Study of Polyimide as Sacrificial Layer with O2 Plasma Releasing for Its Application in MEMS Capacitive FPA Fabrication
Polyimide (PI) was a good candidate as the sacrificial layer for its compatibility with CMOS technology. This paper first presented a new patterning method of PI film and then investigated the relationships among undercut rate, the undercut limit length and the releasing hole size in the releasing step, which was helpful and important for its popularity and its application in MEMS capacitive FPA (Focal plane array) fabrication. A new patterning approach of PI film was successfully developed in ICP chamber. The patterning approach selected a PECVD SiO2 layer as patterning mask. The optimized ICP PI recipe was composed of an O2 flow of 180sccm, an electrode power of 400W and bias plate power 200W. With the optimized ICP PI recipe, a vertical etching rate about 0.5-0.6μm/min with a lateral etching rate 0.13μm/min was realized. With 1μm PI sacrificial layer, a 0.22μm/min undercut rate was achieved in a normal barrel etcher. Based on our experimental facts, the optimized releasing hole size was 5μm×5μm and the distance between lateral releasing holes should be fewer than 17 μm for effectively and completely releasing.
Shenglin Ma Ying Li Xin Sun Xiaomei Yu Yufeng Jin
National Key Laboratory on Micro/Nano Fabrication technology, Peking University, Beijing 100871, P. National Key Laboratory on Micro/Nano Fabrication technology, Peking University, Beijing 100871, P.
国际会议
北京
英文
526-529
2009-08-10（万方平台首次上网日期，不代表论文的发表时间）