Characterization of prototype silicon pitch artifacts fabricated by scanning probe lithography and anisotropic wet etching

Abstract

Scanning probe lithography (SPL) and anisotropic tetra-methyl ammonium hydroxide (TMAH) etching (SPL+TMAH) were used to fabricate a series of one-dimensional prototype pitch structures on (110)-oriented silicon substrates. Overall lateral dimensions of the test structure are 20 mum x 80 mum. Line scales, consisting of 10-mum-long, 100-nm-tall, and 40-nm-wide lines, are observable by optical and scanning electron microscopy (SEM). Etched features were produced with pitches varying from 100 nm to 8 mum. Large-scale pattern placement errors of the SPL tool have been evaluated by analysis of optical image data obtained with a calibrated optical metrology instrument. Small-scale errors were analyzed in the range of 100 nm to 2 mum using SEM. Sources of placement error are discussed and possible methods for minimizing them are presented. The SPL+TMAH process in conjunction with a closed-loop scan control has the precision necessary for repeatable device prototyping in the nanoscale regime. (C) 2005 American Vacuum Society.