Testing the quality of semiconductors and solar technology components

Develop and test haptic displays

With the success of smartphones, touchscreen technology has become mainstream. Now, innovative user interface concepts use haptic or tactile feedback to give touchscreens a unique feel. Such vibrations or force feedback can make operation significantly easier and intuitive by, for instance, letting the user know through touch which virtual button is under their finger or whether it was successfully activated.

Laser vibrometers are vital to the continuing research, development and quality control of haptic feedback devices. 3D motion data precisely describes the in-plane and out-of-plane vector components for a full characterization and visualization of the haptic signature. In production testing, vibrometers from Polytec assure the desired feel with laser precision. 

Assessing the quality of thick-wire bonds

Thick-wire aluminum bonds, which are widely used in the automotive industry to bond power semiconductors, need to be extremely reliable. Laser vibrometers allow you to examine the bond process in situ and are therefore critical in helping you to clarify any quality defects.

Microelectronic assemblies – where the transmission of high output levels and currents is paramount (for example power modules in the automotive industry,) – are widely processed for electric bonding purposes using so-called thick-wire bonds. The electrical contacts are made using the ultrasonic friction welding process with aluminum wires with diameters ranging from 100 to 600 μm. Resonation of the bond pads, which could well lead to a lower-quality bond connection with questionable long-term reliability, is undesirable in this regard.

Fiber-optic vibrometry is a great way of both analyzing the pads’ vibrations with maximum precision and assessing the bond quality during the bond process. Laser vibrometry combines the advantages offered by a non-contact measurement solution that doesn’t influence the sample’s vibration behavior with the benefits of a sufficiently high level of temporal and spatial resolution.

Documents

Article testing power and microelectronic interconnects

Contactlessly characterizing solar modules

Throughout their service life, solar cells are exposed to an extremely wide range of weather conditions that not only cause thermal stresses, but varying dynamic stresses too. This is precisely why developers have a major goal: namely, to deliver the greatest possible level of stability and the longest possible operating time by means of design optimization.

Material modeling and simulations help you to illustrate stress scenarios and processes for a photovoltaic module’s materials and components in a model – and, based on this, to develop and improve them in an appropriate way. You can predict both the service life and the mechanical properties for a newly developed material with a very high level of accuracy by combining various simulation methods with experimental investigations.

To get the material and structural parameters needed to do exactly that – take stiffness or damping, for example – all you have to do is measure the solar module’s dynamic properties. Scanning vibrometry, which allows you to easily determine resonance frequencies and deflection shapes, is ideally suited for this precise purpose.

Documents

Article measuring the dynamic response of solar panels

Checking the reliability of electronic and mechatronic systems

When it comes to traffic safety and competitiveness, the reliability of electronic components is a key issue in the automotive and aviation industries. Scanning vibrometry has proven to be a key measurement method for mechanical tests in this regard, so users can characterize the dynamic behaviour of both printed circuit boards and mechatronic systems. Accelerometers cannot be usefully applied to small structures. Laser measurements, however, enable performance of precise modal analyses across a wide frequency range from just a few Hz to 50 kHz. When used in conjunction with FEM and continuous tests, laser measurements provide an efficient way of optimizing the printed circuit board design and layout with a view to avoiding undesirable vibration stresses that can shorten the service life.

But that’s not all. Non-contact vibration measurement with laser vibrometers is helpful even for larger power electronic systems, such as converter modules for high-voltage direct current transmission which are used, for example, in offshore wind farms.. Their converter function can cause the converter structure to mechanically vibrate in an undesirable way, potentially overstressing it. You can make specific design improvements by using 3D scanning vibrometry to determine the natural frequencies and deflection shapes, and then you can practically check whether your improvements have been successful by repeating the vibration tests.

Documents

Article vibration test of converter modules for high voltage direct current transmission