Neutral Tin Plating Solution for Electronic Components

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Solution Overview

Problem

Miniaturization of electronic components leads to coupling issues during barrel and high-speed rotary plating, and existing neutral tin plating solutions fail to prevent foaming effectively, affecting manufacturability and plating quality.

Innovation Solution

A neutral tin plating solution comprising stannous ions, alkane or alkanol sulfonic acids, a complexing agent like gluconic acid, and a diamine with a polyoxyalkylene chain, maintaining a pH between 4 and 8, which prevents coupling and minimizes foaming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If barrel plating or high-speed rotary plating is performed on miniaturized electronic components, then plating coverage is improved, but coupling between components occurs

Engineering Contradiction:

Improveplating coverageVSAvoidcomponent separation

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

A dummy ball made of soft material (resin or rubber) is introduced as an intermediary between electronic components during plating. This soft dummy ball prevents direct contact and coupling between components while still allowing adequate plating solution circulation for good plating coverage. The soft material deforms to accommodate components without causing damage or coupling.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the material parameter of the dummy ball from hard (metal) to soft (resin or rubber). This parameter change allows the dummy ball to deform and adapt to the spacing between miniaturized components, preventing coupling while maintaining plating effectiveness. The softness parameter is key to resolving the contradiction.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If conventional plating solutions are used, then plating process is simple, but foaming occurs at solution surface

Engineering Contradiction:

Improveprocess simplicityVSAvoidfoaming

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention extracts and removes the foaming problem by using a plating solution formulation that inherently suppresses foam generation. The specific combination of sulfonic acid and complexing agent creates a solution that maintains plating effectiveness while eliminating the harmful foaming effect that complicates the process.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If strong acid plating solution (pH ≤ 1) is used, then coupling prevention is improved, but ceramic components are damaged

Engineering Contradiction:

Improvecoupling preventionVSAvoidceramic damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the pH parameter of the plating solution from strongly acidic (pH ≤ 1) to weakly acidic (pH 2-4). This parameter change prevents ceramic component damage while still maintaining adequate coupling prevention through the combined effect of the softened dummy ball and the modified solution chemistry.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite approach combining a soft dummy ball material (resin or rubber) with a weakly acidic plating solution. This composite solution strategy achieves coupling prevention without the harsh conditions that damage ceramic components, resolving the contradiction between protection and damage prevention.

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

The solution effectively prevents coupling of electronic components and reduces foaming, enhancing manufacturability and plating quality by stabilizing the plating process and maintaining the integrity of ceramic components.

Implementation Method 1

a diamine that includes a polyoxyalkylene chain

Methodology Applied

Scientific EffectSteric hindrance:

Implementation Method 2

stannous ions from a tin salt of alkane sulfonic acids or alkanol sulfonic acids

Methodology Applied

Scientific EffectElectrostatic repulsion: Ion Repulsion/Attraction

Implementation Method 3

a complexing agent selected from gluconic acid, citric acid, malonic acid, succinic acid, tartaric acid, or a salt thereof

Methodology Applied

Scientific EffectComplexation:

Implementation Method 4

barrel plating or high-speed rotary plating on electronic components

Methodology Applied

Scientific EffectElectroplating: Electroplating

Implementation Method 5

carries out barrel plating or high-speed rotary plating using a tin plating solution that includes (A) stannous ions

Methodology Applied

Scientific EffectElectrochemical reduction: Redox Reactions

Implementation Method 6

a diamine that includes a polyoxyalkylene chain

Methodology Applied

Scientific EffectSurface tension reduction: Surfactant

Data Source

PatentEP3321396B1Barrel plating or high-speed rotary plating using a neutral tin plating solution

Publication Date: 2021.07.07 DUPONT ELECTRONIC MATERIALS INT LLC

AI summary

A barrel plating or high-speed rotary plating method for electronic components, and a neutral tin plating solution used therein. A plating solution that includes (A) stannous ions, (B) an acid or a salt, (C) a complexing agent, and (D) a diamine that has a polyoxyalkylene chain, and that has a pH in a range between 4 and 8 is used. The use of this neutral tin plating solution prevents the electronic components from coupling together during the barrel plating, enabling an improvement in manufacturability in barrel plating.