摘要 |
An apparatus and method for mitigating a cold edge effect within a lithography mirror is presented. The apparatus includes a heated annular zone formed on a substrate and a heated optical aperture zone formed on the heated annular zone, where each zone includes a resistive layer, and where the resistive layer of at least one zone is produced such that electrical conductivity varies by increasing from the center of the resistive layer to the periphery of the resistive layer. A wiring layer in each zone includes an insulating sublayer and contacts for coupling to a power supply. A time-constant heat load on the lithography mirror is maintained by placing additional electrical heat loads on the mirror according to the actinic heat load on the mirror. Maintaining the time-constant heat load can reduce or eliminate variation in image distortion that occurs as a result of changes in the actinic heat load.
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