Challenges In Manufacturing MEMS Inertial Measurement Units
MEMS inertial measurement units (IMUs) are currently manufactured using
hybrid integration at the system level. While co-fabrication of components has
been proposed, it has yet to produce a useful implementation of IMUs. Major
challenges include large component size, inadequate performance, device
coupling, and conflicting process and package requirements for accelerometers,
gyroscopes and timing units.

University of Michigan's Technology For Manufacturing MEMS Inertial
Measurement Units
Researchers at the University of Michigan have designed a manufacturing
technology called PAckage of Silica for Timing and Inertial Measurement or
PASTIME that overcomes the above challenges. PASTIME leverages fused
silica for the manufacture of complete and fully-integrated microsystems—
sensors, actuators, microdevices, and packaging.

PASTIME represents the first single-chip, all-inclusive timing-inertial system
fabricated completely using fused silica, a material known for its robustness
and excellent material properties. Under the PASTIME regime, sensors and
actuators can be fabricated either directly from fused silica (FS), or on top of FS
acting as a substrate and supporting material.

Applications
• MEMS inertial measurement units
• Optical sensors and devices
• Piezoelectric devices

Advantages
• Ease of manufacturing
o Entire system fabricated using fused silica (FS) or quartz
o Modular packaging
• Single or multiple FS layers in one integrated package
o Multiple navigation-grade sensors, actuators, and resonators on
every layer
o Support for heterogeneous and diverse layer materials
o Varied layer thicknesses to optimize sensor/resonator
performance
o Optimized pressure levels for different sensors
o Support for previously unavailable 3D structures
• Area efficiency: Stacked silica layers and devices
• Multidirectional thermal-vibration-shock isolation
• Stability: FS has a very-low thermal expansion coefficient
• Optical transparency: Allows FS-based optical sensors and devices
• Support for hybrid flip-chip-bonded sensors

File Number: 5196