Modeling and Prediction of Line Pattern Collapse
In semiconductor manufacturing, effective cleaning of structures with liquid is one of the most important and potentially difficult process steps. It is important because it remains the cheapest and most cost-effective method to remove particles and residues from the structures in order to prevent defects, but can also be difficult because as the structures dry, surface tension forces can cause the features to permanently deform and stick to each other or even break. Experimental testing of structures is important, but generation of the smallest structures can only be done using expensive lithographic techniques. Because of this there is a strong financial incentive to be able to accurately model these structures and predict whether they will collapse due to capillary forces. Modeling and prediction of this phenomenon has traditionally been done using the Euler-Bernoulli Beam Equation, but this method requires several assumptions that considerably limit its accuracy and usefulness as a predictive technique. These limitations are overcome by substituting the 1D Euler-Bernoulli Beam Equation with a 2D finite element simulation in COMSOL Multiphysics.