200921266 九、發明說明： 【發明所屬之技術領域】 本發明係關於，在被轉印體上的光阻’利用光罩，形 成具有不同阻劑膜厚部分的轉印圖案的圖案轉印方法、該 圖案轉印方法中使用的灰階光罩及其製造方法° 【先前技術】 目前，在液晶顯示裝置（Liquid Crystal Display:以 下稱之爲LCD )的領域中，薄膜電晶體液晶顯示裝置（Thin200921266 IX. The invention relates to a pattern transfer method for forming a transfer pattern having portions of different resist film thicknesses by using a photomask on a resist on a transfer target, Gray-scale reticle used in the pattern transfer method and manufacturing method thereof [Prior Art] Currently, in the field of liquid crystal display (hereinafter referred to as LCD), a thin film transistor liquid crystal display device (Thin
Film Transistor Liquid Crystal Display _·以下稱之爲 TFT-LCD)相較於CRT (陰極線管），具有容易形成爲薄 型且消耗電力較低的優點，因此商品化目前正急速.發展 中。TFT-LCD係具有具備在配列成矩陣狀的各像素中配列 有TFT之構造的TFT基板及與各像素相對應，配列有紅、 綠及藍之像素圖案的彩色濾光片在介有液晶相之下方疊合 的槪略構造。TFT-LCD之製造步驟數很多，光是TFT基板 即使用了 5至6片光罩來製造。在如上所示之狀況下，藉 由使用具有遮光部、透光部及半透光部的光罩（稱爲灰階 光罩），以刪減在製造TFT基板時所利用的光罩片數的方 法已被提出（例如專利文獻1:日本特開2005-37933號公 報）。在此，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（殘膜値） 的部分。 在此’所謂灰階光罩係指具有：在透明基板上暴露的 200921266 透光部；在透明基板上形成有用以將曝光光遮光之遮光膜 的遮光部；及在透明基板上形成有遮光膜或半透光膜’而 將透明基板的光透過率設爲10 〇%時’使透過光量減低而使 預定量的光透過的半透光部（以下亦稱之爲灰階部）者。 以如上所示之灰階光罩而言’係以形成具有預定光透過率 之半透光膜者作爲半透光部者’或者在遮光膜或半透光膜 在曝光條件下形成解析界限以下之微細圖案者’或者形成 有具有預定光透過率的半透光膜者。 C第1圖係用以說明利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2 0係用以在被轉印體3 0上 - 形成膜厚呈階段性不同的阻劑圖案3 3.者。其中’在第1圖 ， 中，元件符號3 2 A、3 2 B係表示在被轉印體3 0中疊層在基 板3 1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;在 透明基板24表面上暴露且使曝光光透過的透光部22;及 I當將透光部2 2的曝光光透過率設爲1 〇 〇 %時’使透過率減 低爲10至80 %左右的半透光部23。第1圖所示之具半透 光部23係由形成在透明基板24上之具光半透過性的半透 光膜26所構成，但是亦可以當使用光罩時之曝光條件下超 過解析界限之微細圖案之形成而構成。遮光部21在此係在 半透光膜26上疊層遮光膜25而構成。 當使用如上所述之灰階光罩2 0時，在遮光部2 1曝光 光實質上不會透過，在半透光部23則係將曝光光減低。因 200921266 此，塗佈在被轉印體3 0上的阻劑膜（正型光阻膜）可以在 轉印後，經過顯影時，膜厚在與遮光部2 1相對應的部分變 厚’膜厚在與半透光部23相對應的部分變薄，在與透光部 22相對應的部分並不存在膜（實質上未產生殘膜）的方式， 形成膜厚呈階段性不同（亦即具有段差）的阻劑圖案3 3。 接著’在第1圖所示之阻劑圖案3 3之不存在膜的部 分’對被轉印體3 0中之例如膜3 2 A及3 2 B實施第1蝕刻， 藉由灰化（ashing )等將阻劑圖案33之膜厚較薄部分去除， 且在該部分’對被轉印體3 0中之例如膜3 2B實施第2蝕 刻。如此一來，使用1片灰階光罩2 0，在被轉印體3 0上 形成膜厚呈階段性不同的阻劑圖案3 3，藉此實施習知之光 罩2片份的步驟，而刪減光罩片數。 如上所示之光罩適用於製造顯示裝置，尤其液晶顯示 裝置的薄膜電晶體係極爲有效。例如，可藉由遮光部2 1形 成源極、汲極部，藉由半透光部2 3形成通道部。 【發明內容】 但是，一般在使用光罩而曝光在被轉印體時，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，而再次被照射在被轉印體，或曝光光 在曝光機內的任何部位中反射，其在光罩表面反射，而產 生照射在被轉印體上等的雜散光時，在被轉印體會產生非 本意的映入，而妨礙正確的圖案轉印。因此，在曝光機的 光學系統一般係會施行曝光時的雜散光對策。此外，在曝 200921266 光機係設有基準，例如光罩對曝光光的表面反射率若爲 1 0±5%，則可在不會有雜散光的影響的情形下進行轉印。 此外，在二元式光罩（binary mask)等光罩中，亦藉由施 行在作爲最上層的遮光膜設置反射防止膜等之反射防止措 施，而可使用十分充足使上述表面反射率1 5%以下之基準 的光罩。 另一方面，在被轉印體上形成具有膜厚呈階段性或連 續性不同的部分的阻劑圖案的目的之下，如上所述已知一 種灰階光罩係就圖案上的特定部位選擇性地減低曝光光的 透過率，而可控制曝光光之透過的光罩。在如此之灰階光 罩中，.已知在一種使曝光光之一部分透過的半透光部中使 用半透光膜。在該半透光部中使用半透光膜的灰階光罩 中’係形成在光罩的圖案構成，使該半透光膜在光罩的最 上層露出。該半透光膜基於在所希望的透過率範圍內透過 曝光光的必要性，無法適用直接層積如上述之二元式光罩 之類的反射防止膜。此外，在使用半透光膜的灰階光罩中， 亦有半透光部對曝光光的表面反射率係依其組成及膜厚， 無法避免超過1 0 %的情形。 相反地’使用如上所示之灰階光罩，在被轉印體進行 圖案轉印時’以被轉印體上之阻劑而言，相較於一般的二 元式光罩（亦即不存在半透光部）等光罩，使用敏感度的 曝光光量依存性較小、或顯影特性之曝光光量依存性較低 者’藉此較爲容易將阻劑的殘膜量控制在所希望的範圍 內。在如上所示之阻劑中，由於對該光量的光感度的變化 200921266 較小’因此使因曝光時之雜散光對圖案之映入的影響係比 較小。因此，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。 如上所述雖半透光膜對曝光光的表面反射率所造成之 雜散光的影響係小，但是表面反射率在製造灰階光罩的階 段中’對用於圖案化之描繪光極爲重要。原因是當藉由描 繪光’將圖案描繪在形成於半透光膜上的阻劑膜時，若半 透光膜表面的表面反射率過高時，無法正確地描繪圖案的 尺寸。 尤其在灰階光罩之製造步驟中，通常係必須進行2次 以上的描繪步驟。例如，爲了形成透光部、遮光部與半透 光部（在此係1種類之半透光部），必須對遮光膜與半透 光膜分別施行預定的圖案化，因此必須進行使用光阻的2 次微影步驟。使用具有2種以上之透過率的半透光膜的多 階（multi tone )光罩時，亦會有更加增加描繪次數的情形。 即使複數次描繪中的描繪能量（用量）爲相同，若作 爲描繪對象的膜的表面反射率不同，則會有在線寬（CD) 產生不均一之虞。例如，當半透光膜對描繪光的表面反射 率較大’則在對形成於半透光膜上的阻劑膜進行圖案描繪 時’容易在灰階光罩基底的阻劑膜內產生因描繪光而引起 的定波’因此’對表面反射率不同之膜的描繪在定波之產 生容易度產生差異’而在圖案的剖面形狀產生差異。此外， 當對灰階光罩基底進行圖案描繪時，當在阻劑膜及位於其 下層的半透光膜的界面中，描繪光的反射光量較大時，其 200921266 部位附近之阻劑的曝光量會變大，結果線寬會變大。在對 表面反射率不同之膜的描繪中，如上所示之影響的呈現方 式的程度亦不同。 因此，考慮按照膜的表面反射率，來變更描繪時的能 量。但是，在灰階光罩中，係按照其用途，求取各種透過 率者，因此其膜組成複雜，對於該等組成求取最適合之描 繪條件而設定描繪條件乃明顯繁雜而沒有效率。 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±0.35μιη以下作爲標 準規格，但是尤其在薄膜電晶體之通道部等部位中，對應 該圖案的微細化，使CD變動達成±0.20μιη左右乃係實質上 所需求的。尤其在薄膜電晶體製造用之灰階光罩中，在通 道部的線寬未達2 μ m的情形下，係需要如上所示之嚴謹的 規格。 本發明係鑑於上述習知的情形而硏創者，其目的爲首 先提供在製作灰階光罩時，可減低上述CD變動的灰階光 罩之製造方法及灰階光罩。 本發明之目的進一步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。 爲了解決上述課題，本發明係具有以下構成。 (構成1 ) 一種灰階光罩之製造方法，係具有透光部、遮光部及 使曝光光之一部分透過的半透光部的灰階光罩之製造方法 在該灰階光罩係依部位選擇性地減低曝光光對被轉印體的 -10- 200921266 照射量，在被轉印體上的光阻形成包含部分殘膜 所希望的轉印圖案，其特徵爲：在透明基板上依 有半透光膜與遮光膜的灰階光罩基底，在該灰階 施行第1圖案化，在包含經圖案化的遮光膜及所 透光膜的透明基板全面形成阻劑膜之後施行第2 藉此在該半透光膜與該遮光膜分別施行預定的圖 成爲灰階光罩，前述第1圖案化時之前述遮光膜 的表面反射率與前述第2圖案化時之前述半透光 光的表面反射率的差被調整爲3 5 %以下。 (構成2 ) 一種灰階光罩之製造方法，係具有透光部、 使曝光光之一部分透過的半透光部的灰階光罩 法，在該灰階光罩係依部位選擇性地減低曝光光 體的照射量，在被轉印體上的光阻形成包含部分 同的所希望的轉印圖案，其特徵爲：在透明基板 有遮光膜的灰階光罩基底施行第1圖案化，在包 化之遮光膜的透明基板全面形成半透光膜，在形 光膜之後施行第2圖案化，藉此在該半透光膜與 分別施行預定的圖案化而形成爲灰階光罩，前述 化時之前述遮光膜對描繪光的表面反射率與前述 化時之前述半透光膜對描繪光的表面反射率的差 3 5 %以下。 (構成3 ) 如構成1或2之灰階光罩之製造方法，其中 値不同的 序備妥具 光罩基底 露出的半 圖案化， 案化而形 對描繪光 膜對描繪 遮光部及 之製造方 對被轉印 殘膜値不 上將形成 含經圖案 成該半透 該遮光膜 第1圖案 第2圖案 被調整爲 ，前述第 -11- 200921266 1圖案化時之前述遮光膜對描繪光的表面反射率與前述第 2圖案化時之前述半透光膜對描繪光的表面反射率的差被 調整爲2 0 %以下。 (構成4 ) 如構成1至3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應使用前述灰階光罩時所適用的曝光 光的表面反射率爲1 〇 %以上的方式作調整。 (構成5 ) 如構成1至4中任一者之灰階光罩之製造方法，其中， 前述半透光膜之對前述第2圖案化時之描繪光的表面反射 率係以成爲4 5 %以下的方式作調整。 . (構成6 ) 如構成5之灰階光罩之製造方法，其中，前述半透光 膜之對前述第2圖案化時之描繪光的表面反射率係以成爲 3 0%以下的方式作調整。 (構成7 ) 如構成1至6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，對於阻 劑膜所使用的描繪光均爲具300nm至450nm之範圍內之預 定波長的光。 (構成8 ) 如構成1至7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所成者，或在膜厚方 向形成組成傾斜者。 -12- 200921266 (構成9 ) 如構成1至8中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36511111至43611111之範圍之預定區 域的曝光光所使用者。 (構成1 0 ) 一種灰階光罩’其特徵爲：藉由構成1至9中任一者 之灰階光罩之製造方法所製造。 (構成1 1 ) 如構成1 0之灰階光罩，其中，對於預定線寬的線寬偏 差爲±〇·35μηι以內。 (構成1 2 ) . 如構成1 1之灰階光罩，其中，對於預定線寬的線寬偏 差爲±0.20μηι以內。 (構成1 3 ) 一種圖案轉印方法，其特徵爲：具有使用藉由構成1 至9中任一者之製造方法所得之灰階光罩，或使用構成1 0 至1 2中任一者之灰階光罩，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部分之殘膜値不同的預定的 轉印阻劑圖案。 在本發明之灰階光罩之製造方法中，係在透明基板上 依序備妥具有半透光膜與遮光膜的灰階光罩基底，在該灰 階光罩基底施行第1圖案化，在包含經圖案化的遮光膜及 所露出的半透光膜的基板全面形成阻劑膜之後施行第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 200921266 化而形成爲灰階光罩，前述第1圖案化時之前述遮光膜對 描繪光的表面反射率與前述第2圖案化時之前述半透光膜 對描繪光的表面反射率的差被調整爲3 5 %以下。 此外，在本發明之灰階光罩之製造方法中，係在透明 基板上將形成有遮光膜的灰階光罩基底施行第1圖案化， 在包含經圖案化之遮光膜的透明基板全面形成半透光膜， 在形成該半透光膜之後施行第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， 前述第1圖案化時之前述遮光膜對描繪光的表面反射率與 前述第2圖案化時之前述半透光膜對描繪光的表面反射率 的差被調整爲35%以下。 藉此，可提高製作光罩時之第1與第2圖案化的線寬 精度，可滿足嚴謹的CD規格。 此外，使用所得的灰階光罩，對被轉印體進行圖案轉 印，藉此可提供線寬精度高的電子元件。 【實施方式】 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圖係顯示本發明第1實施形態之灰階光罩之製造 步驟的剖面圖。在第1實施形態中，係製作具備有遮光部、 透光部、及半透光部的TFT基板製造用灰階光罩。 第1實施形態所使用的灰階光罩基底係在透明基板24 上依序形成有：例如含有鉬矽化物的半透光膜2 6、及例如 以鉻C r爲主成分的遮光膜2 5，在其上塗佈阻劑而形成阻 -14- 200921266 劑膜2 7 (參照第2圖（a ))。