| 摘要 |
PURPOSE:To minimize the reflection factor in the excimer laser wavelength by laminating intermediate refractive index substance layers being the first and the third layers, and low refractive index substance layers being the second and the fourth layers in said order on a base body, and specifying the refractive indexes of the intermediate refractive index substance and the low refractive index substance. CONSTITUTION:An intermediate refractive index substance layer 2 of the first layer, a low refractive index substance layer 3 of the second layer, an intermediate refractive index substance layer 4 of the third layer, and a low refractive index substance layer 5 of the fourth layer are laminated in said order on a base body 1 for allowing a light beam whose wavelength is >=160nm to pass through, by which a reflection preventive film used for an optical system using an excimer laser. Also, in a wavelength area of >=160nm, a refractive index of the intermediate refractive index substance and a refractive index of the low refractive index substance are set to 1.6-1.8, and <=1.5, respectively. In such a way, with respect to the excimer laser wavelength being an exposing light of a stepper, a reflection preventive film having a satisfactory reflection preventive effect is obtained. |
