Showing papers on "Electroplating published in 1991"

The Behavior of Zinc Electrode in Alkaline Electrolytes II . A Kinetic Analysis of Anodic Dissolution

Abstract: A model for the kinetics of active zinc dissolution is developed taking into account the presence of an interfacial layer. From electrode impedance spectroscopy, it is shown that the metal dissolution takes place essentially at the base of pores in a conductive layer of oxidation products which is progressively degraded by the anodic current

The electrochemistry of Magnéli phase titanium oxide ceramic electrodes Part I. The deposition and properties of metal coatings

Abstract: The electrodeposition of copper, gold, nickel, palladium and platinum onto Ebonex® ceramic cathodes has been studied It is demonstrated that good quality deposits may be obtained and that the kinetics of the deposition and dissolution of metals are similar at Ebonex® to other common substrates (for example, Pt, C) In addition, the kinetics of some simple redox couples at coated and bare Ebonex® ceramic electrodes are compared; it is confirmed that such electron transfer reactions are very slow on the bare Ebonex® ceramic but when the surface is coated with a metal, the kinetics are similar to those on the bulk metal

Electroplated solder joints for flip-chip applications

Abstract: A step-by-step description of a solder electroplating process for flip-chip applications is provided. The necessity of phasing Cr and Cu in the under-bump metallurgy (UBM), which also functions as the current path during plating, is verified by a scanning-electron-microscope (SEM) study of the intermetallics in the reflowed solder joints. Characteristics of the SnPb solder plating bath are presented, and key issues on designing and operating manufacture scale cells are identified. Mathematical modeling of the plating process confirms the capability of the plating process to produce solder bumps of uniform volume and solder composition. Feasibility of the electroplated solder bumping process is demonstrated on dice with an area array of pads of a approximately 0.005-in diameter on a 0.010-in pitch. Data on preliminary mechanical testing conducting to evaluate the integrity of the solder joints are presented. >

Porous electrode with enhanced reactive surface

Abstract: A body implantable electrode includes a platinum wire or filament compressed and bundled into a serpentine configuration and retained within a platinum screen, thus to form a highly porous electrode. The electrode body is then surface treated by vapor deposition or vapor deposition in combination with electroplating, to provide an adhesion layer, a texturizing layer, and one or more catalytic cover layers. The texturizing layer, which can be titanium, carbon black or aluminum, is formed with multiple nodules and depressions which substantially increase the reactive surface area of the electrode. The catalytic layer can be platinum, platinum-black or platinum followed by a layer of carbon. The combination of macro porosity and micro texture provides an electrode that promotes tissue ingrowth after implant and maintains a low chronic stimulation threshold due to its large reactive surface area in proportion to its geometric size.

Process and apparatus for control of electroplating bath composition

Abstract: A process and apparatus for electroplating metals in which the metal salt concentration within the electroplating bath is reduced by providing an insoluble anode assembly in the bath. The insoluble anode assembly includes an enclosure which defines a compartment around an insoluble anode and which is formed at least in part by an anion exchange membrane. The primary reaction at the insoluble anode during electroplating is electrolysis of water to produce predominantly oxygen and hydrogen ions. The flow of current through the insoluble anode assembly causes anions in the plating solution to travel through the anion membrane into the compartment, resulting in an increase in acid concentration within the compartment. Accumulated acid is periodically flushed from the compartment.

Method for analyzing organic additives in an electroplating bath

Abstract: A direct method of analyzing brighteners and levelers used in metal electroplating baths. The method is based on the differential adsorption of these additives on a working electrode during a sequence of steps prior to and during metal plating. The sensitivity of the method allows for the determination of both brightener and leveler in the same sample without cyclic processing.

Process for preparing a nonconductive substrate for electroplating

Abstract: Described herein is an improved process for electroplating a conductive metal layer to the surface of a nonconductive material comprising pretreating the material with a carbon black dispersion followed by a graphite dispersion before the electroplating step.

Process for surface treating titanium-containing metallic material

Abstract: A titanium-containing metallic material having a high heat-resistant and abrasion resistant surface is produced by (A) cleaning a titanium-containing metallic material, (B) first plating the cleaned surface of the metallic material with Cu or Ni by a strike or flash plating method, (C) second plating the first plated surface of the Ti-containing material with Ni, Ni-P alloy or a composite material comprising a Ni-P alloy matrix and fine ceramic particles dispersed in the matrix by an electroplating method, (D) non-oxidatively heat treating the second plated Ti-containing material at 450° C. or more for one hour or more, (E) surface activating the second plated surface of the Ti-containing material, (F) coating the activated surface of the Ti-containing material with a heat and abrasion resistant coating layer comprising a matrix consisting of a Ni-P alloy or cobalt and fine ceramic particles dispersed in the matrix, and optionally, (G) surface-roughening the heat and abrasion-resistant coating layer surface of the Ti-containing material to a RZ of 1.0 to 10.0 μm, and (H) coating the roughened surface of the Ti-containing material with a solid lubricant coating layer comprising at least one member selected from MoS2, graphite, boron nitride and F-containing polymer resin.

