Titanium Etching Solution Stability and Undercut Control
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Solution Overview
Problem
Current wet etching solutions for titanium-series metals face issues with stability, etching rate, uniformity, and safety due to hydrofluoric acid, leading to corrosion, safety hazards, and undercut problems in advanced packaging processes.
Innovation Solution
An etching solution comprising hydrogen peroxide as an oxidant, combined with stabilizers such as inorganic phosphate, organophosphorus acids, and organic poly-carboxylic acids, which control pH and prevent excessive decomposition, enhancing stability and etching uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrofluoric acid-based etching solution is used, then etching rate is improved, but corrosion of silicon substrate, glass substrate, and aluminum wiring occurs
Solution Approach 1:
The patent removes hydrofluoric acid from the etching solution composition entirely, extracting the harmful component while retaining the etching function through alternative chemistry (ammonium persulfate-based system). This resolves the contradiction by eliminating the source of corrosion while maintaining etching capability.
Solution Approach 2:
The patent introduces ammonium persulfate as an intermediary oxidizing agent that enables titanium etching without requiring hydrofluoric acid. This mediator achieves the etching function through a different chemical mechanism (oxidation rather than fluorination), thereby avoiding the harmful corrosion effects.
2Productivity
If hydrofluoric acid-containing etching solution is used, then etching capability is improved, but safety hazards and stability problems occur
Solution Approach 1:
The patent extracts hydrofluoric acid from the etching solution, eliminating the safety hazards associated with handling and storing this dangerous chemical. The alternative ammonium persulfate-based system provides comparable etching capability without the severe safety risks.
Solution Approach 2:
The patent employs a etching solution system that can be easily prepared and replaced without requiring complex safety infrastructure. The ammonium persulfate-based solution is inherently safer and more stable, allowing for simpler operational procedures and reduced safety management overhead.
3Productivity
If hydrogen peroxide is used in alkaline environment, then titanium etching is achieved, but hydrogen peroxide decomposes rapidly causing instability
Solution Approach 1:
The patent changes the pH parameter from alkaline to acidic range (pH 1-6), which fundamentally alters the stability characteristics of hydrogen peroxide. In this acidic environment, hydrogen peroxide remains stable and does not undergo rapid decomposition, while still maintaining effective titanium etching capability.
Solution Approach 2:
The patent modifies the chemical composition by introducing specific stabilizing agents (organic phosphoric acid and its esters) that further enhance the stability of hydrogen peroxide in the etching solution, preventing unwanted decomposition reactions.
4Productivity
If existing etching solution is used, then etching process is completed, but undercut occurs in seed titanium layer
Solution Approach 1:
The patent modifies the local chemical environment at the etching interface by introducing organic phosphoric acid and its esters, which create a more controlled etching front. This localized chemical modification prevents lateral etching (undercut) while maintaining vertical etching efficiency, thereby improving manufacturing precision.
Solution Approach 2:
The patent creates a composite etching solution system combining ammonium persulfate, organic phosphoric acid, and its esters in specific proportions. This composite composition works synergistically to achieve both complete etching and precise undercut control, resolving the contradiction between productivity and manufacturing precision.
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 solution improves the stability and etching rate of titanium-series metals, reduces corrosion, and maintains uniformity, extending the solution's service life and preventing undercut issues.
Implementation Method 1
an etching solution, wherein a preparation raw material of the etching solution includes at least one oxidant... the oxidant is selected from one of hydrogen peroxide, ammonium persulfate, or potassium persulfate
Implementation Method 2
combined with stabilizers such as inorganic phosphate, organophosphorus acids, and organic poly-carboxylic acids, which control pH and prevent excessive decomposition
Data Source
AI summary
The present disclosure relates to the technical field of etching. More specifically, the present disclosure relates to an etching solution and an application thereof. A preparation raw material of the etching solution includes at least one oxidant, at least one stabilizer, and deionized water. Through the combined action of hydrogen peroxide and stabilizer, the etching solution of the present disclosure has the good stability, the longer service life, the faster etching rate and the better stability of the etching rate, and the etching solution of the present disclosure has a good etching effect on a titanium-series metal.