Improved uniformity of Ni/Au coating on circuits by electroless plating

Liu, Dongguang; Tian, Heng; Lin, Lijing; Shi, Wenchao

doi:10.1080/02670844.2018.1548537

Cited by 10 publications

(4 citation statements)

References 21 publications

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“…2b). 9,10,20,21 These features are confirmed by cross-section scanning ion microscope images obtained from the electroless-plated and electrolytic-plated PCBs (Figs. 2c and 2d, respectively), which were defined by a focus ion beam (FIB) technique.…”

Section: Resultssupporting

confidence: 60%

Effect of the Surface Morphology of Plated Printed Circuit Board on the Reliability of LED Packages

Kim

Song

et al. 2020

ECS J. Solid State Sci. Technol.

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We investigated the effect of the surface roughness of the differently plated printed circuit board (PCB) on the reliability of AlGaInP-based LED packages. The electroless-plated PCB exhibited smoother surface than the electrolytic-plated one. Maximum debonding forces depended on the aspect ratios of hillocks on the plated PCB and voids. Thermo-mechanical maximum stress increased with increasing roughness height. For LED packages with the electroless-plated PCB, thermal resistance (R th ) from junction to PCB was increased by 57.43 K W −1 after operation at 85 °C with 35 mA for 1000 h (reliability test), whereas for LED package with the electrolytic-plated PCB, R th from junction to PCB increased by 4.1 K/W. The temperatures of the chip areas of the electroless-plated and electrolytic-plated samples were 91.3 and 85.3 °C, respectively, after the reliability test. For the electroless-plated and electrolytic samples, the view angles along the X and Y axes were 144.43°and 142.87°, and 143.23°and 145.58°, respectively, after the reliability test. Unlike the electrolytic-plated samples, the electroless-plated samples experienced 4.8% drop in the lumen maintenance and delamination between the mold resin and PCB after operation under the 60 °C/90% relative humidity condition with 35 mA for 1000 h.

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Section: Resultssupporting

confidence: 60%

Effect of the Surface Morphology of Plated Printed Circuit Board on the Reliability of LED Packages

Kim

Song

et al. 2020

ECS J. Solid State Sci. Technol.

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“…Depositing palladium lm on copper circuits by galvanic replacement is commonly adopted as the activation process for PCB owing to the excellent activation ability of palladium [9] . However, because the copper circuit in PCB becomes ner and the space between copper circuits is narrower, it is easy to generate Ni-P coatings outside the copper circuits, that is, the phenomenon of over ow plating, resulting in PCB failure due to short circuits [10,11] . The reason is that the palladium activation process can lead to the activation of the polymer substrate between the copper circuits, and Ni-P coating will be deposited outside the copper circuits [12,13] .…”

Section: Introductionmentioning

confidence: 99%

Cobalt layer prepared on copper using galvanic replacement as an alternative to palladium for activating electroless Ni-P plating

Hu,

Li,

Liao

et al. 2024

Preprint

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Electroless nickel-phosphorus (Ni-P) plating is a widely used surface treatment method due to its excellent corrosion and wear resistance properties. However, the inertness of copper to hypophosphite oxidation necessitates a palladium activation process for the preparation of Ni-P coating on copper. In this study, we present a convenient approach for the deposition of a cobalt layer on copper using galvanic replacement, facilitated by the special complexing ability of iodide. The results demonstrated that the actual potential of copper could be adjusted to be lower than that of cobalt in a solution containing 8 mol/L NaI, enabling the deposition of a cobalt layer on copper in 15 minutes at 90°C. Furthermore, the deposition rate of the cobalt layer was found to increase with the concentration of CoCl2 in the NaI solution. Importantly, the Ni-P coating obtained through cobalt layer activation exhibited morphology, structure, and corrosion resistance, friction resistance similar to the Ni-P coating obtained using the common palladium activation. Therefore, the cobalt layer prepared on copper through galvanic replacement may serve as a viable alternative to palladium for activating electroless Ni-P plating.

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“…Compared with electroplating, ENIG plating can produce more uniform bumps since no external electricity is required. Furthermore, it has widespread applications in flip-chip bonding pads , and surface finish layers , because the ENIG layer exhibits excellent wear and corrosion resistance. More importantly, electroless plating is a promising way to achieve the vertical interconnection of chips in low temperature and pressureless condition. − Unfortunately, till now, no attention has been given to the electroless plating to produce bumps for micro-LED integration.…”

Section: Introductionmentioning

confidence: 99%

“…Compared with electroplating, ENIG plating can produce more uniform bumps since no external electricity is required. Furthermore, it has widespread applications in flipchip bonding pads16,17 and surface finish layers18,19 because…”

mentioning

confidence: 99%

Electroless Deposition of 4 μm High Ni/Au Bumps for 8 μm Pitch Interconnection

Tian

Lin

Pan

et al. 2022

ACS Appl. Electron. Mater.

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We propose that electroless plating is a superb approach to preparing metallic bumps with an ultrafine pitch for the integration of a micro light-emitting diode (micro-LED). Electroless plating does not suffer from lift-off-related issues, which are ubiquitous in thermal evaporation. Besides, it can result in much more uniform bumps than electroplating because the bump height is not affected by the current distribution. This study reports ultrafine pitch Ni/Au bumps fabricated by electroless nickel immersion gold (ENIG) plating. Furthermore, cheap metals iron and nickel are selected to catalyze the electroless nickel process. The results indicate that uniform and consistent Ni/Au bumps can be obtained through the iron sheet and nickel layer method. Besides, no voids and impurities are found inside the bumps, which is beneficial for the following interconnection process. Moreover, the change in Ni bump height values with the electroless plating time is also provided.

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Improved uniformity of Ni/Au coating on circuits by electroless plating

Cited by 10 publications

References 21 publications

Effect of the Surface Morphology of Plated Printed Circuit Board on the Reliability of LED Packages

Effect of the Surface Morphology of Plated Printed Circuit Board on the Reliability of LED Packages

Cobalt layer prepared on copper using galvanic replacement as an alternative to palladium for activating electroless Ni-P plating

Electroless Deposition of 4 μm High Ni/Au Bumps for 8 μm Pitch Interconnection

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