| 摘要 |
PURPOSE:To efficiently eliminate heat wave from pattern-exposing light for prevention of slippage of pattern due to thermal expansion, by providing inside of an optical system with a filter device for passage of a liquid which is highly capable of absorbing heat wave. CONSTITUTION:Light emitted from a light source, such as a xenon mercury discharge lamp, etc. is reflected by a reflecting shade 2 and a reflecting board 3 before entering a shutter 4. The light having passed the shutter 4 enters a filter device 5 which is made of a light-pervious material. The filter device 5 is provided with a cabinet-like body 5a, a liquid inlet 5b and a liquid outlet 5, and this filter is provided for passage of nickel sulphate solution which is highly capable of absorbing infrared rays. The light, whose heat ray has been thus absorbed, reaches a photomask 9 passing through a fly eye lens 6, the reflecting board 7 and a lens 8, and then, it is exposed to a semiconductor wafer 10. As the heat wave has been almost eliminated from the light by having been thus absorbed, temperatures of the mask and the wafer do not rise high, and therefore, it is possible to minimize slippage of the pattern. |
