Wafer cleaning issues at the wet process
Model of the failure:
The chemistry evaporates too fast, therefore, particles remain on the
Short term solution:
Reduce the evaporation rate of the chemistry (water at rinsing)
- Increase air pressure above the wafer
- Reduce the temperature of the chemistry
- Adjust the flow of the chemistry and the rotation rate of the wafer to keep the chemistry on the wafer during the process. Keep in mind that the flow increases the amount of chemistry, while wafer rotation removes the chemistry from the wafer
Long term solution
Use a shower (multiple nozzles system) instead of a single movable nozzle. The flow should be adjustable above different areas of the wafer.
Shower:
Multy-nozzles system:
Adjust recipe for no "empty" areas on the wafer during the process
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