be applied to manufacturing conditions other than those specified in the present invention.
[0033]
If synthetic quartz glass is manufactured under the conditions described above, it is possible to obtain radiation- and ultraviolet-resistant synthetic quartz glass that is inexpensive and has excellent radiation / ultraviolet irradiation resistance by a general-purpose manufacturing method and manufacturing equipment. .
[0034]
When the quartz glass synthesized in this way is processed and polished into a predetermined shape and used as an optical material for vacuum ultraviolet rays, it exhibits excellent resistance to vacuum ultraviolet irradiation and is particularly suitable for use as an optical material for vacuum ultraviolet rays. Yes.
[0035]
【Example】
The present invention will be specifically described by the following examples, but the present invention is not limited to these examples. In the following examples, He was used as the dilution gas.
[0036]
Example 1
A synthetic quartz glass ingot was produced by the soot method using SiCl 4 as a raw material. The raw material was supplied from the central tube of the quartz glass burner, and H 2 and O 2 were supplied from the outer tube of the burner so that the H 2 / O 2 ratio (molar ratio) was 2.3 to synthesize the soot body. . This soot body was subjected to heat treatment at 1100 ° C. for 2 hours in an atmosphere of 10 vol% (volume%) Cl 2 gas (remaining He) as a first heat treatment, and then in an atmosphere of 0.1 vol% SiF 4 gas (remaining He). Heat treatment was performed at 600 ° C. for 2 hours. The soot body subjected to the first heat treatment was heat-treated at 1500 ° C. for 5 hours in a He gas atmosphere to obtain a synthetic quartz glass ingot.
[0037]
Subsequently, an ingot impregnated with H 2 was obtained by treatment in a 100% H 2 atmosphere at 500 ° C. for 5 hours. In the following examples and comparative examples, a test piece having a thickness of 10 mm was cut out from the obtained ingot and used as an evaluation sample.
[0038]
Example 2
A synthetic quartz glass ingot was obtained in the same manner as in Example 1 except that the H 2 / O 2 ratio was 2.3 and the H 2 impregnation treatment was not performed.
[0039]
Example 3
A synthetic quartz glass ingot was produced by the soot method using SiCl 4 as a raw material. The soot body was synthesized by supplying the raw material from the central tube of the quartz glass burner and supplying H 2 and O 2 from the outer tube of the burner so that the H 2 / O 2 ratio was 2.2. This soot body was subjected to heat treatment at 600 ° C. for 5 hours in a 1 vol% SiF 4 gas atmosphere as a first heat treatment. Thereafter, as a second heat treatment, a heat treatment was performed at 1500 ° C. for 5 hours in a He gas atmosphere to obtain a synthetic quartz glass ingot. The obtained ingot was treated in a 100% H 2 atmosphere at 500 ° C. for 5 hours, and impregnated with H 2 to obtain a synthetic quartz glass ingot.
[0040]
Example 4
A synthetic quartz glass ingot was produced by the soot method using SiCl 4 as a raw material. The soot body was synthesized by supplying the raw material from the central tube of the quartz glass burner and supplying H 2 and O 2 from the outer tube of the burner so that the H 2 / O 2 ratio was 2.2. This soot body was subjected to heat treatment at 600 ° C. for 5 hours in a 1 vol% SiF 4 gas atmosphere as a first heat treatment. Thereafter, as a second heat treatment, a heat treatment was performed at 1500 ° C. for 5 hours in a He gas atmosphere to obtain a synthetic quartz glass ingot.
[0041]
Example 5
