Semiconductor Defect Inspection via Optical-SEM Segmentation
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Solution Overview
Problem
Current defect inspection technologies in semiconductor manufacturing face challenges in accurately distinguishing between fatal and non-fatal defects, particularly with the miniaturization of patterns, where increased sensitivity leads to false detections and difficulty in understanding defect trends due to low resolution in optical inspection devices and the complexity of various defects generated in semiconductor manufacturing processes.
Innovation Solution
A method involving image capture, defect detection, circuit pattern recognition, computation of characteristic values related to grey values and shapes, filtering to extract specific defects or patterns, and displaying their distribution in a map format to visualize defect trends and circuit pattern changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If optical inspection is used to detect defects, then inspection speed and coverage are improved, but resolution is limited to several hundred nanometers making detailed defect analysis impossible
Solution Approach 1:
The inspection system is divided into two segments: an optical inspection device for rapid defect detection and an SEM-based observer for detailed defect analysis. The optical device captures low-resolution images to identify defect locations, then the SEM captures high-resolution images only of those specific locations, separating the functions of rapid screening and detailed analysis.
Solution Approach 2:
The optical inspection device acts as an intermediary that identifies defect locations, which then guide the SEM-based observer to capture detailed images. The coordinate information from optical inspection serves as a mediator to transfer the inspection task from low-resolution to high-resolution imaging.
2Productivity
If pixel size is increased to process images at high speed, then productivity is improved, but defect type identification becomes difficult due to reduced resolution
Solution Approach 1:
The system applies partial high-resolution imaging only to regions containing defects rather than processing the entire wafer at high resolution. The optical inspection identifies which areas need detailed analysis, and the SEM provides excessive detail only where necessary, avoiding the burden of processing all images at maximum resolution.
3Measurement precision
If multiple types of defects are detected without classification, then comprehensive defect detection is improved, but understanding defect trends and causes becomes difficult
Solution Approach 1:
The system uses visual classification by assigning different colors to different defect types in the displayed images. This allows operators to quickly understand defect distributions and trends through color-coded visualization, transforming detailed defect information into an easily interpretable visual format that preserves analytical capability.
Data Source
AI summary
Disclosed is a method of inspecting an object to be inspected in a semiconductor manufacturing process, for resolving the problem to increase defect detection sensitivity. An image capture means is used to image capture a designated area of the object to be inspected; a defect is detected in the captured image; a circuit pattern is recognized from the captured image; a characteristic value is computed, relating to an image tone and shape, from the detected defect; a characteristic value is computed, relating to the image tone and shape, from the recognized circuit pattern; either a specified defect or circuit pattern is filtered and extracted from the detected defect and the recognized circuit pattern; a mapping characteristic value is determined from the characteristic value of either the filtered and extracted specified defect or circuit pattern; and the distribution of the determined characteristic values is displayed onscreen in a map format.