JP3674793B2 - Method for producing quartz glass optical member for ultraviolet laser - Google Patents
Method for producing quartz glass optical member for ultraviolet laser Download PDFInfo
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- JP3674793B2 JP3674793B2 JP30643895A JP30643895A JP3674793B2 JP 3674793 B2 JP3674793 B2 JP 3674793B2 JP 30643895 A JP30643895 A JP 30643895A JP 30643895 A JP30643895 A JP 30643895A JP 3674793 B2 JP3674793 B2 JP 3674793B2
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 title claims description 106
- 230000003287 optical effect Effects 0.000 title claims description 28
- 238000004519 manufacturing process Methods 0.000 title claims description 24
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 106
- 239000001257 hydrogen Substances 0.000 claims description 94
- 229910052739 hydrogen Inorganic materials 0.000 claims description 94
- 238000000034 method Methods 0.000 claims description 33
- 238000000265 homogenisation Methods 0.000 claims description 17
- 239000012298 atmosphere Substances 0.000 claims description 9
- 239000000377 silicon dioxide Substances 0.000 claims description 9
- 239000000758 substrate Substances 0.000 claims description 7
- 239000010419 fine particle Substances 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 6
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 claims description 6
- 229910052753 mercury Inorganic materials 0.000 claims description 6
- 239000004071 soot Substances 0.000 claims description 6
- 150000003377 silicon compounds Chemical class 0.000 claims description 4
- 238000000151 deposition Methods 0.000 claims description 3
- 239000011521 glass Substances 0.000 claims description 3
- 230000003301 hydrolyzing effect Effects 0.000 claims description 3
- YZCKVEUIGOORGS-OUBTZVSYSA-N Deuterium Chemical compound [2H] YZCKVEUIGOORGS-OUBTZVSYSA-N 0.000 claims description 2
- YZCKVEUIGOORGS-IGMARMGPSA-N Protium Chemical compound [1H] YZCKVEUIGOORGS-IGMARMGPSA-N 0.000 claims description 2
- 230000002829 reductive effect Effects 0.000 claims description 2
- 238000001228 spectrum Methods 0.000 claims description 2
- 229910052724 xenon Inorganic materials 0.000 claims description 2
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 claims description 2
- 230000007547 defect Effects 0.000 description 18
- 238000002834 transmittance Methods 0.000 description 15
- 238000001069 Raman spectroscopy Methods 0.000 description 7
- 238000000137 annealing Methods 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 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 4
- 206010040925 Skin striae Diseases 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 239000005049 silicon tetrachloride Substances 0.000 description 4
- 238000010521 absorption reaction Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 230000007062 hydrolysis Effects 0.000 description 3
- 238000006460 hydrolysis reaction Methods 0.000 description 3
- 238000001459 lithography Methods 0.000 description 3
- BFXIKLCIZHOAAZ-UHFFFAOYSA-N methyltrimethoxysilane Chemical compound CO[Si](C)(OC)OC BFXIKLCIZHOAAZ-UHFFFAOYSA-N 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910003902 SiCl 4 Inorganic materials 0.000 description 2
- 239000000460 chlorine Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- 230000005298 paramagnetic effect Effects 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 238000004566 IR spectroscopy Methods 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- OYFJQPXVCSSHAI-QFPUQLAESA-N enalapril maleate Chemical compound OC(=O)\C=C/C(O)=O.C([C@@H](C(=O)OCC)N[C@@H](C)C(=O)N1[C@@H](CCC1)C(O)=O)CC1=CC=CC=C1 OYFJQPXVCSSHAI-QFPUQLAESA-N 0.000 description 1
- 230000005284 excitation Effects 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
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000005304 optical glass Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- -1 silicon halides Chemical class 0.000 description 1
- 238000002798 spectrophotometry method Methods 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- LFQCEHFDDXELDD-UHFFFAOYSA-N tetramethyl orthosilicate Chemical compound CO[Si](OC)(OC)OC LFQCEHFDDXELDD-UHFFFAOYSA-N 0.000 description 1
