Ceramic Substrate Hollow Structure for Thermal Stress Relief

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Solution Overview

Problem

Ceramic substrates with heat dissipation layers suffer from defects such as cracks and interfacial peeling due to thermal stress, leading to reduced flexural strength, especially during thermal shocks like firing and reflow treatment.

Innovation Solution

Incorporating a first hollow between the outer surface of the heat dissipation portion and the inner wall of the housing portion in the ceramic substrate, allowing thermal expansion and reducing thermal stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a heat diffusion layer is provided in the multilayer substrate to improve heat dissipation performance, then heat dissipation performance is improved, but thermal stress causes defects such as cracks and interfacial peeling

Engineering Contradiction:

Improveheat dissipation performanceVSAvoiddefect occurrence

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent applies local quality by providing a hollow portion only in the heat diffusion layer at specific locations where thermal stress concentrates, rather than modifying the entire structure. This localized modification allows the heat diffusion layer to expand thermally without generating excessive stress, preventing cracks and interfacial peeling while maintaining heat dissipation performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes thermal expansion by designing a hollow portion in the heat diffusion layer that allows the material to expand freely during thermal cycles. The hollow space accommodates the volume increase of the heat diffusion layer when heated, reducing thermal stress and preventing defects such as cracks and interfacial peeling.

Inventive Principle:

Principle #37Thermal expansion

2Ease of manufacture

If thermal shock is applied during firing or reflow treatment to sinter the ceramic substrate, then the ceramic substrate is formed, but defects occur in the heat diffusion layer and ceramic layer

Engineering Contradiction:

Improvefiring processVSAvoiddefect occurrence

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by incorporating the hollow portion in the heat diffusion layer before the firing process. This pre-designed structural feature allows the heat diffusion layer to accommodate thermal stress during subsequent firing and reflow treatments, preventing cracks and defects from forming during these manufacturing processes.

Inventive Principle:

Principle #10Preliminary action

3Temperature

If the heat diffusion layer is thermally coupled to the heat generation element to improve heat emission, then heat dissipation performance is improved, but thermal stress deteriorates substrate flexural strength

Engineering Contradiction:

Improveheat emission efficiencyVSAvoidsubstrate flexural strength

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

The patent applies local quality by positioning the hollow portion specifically in the heat diffusion layer where thermal stress concentrates, rather than modifying the entire substrate structure. This localized modification maintains the thermal coupling between the heat diffusion layer and heat generation element while preventing stress-induced deterioration of substrate flexural strength.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes thermal expansion by providing a hollow portion that allows the heat diffusion layer to expand freely during thermal cycles. This reduces thermal stress accumulation that would otherwise deteriorate the substrate flexural strength, while maintaining effective thermal coupling for heat emission.

Inventive Principle:

Principle #37Thermal expansion

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

Prevents defects in the heat dissipation and ceramic layers, maintaining substrate flexural strength and enhancing thermal shock resistance.

Implementation Method 1

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS20250214324A1Ceramic substrate and method for manufacturing ceramic substrate

Publication Date: 2025.07.03 MURATA MFG CO LTD

AI summary

A ceramic substrate includes a multilayer body including stacked ceramic layers and a housing portion in an interior of the multilayer body and a heat dissipation portion in the housing portion. A first hollow is provided between at least a portion of an outer surface of the heat dissipation portion and an inner wall surface of the housing portion in an extension direction of the heat dissipation portion.