First wafer effect through idle time
Material  Processes VIA etch
Supplier TEL Chamber Principle Dual Frequency
Topic Process Stability Chamber Hardware IEM
Reference G. Spitzlsperger, Renesas Technologies, et al.: 'In-situ Real-time Monitoring of a Via Etching Process', SEMATECH AEC/APC Symposium XV, Colorado Springs, USA, 2003.  
   
Problem Determine the maximum idle time to avoid the first wafer effect.
Effect The major reasons of the first wafer effect are temperature drift and chemical conditioning of the chamber wall.

These effects cause:
  • Drift of plasma parameters.
  • Changed process parameters and process results (CD).
  • Yield losses.

The dependence of the collision rate on the tool idle time indicates a maximum idle time of approx. 10 min.
Measure Check the chamber status (temperature and gas composition) by plasma parameters.
Benefit Yield improvement through controllable first wafer effect.