MEMS Pressure Sensor Drift Due to Hygroscopic Swelling

Application ID: 21021

Modern integrated circuits are available as plastic encapsulated microcircuits (PEM). These devices are molded out of polymeric materials and epoxy resins in order to protect the internal semiconductors. Unfortunately, polymeric mold compounds absorb moisture when exposed to a humid environment, thus swelling and causing undesired strains, which can be as high as thermal strains.

This application studies the moisture diffusion across the mold compound that protects a MEMS pressure sensor. The hygroscopic swelling induced by the moisture diffusion induces a drift in the measured characteristics of the sensor.

This model example illustrates applications of this type that would nominally be built using the following products: