JP2003344601A - Device and method for cleaning optical element and method for manufacturing it - Google Patents
Device and method for cleaning optical element and method for manufacturing itInfo
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- JP2003344601A JP2003344601A JP2002154699A JP2002154699A JP2003344601A JP 2003344601 A JP2003344601 A JP 2003344601A JP 2002154699 A JP2002154699 A JP 2002154699A JP 2002154699 A JP2002154699 A JP 2002154699A JP 2003344601 A JP2003344601 A JP 2003344601A
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- Japan
- Prior art keywords
- cleaning
- optical element
- vacuum ultraviolet
- ultraviolet light
- cleaning chamber
- Prior art date
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- Physical Vapour Deposition (AREA)
- Surface Treatment Of Optical Elements (AREA)
- Cleaning In General (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、光学素子の洗浄装
置及び光学素子の洗浄方法、および光学素子の製造方法
に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element cleaning apparatus, an optical element cleaning method, and an optical element manufacturing method.
【０００２】[0002]
【従来の技術】近年、半導体素子のリソグラフィー工程
に用いる縮小投影露光装置（ステッパー）の露光波長
は、半導体素子の集積度向上を目的とした高解像力化の
要求が高まり、短波長化が求められている。そこで最近
では、エキシマレーザーを光源としたステッパーの実用
化が始まっている。しかしながら、有機物をはじめとす
る汚れの吸収・散乱や干渉現象などは、光が短波長であ
るほど顕著になるため、光源が短波長になるに連れ、例
えばレンズ及びミラーなどの光学素子に付着残留してい
る有機物などの汚れが、光源からの光を吸収・散乱した
り、光学素子の分光特性を変化させたりして、透過率等
の光学特性を低下させている。吸収や散乱による透過率
の劣化はステッパーの生産性を低下させるばかりでな
く、吸収による発熱や散乱・反射率の増加によるフレア
ーの発生など、ステッパーの性能にも多大な影響を及ぼ
し、高解像力化を行う上でも問題となっている。また、
通常レンズなどの光学素子表面には反射防止膜などのコ
ーティングを施すが、この際にレンズ表面が汚れていて
は、コーティングを施した光学素子の透過率劣化や、吸
収増大の原因となり、結果として光学素子の性能が劣化
していた。2. Description of the Related Art In recent years, with respect to the exposure wavelength of a reduction projection exposure apparatus (stepper) used in a lithography process of semiconductor elements, there is an increasing demand for higher resolution for the purpose of improving the integration degree of semiconductor elements, and a shorter wavelength is required. ing. Therefore, recently, practical use of a stepper using an excimer laser as a light source has started. However, the absorption / scattering and interference phenomena of stains such as organic matter become more prominent as the wavelength of light becomes shorter.Therefore, as the wavelength of the light source becomes shorter, they adhere to optical elements such as lenses and mirrors. Dirt such as organic matter that is absorbed absorbs and scatters light from the light source or changes the spectral characteristics of the optical element, thereby reducing optical characteristics such as transmittance. The deterioration of the transmittance due to absorption and scattering not only lowers the productivity of the stepper, but also has a great influence on the performance of the stepper, such as heat generation due to absorption and flare due to increased scattering and reflectance, resulting in high resolution. Is also a problem in doing. Also,
Normally, the surface of optical elements such as lenses is coated with an antireflection film, etc., but if the lens surface is dirty at this time, it may cause deterioration of the transmittance of the coated optical elements or increase absorption, resulting in The performance of the optical element was degraded.
【０００３】このような事情から、光学素子やコーティ
ング前の基板表面に付着残留している有機物などの汚れ
を効率的に取り除く光学素子の洗浄が要求されている。
しかも、近年真空紫外域で使用されることの多い蛍石基
板などの結晶材料はプラズマや不適切な有機・無機溶剤
及び水溶液を用いるとダメージが生じやすく、基板材料
にダメージを与えない洗浄方法が求められている。Under these circumstances, there is a demand for cleaning optical elements and optical elements that efficiently remove stains such as organic substances remaining on the surface of a substrate before coating.
Moreover, crystal materials such as fluorite substrates, which are often used in the vacuum ultraviolet region in recent years, are easily damaged when plasma or an inappropriate organic / inorganic solvent or aqueous solution is used, and there is a cleaning method that does not damage the substrate materials. It has been demanded.
