EUV Metallic Resist Humidity Control for Uniform Sub-20nm Patterning
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Solution Overview
Problem
Conventional polymer-based photoresists suffer from low absorption efficiency to EUV radiation, leading to resolution issues and reduced throughput in EUV lithography due to decreased photo flux, resulting in line width roughness and critical dimension non-uniformity as semiconductor device sizes shrink below 20 nanometers.
Innovation Solution
Introducing water or humidity into the EUV lithography process to facilitate hydrolysis and condensation of organometallic compounds, which form insoluble metal oxide clusters upon radiation exposure, enhancing resist sensitivity and throughput by using organometallic compounds with metallic cores and organic ligands in the photoresist layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polymer-based photoresists are used in EUV lithography, then the photoresist layer can be formed, but the absorption efficiency to EUV radiation is low, resulting in resolution issues and line width roughness
Solution Approach 1:
The patent changes the chemical composition parameters of the photoresist by replacing conventional polymer-based materials with organometallic compounds containing metallic cores (Sn, Hf, Zr, Ag, Cd, In, Sb, Te, Cs, Au, Ba, Tl, Bi, or Ce). This material substitution fundamentally alters the absorption characteristics, enabling high EUV radiation absorption efficiency while maintaining manufacturing precision for sub-20nm features
Solution Approach 2:
The patent employs composite organometallic compounds consisting of metallic cores coordinated with organic ligands (carboxylates, phosphines, phosphonates, amines, or alkyl groups). This composite structure combines the high EUV absorption capability of metal atoms with the processability and film-forming properties of organic molecules, achieving both high absorption efficiency and manufacturing precision
2Productivity
If conventional polymer-based photoresists are used, then the photoresist layer can be processed, but the throughput is reduced due to decreased photo flux and line width roughness
Solution Approach 1:
The patent modifies the photoresist composition to organometallic compounds that exhibit enhanced sensitivity to EUV radiation, reducing the required exposure dose and processing time. The metallic cores provide high absorption cross-sections, enabling faster patterning and improved throughput while maintaining pattern quality
Solution Approach 2:
The patent introduces water or humidity (55-100% relative humidity) during the baking process before EUV exposure to pre-hydrolyze the organometallic compounds. This preliminary hydrolysis creates metal oxide clusters that enhance the subsequent radiation response, improving both throughput and pattern fidelity
3Productivity
If device sizes are scaled down below 20 nanometers, then production efficiency increases, but line width roughness and critical dimension non-uniformity increase
Solution Approach 1:
The patent changes the material composition to organometallic compounds with metallic cores that provide high EUV absorption efficiency, enabling precise patterning at sub-20nm scales. The uniform atomic structure of metal centers ensures consistent radiation response across the pattern, maintaining critical dimension uniformity while enabling smaller feature sizes
Solution Approach 2:
The patent applies preliminary hydrolysis treatment by controlling humidity (55-100% RH) during baking to form uniform metal oxide clusters throughout the photoresist layer before exposure. This pre-treatment ensures homogeneous radiation response and reduces line width roughness, enabling high-precision patterning at scaled dimensions
4Reliability
If water or humidity is introduced to facilitate hydrolysis of organometallic compounds, then resist sensitivity increases, but the baking process conditions must be precisely controlled
Solution Approach 1:
The patent optimizes the water content parameter within a specific range (55-100% relative humidity during baking) to achieve sufficient hydrolysis of organometallic compounds without causing excessive aggregation or solubility issues. This controlled parameter range ensures high resist sensitivity while maintaining process robustness
Solution Approach 2:
The patent implements feedback control by monitoring and adjusting humidity levels during the baking process to maintain the optimal 55-100% RH range. This feedback mechanism ensures consistent hydrolysis程度 and metal oxide cluster formation, achieving high resist sensitivity while managing process complexity through active control
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
Improves EUV lithography performance and throughput by increasing resist sensitivity, reducing line width roughness, and achieving better critical dimension uniformity, with the water content optimized to maintain humidity levels between 55% to 100% during baking and exposure processes.
Implementation Method 1
Introducing water or humidity into the EUV lithography process to facilitate hydrolysis and condensation of organometallic compounds
Implementation Method 2
facilitate hydrolysis and condensation of organometallic compounds, which form insoluble metal oxide clusters upon radiation exposure
Implementation Method 3
which form insoluble metal oxide clusters upon radiation exposure
Data Source
AI summary
A method for forming a semiconductor device is provided. The method includes applying a photoresist composition over a substrate, thereby forming a photoresist layer over the substrate; performing a first baking process to the photoresist layer; exposing the photoresist layer to an extreme ultraviolet (EUV) radiation, thereby forming a pattern therein; performing a second baking process to the photoresist layer; and developing the photoresist layer having the pattern therein using a developer, thereby forming a patterned photoresist layer. The first baking process and the second baking process are conducted under an ambient atmosphere having a humidity level ranging from 55% to 100%.