PATTERN GEOMETRY-EFFECTS IN THE CHEMICAL-MECHANICAL POLISHING OF INLAID COPPER STRUCTURES

We describe an investigation into the pattern dependence of dishing an d erosion during the chemical-mechanical polishing of copper used for delineating inlaid metal patterns. Copper dishing is determined to be highly dependent on the width of the copper structure, but only minima lly dependent on the density of copper structures. Erosion of the SiO2 dielectric layer is strongly affected by the pattern density, but not affected by changes in the width of the copper lines. As a result, bo th line width and pattern density are important considerations in pred icting the final thickness of the copper lines.