200917324 九、發明說明 【發明所屬之技術領域】 本發明是關於具備二氧化矽玻璃所成的放電容器’在 介設有形成該放電容器的二氧化矽玻璃的狀態下設有一對 電極所成，而在上述放電容器的內部發生準分子放電的準 分子燈。 【先前技術】 近年來，開發了例如藉由將波長200nm以下的真空紫 外光照射在金屬、玻璃及其他材料所成的被處理體，而藉 由該真空紫外光及由此所生成的臭氧的作用來處理被處理 體的技術，例如除去附著於被處理體的表面的有機污染物 質的洗淨處理技術或在被處理體的表面形成氧化膜的氧化 膜形成處理技術，而被實用化。 作爲照射真空紫外光的裝置，使用例如藉由準分子放 電形成準分子分子，而將利用從該準分子分子所放射的光 例如波長1 70nm附近的準分子燈具備作爲光源者，在此種 準分子燈中，爲了更有效率地放射更高強度的紫外線，實 施很多嘗試。 具體上，例如參照第6圖加以說明，記載著具備透射 紫外線的二氧化矽玻璃所成的放電容器5 1，而在該放電容 器5 1的內側與外側分別設有電極5 5、5 6所成的準分子燈 5〇中’在曝露於放電容器51的放電空間s的表面，形成 紫外線反射膜2 G，而作爲紫外線反射膜’僅由二氧化砂粒 200917324 子所成者，及僅由氧化鋁粒子所成者被例示於實施例（參 照專利文獻1 )。 在該準分子燈50中，在放電容器51的一部分，形成 有藉由未形成有紫外線反射膜20進行出射在放電空間S 內所發生的紫外線的光出射部5 8。 依照此種構成的準分子燈5 0，在被曝露於放電容器 5 1的放電空間S的表面，藉由設有紫外線反射膜，在設 有紫外線反射膜的領域中，發生在放電空間S內的紫外線 藉由紫外線反射膜被反射之故，因而不會入射至二氧化矽 玻璃’而在構成光出射部5 8的領域中，紫外線透射二氧 化矽玻璃被放射至外部之故，因而基本上，有效地可利用 在放電空間S內所發生的紫外線，而且可將構成光出射部 5 8以外的領域的二氧化矽玻璃的紫外線失真所致的損壞抑 制成較小，而可防止發生裂痕的情形。 專利文獻：日本專利第3 5 8 0 2 3 3號公報 【發明內容】 近幾年來，對於照射具備準分子燈的真空紫外光的裝 置的一種願望’爲要求更提昇處理率，作爲對於此種願望 的措施’可能有有效地使用從準分子燈所放射的更短波長 的光。該理由是波長短的光是能量較大之故，因而即使爲 少光量也可得到大的作用。 然而，習知的準分子燈的紫外線反射膜，是未具有如 波長1 5 0 nm附近的光的反射特性者之故，因而無法達成上 -5- 200917324 述願望乃爲實際情況。 因此，本案發明人等，即使爲些微量，也形成可反射 波長1 5 Onm的附近的光的紫外線反射膜，若有效率地可利 用該波長的光，也認爲可提昇將具備如該準分子燈的真光 紫外光予以照射的裝置的處理能力者，而逐完成了本發明 〇 本發明的目的，是提供有效率地可利用波長150nm附 近的短波長的光，而可構成作爲具有高處理能力者的準分 子燈，作爲目的。 本發明的準分子燈，屬於具備備有放電空間的二氧化 矽玻璃所構成的放電容器，在介設有形成該放電容器的二 氧化矽玻璃的狀態下設有一對電極，而且在放電空間內封 入有氙氣體所成，而在上述放電容器的放電空間內發生準 分子放電的準分子燈，其特徵爲： 在曝露於上述放電容器的放電空間的表面，形成有二 氧化矽粒子與氧化鋁粒子所形成的紫外線反射膜，含有於 該紫外線反射膜的矽及鋁以外的雜質金屬的濃度爲 700wtppm 以下。 依照本發明的準分子燈，藉由紫外線反射膜爲二氧化 矽粒子與氧化鋁粒子所形成，而矽及鋁以外的雜質金屬的 濃度爲700wtppm以下，可構成作爲不僅波長170nm附近 的光，甚至針對於比波長150nm附近更短波長的光也具有 反射該紫外線反射膜的功能者，而且形成放電容器的二氧 化矽玻璃爲具有透射波長140~150nm以上的光的特性之故 -6- 200917324 ，因而有效率地可出射利用準分子放電所發生的真空紫外 光，因此有效地可利用包含能量大的1 5 Onm附近的短波長 的光的真空紫外光，可構成作爲具有高處理能力者。 【實施方式】 第1圖是表示本發明的準分子燈的一例的構成的槪略 的說明用斷面圖’ （a)是表示沿著放電容器的長度方向 的斷面的橫斷面圖，（b)是表示（a)的A-A線斷面圖。 該準分子燈1 0是具備兩端被氣密地封閉而形成有放 電空間S的斷面矩形狀的中空長狀的放電容器1 1，而在 該放電容器11的內部，作爲放電用氣體，被封入有氣氣 體。在此，氙氣體是作成壓力爲如成爲 10〜60kPa ( 100〜600mbar)的範圍內的封入量。 放電容器11是由良好地透射真空紫外光的二氧化矽 玻璃，例如合成石英玻璃所成，具有作爲介質的功能。 在放電容器Η的長邊面的外表面，配置一對格子狀 電極，亦即，相對向配置著作爲高電壓饋電電極的功能的 一方電極15及功能作爲接地電極的另一方電極16朝長度 方向延伸，藉由此，作成在一對電極15、16間介設有作 爲介質的功能的放電容器1 1的狀態。 此種電極是例如藉由將金屬所成的電極材料糊膏塗佈 於放電容器11，或是藉由照片印刷可形成。 在該準分子燈1 〇中，當點燈電力被供應於一方的電 極1 5，則經由功能作爲介質的放電容器1 1的壁而在兩電 200917324 極15、16間生成放電，藉由此’形成有準分子分子’而 且從該準分子分子產生真空紫外光所放射的準分子放電’ 而藉由氙氣體的封入壓力爲作爲如 10〜60kPa ( 100~600mbar)的範圍內，放射著壓波長150nm附近具有 峰値的真空紫外光。 具體上，例如，如第2圖（1 )所示地，在氙氣體的 封入壓力爲50mbar時，則發光著在波長150nm附近具有 峰値P1的從波長145nm前後一直到波長190nm爲止的波 長域的光。又，如第2圖（2)所示地，在氙氣體的封入 壓力爲lOOmbar時，則發光著在波長150nm附近及波長 17 0nm附近具有峰値P2、P3的從波長145nm前後一直到 波長190nm爲止的波長域的光。又，第2圖（3)是氣氣 體的封入壓力爲680mbar時的準分子放電發光光譜。 如上述地，放電容器11爲藉由二氧化矽玻璃，尤其 是藉由雜質少的合成石英玻璃所構成，藉此，合成石英玻 璃玻璃是具有透射波長1 40〜1 5 Onm以上的波長的光的特性 之故，因而在氙氣體的封入壓力例如作爲10〜60kPa ( 100〜600mbar)的範圍內的上述構成的準分子燈10中，波 長140〜150nm以上，而放射著在波長150nm附近及波長 1 7 0 n m附近具有峰値的真空紫外光。 然而，在上述準分子燈10中，爲了有效率地利用藉 由準分子放電所發生的真空紫外光，例如被曝露在放電容 器1 1的放電空間S的表面，設有二氧化矽粒子與氧化鋁 粒子所形成的紫外線反射膜2 0。 -8- 200917324 紫外線反射膜20是例如對應於放電容器1 1的長邊面 的功碎作爲局電壓饋電電極的一方電極15的內表面領域 與連續於該領域的短邊面的內表面領域的一部分全面所形 成’而在對應於放電容器11的長邊面的功能作爲接地電 極的另一方電極1 6的內表面領域，藉由未形成有紫外線 反射膜20來構成光出射部（孔徑部）1 8。 紫外線反射膜20的膜厚是例如1〇~ 100 μιη較佳。 紫外線反射膜2 0是至少曝露於放電空間S的表面層 部分’亦即，接受隨著準分子放電所產生的電漿的影響使 得二氧化矽粒子熔融而發生粒界消失的例如在深度約2 μιη的範圍內，氧化鋁粒子與二氧化矽粒子混在所成者， 例如藉由二氧化矽粒子與氧化鋁粒子的堆積體可構成。 紫外線反射膜20是二氧化矽粒子及氧化鋁粒子本體 具有備有高折射率的真空紫外光透射性者之故，因而到達 至二氧化矽粒子或氧化鋁粒子的真空紫外光的一部分在粒 子表面被反射，同時其他的一部分折射而被入射至粒子內 部’又被入射於粒子內部的大部分光被透射（一部分被吸 收）’而再出射之際被折射的具有重複產生此種反射與折 射的「擴散反射」的功能。 又’紫外線反射膜2 0是由二氧化矽粒子與氧化鋁粒 子所構成，亦即藉由陶瓷所構成，具有不會發生不純氣體 ’又耐於放電的特性。 構成紫外線反射膜2 0的二氧化矽粒子，是例如可使 用將二氧化矽坡璃粉末狀地作成細粒子者等。 -9 - 200917324 二氧化矽粒子是如下地被定義的粒子徑爲例如 0.0 1〜2 0 μπι的範圍內者，中心粒徑（數平均粒子徑的峰値 )爲如〇·1~1〇 μιη者較佳，更佳爲0.3〜3 μηι者。 又，具有中心粒徑的二氧化矽粒子的比率爲5 0%以上 較佳。 構成紫外線反射膜20的氧化鋁粒子是如下地被定義 的粒子徑爲例如0.1 ~ 1 0 n m的範圍內者，中心粒徑（數平 均粒子徑的峰値）爲如0.1〜3 μιη者較佳，更佳爲0.3〜1 μηι 者 〇 又，具有中心粒徑的氧化鋁粒子的比率爲5 0%以上較 佳。 構成紫外線反射膜2 0的二氧化矽粒子及氧化鋁粒子 的「粒子徑」，是指將紫外線反射膜2 0對於其表面朝垂 直方向切剖時的切剖面的厚度方向的大約中間位置作爲觀 察範圍’藉由掃描型電子顯微鏡（S ΕΜ )取得擴大投影像 ，而以一定方向的兩條平行線隔著該擴大投影像的任意粒 子時的該平行線的間隔的弗雷特（F e r e t )直徑。 如第3 ( a )圖所示地’具體上，在以單獨存在著大約 球狀的粒子A及具有粉碎粒子形狀的粒子b等的粒子時， 將以朝著一定方向（例如紫外線反射膜2 0的厚度方向延 伸的兩條平行線隔著該粒子時的該平行線的間隔作爲粒徑 DA、DB。 又’針對於具有出發材料的粒子經熔融所接合的形狀 的粒子C，如第3 ( b )圖所示地，針對於被判別爲出發材 -10- 200917324 料的粒子C 1、C2的部分的各該球狀部分，測定以朝一定 方向〔例如紫外線反射膜2 0的厚度方向〕延伸的2條平 行線相夾時的該平行線的間隔，將此作爲該粒子的粒徑 DC1、DC2。 構成紫外線反射膜2 0的二氧化矽粒子及氧化鋁粒子 「中心粒子」，是指將針對於如上述所得到的各粒子的粒 子徑的最大値與最小値的粒子徑的範圍，例如以〇 . 1 μηι 的範圍分成複數區分，例如區分成約1 5區分，屬於各個 區分的粒子個數（度數）成爲最大的區分的中心値。 二氧化矽粒子及氧化鋁粒子是藉由具有與真空紫外光 的波長相同程度的上述範圍的粒子徑者，有效率地可擴散 反射真空紫外光。 然而，在上述準分子燈1 0，藉由紫外線反射膜20含 有氧化鋁粒子者，除了成爲二氧化矽粒子的主成分的矽及 成爲氧化鋁粒子的主成分的鋁以外的雜質金屬會成爲不可 避免地被混入的情形，例如，在二氧化矽粒子的純度及氧 化鋁粒子的純度之關係，藉由調整構成紫外線反射膜20 的二氧化矽粒子與氧化鋁粒子的混合比成爲適當範圍，使 得含有於紫外線反射膜20的雜質金屬的濃度（合計）被 規制在7 〇 0 w t p p m以下的狀態。 含有於紫外線反射膜20的氧化鋁粒子的比率’是二 氧化矽粒子與氧化鋁粒子的合計的例如1 wt%以上較佳， 更佳爲5 w t %以上，而最佳爲1 〇 w t %。 又，二氧化矽粒子與氧化鋁粒子的合計的7〇%wt以下 -11 - 200917324 較佳，更佳爲4 0 w t %以下。 藉由紫外線反射膜20以上述混合比來構成著二氧化 砂粒子與氧化銘粒子，即使長時間被點燈時，也確實地可 抑制二氧化矽粒子被熔融而把紫外線反射膜2〇的反射率 會大幅度地降低的情形’而且不會大幅度地降低氧化鋁粒 子混入所致的紫外線反射膜20對於放電容器U的黏合性 (接著性）之故，因而確實地可防止紫外線反射膜2〇被 剝落的情形’而且可將雜質金屬的濃度成爲所定値以下的 狀態。 此種紫外線反射膜2 0是例如稱爲「流下法」的方法 ’就可形成。亦即，在具有組合水與PEO樹脂（聚乙烯氧 化物）的黏性的溶劑，混合二氧化矽粒子及氧化鋁粒子來 調配分散液，藉由將該分散液流進放電容器形成材料內， 附著於放電容器形成材料的內表面的所定領域之後，利用 乾燥、燒成，把水與PEO樹脂予以蒸發，就可形成紫外線 反射膜2 0。在此，燒成溫度是例如作爲5 0 0〜1 1 0 0 °C。 形成紫外線反射膜20之際所用的二氧化矽粒子及氧 化鋁粒子的製造，是都可利用固相法、液相法、氣相法的 任何方法，惟在此些中，由確實地可得到亞微細粒，微米 尺寸的粒子，以氣相法，尤其是化學蒸鍍法（CVD )較佳 〇 具體上，例如二氧化矽粒子是藉由將氯化矽與氧在 900〜1〇〇〇 °C予以反應，而氧化鋁粒子是藉由將原料的氯 化鋁與氧在1 000〜1 200°c予以加熱反應，就可加以合成， -12- 200917324 而粒子徑是藉由控制原料濃度，反應場的壓 就可調整。 一般，在準分子燈，眾知隨著準分子放 漿，惟在如上述的構成的準分子燈中’電漿 地入射於紫外線反射膜而施以作用之故’因 膜的溫度會局部地急激地被上昇，若紫外線 二氧化矽粒子所成者，則藉由電槳的熱，使 子被熔融而會消失粒界有無法擴散反射真空 低反射率的情形。 然而，紫外線反射膜2 0爲由二氧化矽 粒子所構成，藉由此，依照上述構成的準分 上，即使被曝露在依電漿所致的熱時，其有 子還高融點的氧化鋁粒子是也不會熔融之故 彼此間結合著互相地鄰接的二氧化矽粒子與 防止而被維持著粒界之故，因而即使長時間 有效率地可擴散反射真空紫外光而實質上可 射率。又，氧化鋁粒子是具有比二氧化矽粒 之故，因而與僅由二氧化矽粒子所形成的紫 比較’可得到高反射率。 而且，依照上述構成的準分子燈1 0，藉 有於紫外線反射膜2 0的二氧化矽粒子的主 爲氧化鋁粒子的主成分的鋁以外的雜質3 700wtppm以下，如下述的實驗例的結果所 外線反射膜20構成作爲不僅波長1 7〇nm附 力，反應溫度 電，就發生電 成爲大約直角 而紫外線反射 反射膜僅爲如 得二氧化矽粒 紫外光而有降 粒子與氧化鋁 子燈10，基本 比二氧化矽粒 ，因而以粒子 氧化鋁粒子被 被點燈時，也 維持初期的反 子還高折射率 外線反射膜相 由除了成爲含 成分的矽及成 屬的濃度爲 示地，可將紫 近的光，甚至 -13- 200917324 針對於波長1 5〇nm附近的光也具有反射特性者之故，因而 藉由形成放電容器的二氧化矽玻璃爲具有透射波長 14 0〜15 Onm以上的光的特性之故，因而有效率地可利用在 藉由準分子放電所發生的波長150nm附近及波長170nm 附近具有真空紫外光，成爲具有高處理能力者。 