Multi-beam Writing Apparatus Vibration Detection
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Solution Overview
Problem
Multi-beam writing apparatuses face challenges in detecting electron beam vibration due to the low intensity of electrons reflected from calibration marks, making it difficult to evaluate beam direction and cause of vibration, as traditional methods are not applicable for multiple beams.
Innovation Solution
A multi-charged-particle-beam writing apparatus is designed with a shaping aperture array plate, a blanking aperture array plate, an inspection aperture plate, a current detector, and a deflector, which allows for the measurement and evaluation of beam vibration by detecting the current of one beam passing through a specific aperture, enabling precise beam position calculation and vibration analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple beams are applied to a large irradiation area, then throughput is increased, but the ability to detect beam vibration is lost because reflected electron intensity becomes too low
Solution Approach 1:
The patent segments the multiple beams into individual detectable units by using a beam selector to isolate one beam at a time for vibration measurement. This allows the system to maintain multi-beam operation for high throughput while periodically selecting individual beams for precise vibration detection through the aperture and electron detector system.
2Measurement precision
If traditional electron reflection detection method is used, then beam vibration can be detected in single-beam apparatus, but the method becomes ineffective in multi-beam apparatus due to low reflected electron intensity
Solution Approach 1:
The patent introduces an intermediary measurement system consisting of an aperture positioned at the beam focus point and an electron detector. This intermediary setup captures electrons directly from the focused beam through the aperture, providing sufficient signal intensity for vibration detection without requiring reflection from calibration marks, thus enabling vibration measurement in multi-beam operation mode.
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 configuration effectively measures and evaluates beam vibration, improving the accuracy of beam positioning and pattern writing in multi-beam writing apparatuses by enhancing the detection of beam currents and reducing noise, thereby increasing the throughput and precision of the writing process.
Implementation Method 1
a shaping aperture array plate including a plurality of first apertures through which a charged particle beam passes to form multiple beams
Implementation Method 2
a current detector detecting a current of the beam that has passed through the second aperture of the inspection aperture plate
Implementation Method 3
a deflector deflecting the multiple beams, the deflector controlling deflection of one of the multiple beams such that the one beam is located at a predetermined position
Data Source
AI summary
In one embodiment, a multi-charged-particle-beam writing apparatus includes a shaping aperture array plate including a plurality of first apertures through which a charged particle beam passes to form multiple beams, a movable stage on which a writing target substrate is placed, an inspection aperture plate disposed on the stage, the inspection aperture plate including a second aperture through which one of the multiple beams passes, a current detector detecting a current of the beam that has passed through the second aperture of the inspection aperture plate, a deflector deflecting the multiple beams, the deflector controlling deflection of one of the multiple beams such that the one beam is located at a predetermined position in a region including the second aperture and a surrounding region of the second aperture, and a calculator obtaining a beam position based on the beam current detected by the current detector.