Determination of Partial Currents for CuNi and CuCo Electrodeposition Using Rotating Ring‐Disk Electrodes

Abstract: An electrochemical stripping technique has been developed for the analysis of Cu alloys with iron‐group metals (particularly Ni). The alloy is plated on the disk of a rotating ring‐disk electrode. The electrode is transferred after plating to an solution and stripped potentiodynamically. The Ni and Cu dissolve in the +2 and +1 oxidation states, respectively; the Cu(I) can be detected by oxidation to Cu(II) at the ring. From the ring and disk charges during stripping and the disk plating charge, the plating efficiency and the deposit composition can be calculated. The validity of the method was confirmed by inductively coupled plasma analysis. The technique has been used to examine the interrelationship of composition and plating conditions, varying the solution composition, rate of mass transfer, current density, and ambient atmosphere. A comparison of and alloys plated under the same conditions reveals that the Co alloys have a lower Cu content and are plated with higher current efficiency.

Manufacture of semiconductor device

Abstract: PURPOSE:To prevent a resist from peeling in an electroplating formed by a plating of a plated layer even if the thick plated layer is selectively plated on a first metal thin film by a method wherein a second metal thin film for improving an adhesion to the resist is formed on the first metal thin film which is used as a plating base. CONSTITUTION:A metal thin film 13 for improving an adhesion to a resist is formed on a metal film 12, which is used for making a current flow and is used as a plating base. Therefore, even if the width and thickness of the resist 14 for air bridge formation use are formed in the same degree and a thick plated layer 16 is selectively plated on the film 12, the resist is prevented from peeling in an electroplating formed by a plating of the plated layer by the film 13. Moreover, as the film 13 for adhesion improvement use in the parts of opening parts 15 is etched away by anisotropic etching before the layer 16 is plated, the generation of an undercut is prevented and even if an air bridge pattern is such a pattern as a plurality of pieces of air bridges 10 are provided side by side at fine intervals, there is no possibility of the generation of a short-circuit between the adjacent fellow air bridges 10 at the time of the electroplating.

Zinc-nickel coatings: Relationship between additives and deposit properties

Abstract: The electroplating of zinc-nickel alloys from a chloride bath containing two brighteners (a phenolic derivative and an unsaturated aromatic compound) and a levelling agent (an aromatic carboxylate) has been studied under different plating conditions. The composition and morphology of the alloys depended on the concentration of all the additives and also on the temperature. As a general effect, these additives smooth the deposit and refine the grain size. By means of scanning electron microscopy, it was possible to classify the deposit morphologies according to the type and concentration of the additives. The resistance of the alloys to corrosion was studied by means of a neutral salt-spray test.

Directionality of thermal ink jet transducers by front face metalization

Abstract: A thermal ink jet printhead has an outer, metallic hydrophobic coating on its front face to repel ink. Eliminating the accumulation of ink at the nozzles of the printhead allows an ink droplet to be accurately ejected and ensures the directionality of the ejected ink droplet onto the printing medium. The outer coating is formed of a metal selected from the group of noble metals, including gold, platinum, palladium, silver, rhodium and ruthenium. An adhesion layer is preferably deposited between the front face of the printhead and the outer ink-repellent coating. The metallic coating is preferably applied by electroplating, wet electroless plating, evaporation, sputtering, ion plating, CVD or plasma CVD.

Solder bump transfer method

Abstract: A method for forming a plurality of solder bumps on an electronic component substrate utilizes a transfer plate to electrodeposit solder deposits and subsequently reflow the deposits onto the substrate. The plate comprises discrete pad electrodes formed of a ceramic material that is suitably electrically conductive to permit electroplating of the solder alloy, but is not wet by the molten solder to permit reflow onto the substrate. A preferred electrode material is an indium oxide compound. The solder deposits are plated onto the electrodes, and the transfer plate is superposed on the substrate such that the bumps rest upon bond pads on the substrate. The assembly is heated and cooled to melt and resolidify the solder alloy, whereupon the solder bonds to the substrate pads to form the bumps.

