TWI647545B

TWI647545B - Manufacturing method of optical element, exposure device and article

Info

Publication number: TWI647545B
Application number: TW106136870A
Authority: TW
Inventors: 井本浩平
Original assignee: 日商佳能股份有限公司
Priority date: 2016-11-22
Filing date: 2017-10-26
Publication date: 2019-01-11
Also published as: CN108089407A; TW201820054A; JP2018084637A; KR102230464B1; CN108089407B; JP6862154B2; KR20180057525A

Abstract

本發明涉及光學元件、曝光裝置以及物品的製造方法。提供有利於校正如具有多個反曲點的複雜的變形的光學元件。光學元件（2）具備：反射鏡（21），具有設置有反射膜的光學面（21a）及與光學面（21a）相反側的非光學面（21b）；以及多個校正膜（23），設置於非光學面（21b）側，用於校正反射鏡（21）的形狀。多個校正膜（23）在非光學面（21b）側被分開設置於彼此不同的多個區域。The present invention relates to an optical element, an exposure device, and a method for manufacturing an article. An optical element is provided that facilitates correcting complex deformations such as having multiple inflection points. The optical element (2) includes a reflecting mirror (21) having an optical surface (21a) provided with a reflective film and a non-optical surface (21b) opposite to the optical surface (21a); and a plurality of correction films (23), The non-optical surface (21b) is provided to correct the shape of the mirror (21). The plurality of correction films (23) are separately provided on a plurality of regions different from each other on the non-optical surface (21b) side.

Description

光學元件、曝光裝置及物品之製造方法Manufacturing method of optical element, exposure device and article

[0001] 本發明涉及光學元件、曝光裝置以及物品的製造方法。[0001] The present invention relates to an optical element, an exposure device, and a method for manufacturing an article.

[0002] 在半導體的製造中使用的投影曝光裝置中，為了應對曝光時的溫度變化所致的像差的劣化，有使在光學系統中使用的反射鏡的反射面的形狀可變來校正像差的技術。形狀可變的光學元件的厚度形成得較薄（例如5mm左右）以使得易於變形，但根據其薄度，由於各種主要原因，元件可能變形。　　[0003] 一般，作為校正反射鏡的變形的方法，有如下方法：在反射鏡的與反射面（即光學面）相反側的非光學面形成薄膜，利用非光學面的內部應力來抵消光學面側的內部應力，從而校正反射鏡的變形。例如，在專利文獻1記載的方法中，使用用於控制膜厚分布的控制板，根據部位按照任意的厚度對非光學面的薄膜進行成膜，來校正光學元件的變形。　　[先前技術文獻] 　　[專利文獻] 　　[0004] 專利文獻1：日本特開2005-19485號公報[0002] In a projection exposure apparatus used in the manufacture of semiconductors, in order to cope with the deterioration of aberrations caused by temperature changes during exposure, there is a method of correcting an image by changing the shape of a reflecting surface of a mirror used in an optical system. Poor technology. The thickness of the variable shape optical element is formed to be thin (for example, about 5 mm) so as to be easily deformed, but depending on its thinness, the element may be deformed due to various reasons. [0003] In general, as a method of correcting the distortion of a mirror, there is a method of forming a thin film on a non-optical surface of the mirror opposite to the reflective surface (that is, an optical surface), and using the internal stress of the non-optical surface to cancel the optical surface. The internal stress on the side, thus correcting the distortion of the mirror. For example, in the method described in Patent Document 1, a control plate for controlling the film thickness distribution is used to form a thin film having a non-optical surface with an arbitrary thickness according to a portion to correct distortion of an optical element. [Prior Art Document] [Patent Document] [0004] Patent Document 1: Japanese Patent Laid-Open No. 2005-19485

[發明所欲解決之課題] 　　[0005] 然而，在專利文獻1的使用膜厚分布控制板的方法中，如果光學元件的變形是如球面變形的低次的變形則能夠校正，但在對如具有多個反曲點的複雜的變形進行校正的情況下不利。　　[0006] 本發明的目的在於例如提供對於校正如具有多個反曲點的複雜的變形有利的光學元件。　　[解決課題之手段] 　　[0007] 為了解決上述課題，本發明的光學元件具備：光學元件主體，具有設置有反射膜的光學面、及與光學面相反側的非光學面；以及多個校正膜，設置於非光學面側，用於校正光學元件主體的形狀，多個校正膜在非光學面側被分開設置於彼此不同的多個區域。　　[發明功效] 　　[0008] 根據本發明，例如能夠提供在校正如具有多個反曲點的複雜的變形方面有利的光學元件。[Problems to be Solved by the Invention] 000 [0005] However, in the method using the film thickness distribution control plate of Patent Document 1, if the deformation of the optical element is a low-order deformation such as a spherical deformation, it can be corrected. It is disadvantageous when a complicated deformation having a plurality of inflection points is corrected. [0006] An object of the present invention is to provide, for example, an optical element that is advantageous for correcting a complex deformation such as having a plurality of inflection points. [Means for Solving the Problems] [0007] In order to solve the above-mentioned problems, an optical element of the present invention includes an optical element body having an optical surface provided with a reflective film, a non-optical surface opposite to the optical surface, and a plurality of correction films. Is provided on the non-optical surface side for correcting the shape of the main body of the optical element, and a plurality of correction films are separately provided on the non-optical surface side in a plurality of regions different from each other. [Effect of Invention] [0008] According to the present invention, for example, it is possible to provide an optical element that is advantageous in correcting a complex deformation such as having a plurality of inflection points.

