Modular Disk Inspection Apparatus for Wafer Edge and Surface Defect Detection
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Solution Overview
Problem
Existing apparatuses for inspecting disk-like objects, such as semiconductor wafers, are unable to perform a full inspection without increasing the system's footprint, particularly failing to inspect edge areas, test fields, and non-structured regions, which are critical for early defect detection and preventing defects from propagating to productive dies.
Innovation Solution
A modular apparatus that integrates multiple inspection modules, including macro- and micro-inspection capabilities, with a rotary table for rotating the disk-like object, allowing for simultaneous inspection of structured surfaces, edge areas, back surfaces, and central areas using a combination of scanning and light-receiving means connected via links for efficient data transmission and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate devices are used for edge inspection (as in JP 09269298 A), then edge area inspection capability is improved, but device complexity and footprint increase
Solution Approach 1:
The patent combines multiple inspection modules (macro-inspection module, micro-inspection module, edge inspection module) into a single integrated apparatus. The edge inspection module is merged with the rotary table system, allowing all inspection functions to be performed by one unified device rather than separate standalone devices, thereby reducing overall system footprint while maintaining comprehensive inspection capability.
Solution Approach 2:
The inspection apparatus is designed as a multi-functional system where a single apparatus performs multiple inspection tasks: macro-inspection of structured surfaces, micro-inspection of specific features, and edge area inspection. The rotary table and optical systems are configured to handle different inspection modes, making the device universal and eliminating the need for multiple specialized devices.
2Measurement precision
If die-to-die comparison method is used (as in US 2004/0105578 A1), then macroscopic defect detection is improved, but inspection coverage is limited to productive dies only
Solution Approach 1:
The wafer inspection is divided into distinct segments handled by different modules: the macro-inspection module handles productive dies using die-to-die comparison, while the edge inspection module specifically targets edge areas, test fields, and non-structured regions. This segmentation allows each module to optimize for its specific inspection task, achieving both precision and comprehensive coverage.
Solution Approach 2:
The inspection system extends beyond the traditional two-dimensional die-to-die comparison by adding a third dimension of inspection coverage through the edge inspection module. This module inspects the peripheral regions and edge areas that were previously excluded, effectively expanding the inspection space from the central productive area to include the entire wafer perimeter and edge regions.
3Productivity
If edge areas are not inspected, then productivity is maintained, but defect detection capability deteriorates
Solution Approach 1:
The edge inspection module performs preliminary inspection of edge areas and test fields before the wafer proceeds to full processing. By detecting defects early in the edge regions where problems first appear, the system prevents defective wafers from continuing through the production line, thereby maintaining overall productivity by avoiding rework or scrap later in the process.
Solution Approach 2:
The rotary table serves as an intermediary mechanism that coordinates between the macro-inspection module and the edge inspection module. It enables seamless transition and integration of inspection data from different modules, allowing the system to maintain high throughput by efficiently managing the inspection workflow across multiple functional areas without creating bottlenecks.
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
Enables a comprehensive, integral inspection of disk-like objects without increasing the apparatus' footprint, allowing for early detection of defects near the wafer edge and in non-structured areas, thereby preventing defects from affecting productive dies.
Implementation Method 1
evaluating light beams reflected from the surface of the wafer
Implementation Method 2
inspecting the edge area with diffracted light
Data Source
AI summary
An apparatus for inspecting a disk-like object comprising at least one first module for inspecting a surface of the disk-like object and at least one second module insertable in the apparatus. The at least one second module is arranged to inspect a different element of the disk-like object than the surface of the disk-like object.