Requesting permission to use alumina as substrate in tylanbpsg

Mary Tang mtang at
Mon May 2 14:54:22 PDT 2005

Hi Stephanie --

The main concerns about processing non-standard materials in our LPCVD 
furnace is the possibility of cross-contamination.  If you could 
possibly acquire elemental analysis on the alumina, this would be very 
helpful for allowing the SpecMat committee determine whether there is a 
likelihood of contamination.  We would also like a detailed process flow 
-- in particular, what kind of pre-deposition cleans and any 
post-deposition processing you may require.

What are the dimensions of your alumina?

Finally, would it be possible to use PECVD dielectrics instead of LP 
glass?  The reason I ask is that we have a PECVD system (STS) which can 
accomodate a broad range of substrate sizes, and is "gold-contaminated" 
and therefore can be used without an awful lot of in-depth consideration 
of trace contaminants.  The STS cannot do doped materials, but can be 
used to deposit oxides, nitrides, and oxynitrides of varying 
compositions and levels of stress.


Oberg, Stephanie wrote:

>Hi Mary -
>Thanks very much for your prompt response.  We will use only the "gold"
>In addition to metrology, we find that we have a need for doing LPCVD of
>PSG or BPSG on alumina ONLY (not on Si/Al).  Would there be any concerns
>about using alumina as a substrate in tylanbpsg?
>Stephanie Oberg
>(408) 566-1468
>-----Original Message-----
>From: Mary Tang [mailto:mtang at] 
>Sent: Tuesday, April 26, 2005 7:56 AM
>To: Oberg, Stephanie
>Cc: SpecMat at; Shi, Daniel; Lan Zhang
>Subject: Re: Measure alumina and/or Si/Al substrates on the Dektak?
>Hello Stephanie --
>Since these are pretty inert, they should be OK to measure on the gold 
>dektak system (not the "clean" one). Please be aware that the dektak has
>some measurement limitations -- check with Uli or one of the other 
>process staff members about your measurement precision needs.
>Oberg, Stephanie wrote:
>>Hi there SpecMat committee -
>>I am a new user of SNF and am interested in doing some substrate 
>>measurements: roughness, etc. Is it permitted to use alumina or Si/Al 
>>substrates for this?
>>1) ALUMINA: It is 99.6% pure tapecast alumina ceramic, highfired and 
>>polished to about 20 microinch (0.5 micron) on back and 1-2 microinch 
>>(50 nm) on front. See Kyocera pdf attached.
>>2) SI/AL ALLOY: Our other substrate to be used in the future is Osprey
>>Si/Al alloy, known as CE-7. Please see Osprey attached PDF.
>>Thanks for your help!
>>Stephanie Oberg
>>(408) 566-1468
>>soberg at <mailto:soberg at>
>>Collinear Corporation
>>   1. * Your contact information: * Name, Coral login, phone number,
>>      email address and who you work for (your PI or company.)
>>      * Stephanie Oberg, soberg, (408) 566-1468, soberg at
>>      <mailto:soberg at>, Collinear Corporation *
>>   2. * The chemical or material. * Please provide all common names,
>>      trade names, and CAS numbers where appropriate. Include an MSDS,
>>      if available; or provide the reason, if not. Make sure to
>>      include information for any new secondary chemicals (such as a
>>      developer for a new resist). Read the MSDSs as well as the
>>      Stanford Chemical Storage Groups
>>      <> and the
>>      Stanford Chemical Safety Data Base
>>      <> sections
>>      on this website to determine the Storage Group Identifier
>>      <> and Main
>>      Hazard Class
>>      <> of your
>>      chemical/material.
>>      *Alumina, alumina substrate, alumina thin film substrate, CAS
>>      1344-28-1 (No MSDS because this is not a chemical, it is just a
>>      piece of non-toxic ceramic.).
>>      Si/Al alloy, no CAS number found . (No MSDS because this is not
>>      a chemical, it is just a piece of metal alloy.)
>>      *
>>   3. * Vendor/manufacturer info: * address and phone number, website
>>      URL.
>>      *Alumina, Kyocera,
>>      Kyocera Industrial Ceramics Corp.
>>      2033 O'Toole Ave
>>      San Jose , CA 95131
>>      Tel: 408-324-0161
>>      Fax: 408-435-8327
>>      Si/Al, Osprey Sandvik,
>>      Osprey Metals Ltd.,
>>      Millands
>>      Neath. SA11 1NJ, UK
>>   4. * Reason for request: * Please give serious thought to this. If
>>      you have any process information (application notes from the
>>      vendor, protocol from another lab, experimental methods section
>>      of an article), please include it, preferably as attachments.
>>      Ask yourself these questions: Is this the latest procedure? Are
>>      there newer/safer alternatives that will also work for my
>>      project? Will any of the current SNF approved chemicals and
>>      materials work for me?
>>      *Technical requirements of our product including
>>      thermomechanical match, compatibility with high temperature
>>      (>450 deg C) processing, etc.*
>>   5. * Process Flow: * Please provide a detailed process flow
>>      description on how and where you proposed to use this chemical.
>>      This should include *all* * Lab equipment
>>      <> *to be used
>>      for processing your wafers once your new chemical or material
>>      has been used (even if your new material is a film that is
>>      removed, it may still pose potential contamination concerns.)
>>      Make sure to include wet benches. Please note that f the
>>      chemical/material is to be used in any the "clean"
>>      <>
>>      equipment, purity specifications will be needed. This is most
>>      important for chemicals/material that are not normally used for
>>      VLSI device fabrication. To be allowed into a "clean" tool
>>      <>,
>>      the material should MOS grade or better.
>>      * Currently only interested in metrology. *
>>   6. * Amount and form. * How much will you bring in? Is it solid,
>>      powder <> or
>>      liquid? (Note: as a general rule, powders
>>      <> are not
>>      permitted in the cleanroom.) Do you need to mix it to use it?
>>      *Solid substrate disks, 4" - 8" in diameter.*
>>   7. * Storage: * Will you be storing your chemical/material at SNF?
>>      If so, please note any potential reactivities (this should be on
>>      the MSDS). Storage groups
>>      <> A,B,D and
>>      L are stored in the yellow solvent cabinet in the furnace
>>      support area, while storage groups
>>      <> C, E, F
>>      and G are stored on top of one of the Pass-through Carts. Ensure
>>      your chemical container or material is properly labeled
>>      <>. If there is
>>      no available room, it must be stored by in the bulk storage
>>      area. You will then need to obtain it from receiving area
>>      personnel each time you want to use it and return it to them
>>      when you are finished using it (or each time you leave the lab).
>>      Note that there is no storage of chemicals/materials in the
>>      processing lab or at any wet bench.
>>      * No storage - will be hand carried when needed. Both materials
>>      can be stored in general storage areas such as warehouses and
>>      office supply cabinets. *
>>   8. * DIsposal * : How will you dispose of any waste or excess
>>      chemical or material? In your discussions with experts and
>>      vendors, try to determine the best way to dispose of your spent
>>      chemicals and by-products. Please refer to the SNF Labmembers
>>      Safety Manual
>>      <> for the
>>      different methods of waste disposal that are available in the
>>      *Breakage is not foreseen, since both materials are tough, but
>>      if there is breakage, I will treat is the same as broken silicon
>>      and bag it for disposal in the Sharps box.*

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

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