4-Mask工艺Cu腐蚀分析及改善研究

针对4-Mask工艺铜数据线腐蚀造成的锯齿状不良现象进行系统研究,发现铜腐蚀发生的工艺步骤和机理,并找到有效的措施。首先,通过显微镜对每道刻蚀工艺后铜数据线形貌进行观测,确定铜腐蚀发生的工艺步骤。接着,通过扫描电子显微镜和X射线电子能谱测量腐蚀生产物成分,对腐蚀机理提出合理解释。最后在铜腐蚀发生机理基础上,提出有效的改善措施。铜腐蚀是在有源半导体层干刻和光刻胶的灰化综合作用下发生,其主要产物为氧化铜、氯化铜。通过先进行灰化工艺然后进行有源半导体层干刻的工艺措施,在铜数据线两侧形成氧化铜保护膜,可以彻底改善铜腐蚀。改善措施可以解决铜腐蚀的问题,彻底消除铜数据线锯齿状不良。

Research of Cu corrosion in 4-Mask process

The jagged defect of copper data lines caused by corrosion of copper in 4-Mask process was investigated systematically, the steps and mechanism of copper corrosion were found, and the effective measures to improve copper corrosion were established. Firstly, the morphology of copper data lines after each etching process was observed by microscope to determine the process steps of copper corrosion. Then, the composition of corrosion products was confirmed by scanning electron microscopy (SEM) and X-ray electron spectroscopy (EDS), and the corrosion mechanism was explained reasonably. Finally, based on the mechanism of copper corrosion, effective improvement measures were put forward. Copper corrosion occurs under the combined action of a-Si dry etching and photoresist ashing, and the main products of copper corrosion are CuO and CuCl₂. CuO protective film is formed on both sides of copper data line by ashing process first and then a-Si dry etching,so copper corrosion can be completely improved. The improvement measures can solve the problem of copper corrosion and eliminate the jagged defect of copper data lines.