JPH04228560A - Dielectric multiplayer film nad its formation - Google Patents
Dielectric multiplayer film nad its formationInfo
- Publication number
- JPH04228560A JPH04228560A JP12926491A JP12926491A JPH04228560A JP H04228560 A JPH04228560 A JP H04228560A JP 12926491 A JP12926491 A JP 12926491A JP 12926491 A JP12926491 A JP 12926491A JP H04228560 A JPH04228560 A JP H04228560A
- Authority
- JP
- Japan
- Prior art keywords
- film
- multilayer film
- dielectric multilayer
- sio2
- substrate
- 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.)
- Pending
Links
- 230000015572 biosynthetic process Effects 0.000 title claims abstract description 11
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 83
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 42
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 38
- 239000011261 inert gas Substances 0.000 claims abstract description 12
- 238000004544 sputter deposition Methods 0.000 claims abstract description 11
- 239000000758 substrate Substances 0.000 claims description 28
- 239000000463 material Substances 0.000 claims description 15
- 238000000034 method Methods 0.000 claims description 14
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 12
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical group [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 11
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 10
- 239000007789 gas Substances 0.000 claims description 10
- 229910052786 argon Inorganic materials 0.000 claims description 6
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 6
- 150000002500 ions Chemical class 0.000 claims description 4
- 238000004140 cleaning Methods 0.000 claims description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 2
- 229910052710 silicon Inorganic materials 0.000 claims description 2
- 239000010703 silicon Substances 0.000 claims description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims 4
- 239000001301 oxygen Substances 0.000 claims 2
- 229910052760 oxygen Inorganic materials 0.000 claims 2
- 238000001755 magnetron sputter deposition Methods 0.000 claims 1
- 230000003287 optical effect Effects 0.000 abstract description 29
- 238000001228 spectrum Methods 0.000 abstract description 9
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 abstract description 7
- 229910001882 dioxygen Inorganic materials 0.000 abstract description 7
- 238000010521 absorption reaction Methods 0.000 abstract description 6
- 230000003685 thermal hair damage Effects 0.000 abstract description 2
- 239000010408 film Substances 0.000 description 112
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 12
- 229910052593 corundum Inorganic materials 0.000 description 12
- 229910001845 yogo sapphire Inorganic materials 0.000 description 12
- 229910018404 Al2 O3 Inorganic materials 0.000 description 11
- 238000010586 diagram Methods 0.000 description 11
- 239000012788 optical film Substances 0.000 description 10
- 230000003595 spectral effect Effects 0.000 description 9
- 238000010438 heat treatment Methods 0.000 description 7
- 239000010453 quartz Substances 0.000 description 4
- 229910001634 calcium fluoride Inorganic materials 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- BYFGZMCJNACEKR-UHFFFAOYSA-N aluminium(i) oxide Chemical compound [Al]O[Al] BYFGZMCJNACEKR-UHFFFAOYSA-N 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000010030 laminating Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000005566 electron beam evaporation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000005304 optical glass Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Landscapes
- Physical Vapour Deposition (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、紫外線等の大出力・高
繰り返しレ−ザ用光学部品の反射増加膜や反射防止膜等
を構成する誘電体多層膜およびその形成方法に関するも
のである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric multilayer film constituting a reflection increasing film, an antireflection film, etc. of an optical component for a high-output, high-repetition laser such as an ultraviolet ray, and a method for forming the same.
【０００２】0002
【従来の技術】誘電体多層膜は各種レーザ用光学部品等
（全反射鏡，ビームスプリッター，レンズ，窓材等）に
用いられているが、目標とする反射特性もしくは透過特
性を得るために光学基板表面に誘電体物質を真空蒸着法
等で積層し、反射防止膜や部分反射膜あるいは高反射膜
を構成することは一般技術として知られている。（例え
ば、久保田他「光学技術ハンドブック」）。[Prior Art] Dielectric multilayer films are used in various laser optical components (total reflection mirrors, beam splitters, lenses, window materials, etc.). It is known as a general technique to form an antireflection film, a partially reflective film, or a high reflection film by laminating a dielectric material on the surface of a substrate by vacuum evaporation or the like. (For example, Kubota et al. "Optical Technology Handbook").
【０００３】また、反射鏡としての多層膜構造は光学ガ
ラス基板上に、光学的膜厚がλ／４（λは注目する中心
波長）の高屈折率物質と低屈折率物質を交互に積層した
誘電体多層膜が採用されており、その層数および屈折率
の組合せによって任意の反射率の反射鏡が得られること
も良く知られている。[0003] In addition, the multilayer film structure as a reflecting mirror is made by alternately laminating high refractive index materials and low refractive index materials with an optical thickness of λ/4 (λ is the center wavelength of interest) on an optical glass substrate. It is also well known that a dielectric multilayer film is used, and that a reflecting mirror with an arbitrary reflectance can be obtained by combining the number of layers and the refractive index.
