1247965 玖、發明說明： 【發明所屬之技術領域】 本發明係關於適用於薄膜電晶體液晶顯示裝置（Th i η Film Transistor Liquid Crystal Display，以下稱 「TFT-LCD」）等之製造的灰階罩幕之製造方法。 【先前技術】 相較於CRT(陰極射線管），TFT-LCD因為具有容易形成 薄型且消耗電力較低的優點，故目前正急遽地朝商品化方 向進展。T F T - L C D具有在排列成矩陣狀的各像素上排列著 T F T之構造的T F T基板，以及對應各像素在隔著液晶相之 存在下重疊排列有紅、綠、及藍色像素圖案之彩色濾光器 之概略構造。TFT-LCD的製造步驟數偏多，僅TFT基板便 需使用5〜6片光罩進行製造。 在此種狀況下，便提案有使用4片光罩施行T F T基板之 製造的方法（例如下述專利文獻1、非專利文獻1 )。 此方法係藉由使用具有遮光部、透光部、及半透光部（灰 階部）的光罩（以下稱「灰階罩幕」），俾減少所使用罩幕的 片數。圖5與圖6 (圖6為接續圖5的製造步驟）所示係使 用灰階罩幕的TFT基板之製造步驟的一例。 在玻璃基板1上形成閘電極用金屬膜，並藉由使用光罩 的微影製程而形成閘電極2。其後，形成閘絕緣膜3、第1 半導體膜4(a-Si)、第2半導體膜5(N + a-Si)、源極汲極用 金屬膜6、及正型光阻膜7(圖5(1))。其次，採用具有遮 光部1 1、透光部1 2及半透光部1 3的灰階罩幕1 0，經由對 6 326\專利說明書(補件)\93-09\931 ] 8769 1247965 正型光阻膜7曝光、顯影，形成覆蓋著TFT通道部、源極 汲極形成區域、及資料線形成區域，且通道形成區域較薄 於源極汲極形成區域的第1阻蝕劑圖案7 a (圖5 ( 2 ))。其 次，以第1阻蝕劑圖案7 a為罩幕，對源極汲極用金屬膜6 及第2、第1半導體膜5、4施行蝕刻處理（圖5 ( 3 ))。其次， 藉由以氧施行的灰化（a s h i n g )，去除通道形成區域之較薄 的光阻膜，形成第2阻蝕劑圖案7 b (圖6 ( 1 ))。然後，以第 2阻蝕劑圖案7 b為罩幕，對源極汲極用金屬膜6進行蝕 刻，形成源極/汲極6 a、6 b，接著對第2半導體膜5進行 蝕刻（圖6 ( 2 ))，最後剝離殘存的第2阻蝕劑圖案7 b (圖 6(3))。 (專利文獻1 ) 日本專利特開2 0 0 0 - 1 1 1 9 5 8號公報 (非專利文獻1 ) 「月于1J F P D ·智能（FPD Intelligence)」， 1999 年 5 月， ρ· 3 卜 35 【發明内容】 (發明所欲解決之問題） 習知便有將欲以上述之灰階罩幕半色調曝光的部分作 成半穿透性半色調膜（半透光膜）的提案。藉由使用此半色 調膜，可減少半色調部分的曝光量並進行半色調曝光。 習知，半色調膜式的灰階罩幕係以如下方式進行製造。 在此舉出如圖7所示TFT基板的圖案1 0 0為例進行說明。 圖案1 0 0係由：由對應於T F T基板之源極與汲極的圖案 326\專利說明書(補件)\93-09\93118769 1247965 1 ◦ 1 a、1 Ο 1 b構成之遮光部1 Ο 1 ;由對應於T F T基板之通道 部的圖案構成之半透光部1 Ο 3 ;及形成於該等圖案周圍的 透光部1 0 2所構成。 首先，準備在透明基板上依序形成半透光膜與遮光膜的 罩幕链板（m a s k b 1 a n k )，並在此罩幕述板上形成阻#劑 膜。其次，施行圖案描繪，經由顯影，在對應於上述圖案 1 0 0的遮光部1 Ο 1與半透光部1 0 3的區域形成阻蝕劑圖 案。其次，藉由採用適當的方法進行蝕刻，去除對應於未 形成有上述阻鈔劑圖案的透光部1 0 2之區域的遮光膜、與 其下層的半透光層，形成如圖8(1)所示之圖案。即，形成 透光部202，同時形成對應於上述圖案100之遮光部與半 透光部之區域的遮光圖案2 0 1。在去除殘存之阻蝕劑圖案 之後，再度於基板上形成阻蝕劑膜，並施行圖案描繪，經 由顯影，在對應於上述圖案1 0 0之遮光部1 0 1之區域形成 阻蝕劑圖案。其次，藉由適當的蝕刻處理，僅去除未形成 有阻蝕劑圖案的半透光部區域的遮光膜。藉此，如圖8 ( 2 ) 所示，形成上述圖案1 0 0所對應的圖案。即，利用半透光 膜的圖案203而形成半透光部，同時形成遮光部的圖案 2 0 1a、2 01b ° 但是，若利用此種習知之罩幕製造方法，因為在第1次 的形成透光部之微影步驟與第2次的形成半透光部之微影 步驟中，分別施行圖案描繪，故除了描繪時間需花費2倍 以上之外，第2次的描繪必須施行對準（a 1 i g n m e n t)，俾不 與第1次之描繪間發生圖案偏差，但是即使提昇對準的精 8 326\專利說明書(補件)\93-09\93118769 1247965 度，實際上仍非常難以完全消除對準偏差。例如圖9 ( a)所 示，於因對準偏差而使半透光部的圖案2 0 3朝圖示X方向 偏移形成之情況，對應於T F T基板之源極/汲極之遮光部的 面積會不同於設計值，導致發生TFT特性改變的不良情 況。又，如圖9 ( b)所示，於因對準偏差而使半透光部的圖 案2 0 3朝圖示Y方向偏移形成之情況，將因T F T基板之源 極與汲極間的短路（s h 〇 r t)而發生不良情況。不管何種情 況，此種習知的罩幕製造方法，均難以精度佳地形成在TFT 中特別重要的通道部分。 又，在描繪時以曝光量1 0 0 %之光量描繪出透光部之後， 再以曝光量5 0 %左右的光量描繪出半透光部，藉以一次完 成描繪步驟的方法，在日本專利特開2 0 0 2 - 1 8 9 2 8 0號及日 本專利特開2 0 0 2 - 1 8 9 2 8 1號之各公報中均有揭示。 此方法亦因為描繪透光部用與半透光部用的2種資料， 故描繪時間需耗費2倍。此外，雖不致如上述隨施行二度 微影步驟而二度施行描繪步驟之情況所發生的對準偏差問 題，但是因為描繪2種資料，二度施行描繪，先描繪出描 繪區域之後，由於再一次從頭開始進行描繪，故無法避免 因所使用之描繪機本身的位置精度所造成之圖案對準偏差 的發生。所以，即便此種方法，相較於上述方法，即便偏 差量程度有些許差異，但是仍無法消除圖案偏差的問題。 所以，本發明之目的在於解決習知圖案偏差問題，提供 一種可製造高品質TFT的灰階罩幕之製造方法。 (供解決問題之手段） 9 326\專利說明書(補件)\93-09\93118769 1247965 為解決上述問題，本發明具有下述構造。 (構造1 ) 一種灰階罩幕之製造方法，係於具有遮光部、 透光部、及半透光部的灰階罩幕之製造方法中，其特徵為 包含有：準備在透明基板上依序至少形成有半透光膜及遮 光膜之罩幕埋板的步驟；在上述罩幕场板上形成阻姓劑膜 的步驟；對上述阻蝕劑膜，進行包括針對形成半透光部的 部分在該阻蝕劑膜上曝光成用以實施圖案曝光之曝光裝置 之解像極限以下的圖案之將阻蝕劑膜曝光的步驟；施行上 述阻蝕劑膜之顯影處理，形成在形成遮光部之部分與形成 半透光部之部分的阻蝕劑殘膜值不同之阻蝕劑圖案的步 驟；以上述阻蝕劑圖案作為罩幕，將遮光膜與半透光膜蝕 刻而形成透光部的步驟；僅去除上述半透光部上所殘存之 阻蝕劑圖案的步驟；以及以上述步驟中殘存之阻蝕劑圖案 作為罩幕，將遮光膜與半透光膜的積層膜之一部份蝕刻， 以形成半透光部的步驟。 (構造2 ) —種灰階罩幕之製造方法，係於薄膜電晶體基 板之製造步驟中所使用，且具有遮光部、透光部、及半透 光部，對應於上述薄膜電晶體基板的源極與汲極的圖案係 由上述遮光部所形成，而對應於通道部的圖案係由上述半 透光部所形成的灰階罩幕之製造方法中，其特徵為包含 有：準備在透明基板上依序至少形成有半透光膜及遮光膜 之罩幕坯板的步驟；在上述罩幕坯板上形成阻蝕劑膜的步 驟；對上述阻蝕劑膜，進行包括針對形成半透光部的部分 在該阻蝕劑膜上曝光成用以實施圖案曝光之曝光裝置之解 10 326\專利說明書(補件)\93-09\93118769 1247965 像極限以下的圖案之將阻蝕劑膜曝光的步驟；施行上述阻 蝕劑膜之顯影處理，形成在形成遮光部之部分與形成半透 光部之部分的阻蝕劑殘膜值不同之阻蝕劑圖案的步驟；以 上述阻蝕劑圖案作為罩幕，將遮光膜與半透光膜蝕刻而形 成透光部的步驟；僅去除上述半透光部上殘存之阻蝕劑圖 案的步驟；以及以上述步驟中殘存之阻蝕劑圖案作為罩 幕，將遮光膜與半透光膜的積層膜之一部份蝕刻，形成半 透光部的步驟。 (構造3)如構造1或2之灰階罩幕之製造方法，其中， 在上述罩幕坯板的半透光膜與遮光膜之間，設置用以在利 用蝕刻去除遮光膜之際保護半透光膜之緩衝膜。 (構造4 ) 一種灰階罩幕之製造方法，係於具有遮光部、 透光部、及半透光部的灰階罩幕之製造方法中，其特徵為 包含有：準備在透明基板上至少形成有穿透率具有膜厚依 存性之遮光膜之罩幕坯板的步驟；在上述罩幕坯板上形成 阻蝕劑膜的步驟；對上述阻蝕劑膜，進行包括針對形成半 透光部的部分在該阻蝕劑膜上曝光成用以實施圖案曝光之 曝光裝置之解像極限以下的圖案之將阻蝕劑膜曝光的步 驟；施行上述阻蝕劑膜之顯影處理，形成在形成遮光部之 部分與形成半透光部之部分的阻蝕劑殘膜值不同之阻蝕劑 圖案的步驟；以上述阻蝕劑圖案作為罩幕，將露出的遮光 膜蝕刻而形成透光部的步驟；僅去除上述半透光部上殘存 之阻蝕劑圖案的步驟；以及以上述步驟殘存之阻蝕劑圖案 作為罩幕，將露出的遮光膜蝕刻成可獲得既定之穿透率的 11 326\專利說明書(補件)\93-09\93118769 1247965 膜厚，以形成半透光部的步驟。 依照構造1，本發明的灰階罩幕之製造方法包含有：使 用在透明基板上依序至少形成有半透光膜及遮光膜之罩幕 坯板，對該罩幕坯板上所形成之阻蝕劑膜，進行包括針對 形成半透光部的部分在該阻蝕劑膜上曝光成用以實施圖案 曝光之曝光裝置之解像極限以下的圖案之將阻蝕劑膜曝光 的步驟；施行此阻蝕劑膜的顯影處理，形成在形成遮光部 之部分與形成半透光部之部分的阻蝕劑殘膜值不同之阻蝕 劑圖案的步驟；以該阻蝕劑圖案作為罩幕，將遮光膜與半 透光膜蝕刻，以形成透光部的步驟；以及僅去除半透光部 上殘存之阻蝕劑圖案，再以殘存之阻蝕劑圖案作為罩幕， 將遮光膜與半透光膜的積層膜之一部份蝕刻，形成半透光 部的步驟。 在本構造中，因為對罩幕坯板上所形成之如正型阻蝕劑 膜，針對形成半透光部的部分在該阻蝕劑膜上曝光成用以 實施圖案曝光之曝光裝置之解像極限以下的圖案，因此， 形成半透光部的部分係以較阻蝕劑完全感光之曝光量為少 的曝光量進行曝光，故而若施行影像處理，阻蝕劑便成為 以較薄之膜厚殘留的狀態。即，可獲得與對形成半透光部 的部分減少曝光量而予以曝光同樣的作用。所以，例如利 用透光部的描繪資料與用以於上述阻蝕劑膜上施行圖案曝 光之曝光裝置之解像極限以下的圖案所構成之半透光部描 繪資料的合成資料，施行一次描繪的話，便可經由顯影處 理而形成在形成遮光部之部分與形成半透光部之部分的阻 12 326\專利說明書(補件)\93-09\93118769 1247965 蝕劑殘膜值不同之阻蝕劑圖案。然後，以該阻蝕劑圖案作 為罩幕並蝕刻，形成透光部，且僅去除半透光部上殘存之 阻蝕劑圖案之後，再以殘存之阻蝕劑圖案作為罩幕，對遮 光膜蝕刻，形成半透光部。 如此，若依照本構造，因為可一次施行供灰階罩幕製作 用的描繪，因而可防止發生如習知般之第2 ‘次微影步驟之 描繪時的對準、或改變曝光量分別連續描繪2種描繪資料 的情況中受描繪機的位置精度而引起之偏差等影響導致品 質惡化的情況。所以，可充分確保罩幕的品質，因而特別 適用於對遮光部與半透光部間之位置精度、大小、尺寸等 要求較高圖案精度的灰階罩幕之製造。例如，特別適用於 T F T基板製造用之灰階罩幕的製造。又，因為可一次施行 描繪，因而僅要習知之二度施行描繪情況時的一半描繪時 間便可，在罩幕製作方面可縮短此部份所需的時間。 若依照構造2，以高品質製造在TFT基板之製造步驟中 所使用之對應於T F T基板的源極與汲極之圖案係由遮光部 所形成，而對應於源極與汲極間的通道部之圖案則由半透 光部所形成的灰階罩幕。為確保高品質之TFT特性，源極 與汲極間之通道部的圖案精度特別重要。若依照本構造之 方法，對應於源極與汲極之遮光部、及對應於此源極與汲 極間之通道部之半透光部可利用單次描繪進行製作，其位 置精度等可以單次描繪的精度保障。所以，可防止因習知 描繪時的對準偏差等之影響所造成之品質惡化，可確保要 求高圖案精度之TFT基板製造用灰階罩幕的充分品質。 13 326\專利說明書(補件)\93-09\93118769 1247965 若依照構造3，因為在上述罩幕坯板的半透光膜 膜之間，設置有在利用蝕刻去除遮光膜之際具有供 ϊ 透光膜用之所謂蝕刻終止功能的緩衝膜，故於以蝕 形成半透光部之部分之遮光膜時，可防止下層半透 生膜減少等損傷的情況。另外，緩衝膜為了能在構 光部的區域中不損及下層半透光膜的穿透率，通常 其去除，但是隨緩衝膜的材質，當屬於透明性較高 便未去除仍不損及半透光部之穿透性的情況，亦可 緩衝膜。 若依照構造4，本構造中所使用的罩幕坯板係透 上所設置的遮光膜，基本上為具有遮光性，且為隨 而穿透率特性有所不同的材質。即，當在透明基板 透率大概為0 %的膜厚形成遮光膜的情況，若形成半 的區域利用半蝕刻而將遮光膜膜厚變薄的話，便可 透光部所必需的約5 0 %穿透率。若依照本構造，如 構造1，可獲得圖案精度高的灰階罩幕，除此此外 所使用之灰階罩幕的層構造簡單，因而具有容易製 點。 【實施方式】 以下，利用實施形態詳細說明本發明。 圖1係顯示本發明之灰階罩幕之製造方法的第1 態，為依序圖示其製造步驟的概略剖視圖。 本實施形態中所使用的灰階罩幕，係如圖1 ( a )所 石英等透明基板21上，依序形成半透光膜22及遮 326\專利說明書(補件)\93-09\93118769 14 與遮光 保護半 刻除去 光膜發 成半透 最好將 、且即 殘留著 明基板 著膜厚 上以穿 透光部 獲得半 同上述 ，因為 造的優 實施形 示，在 光膜 1247965 23。其中，遮光膜23的材質最好為薄膜且可獲得較高遮光 性者，可舉例如：C r、S i、W、A 1等。又，半透光膜2 2材 質最好為薄膜，且當將透光部穿透率設為0 %時，可獲得穿 透率50%左右之半穿透性者，可舉例如：Cr化合物（Cr的氧 化物、氮化物、氮氧化物、氟化物等）、MoSi、Si、W、A1 等。S i、W、A 1等係隨其膜厚可獲得較高遮光性，或者可 獲得半穿透性的材質。又，所形成之遮罩的遮光部因為成 為半透光膜22與遮光膜23的積層，即便無法單獨以遮光 膜滿足遮光性，但是在配合半透光膜的情況可獲得遮光性 的話便可。另外，此處所謂「穿透率」係指相對於使用灰 階罩幕之如大型LCD用曝光機之曝光光波長的穿透率。 又，半透光膜之穿透率並不一定要限定在50 %左右。半透 光部之穿透性需設定於何種程度，係設計上的問題。 又，相關上述遮光膜23與半透光膜22的材質組合，最 好相互間膜的蝕刻特性不同，其中一膜在另一膜的蝕刻環 境中最好具有耐性。例如，遮光膜2 3由C r形成，而半透 光膜22由MoSi形成的情況，若將Cr遮光膜使用氯系氣體 予以乾式蝕刻，因為在與底層的MoS i半透光膜之間可獲得 較高的蝕刻選擇比，因此便可在幾乎不對MoSi半透光膜造 成損傷的情況下，藉由蝕刻而僅去除Cr遮光膜。此外，上 述遮光膜23與半透光膜22最好在基板上成膜之時呈密接 性良好狀態。 上述罩幕坯板可藉由在透明基板21上依序形成半透光 膜2 2與遮光膜2 3而獲得，成膜方法可採用如蒸鍍法、濺 15 326\專利說明書(補件)\93-09\93118769 1247965 鍍法、CVD (化學氣相沉積）法等，只要適當選擇適合膜種類 之方法的話便可。又，關於膜厚並無特別限制，只要能形 成可獲得良好之遮光性或半透光性之最佳化膜厚的話便 "vj" 〇 其次，針對使用此罩幕坯板的灰階罩幕之製造步驟進行 說明。 首先，在此罩幕坯板上塗布例如電子束用之正型阻蝕 劑，並施行烘烤而形成阻蝕劑膜2 4。 其次，採用電子束描繪機或雷射描繪機等施行描繪。描 繪圖案之一例係如圖2所示，具有遮光部3 1 a、3 1 b ;透光 部3 2 ;及半透光部（灰階部）3 3。其中，半透光部3 3係形 成有由所使用之描繪機解像極限以下之細微圖案（線路空 間（lineandspace))構成之遮光圖案33a的區域。當對應 於如上述圖7所示的TFT基板用圖案之情況，對應於源極 與汲極之圖案係由遮光部3 1 a、3 1 b形成，而對應於通道部 之圖案則由半透光部3 3形成。例如，雷射描繪機之解像極 限一般為2 . Ο μιη。因此，例如將圖2中的半透光部3 3之穿 透部33b之間隔寬度設定為未滿2. Ομπι，將遮光圖案33a 的線寬設定為低於描繪機解像極限以下的未滿2. 0 μιη。另 外，於線路空間圖案之情況，根據線寬設定於何種程度， 可調節當透過此圖案施行曝光時的曝光量，可控制最終形 成半透光部之部分的阻蝕劑之殘膜值。在本發明中，線寬 特別以設定為描繪機之解像最小線寬之約1 / 2〜1 / 3為佳。 採用具有此種遮光部31a、31b;透光部32;半透光部（灰 16 326\專利說明書(補件)\93-09\93118769 1247965 階部）3 3的圖案之描繪資料（於圖2之圖案之情況，最好例 如利用將透光部3 2之資料與半透光部3 3之資料合成的單 種資料），施行一次的描繪。此時的曝光量設定為形成透光 部區域之阻蝕劑可充分感光的曝光量。