Silicon Nitride Etching Composition for High-Selectivity Wet Processing
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Solution Overview
Problem
Current silicon nitride film etching compositions have low etch selection ratios relative to silicon oxide films, often produce precipitates, and exhibit etch rate drifts during repeated use, making them unsuitable for high-temperature semiconductor manufacturing processes.
Innovation Solution
A silicon nitride film etching composition comprising phosphoric acid, silsesquioxane, and water, with specific chemical formulations that inhibit precipitate formation and maintain high etch selection ratios and stability over extended processing times, including the use of an alcoholic solvent and inorganic acids to enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional silicon nitride film etching compositions are used, then etching can be performed, but the etch selection ratio relative to silicon oxide films is low
Solution Approach 1:
The patent changes the chemical composition parameters of the etching solution by incorporating phosphoric acid as the primary etchant and adding silsesquoxane as a modifier. This parameter change achieves a high etch selection ratio for silicon nitride films while maintaining compatibility with silicon oxide films, resolving the contradiction between selective etching capability and process feasibility
Solution Approach 2:
The patent creates a composite etching solution by combining phosphoric acid with silsesquoxane compounds. This composite formulation synergistically enhances the etch selection ratio for silicon nitride while suppressing etching of silicon oxide, thereby achieving high manufacturing precision without sacrificing ease of manufacture
2Productivity
If conventional etching compositions are used, then etching process can proceed, but precipitates are produced during etching
Solution Approach 1:
The silsesquoxane compound acts as an intermediary substance in the etching solution that prevents direct harmful interactions between phosphoric acid and the silicon nitride film surface. This intermediary mechanism suppresses precipitate formation while maintaining continuous etching productivity
Solution Approach 2:
By modifying the chemical parameters of the etching solution through phosphoric acid and silsesquoxane combination, the patent changes the reaction dynamics to prevent precipitate formation, thereby ensuring continuous productive etching without harmful byproducts
3Duration of action of moving object
If conventional etching compositions are used, then initial etching can be performed, but etch rate drift occurs during repeated use
Solution Approach 1:
The phosphoric acid-based etching solution with silsesquoxane maintains continuous and stable etching action over repeated uses. The composition resists degradation and maintains consistent etch rates, ensuring productivity without drift even during prolonged and repeated etching operations
Solution Approach 2:
The patent employs a disposable etching solution formulation that, while simple in composition (phosphoric acid and silsesquoxane), maintains stable performance throughout its service life. The solution can be used repeatedly without significant etch rate drift, eliminating the need for frequent replacement while maintaining productivity
4Temperature
If conventional etching compositions are used, then etching can be performed, but performance degrades at elevated temperatures
Solution Approach 1:
The patent optimizes the chemical parameters of the etching solution by using phosphoric acid and silsesquoxane, which together maintain stable etch selection ratio performance across a wide temperature range. This parameter optimization ensures high manufacturing precision even at elevated temperatures during semiconductor manufacturing processes
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 etch selection ratio for silicon nitride films relative to silicon oxide films, prevents precipitate formation, and maintains etch rate stability even at elevated temperatures and during repeated use, thereby improving semiconductor device manufacturing efficiency and reducing defects.
Implementation Method 1
a phosphoric acid, silsesquoxane, and a residual amount of water
Implementation Method 2
a phosphoric acid, silsesquoxane, and a residual amount of water
Data Source
AI summary
Provided are a silicon nitride film etching composition, a method of etching a silicon nitride film using the same, and a manufacturing method of a semiconductor device. Specifically, a silicon nitride film may be highly selectively etched as compared with a silicon oxide film, and when the composition is applied to an etching process at a high temperature and a semiconductor manufacturing process, not only no precipitate occurs but also anomalous growth in which the thickness of the silicon oxide film is rather increased does not occur, thereby minimizing defects and reliability reduction.