Wafer-Bonded Force Sensor Package for Precise Wear-Free Sensing
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Solution Overview
Problem
Existing force sensors face challenges in achieving precise measurements, require robust connections to withstand environmental influences, and need wear-free mechanical contacts while ensuring overload protection.
Innovation Solution
A force sensor package is designed with a substrate and actuator bonded using wafer bonding techniques, incorporating piezo-resistive elements and capacitive sensors, and featuring overtravel stops for overload protection, with actuators permanently bonded to the substrate to ensure precise force transmission and environmental sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional mechanical connections are used between transducer element and force sensor unit, then assembly is simple, but measurement precision deteriorates due to alignment errors and mechanical wear
Solution Approach 1:
The patent replaces traditional mechanical connections (screws, clips, adhesives) with wafer bonding technology, which uses direct wafer-to-wafer bonding at the semiconductor level. This eliminates mechanical alignment errors and wear while achieving precise, permanent bonding between the transducer element and force sensor unit, resolving the contradiction between measurement precision and device complexity.
2Reliability
If robust mechanical connections are used to withstand environmental influences, then connection strength is improved, but measurement precision deteriorates due to misalignment
Solution Approach 1:
The patent replaces robust but imprecise mechanical connections with wafer bonding technology that provides both environmental robustness and alignment precision. The direct wafer-to-wafer bonding creates a permanent, wear-free connection that withstands environmental influences while maintaining sub-micron alignment accuracy, simultaneously improving both reliability and measurement precision.
3Manufacturing precision
If traditional assembly methods are used, then manufacturing cost is reduced, but manufacturing precision deteriorates due to alignment tolerances
Solution Approach 1:
The patent replaces traditional mechanical assembly methods with wafer bonding technology, enabling precise alignment through semiconductor-level bonding processes. The method allows for precise transducer alignment (sub-micron level) while maintaining ease of manufacture through standardized wafer processing techniques, resolving the contradiction between manufacturing precision and ease of manufacture.
4Duration of action of moving object
If mechanical contact connections are used, then force transmission is direct, but wear occurs reducing sensor endurance
Solution Approach 1:
The patent replaces mechanical contact connections with wafer bonding technology that creates a permanent, wear-free bond between the transducer element and force sensor unit. This eliminates wear and extends sensor endurance while maintaining direct force transmission, resolving the contradiction between sensor endurance and 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
The solution enables precise, cost-effective force measurements with improved accuracy and durability, protecting against environmental factors and mechanical wear, while allowing for versatile applications.
Implementation Method 1
an actuator for transmitting mechanically the externally applied force to the substrate
Implementation Method 2
incorporating piezo-resistive elements and capacitive sensors
Implementation Method 3
incorporating piezo-resistive elements and capacitive sensors
Implementation Method 4
A force sensor package is designed with a substrate and actuator bonded using wafer bonding techniques
Implementation Method 5
featuring overtravel stops for overload protection
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates to a force sensor package (10) for measuring an externally applied force. The force sensor package comprises a substrate (100) comprising a force sensor unit (110), wherein an electrical parameter of the force sensor unit (110) changes when the substrate is deformed. The force sensor package further comprises an actuator (130) for transmitting mechanically the externally applied force to the substrate (100), wherein the actuator (130) is permanently bonded to a top surface of the substrate (100) for deforming the substrate when the external force is applied.