COMPOSITION ANALYSIS OF ECR-GROWN SIO2 AND SIOXFY FILMS

Low dielectric constant insulating films, such as SiO2 and fluorine do ped SiOx, are an important class of materials in semiconductor manufac turing. Evaluation of a new process to grow low temperature SiOxFy fil ms using an electron cyclotron resonance plasma (ECR) was done, Ion be am analysis techniques were used to characterize the compositions of t he insulating films and correlate this with their physical and electri cal properties. Since Si, O, F and H are of primary interest in these films, three different techniques were utilized in order to get a more thorough analysis. 2.8 MeV He Rutherford Backscattering Spectrometery (RBS) revealed the Si and O content, but because of the low fluorine concentrations [2-10 at.%) RBS proved difficult for analysis of the F content. Instead. Nuclear Reaction Analysis (NRA), which used 872 keV protons in the F-19(p, alpha gamma)O-16 reaction, was employed. Finall y, 30 MeV Si Elastic Recoil Detection (ERD) was used to obtain the H c oncentration and supplement the O analysis. The dielectric constant de creased from epsilon = 4 to epsilon = 3.55 as the F concentration incr eased from 0 to 10%.