【０００４】これらのような要求を満たすドライ洗浄法
の１つとして、光化学反応を利用する紫外線／オゾン洗
浄法がある。従来の紫外線／オゾン洗浄法では紫外線光
源として水銀ランプやエキシマランプなどのランプを用
い、洗浄雰囲気を通常の大気や、汚染の影響を除去する
ため酸素ガスを導入し、真空紫外光によってオゾン及び
酸素ラジカルを生成し、この活性種によって洗浄を行っ
ていた。また、特開平８−８５８６１号公報では真空紫
外光を減圧環境下の低酸素分圧条件で被処理物に照射
し、洗浄を行う方法は開示されている。As one of the dry cleaning methods satisfying these requirements, there is an ultraviolet / ozone cleaning method utilizing a photochemical reaction. In the conventional ultraviolet / ozone cleaning method, a lamp such as a mercury lamp or an excimer lamp is used as an ultraviolet light source, a cleaning atmosphere is normal air, or oxygen gas is introduced to remove the influence of pollution, and ozone and oxygen are removed by vacuum ultraviolet light. Radicals were generated and cleaning was performed with this active species. Further, Japanese Unexamined Patent Publication No. 8-85861 discloses a method of irradiating a treatment object with vacuum ultraviolet light under a low oxygen partial pressure condition under a reduced pressure environment to perform cleaning.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、従来の
水銀ランプやエキシマランプなどのランプを用いた紫外
線／オゾン洗浄法では真空紫外光が雰囲気中の酸素に吸
収されるため、真空紫外光強度はすぐに減衰してしま
う。このため、洗浄効果はランプ近傍でしか得られず、
Ｓｉウエハ等の洗浄には適しているが、レンズなど立体
的な光学素子の洗浄には不適である。また、減圧環境下
で照射する場合は、真空紫外光の減衰を防止できるが、
減圧にする際にポンプや隔壁、照射チャンバー内にある
各種の素子等から放出される不純物が付着し、再汚染し
てしまい、真空紫外域の吸収原因となる汚染を効率的に
除去することができない。However, since the vacuum ultraviolet light is absorbed by oxygen in the atmosphere in the conventional ultraviolet / ozone cleaning method using a lamp such as a mercury lamp or an excimer lamp, the intensity of the vacuum ultraviolet light is short. Decays to. Therefore, the cleaning effect can be obtained only near the lamp,
Although it is suitable for cleaning Si wafers and the like, it is not suitable for cleaning three-dimensional optical elements such as lenses. Also, when irradiating in a reduced pressure environment, it is possible to prevent the attenuation of vacuum ultraviolet light,
Impurities emitted from the pump, partition walls, various elements in the irradiation chamber, etc. adhere to the surface when decompressing and recontaminate, and the contamination that causes absorption in the vacuum ultraviolet region can be efficiently removed. Can not.
【０００６】そこで、本発明は、上記課題を解決し、被
洗浄物である光学素子に付着残留している有機物などの
汚れを安価で効率的に取り除くことができ、またこれら
の汚れを光学素子にダメージを与えることなく容易に取
り除くことが可能となる光学素子の洗浄装置及び光学素
子の洗浄方法、および光学素子の製造方法を提供するこ
とを例示的目的とするものである。Therefore, the present invention solves the above-mentioned problems and can efficiently remove stains such as organic substances remaining on the optical element which is the object to be cleaned at a low cost, and these stains can be removed by the optical element. It is an exemplary object to provide an optical element cleaning device, an optical element cleaning method, and an optical element manufacturing method that can be easily removed without damaging the optical element.
【０００７】[0007]
【課題を解決するための手段】本発明は、つぎの（１）
〜（１３）のように構成した光学素子の洗浄装置及び光
学素子の洗浄方法、および光学素子の製造方法を提供す
るものである。
（１）真空紫外光を照射して、洗浄室内に収容された被
洗浄物である光学素子表面の有機物等の汚染物を除去す
る光学素子の洗浄装置において、前記洗浄室内に酸素ガ
ス及び真空紫外光を吸収しないガスを供給し、前記洗浄
室内に供給された酸素ガスの濃度を前記真空紫外光を吸
収しないガスの供給によって調整する供給・調整装置を
有し、前記酸素ガスを所定の酸素濃度に調整した状態で
前記真空紫外光を前記被洗浄物に照射可能としたことを
特徴とする光学素子の洗浄装置。
（２）前記装置は、酸素濃度検出器によって検出された
洗浄室内の酸素濃度に基づいて、前記洗浄室内を所望の
酸素濃度に調整する手段を有することを特徴とする上記
（１）に記載の光学素子の洗浄装置。
（３）前記装置は、真空紫外光検出装置によって検出さ
れた洗浄室内の真空紫外線透過光量に基づいて、前記洗
浄室内を所望の酸素濃度に調整する手段を有することを
特徴とする上記（１）または上記（２）に記載の光学素
子の洗浄装置。
（４）前記装置は、圧力検出器によって検出された洗浄
室内の圧力状態に基づいて、前記洗浄室内を所望の圧力
に調整する手段を有することを特徴とする上記（１）〜
（３）のいずれかに記載の光学素子の洗浄装置。
（５）前記真空紫外光を照射する光源及び前記洗浄室
が、パージ容器に収容されていることを特徴とする上記
（１）〜（４）のいずれかに記載の光学素子の洗浄装
置。
（６）前記パージ容器は、真空紫外光を吸収しないガス
を供給するガス供給部及び該ガスを排出するガス排出部
を有することを特徴とする上記（５）に記載の光学素子
の洗浄装置。
（７）真空紫外光を照射して、洗浄室内に収容された被
洗浄物である光学素子表面の有機物等の汚染物を除去す
る光学素子の洗浄方法において、前記洗浄室内の酸素ガ
スの濃度を前記真空紫外光を吸収しないガスを供給する
ことによって調整し、前記洗浄室内を透過する真空紫外
光によって生成されるオゾン及び酸素ラジカルと、前記
酸素ガスの濃度調整に基づいて雰囲気中の酸素に吸収さ
れないで残った真空紫外光と、を用いて前記被洗浄物の
汚染を除去することを特徴とする光学素子の洗浄方法。
（８）前記酸素ガスの濃度調整が、酸素濃度検出器によ
って検出された洗浄室内の酸素濃度に基づいて行われる
ことを特徴とする上記（７）に記載の光学素子の洗浄方
法。
（９）前記酸素ガスの濃度調整が、前記洗浄室内の真空
紫外線透過光量をモニターすることによって行われるこ
とを特徴とする上記（７）に記載の光学素子の洗浄方
法。
（１０）前記洗浄室は、前記洗浄室内の圧力状態をモニ
ターすることにより、所望の圧力に調整されることを特
徴とする上記（７）〜（９）のいずれかに記載の光学素
子の洗浄方法。
（１１）前記被洗浄物の汚染物の除去が、前記真空紫外
光を照射する光源及び前記洗浄室を、パージ容器に収容
することによって行われることを特徴とする上記（７）
〜（１０）のいずれかに記載の光学素子の洗浄方法。
（１２）前記パージ容器に収容して行われる汚染物の除
去は、前記パージ容器内に真空紫外光を吸収しないガス
の供給・排出を介して行われることを特徴とする上記
（１１）に記載の光学素子の洗浄方法。
（１３）ブランクを加工して光学素子を形成する工程
と、上記（１）〜（６）のいずれかに記載の装置により
前記光学素子を洗浄する工程とを含む光学素子の製造方
法。The present invention provides the following (1).
