Modeling Planarization With Polymers

Abstract

When a patterned surface is coated with a polymer solution and dried or cured, the resulting surface is not completely flat (contrary to most drawings illustrating the planarization layer in multilayer resist schemes.) In order to understand the thickness variation of the polymer film, it is useful to define local planarization as the reduction in height of a single step and global planarization as the long range effects of different pattern densities. It has been determined that the efficiency of planarization depends on the thickness of the polymer coating, the shrinkage of the polymer solution, the flow properties of the polymer during the cure cycle, and the dimensions of the patterns on the surface. The degrees of both local and global planarization can be predicted by straightforward calculations.