【０００４】0004
【発明が解決しようとする課題】しかしながら、高・低
屈折率物質として用いられる多くの酸化物は、抵抗加熱
法や電子ビーム蒸着法等の従来の蒸着方法や条件によっ
て熱分解が起こり低級酸化物に移行し、その結果吸収の
増加をもたらし、さらに屈折率や密度等の光学および物
理定数が大きく変化する。このように従来の多層膜形成
方法を用いて作製したレ−ザ用光学部品では耐光力が低
く、使用できるパワーレベルは高々１００Ｗ程度である
。また、破壊までに至らなくとも吸収光により発生した
熱により膜の屈折率や密度が変わりスペクトルが大きく
変化するという課題を有していた。[Problems to be Solved by the Invention] However, many oxides used as high and low refractive index materials undergo thermal decomposition due to conventional vapor deposition methods and conditions such as resistance heating and electron beam evaporation, resulting in lower oxides. , resulting in an increase in absorption, and further changes in optical and physical constants such as refractive index and density. As described above, laser optical parts manufactured using the conventional multilayer film forming method have low light resistance, and the usable power level is about 100 W at most. Further, even if the film does not break down, the heat generated by the absorbed light changes the refractive index and density of the film, causing a large change in the spectrum.
【０００５】さらに、紫外線領域で代表的なエキシマレ
ーザの出力が２ＫＷ，繰り返し数が１ＫＨｚともなると
、使用する光学部品にとっては、パルスレーザであるは
ずのエキシマレーザ光でも連続光と同様な熱ダメージを
受ける。それに加えて、従来より１桁以上高いレーザ光
が照射されることにより、光学部品にとって僅かな吸収
でも発生する熱が問題となる。ガラスや石英のような熱
伝導度の低い基板では、特にビーム照射部位の温度上昇
が激しくなり局所加熱が発生する。その結果、最初に光
学部品を構成している中で、一番熱に弱い多層膜部分の
破壊が起こり、次に基板等の熱変形が発生し、最後には
光学部品そのものが破壊されるという課題も有していた
。具体的には、従来法で作製され多層膜は３００℃加熱
でスペクトルが大幅に変化し、また膜のひび割れが発生
するという課題を有していた。Furthermore, when the output of a typical excimer laser in the ultraviolet region is 2 kW and the repetition rate is 1 kHz, the excimer laser light, which is supposed to be a pulsed laser, can cause the same thermal damage to the optical components used as continuous light. receive. In addition, since laser light is irradiated with laser light that is one order of magnitude higher than conventional laser light, heat generated even by a small amount of absorption becomes a problem for optical components. For substrates with low thermal conductivity, such as glass or quartz, the temperature rises especially at the beam irradiation site, causing local heating. As a result, first the multilayer film that makes up the optical component is the most vulnerable to heat is destroyed, then the substrate etc. is thermally deformed, and finally the optical component itself is destroyed. It also had its challenges. Specifically, multilayer films produced by conventional methods have the problem that their spectra change significantly when heated to 300° C., and cracks occur in the film.
【０００６】本発明は、上記従来技術の課題を解決する
もので、大出力・高繰り返しエキシマレーザ用光学部品
に使用でき、かつ光学部品が高温に曝されるような環境
の下でも使用できる十分な耐熱性を有した、反射増加膜
や反射防止膜等を構成する誘電体多層膜およびその形成
方法を提供することを目的とするものである。The present invention solves the above-mentioned problems of the prior art, and is capable of being used as an optical component for a high-output, high-repetition excimer laser, and is sufficiently usable even in an environment where the optical component is exposed to high temperatures. It is an object of the present invention to provide a dielectric multilayer film constituting a reflection increasing film, an antireflection film, etc., which has excellent heat resistance, and a method for forming the same.
【０００７】[0007]
【課題を解決するための手段】この目的を達成するため
に本発明は、光学研磨された基板表面を膜形成前に高真
空中で不活性ガスイオンを用いてイオン洗浄した後、ス
パッタリング法により高屈折率物質であるＡｌ２ Ｏ３
と低屈折率物質であるＳｉＯ２ を交互に積層するに
際し、高屈折率物質であるＡｌ２ Ｏ３ を形成する場
合は不活性ガス雰囲気中で、低屈折率物質であるＳｉＯ
２ を形成する場合には不活性ガスに酸素ガスを注入し
ながらスパッタリングする誘電体多層膜およびその形成
方法である。[Means for Solving the Problems] In order to achieve this object, the present invention cleans an optically polished substrate surface using inert gas ions in a high vacuum before forming a film, and then performs sputtering. Al2O3, a high refractive index material
When forming Al2O3, a high refractive index material, Al2O3, a low refractive index material, is alternately stacked with SiO2, a low refractive index material, in an inert gas atmosphere.
