干涉型光罩造成局部光阻厚度不一的研究及其應用

The Study and Application of Gray Tone Mask on the Partial Different Photoresist Layer

葉錦龍(Chin-Lung Yeh)

指導教授 ： 蔡宗燕

中原大學/理學院/化學研究所/碩士(2006年)

https://doi.org/10.6840/cycu200600675

摘要

本論文主要討論應用干涉型光罩(Gray Tone Mask)，因為光學的干涉與繞射效應，會造成曝光能量的不均勻，使得光阻(Photoresist, PR)表面受到不同的曝光能量，在經過顯影(Develop)後，會產生光阻高度不一的殘留光阻(Photoresist Remain, PR remain) 。將此特性應用在薄膜電晶體液晶顯示器 (Thin Film Transistor–Liquid Crystal Display, TFT-LCD)的TFT元件的半導體層(Semiconductor Electrode, SE)和源極、汲極的電極層(Source Drain Electrode,SD)的曝光製程，曝光後經過蝕刻製程做出SE的圖案(Pattern)，再將較低的光阻殘留灰化(Ashing)後，類似曝光出SD的圖案，於是將兩道的曝光製程合成一道。在論文中將探討一條光柵的寬度(Line)搭配兩條狹縫寬度(Space)的光罩，在顯影後會造成不同高度的光阻殘餘。結果發現當光柵寬度愈寬時光阻殘留愈高；當狹縫寬度愈寬時光阻殘餘愈低；當曝光能量愈高時光阻殘餘愈低。最初始披覆(Coating)的光阻膜厚實驗有2.0 um、1.75 um、1.5 um三種厚度，在實驗數據中可以發現，2.0 um的光阻會有最大的製程餘裕度，當然較厚的光阻，就會消耗較多的光阻耗材，同時也會增加光阻去除的時間，所以條件的選擇沒有絕對，只有適合與不適合的問題。

關鍵字

光阻殘留 ； 薄膜電晶體 ； 干涉型光罩

並列摘要

The applications of the Gray Tone Masks have been studied in this thesis. Their optical interference and diffraction effects show different characteristics in terms of photo exposure energy and critical dimension control. As the exposure energy varies, it is found different photoresist (PR) remained thickness andprofile after PR development. This technique has been applied to the device fabrication of TFT-LCD for semiconductor electrode (SE) layer, Source Drain (SD) Electrode photo process. The SE layer was first patterned and etched. An plasma ashing is then used to remove the thinner portion of remained PR, the SD pattern can be successfully formed. Thus, the two processes, i.e. SE and SD photomasks, can be combined into one single mask. In the following study, we have discussed this new mask technology having one line of optical grating with two seam space. Different PR remained thickness after photo processing is found in various mask design features. The wider of the line of optical grating is used, the thicker of the developed PR thickness remains. And the wider of seam space is used, the thinner of the developed PR remains. Furthermore, the high exposure energy also decreases the PR remained thickness. There are three conditions in thicknesses for coating PR film thickness, i.e. 2.0, 1.75 and 1.5 um respectively. The processing result shows that the 2.0 um PR is best among three processes. However, the thick PR needs large consumption in PR and long PR ashing time. Thus, there is always a trade-off for optimizing the PR thickness and designing Grey Tone masks.

並列關鍵字

Gray Tone Mask ； TFT-LCD

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