Particle Beam Alignment Using Registration Cells on Moving Stages
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Solution Overview
Problem
The movement of a semiconductor wafer or device under test on a movable stage introduces uncertainty in determining its precise position, leading to throughput delays and errors during particle beam inspection processes.
Innovation Solution
A non-contact electrical measurement system aligns a particle beam using a registration cell to compensate for stage movement, adjusting the beam's deflection angle based on real-time position information to ensure accurate testing of moving NCEM-enabled cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the wafer/DUT is positioned on a movable stage to enable testing of different regions, then the inspection coverage is improved, but the position determination precision deteriorates due to stage movement uncertainty
Solution Approach 1:
A registration cell is introduced as an intermediary reference structure on the stage. This registration cell contains known geometric features that serve as a mediator between the moving stage and the fixed particle beam column, enabling precise position determination despite stage movement
Solution Approach 2:
The patent replaces reliance on mechanical stage position encoding with an optical/image-based recognition system. By capturing images of the registration cell and analyzing its features, the system determines position optically rather than mechanically, eliminating stage movement uncertainty
2Measurement precision
If the particle beam is used for inspection, then the measurement capability is improved, but the yield loss increases due to exposure of functional components
Solution Approach 1:
The wafer is divided into functional cells, with specific non-functional cells designated as registration cells. This segmentation allows the particle beam to be directed at registration cells for positioning without exposing sensitive functional components to damaging radiation
Solution Approach 2:
The registration cell acts as an intermediary target that absorbs the particle beam exposure intended for positioning purposes, protecting functional components from direct beam exposure while still enabling precise measurement and alignment
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 allows for precise electrical measurements on moving cells, increasing throughput and reducing yield loss by minimizing exposure of functional components to the particle beam.
Implementation Method 1
The NCEM measurements may be performed using a particle beam, such as an electron beam, that is projected toward a target on the NCEM-enabled cell vehicle. A response of the target to the particle beam may be detected and analyzed
Implementation Method 2
adjusting the beam's deflection angle based on real-time position information to ensure accurate testing of moving NCEM-enabled cells
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.