又，藉由在被曝露在產生準分子發光的放電空間S的 放電容器1 1的內表面形成有紫外線反射膜20，可將放電 空間S內的真空紫外線隨著入射於光出射部1 8以下的領 域的二氧化矽玻璃的紫外線失真所致的損傷予以減小，而 可防止發生裂痕。 以下，將爲了確認本發明的效果所進行的實施例加以 說明。 (實驗例1 :紫外線反射膜的反射特性） 準備純度爲9 9.9 9 %，9 9 _ 9 %及純度9 9.8 %的3種類的 二氧化矽粒子，與純度爲9 9.9 9 %、9 9.9 %及純度9 9.8 %的 3種類的氧化鋁粒子，將二氧化矽粒子與氧化鋁粒子適當 地變更組合’而且將二氧化矽粒子與氧化鋁粒子的混合比 (二氧化矽粒子：氧化鋁粒子）在2〇 : 80〜80 : 20的範圍 內適當地變更’而在合成石英玻璃所成的厚度lmm的基 材上’藉由流下法來形成紫外線反射膜，俾製作複數種類 的試驗片。在此’形成紫外線反射膜之際的燒成溫度是 ll〇〇°C，而膜厚是 30 μηι。 二氧化矽粒子是任何純度者，粒子徑範圍爲〇 . 3〜1 . 0 -14- 200917324 μ m，而中心粒子徑爲0.3 μ m，具有中心粒子徑的粒子比 率爲5 0 %者。 氧化鋁粒子是任何純度者，粒子徑範圍爲0.2〜0.7 μιη ，而中心粒子徑爲〇.4 μιη，具有中心粒子徑的粒子比率爲 5 0 % 者。 針對於各個試驗片的紫外線反射膜，測定含有於該紫 外線反射膜的矽及鋁以外的雜質金屬的濃度，而且測定波 長150nm的光的反射光強度及波長170nm的光的反射光 強度。將結果表示於第4圖。 〈雜質金屬濃度的測定方法〉 以純水進行洗淨試驗片之後，乾燥後進行試驗片的秤 量，使用特弗隆（Teflon )(登記商標）膠帶來遮蔽試驗 片的基材所露出的部分（未形成有紫外線反射膜的二氧化 矽玻璃部分），在該狀態下，浸漬在氟酸中而藉由施以加 熱來進行蝕刻處理，在以目視無法確認試驗片的紫外線反 射膜的時候取出試驗片，進行該試驗片的秤量，而藉由比 較進行蝕刻理前後的試驗片的秤量値來算出紫外線反射膜 的質量。 之後，將含有著藉由蝕刻以氟酸溶解的二氧化矽粒子 (成分）’與未被溶解而粒狀地殘留的氧化銘粒子，及雜 質金屬成分的氟酸液，加以加溫，首先，將與氟酸反應的 二氧化矽成分蒸發作爲SiF4 ’將藉由此成爲殘渣所留下的 氧化鋁成分與雜質成分，放進由85 %磷酸6.5ml，97 %硫 -15- 200917324 酸3.5 5ml所成的混酸中，藉由微波加熱爐進行溶解氧化 銘成分與雜質成分之後’添加純水而稀釋成爲合計30ml 的溶液。 然後’利用ICP發光分光分析裝置，依據稀釋溶液中 的雜質金屬的濃度來測定雜質金屬的質量，對應於雜質金 屬封於作爲測疋封象的紫外線反射膜的質量〇 . 5 g的質量 比’而得到含有於紫外線反射膜中的殘留雜質金屬的濃度 〇 作爲一例子，例如由純度9 9 · 9 9 %的二氧化矽粒子 30wt% ’與純度99.8%的氧化鋁70wt%所構成的紫外線反 射膜的雜質金屬成分及此些的濃度是如下述表1所示。又 ’雜質金屬是指含有鈹.鎂的鹼土類金屬，或是屬於過渡 金屬的元素者。 表1 雜質金屬的濃度〔wtppm〕 Fe Μη Mg Cr Ti Ca Ni Mo σ 口 T 666.0 5.6 1.4 0.0 20.3 0.7 0.0 0.5 694.5 〈反射光強度的測定方法〉 針對於紫外線反射膜的波長1 5 Onm的光的反射光強度 ’及波長170nm的光的反射光強度之測定，是使用 ACTON RESEARCH所製的「VM-5 20」。該裝置的測定部 ，是由如第5圖所示的直入射型光學系統所構成，放射著 從波長1 20nm以下的光一直到可視光爲止的連續光的重氫 200917324 燈60被使用作爲光源。在該裝置，爲將從重氫燈60所放 射的光，一旦適當地接觸於凹面光柵6 1之後，通過開縫 62而照射在試驗片TS，俾將藉由該試驗片TS所反射的反 射光（散射光），一面以0。〜180。的範圍內調整受光面的 角度，一面利用將受光於攝影用插入式配件6 5所得到的 測定値，而得到針對於特定波長的光的反射光強度。 針對於反射光強度的測定方法具體地加以說明’首先 ，針對於未具有紫外線反射膜的基材（合成石英玻璃）， 取得散射光的波長150nm的光及波長170nm的光的各該 反射光強度（基準値），之後，設置形成有紫外線反射膜 的試驗片，測定散射光的波長150nm的光及波長170nm 的光的各該反射光強度，藉由以基準値（未具有紫外線反 射膜的基材的測定値）來除算由此所得到的各該測定値， 而得到波長150nm的光的反射光強度及波長170nm的光 的反射光強度。 由表示於第4圖的結果可明瞭，波長150nm的反射光 強度與波長1 70 nm的光的反射光強度，及雜質金屬的濃度 是線形的關係，而可知更近似於直線。 又，150nm的光的反射光強度成爲0.000時的雜質金 屬的濃度是700wtppm，而170nm的光的反射光強度成爲 0.000時的雜質金屬的濃度是1181wtppm，因此，藉由將 含有於紫外線反射膜的雜質金屬的濃度，控制成至少成爲 700wtppm以下的狀態，確認了不僅170nm的光，還可成 爲確實地具有反射150nm的光的功能者。 -17- 200917324 因此，在實際的準分子燈中，藉由紫外線反射膜是雜 質金屬的濃度被規制在700wtppm以下者，成爲有效率地 可利用包含藉由準分子放電所發生的波長150nm的光的真 空紫外光者。 (實驗例2 ) 由純度爲99.9%的二氧化矽粒子，及純度爲99.8%的 氧化鋁粒子所形成，而將以氧化鋁粒子的含有比率變更爲 Owt%、10wt%、33wt%、50wt%的紫外線反射膜，在膜厚 3 0 μιη下藉由流下法形成在平板狀合成石英玻璃所成的厚 1 mm的基材上’俾製作4種類的試驗片。 又，針對於各試驗片，將紫外線反射膜加熱成1 OOOt： 時’及加熱成1 3 0 0 °C時的各該情形的波長1 7 0 nm的先的 反射光強度，使用ACTON RESEARCH所製的「VM-502」 而利用上述方法進行測定，若紫外線反射膜的氧化鋁粒子 的含有比率爲Owt%時，亦即，在未含有氧化鋁粒子時， 對於被加熱成相當於形成紫外線反射膜之際的燒成溫度的 溫度1 〇〇〇 °C時的反射光強度，被加熱成相當於電槳作用於 紫外線反射膜時的加熱溫度的溫度1 3 0 0 t的情形，確認了 會大幅度降低反射光強度，由此可假設在實際的準分子燈 ’在電漿接觸到紫外線反射膜的部位，會有反射光強度局 部性地降低’使得準分子燈的照度分布成爲不均勻，而當 準分子燈長時間被點燈，則電漿會碰到紫外線反射膜全體 ，而會降低反射率者。 -18- 200917324 一方面，在添加1 〇 w t %氧化銘粒子者，即使被加熱成 130(TC時，反射光強度比未添加氧化鋁粒子時還高，而確 認了也可將依熱的紫外線反射膜的反射率的降低程度抑制 在70%左右。又，隨著氧化鋁粒子的含有比率增加，則可 將依熱的紫外線反射膜的反射率的降低程度抑制成較小， 例如在添加50wt%氧化鋁粒子者，被加熱成l〇〇〇°C時的反 射光強度，與被加熱成1 300 °C時的反射光強度成爲一致， 而被確認可抑制降低依熱的紫外線反射膜的反射率。 因此，在實際的準分子燈中，藉由紫外線反射膜添加 有氧化鋁粒子1 Owt%以上者，即使準分子燈長時間被點燈 而使紫外線反射膜曝露於電漿之熱時，也可抑制二氧化矽 粒子熔融所致的反射率的降低。 又，在該實驗例2中所製作的試驗片的含有氧化鋁粒 子的紫外線反射膜，雜質金屬的濃度也爲700wtppm以下 者。 以上，針對於本發明的實施形態加以說明，惟本發明 是並不被限定於上述實施形態者，而可加入各種變更。 本發明是並不被限定於上述構成的準分子燈者’也可 適用於如第6圖所示的雙重管構造的準分子燈，或是如第 7圖所示的所謂「四方型」的準分子燈。 如第6圖所示的準分子燈5 0，是具有二氧化矽玻璃管 所形成的圓筒狀外側管5 2，及在該外側管5 2內沿著其管 軸所配置的具有比該外側管5 2的內徑還小的外徑的例如 二氧化矽玻璃管所形成的圓筒狀內側管53，外側管52與 -19- 200917324 內側管5 3在兩端部被熔融接合而在外側管5 2與內側管5 3 之間具備形成有環狀放電空間S所成的雙重管構造的放電 容器5 1，例如金屬所形成的一方的電極（高電壓供應電極 )5 5密接設於內側管5 3的內周面，而且例如由金屬網等 的導電性材料所形成的另一方的電極56密接設於外側管 5 2的外周面，而在放電空間S內，例如塡充有藉由氙氣 體等準分子放電形成準分子分子的放電用氣體所構成。 在此種構成的準分子燈5 0中，例如在放電容器5 1的 內側管5 3的內表面的所有全周設有上述紫外線反射膜2 0 ，而且在外側管5 2的內表面，除了形成光出射部5 8的一 部分的領域以外設有上述紫外線反射膜20。 表示於第7圖的準分子燈40是例如具備合成二氧化 矽玻璃所成的斷面長方形的放電容器4 1所成，而金屬所 成的一對外側電極4 5，4 5配設於放電容器4 1的互相相對 向的外表面成爲朝放電容器4 1的管軸方向延伸，而且放 電用氣體的例如氙氣體被塡充於放電容器41內。在第7 圖中，符號42是排氣管’而符號43是如鋇所形成的吸氣 劑。 在此種構成的準分子燈4 0中，對應於放電容器4 1的 內表面的各個外側電極4 5、4 5的領域及連續於此些領域 一方的內面領域的所有領域’設有上述紫外線反射膜20， 而藉由未設有紫外線反射膜2 0以形成光出射部4 4。 【圖式簡單說明】 -20- 200917324 第1圖是表示本發明的準分子燈的一例子的構成槪略 的說明用斷面圖’ （a)是表示沿著放電容器的長度方向 的斷面的斷面圖，（b)是表示（a)的A-A線斷面圖。 第2圖是表示封入有氙氣體的準分子燈的準分子放電 發光光譜的圖表。 第3圖是表示用於說明二氧化矽粒子及氧化鋁粒子的 粒子徑的定義的說明圖。 第4圖是表示針對於在實驗例所製作的紫外線反射膜 的特定波長的光的反射光強度，及含有於紫外線反射膜的 雜質金屬的濃度之關係的圖表。 第5圖是表示用於說明針對於在實驗例所製作的紫外 線反射膜的使用於測定反射光強度的裝置的測定原理的圖 表。 第6圖是表示本發明的準分子燈的另一例子的構成槪 略的說明用斷面圖，（a)是表示沿著放電容器的長度方 向的斷面的橫斷面圖，（b)是表示（a)的A-A線斷面圖 〇 第7圖是表示本發明的準分子燈的其他例子的構成槪 略的說明用斷面圖，（a)是表示沿著放電容器的長度方 向的斷面的斷面圖，（b )是表示依垂直於（a )的紙面的 平面的斷面的斷面圖。 【主要元件符號說明】 1 0 :準分子燈 -21 - 200917324 1 1 :放電容器 15: —方的電極（高電壓供應電極） 1 6 :另一方的電極（接地電極） 1 8 :光出射部（孔徑部） 20 :紫外線反射膜 3 〇 :鋁製容器 3 1 :支撐台 3 5 :紫外線照度計 40 :準分子燈 4 1 :放電容器 42 :排氣管 4 3 :吸氣劑 44 :光出射部 45 :外側電極 5 0 :準分子燈 5 1 :放電容器 5 2 :外側管 5 3 :內側管 55: —方的電極（高電壓供應電極） 5 6 :另一方的電極 5 8 :光出射部 6 0 :重氫燈 61 :凹型光柵 62 :開縫 -22- 200917324 65 :攝影插入式配件 T S :試驗片 S :放電空間 -23[Technical Field] The present invention relates to a discharge vessel having a ceria glass formed by providing a pair of electrodes in a state in which ceria glass forming the discharge vessel is interposed. An excimer lamp in which excimer discharge occurs inside the discharge vessel. [Prior Art] In recent years, for example, a vacuum ultraviolet light having a wavelength of 200 nm or less is irradiated onto a metal, glass, and other materials, and the vacuum ultraviolet light and ozone generated thereby are developed. A technique for processing a target object, for example, a cleaning treatment technique for removing an organic contaminant attached to a surface of a target object or an oxide film formation treatment technique for forming an oxide film on the surface of the object to be processed, is put to practical use. As a device for irradiating vacuum ultraviolet light, for example, excimer molecules are formed by excimer discharge, and light emitted from the excimer molecule, for example, an excimer lamp having a