Stencil reticle repair for electron beam projection lithography

Repair of stencil reticles for electron beam projection lithography system is one of the critical issues on reticle manufacturing.Focused ion beamdeposition is studied as the method for repairing the clear defects of stencil reticle. The film deposition of diamondlike carbon (DLC) across the stencil pattern, on the sidewall of the stencil, and on the pre-etched slot pattern is demonstrated. The deposited DLC films have good properties as the repair material.Deposited patterns across the stencil pattern are imaged on the resist with the Nikon 100 kV experimental projection column. When the thickness of the deposited DLC film is more than 0.5 μm and the contrast aperture size of the projection column is 1.5 mrad, the thickness of the deposited pattern does not affect the critical dimension of the resist pattern imaged the repaired patterns. The profiles, the pattern size, and the electron scatteringproperties of DLC films are stable for 100 kV electron beam continuous irradiation (2 C/cm2 dosage; corresponding to half-year dosage on electron beam stepper). Moreover, the repaired pattern is not damaged by the wet megasonic cleaning.