EUV Resist Patterning With Electric Field for Lower Edge Roughness

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Solution Overview

Problem

Lithography techniques using extreme ultraviolet light (EUV) face challenges in reducing line width roughness (LWR) and line edge roughness (LER) of resist patterns, which are critical for forming fine patterns in semiconductor devices as integration density increases.

Innovation Solution

A method and apparatus that involve forming a resist pattern by applying an electric field in the thickness direction of a resist layer while exposing it to EUV light, which enhances the transfer of the pattern image and reduces unwanted exposure, thereby improving the resolution and accuracy of the resist pattern.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If EUV light is used for lithography, then fine patterns can be formed, but line width roughness and line edge roughness increase

Engineering Contradiction:

Improvepattern finenessVSAvoidline width roughness and line edge roughness

Core Design Contradiction:

Manufacturing precisionVSManufacturing precision

Solution Approach 1:

The patent applies an electric field during EUV exposure to modify the physical state and behavior of electrons in the resist layer. By changing the electrical parameter (applying an electric field), the diffusion of photo-generated electrons is controlled, reducing electron blur and improving line edge roughness and line width roughness while maintaining the ability to form fine patterns with EUV light

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The electric field is applied before and during the EUV exposure process to pre-position and control electron movement. This preliminary application of the electric field prevents excessive electron diffusion before the exposure is complete, thereby reducing line edge roughness and improving overall pattern quality

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 application of an electric field during EUV exposure increases the number and energy of electrons generated, limiting their diffusion and reducing electron blur, resulting in improved line width roughness, line edge roughness, and critical dimension (CD) of the resist pattern, thus enhancing the lithography process.

Implementation Method 1

applying an electric field to the resist layer in a thickness direction of the resist layer

Methodology Applied

Scientific EffectElectric field: Electric Field

Implementation Method 2

exposing a portion of the resist layer to extreme ultraviolet (EUV) light

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS11754925B2Methods and apparatus for forming resist pattern using EUV light with electric field

Publication Date: 2023.09.12 SK HYNIX INC

AI summary

A method and apparatus for forming a resist pattern may be provided. In the method for forming a resist pattern, a resist layer may be formed on a base layer, an electric field may be applied to the resist layer in a thickness direction of the resist layer, and a portion of the resist layer may be exposed with extreme ultraviolet (EUV) light while applying the electric field. A lithography apparatus for performing the method of forming a resist pattern may include at least an exposure part and an electric field forming part. The exposure part may be configured to expose a portion of the resist layer with extreme ultraviolet (EUV) light. The electric field forming part may be configured to apply an electric field to the resist layer.