Immersion Post-Exposure Bake EUV Lithography Process
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Solution Overview
Problem
The insufficient power of EUV light sources in EUV lithography leads to low throughput in manufacturing, especially for high-resolution applications, and current efforts to improve photoresist performance often degrade other lithography metrics such as line edge roughness, critical dimension uniformity, and resolution, while also raising contamination concerns.
Innovation Solution
Applying a protic solvent, such as water, to the EUV photoresist layer after exposure to EUV radiation and heating it in an immersion post-exposure bake process to generate more protons for deprotection, thereby reducing the need for EUV irradiation and increasing throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If EUV light source power is increased to improve throughput, then manufacturing throughput increases, but light source complexity and cost increase
Solution Approach 1:
A protic solvent is introduced as an intermediary substance between the EUV light source and the photoresist layer. The solvent absorbs EUV radiation and generates protons that catalyze the deprotection reaction, acting as a mediator that amplifies the effective exposure dose without requiring increased light source power. This resolves the contradiction by enabling higher throughput through chemical amplification rather than physical power increase.
Solution Approach 2:
The invention changes the chemical parameters of the photoresist system by incorporating protic solvent-responsive groups that undergo deprotection upon protonation. This parameter change in the photoresist chemistry enables enhanced sensitivity and throughput without modifying the light source, thereby resolving the contradiction between throughput and light source complexity.
2Productivity
If exposure time is reduced to increase throughput, then manufacturing throughput increases, but photoresist deprotection completeness deteriorates
Solution Approach 1:
The photoresist is pre-engineered with protic solvent-responsive deprotecting groups that are designed to rapidly deprotect upon contact with protic solvents. This preliminary chemical design enables the deprotection reaction to proceed quickly and completely even with reduced EUV exposure time, thereby resolving the contradiction between throughput and deprotection completeness.
Solution Approach 2:
The protic solvent serves as a chemical intermediary that transfers protons to the photoresist deprotecting groups, accelerating the deprotection reaction kinetics. This intermediary mechanism enables complete deprotection to occur rapidly, allowing reduced exposure times while maintaining deprotection completeness, thus resolving the throughput-precision contradiction.
3Device complexity
If conventional photoresist materials are used to maintain simplicity, then process complexity remains low, but contamination risk increases
Solution Approach 1:
The invention changes the material composition parameter by developing photoresist materials containing protic solvent-responsive deprotecting groups that eliminate metal catalysts. This parameter change in material chemistry removes the source of metal contamination while maintaining process simplicity, thereby resolving the contradiction between process complexity and contamination risk.
4Manufacturing precision
If multiple patterning processes are used to achieve fine pitch, then resolution improves, but process complexity increases
Solution Approach 1:
The invention uses composite photoresist materials that combine protic solvent-responsive deprotecting groups with appropriate polymer matrices. This composite material design enables single-step patterning at fine pitches by enhancing the chemical amplification efficiency, thereby achieving high resolution without the complexity of multiple patterning processes.
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 enhances the efficiency of the EUV lithography process by allowing shorter exposure times and higher throughput without degrading other performance metrics, and eliminates the risk of metal contamination.
Implementation Method 1
Applying a protic solvent, such as water, to the EUV photoresist layer after exposure to EUV radiation and heating it in an immersion post-exposure bake process to generate more protons for deprotection
Implementation Method 2
heating the protic solvent on the EUV photoresist layer to a post-exposure bake temperature
Data Source
AI summary
A method of performing extreme ultraviolet lithography process includes applying a protic solvent over an extreme ultraviolet (EUV) photoresist layer located over a substrate after exposure to EUV radiation, heating the protic solvent on the EUV photoresist layer to a post-exposure bake temperature photoresist, and removing the protic solvent from above the EUV photoresist layer prior to developing the EUV photoresist layer.