微F-P腔可调谐滤波器关键工艺研究

Study on key fabrication process of micro F-P cavity tunable filter

采用表面加工工艺,AZ5214E光刻胶进行光刻并反转,磁控溅射Ni Cr合金,剥离出高度为2.3μm的金属桥墩,填充聚酰亚胺作为牺牲层,再在牺牲层上光刻、沉积金属形成金属桥面,在金属桥面的中心嵌入第二布拉格反射镜。采用O2等离子体刻蚀去除聚酰亚胺膜,制作成微法布里—珀罗(F-P)腔,不需要硅片键合,克服了传统F-P腔高度不够高、调谐范围有限、腔平整度不好以及对设备要求高的缺点,并且可以做出大阵列结构,易于探测器集成。着重对腔体关键工艺,即金属桥墩的Ni Cr剥离工艺进行研究,针对现有技术缺陷,提出解决办法。

Using surface processing technology,AZ5214 E photoresist lithography and inverted,magnetron sputtering Ni Cr alloy,stripping out metal pier with height of 2. 3 μm,fill polyimide as sacrificial layer,and then on sacrificial layer photolithography,depositing metal to form metal bridge,in the center of metal bridge surface,embed the second Bragg reflector. Using O2 plasma etch and remove polyimide film,form cavity structure,without silicon bonding,overcome shortcoming that height is not high enough and the limited tuning range of traditional FP cavity,bad flatness of cavity and low demand of equipment,and it can make a large array structure,easy to integrate with the detector. Focus on key fabrication process that is Ni Cr metal stripping process,propose solutions based on existing technical defects.