Thierry,

The RCA clean has many variants.  The RCA1 is a mixture of ammonium
hydroxide, hydrogen peroxide and water while the RCA2 is a mixture of
hydrochloric acid, hydrogen peroxide and water.  The variations occur in
bath mixing ratios, time and temperature.  I find the following works well

       RCA1             NH4OH:H2O2:H2O  1:1:5           75?C            15
min
       RCA2             HCl: H2O2:H2O           1:1:6           75?C
15 min

Regarding the etching of silicon in the RCA you might look at the ammonium
hydroxide to hydrogen peroxide ratio in the RCA1.  Ammonium hydroxide pits
silicon and in larger concentrations roughens silicon surfaces very fast.

Take a look at Handbook of Semiconductor Wafer Cleaning Technology by Werner
Kern, the book discusses the RCA clean (SC) in great detail along with other
cleaning procedures and issues.

Hope this helps,

Loren.



 -----Original Message-----
From:   thierry.bouchet [mailto:[email protected]]
Sent:   Tuesday, March 25, 2003 10:18 AM
To:     [email protected]
Subject:        [mems-talk] etching silicon with RCA

I have a problem with this procedure RCA:
HNO3
Rinse H2O
NH4OH + H2O + H2O2

the silicon is etched and i see some white large area ?

Why ?


_______________________________________________
[email protected] mailing list: to unsubscribe or change your list
options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk
Hosted by the MEMS Exchange, providers of MEMS processing services.
Visit us at http://www.memsnet.org/