A synthetic quartz glass ingot was produced by the soot method using SiCl 4 as a raw material. The soot body was synthesized by supplying the raw material from the central tube of the quartz glass burner and supplying H 2 and O 2 from the outer tube of the burner so that the H 2 / O 2 ratio was 2.2. This soot body was heat-treated at 800 ° C. for 5 hours in a 0.1 vol% SiF 4 gas atmosphere as a first heat treatment. Thereafter, as a second heat treatment, a heat treatment was performed at 1500 ° C. for 5 hours in a 10% O 2 gas atmosphere to obtain a synthetic quartz glass ingot.
[0042]
Example 6
A synthetic quartz glass ingot was obtained in the same manner as in Example 5 except that the H 2 / O 2 ratio was 2.6 and the first heat treatment was 1000 ° C.
[0043]
Example 7
A synthetic quartz glass ingot was produced by the soot method using SiCl 4 as a raw material. The soot body was synthesized by supplying the raw material from the central tube of the quartz glass burner and supplying H 2 and O 2 from the outer tube of the burner so that the H 2 / O 2 ratio was 2.2. This soot body was subjected to heat treatment at 1100 ° C. for 5 hours in a 10 vol% CO gas atmosphere as a first heat treatment, and then at 600 ° C. for 2 hours in a 0.1 vol% SiF 4 gas atmosphere. The soot body subjected to the first heat treatment was heat-treated at 1500 ° C. for 5 hours in a He gas atmosphere to obtain a synthetic quartz glass ingot.
[0044]
The production conditions of the samples of Examples 1 to 7 are collectively shown in Table 1, and a list of the evaluation results of each sample is shown in Table 2.
[0045]
In addition, the determination method of the content component of each sample is as follows.
[0046]
The OH group content was quantified by IR measurement from the absorption of about 2.7 μm.
[0047]
Si-H and H 2 contents were quantified by Raman spectroscopy. Peaks corresponding to Si-H and H 2, respectively, appear and about 4150cm -1 to approximately 2250 cm -1. The Si—H and H 2 contents were calculated from the ratio between the area intensity of this peak and the area intensity of the peak at about 800 cm −1 due to the basic structure of quartz glass.
[0048]
The oxygen-deficient defect was evaluated by measuring the VUV spectrum from the absorption coefficient of 163 nm, and the oxygen-rich defect by measuring the VUV and UV spectra and calculating the concentration from the absorption coefficients of 185 nm and 326 nm.
[0049]
The F content was determined by ion chromatography after melting the obtained quartz glass with alkali. The metal impurity content was determined by ICP mass spectrometry. The Cl content was quantified by a fluorescent X-ray measurement method using a calibration curve method.
[0050]
An ArF excimer laser was irradiated with 1 × 10 6 pulses at an energy density of 10 mJ / cm 2 per pulse, an absorption coefficient of 215 nm was determined from UV spectra before and after irradiation, and laser resistance was evaluated.
[0051]
X-ray irradiation dose rate 2 × 10 4 C / kg · h (X-ray irradiation test was performed with a sample set on a fluorescent X-ray apparatus. Irradiation conditions were Rh tube, tube voltage 50 kV, tube current 50 mA) Was irradiated for 2 hours, the absorption coefficient of 215 nm before and after irradiation was determined, and the radiation resistance was evaluated.
[0052]
Comparative Example 1
A synthetic quartz glass ingot was obtained under the same conditions as in Example 5 except that the H 2 / O 2 ratio was 1.8. This sample had an oxygen excess type defect concentration of 2 × 10 16 pieces / cm 3 . The initial transmittance of this sample was 60%, but the resistance to radiation and ultraviolet rays was poor.
[0053]
Comparative Example 2
A synthetic quartz glass ingot was obtained under the same conditions as in Example 5 except that the H 2 / O 2 ratio was 3.2. This sample had an oxygen-deficient defect concentration of 5 × 10 16 pieces / cm 3 . The initial transmittance of this sample was 85%, but the resistance to radiation and ultraviolet rays was poor.
[0054]
Comparative Example 3
