Showing papers on "Electroplating published in 1997"

Plated copper interconnect structure

Abstract: A high conductivity interconnect structure is formed by electroplating or electroless plating of Cu or a Cu-base alloy on a seed layer comprising an alloy of a catalytically active metal, such as Cu, and a refractory metal, such as Ta. The seed layer also functions as a barrier/adhesion layer for the subsequently plated Cu or Cu-base alloy. Another embodiment comprises initially depositing a refractory metal barrier layer before depositing the seed layer.

Pulse electroplating copper or copper alloys

Abstract: High aspect ratio openings in excess of 3, such as trenches, via holes or contact holes, in a dielectric layer are voidlessly filled employing a pulse or forward-reverse pulse electroplating technique to deposit copper or a copper-base alloy. A leveling agent is incorporated in the electroplating composition to ensure that the opening is filled substantially sequentially from the bottom upwardly.

Electroplating system with shields for varying thickness profile of deposited layer

Abstract: An electroplating system includes shield(s) to control the thickness profile of a metal electrodeposited onto a substrate. The shield(s) are positioned between the anode and the cathode in a standard electroplating apparatus with a device for rotating the plating surface. The cathode is rotated so that the shield(s) in conjunction with the rotation of the cathode selectively alters or modulates a time average of the electric field characteristics between the anode and the cathode. The modulated electric field is used to control the electrodeposition rate at selected area(s) of the plating surface of the cathode, thereby causing the metal deposited on the cathode to have a modified thickness profile.

Process for depositing a layer of material on a substrate

Abstract: An electroplating system ( 30 ) and process makes electrical current density across a semiconductor device substrate ( 20 ) surface more uniform during plating to allow for a more uniform or tailored deposition of a conductive material. The electrical current density modifiers ( 364 and 37 ) reduce the electrical current density near the edge of the substrate ( 20 ). By reducing the current density near the edge of the substrate ( 20 ), the plating becomes more uniform or can be tailored so that slightly more material is plated near the center of the substrate ( 20 ). The system can also be modified so that the material that plates on electrical current density modifier portions ( 364 ) of structures ( 36 ) can be removed without having to disassemble any portion of the head ( 35 ) or otherwise remove the structures ( 36 ) from the system. This in-situ cleaning reduces the amount of equipment downtime, increases equipment lifetime, and reduces particle counts.

Electrodeposition of particle-strengthened nickel films

Abstract: Dispersion-strengthened nickel films were obtained by co-deposition of Al 2 O 3 particles with a mean particle diameter of 14 nm followed by heat treatment at 850 °C. The co-deposition was achieved by addition of Al 2 O 3 powders in a typical Watts bath before electroplating of nickel on copper substrates. The Ni films are analyzed by light and transmission electron microscopy and by measurement of the coercivity and the microhardness. The particle-strengthened Ni films show a remarkable improvement of hardness due to grain stabilization and dispersion hardening of the nickel grains by alumina nanoparticles as observed by structural investigations of the samples. Reinforcement of electrodeposited nickel films by nanosized alumina particles is a simple process producing wear-resistant coatings.

Oxidation behavior of surface-modified titanium for titanium-ceramic restorations

Abstract: Statement of problem. Titanium-ceramic bonding is an unsolved problem for the current use of titanium-ceramic restorations. Purpose. The purpose of the study was to characterize oxide formation on titanium surfaces at porcelain sintering temperatures and to determine the effect of chromium coating methods on titanium oxide formation. Material and methods. Sputter coating and electroplating methods of chromium application were compared and combined. Results. Porous, weak titanium oxide formation on uncoated samples was demonstrated at porcelain sintering temperatures. Groups with chromium coating as an oxygen diffusion barrier exhibited lower oxidation rates, except samples coated by sputtering alone. Temperature effect was found to have the greatest significance on titanium oxidation rate. The overall lowest oxidation rate was located in the group that had chromium coating by the combined coating method and was oxidized at 750° C. Conclusion. The electroplating method requires further investigation and development so that a uniform chromium layer can be deposited on titanium. (J Prosthet Dent 1997;77:423-34.)

