A heated vapor sublimation trap, which has heaters at the inlet to prevent clogging, removes contaminants from vacuum process systems before they reach the pump. The trap catches ammonium chloride byproducts generated in the semiconductor process LPCVD silicon nitride. The two-stage design traps effluent by-products in the first stage and particulates in the second.

HPS Products MKS Inc., 5330 Sterling Dr., Boulder, CO 80301, (800) 345-1967.