Non-destructive Depth Profile Analysis via ARXPS and Entropy Constraints
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Solution Overview
Problem
Current methods for evaluating the depth profile of semiconductor devices are either destructive, require complex pretreatment, or rely on inaccurate initial profiles, making them unsuitable for manufacturing applications.
Innovation Solution
A data analysis device and method that analyzes depth profiles by minimizing the sum of square deviations between theoretical and measured response signals, using a multilayer model with a maximum smoothness condition to ensure smooth concentration changes across layers, allowing for non-destructive evaluation without initial profile accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If ion sputtering is performed to evaluate deeper regions, then the information depth is improved, but the sample surface is damaged
Solution Approach 1:
Instead of using ion sputtering to physically remove material layers to achieve depth profiling, the patent inverts the approach by using angle-resolved photoelectron spectroscopy (ARXPS) to probe different depths optically. By varying the photoelectron emission angle, deeper regions are accessed without physical damage to the sample surface.
Solution Approach 2:
The patent replaces the mechanical ion sputtering process with a photoelectric measurement system. Instead of using ion beams to physically erode layers, X-rays or UV light are used to excite photoelectrons from different depths, achieving depth profiling through optical means rather than mechanical removal.
2Measurement precision
If STEM-EDX analysis is performed to achieve atomic layer resolution, then the measurement precision is improved, but the sample requires complicated pretreatment
Solution Approach 1:
The patent replaces the mechanical electron beam-based STEM-EDX system with a photoelectron spectroscopy system. This substitution eliminates the need for complex sample thinning and preparation, as ARXPS can analyze the top several nanometers of the sample surface in its native state without requiring atomic-layer thinning.
Solution Approach 2:
The patent extracts only the necessary information (chemical bonding state and depth profile) through photoelectron spectroscopy, eliminating the need for the complex sample preparation required by STEM-EDX. The method takes out the essential analytical capability while removing the cumbersome pretreatment requirements.
3Object-affected harmful factors
If MEM is applied to ARXPS data to evaluate depth profile, then the non-destructive evaluation is achieved, but the initial profile accuracy is required
Solution Approach 1:
The patent changes the analytical parameters by applying maximum entropy method (MEM) constraints to the ARXPS data analysis. By introducing entropy maximization as an additional constraint parameter, the system can retrieve depth profiles without requiring accurate initial profiles, as the entropy constraint guides the solution toward the most probable distribution.
Solution Approach 2:
The patent implements a feedback mechanism in the data analysis where the retrieved depth profile is continuously refined by comparing theoretical spectra with measured data and adjusting the profile to maximize entropy. This iterative feedback process eliminates the need for accurate initial profiles by using the measurement data itself to guide the solution.
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 accurate and non-destructive evaluation of depth profiles in semiconductor devices, eliminating the need for complex pretreatment and initial profile accuracy, thus improving analysis reliability and efficiency.
Implementation Method 1
analyzes the depth profile of the sample by minimizing a sum of square deviations between a theoretical value of the response signal and the measured value of the response signal
Implementation Method 2
calculates a relative concentration so as to satisfy a maximum smoothness condition that the relative concentration of chemical species of the sample smoothly changes in the plurality of layers
Implementation Method 3
a response signal generated from the sample by incidence of a probe
Data Source
AI summary
A data analysis device includes an input unit that receives a measured value of an optoelectronic signal from a photoelectron spectroscopic device measuring the optoelectronic signal generated from a sample by photoelectron spectroscopy and an analysis unit that analyzes the depth profile of the sample by minimizing a sum of square deviations between a theoretical value of the optoelectronic signal and the measured value of the optoelectronic signal using the theoretical value of the optoelectronic signal when the sample is modeled into a multilayer body including a plurality of layers. The analysis unit calculates a relative concentration so as to satisfy a maximum smoothness condition that the relative concentration of the chemical species of the sample smoothly changes in the plurality of layers of the multilayer body in minimizing the sum of square deviations.