A dielectric material is provided having air gaps which form during dielectric deposition between horizontal or vertical spaced conductors. The dielectric is deposited upon a polyimide, wherein the polyimide is placed over and between an underlying level of conductors. As the overlying...http://www.google.de/patents/US5783481?utm_source=gb-gplus-sharePatent US5783481 - Semiconductor interlevel dielectric having a polymide for producing air gaps 
