1244671 玖、發明說明： 【發明所屬之技術領域】 本發明係關於製造液晶顯示裝置用薄膜電晶體基 用的灰階罩幕之灰階部的缺陷檢查方法。 【先前技術】 薄膜電晶體液晶顯示裝置（以下，稱為TFT-LCD) 比較，因其容易薄型化且消耗電力低的優點，現在 化的進程正快速發展中。T F T - L C D具有在液晶相介 重疊在排列為矩陣狀之各像素排列有TFT之構造的 板，及對應各像素排列有紅（R )、綠（G )及藍（B )的像 的彩色濾光器的大致構造。T F T - L C D中，製造步驟 僅僅TF T基板就要使用5〜6枚光罩進行製造。 在如此之狀況下，提出有一種使用4牧光罩進行 板的製造的方法（例如，非專利文獻1、專利文獻] 該方法係藉由使用具有遮光部、透光部及灰階部 (以下，稱為灰階罩幕），以減低使用之罩幕數。圖 使用灰階罩幕之TFT基板的製造步驟的一例。 在玻璃基板1上形成有閘極用金屬膜，藉由使用 光刻製程形成閘極2。其後，形成閘極絕緣膜3、第 體膜4 ( a - S i :非晶質矽）、第2半導體膜5 (摻N+非晶 源極汲極用金屬膜6及光阻膜7 (圖3 ( 1 ))。其次， 用灰階罩幕8曝光、顯像處理正型光阻，形成TFT 及源極汲極形成區域，與覆蓋資料線形成區域並且 形成區域形成為較源極汲極形成區域薄的第1光阻 312/發明說明書(補件)/93-06/93109051 板等 ，與 CRT 其商品 入之下 TFT基 素圖案 數多， TFT基 .)° 的光罩 3顯示 光罩之 1半導 質矽）、 藉由使 電路部 電路部 圖案 5 1244671 7 a (圖3 ( 2 ))。接著，以第1光阻圖案7 a作為光罩，蝕刻 處理源極汲極用金屬膜6及第1、第2半導體膜4、5(圖 3(3))。接著，藉由以氧氣使灰化（ashing)除去電路部形成 區域之薄光阻膜，形成第2光阻圖案7 b (圖4 ( 1 ))。然後， 以第2光阻圖案7 b作為光罩，蝕刻處理源極汲極用金屬膜 6形成源極/汲極6 a、6 b，接著，蝕刻處理第2半導體膜 5 (圖4 ( 2 ))，最後剝離殘留之第2光阻圖案7 b (圖4 ( 3 ))。 作為在此所使用之灰階罩幕8，如圖5所示，具有對應 源極/汲極之遮光部1 1 a、1 1 b ;透光部1 2及對應電路部之 灰階部1 3。灰階部1 3係為形成使用灰階罩幕之大型L C D 用曝光機的析像界限以下的遮光圖案1 3 a的區域。遮光部 1 1 a、1 1 b與遮光圖案1 3 a通常均係由鉻或鉻化合物等的相 同材料組成的相同膜厚的膜所形成。使用灰階罩幕之大型 LCD用曝光機的析像界限，在步進（stepper)方式的曝光機 約為3 // m，在鏡面投影方式的曝光機約為4 // m。因此，例 如在圖5，將灰階部之透過部1 3 b的空間幅度設為未滿3 // m，將曝光機的析像界限以下的遮光圖案1 3 a的線寬設為 未滿 3 // m。 但是，如上述之灰階罩幕之灰階部，因不容易進行微細 圖案加工、或受發生於製造步驟中的灰塵等大大的影響等 的理由，將發生遮光圖案1 3 a的細、粗等的C D故障或多餘 圖案或缺失圖案形成的圖案缺陷等（以下，稱圖案太粗或多 餘圖案缺陷等為黑缺陷，稱圖案太細或缺失圖案缺陷等為 白缺陷）。 6 312/發明說明書(補件)/93-06/93109051 1244671 在此，針對超過允許範圍之上述缺陷，雖施以圖案修 正，但因為灰階部之圖案為微細圖案的緣故，要恢復為與 正常圖案相同則顯得相當的困難。為解決該問題，專利文 獻2記載有不是恢復為與正常圖案相同的形狀，而是藉由 形成為可獲得與正常圖案具有相同的灰階效果的修正圖案 以進行灰階部之修正的技術。 (專利文獻1 ) 日本專利特開2 0 0 0 - 1 1 1 9 5 8號公報 (專利文獻2 ) 日本專利特開2 0 0 2 - 1 0 7 9 1 3號公報 (非專利文獻1 ) 月子1J FPD Intelligence， p. 3 1 - 3 5, 1 9 9 9 年 5 月 【發明内容】 (發明所欲解決之問題） 即使使用如上述專利文獻2之修正方法，要以修正圖案 成為與正常圖案相同效果的等級來提升修正精度，則顯得 非常困難，因此有使得灰階罩幕之良率劣化的問題。另一 方面，作為在T F T基板上產生的缺陷之一，如可列舉源極 與汲極的短路。因此，在上述源極與汲極之間為形成介入 之電路部之目的而使用之灰階罩幕中，對應電路部之灰階 部的加工精度成為非常重要的要素。 在此，本發明係為解決上述問題點而完成者，其目的在 於，提供一種灰階罩幕之缺陷檢查方法，可保證為不會使 灰階罩幕製造之良率降低，可防止在TFT基板產生缺陷的 7 312/發明說明(補件)/93-06/93109051 1244671 部之缺陷檢查的缺陷臨限值設為，黑缺陷側為正常之缺陷 臨限值，白缺陷側為較正常之缺陷臨限值降低其缺陷臨限 值者。 (實施例） [實施例1 ]:灰階部之檢查 使用灰階罩幕在光阻膜上進行圖案轉印，藉由模擬求得 顯像後之光阻膜的膜厚（在將對應遮光部的光阻膜設為 1 0 0時的對應灰階部的光阻膜）。對應灰階部的光阻膜，理 想上為4 0〜5 0。在習知之灰階部之缺陷檢查步驟中，將具 有超過指定允許範圍的缺陷等級的黑缺陷及/或白缺陷的 罩幕作為不良予以抽出時之上述指定允許範圍，係將其缺 陷臨限值設為在黑缺陷側為5 0 ’在白缺陷側為4 0 ’以此進 行缺陷檢查。 本次係將其缺陷臨限值設為在黑缺陷側為5 0 ’在白缺陷 側為3 0，來進行缺陷檢查。其結果為可以高良率進行灰階 罩幕之製造，且無TFT基板之缺陷產生。 [實施例2 ]:灰階罩幕之修正 如圖1 ( 1 )所示，在產生有缺失局部圖案的白缺陷的灰階 部，如圖1 ( 2 )所示，使用雷射C V D施以在正常白缺陷側缺 陷臨限值中成為白缺陷圖案的修正圖案（本發明中，稱為白 缺陷圖案側修正圖案）。針對如此般修正後的灰階罩幕的灰 階部，以與上述相同的缺陷臨限值進行相同的缺陷檢查的 結果，其缺陷等級處於允許範圍内。 [比較例1 ] 10 312/發明說明書(補件)/93-06/93 109051 1244671 與實施例2相同，在產生有缺失局部圖案的灰階部，與 實施例2相同使用雷射CVD嘗試正常圖案與相同線寬的修 正圖案的形成。但是，如圖2所示，其線寬變粗。針對如 此般修正後的灰階罩幕的灰階部，以與上述相同的缺陷臨 限值進行相同的缺陷檢查的結果，其缺陷等級未處於允許 範圍内。 又，灰階罩幕之檢查或修正並不侷限於上述方法。 另外，針對灰階部，並不侷限於形成有微細圖案者，也 可使用半透過膜。 又，本發明之灰階罩幕並不侷限於習知技術所示步驟中 所使用者，其也可用於其他的TFT基板製造步驟者。 (發明效果） 根據本發明，可得一種灰階罩幕之缺陷檢查方法，其保 證為不會使灰階罩幕製造之良率降低，可防止在TF T基板 產生缺陷的灰階罩幕。 