Showing papers on "Electroplating published in 1989"

Stacked solid via formation in integrated circuit systems

Abstract: A method of forming solid copper vias in a dielectric layer permits stacked up vias in a multi-layer multi-chip carrier. An conducting layer is deposited over a substrate and lines of a first interconnect layer formed on the substrate. An aperture formed in a photoresist layer over said lines is filled with copper by electroplating to form a solid via. The via can be polished until its top is flat. Using a photoresist mask, the conductive layer used for electroplating is removed between the lines. A dielectric layer is then formed over the lines and via. A bulge in the dielectric over the via is removed by etching through an aperture defined in a photoresist layer, which is then stripped. A second interconnect layer can be formed on the resulting structure. The foregoing steps can be iterated to build a multi-layer structure with stacked up vias.

Method of electroplating a precious metal on a semiconductor device, integrated circuit or the like

Abstract: A method for electroplating a layer of a precious metal, copper or aluminum on a surface of a semiconductor device, an integrated circuit, or the like employs an electrolytic cell in which the cathode comprises a semiconductor device, an integrated circuit device, or the like, having a surface for receiving the precious metal layer. The surface is oriented in a position normal to a vector representing the acceleration of gravity and facing the anode of the cell. An electroplating direct current on the order of about 0.1 milliamp/cm2 is employed while superimposing a time varying electromagnetic field in the range of about 1 to about 100 megahertz on the direct current. The electroplating current and the electromagnetic field are employed in the absence of convection, i.e. stirring, in the electrolyte. The product produced by the described method comprises a smooth, evenly distributed layer of the precious metal having a microstructure that is characteristic of single crystals.

Metallized plastics 1 : fundamental and applied aspects

Abstract: Metallization Techniques and Properties of Metal Deposits.- Laser Stimulated Chemical Vapor Deposition of Metals on Polyimides.- Graded Metallization of Nonconducting Substrates by Glow Discharge Plasma Polymerization.- Metallization of Plastics with Resistance Heated Sources.- High Rate Reactive Sputtering onto Flexible Polymer Sheet.- UV Laser-Induced Metallization of Polyimide from Electroplating Solution.- Simple Metal-on-Plastics Patterning by Pulsed Electron Beam in Soft Vacuum.- Optical Performance and Durability of Silvered Polymer Mirrors.- Deposition of Adherent, Thick Copper Coatings on Glass.- Dependence of Stress on Deposition Conditions for Sputtered Copper Films onto Flexible Polyimide Substrates.- Metal Interlayers in Polymer Films: A Survey of Deposition Processes, Morphology, Patterning Methods and Physical Properties.- Spectroscopic Investigation of Interfacial Interactions.- Surface Spectroscopic Techniques Applied to Metallized Plastics.- A Static SIMS Study of Interfaces between Evaporated Metal Films and Polyimides.- XPS and HREELS Study of the Aluminum/Poly(ethylene terephthalate) Interface and the Influence of the Polymer Surface Pretreatment on Adhesion.- Interfacial Chemistry of Metal Films on Polymers: Diffusion, Oxidation, Trace Components Studied by XPS, ISS, and SIMS.- Surface Modification and Adhesion Aspects.- Characterization of Surface Modifications during Metallization of Polyetherimide.- Effect of Plasma Treatment and Ion-Plating on Adhesion of Metallized Polyimide and Poly(ethylene terephthalate).- Adhesion of Chromium, Nickel, and Copper to Polymers Containing Basic Functional Groups.- Adhesion and Deformation Behavior of Thin Metal Films on Polyimide.