[0010] 以下，參照附圖，詳細說明用於實施本發明的方式。在以下的實施方式中，作為光學元件的一個例子，以反射鏡為例子進行說明，但即使將反射鏡置換為其它光學元件（棱鏡、透鏡）等，其效果也相同。　　[0011] 　　[第一實施方式] 　　圖1是示出本發明的第一實施方式所涉及的光學元件2的結構的概略剖面圖。光學元件2具備：反射鏡（即光學元件主體）21，具有使光反射的光學面21a及與光學面21a相反側的非光學面21b；以及作為第一膜的校正膜23，設置於非光學面21b，用於校正反射鏡21的形狀的變形。校正膜23如後所述，由多個膜區域23-n構成。另外，光學元件2在光學面21a具備改善光學功能的作為第二膜的反射膜22。反射鏡21例如使用使光學面的形狀可變的可變形狀光學元件。　　[0012] 圖2是示出使光學元件2變形的可變形狀光學元件單元1的結構的概略剖面圖。在光學元件2中，在作為反射鏡21的表面的光學面形成反射膜22，在作為反射鏡21的背面的非光學面形成校正膜23。光學元件2經由保持構材31被安裝於基座3。另外，在作為光學元件2的非光學面側的背面配置有對反射鏡21變形驅動的多個致動器4。通過驅動致動器4，反射鏡21變形為期望的形狀。　　[0013] 在半導體製造中的將光罩（遮罩）上的圖案轉印到晶圓的光刻程序中，為了使非常微細的圖案在晶圓上成像，光學系統的像差等的影響成為問題。在進行光刻程序的半導體曝光裝置中，通過使用使光學系統的透鏡、反射鏡變形的可變形狀光學元件，能夠改善成像特性。　　[0014] 一般，在要求高精度的形狀精度的光學元件中，為了應對重力所致的變形、從鏡筒受到的變形等，設計成盡可能增大光學元件的厚度來提高剛性。　　[0015] 相對於此，在可變形狀光學元件的情況下，如圖2所示，一般地在較薄且易於變形的光學元件2中配置多個致動器4，使光學元件2變形來控制光學元件2的形狀。這樣，在可變形狀光學元件中，通過致動器4使光學元件2自身變形，所以設計成使光學元件2的厚度變薄來降低剛性。光學元件2通過降低剛性來降低致動器4的推力，降低致動器4的浪費的發熱、致動器4的推力所致的其它構造體的變形這樣的壞影響。　　[0016] 如圖1所示，在使用可變形狀光學元件的反射鏡21中，為了改善光學特性，在光學面21a設置抗反射膜、反射膜22這樣的光學薄膜。光學薄膜一般是包括多個材料層的多層膜，熱膨脹率與反射鏡21不同。因此，由於溫度變化，反射鏡21和光學薄膜呈現如雙金屬那樣的變形。　　[0017] 另外，通過使用蒸鍍、濺鍍等成膜手段使光學薄膜形成於反射鏡21，在反射鏡21與光學薄膜之間產生內部應力，使光學元件2變形。　　[0018] 在半導體曝光裝置中使用的可變形狀光學元件要求非常高的形狀精度。因此，上述光學薄膜的成膜所致的變形、光學薄膜和反射鏡21的溫度變化所致的變形對光學性能造成影響。　　[0019] 對於成膜所致的變形，有通過光學薄膜的成膜降低內部應力的方法。但是，為了降低內部應力，需要變更在光學上理想的多層的光學薄膜的結構以用於降低內部應力，相比於理想的光學薄膜，光學性能劣化。　　[0020] 對於反射鏡21和光學薄膜的熱膨脹率差所致的變形，有高度地管理溫度的方法，但在曝光裝置中，高強度的曝光光入射到反射鏡21，所以溫度的管理困難。　　[0021] 作為其它手段，如圖2所示，有驅動致動器4來校正反射鏡21的變形的方法。但是，光學薄膜的內部應力所致的變形的校正為偏置校正，所以需要將致動器4的受限的行程、推力分出到變形的校正。　　[0022] 光學薄膜的內部應力對溫度、濕度等敏感，隨著時間變化。因此，即使能夠通過致動器4校正向可變形狀光學元件形成光學薄膜時的變形，針對之後的裝置運用時等的進一步的變形，需要測量可變形狀光學元件的形狀。可變形狀光學元件的形狀測量有成本等各種制約，所以最好不進行形狀測量而開放式驅動致動器4。然而，在致動器4的開放式驅動中，難以校正光學薄膜的內部應力的變動、熱膨脹所致的變形。　　[0023] 例如，如圖3所示的在簡單的圓板玻璃6形成有薄膜25的光學元件的情況下的內部應力所致的變形成為使圓板按照球狀彎曲的簡單的曲率變化。因此，膜應力變形能夠通過光學元件的配置調整來校正，或者能夠由圖2所示的致動器4進行驅動校正。　　[0024] 相對於此，如圖4所示，在有效面具有曲率並且厚度不恒定的可變形狀光學元件24中，在形成均勻的厚度的薄膜25時，薄膜25的內部應力/熱膨脹所致的變形呈現2次以上的不易校正的高次變形。因此，在光學元件的配置的調整中無法修正，另外，在使可變形狀光學元件24變形的致動器4的驅動中分辨率不足。　　[0025] 在本實施方式中，通過控制在光學元件的非光學面形成的校正膜的分布狀態來解決上述問題。具體而言，例如如圖1所示，在可變形狀的反射鏡21的非光學面21b設置從反射鏡21的中心按照同心圓狀分割成多個區域的校正膜23。即，校正膜23在非光學面21b中被分開設置於多個膜區域23-1、23-2、23-3、･････23-n、･････。在此，能夠考慮膜的內部應力分布等，將任意的膜區域23-j和與其鄰接的膜區域23-k的間隔d（j-k）設定為任意的寬度。另外，在本實施方式中，在比膜區域23-j以及23-k更外側形成的膜區域23-x和與其鄰接的膜區域23-y的間隔d（x-y）形成得比上述間隔d（j-k）大，兩者的間隔設為不同。　　[0026] 在本實施方式中，通過調整有無成膜，對內部應力提供分布。在校正膜23中，任意的膜區域23-j和與其鄰接的膜區域23-k之間為不存在膜的非膜區域28。為了在校正膜23的成膜中形成該非膜區域28，設置圖5的（A）所示的遮蔽26。在通過遮蔽26形成校正膜23時，能夠形成如圖5的（B）所示的非膜區域28。遮蔽26可以是一般的遮蔽帶、防止膜附著的材料。但是，存在由於遮蔽26所致的使成膜真空槽的高度真空環境發生化學污染的擔心，所以最好是化學污染少的物質。　　[0027] 圖6是示出使非光學面的校正膜23的厚度在整個面均勻的情況下的、膜的內部應力所致的反射鏡21的變形狀態的概略剖面圖。反射鏡21的厚度隨著向外周而變薄，所以反射鏡21和膜的內部應力所致的雙金屬效果根據反射鏡21的厚度而變化。另外，由於反射鏡21是曲面，根據半徑方向的位置，內部應力所致的雙金屬效果變化。因此，即使在反射鏡21的光學面以及非光學面這兩面整體形成均勻的膜，仍殘留如圖6所示的非線性的變形。　　因此，在圖6的對變形產生影響的校正膜23中，通過對內部應力附加分布以校正變形，能夠抑制反射鏡的變形。　　[0028] 圖7是用於根據膜應力所致的反射鏡21的變形求出遮蔽的配置的圖。圖7的（A）是校正膜23的厚度均勻的情況下的反射鏡21的變形狀態，圖7的（B）是圖7的（A）的變形量，圖7的（C）是用於提供用於校正圖7的（B）的變形的內部應力分布的遮蔽26的配置圖。　　[0029] 在校正膜23中產生的內部應力不管半徑如何都是恒定的，但由於反射鏡21是曲面且厚度不均勻，所以反射鏡21呈現如圖7的（B）所示的不均勻的變形。在圖7的（B）中的K的範圍中，反射膜22的影響大於校正膜23的影響，所以反射鏡21在反射膜側呈現凸的變形。另一方面，在圖7的（B）中的L的範圍中，校正膜23的影響大於反射膜22的影響，所以反射鏡21在校正膜側呈現凸的變形。即，如果能夠在K的範圍中增加校正膜23的內部應力，在L的範圍中降低校正膜23的內部應力，則能夠校正圖7的（B）所示的反射鏡21的變形。　　[0030] 針對K和L各自的區域，通過圖7的（C）所示的遮蔽26進行校正膜23的內部應力的控制。在希望降低校正膜23的內部應力的地方使遮蔽26的半徑方向的寬度變寬，在希望增大校正膜23的內部應力的地方使遮蔽26的寬度變窄。在此，不分斷成多個區域而校正膜23的厚度均勻的圖7的（A）中的校正膜23的半徑方向的Duty比（占空比）是100%，相對於此，通過圖7的（C）的遮蔽26形成的校正膜23的Duty比為50%左右。因此，為了補償遮蔽26所致的Duty比降低所引起的非光學面側的內部應力的合力降低，最好增大校正膜23的厚度。在將校正膜23的Duty比設為50%的情況下，通過將校正膜23的膜厚設為200%，能夠補償校正膜23的內部應力的合力降低。　　[0031] 接下來，說明遮蔽26的寬度的設定。圖8是用於說明遮蔽26的配置的圖。圖8的（A）示出設定的遮蔽26的寬度的一個例子，圖8的（B）示出去掉遮蔽26之後的校正膜23的狀態，圖8的（C）示出校正膜23的內部應力分布。　　在希望提供如成為圖8的（C）所示的虛線的sin曲線那樣的內部應力分布的情況下，考慮圖8的（A）所示的遮蔽26寬度和與其相鄰的無遮蔽的地方的寬度之比來設定。根據期望的內部應力分布的空間頻率（即在具有空間上的週期的構造中的單位長度中包含的構造的重複的多少），設定任意的遮蔽26和相鄰的無遮蔽的部位的尺寸和即明暗寬度D以及它們的尺寸比值。即，在圖8的（C）的sin曲線中在橫軸上側的區域，在反射鏡21的變形中，反射膜22的影響大於校正膜23的影響，所以在反射膜22側呈現凸的變形。因此，為了使校正膜23的內部應力增加，在圖8的（A）的明暗寬度D中增大無遮蔽26的部位的寬度。由此，如圖8的（B）所示，校正膜23彼此的間隔變窄而成為較密地形成校正膜23的區域。相對於此，在圖8的（C）的sin曲線中在橫軸下側的區域，在反射鏡21的變形中，反射膜22的影響小於校正膜23的影響，所以在校正膜23側呈現凸的變形。因此，為了使校正膜23的內部應力減少，在圖8的（A）的明暗寬度D'中減小無遮蔽26的部位的寬度。由此，如圖8的（B）所示，校正膜23彼此的間隔變寬而成為較疏地形成校正膜23的區域。　　[0032] 但是，為了滿足高的空間頻率，最好考慮遮蔽26的配置誤差來進行設定。在遮蔽26的配置誤差為0.5mm時，可以將該配置誤差的十倍的5mm設為明暗寬度。通過降低遮蔽26的配置誤差，能夠使明暗寬度變窄，提高空間頻率。　　[0033] 接下來，簡單地說明本實施方式所涉及的光學元件2的製造方法。圖9是說明光學元件2的製造方法的流程圖。首先，確定圖1所示的光學面21a的成膜後的形狀（S11）。接下來，在考慮校正膜23的厚度的同時決定非光學面21b的校正膜23的分布（S12）。進而，使用遮蔽26在非光學面21b形成校正膜23（S13）。最後，檢查光學面21a的形狀（S14）。　　[0034] 通過在光學元件2的非光學面21b將校正膜23分開設置於多個區域，能夠有效地控制內部應力。例如，在有效面具有曲率並且在徑向上厚度不恒定的可變形狀光學元件等中，可能產生如高次的具有多個反曲點的複雜的變形，但通過將校正膜23的多個區域分成同心圓狀區域，能夠校正這樣的複雜的變形。因此，能夠在高的空間頻率下校正光學元件2的變形。另外，通過使同心圓狀區域的相鄰的膜區域23-n和非膜區域28的尺寸比值在光學元件2的半徑方向上變化，能夠在更高的空間頻率下校正光學元件2的變形。　　[0035] 進而，在使用膜厚分布控制板等通過蒸鍍、濺鍍形成校正膜的方法中，必須考慮成膜時的溫度、輸入能量等各種條件來詳細地預測檢討膜原料物質向光學元件的堆積厚度等狀態。因此，需要綿密的條件調整作業。相對於此，在本實施方式所涉及的方法中，並非控制成膜條件，而是使用遮蔽26形成膜區域23-n和非膜區域28，從而控制校正膜23的膜寬度的分布。因此，不需要複雜的條件調整而易於製造。　　[0036] 另外，通過將本實施方式所涉及的光學元件2應用於進行半導體製造中的將光罩（遮罩）上的圖案轉印到晶圓的光刻程序的曝光裝置，能夠抑制曝光時的溫度變化、濕度變化所引起的像差的劣化來改善成像特性。　　[0037] 　　[第二實施方式] 　　圖10是示出第二實施方式所涉及的光學元件2'的結構的概略剖面圖。在本實施方式中，對與第一實施方式所涉及的光學元件2相同的構成要素附加相同符號而省略說明。　　在本實施方式所涉及的光學元件2'中，在反射鏡21的非光學面21b，針對每個區域以期望的厚度設置有校正膜23。為了使厚度變化，例如使用多層膜。如圖10所示，在A區域中，校正膜23由校正膜23a、23b、23c這三層膜形成，在B區域中由校正膜23a、23b這兩層膜形成，在C區域中由校正膜23a的單層膜形成。這樣將校正膜23針對區域設為不同的膜厚，不僅在面內方向上而且在厚度方向上也能夠對反射鏡21提供更細緻的內部應力分布。　　[0038] 關於如圖10所示的根據區域而厚度不同的校正膜23，對反射鏡21的非光學面21b施加預定的圖案的遮蔽26，首先形成作為第一層的校正膜23a。接下來，施加與第一層不同的圖案的遮蔽26而形成第二層的校正膜23b，進而，施加與第一層以及第二層不同的圖案的遮蔽26而形成第三層的校正膜23c。　　[0039] 校正膜23a、23b、23c能夠分別用不同的材料成膜。但是，將校正膜23中的成膜面積最大的層即校正膜23a和反射膜22設為相同材料能夠抵消熱膨脹率所致的影響，所以是優選的。　　[0040] 如以上說明，在本實施方式所涉及的光學元件2'中，將校正膜23設為多層膜，根據區域變更多層的校正膜的累計厚度，從而能夠對反射鏡21提供更細緻的內部應力分布。　　[0041] 　　[第三實施方式] 　　圖11是示出第三實施方式所涉及的光學元件2''的結構的概略剖面圖。在本實施方式中，對與第一實施方式所涉及的光學元件2相同的構成要素附加相同符號而省略說明。　　在本實施方式所涉及的光學元件2''中，在反射鏡21的非光學面21b與校正膜23之間設置有用於改善非光學面21b和校正膜23的密接性的密接性提升膜33。　　[0042] 密接性提升膜33最好如圖11所示，設為不分割成多個區域而連續並且厚度均勻的膜。此外，密接性提升膜33只是具有改善密接性的作用的膜，並非如校正膜23那樣是以改變內部應力分布為目的成膜的膜。　　[0043] 圖12是示出第三實施方式的變形例所涉及的光學元件2'''的結構的概略剖面圖。在本實施方式所涉及的光學元件2'''中，以覆蓋校正膜23的整個面的方式設置有保護膜35。關於保護膜35。根據保護校正膜23以及反射鏡21的觀點，最好不將膜分割成多個區域，而是設置於校正膜23以及反射鏡21的表面整體。此外，保護膜35只是以保護校正膜23以及反射鏡21為目的成膜的膜，並非如校正膜23那樣是以改變內部應力分布為目的成膜的膜。　　[0044] 在設置密接性提升膜33、保護膜35的情況下的遮蔽26的設計中，首先求出反射鏡21、反射膜22、密接性提升膜33、保護膜35且沒有遮蔽26的均勻的校正膜23這樣的結構下的反射鏡21的變形。接下來，設計遮蔽26的分布以校正該變形。　　[0045] 　　[第四實施方式] 　　圖13是示出第四實施方式所涉及的曝光裝置100的結構的概略圖。　　曝光裝置100包括保持裝置110、照明光學系統120、投影光學系統130、能夠保持遮罩而移動的遮罩台140、以及能夠保持基板而移動的基板載台150。