200925775 九、發明說明： 【發明所屬之技術領域】 本發明係關於使用光罩而在被轉印體上的光阻i 設有不同阻劑膜厚部分之轉印圖案的圖案轉印方法、 案轉印方法所使用之灰階光罩及其製造方法、以及薯 灰階光罩所使用的灰階光罩坯料。 【先前技術】 目前，在液晶顯示裝置（Liquid Crystal Display : 稱之爲LCD )的領域中，薄膜電晶體液晶顯示裝置< Film Transistor Liquid Crystal Display :以下稱 TFT-LCD )相較於CRT (陰極射線管），具有容易形 薄型且消耗電力較低的優點，因而在目前商品化乃急 展中。TFT-LCD係具有在排列成矩陣狀的各像素上劫 TFT的構造的TFT基板、及與各像素相對應，排列窄 綠及藍之像素圖案的彩色濾光片在有液晶相介於其間 相疊合的槪略構造。在TFT-LCD中，製造步驟數多， TFT基板亦使用了 5至6片光罩來製造。在這樣的形 ，已提案有藉由使用具有遮光部、透光部及半透光音丨 罩（稱爲灰階光罩），以刪減在製造TFT基板時所甲 光罩片數的方法（例如日本特開2 005-3 7933號公報） 在此’所謂灰階光罩係指具有：露出透明基板序 部；在透明基板上形成有用以將曝光光遮光之遮光瑕 光部；及在透明基板上形成有遮光膜或半透光膜，用 明基板的光透過率設爲100%時，使透過光量減低而笼 形成 該圖 造該 以下 Thin 之爲 成爲 速發 列有 紅、 之下 光是 :況下 的光 用的 〇 透光 :的遮 '將透 丨過預 200925775 定量的光之半透光部（以下亦稱之爲灰階部）者。此外， 所謂半透光部係指當使用光罩而將圖案轉印在被轉印體時 ，使所透過的曝光光的透過率減低預定量，以控制被轉印 體上之光阻膜在顯影後的殘膜量的部分。以這樣的灰階光 罩而言，係有在透明基板上形成具有預定光透過率之半透 光膜者作爲半透光部，或者在透明基板上之遮光膜或半透 光膜，在曝光條件下形成有解析界限以下之微細圖案者。 第1圖係用以說明使用灰階光罩之圖案轉印方法的剖 面圖。第1圖所示之灰階光罩20係用以在被轉印體30上 形成膜厚呈階段性不同的阻劑圖案33者。在第1圖中係顯 示使用灰階光罩20,在被轉印體30上形成有膜厚不同之阻 劑圖案33的狀態。其中，第1圖中的元件符號32A、32B 係表示在被轉印體30中層積在基板31上的膜。 第1圖所示之灰階光罩20係具有：使用該灰階光罩20 時使曝光光遮光（透過率大致爲〇%)的遮光部21;露出透 明基板24表面且使曝光光透過的透光部22;及當將透光部 的曝光光透過率設爲100%時使透過率減低爲10至80%左 右的半透光部23。第1圖所示之半透光部23係由形成在透 明基板24上之光半透過性的半透光膜所構成，但是亦可形 成當使用光罩時在曝光條件下超過解析界限之微細圖案而 構成。 當使用如上所述之灰階光罩20時，在遮光部21曝光 光並未實質透過，在半透光部23曝光光將減低。因此，塗 佈在被轉印體30上的阻劑膜（正型光阻膜）係在轉印後’ 200925775 經過顯影時，形成在與遮光部21相對應的部分具有較厚的 膜厚，在與半透光部23相對應的部分具有較薄的膜厚，在 與透光部22相對應的部分，並未具有膜（亦即實質上未產 生殘膜）的阻劑圖案3 3。亦即，阻劑圖案3 3係具有呈階段 性不同（亦即具有段差）的膜厚。 接著，在第1圖所示之阻劑圖案33之不存在膜的部分 ，對被轉印體30中之例如膜32A及32B實施第1蝕刻，藉 由灰化（ashing )等將阻劑圖案33之膜厚較薄的部分去除 ，且在該部分，對被轉印體30中之例如膜32B實施第2蝕 刻。如此一來，使用1片灰階光罩20,在被轉印體30上形 成膜厚呈階段性不同的阻劑圖案33，藉此實’施習知之光罩 2片份的步驟，而刪減光罩片數。 如上所示之光罩係極爲有效適用於製造顯示裝置，尤 其是液晶顯不裝置的薄膜電晶體。例如1可藉由遮光部21 形成源極、汲極部，藉由半透光部23形成通道部。 【發明内容】 (發明所欲解決之課題） 但是，一般在使用光罩而曝光於被轉印體時，係必須 考慮到因曝光光的反射所造成的不良影響。例如，曝光光 在透過光罩後在被轉印體表面反射，在光罩表面（圖案形 成面）或背面反射，而再次照射在被轉印體的情形。此外 ，曝光光在曝光機內的任何部位中反射，其在光罩表面反 射，而照射在被轉印體上等，藉此亦會有產生散射光的情 形。如上所示之情形，在被轉印體會產生非本意的映入， 200925775 而妨礙正確的圖案轉印。因此，在曝光機的光學系 係會施行曝光時的散射光對策。此外，在曝光機係 如光罩對曝光光的表面反射率若爲10±5%，則可在 散射光的影響的情形下進行轉印的基準。此外，在 式光罩（binary mask)等所示未具有半透光膜的光 亦必須藉由施行在作爲最上層的遮光膜設置反射防 之反射防止措施，使用使上述表面反射率15 %以下 十分充足之類的光罩。 另一方面，如上所述已知一種以在被轉印體上 有膜厚呈階段性或連續性不同的部分的阻劑圖案的 下，就圖案上的特定部位選jf性地減低曝光光的透 而可控制曝光光之透過的光罩的灰階光罩。在如此 光罩中，係已知一種在透過曝光光之一部分的半透 用半透光膜者。在該半透光部使用半透光膜的灰階 ，係藉由形成在光罩的圖案構成，使該半透光膜取 膜，如第1圖所示，存在有在光罩的最上層露出的 該半透光膜係基於在所希望的透過率範圍內透過曝 必要性，並無法適用直接層積如上述之二元式光罩 反射防止膜。此外，在使用半透光膜的灰階光罩中 光部對曝光光的表面反射率係依其組成及膜厚，亦 避免超過10%的情形。 相反地，使用如上所示之灰階光罩，在被轉印 圖案轉印時，以被轉印體上之阻劑而言，相較於未 半透光部之一般的二元式光罩等光罩，可使用敏感 統一般 設有例 不會有 如二元 罩中， 止膜等 之基準 形成具 目的之 過率， 之灰階 光部使 光罩中 代遮光 部分。 光光的 之類的 ，半透 有無法 體進行 存在有 度的曝 200925775 光光量依存性較小、或顯影特性之曝光光量依存性較低者 。如上所示，藉由使用曝光光量依存性較低的阻劑，可較 爲容易地將阻劑的殘膜量控制在所希望的範圍內。在曝光 光量依存性較低的阻劑中，由於對其光量之光敏感度的變 化較小，因此因曝光時之散射光而映入至圖案的影響係比 較小。但是，發明人發現到如此之灰階光罩中的反射特性 係有必要以有別於上述二元式光罩的觀點來進行檢討。 具體而言，如上所述，因半透光膜的曝光光反射率所 造成之散射光的影響較小，但是在製造灰階光罩的階段中 ，對用在圖案化之描繪光的表面反射率可知係極爲重要的 。其係基於當藉由描繪光在形成於半透光膜上的阻劑膜描 繪圖案時，若半透光膜表面中的表面反射率過高，即無法 正確描繪圖案的尺寸之故。 亦即，發現若半透光膜對描繪光的表面反射率較大， 對形成在半透光膜上的阻劑膜進行圖案描繪時，在灰階光 罩坯料的阻劑膜內，容易發生因描繪光而起的駐波，在阻 劑膜的厚度方向，曝光量會成爲不均一，因此使得所形成 的阻劑圖案的剖面形狀混亂，且線寬變得不均一。此外， 亦可知將具有不均一線寬的阻劑圖案作爲光罩所形成的半 透光膜的圖案，或者其更加下方之遮光膜的圖案的線寬精 度容易劣化。此外，亦發現當對灰階光罩坯料進行圖案描 繪時，在阻劑膜及其下層（在此例如爲半透光膜）的界面 中，若描繪光的反射光量較大，其部位附近的阻劑的曝光 量會變大。實際上，該效果之呈現方式亦依膜的折射率與 -10- 200925775 膜厚而受到影響，呈現較大影響時，結果圖案線寬產生變 化亦在實驗中獲得確定。 例如’在液晶顯示裝置製造用灰階光罩中，係大部分 以圖案線寬（以下簡稱爲CD)變動爲±0.35 # m以下作爲標 準規格，但是該變動目前變爲±0.3 0// m左右，尤其在薄膜 電晶體之通道部等部位中，係按照其圖案的微細化，使CD 變動達成±0.20 左右乃係實質上所需求的。尤其在薄膜 0 電晶體製造用灰階光罩中，在通道部的線寬未達3#m的情 形下，係需要如上所示之嚴謹的規格。例如，在通道寬度 爲未達2 /z m之薄膜電晶體，係必須有±0.20 m程度以內 ' 的CD分布。當超出該範圍而在CD發生變動時，係在形成 光罩之後，亦可藉由缺陷修正的手法來修正該圖案所產生 的CD誤差，但是修正步驟係作爲附加步驟而另外成爲發 生缺陷或成本上升的原因，因此以生產盡量不需要修正的 光罩爲宜。因此，備妥可減低上述CD變動的灰階光罩坯 φ 料係極爲重要的。 本發明係鑑於上述習知的情形所硏創者，其第1目的 係提供在製作灰階光罩時可減低上述CD變動的灰階光罩 坯料。 本發明之第2目的係提供使用如上所示之灰階光罩， 可精度佳地形成上述CD之灰階光罩之製造方法及灰階光 罩。 本發明之第3目的係提供使用如上所示之灰階光罩’ 可在被轉印體上形成高精度之轉印圖案的圖案轉印方法。 -11- 200925775 (解決課題之手段） 爲了解決上述課題，本發明係具有以下構成。 (構成1) 一種灰階光罩坯料，係用於製造依部位而 選擇性地減低曝光光對被轉印體的照射量，而在被轉印體 上的光阻形成包含有殘膜値不同的部分之所希望的轉印圖 案的灰階光罩的灰階光罩坯料，其特徵爲：該灰階光罩坯 料係在透明基板上依序具有半透光膜與遮光膜，在該半透 0 光膜與該遮光膜分別施行預定的圖案化，形成遮光部、半 透光部，而形成爲灰階光罩者，前述遮光膜係在膜厚方向 使組成產生變化，減低對在圖案化時形成在該遮光膜上的 阻劑膜進行圖案曝光時所使用的描繪光的表面反射率，前 述半透光膜係以對在圖案化時形成在該半透光膜上的阻劑 膜進行圖案曝光時所使用的描繪光的表面反射率在面內不 會超過45%的方式作調整。 (構成2)如構成1之灰階光罩坯料，其中，前述半 Q 透光膜係以對在圖案化時形成在該半透光膜上的阻劑膜進 行圖案曝光時所使用的描繪光的表面反射率在面內不會超 過30 %的方式作調整。 (構成3)如構成1或2之灰階光罩坯料，其中，前 述半透光膜對使用在前述灰階光罩坯料施行圖案化所成之 灰階光罩時所適用的曝光光的表面反射率爲10%以上。 (構成4)如構成1至3中任一者之灰階光罩坯料， 其中，在前述半透光膜與前述遮光膜分別圖案化時，對於 阻劑膜所使用的描繪光均爲300nm至45 0nm之範圍內之預 -12- 200925775 定波長的光。 (構成5)如構成1至4中任一者之灰階光罩坯料， 其中，前述遮光膜係藉由層積組成不同的膜所成，或在膜 厚方向形成組成傾斜所成，藉此，組成在膜厚方向產生變 化。 (構成6)如構成1至5中任一者之灰階光罩坯料， 其中，前述灰階光罩坯料係對包含365nm至436nm之範圍 之預定區域的曝光光所使用者。 (構成7) —種灰階光罩之製造方法，係具有透光部 、遮光部及透過曝光光之一部分的半透光部的灰階光罩之 製造方法，係依部位選擇性地減低曝光光對被轉印體的照 射量，而在被轉印體上的光阻形成包含有殘膜値不同的部 分之所希望的轉印圖案的灰階光罩，其特徵爲：備妥在透 明基板上依序具有半透光膜與遮光膜的灰階光罩坯料，在 該半透光膜與該遮光膜施行預定的圖案化，形成爲灰階光 罩，前述遮光膜係在膜厚方向使組成產生變化，藉此減低 在圖案化時對形成在該遮光膜上的阻劑膜進行圖案曝光的 描繪光的表面反射率，前述半透光膜係以在圖案化時對形 成在該半透光膜上的阻劑膜進行圖案曝光時所使用的描繪 光的表面反射率在面內不會超過45 %的方式作調整》 (構成8)如構成7之灰階光罩之製造方法，其中， 包含：在形成於前述遮光膜上的第1阻劑膜，使用描繪光 描繪第1圖案，將顯影後所形成的第1阻劑圖案作爲光罩 ，將該遮光膜進行蝕刻而進行第1圖案化，將該第1阻劑 -13- 200925775 圖案去除，在包含局部露出之半透光膜的基板上，形成第 2阻劑膜，在該第2阻劑膜使用前述描繪光描繪第2圖案， 將顯影後所形成的第2阻劑圖案作爲光罩，將該半透光膜 進行蝕刻而進行第2圖案化的步驟，前述遮光膜係減低對 在描繪前述第1及第2圖案時之描繪光的表面反射率，而 且前述半透光膜係以將前述第2圖案對於圖案化時之描繪 光的表面反射率在面內不會超過45 %的方式作調整。 ©(構成9) 一種灰階光罩之製造方法，係具有透光部 、遮光部及透過曝光光之一部分的半透光部的灰階光罩之 製造方法，係依部位選擇性地減低曝光光對被轉印體的照 射量，而在被轉印體上的光阻形成包含有殘膜’値不同的部 分之所希望的轉印圖案的灰階光罩，且其特徵爲：在透明 基板上形成遮光膜之後施行第1圖案化，在包含經圖案化 之遮光膜的基板全面形成半透光膜，在形成該半透光膜後 施行第2圖案化，藉此在該半透光膜與該遮光膜分別施行 _ 預定的圖案化而形成爲灰階光罩，前述遮光膜係減低在進 行第1圖案化時對在形成於該遮光膜上的阻劑膜進行圖案 曝光時所使用之描繪光的表面反射率，前述半透光膜係在 進行第2圖案化時，以對形成於既形成在前述遮光膜之上 之該半透光膜上的阻劑膜進行圖案曝光時所使用之描繪光 的表面反射率在面內不會超過45 %的方式作調整。 (構成10)如構成7至9中任一者之灰階光罩之製造 方法，其中，前述半透光膜係以對使用前述灰階光罩時所 適用的曝光光的表面反射率爲10 %以上的方式作調整。 -14 - 200925775 (構成11)如構成7至10中任一者之之灰階光罩之製 造方法，其中，前述半透光膜之對於前述描繪光的表面反 射率係以在面內不會超過3 0 %的方式作調整。 (構成12)如構成7至11中任一者之灰階光罩之製造 方法，其中，在前述半透光膜與前述遮光膜分別進行圖案 化時，針對阻劑膜所使用的描繪光均爲300nm至450nm之 範圍內之預定波長的光。 (構成13)如構成7至12中任一者之灰階光罩之製造 方法，其中，前述遮光膜係藉由層積組成不同的膜而成者 ，或在膜厚方向形成組成傾斜者。 (構成14)如構成7至13片任一者之灰階光罩之製造 方法，其中，前述灰階光罩係針對包含365nm至436nm之 範圍的預定區域的曝光光所使用者。 (構成15) —種灰階光罩，其特徵爲：係藉由構成7 至14中任一者之灰階光罩之製造方法所製造。 (構成16)如構成15之灰階光罩，其中，相對於預定 線寬的線寬偏差爲±0.35 # m以內。 (構成17) —種圖案轉印方法，其特徵爲：具有使用 藉由構成7至14中任一者之製造方法所得之灰階光罩，對 被轉印體照射曝光光的曝光步驟，在被轉印體上形成包含 有殘膜値不同之部分的預定的轉印阻劑圖案。 本發明之灰階光罩坯料係用於製造依部位而選擇性地 減低曝光光對被轉印體的照射量，而在被轉印體上的光阻 形成包含有殘膜値不同的部分之所希望的轉印圖案的灰階 -15- 200925775 光罩的灰階光罩坯料，形成在透明基板上的遮光膜係組成 在膜厚方向改變。藉此減低對描繪光的表面反射率。此外 ，半透光膜係以對描繪光的表面反射率爲45 %以下的方式 作調整。此外，灰階光罩坯料的半透光膜係以在描繪時對 描繪光之表面反射率爲30%以下的方式作調整爲宜。藉此 ，即使針對如通道部之類之需要精度的部分，亦可正確地 重現形成在光罩的圖案的CD，可減低其變動。接著，獲得 ^ 可達成按照光罩上之圖案的CD變動，例如圖案之微細化 ❹ 之需求的預定的標準規格的灰階光罩。此外，使用所得之 灰階光罩，在對被轉印體進行圖案轉印時，亦不會有因曝 光光反射所造成之散射光的影響，可得良好的轉印特性。 此外，使用精度佳地形成有圖案的CD的上述灰階光 罩來進行圖案轉印，藉此可在被轉印體上形成高精度的轉 印圖案。 【實施方式】 D 以下根據圖示，說明用以實施本發明之最佳形態。 (第1實施形態） 第2圖係顯示本實施形態之灰階光罩之製造步驟的剖 面圖。在本實施形態中，係就製造具備有遮光部、透光部 、及半透光部的TFT基板製造用灰階光罩的情形加以說明 〇 本實施形態所使用的灰階光罩坯料係在透明基板24 上依序形成有：例如含有鉬矽化物的半透光膜26、及例如 以鉻Cr爲主成分的遮光膜25,在其上塗佈阻劑而形成有阻 16 - 200925775 劑膜27 (參照第2圖（a))。以遮光膜25的材質而言， 除了上述以Cr爲主成分的材料之外，列舉有Si、W、A1 等。在本實施形態中，遮光部的透過率係藉由層積上述遮 光膜25與後述的半透光膜26而決定，藉由選定各自的膜 材質與膜厚，總和而言設定爲光學濃度3.0以上。 首先進行第1次描繪。在描繪時，通常大部分係使用 電子線或光（單一波長光），但是在本實施形態中係使用 雷射光（300至450nm之範圍內的預定波長光，例如413nm 、3 5 5 nm等）。以上述阻劑而言係使用正型光阻。對遮光 膜25上的阻劑膜27描繪預定的元件圖案（在與遮光部相 對應的區域形成阻劑圖案之類的圖案），在描繪後進行顯 影，藉此形成與遮光部的區域相對應的阻劑圖案27 (參照 第2圖（b))。 接著，將上述阻劑圖案27作爲鈾刻光罩，將遮光膜 25進行蝕刻而形成與遮光部區域相對應的遮光膜圖案，使 形成半透光部的半透光膜及與透光部的區域相對應的半透 光膜露出。當使用以鉻爲主成分的遮光膜25時，以蝕刻手 段而言，可使用乾式蝕刻或濕式蝕刻之任一者，但在本實 施形態中係利用乾式蝕刻。所殘留的阻劑圖案係予以去除 (參照第2圖（c ))。 接著，在基板全面形成與第1次阻劑膜相同的阻劑膜 ，進行第2次描繪。