Design and Fabrication of a PCB MEMS Module with Integrated Switches and Sensor Suite

We demonstrate the feasibility of integrating Kapton-based MEMS capacitive switches and a sensor suite onto a printed circuit board with minimal impact to existing manufacturing processes. Copper-cladded Kapton laminates were bonded onto rigid PCB substrates with a BCB film spacer. The Kapton was patterned using reactive ion etching to produce MEMS structures such as suspended membranes and flexures. Atomic layer deposited alumina coatings were applied as dielectric layers for the capacitive switches and tilt sensors/accelerometers. The copper cladding was also patterned by etching to function as electrical leads, resistors, and capacitive electrodes. In this way, MEMS switches, tilt/acceleration sensors, temperature sensors, humidity sensors, and vacuum/pressure sensors, were all fabricated monolithically onto a PCB in a single module in the same fabrication process. We describe the fabrication process and demonstrate the functionality of the various sensors and switches in the module.