Iodized Polymer Resist for EUV Lithography Defect Control

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Solution Overview

Problem

EUV lithography faces challenges with defects in mask blanks and low light transmittance pellicles, leading to increased defect occurrence and sensitivity issues due to low solubility of iodine atoms in alkaline developers, resulting in nano-bridging and pattern collapse in microelectronic device manufacturing.

Innovation Solution

A resist composition incorporating an iodized aromatic carboxylic acid type pendant-containing polymer is developed, which segregates on the resist film surface, enhancing light absorption and solubility in alkaline developers, thereby preventing nano-bridging and pattern collapse, and improving critical dimension uniformity and line width roughness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If iodine atoms are introduced into the base polymer to increase sensitivity through EUV absorption, then sensitivity is improved, but solubility in alkaline developer deteriorates leading to low dissolution rate and residue formation

Engineering Contradiction:

ImprovesensitivityVSAvoiddissolution rate

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent divides the polymer structure into two distinct components: a base polymer containing iodine atoms for EUV absorption and sensitivity enhancement, and a pendant polymer containing carboxylic acid groups for improved solubility in alkaline developer. This segmentation allows each component to fulfill its specific function independently, resolving the contradiction between sensitivity and dissolution rate.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention creates a composite polymer material by introducing pendant groups containing carboxylic acid moieties onto the iodine-containing base polymer backbone. This composite structure combines the high EUV absorption capability of iodine with the excellent alkaline solubility of carboxylic acid groups, achieving both high sensitivity and high dissolution rate simultaneously.

Inventive Principle:

Principle #40Composite materials

2Reliability

If fluorinated polymer additive is used to improve water repellency and reduce bridge defects, then surface solubility is improved, but outgassing from the resist film increases during EUV exposure

Engineering Contradiction:

Improvebridge defectsVSAvoidoutgassing

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical parameters of the polymer by introducing pendant groups with specific carboxylic acid structures that balance surface solubility improvement with reduced outgassing. The specific structural parameters of the pendant groups are optimized to achieve the right balance between preventing bridge defects and minimizing outgassing during EUV exposure.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If pattern rule is reduced to increase integration density and operating speed, then productivity is improved, but manufacturing precision deteriorates due to increased defect occurrence

Engineering Contradiction:

Improveintegration densityVSAvoiddefect control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent employs a specially designed resist polymer composition that is optimized for single-use in high-precision patterning. The pendant-containing polymer structure provides enhanced solubility and reduced outgassing that are critical for maintaining manufacturing precision at reduced pattern rules, enabling continued productivity improvement without sacrificing defect control.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 resist composition achieves high sensitivity, minimizes defects, and provides a wide process margin for forming precise line and hole patterns without residues, improving the overall performance in EUV lithography for advanced microelectronic devices.

Implementation Method 1

Iodine atoms have remarkably high absorption of EUV and thus achieve a sensitizing effect

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

a polymer having a specific iodized aromatic carboxylic acid as a pendant group... is added, there is obtained a resist composition which is effective for preventing nano-bridging and pattern collapse

Methodology Applied

Scientific EffectPhase separation:

Data Source

PatentUS11815814B2Iodized aromatic carboxylic acid type pendant-containing polymer, resist composition and patterning process

Publication Date: 2023.11.14 SHIN ETSU CHEMICAL CO LTD

AI summary

An iodized aromatic carboxylic acid type pendant-containing polymer is provided. A resist composition comprising the same offers a high sensitivity and is unsusceptible to nano-bridging, pattern collapse or residue formation, independent of whether it is of positive or negative tone.