以遮光膜2 5的材質而言， 除了上述以C r爲主成分的材料之外，列舉有s丨、w、A1 等。在第1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 . 〇以上。 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（短波長光）’但是在第1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 或3 5 5 nm等）。以上述阻劑而言係使用正型光阻。對於遮 光膜2 5上的阻劑膜2 7描繪預定的元件圖案（如在與遮光 部相對應的區域形成之阻劑圖案的圖案），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2 7 (參 照第2圖（b ))。 接著，將上述阻劑圖案2 7作爲蝕刻光罩，將遮光膜 2 5進行蝕刻而形成遮光膜圖案2 5，使半透光部及透光部頒 域上的半透光膜2 6露出。當使用以鉻爲主成分的遮光膜 2 5時，以蝕刻手段而言，可使用乾式鈾刻或濕式蝕刻之任 一者，但在第1實施形態中係利用濕式蝕刻。所殘留的阻 劑圖案係予以去除（參照第2圖（c ))。 接著，在包含上述遮光膜圖案25及所露出之半透光膜 2 6的基板上全面形成與前述相同的阻劑膜’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。描繪後，藉由進行顯影，在 與遮光部及半透光部相對應的區域上形成阻劑圖案28(參 200921266 照第2圖（d ))。 接著，將上述阻劑圖案2 8作爲蝕刻光罩而將所露出的 透光部區域上的半透光膜2 6進行蝕刻，而形成透光部（參 照第2圖（e ))。接著，將所殘留的阻劑圖案去除，完成 在透明基板24上具有由半透光膜26與遮光膜25的層積膜 所構成的遮光部21、露出透明基板24的透光部22及由半 透光膜2 6所構成的半透光部2 3的灰階光罩（參照第2圖 (f) ) ° 藉由以上之第1實施形態所得之可精度佳地形成光罩 圖案之線寬C D且可減低圖案轉印時之雜散光之影響的上 述灰階光罩，使用該灰階光罩對第1圖所示之被轉印體3 0 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 )。 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2 3的圖案形狀僅爲具代表性之一例，當然並非 將本發明限定於此。 如上所述，在第1實施形態中係使用在透明基板24上 依序具有半透光膜26及遮光膜25的灰階光罩基底（第2 圖（a))。上述灰階光罩基底（第2圖（a))中的半透 光膜26係具有曝光光對透明基板24之透過率爲10至80% 左右者，以形成且20至60%的透過率爲佳。 以上述半透光膜26之材質而言，係列舉鉻化合物、 Mo化合物、Si、W、A1等。以鉻化合物而言，係有氧化鉻 (CrOx)、氮化鉻（CrNx)、氮氧化鉻（CrOxN)、氟化 200921266 絡（CrFx)、或在g亥等含有碳或氯者，以]vio化合物而3 1 除了 MoSix以外，另外含有MoSi之氮化物、氧化物、氮 氧化物、碳化物等。此外，所形成之光罩上的半透光部2 3 的曝光光透過率係藉由上述半透光膜26的膜材質與膜厚 之選定而設定。在此係在第2圖（c)中，將半透光膜26 上的遮光膜2 5進行蝕刻，因此最好使半透光膜2 6與遮光 膜2 5具有對蝕刻劑的蝕刻選擇性較爲有利。因此，在半透 光膜2 6使用的素材係以Μ 〇化合物爲佳而採用Μ 〇 S i X (透 過率5 0 % )。 此外’遮光膜2 5的素材係採用以Cr爲主成分者。在 此’遮光膜2 5係以在膜厚方向之組成爲不同者爲佳。例如 可適用在由金屬鉻所構成的層上層積有氧化鉻（CrOx)者， 或在由金屬鉻所構成的層層積有氮氧化鉻（CrOxNy )者， 或在由氮化絡（C r N X )所構成的層層積有金屬銘、氧化鉻 (CrOx)者等。在此’層積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。藉由言周 整該組成及膜厚，可減低對描繪光的表面反射率。遮光膜 2 5對描繪光的表面反射率係可形成爲1 〇至1 5 % 。宜 中，以如上所示之遮光膜而言，亦可適用施行有·胃_ % % 之反射防止功能之周知的遮光膜。 在第1實施形態中，上述半透光膜26之_胃％ _ 26 對描繪光的表面反射率Rf26 ( % )相對於遮光膜25對描，繪 光的表面反射率 Rf25 ( % )，使其差爲 35%以下 (RF25-RF26^35% )。其中’在此適用的描繪光係可適用 200921266 300至450nm的預定波長，最好使用適合此條件的光阻。 此外，在此半透光膜2 6對描繪光的表面反射率係以在 面內爲4 5 %以下的方式作調整爲佳’以爲3 0 %以下的方式 作調整爲特佳。 使用如上所示之灰階光罩基底，按照上述第2圖的步 驟來製造灰階光罩，藉此使光罩上的圖案的CD不會因二 次描繪而過度地不均一，而可形成在容許範圍內。尤其在 包含微細圖案化的TFT通道部製造用光罩中’係使遮光膜 25對描繪光的表面反射率RF25與半透光膜26的表面反射 率 Rf26 的差爲 20°/。以下（RF25-RF26‘20%)爲佳。 藉此，可能地減低因膜對描繪光的反.射率的不同所造 成之CD變動的影響，其結果可將光罩圖案的CD正確重現 爲所希望値，而使圖案微細化之要求所對應預定的標準規 格之達成變得容易。此外，使用所得的灰階光罩而對被轉 印體進行圖案轉印時，亦可能地減低因曝光光的反射所造 成之雜散光的影響。 (第2實施形態） 第3圖係顯示第2實施形態之灰階光罩之製造步驟的 剖面圖。在第2實施形態中亦製作具備有遮光部、透光部、 及半透光部的TFT基板製造用灰階光罩。 所使用的光罩基底係在透明基板2 4上形成以例如鉻 C r爲主成分的遮光膜2 5 ’在其上塗佈阻劑而形成有阻劑膜 2 7 (參照第3圖（a ))。以遮光膜2 5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。在第 '18- 200921266 2實施形態中，遮光部的透過率係藉由層積上述遮光胃25 與後述的半透光膜而決定，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。 其中，在第2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型光 阻。接著，對阻劑膜27描繪預定的元件圖案（如形成與遮 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相對 應的阻劑圖案2 7 (參照第.3圖（b ))。 接著，以上述阻劑圖案2 7爲蝕刻光罩，將遮光膜2 5 進行蝕刻而形成遮光膜圖案。當使用以鉻爲主成分的遮光 膜2 5時，以蝕刻手段而言，可爲乾式蝕刻或濕式蝕刻之任 一者，但在第2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（c )) ’ 在透明基板24上之包含遮光膜圖案25的全面形成半透光 膜26(參照第3圖（d))。半透光膜26係具有對透明基 板24之曝光光之透過率爲10至80 %左右的透過率，以具 有2 0至6 0 %之透過率者爲更佳。在第2實施形態中係採用 藉由濺鍍成膜所得之含有氧化鉻的半透光膜（曝光光透過 率 4 0 % )。 在此，上述遮光膜2 5係與第1實施形態相同，可適用 施行有減低表面反射率之措施者。此外，上述半透光膜26 200921266 係以半透光膜2 6對描繪光的表面反射率R F 2 6 ( % )相對於 遮光膜25對描繪光的表面反射率RF25 ( % )之差爲35%以 下的方式作調整（Rf25-Rf26S35%)。此外，半透光膜26 對描繪光的表面反射率係以在面內爲4 5 %以下的方式作調 整。 接著，在上述灰階光罩基底的半透光膜26上形成與前 述相同的阻劑膜，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。在描繪後，藉由進行顯影，在與遮光部及半透光部 相對應的區域形成阻劑圖案2 8 (參照第3圖（e ))。其 中，在此之描繪光而百，係可使用與上述第1次描繪相同 者。 其中，在本發明中，當在上述第1次描繪與第2次描 繪時使用波長不同的描繪光時，上述遮光膜2 5對第1次描 繪所使用的描繪光的表面反射率與上述半透光膜26對第2 次描繪所使用的描繪光的表面反射率的差調整爲3 5 %以下 即可。 接著，以上述阻劑圖案2 8爲蝕刻光罩，將所露出的半 透光膜26與遮光膜25的層積膜進行蝕刻而形成透光部。 以此時的蝕刻手段而言，在第2實施形態中係利用濕式蝕 刻。接著，將殘留的阻劑圖案去除，完成在透明基板24上 具有由遮光膜25與半透光膜26的層積膜所構成的遮光部 21、露出透明基板24的透光部22、及由半透光膜26所構 成的半透光部2 3的灰階光罩（參照第2圖（。 -20 - 200921266 但是，在上述第1及第2實施形態中’藉由本發明人 的檢討，在一般所使用的光罩中’對描繪光的表面反射率 對線寬CD所造成的影響係如以下所示。 在第4圖顯示對應表面反射率之線寬CD的變動傾 向。以上述圖案化所使用之描繪光而言，係使用3 00至 4 5 Onm的雷射光，例如適用4 1 3 nm的波長。在第4圖中係 與其近似而使用4 3 6nm的波長。使用其波長，就表面反射 率的容許範圍，以表面反射率與線寬的關係進行驗證。 第4圖係顯示作爲描繪對象的光罩基底的表面反射率 與對應之圖案之CD的關係。在此係在藉由Cr所得的遮光 膜上塗佈阻劑’藉由雷射描繪進行實驗，但是該膜亦可以 其他材料形成。隨著表面反射率的增加，所形成之圖案的 C D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1 〇 n m。 在薄膜電晶體製造用光罩中，係求取CD精 度。因此’透過複數次的曝光步驟之對曝光光之表面反射 率的變動’必須爲±3 5 %以內。在具有更爲嚴謹之微細圖案 的TFT製造用的通道部中，由於求取±〇2〇_的CD精度， 因此表面反射率的變動係應該以不會超過土 2 〇 %者形成。 右使用未符合如上所示之要件的灰階光罩，會在藉由 第次與第一；人的微影步驟所得之c D產生變動，在第二 二人（對半；is光膜上之阻劑的描繪）時，會產生描繪能量變 得過大的傾向。 此外在既有之一兀式光罩中’由於由Cr所得之遮光 • 2 1 - 200921266 膜的表面反射率爲10至12 %左右，因此上述變動所容許的 最大反射率爲45 %以內’更爲嚴謹的規格爲3〇%以內。因 此，關於半透光膜，因表面反射率的變動所造成之最大的 表面反射率必須在45 %以內，更嚴謹而言必須在3〇%以內。 換言之，若使用如上所調整的半透光部的半透光膜，轉印 圖案的精度可成爲滿足市場需求者。 上述遮光膜及半透光膜係可藉由濺鍍法等周知的手段 而形成。 在本發明之灰階光罩基底中，係藉由將滿足上述表面 反射率的膜進行成膜’退一步檢查所成膜者，並加以選擇， 而可僅使用具有充分之轉印精度的光罩基底。半透光膜對 描繪光的表面反射率係以不會超過4 5 %的方式進行設計。 其中’膜之表面反射率的下限係最好相對於曝光光爲1〇% 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，而使用照射在膜之主表 面之光的反射光之故。藉此可使用已露出半透光膜的部 分，進行光罩的確認及位置確認。 爲了使表面反射率在上述範圍內，可對藉由因半透光 膜的組成所引起的折射率n及膜厚進行設計。此外，半透 光部之曝光光的透過率必須爲1 〇至8 0 %，2 0至6 0 %的範圍 內爲佳’因此可考量該等參數，藉由周知的膜設計方法而 進行設計。 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），亦以不會超過45% -22 - 200921266 者爲佳。因此，必須檢查光罩基底。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。 在第5圖顯示第2實施形態所記載之半透光部的曝光 光透過率 4 0 %、對描繪光的表面反射率 2 1 . 4 % (面內最大 表面反射率未達4 5 % )之光罩基底的實施例。第5圖係顯 示藉由濺鍍所得之成膜時間、藉由奧杰（Auger )電子分光 法所得之半透光膜的組成剖面（膜厚方向的組成）者。以 半透光膜而言，係使用氧化鉻。在此，遮光部對描繪光的 反射率爲1 3 %，因此遮光部與半透光部對描繪光的表面反 射率的差係未達1 〇 %，可提供良好的C D穩定性。 使用由以上實施形態所得，使用精度佳地形成光罩圖 案的CD，而且可減低圖案轉印時之雜散光的影響的上述灰 階光罩，對第1圖所示之被轉印體3 0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，本發明之灰階光罩適用於薄膜電晶體（TFT ) 製造用光罩係極爲有效。尤其通道部的線寬係隨著TFT的 動作高速化與小型化，有愈加變小的傾向，因此在如上所 示之情形下，有進行描繪圖案之正確轉印之必須。因此， 顯著地呈現本發明的效果。 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（multi tone ) 光罩者，更包含供如上所示之光罩之製造所用的灰階光罩 -23 - 200921266 基底。 