Method for reducing oxidation of electroplating chamber contacts and improving uniform electroplating of a substrate

Abstract: A method for electroplating a silicon substrate in manufacturing a semiconductive device is provided. Electroplating process chamber contacts or fingers used in positioning a silicon substrate or wafer during an electroplating process are plated with a metal layer to prevent oxidation of the contacts. Oxidation of the contacts may result in increased and varying resistance of the contacts and thus nonuniform plating of the silicon wafer and possibly even deplating of a seed layer. A 20 mA/cm2 current is applied to the contacts which are immersed in an electrolyte solution before loading a silicon wafer. A silicon wafer is then loaded into the electroplating process chamber containing the electrolyte solution. The preplating of the contacts enables the formation of a uniform metal layer on the silicon substrate. Additionally, voltage then may be applied to the contacts after unloading the silicon wafer to reduce oxidation. This electroplating method reduces expensive maintenance time in replacing or cleaning electroplating chamber contacts. The method also does not require expensive and complex electronics to monitor and supply current to the contacts.

Process for integrated circuit wiring

Abstract: Metal wiring is provided in an integrated circuit by sputter coating onto a semiconductor substrate a copper seed layer; depositing and patterning a photoresist; electroplating or electrolessly plating a metal within the openings of the photoresist; stripping the remaining photoresist; and etching the copper seed layer with an etchant that preferentially etches the copper seed layer at a rate higher than that for the electroplated or electrolessly plated metal.

Microcontact printing and electroplating on curved substrates: Production of free‐standing three‐dimensional metallic microstructures

Abstract: Microelectromechanical systems (MEMS) often require three-dimensional parts with micrometer-sized features. Currently, mechanical or laser micromachining tools,['] or multistep planar lithographic schemes are used to construct these parts. In this communication, we describe a convenient means for fabricating three-dimensional microstruc-tures. The method begins with the generation of thin patterns of metal produced by microcontact printing (pCP)[*I on curved substrates. Electrodeposition increases the thickness and rigidity of these structures,[31 and removal of the substrate results in freestanding, three-dimensional objects. We demonstrate this method through the fabrication of structures whose dimensions and mechanical properties are appropriate for micro-coil springs and medical devices known as coronary stents. Stents are small expandable tubular structures that are used to hold open anatomical structures and they are increasingly used to prevent blood vessels from collapsing after balloon angi~plasty.~~] Figure 1 summarizes the sequence of fabrication for mi-crostructures with the geometries of micro-coil springs and coronary stents. We first coated all sides of glass cylinders (Kimble Products, KIMAX-51, outer diameter-1.60 mm for the stents, and Polymicro Technologies, outer diameter-134 pm for the micro-coil springs) with titanium (-25 A) and silver (-500 A) using an electron beam evaporator and a system of mechanical rotation stages.[51 pCP was then used to pattern the surface of these cylinders with a self-assembled monolayer of he~adecanethiolate.[".~~ In pCP, contact of an 'inked' elastomeric stamp with a substrate transfers ink from the stamp to the substrate. We printed the entire outer surface of our cylinders by rolling them over a stamp inked with a solution of hexadecanethiol. The stamping process was controlled with an arrangement of precision rotation and translation stages.[71 evaporate titanium (25& adhesion promoter) and silver (500A) 1 microcontact print; etch unprotected silver and titanium 1 make electrical contact; electroplate silver 1 dissolve capillary in HF and release structure 1 1-3 cm Fig. 1. Scheme for fabricating a stent using Microcontact Printing (pCP). Glass cylinders were coated with titanium (-25 A) and silver (-500 A) using an electron beam evaporator. pCP of hexadecanethiol onto the cylinder created a monolayer resist with the geometry of the stamp. A selective wet chemical etch removed silver not protected by the monolayer. Immersion of the patterned cylinder in 1 % H F removed exposed titanium. Electrodeposi-tion of silver increased the thickness of the silver by a few hundred microns. Removal of the glass substrate using concentrated HF produced a rigid. free-standing structure made of silver. For …

Continuous vertical plating system and method of plating

Abstract: An electroplating apparatus comprising: an electroplating tank assembly for receiving an electroplating solution; transfer structure for transferring a substrate to be electroplated along a transfer passage within the electroplating tank assembly; at least one pair of sparger assemblies for dispersing the electroplating solution in the direction of the substrate; at least one pair of anode baskets for containing anode material; electricity feeding circuitry for feeding electricity to the anode material contained in the at least one pair of anode baskets; and at least one pair of anode shield assemblies positioned to direct a current flux toward the substrate to provide for a uniform distribution of plating material thereon.

