Mo-Nb-Ta Sputtering Target for Touch Screen Etching
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Solution Overview
Problem
Existing touch screen devices using molybdenum-based layers suffer from corrosion issues and reliability problems, particularly when exposed to etchants, leading to low performance and manufacturing challenges.
Innovation Solution
A sputtering target comprising 88-97 atomic percent molybdenum, 2-8 atomic percent niobium, and 0.5-5 atomic percent tantalum is used to create a molybdenum alloy layer with improved corrosion resistance and adhesion, allowing for high reliability and uniform electrical conductivity in touch screen devices, even when etched with various etchants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a molybdenum-based layer is used in touch screen devices, then electrical conductivity is achieved, but corrosion resistance deteriorates leading to reliability problems
Solution Approach 1:
The patent applies composite materials by creating a multi-layer structure consisting of a molybdenum alloy layer (88-97 at% Mo, 2-8 at% Nb, 0.5-5 at% Ta) combined with an oxide layer. This composite structure provides both the electrical conductivity needed for touch screen functionality and the corrosion resistance required for reliability, as the oxide layer protects the underlying molybdenum alloy from corrosive etchants while the alloy maintains conductive properties.
2Manufacturing precision
If a molybdenum alloy layer is etched with etchants, then patterning is achieved, but undercutting occurs where the first layer is carved out from under the second layer
Solution Approach 1:
The patent applies parameter changes by carefully controlling the composition parameters of the molybdenum alloy layer (specifically 88-97 at% Mo, 2-8 at% Nb, 0.5-5 at% Ta) and the etching process parameters. This optimization ensures that the etch rate of the molybdenum alloy layer matches the etch rate of overlying layers, preventing undercutting and maintaining layer integrity during the patterning process.
3Reliability
If molybdenum alloy composition is optimized for corrosion resistance, then reliability improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by creating distinct layers with specific compositions optimized for their particular functions. The molybdenum alloy layer has a specific composition range (88-97 at% Mo, 2-8 at% Nb, 0.5-5 at% Ta) optimized for corrosion resistance and conductivity, while the oxide layer provides protective qualities. Each layer's composition is locally optimized for its specific role, simplifying the overall manufacturing approach compared to attempting to achieve all properties in a single homogeneous material.
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 molybdenum alloy layer provides enhanced corrosion resistance, reliability, and uniform electrical conductivity, preventing undercutting during etching and ensuring high performance and manufacturing flexibility in touch screen devices.
Implementation Method 1
Sputtering targets and devices including Mo, Nb, and Ta, and methods
Data Source
AI summary
Sputtering targets including molybdenum, niobium and tantalum are found to be useful for sputtering films for electronic devices. Sputtering targets with about 88 to 97 weight percent molybdenum show improved performance, particularly with respect to etching, such as when simultaneously etching an alloy layer including the Mo, Nb, and Ta, and a metal layer (e.g., an aluminum layer). The targets are particularly useful in manufacturing touch screen devices.