Thermo-mechanical pre-optimisation of radar sensor design by means of FEA and microDAC measurements

More and more dense packaging is one of the most important challenges in advanced electronics and micro technology, driven by requirements like low cost and high reliability. One way to meet these demands is to follow the so-called ldquochip in duromerrdquo approach, which allows an extremely dense integration and very short interconnects. Already in the very first design phase of advanced products, numerical studies by means of finite element analyses (FEA) are very efficient to check the desired properties regarding functionality as well as reliability aspects. This has been carried out with a new generation of active distance control (ADC) devices for automobiles, based on a radar principle. In order to obtain sufficiently flat modules for subsequent manufacturing steps, thermally induced deformations were measured at suitable specimens by means of the microDAC technique, developed by CWM GmbH Chemnitz and Fraunhofer IZM. Combining FE analyses and measured deformations, a methodology was developed which can be generalised and applied to many design procedures before any real parts are available. It is helpful to reduce cost and time-to-market for future products by minimising real tests and an expensive redesign.