METHOD FOR POST-TREATMENT OF THIN FILM, POST-TREATMENT DEVICE, POST-TREATED OPTICAL MEMBER AND ALIGNER PROVIDED WITH OPTICAL MEMBER

摘要

PROBLEM TO BE SOLVED: To solve the problem of drastic decrease of transmittance of a pure crystal of metal fluoride, which originally exhibits excellent transmitlance to an F2 eximer laser beam, caused by thin film forming with a general thin film forming method such as vacuum deposition or sputtering and to solve the problem of the decrease of transmittance in optical members such as a lens or a prism resulting therefrom. SOLUTION: The post-treatment method contains a housing step in which a fluoride thin film with a fluorine defect film formed on a substrate is placed in a fluorine atmosphere at a specifically controlled temperature and a time measuring step for measuring the time consumed to raise temperature from the specific temperature so as to replenish the fluorine defect with fluorine.