_{STANDARD PRE-LPCVD OR PRE-METAL CLEAN (non metal @ wbdiff)}

_{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.}
2. _{If wafers have been scribed or have resist on them they should get the resist strip process at the wbnonmetal before going into wbdiff.}

_PROCESS

• _{10 minutes in H2SO4:H2O2 (4:1) @ 90 C}
• _{Dump Rinse (std 6 cycles)}
• _{10 minutes in H2O:HCl:H2O2 (5:1:1) @ 70 C}
• _{Dump Rinse (std 6 cycles)}
• _{15 seconds in HF (50:1) @ room temp}
• _{Dump Rinse (std 6 cycles)}
• _{Spin Dry (Auto; Rinse 120 sec; Dry 280 sec; Resistivity >16 M ohm-cm)}

_{Note: Wafers must be loaded into furnaces within 1 hour after clean -- or re-clean them.}