Fast focusing axis from ITK makes 3D scanning applications more powerful

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Photo: ITK

In sectors such as the semiconductor industry and life sciences, there is now a wide range of different imaging techniques that can detect and display structures with sub-micrometre dimensions.

Modern microscopy techniques – from optical confocal to magnetic micro- and nanoscopy – enable the identification or diagnosis of the smallest defects or biological bodies. The common denominator in these techniques is that optical assemblies or sensors in the vertical direction compensate the Z-profile of the object being examined in a highly dynamic and precise manner during the scanning movement to ensure a sharp image. This makes Z-tracking more effective during the scanning process.

To meet the increasing requirements such as faster, more accurate, more precise and more efficient, ITK has developed a new High Speed Autofocus (HiSA) axis unit, consisting of an ironless linear direct drive on a voice coil basis, an integrated magneto-resistive position measuring system, precision guides and weight compensation to compensate for the mass of the moving load.

Different lightweight construction principles were used to achieve a significant weight reduction (minus 45%) compared to the previous model. The combination of direct drive and position measuring system enables a repeat accuracy of 100nm and a positioning accuracy of < 500nm. The passive weight compensation simplifies position control and leads to a noticeable reduction in power loss when the load has to be held in a specific vertical position.

A typical application for the new HiSA axis unit concerns the fast vertical axis of the PT-15 3D gantry positioning system from ITK, which is used in the semiconductor industry, among others. Sensors or lenses can be positioned quickly and precisely over the surface of silicon wafers. The HiSA axis unit contributes to a significant increase in precision and productivity. It is particularly advantageous that the linear direct drive is wear-free and has no play.

Pitch errors or friction – which occur with spindle-driven axes – are virtually eliminated. The low power loss leads to minimal thermal drift and therefore also to excellent focus stability.

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Jim Cornall is editor of Deeptech Digest and publisher at Ayr Coastal Media. He is an award-winning writer, editor, photographer, broadcaster, designer and author. Contact Jim here.