如此的話，形成透 光部的區域（圖1中所圖示的C區域）中，阻蝕劑可充份感 光，而形成遮光部之區域（圖1中所圖示的B區域）中，阻 蝕劑則呈未曝光（未被曝光）狀態。此外，形成半透光部的 區域（圖1中所圖示的A區域），因為上述遮光圖案33a並 無法利用描繪機予以解像，因此無法描繪出其線寬，整體 呈曝光量不足狀態。換句話說，半透光部可獲得如同減少 曝光量對阻蝕劑施行曝光的相同效果。 描繪後，若利用既定之顯影液予以顯影，便在罩幕坯板 上形成遮光部（B區域）與半透光部（A區域）處之阻蝕劑膜 殘膜值不同的阻蝕劑圖案2 4 a (參照圖1 ( b ))。因為在半透 光部的曝光量較少於阻蝕劑完全感光的曝光量，若施行顯 影的話將無法完全溶解，因而殘存較未曝光的遮光部之阻 蝕劑更薄的膜厚。另外，透光部則成為阻蝕劑完全被去除 的狀態。 其次，以所形成的阻蝕劑圖案2 4 a為罩幕，利用如乾式 蝕刻而去除透光部（C區域）中露出的遮光膜23與半透光膜 22，形成透光部（參照圖1(c))。於遮光膜23或半透光膜 2 2由CI·系材料構成之情況，可採用使用氯氣的乾式蝕刻。 其次，將以較薄膜厚殘留的半透光部（A區域）之阻蝕 劑，利用氧灰化等而完全去除（參照圖1 ( d))。此時，同時 17 326\專利說明書(補件)\93-09\93118769 1247965 亦削入遮光部（B區域）的阻蝕劑，而變成起初的一半左右 之膜厚。 其次，以殘存之阻蝕劑圖案2 4 a作為罩幕，利用如乾式 蝕刻去除半透光部（A區域）中露出的遮光膜23a，形成半透 光部（參照圖1 ( e))。此處，於遮光膜2 3與半透光膜2 2係 由#刻特性互異的材質所構成之情況，在對遮光膜施行钱 刻的環境中，半透光膜幾乎未被蝕刻，因而可避免半透光 膜發生減膜情況。依此，基本上最好使半透光部的遮光膜 完全被去除，但是於遮光膜2 3與半透光膜的蝕刻特性接近 的情況，即便為殘留著少許遮光膜蝕刻殘渣的狀態、或蝕 刻過度進行而使部分半透光膜遭去除的狀態，若未影響及 所獲得之半透光部之穿透特性的話均無妨。另外，最後所 殘存的阻蝕劑圖案係採用氧灰化等而去除。 依上述便完成本實施形態的灰階罩幕。所獲得之罩幕係 利用遮光膜的圖案23b而形成遮光部（Β區域），利用半透 光膜的圖案22a而形成半透光部（A區域），且其周圍露出 透明基板2 1而形成透光部（C區域）。依照本發明之方法， 因為可一次施行圖案的描繪，所以不致如習知般因圖案的 對準而發生偏差，可以高精度形成重要的圖案，因此可獲 得高品質的灰階罩幕。故，本發明頗適用於特別要求高圖 案精度的TFT基板製造用之灰階罩幕之製造。 另外，在上述實施形態中，供形成半透光部用的圖案， 並不限定於如圖2所示之遮光圖案3 3 a的線路空間圖案。 簡言之，例如藉由導入描繪機之解像極限以下的圖案並進 326\ 專利說明書(補件)\93-09\93118769 18 1247965 行描繪，可降低對形成半透光部之部分的阻钱劑所賦予的 曝光量並控制阻蝕劑殘膜值的話便可，所以圖案形狀並無 特別限制。因此，除線路空間圖案之外，亦可為如虛線、 網點（點陣）、方格圖樣等之圖案。 圖3所示係本發明灰階罩幕之製造方法的第2實施形 態，依序圖示其製造步驟的概略剖視圖。 本實施形態中所使用的罩幕坯板，如同圖（a)所示，係 在透明基板21上，依序形成半透光膜22、緩衝膜25及遮 光膜23。即，因為在半透光膜22與遮光膜23之間設置具 有蝕刻終止功能的緩衝膜2 5，因而在將形成有半透光部之 區域的遮光膜利用蝕刻而去除之際，可確實防止下層半透 光膜發生膜減少等損傷情況。故，因為設置緩衝膜，遮光 膜2 3與半透光膜2 2可由蝕刻特性相似的材質（例如相同材 料的膜、或主成分相同之材料的膜等）構成。另外，緩衝膜 的材質，係選自對蝕刻遮光膜2 3的環境具有耐性的材質。 此外，於需要去除半透光部之緩衝膜之情況，亦要求能在 乾式蝕刻等方法中不對底層的半透光膜22造成損傷地去 除的材質。緩衝膜可採用如Si〇2或SOG(Spin On Glass) 等。該等材質係當遮光膜由C r系材料構成之情況，在與遮 光膜之間可獲得較高蝕刻選擇比。此外，該等材質穿透性 良好，因為即便隔著半透光部仍未損及穿透特性，因而亦 可不要去除。 使用此種罩幕坯板製造灰階罩幕的方法係如同上述第1 實施形態。 19 326\專利說明書(補件)\93-09\93118769 1247965 即，首先在罩幕坯板上形成阻蝕劑膜2 4，並使用電子束 描繪機或雷射描繪機等施:行描繪。描繪圖案係如上述圖2 所示之具有遮光部31a、31b;透光部32;及半透光部（灰 階部）3 3，且半透光部3 3形成有由所使用之描繪機解像極 限以下之細微圖案的圖案，使用將該等合成的單種描繪資 料便可一次施行描繪。 描繪後，若利用既定顯影液對其施行顯影，便在罩幕坯 板上形成遮光部（B區域）與半透光部（A區域）處之阻蝕劑 膜殘膜值不同的阻蝕劑圖案2 4 a (參照圖3 ( b ))。因為在半 透光部的曝光量少於阻蝕劑完全感光的曝光量，因而若施 行顯影的話將無法完全溶解，而殘存較未曝光的遮光部之 阻#劑更薄的膜厚。 其次，以所形成的阻蝕劑圖案2 4 a作為罩幕，利用如乾 式蝕刻而去除透光部（C區域）中露出的遮光膜2 3、緩衝膜 2 5及半透光膜2 2，形成透光部（參照圖3 ( c ))。 其次，將以較薄之膜厚殘留的半透光部（A區域）之阻蝕 劑，利用氧灰化等而完全去除（參照圖3 ( d ))。 接著，以殘存之阻蝕劑圖案2 4 a為罩幕，利用如乾式蝕 刻而去除半透光部（A區域）中露出的遮光膜2 3 a與緩衝膜 2 5 a，形成半透光部（參照圖3 ( e ))。另外，因為設置緩衝 膜2 5，故在此之半透光部並未發生膜減少之情況。殘存之 阻蝕劑圖案係使用氧灰化等而去除。 依此，如圖3 ( e )所示，獲得由遮光膜圖案2 3 b構成的遮 光部、由半透光膜圖案22a構成之半透光部、及透光部分 20 326\專利說明書(補件)\93-09\93118769 1247965 別以高圖案精度形成的本實施形態之灰階罩幕。 另外，在本實施形態中，形成上述阻蝕劑圖案2 4 a之後， 亦可施行：（1)去除至遮光部的遮光膜23與緩衝膜25;(2) 去除半透光部的阻蝕劑；（3 )其次，同時施行半透光部之遮 光膜的蝕刻與透光部之半透光膜的蝕刻；（4 )最後去除半透 光部的緩衝膜。又，此情況，亦可同時施行（1 )的缓衝膜 2 5之去除及（2 )的阻蝕劑之去除。依照此種製造步驟的 話，整體可省略1至2個步驟數。 圖4所示係本發明灰階罩幕之製造方法的第3實施形 態，依序圖示其製造步驟的概略剖視圖。 本實施形態中所使用的罩幕坯板，如同圖（a)所示，係 在透明基板21上形成遮光膜23。藉此，將遮光膜膜厚利 用蝕刻處理形成部分不同狀態，膜厚較厚的部分為遮光 部，膜厚較薄的部分為半透光部。此情況的遮光膜2 3材質 並無特別限制，但是若為因遮光性偏高而將可獲得穿透率 大致為0 %的膜厚變薄之材質的話，在對其施行部分半蝕刻 而形成半透光部方面將較為困難。反之，若為因遮光性並 不太高而將可獲得穿透率大致為0 %之膜厚增厚之材質的 話，雖然比較容易施行半蝕刻，但是因為遮光部的圖案高 度較厚，圖案形狀與圖案精度有惡化之虞。所以，在本實 施形態中，遮光膜23最好選擇在1000〜2000A左右的膜厚 範圍内可獲得良好遮光性與半穿透性的材質。 採用此種罩幕坯板製造灰階罩幕的方法，乃如同上述第 1實施形態。 21 326\專利說明書(補件)\93-09\93118769 1247965 即，首先在罩幕坯板上形成阻蝕劑膜2 4，並使用電子束 描繪機或雷射描繪機等施行描繪。描繪圖案係如同上述實 施形態，為具有遮光部、透光部、及半透光部（灰階部）， 且半透光部形成有所使用之描繪機解像極限以下之細微圖 案的圖案，利用將該等合成的單種描繪資料便可一次施行 描繪。 描繪後，若利用既定之顯影液對其施行顯影，便在罩幕 坯板上形成遮光部（B區域）與半透光部（A區域）處之阻蝕 劑膜殘膜值不同的阻蝕劑圖案2 4 a (參照圖4 ( b ))。因為在 半透光部的曝光量較少於阻蝕劑完全感光的曝光量，故若 施行顯影的話無法完全溶解，而殘存較未曝光的遮光部之 阻蝕劑更薄的膜厚。 其次，以所形成的阻蝕劑圖案2 4 a作為罩幕，利用如乾 式蝕刻而去除透光部（C區域）露出的遮光膜23，形成透光 部（參照圖4 ( c ))。 其次，將以較薄膜厚殘留的半透光部（A區域）之阻蝕 劑，利用氧灰化等而完全去除（參照圖4 ( d ))。 接著，以殘存之阻蝕劑圖案2 4 a作為罩幕，對半透光部 (A區域）露出的遮光膜2 3 a施行半蝕刻，直到可獲得半透 光性的適當厚度，形成半透光部（參照圖4 ( e ))。 依此，如圖4 ( e )所示，可獲得由厚的遮光膜圖案所構成 的遮光部、由半蝕刻處理所形成之薄的遮光膜圖案所構成 的半透光部、及透光部分別以高圖案精度形成的本實施形 態之灰階罩幕。 22 326\專利說明書(補件)\93-09\93118769 1247965 在上述實施形態中，雖均針對採用正型阻蝕劑的V情況進 行說明，但是亦可採用負型阻蝕劑。此情況係以透光部成 為未曝光之方式，使用將遮光部資料與半透光部資料予以 合成的描繪資料進行描繪。描繪後，若施行顯影，便如同 上述實施形態，在罩幕坯板上形成遮光部與半透光部處的 阻蝕劑殘膜值不同的阻蝕劑圖案。因為在半透光部的曝光 量少於阻蝕劑完全感光的曝光量，因而成為未充分硬化的 狀態，若施行顯影，便以較完全感光並硬化的遮光部阻蝕 劑更薄的膜厚殘存。後續步驟則如同上述實施形態的情況。 (發明效果） 如上述所詳細說明，依照申請專利範圍第1項之發明， 本發明的灰階罩幕之製造方法因為可一次施行供灰階罩幕 製作用的描繪，因而可防止發生如習知之因第2次微影步 驟之描繪時的對準、或改變曝光量分別連續描繪2種描繪 資料的情況，受描繪機的位置精度而引起偏差等影響導致 品質惡化的情況。所以，可充分確保罩幕的品質，特別適 用於對遮光部與半透光部之位置精度、大小、尺寸等要求 高圖案精度的灰階罩幕之製造。又，因為可一次施行描繪， 故僅要習知之二度施行描繪情況時的一半描繪時間便可， 罩幕製作可縮短此部份所需的時間。 又，依照申請專利範圍第2項之發明，因為能精度佳地 形成用以確保高品質之TFT特性之特別重要的源極與汲極 間之通道部圖案，因而可確保要求高圖案精度之TFT基板 製造用灰階罩幕的充分品質。 23 326\專利說明書(補件)\93-09\93118769 1247965 又，依照申請專利範圍第3項之發明，因為在本發明所 使用之罩幕坯板的半透光膜與遮光膜之間設置有在利用蝕 刻去除遮光膜之際具有供保護半透光膜用之蝕刻終止功能 的緩衝膜，故遮光膜與半透光膜材質的選擇範圍較廣，可 獲得具備所需之半穿透特性的灰階罩幕。 又，依照申請專利範圍第4項之發明，使用在透明基板 上至少形成有遮光膜的罩幕坯板，與申請專利範圍第1項 之發明同樣地，可獲得圖案精度高的灰階罩幕，除此之外， 因為所使用之灰階罩幕的層構造簡單，因而具有容易製造 的優點。 【圖式簡單說明】 圖1 ( a )〜（e )為本發明第1實施形態的製造方法之步驟順 序的概略剖視圖。 圖2為包含半透光部曝光用細微圖案的描繪圖案之一例 圖。 圖3 ( a )〜（e )為本發明第2實施形態的製造方法之步驟順 序的概略剖視圖。 圖4 ( a )〜（e )為本發明第3實施形態的製造方法之步驟順 序的概略剖視圖。 圖5 ( 1 )〜（3 )為採用灰階罩幕的TFT基板之製造步驟的概 略剖視圖。 圖6 ( 1 )〜（3 )為採用灰階罩幕的TFT基板之製造步驟（接 續圖5製造步驟）的概略剖視圖。 圖7為TFT基板製造用罩幕圖案之一例圖。 24 326\專利說明書(補件)\93-09\93118769 1247965 圖8 ( 1 )、（ 2 }為說明習知灰階罩幕之製造方法的概略平 面圖。 圖9 ( a )、（ b )為說明因習知製造方法所發生灰階罩幕之 不良情況的概略平面圖。 (元件符號說明） 1 :玻璃基板 2 :閘極 3 :閘絕緣膜 4 :第1半導體膜 5 :第2半導體膜 6 :源極汲極用金屬膜 6a, 6b ：源極/汲極 7 :正型阻蝕劑膜 7 a :第1阻蝕劑圖案 7 b :第2阻蝕劑圖案 1 0 :灰階罩幕 1 1 , 3 1 a , 3 1 b，1 0 1 :遮光部 12,32,102,202：透光部 13,33,103：半透光部 21 :透明基板 22 :半透光膜 22a:半透光膜圖案 23, 23a:遮光膜 23b:遮光膜圖案 251247965 发明Invention Description: [Technical Field] The present invention relates to a gray scale cover which is applied to the manufacture of a thin film transistor liquid crystal display device (hereinafter referred to as "TFT-LCD"). The method of making the curtain. [Prior Art] Compared with CRTs (Cathode Ray Tubes), TFT-LCDs are rapidly evolving toward commercialization because of their advantages of being thin and easy to form. A TFT-LCD has a TFT substrate having a structure in which TFTs are arranged in a matrix arranged in a matrix, and color filters in which red, green, and blue pixel patterns are alternately arranged in correspondence with each pixel in the presence of a liquid crystal phase. The schematic structure of the device. The number of manufacturing steps of the TFT-LCD is relatively large, and only the TFT substrate needs to be manufactured using 5 to 6 photomasks. Under such circumstances, a method of manufacturing a TF T substrate using four masks has been proposed (for example, Patent Document 1 and Non-Patent Document 1 below). In this method, by using a photomask having a light-shielding portion, a light-transmitting portion, and a semi-transmissive portion (gray-scale portion) (hereinafter referred to as "gray-scale mask"), the number of masks to be used is reduced. Fig. 5 and Fig. 6 (Fig. 6 is a manufacturing step subsequent to Fig. 5) show an example of a manufacturing procedure of a TFT substrate using a gray scale mask. A metal film for a gate electrode is formed on the glass substrate 1, and the gate electrode 2 is formed by a lithography process using a photomask. Thereafter, the gate insulating film 3, the first semiconductor film 4 (a-Si), the second semiconductor film 5 (N + a-Si), the source-drain metal film 6, and the positive-type photoresist film 7 are formed ( Figure 5 (1)). Next, a gray-scale mask 10 having a light-shielding portion 1 1 , a light-transmitting portion 1 2 and a semi-transmissive portion 13 is used, via the pair 6 326 \ patent specification (supplement) \93-09\931 ] 8769 1247965 The resist film 7 is exposed and developed to form a first resist pattern 7 covering