wavelength of around 170 nm is provided as a light source. In molecular lamps, many attempts have been made to emit higher-intensity ultraviolet rays more efficiently. Specifically, for example, as described with reference to Fig. 6, a discharge vessel 5 1 made of erbium silicate glass that transmits ultraviolet ray is described, and electrodes 5 5 and 56 are provided on the inner side and the outer side of the discharge vessel 5 1 , respectively. The resulting excimer lamp 5' is formed on the surface of the discharge space s exposed to the discharge vessel 51 to form the ultraviolet-ray reflective film 2G, and as the ultraviolet-ray reflective film 'only composed of the oxidized sand particles 200917324, and only by oxidation The aluminum particles are exemplified in the examples (see Patent Document 1). In the excimer lamp 50, a light emitting portion 58 that emits ultraviolet rays generated in the discharge space S without forming the ultraviolet reflecting film 20 is formed in a part of the discharge vessel 51. The excimer lamp 50 having such a configuration is formed in the discharge space S in the field in which the ultraviolet ray reflection film is provided on the surface of the discharge space S exposed to the discharge vessel 51 by the ultraviolet ray reflection film. Since the ultraviolet ray is reflected by the ultraviolet ray reflection film, it is not incident on the erbium sulphide glass, and in the field constituting the light exit portion 580, the ultraviolet ray transmitting cerium oxide glass is radiated to the outside, and thus basically The ultraviolet rays generated in the discharge space S can be effectively utilized, and the damage caused by the ultraviolet ray distortion of the cerium oxide glass constituting the field other than the light exit portion 58 can be suppressed to be small, and cracking can be prevented. situation. Patent Document: Japanese Patent No. 3 5 0 0 2 3 3 SUMMARY OF THE INVENTION In recent years, a desire for irradiating a device having vacuum ultraviolet light having an excimer lamp has been required to increase the processing rate as a The measure of desire 'may have the effect of using shorter wavelengths of light emitted from the excimer lamp. This reason is that light having a short wavelength has a large energy, and therefore a large effect can be obtained even with a small amount of light. However, the ultraviolet reflecting film of the conventional excimer lamp is a reflection characteristic of light having a wavelength of around 150 nm, and thus the above-described wish is not achieved. Therefore, the inventors of the present invention form an ultraviolet ray reflection film that can reflect light in the vicinity of a wavelength of 15 Onm even in a small amount, and it is considered that the light can be improved if it is efficiently used. The present invention has been accomplished by the object of the present invention to provide efficient use of short-wavelength light having a wavelength of around 150 nm, and can be constructed as a high processing. The excimer lamp of the capable person is for the purpose. The excimer lamp of the present invention belongs to a discharge vessel comprising a ceria glass provided with a discharge space, and is provided with a pair of electrodes in a state in which ceria glass forming the discharge vessel is interposed, and is in a discharge space. An excimer lamp in which an excimer discharge is generated in a discharge space of the discharge vessel, and a cerium oxide particle and an alumina are formed on a surface of a discharge space exposed to the discharge vessel. The ultraviolet ray reflection film formed by the particles contains the concentration of the impurity metal other than ruthenium and aluminum contained in the ultraviolet ray reflection film at 700 wtppm or less. According to the excimer lamp of the present invention, the ultraviolet ray reflection film is formed of cerium oxide particles and alumina particles, and the concentration of the impurity metal other than cerium and aluminum is 700 wtppm or less, and can be formed not only as light having a wavelength of around 170 nm, but even The light having a shorter wavelength than the wavelength near 150 nm also has a function of reflecting the ultraviolet reflective film, and the ceria glass forming the discharge vessel has a characteristic of transmitting light having a wavelength of 140 to 150 nm or more -6-200917324, Therefore, the vacuum ultraviolet light generated by the excimer discharge can be efficiently emitted, so that vacuum ultraviolet light containing short-wavelength light near the energy of 15 5 Onm can be effectively utilized, and it can be constructed as a high processing capability. [Embodiment] FIG. 1 is a cross-sectional view showing a schematic configuration of an example of an excimer lamp according to the present invention, and FIG. 1(a) is a cross-sectional view showing a cross section along the longitudinal direction of the discharge vessel. (b) is a cross-sectional view taken along line AA of (a). The excimer lamp 10 is a hollow discharge vessel 1 having a rectangular cross section in which a discharge space S is formed to be closed at both ends, and a discharge gas is used as a discharge gas inside the discharge vessel 11. It is enclosed in gas. Here, the helium gas is a sealing amount in a range of 10 to 60 kPa (100 to 600 mbar). The discharge vessel 11 is made of cerium oxide glass which is well transmitted with vacuum ultraviolet light, such as synthetic quartz glass, and has a function as a medium. On the outer surface of the long side surface of the discharge vessel ,, a pair of lattice electrodes are disposed, that is, one electrode 15 that functions as a high voltage feed electrode and a other electrode 16 that functions as a ground electrode face each other The direction is extended, whereby the discharge vessel 1 1 having a function as a medium is interposed between the pair of electrodes 15 and 16. Such an electrode can be formed, for example, by applying a paste of an electrode material made of a metal to the discharge vessel 11, or by photo printing. In the excimer lamp 1 ,, when the lighting power is supplied to one of the electrodes 15 , a discharge is generated between the poles 15 and 16 of the two electric powers 20091624 via the wall of the discharge vessel 1 1 functioning as a medium. 