Wiring Board Adhesive Layer Thermal Expansion Matching

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Solution Overview

Problem

Existing wiring boards with built-in electronic components face challenges in maintaining connectivity and structural integrity, particularly due to thermal expansion mismatches and peeling risks between conductor layers and core materials.

Innovation Solution

A wiring board design featuring multiple laminated layers, including core layers with core materials, an intermediate insulating layer without core material, and embedded electronic components, with at least one core layer having a multilayer structure comprising a resin layer and an adhesive layer, and conductor layers laminated on the adhesive layer, enhancing connectivity and reducing peeling risks through thermal expansion coefficient matching and improved structural strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conductor layers are directly laminated on core material, then structural strength is improved, but thermal expansion mismatch causes peeling between layers

Engineering Contradiction:

Improvestructural strengthVSAvoidconnectivity reliability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

An adhesive layer is introduced as an intermediary between the conductor layer and the core material. This adhesive layer has a thermal expansion coefficient that matches the conductor layer, preventing peeling and maintaining reliable connectivity while still providing structural strength through the laminated construction.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The core layer is constructed as a composite structure with a core material layer and an adhesive layer laminated together. This composite structure combines the mechanical strength of the core material with the thermal expansion matching properties of the adhesive layer, resolving the contradiction between structural strength and connectivity reliability.

Inventive Principle:

Principle #40Composite materials

2Strength

If core layers with core material are used, then structural strength is improved, but peeling risks increase due to thermal expansion mismatches

Engineering Contradiction:

Improvestructural strengthVSAvoidpeeling risk

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The adhesive layer serves as a mediator between the core material and the conductor layer. It has thermal expansion properties that match the conductor layer, preventing peeling caused by thermal expansion mismatches while maintaining the structural strength provided by the core material.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The adhesive layer is applied locally at the interface between the conductor layer and core material where peeling occurs. This localized application of material with specific thermal expansion properties eliminates the harmful peeling effect without compromising the overall structural strength of the core layers.

Inventive Principle:

Principle #3Local quality

3Reliability

If intermediate insulating layer without core material is used, then peeling risks are reduced, but structural strength decreases

Engineering Contradiction:

Improveconnectivity reliabilityVSAvoidstructural strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The core layer is segmented into two distinct layers: a core material layer that provides structural strength and an adhesive layer that prevents peeling. This segmentation allows each layer to perform its specific function optimally, with the core material layer maintaining structural integrity and the adhesive layer ensuring reliable connectivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The core layer is constructed as a composite of core material and adhesive material. This composite structure combines the high strength properties of the core material with the peeling-prevention properties of the adhesive material, resolving the contradiction between structural strength and reliability.

Inventive Principle:

Principle #40Composite materials

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 design improves connectivity and structural strength by matching thermal expansion coefficients and reducing peeling risks, while allowing for a thinner profile and reduced contact with electronic components, thus enhancing the reliability and performance of the wiring board.

Implementation Method 1

improving connectivity and reducing peeling risks through thermal expansion coefficient matching

Methodology Applied

Scientific EffectThermal expansion coefficient matching: Thermal Expansion

Data Source

PatentUS10186486B2Wiring board

Publication Date: 2019.01.22 IBIDEN CO LTD

AI summary

A wiring board includes conductor layers, core layers including a first core layer and a second core layer formed such that each of the first and second core layers includes a core material, an intermediate insulating layer formed between the first core layer and second core layer such that the intermediate insulating layer does not contain a core material, and an electronic component positioned between the first core layer and second core layer such that the electronic component is embedded in the intermediate insulating layer. At least one of the first and second core layers has a multilayer structure including a resin layer and an adhesive layer laminated on the resin layer such that the resin layer includes the core material and that the adhesive layer does not contain a core material, and the conductor layers include a conductor layer laminated on the adhesive layer of the multilayer structure.