Virtual Metrology in RTP with WISR

The Applied Materials RTP systems are unique in providing high resolution process data particularly lamp power and temperature as a function of radial position and time. This work explores how these data can be exploited to predict on-wafer process results using an SPC analysis package named WISR. WISR is an advanced process control platform for collection, storage, visualization, and analysis of data from process tools. The product is collecting data at rates up to 100Hz. It has the ability of notification and interdiction if data goes outside of specification. One of its main features is the ability to create virtual sensors. These are parameters that are derived from physical sensors and provide a statistical representation of the process health. The focus of this paper is the ability of WISR to transform the time series chamber data from the pyrometers into thermal wafer images at any time window during the recipe execution. We describe the data analysis that was deployed, and show how temperature maps generated correlate with metrology data from RTP processes. This is a disruptive new method to significantly save monitor wafer cost, enhance yield and prevent wafer processing errors.