Titanium Copper Foil Sn Plating for Etching and Adhesion
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Solution Overview
Problem
Conventional titanium copper foils for autofocus camera modules face challenges in etching processability, adhesive strength, and resistance to discoloration and chemical solutions, leading to defects and reduced yield.
Innovation Solution
A titanium copper foil with a Sn plated layer on its surface, having a thickness of 0.01 to 2.0 μm, is developed to enhance etching processability and adhesive strength, while improving resistance to acid or alkaline solutions, thereby preventing discoloration and residue formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a titanium copper foil is used as a spring material for AFMs, then cost reduction is achieved, but etching processability and adhesive strength are insufficient
Solution Approach 1:
The patent applies composite material structure by combining titanium copper alloy (base material) with Sn plated layer (surface coating). This composite structure leverages the cost advantage and mechanical properties of titanium copper while adding the etching processability and adhesive strength of Sn plating, thereby resolving the contradiction between cost reduction and manufacturing performance.
Solution Approach 2:
The patent applies local quality principle by applying Sn plating only on the surface of the titanium copper foil where etching and adhesion are critical, while the bulk material maintains the cost-effective titanium copper composition. This localized treatment optimizes the specific surface properties without compromising the overall cost advantage.
2Strength
If conventional titanium copper foil is used, then cost is reduced, but adhesive strength to solder is insufficient
Solution Approach 1:
The Sn plated layer forms a composite structure that provides superior adhesive strength to solder compared to bare titanium copper. The Sn layer acts as an intermediate bonding layer that enhances wetting and adhesion properties, while the underlying titanium copper maintains cost effectiveness.
Solution Approach 2:
The Sn plated layer serves as an intermediary between the titanium copper substrate and the solder. It mediates the bonding interface, providing better wetting characteristics and adhesive strength, thereby resolving the adhesion issue without requiring expensive alternative base materials.
3Reliability
If conventional titanium copper foil is used, then cost is reduced, but resistance to discoloration and chemical solutions is insufficient
Solution Approach 1:
The Sn plated layer provides a protective barrier that enhances resistance to discoloration and chemical corrosion. This protective coating is applied over the cost-effective titanium copper substrate, creating a composite structure that combines economic advantage with improved environmental resistance.
Solution Approach 2:
The Sn plating converts the potential harm of titanium copper oxidation and chemical reactivity into a benefit by providing a sacrificial protective layer. The Sn layer reacts with corrosive environments first, protecting the underlying titanium copper and preventing discoloration, thereby turning the material's reactivity into a protective mechanism.
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 Sn plated layer ensures improved etching processability and adhesive strength, preventing discoloration and residue formation, making the titanium copper foil suitable for use as a spring material in autofocus camera modules with enhanced chemical resistance.
Implementation Method 1
improving resistance to acid or alkaline solutions, thereby preventing discoloration and residue formation
Implementation Method 2
having a solder adhesive strength of 0.5 N or more
Data Source
AI summary
The present invention provides a titanium copper foil having improved adhesion to solder and higher resistance to discoloration due to a high temperature and high humidity environment, an acid solution or an alkaline solution, and as well as having improved etching processability. The present invention provides a titanium copper foil comprising a base metal, the base metal having a composition containing Ti of from 1.5 to 5.0% by mass, the balance being copper and inevitable impurities, and having a thickness of from 0.018 to 0.1 mm, wherein the titanium copper foil has an Sn plated layer on a surface of the base metal, and has an adhesive strength of 0.5 N or more as measured by a solder adhesive strength test according to the definition in the specification.