Silicon MEMS Torque Sensor High-Temperature Bonding
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Solution Overview
Problem
Conventional torque sensors using quartz and polymers are limited by their temperature and pressure tolerance, leading to vulnerabilities such as sensitivity to vibration, creep, and temperature extremes, which affect accuracy and lifespan.
Innovation Solution
The development of a torque sensor using a silicon substrate with microelectromechanical systems (MEMS) and high temperature bonding surfaces, allowing direct connection to metal objects via high temperature processes like soldering, metalizing, or brazing without polymer adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional quartz and polymer packaging is used for torque sensors, then the sensors can be easily manufactured and assembled, but they exhibit sensitivity to vibration, creep, and temperature extremes which reduces reliability
Solution Approach 1:
The patent removes the polymer adhesive layer from the sensor structure, extracting the source of vibration sensitivity and thermal expansion issues. By eliminating this compliant layer, the sensor achieves direct bonding between the diaphragm and substrate, preventing relative motion that causes vibration sensitivity while maintaining structural integrity
Solution Approach 2:
The patent merges the diaphragm and substrate into a single rigidly bonded unit through direct bonding techniques. This consolidation eliminates the interface between separate components that could allow relative motion, thereby reducing vibration sensitivity and creep while maintaining manufacturing feasibility
2Temperature
If conventional polymer adhesives are used to bond the sensor to the shaft, then assembly is simplified, but the sensor cannot withstand high temperatures which limits operational range
Solution Approach 1:
The patent changes the bonding parameters by transitioning from low-temperature polymer adhesive bonding to high-temperature direct bonding methods. This parameter change enables the sensor to withstand temperatures exceeding 200°C while maintaining bond integrity, thereby expanding the operational temperature range without significantly complicating the manufacturing process
3Reliability
If conventional AQP packaging with inert gas is used, then the sensor is protected from environmental conditions, but the structure adds complexity and reduces pressure tolerance
Solution Approach 1:
The patent extracts and eliminates the inert gas filling requirement from the sensor packaging. By creating a hermetically sealed structure through direct bonding, the sensor achieves environmental protection without requiring additional inert gas containment features, thereby reducing packaging complexity
Solution Approach 2:
The patent merges the protective packaging function into the structural bonding interface itself. The direct bond between diaphragm and substrate creates a hermetic seal that provides environmental protection as an integrated feature rather than a separate packaging layer, reducing overall device complexity
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 solution enhances the sensor's ability to withstand high temperatures and pressures, improving durability and accuracy while reducing drift and extending the sensor's operational range.
Implementation Method 1
detects a torque associated with a metal object subject to said torque
Implementation Method 2
directly connecting the sensing element to the metal object via a high temperature connecting processes comprising at least one of soldering, metalizing and/or brazing
Implementation Method 3
directly connecting the sensing element to the metal object via a high temperature connecting processes comprising at least one of soldering, metalizing and/or brazing
Implementation Method 4
directly connecting the sensing element to the metal object via a high temperature connecting processes comprising at least one of soldering, metalizing and/or brazing
Data Source
AI summary
An apparatus includes a first acoustic sensing resonator formed from a silicon substrate and has a first microelectromechanical system. The apparatus also includes a second acoustic sensing resonator formed from the silicon substrate and has a second microelectromechanical system. The second acoustic sensing resonator is arranged on the silicon substrate at a ninety degree (90°) angle with respect to the first acoustic sensing resonator and together the first acoustic sensing resonator and second acoustic sensing resonator form a torque sensor. A high temperature bonding surface is connected to the torque sensor for directly connecting the torque sensor to a metal object.