Charged Particle Beam Lithography Data Inspection for Dose Control
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Solution Overview
Problem
In semiconductor manufacturing, charged particle beam lithography systems face issues with abnormal dose irradiation due to incorrect user input or correction tool settings, leading to pattern dimension abnormalities and potential lithography apparatus contamination.
Innovation Solution
An inspection method and apparatus that create an area map of figure patterns modulated by dose rates, converting layout data into pattern writing data, and inspecting electric charge amounts in predetermined regions to ensure compliance with thresholds, preventing abnormal dose irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dose modulation is performed based on user input or correction tool settings, then pattern writing flexibility is improved, but risk of abnormal dose irradiation increases
Solution Approach 1:
The patent performs preliminary inspection of pattern writing data before actual lithography execution. The inspection apparatus checks whether dose values in the pattern writing data fall within predetermined acceptable ranges, and identifies regions where cumulative dose may exceed thresholds. This preliminary validation prevents abnormal dose irradiation while preserving the flexibility of dose modulation approaches.
2Productivity
If high dose is used for pattern writing, then writing speed is improved, but pattern dimension control deteriorates
Solution Approach 1:
The patent applies local quality control by inspecting dose values and cumulative dose separately for different regions (shots) of the pattern writing data. The system identifies specific shots where cumulative dose exceeds predetermined thresholds and flags only those regions for correction, while allowing other regions to proceed with their intended high-dose writing parameters. This maintains writing speed in acceptable regions while ensuring precision in critical regions.
3Productivity
If multiple shots are combined for pattern writing, then efficiency is improved, but cumulative dose control becomes difficult
Solution Approach 1:
The patent implements feedback control by calculating cumulative dose for each shot based on previously written patterns, comparing the cumulative dose against predetermined thresholds, and providing feedback information to identify shots that exceed acceptable levels. This automated feedback mechanism manages the complexity of multi-shot cumulative dose control while maintaining writing efficiency.
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 approach effectively prevents abnormal dose irradiation, avoiding pattern dimension errors and lithography apparatus contamination by inspecting and validating electric charge amounts in real-time, ensuring accurate and reliable pattern writing.
Implementation Method 1
a charged particle beam writing unit configured to write a pattern on a target object based on the pattern writing data
Data Source
AI summary
An inspection method of pattern writing data includes creating an area map of a figure pattern written on a target object for each modulation rate for modulating a dose by using modulation rate data to modulate the dose in a case that a plurality of figure patterns is written on the target object by using a charged particle beam, and layout data in which the plurality of figure patterns is defined; converting the layout data into pattern writing data to be input into a lithography apparatus; and inspecting an amount of electric charge for each predetermined region by using the area map when a pattern is written on the target object by using the pattern writing data.