Abstract

The increasing challenge in reducing the vertical dimension in modern VLSI. A multilayer metallization system has been used conventionally. It comprises three parts, Al used as a last layer to offer electrical interconnects, the metalloid silicide chosen as ohmic contact to Si, an intermediate layer inserted between them as diffusion barrier. So-called nitrides of transition metal may be suggested as suitable diffusion barrier,/1/ as we know, TiN film can be produced by nitrogen ion implanted onto evaporated Ti film and formed during nitrogen annealing of magnetron sputtered Ti film /2/ or nitrogen ion implanted and annealed TiN film with a thermal treatment by an electron beam /3/. However, a suitable TiN diffusion barrier layer, as most previous papers have reported, either a relative high annealing temperature or longer enough treating time was required. We describe here a new method of TiN film on crystalline Si and SiO₂ substrate respectively using a wide area electron beam. The Ti film was deposited in a standard vaccum system, the thickness of Ti film was 1000 Å. The rapid nitride processing was performed by a large area plasma electron beam, the cross section of electron beam is 50 mm in diameter and the uniformity better than 4% over cross section of EB. It was operated in 10°–10⁻² Torr of N₂ and He gas enviroment. In experiment, the processing time, ratio of the mixture of N₂ and He, the pressure and flow rate of gases and power density of EB were varied. After 5-50 seconds nitridation processing TiN were formed, the surface of thin film turned gold like colour.

© 1987 Optical Society of America