the TFT channel portion, the source drain forming region, and the data line forming region, and the channel forming region is thinner than the source drain forming region. a (Fig. 5 (2)). Then, the source drain metal film 6 and the second and first semiconductor films 5 and 4 are etched by using the first resist pattern 7 a as a mask (Fig. 5 (3)). Next, the thin resist film of the channel formation region is removed by ashing (a s h i n g) by oxygen to form a second resist pattern 7 b (Fig. 6 (1)). Then, the source/drain electrodes 6a and 6b are formed by etching the source/drain electrodes 6a and 6b with the second resist pattern 7b as a mask, and then the second semiconductor film 5 is etched (Fig. 6 (2)), finally, the remaining second corrosion inhibitor pattern 7b is peeled off (Fig. 6 (3)). (Patent Document 1) Japanese Patent Laid-Open Publication No. 2000- 1 1 1 9 5 (Non-Patent Document 1) "Monthly in 1J FPD · Intelligent (FPD Intelligence)", May 1999, ρ· 3 Bu 35. SUMMARY OF THE INVENTION (Problems to be Solved by the Invention) Conventionally, a portion to be exposed to a halftone of the gray scale mask described above has been proposed as a semi-transmissive halftone film (semi-transmissive film). By using this halftone film, the amount of exposure of the halftone portion can be reduced and halftone exposure can be performed. Conventionally, a halftone film type gray scale mask is manufactured in the following manner. Here, the pattern 100 of the TFT substrate shown in FIG. 7 will be described as an example. The pattern 1 0 0 is composed of a light-shielding portion 1 composed of a pattern 326 corresponding to a source and a drain of a TFT substrate, a patent specification (supplement), and a 1 1 a, 1 Ο 1 b 1; a semi-transmissive portion 1 Ο 3 composed of a pattern corresponding to a channel portion of the TFT substrate; and a light-transmitting portion 1 0 2 formed around the pattern. First, a mask chain plate (m a s k b 1 a n k ) of a semi-transparent film and a light-shielding film is sequentially formed on a transparent substrate, and a resist film is formed on the mask. Next, pattern drawing is performed, and a resist pattern is formed in a region corresponding to the light-shielding portion 1 Ο 1 and the semi-light-transmitting portion 1 0 3 of the pattern 100 by development. Next, by performing etching by an appropriate method, the light-shielding film corresponding to the region of the light-transmitting portion 1 0 2 in which the above-described banknote resist pattern is not formed, and the semi-transmissive layer of the lower layer thereof are removed, as shown in FIG. 8(1). The pattern shown. That is, the light transmitting portion 202 is formed, and at the same time, the light blocking pattern 2 0 1 corresponding to the region of the light shielding portion and the semi-light transmitting portion of the pattern 100 is formed. After the remaining resist pattern is removed, a resist film is formed on the substrate again, and patterning is performed, and a resist pattern is formed in a region corresponding to the light-shielding portion 1 0 1 of the pattern 100 by development. Next, only the light-shielding film of the semi-transmissive portion region in which the resist pattern is not formed is removed by an appropriate etching treatment. Thereby, as shown in FIG. 8 ( 2 ), the pattern corresponding to the pattern 1 0 0 is formed. In other words, the semi-transmissive portion is formed by the pattern 203 of the semi-transmissive film, and the patterns 2 0 1a and 2 01b of the light-shielding portion are formed. However, if the conventional mask manufacturing method is used, the first formation is performed. In the lithography step of the light transmitting portion and the lithography step of forming the semi-light transmitting portion in the second time, pattern drawing is performed, so that the drawing time must be doubled in addition to the drawing time, and the second drawing must be aligned ( a 1 ignment), 俾 does not have a pattern deviation from the first drawing, but even if the alignment is improved, it is still very difficult to completely eliminate the fine 8 326\patent specification (supplement)\93-09\93118769 1247965 degrees. Alignment deviation. For example, as shown in FIG. 9( a ), the pattern 2 0 3 of the semi-transmissive portion is formed to be shifted in the X direction due to the alignment deviation, and corresponds to the light shielding portion of the source/drain of the TFT substrate. The area will be different from the design value, resulting in a bad condition in which the TFT characteristics change. Further, as shown in FIG. 9(b), the pattern 2 0 3 of the semi-transmissive portion is formed to be shifted in the Y direction due to the alignment deviation, and is caused by the source and the drain of the TFT substrate. A short circuit (sh 〇rt) has occurred. In any case, such conventional mask manufacturing methods are difficult to accurately form a channel portion which is particularly important in the TFT. In addition, in the case of drawing, the light-transmitting portion is drawn with an amount of light of an exposure amount of 100%, and then the semi-transmissive portion is drawn with a light amount of about 50% of the exposure amount, thereby completing the drawing step once, in Japanese Patent It is disclosed in the publications of Japanese Patent Application Laid-Open No. Hei 2 0 0 2 - 1 8 9 2 8 1 . This method also draws two kinds of data for the light transmitting portion and the semi-light transmitting portion, so the drawing time is twice as long. In addition, although the problem of misalignment occurring in the case where the drawing step is performed twice as described above with the second lithography step is not caused, the two kinds of data are drawn, and the drawing is performed twice, after the drawing area is first drawn, Since the drawing is performed from the beginning, it is impossible to avoid occurrence of pattern misalignment due to the positional accuracy of the drawing machine itself used. Therefore, even with this method, even if the degree of the deviation is slightly different from the above method, the problem of pattern deviation cannot be eliminated. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve the problem of conventional pattern deviation and to provide a method of manufacturing a gray scale mask which can produce high quality TFTs. (Means for Solving the Problem) 9 326\Patent Specification (Supplement)\93-09\93118769 1247965 In order to solve the above problems, the present invention has the following configuration. (Structure 1) A method for manufacturing a gray scale mask is a method for manufacturing a gray scale mask having a light shielding portion, a light transmitting portion, and a semi-light transmitting portion, and is characterized by: preparing to be mounted on a transparent substrate a step of forming at least a mask of the semi-transparent film and the light-shielding film; forming a masking film on the mask field; and performing the method for forming the semi-transmissive portion on the resist film a step of exposing the resist film to a pattern below the resolution limit of the exposure device for performing pattern exposure, and performing a development process of the resist film to form a light shielding portion. a step of forming a resist pattern different from a residual