The Particle Measuring Systems VacuLaz Vacuum Particle Counter measures contaminants in exhaust lines of process chambers and loadlocks. The VacuLaz system consists of a viewing module, a sensor and an electronics interface module. Depending on the application, aluminum is used in the construction of the viewing module with sapphire coated windows. The viewing module is installed in the roughing line with no loss of conductance. To reduce condensation on the windows, the optical module is heated. Particulate sampling from the sensor is transmitted to the interface module where the signal is converted and sent to a personal computer for displaying the data. PMS' VACU-View software package allows an operator to view in real-time raw particle counts in a time series plot. Particle counts from a single wafer, batches of wafers or individual processing steps can be plotted for analysis. An operator can also assign tool tags to specific events within the process and plot this data for establishing trending information. Since every process tool is a unique piece of equipment, it is important to develop and record a signature pattern during operations to understand its characteristics. The VACU-VIEW software can also retrieve data for generating event-based plots. Sizing sensitivity for the VacuLaz sensor starts at 0.2µm and offers with up to four channels with the first threshold being operator adjustable from 0.2 to 0.3 microns. The VacuLaz system is compatible with most known corrosive gases used in vacuum processing environments