在第2次描繪中係以在遮光部及半透 光部上形成有阻劑圖案的方式描繪預定圖案。在透光部形 成區域中，係在半透光膜26上的阻劑膜照射描繪光。描繪 -17- 200925775 後，藉由進行顯影，在與遮光部及半透光部相對 上形成阻劑圖案28(參照第2圖（d))。 接著，將上述阻劑圖案28作爲蝕刻光罩而將 透光部區域上的半透光膜26進行蝕刻，而形成透 照第2圖（e))。接著，將所殘留的阻劑圖案去 在透明基板24上具有由半透光膜26與遮光膜25 所構成的遮光部21、露出透明基板24的透光部 半透光膜26所構成的半透光部23的灰階光罩（ 圖（f))。 如第2圖（a)所示，本發明之灰階光罩坯料 基板24上依序具有半透光膜26與遮光膜25。上 罩坯料（第2圖（a))中的半透光膜26係具有 板24之曝光光之透過率爲10至80 %左右的透過 形成爲20至60 %的透過量爲佳。以上述半透光崔 質而言，係列舉鉻化合物、、Mo化合物、Si、W、 鉻化合物而言，係有氧化鉻（CrOx )、氮化鉻（ 氮氧化鉻（CrOxN )、氟化鉻（CrFx )、或在該等 氫者，以Mo化合物而言，除了 MoSix以外，另外 之氮化物、氧化物、氮氧化物、碳化物等。此外 之光罩上的半透光部的透過率係藉由選定上述半 的膜材質與膜厚而設定。在此係在第2圖（c)中 光膜26上的遮光膜25進行蝕刻，因此最好在半 遮光膜具有對蝕刻劑的蝕刻選擇性才較爲有利。 半透光膜的素材係以Mo化合物爲佳而採用Mo Si 應的區域 所露出的 光部（參 除’完成 的層積膜 22、及由 參照第2 係在透明 述灰階光 對透明基 量者，以 I 26之材 A1等。以 CrNx)、 含有碳或 含有MoSi ，所形成 透光膜26 ，將半透 透光膜與 因此，在 x(透過率 -18- 200925775 50% )。 另一方面，遮光膜25係使用以Cr爲主成分的素材， 具體而言，遮光膜25係具備有以在膜厚方向使組成產生變 化的構成。例如以遮光膜25而言，可適用在由金屬鉻所構 成的層上層積有氧化鉻（Cr Ox )者，或在由金屬鉻所構成 的層上層積有氮氧化鉻（CrOxNy )者，或在由氮化鉻（CrNx )所構成的層上層積有金屬鉻、氧化鉻（CrOx )者等。在 此，藉由層積所形成的遮光膜25可爲具有明確交界的層積 ’或者亦包含不具有明確交界之藉由組成傾斜而成者。藉 由調整該組成及膜厚，可減低對描繪光的表面反射率。遮 光膜25對描繪光的表面反射率係可形成爲1〇至15%左右 。因此，在前述第1次描繪步驟（第2圖（b))中，可抑 制描繪在遮光膜25上之阻劑膜時之CD變動。其中，以如 上所示之遮光膜25而言，亦可適用施行有對曝光光之反射 防止功能之習知的遮光膜。 在本發明中，上述半透光膜26的特徵爲以對描繪光的 表面反射率爲45 %以下的方式作調整。藉此，在前述之第2 次描繪步驟（第2圖（D))中，可減低描繪在半透光膜 26上之阻劑膜時半透光膜26對CD變動之表面反射率的影 響。其中，在此所適用的描繪光係可適用300至45 Onm的 預定波長，且最好使用適於此的光阻。 如以上説明所示，使用如上所示之灰階光罩坯料，按 照上述第2圖的步驟來製造灰階光罩，藉此可減低光罩上 之圖案的CD及半透光膜對其變動之表面反射率的影響， -19- 200925775 因此結果可將光罩圖案的CD正確地重現爲所希望値’可 輕易地達成按照圖案微細化的需求之預定的標準規格。此 外，使用所得灰階光罩來對被轉印體進行圖案轉印時’亦 可減低因曝光光反射所造成之散射光的影響。 使用由以上實施形態所得之精度佳地形成光罩圖案的 CD，而且可減低圖案轉印時之散射光的影響的上述灰階光 罩，對第1圖所示之被轉印體30進行圖案轉印，藉此可在 Λ 被轉印體上形成高精度的轉印圖案（阻劑圖案33 )。 其中，第1圖及第2圖所示之遮光部21、透光部22、 及半透光部23的圖案形狀僅爲具代表性之一例，當然並非 意旨將本發明限定於此。 ’ (第2實施形態） 第3圖係顯示本實施形態之灰階光罩之製造步驟的剖 面圖。在本實施形態中亦就製作具備有遮光部、透光部、 及半透光部的TFT基板製造用灰階光罩的情形作說明。 Q 如第3圖（a )所示，所使用的光罩坯料係在透明基板 24上形成以例如鉻Cr爲主成分的遮光膜25，在其上塗佈 阻劑而形成有阻劑膜27，在該狀態下，並未形成有半透光 膜。以遮光膜25的材質而言，除了以上述Cr爲主成分的 材料以外，列舉Si、W、A1等。在本實施形態中，遮光部 的透過率係藉由層積上述遮光膜25與後述的半透光膜26 而決定’選由選定各自的膜材質與膜厚，總和而言設定爲 光學濃度3 · 0以上。其中’在本實施形態中，如以下説明 所示，在形成上述遮光膜25的圖案之後，在包含該遮光膜 -20- 200925775 圖案的基板全面形成半透光膜。 首先進行第1次描繪。以上述阻劑而言係使用正 阻。接著，對遮光膜25上的阻劑膜27描繪預定的元 案（形成與遮光部及透光部的區域相對應的阻劑圖案 的圖案）。 在描繪後藉由進行顯影，形成與遮光部及透光部 應的阻劑圖案27 (參照第3圖（b ))。 ^^接著，以上述阻劑圖案27爲蝕刻光罩，將遮光月 0 進行鈾刻而形成遮光膜圖案。當使用以鉻爲主成分的 膜25時，以蝕刻手段而言，可爲乾式蝕刻或濕式蝕刻 一者，但在本實施形態中係利用濕式蝕刻。 在將所殘留的阻劑圖案去除之後（參照第3圖（ ，在包含透明基板24上之遮光膜圖案的全面形成半透 26 (參照第3圖（d ))。半透光膜26係具有對透明 24之曝光光之透過量爲10至80%左右的透過量，以 g 20至60 %之透過率者爲更佳。在本實施形態中係採用 濺鍍成膜所得之含有氧化鉻的半透光膜（曝光光透 4 0%)。 在此，遮光膜25係與實施態樣1相同，可適用施 減低表面反射率之措施者。此外，上述半透光膜26係 述相同地，以對描繪光的表面反射率爲45 %以下的方 調整。 接著，在上述灰階光罩坯料的半透光膜26上形成 劑膜27相同的阻劑膜，在該半透光膜26上的阻劑膜 型光 件圖 之類 相對 莫25 遮光 之任 c)) 光膜 基板 具有 藉由 過率 行有 與上 式作 與阻 進行 -21- 200925775 第2次描繪。在第2次描繪中，係以在遮光部及半透光 上形成有阻劑圖案的方式描繪預定圖案。在描繪後，藉 進行顯影，在與遮光部及半透光部相對應的區域形成阻 圖案28 (參照第3圖（e))。上述半透光膜26係以對 繪光的表面反射率爲45 %以下的方式作調整，因此可減 半透光膜26對描繪在半透光膜26上之阻劑膜時之CD變 的表面反射率的影響。其中，在此可使用與上述第1次 繪相同的描繪光作爲描繪光。 接著，以上述阻劑圖案28爲蝕刻光罩，將所露出的 透光膜26與遮光膜25的層積膜進行蝕刻而形成透光部 。以此時的蝕刻竽段而言，在本實施形態中係利用濕式 刻。接著，將殘留的阻劑圖案去除，完成在透明基板24 4 具有由遮光膜25與半透光膜26的層積膜所構成的遮光 21、露出透明基板24的透光部22、及由半透光膜26所 成的半透光部23的灰階光罩（參照第3圖（f))。 但是，在上述第1及第2實施形態中，若根據本發 人的檢討，在一般所使用的光罩中，對描繪光的表面反 率對線寬CD所造成的影響係如以下所示。 在第4圖顯示對表面反射率之線寬CD的變動傾向 以上述圖案化所使用之描繪光而言，係有使用波長300 45〇nm的雷射光，例如413nm之波長的雷射光的情形。 第4圖中係顯示使用與上述雷射光近似之43 6nm的波長 雷射光的情形的測定結果。第4圖係顯示將使用該雷射 時之反射率的容許範圍，以反射率與線寬的關係進行驗 部 由 劑 描 低 動 描 半 22 蝕 上 部 構 明 射 至 在 的 光 證 -22- 200925775 的結果。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern transfer method of a transfer pattern in which a photoresist film having a different resist film thickness portion is provided on a light-receiving member on a transfer target using a photomask. A gray scale mask used in the transfer method, a method of manufacturing the same, and a gray scale mask blank used in the potato ash mask. [Prior Art] At present, in the field of liquid crystal display devices (LCDs), thin film transistor liquid crystal display devices < Film Transistor Liquid Crystal Display: hereinafter referred to as TFT-LCD) are compared with CRT (cathode) The ray tube has the advantages of being easy to form thin and having low power consumption, and thus is currently in the process of commercialization. A TFT-LCD has a TFT substrate having a structure in which TFTs are arranged in a matrix, and a color filter in which pixel patterns of narrow green and blue are arranged corresponding to respective pixels in a liquid crystal phase interposed therebetween The overlapping structure of the overlay. In the TFT-LCD, the number of manufacturing steps is large, and the TFT substrate is also manufactured using 5 to 6 masks. In such a form, it has been proposed to reduce the number of masks in the manufacture of a TFT substrate by using a light-shielding portion, a light-transmitting portion, and a semi-transmissive sound cover (referred to as a gray scale mask). (Japanese Unexamined Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. A light-shielding film or a semi-transmissive film is formed on the transparent substrate. When the light transmittance of the bright substrate is 100%, the amount of transmitted light is reduced, and the cage is formed into a pattern. Light is: the light used in the case of light transmission: the cover 'will pass through the pre-200925775 quantitative light semi-transmission part (hereinafter also referred to as the gray level part). In addition, the semi-transmissive portion means that when a pattern is transferred to a transfer target by using a photomask, the transmittance of the transmitted exposure light is reduced by a predetermined amount to control the photoresist film on the transfer target. The portion of the residual film amount after development. In the case of such a gray scale mask, a semi-transmissive film having a predetermined light transmittance on a transparent substrate is used as a semi-transmissive portion, or a light-shielding film or a semi-transparent film on a transparent substrate is exposed. Under the condition, a fine pattern having a resolution limit or less is formed. Fig. 1 is a cross-sectional view for explaining a pattern transfer method using a gray scale mask. The gray scale mask 20 shown in Fig. 1 is for forming a resist pattern 33 having a different film thickness on the transfer target body 30. In the first drawing, a state in which the resist pattern 33 having a different film thickness is formed on the transfer target 30 is shown using the gray scale mask 20. Here, the reference numerals 32A and 32B in the first drawing denote the film laminated on the substrate 31 in the transfer target body 30. The gray scale mask 20 shown in Fig. 1 has a light shielding portion 21 that shields exposure light (a transmittance of approximately 〇%) when the gray scale mask 20 is used, and exposes the surface of the transparent substrate 24 and transmits the exposure light. The light transmitting portion 22; and the semi-light transmitting portion 23 which reduces the transmittance to about 10 to 80% when the exposure light transmittance of the light transmitting portion is 100%. The semi-transmissive portion 23 shown in Fig. 1 is composed of a semi-transmissive semi-transparent film formed on the transparent substrate 24, but may also form a fineness exceeding the resolution limit under exposure conditions when the photomask is used. Made up of patterns. When the gray scale mask 20 as described above is