影响牺牲层腐蚀速率的因素研究

Study of the Factors Affecting the Sacrificial Layer’s Etching Rate

精确预测腐蚀速率对于避免过腐蚀和节省时间,从而提高MEMS器件加工的效率具重大意义。通过改变牺牲层材料、腐蚀液浓度、温度和牺牲层结构来改变腐蚀速率是常用的方法。在前人腐蚀模型基础上考虑扩散系数是浓度和温度的函数,腐蚀速率常数是温度的函数,得到了修正模型。从修正模型中找出影响腐蚀速率的各种因素的对应参数,并对其影响腐蚀速率的机理进行详细地研究,这样就为通过修改某些因素来改变腐蚀速率提供了依据。

To predict the etching rate accurately can not only protect the structure layer from over etching, but also save the etching time. Thus it can enhance the efficiency of MEMS apparatus machining. It is a common way to alter the etching rate by changing the material of sacrificial layer, concentration of etehant, temperature or structure of sacrificial layer. A modified etching model is proposed, in which the diffusion coefficient is a function of the temperature and concentration and the etching rate constant is a function of temperature. The corresponding parameters, which affect the etching rate, are found and the mechanism is analyzed. It will provide evidence to change the etching rote.