A method for implementing a bismaleimide (BMI) polymer as a sacrificial material for an integrated circuit air gap dielectric. The method of one embodiment comprises forming a first and second metal interconnect lines on a substrate, wherein at least a portion of the first and second metal interconnect lines extend parallel to one another and wherein a trough is located between the parallel portion of said first and second metal interconnect lines. A layer of bismaleimide is spin coated over the substrate. The layer of bismaleimide is polished with a chemical mechanical polish, wherein the trough remains filled with the bismaleimide. A diffusion layer is formed over the substrate. The substrate is heated to activate a pyrolysis of the bismaleimide. An air gap is formed in the trough in the space vacated by the bismaleimide.