[labnetwork] [EXTERNAL] ideas to clean gold sputter target

[Dwayne Chrusch]

Two thoughts come to mind.

First, you could try and sand it with some wet automotive sand paper (2k grit). Use a piece of glass as a backing. Sand inside a baking pan. Once the debris is removed you can use the baking pan to pan for gold. Although a wok would work better for panning. Our just pour the slurry into a shallow container, and leave it on the wet deck for the water to evaporate. The high flow from the exhaust will speed up evaporation. 

Second, you could try 30% KOH at 80C. From our previous test, the only metal we have in our lab that hold up against KOH was Au. You probably have a waste bottle of KOH and/or a batch that is contaminated with photoresist. Set up the reflux bath and leave it in all day. Although, I'd keep an eye on it for the first 10 minutes [and check it every 30 after that]. 


Regards,

Dwayne D. Chrusch, BSc. (EE), MSc.
Operations Manager, Training & Safety Coordinator
Nanosystem Fabrication Lab (NSFL)
E3-471 Engineering
75A Chancellor's Circle
University of Manitoba
Winnipeg, Manitoba
Canada, R3T 5V6


> On May 10, 2025, at 1:06 PM, Tom Pennell <pennell at cnf.cornell.edu> wrote:
> 
> Caution! This message was sent from outside the University of Manitoba.
> 
> I would use the wet chemistry approach only if you have to. Flipping the target over will lead to non-uniform sputter target cooling and could further damage the target or tool. 
> 
> The best approach would be to order a new target and send this one to reclaim. You’ll get most of the cost of a new target back in reclaim value. A minimally costly mistake and an educational opportunity. Reclaim fees are minimal in comparison to a new gold target (hundreds vs thousands of dollars). The potential research impacts from using a contaminated target are far more costly! You’ll never be 100% certain that you’ve removed all contaminants. If necessary you could bill the responsible party for the reclaim expense and expedited shipment of a new target. 
> 
> The target appears to be 2” or 3” diameter by 1/4” thick - a common size. AJA International Inc and/or Kurt J Lesker may have one of these on hand to ship. Otherwise lead times are typically 3-4 weeks for precious metals. 
> 
> Best Regards,
> Tom Pennell
> Cornell Nanoscale Facility
> 
>> On May 10, 2025, at 12:32 PM, Robert Nidetz <nidetz at umich.edu> wrote:
>> 
>> 
>> Following up on the wet etching theme, piranha solution attacks a lot of metals, but not Au. 
>> 
>> Can you use EDS to determine the other elements?
>> 
>> Robert Nidetz, PhD (he/him/his)
>> University of Michigan
>> LNF User Liaison and Domain Expert
>> 1241 EECS Building
>> 1301 Beal Ave
>> Ann Arbor, MI 48109
>> nidetz at umich.edu
>> 734.496.8065
>> Book an appointment: https://calendly.com/nidetz
>> 
>> 
>> On Sat, May 10, 2025 at 8:18 AM Czwakiel, James <czwakj at rpi.edu> wrote:
>> Dr Rao
>> 
>> We have used scrubbing pads to clean off any oxidation or contamination 
>> You can also flip it over
>> Try the other side 
>> 
>> Jim
>> RPI
>> 
>> 
>> Get Outlook for iOS
>> From: labnetwork <labnetwork-bounces at mtl.mit.edu> on behalf of Fubo Rao <furao at ucsd.edu>
>> Sent: Friday, May 9, 2025 6:53:10 PM
>> To: labnetwork at mtl.mit.edu <labnetwork at mtl.mit.edu>
>> Subject: [EXTERNAL][labnetwork] ideas to clean gold sputter target
>>  
>> CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.
>> 
>> Dear Colleagues,
>> 
>> What would you recommend for cleaning this Au sputter target that has been partially coated/contaminated with other materials? There are probably a few material coatings on the target, before this was found out. Sputtering the materials off, or sand blasting will waste a lot of gold. Thanks in advance.
>> 
>> <image.png>
>> 
>> 
>> Thanks,
>> 
>> Fubo Rao, Ph.D.,
>> Nano3 Technical Director,
>> Qualcomm Institute/Atkinson Hall,
>> UC San Diego
>> 9500 Gilman Drive #0436
>> La Jolla, CA 92093-0436
>> Tel. (858)534-4518
>> Cell: (858)375-9190
>> E-mail: furao at ucsd.edu
>> https://nanofab.ucsd.edu/
>> About Nano3
>> 
>> _______________________________________________
>> labnetwork mailing list
>> labnetwork at mtl.mit.edu
>> https://mtl.mit.edu/mailman/listinfo.cgi/labnetwork
>> _______________________________________________
>> labnetwork mailing list
>> labnetwork at mtl.mit.edu
>> https://mtl.mit.edu/mailman/listinfo.cgi/labnetwork
> _______________________________________________
> labnetwork mailing list
> labnetwork at mtl.mit.edu
> https://mtl.mit.edu/mailman/listinfo.cgi/labnetwork