Thin-film measurement questions and answers

Practically any translucent coating. If a coating is opaque in the visible range, the near-infrared range can be used instead. MProbe measures thousands of different applications, and new ones are discovered constantly. There are only a few coating types we can't measure: pigmented paint, thick metal films (> 50 nm), and graphite - though amorphous or diamond-like carbon is no problem - as well as paper and textile/fabric.

It depends on spectrometer resolution and wavelength range, so it differs for each MProbe model, and it also depends on the sample's optical properties (refractive index and absorption). Several MProbe models can be combined to extend the range. The total range across the family is 1 nm to ~2 mm.

MProbe uses an optical method, so measurable metal thickness is limited to roughly < 50 nm. Thicker metal films become opaque and cannot be measured.

A typical measurement is < 100 ms, including both data acquisition and analysis. Measurement conditions and the filmstack can be optimized for faster results when needed.

There are many ways to integrate MProbe, or part of it, with a third-party system - both software and hardware integrate easily. The software supports remote control of measurement through an optional TCP server (Modbus-based), and several OEM hardware packages are available depending on requirements. Contact us to discuss yours.

Yes - MProbe is used in many inline measurements today, and we customize the system for each new application. Depending on requirements there's a static-position option (1 to 5 probes) and a scanner-mounted option. Contact us to discuss your setup.

Often, yes. University and R&D customers sometimes already have a spectrometer and other components and just need suitable software. TFCompanion™ works with several commercial off-the-shelf spectrometers, including Ocean Optics and Avantes USB spectrometers, with different installers depending on the spectrometer. Let us know your model and application requirements.

Our MProbe 40 (MSP) system uses an inspection-grade reflectance microscope with long-working-distance objectives. Practically any microscope can be integrated, but be careful about the wavelength range its optics support. The easiest path is our microscope adapter, which connects to the C-flange of the microscope's camera port and includes a beamsplitter and a 2 MP camera.

The MProbe system has both USB 2.0 and 1 GB LAN interfaces; either can be used. USB is convenient (direct connection, no router) but is limited to short cable lengths (< 10 ft / 3 m); an interrupted connection usually can't be restored without a manual restart, and moving or touching the cable can cause a disconnect. LAN avoids these issues - it works over long distances, and an interrupted connection can be restored quickly without restarting the system.

Low or no disconnects is a key inline requirement. MProbe has firmware and software support to restore a connection without a restart: at the firmware level the spectrometer uses a watchdog that monitors activity and resets the firmware on a problem, and at the software level the driver automatically restores a lost connection. As a result, MProbe can run continuously for a long time.

The system uses 24 V DC to power the spectrometer electronics and light source. Power requirements depend on the system and range from 20 W to 120 W. Each system includes a 24 V DC adapter rated for long-term stable operation; if a 24 V DC line is available, it can be used instead of the adapter.

Yes. There's an option for analog output of up to 4 thicknesses (4 layers) - typically 0–20 mA, with 0–5 V also possible - and TCP server software with an interface suitable for PLC integration.

Spot size depends on the fiber core and lens magnification. The standard fiber core is 0.4 mm and the standard lens magnification is 1× (from the MProbe 20 system), giving a spot typically < 1 mm. MProbe 40 offers different objectives and can go down to 2 µm. There's a trade-off: as the spot shrinks, less light is collected, so integration time increases.

Some cases obviously need a small spot - measuring small areas (a patterned wafer) or a coating on a wire or other highly curved surface. Otherwise it isn't always possible to know whether, and how small, a small spot is needed without prior experience or experimentation. The general rule: the measurement area should be flat and uniform in thickness within the spot. For example, coating on an unpolished metal surface frequently requires a small spot.