Process for reflow bonding of bumps in IC devices

Abstract: In a semiconductor device tape assembly bonding process the fingers of a copper tape are reflow soldered to metal bumps located on the semiconductor device. First, the semiconductor wafer is covered with a conductive film composed of thin layers of aluminum, nickel-vanadium alloy and gold. The bumps are then created by electroplating gold through openings in a photoresist mask. The gold bumps are overcoated with a contolled thickness tin layer and the tin is overcoated with a thin gold anticorrosion layer. The copper assembly tape is coated with a thin gold layer and are lightly pressed against the bumps by means of a thermode. The thermode is quickly heated to a temperature well above the gold-tin eutectic melting temperature and then rapidly cooled. The tin layer on the bump will combine with the adjacent gold to form a liquid phase eutectic which will form and contact both the copper finger and the gold bump. Upon cooling the eutectic melt will solder the finger to the bump. Since all of the tin is combined with the gold there is no metallic tin left in the system and the problems of tin whiskers and tin electromigration are avoided.

Zinc-based microfuse

Abstract: A zinc-based temporary electrical connection (e.g., a microfuse) useful in electroplating isolated conductor (i.e., copper) structures and copper/polyimide high-density interconnect structures are disclosed. The microfuse includes a zinc conductor layer, and in some embodiments, additional silicon adhesion and silicon protection layers. The microfuse is conductive, and therefore useful in an electroplating process, until it is treated (e.g., heated to about 400° C. for one hour), to convert it into an insulator due to zinc oxidation, and remains in this state.

The hydrogen evolution reaction in an acid medium on nickel electrodeposited with PMo12O 40 3− or MoO 4 2−

Abstract: Nickel was electrodeposited from dilute aqueous solutions of nickel chloride, containing MoO42− or PMo12O403− ions. It was shown that improvement in the overpotential (η) and in the exchange current density (i0) of the electrodes depends on the composition of the deposition bath. The h.e.r. electrocatalytic activity of the electrodeposits was then analysed and related to their chemical composition. The results show that some extremely active electrocatalysts are produced when combinations of nickel-molybdenum (Ni−Mo) are formed. The influence of the MoO42− or PMo12O403− concentration in the electrode deposition electrolyte on the electrocatalytic properties of these deposits for the hydrogen evolution reaction (h.e.r.) was investigated. The effects of the deposition current density on the electrocatalytic properties of the electrodes were also studied. The best electrocatalytic properties for the h.e.r. were obtained with electrodes electrodeposited with 2 g dm−3 of MoO42− or PMo12O403−. The kinetic parameters for the h.e.r. in H2SO4 1 M were deduced for temperatures ranging from 298 to 378 K.

The effect of plating variables on zinc-nickel alloy electrodeposition

Abstract: Acid chloride based solutions, pH approximately 5.5, were used for the deposition of zinc-nickel alloy coatings. The initial objective of this research project was to study the effects of variations in the nickel content of the plating solution and current density on the deposit composition. Subsequently the effects of variations in solution temperature, pH and agitation on deposit composition and cathode current density were evaluated for the solution containing 15 g/l nickel. The influence of plating conditions on appearance, microhardness and macro throwing power were also studied

Method for partially plating plastic molded body

Abstract: PURPOSE:To form plating layers on a plastic molded body by partial electroplating without lowering production efficiency. CONSTITUTION:A plastic molded body 10 is subjected to a surface roughening process and an activating process, palladium is stuck to the entire peripheral surface of the molded body 10 and electroless Ni plating is carried out to form an Ni plating layer 4. Parts 2 for decoration such as initials are removed from the layer 4 with laser beams to expose the surface of the molded body 10. A Cu plating layer 5, an Ni plating layer 6 and an Au plating layer 7 are then formed on the molded body 10 by electroplating. These layers do not grow on the parts 2.

Electroplating method and apparatus

Abstract: The present invention relates to a method of electroplating in which the electroplating bath is treated by the direct injection of electromagnetic radiation. Most preferably, the electromagnetic radiation is within the radio frequency range and is injected through a metal conductor directly in contact with the bath. Such treatment increases the speed of electroplating as well as the quality of the plated product. The invention is applicable to the plating of zinc, chrome, nickel, precious metals and the like.

An electrochemical mass transport sensor to study agitation in electroplating processes

Abstract: A sensor based on limiting current density characteristics of a wire tip electrode has been shown to be capable of measuring local variations of agitation and its effect on coating thickness variations during electrodeposition. The effectiveness of agitation is expressed as an enhancement factor.

Production of complex cavities inside castings or semi solid forms

Abstract: The production of complex cavities inside castings or semi solid forms is effected by forming a core pattern (10) of a low melting point metal in order to provide a rigid metal core pattern (10). The pattern (10) is then nickel coated using either electroplating or electroless nickel plating. The metal core pattern (10) is melted out of the nickel plating to provide a nickel liner core (16). The nickel liner core (16) is placed within a mold or die cavity, and molten metal introduced into the cavity in order to provide a casting or form (30). The casting or form (30) is removed from the cavity and includes therein a plurality of passageways (20) each of which is defined and surrounded by a corrosion resistent nickel liner surface (22).