Integrated Moisture Sensor Assembly with CMOS Signal Processing

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Solution Overview

Problem

Existing humidity sensor arrangements are either complex in design due to the need for multiple semiconductor substrates or lack efficient integration of signal processing and temperature measurement, making them less compact and less precise.

Innovation Solution

A compact humidity sensor arrangement featuring a plate-shaped semiconductor substrate with an integrated package-less CMOS signal processing module and a capacitive humidity sensor, where the sensor and signal processing module are electrically connected via vias, and include a temperature sensor for precise humidity measurement, eliminating the need for bonding wires and additional housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a capacitive moisture sensor is integrated on a semiconductor substrate with signal processing module, then device complexity is reduced and compactness is improved, but manufacturing precision requirements increase due to the need for precise vias and integration

Engineering Contradiction:
Improvestructure complexityVSAvoidvia precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent combines the moisture sensor, signal processing module, and temperature sensor into a single integrated semiconductor substrate structure. The sensor elements are formed directly on the substrate with vias providing electrical connections, eliminating the need for separate packages and bonding wires. This merging approach reduces overall device complexity while maintaining manufacturing feasibility through standard semiconductor fabrication processes.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If bonding wires and additional housing are used for contacting the sensor, then ease of manufacture is improved, but device volume and space requirements increase

Engineering Contradiction:
Improvecontacting easeVSAvoiddevice volume
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The patent extracts and eliminates the bonding wires and separate housing components by integrating all necessary functions directly into the semiconductor substrate. The spherical contacting elements are formed directly on the substrate surface, removing the need for wire bonding and additional protective housing, thereby significantly reducing device volume while maintaining manufacturability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If temperature sensor is integrated in the signal processing module, then measurement precision is improved through thermal compensation, but device area requirements increase

Engineering Contradiction:
Improvehumidity measurement precisionVSAvoidsubstrate area
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The temperature sensor is integrated within the signal processing module structure on the same semiconductor substrate. This merging allows the temperature sensing function to share the substrate real estate with the signal processing circuitry, minimizing additional area requirements while enabling thermal compensation to improve humidity measurement precision.

Inventive Principle:
Principle #5Merging (Combining)

4Device complexity

If vias are used to electrically connect elements on opposite sides of the semiconductor substrate, then device compactness is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveintegration compactnessVSAvoidvia fabrication complexity
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The vias are formed as integral parts of the semiconductor substrate fabrication process itself, utilizing self-aligned techniques where the via formation is automatically positioned relative to the sensor elements. This self-service approach to via creation reduces manufacturing complexity despite the increased integration density, as the via formation becomes an automated step in the standard fabrication sequence rather than a separate manual process.

Inventive Principle:
Principle #25Self-service

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 solution results in a highly compact, precise, and efficient humidity sensor with integrated temperature measurement, reducing space requirements and thermal interference, and enabling automated assembly without the need for bonding wires.

Implementation Method 1

a capacitive moisture sensor (3), which is electrically conductively connected to the signal processing module (2)

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

At least one temperature sensor (5) is also integrated in the signal processing module (2)

Methodology Applied
Scientific EffectTemperature sensing: Thermistor

Data Source

PatentEP2657691B1Moisture sensor assembly
Publication Date: 2018.08.29 E E ELEKTRONIK GES
  • EP2657691B1 patent drawingFigure 1~2
  • EP2657691B1 patent drawingFigure 3~4

AI summary

The moisture sensor arrangement has an integrated signal processing component (2) that is arranged on top side of a plate-like semiconductor substrate (1). A capacitive moisture sensor (3) is connected electrically and conductively to integrated signal processing component, and is arranged on opposite side of substrate. Plated through-holes (4) of semiconductor substrate are electrically connected to one another over elements on sides of semiconductor substrate. A temperature sensor (5) is integrated with the integrated signal processing component.