摘要
Carbon doped oxide (SiOC:H) low k films have been prepared by a high density plasma chemical vapor deposition system using mixtures of trimethylsilane and oxygen. The SiOC:H films are etched by ICP-RIE system with CF4/O2 gas mixtures. The films have been characterized by Fourier transform infrared spectroscopy and cross section images of the thin films were obtained by scanning electron microscopy (SEM). Etch rates were calculated from the etched film thickness and etch time. The electrical properties of the films have been measured using metal-insulator-silicon structures. Dielectric constant of as-deposited film is 2.2, which is as low as porous silica films. CF4/O2 plasma was used to etch SiOC:H films. Dielectric constant of etched SiOC:H film is 4.94 due to damage and reaction during etching process. Annealing treatment is used to improve the dielectric constant of etched SiOC:H films. After annealing for 30 min and 60 min, dielectric constant reduces to 2.55 and 2.56, respectively. In summary, sharp etching profile is obtained by optimal CF4/O2 plasma mixture, and the electrical and physical properties of etched SiOC:H thin films can be further improved by thermal treatment. So, it can be integrated into ULSI interconnect system by optimum etch condition. © 2005 Materials Research Society.