'Forming an excimer molecule' and generating an excimer discharge emitted by vacuum ultraviolet light from the excimer molecule', and by using a sealing pressure of the helium gas as a range of, for example, 10 to 60 kPa (100 to 600 mbar), radiation pressure Vacuum ultraviolet light having a peak 附近 near a wavelength of 150 nm. Specifically, for example, as shown in Fig. 2 (1), when the sealing pressure of the helium gas is 50 mbar, the wavelength range from the wavelength of 145 nm to the wavelength of 190 nm having the peak 値P1 at a wavelength of around 150 nm is emitted. Light. Further, as shown in Fig. 2 (2), when the sealing pressure of the helium gas is 100 mbar, the light is emitted from the vicinity of the wavelength of 150 nm and the peaks of P2 and P3 around the wavelength of 145 nm to the wavelength of 190 nm. Light in the wavelength range up to. Further, Fig. 2 (3) shows an excimer discharge luminescence spectrum when the sealing pressure of the gas is 680 mbar. As described above, the discharge vessel 11 is made of cerium oxide glass, in particular, synthetic quartz glass having a small amount of impurities, whereby the synthetic quartz glass glass is light having a wavelength of a wavelength of 1 40 to 15 nm or more. Therefore, in the excimer lamp 10 having the above-described configuration in the range of 10 to 60 kPa (100 to 600 mbar), the sealing pressure of the helium gas is, for example, a wavelength of 140 to 150 nm or more, and a wavelength of about 150 nm and a wavelength. Vacuum ultraviolet light with peaks near 1 70 nm. However, in the above excimer lamp 10, in order to efficiently utilize vacuum ultraviolet light generated by excimer discharge, for example, exposed on the surface of the discharge space S of the discharge vessel 11, a cerium oxide particle and oxidation are provided. The ultraviolet ray reflection film 20 formed of aluminum particles. -8- 200917324 The ultraviolet ray reflection film 20 is, for example, an inner surface field of one electrode 15 as a local voltage feeding electrode corresponding to the long side surface of the discharge vessel 1 1 and an inner surface field continuous with the short side surface of the field A part of the inner surface of the other electrode 16 which functions as a ground electrode in the function of the long side surface of the discharge vessel 11 is formed, and the light exit portion (the aperture portion) is formed by not forming the ultraviolet ray reflection film 20 ) 18. The film thickness of the ultraviolet ray reflection film 20 is preferably, for example, 1 〇 to 100 μηη. The ultraviolet ray reflection film 20 is at least a surface layer portion exposed to the discharge space S. That is, the cerium oxide particles are melted by the influence of the plasma generated by the excimer discharge, and the grain boundary disappears, for example, at a depth of about 2 In the range of μιη, alumina particles and ceria particles are mixed, for example, by a stack of ceria particles and alumina particles. The ultraviolet ray reflection film 20 is a ruthenium dioxide particle and an alumina particle body having a vacuum ultraviolet light transmittance having a high refractive index, so that a part of the vacuum ultraviolet light reaching the cerium oxide particle or the aluminum oxide particle is on the particle surface. Reflected, while other parts are refracted and incident on the inside of the particle, and most of the light incident on the inside of the particle is transmitted (partially absorbed) and refraction is refraction with repeated reflections and refractions. The function of "diffusion reflection". Further, the ultraviolet ray reflecting film 20 is composed of cerium oxide particles and alumina particles, that is, it is composed of ceramics, and has characteristics of not impure gas and resistance to discharge. The cerium oxide particles constituting the ultraviolet ray reflecting film 20 are, for example, those in which cerium oxide slag is powdered into fine particles. -9 - 200917324 The cerium oxide particles are defined as follows. The particle diameter is, for example, in the range of 0.01 to 2 0 μπι, and the central particle diameter (peak of the number average particle diameter) is 〇·1~1〇μηη. Preferably, it is preferably 0.3 to 3 μηι. Further, the ratio of the cerium oxide particles having a central particle diameter is preferably 50% or more. The alumina particles constituting the ultraviolet ray reflection film 20 have a particle diameter as defined below, for example, in the range of 0.1 to 10 nm, and the center particle diameter (peak 数 of the number average particle diameter) is preferably 0.1 to 3 μm. More preferably, it is 0.3 to 1 μηι, and the ratio of the alumina particles having a central particle diameter is preferably 50% or more. The "particle diameter" of the cerium oxide particles and the alumina particles constituting the ultraviolet ray reflection film 20 is an approximate position in the thickness direction of the cross section when the ultraviolet ray reflection film 20 is cut in the vertical direction. The range 'Feret is obtained by scanning electron microscopy (S ΕΜ ), and the interval between the parallel lines when the arbitrary particles of the projected image are interposed by two parallel lines in a certain direction. diameter. As shown in Fig. 3 (a), in particular, when particles such as approximately spherical particles A and particles b having pulverized