Production of compound eyes lens metal molds are cutting method etc. But, the report of plating method investigated. Therefor, production of compound eyes lens metal molds by bright plating method were investigated. We was studied production of compound eyes lens metal mold by bright plating method. We made a hemisphere metal mold with a surface roughness (Rmax) of 40∼120nm and the radius curvature of 0.44∼1.4mm when we controlled a nickel sulfate concentration and a integrating current and a hole diameter of photo-resist pattern and a electro-conductive film. Rmax, was lowest with a nickel sulfate concentration of 20∼30%, and decreased with increasing an anode size, e.g. maximum Rmax, was 40nm with a nickel sulfate concentration of 20% and an anode size of 0.25dm2. Curvature radius decreased with increasing a nickel sulfate concentration, and decreased with increasing a integrating current. When we used copper electro-conductive with low electric resistance, curvature radius was smaller than it used nickel electro-conductive film with high electric resistance. When a hole diameter of photo-resist pattern increased, curvature radius was a large.
In the palladium plating leadframe, nickel and palladium are plated over the whole surface including outerleads in the leadframe manufacturing process. Users have pointed out plating film cracks after bending of outerleads. The most thickness of the plating film is nickel. We changed nickel plating conditions and studied the influence on plating film cracks, with the following results: (1) Nickel plating film from a sulfamate bath produces fewer cracks than that from a Watt's bath and is suitable for the underlayer of palladium plating film. (2) Internal stress in nickel plating film rises abruptly when the sulfamate bath pH exceeds 5.0. Even then, cracks did not grow larger, indicating no correlation between internal stress and crack extent. (3) Plating conditions should be monitored to maintain plating thickness because current efficiency changes with plating conditions. Their influence on cracks is small.
Tape carriers have been used as BGA substrates because of their thin, fine circuits and high manufacturing accuracy. Electroless gold plating on tape carriers has become required. Electroless gold plating tape carriers having good gold wire bondability and ball solderability are being developed. We studied the influence of electroless gold plating thickness on wire bondability and ball solderability, with the following results: (1) The pull strength of gold wires on tape carriers with 0.2μm and over gold plating thickness was 0.07N or more. (2) The shear strength of solder balls on tape carriers with 0.2μm and below gold plating thickness was 3N or more after heat aging at 150°C for 500h. (3) Tape carriers with 0.2μm gold plating film had good wire bondability and ball solderability.
The paper reports a new autocatalytic electroless gold plating bath that achieves almost neutral, low temperature bath conditions and excellent process stability without cyanide. The bath contains a thiosulfatesulfite mixed complex of Au (I) as the gold source and two reducing agents, thiourea and hydroquinone. The thiourea acts as the primary reductant for the gold complex, while the hydroquinone recycles thiourea by reducing the intermediate thiyl radical derived from thiourea oxidation. Therefore hydroquinone functions as a thiourea regenerator. This unique cooperative reductant system offers superb bath stability. The bath has been applied not only to the most advanced mainframe MLC boards but also to a variety of very fine pitch organic PWBs manufacturing process.
Laser-enhanced electroless gold plating on polyimide resin plate was conducted in a cyanide-free bath. Electroless gold plating on polyimide resin was possible when a breakage protector such as a ceramic or copper plate was set behind the resin plate. The protector acts as a heat scatterer. Using a copper protector with higher heat conductivity produced a better gold deposit than using the ceramic plate.
We studied the development of alkaline and electroplating baths of Sn-Ag binary alloy using 5, 5-dimethylhydantoin (DMHy) as a Pb-free solder plating bath under various conditions, such as metal content, complex agent concentration, pH, current density and bath temperature. From these results, e. g., adding large amount of DMHy, pH 10.5, high current density, etc., electroplating films of Sn-Ag alloy having eutectic and constant composition were obatined. Surface morphology and solder wetting time of Sn-Ag alloy electroplating films become roughened with increasing film thickness. The melting point of Sn-Ag alloy electroplating films was about 221°C, similar to that of Sn-Ag ingot, and its phase structure consisted of eutetic structure of β-Sn and the ε phase (Ag3Sn).
Anodic current density-potential curves of Sn, Ag, Pt, and graphite were measured to obtain informations on the selection of anode materials in ammonium citrate-potassium iodide baths for Sn-Ag alloy plating. The Sn anode was dissolved at small overpotentials in ammonium citrate solutions containing iodide and showed a very smooth electrode surface. However, a displacement deposition of rough Ag was observed when solutions contained Ag+. The Ag anode also dissolved at small overpotentials. Nevertheless, AgI was precipitated at the anode and therefore the limiting current densities were smaller than 10mA/cm2. The main electrode reaction at the Pt and graphite anode was oxidation of iodide to form I3-. This reaction also occurred at the Sn and Ag anode at high overpotentials. Sn2+ species was chemically oxidized by I3- formed at the anode, accumulating Sn4+ species in baths. To prevent both Ag displacement deposition and anodic oxidation of iodide, the electrode potential of the anode in Sn-Ag alloy plating baths must be maintained between -0.2V and 0.4V vs. NHE.
