Step Coverage Quality of Cu Films by Supercritical Fluid Deposition Compared with Chemical Vapor Deposition

Momose, Takeshi; Sugiyama, Masakazu; Kondoh, Eiichi; Shimogaki, Yukihiro

doi:10.1143/jjap.49.05ff01

Cited by 19 publications

(16 citation statements)

References 31 publications

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“…Atomic layer deposition (ALD), in which precursor and reactant are supplied alternately to allow self-limiting surface reaction, , is a promising alternative candidate. Supercritical fluid deposition (SCFD), in which precursors in a high-pressure environment react via a quasi zeroth order surface reaction, is also a viable technique. Comparatively speaking, CVD enables a high deposition rate and thus is suitable for depositing nanometer-to-micrometer thick films onto 3D features.…”

Section: Introductionmentioning

confidence: 99%

Porous Membranes as Sacrificial Layers Enabling Conformal Chemical Vapor Deposition Involving Multiple Film-Forming Species

Shima

Funato

Satô

et al. 2020

ACS Appl. Mater. Interfaces

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We propose a new, concise method for conformal chemical vapor deposition (CVD) using sacrificial layers (SLs) to fill three-dimensional features with microscopic pores. SLs are porous membranes (e.g., ceramic felts) that filter film-forming species having high sticking-probability (η). CVD processes with multiple film-forming species generally suffer from poor conformality due to preferential film deposition at the inlets of features by the high-η species, such as reactive intermediates. An SL traps such high-η species before they reach the target features and selectively supplies film-forming species with lower η (e.g., source precursors or stable intermediates) that enables conformal film deposition. Here the trapping efficiency of an SL was predicted and a procedure for designing an optimal SL was established. The procedure was demonstrated by CVD of silicon carbide (SiC) with multiple film-forming species of high-η species (η = 8.0 × 10–3) and lower-η species (η = 5.9 × 10–5 and 2.2 × 10–7). The trapping of 99.2% of incident high-η species was achieved with an optimized SL, wherein the deposition rate (m/s) contribution by high-η species declined from 0.546 at the SL inlet to 0.014 at its outlet. Finally, using these optimized SLs, SiC-CVD filling of micron-scale trenches was demonstrated with an aspect-ratio of 16:1.

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Section: Introductionmentioning

confidence: 99%

Porous Membranes as Sacrificial Layers Enabling Conformal Chemical Vapor Deposition Involving Multiple Film-Forming Species

Shima

Funato

Satô

et al. 2020

ACS Appl. Mater. Interfaces

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“…This method uses the oxidation/reduction of organic compounds by oxidants/reductants in a supercritical fluid (SCF). [16][17][18][19][20] An SCF exists above the critical temperature and pressure of the fluid and exhibits intermediate properties of liquids and gases. These properties consequently provide SCFD with unique properties that are advantageous for device fabrication.…”

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confidence: 99%

One-Step Fabrication of Copper Thin Films on Insulators Using Supercritical Fluid Deposition

Uejima

Momose

Sugiyama

et al. 2013

J. Electrochem. Soc.

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A one-step fabrication method for direct supercritical fluid deposition (SCFD) of Cu on insulators was developed. This overcomes the limitation of conventional SCFD, which cannot directly deposit Cu on insulators. In our one-step method, a relatively small amount of an Mn precursor was mixed with a Cu precursor to deposit a CuMn x O y composite layer on an insulative underlayer. This underlayer then acted as a buffer layer, allowing subsequent Cu deposition. This method successfully achieved Cu deposition on insulators, including SiO 2 , boron phosphorus silicon glass (BPSG), and Parylene. The superior conformal deposition ability of conventional SCFD was also demonstrated using our one-step method, where Cu was deposited uniformly on an overhung test structure. Detailed analysis revealed that our one-step method was initiated by deposition of MnO x , which could include Cu, resulting in CuMn x O y film formation, followed by Cu deposition. The amount of the MnO x deposited during Cu deposition was negligible due to the much lower growth rate of MnO x compared with Cu. This process is useful for the fabrication of electronic devices having complex features and comprising various materials. . This paper is part of the JES Focus Issue on Electrochemical Processing for Interconnects.Microfabrication technologies, such as deep reactive ion etching (DRIE), 1-4 have enabled the fabrication of three-dimensional (3D) complex structures with extremely high aspect ratios (HAR), above 50 for instance, on the surface of silicon wafers. Thin-film technologies that enable conformal coatings on these features have been applied to a variety of electronic devices, including microelectromechanical systems (MEMS), 5-7 dynamic random access memory (DRAM), 8-10 and through silicon via (TSV), 11,12 to exploit the large surface area and to functionalize the devices. Chemical vapor deposition (CVD), which is a technology having good step coverage, cannot meet these demands. Electroless deposition (ELD) is another candidate, which conventionally requires catalytic underlayer, and recently becomes possible on the insulating underlayers using Au nanoparticle catalyst. 13-15 ELD is a wet process, and thus advantageous in simplicity of equipment, while supercritical fluid deposition (SCFD), which is a focus of this paper, requires incidental facilities including a high pressure pump and a pressure control system to realize deposition under high pressure environment. Nevertheless, SCFD seems to have more possibility to achieve conformal deposition on extremely high-aspect-ratio features. Because step coverage is determined by the balance between the transportation of the precursor by diffusion within the trenches and consumption of the precursor on the side walls by deposition reactions, higher diffusivity in SCFD (10 −7 -10 −8 m 2 /s) compared with that in liquid solution of ELD (10 −10 m 2 /s) leads to higher step coverage.SCFD is a novel approach that achieves conformal deposition onto HAR features. This method uses the oxidation/reduction...

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“…Flexible chip design will require complex shaped through-hole interconnections instead of traditional throughholes perpendicular to the substrate surface. 1) Several deposition techniques, such as electrochemical deposition (ECD), [2][3][4][5] physical vapor deposition (PVD), [6][7][8] and chemical vapor deposition (CVD), 7,[9][10][11][12][13][14][15][16] have been attempted so far. However, ECD and PVD are inappropriate for coating inside the high aspect ratio through-holes due to their poor step coverage.…”

Section: Introductionmentioning

confidence: 99%

Conformal Copper Coating of True Three-Dimensional Through-Holes Using Supercritical Carbon Dioxide

Watanabe

Takeuchi

Ueno

et al. 2012

Jpn. J. Appl. Phys.

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Properties of crystalline solutions are generally dependent not only on their chemical composition but also on the configurations of solute atoms and/or point defects. Quantitative knowledge of the configuration-dependent properties is therefore essential for materials design. The cluster expansion (CE) method has been widely used to describe the configurational properties. Increases in computational power and advances in numerical techniques enable us to perform a large set of systematic first principles calculations based on density functional theory (DFT) to be combined with CE calculations. In this paper, our procedure of CE with optimal selections of clusters and DFT structures is described. Two examples of such calculations are then shown. One is the cation arrangement in a series of spinel oxides. The other is arrangement of the oxygen vacancy in a series of tin sub-dioxides.

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Step Coverage Quality of Cu Films by Supercritical Fluid Deposition Compared with Chemical Vapor Deposition

Cited by 19 publications

References 31 publications

Porous Membranes as Sacrificial Layers Enabling Conformal Chemical Vapor Deposition Involving Multiple Film-Forming Species

Porous Membranes as Sacrificial Layers Enabling Conformal Chemical Vapor Deposition Involving Multiple Film-Forming Species

One-Step Fabrication of Copper Thin Films on Insulators Using Supercritical Fluid Deposition

Conformal Copper Coating of True Three-Dimensional Through-Holes Using Supercritical Carbon Dioxide

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