Metallic Coatings

Krulik, G. A.; Mandich, N. V.

doi:10.1002/0471740039.vec1609

Cited by 3 publications

(6 citation statements)

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“…Krulik and Mandich [25] reported that the Au(I) thiosulphatesulphite mixed ligand system functions as an autocatalytic bath in the absence of any conventional reducing agent. They believed that the thiosulphate-sulphite mixture itself is a reducing agent system, and that sulphite functions as the main reducing agent in this bath.…”

Section: Introductionmentioning

confidence: 99%

Formulation and characterization of electrolyte for decorative gold plating based on mercaptotriazole

Dimitrijević

Rajčić-Vujasinović

Alagić

et al. 2013

Electrochimica Acta

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a b s t r a c tA procedure for the formulation and characterization of a gilding electrolyte based on mercaptotriazole is described. It was found that the electrolyte can be synthesized in a wide pH range, so solutions with different pH values (2, 4, 7, 9 and 12) have been prepared and analyzed. Inductively coupled plasma atomic emission spectroscopy and ultraviolet-visible spectroscopy were used for the chemical characterization of the prepared solutions. Electrochemical characterization is performed by open circuit potential measurement, cyclic voltammetry and polarization measurements.

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Section: Introductionmentioning

confidence: 99%

Formulation and characterization of electrolyte for decorative gold plating based on mercaptotriazole

Dimitrijević

Rajčić-Vujasinović

Alagić

et al. 2013

Electrochimica Acta

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“…The baths using hydrazine (22,23) and sodium hypophosphite (24) as the reducing agent were developed. More recently, it was reported that the deposition of gold in the thiosulfatesulfite mixed ligand system takes place autocatalytically even without adding any reducing agent (25). The present authors and collaborators have since conducted a detailed study on this aspect, which led to the conclusion that the bath without any added reducing agent functions as a substrate-catalyzed system rather than an autocatalytic system.…”

mentioning

confidence: 67%

“…The thiourea bath was developed and subsequently improved by a group of investigators at Hitachi, Ltd. (17,25). Basic and improved versions of the bath composition and operating conditions are shown in Table 2.…”

Section: Thiourea Bathmentioning

confidence: 99%

“…Currently, the improved bath is in large-scale commercial operation for plating contact terminals of printed circuit boards. Table 3 Basic and improved ascorbic acid baths (27) Figure 3 (25) reported that the Au(I) thiosulfatesulfite mixed ligand system functions as an autocatalytic bath in the absence of any conventional reducing agent. They believed that the thiosulfate-sulfite mixture itself is a reducing agent system, and that sulfite functions as the main reducing agent in this bath.…”

Section: Ascorbic Acid Bathmentioning

confidence: 99%

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Some recent developments in non-cyanide gold plating for electronics applications

Kato

Okinaka

2004

Gold Bull

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The plated gold being used by the electronics industry can be broadly classified into two categories: soft gold and hard gold. Soft gold is used for circuit metallization and for bonding semiconductor chips, while hard gold is indispensable as the contact material on electrical connectors, electromechanical relays, and printed circuit boards. The traditional baths from which to plate soft gold as well as hard gold contain the cyanide complex, [Au(CN)2] -, as the source of gold, which liberates free cyanide ions during the plating. The free cyanide is not only highly toxic but also attacks photoresists used to delineate circuit patterns and bonding pads. For these reasons, noncyanide baths are in use to plate soft gold, whereas hard gold can be plated only from cyanide baths at present. In this presentation, the current status of both electrolytic and electroless non-cyanide processes for plating soft gold will be reviewed.

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“…Baths Containing No Additional Reducing Agent Recently, Krulik and Mandich [83] discovered that the Au(I) sulfite-thiosulfate system functions as an autocatalytic gold plating bath without adding any conventional reducing agent. Such a bath was found to plate 0.03-0.3 mm of gold in 15min at pH 6.5-9.0 and 55-75 C directly on electroless nickel deposited on copper-clad epoxy glass laminated printed circuit board.…”

Section: Baths Containing Both Sulfite and Thiosulfatementioning

confidence: 99%

Electroless Deposition of Gold

Okinaka

Kato

2010

Modern Electroplating

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The term electroless plating was originally used by Brenner and Riddell [1], inventors of the well-known autocatalytic nickel and cobalt plating processes using hypophosphite as the reducing agent. A literature survey indicates, however, that this term is currently being used to describe three mechanistically different, nonelectrolytic processes for depositing metals and alloys: (1) galvanic displacement plating (also called immersion plating or cementation), (2) substrate-catalyzed plating, and (3) autocatalytic plating. In this chapter only autocatalytic gold plating processes are reviewed.The first autocatalytic, electroless gold plating bath was developed in 1970 at Bell Laboratories [1a] to plate thick, pure soft gold on semiconductors and circuit boards without employing an external source of electric current. The bath contained potassium cyanoaurate (I), KAu(CN) 2 , as the source of gold, potassium borohydride, KBH 4 , or dimethylamine borane, (CH 3 ) 2 NHÁBH 3 , as the reducing agent, potassium cyanide, and potassium hydroxide. Typical bath compositions are given in Table 21.1. The original baths did not contain stabilizing additives, and they were sensitive to minute amounts of impurities, which tended to lead to spontaneous decomposition. Nevertheless, those baths were employed successfully with sufficient stability under carefully controlled conditions [2-5], yielding highly pure, soft gold useful for the purpose of bonding semiconductor devices [6]. Other successful applications documented in the open literature include (1) metallization of GaAs microwave field-effect transistors [7], (2) formation of ohmic contacts consisting of Pd/Sn/Au films on n-GaAs [8], (3) metallization of polyvinylidene fluoride (PVDF) films used for making piezoelectric devices [9], (4) deposition of a conducting layer on the interior surface of waveguide tubes made of an aluminum alloy [10], and (5) deposition of a gold layer on tungsten-metallized ceramics for packaging semiconductor devices [11].More recently the accelerating trend of miniaturization and the need for greater reliability of electronic components have resulted in the development of new technologies for mounting devices on circuit boards, which in turn created new requirements for compatibility of the plating process with substrate materials and also for properties of gold films to be deposited on semiconductors and circuit boards. Quite generally, the method of electroplating has inherent advantages over that of electroless plating in terms of the ease of maintaining the bath and controlling the film thickness and properties. On the other hand, electroless plating has, in principle, a distinct advantage over electroplating in its capability of minimizing the number of processing steps when gold is needed in areas which are electrically isolated from each other. Under these circumstances, efforts have been made to improve the original borohydride and dimethylamine borane (DMAB) baths, especially in their stability and plating rate, and such improved baths are...

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Metallic Coatings

Abstract: Liquid‐Phase Metallizing Techniques Gas‐Phase Metallizing Techniques Vacuum‐Phase Metallizing Techniques Metallizing by Direct Physical or Thermal Bonding Environmental Concerns

Cited by 3 publications

References 1 publication

Formulation and characterization of electrolyte for decorative gold plating based on mercaptotriazole

Formulation and characterization of electrolyte for decorative gold plating based on mercaptotriazole

Some recent developments in non-cyanide gold plating for electronics applications

Electroless Deposition of Gold

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