Characterization of porosity and dielectric constant of fluorocarbon porous films synthesized by using plasma-enhanced chemical vapor deposition and solvent process

Abstract

Fluorocarbon films obtained in plasma-enhanced chemical vapor deposition with a C 4 F 8 compound were composed of a carbon cross-linked network and unlinked species encapsulated in the network ͓J. Appl. Phys. 89, 893 ͑2001͔͒. The unlinked species were effectively removed from the films. Then, the network probably containing the pore of the species was extracted on wafers when the films were dipped into tetrahydrofran ͑THF͒ solvent. The fact implied that fluorocarbon porous films with a low-dielectric constant might be formed by using dry and wet processes. In the present study, x-ray analyses showed that the THF-treated films actually became porous in the dipping process. The dielectric constant of the THF-treated films was consistently low (Ͻ1.9) and reduced by 10% from that of as-deposited films. The fluorocarbon network as a porous medium may be applied to interlayer dielectrics for ultralarge-scale integrated circuits.

Amorphous fluorocarbon polymer (a-C:F) films obtained by plasma enhanced chemical vapor deposition from perfluoro-octane (C8F18) vapor. II. Dielectric and insulating properties

“…They concluded that in such films ''an interconnected network of voids is present.'' Their observations are consistent with those of Takahashi et al 55 and Takahashi and Tachibana 56 who found that a-C:F films grown by PECVD from a C 4 F 8 monomer consist of a carbon cross-linked network and unlinked species encapsulated in the network. By using a dissolving technique that does not alter the film structure, they managed to obtain porous films with a pore size estimated to be a few subnanometers.…”

Plasma enhanced CVD of fluorocarbon films by low-pressure dielectric barrier discharge

“…Fluorocarbon (FC) films have been widely studied because of their remarkable properties, including a low dielectric constant (1.6-2.1) [1], biocompatibility [2,3], and superhydrophobicity [4,5]. Applications for such films include dielectric layers for the ultra-large scale integration devices, biopassivation coatings for implantable devices, and hydrophobic layers on paper.…”

Feasibility of using vanadium to form damascene structures with an air gap

“…According to the International Technology Roadmap for Semiconductors (ITRS) [1], however, ILDs with even lower dielectric constants are called for, and many studies [2,3,11,[14][15][16][17] have made efforts to further reduce the dielectric constants mainly by adjusting the porosity of films. In addition, some recent studies [18][19][20][21] proposed methods for utilizing air as ILDs.…”