【圖式簡單說明]Film Transistor Liquid Crystal Display (hereinafter referred to as TFT-LCD) has an advantage that it is easy to form thin and consumes less power than CRT (Cathode Wireline), and commercialization is currently in progress. The TFT-LCD has a TFT substrate having a structure in which TFTs are arranged in a matrix arranged in a matrix, and a color filter having a pixel pattern of red, green, and blue corresponding to each pixel is interposed with a liquid crystal phase. A schematic structure that is superimposed below it. The number of manufacturing steps of the TFT-LCD is many, and the TFT substrate is manufactured by using 5 to 6 masks. In the above-described situation, by using a photomask having a light shielding portion, a light transmitting portion, and a semi-light transmitting portion (referred to as a gray scale mask), the number of masks used in manufacturing the TFT substrate is reduced. A method has been proposed (for example, Patent Document 1: JP-A-2005-37933). Here, the semi-transmissive portion means that the transmittance of the transmitted exposure light is reduced by a predetermined amount when the pattern is transferred to the transfer target using a photomask to control the photoresist film on the transfer target. The portion of the residual film amount (residual film 値) after development. Here, the term "the so-called gray-scale mask" has a light-transmitting portion of 200921266 exposed on a transparent substrate; a light-shielding portion for forming a light-shielding film for shielding exposure light on the transparent substrate; and a light-shielding film formed on the transparent substrate In the semi-transmissive film, when the light transmittance of the transparent substrate is 10%, the semi-transmissive portion (hereinafter also referred to as a gray scale portion) that transmits a predetermined amount of light by reducing the amount of transmitted light is reduced. In the case of the gray scale mask shown above, 'to form a semi-transmissive film having a predetermined light transmittance as a semi-transmissive portion' or to form a resolution limit under exposure conditions under a light-shielding film or a semi-transmissive film The fine pattern is either formed with a semi-transmissive film having a predetermined light transmittance. C 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 3 having a different film thickness on the transfer target 30. In the first drawing, the reference numerals 3 2 A and 3 2 B indicate a film laminated on the substrate 31 in the transfer target 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 exposure light on the surface of the transparent substrate 24 The translucent portion 22 that passes through and the semi-transmissive portion 23 that reduces the transmittance to about 10 to 80% when the exposure light transmittance of the light transmitting portion 2 2 is 1%. The semi-transmissive portion 23 shown in Fig. 1 is composed of a semi-transmissive semi-transparent film 26 formed on a transparent substrate 24, but may exceed the resolution limit under exposure conditions when a photomask is used. The fine pattern is formed to form. The light shielding portion 21 is configured by laminating a light shielding film 25 on the semi-transmissive film 26. When the gray scale mask 20 as described above is used, the exposure light is not substantially transmitted through the light shielding portion 21, and the exposure light is reduced in the semi-light transmission portion 23. According to 200921266, the resist film (positive type resist film) coated on the transfer target 30 can be thickened in a portion corresponding to the light shielding portion 21 after development after transfer. The film thickness is thinner at a portion corresponding to the semi-transmissive portion 23, and a film (substantially no residual film is formed) is not present in a portion corresponding to the light transmitting portion 22, and the film thickness is different in stages (also That is, the resist pattern 33 has a step. Next, 'the portion where the film is absent in the resist pattern 3 3 shown in Fig. 1' performs the first etching on, for example, the films 3 2 A and 3 2 B in the transfer target 30, by ashing (ashing) The thin film portion of the resist pattern 33 is removed, and the second etching is performed on the film 3 2B in the portion to be transferred 30, for example. In this manner, by using one piece of the gray scale mask 20, a resist pattern 3 3 having a film thickness different in stages is formed on the transfer target 30, whereby the steps of the conventional mask 2 are performed, and Reduce the number of reticle pieces. The photomask shown above is suitable for use in the manufacture of display devices, and in particular, the thin film electro-crystal system of the liquid crystal display device is extremely effective. For example, the source and the drain are formed by the light shielding portion 21, and the channel portion is formed by the semi-light transmitting portion 23. SUMMARY OF THE INVENTION However, in general, when a photomask is used and exposed to a transfer target, it is necessary to take into consideration an adverse effect 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, is reflected on the surface of the reticle (pattern forming surface) or the back surface, and is again irradiated on the object to be transferred, or any portion of the exposure light in the exposure machine. The medium reflection, which is reflected on the surface of the reticle and generates stray light that is irradiated onto the object to be transferred, causes unintentional reflection on the object to be transferred, and prevents proper pattern transfer. Therefore, in the optical system of the exposure machine, countermeasures for stray light at the time of exposure are generally performed. In addition, in the exposure of 200921266, the optical system is provided with a reference. For example, if the surface reflectance of the mask to the exposure light is 10 ± 5%, the transfer can be performed without the influence of stray light. Further, in the photomask such as a binary mask, by performing reflection prevention measures such as providing an anti-reflection film or the like on the light-shielding film as the uppermost layer, it is possible to use the surface reflectance very well. The mask of the reference below %. On the other hand, under the purpose of forming a resist pattern having a portion having a film thickness different in stage or continuity on the transfer target, as described above, a gray-scale mask is known to select a specific portion on the pattern. The reticle that reduces the transmittance of the exposure light and controls the transmission of the exposure light. In such a gray scale reticle, it is known to use a semi-transmissive film in a semi-transmissive portion through which a part of exposure light is transmitted. A gray scale mask in which a semi-transmissive film is used