Study of low temperature MOCVD deposition of TiN barrier layer for copper diffusion in high aspect ratio through silicon vias

• Published in: Microelectronic engineering Vol. 120; pp. 127 - 132
• Main Authors: Djomeni, Larissa, Mourier, Thierry, Minoret, Stéphane, Fadloun, Sabrina, Piallat, Fabien, Burgess, Steve, Price, Andrew, Zhou, Yun, Jones, Christopher, Mathiot, Daniel, Maitrejean, Sylvain
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 25-05-2014; Elsevier
• Subjects: Applied sciences; Barrier; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Copper; Copper diffusion; Cross-disciplinary physics: materials science; rheology; Deposition; Design. Technologies. Operation analysis. Testing; Diffusion barriers; Electrical resistivity; Electronics; Exact sciences and technology; Flow rate; High aspect ratio; Integrated circuits; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Microelectronic fabrication (materials and surfaces technology); MOCVD; Physics; Precursors; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Silicon; Step-coverage; Through Silicon via (TSV); TiN; Vapor phase epitaxy; growth from vapor phase; Copper diffusion; Through Silicon via (TSV); TiN; Barrier; MOCVD; Step-coverage; Electrical conductivity; Barrier layer; Plasma assisted processing; Deposition process; Integrated circuits; Microelectronic fabrication; Manufacturing processes; Three dimensional structure; Wafers; Stress effects; Silicon; Copper; Diffusion; Uniformity; Low temperature; Densification; Titanium nitride; Spacing; Deposition rate; Interconnections; CVD; Diffusion barriers; Experimental design; Physicochemical properties; Via hole
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2013.11.010

•The MOCVD TiN films are N-riched.•Plasma treatment changes the films from amorphous to 7nm crystal grain size.•The films have larger gap in Ti and N concentration and contain less than 5% carbon.•The plasma densification lowers the carbon content down to 2%.•The step coverage is ⩾50% in 10×80μm TSVs sidewall.
This article is related to the development of a new low temperature CVD titanium nitride deposition process for the formation of a copper diffusion barrier in 3D TSV integration, using a metalorganic precursor and NH3.
The physicochemical properties of the film are studied on 300mm silicon wafers deposited using a SPTS Technologies Sigma300 fxP™ deposition equipment. A design of experiments (DoEs) was carried out at 200°C to check the influence of parameters such as reactor pressure, spacing (distance between the showerhead and the wafer), precursor/NH3 flow rate during deposition and NH3 flow rate during a subsequent densification plasma treatment. Responses including resistivity, uniformity, deposition rate and stress were measured. From this DoE, two process points are chosen according to expected material specifications requested from applications: a low resistivity process and a median conditions process. Then microstructure, the composition and stoichiometry of the film deposited with these process points are studied. Finally, the step coverage and continuity of the barrier in a high aspect ratio “through silicon via” (8:1, 10μm diameter etched in 80μm silicon) are measured and compared with a reference I-PVD process.