- 239000003039 volatile agent Substances 0.000 description 1
- 235000012431 wafers Nutrition 0.000 description 1
- 238000004857 zone melting Methods 0.000 description 1
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- C03B19/1453—Thermal after-treatment of the shaped article, e.g. dehydrating, consolidating, sintering
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- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B19/00—Other methods of shaping glass
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- C03B19/1415—Reactant delivery systems
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- 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
- C03C23/00—Other surface treatment of glass not in the form of fibres or filaments
- C03C23/0005—Other surface treatment of glass not in the form of fibres or filaments by irradiation
- C03C23/002—Other surface treatment of glass not in the form of fibres or filaments by irradiation by ultraviolet light
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- 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
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- 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
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
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- 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
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- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2207/00—Glass deposition burners
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- C03B2207/32—Non-halide
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- 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
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- C03C2203/00—Production processes
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Description
【０００１】
【発明の属する技術分野】
本発明は、酸水素炎による合成石英ガラス製造時に発生する水素起因欠陥若しくは高温水素処理によって生じる水素起因欠陥を除去し、波長１９３ｎｍのＡｒＦエキシマレーザ、波長２１３ｎｍのＹＡＧレーザの５倍高調波に対して優れた安定性を有する紫外線レーザ用石英ガラス光学部材を提供することにあり、特にこれらのレーザを光源とする露光装置の光学系を構成するのに好適な、例えば露光光源としてレーザ光を用いた露光装置を構成し得る紫外線レーザ用石英ガラス光学部材に関する。
【０００２】
【従来の技術】
近年、ＬＳＩの高集積化に伴い、ウエーハ上に集積回路パターンを描画する光リソグラフィ技術においてもサブミクロン単位の描画技術が要求されており、この為より微細な線幅描画を行う為に、露光系の光源の短波長化が進められてきている。
例えばリソグラフィ用ステッパの光源は、従来のＧ線（４３６ｎｍ）、ｉ線（３６５ｎｍ）から波長２４８ｎｍのＫｒＦエキシマレーザが用いられてきており、特に最近では前記ＫｒＦエキシマレーザから波長が更に短いＡｒＦエキシマレーザ（１９３ｎｍ）やＹＡＧレーザ５倍高調波（２１３ｎｍ）によるレーザ光源による露光の検討が進んでいる。
【０００３】
一方前記ｉ線（３６５ｎｍ）より短い短波長紫外線域では、従来用いられてきた多成分系光学ガラスでは十分なる光透過性が得られない為に、石英ガラス、それも紫外線吸収を極力低減するために、不純物含有量の少ない高純度合成石英ガラスを用いている。
しかしながら合成石英ガラスの純度を向上させて紫外線レーザの透過率を向上させる方法は、ある程度効果はあるものの、エキシマレーザ光が、寿命が２０ｎ秒程度のパルス光である為に、通常の水銀ランプ等から放射される紫外線に比較して時間当たりのエネルギーが非常に高いために、ガラスに加わる負荷が極めて大きく、このため前記レーザ光の長期照射によりダメージを受けやすい。
かかる欠点を解消するために、本出願人は前記石英ガラス体中に水素ガスをドープ、具体的には水素ガスを１０17ｃｍ3以上含有させた技術を提案している。（ＵＳＰ５，０８６，３５２他）
【０００４】
【発明が解決しようとする課題】
さて最近のＬＳＩの更なる高集積化の結果、波長248nmのKrFエキシマレーザから波長が更に短いArFエキシマレーザ(193nm)やYAGレーザ5倍高調波(213nm)による露光の検討が進んでいる。
これらのレーザ光源ではKrFエキシマレーザに比べて波長が短いため、光のエネルギーが更に大きく、従来に増して大きなダメージを石英ガラスに対して与える。この為エネルギーの高いArFエキシマレーザやYAG5倍高調はレーザに対する十分なレーザ耐性を与えるにはより高濃度の水素が必要となる。
しかしながら特開平6-166528号に示されるように、合成石英ガラス成長時に石英ガラス中にドープされる水素、あるいは後工程として合成石英ガラスに600℃以上の温度でドープされた水素は、石英ガラスに還元性の欠陥をもたらし、これがエキシマレーザ照射開始直後から波長215nmに吸収を持つE*センターと呼ばれる常磁性欠陥を生じさせる為に、水素をドープするために最も効率の良い石英ガラスの成長時に水素をドープするという方法が用いられない。
そしてこのE*センターは、ＫｒＦレーザでは波長が長いために問題とならないが、波長１９３ｎｍのＡｒＦエキシマレーザ若しくは波長２１３ｎｍのＹＡＧレーザの５倍高調波では前記E*センターに起因する常磁性欠陥が問題となる。
【０００５】
この為本出願人は、先に出発母材の水素起因還元性欠陥を除去する為に、１５００℃以下の温度領域で、酸化熱処理をした後、６００℃以下、好ましくは４００℃以下の温度で水素をドープする技術を提案している。（特開平６−１６６５２８号）
しかしながら６００℃以下、好ましくは４００℃以下の低温で、必要な高濃度の水素をドープすることは可能であるが、非常に時間がかかり非効率である。
【０００６】
本発明はかかる従来技術の欠点に鑑み、４００℃以上、好ましくは６００℃以上の温度で水素をドープした場合においても、容易に水素起因還元性欠陥を除去することの出来る紫外線レーザ用石英ガラス光学部材の製造方法を提供することを目的とする。
本発明の他の目的が、酸水素炎による合成石英ガラス製造時に発生する水素起因欠陥若しくは高温水素処理によって生じる水素起因欠陥を除去し、紫外線、特に波長１９３ｎｍのＡｒＦエキシマレーザ、波長２１３ｎｍのＹＡＧレーザの５倍高調波に対して優れた安定性を有する紫外線レーザ用石英ガラス光学部材を提供することにある。
【０００７】
【課題を解決するための手段】
本発明者は、合成石英ガラス製造時若しくは高温水素処理によって生じる水素起因欠陥が、波長150nmないし300nmの範囲にある、連続光(continuous wave)紫外線の照射により石英ガラスの構造を破壊することなく、前記欠陥のみを選択的に破壊し取り除くことが出来る事を見いだした。