in the semi-transmissive portion is formed in a pattern of a photomask, and the semi-transmissive film is exposed in the uppermost layer of the mask. The semi-transmissive film is not suitable for directly reflecting an antireflection film such as the above-described binary reticle based on the necessity of transmitting exposure light within a desired transmittance range. Further, in the gray scale mask using the semi-transmissive film, the surface reflectance of the semi-transmissive portion to the exposure light depends on the composition and the film thickness, and it is impossible to avoid exceeding 10%. Conversely, 'using the gray scale reticle as shown above, when pattern transfer is performed on the transfer target body', the resist on the transfer target is compared to the general binary reticle (ie, no If there is a mask such as a semi-transmissive portion, the amount of exposure light using sensitivity is small, or the amount of exposure light with development characteristics is low, which makes it easier to control the residual film amount of the resist to a desired level. Within the scope. In the resist as shown above, since the change in the light sensitivity to the amount of light is small, 200921266 is small, so that the influence of stray light on the reflection of the pattern upon exposure is small. Therefore, the inventors have found that the reflection characteristics in such a gray scale mask need to be reviewed from the viewpoint of being different from the above-described binary mask. As described above, although the effect of the semi-transmissive film on the stray light caused by the surface reflectance of the exposure light is small, the surface reflectance is extremely important in the stage of manufacturing the gray scale mask for the patterned light for patterning. The reason is that when the pattern is drawn on the resist film formed on the semi-transmissive film by drawing light, if the surface reflectance of the surface of the semi-transmissive film is too high, the size of the pattern cannot be accurately drawn. In particular, in the manufacturing steps of the gray scale mask, it is usually necessary to perform the drawing step twice or more. For example, in order to form a light-transmitting portion, a light-shielding portion, and a semi-transmissive portion (here, one type of semi-transmissive portion), it is necessary to perform predetermined patterning on the light-shielding film and the semi-transmissive film, respectively, and therefore it is necessary to use a photoresist. 2 lithography steps. When a multi-tone mask having a semi-transmissive film having two or more kinds of transmittances is used, the number of times of drawing can be further increased. Even if the drawing energy (amount) in the plurality of drawing is the same, if the surface reflectance of the film to be drawn is different, there is a possibility that the line width (CD) is uneven. For example, when the semi-transmissive film has a large surface reflectance for the light to be drawn, the pattern of the resist film formed on the semi-transmissive film is easily formed in the resist film of the gray scale mask substrate. The constant wave caused by the drawing of light "hences a difference in the ease of generation of a fixed wave with respect to the film having a different surface reflectance" and a difference in the cross-sectional shape of the pattern. In addition, when the gray scale mask substrate is patterned, when the amount of reflected light of the light is large in the interface between the resist film and the semi-transmissive film located under the layer, the exposure of the resist near the portion of 200921266 is exposed. The amount will become larger and the line width will become larger. In the depiction of films having different surface reflectances, the extent of the effects of the above-described effects is also different. Therefore, it is considered to change the energy at the time of drawing in accordance with the surface reflectance of the film. However, in the gray scale mask, various transmittances are obtained according to the use thereof, and therefore the film composition is complicated, and it is obviously complicated and inefficient to set the drawing conditions for the optimum drawing conditions for the compositions. 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 μm or less as a standard specification, but particularly in a channel portion such as a thin film transistor, Corresponding to the miniaturization of the pattern, the CD variation is approximately ±0.20 μm, which is substantially required. Especially in the gray scale mask for the manufacture of a thin film transistor, in the case where the line width of the channel portion is less than 2 μm, the strict specifications as shown above are required. The present invention has been made in view of the above-described circumstances, and its object is to provide a method of manufacturing a gray scale mask and a gray scale mask which can reduce the above-mentioned CD variation when fabricating a gray scale mask. Another object of the present invention is to provide a pattern transfer method capable of forming a high-precision transfer pattern on a transfer target using the gray scale mask as shown above. In order to solve the above problems, the present invention has the following constitution. (Configuration 1) 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 in a portion of the gray scale mask portion Selectively reducing the exposure amount of the exposure light to the -10 200921266 of the object to be transferred, and forming a desired transfer pattern containing a part of the residual film on the resist on the transfer target, which is characterized by: The gray scale mask base of the semi-transparent film and the light-shielding film is subjected to the first patterning in the gray scale, and the second borrowing is performed after the resist film is formed on the transparent substrate including the patterned light-shielding film and the light-transmissive film. In the semi-transmissive film and the light-shielding film, a predetermined pattern is used as a gray scale mask, and a surface reflectance of the light-shielding film at the time of the first patterning and a semi-transmissive light at the time of the second patterning are performed. The difference in surface reflectance is adjusted to