Specific Process Knowledge/Characterization/Optical characterization

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Ellipsometer VASE and Ellipsometer M-2000V

Ellipsometer VASE: positioned in cleanroom C-1

The ellipsometer VASE is actually a M2000XI-210 ellipsometer from J.A. Woollam Co., Inc.. We call it VASE (Variable Angle Spectroscopic Ellipsometry) because it can do spectroscopic ellipsometry at variable angles.
The ellipsometer M2000V is an in-situ ellipsometer from J.A. Wollam Co., Inc. this is positioned on the Sputter System Lesker instrument for in-situ measurements.

Ellipsometry is a very sensitive characterization technique which can be used to determine thin film layer thicknesses and/or optical constants. It sends in polarized light on the surface at different angles and measures the change in polarization state of the reflected light.

It is especially good for thin films in the thickness range of a few nanometers to a few microns. The layer should be transparent to light in the usable wavelength range for the thickness to be determined. Large roughness (>40nm) and features within the field of view can cause the measurement to fail.

Ellipsometry is an indirect measurement so a model has to be fit to the data in order to obtain the film thickness and optical constants. To learn more about ellipsometry you can take a look at the tutorial provided by the J. A. Woollam Co.

Access to use the CompleteEASE software can be found using Remote Desktop connection to: 10.51.40.99 (or DCHP-D0037.win.dtu.dk)


The user manuals, quality control procedure and results and contact information can be found in LabManager:

LabManager page for Ellipsometer VASE
LabManager page for Ellipsometer M-2000V

More details

A rough overview of the performance of the Ellipsometers

Equipment Ellipsometer VASE Ellipsometer M-2000V
Purpose
  • Measure thinfilm thicknesses and optical constants for single and multilayer optical transparent thinfilms.
  • Measure opticals constants for bulk material
  • Measure growth rate of depositions done in the Sputter System Lesker.
  • Measure thinfilm thicknesses and optical constants for single and multilayer optical transparent thinfilms.
Performance Films that can be examined

Any film that is transparent to the light in the given wavelength range e.g.:

  • Silicon Oxide
  • Silicon nitride
  • PolySilicon
  • Resists
  • Polymers
  • Very thin layers of metals
  • and many more

Any film that is transparent to the light in the given wavelength range e.g.:

  • Silicon Oxide
  • Silicon nitride
  • PolySilicon
  • Resists
  • Polymers
  • Very thin layers of metals
  • and many more
Film thickness range
  • ~20Å to 2 µm (depending of the material)
  • ~20Å to 2 µm (depending of the material)
Process parameter range Wavelength range
  • 210nm-1690nm
  • 370nm-1000nm
Incident angle range
  • 45-90 degrees
  • One fixed angle - about 70 degrees
Beam size
  • 2mm (spot size on sample depends on the angle)
  • 5mm (spot size on the sample depends on the angle)
Mapping facility
  • Can make wafermaps on up to 150mm wafers
  • No mapping facility
Accessories Focusing optics
  • Focus lenses can be applied, reduces the beam diameter to 125µm
  • No focusing lenses
Transmission stage
  • Extra stage for transmission measurements
  • Base for ex-situ measurements, transmission data can be done by holding the sample up agains the detector
Substrates Batch size
  • One sample at a time smaller than 150mm (ask if you have anything larger)
  • One sample at a time, any sample size that goes in the Sputter System Lesker
Allowed materials
  • Any material that does not leave residuals on the stage and that does not evaporate
  • Any material that may go into the Sputter system Lesker



Filmtek 4000

FilmTek 4000: positioned in cleanroom C-1

FilmTek 4000 is a computerized film thickness measurement and material characterization system. This system combines fiber-optic spectrophotometry with advanced material modeling software to provide an affordable and reliable tool for the simultaneous measurement of film thickness, index of refraction, and extinction coefficient

Normal incidence and polarized 70 degree reflection data is collected and used to calculate thickness and index of refraction of the measured film using SCI’s patented Differential Power Spectral Density (DPSD) technique. Absolute reflection data is obtained by comparing sample data to the measured reflection of a known reference sample, typically a silicon wafer with a thermally grown thin oxide (~63 nm) film.

The spectrophotometer scans the sample over a predefined range of wavelengths. The software generates a reflection spectrum based on a previously stored reference scan, and then performs a regression on the unknown parameters to fit the simulated reflection and power spectral density to the observed values. The resulting thin film parameters along with the measured and modeled spectra are then displayed for the user to examine.


The user manual, quality control procedure and results, technical information and contact information can be found in LabManager:

FilmTek in LabManager


An overview of the performance of the FilmTek

Purpose Film thickness measurements and optical characterization of optically transparent thin films
  • Measurement of (multi layer) film thickness (only one unknown layer)
  • Optical constants
  • Surface roughness
Performance Thin film materials that can be measured

Any film that is transparent to the light in the given wavelength range ex:

  • Silicon Oxide
  • Silicon nitride
  • PolySilicon
  • Photoresists
  • SU8
  • Other polymers
  • Very thin layers of metals (<20 nm)
  • and many more
Film thickness range
  • <100 Å to 250 µm (depending of the material)
Process parameter range Wavelength range
  • 400-1000 nm
Substrates Batch size
  • One sample at a time - all sample larger than 5x5 mm2sizes up to 6"
Substrate material allowed
  • In principle all materials
  • Only pure silicon, silicon oxides, silicon nitrides and quartz may be in direct contact with the surface of the stage. If you have metals, III-V materials or polymers on the back side of the substrate the please mount your sample on a silicon carrier wafer.




Comparison of the two methods

For comparison of the three methods, see here: Film thickness and optical constants of optical transparent films