XPS Film Measurement in Small Boxes Using Multi-Beam Signal Separation
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Solution Overview
Problem
Existing X-ray photoelectron spectroscopy (XPS) methods struggle to accurately measure the thickness and composition of film layers in small boxes due to X-ray beam spillage outside the box region, making it difficult to distinguish signals from within and around the box.
Innovation Solution
Implementing multiple XPS measurements with different beam sizes to determine the mixing fraction of the beam inside and outside the box, using attenuation models to calculate the thickness and composition of the film layer within the box.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a standard X-ray beam is used for XPS measurement, then the measurement process is simple, but the beam size is larger than the box region causing signal spillage and reducing measurement precision
Solution Approach 1:
The measurement process is segmented into multiple measurements using different beam sizes. A first measurement is performed with a beam size larger than the box region to capture both box and surrounding area signals, while a second measurement is performed with a beam size matching the box region to capture only box signals. This segmentation allows separate characterization of box and surrounding area contributions, resolving the signal spillage problem while maintaining operational feasibility.
Solution Approach 2:
The method intentionally uses a beam size that exceeds the box region boundaries for the first measurement. This excessive action deliberately captures signals from both the box region and surrounding areas, which then allows for mathematical separation of these contributions through comparison with the second measurement, ultimately achieving precise box region characterization.
2Measurement precision
If the X-ray beam size is reduced to fit inside the box region, then measurement precision improves, but the beam may not cover the entire box region and measurement reliability decreases
Solution Approach 1:
The methodology segments the measurement into two distinct beam size measurements. The first measurement uses a larger beam to ensure complete coverage of the box region, providing reliable total signal data. The second measurement uses a smaller beam focused on the box region for precise signal separation. This segmented approach ensures both complete coverage and precise discrimination.
Solution Approach 2:
The method uses feedback from the first measurement (larger beam) to inform the interpretation of the second measurement (smaller beam). By comparing the signals from both measurements and calculating the difference, the system dynamically determines the box region film layer properties, ensuring reliable and consistent results through cross-validation.
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
Accurately determines the thickness and composition of film layers in small boxes by correcting for beam spillage, enhancing the precision of XPS analysis.
Implementation Method 1
XPS spectra are obtained by irradiating the substrate with a beam of X-rays, while simultaneously measuring the kinetic energy and number of electrons that escape from the top layers of the substrate
Data Source
AI summary
A system to characterize a film layer within a measurement box is disclosed. The system obtains a first mixing fraction corresponding to a first X-ray beam, the mixing fraction represents a fraction of the first X-ray beam inside a measurement box of a wafer sample, the measurement box represents a bore structure disposed over a substrate and having a film layer disposed inside the bore structure. The system obtains a contribution value for the measurement box corresponding to the first X-ray beam, the contribution value representing a species signal outside the measurement box that contributes to a same species signal inside the measurement box. The system obtains a first measurement detection signal corresponding to a measurement of the measurement box using the first X-ray beam. The system determines a measurement value of the film layer based on the first measurement detection signal, the contribution value, and the first mixing fraction.