Boron and high-<i>k</i> dielectrics: Possible fourth etch stop colors for multipattern optical lithography processing

Dhungana, Shailesh; Nguyen, Thuong D.; Nordell, Bradley J.; Caruso, Anthony N.; Paquette, Michelle M.; Chollon, Georges; Lanford, W. A.; Scharfenberger, Kris; Jacob, Danya; King, Sean W.

doi:10.1116/1.4974920

Cited by 9 publications

(8 citation statements)

References 55 publications

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“…8 For this reason, HF was included in the X−F structures. As mentioned previously, Dhungana et al 13 identified CH 3 F and CF 4 chemistries as uniquely poised for high etch rates for Al 2 O 3 and thus merits investigation here too. To complete the reaction scheme (eq 1) the calculations were also carried out to OH − , H 2 O, CH 3 OH, and CF 3 OH structures as reaction products, respectively.…”

Section: Acs Applied Materials and Interfacesmentioning

confidence: 76%

“…Thus, the wet and dry (plasma) chemistry required to selectively remove alumina (i.e., etching) has led to the identification of key chemical interactions that also have importance to energetic material applications. For example, Dhungana et al 13 specifically investigated etching of Al 2 O 3 using CF 4 and CHF 3 chemistries, and their findings show high etch rates for these chemistries and the feasibility for multipattern optical lithography processing.…”

Section: ■ Introductionmentioning

confidence: 99%

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Fluorination of an Alumina Surface: Modeling Aluminum–Fluorine Reaction Mechanisms

Padhye¹,

Aquino

Tunega

et al. 2017

ACS Appl. Mater. Interfaces

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Density functional theory (DFT) calculations were performed to examine exothermic surface chemistry between alumina and four fluorinated, fragmented molecules representing species from decomposing fluoropolymers: F, HF, CHF, and CF. The analysis has strong implications for the reactivity of aluminum (Al) particles passivated by an alumina shell. It was hypothesized that the alumina surface structure could be transformed due to hydrogen bonding effects from the environment that promote surface reactions with fluorinated species. In this study, the alumina surface was analyzed using model clusters as isolated systems embedded in a polar environment (i.e., acetone). The conductor-like screening model (COSMO) was used to mimic environmental effects on the alumina surface. Four defect models for specific active -OH sites were investigated including two terminal hydroxyl groups and two hydroxyl bridge groups. Reactions involving terminal bonds produce more energy than bridge bonds. Also, surface exothermic reactions between terminal -OH bonds and fluorinated species produce energy in decreasing order with the following reactant species: CF > HF > CHF. Additionally, experiments were performed on aluminum powders using thermal equilibrium analysis techniques that complement the calculations. Consistently, the experimental results show a linear relationship between surface exothermic reactions and the main fluorination reaction for Al powders. These results connect molecular level reaction kinetics to macroscopic measurements of surface energy and show that optimizing energy available in surface reactions linearly correlates to maximizing energy in the main reaction.

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Section: Acs Applied Materials and Interfacesmentioning

confidence: 76%

Section: ■ Introductionmentioning

confidence: 99%

Fluorination of an Alumina Surface: Modeling Aluminum–Fluorine Reaction Mechanisms

Padhye¹,

Aquino

Tunega

et al. 2017

ACS Appl. Mater. Interfaces

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“…85,86 The piezoelectric properties of AlN 87 have additionally made it of interest as a transducer material in surface acoustic wave and NEM devices. 43,88 The high resistance of AlN to fluorinated plasmas 89 has further lead to its use as a plasma etch stop, 33 hard mask, 90,91 and Cu capping layer 33 in microelectronic device applications.…”

Section: Ecs Journal Of Solid State Science and Technology 6 (10) N1mentioning

confidence: 99%

Review—Investigation and Review of the Thermal, Mechanical, Electrical, Optical, and Structural Properties of Atomic Layer Deposited High-kDielectrics: Beryllium Oxide, Aluminum Oxide, Hafnium Oxide, and Aluminum Nitride

Gaskins

Hopkins

Merrill

et al. 2017

ECS J. Solid State Sci. Technol.