used, the exposure light is not substantially transmitted through the light blocking portion 21, and the exposure light is reduced in the semi-light transmitting portion 23. Therefore, the resist film (positive type resist film) coated on the transfer target body 30 is formed to have a thick film thickness at a portion corresponding to the light shielding portion 21 when developed after the transfer '200925775', The portion corresponding to the semi-transmissive portion 23 has a thin film thickness, and the portion corresponding to the light transmitting portion 22 does not have a resist pattern 3 3 which is a film (that is, a residual film is not substantially generated). That is, the resist pattern 33 has a film thickness which is different in stages (i.e., has a step). Next, in the portion where the film is not present in the resist pattern 33 shown in Fig. 1, the first etching is performed on, for example, the films 32A and 32B in the transfer target 30, and the resist pattern is formed by ashing or the like. A portion having a thin film thickness of 33 is removed, and in this portion, for example, the film 32B in the transfer target body 30 is subjected to the second etching. In this manner, a resist pattern 33 having a different film thickness is formed on the transfer target 30 by using one piece of the gray scale mask 20, thereby realizing the step of applying the known photomask 2 pieces. The number of masks. The reticle as shown above is extremely effective for the manufacture of a display device, particularly a thin film transistor of a liquid crystal display device. For example, the source and the drain are formed by the light shielding portion 21, and the channel portion is formed by the semi-transmissive portion 23. SUMMARY OF THE INVENTION (Problems to be Solved by the Invention) However, in general, when a photomask is used and exposed to a transfer target, it is necessary to take into consideration adverse effects due to reflection of exposure light. For example, the exposure light is reflected on the surface of the transfer target after passing through the reticle, and is reflected on the surface of the reticle (pattern formation surface) or the back surface, and is irradiated again to the object to be transferred. Further, the exposure light is reflected in any portion of the exposure machine, which is reflected on the surface of the reticle, and is irradiated onto the object to be transferred, etc., whereby the scattered light is generated. In the case shown above, unintentional reflection occurs in the transferred body, and 200925775 hinders proper pattern transfer. Therefore, the optical system of the exposure machine performs countermeasures against scattered light during exposure. Further, when the surface reflectance of the exposure machine such as the photomask to the exposure light is 10 ± 5%, the reference for transfer can be performed under the influence of the scattered light. In addition, light having no semi-transmissive film as shown in a binary mask or the like must be provided by performing reflection prevention on the light-shielding film as the uppermost layer, and the surface reflectance is 15% or less. A very sleek mask. On the other hand, as described above, it is known that a resist pattern having a portion having a film thickness different in stage or continuity on the object to be transferred is selected to reduce the exposure light in a specific portion on the pattern. A gray scale reticle that can control the transmission of exposure light. In such a reticle, a semi-transmissive semi-transmissive film which is part of the transmitted light is known. In the semi-transmissive portion, the gray scale of the semi-transmissive film is used, and the semi-transmissive film is formed by the pattern formed in the photomask. As shown in FIG. 1, there is the uppermost layer of the photomask. The exposed semi-transmissive film is based on the necessity of transmitting through the desired transmittance range, and is not suitable for direct lamination such as the above-described binary reticle reflection preventing film. Further, in the gray scale mask using the semi-transmissive film, the surface reflectance of the light portion to the exposure light is also prevented from exceeding 10% depending on the composition and film thickness. Conversely, using the gray scale reticle as shown above, in the case of transfer of the transferred pattern, in the case of the resist on the transferred body, compared to the general binary mask of the non-transmissive portion For the reticle, the sensible system can be used. The refractory system does not have a target such as a binary cover, a stop film, etc., and the gray-scale light portion causes the reticle to be a light-shielding portion. Light and light, such as semi-transparent, can not be physically exposed to the degree of exposure 200925775 light light quantity dependence is small, or the development characteristics of the exposure light amount dependence is lower. As described above, by using a resist having a low dependency on the amount of exposure light, it is possible to more easily control the residual film amount of the resist within a desired range. In the resist having a low amount of exposure light, since the change in the sensitivity of the light amount to the amount of light is small, the influence of the scattered light upon exposure to the pattern is small. However, the inventors have found that the reflection characteristics in such a gray scale mask need to be reviewed in view of the difference from the above-described binary mask. Specifically, as described above, the influence of the scattered light due to the exposure light reflectance of the semi-transmissive film is small, but in the stage of manufacturing the gray scale mask, the surface reflection for the patterned light is used for reflection. The rate is extremely important. This is based on the fact that when the pattern is drawn by the resist film formed on the semi-transmissive film by drawing light, if the surface reflectance in the surface of the semi-transmissive film is too high, the size of the pattern cannot be accurately drawn. That is, it has been found that if the semi-transmissive film has a large surface reflectance to the light to be drawn, when the resist film formed on the semi-transmissive film is patterned, it is likely to occur in the resist film of the gray-scale mask blank. The standing wave due to the drawing of the light has a non-uniform exposure amount in the thickness direction of the resist film, so that the cross-sectional shape of the formed resist pattern is disordered, and the line width becomes uneven. Further, it is also known that a resist pattern having a non-uniform line width is used as a pattern of a semi-transmissive film formed by a photomask, or a line width of a pattern of a light-shielding film which is further lower is easily deteriorated. In addition, it has also been found that when the gray scale mask blank is patterned, in the interface between the resist film and its lower layer (here, for example, a semi-transmissive film), if the amount of reflected light of the depicted light is large, the vicinity of the portion