Data and Analysis Storage.
- Microsoft ExcelTM spreadsheets and
- Report and graphics are stored in the data
- Reports and graphics can be directly saved to web
sites using html format
- Full user-access is provided for all raw,
calculated and modeled data.
Weir PSFM is a focus calibration, modeling and control
software suite for use in semiconductor development as well as process
and exposure tool fabrication control. Weir PSFM provides all the tools needed for characterization
and control tasks associated with focus analysis in advanced
Weir PSFM consists of three modules:
- Weir Layout
- An interactive graphics interface for
specifying focus, dose, Numeric aperture, partial coherence and
reticle scan direction as a function of the exposure layout on
one or more wafers.
- A graphic interface for fine-tuning die size,
- Weir PSFM Calibration
- Calibrate measured pattern offsets to
exposure tool focus
- The Weir Focus Template library stores
calibrations for every feature-site on the reticle
- Verifies reticle design and manufacture
- Calculates the precision of focus calucation
- Calculate and derive the "Best Focus" field
for the lens and reticle. The Best Focus is a measure of the
focus errors present in the exposure tools wavefront.
- Model the "Best Focus" of the exposure tool
to determine lens aberrations, reticle scan perturbations, bow
and tilt of the reticle platen.
- Weir PSFM Fixed Focus
- Use the Weir Focus Template library to
convert measured reticle-feature offset data to defocus values
across one or more wafers.
- Plot vector, contour and XY plots of the
wafer's raw focus perturbations.
- Examine radial and edge bead errors in the
- Model whole wafer, field, lens-slit and
reticle scan focus errors.
- Calculate height/ focus errors in wafer
surface uniformity, bowing, Wafer Tilt, wafer-stage autofocus &
- Examine reticle scan-direction sensitivity,
lens aberrations, field-tilt stability, reticle bowing during
loading and scan and reticle deformation during heating.
- Automatically remove average field, lens slit
or reticle scan components.
- View "What if" scenarios using simulations to
remove focus offset, tilt, bow etc. and focus your engineering
efforts to the corrections that provide the greatest advantage.
Use the Weir PSFM software suite to measure and
- Lens and scanner wavefront behavior
- Wavefront and lens aberration characterization
- Full-field and/or scanner-slit process window
- Wafer and photoresist uniformity
- Separate wafer and reticle stage tilt
- Reticle-scan stage travel stability
- Astigmatism mapping and
- Reticle-enhancement element qualification.
Weir PSFM automatically imports and converts feature
measurements from SEM’s, Scatterometry, Electrical Linewidth Metrology
(ELM), other optical and X-ray tools. Automated and manual-interactive
data culling methods are fully employed. Output can be on paper or
binary format with control surface element-outputs to exposure tools and
A “Weir” is defined as an “obstruction placed in a
stream, diverting the wavefront through a prepared aperture”. The Weir
PSFM analysis provides tools to optimize and characterize the image
wavefront and it’s aberrations. A full library of user-selected models
are provided for the wafer and exposure tools. Model outputs can be
controlled and applied to the data to determine the effectiveness of
tool corrections through simulation to optimize wavefront performance.
Data import from any data source is supported using
simple windows controls. The system is an “open” tool with data stored
and easily accessed for user extended analyses using Microsoft Excel
Spreadsheets. Worksheet macros are not used for the analysis but the
user can add their own if desired. The analysis will automatically
determine lens and system aberrations for the stepper and scanner.
Weir PSFM is a compiled application with a full object oriented,
mouse-interactive interface. The software is functional on Windows 2000
and Windows XP etc.. Microsoft Excel is required.