An electroless Palladium plating aiming “no emission” were investigated using formic acid as the reducing agent, and monoaminodicarboxylic acid as the complexing agent. Stability constants of Pd2+ complexes are log K1=15, log K2=6 for L-glutamic acid (Glu), and log K1=15, log K2=7 for L-aspartic acid (Asp). The potential-pH equilibrium diagram for Pd2+-Glu (or Asp) and HCOO--HCO3- systems indicates that electroless palladium plating is thermodynamically possible when formic acid is used as the reducing agent. These complex baths exhibited good storage stability, and pure palladium films were deposited autocatalytically. Results of testing for solderability and for electrical contact resistance indicated that electroless pure palladium plating is suitable as an alternative to electrolytic and electroless gold plating of electronic parts.
In electroless copper plating using hypophosphite as a reducing agent, nickel ions are generally added to the electroless copper plating bath to initiate the auto catalytic reaction, because catalytic activity for anodic oxidation of hypophosphite on copper is low. If nickel ions are excluded from the plating bath, the plating reaction is be initiated only at palladium-catalyzed sites on resin and reaction finally terminates on deposited copper. Adhesion strength between roughened epoxy resin and deposited copper by electroless copper plating using hypophosphite was studied. The plating reaction on palladium-catalyzed epoxy resin initiated and terminated when copper is deposited about 0.3μm. Accordingly, the amount and activity of adsorbed Pd on resin are influenced by the following plating reaction. Adsorbed Pd was increased by immersion in 0.3g/dm3-PdCl2 solution followed by immersion in 0.25mol/dm3-NaH2PO2 solution after conventional mixed catalyst processing. Adhesion strength between epoxy resin and deposited copper is about 1.53kgf/cm. Adhesion strength is higher than that in the plating using formaldehyde since deposited copper reaches small complicated etched pits.
Printed wiring board density is increasing with progress in electronic devices. Build-up has attracted in high-density mounting. Via-hole plating is used for standard layer-to-layer connection. The process becomes complicated because the insulation layer must be planarized by filling via holes with insulation resin or conductive paste after plating. We studied the possibility of via filling by controlling the current waveform of current and additive agents for copper electroplating. Via-filling is achieved by applying low current during plating. Current waveform control and additive agent selection were affected to via filling.
Electroless plating using dimethylamine-borane (DMAB) as a reducing agent showed poor selectivity of deposition on patterned surfaces formed using photoresist. In a basic study on selectivity, we studied the effect of complexing agent on micro-pattern formation using electroless NiB plating. Changing species and concentrations of complexing agents changed the formation of film deposition. We fabricated micro-pattern formation using electroless plating by selecting complexing agents. The combination of glycine and ammonium sulfate was found to be optimal to obtaining deposition with a smooth surface without voids only onto the catalyzed surface. It is thought that selectivity relates to stability of metal complexes rather than deposition rate and/or mixed potential. We found that the high stability of complexing agent yielded high selectivity.
Amorphous (a-) Fe-B alloy films for micro-magnetic device applications were fabricated by electrodeposition. It was found that an appropriate KBH4 concentration greater than 300mM and a bath temperature of less than 30°C were indispensable deposition conditions for obtaining a-Fe-B films with a B concentration exceeding 20at%. Furthermore, a-Fe-B films with low coercivity of less than 3.6 Oe and a large magnetostrictive constant of 26×10-6, which are thus comparable to sputtered a-Fe-B films, can be obtained by using a combined complex agent consisting of KNaC4H4O6 and (NH4)2SO4. ESCA measurements showed that about 80at% boron chemically bound with iron, but about 20at% boron combined with oxygen, because the electrodeposited films contain oxygen and carbon.
Electrodeposition is a promising candidate for the preparation of magnetic nanostructures. Multilayered fcc Co/Pt and CoNi/Pt nanostructures grown on a Pt (111) or Cu (111) single-crystal substrate by electrodeposition under potential control respectively exhibit remanent perpendicular magnetization and large coercivity, which depend on the deposition overpotential and hence the multilayer growth mechanism. Giant magnetoresistance and oscillatory interlayer coupling have been observed ire a fcc (111) textured Co/Cu multilayered nanostructure. Moreover, a large saturation magnetoresistance of more than 20% has been achieved at room temperature for a heterogeneous Co-Cu alloy, which consists of ultrafine fcc Co-rich clusters in a nonmagnetic Cu matrix.