Charged Particle Beam Device Low-Voltage Pulsed Scanning
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Solution Overview
Problem
Current charged particle beam devices face challenges in non-destructive observation of internal sample structures, as high acceleration voltages damage the sample, and materials with high permittivity and insulation lead to low contrast due to electrostatic charging, while existing methods to suppress charging result in insufficient contrast for materials with small electric characteristic differences.
Innovation Solution
A charged particle beam device that includes a charged particle beam source, a sample table, a charged particle beam optical system for pulsating and accelerating the beam within 0 kV to 5 kV, a split distance selector, and a controller to control the beam's irradiation based on selected measurement objectives, allowing for low-damage observation of both surface and internal structures by adjusting the split distance between irradiation regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high acceleration voltage is applied to observe internal structure, then penetration depth increases and internal structure becomes visible, but sample damage increases
Solution Approach 1:
The patent applies periodic action by using pulsed electron beam irradiation instead of continuous irradiation. The electron beam is irradiated in pulses with specific timing, allowing the sample to recover between pulses and reducing cumulative damage while still achieving sufficient penetration depth for internal structure observation
Solution Approach 2:
The patent changes the parameter of acceleration voltage to operate within a specific range (1 kV to 5 kV) that balances penetration depth and sample damage. This parameter optimization allows internal structure observation without requiring excessively high voltages that would cause severe sample damage
2Object-affected harmful factors
If pulse electron beam with synchronous control is used to suppress electrostatic charging, then charging influence is reduced, but contrast is insufficient for materials with small electric characteristic differences
Solution Approach 1:
The patent optimizes multiple parameters including acceleration voltage (1-5 kV), pulse width (1 µs to 100 ms), and duty ratio (1% to 50%) to achieve a balance between suppressing electrostatic charging and maintaining sufficient image contrast for materials with small electric characteristic differences
3Length of stationary object
If acceleration voltage is raised for internal structure observation, then electron beam penetration increases, but sample damage occurs
Solution Approach 1:
The patent uses periodic pulsed irradiation to achieve sufficient penetration depth through accumulated effect over multiple pulses while allowing sample recovery between pulses, avoiding the need for continuously high voltage that would cause damage
Solution Approach 2:
The patent changes the acceleration voltage to an optimized range (1-5 kV) that provides adequate penetration depth for internal structure observation without causing excessive sample damage
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 discriminable visualization of surface shapes, internal structures, and electric characteristics with reduced sample damage and enhanced contrast, using low acceleration voltages to control electrostatic charging and optimize image acquisition.
Implementation Method 1
a charged particle beam optical system that accelerates and pulsates a charged particle beam emitted from the charged particle beam source, and irradiates the charged particle beam to the sample at an acceleration voltage within a range of 0 kV to 5 kV
Implementation Method 2
The depth of entrance of the electron beam in the sample depends on the energy of the electron beam
Implementation Method 3
Reflection electrons are emitted from the internal structure in the depth position where the electron beam entered
Implementation Method 4
a method of controlling electron irradiation amount and an irradiation waiting period with a pulse electron beam, so as to realize observation of a structure hidden with potential contrast due to electrostatic charging caused by charging and discharging to/from the sample
Implementation Method 5
a method of suppressing electrostatic charging with a pulse electron beam, Patent Literature 2 discloses a method for controlling a split distance between irradiated pixels by synchronous control between a pulse electron beam and scanning
Data Source
AI summary
To provide a charged particle beam device which enables observation and evaluation of the surface and the inside of a sample with low damage to the sample, the charged particle beam device has: a charged particle beam source 2; a sample table 9 in which the sample 210 is placed; a charged particle beam optical system which pulsates a charged particle beam 100 and irradiates the charged particle beam to the sample at an acceleration voltage within a range of 0 kV to 5 kV; a split distance selector 125 for selecting a measurement object of the sample; and a split distance setting unit 124 for setting a split distance in one line scanning of the charged particle beam on the sample.