Insulated Circuit Board Bonding to Prevent Voids in Thick Resin Layers

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Solution Overview

Problem

In insulated circuit substrates with thermosetting resin insulating layers, thickened circuit layers can lead to insufficient pressurization in regions without metal pieces, resulting in voids and compromised insulating properties.

Innovation Solution

A manufacturing method that uses a pressurizing jig with a cushion material and a guide wall portion to uniformly pressurize the resin material and bond the metal piece to the insulating resin layer, even when the metal piece is disposed in a circuit pattern shape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rubber-like elastic body is used to pressurize the resin composition and metal piece, then bonding is improved, but the peripheral portion spreads outward causing metal piece shift and bonding defects

Engineering Contradiction:
Improvebonding strengthVSAvoidpositioning accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The cushion material is selectively disposed only in regions where metal pieces are not disposed, creating localized pressurization zones. This prevents the peripheral portion from spreading outward and causing metal piece shift, while still providing sufficient pressurization for bonding in the appropriate regions, thereby resolving the contradiction between bonding strength and positioning accuracy

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The cushion material acts as an intermediary element between the pressurizing device and the resin composition/metal piece assembly. It mediates the pressurization force to prevent direct contact and spreading of peripheral portions, ensuring accurate positioning while maintaining bonding strength

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If the metal piece is disposed on resin composition before curing and pressurized and heated, then bonding is achieved, but insufficient pressurization in metal-free regions generates voids

Engineering Contradiction:
Improvebonding strengthVSAvoidvoid formation
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The cushion material is selectively disposed only in regions where metal pieces are not disposed, creating local differentiation in pressurization distribution. This ensures sufficient pressurization in metal-free regions to prevent void formation, while avoiding interference with bonding in regions where metal pieces are disposed, thereby resolving the contradiction between bonding strength and void prevention

Inventive Principle:
Principle #3Local quality

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 method ensures reliable bonding of the metal piece and insulating resin layer, preventing voids and maintaining excellent insulating properties, even with thickened circuit layers.

Implementation Method 1

the resin composition is cured to constitute the insulating resin layer and the insulating resin layer and the metal piece are bonded to each other

Methodology Applied
Scientific EffectCuring: Phase Change

Implementation Method 2

the metal piece and the resin material are pressurized in the laminating direction by a pressurizing jig

Methodology Applied
Scientific EffectPressurization: Compression

Implementation Method 3

the metal piece and the resin material are pressurized and heated at least in a laminating direction, in which the bonding step

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP4131356B1Insulated circuit board manufacturing method
Publication Date: 2025.05.21 MITSUBISHI MATERIALS CORP
  • EP4131356B1 patent drawingFigure 1
  • EP4131356B1 patent drawingFigure 2A~2B
  • EP4131356B1 patent drawingFigure 3

AI summary

An insulated circuit substrate manufacturing method of the present invention includes a metal piece disposing step of disposing the metal piece in a circuit pattern shape on a resin material serving as the insulating resin layer and a bonding step of bonding the insulating resin layer and the metal piece by pressurizing and heating the resin material and the metal piece at least in a laminating direction. In the bonding step, the metal piece and the resin material are pressurized in the laminating direction by a pressurizing jig that includes a cushion material disposed on a side of the metal piece and a guide wall portion disposed at a position facing a peripheral portion of the cushion material, and the peripheral portion of the cushion material is brought into contact with the guide wall portion during pressurization.