2 is a dielectric multilayer film and its formation method in which sputtering is performed while injecting oxygen gas into an inert gas.
【０００８】[0008]
【作用】本発明は上記形成方法により、低級酸化物に移
行しやすい低屈折物質である二酸化珪素（ＳｉＯ２ ）
膜を形成する場合のみスパッタリング用不活性ガスに酸
素ガスを注入することで膜の低級酸化物化を抑制し低吸
収率化を図り、さらに屈折率や密度等の光学および物理
定数を安定化することで、大出力・高繰り返しエキシマ
レーザ用光学部品に使用でき、かつ光学部品が高温に曝
されるような環境の下でも使用できる十分な耐熱性を有
した、反射増加膜や反射防止膜等を得ることができるも
のである。[Operation] The present invention uses the above-mentioned formation method to form silicon dioxide (SiO2), which is a low refractive substance that easily converts to lower oxides.
By injecting oxygen gas into the inert gas for sputtering only when forming a film, we suppress the formation of lower oxides in the film, lower the absorption rate, and further stabilize optical and physical constants such as refractive index and density. We are developing reflection-enhancing coatings, anti-reflection coatings, etc. that can be used in optical components for high-output, high-repetition excimer lasers, and have sufficient heat resistance to be used even in environments where optical components are exposed to high temperatures. It is something that can be obtained.
【０００９】[0009]
【実施例】（実施例１）以下本発明の第１実施例につい
て図面を参照しながら説明する。図１は本発明の一実施
例において、光学研磨された合成石英基板上に順次交互
に積層されたＳｉＯ２ 膜とＡｌ２ Ｏ３ 膜からなる
３６層（１８対）多層膜をスパッタリングガスの雰囲気
を変えて形成した場合の分光反射率特性を示した図であ
る。図１において、１は本発明による誘電体多層膜およ
びその形成方法に関し、ＳｉＯ２ 膜の形成時のみアル
ゴンガスに酸素ガスを１０％注入しながら形成した場合
の分光反射率特性であり、２はＳｉＯ２ 、Ａｌ２ Ｏ
３ 膜共にアルゴンガスのみで形成した場合の分光反射
率特性であり、３はＳｉＯ２ 、Ａｌ２ Ｏ３ 膜共に
アルゴンガスに酸素ガスを１０％注入しながら形成した
場合の分光反射率特性である。いずれも膜形成前にアル
ゴンガスイオンにより１．５×１０−５Ｔｏｒｒにてイ
オン洗浄を行った後、基板温度１５０℃に加熱し、スパ
ッタ時の全圧力２×１０−３Ｔｏｒｒ、投入パワーを１
．５ＫＷの条件で多層膜の成膜を行った。Embodiments (Embodiment 1) A first embodiment of the present invention will be described below with reference to the drawings. Figure 1 shows an embodiment of the present invention in which a 36-layer (18-pair) multilayer film consisting of SiO2 films and Al2O3 films stacked alternately on an optically polished synthetic quartz substrate was sputtered in different sputtering gas atmospheres. It is a figure showing the spectral reflectance characteristic when formed. In FIG. 1, 1 relates to the dielectric multilayer film and its forming method according to the present invention, and 2 is the spectral reflectance characteristic when the SiO2 film is formed while 10% oxygen gas is injected into the argon gas only when forming the SiO2 film. , Al2O
3 is the spectral reflectance characteristic when both films are formed using argon gas only, and 3 is the spectral reflectance characteristic when both the SiO2 and Al2 O3 films are formed while injecting 10% oxygen gas into argon gas. In both cases, before film formation, ion cleaning was performed with argon gas ions at 1.5 x 10-5 Torr, the substrate temperature was heated to 150°C, the total pressure during sputtering was 2 x 10-3 Torr, and the input power was 1.
．． A multilayer film was formed under the condition of 5KW.
