Solder Powder Resin Connecting Layer for High Density PCB Mounting

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Solution Overview

Problem

The increasing density of electronic components on printed wiring boards, driven by smaller and more functional information devices, has led to narrower terminal pitches, necessitating improved high-density mounting technologies. Existing soldering methods require multiple steps and specialized equipment, increasing costs and complexity.

Innovation Solution

A method involving a connecting layer with a conductive layer formed from a solder powder-containing resin composition, including thermosetting resin, solder powder, and a reducing agent, combined with a thermoplastic resin layer, which is heated to the melting point of the solder powder to establish electrical connections between electronic components and wiring, reducing the number of mounting steps and equipment needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional solder paste application and component mounting steps are used, then reliable electrical connections are achieved, but the number of manufacturing steps and equipment requirements increase

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidnumber of manufacturing steps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the solder paste, flux, and adhesive functions into a single integrated coating layer applied to the circuit board. This multi-functional layer eliminates the need for separate solder paste application and adhesive application steps, reducing manufacturing complexity while maintaining reliable electrical connections and mechanical bonding.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The coating layer serves multiple functions simultaneously: it provides soldering capability for electrical connections, acts as an adhesive for mechanical bonding, and functions as a protective barrier. This multi-functionality reduces the number of separate materials and processing steps required in traditional mounting processes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Manufacturing precision

If multiple specialized equipment are used for each mounting step, then precise control of each process is achieved, but manufacturing cost increases

Engineering Contradiction:

Improveprocess control precisionVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent merges multiple specialized equipment requirements into a single coating application process. By integrating solder paste, flux, and adhesive into one applicatable composition, the manufacturing process requires only one type of application equipment rather than multiple specialized devices, thereby reducing capital investment and operational costs while maintaining process precision.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If solder powder flows freely in the conductive layer at melting temperature, then good electrical connection is achieved, but the resin composition becomes difficult to handle

Engineering Contradiction:

Improveelectrical connection qualityVSAvoidresin composition handleability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent utilizes temperature-dependent parameter changes in the resin composition. At application and storage temperatures, the resin maintains high viscosity for easy handling and stable positioning. During reflow soldering, the resin softens and becomes flowable, allowing solder powder to move and form reliable electrical connections. This dynamic parameter change resolves the contradiction between handleability and connection quality.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The resin composition undergoes a phase transition from a solid-like state at room temperature to a more fluid state at reflow temperatures. This phase change enables the material to be easily applied and positioned initially, then flow appropriately during soldering to ensure good electrical connections without being difficult to handle during application.

Inventive Principle:

Principle #36Phase transitions

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 approach simplifies the mounting process, reduces costs by eliminating the need for additional equipment, and enhances the bonding strength and environmental resistance of solder joints, while maintaining high-quality connections.

Implementation Method 1

heating the connecting layer to the melting point temperature or higher of the solder powder

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

a conductive layer formed of a solder powder-containing resin composition containing thermosetting resin, solder powder, and a reducing agent

Methodology Applied

Scientific EffectThermosetting:

Data Source

PatentUS9807889B2Method of mounting electronic component to circuit board

Publication Date: 2017.10.31 SENJU METAL IND CO LTD

AI summary

An method of mounting electronic component includes: providing a connecting layer between a wiring and an electronic component, the connecting layer including a conductive layer formed of a solder powder-containing resin composition containing thermosetting resin, solder powder, and a reducing agent and one or two layers of a thermoplastic resin layer formed of thermoplastic resin; and electrically connecting the electronic component to the wiring through the connecting layer.