Chemical Mechanical Polishing of Soft-Brittle Cadmium Zinc Telluride Wafers Using a Developed Environment-Friendly Solution

Abstract

A novel chemical mechanical polishing (CMP) solution was developed. The CMP solution developed consisted of mainly silica, hydrogen peroxide, and malic acid. CMP solution is environment-friendly, which is different from those used in conventional CMP, consisting of acids or organic solvents. Fixed abrasive waterproof paper of alumina with mesh size of 3000 was used as lapping tool, to avoid embedding of free abrasives on soft cadmium zinc telluride (CdZnTe or CZT) surfaces employed in traditional lapping processes. The diameter of silica was varied from several tens of nanometers to 100 nanometers. Surface roughness Ra, and PV achieved using fixed abrasive lapping and developed CMP solution are 0.6 nm and 6.3 nm, respectively. The polished CZT surface was cleaned by deionized water and dried using compressed air, to avoid damages induced by conventional physical wiping and ultrasonic cleaning on soft-brittle CZT wafers.