| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that a foil slacks and the transmittance of a foil trap to EUV light is lowered when the foil trap is designed in a large size and the length of the foil increases.SOLUTION: A truncated conical comb-shaped intermediate ring 6 which has a center axis coaxial with the principal axis of the foil trap 5 and a cut-in portion 6a with which a foil 5a is engaged is secured to the foil trap 5, and the foil trap 5 is supported by the intermediate ring 6 so as not to slack. The side surface of the truncated conical shape is configured to be parallel to an EUV light beam from a high-temperature plasma P which passes over the neighborhood of the side surface, and does not intercept the EUV light. When the comb-shaped intermediate ring is supported by a spoke for joining a center support pole 5b of the foil trap 5 and an outside ring 5c, the center axis of the comb-shaped intermediate ring 6 is not displaced out of the principal axis of the foil trap. |
