23 March 2009 Quantitative measurement of voltage contrast in SEM images for in-line resistance inspection of wafers manufactured for SRAM
Author Affiliations +
Abstract
An in-line inspection method for partial-electrical measurement of defect resistance, which is quantitatively estimated from the voltage contrast formed in an SEM image of an incomplete-contact defect, was developed. This inspection method was applied to wafers manufactured for an SRAM device. That is, the gray scales of the defect images captured on an SRAM plug pattern were quantitatively analyzed. Accordingly, the gray scales of defective plugs formed for shared contact patterns were classified as two levels. The higher contrasts, which were calculated from the grayscales of the darker defects, were about 100%; the lower contrasts, which were calculated from the grayscales of the other defects, were from 38% to 60%. The resistances of these defects were estimated from a calibration curve obtained from the grayscales of the SEM images and the resistances of deliberately formed failures on standard wafers for voltage-contrast estimation. The estimated resistances of the lower-contrast defects (with an accuracy of about an order of magnitude) agree well with the resistances measured by nano-prober. It is concluded that this in-line inspection method for partial-electrical measurement is a useful technique for defect classification based on defect resistance and defect mode.
© (2009) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Miyako Matsui, Takahiro Odaka, Hiroshi Nagaishi, Koichi Sakurai, "Quantitative measurement of voltage contrast in SEM images for in-line resistance inspection of wafers manufactured for SRAM", Proc. SPIE 7272, Metrology, Inspection, and Process Control for Microlithography XXIII, 72721D (23 March 2009); doi: 10.1117/12.812949; https://doi.org/10.1117/12.812949
PROCEEDINGS
8 PAGES


SHARE
Back to Top