Charged-Particle Beam Focusing for Stage Motion Compensation
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Solution Overview
Problem
Existing charged-particle beam inspection systems face limitations in high precision stage motion control, leading to challenges in imaging resolution and throughput, particularly in the inspection of integrated circuits with shrinking feature sizes and complex architectures.
Innovation Solution
A charged-particle beam system with a movable stage and position sensing system, utilizing controllers to apply signals for beam deflection and focus adjustment, and independently controlled motors for precise stage leveling, along with dynamic signal adjustments to compensate for lateral and vertical displacements and angular rotations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional stage motion control mechanisms are used, then device complexity is reduced, but manufacturing precision deteriorates
Solution Approach 1:
The patent implements feedback control by using position sensing systems to detect stage displacement and feeding this information back to controllers that adjust beam deflection and focus signals accordingly. This closed-loop feedback mechanism enables high precision stage motion control by continuously compensating for deviations from target positions.
Solution Approach 2:
The patent replaces mechanical stage motion control with electromagnetic beam deflection and focus adjustment. Instead of relying solely on mechanical precision, the system uses electromagnetic fields to compensate for stage positioning errors, substituting mechanical control with field-based control to achieve higher precision.
2Measurement precision
If high precision stage motion control is implemented, then imaging resolution is improved, but device complexity increases
Solution Approach 1:
The patent introduces electromagnetic fields as intermediaries between the stage positioning system and the imaging system. The beam deflection and focus adjustment signals act as intermediaries that translate stage position information into corrected beam trajectories, enabling high imaging resolution without requiring the entire system to operate at peak precision simultaneously.
Solution Approach 2:
The patent dynamically changes electromagnetic field parameters (beam deflection angles, focus distances) based on detected stage position deviations. By adjusting these parameters in real-time according to actual stage position feedback, the system maintains high imaging resolution despite variations in mechanical positioning.
3Reliability
If real-time vibration compensation is applied, then reliability is improved, but use of energy increases
Solution Approach 1:
The patent applies periodic dynamic signal adjustments to compensate for vibrations. The controllers apply correction signals at frequencies matching the vibration characteristics of the stage and beam system, using periodic modulation of beam deflection and focus to counteract repetitive vibrational disturbances and maintain image stability.
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
Enhances imaging resolution and throughput by achieving high precision stage motion control, enabling real-time 3D imaging and accurate defect detection in integrated circuits with complex architectures.
Implementation Method 1
a controller configured to apply a first signal to deflect a primary charged-particle beam incident on the sample to at least partly compensate for the lateral displacement of the stage
Implementation Method 2
apply a second signal to adjust a focus of a deflected charged-particle beam incident on the sample to at least partly compensate for the vertical displacement of the stage
Implementation Method 3
a position sensing system to determine a lateral and vertical displacement of the stage
Implementation Method 4
Each of the plurality of motors may comprise at least one of a piezoelectric motor, piezoelectric actuator, or an ultrasonic piezo-motor
Data Source
AI summary
Systems and methods for irradiating a sample with a charged-particle beam are disclosed. The charged-particle beam system may comprise a stage configured to hold a sample and is movable in at least one of X-Y-Z axes. The charged-particle beam system may further comprise a position sensing system to determine a lateral and vertical displacement of the stage, and a beam deflection controller configured to apply a first signal to deflect a primary charged-particle beam incident on the sample to at least partly compensate for the lateral displacement, and to apply a second signal to adjust a focus of the deflected charged-particle beam incident on the sample to at least partly compensate for the vertical displacement of the stage. The first and second signals may comprise an electrical signal having a high bandwidth in a range of 10 kHz to 50 kHz, and 50 kHz to 200 kHz, respectively.