Fabrication of Nickel Microbump on Aluminum using Electroless Nickel Plating

Abstract: Fabrication of nickel microbumps on an aluminum electrode using a nickel displacement and a direct nickel plating process was investigated. Electroless nickel plating reaction with hypophosphite as a reducing agent was not initiated on the aluminum substrate, because aluminum does not have catalytic action on the oxidation of hypophosphite. Accordingly, nickel was initially deposited on the aluminum using nickel displacement plating for the initiation of the electroless plating. Nickel bumps on the aluminum electrode were fabricated by treatment of the nickel displacement plating followed by electroless nickel plating. Nickel microbumps also can be formed on the aluminum electrode without the displacement plating process. Activation of the aluminum surface is an indispensable process to initiate electroless nickel plating. Uniform bumps 20 μm wide and 15 μm high with good configuration were obtained by direct nickel plating after being activated with dimethyl amine borane.

Platinum modified aluminide diffusion coating and method

Abstract: A method of improving oxidation resistance of a platinum modified aluminide diffusion coating on a substrate involves electroplating the substrate with a platinum layer from an aqueous hydroxide based electroplating solution and aluminizing the substrate to grow the platinum modified aluminide diffusion coating on said layer. The electroplating solution preferably includes an alkali element and/or alkaline earth element that is incorporated in the platinum layer and in the aluminide diffusion coating formed thereon to significantly improve oxidation resistance of the coating.

New Methods of Electroless Plating and Direct Electroplating of Plastics

Abstract: SummaryA review of research work in two fields of metal deposition on dielectric surfaces is presented: (a) Electroless copper and silver deposition using unconventional reducing agents eg cobalt(II) complexes; a comparatively high plating rate is obtained, hydrogen is not evolved in the metal deposition process, and it is possible to regenerate the reducing agent in the plating solution.(b) The direct electroplating of plastics surfaces using a copper sulphide deposit as the conductive layer, which is formed by interaction of the plastics surface with solutions containing copper complexes and a source of sulphide ions. It is possible to electroplate with nickel or copper and obtain a high level of adhesion to the plastics surface.

Method of electroplating non-conductive plastic molded products

Abstract: A method of electroplating non-conductive plastic moldings, the method comprising the steps of: applying a catalyst useful for electroless plating to non-conductive plastic moldings using a colloidal solution containing a precious metal compound and a stannous compound; forming an electrically conductive coating on the surface of the moldings using an electroless copper plating solution containing a copper compound, a saccharide having a reducing property, a complexing agent and an alkali metal hydroxide; and electroplating the coated moldings. According to the method, an electroplated coating excellent in appearance and properties can be formed on non-conductive plastic moldings by a simple procedure.

Tin-silver alloy electroplating bath and tin-silver alloy electroplating process

Abstract: Disclosed is a tin-silver alloy electroplating bath containing: (A) stannous salt; (B) silver salt; (C) one kind or two or more kinds of acids selected from the group consisting of sulfuric acid, phosphoric acid, phosphonic acid, hydroxycarboxylic acid, alkanesulfonic acid, and alkanolsulfonic acid; (D) thiourea; (E) nonionic surface active agent; and (F) one kind or two or more kinds of additives selected from the group consisting of a mercapto group containing aromatic compound, dioxyaromatic compound, and unsaturated carboxylic acid. The electroplating using the above electroplating bath is allowed to form a homogeneous tin-silver alloy plated film having a good external appearance by eliminating preferential deposition of silver and substitutional deposition of silver on an anode and the plated film.

Metallization of Polymers Using Plasma‐Enhanced Chemical Vapor Deposited Titanium Nitride as Interlayer

Abstract: A low-temperature process for titanium nitride (TiN) deposition by means of an electron cyclotron resonance plasma chemical vapor deposition process was applied to poly(tetrafluoroethylene), polyimide, benzocyclobutene, and poly(butyleneterephthalate). The organometallic compounds tetrakis(dimethylamido)titanium or titanium(IV)isopropoxide introduced into the downstream region of a nitrogen electron cyclotron resonance plasma were used as precursors for TiN deposition at 100°C. The thin TiN film (thickness 15 to 30 nm) acts as a conductive interlayer for the electroplating process or as adhesion promoter for sputtered titanium films. Prior to the deposition of the interlayer, the samples were treated on a biased susceptor with argon ions to enhance the adhesion of the TiN interlayer. This metallization procedure avoids the use of toxic and pollutive etching agents for polymer activation as well as a electroless metal deposition. The maximum adhesion of the electroplated copper on poly(tetrafluoroethylene) and poly(butyleneterephthalate) was established to be 13 and 21 N mm -2 , respectively. For sputtered Ti films on polyimide and benzocyclobutene, maximum adhesion was 16 and 21 N mm -2 , respectively. As shown by atomic force microscopy, TiN grains were formed on the polymer surface. Film composition was investigated by secondary ion mass spectrometry.

