Stress-Compensated Sensor Chip for Accurate Pressure Measurement

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Solution Overview

Problem

Pressure sensors and other stress-sensitive sensors are prone to mechanical stress during mounting and operation, which can affect their accuracy due to stress transmission through electrical or mechanical contacts, and existing compensation methods may not fully address these issues.

Innovation Solution

A sensor arrangement with a stress sensor integrated on the same chip as the sensor, which measures stress induced during mounting or operation and provides a stress-compensated signal by using a compensator to adjust the sensor signal, potentially using piezoresistive elements and Wheatstone bridges for accurate stress detection and compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sensor is mounted to a carrier and electrically connected thereto, then electrical connection and mechanical support are achieved, but mechanical stress is transmitted to stress-sensitive elements through electrical contacts or mechanical joining elements

Engineering Contradiction:
Improvesensor mounting stabilityVSAvoidsensor measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The sensor system is divided into separate functional components: the sensor chip containing stress-sensitive elements, the carrier providing mechanical support, and a stress sensor specifically dedicated to measuring mechanical stress. This segmentation allows each component to perform its specialized function without interfering with the others, resolving the contradiction between stable mounting and measurement accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A stress sensor acts as an intermediary element between the carrier and the sensor chip. It measures the mechanical stress transmitted through the mounting structure and provides compensation signals that allow the main sensor to maintain measurement accuracy despite the presence of mounting stresses.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If standard CMOS processes are used for integrating circuitry on the first substrate, then manufacturing compatibility and cost-effectiveness are improved, but the ability to integrate stress compensation functionality on the same chip is limited

Engineering Contradiction:
Improvemanufacturing process compatibilityVSAvoidchip integration complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The sensor chip is designed to perform multiple functions: sensing the primary physical quantity (pressure, temperature, etc.), sensing mechanical stress, and processing compensation signals. By making the chip multi-functional and integrating both the main sensor and stress sensor on the same substrate using compatible CMOS processes, the patent achieves both manufacturing ease and stress compensation capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 integration of a stress sensor on the chip allows for real-time stress compensation, improving the accuracy of sensor readings by accounting for stress-induced variations, thereby providing more reliable measurements of the intended variable, such as pressure or temperature.

Implementation Method 1

the stress sensor comprises a resistive element that follows the piezoresistive effect

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Implementation Method 2

potentially using piezoresistive elements and Wheatstone bridges for accurate stress detection and compensation

Methodology Applied
Scientific EffectWheatstone bridge: Wheatstone Bridge

Data Source

PatentEP3056865B1Sensor arrangement
Publication Date: 2019.09.04 SENSIRION AG
  • EP3056865B1 patent drawingFigure 1~2
  • EP3056865B1 patent drawingFigure 3
  • EP3056865B1 patent drawingFigure 4~7

AI summary

A sensor arrangement (100) comprises a sensor chip (200). The sensor chip (200) comprises a sensor (300) sensitive to a variable to be measured. The sensor (300) provides a sensor signal (x). The sensor chip (200) further comprises a stress sensor (400) sensitive to stress in the sensor chip (200). The stress sensor (400) provides a stress signal (y). A compensator (500) of the sensor arrangement (100) is configured to determine a stress compensated sensor signal (z) dependent on the sensor signal (x) and the stress signal (y).