AFM-IR Sample with High CTE Surface Film
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Solution Overview
Problem
Atomic force microscopy-based infrared spectroscopy (AFM-IR) faces challenges in achieving high measurement sensitivity due to the low coefficient of thermal expansion of inorganic materials used in semiconductor devices, which limits the detection of infrared absorption spectra.
Innovation Solution
A sample configuration is developed with a substrate, a measurement portion, and a surface film having a higher coefficient of thermal expansion than the measurement portion, where the surface film is designed to absorb less infrared light, enhancing the thermal expansion detection and thus improving sensitivity. The surface film is preferably made of materials like epoxy resin, which has a lower absorption intensity than the measurement portion, allowing for increased displacement detection by the cantilever.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sample made of inorganic materials (such as semiconductor devices) is used for AFM-IR measurement, then the measurement can be performed on semiconductor devices, but the measurement sensitivity is low due to the low coefficient of thermal expansion of inorganic materials
Solution Approach 1:
The patent applies composite materials by combining an inorganic measurement portion (semiconductor device) with an organic coating film (epoxy resin or polymer). The coating film has a higher coefficient of thermal expansion than the inorganic measurement portion, creating a composite structure that amplifies thermal expansion effects. This allows AFM-IR measurement of inorganic materials while achieving sufficient measurement sensitivity through the organic component's enhanced thermal response.
2Measurement precision
If a surface film with high infrared absorption is used, then the sample structure can be protected, but the measurement sensitivity is reduced due to interference with infrared light detection
Solution Approach 1:
The patent applies local quality by creating a coating film with spatially varying properties: it has low infrared absorption in the measurement wavelength range to allow infrared light transmission, while providing sufficient mechanical protection. The coating film's material composition and thickness are optimized locally to balance protection and measurement requirements, ensuring that the film protects the sample structure without interfering with infrared absorption detection of the underlying measurement portion.
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 configuration enhances the measurement sensitivity of infrared absorption spectra by increasing the thermal expansion of the surface film, leading to greater cantilever displacement and improved detection of absorption intensities, even with materials of low thermal expansion.
Implementation Method 1
a measurement portion (23) provided on the substrate (21)... having a first light absorption intensity when a light of a first wavelength is irradiated thereon
Implementation Method 2
a first film (24) provided on the measurement portion (23)... having a higher coefficient of thermal expansion than the measurement portion (23)
Implementation Method 3
a first film (24) provided on the measurement portion (23)... having a higher coefficient of thermal expansion than the measurement portion (23)
Data Source
AI summary
A sample for atomic force microscopy-based infrared spectroscopy includes a substrate, a measurement portion provided on the substrate and having a first light absorption intensity when a light of a first wavelength is irradiated thereon, and a first film provided on the measurement portion and having a higher coefficient of thermal expansion than the measurement portion and a second light absorption intensity, which is less than the first light absorption intensity, when the light of the first wavelength is irradiated thereon.