Electrostatic Holder Edge Gap for Dust-Controlled Lithography
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Solution Overview
Problem
Dust particles from within a lithographic apparatus contaminate substrates during EUV radiation illumination due to imperfect vacuum conditions, leading to defects in integrated circuits.
Innovation Solution
An electrostatic holder with a clamping element and a body that creates a gap between the outer edge and the clamped object, allowing a fluid to be outputted to reduce dust particle contamination, utilizing a gas supply system and pressure equalizing chamber to manage fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a perfect vacuum is maintained in the lithographic apparatus, then dust particle contamination is eliminated, but the complexity and cost of the vacuum system increases significantly
Solution Approach 1:
The invention extracts the harmful dust particles from the system by introducing a gas flow that actively removes particles from the vicinity of the substrate and holder, rather than relying solely on maintaining a perfect vacuum throughout the entire apparatus
Solution Approach 2:
A gas flow is introduced as an intermediary medium to interact with dust particles, carrying them away from critical areas. This gas flow acts as a mediator between the vacuum environment and particle contamination control
2Object-affected harmful factors
If gas flow is introduced to reduce dust particles, then particle contamination is reduced, but the vacuum conditions are compromised
Solution Approach 1:
The gas flow is applied locally around the holder and substrate area rather than throughout the entire apparatus. This localized application creates a particle-free zone where needed while maintaining vacuum conditions in the rest of the system
Solution Approach 2:
The vacuum environment is segmented into different zones: a localized region around the holder/substrate where gas flow is applied for particle removal, and the rest of the apparatus where vacuum conditions are maintained
3Object-affected harmful factors
If the holder structure is made more complex to reduce dust particles, then particle contamination is reduced, but the manufacturing complexity increases
Solution Approach 1:
The invention uses pneumatic means (gas flow) to achieve particle reduction instead of complex mechanical structures. The gas delivery system uses simple channels and openings that can be easily manufactured into the holder body
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 minimizes dust particle contamination on substrates by maintaining a controlled fluid flow, enhancing the precision and functionality of integrated circuit production.
Implementation Method 1
a clamping element (24) attached to the body (21), wherein the clamping element (24) comprises an electrode (26) for applying the attractive force between the clamping element (24) and the object (W)
Implementation Method 2
an outer edge (31) of the body (21) configured to provide a gap (GA) between the outer edge (31) of the body (21) and the object (W), wherein the gap (GA) is configured for outputting a fluid for reducing dust particles reaching the object (W)
Data Source
AI summary
The invention relates to an electrostatic holder comprising: a body, and a clamping element attached to the body, said clamping element comprising an electrode for applying an attractive force between the clamping element and a first to be clamped object, wherein an outer edge of the body is configured to provide a gap between the outer edge of the body and the first to be clamped object, which gap is configured for outputting a fluid for reducing dust particles reaching the first to be clamped object or a second to be clamped object on an opposite side of the holder.