Characterization of Mn-Based Self-Forming Barriers on Low-k Samples With or Without UV Curing Treatment

Area of Science:

• Materials Science
• Thin Film Technology
• Semiconductor Manufacturing

Background:

• Diffusion barriers are crucial for preventing interdiffusion between adjacent materials in microelectronic devices.
• Low-k dielectrics are increasingly used to reduce capacitance and improve device performance, but they present challenges for barrier integration.
• Self-forming barrier processes offer a potential solution for integrating barriers onto sensitive low-k dielectric surfaces.

Purpose of the Study:

• To investigate the efficacy of a copper-manganese (Cu-Mn) alloy as a material for self-forming diffusion barriers.
• To evaluate the impact of UV curing treatment on the diffusion barrier properties of the self-formed layer on low-k dielectrics.
• To compare the thermal stability of Cu-Mn/low-k dielectric interfaces with and without UV curing.

Main Methods:

• Co-sputtering of Cu alloy films with 3.8 at% Mn onto low-k dielectrics.
• Annealing of deposited films at various temperatures.
• Characterization of self-formed layers using transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS).
• Thermal stability measurements under various thermal stress conditions.

Main Results:

• A self-formed barrier layer was successfully created at the Cu-Mn alloy/low-k dielectric interface.
• UV curing treatment enhanced the formation of the diffusion barrier.
• Characterization revealed that UV curing altered the porosity and carbon concentration in the low-k dielectric layer, facilitating barrier formation.

Conclusions:

• Cu-Mn alloy is a viable material for self-forming diffusion barriers on low-k dielectrics.
• UV curing treatment is an effective method to improve the performance of these self-forming barriers.
• The enhanced barrier properties are attributed to UV-induced modifications in the low-k dielectric's physical and chemical characteristics.