Rough electrical contact surface

Abstract: A method for rendering a surface of a contact rough includes submerging the surface of the contact in an electroplating bath (18) having a dissolved metal salt, and pulsing an electric current through the contact and the bath (18) to form a rough metallic structure on the surface of the contact.

Method of electroplating non-conductive materials

Abstract: This invention provides a method of electroplating a non-conductive material, the method comprising the steps of bringing a non-conductive material into contact with an acidic hydrosol solution containing a palladium compound, a stannous compound and a copper compound, bringing the material into contact with an aqueous alkaline solution, and electroplating the material. According to the method of the invention, a desired coating having an excellent decorative appearance can be formed by electroplating without involving electroless plating on even a non-conductive material having a large area such as plastic molded components.

Adhesion of Copper Electroplated to Thin Film Tin Oxide for Electrodes in Flat Panel Displays

Abstract: The performance of large area and high resolution flat panel displays is contingent upon the conductivity of the transparent electrodes. Copper busbars plated to the sidewalls of the conventional SnO 2 electrode structure provide an order of magnitude enhancement in electrode conductivity while minimizing the loss in transmittivity to less than 3%. Essential to the above is sufficient adhesion between the copper and the SnO 2 . Previous work identified the need for an electrolytic reduction process, before copper plating, for adhesion to reach an acceptable strength, as observed by qualitative rubbing and peel tests. In this work, the electrochemical process conditions required for an adhesion strength of at least 100 kg/cm 2 are identified. Our results show that while both the current density and the electrical charge should be carefully chosen for optimum copper layer yroperties, the parametric selection can be made from a relative wide range of values. The suitable charge Q R , Q cu (C/cm ) and current densities J R , J CU (mA/cm 2 ) for the reduction and copper plating stages of the process are: 0.3 < Q R < 0.5, 0.3 < Q cu < 0.5, 31 < J R < 93, and 31 < J cu < 125. Under these conditions, the copper thickness is between 300 and 500 nm.

Localized electrochemical plating of interconnectors for microelectronics

Abstract: This work demonstrates the electrodeposition of micrometer scale copper structures including columns and interconnectors. Copper interconnectors of 25 /spl mu/m width were grown within an integrated circuit package using a simple instrument based on the scanning electrochemical microscope. In the present instrument electrodeposition is localized by applying a voltage between a closely spaced glass insulated Pt disk tip (diameter ca. 25 /spl mu/m) and a substrate, all immersed in a plating solution of acidified CuSO/sub 4/. The parameters that affect the deposition process are also addressed.

Electrochemical investigations of copper etching by Cu(NH3)4Cl2 in ammoniacal solutions

Abstract: Cyclic voltammetry has been employed to investigate the mechanism of copper etching in ammoniacal buffered solutions of cupric chloride Experiments involving an increase in the solution copper content (up to 05 m) and in the thickness of the copper electrode have been used to obtain a better understanding of the copper oxidation Whatever the Cu(ii) concentration, the reduction occurred in two one-electron stages leading successively to Cu(i) and Cu(0) The concentration of ammonia was an important parameter Increasing the ratio of Cu : NH3 favoured the formation of transient solid compounds The expected two-step oxidation of copper was observed only for thin layers of electroplated copper The determination of the corrosion current in etching solutions suggests that copper oxidation involves the formation of solid cuprous compounds

Electroplating additive for filling sub-micron features

Abstract: An electroplating system includes a standard electroplating apparatus using an acid copper bath with an additive for leveling The additive is chosen to have molecules of a size that is about the size of the features to be filled by the electroplating process The relatively large size of these additive molecules tends to hinder the mass transfer of the additive molecules into the features Consequently, the additive molecules are preferentially absorbed by the surface of the plating surface relative to the inner surfaces of the features Accordingly, the electroplating process tends to fill the features relatively quickly compared to the other parts of the target surface so that all of the surface area of the target is equivalent in height Because little or no additive molecules are within the features, the features tend to be filled without the voids often produced using conventional systems

