material request - Stycast W 19 epoxy

Mahnaz Mansourpour mahnaz at stanford.edu
Wed Sep 3 10:38:55 PDT 2008


Hello Peter,

I need a process flow with indication of equipment use please that would 
be very helpful to me.

mahnaz
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.)
>
> Mary
>
> 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.
>>
>> Thanks,
>> -Peter Chen
>
>



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