3D - Optical Surface Profilometer Laboratory

Phone : 91-3222-269934

Location : NB / FF / 3, CRF

Facilitator : Prof. Jyotsna Dutta Majumdar, Metallurgical & Materials Engineering
Email: jyotsna@metal.iitkgp.ernet.in, Contact:+91-3222-283288



Objectives

To measure the surface profile in order to quantify its roughness critical dimensions as step, curvature, flatness from the surface topography.

 

People

Prof. Jyotsna Dutta Majumdar
Facilitator
Metallurgical & Materials Engineering
jyotsna@metal.iitkgp.ernet.in
+91-3222-283288

Equipment Details

3D-Optical surface profilometer

Manufacturer- Bruker

Model- Contour GT

Year of Installation- 2014

  

Specifications
 Max. Scan Range Up to 10 mm

 RMS Repeatability (PSI)

 0.02 nm*
 Lateral Resolution

0.38 μm min (Sparrow criterion);

0.26 μm (with AcuityXR®)
 Step Height Accuracy < 0.75%**
 Step Height Repeatability < 0.1% 1 sigma repeatability
 Max Scan Speed 47 μm/sec (with standard camera)
 Sample Reflectivity 0.05% - 100%
 Max. Sample Slope

Up to 40° (shiny surfaces);

Up to 87° (rough surfaces)
 Sample Height Up to 100 mm (4 in.)
 Sample Weight Up to 4.5 kg (10 lb)
 XY Sample Stage 150 mm (6 in.) manual or automated option
 Tip/Tilt Function ±6° manual in stage
 Optical Metrology Module

Patented dual-LED illumination;

Single-objective adapter;

Optional automated or manual turret;

Single or auto FOV lenses
 Objectives

Parfocal: 2.5x, 5x, 10x, 20x, 50x, 115x

LWD: 1.5x, 2x, 5x, 10x

TTM: 2x, 5x, 10x, 20x

Brightfield: 2.5x, 5x, 10x, 50x
 Available Zoom Lenses 0.55x, 0.75x, 1x, 1.5x, 2x
 Camera

Standard monochrome: 640 x 480

High-resolution monochrome (option): 1280 x 860

Standard color (option): 640 x 480

High-resolution color (option): 1280 x 860
 Software System

Vision64 Control and Analysis Software on

Windows 7 64-bit OS
 Software Packages

Production interface; Acuity XR; Annular Analysis;

High Speed AF; Optical Analyses; Advanced Image
 XY Automation

 Manual stitching standard;

 Automated stitching, scatter and grid automation   standard with motorized XY stage
 Calibration-            Via traceable step standards
 System Footprint    450 mm (W) x 534 mm (D) x 632 mm (H)
 System Weight       60.3 kg (133 lb)

Utility and Working Principal

Optical profiling uses the wave properties of light to compare the optical path difference between a test surface and a reference surface. Inside an optical interference profiler, a light beam is split, reflecting half the beam from a test material which is passed through the focal plane of a microscope objective, and the other half of the split beam is reflected from the reference mirror. When the distance from the beam splitter to the reference mirror is the same distance as the beam splitter is from the test surface and the split beams are recombined, constructive and destructive interference occurs in the combined beam wherever the length of the light beams vary. This creates the light and dark bands known as interference fringes.

Since the reference mirror is of a known flatness – that is, it is as close to perfect flatness as possible – the optical path differences are due to height variances in the test surface.  This interference beam is focused into a digital camera, which sees the constructive interference areas as lighter and the destructive interference areas as darker. In the interference image (an "interferogram") below, each transition from light to dark represents one-half a wavelength of difference between the reference path and the test path. If the wavelength is known, it is possible to calculate height differences across a surface, in fractions of a wave. From these height differences, a surface measurement – 3D surface map, is obtained.


Sample Details

  • Metallic, coated sample, thin films
  • Dimension    10x10mm or larger
  • Preparation  No polishing is required

3D Surface contour of Electron beam welded pure niobium sample



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