In Situ Lateral Force Technique for Dynamic Surface Roughness Measurements during Chemical Mechanical Polishing

摘要

We report on a technique for measuring dynamicsurface roughness changes during the chemical mechanicalpolishing (CMP) of metal and dielectric films. The technique isbased upon the measurement of lateral frictional forces duringthe CMP operation. These measurements were carried out inparticle-free slurries, which led to reduced noise in themeasurements. Under constant slurry and pad conditions, thefrictional forces were dependent on the surface roughness of thesilica and tungsten films. For silica, the lateral frictional forceswere approximately constant with polishing time, suggesting nosignificant change in surface roughness during polishing time.However, for tungsten, the force response changed drasticallywith time. The change in response was correlated with changes inthe surface morphology of tungsten during the experiment.