Development of laser-assisted CD correction system in EUV masks

Laser-assisted CD correction system for EUV masks is developed in order to satisfy the enhanced uniformity requirement for EUV layers. Based on the very nature of chemical reactions, the reaction rate between the EUV mask absorber and wet etchant is controlled to develop EUV mask CD correction system. The CD correction facility is developed by selective temperature control through local laser illumination including considerations on laser wavelength, beam size, position precision under wet etching solution environment, resulting in ultra-fine control of wet etch rate to obtain a process. The process developed is expected to play an important role in EUV productivity as it is the only technology that can respond to specification requiring extreme CD quality control of EUV masks.