In this study the effects of front-side pad composition were examined for a chemical mechanical polishing process. The examination involved evaluation of film removal uniformity across the wafer surface and within each die, dishing effects, and selectivity between silicon nitride and CVD oxides. Trenches were fabricated in the substrate via dry etch, the resultant depth was 1.5 μm. The trench backfill was accomplished with a CVD low temperature oxide. Best results were obtained using a dense single layer polish pad, which exhibited imperceptible dishing and wafer polish uniformity on par with all other combinations.
Zelenak, James K.
"Chemical Mechanical Pad Characterization Using shallow Trench Isolation Structures,"
Journal of the Microelectronic Engineering Conference: Vol. 8
, Article 18.
Available at: http://scholarworks.rit.edu/ritamec/vol8/iss1/18