MASK MATCHING EVALUATION PATTERN AND EVALUATION METHOD FOR MASH ALIGNMENT ACCURACY

摘要

PURPOSE:To enhance the visibility of the mask matching evaluation pattern for judgement of matching deviation based on the principle of a vernier by supposing the upper layer side pattern and the lower side layer pattern, and to facilitate the judgement of matching accuracy. CONSTITUTION:The optical path difference for an incident light is generated between the left and the right sides of the overlapped parts A to J to be formed on the edge part of graphic patterns 4a to 4f and 6a to 6e which constitute the upper layer side pattern 6 and the lower layer side pattern 4 on a substrate. For example, when a rectangular graphic patterns 2a to 2f, consisting of an SiO2 layer, are provided on the Si substrate 1 as a light path difference generating pattern 2, a stepped part is generated on the SiO2 layer insulating film 3 to be formed on the Si substrate 1 and the film thickness W1 and W2 of the entire SiO2 layer are periodically changed. As a result, different interference color appears on the overlapped parts A, C, E, G, and I, and B, D, F, H and J, and both of them can be identified easily. Instead of the change of film thickness, the change of refractive index may be used.