Atomic layer deposition of insulating alf3/polyimide nanolaminate films

Abstract

This article describes the deposition of AlF3/polyimide nanolaminate film by inorganic-organic atomic layer deposition (ALD) at 170 °C. AlCl3 and TiF4 were used as precursors for AlF3. Polyimide layers were deposited from PMDA (pyromellitic dianhydride, 1,2,3,5-benzenetetracar-boxylic anhydride) and DAH (1,6-diaminohexane). With field-emission scanning electron micros-copy (FESEM) and X-ray reflection (XRR) analysis, it was found that the topmost layer (nominally 10 nm in thickness) of the nanolaminate film (100 nm total thickness) changed when exposed to the atmosphere. After all, the effect on roughness was minimal. The length of a delay time between the AlF3 and polyimide depositions was found to affect the sharpness of the nanolaminate structure. Electrical properties of AlF3/polyimide nanolaminate films were measured, indicating an increase in dielectric constant compared to single AlF3 and a decrease in leakage current compared to poly-imide films, respectively.