Semiconductor Etching Composition for Selective Nitride Removal
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Solution Overview
Problem
Current etching processes for semiconductor manufacturing face challenges in achieving high selectivity for nitride films over oxide films, often resulting in defects and particle generation, which affect device characteristics and require additional processing steps.
Innovation Solution
A composition comprising a first inorganic acid, a specific additive represented by Chemical Formula 1, and a solvent, along with a silane inorganic acid salt, is used to selectively etch nitride films while minimizing oxide film etching, with the etching process conducted at temperatures between 50°C to 300°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phosphoric acid is used to etch nitride films, then the nitride film can be removed, but the etch selectivity between nitride film and oxide film decreases causing oxide film damage
Solution Approach 1:
The patent changes the chemical composition parameters of the etching solution by replacing phosphoric acid with a mixture of hydrofluoric acid (0.1-5 wt%) and nitric acid (65-99.9 wt%), which fundamentally alters the etching mechanism to achieve high selectivity for nitride films while protecting oxide films from damage
Solution Approach 2:
The patent uses a composite etching solution combining hydrofluoric acid and nitric acid in specific proportions, where hydrofluoric acid provides nitride film etching capability and nitric acid offers oxidation protection to oxide films, achieving synergistic effect that resolves the selectivity contradiction
2Manufacturing precision
If deionized water is added to phosphoric acid to prevent etch rate decrease, then oxide film protection is improved, but process stability deteriorates due to sensitivity to water amount variations
Solution Approach 1:
The patent changes the fundamental chemical composition from phosphoric acid-based to hydrofluoric acid-nitric acid-based etching solution, eliminating the need for deionized water addition and achieving process stability that is not sensitive to water amount variations while maintaining oxide film protection
Solution Approach 2:
The patent replaces the unstable phosphoric acid system with a stable hydrofluoric acid-nitric acid system that does not require continuous adjustment or addition of components, providing reliable and consistent etching performance
3Manufacturing precision
If phosphoric acid is used for wet etching, then additional processing time is required to achieve sufficient nitride film removal, but this increases overall manufacturing time
Solution Approach 1:
The patent changes the etching chemistry from phosphoric acid to hydrofluoric acid-nitric acid mixture, which provides significantly higher etching efficiency for nitride films, reducing the required etching time while ensuring complete nitride film removal
Solution Approach 2:
The patent uses the highly effective hydrofluoric acid-nitric acid etching solution to rapidly remove nitride films in a short time, skipping the lengthy etching process required by phosphoric acid while maintaining complete removal quality
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 provides high selectivity for nitride films over oxide films, preventing particle generation and maintaining device characteristics, allowing for precise control of effective field oxide height and improving semiconductor device manufacturing efficiency.
Implementation Method 1
a composition for etching, comprising a first inorganic acid, a first additive represented by Chemical Formula 1, and a solvent
Implementation Method 2
the etching process conducted at temperatures between 50°C to 300°C
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.