is The exposure amount of the resist will become large. In fact, the effect of the effect is also affected by the refractive index of the film and the film thickness of -10-200925775. When the film has a large influence, the change of the line width of the pattern is also determined in the experiment. For example, in the gray scale mask for manufacturing a liquid crystal display device, most of the pattern line width (hereinafter abbreviated as CD) fluctuates to ±0.35 #m or less as a standard specification, but the variation is now ±0.3 0// m. In the left and right, particularly in the channel portion of the thin film transistor, the CD variation is about ±0.20 in accordance with the miniaturization of the pattern, which is substantially required. Especially in the gray scale mask for film 0 transistor manufacturing, in the case where the line width of the channel portion is less than 3 #m, the strict specifications as shown above are required. For example, in a thin film transistor with a channel width of less than 2 /z m, the CD distribution must be within ±0.20 m. When the CD is changed beyond the range, the CD error generated by the pattern can be corrected by the defect correction method after the mask is formed, but the correction step is additionally added as a defect or a cost. The reason for the rise is therefore to produce a mask that does not require correction as much as possible. Therefore, it is extremely important to prepare a gray scale mask blank φ material system which can reduce the above CD variation. SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and a first object thereof is to provide a gray scale mask blank which can reduce the above-described CD variation when a gray scale mask is produced. A second object of the present invention is to provide a method of manufacturing a gray scale mask of the above-described CD and a gray scale mask using the gray scale mask as described above. A third object of the present invention is to provide a pattern transfer method which can form a high-precision transfer pattern on a transfer target using the gray scale mask shown above. -11- 200925775 (Means for Solving the Problem) In order to solve the above problems, the present invention has the following configuration. (Configuration 1) A gray-scale mask blank which is used for manufacturing a portion to selectively reduce the amount of exposure of the exposure light to the object to be transferred, and the formation of the photoresist on the object to be transferred includes the residual film The gray scale mask blank of the gray scale mask of the desired transfer pattern is characterized in that: the gray scale mask blank has a semi-transparent film and a light shielding film sequentially on the transparent substrate, in the half The light-transmitting film and the light-shielding film are respectively patterned by a predetermined pattern to form a light-shielding portion and a semi-transmissive portion, and the light-shielding film is formed into a gray-scale mask, and the light-shielding film changes the composition in the film thickness direction to reduce the on-pattern. The surface reflectance of the light used when patterning the resist film formed on the light-shielding film, and the semi-transmissive film is a resist film formed on the semi-transmissive film during patterning. The surface reflectance of the light to be used for pattern exposure is adjusted so as not to exceed 45% in the plane. (Configuration 2) The gray-scale mask blank of the first aspect, wherein the semi-Q light-transmissive film is used to pattern-expose a resist film formed on the semi-transmissive film at the time of patterning. The surface reflectance is adjusted in such a way that it does not exceed 30% in the plane. (Configuration 3) A gray-scale mask blank constituting 1 or 2, wherein the semi-transmissive film is applied to a surface of an exposure light to which a gray scale mask formed by patterning the gray-scale mask blank is applied The reflectance is 10% or more. (Aspect 4) The gray scale mask blank according to any one of the above 1 to 3, wherein when the semi-transmissive film and the light shielding film are respectively patterned, the light used for the resist film is 300 nm to Pre--12-200925775 light of a fixed wavelength in the range of 45 nm. (Aspect 5) The gray-scale mask blank according to any one of the first to fourth aspect, wherein the light-shielding film is formed by a film having a different laminated composition or formed by tilting a composition in a film thickness direction. The composition changes in the direction of the film thickness. (Aspect 6) The gray-scale mask blank according to any one of 1 to 5, wherein the gray-scale mask blank is used for exposure light of a predetermined region including a range of 365 nm to 436 nm. (Configuration 7) A method of manufacturing a gray scale mask, which is a method of manufacturing a gray scale mask having a light transmitting portion, a light blocking portion, and a semi-transmissive portion that transmits a part of exposure light, and selectively reduces exposure according to a portion a gray scale mask that forms a desired transfer pattern including a portion of the residual film defect by the light resistance of the object to be transferred, and the photoresist on the object to be transferred is characterized in that it is prepared for transparency. a gray scale mask blank having a semi-transmissive film and a light shielding film on the substrate, wherein the semi-transmissive film and the light shielding film are patterned in a predetermined pattern to form a gray scale mask, and the light shielding film is in a film thickness direction Varying the composition, thereby reducing the surface reflectance of the patterned light for pattern exposure of the resist film formed on the light-shielding film during patterning, the semi-transmissive film being formed in the half during patterning The surface reflectance of the light to be used for pattern exposure on the light-transmissive film is adjusted so as not to exceed 45% in the plane. (Configuration 8) The manufacturing method of the gray scale mask of the seventh embodiment is Wherein, including: on the aforementioned light shielding film In the resist film, the first pattern is drawn using the drawing light, and the first resist pattern formed after development is used as a mask, and the light-shielding film is etched to perform first patterning, and the first resist-13- 200925775 Pattern removal, forming a second resist film on a substrate including a partially exposed semi-transmissive film, drawing a second pattern on the second resist film using the drawing light, and forming a second resist after development The pattern is a mask, and the semi-transmissive film is etched to perform a second patterning process, wherein the light shielding film reduces surface reflectance of the light to be drawn when the first and second patterns are drawn, and the semi-transparent The light film is adjusted such that the surface reflectance of the drawing light when the second pattern is patterned is not more than 45% in the plane. © (Configuration 9) A method of manufacturing a gray scale mask, which