Electron Beam Apparatus for Surface Charge Control and Inspection
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Solution Overview
Problem
Existing electron beam apparatuses face challenges in achieving both precise surface charge control and high throughput due to limitations in the separation of electron beams for inspection and surface charge control, leading to inefficiencies in defect detection and measurement precision.
Innovation Solution
The apparatus separates electron beams generated from a single source into at least two, using one for surface charge control and another for generating secondary charged particles, allowing distinct detection of these particles to improve surface charge control and inspection throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a preliminary electron source is used for surface charge control, then surface charge control is achieved, but the space between irradiation positions cannot be made small and time lag increases
Solution Approach 1:
The electron beam is divided into two separate beams: one for surface charge control and another for signal acquisition. This segmentation allows each beam to be optimized for its specific function while eliminating the time lag issue by using the same electron optical column for both purposes sequentially.
Solution Approach 2:
The same electron optical column is used for both surface charge control and signal acquisition functions. By making the electron optical column universal, the patent eliminates the need for a separate preliminary electron source, thereby reducing the time lag while maintaining effective surface charge control.
2Device complexity
If the primary electron beam is used for both surface charge control and signal acquisition, then device complexity is reduced, but inspection efficiency decreases due to double irradiation of the same area
Solution Approach 1:
The single primary electron beam is segmented into two separate beams: one dedicated to surface charge control and another to signal acquisition. This allows simultaneous optimization of both functions without the inefficiency of double irradiation, maintaining simple device architecture while improving inspection efficiency.
Solution Approach 2:
The patent dynamically controls the electron beam by selectively applying it to different areas: surface charge control beam irradiates areas needing charge neutralization, while the signal acquisition beam irradiates areas requiring inspection. This dynamic allocation improves inspection efficiency while maintaining device simplicity.
3Reliability
If electron beams are separated for surface charge control and signal acquisition, then both functions can be optimized, but device complexity increases
Solution Approach 1:
The electron beam is segmented into two functional beams that share the same electron optical column. This segmentation enables optimized control for each function while avoiding the complexity of duplicating the entire electron optical system, as both beams utilize the same column infrastructure.
4Productivity
If a multicolumn method is used to increase detection area, then throughput is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent employs dynamic beam control within a single electron optical column, allowing the same column to serve multiple functions (surface charge control and signal acquisition) at different times and locations. This dynamic utilization achieves high throughput without the complexity and cost of multiple columns.
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 enables both precise surface charge control and high inspection throughput by allowing for the effective separation and detection of secondary charged particles, enhancing the precision and efficiency of defect detection and measurement.
Implementation Method 1
an electron source for generating an electron beam
Implementation Method 2
irradiates the other as an electron beam for generation of the secondary charged particle (the secondary electron and the back scattering electron) on the sample
Data Source
AI summary
A plurality of primary beams are formed from a single electron source, the surface charge of a sample is controlled by at least one primary beam, and at the same time, the inspection of the sample is conducted using a primary beam other than this. Also, for an exposure area of the primary beam for surface charge control and an exposure area of the primary beam for the inspection, the surface electric field strength is set individually. Also, the current of the primary beam for surface charge control and the interval between the primary beam for surface charge control and the primary beam for inspection are controlled.