Electron Optical Layout With Mirror Correction for Wafer Inspection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current inspection apparatuses for semiconductor wafers, such as optical and scanning electron microscopes, face challenges in balancing throughput and defect detection resolution, with optical inspectors struggling to detect fine defects over wide areas and SEMs having low throughput due to narrow fields of view and complex aberration correction requirements.
Innovation Solution
An electron beam application apparatus with a horizontal sample stage and an upright electron optical system incorporating a mirror aberration corrector, magnetic field sectors, and a doublet lens to correct aberrations and maintain electron beam alignment, allowing for high-resolution imaging while enabling efficient handling of semiconductor wafers in a manufacturing line setting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an electron optical system is arranged vertically with respect to a sample plane to enable semiconductor manufacturing line integration, then the adaptability to manufacturing lines is improved, but the throughput decreases due to pulsed electron beams required for linear optical path in aberration correction
Solution Approach 1:
The patent transitions from a vertical electron optical system (perpendicular to sample plane) to a horizontal arrangement (parallel to sample plane). This dimensional change allows the electron beams to travel horizontally through the aberration correction unit without requiring pulsed operation, thereby maintaining continuous beam flow and high throughput while still enabling semiconductor manufacturing line integration through the horizontal wafer stage configuration
Solution Approach 2:
The horizontal arrangement of the electron optical system enables continuous electron beam operation without pulsing. The electron beams continuously pass through the objective lens, magnetic field sectors, and mirror aberration corrector in a linear optical path, eliminating the interruptions inherent in pulsed beam systems and thereby maintaining high inspection throughput
2Measurement precision
If a mirror aberration corrector is used to correct electron beam aberrations, then the measurement precision of photoelectron images is improved, but the device complexity increases due to the need for advanced control techniques and pulsed electron beams
Solution Approach 1:
The patent extracts the complex control requirements for pulsed electron beams by changing the fundamental arrangement from vertical to horizontal. This allows the mirror aberration corrector to operate with continuous beams, separating the aberration correction function from the complex pulsed beam control system and thereby reducing overall device complexity while maintaining high measurement precision
Solution Approach 2:
The patent changes the operational parameter of the electron beam from pulsed to continuous by altering the optical path arrangement. This parameter change eliminates the need for advanced control techniques associated with pulsed beams, simplifying the aberration correction system while maintaining the ability to correct spherical and chromatic aberrations for high-resolution imaging
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 enhances the throughput and resolution of defect detection in semiconductor wafer inspection, providing a suitable solution for semiconductor manufacturing lines by optimizing electron beam alignment and aberration correction, thus improving the efficiency of photoelectron image acquisition.
Implementation Method 1
an objective lens for forming an electronic image by electrons emitted from the sample
Implementation Method 2
a plurality of magnetic field sectors by which an orbit of electrons passing through the objective lens is deviated from the optical axis
Implementation Method 3
a mirror aberration corrector... the orbit of the electrons emitted from the mirror aberration corrector is returned to the optical axis
Data Source
AI summary
Provided is a projection electron beam application apparatus suitable for use in semiconductor manufacturing lines. An electron optical system of the electron beam application apparatus includes a mirror aberration corrector 106 disposed perpendicular to an optical axis 109, a plurality of magnetic field sectors 104 by which an orbit of electrons is deviated from the optical axis to make the electrons incident on the mirror aberration corrector 106, and the orbit of the electrons emitted from the mirror aberration corrector 106 is returned to the optical axis, and a doublet lens 105 disposed between adjacent magnetic field sectors along the orbit of the electrons. The plurality of magnetic field sectors have the same deflection angle for deflecting the orbit of the electrons, and the doublet lens is disposed such that an object plane and an image plane thereof are respectively central planes of the adjacent magnetic field sectors along the orbit of the electrons.