Method of forming an air gap using etch back of inter layer dielectric (ILD) with self-alignment to metal pattern

摘要

A method is disclosed of forming an air gap using etch back of an inter layer dielectric (ILD) with self-alignment to metal pattern. The method entails forming a first metallization layer deposited on a first dielectric, forming a second metallization layer deposited on a second dielectric, wherein the second metallization layer is spaced apart from the first metallization layer, forming a sacrificial ILD between the first and second metallization layers, forming a diffusion layer over the first and second metallization layers and over the sacrificial ILD, and removing the sacrificial ILD to form an air gap between the first and second metallization layers. This method is particular applicable for dual copper damascene processes.