Charged Particle Metrology System for Sub-Micron Critical Dimension Measurement
Solution Overview
Problem
Current metrology systems face challenges in accurately measuring sub-micron structural elements due to mechanical inaccuracies and the shrinking size of features in integrated circuits, which affects the precision of critical dimension measurements.
Innovation Solution
A measurement model and system that includes a scanner for charged particles, a detector for signal processing, and a processor to utilize measurement image information for locating and measuring structural elements, incorporating edge information and alternative measurement options to enhance accuracy and simplify edge detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If charged particle beam imaging is used to measure sub-micron structural elements, then measurement precision is improved, but mechanical inaccuracies and positioning errors affect the reliability of measurements
Solution Approach 1:
The system uses a measurement model containing reference images and actual measurement images to continuously compare and adjust positioning. The processor compares edge locations from reference images with actual measurements, generating feedback to correct positioning deviations and improve measurement reliability
Solution Approach 2:
The system performs preliminary positioning by locating targets and identifying measurement areas before actual critical dimension measurements are taken. Reference images are prepared in advance with known edge locations, allowing the system to pre-establish a measurement framework that compensates for mechanical inaccuracies
2Measurement precision
If multiple measurement stages are implemented to locate and measure structural elements, then measurement accuracy is improved, but device complexity and measurement time increase
Solution Approach 1:
The system merges reference image data with actual measurement images into a single measurement model. Multiple measurement stages (target location, area identification, edge detection) are integrated into one unified process that uses the measurement model to guide all operations, reducing overall system complexity
Solution Approach 2:
The measurement model serves multiple functions simultaneously: it stores reference images, provides positioning information, contains edge location data, and guides measurement operations. This multi-functional approach eliminates the need for separate systems for each measurement stage
3Productivity
If traditional edge detection methods are used in shrinking features, then measurement capability is maintained, but measurement precision deteriorates due to mechanical inaccuracies
Solution Approach 1:
The system uses feedback from comparing actual edge locations with reference edge locations to correct measurement errors. The processor continuously refines edge detection by comparing measurements against the measurement model, compensating for mechanical inaccuracies in shrinking features
Solution Approach 2:
The system creates a digital copy of the measurement area through reference images that contain ideal edge locations. This reference copy is used to compare against actual measurements, allowing the system to identify and correct deviations caused by mechanical inaccuracies in measuring shrinking features
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
The system improves measurement accuracy and repeatability by using a measurement model that includes reference images and edge information, reducing mechanical inaccuracies and simplifying the measurement process, thereby enhancing the precision of critical dimension measurements in sub-micron structural elements.
Implementation Method 1
a scanner for scanning an measurement area with a beam of charged particles
Implementation Method 2
a detector, positioned to receive charged particles resulting from an interaction between the measurement area and the beam of charged particles and to provide multiple detection signals
Data Source
AI summary
The invention provides a method and a measurement system. The method includes: providing a measurement model that includes measurement image information; locating a measurement area image area by utilizing the measurement image information; and performing at least one measurement to provide measurement result information.