【００１０】この図から判るように、酸化物の低級酸化
物への移行は高屈折率物質であるＡｌ２ Ｏ３ 膜より
低屈折率物質であるＳｉＯ２ 膜が激しい。ＳｉＯ２
膜を形成する場合にのみアルゴンガスに酸素ガスを注入
することによる本発明の成膜方法により、低級酸化物化
が抑制されるため散乱や吸収が少なく屈折率，密度の安
定した多層膜を得ることができる。なを、本実施例では
、多層膜の総数を偶数層（３６層）設けたが、奇数層と
しても同様の効果を得ることができる。As can be seen from this figure, the transition of oxides to lower oxides is more severe in the SiO2 film, which is a low refractive index material, than in the Al2 O3 film, which is a high refractive index material. SiO2
By using the film forming method of the present invention in which oxygen gas is injected into argon gas only when forming a film, formation of lower oxides is suppressed, so that a multilayer film with low scattering and absorption and stable refractive index and density can be obtained. I can do it. In this embodiment, the total number of multilayer films is an even number (36 layers), but the same effect can be obtained by using an odd number of layers.
【００１１】（実施例２）以下本発明の第２実施例につ
いて図面を参照しながら説明する。図２は本発明の一実
施例において光学研磨された炭化珪素（ＳｉＣ）基板上
に順次交互に積層されたＳｉＯ２ 膜とＡｌ２ Ｏ３
膜からなる４８層（２４対）多層膜のエキシマレーザ（
ＫｒＦ，ＡｒＦ，ＸｅＣｌ等）用反射鏡の構成、光学的
膜厚を示した図である。図２において、４は光学研磨さ
れた炭化珪素（ＳｉＣ）基板、５は全ての層の光学的膜
厚をλ／４（例えば、ＫｒＦエキシマレーザ（λ＝２４
８ｎｍ）用の場合には光学的膜厚は６２ｎｍとなる）に
したＳｉＯ２ 膜、６は全ての層の光学的膜厚をλ／４
にしたＡｌ２ Ｏ３ 膜、７はＳｉＯ２ 膜とＡｌ２
Ｏ３ 膜を交互に積層した４８層（２４対）の反射増加
膜である。図３は以上のように構成された多層膜からな
るＫｒＦエキシマレーザ用反射鏡の熱処理前後の分光反
射率特性を示した図である。８は加熱前と１００℃から
６００℃まで５０℃毎に各３０分間加熱した後の分光反
射率特性であり、９はその後７００℃と８００℃にて各
３０分間加熱した後の分光反射率特性である。いずれも
電気炉を用い大気中で加熱を行い冷却後に分光光度計に
より絶対反射率を測定した。(Embodiment 2) A second embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows SiO2 films and Al2O3 layers sequentially and alternately stacked on an optically polished silicon carbide (SiC) substrate in an embodiment of the present invention.
48 layers (24 pairs) multilayer excimer laser (
2 is a diagram showing the configuration and optical film thickness of a reflecting mirror for (KrF, ArF, XeCl, etc.); FIG. In FIG. 2, 4 is an optically polished silicon carbide (SiC) substrate, and 5 is an optically polished silicon carbide (SiC) substrate whose optical film thickness of all layers is λ/4 (for example, KrF excimer laser (λ=24
In the case of 8 nm), the optical thickness is 62 nm).
7 is a SiO2 film and Al2 film.
This is a reflection increasing film with 48 layers (24 pairs) of O3 films stacked alternately. FIG. 3 is a diagram showing the spectral reflectance characteristics of the KrF excimer laser reflector made of the multilayer film configured as described above before and after heat treatment. 8 shows the spectral reflectance characteristics before heating and after heating at 50°C from 100°C to 600°C for 30 minutes each, and 9 shows the spectral reflectance characteristics after heating at 700°C and 800°C for 30 minutes each. It is. In both cases, the samples were heated in the air using an electric furnace, and after cooling, the absolute reflectance was measured using a spectrophotometer.
【００１２】この図から判るように、８００℃までは加
熱しても分光スペクトルにほとんど変化が無く、耐熱性
の優れたＳｉＯ２ 非晶質膜とＡｌ２ Ｏ３ 非晶質膜
になっている。なお、多層膜のひび割れも発生しなかっ
た。また、本実施例では、光学研磨した基板に炭化珪素
（ＳｉＣ）を用いたが珪素（Ｓｉ），弗化カルシュウム
（ＣａＦ２ ），合成石英（ＳｉＯ２ ）を用いても同
様の反射増加膜を得ることができる。As can be seen from this figure, there is almost no change in the spectra even when heated up to 800° C., and the SiO2 amorphous film and Al2 O3 amorphous film have excellent heat resistance. In addition, no cracks occurred in the multilayer film. Furthermore, in this example, silicon carbide (SiC) was used for the optically polished substrate, but a similar reflection increasing film can also be obtained using silicon (Si), calcium fluoride (CaF2), or synthetic quartz (SiO2). I can do it.