(13) An optical element cleaning device, an optical element cleaning method, and an optical element manufacturing method configured as described in (13) above are provided. (1) In a cleaning device for an optical element, which irradiates vacuum ultraviolet light to remove contaminants such as organic substances on the surface of the optical element which is the object to be cleaned contained in the cleaning chamber, oxygen gas and vacuum ultraviolet light in the cleaning chamber. A gas that does not absorb light is supplied, and a supply / adjustment device that adjusts the concentration of the oxygen gas supplied to the cleaning chamber by the supply of the gas that does not absorb the vacuum ultraviolet light is used, and the oxygen gas has a predetermined oxygen concentration. An apparatus for cleaning an optical element, wherein the vacuum ultraviolet light can be applied to the object to be cleaned in a state adjusted to 1. (2) The apparatus according to (1) above, further comprising means for adjusting the inside of the cleaning chamber to a desired oxygen concentration based on the oxygen concentration inside the cleaning chamber detected by the oxygen concentration detector. Optical element cleaning device. (3) The apparatus includes means for adjusting the oxygen concentration in the cleaning chamber to a desired oxygen concentration based on the amount of transmitted vacuum ultraviolet light in the cleaning chamber detected by the vacuum ultraviolet light detection device. Alternatively, the optical element cleaning device according to (2) above. (4) The device has means for adjusting the pressure in the cleaning chamber to a desired pressure based on the pressure state in the cleaning chamber detected by the pressure detector.
The optical element cleaning device according to any one of (3). (5) The optical element cleaning apparatus according to any one of (1) to (4) above, wherein the light source for irradiating the vacuum ultraviolet light and the cleaning chamber are housed in a purge container. (6) The apparatus for cleaning an optical element according to (5), wherein the purge container has a gas supply unit that supplies a gas that does not absorb vacuum ultraviolet light and a gas discharge unit that discharges the gas. (7) In a method of cleaning an optical element, which comprises irradiating vacuum ultraviolet light to remove contaminants such as organic substances on the surface of the optical element that is the object to be cleaned contained in the cleaning chamber, the concentration of oxygen gas in the cleaning chamber is adjusted. Adjusted by supplying a gas that does not absorb the vacuum ultraviolet light, and absorbs ozone and oxygen radicals generated by the vacuum ultraviolet light passing through the cleaning chamber, and oxygen in the atmosphere based on the concentration adjustment of the oxygen gas. A method for cleaning an optical element, characterized in that the contamination of the object to be cleaned is removed by using vacuum ultraviolet light remaining without being processed. (8) The optical element cleaning method according to (7), wherein the oxygen gas concentration is adjusted based on the oxygen concentration in the cleaning chamber detected by the oxygen concentration detector. (9) The method for cleaning an optical element as described in (7) above, wherein the oxygen gas concentration is adjusted by monitoring the amount of vacuum ultraviolet light transmitted through the cleaning chamber. (10) Cleaning of the optical element according to any one of (7) to (9), wherein the cleaning chamber is adjusted to a desired pressure by monitoring a pressure state in the cleaning chamber. Method. (11) The contaminants on the object to be cleaned are removed by housing a light source for irradiating the vacuum ultraviolet light and the cleaning chamber in a purge container.
The method for cleaning an optical element according to any one of to (10). (12) The above-mentioned (11), characterized in that the contaminants contained in the purge container are removed through the supply / discharge of a gas that does not absorb vacuum ultraviolet light in the purge container. Method for cleaning optical elements. (13) A method of manufacturing an optical element, which includes a step of processing a blank to form an optical element, and a step of cleaning the optical element with the apparatus according to any one of (1) to (6).
【０００８】[0008]
【発明の実施の形態】光学素子表面の有機物等の汚染物
を除去するに際して、上記構成を適用して、洗浄室内の
酸素ガスの濃度をＮ2等の真空紫外領域（１５０〜２４
０ｎｍ）の光を吸収しないガスの供給によって調整する
ようにした洗浄装置で洗浄を行うと、曲率を有する立体
形状のレンズなどの光学素子及び基板の表面を一度にダ
メージを与えることなく効率的に洗浄でき、真空紫外領
域で吸収を持つ汚染物質を除去できる。また、これによ
ると、真空紫外レーザなどの高価装置が必要なく、酸素
ラジカルの濃度や真空紫外光の光量を適度に調節して洗
浄が行えるため、汚染物質の種類に応じて最適な洗浄条
件を設定し、安価に、安定した洗浄を行うことができ
る。BEST MODE FOR CARRYING OUT THE INVENTION When removing contaminants such as organic substances on the surface of an optical element, the above-mentioned structure is applied to adjust the concentration of oxygen gas in the cleaning chamber to a vacuum ultraviolet region (150 to 24) such as N 2.
