MEMS Sensors with Selectively Adjusted Damping
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Solution Overview
Problem
Micro-electro-mechanical systems (MEMS) inertial sensors are susceptible to external forces, leading to compromised functionality and performance due to vibration sensitivity, particularly in modes like the 'hula' and 'trampoline' modes, and existing solutions either increase package size or limit pressure differences between sensors.
Innovation Solution
The integration of metallized layers on suspension structures within MEMS devices to selectively adjust damping, allowing for optimized damping of sense modes without altering the drive mode's Q-factor, enabling increased robustness and sensitivity while accommodating sensors with different bandwidth requirements within a single package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sensors with different Q-factors are integrated within a single package, then device versatility is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by depositing metallized layers selectively on specific suspension structures. Different suspension structures receive different metallization treatments (e.g., aluminum, titanium, platinum, or composite layers) to achieve different damping characteristics. This allows sensors with different Q-factors to coexist in a single package without requiring separate packages or cavities for each sensor type.
2Reliability
If vibration damping is increased for sense modes, then reliability is improved, but measurement precision deteriorates
Solution Approach 1:
The patent selectively applies metallized damping layers to specific suspension structures that support sense modes, while leaving other suspension structures untreated. This localized approach increases vibration damping for sense modes (improving reliability) without affecting the drive mode performance, thereby maintaining measurement precision.
Solution Approach 2:
The patent segments the suspension system into different parts with different damping characteristics. By applying metallized layers to only certain suspension structures and not others, the system achieves differentiated damping: high damping for vibration-prone sense modes and low damping for drive modes, resolving the contradiction between reliability and measurement precision.
3Object-affected harmful factors
If thin film damping layers are added to reduce vibration, then object-affected harmful factors are reduced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent changes the physical parameters of existing suspension structures by depositing metallized layers with controlled thickness and material composition. By adjusting parameters such as layer thickness (e.g., 10-100 nm) and material type (aluminum, titanium, platinum, or composites), the damping characteristics are tuned to reduce vibration susceptibility without fundamentally changing the device architecture or manufacturing process.
Solution Approach 2:
The patent employs composite materials by combining metallized damping layers with the base suspension structure materials. Composite configurations include aluminum-silicon nitride, titanium-silicon, or platinum-silicon combinations, which provide optimized damping properties while maintaining structural integrity and being compatible with standard MEMS fabrication processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances vibration immunity and sensitivity of MEMS sensors by selectively adjusting damping, allowing for the integration of multiple sensors with varying Q-factors in a single package, reducing unwanted motion and mechanical noise while maintaining high sensitivity and adequate bandwidth.
Implementation Method 1
The one or more metallized layers provide selectively adjusted damping of the one or more suspension structures
Data Source
AI summary
A micro-electro-mechanical systems (MEMS) device and method of fabricating the MEMS device are disclosed. The MEMS device comprises a substrate, one or more suspension structures connected to the substrate, one or more metallized layers on the one or more suspension structures, and one or more sense structures connected to the one or more suspension structures. The one or more metallized layers provide selectively adjusted damping of the one or more suspension structures.