Electronic Component Package With Discontinuous Solder Precoat

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Solution Overview

Problem

Existing electronic component packages face challenges in downsizing, cost reduction, and maintaining electromagnetic shielding while preventing dew condensation, due to issues with conductive adhesives and fluxless soldering processes that affect the shape and size of ventilation holes and increase component costs.

Innovation Solution

An electronic component package design featuring a circuit board with a ring-shaped bonding pattern and a lid with a discontinuous solder precoat, where the ventilation hole is formed by exposing the lid's bonding surface to prevent wetting by fluxless solder, allowing for controlled bonding and reduced component costs without gold plating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a protective film (nitride film) is formed on the semiconductor element surface to improve humidity resistance, then airtight structure becomes unnecessary, but high-frequency characteristics are degraded

Engineering Contradiction:

Improvehumidity resistanceVSAvoidhigh-frequency characteristics degradation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies a protective film only to specific areas where humidity resistance is needed, while maintaining local quality variations that preserve high-frequency characteristics in critical areas. The film thickness and coverage are optimized to balance protection and performance.

Inventive Principle:

Principle #3Local quality

2Reliability

If a ventilation hole is provided to prevent dew condensation, then humidity resistance is improved, but electromagnetic shielding is compromised

Engineering Contradiction:

Improvedew condensation preventionVSAvoidelectromagnetic wave leakage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a lid with a flexible sealing structure that can accommodate a small ventilation hole while maintaining electromagnetic shielding. The thin film and sealing mechanisms allow minimal opening for ventilation without compromising the shielding effectiveness against electromagnetic waves.

Inventive Principle:

Principle #30Flexible shells and thin films

3Ease of manufacture

If conductive adhesive is used to bond circuit board to shielding component to form ventilation hole, then bonding is achieved, but shape stabilization is difficult and cost increases

Engineering Contradiction:

Improvebonding capabilityVSAvoidventilation hole shape stability

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces expensive conductive adhesive with a inexpensive unbonded part structure in the bonding layer. This disposable-like approach uses a simple geometric feature (unbonded area) instead of costly materials, achieving both cost reduction and shape stabilization without relying on adhesive properties.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Ease of manufacture

If fluxless solder is used to bond lid to circuit board, then cost is reduced and wettability is improved, but solder bridge risk increases

Engineering Contradiction:

Improvebonding cost and wettabilityVSAvoidsolder bridge prevention

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent performs preliminary action by forming a discontinuous solder precoat pattern on the lid before bonding. This pre-defined solder distribution prevents excessive solder flow that could cause bridges, while still using inexpensive fluxless solder. The precoat acts as a controlled barrier that maintains reliability without sacrificing cost benefits.

Inventive Principle:

Principle #10Preliminary 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

This design enables a low-cost, downsized electronic component package with effective electromagnetic shielding and dew condensation prevention, while maintaining the integrity of the ventilation hole and reducing the risk of solder bridges.

Implementation Method 1

a discontinuous part where a bonding surface of the lid is exposed is formed and parts other than the discontinuous part are continuous, and that bonds the bonding pattern to a bonding surface of the lid; and a ventilation hole that is formed by providing a bonding surface of the lid exposed in a discontinuous part of the solder precoat remaining unwet with the fluxless solder

Methodology Applied

Scientific EffectWetting: Wetting

Data Source

PatentUS8912453B2Electronic component package

Publication Date: 2014.12.16 MITSUBISHI ELECTRIC CORP

AI summary

An electronic component package includes a circuit board which has a mounting surface that does not show wettability for fluxless solder and on which a semiconductor element is mounted, a soldering pattern that shows wettability for the fluxless solder and is formed to surround an area on which the semiconductor element is mounted, a lid that has a shape such that a cavity is formed between the lid and the circuit board, a bonding surface to the soldering pattern is formed in a ring shape, and does not show wettability for the fluxless solder, a solder bonded part that is formed by heating a solder precoat formed of the fluxless solder on a bonding surface of the lid, and a ventilation hole that is formed by providing a bonding surface of the lid exposed in a discontinuous part of the solder precoat after the solder bonded part is formed.