resist value of the portion forming the semi-transmissive portion; and using the resist pattern as a mask to etch the light-shielding film and the semi-transparent film to form a light-transmitting portion a step of removing only the resist pattern remaining on the semi-transmissive portion; and using a resist pattern remaining in the above step as a mask to form a laminated film of the light-shielding film and the semi-transparent film Etching to form semi-transparent A step of. (Structure 2) A method for producing a gray scale mask, which is used in a manufacturing step of a thin film transistor substrate, and has a light shielding portion, a light transmitting portion, and a semi-light transmitting portion corresponding to the thin film transistor substrate The pattern of the source and the drain is formed by the light-shielding portion, and the pattern corresponding to the channel portion is a method for manufacturing the gray-scale mask formed by the semi-transmissive portion, and is characterized in that it is prepared to be transparent. a step of forming at least a semi-transparent film and a mask blank of the light-shielding film on the substrate; a step of forming a resist film on the mask blank; and performing the semi-transparent on the resist film A portion of the light portion is exposed on the resist film to form an exposure device for pattern exposure. 10 326\patent specification (supplement)\93-09\93118769 1247965 a pattern of a resist film below the limit a step of exposing; performing a development treatment of the above-mentioned resist film to form a resist pattern different from a residual resist value of a portion forming the light-shielding portion and a portion forming the semi-transmissive portion; and the above-mentioned corrosion inhibitor Pattern as a mask, will a step of etching the light film and the semi-transmissive film to form a light transmitting portion; removing only the resist pattern remaining on the semi-transmissive portion; and using the resist pattern remaining in the above step as a mask to shield the light One of the laminated film of the film and the semi-transmissive film is partially etched to form a semi-transmissive portion. (Construction 3) A method of manufacturing a gray scale mask according to Configuration 1 or 2, wherein between the semi-transmissive film of the mask blank and the light shielding film, a protective half is provided for removing the light shielding film by etching A buffer film for a light transmissive film. (Structure 4) A method for manufacturing a gray scale mask, which is characterized in that a method for manufacturing a gray scale mask having a light shielding portion, a light transmitting portion, and a semi-light transmitting portion is characterized in that it is prepared to be at least on a transparent substrate a step of forming a mask blank having a light-shielding film having a film thickness dependence; a step of forming a resist film on the mask blank; and performing a semi-transparent on the resist film a portion of the portion exposed to the resist film to expose the resist film to a pattern below the resolution limit of the exposure device for performing pattern exposure; performing development processing of the resist film described above to form a formation a step of forming a resist pattern different from a portion of the light-shielding portion and a residual resist value of the portion forming the semi-transmissive portion; and using the resist pattern as a mask to etch the exposed light-shielding film to form a light-transmitting portion a step of removing only the resist pattern remaining on the semi-transmissive portion; and using the resist pattern remaining in the above step as a mask to etch the exposed light-shielding film to obtain a predetermined transmittance of 11 326 \Patent Description Book (supplement) \93-09\93118769 1247965 Film thickness to form a semi-transmissive portion. According to the configuration 1, the method for manufacturing a gray scale mask of the present invention comprises: using a mask blank having at least a semi-transparent film and a light shielding film formed on the transparent substrate, and forming the mask blank a resist film comprising: a step of exposing the resist film to a pattern in which a portion of the semi-transmissive portion is exposed on the resist film to be below a resolution limit of an exposure device for performing pattern exposure; The development process of the resist film forms a step of forming a resist pattern different from a residual resist value of a portion forming the light-shielding portion and a portion forming the semi-transmissive portion; using the resist pattern as a mask a step of etching the light-shielding film and the semi-transmissive film to form a light-transmitting portion; and removing only the resist pattern remaining on the semi-transmissive portion, and using the remaining resist pattern as a mask, and the light-shielding film and the half One of the laminated films of the light-transmissive film is partially etched to form a semi-transmissive portion. In the present configuration, because a positive resist inhibitor film is formed on the mask blank, a portion for forming the semi-transmissive portion is exposed on the resist film to form an exposure device for performing pattern exposure. Like the pattern below the limit, therefore, the portion forming the semi-transmissive portion is exposed with an exposure amount that is less than the exposure amount of the complete resist of the resist, so that if the image processing is performed, the resist is formed into a thin film. Thick residual state. In other words, the same effect as that of exposing the portion where the semi-transmissive portion is formed by reducing the exposure amount can be obtained. Therefore, for example, by using the drawing data of the light transmitting portion and the synthetic material of the semi-transmissive portion drawing data formed by the pattern below the resolution limit of the exposure device for performing the pattern exposure on the resist film, the drawing is performed once. , a corrosion inhibitor having a different residual film value in the portion where the light shielding portion is formed and the portion where the semi-light transmitting portion is formed can be formed by the development processing, and the residual film value of the resist 12 326 \ patent specification (supplement) \93-09\93118769 1247965 pattern. Then, the resist pattern is used as a mask and etched to form a light-transmitting portion, and only the resist pattern remaining on the semi-transmissive portion is removed, and then the remaining resist pattern is used as a mask to the light-shielding film. Etching to form a semi-transmissive portion. As described above, according to the present configuration, since the drawing for producing the gray scale mask can be performed at one time, it is possible to prevent the alignment of the second 'second lithography step as conventionally known, or to change the exposure amount continuously. In the case of drawing two kinds of drawing materials, the quality is deteriorated due to the influence of the positional accuracy of the drawing machine or the like. Therefore, the quality of the mask can be sufficiently ensured, and therefore, it is particularly suitable for the manufacture of a gray scale