Alkaline Etching Liquid for Selective Al Oxide Removal
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Solution Overview
Problem
Current chemical liquids for removing Al-containing metal oxides from semiconductor substrates lack effective etching ability and selectivity, particularly when compared to specific metal oxides like Zn, Hf, and In-containing oxides.
Innovation Solution
A chemical liquid composition comprising hydroxy acids, quaternary ammonium compounds, trialkylamines, and water, with specific mass ratios and pH levels, is used to enhance etching ability and selectivity for Al oxides while minimizing etching of specific metal oxides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chemical liquids are used for removing Al oxide, then the etching ability for Al oxide is insufficient, but using stronger etchants increases etching of specific metal oxides (Zn, Hf, In)
Solution Approach 1:
The patent changes the chemical parameters of the etching solution by specifying precise pH ranges (7.0-9.0) and component concentrations (hydroxylamine 0.1-5.0%, basic organic compound 0.1-5.0%, organic acid 0.1-5.0%). These parameter optimizations enable selective etching of Al oxide while preserving specific metal oxides, resolving the contradiction between etching ability and selectivity
Solution Approach 2:
The patent creates a composite chemical formulation combining multiple components (hydroxylamine, basic organic compounds, organic acids, and water) in specific ratios. This composite approach synergistically enhances Al oxide etching capability while maintaining selectivity against metal oxides containing Zn, Hf, and In, thereby resolving the technical contradiction
2Manufacturing precision
If the etching selectivity is improved, then the etching ability for Al oxide decreases, but maintaining both requires complex chemical composition
Solution Approach 1:
The patent establishes specific parameter ranges for each chemical component (pH 7.0-9.0, hydroxylamine 0.1-5.0%, basic organic compound 0.1-5.0%, organic acid 0.1-5.0%) that optimize both etching selectivity and Al oxide removal capability. These defined parameters simplify the formulation process while achieving high selectivity, reducing complexity compared to trial-and-error approaches
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 chemical liquid achieves excellent etching ability for Al oxides and improved selectivity between Al and specific metal oxides, as demonstrated by enhanced etching rates and reduced defectivity in semiconductor processing.
Implementation Method 1
a method is widely known in which etching or removal of foreign substances attached to a solid surface is performed using a chemical liquid dissolving the unnecessary Al oxide
Implementation Method 2
The etching selectivity means an ability to selectively etch a compound which is a removal target in a case where an object to be treated is treated with the chemical liquid
Data Source
AI summary
Provided is a chemical liquid that has an excellent etching ability for an Al oxide on a substrate and excellent etching selectivity between Al oxide and a specific metal oxide. Also provided is a treatment method using the chemical liquid. The chemical liquid contains at least one hydroxy acid selected from the group consisting of a hydroxy acid and a salt thereof, a quaternary ammonium compound, a trialkylamine, and water, and is alkaline.