Plasma Guide Electrode Layout for SEM Charge Neutralization
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Solution Overview
Problem
Existing charged particle beam devices face challenges in effectively removing static charge from samples without interfering with the control of the charged particle beam, particularly in scanning electron microscopes used for semiconductor inspection, which affects measurement accuracy and throughput.
Innovation Solution
A charged particle beam device with a plasma generation device and a guide that directs plasma or charged particles to the sample while maintaining the same potential as the stage, avoiding interference with the electron beam optical system, using voltage sources to control the plasma and guide potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma or ions are caused to propagate to the vicinity of a sample using an introduction tube, then charge removal is achieved, but the magnetic field or electric field that controls the electron beam is affected
Solution Approach 1:
A guide electrode is introduced as an intermediary component between the plasma source and the sample. The guide electrode has a hollow portion that directs plasma/ions toward the sample while its potential is controlled to prevent interference with the electron beam's magnetic and electric fields, thus mediating between charge removal needs and beam control precision
Solution Approach 2:
The guide electrode is maintained at the same potential as the sample stage through a voltage source. This equipotential configuration ensures that the guide electrode does not create additional electric field disturbances that would affect electron beam control, while still allowing plasma/ions to reach the sample for charge removal
2Productivity
If low magnification imaging with high current is used to inspect wide range, then throughput is improved, but charging of sample causes distortion and brightness unevenness
Solution Approach 1:
Plasma or ions are irradiated to the sample before electron beam imaging to preemptively remove or control charges on the sample surface. This preliminary charge removal action prevents charging effects during subsequent high-current low-magnification imaging, enabling both high throughput and good image quality
Solution Approach 2:
The plasma/ion irradiation converts the harmful charging effect into a beneficial pre-treatment. By intentionally introducing plasma/ions to neutralize charges before imaging, the harmful charging distortion is transformed into a useful charge control mechanism that enables high-current imaging without quality degradation
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
Achieves static elimination and charge control without influencing the charged particle beam control, enhancing measurement accuracy and throughput by preventing charge-related distortions and dielectric breakdown.
Implementation Method 1
a plasma generation device configured to generate a plasma or charged particles; a guide including a hollow portion configured to guide the plasma generated by the plasma generation device in a direction toward the stage
Implementation Method 2
a second voltage source configured to adjust the plasma generation device and the guide to a predetermined potential
Implementation Method 3
the charged particle beam optical system includes an objective lens configured to focus the charged particle beam on the sample
Data Source
AI summary
A charged particle beam device includes: a plasma generation device attached to a sample chamber through a connecting member; a guide including a hollow portion configured to guide a plasma generated by the plasma generation device in a direction toward a stage; a first voltage source configured to apply a voltage to the stage; and a second voltage source configured to adjust the plasma generation device and the guide to a predetermined potential, in which the guide is disposed to avoid an opening of an objective lens through which a charged particle beam passes and to position a tip of the guide between the objective lens and the stage.