Charged Particle Beam Device Control Electrode Lens Distortion
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Solution Overview
Problem
The resolution of charged particle beam devices deteriorates due to distortion of the electric field lens caused by sample irregularities or inclination, leading to degraded performance.
Innovation Solution
A charged particle beam device incorporating a boosting electrode, a control electrode, and pole pieces with lens coils to form and control electric and magnetic fields, preventing distortion of the electric field lens and maintaining high resolution observation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a boosting type magnetic field lens with superimposed electric field lens is used, then high resolution in low energy observation is achieved, but the electric field lens becomes distorted when sample surface has irregularities or sample is inclined, degrading lens performance
Solution Approach 1:
The objective lens is divided into separate magnetic field lens and electric field lens components. The magnetic field lens (first lens) and electric field lens (second lens) are independently controllable, allowing the magnetic field lens to maintain focusing function while the electric field lens provides energy modulation without distortion affecting both simultaneously.
Solution Approach 2:
A control electrode is introduced as an intermediary component between the boosting electrode and the sample. This control electrode generates a control electric field that counteracts the distortion caused by sample irregularities or inclination, thereby stabilizing the electric field lens performance and preventing degradation of overall lens function.
2Measurement precision
If electric field lens is formed on the sample, then high resolution observation is enabled, but distortion occurs due to sample irregularities or inclination
Solution Approach 1:
The control electrode applies a preliminary counteracting electric field before the distorted electric field lens acts on the charged particle beam. By anticipating and compensating for the distortion caused by sample irregularities or inclination, the control electrode prevents the electric field lens from becoming distorted in the first place.
Solution Approach 2:
The voltage applied to the control electrode is dynamically adjusted based on the sample conditions (irregularities or inclination). By changing the electric field parameters (voltage, field strength) in response to sample variations, the system maintains a stable electric field lens shape and prevents distortion.
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 high resolution observation by preventing distortion of the electric field lens, improving lens performance regardless of sample form or inclination, and allowing for both high resolution and electromagnetic field-free observation.
Implementation Method 1
a boosting electrode disposed between the charged particle source and a sample to form a path of the charged particle beam and to accelerate and decelerate the charged particle beam
Implementation Method 2
a first lens coil disposed outside the first pole piece and inside the second pole piece to form a first lens; a second lens coil disposed outside the second pole piece to form a second lens
Implementation Method 3
a control electrode formed between a distal end portion of the first pole piece and a distal end portion of the second pole piece to control an electric field formed between the sample and the distal end portion of the second pole piece
Data Source
AI summary
A charged particle beam device includes: a charged particle source that emits a charged particle beam; a boosting electrode disposed between the charged particle source and a sample to form a path of the charged particle beam and to accelerate and decelerate the charged particle beam; a first pole piece that covers the boosting electrode; a second pole piece that covers the first pole piece; a first lens coil disposed outside the first pole piece and inside the second pole piece to form a first lens; a second lens coil disposed outside the second pole piece to form a second lens; and a control electrode formed between a distal end portion of the first pole piece and a distal end portion of the second pole piece to control an electric field formed between the sample and the distal end portion of the second pole piece.