有機薄膜電晶體主要之兩種結構：上接觸式(TC)結構以及下接觸式(BC)結構，其中前者雖然因接觸電阻較小而有較好的元件特性，但是目前其以金屬遮罩製程為主流而在元件尺寸微縮以及大面積顯示器面板應用上不利。上接觸式結構乃先沉積主動層再沉積源極/汲極，且有機主動層易受化學酸鹼溶液影響，故無法直接以黃光微影方式直接在其上定義源極/汲極圖案，我們希望發展出能以黃光製程來製作上接觸式的有機薄膜電晶體，讓上接觸式(TC)結構亦能應用於元件尺寸微縮，以保持較好的元件特性同時仍有較高積體化密度、較大的平面顯示器之畫素開口率。
為了使有機薄膜電晶體在閘極關閉下有更好的off current，主動層的圖案化是不可避免的。然而主動層的圖案化現階段以金屬遮罩(metal shadow mask)製程方式為主，若要使單位面積下可放入更多電晶體以提高積體化密度，以黃光微影製程進行圖案化是必需要考慮的方法。
我們提出了一種新式的黃光微影製程製作主動層圖案化的方法。並且使用黃光微影製作出TC式有機薄膜電晶體，對其製作方式進行比較與分析，讓小尺寸的應用不再只是BC式結構的優勢，本研究從元件結構著手而改善元件特性，希望能夠作為有機薄膜電晶體領域發展的一個參考。

For organic thin-film transistor (OTFT), there are two common structures: Top-contact (TC) structure and Bottom-contact (BC) structure. The former has better electrical performance than that of the latter because of lower contact resistance. However, TC structure is usually fabricated by metal shadow mask process, and it has some issues for device scaling down and flat panel display (FPD) applications with large area. The TC structure is depositing the active layer before the deposition of source/drain (S/D) electrodes; the organic active layer is vulnerable to chemical solvents, so S/D electrodes cannot be directly patterned upon the organic active layer by using traditional photolithography. We hope to develop a novel S/D pattering scheme with compatibility of traditional photolithography, and fabricate OTFTs with TC structure and scaling down at the same time. Hence, it could obtain higher integration and higher aperture ratio of pixels for FPD without deteriorating the electrical performance of OTFT device.
To reduce the off current of OTFT when the gate is applied as off-state, patterning the organic active layer is inevitable. In addition, the organic active layer is also usually patterned by metal shadow mask process. If more OTFTs can be contained in same area to achieve the higher integration or higher aperture ratio of pixels for FPD, using photolithography process to pattern organic active layer is essential.
We propose a novel lithography process that can pattern the organic active layer and the S/D electrodes without deteriorating the electrical performance of OTFT. Its fabrication process is systematic analyzed. We hope the proposed scheme can be a candidate to fabricate OTFTs with high performance and high integration at the same time.

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