即ち紫外線はパルス光である紫外線レーザと異なり、連続光(continuous wave)なので時間辺りのエネルギー密度は低く、このような還元性欠陥の除去には効果的であるが、石英ガラスの構造を破壊するにはいたらない。但し、このような連続光の紫外線であっても、そのエネルギーが100W/cm2を越えると石英ガラスによっては構造的なダメージを与えられうる事が判明した。
【０００８】
そこで、本発明は、石英ガラス光学部材にArFエキシマレーザあるいはYAGレーザ5倍高調波のように波長の短いレーザの照射に耐えられるように2×1017分子/cm3以上5×1019分子/cm3以下の、好ましくは5×1017分子以上5×1018分子/cm3以下の水素分子を合成石英ガラスの製造時、及び／又は後工程でドーピングする工程と、このとき水素によって生じる還元性の欠陥を波長150nmないし300nmの紫外線の照射によって石英ガラスの構造を破壊することなく除去する事によって、ArFエキシマレーザあるいはYAGレーザ5倍高調波のように波長の短いレーザの照射に対しても耐性の強い石英ガラスを得るものである。
ここで水素濃度の上限値を5×1019分子/cm3以下、好ましくは5×1018分子/cm3以下に限定した理由は前記上限値以上では前記した紫外線の照射のみでは十分に水素起因還元性欠陥を除去し得ないことによる。
【０００９】
そして請求項１記載の発明は、
波長 193nm のＡｒＦエキシマレーザ、波長 213nm のＹＡＧレーザの５倍高調波に対して優れた安定性を有する紫外線レーザ用石英ガラス光学部材の製造方法において、
前記合成石英ガラス中に2×1017分子/cm3以上5×1019分子/cm3以下の水素を含有する工程と、
該水素ガスを含有した石英ガラス部材に波長150nmないし300nmの範囲内の紫外線を、該石英ガラス部材の照射表面における照度として少なくとも1μW/cm2以上、100W/cm2以下のエネルギーで２０時間以上照射する工程とを含み、前記水素を 1 × 10 18 分子 /cm 3 以上含有させた石英ガラスを少なくとも 1 方向に均質化処理した後若しくは均質化処理中において、水素濃度を 2 × 10 17 分子 /cm 3 以上 5 × 10 19 分子 /cm 3 以下の範囲で且つ６００〜１２００℃の温度で水素を含有せしめる高温水素ドーピング工程を具えることを特徴とするものである。
【００１０】
尚、エネルギー照射工程は２０時間以上と、上限を規定していないが、その上限照射時間は還元性欠陥の程度によって定まり、また無用に長時間照射した場合でも石英ガラスの構造を破壊することがないために問題がない。
尚、エネルギー照射工程における照射紫外線は、低圧水銀ランプから放射される184.9nm及び/または253.7nmの波長の発光線、若しくは前記照射紫外線がキセノンランプまたはD2ランプから放射される１５０ｎｍ乃至３００ｎｍの波長の連続スペクトルであるのがよい。
【００１１】
この場合前記水素ガスのドープ前に均質化処理を行うことにより水素ガスが均等にドープされる。
又石英ガラス製造時に水素を1×1018分子/cm3以上含有させる理由は次の理由による。
合成石英ガラスは高純度の四塩化ケイ素原料を用いて酸水素炎加水分解法の直接火炎法（ダイレクト法）やCVDス−ト再溶融法（スート法）にて製造するわけであるが、前記製造の際に酸素ガスを多くして酸素過多雰囲気下で合成を行った場合、当然のように水素ガスは実質的に含有されず、水素は５×1016分子/cm3以下となる。
【００１２】
そしてこのような水素が実質的に含有されていない状態で後工程で水素ドープを行ってもリソグラフィー用のレンズの様な大型の光学部材の場合、水素の拡散速度等の問題で十分に均等で且つ所定濃度の水素分子をドープするのは困難である。
【００１３】
そこで本発明においては、前記合成石英ガラス製造の際に水素ガスを多くして還元雰囲気下で合成を行って水素分子を1×1018分子/cm以上含有させておく。
しかしながら前記のように水素分子を1×1018分子/cm以上含有させても、その後の帯域溶融による均質化処理やアニール処理により水素分子が放散してしまう。
そこで本発明においてはその後の水素ドープ処理若しくはアニール処理と同時に行われる水素ドープ処理により前記放散した水素分子の補充と共に、水素分子の均質拡散を行っている。
即ち本発明は「合成石英ガラス製造時の水素分子含有＋均質化処理後若しくは均質化処理中（アニール処理中）の水素ドープ工程」の２つの組合せにより始めて成立つものである。
尚、前記均質化処理中（アニール処理中）の水素ドープ工程とは水素ガス雰囲気でアニール処理を行うことにより合成石英ガラス製造時の水素分子の拡散を抑制し、水素濃度を2×1017分子/cm3以上5×1019分子/cm3以下の範囲に設定（ドープ処理）することが出来るものである。
【００１４】
又本発明は、均質化処理後若しくは均質化処理中における水素ドープ工程を、６００〜１２００℃の高温度で水素を含有せしめる高温水素ドーピング工程であることを特徴とする。
【００１５】
前記した４００℃以下の温度で水素をドープする技術では拡散速度がきわめて遅いために非常に時間がかかってしまい、特に製品の大型化に対応するためには水素ドープ時間を短縮する必要があり、どうしても高温で水素ドープを行わなくてはならないが、本発明ではこれに対応するものである。
そしてこのように６００℃以上の高温でドープ出来ることは、該ドープ時の熱処理温度を利用して歪除去アニールを並行して行い屈折率の均質性をΔnで2×10-6以下に設定することが可能となり、特に光学部材の特性を向上させる面で極めて有効である。
【００１６】
請求項３記載の発明においては、水素ドープ処理直前における合成石英ガラス水素濃度を規定したもので、合成石英ガラス製造時に水素を含有させた石英ガラスを少なくとも1方向に均質化処理した後、若しくは該均質化処理中において水素濃度が１×1017分子/cm3以上含有する石英ガラスを用いて水素ドープ処理を行い、ドープ後の水素濃度を2×1017分子/cm3以上5×1019分子/cm3以下の範囲に設定することを特徴とするものである。
【００１７】
請求項４及び５記載の発明は、主として合成石英ガラスの製造方法に着目したもので、請求項４記載の発明は主として直接火炎法に関するもので、還元性酸水素火炎中で火炎加水分解し、得られるシリカ微粒子を回転する基体上に堆積しつつ溶融する、いわゆる直接火炎法にて合成された石英ガラスを少なくとも1方向に均質化処理した後若しくは均質化処理中において、水素ドープ処理を行い、ドープ後の水素濃度を2×1017分子/cm3以上5×1019分子/cm3以下の範囲に設定することを特徴とするものである。
【００１８】
請求項５記載の発明は、揮発性硅素化合物を酸素水素火炎にて火炎加水分解して得られるシリカ微粒子を回転する基体上に堆積させ多孔質シリカ母材(スート)を作成し、これを水素含有雰囲気下で透明ガラス化させた石英ガラスを少なくとも1方向に均質化処理した後若しくは均質化処理中において、水素ドープ処理を行い、ドープ後の水素濃度を2×1017分子/cm3以上5×1019分子/cm3以下の範囲に設定することを特徴とするものである。
従って本発明は直接火炎法でもＣＶＤスート法のいずれでも適用できる。
【００１９】
【発明の実施の形態】
以下図面を参照して本発明の実施形態を説明する。
但し、この実施形態に記載されている温度、圧力、材質、時間等、及びこれらに基づく製造方法等は特に特定的な記載がないかぎりは、この発明の範囲をそれに限定する趣旨ではなく、単なる説明例にすぎない。
【００２０】
「実施例１」
先ず本発明に用いる合成石英ガラスの製造方法について説明する。
合成に用いる揮発性珪素化合物には、化学的に合成され、蒸留に依って純化された高純度の発揮性珪素化合物、例えば四塩化けい素（ＳｉＣｌ4 ）等のハロゲン化けい素類、テトラエトキシシラン（Ｓｉ（ＯＣ2Ｈ5）4）、テトラメトキシシラン（Ｓｉ（ＯＣＨ3）4）等のアルコキシシラン類、メチルトリメトキシシシラン（ＳｉＣＨ3（ＯＣＨ3）3 ）等のアルキルアルコキシシラン類を用いる。
この際四塩化珪素（ＳｉＣｌ4 ）等のＣｌ含有の揮発性化合物を用いると生成された合成石英ガラスに塩素が残留し好ましくない。
【００２１】
そして例えば高純度のメチルトリメトキシシシラン（ＳｉＣＨ3（ＯＣＨ3）3）を、水素流量を酸素流量の5倍流して得られる還元性酸水素火炎中で火炎加水分解し、得られるシリカ微粒子を回転する基体上に堆積しつつ溶融する、いわゆる直接火炎法にて外径１００ｍｍ、長さ８００ｍｍの合成石英ガラスインゴットを生成した。
この時インゴットに含有されるOH基濃度は赤外分光光度法による３８００ｃｍ-1の吸収強度から公知の換算式により９００ｐｐｍであることが解った。また、このインゴットに含まれる水素分子濃度をラマン散乱分光光度法にて測定したところ、含有される水素濃度は２×１０18分子／ｃｍ3であった。使用機器は日本分光工業製ＮＲ−１０００、励起波長４８８ｎｍのＡｒレーザーで出力は７００ｍＷ、浜松ホトニクス社製Ｒ９４３−０２ホトマルを使用し、ホトンカウンティングにて測定を行なった。
ここで、本例における水素分子濃度の測定は、文献「Zurnal Pril;adnoi Spektroskopii Vol.46 No.6 pp987 to 991 June 1987」に示される方法で行った。即ち、Sio2に関する波長800cm-1のラマンバンドの強度と合成石英ガラス中に含有される水素分子に関する4135cm-1の強度比により合成石英ガラス中の水素分子濃度を求めるものであり、水素分子濃度Cは次の式(1)により算出される。
