EUV mirror with improved optical stability

An extreme ultraviolet (EUV) mirror system comprising:

• a projection optics box (POB) that comprises:
• a vacuum chamber;
• and
• a plurality of EUV mirrors disposed inside the vacuum chamber and arranged respective to a reticle stage and a wafer stage to project an image of a reflective EUV photolithography mask disposed on the reticle stage onto a wafer disposed on the wafer stage, each EUV mirror of the plurality of EUV mirrors including a mirror support and an EUV-reflective multilayer disposed on a front side of the mirror support;
• wherein the plurality of EUV mirrors includes at least one heated EUV mirror that further includes a resistive heater, the mirror support of each heated EUV mirror including a mirror substrate and a dielectric or ceramic layer disposed on the mirror substrate, the EUV-reflective multilayer being disposed on the dielectric or ceramic layer, and wherein the resistive heater of each heated EUV mirror is embedded in the dielectric or ceramic layer of the heated EUV mirror.

A method of manufacturing an integrated circuit, the method comprising:

• disposing a photoresist layer on a semiconductor wafer;
• exposing the photoresist layer on the semiconductor wafer to extreme ultraviolet (EUV) light using a projection optics box (POB) of an EUV lithography scanner;
• after the exposing, developing the photoresist layer to form openings in the photoresist layer;
• and
• after the developing, performing at least one wafer processing operation on the semiconductor wafer through the openings in the photoresist layer;
• wherein the POB comprises:
• a vacuum chamber;
• and
• a plurality of EUV mirrors disposed inside the vacuum chamber and arranged respective to a reticle stage and a wafer stage to project an image of a reflective EUV photolithography mask disposed on the reticle stage onto a wafer disposed on the wafer stage, each EUV mirror of the plurality of EUV mirrors including a mirror support and an EUV-reflective multilayer disposed on a front side of the mirror support;
• wherein the plurality of EUV mirrors includes at least one heated EUV mirror that further includes a resistive heater, the mirror support of each heated EUV mirror including a mirror substrate and a dielectric or ceramic layer disposed on the mirror substrate, the EUV-reflective multilayer being disposed on the dielectric or ceramic layer, and wherein the resistive heater of each heated EUV mirror is embedded in the dielectric or ceramic layer of the heated EUV mirror;
• wherein the exposing includes controlling a temperature of the at least one heated EUV mirror of the POB.