METHOD FOR MEASURING OVERLAY

摘要

PURPOSE: A method for measuring an overlay is to provide an excellent image state, by capturing images regarding the first and second main scales in X and Y directions and in different focusing, and by capturing an image of a vernier in a focusing different from those of the main scales. CONSTITUTION: A pair of the first main scales(10) and a pair of the second main scales(20) having a step are symmetrically disposed in X and Y directions of a structure of a semiconductor substrate to form an outer box. An upper layer(22) of which the surface is planarized is formed on the structure having the outer box. The vernier(30) of an inner box type for measuring the overlay is formed on the upper layer corresponding to the outer box region. An interlayer overlay is measured by an image focusing process using an overlay mark regarding the vernier and the first and second main scales.