Impact of Barrier Metal Sputtering on Physical and Chemical Damages in Low-k SiOCH Films with Various Hydrocarbon Content

Inoue, N.; Furutake, N.; Ito, Fuminori; Yamamoto, Hironori; Takeuchi, T.; Hayashi, Y.

doi:10.1143/jjap.47.2468

Cited by 24 publications

(12 citation statements)

References 13 publications

(13 reference statements)

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“…N. Inoue et al also observed the k value increase from original 2.6 to 3.0 after adding Ta sputtering process with low DC bias. 21 These results indicate that introducing an ultrathin Al 2 O 3 film to pretreat the low k surface does not have a significant impact on the effective k value of the resulting capacitor structure.…”

mentioning

confidence: 81%

Improved Thermal Stability and Electrical Performance by Using PEALD Ultrathin Al2O3 Film with Ta as Cu Diffusion Barrier on Low k Dielectrics

Xie

Chen

et al. 2012

ECS Solid State Letters

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Ultrathin Al 2 O 3 films (1.3 nm or 2.5 nm) were deposited by plasma enhanced atomic layer deposition (PEALD) onto the low k (k = 2.5) material. By ALD deposition of an ultrathin Al 2 O 3 film onto the low k surface, the thermal stability and electrical performance for the Cu/Ta/Al 2 O 3 /low k/Si system were significantly improved in comparison to those with even thicker Ta and ALD Ru/TaN layers as diffusion barrier. The effective k value of the system was not degraded by adding the ultrathin Al 2 O 3 layer.With the continuing scaling down of the line pitch in very large scale integrated circuits, ultrathin Cu diffusion barriers are necessary to mitigate the increase in the effective resistivity of the Cu interconnects due to grain boundary scattering and interface scattering. Conformal deposition of thin films in high aspect ratio trenches using traditional physical vapor deposition (PVD) technique is becoming difficult. 1 Atomic layer deposition (ALD) is considered as a promising method to get excellent conformal films with thickness control at atomic level owing to its intrinsic self-limited growth feature. 2 ALD grown metals or nitrides, such as Ru 3,4 and TaN films, 5,6 have been widely studied as Cu diffusion barriers or adhesion layers. ALD grown oxides, such as TiO 2 , 7,8 Ta 2 O 5 7,9,10 and Al 2 O 3 11,12 have also been reported as Cu diffusion barriers due to their excellent uniformity and thermal stability. P. Alen 7 and Qi Xie 8 reported the excellent thermal stability of ALD TiO 2 . P. Majumder et al. reported that the ultrathin Al 2 O 3 layer deposited by thermal ALD as diffusion barrier between Cu and Si substrate had excellent thermal stability. 11,12 However, these oxide layers were all directly deposited onto Si and the very primary properties of diffusion barriers to Cu were measured. A systematic study of ALD oxide films as Cu diffusion barrier onto a low k dielectric has been rarely reported. 7-12 In this work, ultrathin Al 2 O 3 films were deposited by PEALD together with a Ta adhesion layer, and their properties as a Cu diffusion barrier on a low k dielectric (k = 2.5) were studied.Low k films (Novellus CORAL, k = 2.5) with a thickness of 220 nm were deposited on the 12" p-type Si wafers. The wafers were cut into small pieces and then were cleaned in an ultrasonic cleaner with 2-propanol solution before loading into the loadlock chamber. After in-situ annealing at 250 • C for 20 minutes in the high vacuum ALD chamber, 11 or 21 cycles (∼1.2 Å/cycle) Al 2 O 3 films were grown by PEALD using trimethylaluminium (TMA) and remote O 2 plasma (200W) as precursors. The growth temperature was 250 • C. After deposition, samples were taken out and transferred into a PVD chamber. The details of the ALD growth can be seen elsewhere. 7 Then the Cu(50 nm)/Ta (5 nm) film stacks were deposited by DC magnetron sputtering. The thin Ta film was used as a glue layer to promote adhesion between the Cu and Al 2 O 3 barrier layers. To form the patterned metal-insulatorsemiconductor (MIS) structures, a shadow mask...

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mentioning

confidence: 81%

Improved Thermal Stability and Electrical Performance by Using PEALD Ultrathin Al2O3 Film with Ta as Cu Diffusion Barrier on Low k Dielectrics

Xie

Chen

et al. 2012

ECS Solid State Letters

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“…This process flow specifically consisted of plasma cleaning, physical vapor deposition (PVD), chemical mechanical planarization (CMP) and wet chemical cleaning steps that have all shown the potential to remove terminal organic groups from the matrix of nanoporous organosilicate dielectrics in a similar fashion as observed previously by the pattern transfer process [31,52–53]. This is clearly shown in Fig.…”

Section: Resultsmentioning

confidence: 83%

“…To further strengthen the observed chemical structure–mechanical property relationship, the silylated nanoporous organosilicate fins were exposed to additional plasma and wet chemical processes to fill the spaces between the fins with Cu as in a typical state-of-the-art metal interconnect structure. This process flow specifically consisted of plasma cleaning, physical vapor deposition (PVD), chemical mechanical planarization (CMP) and wet chemical cleaning steps that have all shown the potential to remove terminal organic groups from the matrix of nanoporous organosilicate dielectrics in a similar fashion as observed previously by the pattern transfer process [ 31 , 52 – 53 ]. This is clearly shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Relationships between chemical structure, mechanical properties and materials processing in nanopatterned organosilicate fins

Stan

Gates

et al. 2017

Beilstein J. Nanotechnol.

