I want to thank John Shott at Stanford for the information on wafer cleans,
as this will form the basis for what I plan to implement here at NJIT for
efficient ionic decontamination. At the same time, I have to apologize for the
lack of a subject line in the last message, as I sent it off accidentally
before editing the header.
What I've decided on is to utilize one of our H2SO4 baths already in use as
a resist strip process for the stage one clean of organics. The H2SO4/H2O2 is
known for good carbon bond breaking in organic cleaning already, so this will
remain in place. Stage two will be an RCA-2, for metal ion desorbtion,
consisting of 5:1:1 of H2O:HCl:H2O2. This will allow for minimal change over
(low cost), and minimize problems with salt formation using RCA-1 and RCA-2
under the same hood. John also mentioned silicon pitting problems with the
use of NH4OH when H2O2 depletes, which is another problem to be avoided.
Although we don't currently have a method of monitoring clean effectiveness,
we may look at chemical analyses to be performed as a before/after check when
the baths are to be changed out. This would be a comparison of using stage one
alone (P-clean only), and stage one with stage two (organic with ionic clean),
as the new setup.
John
-- ---------------------------------------------------------------- John M. Koons *NJIT Microelectronics Research Center* Research Engineer e-mail: jmk4336@megahertz.njit.edu phone: (201) 596-8450 fax: (201) 642-4848 ----------------------------------------------------------------
This archive was generated by hypermail 2b29 : Tue Mar 09 2004 - 07:48:59 EST