VIEW PORT, VIEW PORT WITH LIGHT SOURCE, TRANSMISSION- CONDITION-MEASURING DEVICE FOR VIEW GLASS WINDOW, PLASMA MONITOR DEVICE AND METHOD FOR PLASMA TREATMENT

摘要

PROBLEM TO BE SOLVED: To provide a view port, a view port with light source, a transmission condition measuring device for a view port glass window, a plasma monitor device and a method for plasma treatment with which influence of variation of light transmittance of the glass window varying every hour through a plasma process is compensated in real time, and a plasma condition is monitored without being affected by variation with time of the glass window. SOLUTION: A view port 70 is constituted by providing first and second glass windows 74 and 75 to a cylinder body 72 fitted to a chamber 20. The first and second glass windows 74 and 75 are placed in face to face with each other so that the light is transmitted from the first glass window through the second glass window.