EUV Contamination Reduction via Electrode Electric Field Steering
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Solution Overview
Problem
Extreme ultraviolet (EUV) radiation in lithographic apparatuses generates contamination through plasma interactions, leading to defective products and increased maintenance needs due to contaminant particles being attracted to sensitive optical surfaces.
Innovation Solution
A contamination reduction system with an electrode positioned between a shutter and a patterning system, generating an electric field to steer charged contaminants away from the patterning system, using a low voltage to prevent arcs and minimize volume requirements, and optionally incorporating a gas curtain and cooling system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If EUV radiation power is increased to improve lithographic patterning capability, then manufacturing precision is improved, but contamination generation increases
Solution Approach 1:
The patent converts the harmful plasma environment and charged particles into a beneficial tool by using the same plasma-generated charged particles to clean the substrate surface. The plasma treatment that would normally cause contamination is instead used to remove contaminants, transforming the harmful effect into a useful cleaning mechanism
Solution Approach 2:
The patent introduces a gas curtain as an intermediary barrier between the EUV radiation source and the substrate. This gas curtain absorbs and redirects charged particles before they can reach and contaminate the substrate, while allowing the beneficial EUV radiation to pass through and perform patterning
2Reliability
If a contamination reduction system is added to protect the patterning system, then reliability is improved, but device complexity increases
Solution Approach 1:
The gas curtain serves multiple functions simultaneously: it acts as a physical barrier to block contaminants, generates plasma for surface cleaning, and maintains the vacuum environment. This multi-functionality reduces the need for separate contamination reduction devices, thereby limiting the increase in device complexity
Solution Approach 2:
The patent changes the physical state and parameters of the gas curtain (pressure, flow rate, composition) to optimize its contamination reduction effectiveness. By dynamically adjusting these parameters, the system achieves reliable protection without requiring complex mechanical structures
3Manufacturing precision
If an electrode is positioned close to the patterning system to effectively steer particles, then contamination reduction effectiveness is improved, but the risk of arcs increases
Solution Approach 1:
The gas curtain acts as an intermediary medium between the electrode and the substrate, providing electrical insulation that prevents arc discharge while allowing the electric field to effectively steer charged particles away from the substrate. This mediator enables close positioning of the electrode without increasing arc risk
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
Effectively reduces contamination on patterning systems in plasma environments by diverting charged particles away from sensitive surfaces, enhancing product quality and reducing maintenance, while maintaining safety and efficiency.
Implementation Method 1
an electrode positioned between the shutter and the support, the electrode connected to a voltage source and configured to generate an electric field between the electrode and the patterning system held by the support. The electric field is such that at least one charged particle between the electrode and the patterning system is attracted by the electrode. The electric field is such that at least at least one charged particle is steered away from the patterning system.
Implementation Method 2
a shutter configured to shield a portion of the radiation beam from the patterning system
Implementation Method 3
the EUV radiation may interact with matter present in the lithographic apparatus (e.g. small amounts of gas) to form a plasma. The plasma may provide suitably strong electrostatic force to release contaminant particles from surfaces within the lithographic apparatus.
Data Source
AI summary
A contamination reduction system for reducing contamination of a patterning system in a plasma environment, comprising: a support arranged to hold a patterning system in a radiation beam; a shutter configured to shield a portion of the radiation beam from the patterning system; and an electrode positioned between the shutter and the support, the electrode connected to a voltage source and configured to generate an electric field between the electrode and the patterning system held by the support.