SiCN Seed Layer Plasma Damage Mitigation in ALD Film Formation

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Solution Overview

Problem

Existing methods for forming silicon nitride films using ammonia, silane, and carbon hydride gases face challenges in maintaining film quality and reducing damage to the seed layer during plasma-enhanced ALD processes, particularly due to plasma exposure.

Innovation Solution

A method involving the formation of a SiCN seed layer by thermal ALD, followed by a SiN protective layer also by thermal ALD, and then a SiN bulk layer by plasma-enhanced ALD, with specific gas supply and purge steps to minimize plasma exposure and enhance film quality, using a processing apparatus with controlled gas supply and plasma generation mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If plasma enhanced ALD is used to form SiN bulk layer directly on SiCN seed layer, then deposition efficiency is improved, but damage to the SiCN seed layer increases due to plasma exposure

Engineering Contradiction:

Improvedeposition efficiencyVSAvoidplasma damage to seed layer

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

A SiN protective layer is introduced as an intermediary between the SiCN seed layer and the plasma environment. This protective layer blocks plasma exposure to the SiCN seed layer during subsequent plasma enhanced ALD processing, preventing carbon loss and film quality degradation while still allowing the plasma process to proceed efficiently for bulk layer deposition

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If silane family gas is intermittently supplied to form silicon nitride film, then film composition control is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvefilm composition controlVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The film formation process is segmented into distinct stages: thermal ALD for seed layer formation with intermittent silane supply for precise composition control, followed by plasma enhanced ALD for efficient bulk layer deposition. This segmentation allows optimization of each stage independently, maintaining composition precision while managing overall process complexity

Inventive Principle:

Principle #1Segmentation

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

This approach reduces damage to the SiCN seed layer and maintains film quality by using a SiN protective layer to block plasma, resulting in improved plasma resistance and composition of the SiCN seed layer.

Implementation Method 1

forming a SiCN seed layer on a substrate by a thermal ALD (atomic layer deposition), forming a SiN protective layer on the SiCN seed layer by a thermal ALD

Methodology Applied

Scientific EffectAtomic Layer Deposition: Chemical Vapour Deposition

Implementation Method 2

forming a SiN bulk layer on the SiN protective layer by a plasma enhanced ALD

Methodology Applied

Scientific EffectPlasma Enhanced Chemical Vapour Deposition: Plasma Enhanced Chemical Vapour Deposition

Implementation Method 3

a plasma enhanced ALD in which a silicon-containing gas and ammonia gas are used as process gases, and ammonia gas is formed into plasma

Methodology Applied

Scientific EffectPlasma: Plasma

Data Source

PatentUS20220238335A1Method for forming film and processing apparatus

Publication Date: 2022.07.28 TOKYO ELECTRON LTD

AI summary

A method for forming a film, the method including: forming a SiCN seed layer on a substrate by a thermal ALD, forming a SiN protective layer on the SiCN seed layer by a thermal ALD, and forming a SiN bulk layer on the SiN protective layer by a plasma enhanced ALD.