【００１３】図４は本発明の多層膜および形成方法によ
り光学研磨された炭化珪素（ＳｉＣ）基板上に順次交互
に積層されたＳｉＯ２ 膜とＡｌ２Ｏ３ 膜からなる多
層膜の対数による反射率の変化を示した図である。この
図（図４）から明らかのように、本実施例による反射増
加膜は、少なくとも１８対（３６層）以上にすることで
反射率９９％を達成することが可能である。FIG. 4 shows the change in reflectance according to the logarithm of a multilayer film consisting of a SiO2 film and an Al2O3 film that are sequentially and alternately stacked on a silicon carbide (SiC) substrate that has been optically polished using the multilayer film and formation method of the present invention. FIG. As is clear from this figure (FIG. 4), the reflection increasing film according to this example can achieve a reflectance of 99% by providing at least 18 pairs (36 layers) or more.
【００１４】（実施例３）以下本発明の第３実施例につ
いて図面を参照しながら説明する。図５は本発明の一実
施例において光学研磨された炭化珪素（ＳｉＣ）基板上
に順次交互に積層されたＳｉＯ２ 膜とＡｌ２ Ｏ３
膜からなる４８層多層膜の構成、光学的膜厚を示した図
である。図５において、４は光学研磨された炭化珪素（
ＳｉＣ）基板、５は光学的膜厚をλ／４（たとえばＸｅ
Ｃｌエキシマレーザ（λ＝３０８ｎｍ）用の場合には光
学的膜厚は７７ｎｍとなる）にしたＳｉＯ２ 膜、６は
光学的膜厚をλ／４にしたＡｌ２ Ｏ３ 膜で、以上は
図２の構成と同様なものである。図２の構成と異なるの
はＳｉＯ２ 膜とＡｌ２ Ｏ３ 膜からなる最外対に調
整層１０を設けた点である。この調整層１０は、ＳｉＯ
２ 膜とＡｌ２ Ｏ３ 膜の光学的膜厚の和がλ／２（
たとえばＸｅＣｌエキシマレーザ（λ＝３０８ｎｍ）用
の場合には光学的膜厚は１５４ｎｍとなる）としながら
ＳｉＯ２ 膜とＡｌ２ Ｏ３ 膜それぞれの光学的膜厚
をλ／４からずらす（例えば、ＳｉＯ２ 膜の光学的膜
厚を３・λ／８、Ａｌ２ Ｏ３ 膜の光学的膜厚をλ／
８）ことによって調整層１０のそれぞれの膜の境界面で
の入射光の電界強度の最大値より低い値となる所に位置
させることができ、耐光力の向上が期待できる。(Embodiment 3) A third embodiment of the present invention will be described below with reference to the drawings. FIG. 5 shows SiO2 films and Al2O3 films sequentially and alternately stacked on an optically polished silicon carbide (SiC) substrate in an embodiment of the present invention.
FIG. 2 is a diagram showing the structure and optical thickness of a 48-layer multilayer film. In FIG. 5, 4 is optically polished silicon carbide (
SiC) substrate 5 has an optical film thickness of λ/4 (for example, Xe
6 is an SiO2 film with an optical thickness of 77 nm for a Cl excimer laser (λ = 308 nm), and 6 is an Al2 O3 film with an optical thickness of λ/4. The above is the configuration shown in Figure 2. It is similar to The difference from the configuration shown in FIG. 2 is that an adjustment layer 10 is provided on the outermost pair of the SiO2 film and the Al2 O3 film. This adjustment layer 10 is made of SiO
2 film and the Al2 O3 film is λ/2 (
For example, in the case of XeCl excimer laser (λ = 308 nm), the optical thickness is 154 nm), and the optical thickness of each of the SiO2 film and Al2 O3 film is shifted from λ/4 (for example, the optical thickness of the SiO2 film is 154 nm). The target film thickness is 3・λ/8, and the optical thickness of the Al2O3 film is λ/
8) As a result, the adjustment layer 10 can be positioned at a location where the electric field strength of the incident light has a lower maximum value than the maximum value at the interface between the respective films, and an improvement in light resistance can be expected.