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The exploitation of nanoscale size effects to create new nanostructured materials necessitates the development of an understanding of relationships between molecular structure, physical properties and material processing at the nanoscale. Numerous metrologies capable of thermal, mechanical, and electrical characterization at the nanoscale have been demonstrated over the past two decades. However, the ability to perform nanoscale molecular/chemical structure characterization has only been recently demonstrated with the advent of atomic-force-microscopy-based infrared spectroscopy (AFM-IR) and related techniques. Therefore, we have combined measurements of chemical structures with AFM-IR and of mechanical properties with contact resonance AFM (CR-AFM) to investigate the fabrication of 20-500 nm wide fin structures in a nanoporous organosilicate material. We show that by combining these two techniques, one can clearly observe variations of chemical structure and mechanical properties that correlate with the fabrication process and the feature size of the organosilicate fins. Specifically, we have observed an inverse correlation between the concentration of terminal organic groups and the stiffness of nanopatterned organosilicate fins. The selective removal of the organic component during etching results in a stiffness increase and reinsertion via chemical silylation results in a stiffness decrease. Examination of this effect as a function of fin width indicates that the loss of terminal organic groups and stiffness increase occur primarily at the exposed surfaces of the fins over a length scale of 10-20 nm. While the observed structure-property relationships are specific to organosilicates, we believe the combined demonstration of AFM-IR with CR-AFM should pave the way for a similar nanoscale characterization of other materials where the understanding of such relationships is essential.

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“…1. However, the near continuous implementation of new lowk dielectrics with each new technology was not without significant and well documented challenges [107][108][109][110][111] that severely impacted the development of the associated metallization, [112][113][114] patterning, [115][116][117][118][119] and packaging [120][121][122][123] processes needed to fabricate a high yielding metal interconnect. By the mid 2010's, the challenges of implementing new low-k SiOCH ILDs with k ≤ 2.3 had reached a breaking point relative to overall technology development goals for numerous reasons.…”

Section: The End Of Permittivity Scaling?mentioning

confidence: 99%

Review—Beyond the Highs and Lows: A Perspective on the Future of Dielectrics Research for Nanoelectronic Devices

Jenkins

Austin

Conley

et al. 2019

ECS J. Solid State Sci. Technol.

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High-dielectric constant (high-k) gate oxides and low-dielectric constant (low-k) interlayer dielectrics (ILD) have dominated the nanoelectronic materials research scene over the past two decades, but they have recently reached a state of maturity and perhaps the limits of their scaling. Based on this, there is a need for a systematic review summarizing not only the historic research and achievements on high-k and low-k dielectrics, but also emerging device applications as well as an outlook of future challenges. We begin by first reviewing the factors that drove the emergence of low-k and high-k materials in nanoelectronics as ILD and gate dielectric materials, respectively, and the challenges and limits these materials ultimately approached in terms of permittivity scaling. We then illustrate that gate dielectric and ILD applications represent just a small fraction of the numerous dielectrics utilized in present day nanoelectronic products where permittivity scaling is now being increasingly demanded for materials such as dielectric spacers, trench isolation, and etch stopping layers. We conclude by examining the numerous new applications for dielectric materials that are emerging as the semiconductor industry transitions to novel patterning schemes, prepares for life post CMOS scaling, and explores ways to natively embed device functionality in the metal interconnect. For the former, we specifically examine the “colorful” requirements for the various enabling dielectric hardmask and spacer materials utilized in pitch division-multi-pattern processes and then discuss the role that selective area deposition of dielectrics and metals could play in reducing the complexity of such patterning processes. For the latter, we review the use of both high-k and low-k dielectrics in various metal-insulator-metal (MIM) structures as Fermi level de-pinning layers, tunnel diodes, and back-end-of-line (BEOL) compatible capacitive and resistive switching random access memory (ReRAM) elements. We further examine how dielectrics can hinder or aid new forms of computing such as quantum and neuromorphic in reaching their full potential. In conclusion, we find that while the field of dielectrics has a long history, it remains vibrant with numerous exciting new and old research vectors awaiting further exploration.

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Impact of Barrier Metal Sputtering on Physical and Chemical Damages in Low-k SiOCH Films with Various Hydrocarbon Content

Cited by 24 publications

References 13 publications

Improved Thermal Stability and Electrical Performance by Using PEALD Ultrathin Al2O3 Film with Ta as Cu Diffusion Barrier on Low k Dielectrics

Improved Thermal Stability and Electrical Performance by Using PEALD Ultrathin Al2O3 Film with Ta as Cu Diffusion Barrier on Low k Dielectrics

Relationships between chemical structure, mechanical properties and materials processing in nanopatterned organosilicate fins

Review—Beyond the Highs and Lows: A Perspective on the Future of Dielectrics Research for Nanoelectronic Devices

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