Specific Process Knowledge/Characterization/Stress measurement

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Stress measurements of a thin film can be done measuring the wafer bow before and after deposition of the film. If the film is deposited on both sides of the wafer you can measure the bow after deposition and again after removing the film from one of the sides.

The procedure is as follows:

When the deposition is on one side of the wafer

1. Measure the wafer bow on one of the profilometers (Dektak XTA_new or Dektak 8). Save the measurement. It is a good idea to measure across most of the wafer (at least along 70% of the wafer length) in two directions perpendicular to each other.
2. Deposite the thin film
3. Measure the wafer bow again:
   • On the same profilometer as used for the pre-measurement.
   • With the same recipe as used for the pre-mesurement.
   • On the same position/positions on the wafer as the pre-measurement .
4. Measure the thickness of the substrate
5. Measure the thickness of the thin film (ex. using the FilmTek or the Ellipsometer is possible).
6. Use the program for stress measurement in the profilometer software on the profilometer you used for the measurements. Use both the pre-stress measurement and the post-stress measurement.

When the deposition is on both sides of the wafer

1. Deposite the thin film
2. Pre-measurement: Measure the wafer bow on one of the profilometers (Dektak XTA_new or Dektak 8). Save the measurement. It is a good idea to measure across most of the wafer (at least along 70% of the wafer length) in two directions perpendicular to each other.
3. Remove the thin film from one side of the wafer. If it is a single side polished wafer, remove it on the non-polished side.
4. Measure the wafer bow again:
   • On the same profilometer as used for the pre-measurement.
   • With the same recipe as used for the pre-mesurement.
   • On the same position/positions on the wafer as the pre-measurement .
5. Measure the thickness of the substrate
6. Measure the thickness of the thin film (ex. using the FilmTek or the Ellipsometer is possible).
7. Use the program for stress measurement in the profilometer software on the profilometer you used for the measurements. Use both the pre-stress measurement and the post-stress measurement.