Effects of plasma and vacuum-ultraviolet exposure on the mechanical properties of low-k porous organosilicate glass

Guo, Xiangyu; Jakes, Joseph E.; Banna, S.; Nishi, Yoshio; Shohet, J. L.

doi:10.1063/1.4891501

Cited by 25 publications

(22 citation statements)

References 37 publications

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“…[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. This "sidewall damage" becomes readily apparent after dilute HF cleans where the SiO 2 damage layer is selectively etched away resulting in a widening of the formed trench and undercut of any overlying hard mask materials.…”

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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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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“…However, a significant low‐ k film sputtering should take place at these high ion energies. It is necessary to note that a possibility of low‐ k sputtering at floating potential was demonstrated by Lopaev et al recently and was remarked on also by Guo et al on the basis of XPS measurements.…”

Section: Introductionmentioning

confidence: 87%

“…However, it was observed experimentally that the densification of the uppermost surface layer for some OSG films can occur under ion irradiation, thus reducing or even preventing material damage …”

Section: Introductionmentioning

confidence: 99%

“…The effect of Ar ions on low‐ k film structure modification was studied both in plasma and in an ion beam experiment . Guo et al studied the separate effects of plasma and VUV radiation exposures on the surface properties of low‐ k porous OSG dielectric films. It was shown that the O–Si–O structure can be disordered by VUV radiation …”

Section: Introductionmentioning

confidence: 99%

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Pore sealing mechanism in OSG low‐k films under ion bombardment

Воронина

Sycheva

Lopaev

et al. 2019

Plasma Processes & Polymers

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Organosilicate glass (OSG) nanoporous films with a low dielectric constant (low-k) are used as interlayer-dielectric insulators for advanced interconnects of ultra-large-scale integration devices. Plasma treatment of these materials can lead to their degradation resulting in increasing k-value and reducing lifetime and reliability. However, for some OSG films, the densification of the uppermost surface layer and pore sealing was observed under ion irradiation. This paper presents the results of a combined experimental and modeling study of mechanisms of low-k film densification by ion bombardment depending on the film-pore size, ion type, and energy.The obtained results reveal that experimentally observed densification and pore sealing of uppermost layers of OSG films occur via collapse of near-surface pores under the impact of energetic ions. K E Y W O R D Slow-k dielectrics, molecular dynamics, nanoporous materials, plasma damage, pore sealing

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“…4 However, the reduced-k-value of interlayer dielectrics, typically produced with the introduction of nanoporosities, can seriously compromise the performance of an actual low-k/ Cu interconnect. [5][6][7] One critical challenge is electrical leakage at the interface between Cu and low-k dielectrics, particularly as electric fields approach 1 MV/cm or greater for <10-nm technology nodes. 8,9 Since interfacial barriers can play an important role in determining the charge transport characteristics and the potential electrical leakage mechanisms between materials, there is a critical need to understand the fundamental electronic band alignment between low-k interlayer dielectrics and Cu lines.…”

mentioning

confidence: 99%

Measurements of Schottky barrier at the low-k SiOC:H/Cu interface using vacuum ultraviolet photoemission spectroscopy

Guo

Pei

Zheng

et al. 2015

Applied Physics Letters

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The band alignment between copper interconnects and their low-k interlayer dielectrics is critical to understanding the fundamental mechanisms involved in electrical leakage in low-k/Cu interconnects. In this work, vacuum-ultraviolet (VUV) photoemission spectroscopy is utilized to determine the potential of the Schottky barrier present at low-k a-SiOC:H/Cu interfaces. By examining the photoemission spectra before and after VUV exposure of a low-k a-SiOC:H (k = 3.3) thin film fabricated by plasma-enhanced chemical-vapor deposition on a polished Cu substrate, it was found that photons with energies of 4.9 eV or greater can deplete accumulated charge in a-SiOC:H films, while VUV photons with energies of 4.7 eV or less, did not have this effect. These critical values were identified to relate the electric potential of the interface barrier between the a-SiOC:H and the Cu layers. Using this method, the Schottky barrier at the low-k a-SiOC:H (k = 3.3)/Cu interface was determined to be 4.8 ± 0.1 eV.

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Effects of plasma and vacuum-ultraviolet exposure on the mechanical properties of low-k porous organosilicate glass

Cited by 25 publications

References 37 publications

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

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

Pore sealing mechanism in OSG low‐k films under ion bombardment

Measurements of Schottky barrier at the low-k SiOC:H/Cu interface using vacuum ultraviolet photoemission spectroscopy

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