Movable Conductive Ring for Wafer Edge Beam Inspection
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Solution Overview
Problem
Conventional charged particle beam inspection systems face challenges with distorted electric fields near the wafer edge due to gaps between the conductive ring and the wafer, leading to defocusing, deflection, and distortion of the electron beam, which affects image quality and can result in errors during wafer inspection.
Innovation Solution
A system with a conductive ring having movable segments that can be adjusted radially inward to minimize the gap with the wafer edge and be set to the same electric potential as the wafer, ensuring a uniform electric field across the conductive ring and the wafer, thereby eliminating distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a conductive ring is used to maintain electric potential during wafer inspection, then the electric field stability is improved, but image quality deteriorates due to distorted electric fields near the wafer edge caused by gaps between the conductive ring and wafer
Solution Approach 1:
The conductive ring is divided into multiple movable segments that can be independently adjusted. This segmentation allows each segment to be positioned close to the wafer edge without requiring the entire ring to be in contact, thereby reducing the gap-induced distortion while maintaining electric field stability through coordinated segment positioning
Solution Approach 2:
The conductive ring segments are made movable rather than fixed, allowing dynamic adjustment of the ring-wafer gap. The segments can be radially adjusted to optimize the distance from the wafer edge, enabling the system to adapt to different wafer sizes and inspection requirements while minimizing electric field distortion
2Measurement precision
If the conductive ring is placed close to the wafer edge to reduce gap distortion, then image quality is improved, but the risk of contact and potential damage increases
Solution Approach 1:
The conductive ring segments are designed with movable capabilities that allow precise control of the distance between the ring and wafer edge. This dynamic positioning enables the system to maintain an optimal gap that is small enough to reduce electric field distortion but large enough to prevent contact and potential damage
Solution Approach 2:
The system incorporates feedback mechanisms to monitor the position and voltage of the conductive ring segments relative to the wafer. This feedback allows real-time adjustments to maintain the optimal gap distance, preventing contact while ensuring image quality through minimized electric field distortion
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 solution improves the imaging capabilities near the wafer edge by maintaining a uniform electric field, reducing errors and enhancing the accuracy of wafer inspection processes.
Implementation Method 1
adjusting a voltage applied to the conductive ring to enable the voltage applied to the conductive ring to be substantially equal to the voltage applied to the wafer to provide a substantially consistent electric field across an inner portion of the conductive ring and an outer portion of the wafer
Data Source
AI summary
An improved method of wafer inspection is disclosed. The improved method includes a non-transitory computer-readable medium storing a set of instructions that are executable by at least one processor of a device to cause the device to perform a method comprising: placing the wafer at a location on a stage; moving one or more movable segments of a conductive ring inward in a radial direction to enable the conductive ring to be within a predetermined distance from an edge of the wafer; and adjusting a voltage applied to the conductive ring or to a voltage applied to the wafer so that to enable the voltage applied to the conductive ring to be substantially equal to the voltage applied to the wafer to provide a substantially consistent electric field across an inner portion of the conductive ring and an outer portion of the wafer.