Interlayer fabrication methods and interlayer structure are provided having reduced dielectric constants. The methods include, for example: providing a first uncured insulating layer with an evaporable material; and disposing a second uncured insulating layer having porogens above the first uncured insulating layer. The interlayer structure includes both the first and second insulating layers, and the methods further include curing the interlayer structure, leaving air gaps in the first insulating layer, and pores in the second insulating layer, where the air gaps are larger than the pores, and where the air gaps and pores reduce the dielectric constant of the interlayer structure.