particles are present alone, they are oriented in a certain direction (for example, ultraviolet reflecting film 2). The interval between the parallel lines when the two parallel lines extending in the thickness direction of 0 are interposed between the particles is referred to as the particle diameters DA and DB. Further, the particles C having a shape in which the particles having the starting material are joined by melting are as described in the third (b) As shown in the figure, each of the spherical portions of the portion of the particles C1 and C2 determined to be the starting material of the starting material-10-200917324 is measured in a certain direction (for example, the thickness direction of the ultraviolet reflecting film 20). The interval between the parallel lines when the two parallel lines are stretched is the particle diameters DC1 and DC2 of the particles. The cerium oxide particles constituting the ultraviolet ray reflection film 20 and the "central particles" of the alumina particles are The range of the particle diameters of the maximum 値 and the minimum 粒子 of the particle diameters of the respective particles obtained as described above, for example, the range of μ. 1 μηι is divided into plural numbers, for example, divided into about 15 divisions, and the particles belonging to each division are classified. One (degree) becomes the center of the largest division. The cerium oxide particles and the alumina particles are efficiently diffused and reflected by the ultraviolet ray by having a particle diameter within the above range which is the same as the wavelength of the vacuum ultraviolet light. In the above-mentioned excimer lamp 10, the aluminum oxide particles are contained in the ultraviolet ray-reflecting film 20, and it is inevitable that an impurity other than aluminum which is a main component of the cerium oxide particles and aluminum which is a main component of the alumina particles is inevitable. In the case where the ground is mixed, for example, in the relationship between the purity of the cerium oxide particles and the purity of the alumina particles, the mixing ratio of the cerium oxide particles and the alumina particles constituting the ultraviolet ray reflecting film 20 is adjusted to an appropriate range to contain The concentration (total) of the impurity metal in the ultraviolet ray reflection film 20 is adjusted to be in a state of 7 〇 0 wtppm or less. The ratio 'the ratio of the alumina particles contained in the ultraviolet ray reflection film 20' is, for example, the total of the cerium oxide particles and the alumina particles. More preferably 1 wt% or more, more preferably 5 wt% or more, and most preferably 1 〇 wt %. Further, cerium oxide particles and oxygen The total amount of the aluminum oxide particles is preferably 7 〇% wt or less -11 - 200917324, more preferably 40% by weight or less. The ultraviolet ray reflection film 20 constitutes the silica sand particles and the oxidized crystal particles by the above mixing ratio, even if When it is lighted for a long time, it is possible to surely suppress the melting of the cerium oxide particles and greatly reduce the reflectance of the ultraviolet ray reflection film 2 ', and it does not significantly reduce the mixing of the alumina particles. Since the ultraviolet ray reflection film 20 has adhesiveness (adhesiveness) to the discharge vessel U, it is possible to surely prevent the ultraviolet ray reflection film 2 from being peeled off, and the concentration of the impurity metal can be set to a state below the predetermined value. The reflection film 20 is formed, for example, as a method of "flow down method". That is, in a viscous solvent having a combination of water and a PEO resin (polyethylene oxide), the cerium oxide particles and the alumina particles are mixed to prepare a dispersion, and the dispersion is introduced into the discharge vessel forming material, After adhering to a predetermined area of the inner surface of the discharge vessel forming material, the water and the PEO resin are evaporated by drying and baking to form the ultraviolet reflecting film 20. Here, the firing temperature is, for example, 5 0 0 to 1 1 0 0 °C. The production of the cerium oxide particles and the alumina particles used for forming the ultraviolet ray reflection film 20 can be any method using a solid phase method, a liquid phase method, or a gas phase method, but in these cases, it is surely available. Submicron particles, micron-sized particles, preferably by gas phase method, especially chemical vapor deposition (CVD), for example, cerium oxide particles are obtained by using cerium chloride and oxygen at 900 to 1 Torr. The reaction is carried out at °C, and the alumina particles are synthesized by heating the aluminum chloride of the raw material with oxygen at 1 000 to 1 200 ° C, -12-200917324 and the particle diameter is controlled by the concentration of the raw material. The pressure of the reaction field can be adjusted. In general, in an excimer lamp, it is known that the excimer is discharged, but in the excimer lamp having the above configuration, the plasma is incident on the ultraviolet reflecting film and acts. If it is formed by the ultraviolet cerium oxide particles, the heat of the electric blade causes the particles to be melted, and the grain boundary disappears, and the vacuum low reflectance cannot be diffused and reflected. However, the ultraviolet ray reflection film 20 is composed of cerium oxide particles, whereby, according to the above-mentioned composition, even if it is exposed to heat by plasma, it has a high melting point oxidation. Since the aluminum particles are not melted, the cerium oxide particles adjacent to each other are bonded to each other and are prevented from being grain boundary, so that the vacuum ultraviolet light can be diffused and reflected efficiently for a long period of