Blanking Aperture Array Device Electrostatic Charge Suppression
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Solution Overview
Problem
Existing blanking aperture array devices for multi-beams face challenges in inhibiting electrostatic charge during beam irradiation due to exposed insulating films, leading to beam distortion and blur, and current antistatic measures complicate the fabrication process.
Innovation Solution
A method involving a substrate with a laminated structure of insulating and metal films, where electrodes and pads are formed on the surface, and the region between them is covered with a metal film to prevent exposure of insulating films, ensuring that only metal surfaces are exposed to the beams, thus inhibiting electrostatic charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulating films are exposed on the surface of the blanking aperture array device, then the fabrication process is simpler, but electrostatic charge occurs during beam irradiation causing beam distortion and blur
Solution Approach 1:
The harmful insulating film is selectively removed from the surface through etching processes, extracting only the necessary protective layer while eliminating the source of electrostatic charge. This allows the metal electrode structure to be exposed, preventing charge accumulation during beam irradiation while maintaining fabrication feasibility through controlled material removal.
Solution Approach 2:
The surface composition parameter is changed from insulating material to conductive metal material. By controlling the etching depth and selecting appropriate metal films, the surface electrical conductivity is transformed, enabling charge dissipation during beam operation while preserving the underlying electrode functionality.
2Reliability
If metal films are applied over insulating films to prevent electrostatic charge, then beam distortion is prevented, but the fabrication process becomes more complex
Solution Approach 1:
The electrode structure and charge-prevention function are merged into a single integrated component. The metal film that forms the electrode also serves as the charge-dissipating surface, eliminating the need for separate antistatic layers and simplifying the overall fabrication process while maintaining beam stability.
Solution Approach 2:
The metal film performs multiple functions simultaneously: it acts as the electrode for beam deflection control and as the conductive surface for preventing electrostatic charge accumulation. This multi-functionality reduces the number of fabrication steps while achieving both beam control and charge prevention.
3Reliability
If electrodes are formed on the side wall of passage holes or by bonding separate substrates, then electrostatic charge is inhibited, but the fabrication process becomes complicated
Solution Approach 1:
The electrode structure is segmented into planar regions that extend toward and connect at the passage hole boundaries. This segmentation allows charge inhibition at critical locations while maintaining a simple planar fabrication process, avoiding the need for complex side-wall formation or substrate bonding techniques.
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 suppresses electrostatic charge during multi-beam irradiation, simplifying the fabrication process and preventing beam distortion, while ensuring that only metal surfaces are exposed to the beams.
Implementation Method 1
If a protection insulating film is exposed on the surface of a fabricated blanking aperture array device, the exposed insulator on the surface is charged (electrified) due to irradiation of beams emitted by the writing apparatus incorporating the blanking aperture array device. Therefore, there is a problem that beam distortion or blur occurs because of the electrostatic charge.
Data Source
AI summary
A method for fabricating a blanking aperture array device for multi-beams includes forming, using a substrate over which a first insulating film, a first metal film, a second insulating film, and a second metal film are laminated in order, electrodes and pads on the second metal film, removing a part of the second metal film, removing the second insulating film using, as a mask, the electrodes, the pads, and a remaining part of the second metal film, and forming openings each being between a pair of electrodes, wherein, a part of the second metal film is etched such that some part of it remains in regions each connecting one of the electrodes and one of the pads, and a region in which entire openings are formed except the openings themselves is configured by the electrodes, pads, and first and second metal films such that the insulating film is not exposed.