Etch-Resistant TiO2 Spacer for Sidewall Image Transfer

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Solution Overview

Problem

Titanium Oxide spacer films used in sidewall image transfer applications are prone to modification and increased spacer loss during etch back processes, leading to critical dimension blowout and thickness loss in wet clean solutions.

Innovation Solution

Creating an etch-resistant Titanium Oxide film by exposing the spacer to high RF plasma conditions of at least 500 W and temperatures of at least 100 C, followed by post-anneal processing under low RF conditions, to enhance film density and hardness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Titanium Oxide spacer is deposited using conventional ALD or PEALD, then the spacer material provides less erosion and high selectivity during etch, but the spacer gets modified during etch back/mandrel removal and exhibits high wet etch rate in common wet clean solutions leading to increased spacer loss and critical dimension blow out

Engineering Contradiction:

Improveetch selectivityVSAvoidspacer loss

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies parameter changes by modifying the deposition temperature (at least 100°C) and plasma conditions (RF power at least 500 W for at least 1 second) during ALD/PEALD processing. These parameter changes transform the TiO2 film properties to achieve etch resistance while maintaining the desired selectivity and reducing spacer loss during wet clean processing

Inventive Principle:

Principle #35Parameter changes

2Strength

If Titanium Oxide spacer is exposed to high RF plasma conditions and elevated temperatures, then the film density and hardness are enhanced providing etch resistance, but the processing complexity increases

Engineering Contradiction:

Improvefilm densityVSAvoidprocessing complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by performing the high RF plasma exposure and elevated temperature treatment during the deposition process itself, rather than as a separate post-processing step. This integrates the film modification into the existing ALD/PEALD workflow, enhancing film density without significantly increasing overall process complexity

Inventive Principle:

Principle #10Preliminary action

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 resulting film exhibits reduced wet etch rates and spacer loss, maintaining film integrity and preventing critical dimension blowout during wet clean processing.

Implementation Method 1

depositing the Titanium Oxide spacer further comprises at least one of exposing the Titanium Oxide spacer to at least 100 C or plasma conditions of RF power are at least 500 W for at least 1 second

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 2

Annealing the Titanium Oxide spacer, and applying post anneal processing comprising low RF conditions ranging from 0.5 to 500 W

Methodology Applied

Scientific EffectAnnealing: Annealing

Data Source

PatentUS10366879B2Dry and wet etch resistance for atomic layer deposited TiO2 for SIT spacer application

Publication Date: 2019.07.30 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

Embodiments describing an approach for creating an etch resistant Titanium Oxide film for sidewall image transfer (SIT) spacer application. Generating a mandrel formation, and depositing a Titanium Oxide spacer on the mandrel formation, wherein depositing the Titanium Oxide spacer further comprises at least one of exposing the Titanium Oxide spacer to at least 100 C or plasma conditions of RF power are at least 500 W for at least 1 second.