【圖式簡單說明】 圖1為說明實施例2之灰階罩幕修正用的圖，圖1 ( 1 ) 為說明產生有白缺陷的灰階部用的模型圖，圖1 ( 2 )為說明 在正常白缺陷側缺陷臨限值中形成成為白缺陷圖案的修正 圖案的狀態用的模型圖。 圖2為針對產生有圖1 ( 1 )所示白缺陷的灰階部，說明由 比較例1形成的修正圖案用的模型圖。 圖3 ( 1 )〜（3 )為說明使用灰階罩幕之TF T基板的製造步 驟（前半）的一例用的圖。 11 312/發明說明書(補件)/93-06/93109051 1244671 圖4 ( 1 )〜（3 )為說明使用灰階罩幕之T F T基板的製造步 驟（後半）的一例用的圖。 圖5為說明灰階罩幕用的模型圖。 (元件符號說明） 1 玻璃基板 2 閘極 3 閘極絕緣膜 4 第1半導體膜（a - S i :非晶質矽） 5 第2半導體膜（摻N +非晶質矽） 6 源極汲極用金屬膜 6 a 源極 6 b 及極 7 光 阻 膜 7a 第 1 光 阻 圖 案 7b 第 2 光 阻 圖 案 8 灰 階 罩 幕 11a 遮 光 部 lib 遮 光 部 1 2 透 光 部 13 灰 階 部 13a 遮 光 圖 案 13b 透 過 部 312/發明說明書(補件)/93-06/93109051 121244671 (1) Description of the invention: [Technical field to which the invention belongs] The present invention relates to a defect inspection method for a gray-scale portion of a gray-scale mask for manufacturing a thin film transistor substrate for a liquid crystal display device. [Previous Technology] Compared with thin film transistor liquid crystal display devices (hereinafter referred to as TFT-LCD), because of the advantages of being easy to be thin and having low power consumption, the modernization process is rapidly developing. TFT-LCD has a plate with a structure in which TFTs are arranged on each pixel arranged in a matrix in a liquid crystal interlayer, and a color filter in which red (R), green (G), and blue (B) images are arranged corresponding to each pixel. The general structure of the optical device. In T F T-L C D, only TF T substrates are manufactured using 5 to 6 masks. Under such circumstances, a method for manufacturing a board using a four-light mask (for example, Non-Patent Document 1, Patent Document) has been proposed. This method uses a light-shielding portion, a light-transmitting portion, and a gray-scale portion (hereinafter (Referred to as gray-scale mask) to reduce the number of masks used. An example of the manufacturing process of a TFT substrate using a gray-scale mask is shown. A metal film for the gate is formed on the glass substrate 1 by using photolithography. A gate electrode 2 is formed in the process. Thereafter, a gate insulating film 3, a first body film 4 (a-Si: amorphous silicon), and a second semiconductor film 5 (a metal film for doped N + amorphous source drain 6) are formed. And photoresist film 7 (Fig. 3 (1)). Second, a positive photoresist is exposed and developed with a gray-scale mask 8 to form a TFT and a source-drain formation area, and an area covered with a data line and an area. The first photoresist 312 / Invention Specification (Supplement) / 93-06 / 93109051 plate, which is thinner than the source-drain formation area, and the CRT and its commercial products have more TFT-based element patterns and TFT-based. The photomask 3 of the ° shows a semiconducting silicon of the photomask), and the circuit part circuit part pattern 5 1244671 7 a (Fig. 3 ( 2 )). Next, using the first photoresist pattern 7a as a photomask, the source and drain metal film 6 and the first and