At&t Bell Laboratories

At+t Corp.

Joseph J Maisano, Jr

Joseph Anthony Abys

Igor V Kadija

Heinrich K Straschil

Edward J Kudrak, Jr

Shohei Nakahara

Virginia T Eckert

Vijay Chinchankar

A cyanide based aqueous solution for stripping palladium from copper-containing substrate. The solution includes a cyanide radical source compound, Na.sub.2 CO.sub.3, a nitrobenzoic acid, NaOH, thallium compound, an organo mercapto compound, and water. The presence of the organo mercapto compound in thallium containing cyanide bath permits efficient stripping of palladium from copper containing substrates with minimum corrosion damage to the substrate.

Chemical etchant for palladium

A packaged device with a lead frame, a lead frame and an article of manufacture comprising a base metal, a layer of nickel on the base metal, and a protective composite of metal layers on the nickel. The composite includes, in succession from the nickel layer, a layer of palladium or soft gold strike, a layer of palladium-nickel alloy, a layer of palladium and a layer of gold. The palladium or soft gold strike layer acts primarily as a bonding (an adhesive) layer between the Ni and Pd-Ni alloy layers and as a layer that enhances reduction in porosity of subsequent layers, Pd-Ni alloy layer acts as a trap for base metal ions, Pd layer acts as a trap for Ni ions from the Pd-Ni alloy layer, and the outer gold layer synergistically enhances the quality to the Pd layer. The various layers are in thickness sufficient to effectively accomplish each of their designated roles, depending on the processing and use conditions. Pd on soft Au strike layer may be 1-5 microinches thick, Pd-Ni alloy layer from 4 to 100 microinches, Pd layer from 1 to 100 microinches and the outer gold layer from 1 to 100 microinches in thickness.

Integrated circuit devices with solderable lead frame

This invention pertains to an apparatus and method for measuring throwing power of electroplating solutions. The apparatus is easy to use and gives reproducible measurements. The apparatus emulates the performance of a conventional Haring Blum cell. The major disadvantage of the standard Haring Blum cell is its limited aility to vary the solution mass transport, thus limiting its applicability to very low current density applications. Furthermore, even under low-mass transport conditions, non-uniform solution distribution is experienced leading to erroneous interpretation. This invention permits the study of throwing power of electroplating solutions under a whole variety of solution agitation. The invention embodies an instrument for and a method of measuring the throwing power of electrolytes. The instrument is in a form of an elongated cylindrical body adapted for rotation about its longitudinal axis and includes a fixed conductive anode element and at least two cathode elements, at least one of which is variably spaced from the anode element. Preferably, one cathode element is fixed relative to the anode element a first predetermined distance and another cathode element is spaced from the anode element a second variable distance which is a multiple of the first distance. The instrument also includes means for providing current to the anode element and equi-potentially to each of the cathode elements. The measuring includes providing each of the cathode elements with a pre-weighed removable metal foil, rotating the instrument which the anode and cathode elements are completely submerged in an electrolyte, applying current to the anode and the cathode elements, removing the metal foils from the cathode elements and weighing the metal foils with the deposit thereon to compare the weight of deposited metal at different cathode element positions.

Rotating cylinder-throwing power electrode

This invention is concerned with production of electrical devices comprising an electrodeposited conductive region free from cracking defects. In the production of a contact portion of the device from a metal strip electroplated with a conductive stripe of an alloy, the stripe exhibited, upon stamping and forming operation, cracked areas. Typically, the stripe coating on the metal strip, such as a copper bronze material, includes a layer of nickel, a layer of palladium alloyed with nickel, cobalt, arsenic or silver, and a flash coating of hard gold. The cracking defects were eliminated by subjecting the plated strip to an annealing treatment prior to the stamping and forming operation. After the heat-treatment, the stripe was free from cracks and separations between the successive layers.

Thermal annealing of palladium alloys

This invention embodies a process for synthesizing electrodialythically palladium ammine hydroxide for use in palladium plating baths. The electrodialysis takes place in a cell with a catholyte, a product and an anolyte compartments which are divided by a fluorinated anion permselective membranes. Catholyte solution readily supplies OH ions, raw starting solution contains palladium ammine ions and anions capable of migrating into the anolyte compartment, and anolyte solution readily absorbs the anions from the raw solution. Electrodes, placed in the outer compartments, are placed no more than 5 cm apart. The process is conducted with current densities of 500 ASF or less, with 200 ASF being preferable, with current efficiencies of 50 to 90 percent, with 60-80 percent being preferable, and at bath temperatures of from above freezing to 40.degree. C., with 25.degree.-40.degree. C. being preferable. The electrodialysis results in a stable palladium diammine hydroxide solution containing a small fraction of starting palladium diammine compound, such as palladium diammine chloride, making the final solution readily useable either as a replenishing or a plating solution.

Electrochemical synthesis of palladium hydroxide compounds

A process for electroplating palladium containing deposits from baths comprising a combination of a surfactant and a brightener combination. The surfactant is an alkyl, ammonium-type salt containing 4 to 35 carbon atoms. The brightener is 0-benzaldehydesulfonic acid, 1-naphthalene sulfonic acid, 2-naphthalenesulfonic acid, benzenesulfinic acid, oxy-4,4-bis (benzene) sulfinic acid, p-toluene sulfinic acid, 3-trifluoromethyl benzene sulfinic acid, allyl phenyl sulfone, 0-benzoic sulfamide, benzylsulfonyl propionamide, phenylsulfonyl acetamide, 3-(phenylsulfonyl) propionamide, benzene sulfonamide, bis (phenylsulfonyl) methane, guanidine carbonate, sulfaguanidine or nicotinic acid. This combination provides deposits having superior adhesion and ductility.

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Denville, NJ, United States of America

Joseph J Maisano, Jr