Important Notes:

1. Make sure wafers have never had GaAs or metal on them and have not been in any GaAs or metal contaminated equipment or contaminated beakers. Check MATERIALS to determine what equipment use and what materials are allowed.

PROCESS

1. Check etch rate of the etch you plan to use. Most people either use 6:1 Buffered HF or 20:1 Buffered HF.
2. Using the Teflon cassette designated for this bench, dip test wafer in DI water for 15 seconds.
3. Immerse in Buffered HF for calculated etch time. Note: It is sometimes useful to clear a patch of resist near the edge of the wafer to watch for it to go hydrophobic to determine the etch time required. This can be done using a QTip and Acetone for positive resist.
4. Dump Rinse.
5. Spin Dry
6. Inspect for undercutting and measure to be sure oxide is removed.
7. Process the rest of the wafers (steps 2 through 6).