Oxetane-Based Paste Resin for Solder Aggregation

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Solution Overview

Problem

Conventional thermosetting resin binders inhibit the self-aggregation of solder powders during soldering due to faster curing speeds and lower curing start temperatures, leading to electrical conduction failures and poor bonding strength.

Innovation Solution

A paste thermosetting resin composition containing solder powder with a melting point between 100°C to 240°C, a thermosetting resin binder with a di- or higher functional oxetane compound, and a benzoxazine compound as a curing agent, which slows down the curing reaction and raises the curing start temperature, preventing inhibition of solder powder aggregation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a conventional thermosetting resin binder is used, then the resin cures quickly at low temperature, but the solder powder aggregation is inhibited leading to electrical conduction failures

Engineering Contradiction:

Improvecuring speedVSAvoidelectrical conduction

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the thermosetting resin binder by using oxetane compounds with specific ring structures (4-membered oxetane rings instead of 3-membered epoxy rings) and controlling the curing agent selection. This modifies the curing kinetics to start at higher temperatures and proceed more slowly, allowing solder powder to aggregate properly before the resin solidifies, thus preventing electrical conduction failures while maintaining bonding strength.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent exploits the phase transition of solder powder from solid to liquid state during reflow soldering. By timing the resin curing process to occur after the solder melts and aggregates (phase change completion) but before complete solidification, the invention ensures proper electrical conduction paths are formed. The controlled curing schedule allows the solder to complete its phase transition and form conductive pathways before the resin binder fully cures and locks the structure in place.

Inventive Principle:

Principle #36Phase transitions

2Temperature

If a conventional thermosetting resin binder is used, then the curing reaction starts at low temperature, but the bonding strength between package and substrate is insufficient

Engineering Contradiction:

Improvecuring start temperatureVSAvoidbonding strength

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

The patent raises the curing start temperature by selecting oxetane compounds that require higher activation energy and choosing curing agents with higher reaction temperatures. This parameter change ensures that the resin remains sufficiently fluid during the reflow process to allow proper wetting and adhesion to both the package and substrate surfaces, then cures at temperatures that provide adequate cross-linking density for strong bonding, achieving both high bonding strength and reliable electrical conduction.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the curing speed is fast, then the process time is reduced, but the solder powder self-aggregation is inhibited

Engineering Contradiction:

Improveprocess timeVSAvoidsolder aggregation

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements a periodic or staged curing action where the resin curing process is synchronized with the solder reflow profile. The curing begins after solder melting and aggregation are complete, and continues as the system cools. This staged approach ensures that the solder powder has adequate time to self-aggregate and form proper conductive pathways before the resin curing speed increases and locks the structure, maintaining both reliability and reasonable process time.

Inventive Principle:

Principle #19Periodic action

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 composition allows for effective self-aggregation and integration of solder powders, enhancing bonding strength and preventing electrical insulation, regardless of the solder powder's melting point.

Implementation Method 1

solder powder that has a melting point ranging from 100° C. to 240° C., inclusive

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

a thermosetting resin binder, an activator, and a thixotropy imparting agent

Methodology Applied

Scientific EffectCuring reaction: Chemical Bonding

Data Source

PatentUS10522493B2Paste thermosetting resin composition, semiconductor component, semiconductor mounted article, method for manufacturing semiconductor component, and method for manufacturing semiconductor mounted article

Publication Date: 2019.12.31 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

Provided is a paste thermosetting resin composition containing solder powder, a thermosetting resin binder, an activator, and a thixotropy imparting agent. The solder powder has a melting point ranging from 100° C. to 240° C., inclusive. The thermosetting resin binder contains a main agent and a curing agent. The main agent contains a di- or higher functional oxetane compound.