Nitride Etching Composition for Oxide-Safe Semiconductor Processing
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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 decreased etch selectivity and particle generation, which can affect device characteristics.
Innovation Solution
A composition comprising a first inorganic acid, a specific additive represented by Chemical Formula 1, and a solvent, along with a second additive such as a silane inorganic acid salt, is used to selectively etch nitride films with respect to oxide films, controlling the etching process temperature between 50° C to 300° C to enhance selectivity and prevent particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
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 parameters of the etching composition by replacing phosphoric acid with a specific organic acid (having 1-10 carbon atoms and specific functional groups) to achieve higher etch selectivity between nitride film and oxide film, thereby preventing oxide film damage while maintaining nitride film removal capability
Solution Approach 2:
The patent uses a readily available organic acid with specific structural characteristics instead of phosphoric acid, creating a cost-effective etching solution that provides superior selectivity without requiring complex or expensive materials
2Productivity
If phosphoric acid concentration is increased to improve etching speed, then nitride film removal efficiency increases, but handling difficulty and corrosion increase
Solution Approach 1:
The patent replaces phosphoric acid with a common organic acid that is easier to handle and less corrosive, maintaining etching effectiveness while significantly improving safety and ease of operation in semiconductor manufacturing environments
3Manufacturing precision
If deionized water is added to phosphoric acid to prevent etch rate decrease, then oxide film protection improves, but nitride film etching defects increase
Solution Approach 1:
The patent changes the fundamental chemical composition from phosphoric acid-based to organic acid-based etching solution, which inherently provides better etch rate control and prevents both oxide film damage and nitride film etching defects simultaneously
4Productivity
If silicic acid or silicic acid salt is used in etching composition, then nitride film etching is enhanced, but particle generation occurs affecting substrate
Solution Approach 1:
The patent uses a simple organic acid compound instead of silicic acid or silicic acid salts, achieving effective nitride film removal without the particle generation problem that plagues silicic acid-based etching compositions
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, allowing for precise control of effective field oxide height and preventing damage to oxide films, thereby improving device characteristics and process stability.
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
The deionized water is added in order to prevent a decrease in the etch rate and a variation in the etch selectivity for oxide films
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.