second semiconductor films 4, 5 are etched (FIG. 3 (3)). Next, the second photoresist pattern 7 b is formed by removing the thin photoresist film in the area where the circuit portion is formed by ashing with oxygen (FIG. 4 (1)). Then, using the second photoresist pattern 7 b as a photomask, the source / drain metal film 6 is etched to form the source / drain electrodes 6 a and 6 b, and then the second semiconductor film 5 (FIG. 4 (2 )), And finally the remaining second photoresist pattern 7 b is peeled off (FIG. 4 (3)). As the gray-scale mask 8 used here, as shown in FIG. 5, the light-shielding portions 1 1 a and 1 1 b corresponding to the source / drain electrodes; the light-transmitting portion 12 and the gray-scale portion 1 corresponding to the circuit portion. 3. The gray scale portion 13 is a region where a light-shielding pattern 1 3 a below a resolution limit of a large-scale L CD exposure machine using a gray scale mask is formed. The light-shielding portions 1 1 a, 1 1 b, and the light-shielding pattern 1 3 a are usually formed of a film having the same film thickness and composed of the same material such as chromium or a chromium compound. The resolution limit of a large LCD exposure machine using a gray scale mask is about 3 // m in a stepper, and about 4 // m in a specular projection. Therefore, for example, in FIG. 5, the spatial width of the transmission portion 1 3 b of the gray scale portion is set to be less than 3 // m, and the line width of the light-shielding pattern 1 3 a below the resolution limit of the exposure machine is set to be less than 3 // m. However, as in the above-mentioned gray-scale part of the gray-scale mask, the fine and coarse of the light-shielding pattern 1 3 a will occur due to reasons such as the difficulty in fine pattern processing or the large influence of dust generated during the manufacturing process. CD defects such as pattern failures or pattern defects caused by redundant patterns or missing patterns (hereinafter, the pattern is too thick or the excess pattern defects are called black defects, and patterns are too thin or the missing pattern defects are called white defects). 6 312 / Invention Manual (Supplement) / 93-06 / 93109051 1244671 Here, although the above-mentioned defects that exceed the allowable range are corrected by patterns, the pattern of the grayscale part is a fine pattern, so it should be restored to the same as It is quite difficult to have the same normal pattern. In order to solve this problem, Patent Document 2 describes a technique for correcting the grayscale portion by forming a correction pattern that has the same grayscale effect as the normal pattern, instead of returning to the same shape as the normal pattern. (Patent Document 1) Japanese Patent Laid-Open No. 2 0 0-1 1 1 9 5 8 (Patent Document 2) Japanese Patent Laid-Open No. 2 0 0 2-1 0 7 9 1 3 (Non-Patent Document 