Charged Particle Beam Device Dual Deflection Control
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Solution Overview
Problem
In semiconductor manufacturing, the deflection of electron beams leads to excessive deflection of secondary electrons, reducing their detection efficiency and image quality due to reduced signal-to-noise ratio in inspection images.
Innovation Solution
A charged particle beam device incorporating both electromagnetic and electrostatic deflection units, controlled by a unified control unit, to precisely manage the trajectory of both the electron beam and secondary electrons, ensuring they reach a reflection plate for optimal detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the electron beam is deflected by the deflector to scan the sample, then the inspection coverage is improved, but the secondary electrons are excessively deflected and may not arrive at the reflection plate, reducing detection efficiency
Solution Approach 1:
The patent applies dynamics by making the electron beam trajectory adjustable and controllable during scanning. The deflection unit is configured to dynamically adjust the electron beam trajectory based on scanning position information, ensuring that secondary electrons generated at different locations are properly directed to the reflection plate. This dynamic adjustment resolves the contradiction between maintaining wide inspection coverage and ensuring reliable secondary electron detection.
Solution Approach 2:
The patent implements feedback control where the control unit receives scanning position information and adjusts the deflection unit accordingly. The deflection unit modifies the electron beam trajectory based on feedback about the current scanning position, ensuring that secondary electrons are consistently directed toward the reflection plate regardless of the scanning location. This feedback mechanism maintains detection efficiency across the entire inspection area.
2Area of stationary object
If the electron beam is deflected to scan the sample, then the inspection area is increased, but the trajectory of secondary electrons is excessively deflected reducing the number of electrons reaching the reflection plate
Solution Approach 1:
The deflection unit dynamically adjusts the electron beam trajectory in real-time during scanning operations. As the electron beam scans across different areas of the sample, the deflection unit modifies the beam path to compensate for position-dependent deflection effects, ensuring that an adequate number of secondary electrons reach the reflection plate throughout the entire inspection area.
Solution Approach 2:
The patent changes the trajectory parameter of the electron beam based on scanning position. The control unit adjusts deflection parameters dynamically, modifying the beam trajectory to optimize secondary electron collection efficiency at different locations across the sample, thereby maintaining sufficient electron quantity reaching the reflection plate across the full inspection area.
3Adaptability or versatility
If the secondary electrons are excessively deflected, then the scanning flexibility is improved, but the detection efficiency is reduced and image quality deteriorates due to reduced signal-to-noise ratio
Solution Approach 1:
The control unit uses feedback from scanning position information to adjust the deflection unit, maintaining optimal electron beam trajectories throughout the scanning process. This feedback control ensures that while scanning flexibility is maintained across different areas, the secondary electron trajectories are consistently optimized for detection, preserving high detection efficiency and image quality with adequate signal-to-noise ratio.
Solution Approach 2:
The patent dynamically changes deflection parameters based on scanning position to maintain optimal detection conditions. By adjusting trajectory parameters in real-time, the system preserves scanning flexibility while preventing excessive deflection of secondary electrons, thereby maintaining high measurement precision and image quality throughout the inspection process.
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 enhances the detection efficiency of secondary electrons, improving the signal-to-noise ratio and image quality by dynamically controlling the electron beam and secondary electron trajectories, preventing their loss and ensuring accurate inspection images.
Implementation Method 1
an electromagnetic deflection unit that electromagnetically performs scanning with the charged particle beam by a magnetic field
Implementation Method 2
an electrostatic deflection unit that electrostatically performs scanning with the charged particle beam by an electric field
Implementation Method 3
a reflection plate that reflects secondary electrons generated from the sample
Data Source
AI summary
A charged particle beam device includes a deflection unit that deflects a charged particle beam released from a charged particle source to irradiate a sample, a reflection plate that reflects secondary electrons generated from the sample, and a control unit that controls the deflection unit based on an image generated by detecting the secondary electrons reflected from the reflection plate. The deflection unit includes an electromagnetic deflection unit that electromagnetically scans with the charged particle beam by a magnetic field and an electrostatic deflection unit that electrostatically scans with the charged particle beam by an electric field. The control unit controls the electromagnetic deflection unit and the electrostatic deflection unit, superimposes an electromagnetic deflection vector generated by the electromagnetic scanning and an electrostatic deflection vector generated by the electrostatic scanning, and controls at least a trajectory of the charged particle beam.