Lithography Module Timing Control Without Master Clock Sync
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Solution Overview
Problem
Current charged particle lithography systems face challenges in achieving precise synchronization of operations across modules, particularly as the patterning resolution increases and the number of charged particle beamlets grows, requiring more complex and costly solutions for clock synchronization.
Innovation Solution
A method and system that utilize two distinct time bases, where one time base is generated based on a clock signal and used to determine a sync value, allowing for the initialization of operations in modules without needing synchronization with a common time base, enabling precise coordination of operations across modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If clock circuits in controller and subsystems are synchronized using prior art methods, then operations can be coordinated, but the system becomes more complex and costly as accuracy requirements increase
Solution Approach 1:
The patent divides the synchronization system into independent segments: each subsystem maintains its own local clock circuit and time base without requiring synchronization with a master clock. The controller and subsystems independently determine their respective sync values and convert start times without inter-dependent clock synchronization, eliminating the need for complex master-slave clock networks.
Solution Approach 2:
The patent introduces a time base conversion mechanism as an intermediary that translates start times from the controller's time base to the subsystem's time base using predetermined conversion relationships. This intermediary conversion process enables accurate operation coordination without direct clock synchronization between controller and subsystems.
2Manufacturing precision
If patterning resolution increases and number of beamlets increases, then lithography precision improves, but the required precision of synchronization becomes greater requiring more complex solutions
Solution Approach 1:
The patent changes the synchronization approach from time-based clock synchronization to parameter-based time base conversion. By using predetermined conversion relationships between time bases and converting start times through these parameters, the system achieves the required high synchronization precision for multi-beamlet operations without increasing system complexity.
3Measurement precision
If complex and costly synchronization solutions are implemented, then synchronization accuracy improves, but system cost and complexity increase
Solution Approach 1:
Each subsystem independently determines its own sync value based on its local clock circuit and time base, then independently converts the controller's start time to its local time base using predetermined conversion relationships. This self-service approach eliminates the need for expensive master clock distribution systems and complex synchronization hardware.
Data Source
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AI summary
A method for initializing a first operation in a first module (120) at a first start time value in a first time base, the method comprising generating a clock signal (402, 116), generating a second time base (403) in the first module (120) based on the clock signal (116), determining a second sync value (405) in the second time base, determining a first sync value (406) in the first time base corresponding to a second sync value in the second time base, determining a start trigger value (410) in the second time base based on the first sync value and the start time value in the first time base, and initializing the first operation (411) in the first module (120) based on the start trigger value and a current value of the second time base in the first module.