通過未圖示的控制部控制各部來執行基板的曝光處理。此外，在圖13中，在與作為鉛直方向的Z軸垂直的平面內，將Y軸取為曝光時的光罩以及基板的掃描方向，將X軸取為與Y軸正交的非掃描方向。另外，基板例如是硝材製的在表面塗敷有感光劑（抗蝕層）的被處理基板。進而，光罩例如是硝材製的形成有應轉印到基板的圖案（微細的凹凸圖案）的底版。　　[0046] 保持裝置110與圖2所示的可變形狀光學元件單元1同樣地構成，所以對相同構成要素附加相同符號而省略說明。保持裝置110包括基座3、支撐光學元件2的保持構材31、多個致動器4以及檢測部114。通過未圖示的控制部控制多個致動器4。包括光學元件2的中心的一部分（以下稱為中心部）經由保持構材31被固定到基座3。　　[0047] 多個致動器4配置於光學元件2與基座3之間，對光學元件2的背面的多個部位分別施加力。　　多個致動器4的各個例如包括不相互接觸的動子4a和定子4b，能夠對光學元件2的背面的各部位施加力。作為致動器4，例如能夠使用音圈馬達、線性馬達等。在作為致動器4使用音圈馬達的情況下，作為定子4b的線圈可固定於基座3，作為動子4a的磁鐵可固定於光學元件2的背面。另外，各致動器4通過對線圈供給電流而在線圈與磁鐵之間產生勞倫茲力，能夠對光學元件2的各部位施加力。在本實施方式中，在動子4a與定子4b之間有0.1mm左右的間隙，兩者未接觸。　　[0048] 檢測部114檢測光學元件2與基座3之間的距離。檢測部114可包括分別檢測光學元件2與基座3之間的距離的多個感測器（例如電容感測器）。通過這樣設置檢測部114，能夠根據檢測部114的檢測結果，進行多個致動器4的反饋控制，能夠使光學元件2的反射面按照目標形狀高精度地變形。　　[0049] 從照明光學系統120中包含的光源（未圖示）射出的光通過照明光學系統120中包含的狹縫（未圖示），例如能夠在遮罩上形成在X方向上較長的圓弧狀的照明區域。遮罩以及基板分別由遮罩台140以及基板載台150保持，配置於隔著投影光學系統130在光學上大致共軛的位置（投影光學系統130的物面以及像面的位置）。投影光學系統130具有預定的投影倍率，將形成於遮罩的圖案投影到基板。然後，使遮罩台140以及基板載台150在與投影光學系統130的物面平行的方向（例如Y方向）上，以與投影光學系統130的投影倍率對應的速度比相對地移動。由此，能夠進行在基板上掃描狹縫光的掃描曝光，將形成於遮罩的圖案轉印到基板。　　[0050] 投影光學系統130由保持平面鏡131以及133、凸面鏡132和光學元件2的鏡筒構成。從照明光學系統120射出並透射遮罩的曝光光通過平面鏡131而光路徑被折彎，入射到光學元件2的反射面的上部。在光學元件2的上部反射的曝光光被凸面鏡132反射，入射到光學元件2的反射面的下部。在光學元件2的下部反射的曝光光通過平面鏡133而光路徑被折彎，在基板上成像。在這樣構成的投影光學系統130中，凸面鏡132的表面為光學上的瞳。　　[0051] 　　（與物品的製造方法相關的實施方式）　　本實施方式所涉及的物品的製造方法例如適用於製造半導體裝置等微型裝置、具有微細構造的元件等物品。本實施方式的物品的製造方法包括：使用上述曝光裝置將潛像圖案形成于塗敷於基板的感光劑的程序（對基板進行曝光的程序）；以及使在上述程序中形成有潛像圖案的基板顯影的程序。進而，上述製造方法包括其它公知的程序（氧化、成膜、蒸鍍、摻雜、平坦化、蝕刻、抗蝕層剝離、切割、接合、封裝等）。本實施方式的物品的製造方法相比於以往的方法，在物品的性能、品質、生產性、生產成本的至少一方面有利。　　[0052] 以上，說明了本發明的優選的實施方式，但本發明不限定於這些實施方式，能夠在其要旨的範圍內進行各種變形以及變更。　　[0053] 例如，在上述各實施方式中，說明了基於光學膜的成膜的內部應力所引起的光學元件變形的校正，但還能夠用該校正應對光學元件與光學膜之間的熱膨脹率差所引起的光學元件變形。在光學元件與光學膜之間的熱膨脹率差所引起的光學元件變形的情況下，能夠通過將上述各實施方式中的變形與某個溫度差下的變形置換來應對。[0010] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the following embodiments, a mirror is described as an example of an optical element, but the effect is the same even if the mirror is replaced with another optical element (prism, lens) or the like. [0011] [First Embodiment] FIG. 1 is a schematic cross-sectional view illustrating a configuration of an optical element 2 according to a first embodiment of the present invention. The optical element 2 includes a mirror (ie, an optical element main body) 21 having an optical surface 21a for reflecting light and a non-optical surface 21b opposite to the optical surface 21a, and a correction film 23 as a first film provided in the non-optical The surface 21b is used to correct the distortion of the shape of the mirror 21. The correction film 23 is composed of a plurality of film regions 23-n as described later. In addition, the optical element 2 includes, on the optical surface 21a, a reflective film 22 as a second film which improves the optical function. As the mirror 21, for example, a variable shape optical element that changes the shape of the optical surface is used. [0012] FIG. 2 is a schematic cross-sectional view illustrating a configuration of a variable shape optical element unit 1 that deforms an optical element 2. In the optical element 2, a reflective film 22 is formed on an optical surface that is a surface of the mirror 21, and a correction film 23 is formed on a non-optical surface that is a back surface of the mirror 21. The optical element 2 is mounted on the base 3 via a holding member 31. In addition, a plurality of actuators 4 that deform and drive the mirror 21 are arranged on the back surface on the non-optical surface side of the optical element 2. By driving the actuator 4, the mirror 21 is deformed into a desired shape. [0013] In a photolithography process for transferring a pattern on a photomask (mask) to a wafer in semiconductor manufacturing, in order to image a very fine pattern on the wafer, the influence of aberrations of the optical system and the like becomes problem. In a semiconductor exposure apparatus that performs a photolithography process, imaging characteristics can be improved by using a variable shape optical element that deforms a lens or a mirror of an optical system. [0014] Generally, in optical elements that require high-precision shape accuracy, in order to cope with deformation caused by gravity, deformation from a lens barrel, and the like, it is designed to increase the thickness of the optical element as much as possible to improve rigidity. [0015] In contrast, in the case of a variable shape optical element, as shown in FIG. 2, a plurality of actuators 4 are generally arranged in a thin and easily deformable optical element 2 to deform the optical element 2. The shape of the optical element 2 is controlled. As described above, in the variable-shape optical element, the optical element 2 itself is deformed by the actuator 4, so that it is designed to reduce the thickness of the optical element 2 to reduce rigidity. The optical element 2 lowers the rigidity to reduce the thrust of the actuator 4, reduces wasteful heat generation of the actuator 4, and adverse effects such as deformation of other structures caused by the thrust of the actuator 4. [0016] As shown in FIG. 1, in a mirror 21 using a variable shape optical element, in order to improve optical characteristics, an optical film such as an anti-reflection film and a reflection film 22 is provided on the optical surface 21 a. The optical film is generally a multilayer film including a plurality of material layers, and has a thermal expansion coefficient different from that of the mirror 21. Therefore, due to the temperature change, the mirror 21 and the optical film are deformed like a bimetal. [0017] In addition, an optical thin film is formed on the reflecting mirror 21 by using a film forming method such as vapor deposition or sputtering, and internal stress is generated between the reflecting mirror 21 and the optical thin film to deform the optical element 2. [0018] A variable shape optical element used in a semiconductor exposure apparatus requires very high shape accuracy. Therefore, the distortion caused by the film formation of the optical film and the distortion caused by the temperature change of the optical film and the reflector 21 affect the optical performance. [0019] There is a method for reducing the internal stress by the film formation of the optical thin film for the deformation caused by the film