Designing small footprint, low-cost, high-reliability packages for performance sensitive MEMS sensors

Packaging micro-electro-mechanical systems (MEMS) is still recognized as a show stopper for wider application and extensive commercialization. The challenge in MEMS package design is to deliver a robust, low cost, small footprint, high reliability package that helps to deliver flawless MEMS performance over the customer regime. These are ongoing MEMS packaging challenges. This paper outlines how freescale semiconductor has successfully met the packaging challenge for the MEMS acceleration sensor. A packaging strategy was chosen from low cost and small footprint considerations. However packaging stresses impact the performance of the transducer. Coupled packaging stress and MEMS transducer response simulation was done to identify the package related parameters that were impacting the MEMS performance. As is typically the case, the packaging fix to correct for the performance resulted in a reliability challenged package that did not meet the customer life cycle expectations. An advanced package design methodology was developed to couple simulations for package reliability prediction with package performance predictions to deliver a robust, low cost, small footprint, high reliability package that delivers flawless MEMS performance to satisfy an ever tightening customer requirement. The predictive design methodology was extensively validated with experimental results at every stage for reduced cycle time for new product introduction.