Direct-Liquid-Evaporation Chemical Vapor Deposition of Nanocrystalline Cobalt Metal for Nanoscale Copper Interconnect Encapsulation

Abstract

In advanced microelectronics, precise design of liner and capping layers becomes critical, especially when it comes to the fabrication of Cu interconnects with dimensions lower than its mean free path. Herein, we demonstrate that direct-liquid-evaporation chemical vapor deposition (DLE-CVD) of Co is a promising method to make liner and capping layers for nanoscale Cu interconnects. DLE-CVD makes pure, smooth, nanocrystalline and highly conformal Co films with highly controllable growth characteristics. This process allows full Co 2 encapsulation of nanoscale Cu interconnects, thus stabilizing Cu against diffusion and electromigration. Electrical measurements and high-resolution elemental imaging studies show that the DLE-CVD Co encapsulation layer can improve the reliability and thermal stability of Cu interconnects. Also, with the high conductivity of Co, the DLE-CVD Co encapsulation layer can potentially further decrease the power consumption of nanoscale Cu interconnects, paving the way for Cu interconnects with higher efficiency in future high-end microelectronics.

From the source: student-centred guest lecturing in a chemical crystallography class

“…The focus placed on the 'source' of advanced crystallography techniques allows students to learn what crystallography can do for their research and to network with professionals who can potentially provide a valuable collaboration. Students are typically keen to take advantage of such resources once they become available and apply what they have learned to complete their research projects (Das et al, 2017;Feng et al, 2017;Hwang et al, 2015;Lou et al, 2016;Powers et al, 2013Powers et al, , 2016Powers, Anderson et al, 2014;Ramadhar et al, 2015aRamadhar et al, ,b, 2017. A list of example beam time proposals that students submitted for their own research projects at two major user research facilities can be found in Table S1 in the supporting information.…”

Effect of encapsulation on electronic transport properties of nanoscale Cu(111) films

“…In addition to graphene, the high electronic conductivity of Co (~1.61 × 10 7 S/m 36 ) has attracted a lot of attention as an encapsulating material for Cu interconnects. A recent study 6 has demonstrated that Co encapsulation stabilises Cu against diffusion and electromigration. As Co is a magnetic material, the lattice constant of ferromagnetic hcp (fcc) Co is 3.3% (2.4%) smaller than that of bulk Cu.…”

“…Among them, cobalt (Co) and Co alloys have emerged as promising candidates for complete encapsulation of advanced Cu interconnects 5 . Indeed, recent studies 6 have shown that smooth and highly conformal Co films can improve the reliability and thermal stability of Cu interconnects. Alternative to Co encapsulation, interesting research has also been conducted with graphene as an encapsulation material, where graphene is shown to be effective in reducing electromigration 7,8 .…”

Utilization of sodium silica from coal fly ash and trimethylchlorosilane as self-cleaning coating on glass

“…The coating processes of glass that are popularly used are Chemical Vapor Deposition (CVD), spray coating, spin coating, and dip coating. CVD method can produce a uniform layer [21], even so it needs a vacuum chamber that is difficult to handle. Thus, the dip-coating method is used because it can produce thin layers from chemical solutions with low-cost and waste-free processes [22].…”