Reliability of Mechatronic Integrated Devices Regarding Failure Mechanisms

Some of the most important quality assets of Laser Direct Structured Molded Interconnect Devices (LDS-MID) are their efficiency and reliability. In order to identify the production parameters and materials, which yield devices with superior performance, the following studies were conducted. Initially, a Design of Experiments (DoE) allowed making a qualitative and quantitative statement about conductor track defects and their causes as well as about the efficiency due to the electrical conductivity of the tracks. These results were used to suggest certain combinations of substrate material and metal layer to improve the production quality of MIDs. Such findings guide the path towards high-performance LDS-MIDs, which can be operated under harsh conditions. Along this line, specimens of 16 different factor-combinations were subjected to a temperature shock test, whereby the resistance value of the conductor tracks could be continuously measured, using a four-wire measurement. The latter allowed a precise detection of conductor cracks or solder joint failures. It appeared that most of the chosen factor-combinations showed an almost constant electrical resistance during the temperature shock tests. However, the type of thermoplastic substrate material, as well as the heat input by the soldering process, could be identified as the factors with the most significant influence on reliability and electrical conductivity.