Variable angle stokes laser ellipsometers L116S300 and L115S300

 Variable angle stokes laser ellipsometer L116S300 description
The model L116S300 with convenient USB interface uses advanced StokesMeter™ technology (previous winner of  Photonics Spectra and R&D 100 best new products awards). The unit's simple robust design offers unprecedented ease of use and instantaneous measurement. It is a popular alternative to overly complicated and less precise spectroscopic ellipsometers for unparalleled routine measurement.

Unlike other ellipsometers, StokesMeter™ technology uses no moving parts and no modulators to quickly and accurately determine the complete polarization state of the laser measuring beam at a 70° incidence angle. The laser light source has ample light intensity for increased measurement accuracy of absorbing and rough scattering films. The HeNe Gas Laser source is spectrally precise, stable and long lasting. Use of a laser source permits optimum instrument design employing optics, detectors and other components so that measurements can be made highly accurate. The L116S features a small footprint yet it can accommodate large samples up to 300mm. The sample stage can be locked in place or easily moved by hand to measure any point on the sample surface. The high quality stage includes a manual tilt and table height adjustment using an alignment screen on the computer giving highly repeatable measurements.

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

features

• Trouble-free, no moving parts advanced StokesMeter™ measurement head.

• Measures complete state of polarization providing increased accuracy.

• Accurate, stable measurements using spectrally precise laser ellipsometry.

• Fastest possible instrument for thin film measurement.

• Tilt-free, focus free, hands-off operation for similar wafers.

• 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 L116S300.

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 providing increased measurement accuracy.

 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-USB Stokes Ellipsometer is an excellent value in a basic uncomplicated ellipsometer. The LSE-USB model 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  port. 

L116S300 can be equipped with the following  options:

Optional WIN 11 Laptop PC  
With preloaded drivers and software. 

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

 variable angle stokes waferskan™ ellipsometer L115S300

 300mm stokes variable angle waferskan™ ellipsometer
The model L115S Stokes Variable Angle WAFERSKAN Ellipsometer is a high speed film thickness mapping system measuring one site per second including stage travel! It uses advanced StokesMeter™ technology (previous winner of Photonics Spectra and R&D 100 best new products awards) to give tilt-free, focus free, 2D/3D color thickness and index images on any size wafer up to 300mm . The units' elegant design offers unprecedented ease of use and instantaneous measurement at a cost much lower than conventional production control metrology systems. Affordably priced the L115S300 is a popular choice in a high precision scanning ellipsometer. 

high accuracy and performance
The model L115S300 builds on the production proven Gaertner WAFERSKAN™ line of ellipsometers in widespread use throughout the world. From thin gate oxides only tens of angstroms thick to thick polyimides and photoresists Gaertner has earned a reputation for providing precise, reliable results. The model L115S300 sets a high performance standard to meet today's more demanding metrology applications.

great graphics 
The measurement results are displayed on the computer monitor and can be sent to a printer. Results stored in a text data file are displayed in a 2D contour or 3D Map images. The images can be rotated, tilted, reduced or enlarged for immediate viewing and interpretation.

2D contour image map of film thickness 3D contour image map of film thickness

Main Screen

 easy to use
The L115S300 Variable Angle Stokes WAFERSKAN™ is simple to operate. The user interacts with a single main program screen so the set up is easy to understand and the measurement can be quickly made. Stored recipes are readily accessed for scanning different films and patterns. Similar wafers are automatically scanned with a single mouse click. The operator can chose 1, 5, 9, or 49 point circular measurement,  X-Y grid, diameter, or Polar Scans with up to 1000 measurement points and set the wafer edge exclusion. 

high precision stages
High quality Newport stepping motor stages provide precise and repeatable positions. The wafer is held on the optically flat table by vacuum. The stages move automatically in rapid yet precise steps under programmed computer control. Measurement time is less that one second per point including stage travel. Step precision is better than 10 microns, with the area of coverage and points within that area easily set for automatic scanning.

speed and stability
The L115S300 Ellipsometer measures by reflecting a polarized laser beam from the sample surface at a 70° incident angle and determines the change in polarization caused by the sample virtually instantaneously. Since there are no moving parts in the StokesMeter™ measuring head the measurements are accurate and repeatable even after many months of continuous use. Precision of measurement is further enhanced by the use of a stable, spectrally precise, high signal to noise HeNe gas laser light source.

 stokes variable angle waferskan™ ellipsometer L115S300 specifications

Alignment: Tilt and table height via computer alignment screen. Proprietary tilt and table height system . corrects for ordinary sample tilt and out of-flatness with no need for sample readjustment or . . complicated, costly and slow autofocusing systems.
Incidence Angle: 30°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 90° Manually selectable
Method of Measurement: Advanced StokesMeter reads the complete beam polarization using no moving parts and no . . . modulators, only 4 stationary
silicon detectors so measurements are exact and stable.
Measurement Time: One second per point including stage travel.
Measurement Laser: Spectrally precise, stable, long lasting HeNe 6328A Laser with a 15 x 45 micron spot at 70 . . . . Typical lifetime is over 3 years. Similar light source used by NIST to calibrate standards.
Alignment Laser: 670 nm Laser Diode
Software: 2D/3D color graphics runs under Windows™ included
Sample (Wafer) Size: Up to 300mm diameter standard. Vacuum held (requires 5 inch Hg.).
Stages: Precision Newport Stepping Motors under user programmed computer control with manual . . . . pushbutton override. 150mm linear and 360° rotary motion covers any point on the sample. . . .. Tiltable table permits correction for sample out-of-flatness up to 1° in both X and Y planes. Map .. . any size wafer up to 300mm at 1 second per point.
Stage Precision: Within 10 microns
Data Output: 2D/3D color images of film thickness, refractive index and location to monitor, file or printer. Text . .. data file is easily exported to other programs.
Computer: Windows™ 11 Laptop PC included
Film Thickness Range: 0 - 60,000 Angstroms on substrate or on 1, 2 or 3 known sublayers
Precision & Repeatability: Sub-Angstrom over most of the measurement range.
Refractive Index: ± .0005 over most of the measurement range.
Power: 115V, 100V, 220V, 240V (50/60 Hz)
Dimensions(LSE-WS): Height: 18 inches Width: 28 inches Depth: 20 inches
Net Weight: 85 lbs. Shipping Weight: 200 lbs.
CE Compliance: S series Ellipsometers comply with European safety directives and carry the CE mark.
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.
Warranty: 1 year warranty covers all parts and labor exclusive of shipping costs