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Flatness Tester

Flatness Tester
  • Flatness Tester

Slanting incidence Interference method Flatness Tester


  • Samples up to outer diameter φ200 mm are measurable.
  • Applicable to wafers (silicon, compound, oxide or glass), metallic fragments, masks, or user-defined shaped parts, etc.
  • Available to mirrored/non-mirrored surface, transparent samples, perforated samples, or atypical samples
  • Various samples are digitally measurable by analyzing interference fringe pattern obtained by laser oblique incidence interferometer through the phase shift method.

Detailed Information

Product information

  • The measured data can be quickly acquired by full surface analysis with laser light.
  • The measurement result can be displayed as measured values, contour map, bird's-eye view, cross-section view, etc.
  • Original phase shift method applicable to multiple interference fringes
  • System control with exclusive analyzer running on the Windows platform provides easy operation.
  • Transparent samples can not only be analyzed but also be measured with minimized interference of rear surface.
  • The measurement result once obtained from sample data can be re-calculated to reflect changes in perimeter exclusion range, etc.
  • Special calibration is unnecessary, pre-operation check with customer's referential samples is recommended.

Abundant options

  • Various software for each measurement of wafers, square samples, user-defined shaped samples can be selectably used.
  • Various Vacuum chucks for wafers enable High-precision GBIR (TTV) measurement.
  • Rear surface interference fringe measurement can be used as optional software for transparent samples, and enables High-precision measurement of rear interference fringe.
  • Stepper simulation and Stress analysis software to meet the demands of wafers industry users
  • Software for user-defined area enables partial measurement.
  • Various types of cradles are available for each usage.

Sample of Displays

* Click to enlarge the image. Actual screens are displayed in English.


1. Wafer


2. Disk * only FT-17


3. Square


4. User-defined shape


5. Stepper simulation for wafer (Option)


6. Stress analysis for wafer (Option)


7. User-defined area (Option)


8. Analysis of rear surface interference fringes (Option) * only FT-900


9. Data difference comparison software (Option) *only FT-900


FT-17 seriesFT-900 series
Without Fringe analyzerWith Fringe analyzerWith Fringe analyzer
Measuring methodOptical interference (Oblique incidence)
Light sourceSemiconductor laser
(655 nm, 3 mW)
He-Ne laser
(632.8 nm, 5 mW)
Sample sizeUp to φ130 mm
Up to φ100 mm for flatness measurement
Up to φ200 mm
Sample thicknessUp to 10 mm (250 µm to 2000 µm for flatness measurement)
Consultation available for requirements with other size
Sample typesWafer (silicon, compound, oxides or glass), Metallic fragments, Disks (aluminum or glass),Masks, etc.
Mirrored or non-mirrored surfaces
(excludes non-mirrored surfaces with low reflection)
Sample tilt angleVertical or Vertical tilt at 8 degree angle
Interferometer sensitivity1, 2, 3, 4, or 5 µm/fringe
(Only 1 or 2 µm/fringe on measurement with Lower surface reference,Data with 3 µm/fringe is reference)
* Only 1 µm/fringe on measurement with Lower surface reference when Sample thickness is 1 mm or more.
1, 2, 3, 4, 5, 8 or 10 µm/fringe
(Only 1 or 2 µm/fringe on measurement with Lower surface reference,Data with 3 µm/fringe is reference)
* Only 1 µm/fringe on measurement with Lower surface reference when Sample thickness is 1 mm or more.
Rear interference sensitivity-----Varies depending on
sample material
(Example: For quartz, approx. 0.275 µm/fringe)
Measuring range30 times the size of Interferometer sensitivity
(Actual value may be less, depending on
fringe condition and zoom size etc.)
Image magnification3x or higher
(manual zoom)
3x or higher
(motorized zoom)
Display resolution-----0.01 µm
Repeatability:1σ-----0.02 S+0.02 M (µm)
Condition: Setup sample uniformly then continuous measurement
S = fringe sensitivity (µm)
M = measured value (µm)
Effective pixels-----640 x 480
Measuring speed
(OS Windows® platform without graphic display)
-----6 sec or less6 sec or less
(50 sec or less on simultaneous measurement with front & rear surface interference fringe)
Measurable area
(Measurement may not be possible due to certain conditions.)
-----Whole area except 0.1 mm from the edges,
Setting step: 0.01 mm
Whole area except 0.1 mm from the edges,
Setting step: 0.01 mm
(On measurement with lower surface reference, the exception area becomes twice larger than the sample thickness,
Setting step: 0.01 mm.)
Interferometer size
(excludes protrusions)
W521 x D485 x H438(mm)W720 x D920 x H514 (mm)
Power sourceAC100 V ± 10%, 50/60 Hz, 2.4 m length power cord with B type plug
500 VA (FT-17 main unit: approx. 50 VA)600 VA (FT-900 main unit: approx. 100 VA)
Vacuum source-80 x 10³ Pa or less, 20 L/min, 1/4 tube connection
Device configurationInterferometerInterferometer + Fringe analyzer
(Personal Computer, 24 inch LCD monitor, one type of standard software,DVD±R/RW, Recipe function, Horizontal flip,Re-calculation function, 8.4-inch Interference fringe observation monitor)
Environmental conditions during use
(Temperature, Humidity, Altitude)
23 ± 3°C, 50 ± 20%RH (non-condensing)
2,000m or lower adove sealevel
WeightInterferometer(main body) :
Approx. 90 kg
Interferometer (main body) :
Approx. 90 kg
Fringe analyzer :
Approx. 30 kg
Interferometer (main body) :
Approx. 140 kg
Fringe analyzer :
Approx. 30 kg
Fringe Analyzer software
(Standard software is any one of Wafer, Disk, or Square, Others are option)
Display function-----Interference fringe, Bird's-eye view, Contour map, Cross-section view,
Measured values, Measuring parameters, Map data, etc.
Wafer-----SEMI compliant (TV, GBIR, GFLR, GF3D, GF3R, SORI), BOW, Taper
Wafer OP-----Stepper simulation, Stress analysis All Sample Data and All Measurement Data(640×480)
Disk-----P-V, RMS, TIR, VEL, ACC (FT-17)
Square-----P-V, RMS
Square OP-----Stress analysis
Common OP-----Software for user-defined area (Noncompliant to Measurement for User-defined shape)
User-defined shape-----Software for User-defined shape: P-V, RMS

The availability of the products differs from country to country depending on the status of approval in each country. Specifications and design are subject to change without notice.

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