Precise delineation characteristics for 1/spl times/X-ray mask using advanced electron beam mask writer EB-X3

Abstract

A variable-shaped electron beam (e-beam) mask writer, EB-X3 was developed for 100 nm node 1/spl times/X-ray mask fabrication. It features a stable electron column of 100 kV and the address unit of 1 nm. This paper describes delineation characteristics of the EB-X3 on X-ray membrane mask. We have evaluated image placement (IP) accuracy and e-beam proximity effects on the X-ray membrane delineated with the EB-X3. In order to achieve highly precise IP and CD accuracy, we evaluated beam drift, temperature control, mask blanks support method, resist process, and proximity effect. Precise temperature control and a three-point support pallet are keys for excellent IP. Good CD control less than 10 nm was obtained with low proximity effects with ZEP resist and normal-hexyl acetate developer. The EB-X3 was used for X-ray mask fabrication in conjunction with an X-ray stepper in exposure experiments.