Sioux develops, builds and integrates optical metrology modules

We distinguish ourselves because we are a valuable technology partner for companies, specifically where the combination of illumination, projection, light path, image acquisition and image processing is essential for e.g. accurate positioning. This helps clients to perform better in their international markets.

Where the performance requirements for precise positioning by high-tech modules are increasingly being advanced (e.g. to lower critical dimensions and repeatability), mechanical solutions are often insufficient or too expensive. Combining high-quality optical components with smart software and mathware for calibration and process measurements is crucial for the latest micro or nano meters accuracy of e.g. printing and positioning systems. Sioux has unique knowledge and experience in this area.


Sioux developed the complete metrology module for the backend stepper of Liteq. The system includes wafer (pre) alignment, reticle (pre) alignment, level sensor and focus sensor. For the alignment sensors, markers are used, in combination with image acquisition and image processing. For the level sensor, an LED light path is used, in combination with triangulation methods. For the focus sensor, a light diode with 10 KHz is sampled in the focus field to determine the optimum. Through this optical metrology, a critical dimension of < 2 micrometres and an overlay of < 500 nanometres is realized.

Knowledge domains

  • Optical sensors for:
    • Inspection of substrates
    • Distance, position and orientation measurements
  • Calibration (metrology) of:
    • Straightness or misalignment of axes in motion
    • Systematic deviations
  • Inspection, process monitoring and position measurement of:
    • Wafers in the semiconductor industry
    • PCB substrates in the printing industry
    • Web position in the printing industry
    • Glass slides in the medical industry
    • Cryogenic Trays in the pharmaceutical industry

Technological areas

  • Vision lenses
  • Lighting for optimal contrast
  • Microscopy, fluorescence
  • Lens design with Zemax
  • Optical sensors for measuring distance and position
  • Laser interferometry

Sioux is the specialist in the application of optical sources, light paths, sensors and corresponding correction algorithms in optical metrology modules. From the very first stages of development of new machines, we focus on the required accuracy. We rely on our vast knowledge of mechanics, electronics, calibration and process measurements. Sioux also knows what is available for sale on standard measuring systems and what is needed to process sensor data ultra-fast. For example, we can maximise the dynamics of movements by using fast computing units and advanced control technical mathware. If necessary, Sioux will develop a new sensor and the corresponding signal processing unit itself.

Sioux is a global player that develops innovative solutions for very fast indexed positioning of flexible substrates
‘Sioux is a global player that develops innovative solutions for very fast indexed positioning of flexible substrates’

Joep Stokkermans, R&D Manager ITEC, and part of Nexperia (formerly NXP).

Speed of innovation

Speed of innovation is key to the market success of companies. Sioux wants to offer its customers a flying start in creating new high-tech equipment. That's why we have developed a number of highly tech in-house solutions.

  • PCB inspection up to 24" by using a line scan camera system with 2.8 µm interpolated resolution and associated real-time image processing.
  • Wafer inspection by a multi-colour corrected vision lens with a resolution of 5 µm. The lens is tele centric to minimise magnification errors. The coaxial lighting has 3 LED colours blue 457 nm, green 525 nm and red 622 nm and accepts a substrate tilt of ± 2° without loss of image quality.
  • Particle detection > 0.2 µm on flat substrates.

In this way, we offer our clients - whether they are modules or complete high-tech systems - accelerate in their business cases, in quality, cost efficiency and their time-to-market.



Sioux developed a completely new medical diagnostic product for Orthoproof: an automated system for workflow, scanning, modelling, analysis and printing of 3D denture models. With a grid projection of a laser, a 3D image of the human teeth is made using image analysis and triangulation techniques with an accuracy of about ten µm. The scanner knows where it is by using accelerometers and precise setting algorithms


Hard disk drives are very sensitive to dust particles that can damage the surface during production and use. During production - in addition to a clean operation - fast, thorough and cost-efficient intermediate dust inspection is crucial to be competitive. Sioux developed a particle scanner for Seagate that can detect dust particles from 0.35 µm and higher throughputs. Using this customised optical tool, the size and position of particles found are passed on to enable cleaning. Commercially available particle scanners can sometimes detect smaller particles, but are much more expensive and slower.