C=k(l4135/l800)...(1)
式(1)中、l4135は、4135cm-1のラマンバンドの面積強度である。
l800は、800cm-1のラマンバンドの面積強度である。
kは定数で1.22×1021である。
【００２２】
この合成石英ガラスインゴット３０の両端に同径の石英ガラスの支持棒３２を溶接し、図４に示す均質化処理装置のチャック３１、３１で両端把持した。この左右のチャック３１、３１の回転を同期させ、合成石英ガラスインゴット３０を所定角度往復回転させつつ、その端部を酸素／水素バーナー３４で強加熱し溶融帯域を形成した。溶融帯域３０ａが形成された後、前記左右のチャック３１、３１の回転をそれぞれが相対する方向に回転させることにより、溶融帯域３０ａ内の石英ガラスに周方向に練り込み力を与え混練をした。３５はチャック３１を往復回転させるモ−タである。
次に酸素／水素バーナー３４をゆっくりと合成石英ガラスインゴット３０の他端側に移動させることにより合成石英ガラスインゴット３０全体を均質化した。
均質化後、合成石英ガラスインゴット３０を支持棒３２から切り放し、サンプルを切り出し脈理を観察したところ、インゴットの回転軸と垂直に見た場合の脈理は観察されたものの、インゴットの断面方向には脈理は観察されなかった。
【００２３】
この均質化を終わった合成石英ガラス体を、グラファイト型内で窒素雰囲気下、1800℃以上の高温で直径φ200×100の円盤に成型、取り出し後、大気雰囲気中で1150℃×40時間保持後、-5℃/hの降温速度で除冷し、1方向に脈理がなく使用方向の屈折率の均質性が633nmの波長に対するΔnで1×10-6の高均質な石英ガラス光学部材を得た。ここに得られた石英ガラス光学部材に含有される水素分子濃度は前記と同様なラマン分光法で5×1017分子/cm3であった。
【００２４】
この石英ガラス光学部材から30×30×50mm3の直方体を切り出し6面全面を鏡面に研磨した試料を2個作成し、一方を低圧水銀灯から放射される波長が184.37nmと253.7nmの連続光を照度480μW/cm2で2週間照射した(試料Ａ)。残りはそのまま試料Ｂとした。
試料Ａ及び試料Ｂを出力5W(50mJ/cm2p,100Hz)のArFエキシマレーザで照射し、レーザーエネルギーの透過率を測定したところ図１に示すように、試料Ｂでは照射開始直後から透過率の低下が認められるのに対し、試料Ａではこの透過率の低下がほとんど認められなかった。
【００２５】
「実施例２」
前記と同様にメチルトリメトキシシラン(CH3(OCHH3)3Si)を水素流量を酸素流量の３倍流して得られる還元性酸水素火炎中で火炎加水分解し、得られるシリカ微粒子を回転する基体上に堆積しつつ溶融する、前記と同様な直接火炎法にて合成石英ガラスインゴットを作成した。
この合成石英ガラスインゴットに含まれる水素濃度はラマン分光法で測定したところ、４×１０17分子/cm3であった。
【００２６】
次に該石英ガラスインゴットを旋盤で把持し、前記と同様に溶融帯域法により1方向に均質化処理を行った後、グラファイト型内で窒素雰囲気下、1800℃以上の高温で直径φ200×100の円盤に成型、取り出し後、大気雰囲気中で1150℃×40時間保持後、-5℃/hの降温速度で除冷し、1方向に脈理がなく使用方向の屈折率の均質性が633nmの波長に対するΔnで1×10-6の高均質な石英ガラス光学部材を得た。ここに得られた石英ガラス光学部材に含有される水素分子濃度はラマン分光法で1×1017分子/cm3であった。
【００２７】
この石英ガラス光学部材から30×30×50mm3の直方体を切り出し6面全面を鏡面に研磨した試料を５個作成し、一つを低圧水銀灯から放射される波長が184.37nmと253.7nmの連続光を照度480μW/cm2で2週間照射した(試料Ｃ)。残りはそのまま試料Ｄとした。
更にもう2つの試料を水素雰囲気炉内で水素圧力2kgf/cm2で1000℃、8時間処理して水素ドーピングを行った。この結果2つの試料に於ける含有水素分子濃度はそれぞれ5×1017分子/cm3であった。このうちの1つを実施例1の試料Aと同様の条件で紫外線照射を行い(試料Ｅ)、残り1つはそのまま(試料Ｆ)、実施例1と同じ方法、条件でArFエキシマレーザ照射を行った。
【００２８】
次に前記鏡面研磨後の試料について、水素雰囲気炉内で略５０Ｐａ（パスカル）の高圧水素ガスで封入し、水素圧力５０kgf/cm2で６００℃、７２０時間処理して水素ドーピングを行った。この結果該試料に於ける含有水素分子濃度は5×1019分子/cm3であった。
これを実施例1の試料Ａと同様の条件で紫外線照射を行い(試料Ｊ)、実施例1と同じ方法、条件でArFエキシマレーザ照射を行った。
【００２９】
レーザーエネルギーの透過率を測定したところ図２に示すように、試料Ｄでは照射開始直後から透過率の低下が認められるのに対し、試料Ｃではこの透過率の低下が認められなかった。又図３に示すように、試料Ｆでは照射開始直後から透過率の低下が認められるのに対し、試料Ｅではこの透過率の低下が認められなかった。
一方図には示さないが、資料試料Ｊでは試料D、Fほどではないにしても透過率の低下が認められることが確認された。
【００３０】
「実施例３」
四塩化硅素を酸素水素火炎にて火炎加水分解して得られるシリカ微粒子を回転する基体上に堆積させ多孔質シリカ母材(スート)を作成し、これを水素を含むヘリウム雰囲気下で透明ガラス化し、含有する水素分子濃度が2×1018分子/cm3のシリカガラスインゴットを得た。
このシリカガラスインゴットを実施例1と同じ方法で均質化、成型、アニールを行い含有される水素分子濃度が4×1017分子/cm3の石英ガラス光学部材を得た。
【００３１】
この石英ガラス光学部材から30×30×50mmの直方体を切り出し6面全面を鏡面に研磨した試料を3個作成し、一つを低圧水銀灯から放射される波長が184.37nmと253.7nmの連続光を照度480μW/cm2で2週間照射した(試料Ｇ)。またもう1つはより出力の高い低圧水銀灯を複数個用意しレンズで集光することにより照射エネルギーを100W/cm2にして、100時間照射を行った(試料Ｈ)。残りはそのまま試料Ｉとした。
これらの試料を実施例1と同様の方法、条件でArFエキシマレーザを照射した。
レーザーエネルギーの透過率を測定したところ、図には示さないが、試料Ｈでは照射前から、試料Ｇでは照射開始直後から透過率の低下が認められたのに対し、試料Ｉでは透過率の低下は認められなかった。
【００３２】
【発明の効果】
以上記載の如く本発明によれば、酸水素炎による合成石英ガラス製造時に発生する水素起因欠陥若しくは高温水素処理によって生じる水素起因欠陥を除去し、紫外線、特に波長１９３ｎｍのＡｒＦエキシマレーザ、波長２１３ｎｍのＹＡＧレーザの５倍高調波に対して優れた安定性を有する紫外線レーザ用石英ガラス光学部材を得ることが出来、特に６００℃以上の温度で水素をドープした場合においても、容易に水素起因還元性欠陥を除去することの出来る紫外線レーザ用石英ガラス光学部材を得ることが出来る。
【図面の簡単な説明】
【図１】 前記試料Ａ、及びＢにＡｒＦレーザを出力した場合の内部透過率変化を示すグラフ図である。
【図２】 前記試料Ｃ、ＤにＡｒＦレーザを出力した場合の内部透過率変化を示すグラフ図である。
【図３】 前記試料Ｅ、ＦにＡｒＦレーザを出力した場合の内部透過率変化を示すグラフ図である。
【図４】 本発明の実施例を製造するために用いた脈理除去装置の概略図である。[0001]
BACKGROUND OF THE INVENTION
The present invention, the hydrogen induced defects caused by the hydrogen induced defects or high temperature hydrogen treatment occurs when the synthetic silica glass manufacturing by oxyhydrogen flame is removed, ArF excimer laser of wavelength 193 nm, the fifth harmonic of a YAG laser having a wavelength of 213nm It is to provide a quartz glass optical member for an ultraviolet laser having excellent stability, and particularly suitable for constituting an optical system of an exposure apparatus using these lasers as a light source. For example, a laser beam is used as an exposure light source. The present invention relates to a quartz glass optical member for ultraviolet laser that can constitute the used exposure apparatus.
