vacuum packaging

**Vacuum packaging** is the **package sealing process that encloses devices under reduced pressure to control damping, contamination, and long-term stability** - it is critical for many resonant and inertial MEMS devices. **What Is Vacuum packaging?** - **Definition**: Creation of low-pressure cavity during wafer or die-level package sealing. - **Process Elements**: Includes cavity evacuation, sealing, and leak-rate qualification. - **Performance Coupling**: Internal pressure directly affects quality factor and dynamic response. - **Supporting Features**: Often combined with getters and hermetic bond structures. **Why Vacuum packaging Matters** - **Sensor Performance**: Vacuum conditions improve resonance behavior and signal fidelity. - **Noise Reduction**: Lower gas damping can increase sensitivity in certain device classes. - **Reliability**: Controlled atmosphere protects structures from oxidation and contamination. - **Calibration Stability**: Pressure consistency reduces device-to-device variation and drift. - **Application Readiness**: Automotive and industrial sensors often require stable vacuum cavities. **How It Is Used in Practice** - **Seal Process Control**: Tune bonding parameters to capture target pressure at closure. - **Leak Screening**: Use helium and pressure-decay tests to verify cavity retention. - **Long-Term Validation**: Run aging tests to confirm vacuum stability across mission profile. Vacuum packaging is **a performance-defining package approach for sensitive MEMS devices** - vacuum integrity is essential for predictable long-term sensor behavior.