A super low-k (k=1.1) silica aerogel film using supercritical drying technique

A porous silica aerogel film as low-k dielectric is demonstrated for the first time. An "on-wafer" gelation technique in ammonium hydroxide vapor is developed to enhance the process compatibility with the conventional spin-on dielectric process in ULSI technology. By using a supercritical drying process, which is free from capillary forces, a high porosity aerogel film with a k value of 1.1 is obtained.