mask which requires high pattern accuracy such as positional accuracy, size, and size between the light shielding portion and the semi-light transmission portion. For example, it is particularly suitable for the manufacture of gray scale masks for the manufacture of TF T substrates. Moreover, since the drawing can be performed at one time, it is only necessary to perform half of the drawing time when the drawing is performed twice, and the time required for the portion can be shortened in the mask making process. According to the structure 2, the pattern of the source and the drain corresponding to the TFT substrate used in the manufacturing process of the TFT substrate by the high quality is formed by the light shielding portion, and corresponds to the channel portion between the source and the drain. The pattern is a gray scale mask formed by a semi-transmissive portion. In order to ensure high-quality TFT characteristics, the pattern accuracy of the channel portion between the source and the drain is particularly important. According to the method of the present configuration, the light-shielding portion corresponding to the source and the drain and the semi-transmissive portion corresponding to the channel portion between the source and the drain can be fabricated by a single drawing, and the positional accuracy or the like can be single. The accuracy of the secondary depiction is guaranteed. Therefore, deterioration of quality due to influence of alignment deviation or the like at the time of conventional drawing can be prevented, and sufficient quality of a gray scale mask for TFT substrate manufacturing requiring high pattern accuracy can be secured. 13 326\Patent Specification (Repair)\93-09\93118769 1247965 According to the configuration 3, since the semi-transmissive film of the above-mentioned mask blank is provided with a supply for removing the light-shielding film by etching Since the light-transmissive film is a buffer film having an etching termination function, when a light-shielding film of a portion of the semi-transmissive portion is formed by etching, damage such as reduction of the lower semipermeable membrane can be prevented. In addition, the buffer film is usually removed in order to prevent the transmittance of the lower semi-transmissive film in the region of the light-shielding portion, but the material of the buffer film is not removed when it is high in transparency. In the case of the penetrability of the semi-transparent portion, the film may also be buffered. According to the structure 4, the mask blank used in the present structure is provided with a light-shielding film which is substantially opaque and has a different transmittance characteristic. In other words, when a light-shielding film is formed in a film thickness of a transparent substrate having a transmittance of about 0%, if the half-cut region is thinned by half etching, the light-transmissive portion is required to be about 50. % penetration rate. According to this configuration, as in the configuration 1, a gray scale mask having a high pattern accuracy can be obtained, and in addition, the layer structure of the gray scale mask used is simple, and thus it is easy to manufacture. [Embodiment] Hereinafter, the present invention will be described in detail by way of embodiments. Fig. 1 is a view showing a first embodiment of a method for producing a gray scale mask according to the present invention, and is a schematic cross-sectional view showing a manufacturing step thereof in order. The gray scale mask used in the embodiment is formed on the transparent substrate 21 such as quartz as shown in Fig. 1 (a), and the semi-transparent film 22 and the cover 326\patent specification (supplement)\93-09 are sequentially formed. 93118769 14 and the light-shielding protection, the removal of the light film is semi-transparent, and the film thickness of the bright substrate is left to penetrate the light portion to obtain the above-mentioned semi-identical, because of the excellent implementation of the shape, in the light film 1249965 twenty three. Among them, the material of the light-shielding film 23 is preferably a film and a high light-shielding property can be obtained, and examples thereof include C r , S i , W, and A 1 . Further, the material of the semi-transmissive film 2 2 is preferably a film, and when the transmittance of the light-transmitting portion is set to 0%, a semi-penetration having a transmittance of about 50% can be obtained, and for example, a Cr compound can be mentioned. (Cr, oxide, nitride, nitrogen oxide, fluoride, etc.), MoSi, Si, W, A1, and the like. S i, W, A 1 and the like can obtain a high light-shielding property depending on the film thickness thereof, or a material having a semi-transparent property can be obtained. Further, since the light-shielding portion of the mask formed is a layer of the semi-transmissive film 22 and the light-shielding film 23, even if the light-shielding property cannot be satisfied by the light-shielding film alone, the light-shielding property can be obtained when the semi-transmissive film is blended. . Further, the term "transmission rate" as used herein refers to the transmittance of the wavelength of the exposure light with respect to an exposure machine such as a large LCD using a gray scale mask. Further, the transmittance of the semi-transmissive film is not necessarily limited to about 50%. The degree of penetration of the semi-transmissive portion needs to be set, which is a design problem. Further, in combination with the material of the light-shielding film 23 and the semi-transmissive film 22, it is preferable that the etching characteristics of the film are different from each other, and one film is preferably resistant in the etching environment of the other film. For example, when the light-shielding film 23 is formed of Cr and the semi-transmissive film 22 is formed of MoSi, if the Cr light-shielding film is dry-etched using a chlorine-based gas, it may be between the underlying MoS i semi-transparent film. A higher etching selectivity is obtained, so that only the Cr light-shielding film can be removed by etching without causing damage to the MoSi semi-transmissive film. Further, it is preferable that the light shielding film 23 and the semi-transmissive film 22 are in a state of good adhesion when formed on the substrate. The mask blank can be obtained by sequentially forming the semi-transparent film 2 2 and the light-shielding film 23 on the transparent substrate 21. The film forming method can be performed by, for example, evaporation method, splashing 15 326\patent specification (supplement) \93-09\93118769 1247965 Plating, CVD (Chemical Vapor Deposition), etc., as long as the method suitable for the type of film is appropriately selected. Further, the film thickness is not particularly limited as long as it can form an optimum film thickness at which good light-shielding properties or semi-light transmittance can be obtained. "vj" Secondly, for the gray scale cover using the mask blank The manufacturing steps of the curtain are explained. First, a positive type resist such as an electron beam is applied to the mask blank, and baked to form a corrosion inhibitor film 24. Next, drawing is performed using an electron beam drawing machine or a laser drawing machine. An example of the drawing pattern is as shown in Fig. 2, and has a light shielding portion 3 1 a, 3 1 b , a light transmitting portion 3 2 , and a semi-light transmitting portion (gray portion) 33. Among them, the semi-transmissive portion 3 3 is formed with a region of the light-shielding pattern 33a composed of a fine pattern (line and space) below the resolution limit of the drawing machine used. In the case of the pattern for the TFT substrate as shown in FIG. 7, the pattern corresponding to the source and the drain is formed by the light shielding portions 3 1 a, 3 1 b, and the pattern corresponding to the channel portion is semipermeable. The light portion 3 3 is formed. For example, the laser rendering machine has a resolution limit of 2 . Ο μιη. Therefore, for example, the interval width of the penetrating portion 33b of the semi-transmissive portion 3 3 in Fig. 2 is set to be less than 2. Ομπι, set the line width of the light-shielding pattern 33a to be less than 2. below the resolution limit of the drawing machine. 