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Kyoto, Japan

Howlader M.M.R.,McMaster University | Kagami G.,Shinko Seiki Co. | Lee S.H.,University of Texas at Dallas | Wang J.G.,University of Texas at Dallas | And 2 more authors.
Journal of Microelectromechanical Systems | Year: 2010

To investigate the sequentially plasma-activated bonding (SPAB) mechanism of silicon/silicon wafers, the surface hydrophilicity, and the interface voids, nanostructures and chemical compositions that control the bonding quality, such as bonding strength, have been observed. Although the sequentially plasma-activated surfaces are hydrophilic, the SPAB mechanism is not identical to the hydrophilic bonding. SPAB shows high bonding strength at room temperature and water rearrangement below 150 °C, which removes the water from the interface to the bulk. This results in a thinner amorphous silicon oxide layer at the interface. Further heating of the bonded wafers desorbs water from the bulk. The heating at 225 °C starts producing hillocks at the interface, which turn into voids at temperatures above 400 °C for absorbing the hydrogen gas produced from the desorbed water at the interface. The new and bigger voids are due to the hydrogen gas at 600 °C and start accumulating at 800 °C, resulting in bubbles caused by the accumulation of voids at the preferential sites. No nitrogen exists either in silicon or in the amorphous SiO2 layer at the interface. The Si-L2,3 edges from the amorphous silicon oxide at the bonded interface are identical to those of the standard SiO2. © 2006 IEEE. Source

Howlader M.M.R.,McMaster University | Yamauchi A.,Bondtech Co. | Suga T.,University of Tokyo
Journal of Micromechanics and Microengineering | Year: 2011

Flip chip nanobonding and interconnect system (NBIS) equipment with high precision alignment has been developed based on the surface activated bonding method for high-density interconnection and MEMS packaging. The 3σ alignment accuracy in the IR transmission system was approximately ±0.2 μm. The performance of the NBIS has been preliminarily investigated through bonding between relatively rough surfaces of copper through silicon vias (Cu-TSVs) and gold-stud bumps (Au-SBs), and smooth surfaces of silicon wafers. The Cu-TSVs of 55 μm diameter and the Au-SBs of 35 μm diameter with ∼6-10 nm surface roughness (RMS) were bonded at room temperature after surface activation using an argon fast atom beam (Ar-FAB) under 0.16 N per bump. Silicon wafers of 50 mm diameter with ∼0.2 nm RMS surface roughness were bonded without heating after surface activation. Void-free interfaces both in Cu-TSV/Au-SB and silicon/silicon with bonding strength equivalent to bulk fracture of Au and silicon, respectively, were achieved. A few nm thick amorphous layers were observed across the silicon/silicon interface that was fabricated by the Ar-FAB. This study in the interconnection and bonding facilitates the required three-dimensional integration on the same surface for high-density electronic and biomedical systems. © 2011 IOP Publishing Ltd. Source

He R.,University of Tokyo | Fujino M.,University of Tokyo | Yamauchi A.,Bondtech Co. | Suga T.,University of Tokyo
Japanese Journal of Applied Physics | Year: 2015

Low-temperature hydrophilic SiO2-SiO2 wafer bonding has been performed in vacuum by a new combined surface-activated bonding (SAB) technique. In this technique, wafers are irradiated by ion beam bombardment and simultaneously deposited with silicon by in situ silicon sputter deposition, and then terminated with Si-OH groups by water vapor exposure prior to bonding in vacuum. A surface energy of more than 1J/m2was achieved by 200°C postbonding annealing. A void-free oxide intermediate layer with a thickness of about 15 nm was observed at the bonding interface by transmission electron microscopy (TEM). The increased bonding energy can be attributed to the greater number of Si-OH formed through hydroxylation of the silicon deposited on the SiO2 surfaces. © 2015 The Japan Society of Applied Physics. Source

Bondtech Corporation | Date: 2014-06-29

autoclave systems having material handling capabilities, for use in technical industries, namely infectious medical waste treatment, aerospace composites, class lamination, rubber vulcanizing, wood treating, yarn setting, and medical waste management.

[Problem] To provide a substrate bonding technique having a wide range of application. [Solution] A silicon thin film is formed on a bonding surface, and the interface with the substrate is surface-treated using energetic particles/metal particles.

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