A synthetic quartz glass ingot was obtained under the same conditions as in Example 5 except that the first heat treatment was performed at 400 ° C. The OH group and F content of this sample were 80 ppm and 550 ppm, respectively. The transmittance of this sample was as low as 45%. Further, when irradiated with X-rays and excimer laser, absorption occurred at 215 nm, and the resistance was poor.
[0055]
Comparative Example 4
Under the same conditions as in Example 5, except that the first heat treatment was performed in a 100% N 2 atmosphere at 1300 ° C. for 5 hours and then in a 0.1 vol% SiF 4 atmosphere at 1100 ° C. for 5 hours. A synthetic quartz glass ingot was obtained. The OH group and F contents of this sample were 1 ppm and 1850 ppm, respectively, and the initial transmittance was as high as 95%, but the radiation irradiation resistance was poor.
[0056]
Comparative Example 5
A synthetic quartz glass ingot was obtained under the same conditions as in Example 5 except that the first heat treatment was performed at 1200 ° C. The OH group and F content of this sample were 5 ppm and 2250 ppm, respectively, and the oxygen-deficient defect concentration was 7 × 10 16 pieces / cm 3 . The initial transmittance was as high as 80%, but the resistance to radiation and ultraviolet irradiation was poor.
[0057]
Comparative Example 6
Quartz glass was synthesized under the same conditions as in Example 5 except that the second heat treatment was performed at 1250 ° C. Under this condition, transparent quartz glass could not be obtained.
[0058]
Comparative Example 7
Quartz glass was synthesized under the same conditions as in Example 5 except that the second heat treatment was performed at 1650 ° C. The quartz glass synthesized under these conditions was absorbed at 215 nm by X-ray and ArF excimer laser irradiation, and was inferior in radiation and ultraviolet irradiation resistance.
[0059]
Comparative Example 8
Quartz glass was synthesized under the same conditions as in Example 5 except that the first heat treatment was followed by the SiF 4 treatment and the H 2 treatment. In the quartz glass synthesized under these conditions, a Si—H bond was generated, and absorption at 215 nm was caused by X-ray and ArF excimer laser irradiation, which was inferior in resistance to radiation and ultraviolet irradiation.
[0060]
Comparative Example 9
Quartz glass was synthesized under the same conditions as in Example 5 except that the first heat treatment was followed by the SiF 4 treatment followed by the Cl 2 treatment. The quartz glass synthesized under these conditions contained 30 ppm of Cl and was inferior in radiation and ultraviolet irradiation resistance.
[0061]
The manufacturing conditions of the samples of Comparative Examples 1 to 9 are collectively shown in Table 1, and a list of evaluation results of each sample is shown in Table 2. As shown in Table 2, a sample of an example which is a synthetic quartz glass within the scope of the present invention is a synthetic quartz glass having excellent performance as a radiation-resistant / ultraviolet-resistant optical material.
[0062]
[Table 1]
Figure 0004470054
[Table 2]
Figure 0004470054
【The invention's effect】
According to the method of the present invention, it is possible to provide a synthetic quartz glass excellent in radiation and ultraviolet irradiation resistance. In the method of the present invention, the structure is stabilized by controlling the concentrations of OH groups, F, Si—H bonds, oxygen-deficient defects and oxygen-rich defects in quartz glass, and the transmittance in the ultraviolet region is improved. In addition, since the radiation and ultraviolet irradiation resistance is enhanced, it is possible to provide an inexpensive radiation-resistant / ultraviolet-resistant synthetic quartz glass at low cost without using a special manufacturing method.

