Fabrication of Ni Microbumps With Small Feature Size on Au Using Electroless Ni Plating With Noncontact Induction

Du, Yuxin; Song, Zhigong; Zhu, Huajun; Wang, Zheyao

doi:10.1109/tcpmt.2015.2448683

Cited by 4 publications

(2 citation statements)

References 24 publications

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“…The prepared bumps have a regular morphology, and there are no impurities and voids inside the bumps, which confirms that it is a feasible and practical approach [6]. Unfortunately, previous studies have not investigated the uniformity of bump arrays, and the existing studies on bump consistency have concentrated on large-feature-sizes and low-density bump arrays [3,4,7], leaving much space for exploration of small-dimension bump arrays with pith inside 10 μm. Besides, there are several urgent concerns during the fabrication process, such as skip plating, hydrogen bubble entrapment, and nodular growth, which will be discussed in detail in the subsequent chapter.…”

Section: Introductionmentioning

confidence: 59%

Electroless deposition of nickel microbumps for fine-pith flip-chip bonding

Lu,

Lin,

Wang

et al. 2024

J. Phys.: Conf. Ser.

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The reliability of micro-light-emitting diode (Micro-LED) is closely associated with the uniformity of microbumps arrays. With continual decreases in pixel pitch in recent years, it is a challenge to guarantee the uniformity of bump arrays. To satisfy current requirements for ultra-high-density interconnections, this study proposes an electroless plating method for fabricating highly uniform nickel microbumps. This technique differs from electroplating, in which the morphology and consistency of microbumps can be easily controlled. Furthermore, it is a high-selectivity and cost-effective method of microbumps fabrication that eliminates solder wastage and avoids metal lift-off in traditional evaporation. To minimize the non-uniformity of the bumps, we aim to optimize the oxygen plasma treatment parameters and deposition intervals to eliminate the issues of skip plating, hydrogen bubble entrapment, and nodules. Under the combined effect of plasma treatment and intermittent deposition method, microbump arrays with less than 5% uniformity were successfully prepared, achieving the demands of high-density bonding. In addition, the preparation process is highly reproducible, extending the application range of this technique.

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Section: Introductionmentioning

confidence: 59%

Electroless deposition of nickel microbumps for fine-pith flip-chip bonding

Lu,

Lin,

Wang

et al. 2024

J. Phys.: Conf. Ser.

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“…In [ 29 ] the negative effect of hydrogen on the quality of nickel columns formed for MEMS and CMOS integration is discussed. The additive, while inhibiting the bulk reaction, should not significantly affect the surface reaction.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and Characterization of Thin Metal Films Deposited by Electroless Plating with Organic Additives for Electrical Circuits Applications

Buylov,

Sotskaya,

Kozaderov

et al. 2023

Micromachines

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In our work, we studied thin nickel films deposited by electroless plating for use as a barrier and seed layer in the through-silicon vias (TSV) technology. El-Ni coatings were deposited on a copper substrate from the original electrolyte and with the use of various concentrations of organic additives in the composition of the electrolyte. The surface morphology, crystal state, and phase composition of the deposited coatings were studied by SEM, AFM, and XRD methods. The El-Ni coating deposited without the use of an organic additive has an irregular topography with rare phenocrysts of globular formations of hemispherical shape and a root mean square roughness value of 13.62 nm. The phosphorus concentration in the coating is 9.78 wt.%. According to the results of the X-ray diffraction studies of El-Ni, the coating deposited without the use of an organic additive has a nanocrystalline structure with an average nickel crystallite size of 2.76 nm. The influence of the organic additive is seen in the smoothening of the samples surface. The root mean square roughness values of the El-Ni sample coatings vary within 2.09–2.70 nm. According to microanalysis data the phosphorus concentration in the developed coatings is ~4.7–6.2 wt.%. The study of the crystalline state of the deposited coatings by X-ray diffraction made it possible to detect two arrays of nanocrystallites in their structure, with average sizes of 4.8–10.3 nm and 1.3–2.6 nm.

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