DAC Amplifier Dynamic Diagnosis for Charged Particle Beam Writing
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Solution Overview
Problem
Current methods for diagnosing DAC amplifier units in charged particle beam writing apparatuses are insufficient as they only test static characteristics, failing to detect errors at high data transfer rates, which can lead to prolonged downtime due to undetected dynamic failures.
Innovation Solution
A method and apparatus that transmit and store digital data at the same rate as writing on a product reticle, comparing the first and second digital data for each bit to diagnose the digital section of the DAC amplifier unit, enabling the diagnosis of dynamic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the data transfer rate between deflection control circuit and DAC amplifier unit is increased to improve writing throughput, then productivity is improved, but the likelihood of errors in the digital section increases
Solution Approach 1:
The patent implements preliminary diagnosis actions by transmitting test digital data through the DAC amplifier unit before actual writing operations. The diagnosis unit compares input and output digital data to detect errors in advance, allowing the system to identify and address potential failures before they affect production writing throughput and reliability
Solution Approach 2:
The patent establishes a feedback mechanism where the diagnosis unit continuously monitors the digital section by comparing original digital data with output digital data from the DAC amplifier unit. This feedback loop enables real-time detection of errors and allows the system to adjust operations to maintain reliability at high data transfer rates
2Manufacturing precision
If conventional linearity test methods are used to diagnose DAC amplifier unit, then manufacturing precision is maintained, but dynamic characteristics cannot be detected
Solution Approach 1:
The patent transitions from static linearity testing to dynamic diagnosis by transmitting digital data at the actual writing rate through the DAC amplifier unit. This dynamic testing approach enables detection of errors that occur only under high-speed operating conditions, complementing traditional linearity tests to provide comprehensive diagnosis
Solution Approach 2:
The patent changes the testing parameter from static analog voltage measurement to dynamic digital data transmission at writing rate. By altering the test conditions to match actual operating parameters, the system can detect dynamic errors that static linearity tests cannot identify, while maintaining confidence in manufacturing precision
3Device complexity
If diagnosis of DAC amplifier unit is not performed at actual writing rate, then device complexity is reduced, but failure location cannot be specified
Solution Approach 1:
The patent implements a self-diagnosis capability where the DAC amplifier unit's own digital section processes and compares digital data to identify internal errors. This self-service approach enables the system to automatically specify failure locations without requiring complex external diagnosis equipment, maintaining simplicity while improving repairability
Data Source
AI summary
The charged particle beam writing apparatus includes a position deflection control circuit. First digital data that is to be used for circuit diagnosis is transmitted from the position deflection control circuit to the DAC amplifier unit at the same rate as a rate of writing on a product reticle and stored in a first maintenance memory. Second digital data is output from a digital section included in the DAC amplifier unit in response to the first digital data and stored in a second maintenance memory. A maintenance clock generator generates a clock signal and reads the first digital data stored in the first maintenance memory and the second digital data stored in the second maintenance memory. The first digital data thus read is compared with the second digital data thus read for each bit to diagnose the digital section.