Charged-Particle Beam Deflector Aberration Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing charged-particle beam systems face challenges in simultaneously correcting deflection comatic and chromatic aberrations while determining the beam incidence position without increasing deflection voltage or reducing the electrode diameter, as existing methods either require excessive deflection voltage or cannot completely correct aberrations.
Innovation Solution
A charged-particle beam system with three interlocking deflectors, where the first deflector is placed before the demagnifying lens, the second deflector's field is partially overlapped with the objective lens field, and the third deflector is placed after the second, with equal deflection signals applied to the second and third deflectors, and intensity distributions adjusted to cancel out aberrations, allowing for simultaneous correction of comatic and chromatic aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If three interlocking deflectors are used to correct deflection comatic and chromatic aberrations simultaneously, then lithography accuracy is improved, but deflection voltage increases excessively
Solution Approach 1:
The patent changes the spatial arrangement parameter of the deflectors by placing the second deflector within the objective lens field where its deflection field overlaps with the lens field. This parameter change allows the system to achieve aberration correction with lower deflection voltage while maintaining three degrees of freedom for simultaneous correction of comatic and chromatic aberrations.
2Measurement precision
If the deflector is located close to the object point with small electrode length, then deflection sensitivity is improved, but deflection aberration correction capability deteriorates
Solution Approach 1:
The patent adds a spatial dimension consideration by placing the second deflector within the objective lens field, creating an overlapping region between deflection field and lens field. This dimensional arrangement allows the system to achieve both high deflection sensitivity (through close positioning) and aberration correction capability (through field overlap), resolving the contradiction between these two requirements.
3Use of energy by moving object
If electrode inside diameter is reduced to lower deflection voltage, then deflection voltage is reduced, but contaminant adhesion and charging problems increase
Solution Approach 1:
The patent changes the spatial arrangement parameter by positioning the second deflector within the objective lens field with overlapping fields, rather than simply reducing electrode diameter. This parameter change allows the system to achieve lower deflection voltage operation while maintaining adequate electrode dimensions, thereby avoiding contaminant adhesion and charging problems.
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 enables simultaneous correction of deflection comatic and chromatic aberrations at the objective lens image plane without increasing the electrode length or reducing the electrode diameter, maintaining low deflection voltage, thus enhancing lithography accuracy to nanometer levels.
Implementation Method 1
a charged-particle beam source for producing a charged-particle beam
Implementation Method 2
a demagnifying lens for demagnifying dimensions of the charged-particle beam produced from the charged-particle beam source
Implementation Method 3
an objective lens for focusing the charged-particle beam whose dimensions have been demagnified by the demagnifying lens onto a surface of a target
Implementation Method 4
a first deflector disposed in a stage preceding the demagnifying lens or close to the object plane of the objective lens
Implementation Method 5
a second deflector disposed such that a deflection field produced by the second deflector itself is totally or partially overlapped on the field produced by the objective lens
Data Source
AI summary
A charged-particle beam system has a demagnifying lens for reducing the dimensions of an electron beam produced from an electron beam source, an objective lens for focusing the demagnified beam onto the surface of a target, a first deflector located before the demagnifying lens, a second deflector placed such that the deflection field produced by it is totally or partially superimposed on the objective lens field, and a third deflector located in a stage following the second deflector. An image of the light source is created by the demagnifying lens. An image of the light source image is formed on the target by the objective lens.