Non-Standard Nitride Strip, contaminated
This process module covers the stripping of nitride at wbflexcorr-3and-4 or wbflexcorr-1and-2.
NITRIDE STRIP - WET, contaminated
- Use your own designated quartz beaker to prevent contaminating your wafers. If your wafers are already gold contaminated you may use the beakers or holders at wbflexcorr-3and-4 or wbflexcorr-1and-2 (most of them are gold contaminated). Once you use a contaminated beaker -- your wafers must be considered contaminated and are restricted as to what equipment they may use.
- Pour fresh Phosphoric Acid in your own designated quartz beaker and cover with your own designated lid to prevent evaporation.
- Heat solution to 155C.
- NOTE: Wafers should not have resist on them when going into nitride strip bath.
- Use your own designated Teflon cassette for this etch to prevent contamination.
- Dip wafers in your own designated beaker of DI water for 15 second.
- Immerse in 6:1 Buffered HF (in your own designated plastic or Teflon beaker) for 30 seconds. This is to remove any oxide layer that is on the top of the nitride.
- Overflow rinse (in your own designated beaker) for 5 minutes.
- Blow Dry.
- Immerse the wafers in DI water for 15 seconds (in your own designated beaker).
- Immerse the wafers in the hot Phosphoric (nitride strip) solution and replace the lid to prevent evaporation which effects the etch rates. The etch rate of nitride is about 32A/min. Oxide and silicon etch at about 0.8A/min. Over-etching by 20-40% is not unusual in order to clear the samples of nitride.
- Overflow Rinse with DI water for 5 minutes.
- Blow Dry.
- Inspect to be sure all the nitride has been removed (i.e. measure oxide under the nitride -- if it is less than or equal to what you had originally, the nitride is off.