Combined Overlay Metrology and Defect Inspection System
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional overlay metrology tools are expensive, slow, and limited in detecting variations within the die area, leading to potential misalignment and reduced device performance or failure in IC manufacturing due to inadequate precision and inability to detect localized overlay errors.
Innovation Solution
A combined overlay metrology and defect inspection system that uses imaging tools and computing hardware to compare mask images with design databases, determining database-to-mask offsets and identifying defects, thereby providing a mask overlay characteristic for precise alignment and error correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional overlay metrology tools are used to check mask alignment, then alignment verification is performed, but the tools are expensive, slow, and limited in detecting variations within the die area
Solution Approach 1:
The patent combines overlay metrology and defect inspection into a single integrated system. The inspection tool merges the functionality of separate overlay measurement devices and defect inspection devices, allowing both overlay variation detection and defect identification to be performed simultaneously using shared imaging and processing resources, thereby reducing device complexity while maintaining measurement precision
Solution Approach 2:
The inspection tool is designed with multi-functionality to perform both overlay metrology and defect inspection. By incorporating adjustable imaging parameters and flexible analysis modes, the single device can adapt to different measurement requirements (overlay alignment verification and defect detection), eliminating the need for multiple specialized tools and reducing overall system complexity
2Manufacturing precision
If conventional overlay metrology tools are used, then alignment checking is performed, but the process is slow and additional tools are needed
Solution Approach 1:
The system merges overlay metrology and defect inspection into a single operational workflow. By capturing images and performing both overlay analysis and defect detection in one inspection pass, the system eliminates the need for sequential processing with multiple tools, thereby improving productivity while maintaining manufacturing precision
Solution Approach 2:
The inspection tool performs continuous useful action by simultaneously executing overlay measurement and defect inspection during a single imaging sequence. The system processes both types of information from the captured images without interruption, maximizing productivity by eliminating idle time and redundant operations associated with separate inspection tools
3Measurement precision
If conventional overlay metrology tools are used, then overlay measurement is performed, but the ability to detect variations within the die area is limited
Solution Approach 1:
The inspection tool achieves universality by incorporating multiple detection capabilities within a single device. It can perform overlay measurement, defect inspection, and variation detection across different regions of the die area using the same imaging system, thereby enhancing adaptability while maintaining measurement precision through configurable analysis parameters
Solution Approach 2:
The system applies local quality by enabling region-specific analysis modes. Different areas of the die can be inspected with customized parameters - overlay-critical regions receive precise alignment verification while other areas undergo defect screening, allowing the system to adapt its detection capabilities to local requirements and enhance overall versatility
Data Source
AI summary
A method and system for measuring layer overlay and for inspecting a mask for defects unrelated to overlay utilizing a singe comprehensive tool is disclosed. An exemplary method includes receiving a mask design database that corresponds to a mask and has a die area with a mask database feature. A mask image of the mask is received, and a comprehensive inspection system compares the mask image to the mask design database in order to detect mask defects that are not related to layer alignment. The system produces mask defect information corresponding to the mask defects. The comprehensive inspection system also compares the mask image to the mask design database to determine a database-to-mask offset. From the database-to-mask offset, a mask overlay characteristic is determined.