Modeling of reverse tone etchback shallow trench isolation chemical mechanical polishing

In this paper, we introduce a mathematical model for chemical mechanical po lishing (CMP) of reverse tone etchback shallow trench isolation (STI) struc tures. We present a detailed formulation of the model and describe CMP expe riments using a newly designed STI CMP characterization mask to validate th e model. A methodology for extracting the model parameters is also proposed . An improved modeling methodology that incorporates density averaging effe cts fits the experimental data more accurately. Finally, we use the model t o predict the effects of pre-CMP step height, pattern density, polish time, pad hardness, and slurry selectivity on dishing and nitride erosion. (C) 2 001 The Electrochemical Society. All rights reserved.