| 摘要 |
PURPOSE:To obtain always constant exposing line width by arranging a mirror depending upon the wavelength of irradiated light and having the characteristic of selective reflection between a reticle and a projection lens. CONSTITUTION:Light from an illumination light source lamp 2 is divided into two parts by a translucent mirror 11 and then reflected by mirrors 12, 13 respectively to illuminate the reticles 1, 10. Filters are arranged on the passages of the two-divided light rays to select the wavelength of light to be irradiated to the reticles 1, 10 and the reticles 1, 10 are irradiated by light rays having different wavelength respectively. The two reticles 1, 10 can be arranged on the optimum positions respectively in accordance with the exposed wavelength. Even if light rays having different wavelength are superposed by a projection lens 4, a clear circuit pattern can be exposed without lossing its resolution. |
