Chemical bond modification in porous SiOCH films by H2 and H2/N2 plasmas investigated by <i>in situ</i> infrared reflection absorption spectroscopy

Yamamoto, Hiroshi; Asano, Kohei; Ishikawa, Kenji; Sekine, Makoto; Hayashi, Hisataka; Sakai, Itsuko; Ohiwa, Tokuhisa; Takeda, Keigo; Kondo, Hiroki; Hori, Masaru

doi:10.1063/1.3671547

Cited by 31 publications

(19 citation statements)

References 26 publications

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“…These plasma ashes are commonly utilized post plasma etching to remove photoresist and any polymer residues that may have formed on the surfaces of patterned structures during plasma etching. From several prior studies [63][64][65][66], it has been well established that such plasma ashes typically selectively remove terminal methyl groups from the chemical structure / matrix of low-k dielectrics. The degree to which terminal methyl groups are removed depends on both the oxidation potential and length of the plasma ash exposure as well as the amount of interconnected nano-porosity present in the low-k dielectric.…”

Section: To Allow a Better Visual Comparison Of The T-ftir Gatr Andmentioning

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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Section: To Allow a Better Visual Comparison Of The T-ftir Gatr Andmentioning

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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“…Numerous investigations of low-k a-SiOC:H materials have shown a propensity for these materials to lose terminal methyl (CH 3 ) groups during the plasma etching, ashing, and CMP steps utilized to fabricate inlaid Cu wiring. [66][67][68] The loss of such terminal organic groups in low-k a-SiOC:H dielectrics typically results in the formation of new chemical bonds and a more SiO 2 like composition. 69,70 These effects are most commonly observed as "sidewall damage" resulting from plasma etch and ashing processes that convert to SiO 2 the sidewalls of trenches etched into the low-k a-SiOC:H dielectric.…”

Section: Absorbance (Au)mentioning

confidence: 99%

Nanoscale Chemical-Mechanical Characterization of Nanoelectronic Low-kDielectric/Cu Interconnects

Lo¹,

Dazzi

Marcott³

et al. 2015

ECS J. Solid State Sci. Technol.

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Combined nanoscale chemical and mechanical property characterization has largely been limited by the inability to extend chemical structure identification techniques such as infrared (IR) absorption spectroscopy into the nanometer regime due to diffraction limitations. The recent development of atomic force microscope (AFM) based IR spectroscopy (AFM-IR) has now enabled infrared chemical spectroscopy with resolution well below the diffraction limit. However, the combination of AFM-IR with other AFM based techniques to achieve nanoscale chemical structure-mechanical property characterization has yet to be demonstrated. In this regard, we have combined AFM-IR chemical and contact resonance AFM (CR-AFM) mechanical measurements in the investigation of low dielectric constant (low-k) / Cu damascene structures fabricated using a 90 nm interconnect process technology. We show that the combined AFM-IR and CR-AFM results can be utilized to perform nanoscale chemical-mechanical characterization of both the nano-patterned metal and the low-k dielectric whose mechanical properties are sensitive to chemical modification by the interconnect fabrication process. The continued drive to seek and exploit new materials and phenomena at nanometer dimensions has increased the demand for metrologies capable of characterizing both chemical structure and physical properties at the nanoscale. The nanoelectronics industry in particular has identified metrologies capable of performing nanoscale structureproperty measurements on new materials and devices as an area of critical need in their industry technology roadmap.1,2 Such requirements for nanoscale physical property characterization have readily been met by the development of a range of scanned probe techniques capable of assessing the thermal, 3,4 mechanical, 5,6 and electrical 7,8 properties of materials at the nanoscale. 9 However, the development of nanoscale chemical structure metrologies has been hindered by the difficulty of scaling popular micron-scale techniques such as infrared (IR) absorption spectroscopy [10][11][12] into the nanometer regime due to diffraction limits defined by the Rayleigh equation.13,14 To overcome these limitations, a number of approaches combining optical spectroscopy with scanned probe microscopy (SPM) have been proposed and demonstrated. [13][14][15][16][17][18][19][20] Of these, the atomic force microscope (AFM) IR technique, which is based on photothermally induced resonance (PTIR), 21,22 has recently garnered significant interest due to a demonstrated spatial resolution of 25-100 nm, and a close correlation to micron-scale Fourier transform infrared (FTIR) spectroscopy. 13,14 This combination has resulted in the utilization of AFM-IR in a number of biological, 23-25 polymeric, 26-28 and semiconductor [29][30][31] applications. However, AFM-IR and related techniques have yet to be routinely combined with other AFM based techniques to achieve the ultimate goal of nanoscale structure-property characterization. In this regard, we provide a compelling...

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“…This dangling bond easily absorbs H or NH 2 species to form Si-H or Si-NH 2 bonds due to a lower reaction energy, which is thermodynamically favorable. [22][23][24][25] The Si-H and Si-NH 2 bonds are not stable in air and easily react with ambient air to form Si-OH, which is more hydrophobic and has a higher dielectric constant. As the portion of NH 3 in the plasma increases, the number of H and NH 2 active species increases accordingly.…”

Section: Resultsmentioning

confidence: 99%

Effect of NH3/N2 ratio in plasma treatment on porous low dielectric constant SiCOH materials

Huang

Chang

et al. 2014

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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This study investigates the effect of the NH 3 /N 2 ratio in plasma treatment on the physical and electrical properties as well as the reliability characteristics of porous low-k films. All of the plasma treatments resulted in the formation of a thin and modified layer on the surface of porous low-k films, and the properties of this modified layer were influenced by the NH 3 /N 2 ratio in the plasma. Experimental results indicated that pure N 2 gas plasma treatment formed an amide-like/ nitride-like layer on the surface, which apparently leads to a higher increase in the dielectric constant. Plasma treatment with a mixture of NH 3 /N 2 gas induced more moisture uptake on the surface of the low-k dielectric, degrading the electrical performance and reliability. Among all plasma treatment with NH 3 /N 2 mixed gas, that with pure NH 3 gas yielded low-k dielectrics with the worse electrical and reliability characteristics. V

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Chemical bond modification in porous SiOCH films by H2 and H2/N2 plasmas investigated by in situ infrared reflection absorption spectroscopy

Cited by 31 publications

References 26 publications

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

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

Nanoscale Chemical-Mechanical Characterization of Nanoelectronic Low-kDielectric/Cu Interconnects

Effect of NH3/N2 ratio in plasma treatment on porous low dielectric constant SiCOH materials

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