光刻胶段差对光刻图形的影响与改善

TFT光刻制程中,光刻胶段差使光胶在同一个光刻平面上,各区域的光刻程度不同,严重影响着光刻图形的质量。文章从光刻胶段差对光刻图形影响的原因进行分析,根据光强在投影光刻机光刻系统中焦点附近与光刻胶内部的变化特点,推导并计算出光刻胶段差区域内光强变化量为零时,光刻系统中光刻平面所应处于的位置,同时结合当前光刻系统焦平面的位置,计算出光刻平面的调整量,并以该调整量对当前光刻平面进行调整。结果表明:对于极限分辨率为2.41μm的投影光刻机,要使厚0.52μm的光刻胶段差内光强变化量为零,光刻平面调整量为9.434 42μm,且对光刻平面调整后10μm后,在DICD(Develop Inspection Critical Dimension)变化量较小的情况下,可显著改善沟道长为2.5μm的GOA(gate drive on array)区域的光刻胶残留。

Effect of segment difference of photoresist on lithography pattern and improvement

In the TFT lithography process, the segment difference of the photoresist make the lithography level of the each region of the photoresist be different on the same lithography plane, which seriously affect the quality of the lithography pattern. In this paper, the reason for the effect of the segment difference of photoresist on the lithography pattern is analyzed. Based on the characteristics of the light intensity change near the focal point of the lithography system of the projection lithography machine and the internal of the photoresist, the position of the lithography plane in the lithography system is calculated when the light intensity change is zero in the area of the segment difference of the photoresist. Combining with the position of the current focal plane in the lithography system, the adjustment amount of the lithography plane is calculated, and the current lithography plane is adjusted by the adjustment amount. The results show, for the projection lithography machine of the 2.41 μm limit resolution, if the light intensity change of the 0.52 μm segment difference of the photoresist is zero, the lithography plane need to adjust 9.434 42 μm. By adjusting 10 μm for the lithography plane, the change amount of the DICD(Develop Inspection Critical Dimension)is little, but for the GOA (gate drive on array) channel which length is 2.5 μm,the improvement of the photoresist remain is significant.