单晶硅各向异性湿法刻蚀的研究进展

单晶硅各向异性湿法刻蚀是制作硅基微电子机械系统(MEMS)器件的重要步骤之一,由于具有刻蚀均匀性好、批量大、成本低的优点而深受关注。首先回顾了单晶硅各向异性湿法刻蚀的刻蚀机理,比较了三种常用各向异性刻蚀液的刻蚀性质,讨论了刻蚀形状的控制技术。然后着重介绍了表面活性剂修饰的单晶硅各向异性湿法刻蚀速率和刻蚀表面光滑度等特性,以及面向MEMS应用的基于该刻蚀技术的各种微纳新结构;分析了表面活性剂分子在刻蚀过程中的作用,强调了表面活性剂分子在单晶硅表面的吸附性对改变刻蚀表面的物理性质的重要性。最后在此基础上,归纳了单晶硅各向异性湿法刻蚀的发展情况,探讨了其未来的发展方向。

Development of the Anisotropic Wet Etching on the Single-Crystalline Silicon

The anisotropic wet etching on the single-crystalline silicon is one of the most important processes in the fabrication of silicon-based micro-electromechanical systems(MEMS).It has attracted much attention because of the etching uniformity,batch fabrication and low cost.The etching mechanism of the anisotropic wet etching on the single-crystalline silicon is reviewed.The etching characteristics of three common anisotropic etchants are compared.The technologies for controlling etched profiles are discussed.Then,the etching characteristics(e.g.etching rate and etched surface smoothness) and a variety of novel micro/nano structures for MEMS applications based on the surfactant-modified anisotropic wet etching are significantly introduced.The effect of surfactant molecules in etching process is analyzed,and the importance of the surfactant molecule adsorption on the single-crystalline silicon to change the physical property of the surface is emphasized.At last,on the basis of the above,the development of the anisotropic wet etching on single-crystalline silicon is concluded,and its direction in future is discussed.