Acidic Etchant Composition for Multilayered Film Precision
Solution Overview
Problem
Conventional etchants for copper and titanium multilayered films face issues such as instability, gas and heat generation, pH-related problems, and limited etching precision, leading to reduced productivity and environmental concerns.
Innovation Solution
An etchant composition comprising a copper ion source, an organic acid ion with carboxyl groups, a fluoride ion source, an etching controller, a surface oxidizing power enhancer, and a surfactant, which does not include hydrogen peroxide or persulfate, allowing for stable etching with adjustable etching rates and reduced residue formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an ammonia alkaline etchant containing copper ion and ammonia is used for etching, then copper etching can be achieved, but a large amount of ammonia is volatilized causing etching rate variation and degraded working environment
Solution Approach 1:
The patent changes the pH parameter from alkaline (ammonia-based) to acidic (oxalic acid-based), fundamentally altering the etchant's chemical properties. This parameter change eliminates ammonia volatilization while maintaining effective copper etching through the acidic etching mechanism, directly resolving the contradiction between etching performance and harmful emissions.
Solution Approach 2:
The patent converts the harmful alkaline ammonia environment into a beneficial acidic environment using oxalic acid. The acidic conditions not only eliminate ammonia volatilization but also provide stable etching performance and prevent resist dissolution, transforming a harmful etching system into a beneficial one.
2Reliability
If hydrogen peroxide or persulfate is used as main component in etchant, then copper etching can be achieved, but productivity is reduced and waste liquid amount increases due to instability and rapid decomposition
Solution Approach 1:
The patent replaces unstable, rapidly decomposing oxidants (hydrogen peroxide, persulfate) with a stable, long-lasting acidic etching system based on oxalic acid and copper ions. This substitution eliminates the need for frequent etchant replacement and waste disposal, significantly improving productivity while maintaining effective copper etching.
3Speed
If high pH etchant is used for etching, then copper etching rate can be maintained, but resist is dissolved causing pattern distortion
Solution Approach 1:
The patent changes the pH parameter from high (alkaline) to low (acidic), fundamentally altering the etching mechanism. The acidic environment maintains effective copper etching rates while being gentle enough to preserve the resist material, thus achieving both high etching speed and high pattern accuracy without the trade-off present in alkaline systems.
4Reliability
If conventional etchants are used for multilayered film etching, then copper etching can be achieved, but etching precision is limited and residue is generated
Solution Approach 1:
The patent applies local quality by using oxalic acid specifically tailored for copper etching in multilayered films. The acidic etching mechanism provides selective and precise removal of copper layers while leaving other materials intact, achieving high etching precision and eliminating residue generation that plagues conventional etchants.
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 composition provides stable and precise etching with reduced waste, improved etching rate control, and enhanced environmental sustainability, while preventing gas and heat generation, and maintaining low pH to avoid resist lifting.
Implementation Method 1
an etchant composition including: (A) a copper ion source; (B) a source of an organic acid ion having one or more carboxyl groups in a molecule
Implementation Method 2
a surface oxidizing power enhancer
Implementation Method 3
a fluoride ion source
Implementation Method 4
a source of an organic acid ion having one or more carboxyl groups in a molecule
Implementation Method 5
a surfactant, as a second additive
Implementation Method 6
an etching controller
Data Source
AI summary
Embodiments provide an etchant composition including (A) a copper ion source, (B) a source of an organic acid ion having one or more carboxyl groups in a molecule, (C) a fluoride ion source, (D) an etching controller, a surface oxidizing power enhancer or a combination thereof as a first additive, and (E) a surfactant as a second additive; a method for etching a multilayered film; and a method for preparing a display device.