Apparatus for monitoring in-situ the thickness of a film during film deposition and a method thereof

摘要

A film deposition apparatus and a method thereof for accurately forming a film of a given thickness on the surface of a wafer is described. The film deposition apparatus includes a laser beam to perform a precise in-situ monitoring of a change in thickness of the film being deposited on the surface of the wafer. An optical guide is provided in an attachment coupled to the quartz furnace of a chemical vapor deposition apparatus. A laser beam is introduced into the quartz furnace through the optical guide, and is projected onto the wafer. The laser beam reflected by the wafer is channeled through the same optical guide to be discharged to the outside of the quartz furnace. A change in thickness of the film is monitored based on the strength of the reflected laser beam. In this manner, the laser beam can be transmitted without passing through the wall of the quartz furnace, and the thickness of the film can be accurately monitored without the process being affected by the thin film deposited on the internal wall of the quartz furnace.