E-beam Inspection Dual-Deflection System for Wafer Defect Localization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional e-beam defect inspection tools for semiconductor wafers face limitations in effectively detecting defects, particularly in terms of signal-to-noise ratio and efficiency in scanning large areas, leading to suboptimal defect localization and imaging.
Innovation Solution
The use of a charged particle column with a dual-deflection system, including magnetic and electrostatic deflection components, to precisely focus and move an e-beam over predetermined locations on the wafer, combined with a negative bias circuit to control landing energy and accelerate secondary electrons, and a detector within the focusing column to enhance signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional e-beam defect inspection tools scan large areas of semiconductor wafers, then coverage area increases, but signal-to-noise ratio deteriorates leading to suboptimal defect localization
Solution Approach 1:
The patent divides the large scan area into multiple smaller regions of interest (ROIs) or tiles. The e-beam inspection is performed sequentially on each tile rather than attempting to scan the entire large area in one pass. This segmentation allows the system to maintain high signal-to-noise ratio on each small tile while achieving complete coverage of the large area through multiple passes, effectively resolving the contradiction between scan area and measurement precision.
2Area of stationary object
If conventional e-beam defect inspection tools scan large areas, then coverage area increases, but inspection time increases reducing efficiency
Solution Approach 1:
The patent performs preliminary actions by first identifying regions of interest (ROIs) or defective areas before conducting detailed e-beam inspection. Low-resolution screening or defect mapping is performed first to locate potential defect areas, then the high-resolution e-beam inspection is applied only to these pre-identified regions. This preliminary action eliminates the need to scan entire large areas with the time-consuming high-resolution e-beam, thereby maintaining complete area coverage while dramatically improving inspection efficiency.
3Measurement precision
If e-beam is focused on predetermined locations using dual-deflection system, then defect localization precision improves, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical positioning systems with electromagnetic field-based deflection systems. Instead of physically moving the e-beam column or sample stage using mechanical actuators, the system uses magnetic and electrostatic fields to deflect and position the electron beam precisely at predetermined locations. This substitution of mechanical systems with electromagnetic fields achieves high precision defect localization while reducing mechanical complexity, though it introduces electromagnetic control 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
This approach significantly improves the detection of defects by increasing the signal-to-noise ratio and enabling faster scanning of large areas, allowing for more precise and efficient defect localization and imaging on semiconductor wafers.
Implementation Method 1
a magnetic deflection component that provides by magnetic deflection for movement of the e-beam through a plurality of areas on the integrated circuit
Implementation Method 2
an electrostatic deflection component that provides by electrostatic deflection for movement of the e-beam within each of the plurality of areas and placement of the e-beam at each of particular ones of the plurality of predetermined locations
Implementation Method 3
a negative bias circuit that provides a negative bias between the objective lens and the target holder, the negative bias serving to (1) decelerate the e-beam so that the e-beam strikes the integrated circuit with a landing energy having a predetermined range
Implementation Method 4
a negative bias circuit that provides a negative bias between the objective lens and the target holder, the negative bias serving to (1) decelerate the e-beam so that the e-beam strikes the integrated circuit with a landing energy having a predetermined range, and (2) accelerate secondary electrons emitted from the integrated circuit
Implementation Method 5
a detector that detects a voltage contrast image of the secondary electrons emitted from the integrated circuit after the e-beam strikes each of the plurality of predetermined locations of the integrated circuit
Data Source
AI summary
The present invention discloses an e-beam inspection tool, and an apparatus for detecting defects. In one aspect is described an apparatus for detecting defects that includes a dual-deflection system that moves the e-beam over the integrated circuit to each of the plurality of predetermined locations, the dual deflection system including a magnetic deflection component that provides by magnetic deflection for movement of the e-beam through a plurality of areas on the integrated circuit and an electrostatic deflection component that provides by electrostatic deflection for movement of the e-beam within each of the plurality of areas.