03/10/2020

CWL - Chromatic white light sensor for fast and high-precision metrology

Configurable for a multitude of measuring tasks and surfaces

In the investigation of flat, extended structures, a number of questions have to be answered. An important parameter is the surface roughness of the samples to be measured, which is in the nm or even sub-nm range. The second important property of the surface is the shape. The surface to be examined should not be curved. Smallest deviations from the ideal flat shape must be detected.

Most of the surface measurement systems available on the market are not capable of measuring both roughness and flatness. For example, systems for measuring flatness or bow can only record the surface with low lateral resolution. However, high-resolution profiles across the entire extended surface for the detection and measurement of waviness with small period lengths cannot be recorded with these systems, and also the surface roughness cannot be measured with them.

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FRT solves this measurement task with the fast optical distance sensor CWL with extremely high z resolution and a high-precision x,y table.  This system can record the complete surface to determine flatness and waviness. In addition, local high-resolution topography measurements or profiles with high resolution across the entire surface can be acquired quickly.

The CWL works on the principle of chromatic distance measurement. White light is focused on the surface by a measuring head with a focal length that is strongly dependent on the wavelength. The spectrum of the light reflected from the surface shows a peak from which the distance to the sample surface is determined. The non-destructive method of the CWL works equally reliably on highly and poorly reflective surfaces.

The CWL can be configured to suit your specific application. Standard and special measuring heads with different measuring ranges are available. With different measuring heads, height measuring ranges from 300 μm to 10 mm can be acquired without moving the sensor or measuring object in height. The maximum height resolution is 3 nm. A lateral resolution of 1-2 μm is achieved.

New now! CWL DS - Chromatic white light sensor with dual spectrometer

The CWL DS is equipped with two independent measurement channels, which allow simultaneous measurements to be acquired at the full measurement rate of 10 kHz per channel. The exposure is done by an electronically controlled shutter. The embedded processor of the sensor records the respective data, synchronizes them and directly outputs corresponding thickness or step height values. This makes the CWL DS the ideal sensor for double-sided thickness measurement of non-transparent or very thick materials that cannot be measured with only one sensor head. In addition, the CWL DS is a cost effective and space saving sensor as it replaces two single sensor systems. With a rotary button and the function keys on the front of the sensor, the display can be used to configure basic sensor parameters in setup mode and to show the spectrum in data mode. Due to its light intensity and high measuring rate, the sensor is suitable for a variety of tasks in production control and R&D. Up to 10 different measuring heads can be calibrated to one electronics and used alternately as required.

New now! CWL HF - Chromatic-confocal and interferometric measurement technology in one single sensor

The CWL HF is perfectly suited for the non-contact measurement of topography and layer thickness. It offers an extremely high frequency of 20 kHz. The high dynamic range and the excellent signal-to-noise ratio ensure the best measurement results even on surfaces with different reflective properties. The sensor can be switched from chromatic-confocal to interferometric measurement technology, so interferometric film thickness sensors can be used. As an option, it is possible to use a xenon plasma lamp instead of the internal LED. With its higher light intensity, it offers the possibility to perform reliable measurements even on weakly reflecting samples. Up to 16 different measuring heads can be calibrated to one electronic unit and used alternately as required.

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We are sure to have a solution for your specific task. Please do not hesitate to contact us if you have any questions. Our experts will be glad to take care of your request and work out individual solutions for you.

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