0 μιη. Further, in the case of the line space pattern, depending on the degree to which the line width is set, the exposure amount when the exposure is performed through the pattern can be adjusted, and the residual film value of the corrosion inhibitor which finally forms part of the semi-light transmitting portion can be controlled. In the present invention, the line width is particularly preferably set to about 1 / 2 to 1 / 3 of the minimum line width of the resolution of the drawing machine. Drawing data having such a light-shielding portion 31a, 31b; a light-transmitting portion 32; a semi-transmissive portion (ash 16 326 \ patent specification (supplement) \93-09\93118769 1247965 step) 3 3 In the case of the pattern of 2, it is preferable to perform the drawing once, for example, by using a single type of data in which the data of the light transmitting portion 32 and the data of the semi-light transmitting portion 33 are combined. The exposure amount at this time is set to an exposure amount at which the corrosion-resistant agent forming the light-transmitting portion region can be sufficiently sensitized. In this case, in the region where the light transmitting portion is formed (the C region illustrated in FIG. 1), the resist can be sufficiently photosensitive, and the region where the light shielding portion is formed (the B region illustrated in FIG. 1) is blocked. The etchant is in an unexposed (not exposed) state. Further, in the region where the semi-transmissive portion is formed (the region A shown in Fig. 1), since the above-described light-shielding pattern 33a cannot be imaged by the drawing machine, the line width cannot be drawn, and the overall exposure amount is insufficient. In other words, the semi-transmissive portion can obtain the same effect as the exposure of the resist to reduce the amount of exposure. After the drawing, if a predetermined developing solution is used for development, a resist pattern having a different residual film value of the resist film at the light shielding portion (B region) and the semi-light transmitting portion (A region) is formed on the mask blank. 2 4 a (Refer to Figure 1 (b)). Since the exposure amount in the semi-transmissive portion is less than the exposure amount at which the resist is completely sensitized, if it is developed, it will not be completely dissolved, so that a thinner film thickness than the resist of the unexposed light-shielding portion remains. Further, the light transmitting portion is in a state in which the corrosion inhibitor is completely removed. Next, using the formed resist pattern 2 4 a as a mask, the light-shielding film 23 and the semi-transmissive film 22 exposed in the light-transmitting portion (C region) are removed by dry etching to form a light-transmitting portion (refer to the figure). 1(c)). In the case where the light-shielding film 23 or the semi-transmissive film 22 is composed of a CI-based material, dry etching using chlorine gas can be employed. Next, the corrosion inhibitor of the semi-transmissive portion (A region) remaining thicker than the film thickness is completely removed by oxygen ashing or the like (see Fig. 1 (d)). At this time, the 17 326\patent specification (supplement) \93-09\93118769 1247965 also cuts into the corrosion inhibitor of the light shielding portion (B area), and becomes the film thickness of about half of the original. Then, the semi-transmissive portion 23a exposed in the semi-transmissive portion (A region) is removed by dry etching using the remaining resist pattern 24a as a mask (see Fig. 1(e)). Here, in the case where the light-shielding film 23 and the semi-transmissive film 2 2 are made of a material having different engraving characteristics, the semi-transmissive film is hardly etched in an environment in which the light-shielding film is etched. It can avoid the film loss of the semi-transparent film. In this case, it is preferable that the light-shielding film of the semi-transmissive portion is completely removed. However, when the etching characteristics of the light-shielding film 23 and the semi-transmissive film are close to each other, even if a small amount of the light-shielding film is left in the etching residue, or The state in which the etching is excessively performed to remove a part of the semi-transmissive film may be carried out without affecting the penetration characteristics of the obtained semi-transmissive portion. Further, the last remaining resist pattern is removed by oxygen ashing or the like. The gray scale cover of this embodiment is completed as described above. The obtained mask is formed with a light-shielding portion (Β region) by the pattern 23b of the light-shielding film, and a semi-transmissive portion (A region) is formed by the pattern 22a of the semi-transmissive film, and the transparent substrate 2 1 is formed around the mask. Light transmitting portion (C area). According to the method of the present invention, since the drawing of the pattern can be performed at one time, the deviation of the pattern is not caused as is conventional, and an important pattern can be formed with high precision, so that a high-quality gray scale mask can be obtained. Therefore, the present invention is quite suitable for the manufacture of a gray scale mask for manufacturing a TFT substrate which is particularly required for high pattern accuracy. Further, in the above embodiment, the pattern for forming the semi-transmissive portion is not limited to the line space pattern of the light-shielding pattern 3 3 a as shown in Fig. 2 . In short, for example, by importing the pattern below the resolution limit of the drawing machine and drawing it into the 326\ patent specification (supplement)\93-09\93118769 18 1247965 line, the resistance to the part forming the semi-transmissive portion can be reduced. The amount of exposure imparted by the agent and the residual film value of the resist are controlled, so that the shape of the pattern is not particularly limited. Therefore, in addition to the line space pattern, it may be a pattern such as a broken line, a dot (dot matrix), a square pattern, or the like. Fig. 3 is a view showing a second embodiment of the method for producing a gray scale mask of the present invention, and a schematic sectional view showing the manufacturing steps thereof. In the mask blank used in the present embodiment, as