Radiation thermometer and wafer thermometry manner null for wafer thermometry

摘要

PURPOSE:To measure the temperature on the surface with high accuracy by a method wherein the influence of a plasma is reduced to a minimum by using an optical filter which passes only infrared rays at a wavelength which is not transmitted through the wafer. CONSTITUTION:Infrared rays which have been radiated form a measuring face 8 are incident on the inside of a quartz round rod 2 from a photodetection face 2a and are propagated up to the other end 2c while they are being reflected totally on a side-wall 2b. A sheath tube 5 functions to shut off the infrared rays which are incident from the side face of the quartz round rod 2 and to eliminate their influence. The transmitted infrared rays at a wavelength which is not passed through a wafer are passed through an interference filter 3; after that, they are incident on an infrared detector 4. An electric current which is proportional to their intensity is generated; and is amplified by an amplifier 6 and converted into a temperature value by using an operation device 7.