Implementation of an in-situ particle monitoring methodology in a production environment

Abstract

The time and logistics associated with particle testing on product have driven manufacturing to find fast and effective monitoring techniques that can deliver high manufacturing efficiency at a lower cost. In-situ particle monitoring is an accurate and cost effective method of contamination control in a production environment. In-situ particle monitors use laser particle counters to sample particles exiting the chamber, the data is displayed in real-time enabling the user to respond immediately to any out of control conditions. Implementation of in-situ particle monitoring on a chemical downstream etch system in a production environment is described. The chamber clean cycles on this etch system are driven by polymer flaking from chamber parts, which makes real time particulate monitoring necessary. In-situ plasma clean process is characterized using in-situ particle monitors to reduce particulate flaking from chamber parts. All process steps during the etch step are also analyzed using in-situ monitors to identify and eliminate sources of particulate contamination. Implementation of in-situ monitoring resulted in a 92% reduction in test wafer costs, and also provided a model for predicting particulate perturbations in the etch system. Improvements in cleaning techniques resulted in a two fold improvement in the mean time between cleans.