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Showing papers on "Electroplating published in 1988"


Journal ArticleDOI
TL;DR: In this paper, a mathematical model is developed to simulate the electrodeposition of Cu-Ni alloy from citrate solutions onto a rotating disk electrode under potentiostatic control, including the influence of diffusion, ionic migration, forced convection, and homogeneous equilibria.
Abstract: A mathematical model is developed to simulate the electrodeposition of Cu-Ni alloy from citrate solutions onto a rotating disk electrode under potentiostatic control. The model includes the influence of diffusion, ionic migration, forced convection, and homogeneous equilibria. The three major electrochemical reactions treated in the model are copper deposition, nickel deposition, and hydrogen evolution. Using experimental parameters when available, the model was fitted and tested against experimentally-obtained results for different bath compositions and operating conditions. The model agreed reasonably well with the experimental results particularly in the codeposition region, 1.0 to 1.2V vs. SCE, where hydrogen evolution is not the major reaction. Also, the model 's predictive capabilities are evaluated. Electrodeposition of copper-nickel alloys has potential industrial applications due to the alloy's resemblance to Monel alloy, which is widely used in marine installation. For instance, the corrosion current densities of a 20-30% * Electrochemical Society Active Member. 1Present address: Digital Equipment Corporation, Colorado Springs, Colorado 80907. copper alloy coating in a 3% NaC1 solution have been measured to be between 0.3 and 0.6 ~A/cm 2, which are similar to the corrosion rate of Mone1400 (1). Thus, a sound, coherent Cu-Ni alloy deposit can be used as a protective coating against such salt environment. Other attractive features, besides corrosion resistance, include malleability, ductility, and solderability. Downloaded 13 Jun 2011 to 129.252.106.20. Redistribution subject to ECS license or copyright; see http://www.ecsdl.org/terms_use.jsp Vol. 135, No. 12 COPPER-NICKEL ALLOYS 2965 The Cu-Ni alloy p la t ing p rocess is classified as a normal alloy depos i t i on type s ince the m o r e nob le metal , cop p e r in th is case, depos i t s p re fe ren t ia l ly (2). Very of ten a comp l ex ing agent is n e e d e d to codepos i t the metals . Over the years, m a n y c o m p l e x agents have b e e n tried; the consensus is tha t c i t rate and p y r o p h o s p h a t e are the m o s t promising ones (1-5). As wi th m o s t no rma l type of alloy deposi t ion, t he cond i t ions n e e d e d to pla te a h igh-n icke l alloy depos i t are a m u c h h ighe r ratio of n icke l to -copper in solut ion as well as a large appl ied cu r r en t densi ty . Other impo r t an t p a r a m e t e r s inc lude the pH, agitation, and tempera ture . P r i sco t t (3) found tha t the ca thode cur ren t eff ic iency d r o p p e d as the pH was lowered. Also, he s h o w e d tha t the coppe r con t en t in the alloy depos i t inc reased sl ight ly wi th agitation. These pa ramete r s , namely , so lu t ion compos i t ion , depos i t ion potent ia l (or current) , pH, and agitat ion, will be e x a m i n e d fu r ther in our report . However , t he effect o f t e m p e r a t u r e was negl ig ib le (3) and was no t s tudied. Commerc ia l ly usefu l alloys in t e r m s of depos i t compos i t ion, morpho logy , and adhes ion are difficult to obtain. There appear s to be a na r row range of sui table opera t ing cond i t i ons for a sound , cohe ren t deposi t . O the rwise t he depos i t can be dark, \"burn t , \" and powdery . Mos t s tud ies (1-5) re la ted the depos i t compos i t i on as a func t ion of t he app l i ed cu r ren t densi ty , w h i c h is s t rongly d e p e n d e n t on the so lu t ion compos i t ion . Unfor tuna te ly , t he so lu t ion c o m p o s i t i o n s var ied so wide ly tha t it is difficult to d raw usefu l i n fo rma t ion f rom such studies . We f o u n d the n e e d to u n d e r s t a n d the f u n d a m e n t a l a spec t s invo lved in the Cu-Ni alloy p la t ing p rocess as well as to m o d e l the s y s t e m for genera l appl icat ion. The previous r epo r t (6) deal t w i th t h e fo rmer topic. In tha t p a p e r (6), five e l ec t rochemica l reac t ions were ident i f ied to occur during Cu-Ni alloy e lec t rodepos i t ion . Coppe r and n ickel codepos i t in a na r row potent ia l region, -1 .0 to -1 .2V vs. SCE, w h e r e the effects of the o ther th ree e lec t rode reac t ions are small. S o m e of the mass t r anspor t and kinet ic pa r ame te r s for t he codepos i t i on p rocess were de t e rmined . Also, the alloy depos i t s were p la ted at cons t an t po ten t ia l s and characterized. The e lec t rode po ten t ia l in s t ead of t he cu r r en t dens i ty was c h o s e n as the opera t ing var iable for convenience. In t he p r e sen t repor t , a ma thema t i ca l m o d e l is dev e l o p e d to desc r ibe the codepos i t i on of c o p p e r and nickel in a ci t rate solution. The m o d e l t akes into accoun t factors affecting the transport of species in solution such as diffusion, migration, and forced convection. In addition, the homogeneous chemical equilibria among the species in the plating solution are also considered. The model was tested against the experimental results from our previous work (6) and was also used for predicting the optimum plating conditions. Recently, Mathias and Chapman (7) applied a similar model to the Zn-Ni alloy system. They were able to predict the alloy composition fairly well; however, the disagreement between the model prediction and the polarization data demonstrated that their kinetic model was inappropriate in describing the anomalous behavior of Zn-Ni alloy plating. However, the Cu-Ni system behaves more ideally such that its codeposition is classified as normal and that it exhibits a continuous series of homogeneous solid solutions. Equil ibrium Bulk Condit ions In m o d e l i n g the alloy depos i t ion process , it is essent ia l to k n o w the bu lk and surface concen t r a t ions of t he react an t s in order to assess the m a g n i t u d e of the mass t r ans fe r ef fec ts and reac t ion rates. As m e n t i o n e d earlier, t he copper -n icke l alloy pla t ing ba th typical ly requ i res a complex ing agen t to codepos i t the metals . Citrate, one of t he m o s t p r o m i s i n g l igands for t he Cu-Ni alloy sys tem, is u s e d in the p r e s e n t s tudy. The bu lk concen t r a t ions are ca lcula ted by us ing the equ i l ib r ium cons tan ts , mater ia l conse rva t ion equa t ions , and the e lec t roneut ra l i ty condi t ion . Acco rd ing to the l i te ra ture (8-10) in a ba th con ta in ing coppe r sulfate (CuSO4 5H20), n icke l sulfa te (NiSO4 9 6H20), and s o d i u m ci t rate (Na3C6H~O7 2H20), t he fol