Ammonium Persulfate Etchant for Copper Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing etching processes for manufacturing LCD devices using copper layers face instability and increased costs due to the decomposition of hydrogen peroxide in the presence of copper ions, leading to heat generation and reduced manufacturing margins.
Innovation Solution
An etchant comprising ammonium persulfate, inorganic acid, acetate salt, fluorine-containing compound, sulfonic acid compound, azole compound, and water is used to simultaneously etch titanium and copper bilayers, avoiding hydrogen peroxide and maintaining etching stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrogen peroxide is used for etching copper layer, then etching capability is improved, but manufacturing stability deteriorates due to decomposition and heat generation
Solution Approach 1:
The patent changes the chemical composition parameters of the etchant by replacing hydrogen peroxide with ammonium persulfate as the primary oxidizing agent. This parameter change eliminates the decomposition issue and heat generation problems while maintaining effective etching capability for copper layers, thus improving manufacturing stability without sacrificing productivity
Solution Approach 2:
The patent uses ammonium persulfate instead of hydrogen peroxide, which is a more stable and cost-effective etching solution. The ammonium persulfate-based etchant does not require expensive stabilizers and provides consistent performance without the instability issues of hydrogen peroxide, effectively replacing a problematic material with a superior alternative
2Reliability
If hydrogen peroxide with stabilizer is used, then manufacturing stability is improved, but manufacturing cost increases
Solution Approach 1:
The patent employs ammonium persulfate as the etching agent, which is inherently stable and does not require expensive stabilizing additives. This substitution eliminates the need for costly stabilizers while maintaining manufacturing stability, thereby reducing overall etching solution costs and improving ease of manufacture
Solution Approach 2:
The patent changes the chemical basis of the etching solution from hydrogen peroxide-based to ammonium persulfate-based. This fundamental parameter change in the etchant composition achieves inherent stability without requiring additional stabilizing agents, thus avoiding the increased manufacturing costs associated with hydrogen peroxide stabilization
3Quantity of substance
If copper layer is etched with hydrogen peroxide, then low resistance is achieved, but heat generation occurs due to disproportionation
Solution Approach 1:
The patent changes the chemical composition of the etching solution by replacing hydrogen peroxide with ammonium persulfate. This parameter change in the oxidizing agent eliminates the disproportionation reaction that causes heat generation, while still achieving effective copper etching to maintain low electrical resistance in the metal lines
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 etchant provides improved etching process margins and stability, reducing manufacturing costs while maintaining a tapered profile and high etching speed, without the need for expensive stabilizers.
Implementation Method 1
an etching solution including hydrogen peroxide or ferric iron may be used for etching a copper layer
Implementation Method 2
hydrogen peroxide may cause disproportionation in the presence of copper ions and iron ions to be decomposed into water and oxygen
Data Source
AI summary
An etchant includes about 0.1 percent by weight to about 30 percent by weight of ammonium persulfate (NH4)2S2O8, about 0.1 percent by weight to about 10 percent by weight of an inorganic acid, about 0.1 percent by weight to about 10 percent by weight of an acetate salt, about 0.01 percent by weight to about 5 percent by weight of a fluorine-containing compound, about 0.01 percent by weight to about 5 percent by weight of a sulfonic acid compound, about 0.01 percent by weight to about 2 percent by weight of an azole compound, and a remainder of water. Accordingly, the etchant may have high stability to maintain etching ability. Thus, manufacturing margins may be improved so that manufacturing costs may be reduced.