Porphyrin Self-Assembled Monolayer as a Copper Diffusion Barrier for Advanced CMOS Technologies

• Published in: IEEE transactions on electron devices Vol. 59; no. 7; pp. 1963 - 1969
• Main Authors: Khaderbad, M. A., Pandharipande, R., Singh, V., Madhu, S., Ravikanth, M., Ramgopal Rao, V.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-07-2012; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Copper; Copper interconnect; Cross-disciplinary physics: materials science; rheology; Design. Technologies. Operation analysis. Testing; Dielectrics; diffusion barrier; Electronics; Exact sciences and technology; Integrated circuits; low- k interlayer dielectric (ILD); Materials science; Physics; Porous materials; granular materials; porphyrin; self-assembled monolayer (SAM); Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Silicon; Specific materials; Stress; Surface morphology; Surface treatment; Self-assembled layer; Interfacial layer; Performance evaluation; Atomic force microscopy; Voltage current curve; Barrier layer; Copper interconnect; High temperature; Porous material; Degradation; Complementary MOS technology; Humidity resistance; Stress effects; Fourier-transformed infrared spectrometry; Advanced technology; Copper; Low k dielectric; self-assembled monolayer (SAM); Voltage capacity curve; Damaging; porphyrin; Silsesquioxane polymer; Nanoindentation; Mechanical properties; Secondary ion mass spectrometry; Diamond; Contact angle; low-k interlayer dielectric (ILD); Zinc; Time of flight method; Integrated circuit; Dielectric thin films; Diffusion barrier; X-ray photoelectron spectra
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2012.2195184

This paper investigates properties of zinc porphyrin self-assembled monolayer (SAM) as a Cu diffusion barrier for advanced back-end complementary metal-oxide-semiconductor technologies. The SAM layers are integrated with various inter-layer dielectrics (ILDs) such as HSQ and black diamond (BD). Monolayer formation on ILDs was studied using X-ray photoelectron spectroscopy, atomic force microscopy, contact angle, FTIR, and UV-Vis techniques. Degradation study of the Cu/ILD and Cu/SAM/ILD systems was performed using stress-induced CV and IV at elevated temperatures. Time-of-flight secondary ion mass spectrometry was employed to establish effectiveness of these films as Cu diffusion barriers. The results indicate that SAM films, in addition to improving the ILD's moisture resistance, may help in thinning down the existing barrier layer thickness on the low-k porous ILDs. Effect of SAM layers on the mechanical properties of BD film was studied using nanoindentation.