Multilayer Circuit Substrate Using Sintered Conductive Particles

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Solution Overview

Problem

Existing multilayer circuit substrate manufacturing methods are complex and difficult to produce substrates with a thickness of 100 μm or less due to the need for multiple layers of copper foil and resin composition processing, requiring large-scale equipment and complex processes.

Innovation Solution

A multilayer circuit substrate with a simple configuration is achieved by using sintered conductive particles to form wiring patterns that directly join substrates, eliminating the need for separate adhesive layers and allowing for thinner substrates with a thickness of 40 μm or less, using a solution of conductive particles dispersed in a solvent that is applied and sintered to create the wiring patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If copper foil and resin composition layers are stacked sequentially using conventional methods, then electrical connectivity and insulation are achieved, but the substrate thickness cannot be reduced below 100 μm and the manufacturing process becomes complex

Engineering Contradiction:

Improvesubstrate thicknessVSAvoidmanufacturing process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the functions of copper foil (conductive layer) and resin composition (adhesive layer) into a single integrated layer by coating copper foil with resin composition. This combined layer simultaneously provides electrical conductivity, adhesion, and insulation, eliminating the need for separate adhesive layers and reducing the number of stacking operations required.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the physical and chemical parameters of the copper foil by coating it with resin composition, transforming it from a simple conductive layer into a composite structure with enhanced adhesive properties. This parameter change allows the copper foil to serve multiple functions and enables thinner substrate designs.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If copper foil is coated with resin composition and processed through multiple steps, then wiring patterns are formed, but the substrate thickness remains too large for applications requiring 100 μm or less

Engineering Contradiction:

Improvewiring pattern formationVSAvoidsubstrate thickness

Core Design Contradiction:

Ease of manufactureVSLength of stationary object

Solution Approach 1:

The patent combines the conductive function of copper foil with the adhesive function of resin composition into a single layer, reducing the total number of layers needed in the substrate structure. This merger enables thinner substrates while maintaining ease of wiring pattern formation through the coating process.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If multiple separate layers of copper foil and resin are used, then reliable electrical and mechanical properties are achieved, but the overall substrate thickness increases

Engineering Contradiction:

Improveelectrical and mechanical reliabilityVSAvoidsubstrate thickness

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The patent merges multiple functional layers into a single integrated layer that provides both electrical conductivity and mechanical adhesion. This reduces the total thickness while maintaining reliability through the combined structure's synergistic properties.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a composite material structure by coating copper foil with resin composition, forming a hybrid layer that combines the electrical properties of metal with the adhesive and insulating properties of polymer materials. This composite approach maintains multiple functions in a thinner overall structure.

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

This method simplifies the manufacturing process, reduces substrate thickness, and enhances electrical connectivity while maintaining reliability, making it suitable for high-density circuit applications.

Implementation Method 1

at least one portion of the wiring pattern is configured of a conductive material wherein conductive particles are sintered

Methodology Applied

Scientific EffectSintering: Sintering

Implementation Method 2

using a solution of conductive particles dispersed in a solvent that is applied and sintered to create the wiring patterns

Methodology Applied

Scientific EffectSintering: Sintering

Data Source

PatentUS11355684B2Multilayer circuit substrate and manufacturing method thereof

Publication Date: 2022.06.07 STANLEY ELECTRIC CO LTD

AI summary

An aspect of the invention provides a multilayer circuit substrate that has a simple configuration and is thin. The multilayer circuit substrate has a stacked multiple of substrates and a wiring pattern disposed so to be sandwiched between the stacked multiple of substrates. At least one portion of the wiring pattern is configured of a conductive material wherein conductive particles are sintered. An upper face of the wiring pattern is directly joined to the substrate positioned above the wiring pattern, a lower face of the wiring pattern is directly joined to the substrate positioned below the wiring pattern, and the stacked multiple of substrates are fixed to each other by the wiring pattern.