Gas Sensor Elevated Structures Prevent Sensitive Material Expansion

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Solution Overview

Problem

Existing gas sensors face challenges in maintaining a high-quality and reliable detection of multiple analytes due to the expansion of sensitive materials beyond designated areas on the substrate, leading to inefficiencies in coverage and accuracy.

Innovation Solution

The implementation of elevated structures within the maximal admissible coverage area on the substrate prevents the expansion of sensitive materials by utilizing insulating or conducting layers, manufactured through standard CMOS processes, which are designed to stop the material's expansion due to surface tension effects, thereby maintaining precise coverage and preventing spillage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If sensitive material is applied to the substrate without expansion inhibitors, then the manufacturing process is simple, but the sensitive material expands beyond the designated area leading to poor coverage control and reduced sensor reliability

Engineering Contradiction:
Improvecoverage controlVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Elevated structures are manufactured on the substrate before the sensitive material is applied. These pre-formed structures serve as expansion inhibitors that define the boundaries of the sensitive film area, preventing the material from spreading beyond the designated region during the coating process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The substrate surface is segmented into distinct regions by the elevated structures, which create physical barriers that divide the continuous sensitive material into controlled areas. This segmentation ensures that the sensitive film remains confined to specific zones, improving coverage control and sensor reliability.

Inventive Principle:
Principle #1Segmentation

2Reliability

If elevated structures are added to prevent material expansion, then coverage control is improved, but the device complexity and manufacturing steps increase

Engineering Contradiction:
Improvesensor reliabilityVSAvoidmanufacturing ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The elevated structures serve multiple functions: they act as expansion inhibitors to define the sensitive film area, serve as support structures for the sensitive material, and can potentially function as electrical contacts or interconnection elements. This multi-functionality reduces the need for separate components, simplifying the overall manufacturing process despite the added complexity of the elevated structures.

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

3Measurement precision

If the sensitive material is allowed to cover the entire substrate area, then the material usage is maximized, but the detection precision is reduced due to lack of controlled coverage

Engineering Contradiction:
Improvedetection precisionVSAvoidmaterial coverage area
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The elevated structures create zones with different properties on the substrate. The areas within the elevated structures are designated for sensitive material deposition with high detection precision, while areas outside these structures remain free of sensitive material. This local differentiation ensures that the sensitive material is concentrated in specific regions where precise detection is required, rather than being uniformly distributed across the entire substrate.

Inventive Principle:
Principle #3Local quality

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 approach ensures a high-quality and reliable gas sensor with controlled sensitive film coverage, allowing for precise detection of analytes and minimizing the area used on the substrate, enhancing the sensor's accuracy and efficiency.

Implementation Method 1

it is desired that the sensitive material does not extend outside such maximal admissible coverage area designated for the sensitive film. For this purpose, it is envisaged to provide one or more elevated structures in said maximal admissible coverage area for preventing the sensitive material to expand therefrom when being applied thereto

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Data Source

PatentEP2952885B1Gas sensor
Publication Date: 2016.07.27 SENSIRION AG
  • EP2952885B1 patent drawingFigure 1a~1c
  • EP2952885B1 patent drawingFigure 2a~3
  • EP2952885B1 patent drawingFigure 4~8d

AI summary

A gas sensor comprises a set of one or more sensor cells (SC) and a substrate (1). Each sensor cell (SC) of the set comprises a sensitive film (42) built from a sensitive material (4) covering an area of the substrate (1). One or more elevated structures (2) are manufactured in or around said area for preventing the sensitive material (4) to expand when being applied thereto.