Charged Particle Beam Inspection Using Overlapping Frames
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Solution Overview
Problem
Current pattern inspection methods for semiconductor wafers face challenges in achieving high accuracy and efficiency due to the miniaturization of patterns, leading to increased settling time and potential false defect detection caused by differences in electron beam characteristics.
Innovation Solution
A charged particle beam inspection method where multiple scanning areas are inspected using different charged particle beams while the stage is moved, allowing for overlapping inspection frames and beam margins to reduce positional and brightness differences, thereby improving defect detection accuracy and reducing unnecessary scanning time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple electron beams are used to scan different areas simultaneously, then productivity is improved, but reliability deteriorates due to characteristic differences between beams causing false defect detection
Solution Approach 1:
The patent assigns different scanning strategies to different beam scanning areas based on their specific characteristics. Beam scanning areas are divided into first and second types, with the first type using conventional scanning and the second type using scanning with beam margins and overlapping frames. This local differentiation allows the system to maintain high productivity while compensating for beam characteristic variations in specific areas through enhanced scanning parameters.
2Productivity
If step-and-repeat operation is used with multiple beams, then productivity is improved, but loss of time increases due to settling time required for each stage movement
Solution Approach 1:
The patent implements continuous stage movement throughout the inspection process, eliminating the stop-and-go nature of conventional step-and-repeat operations. The stage moves continuously while multiple beams scan different areas, and beam margins with overlapping frames ensure that scanning is maintained without interruption during transitions. This continuous operation eliminates settling time between steps while maintaining comprehensive coverage through the overlapping scanning strategy.
3Productivity
If conventional scanning is used without beam margins, then productivity is maintained, but measurement precision deteriorates due to positional differences between beams
Solution Approach 1:
The patent introduces beam margins that extend beyond the nominal scanning area boundaries before actual scanning begins. These margins are prepared in advance and create overlapping regions between adjacent beam scanning areas. The overlapping frames within these margins allow for preliminary alignment and characterization of beam positions, enabling the system to compensate for positional variations while maintaining continuous scanning operation.
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 method enhances defect detection accuracy by minimizing false defects and reducing scanning time through overlapping inspection frames and beam margins, effectively addressing the challenges of miniaturization and characteristic differences among electron beams.
Implementation Method 1
detects secondary electrons corresponding to the respective beams emitted from inspection object substrate to obtain a pattern image
Data Source
AI summary
A charged particle beam inspection method conducted by disposing a sample on a stage and by performing a first scanning in a first beam scanning area on the sample by using one first charged particle beam out of a plurality of charged particle beams while the stage is moved so that a first inspection of a first inspection unit in the first beam scanning area is performed, and by performing a second scanning in a second beam scanning area on the sample by using one second charged particle beam out of the charged particle beams while the stage is moved so that a second inspection of a second inspection unit in the second beam scanning area is performed.