Chip Terminal Assembly Using Conductive Filler Against Reflow Shift

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Solution Overview

Problem

During the reflow process of electronic devices, the contact point between the inner electrode portion and the terminal electrode can become displaced due to the expansion of potting resin, leading to contact failure between the two components.

Innovation Solution

The electronic device incorporates a conductive terminal with an inner electrode portion that includes a space formation portion. This space formation portion creates a filling space between the outer surface of the chip component and the inner electrode portion, which is filled with a conductive agent. This configuration ensures that the terminal electrode and the space formation portion remain connected via the conductive agent, preventing displacement and contact failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the inner electrode portion is fixed to the terminal electrode using elasticity without solder, then the manufacturing process is simplified and solder-free, but the contact between the inner electrode portion and terminal electrode becomes insufficient during reflow due to resin expansion

Engineering Contradiction:

Improvesolder-free assemblyVSAvoidcontact stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A conductive agent is introduced as an intermediary material between the inner electrode portion and the terminal electrode. This conductive agent fills the space formed by the space formation portion and chemically or physically bonds both components together, providing reliable electrical connection and mechanical strength without requiring solder while preventing contact displacement during reflow caused by resin expansion

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the contact point between inner electrode portion and terminal electrode is formed, then electrical connection is achieved, but the contact point becomes displaced during reflow due to expansion of the potting resin

Engineering Contradiction:

Improveelectrical connectionVSAvoidcontact point position

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The space formation portion is designed to create a filling space that is预先 filled with conductive agent before reflow. This preliminary action of filling the space with conductive material prevents the resin expansion during reflow from displacing the contact point, as the conductive agent acts as a buffer that absorbs the expansion stress while maintaining electrical connection

Inventive Principle:

Principle #9Preliminary anti-action

3Reliability

If the conductive agent is filled in the accommodation recess, then the terminal electrode and inner electrode portion can be connected, but the conductive agent is exposed to external space reducing humidity resistance

Engineering Contradiction:

Improveelectrical connectionVSAvoidhumidity exposure

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The filling space formed by the space formation portion is nested within the accommodation recess, and the conductive agent filling this space is subsequently covered and protected by the resin that fills the accommodation recess. This nested structure ensures the conductive agent is not exposed to external environment, improving humidity resistance while maintaining electrical connection functionality

Inventive Principle:

Principle #7Nested doll (Nesting)

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 described solution effectively prevents contact failure between the inner electrode portion and the terminal electrode by maintaining a stable connection through the conductive agent, even in the presence of resin expansion. Additionally, the conductive agent is covered by the resin, enhancing the humidity resistance and reliability of the electronic device.

Implementation Method 1

the terminal electrode and the space formation portion can thereby be connected via this conductive agent

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

the contact point between an inner electrode portion and a terminal electrode may be displaced due to, for example, expansion of the potting resin

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS12340943B2Electronic device

Publication Date: 2025.06.24 TDK CORP

AI summary

An electronic device includes a chip component, a case, a resin, and a conductive terminal. The chip component includes a terminal electrode. The case includes an accommodation recess for accommodating the chip component. The resin is filled in the accommodation recess. The conductive terminal is attachable to the case. The conductive terminal includes an inner electrode portion disposed in the accommodation recess and connected to the terminal electrode. The inner electrode portion includes a space formation portion forming a filling space for a conductive agent with an outer surface of the chip component at a position closer to a bottom surface than to an opening of the accommodation recess.