Adjustable Aperture for Charged-Particle Beam Signal Discrimination
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Solution Overview
Problem
Existing scanning electron microscopes face challenges in optimizing the visibility of hole and groove bottoms in semiconductor devices due to fixed opening sizes and difficulties in maintaining adjustable mechanisms within limited vacuum spaces, leading to reduced detection efficiency and increased maintenance needs.
Innovation Solution
A charged-particle beam apparatus with a light-generating surface, light-guiding member, photodetector, and light-transmission restricting member allows for adjustable light transmission outside the vacuum vessel, enabling precise signal discrimination by varying the opening shape and size of the light-transmission restricting member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed opening size is used in the light-transmission restricting member, then the device structure is simple, but the visibility of hole and groove bottom cannot be optimized for various observation samples
Solution Approach 1:
The light-transmission restricting member is made movable along the optical axis to dynamically adjust the opening size. This allows the system to adapt to different observation samples (holes, grooves, surfaces) by changing the aperture diameter, thereby optimizing visibility for various sample types without requiring multiple fixed apertures or complex switching mechanisms.
2Adaptability or versatility
If a movable mechanism is provided inside the vacuum vessel to adjust the opening size, then the adaptability is improved, but the device complexity and maintenance requirements increase
Solution Approach 1:
The movable mechanism for adjusting the opening size is extracted from the vacuum vessel and relocated to the external environment. The light-transmission restricting member can be adjusted from outside the vacuum chamber, eliminating the need for complex vacuum-compatible movable mechanisms inside the vacuum space. This reduces device complexity and maintenance requirements while preserving the adaptability to adjust opening size for different samples.
3Measurement precision
If a movable mechanism is provided to adjust the opening size, then the signal discrimination accuracy can be optimized, but the maintenance frequency increases
Solution Approach 1:
The movable mechanism is relocated outside the vacuum vessel, making it accessible for regular maintenance without requiring vacuum chamber opening or specialized vacuum-compatible components. This extraction approach maintains the ability to optimize signal discrimination accuracy through adjustable opening size while significantly reducing maintenance frequency and complexity by using standard mechanical components in the external environment.
4Measurement precision
If the light-transmission restricting member is placed inside the vacuum vessel, then the signal discrimination is improved, but the vacuum space utilization is reduced
Solution Approach 1:
The light-transmission restricting member is positioned outside the vacuum vessel, allowing the internal vacuum space to be fully utilized for sample placement and electron beam operations. The restricting member is placed in the external optical path where it can still perform signal discrimination by controlling the light cone angle, thereby maintaining measurement precision without consuming valuable vacuum space.
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
This configuration enhances signal discrimination accuracy and reliability, reduces maintenance requirements, and optimizes visibility of semiconductor device features without sacrificing processing speed.
Implementation Method 1
a light-guiding member for guiding the generated light to the outside of the vacuum vessel while maintaining the generation distribution of the light generated on the first light-generating surface
Implementation Method 2
a photodetector for detecting the light guided by the light-guiding member to the outside of the vacuum vessel
Data Source
AI summary
The purpose of the present invention is to provide a charged-particle beam apparatus capable of performing various types of signal discriminations according to the shape and the size of a sample. The present invention proposes a charged-particle beam apparatus for irradiating a sample disposed in a vacuum vessel with a charged particle beam. The charged-particle beam apparatus is provided with: a first light-generating surface for generating light on the basis of the collision of charged particles released from the sample; a light-guiding member for guiding the generated light to the outside of the vacuum vessel while maintaining the generation distribution of the light generated at the first light-generating surface; a photodetector for detecting the light guided by the light-guiding member to the outside of the vacuum vessel; and a light-transmission restricting member for restricting transmission of the light guided by the light-guiding member between the photodetector and the light-guiding member.