光刻制程参数对光刻胶DICD和锥角的影响

光刻胶经过曝光、显影后的锥角(Taper)和关键尺寸(Develop Inspection Critical Dimension,DICD)是光刻工艺的重要参数。明确影响锥角和DICD的工艺参数,进而控制锥角和DICD,这对工艺制程至关重要。本文结合光刻制程,探究了光刻胶厚度、曝光剂量、Z值、显影时间对锥角和DICD的影响,并结合蒙特卡罗算法对显影制程进行评估。实验结果表明:光刻胶厚度每增加1μm,DICD增加约2.6μm。同时,厚度增加会导致光刻胶顶部的锥角逐渐由锐角向钝角演变。曝光剂量每增加10mJ/s,DICD则减小约0.8μm,锥角则呈阈值跳跃式上升趋势。基板在最佳焦平面曝光,DICD和锥角均一性最好。显影时间每增加10s,DICD下降约0.3m,锥角则增加约1.7°。最终,DICD和锥角呈负相关关系,可以通过调节光刻工艺参数对锥角和DICD进行控制。

Influence of lithography process parameter on DICD and taper of photoresist

The Taper and DICD(Develop inspection critical dimension) after exposure and development are important parameters in lithography process, which determine the TFT pattern and TFT characteristic. Therefore, it is necessary to identify the process parameters affecting Taper and DICD in mass production, aiming at making Taper and DICD under control, which would improve production yield. In this paper, the effects of photo resist thickness, dose and Z value in exposure,development time were comprehensively studied. What's more, Monte Carlo algorithm was used to evaluate the development process. The experimental results show that photo resist thickness increases by about 1 μm, DICD will increase by about 2.6 μm. At the same time, the increase in photo-resist thickness causes the taper on the top of photoresist gradually to evolve from an acute angle to an obtuse angle. For every 10 mJ/s increase in exposure dose, DICD is reduced by about 0.8 μm, and taper rise in a threshold. The uniformity of DICD and taper is the best when the substrate is exposed at the best focal plane. For every 10 s increase in development time, the DICD decreases by about 0.3 μm and the Taper increase by about 1.7°. In the end, DICD and Taper are negatively correlated, it is possible to make profile and CD Bias under control by adjusting the process parameters.