In Situ Scanning Tunneling Microscopy of Polycrystalline Platinum Electrodes under Potential Control Copper Electrodeposition and Pyrrole Electropolymerization

Abstract: The surface changes of Pt electrodes immersed in solution under potential control were studied by scanning tunneling microscopy. Various structures were observed on a polished, flame-annealed-quenched polycrystalline electrode. Extended cycling of the electrode in 1M H2SO4 between the regions where an adsorbed oxide film forms and is removed causes significant roughening of the electrode surface. The electrodeposition of copper on polycrystalline Pt and of polypyrrole on a Pt film on mica was also investigated. The scanning tunneling microscope (STM) allows very high resolution (atomic or near-atomic) examination of the surfaces of conductive or semiconductive substrates (1, 2). Although originally mainly applied to samples in a vacuum or a gaseous environment, this technique has been used to investigate various substrates immersed in aqueous and nonaqueous solutions (3-9). We have further demonstrated the in situ study of anodic dissolution of nickel electrodes in sulfuric acid solution under external polarization conditions and open-circuit corrosion of stainless steel in aqueous chloride media (10).

Pulse plating effects in nickel electrodeposition

Abstract: The effects of pulse plating on the mechanical properties and internal stresses of nickel deposits were investigated. The yield and tensile strengths increased as a result of pulse plating especially at high peak current densities because of grain refinement. A reduction in the tensile internal stresses due to pulse plating was greatest at high current densities. This was attributed to relaxation during the off-time and to larger amounts of codeposited hydrogen, which also resulted in a reduction in the tensile stresses with increasing pulse frequency.

New through-hole plated printed circuit board and process for manufacturing same

Abstract: A process is described for manufacturing through-hole plated single-layer or multi-layer printed circuit boards based on a polymeric substrate material or on a ceramic material provided optionally on both sides with at least one electroconductive layer by electroplating or electroless plating with a metal layer also on those surfaces which have not been coated with a conductive metal layer, said process being characterized in that a) the surfaces of the substrate are pre-treated in a solution having oxidizing activity, b) after removal of the residual solution by rinsing, the substrate is introduced into a solution which contains at least one monomer, and more specifically pyrrole, furane, thiophene or derivative(s) thereof, which in a polymeric or copolymeric form is electrically conductive, c) the substrate is then transferred into an acidic solution whereby an electrically conductive polymeric layer, more specifically of polymerized or copolymerized pyrrole, furane, thiophene or derivative(s) thereof, whereupon, if desired or required, any residual solution is removed by rinsing, and the galvanic or electroless metallization is carried out.

Laser-induced metal deposition on semiconductors from liquid electrolytes

Abstract: Maskless deposition of gold and copper from electrolyte solutions onto n‐doped semiconductors (GaAs, Si) is investigated. The metal deposits are found to have lateral dimensions of about 1 μm and are in barrier contact with the semiconductor. The proposed deposition mechanism is governed by the electric fields resulting from the Dember effect, the p‐n junction, and the thermal emf.

Belt plating method and apparatus

Abstract: A thin plastic elongate mask is disclosed for use in continuously electroplating an elongate substrate. Apparatus is disclosed wherein the mask is mated with the substrate, is passed through an electroplating zone, supported by support belts, such that only those areas of elongate substrate covered by plating cavities in the mask are plated. The mask may be located on the substrate by means of corresponding location features positioned on the elongate substrate and the mask. A method of continuously electroplating an elongate substrate using a thin plastic elongate mask is further disclosed.

Palladium alloy plating process

Abstract: A process is described for electroplating palladium and palladium alloys. The process involves the use of an alkyl hydroxyamine as complexing agent and is particularly good for palladium alloys such as palladium-nickel and palladium-cobalt.

Self-aligned process for fabrication of interconnect structures in semiconductor applications

Abstract: A method for fabricating conductors in dielectric trenches in a self-aligned manner. Interconnect modules with a high conductor density are achieved by using a copper-polyimide system as a versatile packaging approach. A photosensitive polyimide is applied to a substrate and lithographically patterned to form polyimide steps having a characteristic positive slope, between which are defined trenches in which the substrate is exposed. A thin electroplating seed layer is deposited over the polyimide steps and the substrate. Copper is electroplated into trenches, but does not plate onto the tops of the polyimide steps, since the electroplating seed layer at that location is not electrically connected to the electroplating seed layer in the bottom of the trenches. The electroplating seed layer on top of the polyimide steps is then removed by chemical etching, plasma machining, or ion-milling. A planar structure is eventually obtained without the use of multiple coatings of polyimide layers or any additional masking layers or lift-off layers.

