[labnetwork] Backside Alignment Microscopes

[Demis D. John]

IR camera is our method of choice for BS alignment verification
<https://wiki.nanofab.ucsb.edu/wiki/Suss_Aligners_(SUSS_MJB-3)#Backside_Alignment>
here, through silicon wafers. Although we've never needed to measure the
misalignment, just coarse verification.
We found a cheap IR cam that uses a computer monitor to view.

Since you already have an IR camera installed, may I suggest a possible
quick-fix to the problem of calibrated measurements using your existing
setup:
- Buy a Coax splitter and/or Coax-->USB digitizer (don't go ultra cheap or
the device will die in <6 mo.).  Examples
<https://www.amazon.com/s?k=coaxial+to+usb+adapter&channelId=500&clpRedir=Y&plpRedirect=mhFallback>.
This will hopefully then have a fixed magnification for every objective on
your MA6.  Videogamers use this kind of thing for streaming, so there
should be options.  Hook it up to a cheap laptop (again not *too* cheap or
the laptop can't keep up with the live framerate.)
- Use a microscope calibration slide
<https://www.google.com/search?sca_esv=2bd2cc07c427a574&sxsrf=APpeQnv3NA0RGJ6wFFr05l5ixbztmIwhCg:1783120742656&udm=28&fbs=ABfTbFVyMZGZf1hfvX9uKjN_-G8cqCQj_06QnZs315LoFmPf5bBLHMJ0vMQmTbuI72DM7jnxvATrUU2Yg9dwuUGnsUHcA8ltRxGSueAm4xbJB7-U9Vk4K2G3aCoTcvC5pL-W3Bc4wKvyblIDvW9t3J41edOYhCyumrIO3nro7L99GH8kliwMVqQ0hvbksXIL7xFJBI_8mwByDhHJj3T0-O3ElCMyZrfalw&q=microscope+calibration+slide&ved=1t:220175&ictx=111&biw=1142&bih=844&dpr=2.2>
to calculate µm-per-pixel calibrations for each magnification/objective.
- Use something like AMscope software
<https://wiki.nanofab.ucsb.edu/wiki/Measurements_and_Imaging_with_Amscope_Camera_-_Quickstart_Usage_Guide>,
or FIJI <https://imagej.net/software/fiji/> + Microscope Measurement Tools
<https://wiki.nanofab.ucsb.edu/wiki/FIJI_-_Microscope_Measurement_Tools> plugin
to apply the calibrated measurements to acquired IR images.  (I stopped
maintaining Microscope Meas tools a while ago - hopefully someone's newer
fork/update works!).

-- Demis (contact info <https://wiki.nanotech.ucsb.edu/wiki/Demis_D._John>)
*Reminder*: The NanoFab has a publications policy
<https://wiki.nanotech.ucsb.edu/wiki/Frequently_Asked_Questions#Publications_acknowledging_the_Nanofab>


On Fri, Jul 3, 2026 at 2:31 PM Jeff McKay <jeffmckay at g.ucla.edu> wrote:

> @Kyle - Thanks for suggestion, but we are looking into more benchtop
> microscope tools
>
> @Demis - For MA6 verification we have installed a halogen bulb on the
> bottomside and IR camera installed on topside for verification alignment.
> It is crude and built into the MA6 system and we are not able to pull
> images directly from it (cell phone images of the monitor....), we do use
> splitview and backside/frontside objectives during exposure though.
>
> @Owain - Thanks, we have contacted our Nikon vendor and have encountered
> some slowness in getting the ball rolling.... Are you able to share any
> specific model#s for IR cameras and lamps that are attached to your scope?
>
> Thank you all,
> Jeff
>
>
> On Fri, Jul 3, 2026 at 9:31 AM Owain Clark <odc1n08 at soton.ac.uk> wrote:
>
>> Hi Jeff, we have been having some success with Nikon microscopes and
>> automated stages (Marzhauser) then scripting NIS-Elements to acquire data.
>> I expect automated data extraction would be possible from line slice
>> intensity plots. Currently the users have managed to develop automated die
>> grid inspection macros based on some example macros given by Nikon, anyone
>> with a basic level of coding can get stuck in, API is C style syntax. I
>> just made sure I had bullet proof hardware interlocks to prevent lens
>> collisions in place first as it turned out joystick control of Z bypasses
>> software soft limits, obvious in hindsight as it talks direct to motor
>> controller.
>>
>>
>>
>> Another nice part of the s/w is that the image stitching (mosaics) works
>> quite well, so if you need high dpi resolution on larger images it’s an
>> easy way – all callable from macros also. Or put a DS10 camera on and enjoy
>> up to 24MP images per FoV.
>>
>>
>>
>> I’m quite happy with this system, people are using it increasingly for
>> automated in line quality steps throughout processing, our enterprise teams
>> like it for the customers that demand quality inspections of every step.
>>
>>
>>
>> O.
>>
>>
>>
>> *From:* labnetwork <labnetwork-bounces at mtl.mit.edu> *On Behalf Of *Jeff
>> McKay
>> *Sent:* 02 July 2026 22:17
>> *To:* labnetwork at mtl.mit.edu
>> *Subject:* [labnetwork] Backside Alignment Microscopes
>>
>>
>>
>> You don't often get email from jeffmckay at g.ucla.edu. Learn why this is
>> important <https://aka.ms/LearnAboutSenderIdentification>
>>
>> *CAUTION:* This e-mail originated outside the University of Southampton.
>>
>> Hello All,
>>
>>
>>
>> We currently use Karl Suss MA6 for lithography on the backside of 4" InP
>> wafers. It is critical that we have good back to front side alignment, and
>> right now we can only use the MA6 to verify alignment.
>>
>>
>>
>> Unfortunately there is no scale/camera options for outputting to get
>> quantative data from our alignment.
>>
>>
>>
>> We are looking for a bench top tool/microscope that would allow us to
>> check alignment after development so that we are getting higher resolution
>> and more quantative results. Does anyone have any recommendations?
>>
>>
>>
>> Thanks,
>>
>> Jeff McKay
>>
>>
>>
>> Process Engineer
>>
>> Global Communications Semiconductor
>>
>> Torrance, CA
>>
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