Re: [Leica] Re: Mechanical precision

[Alexey Merz <alexey@webcom.com>]

"William Davis" <wishda@weblnk.net> wrote:

>Yet Nikon and Canon still manufacture machines called steppers that
>feature a lens that can focus down to a micron. They are used to etch
>microchips.

>Whenever you see news footage of people in bunny suits making>
>microchips at Intel, they are usually working near a machine with a
>Canon or Nikon logo. I have heard these machines described as some of
>the most precise pieces of equipment made by mankind.

Not true, as we'll see...

>As someone else pointed out on another photo forum, both Nikon and
>Canon make the majority of profits from the sale and upkeep of these
>machines. It would not be far off to say they are stepper
>manufacturers who make photo equipment for nostalgic reasons.

Zeiss, too. But the winner in the mechanical motion control 
is a company here in the Pacific Northwest. 

Applied Precision Instruments in Seattle makes steppers with 
a repeatable absolute accuracy of 10 nm over a greater than 20 mm 
range of movement. These units are being used in the semiconductor
and biotech industries. State of the art - enough so that Nikon 
came to API looking for a partner to assemble a state of the art
oprtical microscopy system. We will take delivery on API's second 
Nikon unit to be shipped in about six weeks. Nikon even lets API 
select the *specific* objective lenses to be shipped. The sample
stage on the 'scope uses API's motion control technology in all
three axes, and the optical capture system uses a cooled CCD camera,
with the data piped into an SGI workstation for image deconvolution
and other processing steps. Needless to say, I'm excited about this.
Resolution is 0.1 um normal to the optical axis, 0.3 um along the
optical axis. This is within a few percent of the theoretical limits
for visible light microscopy.

And yet...
Even higher resolution is obtained with piezoelectric controls, 
which are used to move the tips of scanning microscopes (AFM*s 
and their relatives) with sub-nanometer resolution. And IBM
leads the field in AFM technology. (One of my old roomies is 
finishing up his PhD in Chemical Physics at Harvard, where he's 
used an IBM-designed AFM to study the mechanical properties of 
single carbon nanotube molecules; he likes to give me a hard 
time about the lousy resolution of optical microscopy.) 

So I'd have to say that AFM's are by far the most precice pieces of 
equipment yet made by mankind; they allow the movement and placement
of single atoms, and put the best UV photolithography to shame.

* Atomic Force Microscope
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Alexey Merz | URL: http://www.webcom.com/alexey | email: alexey@webcom.com