shown in Fig. (a), the semi-transmissive film 22, the buffer film 25, and the light-shielding film 23 are sequentially formed on the transparent substrate 21. In other words, since the buffer film 25 having the etching termination function is provided between the semi-transmissive film 22 and the light shielding film 23, when the light shielding film in the region in which the semi-light-transmitting portion is formed is removed by etching, it can be surely prevented. The lower semi-transmissive film causes damage such as film reduction. Therefore, since the buffer film is provided, the light-shielding film 23 and the semi-transmissive film 2 2 can be made of a material having similar etching characteristics (for example, a film of the same material or a film of a material having the same main component). Further, the material of the buffer film is selected from materials which are resistant to the environment in which the light-shielding film 23 is etched. Further, in the case where it is necessary to remove the buffer film of the semi-transmissive portion, a material which can be removed without causing damage to the underlying semi-transmissive film 22 in a method such as dry etching is also required. The buffer film may be, for example, Si 2 or SOG (Spin On Glass). These materials are in the case where the light-shielding film is made of a Cr-based material, and a high etching selectivity ratio can be obtained between the light-shielding film and the light-shielding film. In addition, these materials have good penetrability because they do not need to be removed even if the penetrating properties are not impaired across the semi-transmissive portion. The method of manufacturing a gray scale curtain using such a curtain blank is as in the first embodiment described above. 19 326\Patent Specification (Supplement)\93-09\93118769 1247965 That is, first, a corrosion inhibitor film 24 is formed on the mask blank, and is drawn using an electron beam drawing machine or a laser drawing machine. The drawing pattern has the light shielding portions 31a and 31b, the light transmitting portion 32, and the semi-light transmitting portion (gray portion) 3 3 as shown in FIG. 2 described above, and the semi-light transmitting portion 33 is formed by the drawing machine used. The pattern of the fine pattern below the resolution limit can be rendered at one time using the single drawing data of the combination. After the drawing, if it is developed by a predetermined developer, a corrosion inhibitor having a different residual film value of the resist film at the light shielding portion (B region) and the semi-light transmitting portion (A region) is formed on the mask blank. Pattern 2 4 a (refer to Figure 3 (b)). Since the exposure amount in the semi-transmissive portion is less than the exposure amount at which the resist is completely sensitized, if it is developed, it will not be completely dissolved, and a film thickness smaller than that of the unexposed opaque portion will remain. Next, using the formed resist pattern 24 4 as a mask, the light-shielding film 23, the buffer film 25, and the semi-transmissive film 2 2 exposed in the light-transmitting portion (C region) are removed by dry etching, for example, A light transmitting portion is formed (refer to FIG. 3(c)). Next, the corrosion inhibitor of the semi-transmissive portion (A region) remaining in a thin film thickness is completely removed by oxygen ashing or the like (see Fig. 3 (d)). Next, using the remaining resist pattern 2 4 a as a mask, the light-shielding film 2 3 a and the buffer film 25 a exposed in the semi-transmissive portion (A region) are removed by dry etching to form a semi-transmissive portion. (Refer to Figure 3 (e)). Further, since the buffer film 25 is provided, no film reduction occurs in the semi-transmissive portion. The remaining resist pattern is removed by oxygen ashing or the like. Accordingly, as shown in FIG. 3(e), a light-shielding portion composed of the light-shielding film pattern 2 3 b, a semi-transmissive portion composed of the semi-transmissive film pattern 22a, and a light-transmitting portion 20 326\patent specification are obtained. ()) \93-09\93118769 1247965 The gray scale cover of this embodiment which is formed with high pattern accuracy. Further, in the present embodiment, after the resist pattern 2 4 a is formed, (1) the light-shielding film 23 and the buffer film 25 removed to the light-shielding portion may be performed; (2) the etching of the semi-transmissive portion is removed. (3) Next, etching of the light-shielding film of the semi-transmissive portion and etching of the semi-transmissive film of the light-transmitting portion are simultaneously performed; (4) finally removing the buffer film of the semi-transmissive portion. Further, in this case, the removal of the buffer film 25 of (1) and the removal of the corrosion inhibitor of (2) may be simultaneously performed. According to such a manufacturing step, 1 to 2 steps can be omitted as a whole. Fig. 4 is a view showing a third embodiment of the method for producing a gray scale mask of the present invention, and a schematic sectional view showing the manufacturing steps thereof. As shown in Fig. (a), the mask blank used in the present embodiment is formed with a light shielding film 23 on the transparent substrate 21. Thereby, the thickness of the light-shielding film is partially formed by etching, and the portion having a thick film thickness is a light-shielding portion, and the portion having a thin film thickness is a semi-light-transmitting portion. In this case, the material of the light-shielding film 23 is not particularly limited. However, if the film thickness is reduced to a thickness of approximately 0% due to the high light-shielding property, partial half-etching is performed thereon. The semi-transparent portion will be more difficult. On the other hand, if the material having a film thickness of about 0% is obtained because the light-shielding property is not too high, the half etching is relatively easy, but the pattern height of the light-shielding portion is thick. And the accuracy of the pattern has deteriorated. Therefore, in the present embodiment, it is preferable that the light-shielding film 23 is made of a material having good light-shielding property and semi-transparency in a film thickness range of about 1,000 to 2,000 Å. The method of manufacturing a gray scale curtain using such a curtain blank is as in the first embodiment described above. 