Polymer control in aluminum etch chambers to achieve >450 hours MTBC

Particle control is an important objective in Al etch systems. Unquestionably, polymer buildup must be kept under control. Defects, which result from chamber flaking, typically bridge metal lines together, resulting in lower yield. Excessive polymer buildup requires a chamber wetclean, consuming manpower and equipment uptime. Currently, most metal etch process chambers in the world require a wet clean at 90 - 150 hours. This article presents measures to control polymer buildup, and a qualification procedure to ensure the cleanliness of the chamber prior to running product. It will also show how Cypress Semiconductor has improved its metal etch mean time between cleans to 350 - 450 RF hours while improving yield.