Backscattered Electron Counting for Thin Film Thickness Estimation
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Solution Overview
Problem
Conventional methods for measuring the thickness of thin films in semiconductor components face challenges such as difficulty in measuring on a small scale, evaluating signal strength, and inaccuracies in results, particularly for specific film materials.
Innovation Solution
A method using direct electron detection with a charged particle detector array to count backscattered electrons, determining statistical electron characteristics, and fitting these to a thickness function to estimate film thickness, independent of detector brightness and gain settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional backscattering methods are used for thickness determination, then measurement capability is provided, but measurement precision and reliability are reduced due to signal evaluation difficulties and material restrictions
Solution Approach 1:
The patent replaces conventional indirect detection methods with direct electron counting using a direct electron detector. This substitution of detection mechanism eliminates the need for complex signal processing and brightness/gain adjustments, directly counting backscattered electrons to achieve more precise and reliable thickness measurements across different film materials.
Solution Approach 2:
The patent changes the detection parameter from indirect signal intensity measurement to direct electron count measurement. By counting individual backscattered electrons rather than measuring analog signal strength, the method achieves improved measurement precision and eliminates the difficulties associated with signal evaluation in conventional methods.
2Reliability
If conventional backscattering methods are used, then thickness measurement is possible, but repeatability is reduced due to detector brightness and gain settings
Solution Approach 1:
The patent replaces the complex analog detection system with a direct electron counting system. This eliminates brightness and gain settings entirely, as the detector directly counts electrons rather than measuring analog signal intensities. The result is improved measurement repeatability and reduced device complexity regarding detector settings.
3Measurement precision
If conventional methods are used for thin film measurement, then general measurement capability is provided, but measurement precision deteriorates on small scales
Solution Approach 1:
The patent changes the detection parameter to direct electron counting, which provides superior precision for small scale measurements. By counting individual electrons rather than measuring analog signals, the method achieves accurate thickness measurements even for ultra-thin films where conventional methods struggle with signal strength and precision.
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
This approach provides accurate and repeatable thickness measurements by directly counting and measuring electron energies, overcoming the limitations of conventional methods and improving precision.
Implementation Method 1
obtaining backscattered electron data of the sample using a direct charged particle detector comprising an array of pixels and configured to count the number of backscattered electrons detected by each pixel of the array when an electron beam is incident upon the sample
Data Source
AI summary
A method comprises determining parameters of a thickness function for estimating a thickness of a sample. The thickness function defines a relationship between the thickness of the sample and a statistical electron characteristic. The method comprises obtaining backscattered electron data of the sample using a direct charged particle detector comprising an array of pixels and configured to count the number of backscattered electrons detected by each pixel of the array when an electron beam is incident upon the sample. Backscattered electron data sets can include the number of backscattered electrons detected by each pixel of the array when the electron beam is incident upon a respective region of the sample. The method further comprises determining, for each data set, a respective statistical electron characteristic, and then fitting the known thicknesses and the determined statistical electron characteristic to the thickness function to determine the parameters of the thickness function.