Dual Plasma Source for Lithography Aperture Cleaning
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Solution Overview
Problem
Charged particle lithography systems are hindered by contaminant deposits, particularly carbon-containing layers formed through Electron Beam Induced Deposition (EBID), which reduce aperture sizes and beam transmission, necessitating an effective method for removal, especially in areas with high hydrocarbon partial pressures and beam current densities.
Innovation Solution
A dual plasma source design comprising a primary plasma source and a secondary plasma source, where the primary source generates plasma that is guided through a hollow body to the secondary source, enhancing plasma generation and stability, allowing for efficient production and delivery of atomic radicals for cleaning, even in restricted spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single high-power plasma source is used to generate sufficient atomic radicals for cleaning, then cleaning effectiveness is improved, but device complexity and power consumption increase
Solution Approach 1:
The plasma source is divided into two separate plasma sources: a first plasma source that generates plasma and atomic radicals, and a second plasma source that further processes the plasma. This segmentation allows each source to operate at lower power individually while achieving the cleaning effectiveness of a single high-power source through their combined action.
Solution Approach 2:
The patent combines the functions of two plasma sources working in sequence - the first source generates plasma and atomic radicals, and the second source enhances the plasma generation. By merging their effects, the system achieves high cleaning productivity while each individual source operates with reduced complexity and power requirements.
2Ease of operation
If plasma is generated in a remote location and transported through a long path, then access to restricted areas is improved, but radical loss during transport increases
Solution Approach 1:
The first plasma source is positioned to generate plasma and atomic radicals in advance, creating a plasma flow that is then guided through the hollow guiding body to the second plasma source and ultimately to the restricted area. This preliminary generation of plasma allows the system to reach restricted areas while minimizing the distance radicals need to travel without being generated.
Solution Approach 2:
The hollow guiding body acts as an intermediary structure that channels and directs the plasma flow from the first plasma source to the second plasma source and then to the cleaning location. This intermediary pathway enables access to restricted areas while maintaining plasma integrity and reducing radical loss during transport.
3Productivity
If a second plasma source is added to enhance plasma generation, then cleaning efficiency is improved, but device complexity increases
Solution Approach 1:
The second plasma source serves multiple functions: it enhances plasma generation from the first source, stabilizes the plasma flow, and positions the plasma precisely at the cleaning location. By giving the second source these multiple functions, the system achieves improved cleaning efficiency while justifying the added component through its versatile role.
Solution Approach 2:
The second plasma source is strategically positioned to provide localized plasma enhancement exactly where needed - at the outlet end of the hollow guiding body where the plasma is delivered to the cleaning location. This local quality enhancement allows efficient cleaning without requiring the entire system to be upgraded to high complexity.
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 design enables effective cleaning of contaminant deposits with reduced power consumption and increased efficiency, achieving high cleaning rates while minimizing radical loss during transport, and can be implemented in areas with limited access, such as beam stop and aperture arrays in lithography systems.
Implementation Method 1
a first coil for generating the plasma in the primary source chamber
Implementation Method 2
produce a stream of atomic radicals that chemically react with the deposits, forming volatile molecular compounds
Data Source
AI summary
An arrangement for generating plasma, the arrangement comprising a primary plasma source (1) comprising a primary source chamber (15) and a first coil (4) for generating plasma in the primary source chamber, a secondary plasma source (25) comprising a secondary source chamber (16) and a second coil (26) for enhancing plasma generated by the primary plasma source and/or generating plasma in the secondary source chamber generating plasma in the primary source chamber, a hollow guiding body (11) arranged for guiding at least a portion of the plasma generated by the primary plasma source to the secondary plasma source, and an outlet (14) for emitting at least a portion of the plasma generated by the arrangement.