stokes laser ellipsometer LSE-2A2W






stokes laser ellipsometer LSE-2A2W Two Angle Two Wave description
uses a red laser at 70° and a green laser at 60° incidence angle combined in a single measurement.  The dual 2 angle 2 wave  measurement determines thicker film thickness and refractive index values over a wider thickness range.  Helps with difficult to measure films and gives many of the advantages of spectroscopic ellipsometers without the complexity.  

The Stokes Ellipsometer LSE-2A2W, with convenient USB interface, uses advanced StokesMeter™ technology (previous winner of  Photonics Spectra and R&D 100 best new products awards) with no moving parts and no modulators to quickly and accurately determine the complete polarization state of the measuring beam. Select a single measurement with the red 633nm laser at 70° or a single measurement with the 544nm green laser at 60° or a combined measurement using both lasers at both angles simply via computer keyboard.. The measurements are rapid and precise with no moving parts. The units' simple robust design offers ease of use at low cost.and is a welcome alternative to overly complicated ellipsometers.

The laser light sources have ample light intensity for increased measurement accuracy of absorbing and rough scattering films. Laser sources have the added advantage of being spectrally precise, stable and long lasting. Their use permits optimum instrument design in optics, detectors and other components so that measurements can be made highly accurate. The space-saving design features a small footprint yet it can accommodate large samples up to 300mm wide. The sample stage can be easily moved by hand to measure any point on the sample surface. The sample table includes a manual tilt and table height adjustment which is set using an alignment screen on the computer.

high speed film thickness measuring system measures in less than a second!


  • Tilt-free, focus free, hands-off operation for similar wafers.
  • Fastest possible instrument for thin film measurement.
  • Trouble-free, no moving parts advanced StokesMeter™ measurement head.
  • Measures complete state of polarization useful for rough, scattering samples.
  • Accurate, stable measurements using spectrally precise laser ellipsometry.
  • Simple, compact tabletop instrument - competitively priced.


gaertner ellipsometer measurement program LGEMP description
The LGEMP Windows software is versatile and can measure single layer films such as oxides, nitrides and photoresists as well the top layer on a known 1, 2, or 3 layer stack such as poly on oxide and oxide on poly on oxide.  Monolayer organic films are an excellent application for the precision and stability of the model LSE.

A "File Handler" enables saving and quick retrieval of frequently used measurement setup parameters. Four user-defined setup files can be assigned to one step "press-and-go" shortcut buttons for  fast access of different measurement setups.


The Enlarged PSI-Delta  Map within the LGEMP program permits theoretical "what if" type simulation of your Thin Film Model  providing a deeper understanding of the film modeling.  The top layer film Thickness T1(pink line), Refractive indexNf1(red line), Absorption Kf1(brown line),  Y(yellow line),  D(green line), with moveable sliders on the left side quickly show the effects of varying the model parameters on the film refractive index resolution and measurability.  The aqua color lines are lines of constant film refractive index Nf1.  The white lines are regions of Autofix of Nf1 where the index is not easily resolved in this region. 

description of stokesmeter™ technology
This advanced device uses no moving parts and no modulators to quickly and accurately determine the complete polarization state of the measuring beam.

The diagram above shows the StokesMeter™ photopolarimeter for the simultaneous measurement of all four Stokes parameters of light. The light beam, the state of polarization of which is to be determined, strikes, at oblique angles of incidence, three photodetector surfaces in succession, each of which is partially spectrally reflecting and each of which generates an electrical signal proportional to the fraction of the radiation it absorbs. A fourth photodetector is substantially totally light absorptive and detects the remainder of the light. The four outputs thus developed form a 4x1 signal vector I which is linearly related, I=AS, to the input Stokes vector S. Consequently, S is obtained by S=A(-1)I. The 4x4 instrument matrix A must be nonsingular, which requires that the planes of incidence for the first three detector surfaces are all different. For a given arrangement of four detectors, A can either be computed or determined by calibration.

technological advantage
The simple, compact StokesMeter™ replaces a typical rotating analyzer assembly consisting of a drum, prism, encoders, switches, motor and detector and their associated electronics. In addition, the waveplate mechanism on the polarizer arm, is eliminated resulting in a fast, precise, no moving parts ellipsometer.

An outstanding feature is the Stokes Ellipsometer's compensation for small changes in angular beam deviation caused by sample out-of-flatness; thus permitting fast, uninterrupted measurement over the entire wafer surface without the need to pause to correct for focus and tilt. .

Extremely precise and stable the model LSE-2A2W Stokes Ellipsometer is an excellent value in a basic uncomplicated ellipsometer. The LSE-2A2W ellipsometer ships complete with LGEMP Windows™ software, USB cable, 6 inch sample stage and reference wafer. It interfaces to your Windows™ PC or Laptop with a USB 2.0 port. 

LSE-2A2W can be equipped with the following  options:

Optional 8 inch Sample Stage  L8  $ 0.5 K 
Substitutes 8 inch sample stage in place of standard 6 inch sample stage

Optional WIN 10 Laptop PC  
With preloaded drivers and software and security cable 

Optional Stokes Calibration Kit L118-KIT 
Recalibrate any Stokes Ellipsometer using 4 Gaertner traceable wafers plus glass $ 2 K (L118G-KIT) or
4 NIST traceable wafers plus glass $ 3.5 K (L118N-KIT).  Most users will not require ellipsometer recalibration.  Intended for the most exacting semiconductor manufacturers with extremely tight tolerances and regulatory compliant users.

stokes ellipsometer LSE-2A2W specifications

Alignment: Manually adjusted tilt and table height using the computer alignment screen.
Incidence Angle: 60° for 544 nm laser and 70° for the 633nm laser
Method of Measurement: Advanced StokesMeter determines the complete measuring beam polarization using no moving parts and no modulators, only 4 stationary silicon detectors so measurements are stable and exact.
Measurement Time: Practically instantaneous
Measuring Lasers: 544 nm and 633 nm HeNe gas lasers with 1 mm beam diameter 
Alignment Laser: 670nm Laser Diode
Sample (Wafer) Size: 300 mm wide X unlimited length
Stage: 6 inch hand positioning table with tilt and table height adjustment.
Software: Windows™ LGEMP 4 layer program included.
Required Computer: Windows™ desktop or laptop with USB 2.0 port (not included) 
Film Thickness Range: 0 - 60,000 Angstroms on substrate or on 1, 2, 3, or 4 known sublayers.
Precision & Repeatability: Sub-Angstrom over most of the measurement range.
Refractive Index: ± .0005 over most of the measurement range.
Power: 100V-240V,  50-60Hz.  1 A
Dimensions: Height:  16.5   Width: 27.5   Depth: 16 inches
Net Weight: 45 lbs.  Shipping Weight: 65 lbs.
CDRH Compliance: All laser ellipsometers supplied by Gaertner comply with CDRH requirements 21CFR 1040 for a Class II laser product emitting less than 1 mW or Class IIIb less than 5 mW of low power radiation. As with any bright source such as the sun or arc lamp, the operator should not stare directly into the laser beam or into its reflection from highly reflecting surfaces.
CE Compliance: Stokes Ellipsometers comply with European safety directives and carry the CE mark.
Warranty: 1 year warranty covers all parts and labor exclusive of shipping costs

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