IGZO-TFT钝化层设计三元复合过孔结构, 出现了20%过孔相关不良。本文以CF4/O2为反应气体, 采用控制变量法, 从功率、气体成分和比例、压力等方面对氧化物TFT钝化层的电感耦合等离子体刻蚀机理进行研究。当钝化层为SiO2或SiNx单组分时, 氧气可以促进刻蚀反应; 随着CF4/O2比例增加, 刻蚀速率先增大后趋于稳定, 并且当CF4/O2=15/8时, 刻蚀速率和均一性达到最优; 与源功率相比, 提高偏压功率在提升刻蚀速率中起主导作用, 同时均一性控制在15%以内; 当压力在4 Pa以内时, 刻蚀速率随着压力的降低而增加。据此分析, 对复合结构SiNx/SiO2、SiO2/SiNx、SiNx/SiO2 /SiNx的刻蚀过程进行优化, 得到了形貌规整、无残留物的过孔, 过孔相关不良得到100%改善。

For ternary composite via-hole in passivation layer, 20% relevant defection happened in IGZO TFT manufaction. In this paper, the inductively coupled plasma etching mechanism of the oxide TFT passivation was investigated. Combined the reaction gas CF4/O2 with the control variable method, the impact of power, gas composition, gas ratio and pressure on the project was studied. When the passivation is a single component of SiO2 or SiNx, adding oxygen to the reaction gas can promote the etching process. The etching rate and uniformity increase with the ratio of CF4/O2. Further, the optimum indexs achieve at CF4/O2=15/8. Compared with the source power, the bias power plays a leading role in increasing the etch rate, while the uniformity is controlled within 15%. The etching rate improves with the decrease of the pressure, within the limit of 4 Pa. Based on this, the etching processes of the composite structure SiNx/SiO2, SiO2/SiNx, SiNx/SiO2/SiNx are optimized. Ultimately, the well-formed, residue-free via-holes are obtained and the bad issue occurred in the via-hole is completely improved, which provide theoretical guidance for favorable electrical contact with the oxide TFT devices.