红外微腔探测器中金属支撑柱的制备工艺研究

Fabrication of Fine-line Ti Interlinked Micro Pillar Used in Infrared Detector

基于一般正胶光刻工艺的剥离工艺，所需胶膜的厚度要大大超过剥离薄膜的厚度.这样在剥离线宽小、厚度大的微腔结构探测器的金属互连柱图形时就会存在光刻分辨率低、剥离难的问题.本文重点研究了基于AZ5214E光刻胶图像反转性能的剥离工艺，对图像反转光刻所特有的反转烘、掩模曝光、泛曝光工艺条件进行了详细的对比实验.结果表明：当反转烘温度为96-98℃，第一次掩模曝光时间和泛曝光时间分别为8.1 s、8.4 s时，可以得到较好的光刻图形.通过电子束蒸发Ti，成功剥离出高2.40μm、面积3.0μm×3.0μm的Ti微互连柱.此工艺的优点在于分辨率高，胶膜与剥离薄膜的厚度比接近1时，也能剥离出所要图形，可以用于制备MEMS微腔器件中的微互连柱.

The lift-off technic based on traditional photolithography using positive photoresist, which requests the thickness of photoresist must be more than that of thin film. Therefore,it is hard to lift-off fine line metal micro pillar with high thickness used in micro electrical mechanics system（MEMS） detector with micro cavity. The image-reversal technology using AZ5214E photoresist was studied in detail. The influence of reversal bake,exposure time,as well as flood exposure time were analyzed,and the good pattern of photoresist was obtained when the temperature reversal bake was varied from 96℃ to 98℃ ,and the exposure time and flood exposure time were 8.1 s and 8.4 s respectively. Ti thin film was grown on the pattern by e_beam evaporation. Finally,Ti Micro Interlinked Pillar was fabricated using lift-off technology. The dimension of Ti pillar was 2.40 μm ×3.0 μm × 3.0 μm. We can lift off the thin film successfully even when its thickness was close to that of the photoresist. This technic can be used in fabrication of Interlinked micro pillar in MEMS device.