Selective Resist Deposition for EUV Pattern Transfer Selectivity

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Solution Overview

Problem

The challenge in semiconductor manufacturing is the poor etch selectivity between EUV photoresists and underlayers, leading to incomplete pattern transfer and depletion of the EUV photoresist during the etching process, which affects downstream pattern transfer into remaining layers.

Innovation Solution

A method involving a resist layer with carbon and fluorine, selectively depositing a protective layer over the resist layer using chemical differences, and transferring the pattern into the underlayer with enhanced etch selectivity, thereby preserving the resist layer's structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If an etching process is used to transfer the pattern into the underlayer, then the pattern transfer efficiency is improved, but the EUV photoresist is significantly etched or completely removed

Engineering Contradiction:

Improvepattern transfer efficiencyVSAvoidresist layer integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A protective layer is deposited selectively over the EUV photoresist to act as an intermediary barrier during the etching process. This protective layer prevents the etching chemistry from attacking the photoresist while allowing efficient pattern transfer into the underlayer, thus resolving the contradiction between etching efficiency and resist integrity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective layer is applied selectively only where needed (over the photoresist regions requiring protection) rather than uniformly across all surfaces. This localized application maintains resist integrity in critical areas while allowing the etching process to proceed efficiently into the underlayer

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If a high dose of EUV radiation is used to ensure complete pattern development in the photoresist, then the patterning quality is improved, but the throughput of the exposure process decreases

Engineering Contradiction:

Improvepatterning qualityVSAvoidexposure process throughput

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The underlayer acts as a mediator that enhances the chemical reaction rate within the EUV photoresist by introducing additional reactive species. This allows achieving complete pattern development at lower EUV radiation doses, thereby improving throughput while maintaining patterning quality

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The introduction of the underlayer changes the chemical environment parameters within the photoresist, increasing the concentration of reactive species and accelerating the chemical reactions. This parameter change enables reduced exposure doses while maintaining pattern development quality

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the underlayer contains carbon and fluorine to enhance chemical reaction rate, then the EUV patterning efficiency is improved, but the etch selectivity between photoresist and underlayer deteriorates

Engineering Contradiction:

ImproveEUV patterning efficiencyVSAvoidetch selectivity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The protective layer serves as an intermediary that decouples the relationship between the etching process and the photoresist-underlayer interface. It allows the use of carbon and fluorine in the underlayer for enhanced patterning efficiency while preventing these materials from causing poor etch selectivity issues

Inventive Principle:

Principle #24Intermediary (Mediator)

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 maintains the resist layer's integrity during pattern transfer, allowing for reduced EUV lithography doses and improved throughput by preventing significant etching of the resist layer.

Implementation Method 1

The underlayer is designed to add species into the overlying EUV photoresist when exposed to the EUV radiation. These additional species can be used by the EUV photoresist to increase the chemical reaction rate within the EUV photoresist

Methodology Applied

Scientific EffectChemical amplification:

Implementation Method 2

applying a protective layer over surfaces of the CAR with a dry deposition process that includes an organic precursor and/or an organometallic precursor

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Implementation Method 3

carbon-fluorine bonds at a surface of the underlayer reduce deposition of the protective layer on the underlayer

Methodology Applied

Scientific EffectSelective deposition:

Implementation Method 4

transferring the pattern into the underlayer with an etching process

Methodology Applied

Scientific EffectPlasma etching:

Data Source

PatentUS20260072356A1Selective deposition and pattern transfer for chemically amplified resists

Publication Date: 2026.03.12 APPLIED MATERIALS INC

AI summary

Embodiments described herein relate to a method that includes forming a resist layer over an underlayer that includes carbon and fluorine, and forming a pattern in the resist layer with a lithography process. In an embodiment, the method further includes selectively depositing a layer over surfaces of the resist layer. In an embodiment, the method further includes transferring the pattern into the underlayer with an etching process.