Spectral Purity Filter Gas Flow Support UV Lithography
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Solution Overview
Problem
Spectral purity filters in UV lithography systems face challenges in achieving high transmission efficiency due to the limited strength of thin film materials, which restricts filter size and is exacerbated by the use of mesh support structures that reduce transmission efficiency further.
Innovation Solution
A spectral purity filter arrangement that uses a thin film supported by a gas flow system along one edge, eliminating the need for mesh and maximizing transmission efficiency by providing mechanical and gas flow support, allowing for larger filter sizes without disrupting laminar light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If mesh support structures are used to support the thin film material, then larger filter sizes can be achieved, but transmission efficiency is reduced due to light blockage by the mesh material
Solution Approach 1:
The patent removes the mesh support structure from the filter assembly, extracting the problematic element that blocked light. Instead, the thin film is supported by a frame without requiring a mesh overlay, eliminating the trade-off between support and transmission efficiency
Solution Approach 2:
The patent introduces a frame structure as an intermediary support mechanism that holds the thin film at its periphery without requiring additional support across the film surface. This frame acts as a mediator that provides mechanical support while leaving the transmission path clear
2Loss of energy
If the thin film material is made thinner to improve transmission efficiency, then more in-band radiation passes through, but mechanical strength is reduced limiting filter size
Solution Approach 1:
The patent applies different structural qualities to different parts of the filter assembly: the thin film maintains its thinness for optimal transmission in the active filtering area, while the frame structure provides concentrated mechanical support at the periphery where strength is needed but light transmission is not required
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
The gas flow support system enhances the mechanical stability and transmission efficiency of spectral purity filters, enabling larger filter sizes without reducing the passage of in-band radiation, thus improving the overall performance in UV lithography systems.
Implementation Method 1
at least a first gas port configured to provide gas flow support for the film
Implementation Method 2
a spectral purity filter made of a material that permits light of certain wavelengths to pass through while blocking light of other wavelengths
Data Source
AI summary
A spectral purity filter arrangement is disclosed. The spectral purity filter arrangement includes a film configured for filtering out at least a portion of input light and a support structure coupled to the film along at least one edge of the film. The spectral purity filter arrangement further includes a gas control subsystem configured to direct a gas at the film to support the film at least when the film is disposed in an operational position to perform the filtering.