Patent ID: 8197634

Claim:
A plasma processing apparatus for turning a gas supplied to a vacuum reactor into plasma and etching a surface of a sample to be processed placed in the vacuum reactor by the plasma, the apparatus comprising: a vacuum reactor; a vacuum evacuation means for evacuating the interior of the vacuum reactor; a sample stage means disposed in the vacuum reactor for placing a sample to be processed; a material gas introducing means for introducing material gas into the vacuum reactor; a plasma generating means for turning the gas introduced via the material gas introducing means into plasma; and a plasma emission detecting means disposed at a plane opposing to the sample to be processed, wherein the plasma emission detecting means further comprises; an emission extraction means for extracting the emission from plasma; a light transmission means located outside of the vacuum reactor for scattering and transmitting incident light into the emission extraction means; and a vacuum partition window configured to prevent the light transmission means from being directly exposed to the plasma, wherein the light transmission means of the plasma emission detecting means is comprised of a light scattering means having an uneven surface of Ra 5 μm or greater and Ra 200 μm or smaller, for scattering and transmitting incident light of 0.2 μm or greater in wavelength; wherein the uneven surface of the light scattering means is obtained by applying an abrasive to the surface of the light scattering means.