Deliberate void in innerlayer dielectric gapfill to reduce dielectric constant

A method of forming an innerlayer dielectric having a dielectric constant of about 1, comprising:

• providing a semiconductor substrate having at least two metal lines thereon;
• providing a conformal silicon nitride layer over the substrate and metal lines, the conformal silicon nitride layer having a substantially uniform thickness from about 1,000 Å to about 3,000 Å;
• forming a first insulation layer over the conformal silicon nitride layer, the first insulation layer comprising a void positioned between two metal lines, the void comprising an inert gas and the first insulation layer comprising at least one of silicon dioxide, fluorine doped silicon glass, tetraethylorthosilicate, phosphosilicate glass, borophosphosilicate glass, and a low K polymer material;
• at least one of thinning and planarizing the first insulation layer;
• and
• forming a second insulation layer having a thickness from about 2,500 Å to about 10,000 Å over the first insulation layer.

An innerlayer dielectric semiconductor structure, comprising:

• a semiconductor substrate having at least two metal lines thereon;
• a conformal insulation layer over the semiconductor substrate and metal lines, the conformal insulation layer comprising silicon nitride and having a substantially uniform thickness from about 1,000 Å to about 5,000 Å;
• a second insulation layer comprising silicon dioxide over the conformal insulation layer, the second insulation layer comprising a void positioned between two metal lines, the void comprising an inert gas;
• and
• a third insulation layer comprising tetraethylorthosilicate over the second insulation layer.

An innerlayer dielectric semiconductor structure, comprising:

• a semiconductor substrate having at least two metal lines thereon;
• a conformal silicon nitride layer over the semiconductor substrate and metal lines, the conformal silicon nitride layer having a substantially uniform thickness from about 1,000 Å to about 3,000 Å;
• a first insulation layer over the conformal silicon nitride layer, the first insulation layer comprising a void positioned between two metal lines, the void comprising an inert gas and the first insulation layer comprising at least one of silicon dioxide, fluorine doped silicon glass, tetraethylorthosilicate, phosphosilicate glass, borophosphosilicate glass, and a low K polymer material;
• and
• a second insulation layer having a thickness from about 2,500 Å to about 10,000 Å over the first insulation layer.