Soft gold electroplating from a non-cyanide bath for electronic applications

Wang, Kai; Beica, Rozalia; Brown, Neil

doi:10.1109/iemt.2004.1321669

Cited by 6 publications

References 10 publications

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Theoretical Study on the Adhesion Interaction between Epoxy Resin Including Curing Agent and Plated Gold Surface

et al. 2021

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In this study, the adhesive interaction between gold and epoxy resin is theoretically investigated. These materials make up crucial components of a wide range of electronic devices. The objectives of the study are (1) to elucidate the bonding mechanism between epoxy resin and a realistic gold surface, and (2) to obtain a device-design guideline for superior adhesion, thus reducing the bonding breakage that may potentially cause device failure. Die pad surfaces used in chip attachment methods for microelectronics are usually fabricated using an electrolytic plating technique. This technique involves ionic gold solutions like K[Au(CN) 2 ]. The combined theoretical and experimental studies previously carried out by the authors have revealed that the CN − counteranion of the gold cation has a high affinity for gold and is likely to remain on the realistic gold surface generated by plating. However, the cyano group content on the surface of the plated gold is still unknown. Therefore, gold surfaces embedded with cyano groups with various coverages are constructed. The effect of the varying coverage of the cyano groups on the adhesion strength is inspected using firstprinciples density functional theory calculations. As the number of cyano groups on the surface increases, the direct interaction between the gold surface and the epoxy resin is hindered, but the hydroxy and amino groups in the epoxy resin and hardener form more hydrogen bonds with the cyano groups adsorbed on the surface. It is found that the surface with intermediate cyano coverage (about 33%) yields the highest adhesive strength.

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Theoretical Study on the Adhesion Interaction between Epoxy Resin Including Curing Agent and Plated Gold Surface

et al. 2021

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A Novel Polishing Mechanism Used in Manufacturing Ultra-High Uniformity Gold Solder Bump

Huang

Chao

Hsu

et al.

2005 7th Electronic Packaging Technology Conference

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Effect of [Au]/[Na<inf>2</inf>SO<inf>3</inf>] molar ratio on co-electroplating Au-Sn alloys in sulfite-based solution

Qing

Huang

Pan

2009

2009 International Conference on Electronic Packaging Technology &Amp; High Density Packaging

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LEDs (Light Emitting Diodes) that assembled using flipchip technology are today used as long-life, energy efficient, environmentally friendly light sources. However, the flip chip solder joints have to meet high requirements. Therefore, their performance and quality are crucial for the integrity of the assembly, which in turn is vital to the overall function of the LED. Au-30at.%Sn eutectic alloy is the generally used solder in electro-optical assemblies due to its excellent thermal and mechanical properties. Au-Sn solder bumps can be obtained by sequential electroplating of Au and Sn layers or by coelectroplating Au-Sn alloys from a single solution. In the present work, Au-Sn alloys have been co-electroplated from a non-cyanide, sulfite-based stable solution which contains Na 3 Au (SO 3 ) 2 (gold sodium sulfite) as the source of gold and SnSO 4 (stannous sulfate) as the source of Sn. Na 2 SO 3 (sodium sulfite) is added as the complexing agent for gold and an additional commercial complexing agent for Sn. The effect of the [Au]/[Na 2 SO 3 ] molar ratio in the plating solution on the composition of the deposits, surface morphology and plating rate has been investigated. It was shown that the [Au]/[Na 2 SO 3 ] molar ratio of 1/24 proved to be the best one with respect to plating rate and surface morphology in the present experiment. When the Sn 2+ concentration is 0.03 mol/L, the optimum concentration for co-electroplating Au-Sn alloys is Au(I) concentration of 0.02 mol/L and Na 2 SO 3 concentration of 0.48 mol/L, corresponding to the [Au]/[Na 2 SO 3 ] molar ratio of 1/24. IntroductionLEDs, fabricated with III-V compound semiconductors, are capable of transforming electric energy into light energy with high efficiency and a life-span up to thousands of hours. In order to decrease the thermal resistance and improve heat transport away from the LED, flip chip technology has been developed to fabricate high-performance of LEDs. Thus bumping becomes a critical step in FC technology. The performance and quality of the solder bumps are crucial for the integrity interconnection, which in turn is vital to the overall function of the LEDs.As a joining material, solder provides electrical, thermal and mechanical continuity in electronics assemblies. Pb-Sn solders are well-known as the bumping material. However, with the increase of the environmental concerns, the use of lead free solders for electronic products has become a major driving force for technology developments [1,2]. The Au30at.%Sn alloy appears to be an attractive alternative, with a melting temperature of 280°C. Moreover, the Au-30at.%Sn alloy owns superior mechanical and thermal properties to conventional Pb-Sn solders, and have no negative effect on the environment.

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Soft gold electroplating from a non-cyanide bath for electronic applications

Cited by 6 publications

References 10 publications

Theoretical Study on the Adhesion Interaction between Epoxy Resin Including Curing Agent and Plated Gold Surface

Theoretical Study on the Adhesion Interaction between Epoxy Resin Including Curing Agent and Plated Gold Surface

A Novel Polishing Mechanism Used in Manufacturing Ultra-High Uniformity Gold Solder Bump

Effect of [Au]/[Na<inf>2</inf>SO<inf>3</inf>] molar ratio on co-electroplating Au-Sn alloys in sulfite-based solution

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