Air gaps between conductive lines for reduced RC delay of integrated circuits

A method of forming insulating regions between conductive lines of a semiconductor device, the method comprising:

• providing a workpiece, the workpiece comprising a first region and a second region;
• forming a plurality of conductive lines over the workpiece in the first region and the second region, wherein a first insulating material is disposed between the plurality of conductive lines in at least the first region of the workpiece and a second insulating material overlies at least the first insulating material;
• forming an energy insensitive insulating material between the plurality of conductive lines in the second region,
• exposing the workpiece to energy, wherein exposing the workpiece to energy comprises exposing both the first and the second region of the workpiece to energy;
• and
• removing at least a portion of the first insulating material in the first region between the plurality of conductive lines through the second insulating material;
• and
• wherein forming the plurality of conductive lines over the workpiece in the first region and the second region comprises:
• depositing a conductive material over the workpiece;
• and
• patterning the conductive material to form the plurality of conductive lines in the first region and the second region.

A method of forming insulating regions between conductive lines of a semiconductor device, the method comprising:

• providing a workpiece, the workpiece comprising a first region and a second region;
• forming a plurality of conductive lines over the workpiece in the first region and the second region, wherein a first insulating material is disposed between the plurality of conductive lines in both the first region and the second region of the workpiece and a second insulating material overlies at least the first insulating material, and wherein the first insulating material comprises an energy-sensitive material;
• exposing the workpiece to energy, wherein exposing workpiece to energy comprises exposing the second region, but not the first region, to the energy;
• and
• removing at least a portion of the first insulating material between the plurality of conductive lines through the second insulating material.