Archived posting to the Leica Users Group, 1999/01/10

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Subject: [Leica] Steppers & steppers...
From: Berg Na <bergna@yahoo.com>
Date: Sun, 10 Jan 1999 22:04:05 -0800 (PST)

Alexey Merz alexey@webcom.com wrote:

<<...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...>>

You are comparing micro-actuators which are based on stepper motors
and optical step-and-repeat mask aligners which are also commonly
referred to as steppers. Applied Precision Instruments makes
microscopes for live-cell fluorescence microscopy used for biological
diagnostic applications which are not even remotely related to the
step-and-repeat masks aligners used in IC fabrication. API also makes
linear actuators (with 10 nm positioning resolution) and probe cards
analyzers for the semicondutor industry but again, they do not make
the kind of steppers that Intel uses to build its Pentiums.

<<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.>>

There are simply no basis for comparison between AFMs which are
basically high resolution microscopes and steppers which are used to
project microscopic images with absolute fidelity.

Berg

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