Etch Rate Predictor

It combines input from the HF monitor and operator input specifications to calculate and then provide in real-time a recommendation for the amount of HF or H2O to add to the bath. It adjusts and maintains the appropriate ratio of chemicals to achieve accurate etching of the wafers.

This real-time process feedback can result in the reduction of, or even elimination of, process monitor wafers, which translates into considerable savings in operating expenses. Real-time monitoring makes closed loop solutions possible.

  1. Features

    etch monitor
    1. Inputs from the HF Monitor:
      1. HF concentration in weight percent
      2. Temperature in degrees Celsius
    2. Inputs from the operator:
      1. Total bath volume
      2. Bath target HF to H2O mix ratio
      3. Bath target temperature
      4. Bath target temperature limits
      5. Etch rate adjust factor

  1. Feedback displayed from the Etch Rate Predictor:

    etch monitor
    1. Actual bath mix ratio
    2. Actual bath temperature
    3. Warning if the HF concentration is out of limit
    4. Warning if the HF temperature is out of limit
    5. Recommendation on how much HF or H2O to add (spike) if the mix ratio is out of limit
    6. Estimated SiO2 etch rate

  1. Facility Requirements

    1. Valid for HF concentration ranges of .1 to 5.0 weight percent
    2. Valid for HF bath temperatures from 14 to 34 degrees Celsius
    3. Accuracy of estimated SiO2 etch rate is +/- 2% with proper etch adjustment factor
    4. 110 AC
    5. Connection to the HF monitor with a 9 pin RS232 cable