CCD多晶硅刻蚀技术研究

Study on Technology of Poly Etch in CCD

CCD晶硅刻蚀相比于传统CMOS工艺的多晶硅刻蚀需要多晶硅对氮化硅更高的刻蚀选择比,更长的过刻蚀时间。采用Cl2+He,Cl2+He+O2,Cl2+He+O2+HBr三种工艺气体组分在Lam4420机台进行了多晶硅刻蚀实验,研究了不同气体配比、不同射频功率对刻蚀速率、选择比、条宽、侧壁形貌等参数的影响。通过优化工艺参数,比较刻蚀结果,最终获得了适合于CCD多层多晶硅刻蚀的工艺条件。

Relative to normal CMOS poly etch process,the technology of poly etch in CCD need higher selectivity between poly and SiN,and more over etch time.Poly etch on Lam4420 machine was performed with Cl2＋He,Cl2＋He＋O2 and Cl2＋He＋O2＋HBr as etching gases.The relationship between different etching gases,RF power and the four parameters of etch rate,selectivity,profile and CD bias was researched.By optimizing the ratio of different gases and comparing the different etching results,the optimized etching process for CCD was obtained.