1) Confinement 1J FPD Intelligence, p. 3 1-3 5, 1 959 [Contents of the Invention] (Problems to be Solved by the Invention) Even if a correction method such as the above-mentioned Patent Document 2 is used, the correction pattern must be used as It is very difficult to improve the accuracy of the correction with the same effect level of the normal pattern, so there is a problem that the yield of the gray scale mask is deteriorated. On the other hand, as one of the defects generated on the TFT substrate, a short circuit between the source and the drain can be cited. Therefore, in the gray-scale mask used between the source and the drain for forming the intervening circuit portion, the processing accuracy of the gray-level portion corresponding to the circuit portion becomes a very important factor. Here, the present invention is made to solve the above problems, and its object is to provide a method for inspecting the defects of a gray scale mask, which can ensure that the yield of the gray scale mask is not reduced, and can prevent The defect threshold of 7 312 / Invention Note (Supplement) / 93-06 / 93109051 1244671 of the substrate defect is set as the defect threshold of the black defect side is normal, and the defect threshold of the white defect side is more normal. Defective threshold lowers its threshold. (Example) [Example 1]: Gray scale inspection was performed on the photoresist film using a gray scale mask, and the thickness of the photoresist film after development was determined by simulation (the corresponding light shielding Part of the photoresist film when set to 100 corresponding to the grayscale part of the photoresist film). Corresponding to the photoresist film in the gray scale part, it is ideally 40 to 50. In the conventional defect inspection step of the gray-scale department, the above-mentioned specified allowable range when the black and / or white defects with a defect level exceeding a specified allowable range is extracted as a defect is the defect threshold. The defect inspection was performed by setting 50 'on the black defect side and 4' on the white defect side. This time, the defect threshold is set to 50 'on the black defect side and 30 on the white defect side for defect inspection. As a result, gray-scale masks can be manufactured with a high yield, and no defects of the TFT substrate are generated. [Embodiment 2]: The correction of the gray scale mask is shown in FIG. 1 (1), and the gray scale portion with white defects with missing partial patterns is shown in FIG. 1 (2). A correction pattern that is a white defect pattern in the normal white defect-side defect threshold (in the present invention, it is referred to as a white defect pattern-side correction pattern). As a result of performing the same defect inspection on the grayscale portion of the grayscale mask after such a correction with the same defect threshold