is a method of manufacturing a gray scale mask having a light transmitting portion, a light blocking portion, and a semi-transmissive portion that transmits a part of exposure light, selectively reducing exposure according to a portion The amount of light irradiated onto the object to be transferred, and the photoresist on the object to be transferred forms a gray scale mask containing a desired transfer pattern of a portion of the residual film '値, and is characterized by: being transparent After the light-shielding film is formed on the substrate, the first patterning is performed, the semi-transmissive film is formed on the substrate including the patterned light-shielding film, and the second pattern is formed after the semi-transmissive film is formed, thereby the semi-transparent The film and the light-shielding film are respectively patterned by a predetermined pattern to form a gray scale mask, and the light-shielding film is used to reduce patterning of the resist film formed on the light-shielding film when the first patterning is performed. The surface reflectance of the light is drawn, and when the second semi-transmissive film is patterned, the resist film formed on the semi-transmissive film formed on the light-shielding film is subjected to pattern exposure. The surface reflectance of the light used in the surface Adjustments will not be made in more than 45% of the way. (Claim 10) The method for producing a gray scale mask according to any one of the items 7 to 9, wherein the semi-transmissive film has a surface reflectance of 10 for exposure light to which the gray scale mask is used. More than % of the way to adjust. The method of manufacturing a gray scale mask according to any one of the items 7 to 10, wherein the surface reflectance of the semi-transmissive film with respect to the drawing light is not in-plane. More than 30% of the way to make adjustments. (Claim 12) The method for producing a gray scale mask according to any one of the items 7 to 11, wherein when the semi-transmissive film and the light-shielding film are respectively patterned, the light used for the resist film is It is light of a predetermined wavelength in the range of 300 nm to 450 nm. (Claim 13) The method for producing a gray scale mask according to any one of the items 7 to 12, wherein the light-shielding film is formed by a film having a different laminated composition, or a composition is formed in a film thickness direction. (Configuration 14) A method of manufacturing a gray scale mask comprising any one of 7 to 13 in which the gray scale mask is used for exposure light of a predetermined region including a range of 365 nm to 436 nm. (Configuration 15) A gray scale mask which is manufactured by a method of manufacturing a gray scale mask of any one of 7 to 14. (Structure 16) A gray scale mask of the composition 15, wherein the line width deviation from the predetermined line width is within ±0.35 #m. (Structure 17) A pattern transfer method characterized by having an exposure step of irradiating exposure light to a transfer target by using a gray scale mask obtained by the manufacturing method of any one of 7 to 14 A predetermined transfer resist pattern containing a portion different from the residual film enthalpy is formed on the transferred body. The gray scale mask blank of the present invention is used for manufacturing a portion to selectively reduce the amount of exposure of the exposure light to the object to be transferred, and the photoresist on the object to be transferred forms a portion containing the residual film. The gray scale mask blank of the gradation of the desired transfer pattern -15-200925775, the light-shielding film composition formed on the transparent substrate changes in the film thickness direction. This reduces the surface reflectance of the depicted light. Further, the semi-transmissive film is adjusted so that the surface reflectance of the light to be drawn is 45% or less. Further, the semi-transmissive film of the gray scale mask blank is preferably adjusted so that the surface reflectance of the light to be drawn is 30% or less at the time of drawing. Thereby, even for a portion requiring precision such as a channel portion, the CD formed in the pattern of the reticle can be accurately reproduced, and the variation can be reduced. Next, a gray scale mask of a predetermined standard size which satisfies the CD variation of the pattern on the photomask, for example, the miniaturization of the pattern, is obtained. Further, by using the obtained gray scale mask, when the transfer target is subjected to pattern transfer, there is no influence of scattered light due to reflection of the exposure light, and good transfer characteristics can be obtained. Further, pattern transfer is performed using the above-described gray scale mask in which the patterned CD is formed with high precision, whereby a highly precise transfer pattern can be formed on the object to be transferred. [Embodiment] D Hereinafter, the best mode for carrying out the invention will be described with reference to the drawings. (First Embodiment) Fig. 2 is a cross-sectional view showing a manufacturing procedure of a gray scale mask of the present embodiment. In the present embodiment, a gray scale mask for manufacturing a TFT substrate including a light shielding portion, a light transmitting portion, and a semi-light transmitting portion is described. The gray scale mask blank used in the present embodiment is The transparent substrate 24 is formed with, for example, a semi-transmissive film 26 containing molybdenum telluride, and a light-shielding film 25 containing, for example, chromium Cr as a main component, and a resist is applied thereon to form a resist film 16 - 200925775 film 27 (Refer to Figure 2 (a)). The material of the light-shielding film 25 is, in addition to the above-mentioned material containing Cr as a main component, Si, W, A1 and the like. In the present embodiment, the transmittance of the light-shielding portion is determined by laminating the light-shielding film 25 and a semi-transmissive film 26 to be described later, and the respective film materials and film thicknesses are selected, and the total density is set to an optical density of 3.0. the above. First, the first drawing is performed. In drawing, most of the electron beams or light (single-wavelength light) are used, but in the present embodiment, laser light (predetermined wavelength light in the range of 300 to 450 nm, for example, 413 nm, 35 5 nm, etc.) is used. . In the case of the above-mentioned resist, a positive type resist is used. The resist film 27 on the light-shielding film 25 is drawn with a predetermined element pattern (a pattern such as a resist pattern is formed in a region corresponding to the light-shielding portion), and development is performed after the drawing, thereby forming a region corresponding to the light-shielding portion. The resist pattern 27 (see Fig. 2(b)). Next, the resist pattern 27 is used as an uranium engraved mask, and the light-shielding film 25 is etched to form a light-shielding film pattern corresponding to the light-shielding portion region, and the semi-transmissive film forming