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Precision Vibration Isolation Systems
February 23, 2017
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Application Note
Impact of Vibration on
Advanced Immersion Lithography


Sematech




Sematech Tool

actual customer supplied data...

The 45 nanometer line-width test patterns shown were produced with an advanced Immersion Lithography System manufactured by Amphibian Systems and installed at SEMATECH in Austin, Texas. Variation between the images is due to the effect of seismic vibration on the photolithography process. The images shown were obtained using a scanning electron microscope.

With and Without STACIS

Without STACIS®

Best pattern obtained on either
the elastomer or rigid version
of original pedestal.
With STACIS®

Pattern achieved with STACIS®
active vibration isolation

The tool was initially installed on a steel and concrete plinth with a steel support structure which incorporated commercial elastomer vibration isolation pads. This pedestal did not achieve the tool’s specified vibration criteria and pattern quality was poor.

In an attempt to reduce vibration, the elastomer pads were effectively shorted out with metal shims leading to a more rigid, non-resonant structure but this resulted in little improvement. The vibration criteria were not met with either version of the pedestal and pattern quality remained poor.


ChartThe plinth support structure was removed and retrofitted with a STACIS® Active Piezoelectric Vibration Cancellation System. The STACIS® mounts were placed directly beneath the existing plinth. Supporting the tool on STACIS® resulted in a dramatic reduction of overall seismic vibration levels and achievement of the manufacturer’s floor vibration specification. More importantly, STACIS® provided a dramatic improvement in pattern quality.


* Vertical Axis Data shown

  Click for larger image

 

Photos, images, and vibration data
courtesy of SEMATECH.