Diffusion Barriers for Cu
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
Ta, TiN and Si3N4 are found to be good diffusion barriers to Cu without degradation of its resistance. Combinations of one or two of these materials can be deposited to encase Cu lines using processes compatible with VLSI processing. Cu is a material of high potential for VLSI metallizations due to its better conductivity, better electromigration resistance, and smaller power consumption than Al. As the device dimensions are continually scaling down, the switching speed in the chip is mainly limited by the RC time delay which is associated with interconnections. For these reasons, the use of Cu metallizations in VLSI becomes more important than before. Cu is a fast diffuser into SiO2 and Si. In order to prevent Cu contamination of the devices, both insulator and metal dif fusion barriers for Cu must be found.