Technologies

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Ebara Engineering Review No.222

Production of High-purity Hydrogen from Biogas using Solid Oxide Electrolysis Cells

by Hiroyuki YAMADA, Hiroshi YOKOTA, Manabu NOGUCHI, Shunsuke SHIMIZU, & Tohru KATO

A novel energy-saving process for producing high-purity hydrogen has been developed. Pretreated biogas, such as by desulfurization, is fed into the anode side of solid oxide electrolysis cells, while steam is fed into the cathode side of the same. High-purity hydrogen becomes produced by electrolysis at a temperature exceeding 700℃. Performance test results indicated the effectiveness of this process which was confirmed to be capable of producing hydrogen by low-voltage electrolysis. The configuration of this process is simple and various biogas from various biomass sources could be used for producing hydrogen. This process can be also applied at facilities which produce various low-grade reductive gases.

Keywords
Hydrogen production, Biomass, Biogas, Solid oxide electrolysis cell, Steam reforming, Steam electrolysis, Digestion gas, Gasification of biomass, SOHG

Development of Cu Damascene Electroplating Machines for Interconnects on Highly Resistive Substrates

by Hiroyuki KANDA, Junko MINE, Satoru YAMAMOTO, Keiichi KURASHINA, Keisuke HAYABUSA, Akira SUSAKI, & Tsutomu NAKADA

A next-generation interconnect technique for Cu damascene electroplating machines has been developed. This leading-edge technique, which features Cu plating on thin Ru seeds, reduces the terminal effect and enhances uniformity by the placement of a highly resistive element between anodes and cathodes. This technique allows favorable film thickness distribution and film quality, and filling performance.

Keywords
Terminal effect, Cu electroplating, High resistive substrate, Porous resistive element, Ru seed, Uniformity, Filling performance, Surface roughness, Resistivity

Control System Backup Unit for High-head Packaged Booster System

by Tomoharu TEJIMA, Takahide KOMATSU, Sachiko MIYAUCHI, Kazuhiro KANEDA, & Nobuhiro HIGAKI

A control system backup unit for a high-head, computerized, packaged water supply booster system (Model F3100 for high-rise buildings) has been developed. This backup unit makes it possible to supply water, much in the same way as during normal operation, when there are occurrences of irregularities, including CPU board and pressure sensor malfunctions. The unit's 2 CPU board design has enabled it to be compact, thus minimizing installation space. The automatic switchover to the backup system enables minimal water stoppage when the main control system malfunctions. An optimal, continuous water supply has been made possible by an estimated constant end pressure control function.

Keywords
Control system backup unit, High-head, Packaged booster system, Pressure control, Backup operation, Controller, Pressure sensor, Backup circuit, Communication, Water stoppage

Application of a UV Treatment System to a Water Purification Process

by Katsuyuki SASAKI, Kazuo HAGIWARA, & Kensuke ONDA

A novel UV treatment system has been developed for use in water purification processes as a measure against chlorine-resisting pathogens, in particular Cryptosporidium. The following outlines the R&D of this system and provides data on actual application at a water purification plant.

Keywords
Cryptosporidium, Inactivation, Water purification, Ultraviolet radiation, UV dose, Low-pressure UV lamp, Medium-pressure UV lamp, Bromate

Bevel Polishing System for Semiconductor Devices

by Masunobu ONOZAWA

A bevel polishing system, the EAC 300bi-hp, has been released into the market to answer demands in the semiconductor for higher throughput, footprint shrinkage, and lower cost of consumables (CoC). This unprecedented flexible system upgrades the former model, the EAC 300bi-T, which is attaining a boost in the yield of mass produced semiconductor devices. In particular, this system enables a 3.3 time increase in throughput, a 16% reduction in footprints, and about a 70% reduction in CoC, compared to the same by conventional such systems.

Keywords
Wafer edge, Wafer bevel, Bevel polishing, Immersion lithography, Wafer thinning, Knife-edge, Edge bead, Etching, Edge exclusion, High-K

Lecture on Corrosion and Corrosion Protection of Seawater Pumps - Part 3: Galvanic Corrosion and Cathodic Protection -

by Matsuho MIYASAKA

Special attention is required for galvanic corrosion in seawater as, depending on conditions, its speed of progress can become multiple-fold than that of other corrosion (of single material) in seawater. When materials constituting parts with different corrosion potentials are used together in seawater, macro-cells form between these parts, with seawater as the electrolyte, and galvanic corrosion promotes the corrosion of materials whose potential is on the base side. In contrast, corrosion of materials with their potential on the noble side becomes inhibited. Cathodic protection (galvanic anode and impressed current) is a method which makes effective use of this corrosion inhibition phenomenon. The following discusses an actual case of galvanic corrosion in a seawater pump, features and protective measures, as well as the features and application of cathodic protection.

Keywords
Corrosion, Seawater, Pump, Galvanic corrosion, Cathodic protection, Galvanic protection, impressed current protection, Sacrificial anode, Potential, Polarization curve