the semi-transmissive portion and the light-transmitting portion are formed. The semi-transparent film corresponding to the area is exposed. When the light-shielding film 25 containing chromium as a main component is used, either dry etching or wet etching may be used for the etching step, but in the present embodiment, dry etching is used. The remaining resist pattern is removed (see Fig. 2(c)). Next, the same resist film as that of the first resist film was formed on the entire substrate, and the second drawing was performed. In the second drawing, a predetermined pattern is drawn so that a resist pattern is formed on the light shielding portion and the semi-transmissive portion. In the light-transmitting portion forming region, the resist film on the semi-transmissive film 26 illuminates the drawing light. After drawing -17-200925775, the resist pattern 28 is formed on the light-shielding portion and the semi-transmissive portion by development (see Fig. 2(d)). Next, the above-described resist pattern 28 is used as an etching mask to etch the semi-transmissive film 26 on the light-transmitting portion to form a transparent image (Fig. 2(e)). Next, the remaining resist pattern is provided on the transparent substrate 24 with a light-shielding portion 21 composed of the semi-transmissive film 26 and the light-shielding film 25, and a light-transmissive portion semi-transmissive film 26 exposing the transparent substrate 24. A gray scale mask of the light transmitting portion 23 (Fig. (f)). As shown in Fig. 2(a), the gray scale mask blank substrate 24 of the present invention has a semi-transmissive film 26 and a light shielding film 25 in this order. The semi-transmissive film 26 in the top cover blank (Fig. 2(a)) has a transmittance of exposure light of the plate 24 of about 10 to 80%, preferably 20 to 60%. In the above-mentioned semi-transparent Cui, the series of chromium compounds, Mo compounds, Si, W, and chromium compounds are chromium oxide (CrOx), chromium nitride (chromium oxynitride (CrOxN), chromium fluoride). (CrFx), or in the case of the hydrogen, in addition to MoSix, other nitrides, oxides, oxynitrides, carbides, etc. In addition, the transmittance of the semi-transmissive portion on the mask It is set by selecting the film material and film thickness of the above-mentioned half. Here, the light-shielding film 25 on the light film 26 in FIG. 2(c) is etched, so it is preferable to etch the etchant in the semi-shield film. Selectivity is more advantageous. The material of the semi-transmissive film is a light portion exposed by a region where Mo Si is preferably a Mo compound (refer to the completed laminated film 22 and the reference second system in the transparent For the gray scale light to the transparent base amount, the material A1 of the I26, etc., with CrNx), containing carbon or containing MoSi, the transparent film 26 is formed, and the translucent transparent film is thus, at x (transmittance - 18- 200925775 50% ) On the other hand, the light-shielding film 25 uses a material mainly composed of Cr, The light-shielding film 25 is provided with a structure that changes the composition in the film thickness direction. For example, the light-shielding film 25 can be applied to a layer in which chromium oxide (Cr Ox ) is laminated on a layer made of metallic chromium. Or a layer of chromium oxyhydroxide (CrOxNy) laminated on a layer made of metallic chromium, or a layer of chromium or chromium oxide (CrOx) laminated on a layer made of chromium nitride (CrNx). The light-shielding film 25 formed by lamination may be a laminate having a clear boundary or a composition having a clear boundary without a clear boundary. By adjusting the composition and the film thickness, the light can be reduced. The surface reflectance of the light-shielding film 25 can be set to about 1 〇 to 15% with respect to the surface reflectance of the light. Therefore, in the first drawing step (Fig. 2(b)), the shading can be suppressed. The CD of the resist film on the film 25 is varied. Among the light-shielding films 25 as described above, a light-shielding film having a function of preventing reflection of exposure light can be applied. The semi-transmissive film 26 is characterized by a surface reflectance of the pair of light 45 % or less is adjusted. Thereby, in the second drawing step (Fig. 2 (D)) described above, the semi-transmissive film 26 can be reduced when the resist film is drawn on the semi-transmissive film 26 The influence of the surface reflectance of the CD variation. Among them, the drawing light system to which this applies is applicable to a predetermined wavelength of 300 to 45 Onm, and it is preferable to use a photoresist suitable for this. As shown in the above description, the use is as shown above. For the gray scale mask blank, the gray scale mask is manufactured according to the steps of FIG. 2 described above, thereby reducing the influence of the CD and semi-transmissive film on the mask on the surface reflectance of the variation, -19- 200925775 As a result, the CD of the reticle pattern can be correctly reproduced as a desired standard specification that can easily achieve the requirement of miniaturization of the pattern. Further, when the obtained gray scale mask is used to pattern transfer the transfer target, the influence of the scattered light caused by the reflection of the exposure light can be reduced. The transfer target 30 shown in Fig. 1 is patterned by using the above-described gray scale mask which can form a CD of a mask pattern with high precision obtained by the above embodiment and which can reduce the influence of scattered light during pattern transfer. By transfer, a high-precision transfer pattern (resist pattern 33) can be formed on the Λ-transferred body. The pattern shapes of the light shielding portion 21, the light transmitting portion 22, and the semi-light transmitting portion 23 shown in Figs. 1 and 2 are merely representative examples, and it is needless to say that the present invention is not limited thereto. (Second Embodiment) Fig. 3 is a cross-sectional view showing a manufacturing step of the gray scale mask of the embodiment. In the present embodiment, a case will be described in which a gray scale mask for manufacturing a TFT substrate including a light shielding portion, a light transmitting portion, and a semi-light transmitting portion is produced. Q, as shown in Fig. 3(a), the mask blank used is a light-shielding film 25 mainly composed of, for example, chromium Cr on a transparent substrate 24, and a resist is applied thereon to form a resist film 27. In this state, a semi-transmissive film is not formed. In the material of the light-shielding film 25, Si, W, A1 and the like are listed in addition to the material containing Cr as a main component. In the present embodiment, the transmittance of the light-shielding portion is determined by laminating the light-shielding film 25 and the semi-transmissive film 26 to be described later, and selecting the respective film materials and film thicknesses, and setting the optical density to 3 in total. · 0 or more. In the present embodiment, as described below, after the pattern of the light-shielding