Etching Composition for Selective Nitride Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current etching compositions for semiconductor manufacturing, such as those using phosphoric acid, face challenges in selectively removing nitride films while minimizing oxide film etch rates and preventing particle generation, which can lead to wafer defects due to varying deionized water amounts and increased oxide film etch rates with hydrofluoric or nitric acid mixtures.
Innovation Solution
An etching composition comprising phosphoric acid and a compound represented by Formula 1, which includes a silicontriol with a bulky pyridine group, is used to selectively etch silicon nitride films with a high selectivity ratio to silicon oxide films, minimizing oxide film etch rates and preventing particle formation through steric hindrance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phosphoric acid and deionized water are used to remove silicon nitride film, then the nitride film can be etched, but particles are generated and etching selectivity changes due to minute changes in deionized water amount
Solution Approach 1:
The patent changes the chemical composition parameters by replacing deionized water with a specific organic compound (alcohol or ether) having controlled molecular structure and properties. This parameter change stabilizes the etching solution composition, preventing particle generation while maintaining consistent etching selectivity between nitride and oxide films.
Solution Approach 2:
The patent replaces the unstable deionized water component with a stable organic solvent that can be precisely formulated and controlled. This substitution creates a more reliable etching composition that maintains consistent performance without the sensitivity to minor composition changes that characterizes deionized water-based solutions.
2Productivity
If hydrofluoric acid or nitric acid is added to phosphoric acid to remove nitride film, then etching capability is improved, but oxide film etch rate increases and etching selectivity decreases
Solution Approach 1:
The patent applies local quality by using an organic compound that specifically targets silicon nitride for etching while leaving silicon oxide relatively unaffected. The organic solvent creates a chemically selective environment that enhances nitride removal kinetics without proportionally increasing oxide etch rate, thereby maintaining high selectivity ratio.
Solution Approach 2:
The patent creates a composite etching solution combining phosphoric acid with an organic compound (alcohol or ether). This composite formulation leverages the strong etching capability of phosphoric acid for nitride while the organic component modulates the chemistry to suppress excessive oxide etching, achieving both high productivity and selectivity.
3Manufacturing precision
If trisilanol is used to lower oxide film etch rate, then selectivity is improved, but particles are generated and phosphoric acid cannot be recycled
Solution Approach 1:
The patent extracts the particle-generation problem by removing trisilanol from the etching composition and replacing it with an organic compound that achieves oxide film protection through a different mechanism. The organic solvent (alcohol or ether) provides selectivity control without causing the polymerization and particle formation that occurs with trisilanol.
Solution Approach 2:
The organic compound acts as an intermediary substance that mediates between the phosphoric acid etching action and the oxide film protection requirement. It modulates the etching chemistry to achieve selective nitride removal while preventing oxide attack, without generating particles that would contaminate the process or prevent acid recycling.
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 a high selectivity ratio of silicon nitride to oxide films, maintains stability at high temperatures, and significantly reduces particle size and generation, ensuring a stable and effective etching process for semiconductor devices.
Implementation Method 1
An etching composition comprising phosphoric acid and a compound having a specific chemical structure (Formula 1) that selectively removes a nitride film while minimizing an etch rate of an oxide film
Data Source
AI summary
The present invention relates to an etching composition, an etching method, and a method of preparing a semiconductor device using the same, and more particularly, to an etching composition comprising a compound capable of selectively removing a nitride film with a high selectivity while minimizing an etch rate of the oxide film, and a method of preparing a semiconductor device comprising an etching process using the etching composition.