be less than 35 %. (Configuration 2) A method of manufacturing a gray scale mask, which is a gray scale mask method having a light transmitting portion and a semi-transmissive portion that transmits a part of exposure light, and selectively reducing the gray scale mask portion The irradiation amount of the exposure light body forms a desired transfer pattern including the portion on the resist on the transfer target, and the first pattern is applied to the gray scale mask substrate having the light shielding film on the transparent substrate. A semi-transmissive film is formed on the transparent substrate of the packaged light-shielding film, and a second pattern is formed after the light-shielding film, whereby the semi-transmissive film is formed into a gray-scale mask by performing predetermined patterning, respectively. The difference between the surface reflectance of the light-shielding film for the drawing light and the surface reflectance of the semi-transmissive film to the drawing light at the time of the above-described formation is not more than 35 %. (Configuration 3) The method for manufacturing a gray scale mask of the first or second embodiment, wherein the different order of the mask is exposed to a semi-pattern of the mask base exposed, and the pattern is formed to form a light-shielding layer and the light-shielding portion is formed. The first pattern of the first pattern is adjusted so that the light-shielding film of the first pattern is adjusted so that the light-shielding film of the first pattern is adjusted when the pattern is formed by the -11-200921266 1 The difference between the surface reflectance and the surface reflectance of the semi-transmissive film to the drawing light at the time of the second patterning is adjusted to 20% or less. (Claim 4) The method for producing a gray scale mask according to any one of the above 1 to 3, wherein the semi-transmissive film has a surface reflectance of 1 for exposure light to which the gray scale mask is used. 〇% or more of the way to make adjustments. In a method of manufacturing a gray scale mask according to any one of the first to fourth aspect, the surface reflectance of the light of the semi-transmissive film to the second patterning is 45%. The following methods are adjusted. (Configuration 6) The method for producing a gray scale mask according to the fifth aspect, wherein the semi-transmissive film is adjusted so that the surface reflectance of the drawn light at the time of the second patterning is 30% or less . (Aspect 7) The method for producing a gray scale mask according to any one of the first to sixth aspect, 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 having a predetermined wavelength in the range of 300 nm to 450 nm. (Attachment 8) The method for producing a gray scale mask according to any one of the first to seventh aspect, 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. </ RTI> </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; . (Structure 10) A gray scale mask' is characterized in that it is manufactured by the method of manufacturing the gray scale mask of any one of 1 to 9. (Configuration 1 1) A gray scale mask constituting 10, wherein the line width deviation for a predetermined line width is within ±〇·35μηι. (Configuration 1 2) A gray scale mask constituting 1 1 in which the line width deviation for a predetermined line width is within ±0.20 μηι. (Configuration 1 3) A pattern transfer method characterized by having a gray scale mask obtained by the manufacturing method of any one of Compositions 1 to 9, or using any one of Compositions 10 to 12 In the gray scale mask, the exposure step of irradiating the exposure target with the exposure light forms a predetermined transfer resist pattern having a part of the residual film 在 on the transfer target. In the method for manufacturing a gray scale mask according to the present invention, a gray scale mask substrate having a semi-transmissive film and a light shielding film is sequentially prepared on a transparent substrate, and the first pattern is applied to the gray scale mask substrate. After the resist film is formed on the entire surface of the substrate including the patterned light-shielding film and the exposed semi-transmissive film, the second pattern is applied, whereby the semi-transmissive film and the light-shielding film are respectively subjected to a predetermined pattern 200921266. Formed as a gray scale mask, the difference between the surface reflectance of the light-shielding film for the drawing light and the surface reflectance of the semi-transmissive film for the drawing light at the time of the second patterning is adjusted to 3 Less than 5%. Further, in the method of manufacturing a gray scale mask of the present invention, the gray scale mask substrate on which the light shielding film is formed is first patterned on the transparent substrate, and the transparent substrate including the patterned light shielding film is formed entirely. The semi-transmissive film is subjected to the second patterning after the semi-transmissive film is formed, whereby the semi-transmissive film and the light-shielding film are respectively patterned by a predetermined pattern to form a gray scale mask, and the first patterning is performed. The difference between the surface reflectance of the light-shielding film for the drawing light and the surface reflectance of the semi-transmissive film for the drawing light in the second patterning is adjusted to be 35% or less. Thereby, the line width precision of the first and second patterning when the mask is produced can be improved, and the strict CD specification can be satisfied. Further, by using the obtained gray scale mask, the transfer target is patterned, whereby electronic components having high line width precision can be provided. [Embodiment] Hereinafter, the best mode for carrying out the invention will be described based on the drawings. (First Embodiment) FIG. 2 is a cross-sectional view showing a manufacturing step of a gray scale mask according to a first embodiment of the present invention. In the first 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 produced. In the gray scale mask base used in the first embodiment, a semi-transmissive film 26 containing molybdenum telluride, and a light-shielding film 25 having chromium Cr as a main component, for example, are sequentially formed on the transparent substrate 24. A resist is applied thereon to form a resist film - 2721 200921 film (see Fig. 2 (a)). The material of the light-shielding film 25 is exemplified by s丨, w, A1, and the like in addition to the above-mentioned material containing C r as a main component. In the first 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 optical density is set by selecting the respective film materials and film thicknesses. 