Resist Topcoat Composition for EUV Lithography Pattern Uniformity
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Solution Overview
Problem
Existing photolithographic processes face challenges with pattern dispersion deterioration, such as roughness and in-point uniformity, due to extreme ultraviolet (EUV) light exposure, which affects the formation of fine patterns in semiconductor manufacturing.
Innovation Solution
A resist topcoat composition is developed, comprising a copolymer with specific structural units, an acidic compound containing fluorine, and a solvent. This composition is applied to the photoresist layer to reduce pattern deterioration and improve sensitivity during EUV exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If EUV light is irradiated to the photoresist, then the photoresist pattern can be formed, but pattern dispersion deterioration occurs due to photo shot noise and EUV absorption differences
Solution Approach 1:
A topcoat layer is introduced as an intermediary between the EUV light source and the photoresist. This topcoat absorbs the EUV light before it reaches the photoresist, creating a more uniform energy distribution and reducing the harmful effects of photo shot noise and EUV absorption differences that cause pattern dispersion deterioration.
Solution Approach 2:
The topcoat is composed of specific materials with controlled optical properties that change the energy distribution parameters of the EUV light. By selecting appropriate materials and thicknesses, the topcoat modifies the photon energy distribution to reduce random variations and absorption differences, thereby improving pattern uniformity.
2Manufacturing precision
If a topcoat is added to reduce pattern dispersion, then pattern uniformity improves, but the process complexity increases
Solution Approach 1:
The photolithography process is segmented into additional steps: applying the topcoat, exposing through the topcoat, and developing. This segmentation allows the topcoat to perform its function of uniforming EUV light distribution while the subsequent development step removes the topcoat, isolating the complexity to a manageable set of additional process steps.
Solution Approach 2:
The topcoat is designed as a temporary, disposable layer that is applied only during the critical exposure step and then completely removed in the development process. This disposable approach allows the use of specialized materials optimized for EUV light uniformity without leaving permanent structural changes in the final pattern.
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 topcoat composition effectively reduces pattern dispersion issues like line edge roughness, line width roughness, and in-point uniformity, significantly improving the in-point uniformity of pillar patterns and enabling the formation of finer photoresist patterns.
Implementation Method 1
because there may be a region where a large amount or a small amount of light is randomly irradiated due to a large energy per photon of EUV light, which may be referred to as a photo shot noise, or an EUV absorption difference between top and bottom of the photoresist may cause pattern dispersion deterioration
Data Source
AI summary
Provided are a resist topcoat composition and a method of forming patterns using the resist topcoat composition, the resist topcoat composition including a copolymer including a first structural unit represented by Chemical Formula M-1, a second structural unit represented by Chemical Formula M-2; at least one acidic compound selected from a sulfonic acid compound containing at least one fluorine, a sulfonimide compound containing at least one fluorine, and a carboxylic acid compound containing at least one fluorine; and a solvent.