Claims (7)

ＯＨ基含有量が２〜５０ｐｐｍ、Ｆ含有量が５００〜２０００ｐｐｍ、Ｓｉ−Ｈ結合の含有量が１×１０１７個／ｃｍ３以下、酸素欠乏型欠陥及び酸素過剰型欠陥の濃度が共に１×１０１６個／ｃｍ３以下、波長１６３ｎｍにおける内部透過率が１ｃｍあたり６０％以上かつ、ＡｒＦエキシマレーザーをエネルギー密度１０ｍＪ／ｃｍ２で１×１０６ショット照射した時の波長２１５ｎｍの吸収係数変化が０．００１ｃｍ−１以下である合成石英ガラス。The OH group content is 2 to 50 ppm, the F content is 500 to 2000 ppm, the Si—H bond content is 1 × 10 17 atoms / cm 3 or less, and the concentration of oxygen-deficient defects and oxygen-rich defects is 1 ×. 10 16 pieces / cm 3 or less, internal transmittance at a wavelength of 163 nm is 60% or more per cm, and the absorption coefficient change at a wavelength of 215 nm is 0 when an ArF excimer laser is irradiated with 1 × 10 6 shots at an energy density of 10 mJ / cm 2. Synthetic quartz glass which is 0.001 cm −1 or less. 請求項１記載の合成石英ガラスにおいて、Ｘ線を照射線量率２×１０４Ｃ／ｋｇ・ｈ（Ｒｈ管球、管電圧５０ｋＶ、管電流５０ｍＡ）で２時間照射した時の波長２１５ｎｍにおける吸収係数変化が０．１ｃｍ−１以下である事を特徴とする請求項１記載の合成石英ガラス。The absorption coefficient at a wavelength of 215 nm when X-rays are irradiated for 2 hours at an irradiation dose rate of 2 × 10 4 C / kg · h (Rh tube, tube voltage 50 kV, tube current 50 mA). The synthetic quartz glass according to claim 1, wherein the change is 0.1 cm -1 or less. 請求項１又は請求項２に記載の合成石英ガラスにおいて、Ｈ２含有量が１×１０１７個／ｃｍ３以下である事を特徴とする合成石英ガラス。In the synthetic quartz glass according to claim 1 or claim 2, the synthetic quartz glass and wherein the containing H 2 amount is 1 × 10 17 / cm 3 or less. 請求項１から請求項３のいずれかに記載の合成石英ガラスにおいて、金属不純物含有量の総和が５０ｐｐｂ以下かつＣｌ含有量が１０ｐｐｍ以下である事を特徴とする合成石英ガラス。The synthetic quartz glass according to any one of claims 1 to 3, wherein the total content of metal impurities is 50 ppb or less and the Cl content is 10 ppm or less. ガラス形成原料を、酸水素火炎中で火炎加水分解し、得られたシリカ微粒子をターゲット上に堆積させ、得られた多孔質シリカ母材（スート体）を加熱して透明ガラス化する、スート法における合成石英ガラスの製造方法において、少なくとも以下の工程を含んでなる請求項１から請求項４のいずれかに記載の合成石英ガラスの製造方法。
（ａ）酸水素火炎におけるＨ２とＯ２とのモル比（Ｈ２／Ｏ２比）を２．０〜３．０としてスート体を合成する工程
（ｂ）得られたスート体を、６００〜１０００℃の温度で、１〜１０時間フッ素元素含有ガス雰囲気で処理する工程
（ｃ）処理したスート体を、１３００℃〜１５５０℃の温度で透明ガラス化する工程。A soot method in which a glass forming raw material is flame-hydrolyzed in an oxyhydrogen flame, the obtained silica fine particles are deposited on a target, and the resulting porous silica base material (soot body) is heated to form a transparent glass. The method for producing synthetic quartz glass according to claim 1, comprising at least the following steps.
The molar ratio (H 2 / O 2 ratio) synthesizing a soot body as 2.0-3.0 step (b) the resulting soot body of H 2 and O 2 in (a) oxyhydrogen flame, 600 A step of treating in a fluorine element-containing gas atmosphere at a temperature of ˜1000 ° C. for 1 to 10 hours (c) A step of transparent vitrification of the treated soot body at a temperature of 1300 ° C. to 1550 ° C. 透明ガラス化をＯ２ガス含有雰囲気下で行う事を特徴とする請求項５記載の合成石英ガラスの製造方法。6. The method for producing synthetic quartz glass according to claim 5, wherein transparent vitrification is performed in an atmosphere containing O 2 gas. 請求項１から請求項４のいずれかに記載の合成石英ガラスを加工してなる真空紫外線用光学素材。An optical material for vacuum ultraviolet rays obtained by processing the synthetic quartz glass according to any one of claims 1 to 4.
JP2003208904A 2003-08-26 2003-08-26 Synthetic quartz glass and manufacturing method thereof Expired - Fee Related JP4470054B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2003208904A JP4470054B2 (en) 2003-08-26 2003-08-26 Synthetic quartz glass and manufacturing method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2003208904A JP4470054B2 (en) 2003-08-26 2003-08-26 Synthetic quartz glass and manufacturing method thereof

