Capacitive Sensor Trench Porosification Method

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Solution Overview

Problem

Existing capacitive sensors with porous materials for gas and humidity detection face limitations in sensitivity due to the thickness of the porous dielectric material, which is often limited, and contamination issues during the production process.

Innovation Solution

The method involves etching trenches in a non-porous support material followed by porosification, filling these trenches with conductive material to form electrodes, and using a porous material with high open porosity and nano-porous characteristics to enhance sensitivity and reduce contamination, allowing for improved electrical insulation and detection of low humidity levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the thickness of the porous dielectric material is increased to improve sensitivity, then the sensitivity of the sensor is improved, but the production complexity increases requiring several deposits

Engineering Contradiction:
ImprovesensitivityVSAvoidproduction complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent performs porosification of the support material before depositing the dielectric material. This preliminary action creates the porous structure in advance, allowing the dielectric material to be deposited within the porous network in a single step, thereby achieving thick porous dielectric layers without requiring multiple deposits while maintaining high sensitivity

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If trenches are formed in porous material to create electrodes, then the sensor can be produced, but the trenches are less precisely defined and pores may be damaged

Engineering Contradiction:
Improvesensor productionVSAvoidtrench definition precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent inverts the conventional sequence by first forming trenches in a non-porous support material and then performing porosification on the trench walls and bottom. This inversion ensures that trenches are precisely defined in the solid material before pores are created, avoiding pore damage and maintaining precise trench geometry while enabling subsequent electrode formation

Inventive Principle:
Principle #13The other way round (Inversion)

3Manufacturing precision

If trenches are etched before porosification, then trenches are more precisely defined and pore quality is improved, but the process sequence becomes more critical

Engineering Contradiction:
Improvetrench definition precisionVSAvoidprocess sequence complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent establishes a fixed preliminary sequence where trenches are etched into the non-porous support first, creating well-defined structures. Only after trench formation is the porosification step performed on the trench walls and bottom. This preliminary action approach locks in the precise trench geometry before pore creation, ensuring manufacturing precision while managing process sequence complexity through clear step ordering

Inventive Principle:
Principle #10Preliminary action

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 results in a capacitive sensor with improved sensitivity and the ability to detect low humidity levels effectively, while minimizing contamination and reducing the complexity of the production process, enabling better electrical insulation and enhanced detection capabilities.

Implementation Method 1

have a capacity capable of varying depending on a quantity of gas or liquid adsorbed by this material

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

This makes it possible to obtain a large developed surface area and to fix a large number of molecules, in particular water molecules when the capacitive sensor is a humidity sensor

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP2850420B1Method for producing a capacitive sensor
Publication Date: 2019.11.06 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2850420B1 patent drawingFigure 1A~1B
  • EP2850420B1 patent drawingFigure 2A~2D
  • EP2850420B1 patent drawingFigure 2E~4

AI summary

A method for producing a capacitive sensor, comprising steps consisting of: (a) forming trenches (105) in a support (100) made from at least one given material by etching said at least one given material, (b) making said given material porous at the walls and the bottom of the trenches, (c) filling the trenches (105) with a conductive material (110).