lowing equi l ibr ia are poss ible Cu 2+ + Cit 3~CuCit [1] Cu ~+ + HCit 2~CuHCit [2] HCit 2 ~ H + + Cit 3 [3] H2Cit ~ H § + HCit 2 [4] H3Cit ~ H + + H2Cit[5] Ni 2+ + Cit 3~NiCit[6] Ni 2+ + HCit 2~ NiHCit [7] SO42+ H + ~ H S O ( [8] H 2 0 ~ O H + H + [9] w h e r e Cit ~ is C6H~O73 . The mater ia l ba lances for the species in Eq. [1]-[9] are [Cu2+]tot,~ = [Cu 2+] + [CuCit ] + [CuHCit] [10] [Ni2+]tot,~ = [Ni 2+] + [NiCit-] + [NiHCit] [11] [Cit3-]tot~l = [Cit 3-] § [CuCit-] + [CuHCit] + [NiCit-] + [NiHCit] + [HCit 2-] + [H2Cit-] + [H3Cit] [12] [SO42-]to~1 = [SO42-] + [HSO4 ] [13] w h e r e [i]tot~ is the concen t ra t ion of spec ies i a d d e d to t he bu lk solution. The e lec t roneut ra l i ty cond i t ion is ZiC i : 0 [14] i The equ i l ib r ium cons tan t s for Eq. [1]-[9] are l i s ted in Table I. The a lgor i thm for the equ i l ib r ium calcula t ion is ou t l ined in the Append ix . Basically, the p ro g ram uses t he exper i men ta l ly m e a s u r e d pH and the initial spec ies concent ra t ions, [/]total, to calculate the equ i l ib r ium concen t r a t i ons of all species . The c o m p u t e d resul ts are g iven in Table II for the th ree pla t ing solut ions: Cu-5, Cu-10, and Cu-20 baths , w h i c h are labeled accord ing to the pe rcen tage of cupr ic ion in the solu t ions conta in ing 0.19M total meta l ion concent ra t ion . The m e a s u r e d pH values for t hese ba ths are 5.37, 5.06, and 4.76, respect ively . In order to sat isfy e lec t roneutra l i ty , a p s e u d o spec ies was conce ived to allow for any u n k n o w n spec ies in the soTable I. Equilibrium constants Reaction j Constant Reference 1 1.58 • 10 TM liter/mol Lange (8) 2 2.22 • 104 liter/mol Lange (8) 3 4.02 x 10 -7 mol/liter CRC (9) 4 1.75 • 10 _5 mol/liter CRC (9) 5 7.43 x 10 -4 mol/liter CRC (9) 6 1.99 x 1014 liter/mol Lange (8) 7 1.29 x 102 liter/mol Lange (8) 8 8.33 x 101 liter/mol CRC (9) 9 1.OO x 10 -14 (mol/liter) 8 CRC (9) Table II. Concentrations for the three plating baths Bath Cu-5 a Cu-10 b Cu-20 ~ Species i c~ | c~ ~(mol/liter) ci.| CuCit 0.9500 X 10 -2 0.1900 X 10 -1 0.3800 x 10 1 CuHCit 0.1416 x 10 -1~ 0.5781 • 10 -1~ 0.2307 x 10 -9 Cu 2+ 0.1312 • 10 -13 0.6200 x 10 -18 0.3256 x 10 -12 Cit 80.4573 x 10 -2 0.1936 x 10 -8 0.7373 x 10 3 HCit 20.4853 • 10 1 0.4194 • 10 1 0.3187 x 10 -1 H2Cit0.1183 • 10 -1 0.2088 • 10 -1 0.3165 x 10 1 H3Cit 0.6792 x 10 -4 0.2447 x 10 8 0.7402 • 10 -8 NiCit0.1805 x 10 ~ 0.1710 • 10 ~ 0.1520 • 10 ~ NiHCit 0.1242 x 10 -8 0.2402 x 10 -8 0.4259 x 10 -8 Ni 2+ 0.1983 • 10 -12 0.4439 X 10 -12 0.i036 • 10 -11 SO42 0.1899 • 10 o 0.1899 • I0 ~ 0.1897 • i0 ~ H S O ( 0.6749 • 10 -4 0.1377 x 10 3 0.2746 x 10 -8 H + 0.4266 • 10 -5 0.8710 • 10 5 0.1738 x 10 -4 OH0.2344 • 10 -8 0.1148 • 10 -8 0.5754 • 10 -9 Na + 0.7650 x I0 ~ 0.7650 • 10 o 0.7650 • i0 ~ Pseudo0.7246 • I0 -I 0.8458 • 10 -~ 0.9769 • 10 -1 a Cu-5: [CuSO4] = 0.0095M, [NiSO4] = 0.1805M, [Na3Cit] = 0.255M b Cu-10: [CuSO4] = 0.019M, [NiSO4] = 0.171M, [Na3Cit] = 0.255M c Cu-20: [CuSO4] = 0.038M, [NiSO4] = 0.152M, [NasCit] = 0.255M Downloaded 13 Jun 2011 to 129.252.106.20. Redistribution subject to ECS license or copyright; see http://www.ecsdl.org/terms_use.jsp 2966 J. Electrochem. Soc.: E L E C T R O C H E M I C A L S C I E N C E A N D T E C H N O L O G Y December 1988 lu t ions . Usual ly , t he pH of t h e de ion ized w a t e r was f o u n d to b e less t h a n 7, s u g g e s t i n g t h a t some u n k n o w n a n i o n s were o m i t t

