微纳电子技术

采用Bosch技术研究了在Si深槽刻蚀中刻蚀/钝化比、刻蚀阶段钝化气体保护时间、刻蚀和钝化工艺重叠时间等工艺参数对刻蚀结果的影响。通过不同工艺条件的试验,发现刻蚀钝化比是影响侧壁结构的主要因素,其大小直接影响了深槽的垂直度;适当增加刻蚀阶段钝化气体通入时间对减小线宽损失有很大的作用,但增加过多会产生长草效应;合适的刻蚀和钝化工艺重叠时间,不仅可以减小侧壁表面的起伏度,还可以一定程度上减小线宽损失。采用刻蚀/钝化比为7:5、刻蚀阶段钝化气体通入时间为25min、刻蚀、钝化工艺重叠时间分别为0.5、1s的工艺条件,成功地实现了一个垂直度达(90±0.1)°、深40μm、线宽损失小于50nm的Si深槽刻蚀结构。

The large effects of the process parameters such as etch and deposition ratio,time of adding passivation gas in etch phase and overrun time of etch and deposition on etching of deep silicon trenches were studied through Bosch technology.By experiments with various parameters,it is found that the ratio of etch and deposition is the major factor controlling the basic profile of trench,which determines the verticality of the profile directly,prolonging properly the time of adding passivation gas in etch phase can decrease the critical dimension(CD) loss enormously,but overly doing can cause grass effect.With proper etch and deposition overrun time,the roughness of sidewalls could be reduced greatly,and the CD loss was decreased by a certain extent.When the process parameters of the etch and deposition ratio was 7∶5,the time of adding passivation gas in etch phase was 25 min and etch and deposition overrun time was 0.5,1 s respectively,a(90±0.1)° profile with 40 μm deep and less than 50 nm CD loss trench without grass effect was realized successfully.