高密度RF等离子体刻蚀工艺直流自我偏压的研究

直流自我偏压作为高密度射频(RF)等离子体刻蚀工艺中的重要电学参数,反映出具有高能量的离子对待刻蚀晶片的轰击效果,后者决定了刻蚀工艺的各向异性、刻蚀速率、选择比及形貌特征等工艺结果。该文以HBr作为刻蚀气体,采用电感耦合等离子体(ICP)金属刻蚀系统针对刻蚀工艺中的直流自我偏压进行研究。研究中分别改变离子源功率、衬底偏压功率、刻蚀压力及HBr气体流量,观察直流自我偏压及其峰值的相应变化规律。实验结果表明,随着离子源功率的升高,直流自我偏压将会轻度降低;升高偏压功率则会显著提升直流自我偏压。刻蚀压力与直流自我偏压呈正比例关系,HBr气体流量的变化及待刻蚀晶片的材质对直流自我偏压无显著影响。

Study on DC Self-Bias of High Density RF Plasma Source Etching Process

DC self bias is the important process reading of high density RF plasma source etching process, by which ion energy and wafer bombardment are decided. In this research, ICP etcher is used and the effects of plasma power,platen power,etcher chamber pressure and HBr gas flow on the DC self bias are studied by using HBr as the etching gas. The result shows that the higher DC self bias is achieved when elevating either platen power or reactor pressure and the lower DC self bias is gotten while plasma power is increased. The effect of HBr gas flow and etched wafer materials on the DC self bias are not seen obviously in this process regime.