Stress Decoupled Piezoresistive Pressure Sensor
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Solution Overview
Problem
Existing MEMS pressure sensors face challenges in achieving effective stress decoupling, which is crucial for accurate pressure measurement, often requiring complex processes and multiple wafers, leading to increased costs and reduced shock resistance.
Innovation Solution
A MEMS pressure sensor design featuring a semiconductor substrate with a stress decoupling structure that includes buried empty spaces and a pressure channel, manufactured using a double Venezia process, allowing for improved stress decoupling with reduced process complexity and device height, utilizing a single wafer instead of a triple stack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional stress decoupling methods are used in MEMS pressure sensors, then stress decoupling is achieved, but device complexity and manufacturing cost increase due to requiring multiple wafers and complex processes
Solution Approach 1:
The semiconductor substrate is divided into two distinct portions: a first portion containing a first buried empty space and a second portion containing a second buried empty space. These portions are stress decoupled from each other while remaining part of the same substrate, eliminating the need for multiple wafers and complex stacking processes.
Solution Approach 2:
Instead of using multiple wafers stacked in the vertical dimension to achieve stress decoupling, the invention transitions to a single-wafer approach with buried empty spaces created within the substrate volume. This dimensional reorganization maintains stress decoupling functionality while simplifying the manufacturing process and reducing device complexity.
2Reliability
If multiple wafers are stacked to achieve stress decoupling, then stress decoupling is improved, but shock resistance decreases and manufacturing cost increases
Solution Approach 1:
The substrate is segmented into stress-isolated portions through the introduction of buried empty spaces, achieving stress decoupling within a single monolithic structure. This eliminates the interfaces between multiple wafers that would be vulnerable to shock, thereby improving shock resistance while maintaining stress decoupling performance.
Solution Approach 2:
The invention converts what would traditionally require multiple separate components (wafers) into a single integrated substrate with strategically placed empty spaces. This transformation turns the potential weakness of single-substrate construction into a strength by eliminating inter-wafer interfaces that are prone to failure under shock, while the buried empty spaces provide the necessary stress decoupling.
3Reliability
If traditional pressure sensor manufacturing processes are used, then pressure sensing is achieved, but manufacturing cost and process complexity increase
Solution Approach 1:
Multiple functional elements (pressure sensing regions, stress decoupling structures, and fluidic pathways) are merged into a single semiconductor substrate. The first and second portions with their respective buried empty spaces are integrated in one substrate, eliminating the need for separate wafers and reducing manufacturing steps, material costs, and assembly complexity.
Solution Approach 2:
The single semiconductor substrate performs multiple functions simultaneously: it provides the pressure sensing functionality through piezoresistive elements, achieves stress decoupling through the divided portions and buried empty spaces, and enables fluidic connection through the pressure channel. This multi-functionality in a single component simplifies manufacturing and reduces overall system 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 design achieves enhanced stress decoupling and shock resistance while reducing manufacturing complexity and costs, enabling more robust and cost-effective pressure sensors for applications like automotive use.
Implementation Method 1
a first piezoresistive pressure membrane formed above the first buried empty space in the first portion of the semiconductor substrate
Data Source
AI summary
Embodiments provide a MEMS (Micro Electro Mechanical System) pressure sensor comprising a semiconductor substrate, wherein the semiconductor substrate comprises a stress decoupling structure adapted to stress decouple a first portion of the semiconductor substrate from a second portion of the semiconductor substrate, wherein the first portion of the semiconductor substrate comprises a first buried empty space, wherein the second portion of the semiconductor substrate comprises a second buried empty space, and wherein the semiconductor substrate comprises a pressure channel fluidically connecting the first buried empty space and the second buried empty space.