Silyl Phosphate Etching Composition for Nitride Film Selectivity
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Solution Overview
Problem
Current etching compositions for semiconductor fabrication fail to selectively remove nitride films while minimizing the etch rate of oxide films, leading to decreased etching selectivity and potential particle generation, which affects device characteristics.
Innovation Solution
An etching composition comprising a silyl phosphate compound, phosphoric acid, and deionized water, which provides high selectivity for nitride film removal over oxide films, minimizing oxide film etch rate and preventing particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phosphoric acid is used to remove nitride film, then nitride film removal is achieved, but oxide film etch rate increases and etching selectivity decreases
Solution Approach 1:
The patent modifies the chemical composition parameters of the etching solution by adding silyl phosphate compound to phosphoric acid, changing the chemical environment to achieve differential etching rates. This parameter change enables selective removal of nitride film while suppressing oxide film etching, resolving the selectivity problem.
Solution Approach 2:
The patent creates a composite etching solution combining phosphoric acid and silyl phosphate compound. This composite formulation synergistically achieves high nitride film etch rate while maintaining low oxide film etch rate, thereby improving etching selectivity without sacrificing productivity.
2Productivity
If hydrofluoric acid and phosphoric acid are used together, then nitride film etching is enhanced, but etching selectivity for nitride film with respect to oxide film decreases
Solution Approach 1:
The patent replaces the HF-H3PO4 composition with a H3PO4-silyl phosphate compound composition, changing the chemical parameters to achieve the desired selectivity. The silyl phosphate compound specifically enhances nitride film etching without the harmful side effect of increased oxide film etching that occurs with HF.
3Productivity
If silicate or silicic acid is added to phosphoric acid, then nitride film etching is improved, but particle generation occurs that affects substrate
Solution Approach 1:
The patent uses silyl phosphate compound as a temporary etching agent that performs its function and decomposes without generating harmful particles. Unlike silicate or silicic acid that persist and cause particle contamination, the silyl phosphate compound is consumed in the etching process without leaving harmful residues on the substrate.
4Ease of manufacture
If phosphoric acid is used for nitride film removal, then wet-etching process is simple, but additional processes are required due to decreased selectivity
Solution Approach 1:
The patent enhances the functionality of phosphoric acid by adding silyl phosphate compound, creating a multi-functional etching solution that both removes nitride film efficiently and maintains high selectivity against oxide films. This single solution performs multiple functions that previously required separate processes, improving overall process efficiency without complicating the manufacturing flow.
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 etching composition achieves high selectivity for nitride films, allowing controlled effective field oxide height and preventing damage to oxide films, thereby improving semiconductor device characteristics and process stability.
Implementation Method 1
an etching composition including a silyl phosphate compound, phosphoric acid and deionized water
Data Source
AI summary
The present invention provides an etching composition, comprising a silyl phosphate compound, phosphoric acid and deionized water, and a method for fabricating a semiconductor, which includes an etching process employing the etching composition. The etching composition of the invention shows a high etching selectivity for a nitride film with respect to an oxide film. Thus, when the etching composition of the present invention is used to remove a nitride film, the effective field oxide height (EEH) may be easily controlled by controlling the etch rate of the oxide film. In addition, the deterioration in electrical characteristics caused by damage to an oxide film or etching of the oxide film may be prevented, and particle generation may be prevented, thereby ensuring the stability and reliability of the etching process.