EUV 노광 후 EUV 마스크 위의 Fe, Pb, 와 Sn 오염 입자 제거 거동

Abstract

Fe, Pb, and Sn particles released from the EUV scanner can contaminate the EUV mask causing serious yield and throughput problems. These contaminants can get worsen during EUV exposure and become difficult to remove, leading to damaging the EUV mask in the process. To effectively remove contaminants without causing any damage to the substrate, it is necessary to understand the behavior of the contaminants when they are removed. By simulating the EUV exposure heating from rapid thermal annealing, this study aimed to investigate the way Fe, Pb, and Sn particles are removed from a EUV mask surface after the EUV exposure. The quantitative measurement of the forces involved in the removal of the thermally aged Fe, Pb, and Sn particles from the surfaces of EUV substrates was carried out using an atomic force microscope (AFM). With the thermal aging time, the contact area of the deformed particle increases which requires a high removal force. After particle removal, the footprint of the contaminants was investigated to understand the surface quality of where the particles sat under the various exposure conditions. Using thermally deformed Fe, Pb, and Sn particles on a variety of EUV mask substrates, this study helps to investigate both the adhesion mechanism and the removal behavior of these particles.