3. 〇 Above. First, the first drawing is performed. In the drawing, most of the electron beams or light (short-wavelength light) are used. However, in the first embodiment, laser light (a predetermined wavelength in the range of 300 to 450 nm, for example, 413 nm or 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 (such as a pattern of a resist pattern formed in a region corresponding to the light-shielding portion), and development is performed after the drawing, thereby forming an area with the light-shielding portion. Corresponding resist pattern 2 7 (refer to Fig. 2(b)). Next, the resist pattern 27 is used as an etching mask, and the light-shielding film 25 is etched to form a light-shielding film pattern 25, and the semi-transmissive portion and the semi-transmissive film 26 on the light-transmitting portion are exposed. When a light-shielding film 25 containing chromium as a main component is used, either dry uranium etching or wet etching may be used as the etching means, but in the first embodiment, wet etching is used. The remaining resist pattern is removed (see Fig. 2(c)). Next, the same resist film as described above is entirely formed on the substrate including the light-shielding film pattern 25 and the exposed semi-transmissive film 26, and the second drawing is 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-light transmitting portion. After the drawing, the resist pattern 28 is formed on the region corresponding to the light shielding portion and the semi-light transmitting portion by development (refer to Fig. 2, Fig. 21, 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 exposed light-transmitting portion to form a light-transmitting portion (refer to Fig. 2(e)). Then, the remaining resist pattern is removed, and the light-shielding portion 21 including the laminated film of the semi-transmissive film 26 and the light-shielding film 25 on the transparent substrate 24, the light-transmitting portion 22 exposing the transparent substrate 24, and A gray scale mask of the semi-transmissive portion 23 formed of the semi-transmissive film 26 (see FIG. 2(f)) ° The line of the mask pattern can be accurately formed by the above-described first embodiment The gray scale mask which is wide CD and which can reduce the influence of stray light during pattern transfer, uses the gray scale mask to pattern transfer the transferred body 30 shown in FIG. 1 , thereby being A high-precision transfer pattern (resist pattern 3 3 ) is formed on the transfer 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 the present invention is not limited thereto. As described above, in the first embodiment, a gray scale mask base having a semi-transmissive film 26 and a light-shielding film 25 on the transparent substrate 24 is used (Fig. 2(a)). The semi-transmissive film 26 in the gray scale mask substrate (Fig. 2(a)) has a transmittance of exposure light to the transparent substrate 24 of about 10 to 80% to form a transmittance of 20 to 60%. It is better. The material of the semi-transmissive film 26 is a series of chromium compounds, Mo compounds, Si, W, A1, and the like. In the case of chromium compounds, there are chromium oxide (CrOx), chromium nitride (CrNx), chromium oxynitride (CrOxN), fluorinated 200921266 (CrFx), or carbon or chlorine in ghai, etc. In addition to MoSix, the compound 3 1 contains a nitride, an oxide, an oxynitride, a carbide, or the like of MoSi. Further, the exposure light transmittance of the semi-transmissive portion 2 3 on the formed photomask is set by the film material and film thickness of the semi-transmissive film 26. Here, in Fig. 2(c), the light-shielding film 25 on the semi-transmissive film 26 is etched, so that it is preferable to make the semi-transmissive film 26 and the light-shielding film 25 have etching selectivity to the etchant. More favorable. Therefore, the material used in the semi-transmissive film 26 is preferably Μ 〇 S i X (permeability 50%). Further, the material of the light-shielding film 25 is mainly composed of Cr. Here, the light-shielding film 25 is preferably different in composition in the film thickness direction. For example, it may be applied to a layer in which chromium oxide (CrOx) is laminated on a layer composed of metallic chromium, or in which a layer composed of metallic chromium is laminated with chromium oxynitride (CrOxNy), or in a nitrided network (Cr). NX) is made up of layers of metal, chromium oxide (CrOx). Here, the 'layering' may be a layer having a clear boundary, or a layer having a clear boundary without a clear boundary. By correcting the composition and film thickness, the surface reflectance to the depicted light can be reduced. The surface reflectance of the light-shielding film 25 to the light can be formed from 1 1 to 15%. In the case of the light-shielding film as described above, a well-known light-shielding film which performs the anti-reflection function of the stomach _%% can also be applied. In the first embodiment, the surface reflectance Rf26 (%) of the light of the semi-transmissive film 26 is opposite to the light-shielding film 25, and the surface reflectance Rf25 (%) of the light is drawn. The difference is 35% or less (RF25-RF26^35%). Wherein the light system to be applied here is applicable to a predetermined wavelength of 200921266 300 to 450 nm, and it is preferable to use a photoresist suitable for this condition. In addition, it is particularly preferable that the semi-transmissive film 26 adjusts the surface reflectance of the light to be adjusted to be preferably 5% or less in a plane of 5% or less. Using the gray scale mask substrate as described above, the gray scale mask is manufactured in accordance with the procedure of FIG. 2 described above, whereby the CD of the pattern on the mask is not excessively uneven due to the secondary drawing, and can be formed. Within the allowable range. In particular, in the photomask manufacturing