Wet Bench Upgrades

[Mary Tang]

Dear Labmembers:

As you may be aware, SNF is in the process of upgrading the key the wet 
benches. We thought we’d take a moment to tell you more about these 
upgrades.

The driving force is to upgrade the dump rinsers. As many labmembers 
have previously noted (ie., patiently complained), the dump rinsers are 
of various vintages and rinse to varying degrees of effectiveness over 
varying lengths of time… But as you might suspect, wafer rinsing 
technology has advanced significantly in last 25 years. The new dump 
rinsers are gentle spray/overflow, which has been shown to result in 
fewer particles (because there’s less static generated) and minimize 
damage, especially to MEMS devices. In addition, these are also more 
water-efficient – largely because they are smaller as they are designed 
to hold one 6” cassette instead of two (don’t worry, extra replacement 
dump rinsers are being installed in high-use stations to handle peak 
demand.) And they have a built-in feature which allows monitoring of 
resistivity.

Because the new dump rinsers have a smaller footprint, new layout and 
decking is required. So, we have also taken this opportunity to lower 
the decking by at least 1 ½” this is to increase headspace to make it 
easier to handle cassettes (especially 6”) and pour chemicals. Many 
other changes (consistency in layout between benches, improved access 
for maintenance, etc.) are also being incorporated as well.

Funding for this upgrade has been provided by a rebate/grant from the 
Stanford Facilities & Operations group, as it is anticipated that the 
savings in DI water should pay for this upgrade within two years. The 
grant, however, stipulates that all upgrade work should be complete by 
the end of June in order to qualify, so that puts us on a time schedule. 
So far, wbmetal, wbnonmetal, and wbsilicide are now complete (if you 
haven’t done so already, check them out – they are beautiful!) Granted, 
things haven’t gone quite as smoothly as we’d like and there are a few 
issues that still need to be addressed – but we’d like to ask everyone 
to realize the complexity of this upgrade and the timeline under which 
it needs to be accomplished.

Two more things. first, a word about logistics… “wbdiff” is slated to be 
upgraded this week. “wbsilicide” will serve as the backup until wbdiff 
is functional again. wbsilicide will be decontaminated this afternoon 
and will be unavailable for use as a semiclean station or for 
decontamination until wbdiff is back to general use. In coming weeks, 
wbnitride (which because of the nitride pot will not have a lowered 
deck) and wbmiscres/headway2 (which will have a stainless deck installed 
for cleanliness/contamination) will be upgraded -- Check the email 
archives/Coral for updates and other specific info. When you use these 
upgraded stations, please do take good care of them (clean up after 
yourself, rinse away any chemical drops, etc.) and do note any problems 
that you encounter.

Second, Jim Haydon deserves ALL the credit for making this happen. While 
assembling wbgeneral2, he realized that the new dump rinsers could 
benefit the rest of the lab. He then consulted with process staff, did 
the research, and came up with the grant proposal to Facilities & 
Operations. He has also worked with lab- and staff- members to come up 
with improvements that could be incorporated with the basic upgrade. 
Thus, Jim’s project will not only have the environmental impact of 
saving water, but improve the safety and ergonomics for users and 
improve our ability to keep these stations clean and functional. 
(THANKS, JIM!!!)

Again, we ask you for your forebearance and thank you for your patience 
while these upgrades are being done.


Your SNF Staff

-- 
Mary X. Tang, Ph.D.
Stanford Nanofabrication Facility
CIS Room 136, Mail Code 4070
Stanford, CA  94305
(650)723-9980
mtang at stanford.edu
http://snf.stanford.edu