Numerous alternate processes are under industry-wide evaluation as simplifications to current double patterning methods. Reduction in process complexity and cost may be achieved by use of photoresist stabilization methods that eliminate one etch step by allowing a second resist to be patterned over the first resist pattern. Examples of stabilization methods using numerous curing processes have been reported. At least some resist shrinkage during stabilization appears to be generally observed for these methods. We evaluate the link between volumetric shrinkage and threedimensional pattern distortion for a variety of resist geometries using experimental and simulation-based methods. Experimental resists designed for double patterning using 172 nm UV resist curing were evaluated and showed shrinkage of less than 10 percent. Several simplified metrology approaches for measuring shrinkage as well as inferring shrinkage distortions were assessed. For top-down SEM measurements, elbow inner corner rounding measurements appear to be a usefully robust method for estimating shrinkage distortion. Finite element analysis of resist structures yields shrinkage distortions that are in good qualitative and quantitative agreement with experiments, and thus appears to provide a provisionally general and useful method for predicting pattern distortions that arise during cure-based resist stabilization methods used in double imaging.

Date Published: 1 April 2009
PDF: 8 pages
Proc. SPIE 7273, Advances in Resist Materials and Processing Technology XXVI, 727309 (1 April 2009); doi: 10.1117/12.814474

Published in SPIE Proceedings Vol. 7273:
Advances in Resist Materials and Processing Technology XXVI
Clifford L. Henderson, Editor(s)