text stringlengths 1 2.97k |
|---|
I was wondering if anyone could send me a copy of the operation and |
maintenance manual ? |
Thanks in advance. |
Yours sincerely, |
SDI Fabsurplus Italia SRL |
Stephen Howe |
Company Owner |
email: info at fabsurplus.com |
Mobile (Italy) : +39 335-710-7756 |
Mobile (USA) : +1 830-388-1071 |
WWW.FABSURPLUS.COM |
Your Marketplace for Used Semiconductor Equipment |
-------------- next part -------------- |
An HTML attachment was scrubbed... |
URL: <https://mtl.mit.edu/pipermail/labnetwork/attachments/20230508/81deb911/attachment.html> |
From deolivei at ualberta.ca Tue May 9 16:13:24 2023 |
From: deolivei at ualberta.ca (Gustavo de Oliveira Luiz) |
Date: Tue, 9 May 2023 14:13:24 -0600 |
Subject: [labnetwork] Strange "sample memory" with LOR 5B |
In-Reply-To: <CALPuYFz9Y4TnP6WupwyCkR4Xgb7Rijczhibd7y_MVJnChTa4rw@mail.gmail.com> |
References: <CALPuYFzLg-QX5tPGX7qShke=8o75W=xVb_NB0tUYquFskr4FRg@mail.gmail.com> |
<BY5PR09MB544242B473B5C35D39DA3CE3BB849@BY5PR09MB5442.namprd09.prod.outlook.com> |
<MN2PR07MB6526DCA749B93665FC11C500CB849@MN2PR07MB6526.namprd07.prod.outlook.com> |
<CALPuYFz9Y4TnP6WupwyCkR4Xgb7Rijczhibd7y_MVJnChTa4rw@mail.gmail.com> |
Message-ID: <CALPuYFzTc122_7dp18gBbMW2eQYgCHAGk4W+VyCRdA7chGxemA@mail.gmail.com> |
Hello everyone, |
I just wanted to bring an update on this issue of ghosts when reworking |
wafers with LOR 5B, as well as give everyone a summary of the information |
the community provided since some of the replies seem to have been |
addressed to me only. |
*TL;DR: To get rid of the ghosts, O2 RIE for 5 min works but a barrel |
plasma asher for 20 min does not.* |
First the summary and some comments: |
- Some people suggested that developers may indeed etch the substrate |
and cause defects. While this may be true, and I saw that myself, this is |
not such an extensive problem and we don't see this as a problem when |
working on multi-layer projects. |
- Travis Massey brought up the issue of developer residue being trapped |
and not properly rinsed from the undercut region on lift-off masks. Again, |
I don't believe this is the problem, but I do think that this is worth |
paying attention to when developing this kind of recipe. We should think |
about longer rinsing steps to make sure that the developer is completely |
washed away from these harder to reach areas. |
- Dave Hollingshead suggested that local heating from the laser in |
DWL could cause surface modifications. This may be the case, but as my |
update below will show, at least in my case the issue is not irreversible. |
On the other hand, the fact that I also have this issue when using a |
contact aligner tells me that the issue may not be local heating, but it |
may still be some other surface modification due to interaction with light. |
And this must be something related to LOR 5B, since we don't observe this |
on our standard AZ1512 process. |
- A few people suggested that something in the lithography process may |
be changing the reflectivity of the substrate+resist layers. Everything |
points in this direction, however I was not able to determine what is |
causing this. Suggested solutions were O2 plasma (see my update below) and |
deposition of a 20 nm BARC layer before reworking samples. |
- Finally I'd like to address the effect that a few have reported |
regarding the hydrophobicity of the wafer after stripping resist, to which |
there was even a TikTok post about (neat!). We see that behavior after |
stripping the resist from a sample and rinsing it with water. Our |
understanding of this effect is that the exposure and development of the |
photoresist removes HMDS from the substrate, rendering the exposed areas |
hydrophilic while the remaining areas are still hydrophobic as HMDS is |
still there. At least in our case, a 15 min piranha (3:1) cleaning |
procedure is enough to get rid of the remaining HMDS and the whole sample |
becomes hydrophilic again. This is definitely not the cause of the ghosts |
we are observing and, even if HMDS was not completely removed, we apply |
HMDS again as part of the rework and this should make the surface uniform |
again. |
I hope I have covered all, or at least most of, the comments I got back. |
Now my update: |
- A 5 min O2 RIE step removed whatever it is from the surface of my |
wafers. My procedure was: strip LOR 5B/AZ 1512 with Remover PG (always new, |
so no water or other contamination), piranha clean for 15 min and O2 RIE |
for 5 min (P = 100 mT, RF = 200 W). |
- Since our RIE only supports one sample at a time, I tried doing a |
batch O2 ashing on a barrel plasma system. To our surprise, it did NOT |
work. After 20 min at 250?C, 600 W of RF power and 1.4 Torr, the ghosts |
were still there. |
I am sorry for the long message, but I thought that it would be useful to |
have a summary of the responses here for anyone looking for information |
about this. |
Cheers, |
-- |
Gustavo de Oliveira Luiz, PhD |
Applications/Research Specialist |
nanoFAB, University of Alberta |
+1 (780) 619-1463 |
On Fri, Mar 24, 2023 at 3:57?PM Gustavo de Oliveira Luiz < |
deolivei at ualberta.ca> wrote: |
> Hi everyone, |
> |
> First of all, thank you for the comments so far. If anyone else has more |
> information or suggestions about this, please keep them coming. I just |
> wanted to clarify some things and add a bit more detail on this issue. |
> |
> Travis Massey mentioned one thing that caught my attention, which was the |
> etching at the rims of the mask patterns, where developer may have been |
> trapped at after the undercut step with MF-319. Indeed, I observed this |
> kind of thing on a Si (no oxide) wafer where I measured up to a few 100 nm |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.