formation. However, in order to reduce the internal stress, it is necessary to change the structure of an optically ideal multilayer optical film for reducing the internal stress, and the optical performance is deteriorated compared to an ideal optical film. [0020] There is a method for highly controlling the temperature of the deformation caused by the difference in thermal expansion coefficient between the mirror 21 and the optical film. However, in an exposure device, high-intensity exposure light is incident on the mirror 21, so it is difficult to manage temperature. [0021] As another means, as shown in FIG. 2, there is a method of driving the actuator 4 to correct the deformation of the mirror 21. However, since the correction of the deformation caused by the internal stress of the optical film is an offset correction, it is necessary to divide the restricted stroke and thrust of the actuator 4 to the correction of the deformation. [0022] The internal stress of an optical film is sensitive to temperature, humidity, etc., and changes over time. Therefore, even if it is possible to correct the deformation when the optical film is formed on the variable-shape optical element by the actuator 4, it is necessary to measure the shape of the variable-shape optical element for further deformation such as when the device is used later. The shape measurement of the variable shape optical element has various restrictions such as cost, and therefore, it is desirable to drive the actuator 4 open without performing shape measurement. However, in the open driving of the actuator 4, it is difficult to correct fluctuations in internal stress of the optical film and deformation due to thermal expansion. [0023] For example, as shown in FIG. 3, when a simple circular plate glass 6 is formed with an optical element having a thin film 25, the deformation caused by internal stress becomes a simple curvature change in which the circular plate is curved in a spherical shape. Therefore, the film stress deformation can be corrected by the configuration adjustment of the optical element, or can be driven and corrected by the actuator 4 shown in FIG. 2. [0024] On the other hand, as shown in FIG. 4, in the variable-shape optical element 24 having an active surface having a curvature and a constant thickness, when the thin film 25 having a uniform thickness is formed, the internal stress / thermal expansion of the thin film 25 is caused. Deformation of the high-order deformation is more than 2 times difficult to correct. Therefore, it is impossible to correct the adjustment of the arrangement of the optical elements, and the resolution is insufficient during the driving of the actuator 4 that deforms the variable shape optical element 24. [0025] In this embodiment, the above-mentioned problem is solved by controlling the distribution state of the correction film formed on the non-optical surface of the optical element. Specifically, for example, as shown in FIG. 1, the non-optical surface 21 b of the variable-shape mirror 21 is provided with a correction film 23 that is divided into a plurality of regions concentrically from the center of the mirror 21. That is, the correction film 23 is provided in the non-optical surface 21b in a plurality of film regions 23-1, 23-2, 23-3, ･････ 23-n, and ･････. Here, the interval d (j-k) between an arbitrary film region 23-j and the adjacent film region 23-k can be set to an arbitrary width in consideration of the internal stress distribution of the film. In addition, in the present embodiment, the interval d (xy) between the film region 23-x formed on the outer side of the film regions 23-j and 23-k and the film region 23-y adjacent thereto is formed to be larger than the interval d ( jk) is large, and the interval between the two is set to be different. [0026] In this embodiment, the distribution of internal stress is provided by adjusting the presence or absence of film formation. In the correction film 23, between the arbitrary film region 23-j and the film region 23-k adjacent thereto, there is a non-film region 28 in which no film exists. In order to form the non-film area 28 in the film formation of the correction film 23, a mask 26 as shown in FIG. 5 (A) is provided. When the correction film 23 is formed by the mask 26, a non-film region 28 as shown in FIG. 5 (B) can be formed. The masking 26 may be a general masking tape or a material for preventing film adhesion. However, there is a concern that chemical contamination may occur in the high-vacuum environment of the film-forming vacuum tank due to the shielding 26, so a substance with less chemical contamination is preferred. [0027] FIG. 6 is a schematic cross-sectional view showing a deformed state of the mirror 21 due to the internal stress of the film when the thickness of the non-optical surface correction film 23 is uniform over the entire surface. The thickness of the mirror 21 becomes thinner toward the outer periphery, so the bimetal effect caused by the internal stress of the mirror 21 and the film changes according to the thickness of the mirror 21. In addition, since the mirror 21 is a curved surface, the bimetal effect due to internal stress changes depending on the position in the radial direction. Therefore, even if a uniform film is formed on both the optical surface and the non-optical surface of the mirror 21, the non-linear deformation as shown in FIG. 6 remains. Therefore, in the correction film 23 having an influence on the deformation in FIG. 6, by adding a distribution to the internal stress to correct the deformation, it is possible to suppress the deformation of the mirror. [0028] FIG. 7 is a diagram for determining a shielding arrangement based on the deformation of the mirror 21 due to film stress. FIG. 7 (A) is a deformation state of the mirror 21 when the thickness of the correction film 23 is uniform, FIG. 7 (B) is a deformation amount of FIG. 7 (A), and FIG. 7 (C) is used for A layout diagram of a mask 26 for correcting the deformed internal stress distribution of FIG. 7 (B) is provided. [0029] The internal stress generated in the correction film 23 is constant regardless of the radius, but since the mirror 21 is curved and the thickness is uneven, the mirror 21 exhibits