Fitzpatrick, Cella, Harper & Scinto
Method for forming thin film
 In a method for forming a multi-layer optical thin film on a surface of a base material, a multi-layer optical thin film is formed based on thickness setting values for respective layers, an optical characteristic of the thus formed multi-layer optical thin film is measured, thicknesses for the respective layers for a multi-layer optical thin film to have an aimed optical characteristic are obtained based on the thus measured optical characteristic, the thickness setting values are corrected based on the thus obtained film thicknesses for the respective layers, and a next multi-layer optical thin film is formed based on the thus corrected thickness setting values. In another method for forming a thin film by sputtering, a concentration of H.sub.2 O gas in a vacuum chamber or a discharge impedance is measured, and at least one of sputter power, sputter gas partial pressure, and sputter gas flow rate is controlled in accordance with the measurement result so as to keep the sputtering rate constant. 
Canon Kabushiki Kaisha
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Kenji Yasuyuki Ryuji
Ando Suzuki Biro