Correlation study of actual temperature profile and in-line metrology measurements for within-wafer uniformity improvement and wafer edge yield enhancement

With advances in new technology it is getting more important to monitor all aspects of the influencing parameters in critical etch steps and utilize them as tuning knobs for within-wafer uniformity improvement and wafer edge yield enhancement. With this in mind, a study to dive into "measuring what matters" was designed to acquire electrostatic chuck (ESC) temperature measurements in actual process conditions using a KLA-TencorSensArray EtchTemp-SE (ETSE) wafer. The ESC temperature profile was measured on a 300mm wafer under plasma-on conditions to reproduce actual temperature conditions of wafers in the production process. Temperature maps were compared with a control reference (ESC temperature in static plasma-off status), and using this information, chamber to chamber matching was also investigated. Furthermore, a correlation study between ESC temperature and inline optical metrology measurements offers clear direction for process tuning through set-temperature modulations.