The benefits of using Statistical Process Control for monitoring and/or controlling a process are well known. In Situ Host applies this technique to Residual Gas Analysis (RGA). Using a secondary integrated instrument with advanced software enables statistical tool control for those traits not well controlled by the native tool (i.e. leaks).

The example exhibits the use for monitoring leaks in a transfer chamber of a PVD tool. When a slitvalve is opened, the algorithm assigns the data to the correct data group. For every run (usually one wafer), the Average, Standard Deviation, and Maximum value are collected. A fourth linked spreadsheet allows the use of SPC to monitor these values.

Statistical Tool Control

The tool becomes the babysitter. Every sequence where a process chamber valve opens becomes an opportunity for inspection, and the tool is never removed from operation.