Study on Fabrication of High Power Electrostatic Microactuators Using High Aspect Ratio X-ray Lithography

1.研究了利用紧凑型同步辐射光源进行高深宽比X射线光刻（LIGA）的工艺条件优化。在1996年春季安装的最小的超导SR光源“AURORA”上建立了LIGA工艺专用的光束线。在立命馆大学，并进行了操作。确定了PMMA的曝光和显影工艺条件，并在3 A min和32 A min的曝光剂量下分别制作了200 μ m和100 μ m深的PMMA微结构。使用CAD系统设计掩模图案。X射线掩模由2 μ m厚的SiC膜和5 μ m厚的Au吸收体组成，以优化X射线曝光的对比度。使用的X射线掩模，PMMA抗蚀剂结构与2微米宽，200微米高，纵横比为100的曝光和开发，和镍微结构的生产使用镍电铸。3.3-D高功率微致动器的设计，制造和评价。微致动器的基本结构由作为固定电极和可动电极的Ni微结构、Ni种子层、作为隔离层和牺牲层的SiO_2以及Si衬底组成。Ni微结构的尺寸为100 μ m的高度，2 μ m的最小线宽，2 μ m的最小间隙和50的最大纵横比。采用LIGA工艺结合SR光源的高深宽比X射线光刻和电铸技术，制作了梳状驱动静电微驱动器和静电微摆动电机。在65 V脉冲电压和125 V-12相脉冲电压作用下，梳齿驱动静电微驱动器和静电微摆动电机实现了运动。

1.Optimization of process conditions for high aspect ratio X-ray lithography (LIGA) using the compact synchrotron radiation (SR) light source has been investigated. An exclusive beam-line for LIGA process has been set-up on the smallest super conductive SR light source "AURORA", installed in 1996, spring. in Ritsumeikan Univ., and operated. Process conditions for exposure and development of PMMA, were founded, and PMMA microstructures of 200 mum-deep and 100 mum-deep were fabricated under exposing dosage of 3 A min and 32 A min.2.An X-ray mask for LIGA has been fabricated. Mask patterns were designed using a CAD system. The X-ray mask is consisted of 2 mum-thick SiC membrane and 5 mum-thick Au absorber in order to optimize contrast for X-ray exposure. Using the X-ray mask, PMMA resist structures with 2 mum-wide, 200 mum-high and aspect ratio of 100 were exposed and developed, and Ni microstructures were produced using Ni electroforming.3.3-D high power microactuators have been designed, fabricated and evaluated. The basic structure of microactuators is consisted of Ni microstructures as fixed electrodes and movable electrodes, a Ni seed layer, SiO_2 as an isolation layer arid a sacrificial layer, and Si substrate. Dimensions of Ni microstructures were height of 100 mum, minimum line width of 2 mum, minimum gap of 2 mum and maximum aspect ratio of 50. A comb-drive electrostatic microactuator and an electrostatic micro wabble motor were fabricated by LIGA process combined high aspect ratio X-ray lithography using SR light source and electroforming. The comb-drive electrostatic microactuator and electrostatic micro wabble motor were confirmed to move by applying 65V pulse voltage and 125V-12 phases pulse voltage, respectively.