[0002]
[Prior art]
In recent years, along with the high integration of LSIs, the lithography technology for drawing integrated circuit patterns on wafers also requires drawing technology in sub-micron units. Therefore, in order to perform finer line width drawing, exposure is performed. The shortening of the wavelength of the light source of the system has been promoted.
For example, as a light source for a lithography stepper, a conventional KrF excimer laser having a wavelength of 248 nm from G-line (436 nm) and i-line (365 nm) has been used. (193 nm) and YAG laser fifth harmonic (213 nm) are being studied for exposure with a laser light source.
[0003]
On the other hand, in the short wavelength ultraviolet region shorter than the i-line (365 nm), sufficient light transmission cannot be obtained with the conventional multicomponent optical glass. Therefore, quartz glass also reduces ultraviolet absorption as much as possible. In addition, high-purity synthetic quartz glass with a low impurity content is used.
However, although the method of improving the transmittance of the ultraviolet laser by improving the purity of the synthetic quartz glass is effective to some extent, the excimer laser beam is a pulsed beam having a lifetime of about 20 nsec. Since the energy per hour is very high compared to the ultraviolet rays radiated from the glass, the load applied to the glass is extremely large, so that it is easily damaged by the long-term irradiation of the laser light.
In order to eliminate such drawbacks, the present applicant has proposed a technique in which hydrogen gas is doped into the quartz glass body, specifically, hydrogen gas is contained at 10 17 cm 3 or more. (USP 5,086,352, etc.)
[0004]
[Problems to be solved by the invention]
As a result of the further high integration of recent LSIs, the study of exposure using an ArF excimer laser (193 nm) or a YAG laser fifth harmonic (213 nm) with a shorter wavelength is proceeding from a KrF excimer laser with a wavelength of 248 nm.
Since these laser light sources have a shorter wavelength than that of the KrF excimer laser, the energy of the light is larger and the quartz glass is more damaged than before. For this reason, high energy ArF excimer lasers and YAG fifth harmonics require a higher concentration of hydrogen to provide sufficient laser resistance to the laser.
However, as disclosed in JP-A-6-166528, hydrogen doped into quartz glass during the growth of synthetic quartz glass, or hydrogen doped into synthetic quartz glass at a temperature of 600 ° C. or higher as a post process, Hydrogen is produced during the growth of quartz glass, which is the most efficient to dope hydrogen, in order to cause reductive defects, which cause paramagnetic defects called E * centers with absorption at a wavelength of 215 nm immediately after the start of excimer laser irradiation. The method of doping is not used.
The E * center is not a problem because the wavelength is long in the KrF laser, but the paramagnetic defect caused by the E * center is a problem in the fifth harmonic of the ArF excimer laser having a wavelength of 193 nm or the YAG laser having a wavelength of 213 nm. It becomes.
[0005]
For this reason, the present applicant first performs an oxidation heat treatment in a temperature range of 1500 ° C. or lower to remove hydrogen-induced reducing defects in the starting base material, and then at a temperature of 600 ° C. or lower, preferably 400 ° C. or lower. A technology for doping hydrogen is proposed. (Japanese Patent Laid-Open No. 6-166528)
However, it is possible to dope the required high concentration of hydrogen at a low temperature of 600 ° C. or less, preferably 400 ° C. or less, but it is very time consuming and inefficient.
[0006]
In view of the shortcomings of the prior art, the present invention is a quartz glass optical for ultraviolet laser that can easily remove hydrogen-induced reducing defects even when hydrogen is doped at a temperature of 400 ° C. or higher, preferably 600 ° C. or higher. It aims at providing the manufacturing method of a member.
Another object of the present invention is to remove hydrogen-induced defects generated during the production of synthetic quartz glass by an oxyhydrogen flame or hydrogen-induced defects caused by high-temperature hydrogen treatment, and ultraviolet rays, particularly an ArF excimer laser having a wavelength of 193 nm, a YAG laser having a wavelength of 213 nm. An object of the present invention is to provide a quartz glass optical member for an ultraviolet laser having excellent stability with respect to the fifth harmonic.
[0007]
[Means for Solving the Problems]
The present inventor has a defect caused by hydrogen during synthetic quartz glass production or high-temperature hydrogen treatment in the wavelength range of 150 nm to 300 nm, without destroying the structure of the quartz glass by continuous wave ultraviolet irradiation, It has been found that only the defects can be selectively destroyed and removed.
In other words, unlike ultraviolet laser, which is pulsed light, ultraviolet light is continuous wave, so its energy density per hour is low, and it is effective in removing such reducing defects, but it destroys the structure of quartz glass. I don't want to. However, it has been found that even with such continuous UV rays, structural damage can be caused by quartz glass if the energy exceeds 100 W / cm 2 .
[0008]
Therefore, the present invention provides a quartz glass optical member having a wavelength of 2 × 10 17 molecules / cm 3 or more and 5 × 10 19 molecules / cm3 so that it can withstand irradiation with a laser having a short wavelength such as an ArF excimer laser or a YAG laser 5th harmonic. A step of doping hydrogen molecules of cm 3 or less, preferably 5 × 10 17 molecules or more and 5 × 10 18 molecules / cm 3 or less in the production of synthetic quartz glass and / or in a later step, and reduction caused by hydrogen at this time By removing ultraviolet defects with a wavelength of 150nm to 300nm without destroying the structure of quartz glass, it is possible to irradiate lasers with short wavelengths such as ArF excimer lasers or YAG lasers 5th harmonics. A quartz glass with high resistance is obtained.
Here, the upper limit of the hydrogen concentration is limited to 5 × 10 19 molecules / cm 3 or less, preferably 5 × 10 18 molecules / cm 3 or less. This is because reducing defects cannot be removed.
[0009]
And invention of
In a method for producing a quartz glass optical member for an ultraviolet laser having excellent stability with respect to the fifth harmonic of an ArF excimer laser having a wavelength of 193 nm and a YAG laser having a wavelength of 213 nm,
A step of containing 5 × 10 19 molecules / cm 3 or less of the hydrogen 2 × 10 17 molecules / cm 3 or more to the synthetic quartz glass,
The quartz glass member containing hydrogen gas is irradiated with ultraviolet rays having a wavelength in the range of 150 nm to 300 nm with an energy of at least 1 μW / cm 2 or more and 100 W / cm 2 or less as an illuminance on the irradiation surface of the quartz glass member for 20 hours or more. to include a step, in the
[0010]
The energy irradiation process does not define an upper limit of 20 hours or more, but the upper limit irradiation time is determined by the degree of reducing defects, and the structure of quartz glass can be destroyed even when irradiated unnecessarily for a long time. There is no problem for not.
The irradiation ultraviolet ray in the energy irradiation step is an emission line having a wavelength of 184.9 nm and / or 253.7 nm emitted from a low-pressure mercury lamp, or a wavelength of 150 to 300 nm emitted from the xenon lamp or D2 lamp. It should be a continuous spectrum.
[0011]
In this case, the hydrogen gas is uniformly doped by performing a homogenization treatment before the doping of the hydrogen gas.
