TFT-LCD制造工艺中金属或金属复合膜层坡度角的研究

在薄膜晶体管液晶显示器(TFT-LCD)面板制程中,Gate层(栅极)电路和SD层(源极)电路根据产品电阻等要求可以使用纯金属膜层,如钼、铜等金属膜层,也可以使用金属复合膜层,如铝钼、铝钕钼、钼铝钼等金属复合膜层。当使用不同金属或金属复合膜层作为Gate、SD电路时,应当对应不同的刻蚀液。但在实际生产时,往往是一种刻蚀液同时对应金属膜层或金属复合膜层。由于钼金属膜层的Etch Rate(刻蚀速率)大于铝钼等金属复合膜层Etch Rate,所以当铝钼等金属复合膜层刻蚀完成后对应坡度角有时会存在异常,如膜层角度较大(80～90°)、顶层金属钼发生尖角或缩进等现象,产生宏观不良及进行后工序时会产生相应的光学不良或导致后层物质残留,影响产品品质。本文针对金属膜层或金属复合膜层坡度角进行影响因素分析,主要受刻蚀工序及曝光工序影响。通过对刻蚀液浓度调整、温度调整、刻蚀方式调整及曝光工序等调整减少金属钼发生尖角、缩进几率,将金属膜层坡度角控制在60°左右及金属复合膜层坡度角控制在50°左右,从而降低不良的发生率,提高产品品质。

TFT-LCD manufacture technology metal or metal composite film layer profile

In the thin film transistor liquid crystal display (TFT-LCD) panel process, Gate(grid) layer and SD layer (source) circuit can use pure metal film layers according to the product requirements, such as molybdenum, copper and other metal film, can also use metal composite film layers such as aluminum molybdenum, aluminum neodymium molybdenum, molybdenum aluminum molybdenum metal composite film. When different metal or metal composite layers are used as Gate and SD circuits, different etchant should be applied. But in actual production, it is often an etchant which corresponds to the metal film layers or metal composite film layers. The molybdenum metal film layers etch rate is larger than the aluminum molybdenum composite film layers etch rate. When the aluminum molybdenum composite film etching complete, the profile is abnormal sometimes, such as film larger angle (80~90°), top metal occurs tip or shrink phenomenon. When the macro defect occurs and the subsequent process will produce the corresponding optical defects or lead to residual material in the rear layer and affect the quality of products. In this paper, the factors affecting the profile of metal film layers or metal composite film layers are mainly affected by the etching process and exposure process. Through adjusting the etchant concentration, temperature, etching mode and exposure step to adjust the angle, the metal molybdenum occurrence probability of the metal film indentation is reduced, the slope angle of the metal film is controlled at 60°, and the metal composite film slope angle is controlled at 50° so as to reduce the bad incidence and improve the product quality.