Woollam M-2000 Ellipsometer

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Woollam M-2000 Ellipsometer
Equipment Details
Technology Metrology
Materials Restriction General
Sample Size pieces up to 6" wafers
Equipment Manual
Overview System overview
Operating Procedure SOP
Supported Processes Supported Processes
Maintenance Maintenance

The Woollam M-2000 is a spectroscopic ellipsometer capable of extracting thickness and index of refraction for transparent and semi-transparent thin films or coatings. It is equipped with fully automated sample alignment with stage tip/tilt and focus. It has a high speed CCD detector for collection of data across the full spectral range of 193-1683 nm simultaneously. Typical acquisition time is 5 sec per site per angle.


None at this time.


  • Thickness range: From 10 Å to several μm (Note: Maximum thickness is film dependent.)
  • For very thin films (less than ~150 Å), ellipsometry loses sensitivity to optical constants. To measure the thickness of these films, the model for n and k must be assumed or determined from a thicker sample (assuming the optical constants are the same for both thick and thin samples).
  • Since only two values are being measured at each wavelength, only two unknowns can independently be solved at each wavelength (thickness and n, n and k, thickness1 and thickness2, etc). This must be kept in mind when building and fitting a model to the data set. If too many unknowns are included in the model, the fitting result may not be valid or unique.
  • For absorbing films, the film must be thin enough so it is not opaque. Metals thicker than ~1000 Å are typically opaque for reflection measurements.
  • In addition to standard ellipsometry measurements, this tool can be used for:
    • Transmission intensity measurements for samples with transparent substrates
    • Angled reflection intensity measurements
    • Contact the tool owner by submitting a Helpdesk Ticket for support of these measurements.

System overview

Hardware details

  • Wavelength range: 193-1683 nm
  • Variable angle range: 45 to 90 degrees
  • Spot size: (3 mm diameter)
    • Without focusing optics is 3 mm x 12 mm @ 75 degree angle of incidence
    • With focusing optics is 300 μm x 1.2 mm @ 75 degree angle of incidence.
      • Note: Focusing optics are available for use with staff assistance.
  • Sample Stage Size: 6” for 150 mm wafers and smaller samples

Substrate requirements

  • Sample must be > 3 mm x 1.2 cm in size to accommodate beam size without focusing optics. (300um x 1.2mm with focusing optics)
  • Maximum sample thickness ~15mm
  • Substrate types:
    • Material files for various substrates are available including silicon, germanium, GaAs, glass, and others.
    • Single side polished substrates should be used if possible to avoid issues with backside reflections.

Material restrictions

The Woollam M-2000 Ellipsometer is designated as a General class tool. Below is a list of approved materials for the tool. Approved means the material is allowed in the tool under normal circumstances. If a material is not listed, please create a helpdesk ticket or email info@lnf.umich.edu for any material requests or questions.

  • No liquids or uncured spin on films. Nothing that will stick to the stage or leave a residue behind. Other than that, there are no restrictions.

Supported processes

  • There are automated recipes available on the tool for wafer map characterization of a number of thin film depositions in the LNF.
  • If there is a common use recipe you would like to have added to the tool, please submit a Helpdesk Ticket to contact the tool owner.

Standard operating procedure

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Checkout procedure

  1. Read through this page and the Standard Operating Procedure above.
  2. Create a Helpdesk Ticket requesting training.
  3. A tool engineer will schedule a time for initial training.
  4. Practice with your mentor or another authorized user until you are comfortable with tool operation.
  5. Schedule a checkout session with a tool engineer via the helpdesk ticket system. If this checkout is successful, the engineer will authorize you on the tool.


Lamps changed and system alignment calibrated as needed.