[labnetwork] PCB in e-beam evaporator?

[Michael Helmbrecht]

Hi Russ,

For a short-term summer project, you should be able to get by with regular
ENIG or ENEPIG, making your you specify soft gold. The surfaces should be
clean (O2 descum works great) and the boards should always be stored in a
very dry place for extended periods (1-2 weeks) so they don't swell when
heating. Make sure the nickel you are getting is the full 3-6 um thick per
typical plating standards.

The next level is to spec ENEPIG and ~1um soft gold electroplating on the
boards. Go with IPC-4556 metalization standards when you talk to the board
house, but make sure to add the electroplated soft gold!

Best,
Michael





------------------------------------------------------------------------------------------
Michael Helmbrecht, Ph.D.
Executive Director
Berkeley Marvell Nanofabrication Laboratory
520 Sutardja Dai Hall
Berkeley, CA 94720
(510) 809-8620
https://nanolab.berkeley.edu/
------------------------------------------------------------------------------------------

On Thu, Jul 2, 2026 at 5:06 AM Russ Renzas <rrenzas at unr.edu> wrote:

> For a summer lab class we're trying to have students make a chip and
> wirebond it to a PCB. We're having trouble wirebonding to the immersion
> gold pads though.
>
> Is it okay to put pcbs in our ebeam evaporator to evaporate Au?
>
> We tried a small piece in a Au SEM prep sputter coater and that worked but
> it's too small for the class PCBs.
>
> Thanks, also appreciate any tips on how to spec pcb metalization for
> wirebonding compatibility. We have both Al ultrasonic wedge and Au ball
> bond capabilities.
>
> Russ Renzas
> University of Nevada, Reno
> _______________________________________________
> labnetwork mailing list
> labnetwork at mtl.mit.edu
> https://mtl.mit.edu/mailman/listinfo.cgi/labnetwork
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mtl.mit.edu/pipermail/labnetwork/attachments/20260702/216fcfae/attachment.html>