unevenness as shown in FIG. 7 (B). Deformation. In the range of K in FIG. 7 (B), the influence of the reflection film 22 is greater than the influence of the correction film 23, so the mirror 21 exhibits convex deformation on the reflection film side. On the other hand, in the range of L in (B) of FIG. 7, the influence of the correction film 23 is greater than that of the reflection film 22, so the mirror 21 exhibits convex deformation on the side of the correction film. That is, if the internal stress of the correction film 23 can be increased in the range of K, and the internal stress of the correction film 23 can be reduced in the range of L, the distortion of the mirror 21 shown in FIG. 7 (B) can be corrected. [0030] For each region of K and L, the internal stress of the correction film 23 is controlled by the mask 26 shown in FIG. 7 (C). The width of the shield 26 in the radial direction is widened where the internal stress of the correction film 23 is desired to be reduced, and the width of the shield 26 is narrowed where the internal stress of the correction film 23 is desired to be increased. Here, the Duty ratio (duty ratio) in the radial direction of the correction film 23 in FIG. 7A is 100% without being divided into a plurality of regions, and the thickness of the correction film 23 is uniform. The Duty ratio of the correction film 23 formed by the mask 26 of (C) of 7 is about 50%. Therefore, in order to compensate for the decrease in the resultant force of the non-optical surface side internal stress caused by the reduction of the Duty ratio caused by the masking 26, it is desirable to increase the thickness of the correction film 23. When the Duty ratio of the correction film 23 is set to 50%, by setting the film thickness of the correction film 23 to 200%, it is possible to compensate for a decrease in the resultant force of the internal stress of the correction film 23. [0031] Next, setting of the width of the mask 26 will be described. FIG. 8 is a diagram for explaining the arrangement of the mask 26. FIG. 8 (A) shows an example of the width of the mask 26, FIG. 8 (B) shows the state of the correction film 23 after the mask 26 is removed, and FIG. 8 (C) shows the inside of the correction film 23 Stress distribution. In a case where it is desired to provide an internal stress distribution such as a sin curve shown as a broken line in FIG. 8 (C), the width of the shield 26 shown in FIG. 8 (A) and the unshielded place adjacent thereto are considered. Set the width ratio. According to the desired spatial frequency of the internal stress distribution (that is, how much the structure is repeated in a unit length in a structure having a spatial period), the size of the arbitrary mask 26 and the adjacent unshielded part is set to be Light and dark width D and their size ratio. That is, in the area on the upper side of the horizontal axis in the sin curve of FIG. 8 (C), in the deformation of the mirror 21, the influence of the reflection film 22 is greater than the influence of the correction film 23, so convex deformation is present on the reflection film 22 side. . Therefore, in order to increase the internal stress of the correction film 23, the width of the unshielded portion 26 is increased in the light and dark width D of FIG. 8 (A). As a result, as shown in FIG. 8 (B), the interval between the correction films 23 is narrowed and a region in which the correction films 23 are densely formed is formed. On the other hand, in the region below the horizontal axis in the sin curve of FIG. 8 (C), the deformation of the reflecting mirror 21 has an influence of the reflection film 22 smaller than that of the correction film 23, so it appears on the side of the correction film 23 Convex deformation. Therefore, in order to reduce the internal stress of the correction film 23, the width of the unshielded portion 26 is reduced in the light-dark width D ′ of FIG. 8A. As a result, as shown in FIG. 8 (B), the interval between the correction films 23 is widened and a region where the correction films 23 are formed relatively thinly. [0032] However, in order to satisfy a high spatial frequency, it is better to set it in consideration of the placement error of the mask 26. When the placement error of the mask 26 is 0.5 mm, 5 mm, which is ten times the placement error, can be set as the light and shade width. By reducing the placement error of the mask 26, the light and dark width can be narrowed, and the spatial frequency can be increased. [0033] Next, a method of manufacturing the optical element 2 according to the present embodiment will be briefly described. FIG. 9 is a flowchart illustrating a method of manufacturing the optical element 2. First, the film-forming shape of the optical surface 21 a shown in FIG. 1 is determined (S11). Next, the distribution of the correction film 23 on the non-optical surface 21 b is determined while considering the thickness of the correction film 23 (S12). Further, a correction film 23 is formed on the non-optical surface 21 b using a mask 26 (S13). Finally, the shape of the optical surface 21a is checked (S14). [0034] The non-optical surface 21b of the optical element 2 is provided with the correction film 23 separately in a plurality of regions, so that internal stress can be effectively controlled. For example, in a variable shape optical element or the like having a curvature on the effective surface and a thickness that is not constant in the radial direction, a complicated deformation such as a high-order with a plurality of inflection points may occur, Dividing into concentric circles can correct such complicated deformation. Therefore, the distortion of the optical element 2 can be corrected at a high spatial frequency. In addition, by changing the size ratio of the adjacent film regions 23-n and non-film regions 28 of the concentric circular region in the radial direction of the optical element 2, the distortion of the optical element 2 can be corrected at a higher spatial frequency. [0035] Furthermore, in the method of forming a correction film by vapor deposition or sputtering using a film thickness distribution control board, etc., various conditions such as temperature and input energy during film formation must be considered