薄膜晶体管光刻制程中，光刻胶光刻平面位置是决定光刻图形质量的关键因素。为了在光刻机最小分辨率条件下改善光刻图形质量，本文从光刻胶内反射光线的反射特点出发，以减小光刻胶内反射光线对非光刻区域的光刻光强及增加光刻区域的光刻胶底部光刻光强为基础，推导出光刻光线倾斜入射光刻胶平面时，光刻胶光刻平面位置调整量的计算公式，并以该公式计算出的调整量对光刻胶光刻平面进行调整。结果表明：对于最小分辨率为3.0 μm 的投影光刻机，进行线间距为2.2 μm 的产品光刻时，以该公式计算出的调整量对光刻胶光刻平面调整后，较未调整前，光刻图形坡度角提升了13.3%，光刻胶线宽或线间距宽度(DICD)均一性改善了14.7%，光刻图形光刻胶残留得到解决。

In the lithography process of thin film transistor, the lithography plane position of photoresist is the key factor that determine the quality of lithography pattern. In order to improve the quality of lithography pattern under the minimum resolution of lithography machine, the reflection characteristic of the light in the photoresist is studied in this paper, based on reducing the intensity of the reflected light in the photoresist on the non-lithography region and increasing the intensity of the photoresist at the bottom on the lithography region, the computational formula for the lithography plane position adjustment of the photoresist is deduced under the oblique incidence. The adjustment amount is calculated by the formula and the lithography plane is adjusted by the adjustment. The results show that for the projection lithography machine with the minimum resolution of 3.0 μm, and for the product with the line space of 2.2 μm, after adjusting the lithography plane of photoresist with this adjustment，the slope angle of the lithography pattern is increased by 13.3%，and the uniformity of the DICD (development inspection critical dimension) is improved by 14.7%，the photoresist remain of the lithography pattern is resolved.