Polishing of silicon by the cupric ion process

This paper describes a newly developed chem-mech polishing process for silicon wafers. This polishing process, without using any abrasives, can produce a silicon surface free of work damage. A solution composed of cupric nitrate, ammonium fluoride, and nitric acid is used on a conventional polishing wheel. The rate of stock removal is controlled primarily by the composition of the solution and the polishing wheel temperature. Highly polished surfaces have been obtained with stock removal rates as high as 20 mils per hour. At higher removal rates, the process is difficult to control and surface quality suffers.