Formation and Evaluation of Electroless-Plated Barrier Films for High-Aspect-Ratio Through-Si Vias

Miyake, Hiroshi; Inoue, Fumihiro; Yokoyama, Takumi; Shimizu, Tomohiro; Tanaka, Shukichi; Terui, Toshifumi; Shingubara, Shoso

doi:10.1143/jjap.50.05ed01

Cited by 4 publications

(4 citation statements)

References 19 publications

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“…Electroless deposition (ELD) is another candidate, which conventionally requires catalytic underlayer, and recently becomes possible on the insulating underlayers using Au nanoparticle catalyst. [13][14][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.…”

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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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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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“…It is difficult to deposit uniform Co-W- B film in a high-AR TSV. We consider that Control of the deposition profile by use of inhibitor such as SPS is needed to achieve conformal deposition [12]. We attempted the addition of SPS in the plating bath.…”

Section: Resultsmentioning

confidence: 99%

Control of Adhesion Strength and TSV Filling Morphology of Electroless Barrier Layer

et al. 2013

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In this study, we investigated to control adhesion property of the electroless plated barrier layer on SiO2 by addition of saccharin and its deposition profile in a high aspect ratio TSV with inhibitor and saccharin. We achieved high adhesion strength of barrier layer by addition of suitable amount saccharin. Furthermore, we succeeded in the formation of thin continuous electroless barrier layer for a high aspect ratio TSV with addition of both inhibitor and saccharin. The proposed highly adhesive and conformal electroless barrier layer formation would provide a highly reliable all-wet TSV filling process.

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“…[1][2][3][4][5] A key technology in 3D-LSI is the fabrication of through-silicon vias (TSVs), which function as interconnections between LSI chips. [6][7][8][9] Si etching is one of the most important processes for the formation of TSVs because it is necessary to create high-aspect-ratio holes on Si substrates. TSV holes are generally fabricated using deep reactive-ion-etching (D-RIE).…”

Section: Introductionmentioning

confidence: 99%

Effect of etching solution concentration on preparation of Si holes by metal-assisted chemical etching

Murata

Yorioka

Shiraiwa

et al. 2022

Jpn. J. Appl. Phys.

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The effect of the etching solution concentration on the etching profile of vertical microscale holes formed on a Si(100) substrate by metal-assisted chemical etching (MacEtch) was investigated. MacEtch was performed at different solution concentration ratios (characterized by their molar ratio ρ=[HF]/([HF]+[H2O2])), and the Au catalyst split above a certain concentration ratio. The Au-Si interface in the samples after MacEtch was observed using transmission electron microscopy (TEM), which revealed that there was a porous SiOx interlayer between the Au and Si, and that the SiOx layer became thinner as the concentration ratio increased. The interlayer almost disappeared under solution conditions when the catalyst was split. We propose two hypotheses for the mechanism of catalytic fracture during MacEtch: chemical fracture due to Si atoms diffusing into the grain boundaries of polycrystalline Au by Au-Si interdiffusion, and mechanical fracture due to stress on the catalyst caused by heterogeneous etching.

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Formation and Evaluation of Electroless-Plated Barrier Films for High-Aspect-Ratio Through-Si Vias

Cited by 4 publications

References 19 publications

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

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

Control of Adhesion Strength and TSV Filling Morphology of Electroless Barrier Layer

Effect of etching solution concentration on preparation of Si holes by metal-assisted chemical etching

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