material request - Stycast W 19 epoxy
mahnaz at stanford.edu
Wed Sep 3 10:38:55 PDT 2008
I need a process flow with indication of equipment use please that would
be very helpful to me.
Mary Tang wrote:
> Hi Peter --
> So, if I understand correctly, you'd like to glue your chips to a
> silicon wafer with chip pockets and process through litho and
> lift-off? A few questions:
> 1. Mixing and applying your epoxy. These are all liquids, correct?
> Do they require weighing or are they pre-measured? We don't really
> have the appropriate balance inside the cleanroom for this. However,
> we do have accurate balances outside the cleanroom (in the
> wafersaw/CMP room.) Would you be applying the epoxy from a syringe?
> Since the stuff appears to have a long working time, I'd suggest
> mixing outside the cleanroom and bringing the syringe (appropriately
> labeled and enclosed in something like a wafer box) into the cleanroom
> (through the service aisle) and applying it in a solvent bench. You
> could also mix inside the lab in a solvent bench, but I have not yet
> ordered a replacement balance as yet (though you are welcome to nag me
> about this). If you will be curing on a hot plate for several hours,
> please be careful to use foil (and not occupy all the hot plates at
> once.) The concern is that the epoxy will be very difficult to remove
> if it gets on cassettes, bench tops, or hot plates, so precautions
> should be taken to make sure none gets on these. If you want to store
> the unmixed chemicals in the lab, please get the appropriate labels
> from Mahnaz or me. The chemicals should be stored in the personal
> Flammables area. Any solid waste should be bagged and placed in one
> of the Flammables solid waste containers in the Litho area.
> 2. Standard litho flow should be OK for contact alignment.
> Hopefully, your desired resolution isn't better than a couple of
> microns. If this is for ASML, please check first with Mahnaz, Ed, and
> the ASML engineers.
> 3. PR lift-off in metalica should be OK.
> 4. Polyimide lift-off for standard polyimides is not a process we're
> familiar with. Fully cured polyimide is allowed in the gryphon, but
> is typically then very hard to remove by wet cleans. Polyimide that
> is not fully cured is not allowed in the gryphon because off gassing
> of volatile organics could contaminate the system. Polyimide, if I
> remember correctly, is also not typically allowed on the laurell, but
> only on the headway because it does not dissolve in acetone. If you
> really need polyimide in the gryphon, please provide more details (and
> probably another SpecMat request.)
> Peter Chen wrote:
>> Hi specmat,
>> Here is my request:
>> Material - Stycast W 19 epoxy, Catalyst 11, Catalyst 9, from Emerson
>> and Cuming
>> Where -
>> (1) a litho bench (for the exhaust)
>> (2) standard litho flow (after epoxy cure)
>> (3) PR lift-off in Metallica
>> (4) alternatively, polyimide flow at laurell then lift-off in Gryphon
>> Process -
>> (1) Insertion chiplets into backside of pocketed wafer. Mix, apply,
>> and cure epoxy at a wetbench (for exhaust). Epoxy only used on
>> backside of wafer.
>> (2) Downstream to standard litho equipment for other (non-epoxy)
>> litho steps on frontside
>> (3) PR lift-off process in Metallica
>> (4) polyimide lift-off in Gryphon if that can be approved.
>> Notes -
>> (1) I don't need a litho bench per se, I would just like an approved
>> place that has enough exhaust and 120C hotplate for curing
>> (2) Epoxy will be applied by syringe or pipette to chiplet insertion
>> sites only. Goal is to achieve a reconstituted wafer.
>> (3) Cured epoxy should easily handle 155C.
>> (4) The raw epoxy and catalyst can be stored at room temperature,
>> preferably in lab.
>> (5) After chiplet insertion into wafer backside, my process is to
>> have metal lift-off on frontside to complete the electrical contacts.
>> I need to cover some frontside topography, hence sputtering.
>> I have attached datasheet and MSDS. Please let me know if there are
>> other things I should bring to specmat.
>> -Peter Chen
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