Multiple Electron Beam Irradiation Apparatus Defect Compensation
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Solution Overview
Problem
Multiple electron beam irradiation systems face challenges due to defective beams, which can lead to incomplete inspections or pattern defects in semiconductor manufacturing, as a single defective beam among many can render the entire system unusable, affecting the accuracy and efficiency of pattern inspection and writing processes.
Innovation Solution
The system employs a method to identify and manage defective beams by setting frame regions for irradiation, using normal beams to bypass or compensate for defective ones, allowing for continued accurate inspection and writing processes by adjusting the irradiation patterns and beam control mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple electron beams are used for inspection, then inspection speed and throughput are improved, but the system becomes vulnerable to defective beams that can render the entire system unusable
Solution Approach 1:
The patent divides the inspection field into multiple frame regions and assigns different beam sets to different regions. When a defective beam is detected, only the regions affected by that beam need to be re-inspected by alternative beams, rather than requiring the entire inspection system to stop. This segmentation allows the system to maintain high productivity while improving reliability through localized recovery.
Solution Approach 2:
The patent dynamically changes beam parameters (which beams are active) based on detected defects. When a defective beam is identified, the system switches to using different beams for inspection, changing the operational parameters of the beam system to maintain functionality. This allows continuous operation with modified beam configurations.
2Measurement precision
If a defective beam is detected, then inspection accuracy is maintained by excluding the defective beam, but inspection time increases due to re-inspection requirements
Solution Approach 1:
The patent performs preliminary detection of defective beams using a test pattern before actual inspection. By identifying and excluding defective beams in advance, the system prevents re-inspection delays during production inspection. The frame region division also allows preliminary identification of which specific regions need alternative inspection, minimizing the time impact.
Solution Approach 2:
By dividing the inspection area into frame regions and tracking which beams cover which regions, the system can selectively re-inspect only the affected regions rather than the entire wafer. This segmentation dramatically reduces the time penalty for handling defective beams.
3Measurement precision
If the system waits for defective beam correction before resuming inspection, then inspection accuracy is preserved, but manufacturing yield decreases due to downtime
Solution Approach 1:
The patent introduces alternative beams as intermediaries to replace defective beams during inspection. Instead of waiting for the defective beam to be corrected, the system uses other functional beams to perform the inspection of affected regions. This intermediary approach maintains inspection accuracy while avoiding production downtime.
Solution Approach 2:
The system maintains continuous inspection operation by switching to alternative beams when defects are detected. The useful action of inspection continues without interruption, only the specific beams used change. This ensures both accuracy is maintained and manufacturing yield is preserved through uninterrupted production.
4Area of stationary object
If all beams are used for inspection, then inspection coverage is maximized, but the impact of a single defective beam becomes critical
Solution Approach 1:
The patent implements dynamic beam assignment where the set of active beams changes based on detected defects. The system starts with all beams for maximum coverage, but dynamically adjusts by excluding defective beams and reassigning regions to alternative beams. This dynamic adaptation maintains both coverage and robustness simultaneously.
Solution Approach 2:
Different regions of the inspection field are assigned different beam sets based on local beam availability and quality. When a beam is defective, only the local regions it covers are reassigned to alternative beams, while other regions continue using their original beams. This local quality approach maintains overall system robustness while preserving inspection coverage.
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 ensures that even with defective beams present, the system can maintain desired accuracy and speed in inspections and writing operations, reducing downtime and improving manufacturing yield by effectively utilizing remaining functional beams.
Implementation Method 1
acquires a pattern image by scanning the inspection substrate with electron beams and detecting secondary electrons emitted from the inspection substrate by the irradiation with the electron beams
Data Source
AI summary
A multiple electron beam irradiation apparatus includes a first region setting circuit which sets a first frame region of a plurality of first frame regions which can be irradiated with remaining beams after excluding beams in one row and one column at end; a second region setting circuit which sets a second frame region of a plurality of second frame regions each having four corners equivalent to an irradiation position of the defective beam by using normal beams; and an electron beam irradiation mechanism which performs the first multiple electron beam irradiation processing for the each of the plurality of first frame regions of the target object by using the normal beams, and perform second multiple electron beam irradiation processing for each of the plurality of second frame regions by using at least beams at the four corners.