Flip Chip Bonding of a Quartz MEMS-Based Vibrating Beam Accelerometer

Area of Science:

• MEMS technology
• Sensor fabrication
• Quartz micro-machining

Background:

• Micro-accelerometers are crucial for motion sensing.
• Traditional assembly methods can limit precision and performance.
• Quartz is a suitable material for resonant sensors due to its mechanical properties.

Purpose of the Study:

• To propose and demonstrate a novel flip chip bonding technique for micro-accelerometer assembly.
• To optimize the sensing element structure using finite element method (FEM) simulations.
• To achieve high sensitivity and quality factor (Q value) in the fabricated micro-accelerometer.

Main Methods:

• Fabrication of double-ended tuning fork (DETF) and proof mass structures using quartz wet etching on Z cut wafers.
• Finite element method (FEM) for vibration mode simulation and structural optimization.
• AuSn solder flip chip bonding for precise assembly of the DETF and proof mass.

Main Results:

• Successful assembly of a micro-accelerometer using the proposed flip chip bonding technique.
• Achieved high sensitivity of 9.55 Hz/g with the DETF resonator.
• Obtained a high Q value of 5000 in air for the micro-accelerometer.

Conclusions:

• The flip chip bonding technique offers a precise and effective method for assembling micro-accelerometers.
• The fabricated quartz micro-accelerometer demonstrates high performance characteristics.
• This method has potential for advancing MEMS accelerometer technology.