TFT mask including the fine patterning, the difference between the surface reflectance RF25 of the light-shielding film 25 and the surface reflectance Rf26 of the semi-transmissive film 26 is 20°/. The following (RF25-RF26 '20%) is preferred. Thereby, it is possible to reduce the influence of the CD variation caused by the difference in the contrast ratio of the film to the depicted light, and as a result, the CD of the mask pattern can be correctly reproduced as a desired defect, and the pattern is required to be refined. The achievement of the corresponding predetermined standard specifications becomes easy. Further, when the transfer of the transferred body is carried out by using the obtained gray scale mask, it is possible to reduce the influence of stray light caused by the reflection of the exposure light. (Second Embodiment) Fig. 3 is a cross-sectional view showing a manufacturing procedure of a gray scale mask according to a second embodiment. In the second 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 also produced. The mask base used is formed on the transparent substrate 24 by a light-shielding film 25' having a chromium cr as a main component, and a resist film is formed thereon to form a resist film 27 (refer to Fig. 3 (a )). In the material of the light-shielding film 25, in addition to the material containing Cr as a main component, si, w, A1 and the like are listed. In the embodiment of the '18-200921266 2, the transmittance of the light-shielding portion is determined by laminating the light-shielding stomach 25 and a semi-transmissive film to be described later, and selecting the respective film materials and film thicknesses to set the total. The optical density is 3.0 or more. In the second embodiment, as described below, after the pattern of the light-shielding film 25 is formed, a semi-transmissive film is formed on the entire surface of the substrate including the light-shielding film pattern. First, the first drawing is performed. In the case of the above resist, a positive type resist is used. Next, the resist film 27 is drawn with a predetermined element pattern (e.g., a pattern of a resist pattern corresponding to a region of the light shielding portion and the light transmitting portion). After the drawing, development is performed to form a resist pattern 2 7 corresponding to the light shielding portion and the light transmitting portion (see Fig. 3(b)). Next, the resist pattern 27 is used as an etching mask, and the light shielding film 25 is etched to form a light shielding film pattern. When the light-shielding film 25 containing chromium as a main component is used, either the dry etching or the wet etching may be used as the etching means, but in the second embodiment, wet etching is used. After the remaining resist pattern is removed (see Fig. 3(c))', the semi-transmissive film 26 is formed on the transparent substrate 24 including the light-shielding film pattern 25 (see Fig. 3(d)). The semi-transmissive film 26 has a transmittance of about 10 to 80% to the exposure light of the transparent substrate 24, and more preferably has a transmittance of 20 to 60%. In the second embodiment, a semi-transmissive film containing chromium oxide (exposed light transmittance of 40%) obtained by sputtering and film formation is used. Here, the light-shielding film 25 is the same as that of the first embodiment, and a measure for reducing the surface reflectance can be applied. Further, the semi-transmissive film 26 200921266 is such that the difference between the surface reflectance RF 2 6 (%) of the light drawn by the semi-transmissive film 26 and the surface reflectance RF25 (%) of the light-shielding film 25 to the light is 35. The following adjustments are made in % (Rf25-Rf26S35%). Further, the semi-transmissive film 26 is adjusted so that the surface reflectance of the light is 45% or less in the plane. Next, a resist film similar to the above was formed on the semi-transmissive film 26 of the gray scale mask base, 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-light transmitting portion. After the drawing, the resist pattern 28 is formed in a region corresponding to the light shielding portion and the semi-light transmitting portion by development (see Fig. 3(e)). Here, the light is drawn here, and the same as the first drawing described above can be used. In the present invention, when the drawing light having a different wavelength is used in the first drawing and the second drawing, the surface reflectance of the light to be used for the first drawing by the light shielding film 25 and the half The difference in surface reflectance of the light to be used for the second drawing of the light-transmitting film 26 may be adjusted to 35 % or less. Next, the resist pattern 28 is used as an etching mask, and the exposed semi-transmissive film 26 and the laminated film of the light-shielding film 25 are etched to form a light-transmitting portion. In the second embodiment, the etching means is wet etching. Then, the remaining resist pattern is removed, and the light-shielding portion 21 including the laminated film of the light-shielding film 25 and the semi-transmissive film 26 on the transparent substrate 24, the light-transmitting portion 22 exposing the transparent substrate 24, and the like are completed. The gray scale mask of the semi-transmissive portion 23 formed by the semi-transmissive film 26 (refer to Fig. 2 (. -20 - 200921266, however, in the first and second embodiments described above), by review by the present inventors, In the mask used in general, the influence of the surface reflectance of the drawing light on the line width CD is as follows. Fig. 4 shows the tendency of the line width CD corresponding to the surface reflectance to change. For the depiction light used in the process, a laser light of 300 to 45 Onm is used, for example, a wavelength of 4 1 3 nm is applied. In Fig. 4, a wavelength of 4 3 6 nm is used similarly to the wavelength. The allowable range of the surface reflectance is verified by the relationship between the surface reflectance and the line width. Fig. 4 is a view showing the relationship between the surface reflectance of the mask base to be drawn and the CD of the corresponding pattern. Coating a resist on the light-shielding film obtained from Cr' by laser The experiment is carried out, but the film may be