The reason why hydrogen is contained at 1 × 10 18 molecules / cm 3 or more in the production of quartz glass is as follows.
Synthetic quartz glass is manufactured by high-purity silicon tetrachloride raw material by direct flame method of oxyhydrogen flame hydrolysis (direct method) and CVD soot remelting method (soot method). When the synthesis is carried out in an oxygen-rich atmosphere by increasing the oxygen gas during production, the hydrogen gas is not substantially contained as a matter of course, and the hydrogen is 5 × 10 16 molecules / cm 3 or less.
[0012]
And even if hydrogen doping is carried out in a subsequent process in a state where such hydrogen is not substantially contained, in the case of a large optical member such as a lens for lithography, it is sufficiently uniform due to problems such as hydrogen diffusion rate. Moreover, it is difficult to dope a predetermined concentration of hydrogen molecules.
[0013]
Therefore, in the present invention , when the synthetic quartz glass is produced, hydrogen gas is increased and synthesis is performed in a reducing atmosphere so that hydrogen molecules are contained in an amount of 1 × 10 18 molecules / cm or more.
However, even if hydrogen molecules are contained in an amount of 1 × 10 18 molecules / cm or more as described above, the hydrogen molecules are dissipated by the subsequent homogenization or annealing treatment by zone melting.
Therefore, in the present invention, the hydrogen molecules are homogeneously diffused together with the replenishment of the diffused hydrogen molecules by the subsequent hydrogen doping process or the hydrogen doping process performed simultaneously with the annealing process.
That is, the present invention is established only by two combinations of “hydrogen molecule content at the time of manufacturing synthetic quartz glass + hydrogen doping step after homogenization treatment or during homogenization treatment (during annealing treatment)”.
The hydrogen doping process during the homogenization process (during the annealing process) suppresses the diffusion of hydrogen molecules during the production of synthetic quartz glass by performing an annealing process in a hydrogen gas atmosphere, so that the hydrogen concentration is 2 × 10 17 molecules. It can be set (dope treatment) within the range of / cm 3 or more and 5 × 10 19 molecules / cm 3 or less.
[0014]
The present invention is characterized in that the hydrogen doping process in the homogenization or after homogenization during processing, is a high temperature hydrogen doping process allowed to contain hydrogen at a high temperature of 6 00-1,200 ° C..
[0015]
The above-described technology for doping hydrogen at a temperature of 400 ° C. or lower takes a very long time because the diffusion rate is extremely slow, and it is particularly necessary to shorten the hydrogen doping time in order to cope with an increase in the size of the product. Inevitably, hydrogen doping must be performed at a high temperature, but the present invention corresponds to this.
In addition, the fact that doping can be performed at a high temperature of 600 ° C. or higher in this way is that strain annealing is performed in parallel using the heat treatment temperature at the time of doping, and the refractive index homogeneity is set to 2 × 10 −6 or less in Δn. This is particularly effective in improving the characteristics of the optical member.
[0016]
In the invention described in
[0017]
The inventions according to claims 4 and 5 mainly focus on a method for producing synthetic quartz glass, and the invention according to claim 4 mainly relates to a direct flame method, in which flame hydrolysis is performed in a reducing oxyhydrogen flame, The silica fine particles obtained are melted while being deposited on a rotating substrate, and the silica glass synthesized by a so-called direct flame method is subjected to a hydrogen doping treatment after homogenizing in at least one direction or during the homogenizing treatment. The hydrogen concentration after doping is set in the range of 2 × 10 17 molecules / cm 3 or more and 5 × 10 19 molecules / cm 3 or less.
[0018]
According to the fifth aspect of the present invention, a porous silica base material (soot) is prepared by depositing silica fine particles obtained by hydrolyzing a volatile silicon compound with an oxygen-hydrogen flame on a rotating substrate. After quartz glass made transparent vitrified in a contained atmosphere is homogenized in at least one direction or during homogenization, hydrogen doping is performed, and the hydrogen concentration after doping is 2 × 10 17 molecules / cm 3 or more 5 × 10 19 molecules / cm 3 or less is set.
Therefore, the present invention can be applied to either a direct flame method or a CVD soot method.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
However, the temperature, pressure, material, time, and the like described in this embodiment, and the manufacturing method based on these, are not intended to limit the scope of the present invention unless otherwise specified. It is just an example.
[0020]
"Example 1"
First, a method for producing a synthetic quartz glass used in the present invention will be described.
The volatile silicon compounds used for the synthesis include high-purity silicon compounds chemically synthesized and purified by distillation, for example, silicon halides such as silicon tetrachloride (SiCl 4 ), tetraethoxy Alkoxyalkoxysilanes such as alkoxysilanes such as silane (Si (OC 2 H 5 ) 4 ) and tetramethoxysilane (Si (OCH 3 ) 4 ) and methyltrimethoxysilane (SiCH 3 (OCH 3 ) 3 ) Use.
At this time, if a volatile compound containing Cl such as silicon tetrachloride (SiCl 4 ) is used, chlorine remains in the produced synthetic quartz glass, which is not preferable.
[0021]
For example, high-purity methyltrimethoxysilane (SiCH 3 (OCH 3 ) 3 ) is subjected to flame hydrolysis in a reducing oxyhydrogen flame obtained by flowing a hydrogen flow rate five times the oxygen flow rate. A synthetic quartz glass ingot having an outer diameter of 100 mm and a length of 800 mm was produced by a so-called direct flame method that melts while being deposited on a rotating substrate.
At this time, the OH group concentration contained in the ingot was found to be 900 ppm by a known conversion formula from the absorption intensity of 3800 cm −1 by infrared spectrophotometry. Further, when the concentration of hydrogen molecules contained in the ingot was measured by Raman scattering spectrophotometry, the concentration of contained hydrogen was 2 × 10 18 molecules / cm 3 . The equipment used was NR-1000 manufactured by JASCO Corporation, an Ar laser with an excitation wavelength of 488 nm, an output of 700 mW, and R943-02 Photomal manufactured by Hamamatsu Photonics Co., Ltd., and measurement was performed by photon counting.
Here, the measurement of the hydrogen molecule concentration in this example was performed by the method described in the document “Zurnal Pril; adnoi Spektroskopii Vol.46 No.6 pp987 to 991 June 1987”. That is, the hydrogen molecule concentration in the synthetic quartz glass is obtained from the intensity ratio of the Raman band at a wavelength of 800 cm -1 for Sio 2 and the intensity ratio of 4135 cm -1 for the hydrogen molecules contained in the synthetic quartz glass. C is calculated by the following equation (1).
C = k (l 4135 / l 800 ) ... (1)
In formula (1), l 4135 is the area intensity of the Raman band of 4135 cm −1 .
l 800 is the area intensity of the Raman band of 800 cm −1 .
k is a constant and is 1.22 × 10 21 .
