Mo/Al/Mo结构电极的坡度角和关键尺寸差研究

Profile and critical dimension bias of Mo/Al/Mo electrode

Mo/Al/Mo结构金属作为TFT的电极,刻蚀后的坡度角和关键尺寸差是重要的参数。明确影响坡度角和关键尺寸差的工艺参数,进而控制坡度角和关键尺寸差,这对工艺制程至关重要。本文探究了膜层结构、曝光工艺、刻蚀工艺对坡度角和关键尺寸差的影响,并对刻蚀工艺进行正交试验设计。实验结果表明:Al膜厚每减小60nm,坡度角下降约9°,关键尺寸差增加0.1μm。曝光工艺中,显影后烘烤会增加光阻粘附力,导致关键尺寸差减小0.1μm,同时坡度角增加约9°。刻蚀工艺中,过刻量每增加10%,坡度角下降3.3°,关键尺寸差增加0.14μm;正交试验结果表明,对关键尺寸差、刻蚀均一性、坡度角影响因素的重要性顺序是:液刀流量>Air Plasma电压>水刀流量。经上述探究表明,坡度角和关键尺寸差呈负相关关系,刻蚀程度增加,关键尺寸差增加,而坡度角则减小。可以通过调节工艺参数对坡度角和关键尺寸差进行控制。

At present,Mo/Al/Mo structural film is electrode material in TFT-LCD industry due to its advantages.The Critical Dimension Bias which is short for CD Bias and the Profile of Mo/Al/Mo electrode after etch process are important parameters which determine the TFT pattern and TFT characteristic.Therefore,it is necessary to identify the process parameters affecting profile and CD Bias in mass production,aiming at making profile and CD Bias under control,which would improve production yield and quality.In this paper,the effects of film structure,photo condition and etch condition on profile and CD Bias are comprehensively studied.What＇s more,orthogonal design for wet etch condition is conducted,which makes it possible to understand the order of importance for wet etch process parameters.The experimental results show that aluminum film thickness decreases by about60 nm,profile will decrease by about 9°and CD Bias will increase by 0.1μm at the same time.When itcomes to photo condition,hard bake after developing process would enhance the adhesion between photo resist（PR）and metal.They will make CD bias decrease by about 0.1 um and profile correspondingly increase by about 9°.The over etch degree increases by 10%,profile will decrease by about 3.3°and CD Bias will correspondingly increase by about 0.14μm.The results of the orthogonal test show that the order of importance affecting CD Bias,profile and uniformity is as follows：Chemical Knife flow 〉Air plasma（AP）voltage〉 DI water Knife flow.Through the above research,it is found that profile and Bias are negatively correlated：The profile will decrease and CD Bias will increase when over etch degree increases.It is possible to make profile and CD Bias under control by adjusting the process parameters.