99 citations


Patent
23 Mar 1988
TL;DR: In this paper, an anode used in electroplating is formed by a plurality of individual anode segments arranged in predetermined patterns, and the segments of certain patterns are selectively energized to establish an effective anode size that relates to the size of the article to be electroplated, thereby establishing an electrical field of uniform characteristics to transfer ions from the anode to the article at a uniform deposition rate over the whole surface of an article.
Abstract: An anode used in electroplating is formed by a plurality of individual anode segments. The anode segments are arranged in predetermined patterns. The segments of certain patterns are selectively energized to establish an effective anode size that relates to the size of the article to be electroplated, thereby establishing an electrical field of uniform characteristics to transfer ions from the anode to the article at a uniform deposition rate over the whole surface of the article. By adjusting the effective size of the anode to correspond or relate to the size of the article, the non-uniform deposition rates associated with concentrated localized field are avoided, and the physical size of the electroplating apparatus can be reduced. An electrophoretic ion filter is also placed between the cathode and the article. This ion filter is preferably formed of a plastic porex material, such as porous polypropylene or polyethylene.

81 citations


Patent
10 May 1988
TL;DR: In this paper, a method for simultaneous selective plating of viaholes and heat sinks associated with a semiconductor wafer using a metal mask was proposed, which consists of coating a first side of the wafer with an insulating layer to prevent electroplating on this first side; patterning on a second side of wafer opposite to the first side, and depositing a thin conductive film to coat the bottom and walls of the via-holes as well as areas of the second side not covered by the metal mask.
Abstract: A method for simultaneous selective plating of viaholes and heat sinks associated with a semiconductor wafer using a metal mask and comprising the steps of: (a) coating a first side of the wafer with an insulating layer to prevent electroplating on this first side; (b) patterning on a second side of the wafer, opposite to the first side, a metal mask for defining the areas where plating should not occur; (c) forming via-holes through said wafer; (d) depositing a thin conductive film to coat the bottom and walls of the via-holes as well as areas of the second side of the wafer not covered by the metal mask; and (e) electrolytically plating the resulting wafer while ultrasonically agitating the electrolyte if necessary to ensure sufficient electrolyte transport into the via-holes for uniform plating

77 citations


Journal ArticleDOI
TL;DR: In this article, the authors used cyclic voltammetry to show a reduction peak followed by passivation for halogenosilanes and showed that C (∼8), O(∼ 8), and Cl ( ∼ 1.5) are impurities (atomic percent).
Abstract: Electroplating of silicon from solutions of , , , , , , and in tetrahydrofuran, using , TBAP, or TBAB as supporting electrolyte has been studied Si‒C, Si‒O, and Si‒N bonds are not reduced. Cyclic voltammetry shows a reduction peak, followed by passivation, for the halogenosilanes. Potentiostatic and galvanostatic deposition on Pt, Au, Ni, Cu glassy carbon, or ITO glass yields smooth layers up to 0.25 μm. Thicker layers have cracks. Auger spectroscopy shows C (∼8), O (∼8), and Cl (∼1.5) as impurities (atomic percent).

75 citations





Patent
21 Jul 1988
TL;DR: In this paper, a method of making an electrical multilayer copper interconnect in which the electrical lines are protected by an electroplated overcoat is described. But this method is not suitable for the case of single-layer interconnects.
Abstract: A method of making an electrical multilayer copper interconnect in which the electrical lines are protected by an electroplated overcoat. A plating interconnect is deposited on a substrate, a sacrificial layer of dielectric material is deposited on the plating interconnect. Thereafter a plating mask is formed on the dielectric material. Two self-aligned plating masks are patterned in one step, one of which is a plating mask for copper plating and the other is a plating mask for the overcoat. Preferably, before electroplating the overcoat, the copper is etched for exposing the sides adjacent the dielectric layer for allowing overcoating all of the copper.

