TDDI产品Mo-Al-Mo膜层腐蚀原因分析及改善

为降低TDDI产品Lead Open型线不良发生率,本文对Lead Open的发生机理进行了研究及改善验证。对TDDI产品生产数据进行了对比,对Mo-Al-Mo结构的SD膜层进行研究,根据以上结果确定改善方案并投入验证。首先,明确了Lead Open发生率与Delay Time的关系。接着,对SD膜层的微观结构进行了表征。然后,根据膜层结构和不同金属的电化学特征,建立了SD膜层电偶腐蚀模型。分析表明:Mo、Al两种金属间存在1.47V的电极电位差,具有很强的电偶腐蚀倾向性,且表层Mo中存在10nm级别的贯穿性孔洞,直径为0.4nm的水分子可轻易渗入,进而引发电偶腐蚀。表层Mo厚度增加25%后,其腐蚀速度较量产条件降低30%,Lead Open发生率降低1.4个百分点,维持在0.1%的较低水平,满足TDDI产品量产对该类不良发生率的要求。

Analysis and improvement of Mo-Al-Mo film corrosion in TDDI products

In order to reduce the incidence rate of Lead Open-type line defects in the TDDI products, the mechanism of the Lead Open was studied and validated. Meanwhile, the improved solution for the defects was determined and put verification based on the results coming from the TDDI production data comparison and the investigation on SD film of the Mo-Al-Mo structure. Three parts of the whole research process were contained. The relationship between the Lead Open incidence and Delay Time was firstly determined, and then the microstructure of SD film was characterized. Finally, according to the electrochemical property and film structure of different metals, a galvanic corrosion model of SD film was also established. The results show that a potential difference (PD) of 1.47 V exists between Mo and Al, and the PD has a strong galvanic tendency. In addition, some penetrating holes with the size of~10 nm are found in the Top Mo, which can be easily infiltrated by water with the size of~0.4 nm and thus leading to the galvanic corrosion. Nevertheless, compared to the existing production conditions, the corrosion rate can decrease by~30% when adding~25% Top Mo. More importantly, the incidence rate of Lead Open is found decrease by 1.4% and maintain the low level of 0.1% at this time, which meets the requirement for the defect incidence rate of the TDDI products.