We have demonstrated fluidic chip self-assembly on Si wafers for fabricating three-dimensional integrated circuits. In this self-assembly technique, small droplets of hydrofluoric acid were employed to simultaneously align many millimeter-scale chips and directly bond them to the hydrophilic bonding areas formed on the host wafers by oxide–oxide bonding. The liquid surface tension enables many Si chips to be self-assembled with the highest alignment accuracy of 50 nm. In addition, many chips were tightly bonded to the hydrophilic bonding areas without applying a mechanical force after the liquid was evaporated at room temperature.

We develop novel micro-bumping technology to realize small size, fine pitch and uniform height Cu/Sn bumps. Electroplated -evaporation bumping (EEB) technology, which is a combination of Cu electroplating and Sn evaporation, is developed to achieve uniform height of Cu/Sn bumps. We develop CMOS compatible dry etching processes for removing sputtered Cu/Ta layers to achieve small size and fine pitch Cu/Sn bump. 5 µm square and 10 µm pitch Cu/Sn micro-bumps are successfully fabricated for the first time. Bump height variation is 5 µm ±3 % (95%, 2σ), which is uniform compared to electroplated Cu/Sn bumps. We evaluate micro-joining characteristics of Cu/Sn micro-bumps. Good I-V characteristics are measured from the daisy chain consisting of 1500 bumps with 10 µm square and 20 µm pitch. Resistance of Cu/Sn bump is 35 mΩ/bump, which is very low value compared to electroplated Cu/Sn bumps.

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A new magnetic nanodot (MND) memory with FePt nanodots was proposed. The FePt nanodots dispersed in SiO2 insulating film was successfully fabricated by self-assembled nanodot deposition (SAND). The size of the FePt nanodot can be controlled by SAND with a different target area ratio of the FePt pellets area in the SiO2 target. Thermal annealing converts the magnetic properties of the FePt nanodots from antiferromagnetic into high coercivity ferromagnetic without thermal agglomeration. An L10 face-centered tetragonal (fct) FePt MND film was successfully formed which acted as a charge retention layer. Furthermore, the fundamental characteristics of the MND memory were investigated using magnetic metal oxide semiconductor (MOS) capacitor devices.