film 25 is formed, a semi-transmissive film is formed over the entire substrate including the light-shielding film -20-200925775. First, the first drawing is performed. In the case of the above resist, a positive resistance is used. Next, a predetermined pattern (a pattern of a resist pattern corresponding to a region of the light shielding portion and the light transmitting portion) is drawn on the resist film 27 on the light shielding film 25. After the drawing, development is performed to form a resist pattern 27 corresponding to the light shielding portion and the light transmitting portion (see Fig. 3(b)). Then, the resist pattern 27 is used as an etching mask, and the light-shielding moon is etched to form a light-shielding film pattern. When the film 25 containing chromium as a main component is used, it may be dry etching or wet etching by etching means, but in the present embodiment, wet etching is used. After the remaining resist pattern is removed (see FIG. 3 (the entire semi-transmissive film 26 is formed on the transparent substrate 24) (see FIG. 3(d)). The semi-transmissive film 26 has The transmission amount of the exposure light to the transparent 24 is about 10 to 80%, and the transmittance is preferably from 20 to 60%. In the present embodiment, the chromium oxide-containing chromic oxide is obtained by sputtering. The semi-transmissive film (the exposure light is 40%). Here, the light-shielding film 25 is the same as that of the first embodiment, and the measure for reducing the low surface reflectance can be applied. The surface reflectance of the light to be drawn is adjusted to be 45% or less. Next, the same resist film as the film film 27 is formed on the semi-transmissive film 26 of the gray-scale mask blank, and the semi-transmissive film 26 is formed on the semi-transmissive film 26 The resist film type light piece diagram and the like are relative to the 25th light-shielding c)) The light-film substrate has the second depiction by the over-current line and the above-mentioned type and the resistance - 21-200925775. In the second drawing, a predetermined pattern is drawn so that a resist pattern is formed on the light shielding portion and the semi-light transmission. After the drawing, development is performed to form a resist pattern 28 in a region corresponding to the light shielding portion and the semi-light transmitting portion (see Fig. 3(e)). The semi-transmissive film 26 is adjusted so that the surface reflectance of the light is 45% or less, so that the CD of the light-transmissive film 26 on the resist film drawn on the semi-transmissive film 26 can be reduced. The effect of surface reflectance. Here, the same drawing light as the above-described first drawing can be used as the drawing light. Next, the resist pattern 28 is used as an etching mask, and the exposed film of the light-transmissive film 26 and the light-shielding film 25 is etched to form a light-transmitting portion. In the case of the etching step at this time, in the present embodiment, wet etching is used. Then, the remaining resist pattern is removed, and the light-shielding portion 21 having the laminated film of the light-shielding film 25 and the semi-transmissive film 26, the light-transmitting portion 22 exposing the transparent substrate 24, and the half are completed on the transparent substrate 24 4 . A gray scale mask of the semi-transmissive portion 23 formed by the light-transmissive film 26 (see FIG. 3(f)). However, in the first and second embodiments described above, according to the review by the present inventors, the influence of the surface inversion rate of the drawing light on the line width CD in the mask used generally is as follows. . Fig. 4 shows the tendency of fluctuation in the line width CD of the surface reflectance. The drawing light used for the patterning described above is a case where laser light having a wavelength of 300 to 45 nm, for example, laser light having a wavelength of 413 nm is used. Fig. 4 shows the measurement results in the case of using a laser light having a wavelength of 43 6 nm which is similar to the above-described laser light. Fig. 4 shows the allowable range of reflectance when the laser is to be used, and the relationship between the reflectance and the line width is performed by the agent to trace the half of the upper surface of the eclipse. Results for 200925775.
具體而言，第4圖係顯示作爲描繪對象的光罩坯料的 表面反射率、及對其之圖案之CD的關係。在此係在Cr遮 光膜上塗佈阻劑，藉由雷射描繪進行實驗，但是亦可形成 爲其他材料的膜。隨著反射率的增加，所形成之圖案的CD 會有變粗的傾向。若由第4圖進行換算，可知以表面反射 率1%的變動，線寬係變動10nm。 φ 在薄膜電晶體製造用光罩中，係求取±0.35以m的CD 精度。因此，對曝光光之表面反射率的變動必須爲±35 %以 內。在具有更爲嚴謹之微細圖案的TFT製造用的通道部（ 例> 如通道部的寬度未達2/zm者等）中，由於求取±0.20 m 的CD精度，因此反射率變動係應該形成爲不會超過±20% 者。 此外，在既有之二元式光罩中，在Cr遮光膜上大部分 係形成有反射防止膜，其表面反射率爲10至15 %左右，因 Q 此藉由上述變動而所容許的最大反射率爲45 %以內，若爲 更爲微細的圖案，則爲30%以內。 在具有半透光膜的灰階光罩中，與遮光膜不同，由於 無法附加反射防止功能，因此有反射率上升的傾向，若按 其調整描繪光的照射條件（用量），即可在與Cr遮光膜相 同的CD精度中進行描繪。但是，在灰階光罩並存有具有 各種透過率的製品，關於該等，適用按照各自之反射特性 的描繪條件並沒有效率而且繁雜。因此發現即使將描繪條 件設爲一定，若使對描繪光的表面反射率與遮光膜的表面 -23- 200925775 反射率相同地形成爲45%以內’若爲具有更加微細圖案者 ，形成爲30 %以內，則可使所需的CD精度充足，而且在不 降低良率的情形下充足市場需求。 遮光膜、及半透光膜係可藉由濺鍍法等習知的手段來 形成。在本發明之灰階光罩坯料中，係將滿足上述表面反 射率的膜進行成膜，且檢查另外所成膜者並加以選擇’藉 此可僅使用具有充分之轉印精度的光罩坯料。半透光膜對 ▲ 描繪光的表面反射率係以不會超過45%的方式進行設計。 ❹ 其中，膜之表面反射率的下限係最好相對於曝光光爲10% 以上。此係基於有時會在曝光機（光罩對準器）上投入光 罩時，爲了檢測其存在或其位置，而使用照射在主表面之 光的反射光之故。如此一來，可使用已露出半透光膜的部 分，進行光罩的確認、位置確認。 爲了將表面反射率形成爲上述範圍內，可藉由因半透 光膜的組成所引起的折射率η、膜厚進行設計。此外，半 ρ 透光部係曝光光的透過率必須爲10至80%，以形成爲20 至60%的範圍內爲佳，因此可酌量該等參數，藉由習知的 膜設計方法進行設計。同樣地，可以將半透光膜對描繪光 之表面反射率在面內不會超過45 %的方式作調整。 例如，在半透光膜成膜時進行上述調整時，若使用濺 鍍法’可藉由調整濺鑛氣體的流量來進行。若爲CrOx的半 透光膜，係調整氧氣的流量，在COxNy中係僅調整氧及/ 或氮氣的流量，可使對描繪光之表面反射率不會超過45% -24- 200925775 此外，本發明之半透光膜係即使在其表面反射率稍微 變動（但是不會超過上述變動範圍），亦如上所述以不會 超過45%者爲佳。因此，必須檢查光罩坯料。在檢查表面 反射率時，係使用反射率測定器，在面內的複數個部位， 測定照射相當於描繪光之光時的表面反射率，使用經確認 使上述基準充足者。 第5圖係顯示上述第2實施形態所記載之使用氧化鉻 Λ 之半透光部之特性的圖。在此係顯示半透光部的曝光光透 〇 過率40%、描繪光表面反射率21.4 % (面內最大表面反射率 未達45%)之光罩坯料的線圖（profile)。 第5圖係顯示藉由濺鍍所得之成膜時間、藉由歐傑（ Auger )電子分光法所得之剖面組成（膜厚方向的組成）的 關係。由第5圖可知，濺鍍時間（歐傑分析時間）爲5分 鐘左右，到達藉由氧化鉻所形成的半透光部與藉由玻璃所 形成的透明基板的交界，以後屬於玻璃組成之成分的氧化 φ 矽會比形成半透光部的氧化鉻多。 使用由以上實施形態所得之精度佳地形成光罩圖案的 CD，而且可減低圖案轉印時之散射光的影響的上述灰階光 罩，對第1圖所示之被轉印體30進行圖案轉印，藉此可在 被轉印體上形成高精度的轉印圖案（阻劑圖案3 3 )。 如上所述，本發明之灰階光罩係極爲有效適用於薄膜 電晶體（TFT )製造用光罩。尤其通道部的線寬係隨著TFT 的動作高速化、小型化，有愈加變小的傾向，在如上所示 之情形下，必須進行描繪圖案之正確轉印之故。因此，顯 -25- 200925775 著呈現本發明的效果。 其中，本發明之灰階光罩並非僅爲具有一種半透光部 者’亦包括爲具有複數個曝光光透過率的多階（multitone )光罩的情形，此外亦包含供製造如上所示之光罩所用的 灰階光罩坯料。 【圖式簡單說明】 第1圖係用以說明使用灰階光罩之圖案轉印方法的剖 © 面圖。 第2圖係顯示本發明第1實施形態之灰階光罩之製造 步驟的剖面圖。 第3圖係顯示本發明第2實施形態之灰階光_之製造 步驟的剖面圖。 第4圖係顯示表面反射率與CD (線寬）之相關的曲線 圖。 第5圖係本發明第2實施形態所示之灰階光罩之半透 ❹ 光膜的線圖（profile)。 