Acidic Post-Plating Washing for Sn Compound Contamination Control

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Solution Overview

Problem

Conventional washing methods with water or warm water are insufficient to prevent the accumulation of compound contaminations derived from Sn or Sn alloy on substrates and conveyance tools after plating, leading to potential plating extension and increased maintenance costs.

Innovation Solution

A treatment method involving immediate washing with an acidic solution having a pH of 5 or lower, containing acids, salts, complexing agents, and surfactants, effectively prevents the accumulation of compound contaminations on substrates and conveyance tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If general washing with water or warm water is used after plating with Sn or Sn alloy, then the washing process is simple and cost-effective, but compound contaminations derived from Sn or Sn alloy accumulate on substrates and conveyance tools

Engineering Contradiction:
Improvewashing process simplicityVSAvoidcompound contamination accumulation
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical parameter of the washing solution from neutral (water) to acidic (pH 5 or lower), which fundamentally alters the washing mechanism to effectively remove Sn-based compound contaminations that water cannot eliminate

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful acidic nature of the solution into a beneficial cleaning mechanism, where the acidity specifically targets and dissolves Sn oxide and other compound contaminations, turning a potentially problematic chemical property into the solution's primary cleaning advantage

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Object-generated harmful factors

If members are frequently replaced or special washing methods are adopted to prevent contamination accumulation, then contamination is effectively controlled, but work efficiency is reduced and costs increase

Engineering Contradiction:
Improvecontamination controlVSAvoidwork efficiency
Core Design Contradiction:
Object-generated harmful factorsVSProductivity

Solution Approach 1:

The washing system is designed to automatically perform the acidic washing process as part of the standard post-plating procedure, eliminating the need for manual intervention, frequent member replacement, or specialized cleaning operations, thereby maintaining high productivity while ensuring effective contamination control

Inventive Principle:
Principle #25Self-service

3Device complexity

If general washing methods are used, then operational complexity is low, but plating extension to plating apparatus and conveyance tools occurs

Engineering Contradiction:
Improvewashing system complexityVSAvoidplating extension
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The acidic washing is performed immediately after plating as a preliminary protective action, preventing plating extension from occurring in the first place by removing freshly deposited Sn compounds before they can spread to other apparatus components

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

The method significantly reduces the need for frequent replacement of plating apparatus components and special washing methods, maintaining work efficiency and minimizing costs by effectively preventing contamination accumulation.

Implementation Method 1

washing at least one of members used in a series of plating treatment steps with an acidic solution immediately after the plating

Methodology Applied
Scientific EffectChemical dissolution:

Implementation Method 2

the acidic solution contains at least one kind selected from acids and salts thereof and has a pH of 5 or lower

Methodology Applied
Scientific EffectSurfactant action: Surfactant

Data Source

PatentUS12448690B2Treatment method after plating with Sn or Sn alloy
Publication Date: 2025.10.21 ISHIHARA CHEM CO LTD

AI summary

A treatment method is for preventing compound contaminations derived from Sn or an Sn alloy, which have precipitated on members, such as a substrate and a conveyance tool, from accumulating after plating with Sn or the Sn alloy. The method includes washing at least one of the members used in a series of plating treatment steps with an acidic solution immediately after the plating with Sn or the Sn alloy. The acidic solution contains at least one acid or salt thereof having a pH of 5 or lower.