as described above, the defect level is within the allowable range. [Comparative Example 1] 10 312 / Invention Specification (Supplement) / 93-06 / 93 109051 1244671 As in Example 2, a gray scale portion with a missing partial pattern was generated. It was the same as Example 2 and it was normal to use laser CVD. Formation of a pattern and a correction pattern of the same line width. However, as shown in FIG. 2, the line width becomes thick. As a result of performing the same defect inspection on the gray scale portion of the gray scale mask thus corrected with the same defect threshold as described above, the defect level was not within the allowable range. In addition, the inspection or correction of the gray scale mask is not limited to the above method. The gray scale portion is not limited to those having a fine pattern, and a semi-permeable film may be used. In addition, the gray-scale mask of the present invention is not limited to users in the steps shown in the conventional technology, and it can also be used in other TFT substrate manufacturing steps. (Effects of the Invention) According to the present invention, a defect inspection method of a gray scale mask can be obtained, which guarantees that the gray scale mask manufacturing yield will not be reduced, and a gray scale mask can be prevented from generating defects on a TTF substrate. [Brief Description of the Drawings] FIG. 1 is a diagram for explaining the correction of a gray scale mask in Embodiment 2. FIG. 1 (1) is a model diagram for explaining a gray scale portion having white defects, and FIG. 1 (2) is an illustration. A model diagram for a state in which a correction pattern to be a white defect pattern is formed in a normal white defect-side defect threshold. Fig. 2 is a model diagram for explaining a correction pattern formed in Comparative Example 1 for a grayscale portion where the white defect shown in Fig. 1 (1) is generated. 3 (1) to (3) are diagrams for explaining an example of a manufacturing process (first half) of a TF T substrate using a gray scale mask. 11 312 / Invention Specification (Supplement) / 93-06 / 93109051 1244671 Figures 4 (1) to (3) are diagrams illustrating an example of the manufacturing process (second half) of a TFT substrate using a gray scale cover. Fig. 5 is a model diagram for explaining a gray scale mask. (Description of Element Symbols) 1 Glass substrate 2 Gate 3 Gate insulating film 4 First semiconductor film (a-Si: amorphous silicon) 5 Second semiconductor film (doped with N + amorphous silicon) 6 Source drain Metal film 6 a for source 6 b and electrode 7 Photoresist film 7a 1st photoresist pattern 7b 2nd photoresist pattern 8 Gray scale mask 11a Light shielding part lib Light shielding part 1 2 Light transmitting part 13 Gray scale 13a Light shielding Pattern 13b Transmissive section 312 / Invention manual (Supplement) / 93-06 / 93109051 12