Silane-Modified Etching Composition for Selective Nitride Removal
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Solution Overview
Problem
Current etching compositions for semiconductor manufacturing struggle to selectively remove nitride films while minimizing oxide film etching rates, often resulting in defects, particle generation, and reduced etching selectivity, which affects device characteristics and requires additional processing steps.
Innovation Solution
An etching composition comprising phosphoric acid, a silane compound, and an organic phosphate, represented by specific formulas, is developed to enhance the selectivity and stability of nitride film removal, minimizing oxide film etching and preventing particle generation, with optimal concentrations of each component ensuring effective etching performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phosphoric acid and deionized water are used for wet etching of nitride film, then etching rate is maintained, but etching selection ratio to oxide film decreases and defects occur
Solution Approach 1:
The patent changes the chemical composition parameters of the etching solution by introducing silane compounds and organic phosphates to phosphoric acid-based solutions. This modification enables the solution to selectively etch nitride films while maintaining high etching rates and preventing oxide film damage, thereby resolving the contradiction between productivity and manufacturing precision.
Solution Approach 2:
The patent creates a composite etching solution by combining phosphoric acid with silane compounds and organic phosphates. This composite formulation achieves both high etching rate for nitride films and high selectivity by preventing oxide film etching, thus resolving the technical contradiction between productivity and manufacturing precision.
2Productivity
If silicic acid or silicate is added to phosphoric acid for etching, then etching performance is improved, but particles are generated that affect the substrate
Solution Approach 1:
The patent uses silane compounds that decompose during the etching process to form protective layers, rather than using silicic acid or silicate that persist as particles. The silane compounds are consumed during etching, providing protective functionality without leaving harmful residues on the substrate.
Solution Approach 2:
The patent changes the chemical form from silicic acid/silicate to silane compounds, which have different decomposition characteristics. The silane compounds decompose to form protective silicon oxide layers during etching, preventing particle generation while maintaining etching performance.
3Manufacturing precision
If conventional silane-based additives are added to etching composition, then etching selectivity is improved, but solubility is too low causing precipitation of particles
Solution Approach 1:
The patent creates a composite system combining silane compounds with organic phosphates in phosphoric acid. The organic phosphates act as solubility enhancers and stabilizers, preventing precipitation of particles while maintaining the high etching selectivity provided by the silane compounds.
Solution Approach 2:
The organic phosphates serve as intermediaries that improve the solubility and stability of silane compounds in the phosphoric acid-based etching solution. This mediation prevents precipitation and maintains composition stability while preserving the beneficial etching selectivity of silane compounds.
4Productivity
If phosphoric acid is used for removing nitride film, then etching rate is sufficient, but oxide film is also etched due to reduced selection ratio
Solution Approach 1:
The patent modifies the chemical parameters of phosphoric acid by adding silane compounds and organic phosphates. This composition change enables the solution to differentiate between nitride and oxide films, etching nitride at high rates while protecting oxide films from etching.
Solution Approach 2:
The silane compounds and organic phosphates act as intermediaries that selectively interact with nitride films to enhance etching rates while forming protective layers on oxide films, thereby preventing harmful oxide film etching while maintaining high productivity.
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 etching selection ratio for nitride films over oxide films, maintains stability over time, and prevents particle formation, thereby improving semiconductor device characteristics and manufacturing efficiency.
Implementation Method 1
In a wet etching process for removing the nitride film, a mixture of phosphoric acid and deionized water is generally used
Implementation Method 2
An etching composition comprising phosphoric acid, a silane compound containing at least one silicon (Si) atom
Implementation Method 3
a silane-based additive, which is an additive added to a conventional etching composition, has solubility too low to secure optimal solubility, thereby causing precipitation of particles
Data Source
AI summary
An etching composition includes phosphoric acid, a silane compound comprising at least one silicon (Si) atom, and an organic phosphate represented by Formula 1 below:wherein R1 to R3 are independently hydrogen, or a substituted or unsubstituted hydrocarbyl group, and at least one of R1 to R3 is a substituted or unsubstituted hydrocarbyl group.