UV-LIGA技术制作微型螺旋形加速度开关

微型加速度开关是用于空间飞行体中感受加速度并完成致动的重要惯性器件。本文采用UV-LIGA技术,结合SU-8厚胶工艺、微电铸工艺以及牺牲层技术,制作了微型螺旋形加速度开关。研究了牺牲层工艺、SU-8光刻技术以及螺旋形弹簧形变控制等微细加工的工艺细节;分析了多种牺牲层材料的特性,优选了与工艺相适应的Zn牺牲层体系,解决了微结构易脱落的工艺问题。通过优化微电铸工艺来减小金属膜层的内应力,优化牺牲层释放工艺来避免腐蚀过程对弹簧膜结构的冲击。实验结果表明,通过工艺优化可得到平整的微型螺旋形弹簧—质量块结构,螺旋弹簧厚度为20μm,质量块厚度达200μm,本文的工作可为大批量、低成本地研制微型加速度开关提供工艺基础。

Fabrication of micro spiral acceleration switch using UV-LIGA technology

The micro acceleration switch is an important inertial device for measuring itself acceleration and triggering switch in a flight control system. A micro spiral acceleration switch was fabricated in this paper by using UV-LIGA technology combining with SU-8 thick resist process, micro electroforming and sacrificial layer technology. The fabrication processes of the microstructures, such as sacrificial layer technology, SU-8 lithography and the distortion control of spiral spring structures, were studied in detail. The properties of various sacrificial layer materials were analyzed and the Zn film was chosen as a sacrificial layer to avoid the desquamation of microstructures. The flat spiral spring and mass block structures were obtained by optimizing the electroforming parameters to minimize the inner stress of Ni microstructures and controlling the releasing process of sacrificial layer to avoid the impact of chemical reaction on the Ni spiral films. The obtained spiral spring and the mass block show their thicknesses to be 20 μm and 200 μm, respectively. The result indicates that it is reliable to produce micro spiral acceleration switches in batches by using this fabrication process.