to predict and review the film material substance to the optical element in detail. Stacking thickness and other conditions. Therefore, dense condition adjustment work is required. In contrast, in the method according to the present embodiment, instead of controlling the film formation conditions, the mask regions 26-n and the non-film regions 28 are formed using the mask 26 to control the distribution of the film width of the correction film 23. Therefore, it is easy to manufacture without requiring complicated condition adjustment. [0036] In addition, by applying the optical element 2 according to this embodiment to an exposure apparatus that performs a photolithography process for transferring a pattern on a photomask (mask) to a wafer in semiconductor manufacturing, it is possible to suppress exposure Deterioration of aberrations caused by temperature changes and humidity changes to improve imaging characteristics. [0037] [Second Embodiment] FIG. 10 is a schematic cross-sectional view illustrating a configuration of an optical element 2 'according to a second embodiment. In this embodiment, the same constituent elements as those of the optical element 2 according to the first embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted. In the optical element 2 ′ according to the present embodiment, the non-optical surface 21 b of the mirror 21 is provided with a correction film 23 with a desired thickness for each region. In order to change the thickness, a multilayer film is used, for example. As shown in FIG. 10, in the area A, the correction film 23 is formed by three layers of the correction films 23a, 23b, and 23c, in the area B, it is formed by two layers of the correction films 23a, 23b, and in the area C, the correction film A single-layer film of the film 23a is formed. Setting the correction film 23 to different regions with different film thicknesses in this way can provide the mirror 21 with a more detailed internal stress distribution not only in the in-plane direction but also in the thickness direction. [0038] Regarding the correction film 23 having different thicknesses according to regions as shown in FIG. 10, a non-optical surface 21b of the mirror 21 is masked 26 with a predetermined pattern, and a correction film 23a as a first layer is first formed. Next, a mask 26 of a pattern different from the first layer is applied to form a correction film 23b of the second layer, and a mask 26 of a pattern different from the first layer and the second layer is applied to form a correction film 23c of the third layer. . [0039] The correction films 23a, 23b, and 23c can be formed from different materials, respectively. However, it is preferable that the correction film 23a and the reflection film 22, which are the layers with the largest film formation area, of the correction film 23 be made of the same material to cancel the effect due to the thermal expansion rate. [0040] As described above, in the optical element 2 'according to this embodiment, the correction film 23 is a multilayer film, and the cumulative thickness of the multilayer correction film is changed according to the region, so that the mirror 21 can be provided with more detailed Internal stress distribution. [0041] [Third Embodiment] FIG. 11 is a schematic cross-sectional view illustrating a configuration of an optical element 2 "according to a third embodiment. In this embodiment, the same constituent elements as those of the optical element 2 according to the first embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted. In the optical element 2 ″ according to the present embodiment, an adhesion-improving film 33 is provided between the non-optical surface 21 b and the correction film 23 of the reflector 21 to improve the adhesion between the non-optical surface 21 b and the correction film 23. . [0042] As shown in FIG. 11, the adhesion-improving film 33 is preferably a film that is continuous and has a uniform thickness without being divided into a plurality of regions. The adhesiveness-improving film 33 is merely a film having an effect of improving adhesiveness, and is not a film formed for the purpose of changing the internal stress distribution like the correction film 23. [0043] FIG. 12 is a schematic cross-sectional view illustrating a configuration of an optical element 2 ′ ″ according to a modification of the third embodiment. In the optical element 2 ′ ″ according to the present embodiment, a protective film 35 is provided so as to cover the entire surface of the correction film 23. Concerning the protective film 35. From the viewpoint of protecting the correction film 23 and the reflection mirror 21, it is preferable not to divide the film into a plurality of regions, but to provide the entire surface of the correction film 23 and the reflection mirror 21. The protective film 35 is a film formed for the purpose of protecting the correction film 23 and the reflecting mirror 21, and is not a film formed for the purpose of changing the internal stress distribution like the correction film 23. [0044] In the design of the masking 26 when the adhesion-improving film 33 and the protective film 35 are provided, the uniformity of the mirror 21, the reflection film 22, the adhesion-improving film 33, and the protective film 35 without the masking 26 is first obtained. The distortion of the mirror 21 under the structure of the correction film 23. Next, the distribution of the mask 26 is designed to correct the deformation. [0045] [Fourth Embodiment] FIG. 13 is a schematic diagram illustrating a configuration of an exposure apparatus 100 according to a fourth embodiment. The exposure apparatus 100 includes a holding device 110, an illumination optical system 120, a projection optical system 130, a mask stage 140 that can move while holding a mask, and a substrate stage 150 that can move while holding a substrate. Each part is controlled by a control unit (not shown) to perform exposure processing of the substrate. In FIG. 13, in a plane perpendicular to the Z axis which is the vertical direction, the Y axis is taken as the scanning direction of the photomask and the substrate during exposure, and the X axis is taken as the non-scanning direction orthogonal to the Y axis. . In