Amorphous Ta_xMn_yO_z Layer as a Diffusion Barrier for Advanced Copper Interconnects

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanotechnology

Background:

• Advanced interconnects require robust diffusion barriers to prevent copper migration.
• Thin film stability and adhesion are critical for device reliability.

Purpose of the Study:

• To investigate the efficacy of a 1.0-nm-thick amorphous Ta_xMn_yO_z layer as a copper diffusion barrier.
• To evaluate the thermal and electrical stability of this novel barrier material.

Main Methods:

• Transmission electron microscopy (TEM) for microstructural analysis.
• X-ray photoelectron spectroscopy (XPS) for chemical characterization.
• Current density-electric field (J-E) and capacitance-voltage (C-V) measurements for electrical stability.
• Tape peeling test for adhesion assessment.

Main Results:

• The Ta_xMn_yO_z barrier demonstrated excellent adhesion between copper and SiO₂ layers.
• TEM and energy-dispersive X-ray spectroscopy confirmed the prevention of copper diffusion after annealing at 400°C for 10h.
• J-E and C-V measurements indicated significantly improved electrical stability of the copper interconnect.
• The ternary Ta-Mn-O film's microstructural stability, influenced by the Ta/Mn atomic ratio, is key to its performance.

Conclusions:

• The 1.0-nm-thick amorphous Ta_xMn_yO_z barrier is a highly effective solution for preventing copper diffusion.
• This material enhances both thermal and electrical stability in advanced interconnects.
• The controlled ternary composition offers a promising pathway for next-generation interconnect technology.