Charged-Particle Probe Spot Scanning for High-Throughput Inspection
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Solution Overview
Problem
Current inspection techniques for device manufacturing, such as optical inspection and charged particle beam inspection, face challenges in achieving high throughput and precision due to interactions among charged particles, particularly in the context of smaller pattern dimensions on substrates and patterning devices.
Innovation Solution
The use of multiple beams of charged particles, where the optical system simultaneously moves probe spots in two directions while the sample is moved in one direction, and then adjusts the probe spots' position relative to the sample to optimize inspection coverage and reduce mechanical hysteresis, employing a combination of lenses, deflectors, and source-conversion units to form multiple probe spots for enhanced inspection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single beam of charged particles is used for inspection, then the interaction among charged particles is minimized, but the inspection throughput and coverage area are limited
Solution Approach 1:
The optical system is divided into multiple independent beam generation units, each producing a separate probe spot. This segmentation allows parallel inspection of multiple areas simultaneously, increasing throughput while keeping each individual beam unit relatively simple
Solution Approach 2:
Multiple beam units are merged into a single optical system that can generate and control multiple probe spots. The combined system achieves high throughput by inspecting multiple locations in parallel, while the modular architecture prevents excessive complexity
2Measurement precision
If the probe spot size is reduced to improve resolution, then the inspection precision increases, but the mechanical hysteresis and positioning accuracy requirements increase
Solution Approach 1:
The inspection area is segmented into multiple zones covered by different probe spots. By distributing the inspection task across multiple spots rather than moving a single small spot, the system achieves high resolution without requiring excessive mechanical positioning movements
Solution Approach 2:
The optical system replaces mechanical movement with optical scanning to position probe spots. Multiple probe spots can be positioned and moved independently through optical deflection rather than mechanical stage movement, reducing mechanical hysteresis effects and improving positioning speed
3Productivity
If multiple beams of charged particles are used simultaneously, then the inspection coverage area and throughput increase, but the interactions among charged particles increase
Solution Approach 1:
The multiple beams are segmented into spatially separated probe spots that operate independently. This segmentation reduces the density of charged particles in each spot, minimizing interactions while maintaining high overall throughput through parallel operation
Solution Approach 2:
Each probe spot maintains optimal local beam quality with controlled current density. By distributing the total beam current across multiple spots rather than concentrating it in one spot, the system achieves high throughput without excessive particle interactions at any single location
4Productivity
If the scanning speed is increased to improve throughput, then the inspection coverage rate increases, but the mechanical hysteresis and positioning accuracy deteriorate
Solution Approach 1:
The scanning task is segmented across multiple probe spots that can operate in parallel. This allows the system to achieve high coverage rates without requiring any single spot to move excessively fast, thereby maintaining positioning accuracy
Solution Approach 2:
The system uses optical scanning mechanisms to position multiple probe spots rather than relying solely on mechanical stage movement. This substitution enables faster repositioning with less mechanical hysteresis, improving both throughput and positioning accuracy
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 approach enhances inspection resolution and throughput by minimizing interactions among charged particles, allowing for more efficient scanning and coverage of larger areas with improved precision and reduced mechanical limitations, thereby improving the yield and accuracy of device manufacturing processes.
Implementation Method 1
a source configured to emit charged particles; wherein the optical system is configured to form probe spots on the sample with the charged particles
Implementation Method 2
move the probe spots by the first distance less a width of one of the probe spots in an opposite direction of the first direction
Data Source
AI summary
Disclosed herein is an apparatus comprising: a source configured to emit charged particles, an optical system and a stage; wherein the stage is configured to support a sample thereon and configured to move the sample by a first distance in a first direction; wherein the optical system is configured to form probe spots on the sample with the charged particles; wherein the optical system is configured to move the probe spots by the first distance in the first direction and by a second distance in a second direction, simultaneously, while the stage moves the sample by the first distance in the first direction; wherein the optical system is configured to move the probe spots by the first distance less a width of one of the probe spots in an opposite direction of the first direction, after the stage moves the sample by the first distance in the first direction.