双重掩蔽层实现石英晶体高深宽比刻蚀

Double Masks Used to Realize High Aspect Ratio Etching of the Quartz Crystal

由于石英晶体的刻蚀速率小,要实现石英晶体的高深宽比刻蚀,常用的光刻胶或金属掩膜不能满足工艺要求。提出使用双重掩蔽层的方法实现石英晶体的高深宽比刻蚀,即石英晶体和单晶硅键合,然后在单晶硅表面生长二氧化硅,二氧化硅作为刻蚀单晶硅的掩蔽层,单晶硅作为刻蚀石英晶体的掩蔽层。ICP刻蚀过程使用SF6作为刻蚀气体、C4H8作为钝化气体、He作为冷却气体。控制好气体的流量和配比,选择合适的射频功率,能刻蚀出深度为30μm,宽度为50μm的深槽。该工艺对开发新型石英晶体器件有积极的意义。

Due to the low etching rate, common photoresists and metal masks cannot meet the technological requirements of the high aspect ratio etching of the quartz crystal. Double masks were used to realize high aspect ratio etching of quartz crystal, i. e. the bonding of quartz crystal and monocrystal silicon. Silicon dioxide was created on the surface of monocrystal silicon and was used as a mask to etch silicon. Meanwhile, silicon was used as a mask to etch quartz crystal. In the process of ICP etching, SF6 was used as etching gas, C4Hs as passivation gas and He as cooling gas. With a good control of gas volume and ratio and an appropriate selection of RF power, a groove of 30 um deep and 50 um wide can be etched. This new technology is significant for developing new quartz devices.