Temperature rise of extreme ultraviolet lithography mask substrate during dry etching process

Experiments and numerical calculations were performed to investigate the dr y etching heating of mask substrate. Changes of the glass substrate tempera ture were observed by color changes of a heat-sensitive label pasted on the substrate. A simulation model based on a lumped heat capacity system was p roposed to investigate the heat transfer mechanism at the contact interface between the mask and the stage or carrier. When thermal radiation dominate s the heat transfer mechanism between the mask and the stage. a temperature rise of about 100 degreesC was observed and predicted for an etching time of 60 s. The heating of mask substrate cooled by the stage indicated a temp erature rise less than 43 degreesC. The cause of mask substrate temperature rise was found to be insufficient adhesion between the mask and stage. Est imation of thermal response of a 150-mm square standard glass substrate wit h a thickness of 6.5 mm was attempted using the simulation model based on t he experimental results. The dry etching of the mask substrates was found t o be a practicable and safe thermal process if the etching time is within 6 0 s.