研究了一种准LIGA加工工艺。该工艺利用无氰电铸制作金结构层,采用PECVD制作的无定形硅作为牺牲层,利用二氟化氙(XeF2)干法腐蚀对材料选择性好的特点,采用先部分封装然后腐蚀牺牲层释放结构的工艺流程,避免了封装工艺对可动敏感结构造成的破坏。研究了无氰电铸结构中的应力梯度,发现应力梯度存在随时间缓慢释放的现象,利用热退火消除了结构中的应力梯度。同时还对厚胶光刻、类特氟隆防粘附层制备等关键工艺作了探讨。
A UV-LIGA process was studied. Gold was used as structural material fabricated with non-cyanide electroplating. PECVD α-Si was used as sacrificial material. Thanks to the good etch selectivity of XeF2, the structure was released after packaging to avoid the structure being destroyed by package processes. The stress gradient in the electroplated structure was studied. The result shows that the stress gradient decreases continuously in the room temperature and can be relaxed with thermal annealing. Realization of thick moulds and Teflon-like anti-stiction film was also discussed.