Stacked Electrode Structure for Heat-Resistant Pressure Sensors

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Solution Overview

Problem

Existing strain resistance films in pressure sensors deteriorate in high-temperature or high-humidity environments due to deterioration of the contact layer, leading to reduced reliability of the electrode and pressure sensor.

Innovation Solution

A stacked electrode structure comprising a contact layer, a diffusion prevention layer, and a mounting layer is used, where the diffusion prevention layer and mounting layer cover the contact layer to isolate it from the external environment, preventing exposure and deterioration, thereby enhancing heat and moisture resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a contact layer is formed on the strain resistance film to enable electrical connection, then electrical conductivity and adhesion are improved, but the contact layer deteriorates in high-temperature or high-humidity environments, reducing reliability

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidenvironmental deterioration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A diffusion prevention layer is introduced as an intermediary between the contact layer and the mounting layer. This intermediate layer prevents harmful diffusion of metal atoms from the mounting layer to the contact layer and strain resistance film, thereby protecting the contact layer from environmental deterioration while maintaining electrical connection reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrode structure uses a composite multi-layer configuration (contact layer + diffusion prevention layer + mounting layer) where each layer has specific material properties. The contact layer (e.g., Ti, Cr, W) provides adhesion and conductivity, the diffusion prevention layer (e.g., Ru, Rh, Pd, Pt, Au) prevents atomic diffusion, and the mounting layer provides mechanical support and environmental protection, collectively resolving the deterioration issue

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If the contact layer is exposed to enable electrical connection, then electrical signal extraction is achieved, but the contact layer is exposed to external environment causing deterioration

Engineering Contradiction:

Improveelectrical signal extractionVSAvoidcontact layer stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The contact layer is nested within the multi-layer electrode structure, surrounded by the diffusion prevention layer and mounting layer. This nesting configuration allows the contact layer to perform its electrical function while being protected from environmental exposure, preventing deterioration without compromising electrical signal extraction capability

Inventive Principle:

Principle #7Nested doll (Nesting)

3Reliability

If a multi-layer electrode structure is implemented to protect the contact layer, then heat resistance and moisture resistance are improved, but device complexity increases

Engineering Contradiction:

Improveheat and moisture resistanceVSAvoidelectrode structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The electrode is segmented into three distinct functional layers: contact layer for adhesion and conductivity, diffusion prevention layer for blocking atomic diffusion, and mounting layer for structural support and environmental protection. This segmentation allows each layer to be optimized for its specific function while collectively providing excellent heat and moisture resistance

Inventive Principle:

Principle #1Segmentation

4Reliability

If the diffusion prevention layer covers the contact layer completely, then protection from environmental degradation is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improveprotection from degradationVSAvoidlayer alignment precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The diffusion prevention layer is designed to extend beyond the boundaries of the contact layer, providing excessive coverage that ensures complete protection of the contact layer edges. This excessive action compensates for potential alignment variations during manufacturing, maintaining protection effectiveness without requiring extremely high precision

Inventive Principle:

Principle #16Partial or excessive 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

The stacked electrode configuration effectively protects the contact layer from environmental degradation, ensuring the pressure sensor maintains excellent heat and moisture resistance, adhesion, and electrical performance even in harsh conditions.

Implementation Method 1

a diffusion prevention layer overlying the contact layer... the diffusion prevention layer can isolate the contact layer from the external environment such as air and can prevent the contact layer from being exposed to the external environment

Methodology Applied

Scientific EffectDiffusion prevention: Diffusion Barrier

Data Source

PatentUS12474225B2Stacked electrode, electrode-equipped strain resistance film, and pressure sensor

Publication Date: 2025.11.18 TDK CORP

AI summary

A stacked electrode is provided on a strain resistance film, wherein: the strain resistance film contains Cr and Al; the stacked electrode has a contact layer that overlaps the strain resistance film, a diffusion prevention layer that overlaps the contact layer, and a mounting layer that overlaps the diffusion prevention layer; and the diffusion prevention layer or the mounting layer covers the contact layer so that an end surface of the contact layer is not exposed.