In-situ cleaning processes for semiconductor electroplating electrodes

Abstract: Methods and apparatuses for in-situ cleaning of semiconductor electroplating electrodes to remove plating metal without requiring !the manual removal of the electrodes from the semiconductor plating equipment. The electrode is placed into the plating liquid and, an electrical current having reverse polarity is passed between the electrode and plating liquid. Plating deposits which have accumulated on the electrode are electrochemically dissolved and removed from the electrode.

Composition for electroplating palladium alloys and electroplating process using that composition

Abstract: An aqueous electroplating bath for the electrodeposition of palladium alloys in a mixed ligand system. A first ligand operates to form a complex of palladium and a second ligand functions to form a complex of another metal which brings the plating potentials of the two metals closer together. Palladium and the alloying metal thus exist as complexes with different structures.

Cyanide-free electroplating bath for deposition of gold and gold alloys

Abstract: Cyanide-free electroplating baths for deposition of gold and gold alloy coatings, using sulfurous gold complexes that are stable for a relatively long time, can be used with current densities over 1 A/dm2 and are practically odor-free, are obtained when the sulfurous compounds used are mercaptosulfonic acids, disulfide sulfonic acids or salts thereof.

Methods for plating semiconductor workpieces using a workpiece-engaging electrode assembly with sealing boot

Abstract: Methods used in semiconductor electroplating systems, such as for plating copper, onto a semiconductor wafer or other semiconductor workpiece. The methods apply to patterned metal layers plated onto a seed layer which is partially protected by an overlying photoresist or other coating. The methods employ an electrode assembly which has a boot which seals about a contact face of the electrode. The sealing is performed by engaging the seal against photoresist to prevent corrosion of the seal layer. The area enclosed by the sealing includes a via which is surrounded by the seal. The electrode contact extends through the via to provide electrical contact with the metallic seed layer. Plating of copper or other metal proceeds at exposed seed layer areas.

Acid tin-silver alloy electroplating bath and method for electroplating tin-silver alloy

Abstract: The invention relates to an acid tin-silver alloy plating bath which comprises tin ions, silver ions, one compound selected from the group consisting of aromatic thiol compounds and aromatic sulfide compounds, substantially non-cyanide and a balance of water, the pH of the bath being not higher than 2. According to this acid bath, tin and silver can be kept dissolved in the bath in a stable state for a long period of time even at a high temperature and a predetermined plating capacity is kept for a long period of time even though the bath is free from cyanide.

Method for electroplating of micron particulates with metal coatings

Abstract: A method of electroplating particulates in a metallic ion containing electrolyte within an electroplating device having an anode and cathode plate by repeating the steps of stirring the particulates, allowing sedimentation of the particulates to occur by gravity until a sedimentation layer of loosely contacted particles is formed on the cathode plate of a suitable thickness and applying an electromotive potential across said anode and cathode plate to create an electric current in said electrolyte for electroplating metallic ions on the surface of the particulates in said sedimentation layer wherein the steps of stirring, sedimentation and electroplating are performed in sequence over repeated cycles which are maintained essentially independent of one another with the step of electroplating being interrupted during the steps of stirring and sedimentation and with the step of stirring immediately following the step of electroplating.

Metallic porous body for secondary battery and its manufacture

Abstract: PROBLEM TO BE SOLVED: To provide a metallic porous body for a secondary battery having sufficient strength and high porosity, and its manufacturing method. SOLUTION: A sheet having a thickness of 0.6-4.0 mm is sliced off a soft slab foam that is produced by means of a normal method and has cells to the number of 30-150 per 25 mm, and this sheet is heated and pressurized for 3-180 sec at a temperature in the range of 180-220°C so as to form it into a compressed sheet having a thickness in the range of 0.1-2.0 mm. This compressed sheet is plated with metal plating such as nickel plating or the like by means of electroless plating, electroplating or the like. Thereafter, the foams are eliminated by means of reducing roasting or the like and thereby, a metallic porous body, having a porosity in the range of 80-98%, for a secondary battery is obtained. COPYRIGHT: (C)1999,JPO