Method for controlling film thickness

Abstract

Abstract PURPOSE:To control an optical film thickness of a film with good accuracy by sampling the change of the transmittivity or reflectivity of a monitor substrate with time, determining quadrative regression functions and setting the target vapor deposition time of the film based on the value obtd. CONSTITUTION:An evaporating material sticks to monitor glass 5 as well when the vapor deposition to the substrate 3 is started. The monitor glass 5 is projected by a light emitted by a light projecting part A and only the quantity of the light of the specific wavelength filtered from the light transmitted through the monitor glass 5 by an interference filter 10 is measured by a light receiving element 11. The measured intensity of the transmitted light is converted to an electric signal which is then read as the value of the intensity of the light into a computer 15 by an AD converter 13 and an I/O interface 14. The quadratic regression functions are successively determined in accordance with the equation by using the sampling data obtd. in such a manner and the target vapor deposition is set based on the point of the time when t=tp is attained. More specifically,a signal is emitted through the I/O interface 16 at the time of t=tp to close a shutter 18 and to interrupt the evaporation from a vapor source 19. The film thickness is controlled with the high accuracy by the above- mentioned method. The film thickness control may also be executed by utilizing the reflectivity.

Inventors

• 👤 Yoshiyuki Hanada
• 👤 良幸 花田
• 👤 Etsuo Ogino
• 👤 悦男 荻野
• 👤 Katsuhisa Enjoji
• 👤 勝久 円城寺
• 👤 Kazuhiko Fujimaki
• 👤 藤巻　和彦

Bibliographic Details