为了适应LTPS TFT LCD显示屏超高分辨率极细布线的趋势，降低LTPS TFT层间绝缘层过孔刻蚀带来的良率损失，提高产品品质，本文研究了LTPS TFT层间绝缘层过孔刻蚀的工艺优化。实验以干法刻蚀为主刻蚀，湿法刻蚀为辅刻蚀的方式，既结合干法刻蚀对侧壁剖面角及刻蚀线宽的精确控制能力，又利用了湿法刻蚀高刻蚀选择比的优良特性，改善了层间绝缘层刻蚀形貌，减少干法刻蚀对器件有源层的损伤，避免有源层被氧化，防止刻蚀副产物污染开孔表面。实验结果表明，干法辅助湿法刻蚀能基本解决刻蚀过程中过刻、残留的问题，使得层间绝缘层过孔不良良率损失减少73%以上，且TFT源漏电极接触电阻减小约90%，器件开态电流提升约15%。干法辅助湿法刻蚀是一种优化刻蚀工艺，提升产品性能的新方法。

In order to adapt to the trend of ultra-high resolution and extremely fine wiring of LTPS TFT LCD display, reduce the yield loss generated by via etching process of LTPS TFT interlayer dielectric, and improve the production quality, the process optimization of via etching process of LTPS TFT interlayer dielectric was investigated. The experiments were based on dry etching as the main etching step assisted with wet etching. It not only conbined with the excellent control of profile and feature size of dry etching but also got high etching selectivity of wet etching. The experiments also aimed at reducing the damage and defects reduced by dry etching and avoiding pollution of the hole surface by etching by-products. Experimental results indicated that dry etching assisted with wet etching basically solved the problems of over etching and etching residual, reduced the yield loss of via etching defect rate by 73%. And contact resistance reduced by about 90%, ON-state drain current raised 15% of the dry etching. Therefore dry etching assisted with wet etching is an innovative method to optimize the via etching process and promote product performance.