SiCOH dielectric material with improved toughness and improved Si-C bonding, semiconductor device containing the same, and method to make the same

A method of fabricating a SiCOH dielectric material comprising:

• placing a substrate into a plasma enhanced chemical vapor deposition reactor;
• providing octamethyl-1,5-disiloxane-3,7-disilacyclooctane as a cyclic carbosilane precursor, a porogen, oxygen and helium to said reactor;
• depositing via plasma enhanced chemical vapor deposition a dielectric film derived from said cyclic carbosilane precursor onto said substrate, said plasma enhanced chemical vapor deposition includes a reactor pressure of 5 Torr, a flow of said cyclic carbosilane precursor and said porogen from 100 to 5000 mg/m, an O2 flow of 200 sccm, a helium flow of 2000 sccm, and applying an RF power of 500 W at a frequency of 13.6 to a showerhead of said reactor, wherein said dielectric film has a dielectric constant of 3.2 or less, at least atoms of Si, C, O, H and a covalently bonded tri-dimensional network structure in which some of the C atoms within said network structure are bonded as Si—CH3 functional groups, and some of the C atoms in said network structure are bonded as Si—CH2 —Si;
• and
• treating said deposited dielectric film using a combination of thermal energy and UV light energy.