Multi-electron-beam Imaging Apparatus with Reduced Column Length
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Solution Overview
Problem
Multi-electron beam imaging systems face challenges in achieving desirable image quality due to Coulomb interactions, which lead to beam spreading and reduced image intensity, limiting throughput and resolution.
Innovation Solution
A multi-electron beam imaging apparatus with a reduced electron beam column length of less than 300 mm is designed to minimize Coulomb interactions, featuring a single individual beam crossover plane and a single common beam crossover plane, along with a corrector lens and objective lens configuration to reduce aberrations and enhance image resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-electron beam imaging is used to increase throughput, then productivity is improved, but image quality deteriorates due to Coulomb interactions and beam spreading
Solution Approach 1:
The system divides a single electron beam into multiple parallel electron beams using an aperture plate with multiple apertures. This segmentation allows simultaneous imaging of multiple areas of the sample, increasing throughput while maintaining image quality by keeping beam currents in each individual beam at optimal levels, thereby avoiding Coulomb interaction effects that would occur in a single high-current beam
Solution Approach 2:
The invention transitions from a single-beam sequential imaging approach to a multi-beam parallel imaging approach by adding the spatial dimension of multiple beams. The aperture plate creates an array of beams that can simultaneously interrogate different regions of the sample, effectively utilizing spatial parallelism to improve productivity without sacrificing image quality
2Illumination intensity
If electron beam current is increased to improve image intensity, then image quality is improved, but beam spreading increases due to Coulomb interactions
Solution Approach 1:
The total electron current is segmented into multiple parallel beams, each carrying a fraction of the total current. This allows the system to achieve high overall image intensity through multiple beams while each individual beam maintains low enough current to avoid significant Coulomb interactions and beam spreading
Solution Approach 2:
The system merges multiple low-current beams into a high-intensity imaging system by simultaneously illuminating multiple areas of the sample. The combined effect of multiple beams provides high overall image intensity while each beam operates at low current to minimize beam spreading
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
The solution effectively reduces beam spreading and maintains high beam currents, improving image quality and throughput without compromising resolution, as evidenced by the quadratic scaling of electron-electron interactions with column length.
Implementation Method 1
an electron source for producing a precursor electron beam
Implementation Method 2
an aperture plate comprising an array of apertures for producing an array of electron beams from said precursor electron beam
Implementation Method 3
The reduced column length, for example, reduces Coulomb interactions and allows for improved imaging at higher electron beam currents
Implementation Method 4
an electron beam column, for directing said array of electron beams onto said specimen
Data Source
AI summary
A multi-electron beam imaging apparatus is disclosed herein. An example apparatus at least includes an electron source for producing a precursor electron beam, an aperture plate comprising an array of apertures for producing an array of electron beams from said precursor electron beam, an electron beam column for directing said array of electron beams onto a specimen, where the electron beam column is configured to have a length less than 300 mm, and where the electron beam column comprises a single individual beam crossover plane in which each of said electron beams forms an intermediate image of said electron source, and a single common beam crossover plane in which the electron beams in the array cross each other.