In fact, if anything, the HF bearing clean would be detrimental to a
hydrophilic bond process, since that clean would remove the hydrophilic
oxide surface (to which the -OH species are attached after the RCA1
clean, which will, in turn, promote the hydrophilic bond via hydrogen
bonding).

Best Regards,
Chad Brubaker

-----Original Message-----
From:  Sumant Sood
Subject: RE: [mems-talk] how to process hydrophilic bonding?

Hi Nielei,
If your Si wafers have no particle problems (assuming they are prime
grade),
hydrophilic bonding should not be a problem. Do a RCA, SC1 Clean (5:1:1,
H2O, NH4OH, H2O2, preferably with ultrasonic or megasonics) for 15 to 20
minutes, followed by a DI rinse to activate the wafer surface.

I don't see any reason why you are you using the HNA etch
(65%HNO3:48%HF:H2O=5:100:0.001) as you mentioned prior to bonding. You
do not need this.