When cleaning is performed with a cleaning device that is adjusted by supplying a gas that does not absorb (0 nm) light, the optical element such as a lens having a three-dimensional shape having a curvature and the surface of the substrate are efficiently damaged at one time. It can be cleaned and contaminants that absorb in the vacuum ultraviolet region can be removed. Further, according to this, since it is possible to perform cleaning by appropriately adjusting the concentration of oxygen radicals and the amount of vacuum ultraviolet light without requiring an expensive device such as a vacuum ultraviolet laser, the optimum cleaning conditions can be set according to the type of contaminant. It is possible to set and inexpensively perform stable cleaning.
【０００９】[0009]
【実施例】以下に、本発明の実施例について説明する。
［実施例１］図１は、本発明の実施例１に係る洗浄装置
の概略断面図である。本実施例にかかる洗浄装置は、真
空紫外領域の光を発するランプ１と、被洗浄物７を収容
する洗浄室２、前記洗浄室に酸素を導入する手段３１及
びＮ2ガスを供給する手段３２、洗浄室内の酸素濃度検
出器４、洗浄室内の酸素濃度に応じて酸素濃度を制御す
る制御装置５及びランプ１からの真空紫外光の減衰を防
止するためのパージ容器６を備えている。EXAMPLES Examples of the present invention will be described below. [Embodiment 1] FIG. 1 is a schematic sectional view of a cleaning apparatus according to Embodiment 1 of the present invention. The cleaning apparatus according to the present embodiment includes a lamp 1 that emits light in the vacuum ultraviolet region, a cleaning chamber 2 that contains an object to be cleaned 7, a means 31 that introduces oxygen into the cleaning chamber, and a means 32 that supplies N 2 gas. An oxygen concentration detector 4 in the cleaning chamber, a control device 5 for controlling the oxygen concentration according to the oxygen concentration in the cleaning chamber, and a purge container 6 for preventing the attenuation of vacuum ultraviolet light from the lamp 1 are provided.
【００１０】洗浄室２は密閉された構造を有しており、
ランプ１と被洗浄物との間には、真空紫外光を透過する
石英窓２１が設置されている。被洗浄物は表面が露出す
る状態でホルダー２２に積載され、洗浄される。洗浄室
２及び洗浄室２内の構造物は、被処理物の再汚染を防止
するため有機物等の汚染を放出しない材料で製作されて
いる。洗浄室２には酸素及び窒素の導入配管が接続され
ており、流量を制御された酸素及び窒素が導入される。
また、これらのガス排気配管２５も接続されており、排
気配管２５内の酸素濃度を酸素濃度検出器４で検出でき
る構成としている。さらに洗浄室２の圧力は圧力モニタ
ー２３で監視されており、排気配管２５に接続されてい
るコンダクタンス調整器２４を調整して排気配管２５の
コンダクタンスを調整することで、圧力の調整も可能と
している。ただし、再汚染を防止するために、真空ポン
プ等で排気し、減圧状態にすることはしない。The cleaning chamber 2 has a closed structure,
A quartz window 21 that transmits vacuum ultraviolet light is installed between the lamp 1 and the object to be cleaned. The object to be cleaned is loaded and cleaned on the holder 22 with its surface exposed. The cleaning chamber 2 and the structure inside the cleaning chamber 2 are made of a material that does not emit pollution such as organic matter in order to prevent recontamination of the object to be treated. Oxygen and nitrogen introduction pipes are connected to the cleaning chamber 2, and oxygen and nitrogen whose flow rates are controlled are introduced.
Further, these gas exhaust pipes 25 are also connected, and the oxygen concentration in the exhaust pipe 25 can be detected by the oxygen concentration detector 4. Further, the pressure in the cleaning chamber 2 is monitored by the pressure monitor 23. By adjusting the conductance adjuster 24 connected to the exhaust pipe 25 to adjust the conductance of the exhaust pipe 25, the pressure can be adjusted. . However, in order to prevent recontamination, the gas is not evacuated by a vacuum pump or the like to reduce the pressure.
【００１１】酸素濃度検出器の値は制御装置５により監
視されており、所定の濃度に調整するために、制御装置
５は酸素及び窒素流量を制御する。同時に制御装置５は
洗浄室内の圧力も監視し、排気配管のコンダクタンスを
調整して所定の圧力に維持できる。The value of the oxygen concentration detector is monitored by the control device 5, and the control device 5 controls the oxygen and nitrogen flow rates in order to adjust to a predetermined concentration. At the same time, the control device 5 also monitors the pressure in the cleaning chamber and can adjust the conductance of the exhaust pipe to maintain it at a predetermined pressure.
【００１２】ランプ１から放出された真空紫外光が効率
的に被洗浄物に照射されるよう、ランプ１及び洗浄室２
はパージ容器６内に納められており、パージ容器６には
Ｎ2等の真空紫外光を遮断しないガス導入口６１及び排
出口６２が設けられており、常にパージされ、容器内の
酸素濃度を酸素濃度検出器６３で監視している。このパ
ージ容器内においても、石英製の窓２１などの汚染を防
止するため、有機物等の汚染を放出しない材料で構成す
る。The lamp 1 and the cleaning chamber 2 are arranged so that the vacuum ultraviolet light emitted from the lamp 1 is efficiently applied to the object to be cleaned.