formed of other materials. As the surface reflectance increases, the CD of the formed pattern tends to become thicker. If converted from Fig. 4, it is known that the surface reflectance is 1%. The variation 'line width variation is 1 〇 nm. In the reticle for manufacturing a thin film transistor, the CD accuracy is obtained. Therefore, the variation of the surface reflectance of the exposure light through the plurality of exposure steps must be ±3 5 In the channel portion for TFT fabrication having a more rigorous fine pattern, since the CD accuracy of ±〇2〇_ is obtained, the variation of the surface reflectance should be formed by not exceeding 2% of the soil. The right-hand use of a gray-scale reticle that does not meet the requirements shown above will produce a change in c d obtained by the first and first; human lithography steps, in the second two (half; is light film) In the case of the above-mentioned resisting agent, there is a tendency that the drawing energy becomes too large. In addition, in one of the existing reticle reticles, the surface reflectance of the film is 10 to 10 due to the shading obtained by Cr. Around 12%, so the above changes allow The maximum reflectance is less than 45%. The more stringent specification is less than 3%. Therefore, for semi-transparent films, the maximum surface reflectance due to variations in surface reflectance must be within 45%, which is more rigorous. In other words, if the semi-transmissive film of the semi-transmissive portion adjusted as described above is used, the accuracy of the transfer pattern can be satisfied by the market demand. The above-mentioned light shielding film and semi-transmissive film can be used by It is formed by a known method such as a sputtering method. In the gray scale mask substrate of the present invention, a film formed by performing a film formation satisfying the above-mentioned surface reflectance is further examined and selected. Only a reticle substrate with sufficient transfer accuracy is 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 1% by weight or more based on the exposure light. This is based on the fact that when the reticle is placed on the exposure machine (mask aligner), in order to detect the presence or position thereof, the reflected light of the light irradiated on the main surface of the film is used. Thereby, the portion where the semi-transmissive film is exposed can be used for confirmation and position confirmation of the mask. In order to make the surface reflectance within the above range, the refractive index n 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 semi-transmissive portion must be from 1 8 to 80%, preferably in the range of 20 to 60%. Therefore, the parameters can be considered and designed by a well-known film design method. . Further, the semi-transmissive film of the present invention preferably has a surface reflectance slightly (but does not exceed the above-described range of variation), and is preferably not more than 45% -22 - 200921266. Therefore, the reticle base must be inspected. When the surface reflectance is inspected, the reflectance measuring device is used to measure the surface reflectance when the light is irradiated with light in a plurality of portions in the plane, and it is confirmed that the above reference is sufficient. Fig. 5 is a view showing the exposure light transmittance of the semi-transmissive portion according to the second embodiment of 40% and the surface reflectance of the drawn light of 21.4% (the maximum in-plane surface reflectance is less than 45%). An embodiment of a reticle base. Fig. 5 is a view showing a composition cross section (composition in the film thickness direction) of a semi-transmissive film obtained by Auger electron spectroscopy by a film formation time obtained by sputtering. In the case of a semi-transparent film, chromium oxide is used. Here, since the reflectance of the light-shielding portion with respect to the drawing light is 13%, the difference in the surface reflectance of the light-shielding portion and the semi-transmissive portion with respect to the drawing light is less than 1%, and good CD stability can be provided. The above-described embodiment is used, and the gray scale mask which forms the reticle pattern with high precision and which can reduce the influence of stray light at the time of pattern transfer is used, and the object to be transferred 3 shown in FIG. 1 is used. Pattern transfer is performed whereby a highly accurate 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 photomask manufacturing method for 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. Therefore, in the case as described above, it is necessary to perform accurate transfer of the drawing pattern. Therefore, the effects of the present invention are remarkably exhibited. Wherein, the gray scale mask of the present invention is not only a semi-transmissive portion, but also includes a multi-tone mask having a plurality of exposure light transmittances, and further includes a photomask as shown above. Grayscale reticle -23 - 200921266 substrate used in the manufacture. [Simple diagram]
κ. 第1圖係用以說明使用 面圖。 第 2 圖 係 顯 示 本 發 明 第 步驟 的 剖 面 圖 〇 第 3 圖 係 顯 示 本 發 明 第 步驟 的 剖 面 圖 0 第 4 圖 係 顯 示 表 面 反 射 圖。 第 5 圖 係 本 發 明 第 2 實 光膜 的 線 圖 ( pr 〇 f i 1 e ) 0 [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 27 阻 劑 膜 28 阻 劑 圖 案 30 被轉 印 體 3 1 基 板 灰階光罩之圖案轉印方法的剖 1實施形態之灰階光罩之製造 2實施形態之灰階光罩之製造 率與C D (線寬）之相關的曲線 施形態所示之灰.階光罩之半透 -24- 200921266κ. Figure 1 is used to illustrate the use of the surface. Fig. 2 shows a cross-sectional view of the first step of the present invention. Fig. 3 shows a cross-sectional view of the first step of the present invention. FIG. 4 shows a surface reflection map. Fig. 5 is a line diagram of the second real light film of the present invention (pr 〇 fi 1 e ) 0 [Description of main component symbols] 20 Gray scale mask 21 Light blocking portion 22 Light transmitting portion 23 Semi-light transmitting portion 24 Transparent substrate 25 Shading Film 26 Semi-transmissive film 27 Resist film 28 Resistive pattern 30 Transfer body 3 1 Pattern transfer method of substrate gray scale mask 1 Manufacture of gray scale mask 2 Gray scale light of embodiment The manufacturing rate of the mask is related to the CD (line width). The gray pattern of the mask is shown in the form of a half-through mask -24-21302266
32A、32B32A, 32B