Silicon Nitride Etching Selectivity via Silane Mediator

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Solution Overview

Problem

Existing etching compositions for silicon nitride layers often lack selectivity over silicon oxide layers, leading to unintended etching of both materials, particularly when using phosphoric acid-based solutions.

Innovation Solution

An etching composition comprising a phosphoric acid compound, water, and a silane compound represented by Formula 1, which includes specific functional groups that enhance etching selectivity by selectively targeting silicon nitride layers while minimizing etching of silicon oxide layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a mixture of phosphoric acid and water is used as an etching solution for silicon nitride layer, then etching capability is achieved, but both silicon nitride layer and silicon oxide layer are etched simultaneously

Engineering Contradiction:

Improveetching selectivityVSAvoidunintended etching of silicon oxide layer

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

A silane-based compound is introduced as an intermediary substance that selectively reacts with silicon oxide to form a protective layer, mediating between the phosphoric acid etching solution and the silicon oxide layer to prevent unwanted etching while allowing silicon nitride etching to proceed

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The etching solution composition is modified by adding silane-based compounds to change the chemical parameters of the solution, creating a multi-component system that exhibits selective etching behavior through differential reaction rates with different silicon-based materials

Inventive Principle:

Principle #35Parameter changes

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 etching selectivity for silicon nitride layers over silicon oxide layers, preventing abnormal growth and precipitate formation, and maintaining effective etching performance.

Implementation Method 1

an etching composition for silicon nitride, which includes: a phosphoric acid compound; water; and at least one of a silane compound represented by Formula 1 and a reaction product thereof

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

a phosphoric acid compound; water; and at least one of a silane compound

Methodology Applied

Scientific EffectAcid etching: Chemical Bonding

Data Source

PatentUS11608471B2Composition for etching silicon nitride film and etching method using same

Publication Date: 2023.03.21 SAMSUNG SDI CO LTD

AI summary

An etching composition for silicon nitride comprising: a phosphoric acid compound; water; and at least one of a silane compound represented by Formula 1, below, and a reaction product thereof, and an etching method using the same are disclosed,