Semiconductor Pressure Sensor Layout for Gas Permeation Stability
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Solution Overview
Problem
Semiconductor pressure sensors experience variations in characteristics due to permeation of gases like hydrogen, which affect their performance.
Innovation Solution
The design includes a first silicon substrate with a recessed part and a second silicon substrate forming a diaphragm that hermetically seals a space, with additional permeation gas stagnation chambers separated from the main chamber to inhibit gas permeation, using electrical resistance to measure diaphragm deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hermetically sealed chamber is used to detect pressure, then measurement precision is improved, but permeation gas can still enter the chamber causing variation in characteristics
Solution Approach 1:
The patent divides the sealed chamber into multiple independent sealed chambers (first sealed chamber and second sealed chamber). The first sealed chamber contains the diaphragm for pressure detection, while the second sealed chamber is positioned away from the first to create spatial separation. This segmentation prevents permeation gas from affecting both chambers simultaneously, thereby maintaining measurement precision while improving reliability against gas permeation effects.
2Reliability
If the sensor structure is made more complex to prevent gas permeation, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent addresses gas permeation prevention not by adding complex barriers within the same dimension, but by utilizing spatial dimensionality - positioning the second sealed chamber at a location physically separated from the first sealed chamber. This dimensional approach to problem-solving provides reliability against permeation gas without significantly increasing structural complexity, as the solution relies on spatial arrangement rather than complex additional components.
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 configuration reduces variations in sensor characteristics by slowing down gas permeation, maintaining reliability without increasing chip size or cost.
Implementation Method 1
a gauge resistance configured to output a deformation amount of the diaphragm by using electrical characteristics
Implementation Method 2
when a pressure of a permeation gas having high permeability, such as a hydrogen gas, is detected, the permeation gas may permeate into the semiconductor pressure sensor, causing variation in characteristics
Data Source
AI summary
A semiconductor pressure sensor includes: a first silicon substrate including a first recessed part; and a second silicon substrate including a diaphragm covering a first space in the first recessed part, the second silicon substrate being configured to hermetically seal the first space. In cross-section, a plurality of second spaces are hermetically sealed in a state of being separated away from the first space between the first silicon substrate and the second silicon substrate, and are provided in one of or each of a first end side and a second end side of the first space.