ICP刻蚀对光刻胶掩模及刻蚀图形侧壁的影响

采用AZ1500光刻胶作为掩模对GaAs和InP进行ICP刻蚀,研究了刻蚀参数对光刻胶掩模及刻蚀图形侧壁的影响。结果表明,光刻胶的碳化变性与等离子体的轰击相关,压强、ICP功率和RF功率的增加以及Cl2比例的减小都会加速光刻胶的碳化变性,Cl2/Ar比Cl2/BCl3更易使光刻胶发生变性。对于GaAs样品刻蚀,刻蚀气体中Cl2含量越高,刻蚀图形侧壁的横向刻蚀越严重。Cl2/BCl3对GaAs的刻蚀速率比Cl2/Ar慢,但刻蚀后样品的表面粗糙度比Cl2/Ar小。刻蚀InP时的刻蚀速率比GaAs样品慢,且存在图形侧壁倾斜现象。该工作有助于推动在器件制备工艺中以光刻胶作为掩模进行ICP刻蚀,从而提高器件制备效率。

Effect of ICP Etching on the Photoresist Mask and the Sidewall of the Etching Figure

GaAs and InP were etched with photoresist AZ1500 as a mask,and the effects of ICP etching parameters on photoresist mask and sidewall of etching picture were explored.Results show that the increase of pressure,ICP power and RF power and the decrease of Cl2 ratio will accelerate the carbonized denaturation of the photoresist.Cl2/Ar is easier to introduce the denaturation of the photoresist than Cl2/BCl3.The higher Cl2 ratio in the gas causes the severer lateral etching of GaAs.The etching rate of GaAs by using Cl2/BCl3 is slower than that using Cl2/Ar,but the RMS of GaAs is smaller than that using Cl2/Ar.The etching rate of InP is slower than that of GaAs and the tilted sidewall is observed after removing the photoresist.This work promotes the application of ICP etching using photoresist as a mask,and thus improves the efficiency of device processing.