TEMPERATURE MEASUREMENT

Component Inpsection

• Infrared cameras with microscope optics as well as high performance infrared thermometers allow for the detection of smallest measurement areas or spots (28 µm). By this, single components and junctions can be checked for heating spots or heat impact among each other.

Power Loss Generates Heat

• The ever-increasing integration density, however, means that the amount of heat resulting from power loss in the components increases all the time. Another factor here is continual miniaturization, which can impede efficient heat dissipation. Even applications which carry relatively large currents are becoming more and more common – in drive technology for example – thanks to the use of power electronics. The lifespan of semiconductor elements is hugely dependent on temperature. An increase in temperature of 10 °C will cause a 50% reduction in lifespan. This means that developers of electronic assemblies are faced with the challenge of allowing for the thermal behaviour of circuit boards and assemblies.

Recording Temperature

• The temperatures of semiconductors, printed circuit boards or entire assemblies are ideally measured with the help of infrared technology. The measuring procedure is quick, precise and non-contact – a consideration of particular importance in electronics manufacturing. When measuring, checks should be made to see where exactly a circuit board is showing which temperatures. The causes for excessive temperatures can be manifold: defective components, incorrectly dimensioned circuit paths or poorly soldered joints. In order to properly record the temperatures of very small components and structures on a circuit board, an infrared camera with a suitably high resolution is necessary. With this you can, for example, identify exactly which component on a circuit board is displaying excessive temperatures.

Process Temperature

• 30 °C to 120 °C

Design Validation

• Electronic assemblies have to get smaller, more powerful as well as more cost effective. Design – both the arrangement and the application of the elements – is a key factor. Infrared measurement technology ensures an efficient heat management. The VGA thermal imager optris PI 640 is perfectly suited for these tasks.

Non-Contact Temperature Measurement during Development, Production and Incoming Inspection

Thermal Model Calculations

• Infrared cameras are used in various phases of electronics development. Often, temperatures on a printed circuit board are simulated in advance using thermal model calculations. When measuring prototypes these model calculations can then be verified. Should any discrepancies arise, the data gathered during measurement can in turn be included in the simulations to improve the models. When measuring prototypes, components which consume an excessive amount of energy can be identified. This allows errors in the circuit design to be spotted at an early stage. The mutual interference of components on the circuit board can also be detected.

Process Temperature

• 30 °C to 120 °C

Quality Control

• In production, assemblies from external suppliers are often used. To carry out incoming quality control of these assemblies, infrared measurement technology is also used here. This control can be carried out on all items, or by means of random sampling. Infrared cameras are also employed in the final inspection as part of the quality assurance of finished assemblies or circuit boards. This allows faulty components or assemblies, for example, to be identified during burn-in tests.

String Soldering

• For the production of solar modules the temperature of wafers is captured during the string soldering process. This assures a reliable and efficient assembling process. Temperature measurement takes place on the silicium surface which is connected to the braze point. That’s how the quality of the homogeneity of the soldering is measured.

Quality Control of Solar Cell Modules

• Infrared cameras are essential instruments for the quality control of solar cells. One possibility of testing is the periodical modulated exposition of the solar cells to light (Illuminated Lock-In Thermography). The separation of charge within the solar cell leads to leakage current at defective parts and thus to local hot spots. The hot spots can be detected by the infrared camera.