Fumikazu Mizutani

Characterization of Anodic Films on Aluminum Formed in Carboxylate‐Based Nonaqueous Electrolyte Solutions

Anodic films were formed on aluminum at 0.5 A dm -2 to 50 V in a 1 mol dm -3 triethylmethylammonium hydrogen maleate/γ-butyrolactone solution of varying water content (10 to 1000 ppm). The resultant films were characterized by transmission electron microscopy, Auger electron spectroscopy, Fourier transform infrared spectroscopy, and x-ray absorption near edge structure analysis. The thickness, chemical composition, and structure of the resultant barrier-type films were affected markedly by water content with the incorporation of electrolyte components into the anodic films enhanced by decreasing water content. The film formed below 200 ppm of water proved to be an electropolymerized organic film containing a small amount of aluminum, while the film formed above 700 ppm of water was a different aluminum oxide containing a small amount of carbon. In the transition region between 200 and 700 ppm of water, a laminated composite film of high carbon content in the outer layer was produced. All the films showed a new infrared peak at 1610 cm -1 , which did not change upon annealing at 300°C. This peak was assigned to an Al=O stretching vibration. The permittivity of the films was lowered by incorporation of organic substances into the film material.

High thermal conductivity underfill for the thermal management of three-dimensional (3D) chip stacks

It has been experimentally clarified that one of the thermal resistance bottlenecks of a three-dimensional (3D) chip stack is interconnection (solder bumps and underfill) between stacked chips. High thermal conductivity underfill, which we call high thermal conductivity inter chip fill (ICF), is expected to reduce the thermal resistance of interconnection efficiently, because the area which is occupied by ICF is larger than solder bumps. It is shown by simulation how high thermal conductivity ICF contributes to decrease the thermal resistance of interconnection. Also material formulation of high thermal conductivity ICF is demonstrated.

Formation and electric properties of anodic oxide films on Al-Nd sputtered films in nonaqueous electrolyte solutions

Sputtered Al-Nd alloy films were anodized in nonaqueous electrolyte solutions at various current densities, on which the amounts of incorporated carbon species into the oxide films depend. The resultant oxide films were characterized by Fourier transform infrared (FTIR), cross-sectional transmission electron microscopy (XTEM), and secondary-ion mass spectroscopy (SIMS). Electrical properties such as relative permittivity and dielectric strength were also measured for these films. The FTIR peak position associated with Al-O stretching vibration was correlated with the relative permittivity and dielectric strength of the anodic oxide film. Since the peak position is dependent on the condition of anodization. FTIR measurement will be useful in developing high insulating oxide films for microelectronic devices.

An Outgas Free Passivation Technology for Semiconductor Vacuum Chamber using Advanced Anodic Oxidation

In order to apply the aluminum alloy to the semiconductor vacuum chamber, appropriate passivation surface process is essential. Following characteristics are required for the passivation film of advanced semiconductor chamber. 1) no outgas(H2O) 2) no heat crack 3) no corrosion by the process chemicals 4) no damage by the plasma irradiation 5) no catalyst effect to the decomposition of the process gas

Development of Barrier Anodic Oxide Al2O3 Passivations of Aluminum Alloy Surface for LSI/FPD Plasma Process Equipment

Aluminum alloys are key materials for advanced large-scale integration (LSI)/flat panel display (FPD) plasma process equipment to drastically improve the process performance. There exists a severe disadvantage for aluminum-alloy process chambers, however, i.e., very poor anticorrosion capability to halogen gas plasmas. Thus, the authors have developed very advanced Al 2 O 3 passivation films having a thickness of 0.1-0.4 μm on aluminum-alloy surfaces exhibiting complete anticorrosion resistance for various radicals such as hydrogen radicals H*, oxygen radicals O*, halogen radicals (Cl*,Br*,F*), and simultaneously various ion bombardments by using nonaqueous anodic oxidations. Porous alumite (alumilite) films having a thickness of 50-200 μm have been provided on aluminum-alloy chamber surfaces as anticorrosion films using aqueous anodic oxidations, particularly for reactive ion etching process chambers. But alumite films (Al 2 O 3 nH 2 O) include huge amounts of water molecules, resulting in the generation of water vapors in the process chamber and leading to the degradation of process quality and the generation of too many particles in the process chamber coming from water-molecule-originated gas-phase reactions. 1 Plasma process performance of LSI/FPD manufacturing is drastically enhanced by introducing a newly developed Al 2 O 3 passivated aluminum-alloy chamber to overcome all disadvantages of current plasma process equipment.

Development of the post-chemical mechanical polishing cleaner suppressing galvanic corrosion between copper and the Co barrier metal

To develop the post Cu-CMP cleaner, we investigate galvanic corrosion of Co as used barrier metal by electrochemical measurements. To elucidate relationship between cleaner composition and galvanic corrosion, corrosion potential is investigated by Tafel plot and corrosion current is measured by Liner Sweep Voltammetry (LSV). As results, LSV indicates variation of galvanic corrosion caused by chelator and inhibitor. Furthermore, result of LSV shows well agreement with etching rate of Co wafer which electrically connected with Cu wafer.

Chemically resistant anodic oxide films formed on Al–Nd alloy in non-aqueous electrolytes

Abstract Chemically resistant oxide films were formed by anodizing of Al–3 wt.% Nd alloy sputtered films in non-aqueous electrolytes that contain ammonium salicylate, ethylene glycol, and ethylene carbonate. The films were hardly etched by a typical etchant for Al thin films, while the films formed in conventional electrolytes were considerably etched. By secondary ion mass spectroscopy and atomic force microscopy, it was revealed that the films had a carbon rich outer layer.

Thermotropic liquid crystalline polyimides toward high heat conducting materials for 3D chip stack

Novel thermotropic liquid crystalline semi-aliphatic polyimide containing polysiloxane unit has been developed. The polyimide film exhibits high thermal stability and liquid crystallinity with lower transition temperature. Poly(amic acid) solution used as a precursor of the polyimide has very good surface wetting properties for a silicon wafer, resulting in homogeneous polyimide thin film formation on the wafer after thermal imidization below 200 °C. The silicon wafer coated with the polyimide thin film can be bonded to another silicon wafer, or to another polyimide film on heating at 270 °C with relatively low pressure. Moreover the bonding is repairable on heating again. It is proposed that the polyimide can be utilized as a polymer adhesive for three dimensional chip stack.