Pattern-size effect on electron shading

The effect of pattern size on electron shading over a line-and-space photoresist pattern on a MOS capacitor was determined by a numerical simulation. It was found that it takes longer for the potential field to attain the steady state as the pattern shrinks and that the steady-state electron shading is independent of pattern size; that is, the potential field is linearly scalable. We also revealed that the gate-voltage change can be easily analyzed by a simple electric circuit model. Moreover the capacitance between the gate electrode and the line-and-space photoresist lines can be estimated by a simple geometrical approximation.