CLEANING OF INTERNAL OBSERVATION WINDOW FOR APPARATUS UTILIZING PLASMA

摘要

PURPOSE:To enable removal of a plasma product adhering to a window while a thin film working or the like is carried on, by irradiating an observation window of a plasma equipment in operation with a laser beam that has limited absorption by a window material of the observation window. CONSTITUTION:Absorption energy of a plasma reaction product 13 is about 0.1-0.5eV as adhering to an internal observation window 12 of an equipment utilizing plasma. The window 12 is irradiated with a laser beam that has limited absorption by a window material thereof from a laser beam oscillating section 1 through a scanning section 8. s a result, the plasma reaction product 13 absorbs a part of the laser light and a photochemical reaction is caused by the energy thereof to remove the product 13 by decomposition and volatilization thereof. This enables the removal of the plasma product 13 on the observation window 12 while a thin film working or the like is carried on with a plasma apparatus 10 thereby increasing the operating rate of the apparatus significantly.