Electrodeposition of chromium from Cr (III) electrolytes in the presence of formic acid

Abstract: Chromium coatings deposited from sulphate, chloride and perchlorate electrolytes based on the [Cr(H2O)4(HCOO)]2+ complex ion were investigated. The current efficiency reached 30% in the case of chloride electrolyte for various current densities in the range 4–10 A dm-2 depending on pH. Such a large current efficiency is due to the catalytic effect of the chloride ions on the electroreduction of the chromium complex to metallic chromium. Deposition of chromium from sulphate electrolyte took place with a current efficiency of 16% which rose for higher pH and lower current densities. Semi-bright and bright coatings with thickness of approximately 10μm of good adhesion to a copper electrode were deposited from chloride and sulphate electrolytes.

Electrodeposition on Cuprate‐Based Superconductors in Nonaqueous Media

Abstract: Electrodeposition of metallic protection layers on the Ba/sub 2/YCu/sub 3/O/sub 7/ high -T/sub c/ superconductor has been carried out in non-aqueous electrolytes based on the organic solvents acetonitrile, methanol, and propylene carbonate. By lowering the reactivity of the solvent to the strongly oxidized superconductor, the range of potential accessible to cathodic reactions can be extended. In acetonitrile, films of silver, copper, lead, and tin can be deposited, whereas in water it is difficult to achieve more than silver deposits because of the ready reduction of the cuprate compound. Electrochemical techniques with rotating disk and ring-disk electrodes in the nonaqueous electrolytes gave clear voltammetric evidence for the deposition of the metals, their anodic stripping from the substrate, and the ability to cycle the superconductor between plated and uncovered states. Optical microscopy, scanning electron micrographs, and energy dispersive x-ray measurements were used to support the conclusion of high-coverage, microcrystalline metal contacting layers being achieved on the superconductor substrate.

Structure, composition, and surface topography of cadmium telluride films fabricated by a new nonaqueous electroplating technique

Abstract: A new electroplating technique for growing cadmium telluride films in a nonaqueous medium is reported. The influence of the deposition conditions on the structure, stoichiometry, and surface topography of the CdTe films has been discussed in light of the x‐ray diffraction analysis, x‐ray photoelectron spectroscopy, and scanning electron microscopy studies. Higher bath temperatures have been found to favor larger grain growth with a certain amount of orientation. The CdTe formation is not favored at temperatures <130 °C. The compositional analysis using x‐ray photoelectron spectroscopy indicated that the films deposited under galvanostatic conditions are generally richer in cadmium. Nearly stoichiometric films can be deposited under potentiostatic conditions at a deposition potential of −0.8 V (with respect to Pt neutral electrodes). A uniform and regular growth of CdTe films with no sign of cracking was also observed in the surface investigations by a scanning electron microscope.

Electroplating of fine particles with metal

Abstract: Disclosed herein suspension electroplating of fine particles with metal. An electroplating operatively equipped with a cathode and anode is charged with a a metallic ion-containing electrolyte and particles to be electroplated. The particles have a size of from 0.1 to 10 µm. At least a part of the surface of each particle is conductive. Such a stationary circulating flow of a suspension of the particles in the electrolyte is formed in the bath that the particles are maintained in the suspended condition; the suspension is circulated substantially without coming in contact with the anode; the particles may have a chance of colliding with substantially all surface areas of the working surface of the cathode, and are repeatedly brought in collision with the cathode at a velocity with a normal component of from 0.6 to 6.0 m/min.; and a particle concentration of the suspension at the time of collision is from 30 to 55 % by volume. When such a stationary flow has been formed, a current for electroplating is caused to pass, whereupon deposition of metal on the particles proceeds without deposition of the particles and metal on the cathode.

Electroplating composition and process

Abstract: A composition for electroplating copper onto a conductive surface comprising a solution soluble copper salt and an acid electrolyte, said copper salt being present in a concentration of from about 1 to 10 grams per liter of solution and said acid being present in a concentration whereby the acid to copper ratio preferably varies between about 30 to 1 and 50 to 1. The composition is especially useful for the plating of walls of cylindrical openings having a ratio of height to diameter of at least 10 to 1 and a length of at least 0.100 inches.

