Contact Pad Segregation Suppression for Corrosion Resistance

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Solution Overview

Problem

Metal alloys used in electronic components are susceptible to pitting corrosion, which can be exacerbated by artificial passivation methods that obstruct electrical contact and potentially induce galvanic corrosion, while conventional methods to reduce corrosion either weaken electrical contacts or increase the risk of corrosion.

Innovation Solution

A method involving the formation of a contact pad with a self-segregating composition and a segregation suppression structure featuring nucleation inducing topography features to perturb chemical segregation, thereby reducing pitting corrosion by refining the microstructure and preventing galvanic coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If artificial passivation is applied to reduce pitting corrosion, then corrosion resistance is improved, but electrical contact capability deteriorates

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidelectrical contact capability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The contact pad is divided into multiple crystallites with different orientations, creating internal boundaries that segment the material structure. This segmentation prevents uniform chemical segregation and reduces galvanic coupling while maintaining electrical conductivity through the distributed crystallite structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The contact pad employs a self-segregating composition where different regions have different crystallographic orientations and local compositions. This local variation in properties prevents uniform corrosion pathways while maintaining overall electrical functionality through the heterogeneous structure.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If dry etching is used to remove artificial passivation for electrical contact, then electrical contact capability is improved, but pitting corrosion risk increases

Engineering Contradiction:

Improveelectrical contact capabilityVSAvoidpitting corrosion risk

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The contact pad is pre-formed with a self-segregating composition and controlled crystallite structure before electrical contact is established. This preliminary structuring ensures corrosion resistance is built-in from the start, eliminating the need for subsequent passivation removal and avoiding the associated corrosion risks.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If bonding parameters are adapted for bonding through artificial passivation, then electrical contact capability is improved, but contact strength deteriorates

Engineering Contradiction:

Improveelectrical contact capabilityVSAvoidcontact strength

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The contact pad's segmented crystallite structure provides multiple bonding interfaces and load distribution pathways, enhancing overall contact strength while maintaining electrical capability through the distributed conductive network.

Inventive Principle:

Principle #1Segmentation

4Reliability

If artificial passivation including metal is used to reduce corrosion, then corrosion resistance is improved, but galvanic corrosion is induced

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidgalvanic corrosion

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The contact pad uses a self-segregating composition of the same metal alloy throughout, creating a homogeneous material system that eliminates galvanic potential differences. The uniform composition prevents galvanic corrosion while the controlled crystallite structure provides corrosion resistance without requiring additional metal passivation layers.

Inventive Principle:

Principle #33Homogeneity

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 effectively reduces pitting corrosion and galvanic corrosion, ensuring stable electrical contacts by spatially limiting compositional variations and preventing galvanic interactions, thus enhancing the durability and reliability of electronic components.

Implementation Method 1

perturbing a chemical segregation of the self-segregating composition by crystallographic interfaces of the contact pad defined by the nucleation inducing topography features

Methodology Applied

Scientific EffectChemical segregation: Diffusion

Implementation Method 2

the segregation suppression structure includes more nucleation inducing topography features than the at least one electrically conductive contact region

Methodology Applied

Scientific EffectNucleation: Nucleation

Data Source

PatentUS9966348B2Method for processing an electronic component and an electronic component

Publication Date: 2018.05.08 INFINEON TECHNOLOGIES AG

AI summary

According to various embodiments an electronic component includes: at least one electrically conductive contact region; a contact pad including a self-segregating composition disposed over the at least one electrically conductive contact region; a segregation suppression structure disposed between the contact pad and the at least one electrically conductive contact region, wherein the segregation suppression structure includes more nucleation inducing topography features than the at least one electrically conductive contact region for perturbing a chemical segregation of the self-segregating composition by crystallographic interfaces of the contact pad defined by the nucleation inducing topography features.