Automated High-Throughput Hermetic Failure Monitoring System for Millimeter-Sized Wireless Implantable Medical Devices

This paper presents an automated high-throughput hermetic failure monitoring system for millimeter-sized wireless implantable biomedical devices (IMDs). To protect the electronics from the harsh body environment as well as the body from potential toxic chemicals in the package of the IMDs, a lifetime estimation for the hermetic package of the IMDs is essential as a key part of IMD design and development. However, traditional leak tests are not suitable for the small form factor of mm-sized IMDs. The presented automated hermetic failure monitoring system can enable lifetime estimations for multiple mm-sized wireless IMDs at low cost and in a user-friendly setup. Thereby, liquid/vapor ingression into the IMD package is monitored by registering the phase-dip frequency shift of a passive LC tank. Exposing 1.3×1.3 mm
²
sized IMDs to an accelerated testing environment (1 atm, 100% RH, and 80 °C), a 186 kHz frequency resolution and a signal to noise ratio (SNR = 10log(△φ
_dip
/φ
_noise
)) of 21.8 ± 0.8 dB were achieved within an operating frequency range of 50-200 MHz and at 0.4 mm interrogation distance.