Extrusion Suppression of TSV Filling Metal by Cu-W Electroplating for Three-Dimensional Microelectronic Packaging

Abstract

Extrusion behavior of Cu filling in through-silicon-via (TSV) under thermal loading was investigated in this study. In order to suppress the extrusion of Cu-filled TSV, Cu-W was filled in a tapered TSV by electroplating. The Cu-filled TSV was used as a reference for comparison. Defect less filling of Cu-W in TSV was achieved at a composition 92.4 wt pct Cu and 7.6 wt pct W. The coefficients of thermal expansion of both Cu-7.6 pctW and Cu were 10.8 9 10 À6 /°C and 16.5 9 10 À6 /°C, respectively. Initially, both Cu and Cu-W filled TSVs were annealed for 30 minutes at 723 K (450°C) and the extrusion heights were measured. The results showed that the extrusion of Cu-W filled was suppressed significantly compared to Cu-filled TSVs. The annealed extrusion heights of Cu and Cu-W were found to be 1.369 and 0.465 lm, respectively. This showed around 34 pct lower extrusion height of Cu-W filled TSV as compared to Cu-filled TSV. The extrusion kinetics with different annealing durations and the mechanism of the suppression of extrusion in Cu-W filled TSV are also reported here.

Pulse Electrodeposition of Lead-Free Tin-Based Composites for Microelectronic Packaging

“…[57] In another study, the content can be SiC content increased up to 50 volume percent with a fluorocarbon surfactant. [42] Similar study shows that azocationic surfactant improved the incorporation rate up to 62.4 volume percent. [86] However, it is always recommended to use surfactants in a minute concentration in the plating bath to avoid carbon compounds in the coating.…”

“…[42] Recently, more attention has been paid to incorporate different nanoparticles to obtain much improved properties. There are various processing parameters in electrodeposition that affect the particle incorporation in composite deposits, such as (1) particle type, size, and shape; (2) bath pH, constituents, additives, and aging; (3) deposition variables, such as particle concentration in bath, current density, agitation, pulsing methods, and temperature.…”

“…There are various processing parameters in electrodeposition that affect the particle incorporation in composite deposits, such as (1) particle type, size, and shape; (2) bath pH, constituents, additives, and aging; (3) deposition variables, such as particle concentration in bath, current density, agitation, pulsing methods, and temperature. [42][43][44] The different nanocomposite solders produced in literature are shown in Table 1. The composite approach has been developed mainly to improve the strength and reliability of solder joints.…”

“…In few reports, there is a negligible effect of current density on the particle density in the matrix. [42,56] In other cases, various optimum particle concentrations have been detected in the current density versus particle concentration graph. [51,[57][58][59] It is also noteworthy point that the current density not only influences the codeposition rate, but the particles present in the electrolyte also modify the current density and hence the morphology of the deposits.…”

“…[71] Several reports are also available that show a linear decrease in the mass fraction of copper matrix composites as described in Ref. [42].…”