[0022]
A quartz
Next, the entire synthetic
After homogenization, the synthetic
[0023]
This homogenized synthetic quartz glass body was molded into a disk with a diameter of φ200 × 100 at a high temperature of 1800 ° C. or higher in a graphite mold under a nitrogen atmosphere, and after being taken out, held in the atmosphere for 1150 ° C. × 40 hours, Cooling is performed at a temperature drop rate of -5 ° C / h to obtain a highly homogeneous quartz glass optical member with no striation in one direction and a refractive index homogeneity in the direction of use of 1 × 10 -6 with Δn for a wavelength of 633 nm. It was. The concentration of hydrogen molecules contained in the quartz glass optical member obtained here was 5 × 10 17 molecules / cm 3 by Raman spectroscopy as described above.
[0024]
Cut out a 30 x 30 x 50 mm 3 rectangular parallelepiped from this quartz glass optical member and make two samples with the entire 6-surface polished to a mirror surface. One of the samples emits continuous light with a wavelength of 184.37 nm and 253.7 nm emitted from a low-pressure mercury lamp. Irradiation was performed for 2 weeks at an illuminance of 480 μW / cm 2 (Sample A). The rest was used as sample B as it was.
Sample A and sample B were irradiated with an ArF excimer laser with an output of 5 W (50 mJ / cm 2 p, 100 Hz), and the transmittance of the laser energy was measured. As shown in FIG. In contrast, the transmittance of Sample A was hardly decreased.
[0025]
"Example 2"
In the same manner as above, methyltrimethoxysilane (CH 3 (OCHH 3 ) 3 Si) is flame hydrolyzed in a reducing oxyhydrogen flame obtained by flowing the hydrogen flow rate three times the oxygen flow rate, and the resulting silica fine particles are rotated. A synthetic quartz glass ingot was prepared by the direct flame method similar to the above, which melts while being deposited on the substrate.
The hydrogen concentration contained in this synthetic quartz glass ingot was 4 × 10 17 molecules / cm 3 as measured by Raman spectroscopy.
[0026]
Next, the quartz glass ingot is gripped with a lathe and subjected to a homogenization treatment in one direction by the melting zone method in the same manner as described above, and then a diameter of φ200 × 100 at a high temperature of 1800 ° C. or higher in a nitrogen atmosphere in a graphite mold. Molded into a disk, removed, held in air at 1150 ° C for 40 hours, then cooled at a temperature drop rate of -5 ° C / h, with no striation in one direction and a refractive index homogeneity in the direction of use of 633 nm A highly uniform quartz glass optical member having a Δn of 1 × 10 −6 with respect to the wavelength was obtained. The concentration of hydrogen molecules contained in the quartz glass optical member obtained here was 1 × 10 17 molecules / cm 3 by Raman spectroscopy.
[0027]
Cut out a 30 × 30 × 50mm 3 rectangular parallelepiped from this quartz glass optical member and make five samples with the entire surface polished to a mirror surface, one of which is a continuous light with wavelengths 184.37nm and 253.7nm emitted from a low-pressure mercury lamp. Was irradiated at an illuminance of 480 μW / cm 2 for 2 weeks (Sample C). The rest was used as sample D as it was.
Two more samples were subjected to hydrogen doping in a hydrogen atmosphere furnace at a hydrogen pressure of 2 kgf / cm 2 at 1000 ° C. for 8 hours. As a result, the hydrogen molecule concentrations in the two samples were 5 × 10 17 molecules / cm 3 , respectively. One of them is irradiated with ultraviolet rays under the same conditions as Sample A in Example 1 (Sample E), and the other one is left as it is (Sample F). ArF excimer laser irradiation is performed under the same method and conditions as in Example 1. went.
[0028]
Next, the sample after the mirror polishing was filled with high-pressure hydrogen gas of about 50 Pa (pascal) in a hydrogen atmosphere furnace, and was subjected to hydrogen doping by treatment at 600 ° C. for 720 hours at a hydrogen pressure of 50 kgf / cm 2 . As a result, the hydrogen molecule concentration in the sample was 5 × 10 19 molecules / cm 3 .
This was irradiated with ultraviolet rays under the same conditions as Sample A of Example 1 (Sample J), and irradiated with ArF excimer laser under the same method and conditions as in Example 1.
[0029]
When the transmittance of the laser energy was measured, as shown in FIG. 2, in Sample D, a decrease in transmittance was observed immediately after the start of irradiation, whereas in Sample C, this decrease in transmittance was not observed. Further, as shown in FIG. 3, in Sample F, a decrease in transmittance was observed immediately after the start of irradiation, whereas in Sample E, this decrease in transmittance was not recognized.
On the other hand, although not shown in the figure, it was confirmed that the transmittance of the material sample J was found to be lower than that of the samples D and F.
[0030]
"Example 3"
A porous silica base material (soot) is made by depositing silica fine particles obtained by hydrolyzing silicon tetrachloride in an oxygen-hydrogen flame on a rotating substrate, and this is transparently vitrified in a helium atmosphere containing hydrogen. A silica glass ingot having a hydrogen molecule concentration of 2 × 10 18 molecules / cm 3 was obtained.
The silica glass ingot was homogenized, molded, and annealed in the same manner as in Example 1 to obtain a quartz glass optical member having a hydrogen molecule concentration of 4 × 10 17 molecules / cm 3 .
[0031]
Cut out a 30 x 30 x 50 mm rectangular parallelepiped from this quartz glass optical member, and create three samples with the entire 6 surfaces polished to a mirror surface, one of which emits continuous light with wavelengths of 184.37 nm and 253.7 nm emitted from a low-pressure mercury lamp. Irradiation was performed for 2 weeks at an illuminance of 480 μW / cm 2 (Sample G). The other was prepared with a plurality of low-pressure mercury lamps with higher output and condensed with a lens to make the irradiation energy 100 W / cm 2 and irradiated for 100 hours (sample H). The rest was used as Sample I as it was.
These samples were irradiated with an ArF excimer laser under the same method and conditions as in Example 1.
When the transmittance of the laser energy was measured, although not shown in the figure, a decrease in transmittance was observed in Sample H from before irradiation and in Sample G immediately after the start of irradiation, whereas in Sample I, a decrease in transmittance was observed. Was not recognized.
[0032]
【The invention's effect】
As described above, according to the present invention, hydrogen-induced defects generated during the production of synthetic quartz glass by an oxyhydrogen flame or hydrogen-induced defects generated by high-temperature hydrogen treatment are removed, and ultraviolet rays, particularly an ArF excimer laser with a wavelength of 193 nm, a wavelength of 213 nm, are removed. It can be obtained an ultraviolet laser for quartz glass optical member having excellent stability against fifth harmonic of a YAG laser, even when doped with hydrogen in Japanese to 6 00 ° C. or higher, readily hydrogen due It is possible to obtain a quartz glass optical member for ultraviolet laser capable of removing reducing defects.
[Brief description of the drawings]
FIG. 1 is a graph showing changes in internal transmittance when an ArF laser is output to the samples A and B. FIG.
FIG. 2 is a graph showing changes in internal transmittance when an ArF laser is output to the samples C and D;
FIG. 3 is a graph showing a change in internal transmittance when an ArF laser is output to the samples E and F;
FIG. 4 is a schematic view of a striae removing device used for manufacturing an embodiment of the present invention.
