Defect Inspection Device Dynamic Rotation Scanning
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Solution Overview
Problem
Current defect inspection devices in semiconductor manufacturing face challenges in achieving high sensitivity and speed, particularly in detecting finer defects on the outer peripheral portion of wafers, due to limitations in sensitivity and the trade-off between high sensitivity and fast inspection time.
Innovation Solution
A defect inspection device that spirally or concentrically scans a rotating sample with illumination light, using a combination of a rotary stage and a rectilinear stage, where scanning starts without waiting for the stage to reach a specified rotation speed, allowing for extended scanning time and improved sensitivity by controlling the linear and angular velocities to maximize irradiation time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the stage rotation speed is increased to shorten inspection time, then productivity improves, but measurement precision deteriorates due to reduced irradiation time per point
Solution Approach 1:
The patent applies dynamics by making the rotation speed variable rather than constant. The rotation speed is dynamically adjusted based on the radial position: slower at the outer periphery where longer irradiation time is needed for high sensitivity, and faster at the inner periphery where shorter irradiation time is acceptable. This dynamic speed adjustment resolves the contradiction between inspection speed and detection sensitivity.
Solution Approach 2:
The patent changes the parameter of rotation speed according to the scanning position. By modifying the rotation speed parameter dynamically during the inspection process, the system achieves both high productivity (through overall fast inspection) and high measurement precision (through extended irradiation time at critical outer peripheral regions).
2Measurement precision
If the optical system approaches the wafer closer to enhance sensitivity, then measurement precision improves, but device complexity increases due to space constraints and alignment requirements
Solution Approach 1:
The patent replaces the mechanical approach of physically moving the optical system closer with a rotational scanning mechanism. Instead of reducing the distance between the optical system and wafer, the system uses rotational movement to bring different areas of the wafer sequentially under the fixed optical system, achieving high sensitivity without the complexity of close-proximity optical configuration.
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 reduces waiting time associated with stage rotation acceleration/deceleration, shortens inspection processing time, and enhances sensitivity, especially at the outer peripheral areas of the wafer, enabling more effective detection of finer defects.
Implementation Method 1
a detection optical system for detecting inspection light scattered or reflected by the sample
Implementation Method 2
a detection optical system for detecting inspection light scattered or reflected by the sample
Data Source
AI summary
This defect inspection device for emitting illumination light onto a moving and rotating sample and inspecting for sample defects by scanning the sample in a spiral shape or concentric circle shapes comprises: an illumination and detection unit comprising an emission optical system and a detection optical system; a rotary stage for rotating the sample; a rectilinear stage for rectilinearly moving the rotary stage; and a controller for controlling the illumination and detection unit, rotary stage, and rectilinear stage. On the linear path of the rectilinear stage are a scanning start position where illumination light is emitted onto the sample and scanning is started and a sample delivery position where movement of the sample to the scanning start position starts. When the sample arrives at the scanning start position, the defect inspection device starts emitting the illumination light onto the sample without waiting for the rotation speed of the rotary stage to rise to a specified rotation speed for scanning and raises the rotation speed of the rotary stage to the specified rotation speed while scanning the sample.