METHOD FOR ALIGNING A SEMICONDUCTOR WAFER

摘要

Alignment marks (1) in X- and Y-direction are measured in different layers of a semiconductor wafer (2) using a different filter (5) or algorithm for each direction measurement as well as a different template signal (4) in order to retrieve displacements to be corrected by an alignment. Thus, separate requirements provided by different layers (10, 11) on a wafer (2) concerning overlay accuracy in diffferent directions can be fulfilled. Shorts or missing contacts in designs patterns with small tolerances can be avoided efficiently. Moreover, combining those alignment marks (1, 1') from two different critical layers into one localized alignment structure (30), alignment time is advantageously saved.