Lithographic Optimization

Lithographic Imaging Equation

1. Image Transfer 
Position steepest slope (inflection point) of the aerial image at the feature edge

 

  


2. Dissolution Contrast
Maximize dissolution change with dose through R(m) analysis of photoresists

 





3. Dissolution Threshold
Position the dissolution threshold at the inflection point of the image with developer concentration

 

R = Dissolution rate
x = Horizontal position
m = Relative PAC concentration
gR = Resist contrast
x* = Nominal edge of resist features