互補式金屬氧化半導體影像感測元件製程之高深寬比光阻製作方法

Abstract

本論文主要先探討CMOS影像感測元件及其結構和發展趨勢，並發現在微縮製程以及像素尺寸的同時，訊號與雜訊比趨於嚴重讓大家開始著重於改善串擾效應(cross talk)，在改善串擾效應的方法中，高深寬比的光阻製程成為CMOS影像感測元件中重要製程能力的指標之一。 本文所討論的高深寬比的光阻的製造方法，需先經由二次離子質譜儀 (secondary ion mass spectroscopy；SIMS) 分析確認該離子植入強度所需的光阻厚度，以及在此光阻厚度的微影製程條件下找到足夠的製程容忍度(process window)、微影製程足夠的景深(depth of field, DOF)以及曝光容忍度(exposure latitude, EL)等的製程條件後，還以掃描式電子顯微鏡(scanning electron microscope, SEM)確認光阻的剖面形狀、結構等是否健全來判斷製程能力的好壞。最後再以光罩尺寸差異、曝光光源形狀、曝光焦距深度差異、熱盤溫度差異等實驗討論高深寬比光阻的製程改善。

This thesis investigates photo-resists for CMOS image detecting component and structure. When microelectronic industry tries reduce the pixel size, the noise becomes a serious issue, and makes us start to engage and try to improve cross talk issue. In cross talk improvement method, high aspect ratio in photo-resist becomes the one of the most important manufacturing challenges. In this thesis, high aspect ratio of photo-resist manufacturing process has to be examined through secondary ion mass spectroscopy (SIMS). The optimal thickness of the photo-resist can be determined. We study the process tolerance (process window)、depth of field (DOF) in photo-lithography, and exposure latitude (EL) etc. Scanning electron microscope, (SEM) was used to examine the photo-resist profile. Finally, mask size, lightness, focus, and temperature factors are also discussed to improve the fabrication of high-aspect-ratio photo-resist.