addition, the substrate is, for example, a substrate to be processed in which a photosensitizer (resist layer) is coated on the surface of the material. Furthermore, the photomask is, for example, a master plate made of a nitrate material and having a pattern (fine uneven pattern) to be transferred to a substrate. [0046] The holding device 110 is configured in the same manner as the variable shape optical element unit 1 shown in FIG. 2. Therefore, the same components are denoted by the same reference numerals, and descriptions thereof are omitted. The holding device 110 includes a base 3, a holding member 31 that supports the optical element 2, a plurality of actuators 4, and a detection unit 114. The plurality of actuators 4 are controlled by a control unit (not shown). A part (hereinafter referred to as a center portion) including the center of the optical element 2 is fixed to the base 3 via a holding member 31. [0047] The plurality of actuators 4 are disposed between the optical element 2 and the base 3, and apply a force to a plurality of portions on the rear surface of the optical element 2, respectively. Each of the plurality of actuators 4 includes, for example, a mover 4 a and a stator 4 b which are not in contact with each other, and can apply a force to various parts of the back surface of the optical element 2. As the actuator 4, for example, a voice coil motor, a linear motor, or the like can be used. When a voice coil motor is used as the actuator 4, the coil as the stator 4 b may be fixed to the base 3, and the magnet as the mover 4 a may be fixed to the back of the optical element 2. Each actuator 4 generates a Lorentz force between the coil and the magnet by supplying a current to the coil, and can apply a force to each part of the optical element 2. In this embodiment, there is a gap of about 0.1 mm between the mover 4a and the stator 4b, and the two are not in contact. [0048] The detection section 114 detects a distance between the optical element 2 and the base 3. The detection section 114 may include a plurality of sensors (for example, capacitive sensors) that respectively detect the distance between the optical element 2 and the base 3. By providing the detection unit 114 in this way, it is possible to perform feedback control of the plurality of actuators 4 based on the detection result of the detection unit 114, and it is possible to deform the reflection surface of the optical element 2 with high accuracy according to the target shape. [0049] Light emitted from a light source (not shown) included in the illumination optical system 120 can pass through a slit (not shown) included in the illumination optical system 120, and can be formed on the mask, for example, long in the X direction. Arc-shaped illuminated area. The mask and the substrate are held by the mask stage 140 and the substrate stage 150, respectively, and are disposed at positions that are approximately conjugated optically (positions of the object surface and image plane of the projection optical system 130) across the projection optical system 130. The projection optical system 130 has a predetermined projection magnification and projects a pattern formed on the mask onto a substrate. Then, the mask stage 140 and the substrate stage 150 are relatively moved in a direction (for example, the Y direction) parallel to the object plane of the projection optical system 130 at a speed ratio corresponding to the projection magnification of the projection optical system 130. Thereby, the scanning exposure which scans the slit light on a board | substrate can be performed, and the pattern formed in the mask can be transferred to a board | substrate. [0050] The projection optical system 130 includes a lens barrel that holds the flat mirrors 131 and 133, the convex mirror 132, and the optical element 2. The exposure light emitted from the illumination optical system 120 and transmitted through the mask passes through the plane mirror 131, the light path is bent, and is incident on the upper portion of the reflection surface of the optical element 2. The exposure light reflected on the upper portion of the optical element 2 is reflected by the convex mirror 132 and is incident on the lower portion of the reflecting surface of the optical element 2. The exposure light reflected at the lower part of the optical element 2 passes through the plane mirror 133, the light path is bent, and an image is formed on the substrate. In the projection optical system 130 configured as described above, the surface of the convex mirror 132 is an optical pupil. [0051] (Embodiment Related to Method for Manufacturing Article) The method for manufacturing an article according to this embodiment is suitable for manufacturing, for example, a microdevice such as a semiconductor device, a component having a fine structure, and the like. The method of manufacturing an article according to this embodiment includes a process of forming a latent image pattern on a substrate-coated photosensitizer (a process of exposing a substrate) using the exposure device, and forming a latent image pattern in the process. Process for substrate development. Furthermore, the above-mentioned manufacturing method includes other known procedures (oxidation, film formation, vapor deposition, doping, planarization, etching, resist peeling, dicing, bonding, packaging, etc.). The manufacturing method of the article of this embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of an article compared with the conventional method. [0052] The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist thereof. [0053] For example, in the above embodiments, the correction of the deformation of the optical element due to the internal stress of the film formation of the optical film has been described. However, the correction of the thermal expansion difference between the optical element and the optical film can also be used for this correction. Deformation of the optical element caused. When the optical element is deformed due to a difference in thermal expansion coefficient between the optical element and the optical film, it can be dealt with by replacing the deformation in each of the embodiments with a deformation at a certain temperature difference.

