Silane-Modified Etching Composition for Selective Nitride Removal
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Solution Overview
Problem
Current etching processes for semiconductor manufacturing face challenges in selectively removing nitride films while minimizing oxide film etching rates, often resulting in defects and particle generation due to low etch selectivity and the use of corrosive acids like phosphoric acid.
Innovation Solution
A high-selectivity etching composition comprising a first inorganic acid, a silane inorganic acid salt, and a solvent, which includes a first additive with a specific chemical structure and a second additive produced by reacting a silane compound with an inorganic acid, allowing for controlled etching of nitride films relative to oxide films at temperatures between 50°C to 300°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If phosphoric acid is used for wet etching of nitride film, then etching capability is improved, but etch selectivity between nitride film and oxide film decreases
Solution Approach 1:
The patent modifies the chemical composition parameters of the etching solution by combining phosphoric acid with hydrofluoric acid and nitric acid in specific proportions. This parameter change enables simultaneous achievement of high etching rate for nitride film and high selectivity against oxide film, resolving the contradiction between etching speed and selectivity
Solution Approach 2:
The patent creates a composite etching solution comprising multiple acids (phosphoric acid, hydrofluoric acid, nitric acid) and additives (silicic acid, surfactants) working together. This composite formulation achieves synergistic effects where the combination provides both high etching capability for nitride and high selectivity, overcoming the limitations of single-acid systems
2Productivity
If phosphoric acid is used for removing nitride film, then nitride film removal efficiency is improved, but oxide film damage increases
Solution Approach 1:
The patent introduces hydrofluoric acid and nitric acid as intermediary substances that modify the etching mechanism. These intermediaries enable selective attack on nitride film while protecting oxide film from damage, allowing efficient nitride removal without the harmful effects of pure phosphoric acid on oxide layers
3Stability of the object's composition
If deionized water is added to prevent etch rate decrease, then etch rate stability is improved, but particle generation increases
Solution Approach 1:
The patent replaces deionized water with a specially formulated aqueous solution containing volatile organic compounds and surfactants. This substitute provides the necessary stability for etch rate control while being easily removable after etching, preventing particle generation on the substrate surface
4Speed
If phosphoric acid concentration is increased to improve etching speed, then etching rate increases, but handling difficulty and corrosiveness increase
Solution Approach 1:
The patent optimizes the concentration parameters of phosphoric acid and other components to achieve the desired etching rate while maintaining manageable corrosiveness. By carefully balancing the concentrations of multiple acids and additives, the solution provides high etching performance with improved safety and ease of handling compared to concentrated phosphoric acid alone
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 achieves high etch selectivity for nitride films over oxide films, preventing particle generation and maintaining device characteristics by minimizing oxide film etching, thus enhancing the reliability and efficiency of semiconductor device production processes.
Implementation Method 1
In a wet etching process for removing a nitride film, a mixture of phosphoric acid and deionized water is generally used
Implementation Method 2
technologies for removing nitride films using a composition for etching employing phosphoric acid (H3PO4) together with hydrofluoric acid (HF) or nitric acid (HNO3)
Data Source
AI summary
The present invention relates to a composition for etching, comprising a first inorganic acid, a first additive represented by Chemical Formula 1, and a solvent.The composition for etching is a high-selectivity composition that can selectively remove a nitride film while minimizing the etch rate of an oxide film, and which does not have problems such as particle generation, which adversely affect the device characteristics.