Copper-filled anodic aluminum oxide: A potential substrate material for a high density interconnection

Copper-filled anodized aluminum oxide (Cu-filled AAO) will be presented as a potential base material for bonding between the small pads of IC chips. This paper presents a potential material for low temperature bonding for 3D packaging. The material was prepared by filling metal Cu into isolated nano-holes of anodized aluminum oxide (AAO), which were formed by the anodic oxidation treatment of aluminum. The tips of nano-Cu filaments were exposed from AAO surface (Cu nano-nail) so as to bond to Cu pads. In 3D packaging, upper and lower chips can be connected using anisotropic conductive materials. In Cu-filled AAO, the electric conductivity appears only in the vertical direction along filled metal, and insulation property by AAO appears in the horizontal direction. As a result, the anisotropic conductivity ratio (vertical vs. horizontal) is 10 17 . Thermal anisotropy is also demonstrated, because the filled metal conducts heat in the vertical direction. The anisotropic thermal conductivity ratio is about 34. Thermal conductivity of Cu-filled AAO is 20 times higher than that of the conventional resin, used for under-fill materials. Cu-filled AAO is promising bonding material for the thermal management in 3D integration. The low-temperature-sintering technology using the metallic Nano particle is known already well. The exposed Cu nano-nail can be sintered similar to the metallic nanoparticles. We demonstrate the low temperature Cu-Cu bonding capability by using the Cu nano-nail. The direct bonding of Cu was achieved at 523K on this Cu nano-nail on Cu-filled AAO. (Abstract)

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“…The CTE value of Cu-filled AAO is 7.5ppmK -1 that had already reported. [5] It is about equal to Glass.…”

Section: B Charactarization Of Cu-filled Aao (Electrical Properties)mentioning

confidence: 99%

“…And technology that uses this material as a substrate material substitute for TSV and TGV has already reported. [5] Because copper filling AAO excelled in the heat control that was the problem of the laminated structure, the advantage will be expected if it was able to bond between IC devices directly.…”

Section: Introductionmentioning

confidence: 99%

Copper-filled anodized aluminum oxide a potential material for low temperature bonding for 3D packaging

Yamashita

Hotta

Kurooka

et al. 2015

2015 International Conference on Electronic Packaging and iMAPS All Asia Conference (ICEP-IAAC)

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“…Anodized aluminum oxide (AAO) films are aluminum-based materials composing with an individual cylindrical channel array with high hardness, 13 and they are a kind of excellent dielectric materials with dielectric constant ∼4.5 varying from 10 to 20 GHz. 14 Moreover, the CTE of AAO is 5.4 ppm/K, and it is capable with Si (2.5 ppm/K). Nevertheless, the AAO films were usually used as a template for synthesis of various nanowires and nanotubes, and will be etched out after electrodeposition.…”

Section: Introductionmentioning

confidence: 99%

“…Hence, more efficient and stable heat dissipation materials are required when electronic devices, especially for power devices, are assembled on substrates. , Copper (Cu) is an outstanding thermal and electrical conductor and is vastly used in electronic packaging, but it is hard to achieve the anisotropic interconnection due to its isotropic conductivities. Anodized aluminum oxide (AAO) films are aluminum-based materials composing with an individual cylindrical channel array with high hardness, and they are a kind of excellent dielectric materials with dielectric constant ∼4.5 varying from 10 to 20 GHz . Moreover, the CTE of AAO is 5.4 ppm/K, and it is capable with Si (2.5 ppm/K).…”

Section: Introductionmentioning

confidence: 99%

One-Step Fabrication of Copper Nanopillar Array-Filled AAO Films by Pulse Electrodeposition for Anisotropic Thermal Conductive Interconnectors

et al. 2019

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By using pulse electrodeposition, a copper nanopillar array (CuNPA) was filled into porous anodized aluminum oxide (AAO) films to achieve a highly thermal conductive interconnector with anisotropic property. After 120 min pulse deposition, CuNPA uniformly filled the pores of AAO with a pore-filling percentage of 99.4%, as the ion concentration in AAO pores can re-equilibrate to electrolyte concentration during the current-off period. The CuNPA-filled AAO film showed a high thermal conductivity of 153.12 W/(m·K) in the vertical direction and a low thermal conductivity of 3.43 W/(m·K) in the horizontal direction. Hence, the anisotropic ratio of the thermal conductivity reached 44.64. Moreover, the fabrication process was facile and cost-effective, showing a potential application prospect in the field of high-density packages and power electronic devices.

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“…Porous anodic aluminum oxide (AAO) is proposed here to be an alternative material for interposer technology. Research and development works have been done in templating AAO for high aspect ratio anisotropic nanowire fabrication and applications, [9][10][11] low cost metallic nanotip arrays fabrication, 12 and nano-patterning mask on Si wafer. 13 This work, instead, took advantage of the distinct anisotropic etching characteristic from nanoporous characteristic of AAO [14][15][16] to create structures with vertical sidewall was carried out to fabricate through via.…”

mentioning

confidence: 99%

Interconnects and Interposer in Porous Anodic Aluminum Oxide: The Fabrication Technology and Process Integration

Chan¹,

Bachman²,

Li³

2018

ECS J. Solid State Sci. Technol.

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Porous anodic aluminum oxide (AAO) features its interesting nanoporous structure which is capable of being used as a template for nanopatterning, highly anisotropic nanowire fabrication, and MEMs devices fabrication. In this work, AAO was demonstrated to be an interposer substrate for 2.5/3D packaging technology in microelectronics exploiting the unique etching characteristic of nanopores. Not only the high density vertical through via was fabricated but also metallized with Cu as void-less interconnect simply by using wet chemicals. Passive devices like inductors were embedded in AAO film after via metallization and re-distribution layer Cu electroplating which provide multifunctionalities to proposed AAO interposer. AAO with the special structural and etching properties plus its low electrical loss, thermal stability, and mechanical robustness, is a promising material for heterogeneous integration and advanced microelectronic packaging technology.

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Copper-filled anodic aluminum oxide: A potential substrate material for a high density interconnection

Cited by 11 publications

References 20 publications

Copper-filled anodized aluminum oxide a potential material for low temperature bonding for 3D packaging

Copper-filled anodized aluminum oxide a potential material for low temperature bonding for 3D packaging

One-Step Fabrication of Copper Nanopillar Array-Filled AAO Films by Pulse Electrodeposition for Anisotropic Thermal Conductive Interconnectors

Interconnects and Interposer in Porous Anodic Aluminum Oxide: The Fabrication Technology and Process Integration

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