Is contained in a purge container 6, and the purge container 6 is provided with a gas inlet 61 and an outlet 62 that do not block vacuum ultraviolet light such as N 2 and is constantly purged to keep the oxygen concentration in the container constant. It is monitored by the oxygen concentration detector 63. Even in the purge container, in order to prevent the contamination of the quartz window 21 and the like, the purge container is made of a material that does not release the contamination such as organic substances.
【００１３】図１に示す光洗浄装置において、ランプと
して波長１７２ｎｍの真空紫外光を放射するキセノンエ
キシマランプを用いて両面研磨した蛍石基板を洗浄した
実施形態について説明する。蛍石基板の表面は、通常の
大気中に放置するだけで有機物などで汚染され、これら
の汚染物質の吸収によって、真空紫外領域の光の透過率
が劣化する現象が確認されている。このような表面汚染
は、コーティングを施した光学素子でもほぼ同様に認め
られており、近年の露光装置で使用されつつあるＡｒＦ
やＦ２エキシマレーザにおいても、このような吸収が生
じるため、透過率の劣化や吸収による発熱で露光性能に
悪影響を及ぼす原因となっている。コーティング後の光
学素子の汚染は、前記真空紫外エキシマレーザの照射で
分解除去されるため、大きな問題とならないケースもあ
るが、コーティングを行う前の基板表面の汚染は、膜の
吸収にも影響し、レーザの照射によっても容易に吸収が
低減しないため問題である。In the optical cleaning apparatus shown in FIG. 1, an embodiment in which a xenon excimer lamp that emits vacuum ultraviolet light having a wavelength of 172 nm is used as a lamp to clean a fluorite substrate whose both surfaces are polished will be described. It has been confirmed that the surface of the fluorite substrate is contaminated with organic substances and the like when left in ordinary air, and absorption of these pollutants deteriorates the transmittance of light in the vacuum ultraviolet region. Such surface contamination is recognized almost similarly in the coated optical element, and ArF, which is being used in recent exposure apparatuses, is observed.
Such absorption also occurs in the F 2 excimer laser and the like, so that the deterioration of the transmittance and the heat generated by the absorption adversely affect the exposure performance. Contamination of the optical element after coating is decomposed and removed by irradiation with the vacuum ultraviolet excimer laser in some cases, so there is no problem in some cases, but contamination of the substrate surface before coating also affects absorption of the film. However, the absorption is not easily reduced even by laser irradiation, which is a problem.
【００１４】そこで、成膜前の基板表面汚染の除去が特
に強く求められている。図２に厚さ２ｍｍの両面研磨蛍
石基板の透過率を示す。表面汚染の影響で真空紫外域の
吸収により、透過率の劣化が確認されている。この基板
表面のゴミ等を除去した後、洗浄室２内のホルダー２２
に設置する。ホルダー２２は基板に傷がつかず、さらに
洗浄室内で生成した酸素ラジカルなどが基板表面に容易
に到達できるよう、できるだけ基板が解放された状態で
保持できる構造としている。Therefore, there is a strong demand for removal of substrate surface contamination before film formation. FIG. 2 shows the transmittance of a double-sided polished fluorite substrate having a thickness of 2 mm. It has been confirmed that the transmittance is deteriorated due to absorption in the vacuum ultraviolet region due to the effect of surface contamination. After removing the dust on the substrate surface, the holder 22 in the cleaning chamber 2 is removed.
To install. The holder 22 has a structure in which the substrate is held in the opened state as much as possible so that the substrate is not damaged and oxygen radicals generated in the cleaning chamber can easily reach the surface of the substrate.
【００１５】つぎに、洗浄室２及びパージ容器６内を大
気圧以上のもとで、Ｎ2ガスでパージし、酸素濃度検出
器（４、６３）で残留酸素濃度を１ｐｐｍ以下に保持す
る。１ｐｐｍ以下になったところで酸素を導入する手段
３１より高純度酸素を、Ｎ2ガスを供給する手段３２か
ら高純度窒素を流量を制御して洗浄室２内に導入し、約
１％の酸素濃度になるように酸素濃度検出器４及び制御
装置５により調整する。この時、圧力モニター２３及び
コンダクタンス調整器２４によって、洗浄室２内は所定
の圧力（大気圧以上）に調整されている。Next, the cleaning chamber 2 and the purge container 6 are purged with N 2 gas under atmospheric pressure or more, and the residual oxygen concentration is kept at 1 ppm or less by the oxygen concentration detector (4, 63). High purity oxygen is introduced into the cleaning chamber 2 from a means 31 for introducing oxygen and a high purity nitrogen from means 32 for supplying N 2 gas at a flow rate of 1 ppm or less at a flow rate of about 1%. Is adjusted by the oxygen concentration detector 4 and the control device 5. At this time, the pressure monitor 23 and the conductance adjuster 24 adjust the inside of the cleaning chamber 2 to a predetermined pressure (atmospheric pressure or higher).
