Electron Beam NCEM Alignment on a Moving Wafer Stage
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Solution Overview
Problem
The movement of a semiconductor wafer or device under test on a movable stage introduces uncertainty in the testing process, leading to throughput delays and errors due to difficulty in precisely determining the position of the wafer before, during, and after movement, especially during non-contact electrical measurements using particle or electron beams.
Innovation Solution
A system and method for performing non-contact electrical measurements on a moving NCEM-enabled cell vehicle by adjusting the deflection angle of a charged particle beam, such as an electron beam, in response to the continuous or varying movement of the stage, using position assessment hardware to compensate for stage movement, allowing continuous testing without stopping the stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the stage moves the cell vehicle to facilitate beam incidence on different targets, then the coverage and completeness of testing is improved, but the position determination accuracy deteriorates due to movement uncertainty
Solution Approach 1:
The system employs position assessment hardware to continuously monitor the stage position and feeds this information back to the control system. This feedback loop enables real-time compensation for position uncertainties, allowing the system to maintain measurement precision while the stage is in motion during NCEM testing.
Solution Approach 2:
The patent replaces reliance on purely mechanical position stopping with a combination of mechanical movement and electronic/optical position assessment. By using position assessment hardware (optical/electronic systems) to track and compensate for stage position, the system substitutes mechanical precision requirements with electronic measurement and compensation capabilities.
2Measurement precision
If the stage stops to position the cell vehicle precisely under the beam, then the position accuracy is improved, but the testing throughput deteriorates due to repeated stopping and starting
Solution Approach 1:
The system transitions from a static testing approach (stop-move-stop) to a dynamic approach where the stage continues moving during measurement. The position assessment hardware dynamically tracks the stage position in real-time, enabling accurate measurements to be taken while the stage is in motion, thus eliminating the need for repeated stopping and starting.
Solution Approach 2:
The patent enables continuous stage movement throughout the testing process by implementing real-time position compensation. The useful action of testing continues uninterrupted while the stage moves, rather than being interrupted by stopping and starting operations, thereby maintaining both position accuracy and high throughput.
3Measurement precision
If the electron beam deflection angle is adjusted in response to stage movement, then the alignment accuracy during movement is improved, but the system complexity increases due to real-time adjustment mechanisms
Solution Approach 1:
The position assessment hardware serves multiple functions: it tracks stage position, calculates position deviations, and provides compensation data for beam alignment. This multi-functional component reduces the need for separate systems for each function, thereby managing system complexity while achieving high alignment accuracy during stage movement.
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 increases throughput and reduces yield loss by enabling precise positioning and alignment of the electron beam during testing, even when the cell vehicle is moving, thereby improving the accuracy and speed of semiconductor device inspections.
Implementation Method 1
A response of the target to the particle beam may be detected and analyzed to determine, for example, whether the target's response to the particle beam is correct and/or indicates whether the target is operational and/or defective.
Implementation Method 2
using position assessment hardware to compensate for stage movement
Data Source
AI summary
Systems, devices, and methods for performing a non-contact electrical measurement (NCEM) on a NCEM-enabled cell included in a NCEM-enabled cell vehicle may be configured to perform NCEMs while the NCEM-enabled cell vehicle is moving. The movement may be due to vibrations in the system and/or movement of a movable stage on which the NCEM-enabled cell vehicle is positioned. Position information for an electron beam column producing the electron beam performing the NCEMs and/or for the moving stage may be used to align the electron beam with targets on the NCEM-enabled cell vehicle while it is moving.