Stencil reticle repair for electron beam projection lithography

Abstract

Repair of stencil reticles for electron beam projection lithography system is one of the critical issues on reticle manufacturing. Focused ion beam deposition is studied as the method for repairing the clear defects of stencil reticle. The film deposition of diamondlike carbon ͑DLC͒ 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 m 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 scattering properties of DLC films are stable for 100 kV electron beam continuous irradiation ͑2 C/cm 2 dosage; corresponding to half-year dosage on electron beam stepper͒. Moreover, the repaired pattern is not damaged by the wet megasonic cleaning.

Nikon EB stepper: its system design and preliminary performance

“…The other infrastructures for EPL are developing steadily. [5][6][7][8] In particular, resist and data post-processing systems are shifting to a practical evaluation phase. 9) …”

Development Status of EPL Technology.

“…The proof-of-concept works for repair [ 17,18], cleaning [ 18,19] and inspection[l2]j191 of a silicon stencil reticle have already been completed. Developments of tools for mass production are expected.…”