Ammonium Persulfate Etching Composition for Copper Pattern Control
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Solution Overview
Problem
Existing copper etching compositions that use strong oxidizers like hydrogen peroxide or iron (III) hydroxide effectively damage pre-existing patterns and have uncontrolled etch rates, leading to copper layers being etched into shapes different from their designed forms, which complicates the manufacturing of display substrates with high-resolution metal patterns.
Innovation Solution
An etching composition comprising ammonium persulfate, organic acid, chelating agent, fluoride compound, chloride compound, and azole-based compound, with water as the main solvent, which etches copper layers without relying on strong oxidizers, thereby improving etching process stability and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If strong oxidizers like hydrogen peroxide or iron (III) hydroxide are used as main etching agents, then copper layer etching effectiveness is improved, but pre-existing patterns are damaged and etch rate control becomes difficult
Solution Approach 1:
The patent changes the chemical parameters of the etching composition by replacing strong oxidizers with ammonium persulfate as the main etching agent. This substitution fundamentally alters the etching mechanism while maintaining effectiveness on copper layers. The composition includes ammonium persulfate (0.1-25 wt%), organic acid (0.1-25 wt%), chelating agent (0.01-5 wt%), fluoride compound (0.01-5 wt%), chloride compound (0.01-5 wt%), and azole-based compound (0.01-2 wt%), creating a balanced chemical environment that etches copper effectively without damaging pre-existing patterns.
Solution Approach 2:
The patent introduces multiple intermediary substances that mediate the etching process. The chelating agent complexes with copper ions to control etching rate, the azole-based compound acts as a corrosion inhibitor to protect pre-existing patterns, and the fluoride and chloride compounds modify the etching environment. These intermediaries work together to enable effective copper etching while preserving pattern integrity and providing controllable etch rates.
2Speed
If strong oxidizers are used to etch copper layers, then etching speed is improved, but etching process stability deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by using ammonium persulfate instead of strong oxidizers like hydrogen peroxide. This parameter change maintains fast etching speed while improving process stability. The controlled release of active species from ammonium persulfate provides consistent etching performance, and the presence of stabilizing agents like chelating agents and azole-based compounds further enhances etching process stability by controlling copper ion concentration and preventing unwanted side reactions.
3Productivity
If strong oxidizers are used for copper etching, then copper layer removal efficiency is improved, but contamination resistance deteriorates
Solution Approach 1:
The patent introduces intermediary substances that protect against contamination while maintaining etching efficiency. The chelating agent binds copper ions to prevent their deposition as contaminants, the azole-based compound forms protective films on metal surfaces to prevent oxidation and contamination, and the fluoride compound helps remove organic contaminants. These intermediaries work synergistically to enable efficient copper removal while resisting contamination.
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 composition effectively forms stable metal patterns with controlled etching rates and dimensions, maintaining etching ability over time and resisting contamination, thus enhancing manufacturing reliability and productivity in display substrate production.
Implementation Method 1
an etching composition includes about 0.1% by weight to about 25% by weight of ammonium persulfate, about 0.1% by weight to about 25% by weight of an organic acid, about 0.01% by weight to about 5% by weight of a chelating agent, about 0.01% by weight to about 5% by weight of a fluoride compound, about 0.01% by weight to about 5% by weight of a chloride compound, about 0.01% by weight to about 2% by weight of an azole-based compound, and a remainder of water
Implementation Method 2
about 0.01% by weight to about 5% by weight of a chelating agent
Implementation Method 3
about 0.01% by weight to about 2% by weight of an azole-based compound
Data Source
AI summary
An etching composition, a method of forming a metal pattern using the etching composition, and a method of manufacturing a display substrate are disclosed. The etching composition includes about 0.1% by weight to about 25% by weight of ammonium persulfate, about 0.1% by weight to about 25% by weight of an organic acid, about 0.01% by weight to about 5% by weight of a chelating agent, about 0.01% by weight to about 5% by weight of a fluoride compound, about 0.01% by weight to about 5% by weight of a chloride compound, about 0.01% by weight to about 2% by weight of an azole-based compound and a remainder of water. Thus, a copper layer may be stably etched to improve a reliability of manufacturing the metal pattern and the display substrate.