Electrical linewidth measurements of etched, N+-doped polysilicon submicron lines were carried out to study the effects of dose and gap on exposure latitude in proximity X-ray lithography. Isolated lines and equal line/space pairs having linewidths from 0.15 micrometers to 0.35 micrometers on the X-ray mask were printed in APEX-M resist at gaps ranging from 26 micrometers to 34 micrometers using a Karl Suss stepper. Lithography was carried out at the IBM Advanced Lithography Facility using the Helios 1 synchrotron. Low voltage scanning electron microscopy (SEM) measurements in top-down mode using the linear regression algorithm are compared to electrical linewidth measurements. Reactive-Ion Etch bias is determined by comparing top-down SEM of resist after exposure, on both 50 and 330-nm-thick polysilicon, to top-down SEM after etching. Both resist and etched line profiles are examined in cross section using SEM. The etch bias and the change in line profiles were found to account for most of the offset between the SEM and the electrical linewidth measurements. The results of SEM-measured averaged across the field, were also compared to two-dimensional aerial images (determined using average SEM-measured mask linewidths) and resist dissolution simulations to examine simulation accuracy.

Date Published: 19 May 1995
PDF: 12 pages
Proc. SPIE 2437, Electron-Beam, X-Ray, EUV, and Ion-Beam Submicrometer Lithographies for Manufacturing V, (19 May 1995); doi: 10.1117/12.209161

Published in SPIE Proceedings Vol. 2437:
Electron-Beam, X-Ray, EUV, and Ion-Beam Submicrometer Lithographies for Manufacturing V
John M. Warlaumont, Editor(s)