Material removal and particulate generation during abrasion of copper films using a fixed abrasive pad

Minimization of particulates levels during the chemical-mechanical planarization (CMP) process as well as in the waste streams is possible through the use of a fixed abrasive pad (FAP). The abrasion of electrodeposited copper films using an alumina-based FAP was studied in hydrogen peroxide and hydroxylamine-based chemistries. The removal rate of copper in hydrogen peroxide solutions was much lower than that in hydroxylamine-based solutions in the pH range of 3 to 9. The addition of citrate to peroxide solution enhances the removal rate of copper to a level that is comparable to removal rates in hydroxylamine-based solutions. Abrasion in a hydrogen peroxide solution resulted in the formation of copper and aluminum-based particulates in the solution. The addition of citrate to peroxide solutions reduced the generation of copper-based particulates that were generated in solution. In hydroxylamine-based solutions, particulate generation was minimal.