52 citations


Patent
06 Sep 1988
TL;DR: In this article, a process for electroplating metals in an anode and a cathode has been described, where the cathode is formed by a workpiece to be plated and the anode includes soluble material in the form of the metal to be removed and insoluble material in a proportion selected so that the anodes efficiency equals the cathodes efficiency.
Abstract: A process for electroplating metals in an electroplating bath having an anode and a cathode. The cathode is formed by a workpiece to be plated and the anode includes soluble material in the form of the metal to be plated and insoluble material in a proportion selected so that the anode efficiency equals the cathode efficiency. This avoids metal salt build-up in the bath. Metal salt solution carried out of the bath with the workpiece is recovered and recycled to the bath, avoiding loss of metal to the system and waste disposal problems.

51 citations


Patent
08 Feb 1988
TL;DR: In this paper, an improved electroplating apparatus with an anode, cathode and diaphragm ring was presented, which is composed of a plastic tube whose lower opening is covered by a wafer holder for holding the semiconductor wafer.
Abstract: The present invention provides an improved electroplating apparatus having an electroplating cell equipped with an anode, cathode and diaphragm ring. The electroplating cell is suspended in an electrolytic bath. The cell is composed of a plastic tube whose lower opening is covered by an anode surface and whose upper opening is covered by a wafer holder for holding the semiconductor wafer. The electroplating apparatus further includes an activated carbon filtering aimed at the levelling effect.

46 citations


Patent
15 Sep 1988
TL;DR: In this paper, a method for metal plating the surface of an article formed from an organic plastic is described. But the method is not suitable for the formation of printed circuit boards and is not sufficiently versatile to permit formation of a printed circuit board by a process that involves pattern plating.
Abstract: A method for metal plating the surface of an article formed from an organic plastic. The method includes a step of passing a current between two electrodes immersed in an electrolyte containing dissolved plating metal. One of the electrodes is the article to be plated and is provided with a surface having areas of a catalytic metal chalcogenide conversion coating adjacent to and in contact with conductive areas. In a preferred embodiment, the catalytic metal chalcogenide conversion coating is formed by treating the article with an acid colloidal solution of a tin-noble metal electroless metal plating catalyst and, subsequently, treating with a solution containing a dissolved sulfide to form a sulfide of the noble metal. The conversion coating allows the article to be directly electroplated. The method is especially useful for the formation of printed circuit boards and is sufficiently versatile to permit formation of a printed circuit board by a process that involves pattern plating.

Journal ArticleDOI
TL;DR: In this paper, the potentiostatic electrodeposition of Cu 2 O onto stainless steel at 60°C is discussed and it is demonstrated that monitoring the deposition parameters during the growth of films can be useful in extracting further knowledge about the type of deposition process and the electrolyte.

Journal ArticleDOI
TL;DR: In this paper, thin film nickel-phosphorus alloys are electrodeposited at a high rate using a specialized rapid electrolyte flow system, where current densities up to 2.33 A/cm2, which are difficult to maintain in conventional plating processes, can be used to produce satisfactory films.
Abstract: Thin film nickel‐phosphorus alloys are electrodeposited at a high rate using a specialized rapid electrolyte flow system. Current densities up to 2.33 A/cm2, which are difficult to maintain in conventional plating processes, can be used to produce satisfactory films. The deposits are characterized by x‐ray diffraction and differential scanning calorimetry. Phosphorus content decreases with increasing current density and is virtually independent of the electrolyte flow rate above 5.7 m/s, where the system is operating in the turbulent regime. Deposit structure depends strongly on the phosphorus content; it is amorphous or highly microcrystalline at >14 atom percent (a/o) and crystalline at <14 a/o. The low phosphorus deposits decompose directly from a solid solution of nickel and phosphorus to a mixture of nickel and nickel phosphide at a temperature in the range of 380°–420°C. The high phosphorus deposits transform first to a metastable intermediate which subsequently transforms to nickel and nickel phosphide at higher temperatures.

