Improved characterization of Fourier transform infrared spectra analysis for post-etched ultra-low-κ SiOCH dielectric using chemometric methods

Oszinda, Thomas; Beyer, V.; Schaller, Μ.; Fischer, Daniel; Bartsch, Christin; Schulz, Stefan E.

doi:10.1116/1.3043466

Cited by 8 publications

(12 citation statements)

References 17 publications

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“…where A (k) = 0.434αd 3 is the corrected spectrum calculated from (9), and the sum extends over the frequencies k that are away from any absorption peaks so that one can expect that A (k) is zero at those wavelengths. N is the number of data points in the sum.…”

Section: Fully Coherent Correction Methodsmentioning

confidence: 99%

“…The iterative approach used in Ref. 16 allowed all three parameters to be extracted from (9). The film thickness d 2 and refractive index n at a particular wavelength are usually determined independently by an ellipsometric technique, so those values can serve as an initial guess.…”

Section: Fully Coherent Correction Methodsmentioning

confidence: 99%

“…[4][5][6] For low-k materials, T-FTIR spectroscopy has shown great utility for qualitatively understanding structure-property relationships and fine tuning of material properties to meet the industry's need. [7][8][9][10][11][12][13][14] However, several problems are encountered when attempting to quantitatively analyze T-FTIR spectra of these and other types of thin films on thick substrates. These challenges are primarily due to the presence of strong interference fringes in the spectra produced by multiple reflections within the substrate and thin film.…”

mentioning

confidence: 99%

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Analysis of Low-k Dielectric Thin Films on Thick Substrates by Transmission FTIR Spectroscopy

Milošević¹,

King²

2014

ECS J. Solid State Sci. Technol.

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Transmission Fourier-transform infrared (T-FTIR) spectra of thin films on thick substrates are characterized by strong interference fringes that hamper quantitative analysis of the observed thin film absorption bands. In this article, we review and present methods for removing these fringes to extract the pure thin film absorption coefficient from the experimental T-FTIR spectra. To illustrate the benefits of a recently developed method for removing such fringes, we analyze T-FTIR spectra for a series of a-SiO2 and a-SiOC:H thin films typically utilized in nano-electronic interconnect structures as low permittivity (i.e. low-k) interlayer dielectrics. The sources and magnitude of the errors present in analysis of both the uncorrected and corrected experimental T-FTIR spectra are compared. We demonstrate that conventional analysis of the uncorrected low-k a-SiOC:H T-FTIR spectra can lead to substantial quantitative errors that are dramatically reduced using the described method for appropriately removing the experimental thin film fringes.

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Section: Fully Coherent Correction Methodsmentioning

confidence: 99%

Section: Fully Coherent Correction Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Analysis of Low-k Dielectric Thin Films on Thick Substrates by Transmission FTIR Spectroscopy

Milošević¹,

King²

2014

ECS J. Solid State Sci. Technol.

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“…Fortunately, the chemical structure / bonding of low-k dielectrics is ideally suited for characterization by IR spectroscopy due to the strong IR activity of both the organic component (through various C-H stretching and deformation bands) and the inorganic component (through the Si-O and Si-H stretching bands) [42]. Numerous FTIR, GATR and multiple internal reflection IR (MIRIR) spectroscopy investigations of the chemical modification of low-k dielectrics by various nanofabrication processes have been performed on blanket films [43][44][45][46][47][48][49] and in some cases large periodic arrays of m-nm wide patterned features [26,[50][51][52]. These studies have established general trends and correlations between process chemistries and the low-k dielectric chemical bond structure to the susceptibility of process induced chemical modification.…”

Section: Introductionmentioning

confidence: 99%

Nanoscale chemical structure variations in nano-patterned and nano-porous low-k dielectrics: A comparative photothermal induced resonance and infrared spectroscopy investigation

Kjoller

Myers

et al. 2016

Vibrational Spectroscopy

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The recent development of the photothermal induced resonance (PTIR) technique has enabled atomic force microscope based infrared (AFM-IR) spectroscopy and imaging to be achieved at the nanometer scale. However, a direct correspondance between PTIR/AFM-IR and more traditional Fourier transform IR (FTIR) spectroscopy has been prohibited for nanometer scale features due to Rayleigh diffraction constraints that limit the latter to few micron spatial resolution. In this regard, we have overcome this challenge by fabricating 1 cm 2 arrays of 90 nm wide fins in a nano-porous low dielectric constant (i.e. low-k) amorphous hybrid inorganicorganic silicate material using standard nano-electronic fabrication techniques. With these structures, we demonstrate both a general correspondance between AFM-IR, FTIR, and Germanium attenuated total reflection (GATR) IR spectroscopy, as well as differences in the sensitivities that these techniques exhibit to the nanoscale variations in chemical structure induced in the low-k dielectric by the nanopatterning method. To further illustrate the sensitivity of AFM-IR to changes in chemical structure with nanometer resolution, the nanopatterned low-k

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“…[39][40][41][42][43] For the low-k a-SiC:H films investigated in this study, prior investigations 14,15 have indicated the presence of significant amounts of IR inactive Si-Si and C-C bonds. In the following, it is demonstrated that the PLS analysis can actually account for elements present with some IR inactive chemical bonds.…”

Section: Pls Elemental Concentration Calculationsmentioning

confidence: 96%

Complete Elemental Analysis of Low-ka-SiC:H Thin Films by Transmission FTIR Spectroscopy

Milošević¹,

King

2014

ECS J. Solid State Sci. Technol.

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Fourier transform infrared (FTIR) spectroscopy is a popular technique for qualitatively investigating the chemical bonding of low dielectric constant (low-k) materials utilized in nanoelectronic Cu interconnects. However, quantitative FTIR analysis of low-k materials with widely varying stoichiometry has proven challenging due to numerous optical interference effects, variations in IR absorption strength with optical constants, and a negligible IR activity for homopolar bonds. In this paper, these challenges are overcome to demonstrate full elemental composition analysis by applying multivariate partial least squares (PLS) modeling to the true IR absorbance spectra obtained using previously described methods for eliminating optical interference effects from thin film FTIR spectra. To demonstrate the validity of this approach, transmission FTIR spectra were collected from a series of low-k a-SiC:H thin films with hydrogen content ranging from 25-60%. The elemental concentrations determined from PLS analysis of the corrected low-k a-SiC:H FTIR spectra were found to be in agreement to within ±5% of results obtained from independent nuclear reaction analysis and Rutherford backscattering measurements. These results demonstrate a clear path for establishing transmission FTIR as a quantitative metrology for full compositional analysis (elemental and chemical bond) for a wide range of thin film materials.

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Improved characterization of Fourier transform infrared spectra analysis for post-etched ultra-low-κ SiOCH dielectric using chemometric methods

Abstract: Ultralow k using a plasma enhanced chemical vapor deposition porogen approach: Matrix structure and porogen loading influences

Cited by 8 publications

References 17 publications

Analysis of Low-k Dielectric Thin Films on Thick Substrates by Transmission FTIR Spectroscopy

Analysis of Low-k Dielectric Thin Films on Thick Substrates by Transmission FTIR Spectroscopy

Nanoscale chemical structure variations in nano-patterned and nano-porous low-k dielectrics: A comparative photothermal induced resonance and infrared spectroscopy investigation

Complete Elemental Analysis of Low-ka-SiC:H Thin Films by Transmission FTIR Spectroscopy

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