【００１６】ここで、キセノンエキシマランプ１を点灯
し、真空紫外光を蛍石等の洗浄基板に照射する。真空紫
外光は石英窓２１を通して蛍石基板に照射されるが途中
洗浄室２内の酸素ガスに吸収されてオゾンや酸素ラジカ
ルを生成すると共に、酸素濃度が低いため一部は蛍石基
板に直接照射される。この時、酸素ラジカルやキセノン
エキシマランプ１から発せられた真空紫外光によって、
表面汚染物質が分解、反応等により除去される。特に、
洗浄基板が蛍石等の透明材料であること及び酸素濃度を
基板の寸法、形状等によって制御することで、光の照射
面ばかりでなく、裏面側も同時に洗浄できることが確認
できた。特に厚く、曲率を有するレンズ等の洗浄には非
常に効果的である。図３（ａ）に３０分洗浄後の蛍石基
板の透過率を示す。基板の反転等をすることなく、表面
汚染を除去でき、良好な透過率が得られている。Here, the xenon excimer lamp 1 is turned on, and vacuum ultraviolet light is applied to the cleaning substrate such as fluorite. The vacuum ultraviolet light is applied to the fluorite substrate through the quartz window 21, but is absorbed by the oxygen gas in the cleaning chamber 2 on the way to generate ozone and oxygen radicals. Is irradiated. At this time, by the oxygen radicals and the vacuum ultraviolet light emitted from the xenon excimer lamp 1,
Surface contaminants are removed by decomposition, reaction, etc. In particular,
It was confirmed that the cleaning substrate was made of a transparent material such as fluorite and that the oxygen concentration was controlled by the size and shape of the substrate, so that not only the light irradiation surface but also the back surface could be cleaned at the same time. Especially, it is very effective for cleaning a thick lens having a curvature. FIG. 3A shows the transmittance of the fluorite substrate after washing for 30 minutes. Surface contamination can be removed without inverting the substrate, and good transmittance is obtained.
【００１７】窒素のみを導入し、１ｐｐｍ以下の酸素濃
度環境下で３０分洗浄を行った蛍石基板の透過率を図３
（ｂ）に示す。エキシマランプを３０分照射しただけで
は十分に洗浄できていないことがわかる。このように、
エキシマランプだけでは効率的に洗浄することができな
い。同様に、オゾンや酸素ラジカルのみの場合、有機物
汚染はある程度除去可能であるが十分ではない。酸素濃
度を制御し、真空紫外光を基板に同時に照射すること
で、真空紫外域に吸収を持つ汚染物質を効率的に除去す
ることが可能となる。特に、ランプからの距離に依存す
ることなく洗浄が行えるため、曲率を有するレンズなど
も効率的に洗浄することができる。FIG. 3 shows the transmittance of a fluorite substrate which was cleaned for 30 minutes in an oxygen concentration environment of 1 ppm or less by introducing nitrogen only.
It shows in (b). It can be seen that irradiating the excimer lamp for 30 minutes is not sufficient for cleaning. in this way,
Excimer lamps alone cannot be efficiently cleaned. Similarly, if only ozone or oxygen radicals are used, organic contaminants can be removed to some extent, but they are not sufficient. By controlling the oxygen concentration and irradiating the substrate with vacuum ultraviolet light at the same time, it becomes possible to efficiently remove contaminants having absorption in the vacuum ultraviolet region. In particular, since cleaning can be performed without depending on the distance from the lamp, a lens having a curvature can be efficiently cleaned.
【００１８】本実施例ではキセノンエキシマランプを用
いたが、Ａｒ2、Ｋｒ2，ＫｒＣｌ等のエキシマランプを
用いても、同様の効果が得られる。また、本実施例では
パージガスに窒素ガスを用いたが、洗浄に用いる真空紫
外領域に吸収を持たない汚染物質を含まないきれいなガ
スであればよく、Ｈｅ，Ｎｅ，Ａｒ等の不活性ガスを用
いてもよい。Although a xenon excimer lamp is used in this embodiment, the same effect can be obtained by using an excimer lamp made of Ar 2 , Kr 2 , KrCl or the like. Further, although nitrogen gas is used as the purge gas in this embodiment, any clean gas containing no contaminants having no absorption in the vacuum ultraviolet region used for cleaning may be used, and an inert gas such as He, Ne, Ar or the like may be used. May be.
【００１９】本実施例では石英窓２１を用いたが、真空
紫外光を透過する材料であればＣａＦ2、ＭｇＦ2などの
フッ化物やサファイアなどの酸化物でもよい。この時、
洗浄する基板の材料によっては短い波長の光によってダ
メージを受け、真空紫外光照射によって吸収が増大して
しまうこともある。このような場合、基板材料と同一材
質の窓材料を用いることで、ダメージを受ける短波長の
光をカットし、ダメージを防止することもできる。Although the quartz window 21 is used in this embodiment, a fluoride such as CaF 2 or MgF 2 or an oxide such as sapphire may be used as long as it is a material that transmits vacuum ultraviolet light. At this time,
Depending on the material of the substrate to be cleaned, it may be damaged by light of a short wavelength, and absorption may increase due to irradiation with vacuum ultraviolet light. In such a case, by using a window material made of the same material as the substrate material, it is possible to cut short-wavelength light that is damaged and prevent damage.
【００２０】［実施例２］図４は、本発明の実施例２に
かかる洗浄装置の概略断面図である。洗浄室２内に真空
紫外線モニター４１を設置し、洗浄室２内の真空紫外線
透過光量をモニターできる構成としている。このモニタ
ー値によって、制御装置５を介して洗浄室２内の酸素濃
度を調整できる。[Embodiment 2] FIG. 4 is a schematic sectional view of a cleaning apparatus according to Embodiment 2 of the present invention. A vacuum ultraviolet ray monitor 41 is installed in the cleaning chamber 2 so that the amount of transmitted vacuum ultraviolet ray in the cleaning chamber 2 can be monitored. With this monitor value, the oxygen concentration in the cleaning chamber 2 can be adjusted via the control device 5.
