Book excerpt: This volume contains the proceedings of 13th International Symposium on Ultra Clean Processing of Semiconductor Surfaces (UCPSS 2016, Knokke, Belgium, September 12-14, 2016) (www.ucpss.org) and includes studies on cleaning such as particle removal using acoustic enhancement, removal of metallic contamination, pattern collapse of fine flexible and fragile features, wetting and drying issues, control and measuring of contamination . FEOL and BEOL topics cover: chemistry of semiconductor surfaces, cleaning related to new gate stacks, cleaning at the interconnect level, selective wet etching, resist strip and polymer removal, cleaning and contamination control for various new materials and cleaning after Chemical-Mechanical-Polishing (CMP)