Non-destructive Depth Profiling of Thin Film Elements
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Solution Overview
Problem
Conventional characterization techniques for thin films, such as SIMS, XPS, and AES, are invasive and unable to non-destructively measure material properties as a function of depth, making it difficult to analyze ultra-thin films like gate oxide layers in semiconductor devices, which require improved sensitivity and speed for production processes.
Innovation Solution
A non-destructive method using photoelectron spectroscopy to detect the depth distribution and centroid of elements in thin films, involving background subtraction, intrinsic spectrum extraction, and parameterization of depth distribution profiles, allowing for accurate prediction of electrical properties and process control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional characterization techniques (SIMS, XPS, AES) are used for depth profiling, then material properties as a function of depth can be measured, but the sample is destroyed in the process
Solution Approach 1:
The patent replaces the mechanical ion beam sputtering system with a photoelectron spectroscopy system that uses photons to excite electrons. This substitution eliminates the destructive mechanical removal of material while maintaining the ability to obtain depth distribution information through non-destructive electronic excitation and detection of photoelectrons from different depths
Solution Approach 2:
The patent changes the fundamental measurement parameter from ion beam energy (invasive) to photoelectron kinetic energy (non-invasive). By measuring the energy distribution of photoelectrons emitted from different depths and applying appropriate modeling, the system extracts depth profile information without altering the sample's physical state or composition
2Measurement precision
If ion beam sputtering is used for depth profiling, then depth distribution information can be obtained, but the process is time-consuming and unsuitable for production
Solution Approach 1:
The patent enables continuous measurement of photoelectrons from the sample surface without intermittent sputtering steps. The photoelectron spectroscopy system can continuously collect data from different depth regions by varying the photon energy or detection parameters, eliminating the time-consuming stepwise sputtering process and enabling faster analysis suitable for production environments
Solution Approach 2:
The patent uses computational modeling and simulation to predict depth distribution profiles from photoelectron spectra in advance. By pre-establishing the relationship between photoelectron energy distributions and depth profiles through modeling, the system can rapidly interpret experimental data without requiring time-consuming iterative measurements or extensive post-processing
3Quantity of substance
If conventional techniques are used for ultra-thin films, then surface composition can be analyzed, but depth profiling capability is lost
Solution Approach 1:
The patent transitions from two-dimensional surface composition analysis to three-dimensional depth-resolved analysis by incorporating the depth dimension through photoelectron inelastic mean free path considerations. By analyzing the energy distribution of photoelectrons and accounting for their attenuation through overlying layers, the system simultaneously provides surface composition and depth distribution information for ultra-thin films
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 determination of depth distribution and centroid of elements in thin films, improving the correlation between dose and electrical parameters, and enhancing the prediction of EOT and leakage current, thus facilitating better process control and device performance.
Implementation Method 1
A non-destructive method using photoelectron spectroscopy to detect the depth distribution and centroid of elements in thin films
Data Source
AI summary
A method to determine a distribution profile of an element in a film. The method comprises exciting an electron energy of an element deposited in a first film, obtaining a first spectrum associating with the electron energy, and removing a background spectrum from the first spectrum. Removing the background value generates a processed spectrum. The method further includes matching the processed spectrum to a simulated spectrum with a known simulated distribution profile for the element in a film comparable to the first film. A distribution profile is obtained for the element in the first film based on the matching of the processed spectrum to a simulated spectrum selected from the set of simulated spectra.