time. rate. Further, since the alumina particles have a specific bismuth dioxide particle, the high reflectance can be obtained by comparing with the violet formed only by the cerium oxide particles. In addition, the excimer lamp 10 of the above-described configuration is based on the result of the following experimental example: the impurity of the main component of the alumina particle of the ultraviolet ray oxidization film 20 is not more than 700 wtppm of aluminum. The outer-line reflection film 20 is configured to have not only a wavelength of 17 〇 nm, but also a reaction temperature, and the electric power is about a right angle, and the ultraviolet-reflective reflection film is only a sulphur dioxide ultraviolet light and has a falling particle and an alumina sub-lamp. 10, basically, compared with cerium oxide particles, when the particles of alumina particles are lighted, the initial phase of the high-refractive-index outer-reflecting film phase is maintained by the concentration of the bismuth and the genus which are contained components. The purple near light, even -13-200917324, has a reflection characteristic for light near the wavelength of 15 〇nm, and thus the erbium silicate glass forming the discharge vessel has a transmission wavelength of 14 0 to 15 Since the characteristics of light above Onm are utilized, it is possible to efficiently use vacuum ultraviolet light in the vicinity of a wavelength of 150 nm generated by excimer discharge and a wavelength of 170 nm. Processing ability. Further, by forming the ultraviolet ray reflection film 20 on the inner surface of the discharge vessel 1 exposed to the discharge space S where the excimer light is emitted, the vacuum ultraviolet ray in the discharge space S can be incident on the light emission portion 18 or less. The damage caused by the ultraviolet distortion of the field of cerium oxide glass is reduced, and cracking is prevented. Hereinafter, examples for confirming the effects of the present invention will be described. (Experimental Example 1: Reflection characteristics of ultraviolet reflective film) Three types of cerium oxide particles having a purity of 99.99%, 9 9 -9 %, and a purity of 9.9.8 % were prepared, and the purity was 99.99%, 99.9%. And three types of alumina particles having a purity of 9.9.8 %, the cerium oxide particles and the alumina particles are appropriately combined and combined, and the mixing ratio of the cerium oxide particles and the alumina particles (cerium oxide particles: alumina particles) In the range of 2 〇: 80 to 80: 20, the 'ultraviolet-reflecting film was formed by a down-flow method on the substrate having a thickness of 1 mm made of synthetic quartz glass, and a plurality of test pieces were produced. Here, the firing temperature at the time of forming the ultraviolet reflecting film is ll 〇〇 ° C, and the film thickness is 30 μη. The cerium oxide particles are of any purity, and the particle diameter ranges from 〜 3 to 1 . 0 -14 to 200917324 μ m, and the central particle diameter is 0.3 μ m, and the particle ratio of the central particle diameter is 50%. The alumina particles are of any purity, the particle diameter ranges from 0.2 to 0.7 μm, and the central particle diameter is 〇.4 μιη, and the ratio of the particles having the central particle diameter is 50%. With respect to the ultraviolet ray reflection film of each test piece, the concentration of the impurity metal other than yttrium and aluminum contained in the ultraviolet ray reflection film was measured, and the intensity of reflected light of light having a wavelength of 150 nm and the intensity of reflected light of light having a wavelength of 170 nm were measured. The results are shown in Fig. 4. <Method for Measuring Impurity Metal Concentration> After the test piece was washed with pure water, the test piece was weighed after drying, and the exposed portion of the substrate of the test piece was shielded with a Teflon (registered trademark) tape ( The cerium oxide glass portion in which the ultraviolet ray-reflecting film is not formed is immersed in the fluoric acid in this state, and is subjected to an etching treatment by heating, and the removal test is performed when the ultraviolet ray-reflecting film of the test piece cannot be visually confirmed. The sheet was weighed, and the mass of the ultraviolet ray reflection film was calculated by comparing the enthalpy of the test piece before and after the etching. After that, the cerium oxide particles (components) which are dissolved by the fluoric acid by etching are oxidized, and the oxidized acid particles which are left in the form of particles which are not dissolved and are granulated, and the fluoric acid liquid of the impurity metal component are heated. First, Evaporation of the cerium oxide component reacted with hydrofluoric acid as SiF4' will result in the alumina component and impurity component left by the residue, and is put into 6.5 ml of 85% phosphoric acid, 97% sulfur-15-200917324 acid 3.5 5 ml. In the mixed acid obtained, the solution was dissolved in a microwave heating furnace to dissolve the oxidized component and the impurity component, and then diluted with pure water to obtain a total of 30 ml of the solution. Then, using ICP emission spectroscopic analyzer, the mass of the impurity metal is determined according to the concentration of the impurity metal in the diluted solution, corresponding to the mass of the impurity metal seal on the ultraviolet reflective film as a test seal. 