Cathode Gap Area Ratio Selection for Electron Beam Brightness
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Solution Overview
Problem
The challenge in achieving high brightness for electron beam writing apparatuses lies in the difficulty of accurately determining the optimal gap distance between the cathode and carbon coating, as large gaps result in reduced brightness and variability in cathode production, making it hard to ensure apparatus reliability.
Innovation Solution
A method involving the production of cathodes with a gap between the electron emission member and the carbon cover part, where the area ratio of the gap to the upper surface is measured and correlated with desired brightness levels to select cathodes that meet specific brightness requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gap is provided between the cathode material and the carbon coating to inhibit chemical reaction, then the reliability of the cathode is improved, but the brightness is deteriorated when the gap is large
Solution Approach 1:
The patent changes the geometric parameters of the cathode structure, specifically the cone angle and dimensions of the electron emission member, to optimize the gap area ratio. By controlling parameters like the upper diameter, lower diameter, and height of the conical emission member, the patent achieves an optimal balance between gap size (for reliability) and brightness performance.
2Stability of the object's composition
If the gap distance is increased to prevent chemical interaction, then the stability of the cathode structure is improved, but the manufacturing precision becomes difficult to control due to variability in products
Solution Approach 1:
The patent introduces a feedback mechanism by calculating the gap area ratio based on measurable dimensions (upper diameter, lower diameter, height) and comparing it against predetermined optimal ranges. This allows for quality control and selection of cathodes that meet brightness requirements, compensating for variations in the manufacturing process.
Solution Approach 2:
The patent performs preliminary calculation and selection of cathodes based on their geometric parameters before actual use. By pre-determining the optimal gap area ratio range and selecting cathodes within this range, the patent ensures consistent brightness performance without requiring post-manufacturing adjustment.
3Duration of action of stationary object
If the gap is made large to prevent chemical reaction between carbon coating and cathode material, then the durability of the cathode is improved, but the brightness required for electron beam writing apparatus is not achieved
Solution Approach 1:
The patent optimizes the geometric parameters of the electron emission member (cone angle, upper diameter, lower diameter, height) to achieve an optimal gap area ratio. This controlled parameter adjustment ensures sufficient gap size for durability while maintaining adequate brightness for electron beam writing applications.
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 allows for the selection of cathodes that achieve the desired brightness, enhancing the reliability and performance of electron beam writing apparatuses by ensuring consistent high-brightness emission.
Implementation Method 1
an electron emission member (30) and a cover part (40), provided with a gap (50), wherein the cover part (40) covers a side surface (21) of the electron emission member (30)
Data Source
AI summary
A cathode obtaining method includes producing a plurality of cathodes each including an electron emission member and a cover part, provided with a gap, which covers a side surface of the electron emission member, measuring an outer dimension of the upper surface of the electron emission member, for each of a plurality of cathodes, measuring an outer dimension of the gap at the same surface as the upper surface of the electron emission member, for each of a plurality of cathodes, calculating an area ratio by dividing the area of the gap, for each of a plurality of cathodes, obtaining an upper limit of the area ratio corresponding to a desired brightness by using a correlation between brightness and the area ratio, and selecting a cathode having the area ratio less than or equal to the upper limit from a plurality of cathodes that have been produced.