Voltage Contrast Defect Detection with Dual-Mode Beam Control
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Solution Overview
Problem
Existing charged-particle beam inspection tools face challenges in maintaining high resolution and throughput due to increased Coulomb interaction effects when switching between flooding and inspection modes, which negatively impact imaging resolution and inspection efficiency.
Innovation Solution
A charged-particle beam apparatus with a movable aperture array and current-limiting aperture plate that adjusts beam current and focus based on operation mode, allowing for efficient switching between flooding and inspection modes without sacrificing resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the beam current is increased to improve throughput in flooding mode, then the inspection speed increases, but the Coulomb interaction effects increase which degrades the imaging resolution in inspection mode
Solution Approach 1:
The patent divides the charged particle beam into two separate portions using aperture arrays: a first portion for flooding the sample surface to generate voltage contrast, and a second portion for inspecting the sample. This segmentation allows each beam portion to be optimized independently - the first portion can have high current for effective flooding without affecting resolution, while the second portion maintains low current to minimize Coulomb interaction effects and preserve imaging resolution during inspection.
2Productivity
If the same tool parameters are kept unchanged between flooding and inspection modes to increase throughput, then the inspection speed improves, but the resolution deteriorates due to increased Coulomb interaction effects
Solution Approach 1:
The patent implements dynamic switching between different operational modes by controlling the condenser lens focusing. The system can switch between a first mode where the beam is focused for high-current flooding operation and a second mode where the beam is defocused for low-Coulomb interaction inspection operation. This dynamic adaptation allows the system to optimize for throughput during flooding while maintaining resolution during inspection, rather than being constrained to fixed parameters.
3Device complexity
If a single beam is used for both flooding and inspection, then the device complexity is reduced, but it is difficult to optimize both throughput and resolution simultaneously
Solution Approach 1:
The patent applies different properties to different portions of the beam using aperture arrays. The first aperture array creates a first portion of the beam with properties optimized for flooding (higher current, larger spot size), while the second aperture array creates a second portion with properties optimized for inspection (lower current, smaller spot size). This local differentiation within the single beam system allows each portion to have the specific characteristics needed for its intended function, achieving both throughput and resolution optimization without requiring completely separate beam systems.
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
The solution maintains high throughput and imaging resolution by minimizing Coulomb interaction effects, enabling effective defect detection in integrated circuits.
Implementation Method 1
a charged-particle source configured to generate a primary charged-particle beam along a primary optical axis
Implementation Method 2
a condenser lens configured to focus the at least a first portion of the primary charged-particle beam based on a selected mode of operation of the apparatus
Implementation Method 3
an aperture plate comprising a second aperture configured to form a second portion of the primary charged-particle beam
Implementation Method 4
electron microscope with enhanced imaging resolution and throughput by reducing Coulomb interaction effects between the charged particles of a charged particle beam
Data Source
AI summary
Systems and methods of providing a probe spot in multiple modes of operation of a charged-particle beam apparatus are disclosed. The method may comprise activating a charged-particle source to generate a primary charged-particle beam and selecting between a first mode and a second mode of operation of the charged-particle beam apparatus. In the flooding mode, the condenser lens may focus at least a first portion of the primary charged-particle beam passing through an aperture of the aperture plate to form a second portion of the primary charged-particle beam, and substantially all of the second portion is used to flood a surface of a sample. In the inspection mode, the condenser lens may focus a first portion of the primary charged-particle beam such that the aperture of the aperture plate blocks off peripheral charged-particles to form the second portion of the primary charged-particle beam used to inspect the sample surface.