Fwd: Photodefinable Polyimide

Arvind Kamath akamath at kovio.com
Fri Feb 1 18:43:39 PST 2008

Thanks Mary,

         This should suffice- we will use the headway- I think we can manage with the beaker dunking as a first choice. We will not start without full confirmation- Arvind
From: Mary Tang [mtang at stanford.edu]
Sent: Friday, February 01, 2008 6:38 PM
To: Paul Rissman
Cc: specmat at snf.stanford.edu; Arvind Kamath
Subject: Re: Fwd: Photodefinable Polyimide

Hi Arvind --

Polyimide may be used in the lab, but there are some process limitations....

First, I believe manual spin must be done on the headway only.  It is
much more difficult to cleanup polyimide in the laurell, so it is not
allowed there.

Second, I take it you mean 120 C bake on a hotplate?  This is what is
recommended and what people who use polyimide typically do -- we do not
have an oven at 120 C (it's at 110 C) and I believe hot plate is
considered better for this process.

Third, as for develop -- we should check with our maintenance guys.  I
take it that ordinary LDD26W (dilute TMAH) is sufficient, though don't
know if it is 0.26N as recommended in your process guide.  Also, the
develop dispense program is unlike what we have in our standard process
programs on the develop tracks, so we'd have to set up another program
(I'm not sure we have any program slots left).  Finally, polyimide is
not compatible with acetone, which is what is typically used to clean
the develop tracks (polyimide lumps up and clogs drains).  We should
check with the maintenance to see if and how polyimide develop can be
accomodated on the svgdev track.  If your photopatterning is not too
demanding, I would suggest trying first to develop by dunking in a
beaker.  First, it's easier to manage the waste/cleanup.  Second, for
thick films like this, develop quality is much better (develop rate
isn't diffusion limited, adhesion of small structures is better.)

Will you be curing after develop?  We have a Blue M oven for this
purpose.  Mahnaz trains on this.

Finally, please register your chemical with Mahnaz.

In summary, spin coating can be done on headway.  Spin cure can be done
on a hot plate.  Postcure can be done in the Blue M.  The track develop
is problemmatic and would require some effort and coordination to do.
Unless there is a compelling reason, I'd suggest trying dunk develop first.

Mahnaz, what do you think?


Paul Rissman wrote:
> Sorry for those of you who got this twice.
>> X-Sieve: CMU Sieve 2.3
>> Delivered-To: rissman at stanford.edu
>> From: Arvind Kamath <akamath at kovio.com>
>> To: Paul Rissman <rissman at stanford.edu>, "mahnaz at snf.stanford.edu"
>>          <mahnaz at snf.stanford.edu>, Ed Myers <edmyers at stanford.edu>
>> CC: Criswell Choi <cchoi at kovio.com>, Rosie Cordova <rcordova at kovio.com>
>> Date: Fri, 1 Feb 2008 16:05:04 -0800
>> Subject: Photodefinable Polyimide
>> Thread-Topic: Photodefinable Polyimide
>> Thread-Index: AchlL0MMPmirB8B4TsSgQ+YUsgQylw==
>> Accept-Language: en-US
>> X-MS-Has-Attach: yes
>> X-MS-TNEF-Correlator:
>> acceptlanguage: en-US
>> Paul, Mahnaz, Ed,
>>             Kovio would like to spin and KS expose a photodefinable
>> polyimide at SNF
>> Manufacturer: HD Microsystems
>> HD-8820 Photodefineable polyimide
>> We will need to manually spin, develop on track, oven bake at 120C.
>> For spin, we would need to bring in a bottle of the material and
>> store it at SNF if possible.
>>             Can you please let approve this (data attached)?  Of
>> course, we would just love to start using this bright and early
>> Monday morning 2/4/08 J
>>                                     Best regards,
>>                                                 Arvind Kamath

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