【００１５】（実施例４）以下本発明の第４実施例につ
いて図面を参照しながら説明する。図６は本発明の一実
施例における光学研磨された弗化カルシュウム（ＣａＦ
２ ）基板上にＳｉＯ２ 膜、Ａｌ２ Ｏ３ 膜、Ｓｉ
Ｏ２ 膜の順に交互に積層された３層反射防止膜の構成
、光学的膜厚を示した図である。図６において、１１は
光学研磨された弗化カルシュウム（ＣａＦ２ ）基板、
１２は光学的膜厚がλ／４よりも所定量ずらした膜厚（
例えば、ＫｒＦエキシマレーザ（λ＝２４８ｎｍ）用の
場合には６２ｎｍより１０ｎｍずれた５２．０ｎｍ）の
第１層目のＳｉＯ２ 膜、１３は光学的膜厚がλ／４よ
りも所定量ずらした膜厚（例えば、ＫｒＦエキシマレー
ザ（λ＝２４８ｎｍ）用の場合には６２ｎｍより９．４
ｎｍずれた７１．４ｎｍ）の第２層目のＡｌ２ Ｏ３
膜、１４は光学的膜厚がλ／４よりも所定量ずらした膜
厚（例えば、ＫｒＦエキシマレーザ（λ＝２４８ｎｍ）
用の場合には６２ｎｍより４．４ｎｍずれた５７．６ｎ
ｍ）の第３層目のＳｉＯ２ 膜である。(Embodiment 4) A fourth embodiment of the present invention will be described below with reference to the drawings. FIG. 6 shows optically polished calcium fluoride (CaF) in one embodiment of the present invention.
2) SiO2 film, Al2O3 film, Si
FIG. 2 is a diagram showing the structure and optical film thickness of a three-layer antireflection film in which O2 films are alternately laminated in order. In FIG. 6, 11 is an optically polished calcium fluoride (CaF2) substrate;
12 is a film thickness whose optical film thickness is shifted by a predetermined amount from λ/4 (
For example, in the case of KrF excimer laser (λ = 248 nm), the first layer SiO2 film is 52.0 nm, which is 10 nm off from 62 nm, and 13 is a film whose optical thickness is shifted by a predetermined amount from λ/4. Thickness (for example, for KrF excimer laser (λ = 248 nm), 9.4 nm from 62 nm
71.4 nm) second layer Al2O3
The film 14 is a film whose optical film thickness is shifted by a predetermined amount from λ/4 (for example, KrF excimer laser (λ=248 nm)
57.6n, which is 4.4nm off from 62nm
This is the third layer of SiO2 film of m).
【００１６】次に、本膜厚構成により得られる効果につ
いて説明する。図７に反射スペクトルの結果を示す。１
５はそれぞれの光学的膜厚を前記値に一致させた場合の
反射スペクトル、１６はそれぞれの光学的膜厚を前記値
より５％増加させた場合の反射スペクトル、１７はそれ
ぞれの光学的膜厚を前記値より５％減少させた場合の反
射スペクトルを示した図である。この図（図７）から明
らかのように、本実施例による反射防止膜は、それぞれ
の光学的膜厚を前記値に対して５％増減しても反射率０
．５％以下を達成することが可能である。Next, the effects obtained by this film thickness configuration will be explained. Figure 7 shows the results of the reflection spectrum. 1
5 is a reflection spectrum when each optical film thickness is made to match the above value, 16 is a reflection spectrum when each optical film thickness is increased by 5% from the above value, and 17 is each optical film thickness. FIG. 3 is a diagram showing a reflection spectrum when the value is decreased by 5% from the above value. As is clear from this figure (FIG. 7), the antireflection film according to this example has a reflectance of 0 even if the optical film thickness is increased or decreased by 5% from the above value.
．． It is possible to achieve less than 5%.
【００１７】なを、本実施例では、光学研磨した基板に
弗化カルシュウム（ＣａＦ２ ）を用いたが合成石英（
ＳｉＯ２ ）を用いても同様の反射防止膜を得ることが
可能である。In this example, calcium fluoride (CaF2) was used for the optically polished substrate, but synthetic quartz (CaF2) was used for the optically polished substrate.
It is also possible to obtain a similar antireflection film using SiO2).
【００１８】また、本実施例においても前実施例におい
て説明したと同様な耐熱性を有することはもちろんであ
る。It goes without saying that this example also has the same heat resistance as described in the previous example.