21 326\Patent Specification (Supplement)\93-09\93118769 1247965 That is, first, a corrosion inhibitor film 24 is formed on the mask blank, and drawing is performed using an electron beam drawing machine or a laser drawing machine. The drawing pattern is a light-shielding portion, a light-transmitting portion, and a semi-transmissive portion (gray-scale portion) as in the above embodiment, and the semi-transmissive portion is formed with a pattern of a fine pattern having a resolution of the lower limit of the drawing machine used. The depiction can be performed at one time by using the single depiction data of the synthesis. After the drawing, if it is developed by a predetermined developer, the corrosion resistance of the resist film is different between the light shielding portion (B region) and the semi-light transmitting portion (A region) on the mask blank. The agent pattern 2 4 a (refer to Fig. 4 (b)). Since the exposure amount in the semi-transmissive portion is smaller than the exposure amount in which the resist is completely sensitized, if it is developed, it cannot be completely dissolved, and the film thickness of the resist of the unexposed light-shielding portion remains thinner. Then, the light-shielding film 23 exposed by the light-transmitting portion (C region) is removed by dry etching using the formed resist pattern 2 4 a as a mask to form a light-transmitting portion (see Fig. 4 (c)). Then, the corrosion inhibitor of the semi-transmissive portion (A region) remaining thicker than the film thickness is completely removed by oxygen ashing or the like (see Fig. 4 (d)). Next, using the remaining resist pattern 2 4 a as a mask, the light-shielding film 2 3 a exposed by the semi-transmissive portion (A region) is half-etched until a suitable thickness of semi-transparent is obtained to form a semi-transparent. Light section (refer to Figure 4 (e)). Accordingly, as shown in FIG. 4(e), a light-shielding portion composed of a thick light-shielding film pattern, a semi-transmissive portion composed of a thin light-shielding film pattern formed by a half etching process, and a light-transmitting portion can be obtained. The gray scale mask of this embodiment is not formed with high pattern accuracy. 22 326\Patent Specification (Supplement)\93-09\93118769 1247965 In the above embodiment, the description will be made with respect to the case of the V using a positive type resist, but a negative type resist may be used. In this case, the light-transmitting portion is unexposed, and the drawing data in which the light-shielding portion data and the semi-transmissive portion data are combined are used for drawing. After the drawing, if development is carried out, as in the above embodiment, a resist pattern having a different value of the residual resist of the resist at the light-shielding portion and the semi-transmissive portion is formed on the mask blank. Since the exposure amount in the semi-light-transmitting portion is less than the exposure amount in which the resist is completely sensitized, it is in an insufficiently hardened state, and if development is performed, the film thickness is thinner than the light-shielding portion resist which is more completely photosensitive and hardened. Remaining. The subsequent steps are as in the case of the above embodiment. (Effect of the Invention) As described in detail above, according to the invention of the first aspect of the patent application, the method for manufacturing a gray scale mask of the present invention can prevent the occurrence of habits because the drawing for the production of the gray scale mask can be performed at one time. It is known that the two types of drawing data are continuously drawn by the alignment at the time of drawing the second lithography step or by changing the exposure amount, and the quality is deteriorated due to the influence of variations such as the positional accuracy of the drawing machine. Therefore, the quality of the mask can be sufficiently ensured, and it is particularly suitable for the manufacture of a gray scale mask which requires high pattern accuracy such as positional accuracy, size, and size of the light shielding portion and the semi-light transmission portion. Moreover, since the drawing can be performed at one time, it is only necessary to perform half of the drawing time when the drawing is performed twice, and the mask making can shorten the time required for this part. Further, according to the invention of claim 2, since the channel portion pattern between the source and the drain which is particularly important for ensuring high-quality TFT characteristics can be formed with high precision, TFTs requiring high pattern accuracy can be secured. The full quality of the gray scale mask for substrate manufacturing. 23 326\Patent specification (supplement)\93-09\93118769 1247965 Further, according to the invention of claim 3, the semi-transparent film and the light-shielding film of the mask blank used in the present invention are provided. There is a buffer film for protecting the semi-transparent film from etching when the light-shielding film is removed by etching, so that the material of the light-shielding film and the semi-transmissive film can be selected in a wide range, and the desired semi-transparent property can be obtained. Grayscale cover. Further, according to the invention of claim 4, a mask blank having at least a light-shielding film formed on a transparent substrate is used, and a gray scale mask having high pattern accuracy can be obtained in the same manner as the invention of claim 1 In addition, since the layer structure of the gray scale mask used is simple, it has an advantage of being easy to manufacture. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 (a) to (e) are schematic cross-sectional views showing the steps of a manufacturing method according to a first embodiment of the present invention. Fig. 2 is a view showing an example of a drawing pattern including a fine pattern for exposure of a semi-transmissive portion. Fig. 3 (a) to (e) are schematic cross-sectional views showing the steps of the manufacturing method of the second embodiment of the present invention. 4(a) to 4(e) are schematic cross-sectional views showing the steps of the manufacturing method of the third embodiment of the present invention. Fig. 5 (1) to (3) are schematic cross-sectional views showing the manufacturing steps of the TFT substrate using the gray scale mask. Fig. 6 (1) to (3) are schematic cross-sectional views showing the manufacturing steps of the TFT substrate using the gray scale mask (the manufacturing step of Fig. 5). Fig. 7 is a view showing an example of a mask pattern for manufacturing a TFT substrate. 24 326\Patent specification (supplement)\93-09\93118769 1247965 Figure 8 (1), (2) is a schematic plan view illustrating the manufacturing method of the conventional gray-scale mask. Figure 9 (a), (b) is A schematic plan view showing the problem of the gray scale mask caused by the conventional manufacturing method. (Explanation of the component symbols) 1: Glass substrate 2: Gate 3: Gate insulating film 4: First semiconductor film 5: Second semiconductor film 6: Metal film for source bungee 6a, 6b: source/drain 7: positive type resist film 7 a : first resist pattern 7 b : second resist pattern 1 0 : gray scale mask 1 1 , 3 1 a , 3 1 b, 1 0 1 : light shielding portion 12, 32, 102, 202: light transmitting portion 13, 33, 103: semi-light transmitting portion 21: transparent substrate 22: semi-transmissive film 22a: semi-transmissive film pattern 23, 23a: light shielding film 23b: light shielding film pattern 25
326\專利說明書(補件)\93-09\931 ] 8769 1247965 2 4 :阻蝕劑膜 24a :阻蝕劑圖案 25,25a：緩衝膜 33a, 201 ：遮光圖案 3 3 b :穿透部 1 0 0 : T F T基板用圖案 1 0 1 a，1 0 1 b ··圖案 201 a, 20 1 b :圖案 203:半透光膜用圖案 26 326\專利說明書(補件)\93-09\93118769326\Patent specification (supplement)\93-09\931] 8769 1247965 2 4 : corrosion inhibitor film 24a: corrosion inhibitor pattern 25, 25a: buffer film 33a, 201: light shielding pattern 3 3 b : penetration portion 1 0 0 : pattern for TFT substrate 1 0 1 a, 1 0 1 b · pattern 201 a, 20 1 b : pattern 203: pattern for semi-transparent film 26 326\patent specification (supplement)\93-09\93118769