Particles Re: Appointment for wafer inspection

Jim McVittie mcvittie at cis.Stanford.EDU
Thu Apr 21 15:06:58 PDT 2005


I inspected Ankur's wafer this afternoon. I was surprised on how drity it 
was. It had finger prints all over and it was loaded with particles. He 
claimed the particles and finger prints were from the a carrier wafer to 
the back. He did not seem to know anything about using dark field or the 
black lamp for looking at particles. Putting wafers like his into clean 
etchers can't be good for the users trying to do clean work. It seems 
to me we should have some standard in terms of gross particles for 
wafers going into our tools. A simple black light or dark field inspection 
would be good enough. Maybe we could do wafer inspections at several 
point in a first process for new users.


On Thu, 21 Apr 2005, Ankur Jain wrote:

> Hello Dr. McVittie,
>  As per SpecMat instructions given to me (please see note below), I would
> like to show you a wafer which I did DRIE on yesterday. What would be a
> good time for you? I'd appreciate it if we could do this as soon as
> possible. I am available any time Thursday after 2 pm, including late
> night, and any time on Friday.
> thanks,
> Ankur
> ---------- Forwarded message ----------
> Date: Thu, 10 Mar 2005 08:28:03 -0800
> From: Ed Myers <edmyers at>
> To: Ankur Jain <ankurjn at>
> Cc: rissman at, maurice at
> Subject: Re: Addendum to my request
> Ankur,
> SpecMat has reviewed your process.  We have the following comments
> regarding your request.  First, the clean prior to step 2, Al deposition in
> the gryphon can not be done at WBMetal, it needs to be done at WBGeneral in
> beakers.  Also, while you can use the gryphon for metal deposition, please
> do not use any sputter etch.  Finally, Jim McVittie would like to inspect
> your wafer following the deep reactive ion etch step.  Please contact Jim
> and arrange this inspection.
> Regards,
> At 01:51 PM 2/18/2005, you wrote:
> >Hello SpecMat members,
> >  Following discussions with Ed Myers and Jim McVittie, I would like to
> >propose two alternatives to the way I was planning to doing the DRIE in my
> >structure. These alternatives are (1) leaving 20-30 um of Si during the
> >STS etcher and completing the etch in drytek1, or (2) growing a layer of
> >thermal oxide prior to NiTi sputter and using that as an etch stop for
> >DRIE.
> >  I am attaching a powerpoint file explaining these two alternatives. I
> >will be happy to adopt either of the alternatives if that helps me run the
> >proposed process.
> >  Please let me know if there are any questions.
> >
> >
> >regards,
> >
> >Ankur.
> >
> >*************************************************************************
> >Graduate Student
> >Microscale Heat Transfer Laboratories         Residence:
> >Room 201, Building 530                        126 Blackwelder Ct, Apt 902
> >Stanford, CA-94305                            Stanford, CA - 94305
> >Ph: 650-736-0044                              Cell Ph: 650-799-8986
> >

Jim McVittie, Ph.D.    			Senior Research Scientist 
Allen Center for Integrated Systems     Electrical Engineering
Stanford University             	jmcvittie at
Rm. 336, 330 Serra Mall			Fax: (650) 723-4659
Stanford, CA 94305-4075			Tel: (650) 725-3640

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