Crytur

Quality Is Essential in the Manufacturing of Detectors for Electron Microscopes

The company Crytur deals with the design, production and delivery of integrated optoelectronic and optomechanical assemblies. The basic parts of these products are synthetic crystals that the company produces itself. Because the products supplied by Crytur are very demanding in terms of dimensional and shape accuracy, the company is equipped with top-quality measuring machines and gauges from Mitutoyo.

Company Crytur is based in Turnov, Czech Republic, in the region called the Bohemian Paradise. In addition to the beautiful nature and historical monuments, this place is also known as a deposit of semi-precious stones. Agates, jaspers, amethysts or rock crystals are the remnants of Permian-Carboniferous volcanic activity.

The experts at Crytur are trying to mimic natural processes and produce synthetic crystals for technical applications. Synthetic garnets and perovskites are used as active media in lasers or for X-ray imaging and electron microscopy. Lead-tungstate crystals are scintillation crystals used in high energy physics experiments. At CERN, the European Centre for Nuclear Research, this type of crystals made a major contribution, for example, in proving the discovery of a new elementary particle – the Higgs boson – in 2012.

Although Crytur did not produce lead-tungstate crystals for CERN for this particular project, all new key experiments at CERN are currently built on thousands of these crystals from Turnov.

The company also produces sapphire profiles, which are used e.g. as protective thermocouple housings for the glass industry or petrochemistry. The range also includes optical elements with thin layers: the functional layers are applied to the optical surfaces by vacuum evaporation.

From components to complete assemblies

However, the largest part of the production currently consists of detection units for electron microscopy. Detectors, especially those for back-reflected electrons and secondary electrons, are one of the key elements of the microscope. Without them, it is impossible to display extreme detail in the nanometer range.

"Crytur cooperates with Czech and foreign manufacturers of electron microscopes," says Jan Bitman, marketing manager of Crytur. "The high-end detectors manufactured at Crytur are not only supplied to laboratory instruments but are also used extensively in industrial electron microscopes for quality control in microchip production. It is no exaggeration to say that the high-end detection units manufactured for customers in the semiconductor industry are one of the few direct Czech footprints in the production of microchips as such," he adds.

New requirements for quality control

The expansion of Crytur's product range to include complex optoelectronic and optomechanical assemblies has brought new requirements in the field of quality control.

"The manufactured parts are very precise and have to fit together very precisely. When we talk about very precise dimensions and tolerances, we are talking about tens of micrometers, and in shape and position tolerances we are talking about sub-micron values," says Gabriela Tausig, Head of Quality Management at Crytur.

The need to accurately measure each part and check correct assembly has led to Crytur buying an impressive fleet of measuring machines and equipment from Mitutoyo.

Coordinate Measuring Machines

Coordinate measuring machines are the basis of production quality control. First, these are STRATO-Apex coordinate measuring machines in two sizes, STRATO-Apex 574 and STRATO-Apex 9106. They are highend machines of bridge-type design with air bearings on all axes and high-precision measuring rulers with low temperature expansion. The smaller STRATO-Apex 574 has a travel of 500 × 700 × 400 mm, the larger STRATO-Apex 9106 can measure parts up to 900 × 1,000 × 600 mm and both have a resolution of 0.02 μm.

The company has two of each of these machines in two measuring laboratories. Other equipment includes CNC coordinate measuring machines CRYSTA-Apex S 574 and CRYSTA-Apex V 544 designed for measuring small and medium-sized parts. The fleet is completed by two CRYSTA-Plus M 443 machines – compact manual measuring machines for smaller parts with simple operation.

Other measuring technology

Mitutoyo ROUNDTEST RA-2200 CNC and ROUNDTEST RA-1600 are also among the top measuring instruments. These devices can measure circularity or concentricity deviations very accurately.

The first one is equipped with a function for automatic centering of the measured part, the second one is manually centered by means of the DAT (Digimatic Adjustment Table) guidance function. Both approaches have their advantages: automatic centering is faster, on the other side, even very complex measuring tasks can be handled by manually centering.

Some polished surfaces cannot be measured by mechanical probes as this would damage them. That is why Crytur is equipped with two Quick Vision Active QVT1-L404 visual measuring instruments. The instruments have motorized zoom, multi-source illumination and powerful data analysis software. The measuring range is 400 × 400 × 200 mm and the resolution is 0.1 μm. A simpler visual instrument for smaller flat parts is the Quick Scope QS-250 Z (200 × 250 × 100 mm) - Crytur is equipped with two of these instruments.

The company has five TM-1005B measuring microscopes to measure the dimensions, angles and shapes of small parts. These are monocular microscopes with two objectives and an LED illumination.

Crytur also has other measuring equipment and gauges from Mitutoyo: calipers, micrometers, etc. All of them have digital output. "There may be cheaper gauges on the market than products by Mitutoyo, but we need to be sure that they will measure accurately and reliably for their entire lifetime," says Gabriela Tausig about the reason for choosing Mitutoyo.

Quick Vision Active QVT1-L404 visual measuring device

TM-1005B measuring microscope

Software for measuring machines and equipment

Crytur is not engaged in mass production. Individual and small production batches are usually only in tens of units. Gabriela Tausig therefore highly appreciates the software that is part of the measuring machines and equipment: "MCOSMOS software in tandem with the off-line programming environment MiCAT Planner allows us to conveniently and quickly prepare measurement procedures directly from the part, model or drawing. Compatibility between devices and device types is also an important aspect. In addition, we have the MeasurLink software for the statistical evaluation of measurement results (SPC). Its advantage is that we can input data from CMMs, roundtests or any other measuring equipment and evaluate the stability and repeatability of the complete process." Statistical Process Control (SPC) allows real-time evaluation of measurement data and monitoring of trends in manufacturing processes. It is possible to react in time to deteriorating parameters, thereby reducing scrap, and increasing production efficiency.

Mitutoyo is a guarantee of quality also for end customers

Crytur appreciates the very good price/quality ratio of Mitutoyo measuring machines and equipment. This was the first reason why the company decided to use this brand. But that's not all. "We have a great relationship and whenever we are dealing with a job and we don't know what to do, Mitutoyo's engineers are there to help. They are helpful in terms of service, calibrations and in dealing with any faults if it occurs. Their response time is very short," says Gabriela Tausig, adding: "What is also important: the Mitutoyo brand is a guarantee of quality even for our demanding customers."

"If you want to play a key role in the market, you need to use the best of best measurement technology available. Take the production of silicon wafers in the semiconductor industry as an example. Finding bug on it is like looking for ant in a big city. And you have about ten seconds to do it. If you must achieve such accuracy in detection, it is impossible to underestimate anything in the production of detectors," comments Jan Bitman in conclusion.