【００１９】[0019]
【発明の効果】以上のように本発明は、ＳｉＯ２ 膜を
形成する場合にのみ不活性がスに酸素ガスを注入するこ
とにより、ＳｉＯ２ 膜の低級酸化物への移行を抑制し
低吸収率化を図り、さらに屈折率や密度，ストレス等の
光学および物理定数を安定化することが出来、その結果
耐光力が向上し大出力・高繰り返しエキシマレーザ用光
学部品に使用でき、かつ光学部品が高温に曝されるよう
な環境の下でも使用できる十分な耐熱性を有した高反射
膜、反射防止膜等を得ることができるので、その効果は
大である。As described above, the present invention suppresses the transition of the SiO2 film to lower oxides and lowers the absorption rate by injecting oxygen gas into the inert gas only when forming the SiO2 film. In addition, optical and physical constants such as refractive index, density, and stress can be stabilized, resulting in improved light resistance and can be used in optical components for high-output, high-repetition excimer lasers, and optical components can be used at high temperatures. The effect is great because it is possible to obtain a highly reflective film, an antireflection film, etc. that has sufficient heat resistance to be used even in an environment where it is exposed to.
【図１】第１図は本発明の第１の実施例における合成石
英基板上にＳｉＯ２膜とＡｌ２ Ｏ３ 膜からなる３６
層（１８対）多層膜をスパッタリングガスの雰囲気を変
えて形成した場合の分光反射率特性図[Fig. 1] Fig. 1 shows a 36-layer structure consisting of a SiO2 film and an Al2 O3 film on a synthetic quartz substrate in the first embodiment of the present invention.
Spectral reflectance characteristic diagram when a multilayer film (18 pairs) is formed by changing the sputtering gas atmosphere
【図２】第２図は本発明の第２の実施例における光学研
磨された炭化珪素（ＳｉＣ）基板上に順次交互に積層さ
れたＳｉＯ２ 膜とＡｌ２ Ｏ３ 膜からなる４８層（
２４対）多層膜のエキシマレーザ用反射鏡の構成図FIG. 2 shows 48 layers (48 layers) consisting of SiO2 films and Al2O3 films stacked sequentially and alternately on an optically polished silicon carbide (SiC) substrate in a second embodiment of the present invention.
24 pairs) Configuration diagram of multilayer excimer laser reflector
【図
３】第３図は本発明の第２の実施例における多層膜から
なるＫｒＦエキシマレーザ用反射鏡の熱処理前後の分光
反射率特性図[Fig. 3] Fig. 3 is a spectral reflectance characteristic diagram before and after heat treatment of a KrF excimer laser reflector made of a multilayer film according to the second embodiment of the present invention.
【図４】第４図は本発明の第２の実施例における光学研
磨された炭化珪素（ＳｉＣ）基板上に本発明の多層膜お
よび形成方法により順次交互に積層されたＳｉＯ２ 膜
とＡｌ２ Ｏ３ 膜からなる多層膜の対数による反射率
の変化図FIG. 4 shows a SiO2 film and an Al2 O3 film that are sequentially and alternately laminated by the multilayer film and formation method of the present invention on an optically polished silicon carbide (SiC) substrate in a second embodiment of the present invention. Change diagram of reflectance due to logarithm of multilayer film consisting of
【図５】第５図は本発明の第３の実施例における光学研
磨された炭化珪素（ＳｉＣ）基板上に順次交互に積層さ
れたＳｉＯ２ 膜とＡｌ２ Ｏ３ 膜からなる４８層多
層膜の構成図FIG. 5 is a configuration diagram of a 48-layer multilayer film consisting of SiO2 films and Al2 O3 films sequentially and alternately laminated on an optically polished silicon carbide (SiC) substrate in a third embodiment of the present invention.
【図６】第６図は本発明の第４の実施例における光学研
磨された弗化カルシュウム（ＣａＦ２ ）基板上にＳｉ
Ｏ２ 膜、Ａｌ２ Ｏ３ 膜、ＳｉＯ２ 膜の順に交互
に積層されたＫｒＦエキシマレーザ用の３層反射防止膜
の構成図FIG. 6 shows Si on an optically polished calcium fluoride (CaF2) substrate in the fourth embodiment of the present invention.
A configuration diagram of a three-layer antireflection film for KrF excimer lasers, in which O2 film, Al2 O3 film, and SiO2 film are alternately laminated in this order.