【００２１】ランプ１を点灯し、洗浄を開始すると、汚
染物質からＣＯ，ＣＯ2，Ｈ2Ｏなどのガスが生成する
が、汚染が多い場合、ガスも大量に発生し、真空紫外線
が吸収されて基板に照射される真空紫外線量が減少し、
安定した洗浄ができないケースも発生する。このような
構成を取ることによって、汚染物ガスの影響を酸素濃度
を調整することで排除でき、安定した洗浄が可能となっ
た。When the lamp 1 is turned on and cleaning is started, gases such as CO, CO 2 and H 2 O are produced from the pollutants. However, if there is a lot of contamination, a large amount of gas is also produced and vacuum ultraviolet rays are absorbed. The amount of vacuum ultraviolet rays radiated to the substrate is reduced,
In some cases, stable cleaning cannot be performed. By adopting such a configuration, the influence of pollutant gas can be eliminated by adjusting the oxygen concentration, and stable cleaning becomes possible.
【００２２】[0022]
【発明の効果】本発明によれば、被洗浄物である光学素
子に付着残留している有機物などの汚れを光学素子にダ
メージを与えることなく容易に取り除くことが可能とな
る光学素子の洗浄装置及び光学素子の洗浄方法、および
光学素子の製造方法を実現することができる。According to the present invention, an optical element cleaning device capable of easily removing stains such as organic substances attached to and remaining on an optical element, which is an object to be cleaned, without damaging the optical element. Further, it is possible to realize a method for cleaning an optical element and a method for manufacturing an optical element.
【図１】本発明の実施例１に係る洗浄装置の構成を示す
図。FIG. 1 is a diagram showing a configuration of a cleaning apparatus according to a first embodiment of the present invention.
【図２】２ｍｍ厚蛍石基板の分光透過率を示す図。FIG. 2 is a diagram showing the spectral transmittance of a 2 mm thick fluorite substrate.
【図３】（ａ）は実施例１によって洗浄された２ｍｍ厚
蛍石基板の分光透過率、（ｂ）は実施例１において酸素
を導入せずに洗浄した２ｍｍ厚蛍石基板の分光透過率を
示す図。3A is a spectral transmittance of a 2 mm thick fluorite substrate cleaned in Example 1, and FIG. 3B is a spectral transmittance of a 2 mm thick fluorite substrate cleaned in Example 1 without introducing oxygen. FIG.
【図４】本発明の実施例２に係る洗浄装置の構成を示す
図。FIG. 4 is a diagram showing a configuration of a cleaning apparatus according to a second embodiment of the present invention.
１：ランプ ２：洗浄室 ４：酸素濃度検出器 ５：制御装置 ６：パージ容器 ７：被洗浄物 ２１：石英窓 ２２：ホルダー ２３：圧力モニター ２４：コンダクタンス調整器 ２５：排気配管 ３１：酸素を導入する手段 ３２：Ｎ2ガスを供給する手段 ４１：真空紫外線モニター ６１：パージガス導入口 ６２：パージガス排出口 ６３：酸素濃度検出器1: Lamp 2: Cleaning chamber 4: Oxygen concentration detector 5: Control device 6: Purge container 7: Object to be cleaned 21: Quartz window 22: Holder 23: Pressure monitor 24: Conductance adjuster 25: Exhaust pipe 31: Oxygen Means for introducing 32: Means for supplying N 2 gas 41: Vacuum ultraviolet ray monitor 61: Purge gas inlet 62: Purge gas outlet 63: Oxygen concentration detector
Claims (13)
れた被洗浄物である光学素子表面の有機物等の汚染物を
除去する光学素子の洗浄装置において、 前記洗浄室内に酸素ガス及び真空紫外光を吸収しないガ
スを供給し、前記洗浄室内に供給された酸素ガスの濃度
を前記真空紫外光を吸収しないガスの供給によって調整
する供給・調整装置を有し、前記酸素ガスを所定の酸素
濃度に調整した状態で前記真空紫外光を前記被洗浄物に
照射可能としたことを特徴とする光学素子の洗浄装置。1. A cleaning device for an optical element for irradiating vacuum ultraviolet light to remove contaminants such as organic substances on the surface of the optical element which is the object to be cleaned contained in the cleaning chamber, wherein oxygen gas and oxygen gas are contained in the cleaning chamber. A gas that does not absorb vacuum ultraviolet light is supplied, and a supply / adjustment device that adjusts the concentration of the oxygen gas supplied to the cleaning chamber by the supply of a gas that does not absorb vacuum ultraviolet light is used. An apparatus for cleaning an optical element, which is capable of irradiating the object to be cleaned with the vacuum ultraviolet light in a state where the oxygen concentration is adjusted.
された洗浄室内の酸素濃度に基づいて、前記洗浄室内を
所望の酸素濃度に調整する手段を有することを特徴とす
る請求項１に記載の光学素子の洗浄装置。2. The apparatus according to claim 1, further comprising means for adjusting the inside of the cleaning chamber to a desired oxygen concentration based on the oxygen concentration inside the cleaning chamber detected by the oxygen concentration detector. Optical element cleaning device.