Claims (6)
前記合成石英ガラス中に2×1017分子/cm3以上5×1019分子/cm3以下の水素を含有する工程と、
該水素ガスを含有した石英ガラス部材に波長150nmないし300nmの範囲内の紫外線を、該石英ガラス部材の照射表面における照度として少なくとも1μW/cm2以上、100W/cm2以下のエネルギーで２０時間以上照射する工程とを含み、前記水素を 1 × 10 18 分子 /cm 3 以上含有させた石英ガラスを少なくとも 1 方向に均質化処理した後若しくは均質化処理中において、水素濃度を 2 × 10 17 分子 /cm 3 以上 5 × 10 19 分子 /cm 3 以下の範囲で且つ６００〜１２００℃の温度で水素を含有せしめる高温水素ドーピング工程を具えることを特徴とする紫外線レーザ用石英ガラス光学部材の製造方法。 In a method for producing a quartz glass optical member for an ultraviolet laser having excellent stability with respect to the fifth harmonic of an ArF excimer laser having a wavelength of 193 nm and a YAG laser having a wavelength of 213 nm,
A step of containing 5 × 10 19 molecules / cm 3 or less of the hydrogen 2 × 10 17 molecules / cm 3 or more to the synthetic quartz glass,
The quartz glass member containing hydrogen gas is irradiated with ultraviolet rays having a wavelength in the range of 150 nm to 300 nm with an energy of at least 1 μW / cm 2 or more and 100 W / cm 2 or less as an illuminance on the irradiation surface of the quartz glass member for 20 hours or more. to include a step, in the hydrogen 1 × 10 18 molecules / cm 3 or more after the quartz glass containing the homogenized in at least one direction or homogenization processing, the hydrogen concentration 2 × 10 17 molecules / cm 3 to 5 × 10 19 molecules / cm 3 the following method for producing range and 600 to 1200 ° C. ultraviolet laser for quartz glass optical member characterized by comprising a high temperature hydrogen doping process allowed to contain hydrogen at a temperature of.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30643895A JP3674793B2 (en) | 1995-10-31 | 1995-10-31 | Method for producing quartz glass optical member for ultraviolet laser |
| PCT/EP1996/004746 WO1997016382A1 (en) | 1995-10-31 | 1996-10-31 | Process for producing quartz glass optical body for ultraviolet-emitting lasers and quartz glass body produced according to the process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30643895A JP3674793B2 (en) | 1995-10-31 | 1995-10-31 | Method for producing quartz glass optical member for ultraviolet laser |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09124337A JPH09124337A (en) | 1997-05-13 |
| JP3674793B2 true JP3674793B2 (en) | 2005-07-20 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30643895A Expired - Lifetime JP3674793B2 (en) | 1995-10-31 | 1995-10-31 | Method for producing quartz glass optical member for ultraviolet laser |
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| JP (1) | JP3674793B2 (en) |
| WO (1) | WO1997016382A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6333283B1 (en) | 1997-05-16 | 2001-12-25 | Sumitomo Electric Industries, Ltd. | Silica glass article and manufacturing process therefor |
| JP2980094B2 (en) * | 1997-05-16 | 1999-11-22 | 住友電気工業株式会社 | Quartz glass article and method for producing the same |
| DE69816758T2 (en) * | 1997-05-20 | 2004-06-03 | Heraeus Quarzglas Gmbh & Co. Kg | SYNTHETIC QUARTZ GLASS FOR USE IN UV RADIATION AND METHOD FOR THE PRODUCTION THEREOF |
| KR100554091B1 (en) | 1997-12-08 | 2006-05-16 | 가부시키가이샤 니콘 | Manufacture method of quartz glass with improved excimer laser resistance and quartz glass member |
| JP2000143258A (en) * | 1998-09-10 | 2000-05-23 | Shinetsu Quartz Prod Co Ltd | PRODUCTION OF SYNTHETIC QUARTZ GLASS FOR ArF EXCIMER LASER LITHOGRAPHY |
| JP4601022B2 (en) * | 1999-03-04 | 2010-12-22 | 信越石英株式会社 | Synthetic quartz glass member for ArF excimer laser lithography |
| EP1088795A4 (en) * | 1999-03-25 | 2004-03-31 | Asahi Glass Co Ltd | Synthetic quartz glass for optical member, process for producing the same, and method of using the same |
| JP4051805B2 (en) * | 1999-03-25 | 2008-02-27 | 旭硝子株式会社 | Exposure apparatus and photomask |
| US6578382B2 (en) | 2000-03-29 | 2003-06-17 | Heraeus Quarzglas Gmbh & Co. Kg | Synthetic quartz glass for optical use, heat treatment method and heat treatment apparatus for the same |
| JP4462720B2 (en) * | 2000-06-06 | 2010-05-12 | 信越石英株式会社 | Heat treatment method for optical synthetic quartz glass |
| JP4107905B2 (en) * | 2002-07-31 | 2008-06-25 | 信越石英株式会社 | Synthetic silica glass optical material for YAG laser harmonics |
| JP2006219309A (en) * | 2005-02-08 | 2006-08-24 | Asahi Glass Co Ltd | Method and apparatus for producing porous quartz glass preform |
| US20070049482A1 (en) | 2005-08-11 | 2007-03-01 | Shin-Etsu Chemical Co., Ltd. | Synthetic quartz glass substrate for excimer lasers and making method |
| JP5208677B2 (en) * | 2008-11-04 | 2013-06-12 | 信越石英株式会社 | Method for producing synthetic quartz glass member for ArF excimer laser lithography |
| WO2014080840A1 (en) * | 2012-11-20 | 2014-05-30 | Hoya株式会社 | Mask blank, transfer mask, method for producing mask blank, method for producing transfer mask, and method for manufacturing semiconductor device |
| US9603775B2 (en) | 2013-04-24 | 2017-03-28 | Corning Incorporated | Delamination resistant pharmaceutical glass containers containing active pharmaceutical ingredients |
| JP7060386B2 (en) | 2017-04-26 | 2022-04-26 | 東ソ－・エスジ－エム株式会社 | Ultraviolet resistant quartz glass and its manufacturing method |
| CN110612274B (en) | 2017-04-26 | 2022-04-01 | 东曹石英素材股份有限公司 | Ultraviolet-resistant quartz glass and manufacturing method thereof |
| CN111018329B (en) * | 2019-12-23 | 2022-09-23 | 中国工程物理研究院核物理与化学研究所 | Preparation and curing method of optical component/optical material color center |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62143844A (en) * | 1985-12-13 | 1987-06-27 | Furukawa Electric Co Ltd:The | Treatment of light-transmitting material |
| DE69015453T3 (en) * | 1989-06-09 | 2001-10-11 | Heraeus Quarzglas Gmbh & Co. Kg | Optical parts and blanks made of synthetic silicon dioxide glass and process for their production. |
| US5410428A (en) * | 1990-10-30 | 1995-04-25 | Shin-Etsu Quartz Products Co. Ltd. | Optical member made of high-purity and transparent synthetic silica glass and method for production thereof or blank thereof |
| JP2821074B2 (en) * | 1992-11-30 | 1998-11-05 | 信越石英株式会社 | Manufacturing method of optical member for UV resistant laser |
-
1995
- 1995-10-31 JP JP30643895A patent/JP3674793B2/en not_active Expired - Lifetime
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| JPH09124337A (en) | 1997-05-13 |
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