Verification of Guide Patterns

Guide patterns (GPs) are very critical in contacts (and vias) patterning in directed self-assembly lithography (DSAL). Simulations may be used to verify whether each GP will lead to correct patterning of its member contacts, but runtime is excessive. Instead, the shape of GP can be characterized using some geometric parameters. Then, a function for the verification can be constructed to predict whether the required contacts can be obtained by a GP (Shim et al., Proceedings for SPIE Advanced Lithography, pp. 1–8, 2015, [1], Azat, Proceedings for SPIE Advanced Lithography, pp. 1–10, 2013, [2]). Specifically, each GP in a test set is represented as a vector in parameter space; DSA simulation is applied to each GP assessing its acceptability, and corresponding vector is marked “good” or “bad” accordingly; the parameter space is deformed in a way that a radial distribution is converted into one in which the good and bad vectors can be successfully separated by a certain hyperplane , which finally becomes the verification function. It is also shown that principal component analysis (PCA) can be applied for reducing the dimensionality of the parameter space, and the characterization of GPs can be generalized to allow different types of GP to be verified in a unified fashion. Such methods are demonstrated in 10 nm technology.