Evaluation of a novel unfluorinated copper precursor for chemical vapor deposition

• Published in: Microelectronic engineering 2010-03, Vol.87 (3), p.249-253
• Main Authors: Song, Haizheng, Norman, John A.T., Shimogaki, Yukihiro
• Format: Article
• Language: English
• Subjects: Applied sciences; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: structure, mechanical and thermal properties; Copper CVD; Cross-disciplinary physics: materials science; rheology; Design. Technologies. Operation analysis. Testing; Electronics; Exact sciences and technology; High-pressure and shock-wave effects in solids and liquids; Integrated circuits; Kinetic analysis; Materials science; Mechanical and acoustical properties of condensed matter; Metallization; Methods of deposition of films and coatings; film growth and epitaxy; Microelectronic fabrication (materials and surfaces technology); Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Unfluorinated precursor
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2009.07.017

A kinetics of the chemical vapor deposition (CVD) of copper using novel unfluorinated precursor, copper(I)(N(1(dimethylvinylsiloxy)-1-methylethano)-2-imino-4-pentanoate), namely Cu-KI5, was studied. Since its great thermal stability, Cu-KI5 allowed high source temperature to provide high vapor pressure, for example Cu-KI5 has a vapor pressure of 0.2–2.2 Torr at the temperature range of 100–140 °C. Furthermore, copper could be deposited by direct reduction from Cu-KI5 instead of disproportionation. By using formic acid (HCOOH) as a reducing agent, copper films were deposited on ruthenium substrate at temperature range of 150–350 °C. The activation energy was 48.9 kJ/mol in surface reaction limited region (210 °C) at the total pressure of 5 Torr. Secondary ion mass spectroscopy (SIMS) analysis showed that CVD copper film of high purity (>99.99%) was deposited at 250 °C. The as-deposited copper films grown at 150–300 °C exhibited strong 〈111〉 preferred orientation. The minimum resistivity of the copper film was 1.77 μΩ cm obtained at the deposition temperature of 250 °C. In the surface reaction limited region, kinetic data extracted from experiments enabled 2-D computational simulation to predict copper deposition into trench structures. Simulation results showed excellent step coverage, which was larger than 90% for aspect ratio of 10:1. Cu-KI5 is a promising Cu-CVD precursor for the fabrication of ultra large scale integration (ULSI) or through silicon via (TSV) copper interconnects.