质量 5 g mass ratio ' The concentration 〇 of the residual impurity metal contained in the ultraviolet ray reflection film is, for example, an ultraviolet ray reflection composed of 30 wt% of cerium oxide particles having a purity of 99.9% and 70 wt% of alumina having a purity of 99.8%. The impurity metal components of the film and the concentrations thereof are as shown in Table 1 below. Further, the impurity metal refers to an alkaline earth metal containing strontium magnesium or an element belonging to a transition metal. Table 1 Concentration of impurity metal [wtppm] Fe Μη Mg Cr Ti Ca Ni Mo σ Port T 666.0 5.6 1.4 0.0 20.3 0.7 0.0 0.5 694.5 <Method for measuring reflected light intensity> For the wavelength of light-reflecting film of 15 5 Onm The measurement of the intensity of the reflected light and the intensity of the reflected light of the light having a wavelength of 170 nm was performed using "VM-5 20" manufactured by ACTON RESEARCH. The measuring unit of the apparatus is composed of a direct incidence optical system as shown in Fig. 5, and a heavy hydrogen which emits continuous light from light having a wavelength of 1 20 nm or less until visible light is used. The light 60 is used as a light source. In this apparatus, the light radiated from the deuterium lamp 60, once properly contacted with the concave grating 61, is irradiated to the test piece TS by the slit 62, and the reflected light reflected by the test piece TS is irradiated. (scattered light), with 0 on one side. ~180. In the range of adjusting the angle of the light receiving surface, the intensity of the reflected light for the light of a specific wavelength is obtained by using the measurement 得到 obtained by receiving the photolithographic accessory 65. The measurement method of the intensity of the reflected light is specifically described. First, for the substrate (synthetic quartz glass) having no ultraviolet ray reflection film, the intensity of the reflected light of the light having a wavelength of 150 nm and the light having a wavelength of 170 nm is obtained. (reference 値), after that, a test piece in which an ultraviolet ray reflection film was formed was provided, and the intensity of each of the reflected light of the light having a wavelength of 150 nm and the light having a wavelength of 170 nm of the scattered light was measured by the reference 値 (the base having no ultraviolet ray reflection film) The measurement of the material was carried out to obtain the measured light intensity of the light having a wavelength of 150 nm and the intensity of the reflected light of the light having a wavelength of 170 nm. As is clear from the results shown in Fig. 4, the intensity of the reflected light having a wavelength of 150 nm and the intensity of the reflected light of the light having a wavelength of 170 nm and the concentration of the impurity metal are linear, and it is more similar to a straight line. In addition, the concentration of the impurity metal when the reflected light intensity of the light of 150 nm is 0.000 is 700 wtppm, and the concentration of the impurity metal when the reflected light intensity of the light of 170 nm becomes 0.000 is 1181 wtppm, and therefore, it is contained in the ultraviolet reflective film. The concentration of the impurity metal was controlled to be at least 700 wtppm or less, and it was confirmed that not only light of 170 nm but also light having a reflection of 150 nm was confirmed. -17- 200917324 Therefore, in an actual excimer lamp, when the concentration of the impurity metal is regulated to be 700 wtppm or less by the ultraviolet ray reflection film, it is possible to efficiently use light having a wavelength of 150 nm which occurs by excimer discharge. Vacuum ultraviolet light. (Experimental Example 2) The cerium oxide particles having a purity of 99.9% and alumina particles having a purity of 99.8% were formed, and the content ratio of the alumina particles was changed to Owt%, 10% by weight, 33% by weight, and 50% by weight. Four types of test pieces were produced by forming a UV-reflective film on a substrate having a thickness of 1 mm formed by flat-shaped synthetic quartz glass by a down-flow method at a film thickness of 30 μm. Further, for each test piece, the ultraviolet light-reflecting film was heated to a temperature of 1 070 nm at the time of heating to 1 10000 t: and the intensity of the first reflected light at a wavelength of 170 nm in each case when heated to 1,300 ° C, using ACTON RESEARCH The "VM-502" manufactured by the above method is measured, and when the content ratio of the alumina particles of the ultraviolet-ray reflective film is Owt%, that is, when the alumina particles are not contained, it is heated to form an ultraviolet-ray reflection. When the temperature of the firing temperature at the time of the film is 1 〇〇〇 °C, the intensity of the reflected light is heated to a temperature corresponding to the heating temperature at the time when the electric blade acts on the ultraviolet reflecting film, and the temperature is confirmed to be 1 3 0 0 t. The intensity of the reflected light is greatly reduced, and it can be assumed that in the actual excimer lamp 'the portion where the plasma contacts the ultraviolet reflecting film, the intensity of the reflected light is locally lowered', so that the illuminance distribution of the excimer lamp becomes uneven. When the excimer lamp is turned on for a long time, the plasma will hit the entire ultraviolet reflecting film, and the reflectance will be lowered. -18- 200917324 On the one hand, when adding 1 〇wt% of oxidized granules, even when heated to 130 (TC, the intensity of reflected light is higher than when no alumina particles are added, and it is confirmed that ultraviolet rays can be heated. The degree of reduction in the reflectance of the reflective film is suppressed to about 70%. Further, as the content ratio of the alumina particles is increased, the degree of reduction in the reflectance of the ultraviolet-ray-reflecting film according to heat can be suppressed to be small, for example, by adding 50 wt. In the case of the % alumina particles, the intensity of the reflected light when heated to 10 ° C is the same as the intensity of the reflected light when heated to 1 300 ° C, and it is confirmed that the ultraviolet reflective film which reduces the heat is suppressed. Therefore, in an actual excimer lamp, when the alumina particle is added by 10% by weight or more by the ultraviolet reflecting film, even if the excimer lamp is turned on for a long time, the ultraviolet reflecting film is exposed to the heat of the plasma. Further, the decrease in the reflectance due to the melting of the cerium oxide particles can be suppressed. Further, in the ultraviolet ray-reflecting film containing the alumina particles of the test piece prepared in Experimental Example 2, the concentration of the impurity metal is also 700 wtppm. The above is an embodiment of the present invention, but the present invention is not limited to the above embodiment, and various modifications can be added. The present invention is not limited to the excimer lamp of the above configuration. 