Multi-Beam Inspection Crossover Deflector Array
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Solution Overview
Problem
Current pattern inspection tools with a single electron beam struggle to effectively detect defects and uninvited particles on semiconductor wafers, especially for advanced IC chips with smaller critical feature dimensions, leading to reduced yield.
Innovation Solution
A charged particle apparatus utilizing multiple charged particle beams, including a crossover-forming deflector array and a beam-limit aperture plate, to deflect and trim secondary electron beams, forming a crossover area for improved inspection and image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single electron beam is used for pattern inspection, then the device complexity is low, but the detection precision and productivity are insufficient for advanced IC chips with smaller critical feature dimensions
Solution Approach 1:
The patent divides a single electron beam system into multiple electron beams, with each beam independently scanning and detecting specific regions of the wafer. This segmentation enables parallel detection across multiple areas simultaneously, improving both detection precision and productivity while managing complexity through modular beam control
Solution Approach 2:
The patent combines multiple electron beams and their corresponding detection systems into a unified inspection apparatus. By merging the beams at a common detection stage and integrating their signals, the system achieves enhanced detection capability that surpasses individual beam performance while sharing common infrastructure to control complexity
2Productivity
If multiple charged particle beams are used to improve detection efficiency, then the productivity and detection precision improve, but the device complexity and beam control difficulty increase
Solution Approach 1:
The patent implements a universal control architecture that manages multiple electron beams through shared hardware and software resources. The detection system, signal processing chain, and data acquisition mechanisms serve all beams simultaneously, reducing the incremental complexity added by each additional beam while maintaining high detection efficiency
Solution Approach 2:
The patent introduces intermediary components such as beam combining optics and signal multiplexing devices that facilitate coordinated control of multiple beams. These intermediaries act as mediators between the independent beam sources and the unified detection system, simplifying the control architecture and reducing the complexity burden of managing multiple beams
3Reliability
If secondary electron beams are collected without crossover formation, then the system is simpler, but cross-talk between beams increases and collection efficiency uniformity decreases
Solution Approach 1:
The patent implements preliminary beam conditioning by forming crossovers of secondary electron beams before they reach the detection stage. This preliminary action of pre-aligning and pre-focusing the beams ensures that they converge at optimal points, reducing cross-talk and ensuring uniform collection efficiency across all beams while maintaining manageable system complexity
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
Enhances the detection efficiency and resolution of defects and uninvited particles on semiconductor wafers by creating a crossover area for secondary electron beams, reducing cross-talk and improving collection efficiency uniformity.
Implementation Method 1
a plurality of crossover-forming deflectors configured to create a crossover area on a crossing plane for the plurality of secondary electron beams
Implementation Method 2
generating a magnetic field to immerse a surface of the sample and projecting a plurality of primary electron beams onto the surface of the sample
Implementation Method 3
projecting, by a secondary imaging system, the plurality of secondary electron beams onto an electron detection device to obtain the images
Data Source
AI summary
The present disclosure proposes a crossover-forming deflector array of an electro-optical system for directing a plurality of electron beams onto an electron detection device. The crossover-forming deflector array includes a plurality of crossover-forming deflectors positioned at or at least near an image plane of a set of one or more electro-optical lenses of the electro-optical system, wherein each crossover-forming deflector is aligned with a corresponding electron beam of the plurality of electron beams.