Patent
29 Apr 1988
TL;DR: A plating bath and process for electroplating coatings of palladium nickel alloys on a conductive substrate at current densities in the range of 10 amps/sq. ft. to 150 amps/square ft. was described in this paper, wherein the palladium content of the alloy remains substantially constant despite current density variations during plating.
Abstract: A plating bath and process for electroplating coatings of palladium nickel alloys on a conductive substrate at current densities in the range of 10 amps/sq. ft. to 150 amps/sq. ft. wherein the palladium content of the alloy remains substantially constant despite current density variations during plating. The alloy composition stability is achieved by adding at least about 15 parts per million of iodide and/or iodate ions to the plating bath. The as-plated alloy has a thin surface layer which contains iodide at or near the surface.

Patent
25 Apr 1988
TL;DR: In this article, an electroplating bath for forming a zinc-nickel alloy coating consisting essentially of water, about 1 to 70 grams/liter of zinc, about 0.6 to 118 grams per liter of nickel, at least one compound from the group consisting of (i) aliphatic amines in an amount not more than 16 grams /liter, (ii) polymers of aliphastic amines, in an amounts not more about 20 grams perliter and (iii) a compound selected from the groups consisting of hydroxyaliphatic carboxylic acids
Abstract: The invention provides an electroplating bath for forming a zinc-nickel alloy coating consisting essentially of water, about 1 to 70 grams/liter of zinc, about 0.6 to 118 grams per liter of nickel, at least one compound from the group consisting of (i) aliphatic amines in an amount not more than 16 grams/liter, (ii) polymers of aliphatic amines in an amount not more than about 20 grams per liter and (iii) a compound selected from the group consisting of hydroxyaliphatic carboxylic acids and salts thereof in an amount from 0 to 2 mols/liter, said bath having a pH of more than 11. The invention also provides an electroplating method for forming a chromate coating on a zinc-nickel alloy coating electrolytically deposited from the electroplating bath defined in the preceding sentence on electrically conductive metalics matrix material, and forming a chromate coating on the zinc-nickel alloy coating by means of a chromate treatment.

Patent
03 May 1988
TL;DR: In this article, an exterior stainless steel sheet is provided comprising a stainless steel substrate and a coating layer formed on one surface of the steel substrate from Al, Al alloy, Zn or Zn alloy to a thickness of 0.1 to 70 μm.
Abstract: An exterior stainless steel sheet is provided comprising a stainless steel substrate and a coating layer formed on one surface of the steel substrate from Al, Al alloy, Zn or Zn alloy to a thickness of 0.1 to 70 μm, preferably 1 to 70 μm. A Zn or Zn-Ni alloy plated stainless steel strip is prepared by degreasing a stainless steel strip, substantially activating the surface of the strip, and electroplating the strip by immersing the strip in a hydrochloric acid solution having a concentration of 0.5 to 40 wt % in a zinc or zinc-nickel alloy plating bath at pH 3.5 or lower. Alternatively, activation may be carried out by cathodic electrolytic treatment in a hydrochloric acid solution having a concentration of 0.5 to 40 wt % at a current density of 0.1 to 100 A/dm. During electroplating of one side, the other side of the strip not to be plated is covered with a protective film. A stainless steel sheet comprising a stainless steel substrate and a coating layer formed on one surface of the steel substrate from Zn or Zn alloy to a thickness of 0.1 to 50 μm, preferably 1 to 50 μm is useful in preparing welded pipes.


Patent
11 Jul 1988
TL;DR: In this paper, an adherent metal undercoating is applied to the surface of the metal substrate which weakly or not at all chemisorbs carbon monoxide, then applying the desired outercoat metal to the undercoat substrate by chemical vapor deposition, using a heat decomposable metal carbonyl as the source of the desired inner coating metal.
Abstract: Adherent metal coatings of metals that cannot be adherently applied directly onto a desired substrate metal by chemical vapor deposition at a temperature below about 300° C. are obtained by applying an adherent metal undercoating to the surface of the metal substrate which weakly or not at all chemisorbs carbon monoxide, then applying the desired outercoat metal to the undercoat substrate by chemical vapor deposition, using a heat decomposable metal carbonyl as the source of the desired outer coating metal. The undercoating metal may be applied by conventional plating processes such as electroplating or electroless plating. In preferred embodiments, the substrate is iron or steel or their alloys, the undercoating metal is copper, and the outer coating metal is a ferrous metal, i.e., nickel, iron, or cobalt.

