Thickness monitor

SIGMA SQM160 thickness monitor operation

  • Connect sensor to feed-through bolt in chamber wall with a microdot in-vacuum cable).
  • Connect the oscillator input (labelled 'feedthrough') with the small BNC cable to the feed-through bolt connector.
  • Connect the oscillator output (labelled 'instrument') to Channel 1 plug in the rear panel of the monitor.
  • Turn ON the monitor. A permanent green light shines in the 'crystal status #1' (if the led blinks, it means that there is a poor connection: check the cables and that the sensor holder is tight on the support).
  • Breath gently on the sensor: the thickness should go up and down as water vapour deposits on it and then evaporates. That is the test to check that it works (do it before you close the chamber!).
  • Press 'Program' to check the coating parameters (see p2-3 of the booklet): most important is Al density 2.73, Z-factor 1.08, Tooling 100 (or what you determined). Press 'Next' to scroll down the list.
  • Press 'Zero' to reset the counter when you start aluminizing in order to see easily have the elapsed time of the process.



Max Boccas, last revision on February 1st, 2001