Thin Film Composition Analysis Below Optical Measurement Limits
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Solution Overview
Problem
Existing thin film analysis methods struggle to accurately measure and monitor the thickness of thin films with thicknesses equal to or less than the measurement limit of conventional devices, leading to issues such as increased production costs and degraded device performance due to suboptimal film formation, and difficulties in detecting and correcting defects.
Innovation Solution
A method and device that utilize a combination of optical constant measurement and mass spectrometry techniques to derive linear relation equations, allowing for the calculation of material composition ratios and layer thicknesses in thin films, even when individual layers are below the measurement limit, by using comparative samples with varying material amounts and measuring devices that analyze changes in polarization state and signal intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a film is formed to be thicker than the optimized thickness to avoid the measurement limit, then the thin film can be monitored by conventional devices, but production costs increase due to material consumption and device performance degrades
Solution Approach 1:
The patent divides the thin film into multiple layers (first layer with first material, second layer with second and third materials) and uses comparative samples with varying amounts of the second material. This segmentation allows the system to measure optical constants for each layer and derive linear relation equations to calculate the thickness of individual layers, enabling precise measurement of thin films below the conventional measurement limit without increasing overall film thickness
Solution Approach 2:
The patent introduces comparative samples as intermediaries that contain the same first and third materials but varying amounts of the second material. These comparative samples serve as reference standards to establish linear relations between optical constants and material amounts, which then enable the calculation of the main sample's composition and thickness without requiring the film to exceed measurement device limits
2Reliability
If a film is formed equal to or less than the measurement limit to optimize device performance, then device miniaturization and performance are improved, but it becomes difficult to detect and correct defects through monitoring
Solution Approach 1:
The patent uses comparative samples as intermediary reference standards that enable the measurement system to indirectly determine the thickness and composition of the main thin film sample. By measuring optical constants of both the main sample and comparative samples, and deriving linear relation equations, the system can calculate precise thickness values for films that are too thin for direct measurement, thereby enabling defect detection while maintaining optimized film thickness
Solution Approach 2:
The patent changes the measurement approach from direct thickness measurement to indirect measurement through optical constant analysis. By measuring optical constants (which can be measured for very thin films) and using derived linear relation equations, the system transforms the measurement parameter from thickness (which has a lower measurement limit) to optical constants (which can be measured for thinner films), enabling monitoring of ultra-thin films
3Ease of operation
If conventional optical measurement methods are used for thin films, then the measurement process is simple, but it is difficult to apply the method to thin films with thickness equal to or less than the measurement limit
Solution Approach 1:
The patent enhances the universality of optical measurement by extending its applicability from conventional thickness ranges to ultra-thin film ranges. The method maintains the simplicity of optical measurement while adding the capability to handle films below the conventional measurement limit through the use of comparative samples and linear relation equations, making the measurement system versatile across a broader thickness range
Solution Approach 2:
The patent introduces comparative samples as intermediaries that bridge the gap between conventional optical measurement capabilities and ultra-thin film measurement requirements. These comparative samples enable the simple optical measurement process to be applied to thin films that would otherwise be immeasurable, maintaining operational simplicity while expanding adaptability
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 precise measurement and optimization of thin film thickness, ensuring device reliability, reducing production costs, and facilitating defect detection and correction, while overcoming the limitations of conventional measurement techniques.
Implementation Method 1
the first measurement device may be a device using a change in the polarization state of a light incident on the main sample or the comparison samples and then reflected from the main sample or the comparison samples
Implementation Method 2
Such a method may be based on the principle of confirming the type of a material and the amount thereof by analyzing a light emitted when a sample material is excited by a light or particles incident on sample and then returned to a normal state
Data Source
AI summary
A method for analyzing a thin film includes: preparing a main sample and a plurality of comparative samples, each of which includes a first layer composed of a first material and a second layer composed of a second material and a third material, the first layer and the second layer being stacked, where each of the plurality of comparative samples has a different amount of the second material from the main sample; measuring optical constants of the main sample and the comparative samples; deriving a linear relation equation between each of the optical constants of the main sample and the comparative samples and the material amount of the second material of a corresponding one of the main sample and the comparative samples; and calculating a material composition ratio of the main sample based on the material amount of the second material of the main sample and the linear relation equation.