Investigation On Distribution Of Fluorocarbon Plasma Radicals And Its Effect On Bond Configuration Of Fluorinated Amorphous Carbon Films

As one of promising interlay dielectrics used in the future ULSI, fluorinated amorphous carbon film (a-C: F) has been attracted intensively. All kinds of techniques for the deposition of a-C: F films were introduced. Many studies on electrical property, thermal stability, etc for the a-C: F films were carried out. However, few reports on the correlation between the plasma behavior and film properties were made. In this thesis, we have mainly studied the characteristics of CHF3, C6H6 and CF4 electron cyclotron resonance (ECR) plasma using Langmuir probe and optical emission spectroscopy (OES). The relative concentration of different radicals in CHF3 plasma and the effect of CHF3/C6H6 ratio on bond configuration of a-C: F films were discussed.It was showed that H, F, C2 were the main radicals among radicals of H, F, C2, CH and F2 in CHF3 ECR plasma. The relative concentration of H, F and C2 increased with the increasing input microwave power. For the discharge pressure from 0.15 Pa to 0.9 Pa, the relative concentration of all these radicals increased initially and then decreased as the pressure was larger than 0.65Pa. Detailed analysis showed that C2 radicals came from a chemical reaction between H or F atoms and fluorocarbon film deposited on the chamber surface. The relative concentration of CF CF2 C2 radicals increased with the increasing of CHF3/C6H6 ratio, while the deposition rate of a-C:F film showed a decreasing trend. This result strongly suggested that the C-F relative intensity in a-C: F film is closely related to the relative concentration of F atoms in the ECR plasma.