Chemically Amplified Resist Patterning for High Aspect Ratio Verticality

Solution Overview

Problem

Conventional double patterning methods often result in pattern collapse and poor verticality issues, particularly when forming very fine patterns with high aspect ratios on substrates.

Innovation Solution

A method involving the use of a chemically amplified resist composition, where an underlayer film and hard mask are formed, followed by multiple resist film applications and selective exposure and development steps to create a pattern, allowing for the formation of a high aspect ratio pattern through etching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If conventional double patterning methods are used to form fine patterns, then pattern miniaturization is achieved, but pattern collapse and poor verticality occur in high aspect ratio structures

Engineering Contradiction:

Improvepattern dimensionVSAvoidpattern verticality

Core Design Contradiction:

Length of moving objectVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by dividing the patterning process into multiple discrete steps (first resist pattern formation, mandrel removal, second resist pattern formation) rather than attempting to form the final pattern in a single step. This multi-stage approach allows each step to be optimized independently, preventing pattern collapse while achieving the desired fine dimensions and verticality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs preliminary action by forming a first resist pattern and using it as a mandrel before forming the final pattern. This preliminary structure provides mechanical support during the patterning process, enabling the formation of high aspect ratio patterns with good verticality that would otherwise collapse.

Inventive Principle:

Principle #10Preliminary action

2Length of moving object

If conventional double patterning methods are used to form fine patterns, then pattern miniaturization is achieved, but pattern collapse occurs in high aspect ratio structures

Engineering Contradiction:

Improvepattern dimensionVSAvoidpattern stability

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The patent employs preliminary action by forming a first resist pattern and using it as a mandrel before forming the final pattern. This preliminary structure provides mechanical support during the patterning process, enabling the formation of high aspect ratio patterns with good verticality that would otherwise collapse.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediary mandrel structure (the first resist pattern) that mediates between the substrate and the final pattern formation. This intermediary provides the necessary mechanical support and structural integrity during the patterning process, preventing pattern collapse while allowing the final fine pattern to be formed with high reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If multiple resist film applications and development steps are conducted, then very fine patterns with high aspect ratio are formed, but process complexity increases

Engineering Contradiction:

Improvepattern aspect ratioVSAvoidpatterning process steps

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the patterning process into multiple discrete steps (first resist pattern formation, mandrel removal, second resist pattern formation) rather than attempting to form the final pattern in a single step. This multi-stage approach allows each step to be optimized independently, preventing pattern collapse while achieving the desired fine dimensions and verticality.

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 method enables the formation of very fine patterns with improved verticality and aspect ratio on substrates, addressing the limitations of conventional double patterning techniques.

Implementation Method 1

a chemically amplified resist composition, which includes a base component that exhibits changed alkali solubility under the action of acid and an acid generator that generates acid upon exposure

Methodology Applied

Scientific EffectPhotochemical reaction: Photopolymerisation

Implementation Method 2

an acid generator that generates acid upon exposure (for example, see Patent Document 1)

Methodology Applied

Scientific EffectPhotolysis: Photodissociation

Data Source

PatentUS8178284B2Method of forming pattern

Publication Date: 2012.05.15 TOKYO OHKA KOGYO CO LTD

AI summary

A method of forming a pattern including: forming an underlayer film on a support using an underlayer film-forming material, forming a hard mask on the underlayer film using a silicon-based hard mask-forming material, forming a first resist film by applying a chemically amplified positive resist composition to the hard mask, forming a first resist pattern by selectively exposing the first resist film through a first mask pattern and then performing developing, forming a first pattern by etching the hard mask using the first resist pattern as a mask, forming a second resist film by applying a chemically amplified positive silicon-based resist composition to the first pattern and the underlayer film, forming a second resist pattern by selectively exposing the second resist film through a second mask pattern and then performing developing, and forming a second pattern by etching the underlayer film using the first pattern and the second resist pattern as a mask.