微影製程中多層光阻的模擬與研究

Abstract

為了能得到更好的解析度，在深次微米中的微影製程中，多層光阻的使用乃是不可或缺的。由於薄膜中光學干涉的效應，光阻的曝光後的輪廓會有震盪(swing) 的情形，通常使用曝後烤（Post Exposure Bake）加以避免；然而曝後烤往往會增加臨界寬度(Critical Dimension)，因而減少解析度。多層光阻的使用可以有效改進上述缺點。 多層光阻的使用需要精巧地控制許多變數，為了達到最佳化的效果，必須使用電腦模擬以減少時間與金錢的消耗，因此模擬軟體佔了相當重要的地位。我們發展了一套微影製程的模擬程式，可以精確計算光在薄膜中干涉的行為。利用這套軟體，可以最佳化使用多層光阻所需的眾多參數。在此篇論文中，我們討論了光學干涉行為以及利用不同的晶原結構，示範計算的結果。

To get better resolution, in deep sub-micron lithography process, the use of multi-layer photo-resist is necessary. Because of optical interference in thin film, the shape of exposed resist has so-called swing effect. Usually, PEB (Post Exposure Bake) used to be applied to avoid this effect. However, PEB may increase CD (Critical Dimension control) and degrade the resolution. Multi-layer resist can be prevailing over this effect. In using of this process, there are lots of parameters should be elaborately controlled. To optimize these factors, simulation in computer plays a very important role to decrease the cost of time and money. We build a model to precisely calculate the optical behavior in resists to optimize many parameters which is needed in applying multi-layer resists method. In this paper, we discuss optical interference in thin film and some results from different structure are given for examples.