Wafer Surface Feature Detection with 3D Defect Metrology
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Solution Overview
Problem
Existing wafer inspection tools cannot provide defect height, depth, or volume information, limiting their ability to quantify the impact of surface defects on wafer quality.
Innovation Solution
A method and system for wafer surface feature detection, classification, and quantification that involves data acquisition, filtering to improve signal-to-background contrast, edge treatment, defect detection, and calculation of defect height, depth, area, and volume using surface fitting techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If existing wafer inspection tools are used, then surface defect detection is achieved, but defect height, depth, and volume information is not provided
Solution Approach 1:
The patent transitions from two-dimensional surface inspection to three-dimensional defect characterization by incorporating height and depth measurements. The system uses optical interferometry to capture phase information, converting 2D intensity images into 3D surface topography data, enabling volume calculation and comprehensive defect metrology.
Solution Approach 2:
The patent introduces an optical interferometer as an intermediary device between the wafer surface and the detection system. This interferometer captures phase shifts caused by surface defects, translating physical height variations into measurable optical path differences, thereby enabling indirect measurement of defect dimensions.
2Measurement precision
If comprehensive defect metrology is implemented, then defect characterization is improved, but system complexity increases
Solution Approach 1:
The patent integrates multiple measurement functions into a single inspection system. The same optical system that captures surface images also measures height and depth by analyzing phase information. This multi-functionality eliminates the need for separate profilometers or confocal microscopes, reducing overall system complexity while maintaining comprehensive measurement capabilities.
Solution Approach 2:
The patent replaces mechanical contact measurement methods with optical interferometry. Instead of using physical probes to scan the wafer surface, the system uses light wave interference patterns to non-contactly measure surface topography, thereby eliminating mechanical complexity while achieving high-precision 3D defect characterization.
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 comprehensive defect metrology by reporting critical defect dimensions, enhancing the assessment of wafer quality and production processes.
Implementation Method 1
an optical system configured for acquiring a wafer surface image
Implementation Method 2
filtering the wafer surface image to improve signal to background contrast
Implementation Method 3
calculating at least one of: a height, a depth, an area and a volume of the defect utilizing surface fitting
Data Source
AI summary
Systems and methods for providing micro defect inspection capabilities for optical systems such as wafer metrology tools and interferometer systems are disclosed. The systems and methods in accordance with the present disclosure may detect, classify and quantify wafer surface features, wherein the detected defects are classified and the important defect metrology information of height/depth, area and volume is reported. The systems and methods in accordance with the present disclosure therefore provide more values for quantifying the negative effect of these defects on the wafer quality.