Implant MEMS Pressure Sensor Venting for Drift-Stable Readings

The continuous bond line is segmented into discontinuous bond lines with gaps or discontinuities. This segmentation reduces the total bond line length, thereby reducing cumulative stress relaxation while maintaining adequate mechanical strength through optimized gap placement and size. The discontinuous bond lines prevent stress from propagating continuously around the perimeter, reducing signal drift over time.

The bond line geometry parameters (gap size, discontinuity placement, bond line thickness) are optimized to compensate for thermal expansion effects. By carefully controlling these parameters, the design allows the encapsulated components to expand and contract with temperature changes while maintaining stable capacitive gap dimensions, thereby reducing temperature-induced frequency offsets.

The problematic gas composition that slowly changes over time is extracted or vented from the capacitive gap through the discontinuous bond lines. The gaps allow exchange with the external environment or housing cavity, preventing accumulation of composition-changing gases while maintaining adequate sealing for measurement stability. This extraction approach prevents long-term drift caused by composition changes.

Instead of uniformly thinning the entire bond line, the approach segments the bond line into bonded regions and gap regions. The bonded portions maintain adequate thickness for strong adhesion, while the gaps provide stress relief. This segmentation allows manufacturing processes to work with thicker, more controllable bond material while achieving stress reduction through the discontinuous pattern rather than through thinning.