Retaining rings made of poly(phenylene sulfide) (PPS) and polyetheretherketone (PEEK) with two different slot designs were subjected to a 4 h wear test. During the chemical mechanical planarization (CMP) process, the PPS retaining ring induced a higher coefficient of friction (COF) by similar to 0.1 than the PEEK retaining rings. In addition, the PPS retaining ring exhibited a higher wear rate than the PEEK retaining rings by similar to 28%. Although the retaining ring slot design did not significantly affect the COF and wear rate, retaining rings with sharp slot edges resulted in higher pad surface abruptness. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3483752] All rights reserved.