CD-SAXS Defect Classification for Microelectronic Test Patterns
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Solution Overview
Problem
Existing methods for measuring defects in microelectronic components' control patterns, such as overlay and deformation, are complex and time-consuming due to the need to consider multiple parameters, leading to inefficient data acquisition and analysis.
Innovation Solution
A simplified method using CD-SAXS to identify defects by analyzing symmetries in diffraction patterns, classifying defects into six cases based on translational and deformation angles, allowing quick identification and adjustment of manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple parameters are considered to describe potential defects in the control pattern, then the measurement precision and completeness of defect characterization is improved, but the device complexity and time-consuming nature of data acquisition and analysis increases
Solution Approach 1:
The patent segments the defect analysis process into distinct symmetry classes (six classes based on presence/absence of overlay and deformation). By dividing the continuous parameter space into discrete symmetry-based categories, the complex multi-parameter analysis is broken down into manageable segments that can be analyzed independently, reducing overall system complexity while maintaining measurement precision.
Solution Approach 2:
The patent extracts and analyzes only the essential symmetry properties of the diffraction pattern rather than processing all possible geometric parameters. By taking out and focusing solely on symmetry characteristics (which capture the essential defect information), the method eliminates redundant parameters and simplifies the analysis model while preserving the ability to accurately characterize defects.
2Loss of information
If multiple parameters are considered to describe potential defects, then the completeness of defect information is improved, but the time required for data acquisition and analysis increases
Solution Approach 1:
The patent performs preliminary classification of defects based on symmetry properties before detailed parameter measurement. By preliminarily identifying which symmetry class a defect belongs to, the system can then focus data acquisition and analysis only on the specific parameters relevant to that class, avoiding the time-consuming collection and analysis of all possible parameters for every defect type.
Solution Approach 2:
The patent applies partial action by measuring only the subset of parameters necessary for each symmetry class rather than all possible parameters. For example, if a defect is classified as having no overlay and no deformation, only the essential confirming measurements are taken, rather than comprehensively measuring all geometric parameters, thus reducing analysis time while maintaining information completeness.
3Manufacturing precision
If a complex model with multiple parameters is used for three-dimensional reconstruction of line shapes, then the manufacturing precision control is improved, but the productivity of the measurement process deteriorates
Solution Approach 1:
The patent introduces dynamics by adapting the measurement and analysis approach based on the symmetry class identified. Rather than using a fixed complex model for all cases, the system dynamically selects the appropriate level of modeling complexity based on the defect type, using simpler models when sufficient and more detailed models only when necessary, thus optimizing both precision control and measurement productivity.
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 rapid and accurate classification of defects, facilitating precise manufacturing adjustments and improving production line efficiency by guiding appropriate analysis methods and equipment realignment.
Implementation Method 1
measurement methods by small angle X-ray scattering - CD-SAXS (Critical-Dimension Small Angle X-ray Scattering)
Implementation Method 2
measuring the defects affecting the control pattern
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A method for identifying (100) a defect affecting a control pattern carried by a microelectronic component and resulting from the superposition of a first array of lines and a second array of lines. The method, which employs a small-angle X-ray scattering technique, comprises the steps of: acquiring (105), by illuminating the control pattern, a plurality of intensity measurements of a transmitted or reflected X-ray beam for a plurality of X-ray beam incidence angles to reconstruct, from the plurality of intensity measurements, at least two Bragg rods of order n and -n of a diffraction pattern; and applying (110, 120, 130, 140) a plurality of tests (Q1, Q2, Q3, Q4) to the diffraction pattern to determine the type of defect affecting the control pattern.