Journal ArticleDOI
TL;DR: In this paper, a new technique based on an optical fiber interferometer is described for in situ measurement of electrode strain during electrode reactions, which relates changes in optical path length of the fibers in the various strain components in the electrode.
Abstract: A new technique, based on an optical fiber interferometer, is described for in situ measurement of electrode strain during electrode reactions. A model is presented which relates changes in optical path length of the fibers in the various strain components in the electrode. Measurements of strain associated with electrodeposition of nickel as a function of the thickness of the nickel layer are reported and compared to a simple model. Measurements of strain associated with the anodic oxidation of titanium are also reported. The strain generated in the titanium has a component which is independent of applied potential after oxide growth is complete and a component which is dependent on the applied potential. The potential dependent term is identified as an electrostriction effect in the anodic oxide enhanced by the porous nature of the electrode. The potential independent term comes from compressive stress in the anodic oxide induced by the growth process.

Patent
27 Dec 1988
TL;DR: Selective electrolytic deposition is provided on a body having a conductive surface comprised of two different conductive materials in which one of the materials forms a surface layer upon exposure to a particular ambient environment as discussed by the authors.
Abstract: Selective electrolytic deposition is provided on a body having a conductive surface comprised of two different conductive materials in which one of the conductive materials forms a surface layer upon exposure to a particular ambient environment and wherein that surface layer prevents electroplating on that material in the particular electroplating environment utilized for the electroplating of the desired pattern on the other conductive material.

Patent
14 Jul 1988
TL;DR: In this paper, a lead frame for a semiconductor device includes a metal strip made of copper or copper alloy having a plurality of wire bonding areas to which metal wires are directly connected by direct bonding method.
Abstract: A lead frame for a semiconductor device includes a metal strip made of copper or copper alloy having a plurality of wire bonding areas to which metal wires are directly connected by a direct bonding method. The wire bonding areas are electroplated with a thin silver film or a palladium film, so that formation of a copper oxidized film on the wire bonding area is substantially prevented.


Journal ArticleDOI
TL;DR: In this paper, a new pre-treatment sequence was designed to improve the coverage rate of zinc alloy films, chemically deposited prior to nickel electroplating, which consists of a double-step nitric + hydrofluoric acid solution immersion, with NaOH immersion treatment between the two acid immersion steps.
Abstract: The effects of concentration and temperature of sodium hydroxide and nitric acid + hydrofluoric acid pretreatment solutions on the morphology of aluminium surfaces have been studied SEM/EDS observations indicated that NaOH solutions produced etch concavities on the surface, but failed to etch second-phase particles, namely FeAl3 The acid solutions, however, succeeded in preferentially removing these particles, while they did not change the surface roughness of the aluminium In an attempt to improve the coverage rate of zinc alloy films, chemically deposited prior to nickel electroplating, a new pretreatment sequence has been designed It consists of a double-step nitric + hydrofluoric acid solution immersion, with NaOH immersion treatment between the two acid immersion steps The results obtained with this new sequence indicate that the first acid step removes most of the biggest FeAl3 particles, as well as the previous oxide layer, while the alkaline step generates a micro-roughness on the surface whereby a net of shallow cellular cavities, as in a honeycomb structure, forms The last acid treatment preferentially etches the small FeAl3 particles and the most protuberant inhomogeneities of the surface This new pretreatment sequence proved to be more effective than those previously reported in the literature, in terms of producing a good surface on which zinc alloy films could develop The adhesion of nickel electrodeposits to such a surface reached values one order of magnitude higher than those for conventional two-step sequences Interpretation of these results is based on the improved chemical homogeneity of the surface resulting from the removal of second-phase particles and on the small (ca 1 μm in diameter) and uniform dimensions of the cells produced by the etch treatment This effectively leads to a good surface coverage during the zincate treatment, as intially intended

Journal ArticleDOI
TL;DR: In this article, the electrodeposition of copper and silver on polycrystalline ruthenium was studied by the potentiodynamic method, in aqueous and aprotic media (propylene carbonate).

