BASIC PROBLEMS IN INTERCONNECT METALLIZATION FOR VLSI APPLICATIONS.

The aim of this paper is to examine the basic problems in interconnect for VLSI applications. First the nature of the problem is explored by projecting the future demands, based on the trend of device scaling, on the fundamental requirements of the interconnects. This brings into focus three key areas of concern: junction contacts, electromigration and wiring complexity. The first two are directly related to material properties, therefore, the discussion is focused on problems in metallization arising from device performance and reliability requirements. In contrast, interconnect wiring concerns statistical optimization of a complex system and not directly related to metallization. The origin of the wiring complexity and its implication on VLSI interconnect structure are discussed. Finally, an attempt is made to assess the current developments in meeting these challenging problems.