Palladium Plated Copper Circuitry Reflectivity Reduction
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Solution Overview
Problem
Copper and copper alloy circuitry in electronic components, such as image display devices and touch screens, exhibit high optical reflectivity due to their shiny surfaces, leading to visibility issues and mechanical instability of surface oxide layers, which are brittle and have low adhesion, increasing electrical resistivity and susceptibility to corrosion.
Innovation Solution
A method involving the deposition of a thin palladium or palladium alloy layer onto copper or copper alloy circuitry using immersion-type plating, which reduces optical reflectivity while maintaining mechanical stability and low electrical resistivity, by selectively depositing the palladium layer either before or after the circuitry pattern is formed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper or copper alloy circuitry is used due to high electrical conductivity, then electrical conductivity is improved, but optical reflectivity increases causing visibility issues
Solution Approach 1:
A thin layer of palladium or palladium alloy is deposited onto the copper or copper alloy circuitry to serve as an intermediary layer. This palladium layer reduces the optical reflectivity and visibility of the copper circuitry while maintaining the underlying copper's high electrical conductivity. The palladium acts as a mediator that modifies the optical properties without compromising the electrical performance.
2Object-affected harmful factors
If chemical oxidation treatment is applied to reduce optical reflectivity, then optical reflectivity is reduced, but mechanical stability deteriorates due to brittle oxide layers with low adhesion
Solution Approach 1:
Instead of forming brittle oxide layers through chemical oxidation, a thin layer of palladium or palladium alloy is deposited as an intermediary protective layer. This metallurgical coating provides both optical masking and mechanical stability, eliminating the adhesion and brittleness problems associated with chemical oxidation layers.
3Object-affected harmful factors
If chemical oxidation treatment is applied to reduce optical reflectivity, then optical reflectivity is reduced, but electrical resistivity increases due to copper consumption
Solution Approach 1:
The palladium or palladium alloy layer serves as an intermediary that reduces optical reflectivity without consuming the copper material. Unlike chemical oxidation which converts conductive copper into non-conductive oxides, the palladium deposition process maintains the copper's electrical conductivity while providing the desired optical masking effect.
4Reliability
If copper surface is left shiny to maintain low electrical resistivity, then electrical resistivity is reduced, but optical visibility increases
Solution Approach 1:
A thin layer of palladium or palladium alloy is deposited onto the copper circuitry to serve as an intermediary layer that masks the optical visibility while preserving the electrical conductivity. The palladium layer is thin enough to not significantly increase electrical resistivity but sufficient to reduce the shiny appearance and visibility of the copper circuitry.
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 the optical reflectivity of copper and copper alloy surfaces, enhancing mechanical stability and corrosion resistance with minimal consumption of the copper or copper alloy, resulting in a durable and low-resistivity circuitry suitable for electronic components.
Implementation Method 1
depositing a palladium or palladium alloy layer onto said copper or copper alloy by immersion-type plating
Data Source
AI summary
The present invention relates to a method for reducing the optical reflectivity of a copper and copper alloy circuitry wherein a thin palladium or palladium alloy layer is deposited by immersion-type plating onto said copper or copper alloy. Thereby, a dull greyish or greyish black or black layer is obtained and the optical reflectivity of said copper or copper alloy circuitry is reduced. The method according to the present invention is particularly suitable in the manufacture of image display devices, touch screen devices and related electronic components.