SEM Dual-Focus Positioning for Multi-Energy Metrology
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electron beam inspection apparatuses face challenges in efficiently switching between high and low landing energy operational modes due to significant focus position differences, leading to extended downtime for stabilization and limited capability to position substrates within the focus range of both modes.
Innovation Solution
Incorporating a combination of fine and coarse z-positioning devices, along with a controller for switching operational modes, allows the apparatus to adjust the substrate's position along the optical axis, enabling focus adaptation for varying landing energies and reducing idle times by compensating for focus position differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single electron beam inspection apparatus is used to operate across both high and low landing energy modes, then the apparatus can handle multiple inspection requirements, but the significant focus position difference between modes causes extended stabilization time and positioning limitations
Solution Approach 1:
The positioning system is divided into two independent devices: a first positioning device for coarse adjustment over a large range, and a second positioning device for fine adjustment over a small range. This segmentation allows each device to be optimized for its specific function, enabling rapid mode switching while maintaining positioning precision across both high and low landing energy modes.
Solution Approach 2:
The controller automatically adjusts the positioning devices in advance when switching between operational modes. The first positioning device performs preliminary coarse positioning to bring the substrate within the focus range, followed by the second positioning device for precise focus adjustment. This preliminary action eliminates manual intervention and reduces stabilization time during mode transitions.
2Adaptability or versatility
If only a single positioning device with limited range is used, then the device complexity is reduced, but the substrate cannot be positioned within the focus range of both high and low landing energy modes
Solution Approach 1:
The positioning system is divided into two independent devices: a first positioning device for coarse adjustment over a large range, and a second positioning device for fine adjustment over a small range. This segmentation allows each device to be optimized for its specific function, enabling rapid mode switching while maintaining positioning precision across both high and low landing energy modes.
Solution Approach 2:
The first and second positioning devices are arranged such that they operate in a nested manner along the optical axis. The first positioning device provides the primary positioning framework, while the second positioning device operates within the range established by the first device. This nested arrangement maximizes the effective positioning range while maintaining system compactness.
3Measurement precision
If the focus position is adjusted manually when switching between high and low landing energy modes, then the positioning can be accurate, but the process time increases and automation is reduced
Solution Approach 1:
The controller automatically adjusts the positioning devices in advance when switching between operational modes. The first positioning device performs preliminary coarse positioning to bring the substrate within the focus range, followed by the second positioning device for precise focus adjustment. This preliminary action eliminates manual intervention and reduces stabilization time during mode transitions.
Solution Approach 2:
The controller receives signals indicating the current operational mode and automatically calculates the required focus position adjustments. The controller then actuates the positioning devices to achieve the correct focus position for the selected mode, creating a closed-loop feedback system that maintains positioning accuracy while enabling rapid mode switching.
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
Enables efficient operation of a single electron beam inspection apparatus across a wide range of landing energies without prolonged stabilization times, ensuring accurate positioning and image acquisition in both high and low landing energy modes.
Implementation Method 1
a particle beam generator configured for generating a particle beam to be irradiated onto a substrate
Implementation Method 2
optics configured for focusing the particle beam
Data Source
AI summary
There is provided a charged particle apparatus comprising: a particle beam generator, optics, a first and a second positioning device, both configured for positioning the substrate relative to the particle beam generator along its optical axis, and a controller configured for switching between a first operational mode and a second operational mode. The apparatus is configured, when operating in the first operational mode, for irradiating the substrate by the particle beam at a first landing energy of the particle beam and, when operating in the second operational mode, for irradiating the substrate at a second, different landing energy. When operating in the first operational mode, the second positioning device is configured to position the substrate relative to the particle beam generator at a first focus position of the particle beam and in the second operational mode, to position the substrate at a second, different focus position.