'Also applicable to the excimer lamp of the double tube structure as shown in Fig. 6, or the so-called "quadruple type" excimer lamp as shown in Fig. 7. The excimer lamp 5 as shown in Fig. 6 0 is a cylindrical outer tube 52 formed of a ceria glass tube, and has a smaller inner diameter than the outer tube 52 in the outer tube 52 along its tube axis. The cylindrical inner tube 53 formed of, for example, a ceria glass tube, the outer tube 52 and the -19-200917324 inner tube 53 are fused at both ends and between the outer tube 52 and the inner tube 5 3 A discharge vessel 5 1 having a double tube structure formed by an annular discharge space S, for example, one electrode (high voltage supply electrode) 5 formed of a metal is closely attached to the inner peripheral surface of the inner tube 533, and for example The other electrode 56 formed of a conductive material such as a metal mesh is dense The discharge chamber S is connected to the outer peripheral surface of the outer tube 52, and is filled with a discharge gas for forming an excimer molecule by excimer discharge such as helium gas in the discharge space S. The excimer lamp 5 having such a configuration In the case of 0, for example, the ultraviolet ray reflection film 20 is provided on all the inner circumferences of the inner surface of the inner tube 5 3 of the discharge vessel 5 1 , and the inner surface of the outer tube 520 is formed on the inner surface of the outer tube 5 2 except for a part of the light exit portion 58. The ultraviolet ray reflection film 20 is provided outside the field. The excimer lamp 40 shown in Fig. 7 is formed, for example, by a discharge vessel 4 1 having a rectangular cross section formed of synthetic cerium oxide glass, and a pair of outer sides formed of metal The electrodes 4 5, 4 5 are disposed on the outer surface of the discharge vessel 41 facing each other so as to extend in the tube axis direction of the discharge vessel 4 1 , and for example, helium gas of the discharge gas is filled in the discharge vessel 41 . In Fig. 7, reference numeral 42 is an exhaust pipe' and reference numeral 43 is a getter formed as a crucible. In the excimer lamp 40 of such a configuration, the fields of the respective outer electrodes 4 5 and 45 corresponding to the inner surface of the discharge vessel 4 1 and all the fields of the inner surface field of one of the continuous fields are provided. The ultraviolet ray reflection film 20 is formed by not providing the ultraviolet ray reflection film 20 to form the light exit portion 44. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing an example of an example of an excimer lamp of the present invention. FIG. 1(a) is a cross section along the longitudinal direction of the discharge vessel. The sectional view, (b) is a cross-sectional view taken along line AA of (a). Fig. 2 is a graph showing the excimer discharge luminescence spectrum of an excimer lamp in which helium gas is enclosed. Fig. 3 is an explanatory view showing the definition of the particle diameter of the cerium oxide particles and the alumina particles. Fig. 4 is a graph showing the relationship between the intensity of reflected light of a specific wavelength of the ultraviolet ray reflection film produced in the experimental example and the concentration of the impurity metal contained in the ultraviolet ray reflection film. Fig. 5 is a view for explaining the principle of measurement of an apparatus for measuring the intensity of reflected light for the ultraviolet reflective film produced in the experimental example. Figure 6 is a cross-sectional view showing a schematic configuration of another example of the excimer lamp of the present invention, and (a) is a cross-sectional view showing a cross section along the longitudinal direction of the discharge vessel, (b) (a) is a cross-sectional view taken along line AA of Fig. 7A, and Fig. 7 is a cross-sectional view showing a schematic configuration of another example of the excimer lamp of the present invention, and (a) is a view along the longitudinal direction of the discharge vessel. A cross-sectional view of the cross section, and (b) is a cross-sectional view showing a cross section perpendicular to the plane of the paper surface of (a). [Explanation of main component symbols] 1 0 : Excimer lamp-21 - 200917324 1 1 : Discharge capacitor 15: - Square electrode (high voltage supply electrode) 1 6 : The other electrode (ground electrode) 1 8 : Light exit portion (Aperture portion) 20 : Ultraviolet reflection film 3 〇: Aluminum container 3 1 : Support table 3 5 : Ultraviolet illuminance meter 40 : Excimer lamp 4 1 : Discharge capacitor 42 : Exhaust pipe 4 3 : Getter 44 : Light Exit portion 45: Outer electrode 5 0 : Excimer lamp 5 1 : Discharge capacitor 5 2 : Outer tube 5 3 : Inside tube 55: - Square electrode (high voltage supply electrode) 5 6 : The other electrode 5 8 : Light Exit portion 60: Dihydrogen lamp 61: Concave grating 62: Slotted-22- 200917324 65: Photographic plug-in accessory TS: Test piece S: Discharge space-23