負型化學放大阻劑之鹼污染作用研究

Abstract

配合半導體工業進入次微米時代，阻劑設計理念朝高靈敏度、高對比度及高圖案解像度的方向進行，因此開發出含光酸產生物化學放大型阻劑（簡稱化學放大型阻劑），且成為目前阻劑之主流。化學放大型阻劑於製程上所面臨的問題大致可分酸損失和酸擴散兩方面，其中以鹼性污染造成的酸損失影響最大，因其可使正型化學放大型阻劑產生T型頂或底腳之阻劑輪廓；使負型化學放大型阻劑產生相反之輪廓。文獻對污染問題的報導，著重於利用電子顯微鏡進行阻劑輪廓量測或提出降低污染之方法。至於污染對顯影速率的影響，有系統的報導不多。 本論文之研究內容乃藉由雷射干涉儀觀測負型化學放大型阻劑SAL601之顯影速率，並探討污染歷程對顯影速率之影響。研究發現： 1.利用Fukuda顯影模型，配合阻劑Dill參數，可求得負型化學放大型阻劑SAL601中光酸於NH3污染環境下消耗分佈之資訊 2.負型化學放大型阻劑SAL601經曝光NH3污染製程處理後，NH3中和質子酸，減少交連反應，使顯影速率增加。 3.負型化學放大型阻劑SAL601經NH3污染╱曝光製程處理後，呈現顯影抑制現象，顯影速率降低，非因交連引起，而可能因其他難溶物生成所致。 4.負型化學放大型阻劑SAL601經NH3污染╱曝光╱NH3污染製程處理後，原先污染╱曝光製程所造成之顯影抑制現象獲得改善。 5.曝光前與曝光後之NH3污染對負型化學放大型阻劑SAL601之影響與作用機制不同。 本論文根據實驗結果歸納，提出鹼性污染物對光酸阻劑之污染行為，有可能因污染歷程不同，產生顯影行為差異之概念。與此相關問題值得進一步深入研究。

As semiconductor industries get into submicron age, the design concept for resists is directed to high sensitivity, high contrast and high resolution, hence, chemically amplified resists with photoacid generators have been developed and become the main stream of resists at present. Problems for the process of chemically amplified resists can be generally divided into acid loss and acid diffusion. The most serious problem for acid loss comes from basic pollution. Basic pollution can cause positive-tone resists to have profiles with T-top and foot and the negative-tone resists a reverse profile. In recent literature review, we found that most studies in the field of basic pollution were related to the measurement of resist profile or to methods of lowering pollution. Few were found about the relationship between pollution and development rate of the resist. In this thesis, using laser interferometry, we observed the development rate of the negative-tone resist SAL601 under the influence of different processes of NH3 pollution. Results are summarized as follows: 1.We can get the range of acid loss in the resist under the pollution of ammonia by using Fukuda's model and Dill's parameters. 2.After chemically amplified negative-tone resist SAL601 underwent the process of exposure/NH3 pollution, NH3 neutralized proton acid and caused the development rate to become faster by lowering the degree of polymer cross-link. 3.After chemically amplified negative-tone resist SAL601 underwent the process of NH3 pollution/exposure, it exhibited development inhibition and made the development rate slowing down. This was not caused by polymer cross-link, but, may be, caused by the generation of development inhibitors. 4.When chemically amplified negative-tone resist SAL601 underwent the process of NH3 pollution/exposure/NH3 pollution, it could reduce the effect of development inhibition resulted from the process of NH3 pollution/exposure before. 5.The effects of NH3 pollution on chemically amplified negative-tone resist SAL601 between processes exposure/NH3 pollution and NH3 pollution/exposure are different. The mechanism for this difference in effect is still unclear. We summarized our studies and proposed the concept that development rate would be changed dramatically by different processes of pollution. The related study is worthy to go on further.