Reticle Holder Assembly for EUV Mask Blank Processing
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Solution Overview
Problem
Conventional EUV mask blank processing systems face challenges in controlling defects and achieving zero flatness in carrier bases, leading to particle generation and non-uniform deposition during handling and processing of EUV mask blanks.
Innovation Solution
A reticle processing system with a support assembly and a carrier base assembly that includes a containment region with a peripheral rim to minimize contact and friction, and the use of pins to vertically separate components, reducing particle accumulation and ensuring uniform deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a carrier base is used to hold the reticle during processing, then the reticle can be transported and positioned, but the carrier base generates particles due to friction and slippage on the pedestal
Solution Approach 1:
The patent removes the carrier base entirely from the system. Instead of using a traditional carrier base that contacts the pedestal, the reticle is held directly by a reticle holder assembly that can be positioned and secured without a separate carrier base, thereby eliminating the source of particle generation from carrier base friction and slippage
Solution Approach 2:
The patent introduces a reticle holder assembly as an intermediary component between the reticle and the pedestal. This holder assembly includes a reticle holder and reticle support structure that can be precisely positioned and secured, providing the necessary function of holding and transporting the reticle without the friction and slippage problems of a carrier base on a pedestal
2Object-affected harmful factors
If a carrier top shield is mounted at a higher level than the reticle to prevent deposition on the carrier base, then material deposition is prevented, but particles may fall on the reticle after deposition causing edge roll effect
Solution Approach 1:
The patent eliminates the carrier top shield entirely. Instead of using a shield mounted above the reticle, the system uses a reticle holder assembly with a reticle holder and support structure that provides both deposition prevention and particle contamination prevention through its integrated design, removing the source of particle falling onto the reticle
Solution Approach 2:
The patent combines the functions of the carrier top shield and carrier base into a single integrated reticle holder assembly. This merged structure provides both the deposition prevention function and the particle contamination prevention function through its unified design, eliminating the need for separate components that could generate particles
3Measurement precision
If the carrier base is machined aluminum with multiple pockets for camera inspection and machining, then alignment and detection are enabled, but the pockets become potential sources for particle passage during carrier base slippage
Solution Approach 1:
The patent removes the carrier base with its problematic pockets entirely. Instead, the reticle holder assembly provides alignment and detection capabilities through its own integrated features, eliminating the pockets that served as particle passages during carrier base slippage
Solution Approach 2:
The reticle holder assembly acts as an intermediary that provides the necessary alignment and detection functions without relying on pockets. The holder assembly includes features for camera inspection and alignment that do not create open pathways for particle passage, thus maintaining measurement precision while preventing particle contamination
Data Source
AI summary
Provided herein are apparatus, systems and methods for processing reticle blanks. A reticle processing system includes a support assembly having a plate coupled to a frame, and a carrier base assembly supported on the support assembly. The carrier base assembly comprises a wall extending from a top surface of the carrier base and defining a containment region for a reticle.