【主要元件符號說明】 20 灰 階 光 罩 21 遮 光 部 22 透 光 部 23 半 透 光 部 24 透 明 基 板 25 遮 光 膜 26 半 透 光 膜 -26- 200925775 27 阻劑膜 28 阻劑圖案 30 被轉印體 3 1 基板 32A 、 32B 膜 33 阻劑圖案Specifically, Fig. 4 shows the relationship between the surface reflectance of the mask blank to be drawn and the CD of the pattern. Here, a resist is applied to the Cr light-shielding film, and the experiment is carried out by laser drawing, but it may be formed into a film of another material. As the reflectance increases, the CD of the formed pattern tends to become thicker. When converted from Fig. 4, it was found that the line width was varied by 10 nm by a variation of the surface reflectance of 1%. φ In the reticle for manufacturing a thin film transistor, a CD accuracy of ±0.35 m is obtained. Therefore, the variation in the surface reflectance of the exposure light must be within ±35 %. In a channel portion for TFT fabrication having a more precise fine pattern (for example, if the width of the channel portion is less than 2/zm, etc.), since the CD accuracy of ±0.20 m is obtained, the reflectance variation should be It is formed to not exceed ±20%. Further, in the conventional binary reticle, an anti-reflection film is formed on most of the Cr light-shielding film, and the surface reflectance thereof is about 10 to 15%, which is the maximum allowable by the above variation. The reflectance is within 45%, and if it is a finer pattern, it is within 30%. In a gray scale mask having a semi-transmissive film, unlike the light-shielding film, since the reflection preventing function cannot be added, the reflectance tends to increase, and if the irradiation condition (amount of use) of the drawing light is adjusted, it is possible to The Cr light-shielding film is depicted in the same CD precision. However, in the gray scale mask, there are products having various transmittances, and it is not efficient and complicated to apply the drawing conditions in accordance with the respective reflection characteristics. Therefore, it is found that even if the drawing conditions are constant, the surface reflectance of the light to be drawn is set to be within 45% of the surface of the light-shielding film -23-200925775. If it is a finer pattern, it is formed within 30%. , which can make the required CD accuracy sufficient, and sufficient market demand without reducing the yield. The light-shielding film and the semi-transmissive film can be formed by a conventional means such as sputtering. In the gray-scale mask blank of the present invention, a film satisfying the above surface reflectance is formed into a film, and another film-former is inspected and selected, whereby only a mask blank having sufficient transfer precision can be used. . The semi-transmissive film is designed such that the surface reflectance of the light is not more than 45%. The lower limit of the surface reflectance of the film is preferably 10% or more with respect to the exposure light. This is based on the fact that when the reticle is placed on the exposure machine (mask aligner), the reflected light of the light irradiated on the main surface is used in order to detect the presence or position thereof. In this way, the portion where the semi-transmissive film is exposed can be used for confirmation and position confirmation of the mask. In order to form the surface reflectance within the above range, the refractive index η and the film thickness due to the composition of the semi-transmissive film can be designed. In addition, the transmittance of the exposure light of the half ρ light-transmitting portion must be 10 to 80%, preferably in the range of 20 to 60%, so that the parameters can be determined by the conventional film design method. . Similarly, the semi-transmissive film can be adjusted in such a manner that the surface reflectance of the drawn light does not exceed 45% in the plane. For example, when the above adjustment is performed at the time of film formation of the semi-transmissive film, the sputtering method can be used to adjust the flow rate of the splash gas. In the case of a semi-transmissive film of CrOx, the flow rate of oxygen is adjusted, and in the COxNy, only the flow rate of oxygen and/or nitrogen is adjusted, so that the surface reflectance of the light to be drawn does not exceed 45% -24-200925775 The semi-transmissive film of the invention preferably has a surface reflectance slightly (but does not exceed the above-described range of variation), and is preferably not more than 45% as described above. Therefore, the mask blank must be inspected. When the surface reflectance is inspected, the reflectance measuring device is used to measure the surface reflectance when the light corresponding to the drawing light is irradiated at a plurality of points in the plane, and it is confirmed that the above-mentioned standard is sufficient. Fig. 5 is a view showing the characteristics of the semi-transmissive portion using chromium oxide ruth described in the second embodiment. Here, a profile of the mask blank of the semi-transmissive portion having an exposure light transmittance of 40% and a light surface reflectance of 21.4% (the in-plane maximum surface reflectance of less than 45%) is displayed. Fig. 5 is a view showing the relationship between the film formation time by sputtering and the cross-sectional composition (composition in the film thickness direction) obtained by Auger electron spectroscopy. As can be seen from Fig. 5, the sputtering time (Oujie analysis time) is about 5 minutes, reaching the boundary between the semi-transmissive portion formed by chromium oxide and the transparent substrate formed by glass, and later belongs to the composition of the glass composition. The oxidized φ 矽 will be more than the chromia oxide forming the semi-transmissive portion. The transfer target 30 shown in Fig. 1 is patterned by using the above-described gray scale mask which can form a CD of a mask pattern with high precision obtained by the above embodiment and which can reduce the influence of scattered light during pattern transfer. Transferring, whereby a highly precise transfer pattern (resist pattern 3 3 ) can be formed on the transfer target. As described above, the gray scale mask of the present invention is extremely effective for use in a mask for manufacturing a thin film transistor (TFT). In particular, the line width of the channel portion tends to become smaller as the operation speed of the TFT is increased and the size is reduced. In the case as described above, it is necessary to perform accurate transfer of the drawing pattern. Therefore, the effect of the present invention is exhibited by -25-200925775. Wherein, the gray scale mask of the present invention is not only a case having a semi-transmissive portion but also includes a multi-tone mask having a plurality of exposure light transmittances, and is also included for manufacturing as shown above. Gray scale mask blank for the mask. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing a pattern transfer method using a gray scale mask. Fig. 2 is a cross-sectional view showing the steps of manufacturing the gray scale mask according to the first embodiment of the present invention. Fig. 3 is a cross-sectional view showing the manufacturing steps of the gray scale light according to the second embodiment of the present invention. Figure 4 is a graph showing the relationship between surface reflectance and CD (line width). Fig. 5 is a view showing a semi-transmissive film of a gray scale mask shown in the second embodiment of the present invention. [Main component symbol description] 20 Gray scale mask 21 Light blocking portion 22 Light transmitting portion 23 Semi-light transmitting portion 24 Transparent substrate 25 Light shielding film 26 Semi-transmissive film -26- 200925775 27 Resistive film 28 Resistive pattern 30 is transferred Body 3 1 substrate 32A, 32B film 33 resist pattern
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