[Japan Soc. Appl. Phys Digest of Papers. Microprocesses and Nanotechnology 2001. 2001 International Microprocesses and Nanotechnology Conference - Shimane, Japan (31 Oct.-2 Nov. 2001)] Digest of Papers. Microprocesses and Nanotechnology 2001. 2001 International Microprocesses and Nanotechnology Conference (IEEE Cat. No.01EX468) - Design and performance of a normal-incidence optical critical dimension metrology system