Etching Composition for Silver Thin Films
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Solution Overview
Problem
Existing etching compositions for display devices face challenges in effectively etching silver-containing thin films and metal oxide layers without causing excessive etching residue, CD-skew, or reductive precipitation of silver particles, which can lead to manufacturing defects and reduced reliability.
Innovation Solution
An etching composition comprising specific ratios of inorganic acid, carboxylic acid, sulfonic acid, glycol, nitrogen-containing dicarbonyl, and sulfate compounds, along with water, is used to etch silver-containing and metal oxide thin films, preventing excessive etching residue and maintaining stable etching rates, thereby minimizing defects and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching compositions are used to etch silver-containing thin films and metal oxide layers, then etching can be performed, but excessive etching residue, CD-skew, and reductive precipitation of silver particles occur
Solution Approach 1:
The patent changes the chemical parameters of the etching composition by specifying precise concentration ranges for multiple components: inorganic acid (8.1-9.9 wt%), carboxylic acid (40-55 wt%), sulfonic acid (1-4.9 wt%), glycol (1-5 wt%), nitrogen-containing dicarbonyl compound (2-10 wt%), and sulfate compound (1-15 wt%). This parameter optimization resolves the contradiction by achieving effective etching while minimizing harmful residues and precipitation through balanced chemical ratios.
Solution Approach 2:
The patent employs a composite etching composition combining six different chemical compounds working synergistically. The inorganic acid provides primary etching capability, carboxylic acid modulates etching rate, sulfonic acid enhances wetting, glycol controls viscosity, nitrogen-containing dicarbonyl compound prevents precipitation, and sulfate compound regulates conductivity. This composite approach enables precise control over etching behavior to eliminate harmful effects.
2Productivity
If etching composition is optimized for etching rate, then productivity increases, but etching residue and CD-skew increase
Solution Approach 1:
The patent achieves balanced etching performance by optimizing the concentration parameters of multiple components simultaneously. The specific ranges provided (e.g., carboxylic acid at 40-55 wt% as the major component, inorganic acid at 8.1-9.9 wt%) create a synergistic effect that maintains high etching rate while controlling CD-skew and residue through the combined action of all components at their optimal concentrations.
Solution Approach 2:
The patent introduces intermediate substances that mediate between the aggressive etching action and the need for precision. The carboxylic acid acts as a rate-modulating intermediary, the sulfonic acid as a wetting intermediary, and the nitrogen-containing dicarbonyl compound as a precipitation-preventing intermediary. These intermediaries enable the system to achieve high productivity without sacrificing manufacturing precision.
3Reliability
If strong etching agents are used to remove metal oxide layers, then etching effectiveness improves, but reductive precipitation of silver particles occurs
Solution Approach 1:
The patent prevents reductive precipitation by carefully controlling the chemical environment parameters. The sulfate compound (1-15 wt%) and nitrogen-containing dicarbonyl compound (2-10 wt%) are specifically included at optimized concentrations to inhibit silver ion reduction. The balanced pH and ionic strength provided by the combination of acids and salts create conditions where silver remains in solution during effective metal oxide etching.
Solution Approach 2:
The nitrogen-containing dicarbonyl compound serves as a key intermediary that prevents direct reduction of silver ions to metallic particles. It acts as a complexing agent that keeps silver ions in solution during the etching process. The sulfate compound also serves as an intermediary by providing controlled ionic strength and preventing unwanted side reactions that could lead to precipitation.
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 etching composition effectively etches multiple layer structures, preventing etching residue and CD-skew, and reducing silver particle precipitation, thus improving manufacturing reliability and reducing defects in display devices.
Implementation Method 1
The etching composition may be capable of etching a silver-containing thin film. The etching composition may be capable of etching a multiple layer structure including a silver-containing thin film and a metal oxide thin film
Implementation Method 2
etching composition, comprising an inorganic acid compound, a carboxylic acid compound, a sulfonic acid compound, a glycol compound, a nitrogen-containing dicarbonyl compound, a sulfate compound and water
Data Source
AI summary
An etching composition includes an inorganic acid compound, a carboxylic acid compound, a sulfonic acid compound, a glycol compound, a nitrogen-containing dicarbonyl compound, a sulfate compound and water.