[0054][0054]

1‧‧‧可變形狀光學元件單元；1‧‧‧ variable shape optical element unit;

2‧‧‧光學元件2‧‧‧ Optical Elements

3‧‧‧基座3‧‧‧ base

4‧‧‧致動器4‧‧‧Actuator

6‧‧‧圓板玻璃6‧‧‧ round glass

21‧‧‧反射鏡21‧‧‧Mirror

21a‧‧‧光學面21a‧‧‧Optical surface

21b‧‧‧非光學面21b‧‧‧non-optical surface

22‧‧‧反射膜22‧‧‧Reflective film

23‧‧‧校正膜23‧‧‧correction film

23-n‧‧‧膜區域23-n‧‧‧ membrane area

24‧‧‧可變形狀光學元件24‧‧‧ Variable Shape Optical Element

25‧‧‧薄膜25‧‧‧ film

26‧‧‧遮蔽26‧‧‧ shelter

28‧‧‧非膜區域28‧‧‧ non-membrane area

31‧‧‧保持構材31‧‧‧ keep the material

33‧‧‧密接性提升膜33‧‧‧ Adhesiveness Enhancement Film

35‧‧‧保護膜35‧‧‧ protective film

[0009] 　　圖1是示出第一實施方式所涉及的光學元件的結構的概略剖面圖。　　圖2是示出可變形狀光學元件單元的結構的概略剖面圖。　　圖3是示出圓板玻璃中的薄膜所致的變形狀態的示意圖。　　圖4是示出曲面且在厚度中有分布的可變形狀光學元件中的薄膜所致的變形的示意圖。　　圖5是示出用於生成校正膜的區域的遮蔽（masking）的配置的剖面圖。　　圖6是示出使非光學面的校正膜的厚度在整個面均勻的情況下的、膜的內部應力所致的反射鏡的變形狀態的概略剖面圖。　　圖7是用於根據膜應力所致的反射鏡的變形求出遮蔽的配置的圖。　　圖8是用於說明遮蔽的配置的圖。　　圖9是說明光學元件的製造方法的流程圖。　　圖10是示出第二實施方式所涉及的光學元件的結構的概略剖面圖。　　圖11是示出第三實施方式所涉及的光學元件的結構的概略剖面圖。　　圖12是示出第三實施方式的變形例所涉及的光學元件的結構的概略剖面圖。　　圖13是示出第四實施方式所涉及的曝光裝置的結構的概略圖。[0009] FIG. 1 is a schematic cross-sectional view illustrating a configuration of an optical element according to a first embodiment. FIG. 2 is a schematic cross-sectional view showing a configuration of a variable shape optical element unit. FIG. 3 is a schematic diagram showing a deformed state caused by a thin film in a circular plate glass. FIG. 4 is a schematic view showing deformation caused by a thin film in a variable shape optical element having a curved surface and a distribution in thickness. FIG. 5 is a cross-sectional view showing an arrangement of masking of a region for generating a correction film. FIG. 6 is a schematic cross-sectional view showing a deformed state of a mirror due to an internal stress of a film when the thickness of a non-optical surface correction film is uniform over the entire surface. FIG. 7 is a diagram for determining a shielding arrangement based on a deformation of a mirror due to a film stress. FIG. 8 is a diagram for explaining the arrangement of masking. FIG. 9 is a flowchart illustrating a method of manufacturing an optical element. 10 is a schematic cross-sectional view showing a configuration of an optical element according to a second embodiment. FIG. 11 is a schematic cross-sectional view illustrating a configuration of an optical element according to a third embodiment. FIG. 12 is a schematic cross-sectional view showing a configuration of an optical element according to a modification of the third embodiment. 13 is a schematic diagram showing a configuration of an exposure apparatus according to a fourth embodiment.

Claims

一種光學元件，具備：光學元件主體，具有設置有反射膜的光學面及與前述光學面相反側的非光學面；以及多個校正膜，設置於前述非光學面側，用於校正前述光學元件主體的形狀，前述多個校正膜在前述非光學面側被分開設置於彼此不同的多個區域，前述多個校正膜之中，第1間隔與第2間隔不同，該第1間隔係設於前述光學元件主體的外側且彼此鄰接的第1校正膜與第2校正膜的間隔，該第2間隔係設於比前述第1校正膜及前述第2校正膜靠內側且彼此鄰接的第3校正膜與第4校正膜的間隔。An optical element comprising: an optical element body having an optical surface provided with a reflective film and a non-optical surface opposite to the optical surface; and a plurality of correction films provided on the non-optical surface side for correcting the optical element In the shape of the main body, the plurality of correction films are separately provided on a plurality of regions different from each other on the non-optical surface side. Among the plurality of correction films, a first interval is different from a second interval, and the first interval is provided at The distance between the first correction film and the second correction film which are adjacent to each other on the outer side of the optical element main body, and the second interval is provided in the third correction which is located inward and adjacent to the first correction film and the second correction film. The distance between the film and the fourth correction film.

根據第1項的光學元件，其中，前述光學元件主體具備具有曲率且徑向的厚度不恒定的圓板的形狀，前述多個校正膜被從前述光學元件主體的中心按照同心圓狀分開設置於多個區域。The optical element according to item 1, wherein the optical element main body has a shape of a circular plate having a curvature and a constant thickness in a radial direction, and the plurality of correction films are provided in a concentric circle form from a center of the optical element main body. Multiple areas.

根據第1項的光學元件，其中，前述第1間隔比前述第2間隔大。The optical element according to item 1, wherein the first interval is larger than the second interval.

根據第1項的光學元件，其中，前述校正膜是多層膜。The optical element according to item 1, wherein the correction film is a multilayer film.

根據第4項的光學元件，其中，前述多層膜中的至少一個膜和前述反射膜是相同材料。The optical element according to item 4, wherein at least one of the aforementioned multilayer films and the aforementioned reflective film are the same material.

根據第1項的光學元件，其中，在前述光學元件主體的前述非光學面與前述校正膜之間設置有使前述非光學面和前述校正膜密接的膜。The optical element according to item 1, wherein a film for closely contacting the non-optical surface and the correction film is provided between the non-optical surface of the optical element body and the correction film.

一種曝光裝置，對基板進行曝光，包括投影光學系統，該投影光學系統包括：如第1至6項中任一項的光學元件；以及保持裝置，保持前述光學元件，前述曝光裝置經由前述投影光學系統對前述基板進行曝光。An exposure device for exposing a substrate includes a projection optical system including: the optical element according to any one of items 1 to 6; and a holding device holding the optical element, the exposure device passing through the projection optical The system exposes the aforementioned substrate.

一種物品的製造方法，具有以下程序：使用如第7項的曝光裝置對基板進行曝光；以及使在前述程序中曝光後的前述基板顯影。A method of manufacturing an article, comprising the steps of: exposing a substrate using an exposure apparatus according to item 7; and developing the substrate after the exposure in the procedure.