The endpoint detection method using moiré pattern in CMP’s EPD system

Abstract

We have developed a technique for observing fine wiring patterns using moiré patterns generated by interference between wiring patterns and reference patterns in endpoint detection (EPD) of the CMP. With this technique, wiring pattern images of patterned wafers can be evaluated with a simple and low magnification optical system to observe large moiré patterns. In this process, the large moiré pattern is calculated from the device wiring and other reference pattern layouts. As a result, EPD signals can be detected.