Registration Cell Beam Alignment for Moving Wafer Inspection
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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, allowing continuous or incremental positioning of tiles under an electron beam column, adjusting the beam's deflection angle to maintain accuracy while the stage is moving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a movable stage is used to position the semiconductor wafer for particle beam inspection, then the inspection coverage area 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 object between the particle beam system and the movable stage. The registration cell contains known geometric features that serve as a mediator to establish precise positional relationships, allowing the system to compensate for stage movement uncertainty and achieve accurate position determination even during stage motion
Solution Approach 2:
The registration cell creates a known geometric copy or reference model of position relationships. By comparing the actual particle beam positions against the known registration cell geometry, the system can determine precise positions despite stage movement, effectively using the registration cell as a positional reference copy
2Productivity
If the stage moves continuously during particle beam inspection, then the inspection throughput is improved, but the testing accuracy deteriorates due to position uncertainty
Solution Approach 1:
The system uses the registration cell to provide continuous feedback on the actual positions of features during stage movement. By constantly referencing the known registration cell geometry, the system can dynamically adjust and maintain accurate position determination throughout continuous stage motion, enabling both high throughput and high accuracy
Solution Approach 2:
The registration cell is prepared in advance with precisely known geometric features before the inspection process begins. This preliminary establishment of reference positions allows the system to quickly and accurately determine feature positions during continuous stage motion without requiring stopping or recalibration
3Speed
If the particle beam is used to perform non-contact electrical measurement on moving targets, then the inspection speed is improved, but the measurement accuracy deteriorates due to motion-induced position errors
Solution Approach 1:
The registration cell serves as a mediator that links the moving stage to the particle beam measurement system. By providing known reference features that can be identified during motion, it enables the system to calculate and compensate for position errors, maintaining measurement accuracy while allowing continuous stage movement at high speeds
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 testing accuracy and throughput by precisely aligning the electron beam with moving targets, reducing yield loss and improving the speed of chip, wafer, or die inspection.
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
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.