Uniformity of an Electroless Plated Ni on a Pad Connected to Different Size Pads or a Pn Junction for Under Bump Metallurgy in a Flip-Chip Assembly

Ikeda, Akira; Saeki, Tsubasa; Sakamoto, Atsushi; Sugimoto, Yoshiki; Kimiya, Y.; Fukunaga, Yusuke; Hattori, Reiji; Kuriyaki, Hisao; Kuroki, Yoshio

doi:10.1109/tcapt.2007.901675

Cited by 6 publications

(2 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The electron migration at the surface is determined by photovoltage for p-n junctions and electronegativity of the substrate [48]. Significant variation in the plating rates for n-type substrates under illumination has been observed [48,49]. The photogenerated electrons which diffuse to the surface can contribute to reduction of Ni 2+ and hence increase the plating rate [48].…”

Section: Photoassisted Electroless Ni Platingmentioning

confidence: 99%

Review of Ni-Cu Based Front Side Metallization for c-Si Solar Cells

Raval

Solanki

2013

Journal of Solar Energy

View full text Add to dashboard Cite

Given the high percentage of metal cost in cell processing and concerns due to increasing Ag prices, alternative metallization schemes are being considered. Ni-Cu based front side metallization offers potential advantages of finer grid lines, lower series resistance, and reduced costs. A brief overview of various front side patterning techniques is presented. Subsequently, working principle of various plating techniques is discussed. For electroless plated Ni seed layer, fill factor values nearing 80% and efficiencies close to 17.5% have been demonstrated, while for Light Induced Plating deposited layers, an efficiency of 19.2% has been reported. Various methods for qualifying adhesion and long term stability of metal stack are discussed. Adhesion strengths in the range of 1–2.7 N/mm have been obtained for Ni-Cu contacts tabbed with conventional soldering process. Given the significance of metallization properties, different methods for characterization are outlined. The problem of background plating for Ni-Cu based metallization along with the various methods for characterization is summarized. An economic evaluation of front side metallization indicates process cost saving of more than 50% with Ni-Cu-Sn based layers. Recent successful commercialization and demonstration of Ni-Cu based metallization on industrial scale indicate a potential major role of Ni-Cu based contacts in near future.

show abstract

Section: Photoassisted Electroless Ni Platingmentioning

confidence: 99%

Review of Ni-Cu Based Front Side Metallization for c-Si Solar Cells

Raval

Solanki

2013

Journal of Solar Energy

View full text Add to dashboard Cite

show abstract

“…Similarly, our choice of feature line dimensions is dictated by eq , with the goal of providing Cu features ideally exhibiting identical electrical conductivities (vide supra). In addition, although plating dependencies on feature spacing can occur for sub-micrometer features, where diffusion effects and anomalies become important, − such effects are typically not observed for the macroscopic features and line spacings selected for study here. Therefore we expect the (1/ R ) to be independent of both L and S , as confirmed by our analysis and model.…”

Section: Resultsmentioning

confidence: 99%

Statistical Analysis of Plating Variable Effects on the Electrical Conductivity of Electroless Copper Patterns on Paper

Zabetakis

Dressick

2012

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

We describe a process for selective metallization of paper substrates bearing inkjet printed patterns of a commercial Pd/Sn colloidal catalyst ink plated using a commercial electroless Cu bath. The electrical conductivity of the Cu films is analyzed as a function of feature geometry (line dimensions (L) and spacing (S)), type of paper (P), age of the Pd/Sn patterns (A), plating time (T), and plating temperature (H) using a two-level factorial design. Conductivity is influenced predominantly by the P, T, and H factors, with lesser contributions attributed to pair-wise interactions among several of the variables studied. Increases in T and/or H enhance conductivity of the Cu films, whereas increases in P, corresponding to the use of rougher, more porous, paper substrates, yield Cu films exhibiting decreased conductivity. Our analysis leads to a model that predicts Cu film conductivity well over the ranges of variables examined, provides guidelines for identification of optimum conditions for plating highly conductive Cu films, and identifies areas for further process improvement.

show abstract