Segmented Beam Deflectors With HV Switching for Faster Electron Scanning
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Solution Overview
Problem
Existing charged particle beam inspection systems face limitations in achieving high throughput while maintaining image quality, particularly in scanning electron microscopes, due to constraints in electron beam deflection and driver circuit design, especially when dealing with high landing energy beams for sub-surface defect detection.
Innovation Solution
A scanning deflection system utilizing high speed and high voltage switches to manipulate electron beams, replacing conventional components like linear amplifiers and DACs, and employing segmented deflectors with dedicated driver systems for precise beam control, enabling faster and more accurate scanning with reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional high voltage linear amplifiers are used for electron beam deflection, then the system is simpler to implement, but the beam manipulation speed is slower and power consumption is higher
Solution Approach 1:
The patent replaces conventional high voltage linear amplifiers with high voltage switches and opposing electrode configurations. This substitution transforms the continuous analog control system into a discrete digital control system using CMOS switches, achieving faster beam manipulation speed while reducing power consumption despite increased circuit complexity
Solution Approach 2:
The deflection system is divided into multiple layers with opposing electrodes (first set and second set of opposing electrodes in each layer). This segmentation allows independent control of each electrode pair, enabling faster voltage transitions and improved beam deflection speed through parallel operation of multiple switch pairs
2Productivity
If the field-of-view is increased for larger inspection areas, then the throughput improves, but the image quality may deteriorate
Solution Approach 1:
The patent implements dynamic voltage control of the deflection electrodes through high voltage switches that can rapidly change voltage states. This dynamic control allows the system to maintain precise beam positioning and focus across larger field-of-view areas, enabling both increased throughput and preserved image quality through real-time adjustment of deflection parameters
3Productivity
If multiple electron beams are used to increase throughput, then the inspection speed improves, but the deflection system complexity increases
Solution Approach 1:
The multi-layer opposing electrode structure with high voltage switch control serves multiple functions: it can deflect multiple electron beams simultaneously, control beam positioning across large field-of-view areas, and maintain precise focusing. This universal deflection system handles both single-beam and multi-beam operations without requiring separate deflection circuits for each beam, managing complexity while enabling high throughput
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
The system achieves faster beam manipulation, improved image quality, and reduced power consumption, enhancing the reliability and throughput of charged particle beam inspection systems, particularly for inspecting complex IC structures with high landing energy beams.
Implementation Method 1
A plurality of electrodes having a first set of opposing electrodes and a second set of opposing electrodes... configured to provide a plurality of discrete output states to the first set of opposing electrodes... to influence an electron beam
Implementation Method 2
replacing conventional high voltage linear amplifiers with high voltage switches for faster and more accurate beam manipulation
Data Source
AI summary
An apparatus includes a first charged particle beam manipulator positioned in a first layer configured to influence a charged particle beam and a second charged particle beam manipulator positioned in a second layer configured to influence the charged particle beam. The first and second charged particle beam manipulators may each include a plurality of electrodes having a first set of opposing electrodes and a second set of opposing electrodes. A first driver system electrically connected to the first set may be configured to provide a plurality of discrete output states to the first set. A second driver system electrically connected to the second set may be configured to provide a plurality of discrete output states to the second set. The first and second charged-particle beam manipulators may each comprise a plurality of segments; and a controller having circuitry configured to individually control operation of each of the plurality of segments.