Superfilling of Cu-Ag for metal interconnection was investigated in cyanide-based electrolyte. Superfilling was successfully achieved using the combination of KSeCN and thiourea. The trenches having widths in a range between 120 nm and 1.7 μm (depth: 400 nm) were filled without any voids. The continuous acceleration effect of KSeCN on Cu-Ag electrodeposition in the concentration range between 3.75 and 20 μM was confirmed, and thus the accumulation of KSeCN at the bottom of trench was surmised to be the main reason of Cu-Ag superfilling. Dissimilar to the previous superfilling of Ag or Au, which could be characterized as the fast surface diffusion of KSeCN, remarkable bumps and convex profiles at the corners of low-aspect-ratio trenches were developed. The proposed formula has led to defect-free superfilling of Cu-Ag with the Ag concentration in the range of 4.6 to 7.9 atom%.

Cu-Ag film could be a candidate to solve the reliability problem in semiconductor interconnection without severe increase in the resistivity. In this research, Cu-Ag film was successfully deposited in cyanide-based electrolyte using electrodeposition, and the effects of the electrolyte composition, applied potential, and the concentration of KAg(CN) 2 were researched. Prior to Cu-Ag electrodeposition, the conditions of Cu electrodeposition in cyanide-based electrolyte were precedently optimized in terms of the film resistivity. Ag was co-deposited in the film with an addition of KAg(CN) 2 in CuCN-based electrolyte, and the atomic concentration of Ag was successfully controlled by varying the concentration of KAg(CN) 2 . The film consisted of three phases; Cu (111), Ag (111), and the alloy. The resistivity of as-deposited Cu-Ag film was significantly higher than that of Cu; however, after annealing at 350 • C in an N 2 atmosphere for 1 hr, we obtained a resistivity comparable to that of Cu. The segregation of Ag atoms at the surface after the annealing was also confirmed, and it resulted in the increase in Ag atomic concentration at the surface and the reduction of surface roughness. Finally, it was confirmed that Cu-Ag film had superior oxidation resistance to Cu.

We developed a 1.0 nm thick aluminum oxide (Al2O3) interlayer as an electron blocking layer to reduce leakage current and suppress exciton quenching induced by charge imbalance in inverted quantum dot light emitting diodes (QLEDs).