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Wafer Topology Measurement System

The Solar Cell Wafer Topology Measurement System is a complete system for geometry, two-sided sawmarks and thickness measurements. Wafers are measured with low noise, high sensitivity, high repeatability and high resolution.

 

Unique shadow measurement techniques, cancelling the effects of the crystal pattern combined with Scorpion Vision Software® are the key elements of this world class system. The combined sawmarks and thickness measurement system measures with a resolution of 1 micrometer. The system is a standard instrument and can easily interface to any production line system.

 

Wafer sawmarks

Sawmarks are measured using a patent pending and unique shadow measurement technique, cancelling the effects of the crystal pattern. Advanced image processing algorithms work on the shadow images to identify sawmarks with high accuracy. The operator can verify how the sawmarks develop over the wafer. Large sawmarks will often have a large gradient towards the edge of the wafer.

 

Wafer thickness

The system measures both the mean thickness and the total thickness variation (TTV). The wafer thickness is measured using an angled lighting and shadowing technique. The shadow position is measured simultaneously on both sides of the wafer. The thickness is calculated from the shadow positions both at the wafer centre and 10 mm from the edges. Slightly warped wafers are handled.

 

Wafer geometry

The wafer dimension and corner shapes are measured. The wafer dimension is determined based on these measurements: The distance between parallel edges measured in two places Length and angle of each edge Corner measurements The resolution is better than 0,01 mm on all length measurements.

 

Complete wafer inspection system  

The high precision, reliable and compact topology solution is built on the Scorpion Vision Software platform with 2D and 3D machine vision capabilities. The interface to the automation and data collection system is highly flexible. The system includes off-the-shelf world class hardware components such as area- and line scan camera technology.  

 

Measurement Specification    

Geometry

  • Corner shape – length and angle of all four corner grindings
  • Wafer dimensions
  • Length, width, diagonals, squareness

Thickness    

  • Thickness is measured on the middle of the wafer and 10 mm from the edges.
  • 40 µm pixel size
  • Resolution thickness and TTV: 1 µm
  • Range: 50 to 250 µm

Sawmarks

  • Sawmarks are measured with a profile resolution of 20, 40 or 70 µm. This means that narrow marks with a width of 100 µm are detected.
  • One sided or two sided measurement
  • The maximum sawmarks detected with a 1 mm window is measured from 4 - 100 µm with 1 µm repeatability. 

More details in pdf.

 

 

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Tordivel Solar AS | Storgata 20 N-0184 Oslo Norway | Phone +47 2315 8700 | Fax +47 2315 8701

FNR: NO 992 641 908 MVA | office@tordivelsolar.com | www.tordivelsolar.com