Terahertz Wave Multilayer Specimen Thickness Measurement
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Solution Overview
Problem
Current methods struggle to accurately measure the thickness of multilayered specimens without damaging them, especially when multiple thin films are involved, as existing nondestructive inspection techniques are inadequate for precise thickness measurement of each layer.
Innovation Solution
A terahertz wave-based method that emits and receives terahertz waves to calculate the thickness of each layer by measuring reflection and transmission times, utilizing the refractive index of each layer to determine the thickness, allowing for non-contact and nondestructive inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional nondestructive inspection techniques are used, then the specimen is not damaged, but the measurement precision of each layer thickness is insufficient
Solution Approach 1:
The patent segments the measurement process into multiple frequency components, emitting terahertz waves at different frequencies (e.g., first frequency and second frequency) to separately measure different layers. By dividing the measurement into frequency segments, the system achieves precise individual layer thickness measurement while maintaining nondestructive inspection capability.
Solution Approach 2:
The patent introduces frequency as an additional dimension for measurement differentiation. Instead of using a single measurement approach, it utilizes multiple frequency dimensions of terahertz waves to distinguish and measure each layer's thickness independently, thereby achieving both high precision and nondestructive inspection.
2Measurement precision
If multiple thin films are measured separately, then individual layer thickness can be obtained, but the specimen must be separated into respective thin films
Solution Approach 1:
The patent applies segmentation to the electromagnetic spectrum by using different frequency bands to probe different layers. The first terahertz wave at a first frequency measures the first thin film, while the second terahertz wave at a second frequency measures the second thin film, allowing individual layer measurement without physical separation.
Solution Approach 2:
The patent uses terahertz waves as an intermediary medium to penetrate and measure multiple thin films simultaneously. The electromagnetic waves act as a non-contact mediator that can distinguish between different layers based on their frequency-dependent interaction with the material, eliminating the need for physical specimen separation.
3Ease of operation
If external light is not blocked, then the measurement process is simplified, but measurement precision may be affected
Solution Approach 1:
The patent changes the parameter of electromagnetic wave frequency to terahertz range, which has different interaction characteristics with materials compared to visible light. This frequency parameter change allows the measurement to proceed without external light blocking, as the terahertz waves can penetrate and measure the thin films independently of ambient visible light conditions.
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 and efficient measurement of each layer's thickness in multilayered specimens, even when the refractive index is unknown, providing high availability and increased precision without the need for additional processes to block external light.
Implementation Method 1
a terahertz wave has features such as an excellent transmittance with respect to a nonconductive material except metals
Implementation Method 2
receiving a first reflected terahertz wave, emitting a second terahertz wave, receiving a second reflected terahertz wave
Data Source
AI summary
A method for measuring the thickness of a specimen, according to an embodiment, can measure the thickness of a specimen having multiple layers in a contactless and non-destructive manner. In addition, when the refractive indexes of materials forming the respective layers are already known, the thicknesses of the respective layers can be integrally measured through differences in reflection times of terahertz waves with respect to the respective layers of the specimen, thereby measuring the thickness of the specimen, such that the time taken for measuring the thickness of the specimen can be reduced. Furthermore, when the refractive indexes of the materials forming the respective layers are not known, the refractive indexes of the respective layers can be measured through differences in transmission times and reflection times of terahertz waves with respect to the respective layers of the specimen, and at the same time, the thicknesses of the respective layers can be measured through differences in transmission times or reflection times of terahertz waves with respect to the respective layers of the specimen, so that the thickness of various specimens can be measured. As such, the present invention has a wide range of applications.