Sputter deposited barrier layers

Abstract

The present disclosure pertains to our discovery that depositing various film layers in a particular order using a combination of Ion Metal Plasma (IMP) and traditional sputter deposition techniques with specific process conditions results in a barrier layer structure which provides excellent barrier properties and allows for metal/conductor filling of contact sizes down to 0.25 micron and smaller without junction spiking. Specifically, the film layers are deposited on a substrate in the following order: (a) a first layer of a barrier metal (M), deposited by IMP sputter deposition; (b) a second layer of an oxygen-stuffed barrier metal (MOx), an oxygen-stuffed nitride of a barrier metal (MNOx), or a combination thereof; (c) a third layer of a nitride of a barrier metal (MNx), deposited by IMP sputter deposition of the barrier metal in the presence of nitrogen; and (d) a fourth, wetting layer of a barrier metal, deposited by traditional sputter deposition. The first layer of barrier metal can optionally be annealed to form a silicide of the barrier metal (MSi2) in order to reduce contact resistance and interdiffusion of the silicon and metal/conductor which may result form overetching of contacts. An additional layer of barrier metal can optionally be deposited between the second oxygen-stuffed layer and the third barrier metal nitride layer in order to further improve the barrier properties of the barrier layer structure and to provide for better metal/conductor fill. A thin layer of metal/conductor may be deposited on the walls of the contact via by “long throw” sputter deposition prior to filling the via with metal/conductor in order to provide more uniform fill. The optimum process conditions for sputter deposition of the barrier layer structure of the invention are disclosed herein.

Dependencies are inferred from the claim text.