Frequently Asked Questions

Benchmark Technologies’
Phase Shift Focus Monitor (PSFM) Analysis Tools

 The PSFM Reticle

With over 300 users world wide, Benchmark’s Phase Shift Focus Monitor (PSFM) Test Reticle is the standard by which lithographers evaluate scanner and stepper focus and lens performance. Use of the PSFM Reticle:
Advantages over Other Methods
  • Enhances lithography-tool performance
  • Improves overall throughput by reducing lithography tool downtime for focus-related preventative maintenance
  • Evaluates and compares new and installed lithography tools using a common method
The Phase Shift Focus Monitor Reticle is the only commercially available product that makes use of patented phase shift technology. It meets today's demanding requirements for critical process monitoring with rapid and accurate evaluation of focus-related errors.
 
APPLICATIONS
  • Determine best focus
  • Characterize lenses, including lens heating, field curvature, tilt, astigmatism and coma
  • Evaluate autofocus/autoleveler performance
  • Evaluate wafer chuck flatness
  • Identify process induced focus defects
HOW THE PSFM RETICLE WORKS

Benchmark’s Phase Shift Focus Monitor Reticle uses several cells of phase-shifted patterns.

These cells primarily consist of box-in-box and L-bar structures, which allow the use of metrology tools to automatically extract data quickly and accurately.

Each structure within the focus monitor cell uses equally spaced chrome lines positioned between phase-shifted and unshifted areas (see illustration).

These IBM-patented phase-shifting structures produce images whose placement shifts according to their magnitude of defocus. When the patterns are imaged in focus, no shift or overlay error is seen. When the patterns are not printed at optimum focus, significant shifts appear:

  • Positive defocus shifts the image toward the phase shifter.
  • Negative defocus shifts the image away from the phase shifter.
PSFM DATA!TM Focus Analysis Software
 

PSFM Data! Focus Analysis Software is designed for litho engineers who use PSFM reticles to efficiently monitor the performance of critical litho tools.

  • Imports raw overlay data in any major metrology tool format.

  • Performs calibration curve fitting, best focus, astigmatism, tilt computation and analysis.

 

PSFM DATA!TM SPC (Automated Focus Analysis Module)

 

Benchmark can assist users with integrating the output from PSFM Data!™ with their production statistical process control tools.

 

 

For more information click here

  
       
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