Patent
12 Dec 1988
TL;DR: In this paper, a printed circuit board manufacturing process is disclosed which provides good solderability, a non-reflowable coating under the solder mask, and provides a completely uniform flat surface for surface mount components.
Abstract: A printed circuit board manufacturing process is disclosed which provides good solderability, a non-reflowable coating under the solder mask, and provides a completely uniform flat surface for surface mount components. An electroplated tin/nickel surface is disposed on a copper coated circuit board. Rather than maintaining the solderability of the tin/nickel by immediately coating the surface with gold, a solder mask first is disposed on the electroplated nickel. The solder mask serves the dual role of identifying the conductivity and soldering points and also identifying those selected areas for coating with gold. Thereafter, a very thin and closely controlled layer of gold is disposed on the activated tin/nickel using a non-autocatalytic immersion process to selectively apply gold only to areas open for conductivity or solderability.


Patent
14 Dec 1988
TL;DR: In this paper, a metal thin film is formed on the surface of a plate-like conductive base, which is subjected to an electrolytic bath using a resist mask to leave only a conductor circuit layer 14 unremoved on the thin film.
Abstract: PURPOSE:To eliminate troubles caused by the dispersion of solder in thickness by a method wherein a metal thin film is formed in a common state on the surface where a solder connecting section is formed CONSTITUTION:A metal thin film 12 is formed on the surface of a platelike conductive base 11, which is subjected to an electrolytic bath using a resist mask 13 to leave only a conductor circuit layer 14 unremoved on the metal thin film 12 Next, the conductor circuit layer 14 is laminated on an insulating base 15 with the thick conductive base 11 into an integral piece, which is pressure-bonded or hot pressure-bonded to transfer the conductor circuit layer 14 to the insulating base 15 side As the metal thin film 12 and the conductor circuit layer 14 are combined together with high adhesive power, so that the conductor circuit layer 14 is prevented from moving to deviate at a transferring process And, the surface of a solder layer 13 formed on a metal plating layer 13 through an electroplating method is smooth and the layer 13 is all uniform in thickness By this setup, problems such as a Manhattan phenomenon and the like caused by the dispersion of a solder layer in thickness can be prevented

Journal ArticleDOI
TL;DR: In this article, the authors introduced the concept and practice of the deposition of metal on vesicles by using electroless plating techniques, and showed that colloids were formed that were stable in water for much longer periods than the control metal particles formed in water alone.
Abstract: The encapsulation of metallic particles and metallic oxides within lipid vesicles has recently been of interest for applications such as catalysis, water splitting, and magnetic control of spin coupling. In this communication the authors introduce the concept and practice of the deposition of metal on vesicles by using electroless plating techniques. Coordination of low valent transition metals to organic functional groups on the surface of the bilayer membrane provides a means of binding metal atoms to vesicles. Chemical reduction produced zero valent atoms which serve as sites for further metal deposition by the chemical reduction techniques of electroless plating. Specifically, this procedure involved the binding of a small amount of tetrachloropalladate to the vesicle bilayer, reduction of the palladium(II) to palladium(0), followed by the deposition of much larger amounts of metal from an electroless plating solution. Electroless plating solutions were used for the deposition of palladium, nickel, cobalt, or copper metal onto the catalytic palladium centers. Since the metallic particles were associated with the vesicles, colloids were formed that were stable in water for much longer periods than the control metal particles formed in water alone. If the vesicles were composed in part of unsaturated lipids, with the olefinic groupsmore » on the hydrocarbon chains, the initial evidence suggests the transition metal was directed into the bilayer, rather than staying on the surface.« less

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TL;DR: In this article, the surface roughness depends on the current density and electrodeposition time of the rhodium wire electrode and was determined by measuring the oxygen evolution currents at +1.6 V (vs. SCE) in 0.5 mol dm −3 H 2 SC 4.

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TL;DR: An electroplating method for the preparation of Co-Gd amorphous alloy films, which have recently attracted attention as materials for photo-magnetic memories, is described in this article.