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Atomic layer deposited (ALD) high-dielectric-constant (high-k) materials have found extensive applications in a variety of electronic, optical, optoelectronic, and photovoltaic devices. While electrical, optical, and interfacial properties have been the primary consideration for such devices, thermal and mechanical properties are becoming an additional key consideration for many new and emerging applications of ALD high-k materials in electromechanical, energy storage, and organic light emitting diode devices. Unfortunately, a clear correspondence between thermal/mechanical and electrical/optical properties in ALD high-k materials has yet to be established, and a detailed comparison to conventional silicon-based dielectrics to facilitate optimal material selection is also lacking. In this regard, we have conducted a comprehensive investigation and review of the thermal, mechanical, electrical, optical, and structural properties for a series of prevalent and emerging ALD high-k materials including aluminum oxide (Al 2 O 3 ), aluminum nitride (AlN), hafnium oxide (HfO 2 ), and beryllium oxide (BeO). For comparison, more established silicon-based dielectrics were also examined, including thermally grown silicon dioxide (SiO 2 ) and plasma-enhanced chemically vapor deposited hydrogenated silicon nitride (SiN:H). We find that in addition to exhibiting high values of dielectric permittivity and electrical resistance that exceed those of SiO 2 and SiN:H, the ALD high-k materials exhibit equally exceptional thermal and mechanical properties with coefficients of thermal expansion ≤ 6 × 10 -6 / • C, thermal conductivites (κ) of 3-15 W/m K, and Young's modulus and hardness values exceeding 200 and 25 GPa, respectively. In many cases, the observed extreme thermal/mechanical properties correlate with the presence of crystallinity in the ALD high-k films. In contrast, some of the electrical and optical properties correlate more strongly with the percentage of ionic vs. covalent bonds present in the high-k film. Overall, the ALD high-k dielectrics investigated concurrently exhibit compelling thermal/mechanical and electrical/optical properties. The drive to reduce gate leakage currents in highly scaled complementary metal-oxide-semiconductor (CMOS) transistors has led to the exploration and development of a wide variety of high-dielectricconstant (high-k) materials to replace silicon dioxide (SiO 2 ) as the insulating gate dielectric material.1-8 Many of these same high-k materials have found additional applications in future non-CMOS logic and memory storage products such as solid-state electrolytes in resistive switching devices, 9,10 tunnel barriers in spin-transport devices, 11 and as a ferroelectric in magnetoelectric devices. While electrical, physical, and thermodynamic properties have clearly been a key consideration in all of the above applications, thermal properties have become an additional important consideration for higk-k dielectrics as aggressive dimensional scaling of devices has created the need to dissipate ...

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“…We focus on carboranethiol SAMs on copper, based on the archetypal thiol–metal monolayer chemistry. , Carboranethiols have been previously shown to form ∼1 nm thick monolayers on a series of metals, , with demonstration of corrosion resistance on silver and the ability to modify the surface electronic properties of gold, , silver, − and germanium . The unique properties of boron-based materials, and carborane-based materials in particular, including mechanical, thermal, and chemical robustness, − unique etch chemistry, as well as tunable electronic, optical, and electrical properties, , make these of interest for a multitude of additional nanoelectronic applications including barrier layers, etch stops, and other patterning assist layers. − …”

Section: Introductionmentioning

confidence: 99%

Effect of Heat and Plasma Treatment on Carboranethiol Self-Assembled Monolayers on Copper

Thapa,

Dorsett,

Bale

et al. 2023

J. Phys. Chem. C

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Carborane (C2B10H12) molecules are unique precursors for self-assembled monolayer (SAM) applications. These 3D, icosahedral (12-vertex) molecules allow for the formation of well-ordered layers, potentially with fewer defects than traditional linear alkyl SAMs, and are amenable to cross-linking via labile H atoms with a variety of mechanisms including heat, plasma, and radiation (e.g., UV, e-beam). We have investigated the deposition of SAMs of 1,2-dithiol-ortho-carborane (O) and 9-thiol-meta-carborane (M) on copper from the vapor phase in ultrahigh-vacuum conditions, along with the effect of thermal (150–400 °C) and plasma (N2, H2, Ar, O2) postgrowth treatment. Both films show rapid deposition in the vapor phase with approximate monolayer or few layer coverage, as well as a mixture of physisorption (thiol adsorption) and chemisorption (thiolate binding). Both films additionally show notable stability to thermal treatment up to 400 °C, with only gradual (not abrupt) decrease in boron coverage and minor changes in chemical composition/makeup; however, with the monothiol derivative M showing greater loss of boron and greater oxidation. Nitrogen (N2) plasma treatment leads to partial nitrogenation of boron, while hydrogen (H2) and argon (Ar) plasma treatments lead to partial oxidation of boron, with some parasitic growth (increase in B coverage) especially for the dithiol derivative O. Oxygen (O2) plasma treatment shows an aggressive oxidation (of boron, carbon, sulfur, and copper), but appears to passivate the layers (i.e., the boron oxide based layer formed remains stable and does not change with further plasma exposure). Both heat and plasma treatments reduce copper oxide at the interface and increase thiolate binding (thus conceivably stabilizing the films). Indeed, exposure to N2 plasma appears to further stabilize the films toward heat treatment. These findings highlight that these carboranethiol SAMs represent a robust option for various functional and protective layer applications, and that heat and plasma may be used to further stabilize these films, to modify their properties, or as part of a more complex fabrication scheme.

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Boron and high-k dielectrics: Possible fourth etch stop colors for multipattern optical lithography processing

Cited by 9 publications

References 55 publications

Fluorination of an Alumina Surface: Modeling Aluminum–Fluorine Reaction Mechanisms

Fluorination of an Alumina Surface: Modeling Aluminum–Fluorine Reaction Mechanisms

Review—Investigation and Review of the Thermal, Mechanical, Electrical, Optical, and Structural Properties of Atomic Layer Deposited High-kDielectrics: Beryllium Oxide, Aluminum Oxide, Hafnium Oxide, and Aluminum Nitride

Effect of Heat and Plasma Treatment on Carboranethiol Self-Assembled Monolayers on Copper

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