Publications (2)

Publication Number Publication Date
JP2005067913A JP2005067913A (en) 2005-03-17
JP4470054B2 true JP4470054B2 (en) 2010-06-02

Family

ID=34402008

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2003208904A Expired - Fee Related JP4470054B2 (en) 2003-08-26 2003-08-26 Synthetic quartz glass and manufacturing method thereof

Country Status (1)

Country Link
JP (1) JP4470054B2 (en)

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7964522B2 (en) 2006-08-31 2011-06-21 Corning Incorporated F-doped silica glass and process of making same
CN101511744B (en) 2006-09-11 2012-11-14 东曹株式会社 Fused quartz glass and process for producing the same
US9067814B2 (en) * 2009-01-19 2015-06-30 Shin-Etsu Chemical Co., Ltd. Method of producing synthetic quartz glass for excimer laser
EP2508491B1 (en) * 2011-04-05 2017-01-11 Heraeus Quarzglas GmbH & Co. KG A synthetic silica glass, especially for the cladding of an optical fiber
US9067823B2 (en) 2011-04-20 2015-06-30 Heraeus Quarzglas Gmbh & Co. Kg Synthetic silica glass, especially for the cladding of an optical fiber and a manufacturing method for the synthetic silica glass
TWI720090B (en) 2015-12-18 2021-03-01 德商何瑞斯廓格拉斯公司 Preparation of carbon-doped silicon dioxide granulate as an intermediate in the preparation of quartz glass
TWI813534B (en) 2015-12-18 2023-09-01 德商何瑞斯廓格拉斯公司 Preparation of quartz glass bodies with dew point monitoring in the melting oven
US11492285B2 (en) 2015-12-18 2022-11-08 Heraeus Quarzglas Gmbh & Co. Kg Preparation of quartz glass bodies from silicon dioxide granulate
US11236002B2 (en) 2015-12-18 2022-02-01 Heraeus Quarzglas Gmbh & Co. Kg Preparation of an opaque quartz glass body
CN108698885A (en) 2015-12-18 2018-10-23 贺利氏石英玻璃有限两合公司 The promotion of silicone content in prepared by 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
EP3390304B1 (en) 2015-12-18 2023-09-13 Heraeus Quarzglas GmbH & Co. KG Spray granulation of silicon dioxide in the production of quartz glass
JP7048053B2 (en) 2015-12-18 2022-04-05 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 quartz glass in a multi-chamber furnace
WO2017103153A1 (en) * 2015-12-18 2017-06-22 Heraeus Quarzglas Gmbh & Co. Kg Glass fibers and preforms made of quartz glass having low oh, cl, and al content
DE102018211234A1 (en) 2018-07-06 2020-01-09 Carl Zeiss Smt Gmbh Substrate for a reflective optical element

Also Published As

Publication number Publication date
JP2005067913A (en) 2005-03-17

Similar Documents

Publication Publication Date Title
JP4470054B2 (en) Synthetic quartz glass and manufacturing method thereof
JP4470479B2 (en) Synthetic quartz glass for optical members and method for producing the same
JP4492123B2 (en) Silica glass
TWI393689B (en) Component of quartz glass for use in semiconductor manufacture and method for producing the same
EP1125897B1 (en) Synthetic quartz glass and method for preparing the same
JP3893816B2 (en) Synthetic quartz glass and manufacturing method thereof
EP2495220A1 (en) Optical member for deep ultraviolet and process for producing same
JP4066632B2 (en) Synthetic quartz glass optical body and manufacturing method thereof
JP2001146434A (en) Optical material for ultraviolet ray and method for producing the material
JP2001048571A (en) Quartz glass excellent in transmission of short wavelength light, and its production
JP2003081654A (en) Synthetic quartz glass, and production method therefor
JP2005298330A (en) Synthetic quartz glass and its manufacturing method
JP4946960B2 (en) Synthetic quartz glass and manufacturing method thereof
JP3277719B2 (en) Synthetic quartz glass for transmitting ultraviolet light and method for producing the same
JP2005170706A (en) Ultraviolet-absorbing synthetic quartz glass and method for producing the same
JP4213413B2 (en) Highly homogeneous synthetic quartz glass for vacuum ultraviolet light, method for producing the same, and mask substrate for vacuum ultraviolet light using the same
JP3336761B2 (en) Method for producing synthetic quartz glass for light transmission
JP4213412B2 (en) Synthetic quartz glass for vacuum ultraviolet light, manufacturing method thereof, and mask substrate for vacuum ultraviolet light using the same
JP4085633B2 (en) Synthetic quartz glass for optical components
JP4166456B2 (en) Synthetic quartz glass for vacuum ultraviolet light, manufacturing method thereof, and mask substrate for vacuum ultraviolet light using the same
JP4093393B2 (en) Highly homogeneous synthetic quartz glass for vacuum ultraviolet light, method for producing the same, and mask substrate for vacuum ultraviolet light using the same
JP2002053331A (en) SYNTHETIC QUARTZ GLASS FOR ArF EXCIMER LASER, ITS MANUFACTURING METHOD AND USE THEREOF
JP4228493B2 (en) Synthetic quartz glass
JP2005239474A (en) Synthetic quartz glass having radiation resistance and ultraviolet ray resistance, its manufacturing method, and its use
JP2003201125A (en) Synthetic quartz glass and its manufacturing method

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20060620

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20080701

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20090915

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20091116

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20100209

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20100216

FPAY Renewal fee payment (prs date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130312

Year of fee payment: 3

R150 Certificate of patent (=grant) or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (prs date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130312

Year of fee payment: 3

FPAY Renewal fee payment (prs date is renewal date of database)

Free format text: PAYMENT UNTIL: 20140312

Year of fee payment: 4

LAPS Cancellation because of no payment of annual fees