検出された洗浄室内の真空紫外線透過光量に基づいて、
前記洗浄室内を所望の酸素濃度に調整する手段を有する
ことを特徴とする請求項１または請求項２に記載の光学
素子の洗浄装置。3. The apparatus, based on the amount of transmitted vacuum ultraviolet light in the cleaning chamber detected by a vacuum ultraviolet light detector,
3. The optical element cleaning apparatus according to claim 1, further comprising means for adjusting the oxygen concentration in the cleaning chamber to a desired oxygen concentration.
た洗浄室内の圧力状態に基づいて、前記洗浄室内を所望
の圧力に調整する手段を有することを特徴とする請求項
１〜３のいずれか１項に記載の光学素子の洗浄装置。4. The apparatus according to claim 1, further comprising means for adjusting the pressure in the cleaning chamber to a desired pressure based on a pressure state in the cleaning chamber detected by a pressure detector. 2. A cleaning device for an optical element according to item 1.
浄室が、パージ容器に収容されていることを特徴とする
請求項１〜４のいずれか１項に記載の光学素子の洗浄装
置。5. The apparatus for cleaning an optical element according to claim 1, wherein the light source for irradiating the vacuum ultraviolet light and the cleaning chamber are housed in a purge container.
いガスを供給するガス供給部及び該ガスを排出するガス
排出部を有することを特徴とする請求項５に記載の光学
素子の洗浄装置。6. The apparatus for cleaning an optical element according to claim 5, wherein the purge container has a gas supply unit that supplies a gas that does not absorb vacuum ultraviolet light and a gas discharge unit that discharges the gas. .
れた被洗浄物である光学素子表面の有機物等の汚染物を
除去する光学素子の洗浄方法において、 前記洗浄室内の酸素ガスの濃度を前記真空紫外光を吸収
しないガスを供給することによって調整し、 前記洗浄室内を透過する真空紫外光によって生成される
オゾン及び酸素ラジカルと、前記酸素ガスの濃度調整に
基づいて雰囲気中の酸素に吸収されないで残った真空紫
外光と、を用いて前記被洗浄物の汚染を除去することを
特徴とする光学素子の洗浄方法。7. A method for cleaning an optical element, which comprises irradiating vacuum ultraviolet light to remove contaminants such as organic substances on the surface of the optical element, which is the object to be cleaned, contained in the cleaning chamber, wherein oxygen gas in the cleaning chamber is used. The concentration is adjusted by supplying a gas that does not absorb the vacuum ultraviolet light, and ozone and oxygen radicals generated by the vacuum ultraviolet light passing through the cleaning chamber, and oxygen in the atmosphere based on the concentration adjustment of the oxygen gas. A method for cleaning an optical element, comprising: removing the contamination of the object to be cleaned by using vacuum ultraviolet light that is not absorbed by the vacuum ultraviolet light.
器によって検出された洗浄室内の酸素濃度に基づいて行
われることを特徴とする請求項７に記載の光学素子の洗
浄方法。8. The method for cleaning an optical element according to claim 7, wherein the oxygen gas concentration is adjusted based on the oxygen concentration in the cleaning chamber detected by the oxygen concentration detector.
の真空紫外線透過光量をモニターすることによって行わ
れることを特徴とする請求項７に記載の光学素子の洗浄
方法。9. The method of cleaning an optical element according to claim 7, wherein the concentration of the oxygen gas is adjusted by monitoring the amount of vacuum ultraviolet light transmitted through the cleaning chamber.
をモニターすることにより、所望の圧力に調整されるこ
とを特徴とする請求項７〜９のいずれか１項に記載の光
学素子の洗浄方法。10. The optical element according to claim 7, wherein the cleaning chamber is adjusted to a desired pressure by monitoring a pressure state in the cleaning chamber. Cleaning method.
空紫外光を照射する光源及び前記洗浄室を、パージ容器
に収容することによって行われることを特徴とする請求
項７〜１０のいずれか１項に記載の光学素子の洗浄方
法。11. The removal of contaminants from the object to be cleaned is carried out by housing a light source for irradiating the vacuum ultraviolet light and the cleaning chamber in a purge container. The method for cleaning an optical element according to any one of items.
物の除去は、前記パージ容器内に真空紫外光を吸収しな
いガスの供給・排出を介して行われることを特徴とする
請求項１１に記載の光学素子の洗浄方法。12. The method according to claim 11, wherein the contaminants contained in the purge container are removed by supplying / discharging a gas that does not absorb vacuum ultraviolet light into the purge container. A method for cleaning an optical element as described above.
工程と、請求項１〜６のいずれか１項に記載の装置によ
り前記光学素子を洗浄する工程とを含む光学素子の製造
方法。13. A method of manufacturing an optical element, comprising: a step of processing a blank to form an optical element; and a step of cleaning the optical element with the apparatus according to claim 1.
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|---|---|---|---|
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2002154699A JP2003344601A (en) | 2002-05-28 | 2002-05-28 | Device and method for cleaning optical element and method for manufacturing it |
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| CN115103726A (en) * | 2020-04-09 | 2022-09-23 | 优志旺电机株式会社 | Method for decomposing nicotine |
| WO2024074443A1 (en) * | 2022-10-05 | 2024-04-11 | Carl Zeiss Smt Gmbh | Method and device for forming a fluoride or oxylfluoride layer for an optical element for the vuv wavelength range, and optical element comprising said fluoride or oxylfluoride layer |
| WO2024074440A1 (en) * | 2022-10-05 | 2024-04-11 | Carl Zeiss Smt Gmbh | Method and device for the post-treatment of a fluoride layer for an optical system for the vuv wavelength range, and optical element comprising said fluoride layer |
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