Spin etcher with thickness measuring system

Abstract

A spin etcher with a thickness measuring system includes a rotatable spin head, etchant supply means, and etchant supply controller. A substrate is mounted upon the spin head. The etchant supply means is disposed over the substrate, and sprays an etchant onto the substrate. The etchant supply controller controls the etchant supply. The spin etcher further includes a main controller for transferring an etchant supply stop signal to the thickness measuring system and the etchant supply controller. The thickness measuring system allows a light to impinge on a surface of the substrate, and analyzes an interference signal of the light reflected from the substrate to measure a thickness of a thin film. The main controller compares a result measured by the thickness measuring system with a reference value, and transfers the etchant supply stop signal to the etchant supply controller before the measured result reaches the reference value. During a predetermined time after the etchant supply is stopped, the thin film is etched one more time by an etchant remaining on the substrate. As a result, the thickness of the thin film reaches the reference value.