摘要
针对摆式微加速度计的制作,对利用两种添加剂共同修饰的TMAH刻蚀液的单晶硅湿法刻蚀技术及其相关刻蚀特性进行了研究。分析了两种添加剂之间的作用机理及对单晶硅湿法刻蚀的影响,选择合适的添加剂刻蚀液配比,实现了稳定的刻蚀形貌控制。通过两种添加剂的共同作用,获得了具有光滑刻蚀表面(粗糙度约为1nm)和良好凸角保护(凸角侧蚀比率小于0.8)的刻蚀形貌。实验结果表明,在三重溶液(TMAH+Triton-X-100+IPA)下的刻蚀形貌具有明显优势。最后,基于添加剂对疏水性单晶硅材料的作用机理及表面张力调节,表面活性剂和酒精类添加剂之间的相互作用分析了刻蚀形貌发生变化的原因。以典型悬臂梁-质量块的制作为例,验证了采用该单晶硅刻蚀形貌控制方法可以获得微加速度计光滑的悬臂梁表面和无需凸角补偿的完整质量块。相比于其它制作工艺,该方法简单、易操作,有利于提高微机电器件的性能。
For fabrication of microaccelerometers with beam-mass structures, an anisotropic wet silicon etching technology based on ternary TMAH （tetramethyl ammonium hydroxide） solutions containing Triton and IPA was proposed and corresponding etching characteristics was investigated. The underlying mechanism between two kinds of additives （the Triton and IPA） and its effect on the wet silicon etching were analyzed. The appropriate ratio of additives was chosen to control the etching morphology. By a combined action of two kinds of additives, a mirror-like finish surface （Ra≈1 nm） and high reduction of undercutting （the ratio of undercut at the convex corner less than 0.8） were achieved synchronously. The experimental results show that the etched morphology has been dramatically improved by the ternary solutions. Furthermore, the reasons affecting the etched morphology were discussed, and the underlying mechanism on hydrophobic silicon surface, surface tension adjustion and the reciprocity between surfactant and alcohol were used to explain the new etched characteristics. Finally, by taking fabrication of a spring-mass structure for an example, the proposed method is verified by obtaining a very smooth cantilever and a complete mass structure without convex corner compensation. As compared to some other fabrication techniques, this method is very simple, easy to operate and useful in improving the quality of devices.
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2016年第2期350-357,共8页
Optics and Precision Engineering
基金
国家自然科学基金资助项目(No.51305412)
中国工程物理研究院超精密加工技术重点实验室研究基金资助项目(No.2012CJMZZ00003)
关键词
单晶硅
湿法刻蚀
形貌控制
三重溶液
表面粗糙度
凸角
silicon
wet etching
morphological control
ternary solution
surface roughness
convexcorner
