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.

Thanks
Sumant
Belford Research Inc.


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

Dear all:
   Now I`m try to do some hydrophilic bonding.At first, Si wafers are
cleaned by standard RCA1.But even after treated by
HNO3+HF(65%HNO3:48%HF:H2O=5:100:0.001),Si wafers do not wettable.Is the
recipe right? Please help me!Thanks a lot.
                                                       Nielei