Solid phase plating method

Abstract: PURPOSE:To easily perform fine solid phase plating without using plating liquid with high positional precision without using a plating mask by allowing a solid electrolyte connected to an anode to abut against a body to be plated which is connected to a cathode and impressing voltage between then. CONSTITUTION:A solid electrolyte 3 consisting of e.g. silver ion conductive glass is allowed to abut against a body 1 to be plated such as metal, ceramic and plastic with about 500g/cm load and DC voltage of single-phase full wave is impressed. When current starts to be allowed to flow, silver ion is implanted from an anode rod made of pure silver being an anode 4 and allowed to migrate in the electrolyte 3 and discharged on the surface of a copper plate being the body 1 to be plated and deposited as metallic silver. In this case, when 10V impression voltage and 1 A/dm current density are impressed, film formation velocity of silver plating is regulated to value of 0.01X175=1.75mum/sec. This film formation velocity is 50-100 times of conventional electroplating and 2+5 times of a recent high-speed jet type aq. soln. plating method.

Studies of copper deposition for high aspect ratio printed circuit boards

Abstract: SummaryThe effects of temperature, current density, electrolyte composition and additive content on the electrodeposition of copper from acidic sulphate solutions have been investigated. Wagner numbers (Wa) were calculated from fundamental electrochemical studies at a rotating disc electrode. These were used to predict the throwing power of the system and to optimise plating conditions. Correlation betwen plating tests carried out on boards of 8:7 aspect ratio and fundamental results was excellent. Current density and solution conductivity were found to be the major influences on deposit uniformity and optimum conditions to obtain a 1:1 surface to hole ratio were established.

Method of copper-nickel-chromium bright electroplating which provides excellent corrosion resistance and plating film obtained by the method

Abstract: This invention is directed to a method of copper-nickel-chromium bright electroplating which provides excellent corrosion resistance, character­ized in that said bright electroplating film comprising a copper and a nickel plating layers formed on a basis material or a nickel plating layer directly formed on a basis material, a microporous layer of a thickness of 0.2-2µm codeposited on said nickel plating layer by adding calcium salt and titanium oxide to Watts bath type of nickel plating bath, chromium plating layer with a thickness of 0.01-0.25µm on said microporous layer and a chromium plating surface with micropores of 20000-500000/cm², and is directed to the plating films obtained by the method.

Cyanide-free copper plating process

Abstract: A process for electroplating copper from an aqueous alkaline non-cyanide bath has improved resistance to degradation. At least a portion of the plating bath is subjected to electrolysis by an insoluble anode to which the current is controlled independently from the current to the soluble copper anode in order to reduce the level of bath impurities and maintain the quality of the deposit.

Selective electroplating apparatus and method of using same

Abstract: An electroplating apparatus for rapidly depositing a metal onto a selected surface of a workpiece, which apparatus comprises an anode having an active surface with a selected shape to combine with the selected surface of the workpiece to define an elongated gap of at least about 0.050 inches, means for supporting this anode in a fixed position to define the elongated gap; solution circulating means for forcing an electroplating solution with metal cations through the gap in a generally closed path at a velocity to exchange electroplating solution in the gap at a rate of at least 25 times per minute; and, means for applying current flow between the selected workpiece surface and the active surface of the anode through the gap at a current density in excess of 2.0 amperes/in 2 . The invention also involves the method of using this apparatus to rapidly deposit metal, such as nickel, onto the inner cylindrical surface of a bore on a complex part such as an aircraft landing gear forging.

Process for electroplating electroactive polymers and articles derived therefrom

Abstract: The invention consists of a process for pulse electroplating electroactive polymer substrates at potentials sufficient to cause reduction of the substrates. The inventive process can be used to make polymer-metal composites having one or more metal films. More specifically, it can be used to electroplate polyimide substrates with gold, or to electroplate gold over a copper plated polyimide substrate. These inventive composites exhibit improved polymer-metal adhesion when they are exposed to elevated temperatures and humidities, i.e., 85° C. and 85% R.H.