【図７】第７図は本発明の第４の実施例におけ
る光学研磨された弗化カルシュウム（ＣａＦ２ ）基板
上にＳｉＯ２ 膜、Ａｌ２ Ｏ３ 膜、ＳｉＯ２ 膜の
順に交互に積層されたＫｒＦエキシマレーザ用の３層反
射防止膜の反射スペクトルの結果図FIG. 7 shows a KrF excimer laser in which SiO2 films, Al2O3 films, and SiO2 films are alternately laminated in this order on an optically polished calcium fluoride (CaF2) substrate according to a fourth embodiment of the present invention. Figure of reflection spectrum results of three-layer anti-reflection film
４ 基板 ５ ２酸化珪素膜 ６ 酸化アルミニウム膜 ７ 反射増加膜 １０ 調整層 １１ 基板 １２ ２酸化珪素膜 １３ 酸化アルミニウム膜 １４ ２酸化珪素膜 4 Board 5 Silicon dioxide film 6 Aluminum oxide film 7 Reflection increasing film 10 Adjustment layer 11 Board 12 Silicon dioxide film 13 Aluminum oxide film 14 Silicon dioxide film
Claims (8)
ング法により、不活性ガスを用い高屈折率物質として酸
化アルミニウム（Ａｌ２ Ｏ３ ）および不活性がスに
酸素（Ｏ２ ）ガスを注入しながら低屈折率物質として
二酸化珪素（ＳｉＯ２ ）を交互に積層することを特徴
とする誘電体多層膜。1. A sputtering method is applied to the surface of an optically polished substrate using aluminum oxide (Al2O3) as a high refractive index material using an inert gas and a low refractive index material while injecting oxygen (O2) gas into the inert gas. A dielectric multilayer film characterized by alternately stacking silicon dioxide (SiO2) as a material.
防止膜であることを特徴とする請求項１記載の誘電体多
層膜。2. The dielectric multilayer film according to claim 1, wherein the dielectric multilayer film is a reflection increasing film or an antireflection film.
），珪素（Ｓｉ），弗化カルシュウム（ＣａＦ２ ），
合成石英（ＳｉＯ２ ）から選択されることを特徴とす
る請求項２記載の誘電体多層膜。3. The substrate of the reflection increasing film is silicon carbide (SiC).
), silicon (Si), calcium fluoride (CaF2),
3. The dielectric multilayer film according to claim 2, wherein the dielectric multilayer film is selected from synthetic quartz (SiO2).
（ＣａＦ２ ），合成石英（ＳｉＯ２ ）から選択され
ることを特徴とする請求項２記載の誘電体多層膜。4. The dielectric multilayer film according to claim 2, wherein the substrate of the antireflection film is selected from calcium fluoride (CaF2) and synthetic quartz (SiO2).
スパッタリング法を用いたことを特徴とする請求項１記
載の誘電体多層膜。5. The dielectric multilayer film according to claim 1, wherein the sputtering method uses a magnetron sputtering method.
であることを特徴とする請求項１記載の誘電体多層膜。6. The dielectric multilayer film according to claim 1, wherein the inert gas is argon (Ar) gas.
ング法により、不活性ガスを用い高屈折率物質として酸
化アルミニウム（Ａｌ２ Ｏ３ ）、不活性ガスに酸素
（Ｏ２ ）ガスを注入しながら低屈折率物質として二酸
化珪素（ＳｉＯ２ ）を交互に積層することを特徴とす
る誘電体多層膜の形成方法。7. Aluminum oxide (Al2O3) is used as a high refractive index material using an inert gas, and a low refractive index material is added to the surface of the optically polished substrate by sputtering while injecting oxygen (O2) gas into the inert gas. A method for forming a dielectric multilayer film, characterized in that silicon dioxide (SiO2) is alternately laminated as a layer.
於いて、膜形成時のスパッタリング中の真空度より高真
空度下で不活性ガスを用いたイオンによるクリーニング
をおこなう事を特徴とする請求項７記載の誘電体多層膜
の形成方法。8. A claim characterized in that, in cleaning the substrate surface before film formation, cleaning is performed with ions using an inert gas under a vacuum degree higher than that during sputtering during film formation. 7. The method for forming a dielectric multilayer film according to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12926491A JPH04228560A (en) | 1990-09-25 | 1991-05-31 | Dielectric multiplayer film nad its formation |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2-255833 | 1990-09-25 | ||
| JP25583390 | 1990-09-25 | ||
| JP12926491A JPH04228560A (en) | 1990-09-25 | 1991-05-31 | Dielectric multiplayer film nad its formation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04228560A true JPH04228560A (en) | 1992-08-18 |
Family
ID=26464714
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12926491A Pending JPH04228560A (en) | 1990-09-25 | 1991-05-31 | Dielectric multiplayer film nad its formation |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04228560A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6261696B1 (en) | 1996-03-22 | 2001-07-17 | Canon Kabushika Kaisha | Optical element with substrate containing fluorite as main ingredient, and method and apparatus for producing the optical element |
-
1991
- 1991-05-31 JP JP12926491A patent/JPH04228560A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6261696B1 (en) | 1996-03-22 | 2001-07-17 | Canon Kabushika Kaisha | Optical element with substrate containing fluorite as main ingredient, and method and apparatus for producing the optical element |
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