RF SOI switches including low dielectric constant features between metal line structures

A method for fabricating a radio frequency (RF) silicon-on-insulator (SOI) switch on an SOI substrate such that said RF SOI switch includes first and second elongated spaced-apart source/drain regions separated by an elongated channel region, an elongated polycrystalline silicon (polysilicon) gate structure disposed over the channel region, at least two dielectric layers comprising one or more dielectric materials having a first dielectric constant disposed on an upper surface of the substrate, and a plurality of metal contact/via structures disposed in said at least two dielectric layers, the method comprising:

• forming a low dielectric constant (low-k) feature over said substrate in an associated interstitial region;
• forming a dielectric layer of said two or more dielectric layers including depositing one or more dielectric materials having a first dielectric constant into first and second reserved regions disposed on opposite sides of said interstitial region;
• and
• forming a plurality of periodically spaced metal structures that extend through said dielectric layer only in said first and second reserved regions such that each of said plurality of periodically spaced metal structures is entirely surrounded by said one or more dielectric materials forming said dielectric layer.