Multi-beam mask writer MBM-4000 for high-NA EUV era

We have developed a multi-beam mask writer MBM-4000 for the technology node A14 where high-NA introduction is expected. MBM-4000 is designed with patterning resolution enhancement, which is achieved by the adoption of the 10 nm beam size and the refined optics, in mind. To maintain the writing time contrary to the small beam size, the beam current density is increased to 4.2 A/cm². A large beam current may impact on the patterning resolution and the writing accuracy, and thus we employ measures such as the Coulomb blur reduction system, the corrections for the resist thermal effect and the substrate deformation targeted at EUV for the high current density. The writing test of MBM-4000 confirmed improvements in the dose latitude and the local CDU. We analyzed errors in local CD to prove that line edge roughness of resist patterns was a dominant contributor to the errors, rather than the e-beam. The refinement to optics is added by upgrading the charge effect reduction (CER) system, which reduces beam position errors caused by the resist charging by 30%. Enhancement of CEC accuracy led MBM-4000 to achieve the global position accuracy of 1.0 nm(3σ).