跨尺度、高深宽比惯性微开关制作工艺研究

Study on Fabrication Process of Cross-scale Micro Inertial Switch with High Aspect Ratio

采用基于光刻和微电铸的多层UV-LIGA工艺在金属基底上制作了惯性微开关。研究了电铸面积对胶层内应力的影响,解决了胶层从基底脱落的问题。通过实验分析了电流密度对铸层层间结合力的影响,解决了铸层分层问题。通过煮沸无机酸的方式去除高深宽比金属微结构内的光刻胶,解决了SU-8胶去胶难的问题。最终,成功制作出外形尺寸为14 mm×11 mm×0.6 mm的跨尺度、高深宽比惯性微开关,其最小线宽为29.8μm,最大深宽比为17∶1,从而克服了目前制作惯性微开关时基底易碎、需溅射导电种子层、整体尺寸小、深宽比低的局限性。

The micro inertial switch was fabricated on metal substrate by using muhi-layer UV- LIGA process based on photolithography and micro electroforming. The effect of electroforming area on internal stress of photoresist layers was studied,and the detachment problem of photoresist layers caused by high internal stress was solved. The influence of current density on adhesive force between different electroforming layers was analyzed based on experiments,and the detachment problem of electroforming layers was solved. The photoresist in metal microsturcture with high aspect ratio was removed by boiling inorganic acid,and the problem of SU-8 removal was solved. Eventually,a cross- scale micro inertial switch with high aspect ratio was fabricated successfully. The overall size of the inertial switch is 14 mm×11 mm×0.6 mm,the smallest line width is 29.8 μm and the highest aspect ratio is 17：1. The method proposed does not need to sputter conductive seed layer and breaks the limitation of substrate fragmentation, small size and low aspect ratio of the existing methods.