PATTERN DENSITY AND TRENCH WIDTH EFFECTS IN STI CMP: THEIR IMPACTS ON ELECTRICAL PERFORMANCE

摘要

Shallow trench isolation (STI) is becoming commonly used as an isolation scheme in integrated circuits. CMP has a significant impact on the performance of the STI module. Pattern density and feature size impact the post polish thickness within the die. This is important as excessively thick oxide can cause shorts, and recessed oxide can reduce the integrity of the isolation. Typically one monitors the thickness in a scribe line structure. In this paper the authors examine how we can predict the thickness at various locations within the die based on the scribe line monitor. We examine the impact of polish conditions and integration schemes on the final trench oxide thickness and device functionality. These effects are examined as a function of different slurries, slurry dilution, and for the dual nitride scheme.