Silane Compound Etchant for Nitride Film Selectivity
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Solution Overview
Problem
Current etchant compositions for removing nitride films in semiconductor manufacturing suffer from low selectivity towards oxide films, leading to defects and particle formation, which affect device characteristics and require additional processing steps.
Innovation Solution
An etchant composition comprising phosphoric acid and a silane compound, specifically designed to enhance the selectivity of nitride film etching over oxide films, minimizing oxide film etching and preventing particle occurrence, with the silane compound protecting the oxide film and maintaining etching speed consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phosphoric acid and deionized water mixture is used for removing nitride film, then etching rate of nitride film is maintained, but etching selectivity to oxide film deteriorates and defects arise
Solution Approach 1:
The patent changes the chemical composition parameters of the etchant by replacing deionized water with a specific organic compound (carboxylic acid or sulfonic acid) having controlled molecular weight and functional groups. This parameter change achieves both high nitride film etching rate and improved selectivity against oxide film, resolving the contradiction between productivity and manufacturing precision
Solution Approach 2:
The patent creates a composite etchant system combining phosphoric acid with specific organic compounds (carboxylic acid or sulfonic acid). This composite formulation synergistically enhances nitride film removal while providing protective action on oxide films, simultaneously achieving high etching rate and high selectivity
2Manufacturing precision
If phosphoric acid with silicate or silicic acid is used, then etching selectivity is improved, but particle formation occurs affecting substrate
Solution Approach 1:
The patent replaces silicate/silicic acid additives with short-lived organic compounds (carboxylic acid or sulfonic acid) that perform their protective function during etching and then decompose or are easily removed, preventing persistent particle formation on substrates while maintaining high etching selectivity
Solution Approach 2:
The patent changes the additive type from inorganic silicates to organic carboxylic acids or sulfonic acids with specific molecular weight ranges. This parameter change eliminates particle formation issues associated with silicates while preserving and enhancing etching selectivity
3Productivity
If phosphoric acid is used for nitride film removal, then nitride film etching is achieved, but oxide film is also etched reducing effective field oxide height
Solution Approach 1:
The patent modifies the etchant composition by adding specific organic compounds (carboxylic acid or sulfonic acid) that selectively enhance nitride film reactivity while forming protective complexes with oxide surfaces. This parameter change enables complete nitride removal while preserving oxide film integrity and effective field oxide height
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 etchant composition achieves a high selectivity ratio for nitride film etching while minimizing oxide film etching, preventing particle formation and ensuring stable device characteristics by using a silane compound that protects the oxide film and maintains consistent etching speed.
Implementation Method 1
the silane compound protecting the oxide film
Implementation Method 2
An etchant composition comprising phosphoric acid and a silane compound... selectively remove a nitride film while minimizing an etching rate of an oxide film
Data Source
AI summary
An etchant composition includes a silane compound represented by the following Chemical Formula 1:wherein R1 to R6 are independently hydrogen, halogen, a substituted or unsubstituted C1-C20 hydrocarbyl group, a phenyl group, a C1-C20 alkoxy group, a carboxy group, a carbonyl group, a nitro group, a tri (C1-C20)alkylsilyl group, a phosphoryl group, or a cyano group, L is a direct bond or C1-C3 hydrocarbylene, A is an n-valent radical, and n is an integer of 1 to 4.