Multilevel Metallization of High-Temperature Silicon IСs Based on Tungsten. Physics and Technology: A Review

Currently, increasingly stricter requirements are being imposed on the functional nodes of ICs. One of these requirements is interconnection metallization. The use of ordinary metals cannot fully ensure the operation of devices at temperatures of 200°C and above. Therefore, refractory metals such as tungsten are of interest. Tungsten is characterized by increased electromigration resistance; however, it is a brittle and rigid material, which leads to low adhesive ability to silicon and silicon oxide, as well as cracking of the material. This reduces the efficiency of its use for IC interconnection metallization. In this study, based on the analysis of the literature, it is shown that the addition of rhenium to tungsten ensures the production of yielding conductive interconnections characterized by satisfactory adhesive ability. It is established that titanium and nitrogen have an effect similar to rhenium. These materials also reduce mechanical stresses in tungsten films and increase their adhesive ability. The results of an analysis of the published sources suggest that the interconnections based on tungsten with various dopants such as rhenium, titanium, and nitrogen can be used as functional material in high-temperature electronics.