| 摘要 |
An illumination optical apparatus (IOA1) and an exposure apparatus (EA1) having same, that reduces coherence in the illumination light beam, which in turn eliminates illumination non-uniformities at the mask (13) and wafer (17). The illumination apparatus comprises, in order along an optical axis (AX), a coherent light source (1) capable of generating a first light beam (b1) having a coherence length, the light beam being directed along a first optical path. Further included is a depolarizer (3) and a first optical delay element (4). The latter is capable of splitting from the first light beam a second light beam (b4) which travels a delay optical path (DOP1) with a path length not less than the coherence length of the first light beam. The delay optical path returns to said first optical path at a deflection angle from said optical delay element. The illumination optical system may also include a plurality (i.e., second, third, etc.) optical delay elements or splitting delay stages (e.g., 213-215) having different path lengths.
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