A transparent super-hydrophobic polymer film was prepared by the screen printing method. Both urethane particles and colloidal silica were employed as fillers of the paste for printing. Colloidal silica effectively improved the rheological property of the paste and the urethane particles provided proper roughness. By mixing different roughness dimension, transparency, durability and super-hydrophobicity were satisfied in the prepared film simultaneously. This work demonstrated that proper filler selection is one of the key factors for the processing of multi-functional polymer films by the screen printing method.
The formation of LSI copper minute wiring by the electroless plating process is expected to become a dominant process for LSI interconnection because of the advantages in obtaining a film of uniform thickness on a dielectric film. Moreover, there is a possible application in three-dimensional wiring and three-dimensional mounting, which use the ball chip technology. However, the conformal deposition of metal basically takes place in electroless plating. The copper electroless deposition was done using neutral electroless plating after the copper seed layer of the sillicon wafer surface had pre-adsorbed PEG 4000 under the condition of coexistence with chloride ions. In the method utilizing pre-adsorption, a minute contacthole can be filled with copper without causing a seam due to the effect of the pre-adsorbed additive. The copper film obtained from this process is advantageous in electromigration (EM) resistance, because the priority orientation the (111) plane, which is the close-packed plane of the fcc structure, is shown and the crystallite size is 37nm. The specific resistance of the copper film is 1.85μΩ·cm.
Diamond synthesis onto iron substrate was tried by hot-filament chemical vapor deposition (HFCVD). Diamond can be synthesized at an atmospheric pressure by spraying a source gas onto an iron substrate with a nozzle. Diamond crystal grows to a size of about 20μm in 180 min. Diamond synthesized by the present method contains only a small amount of non-diamond carbon. Diamond synthesis on a silicon wafer is also enhanced by spraying a source gas onto a substrate like an iron case.
This paper describes the effects of pulse voltage application on the basic characteristics of electrochemical etching of NiTi shape memory alloy in LiCl-ethanol solution. The influence of dissolves products on etching characteristics has been also considered. The etched surface tended to be rough in the case of pulse etching under a low pulse duty ratio, under low applied voltage and with a wide etching pattern. The etch rate was about 4μm/min in the case of DC etching ; on the other hand, the etch rate could be suppressed below 0.5μm/min in the case of pulse etching with linear dependence on the duty ratio. Etch factor (etched depth/side etching width) increased above 2.0 with a wide pattern in the case of pulse etching because the dissolved products can be diffused out from the etched groove in the OFF-time of the pulse. However, there was little drastic effect of pulse etching on the etch factor when the pattern was narrower than 60μm because of the difficulty of the diffusion. It has become apparent that the dissolved products are necessary to obtain a uniform etched surface ; however, the dissolved products inhibit the high etch factor. Suitable etching conditions should be selected according to the application.
Silica films have been synthesized on a polymeric substrate, that is, polyethylene terephthalate (PET), by low-temperature plasma-enhanced chemical vapor deposition using an organosilicon compound and oxygen. Scanning electron microscope images clearly showed that the silica growth process depended on deposition conditions, including substrate surface conditions and the presence of activated oxygen species. Fragments of the organosilicon compound molecules are thought to adsorb selectively on energetically advantageous areas of the PET substrate. Dome-shaped silica structures formed in this manner on the polymeric surface in the early stage of the deposition. When no active oxygen species existed in the plasma, the boundaries between these domes remained in the deposited film even when the deposition was further prolonged. On the other hand, in the presence of activated oxygen species in the plasma, these silica domes fused to each other and, consequently, a fairly smooth film was formed at an increased deposition time. Finally, densely-packed silica films were successfully formed on the PET substrates.
Lead has serious influences on the human body, and lead release from water supply lead pipe into tap water becomes one of the serious problems. The regulations for lead concentration in tap water have gradually become stricter, and will likely be even more stringent in the future. As one of the methods for dealing with the problem of lead water supply pipes prudently, the authors took notice of the electrochemical surface reforming method, and the modification of the lead surface was tried using the repetition technique of the anode-cathode alternate potential sweep. A phase-mixed modified layer, which consists of lead carbonate, lead hydroxide, lead monoxide and lead dioxide, was formed by electrolysis using alkaline electrolyte including carbonate ions. With this modified surface layer, it was possible to suppress the elution amount of lead to about 25 % of that of untreated lead.
Sodium allylsulfonate, saccharin, naphthalene-1, 3, 6-trisulfonic acid trisodium, and 2-butyne-1, 4-diol were added to a Watt bath to study the effects of additives on the characteristics of electroplated nickel films, i.e., crystal structure, hardness, and throwing power. When the additives having a sulfo group in the molecular structure were used, the obtained nickel films had a crystal structure preferentially oriented to a (111) face, and tended to have higher hardness and a small crystallite size. The electroplated nickel films with the highest hardness and the best throwing power were obtained, when allylsulfonate having both allyl and sulfo groups was added.
Electroless plated composite films prepared from a bath containing both h-BN particles and hydrophilic carbon black particles showed lower friction coefficient than same films prepared in a bath containing only dispersed h-BN.
The electroplating of copper has been done by using a thin film of gel electrolyte. The electrochemical behavior of the copper plating cell was investigated by electrochemical methods involving an impedance method. The current efficiencies of both copper deposition and copper counter electrode dissolution did not depend on the thickness of the gel electrolyte. It was confirmed that the copper plating could be accomplished using a gel electrolyte of 1mm thickness. The cell voltage increases due to solution resistance with the increase of gel electrolyte thickness. Therefore, decrease of electrical power requirement and minimization of the plating cell can be expected by electroplating using a thin gel electrolyte.