摘要:
A method is described for alignment of a substrate during a double patterning process. A first resist layer containing at least one alignment mark is formed on the substrate. After the first resist layer is developed, a second resist layer is deposited over the first resist layer, leaving a planar top surface (i.e., without topography). By baking the second resist layer appropriately, a symmetric alignment mark is formed in the second resist layer with little or no offset error from the alignment mark in the first resist layer. The symmetry of the alignment mark formed in the second resist can be enhanced by appropriate adjustments of the respective thicknesses of the first and second resist layers, the coating process parameters, and the baking process parameters.