Approval to bring 509 crystalbond stripper into SNF

Mary Tang mtang at
Tue Mar 15 12:24:13 PDT 2011

Hi Srikant --

Yes, CrystalBond 509 is approved for use at SNF, following standard 
procedures (grinding and mixing outside the lab, appropriate labeling 
and storage inside.)

This is stripping chemical is very interesting.  A couple of concerns 
though.  It's true that this is a lot safer from a flammability 
standpoint, but I'm not sure it is so from a health perspective.  The 
main ingredient has a TWA of 10 ppm whereas acetone is something like 
500 ppm (although I grant that it's skin versus inhalation and I'm not 
sure this is comparing apples to apples) -- also the LD50 is higher for 
acetone (oral, rats).

The other question is what "glycol ether" means.  We've phased out  
glycol methyl ethers because the US semiconductor industry has banned 
them for health reasons (linked to reproductive problems), though Europe 
and Japan have not followed.  Glycol ethyl ethers however, are OK, I 
believe -- or at least US semiconductor chemicals are now using these.

Although CrystalBond 509 is approved in other labs, it would be 
interesting to know if the remover is also approved.  Also, if it is 
possible to find out whether the glycol ethers used in the remover are 
the methyl or ethyl (or higher) variety.

I'd be willing to go with limited use for evaluation purposes (time 
limit, no sharing, review of health risks and handling, etc.) but would 
not be willing to go so far as to support approval without more 
information.  If you want to go with limited use, please talk with 
Mahnaz or me.  Otherwise, more information would be needed.



On 3/14/2011 3:36 PM, Srikant Vaithilingam wrote:
> Dear SpecMat Committee,
> I would like to request permission to bring the solvent '509-S 
> stripper' into the SNF cleanroom.
> This is a solvent that dissolves Crystalbond 509 which is used to 
> mount wafers temporarily onto a carrier wafer for use in such tools as 
> STS2.
> Crystalbond 509 is already approved for use inside SNF on the 
> recommendation of STS and following similar practices at the Univ. of 
> Michigan, Ann Arbor and Georgia Tech.
> '509-S Stripper'  is a non-hazardous, non-flammable solvent, and I 
> hope there can be a quick approval to bring this solvent into SNF.
> I have answered all the questions posed on the SNF website for SpecMat 
> approval below.
> Thank you,
> Sincerely,
> Srikant
> 1)Name: Srikant Vaithilingam
> Coral login: srikantv
> Phone: 650-723-0297
> Email: srikantv at <mailto:srikantv at>
> PI: Prof. Butrus T. Khuri-Yakub
> 2)Solvent Name: Crystalbond 509-S Stripper
> MSDS: attached to this email
> 3)Vendor:               SPI Supplies Division / Structure Probe, Inc.
> 569 East Gay Street
> P.O. Box 656
> West Chester, PA 19381-0656 USA
> *Phone:*  1-(800)-2424-SPI Toll-free from USA/Canada
> *FAX:*     1-(610)-436-5755
> *E-mail:* spi3spi at 
> <mailto:spi3spi at>
> *WWW:* <>
> Manufacturer:  Aremco Products, Inc.
> 707-B Executive Blvd.
> Valley Cottage, NY 10989
> 4)Reason for request:
> Using crystalbond to mount a wafer onto a carrier wafer is the 
> recommended operating procedure for use in STS2. Many other 
> laboratories use the same method including LNF (Univ. of Michigan, Ann 
> Arbor) and Georgia Tech.
>                 Using 509-S stripper to dissolve the crystalbond after 
> use is the recommended method from the manufacturer of Crystalbond. It 
> has many advantages over acetone including the following:
> "It features a very low evaporation rate, it rinses off easily with 
> water, it is non-flammable, non-reactive with metals, and it is also 
> biodegradable...But the most attractive part about the use of the 
> stripper, relative to acetone, is that one need not be exposed to 
> potentially harmful (acetone) vapors"
> 5)Process Flow:
> I will use the 509-S stripper only at WBsolvent to debond the carrier 
> wafer from the etched wafer.
> 6)Amount and form:
> I will bring in 1 gallon (liquid) of the stripper in a plastic bottle 
> similar in size and look to the current containers for acetone, 
> methanol etc.  It will be appropriately labeled with the chemical 
> name, my name etc.
> 7)Storage:
> I would like to store the solvent inside SNF. Storage group 'L'  or 
> 'G' would be fine.
> 8)Disposal:
> I will dispose of the chemical in the same carboy as the other 
> solvents at WBSolvent.

Mary X. Tang, Ph.D.
Stanford Nanofabrication Facility
Paul G. Allen Room 136, Mail Code 4070
Stanford, CA  94305
mtang at

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