| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical element holding technology capable of controlling variance in optical characteristics of rotational asymmetry, where the variance is caused by light passing through an optical element with a light quantity distribution of rotational asymmetry. SOLUTION: A lens holding member 33 holds a lens 32 which is placed at a position that for an exposure light to pass through in a radiated region 38 almost in a rectangular shape like an optical element placed near a reticle or a wafer in an exposure unit of a scanning exposure type. Roll offs 33d, 33e are formed at two spots between which the radiated region 38 on an inner side facing the outer surface of the lens 32 is sandwiched along the direction of its shorter side. In the lens holding member 33, thermal conductivities of the roll offs 33d, 33e are low in comparison with other regions 33b, 33c, and the distribution of the thermal conductivity is of rotational asymmetry. Therefore, even if the radiated region 38 is of rotational asymmetry, thermal deformation of the lens 32 becomes more rotationally symmetric, and the variance in optical characteristics of rotational asymmetry is controlled. COPYRIGHT: (C)2005,JPO&NCIPI
|
