Surface Modification by Plasmas: X-ray Photoemission Studies

Abstract

Submicrometer dimension multilevel metallization schemes and ultra-large scale integration requires plasma based reactive ion etching pattern transfer. Crystalline damage (1) and residue layers (2-4) in small area contacts can produce high resistance contacts as the structural dimensions are reduced in size. During reactive ion etch patterning, the silicon surface is subjected to ion bombardment which produces crystalline damage and amorphization of the near surface region (4). The surface is also damaged by the formation of thin films of species which condense out of the plasma. This residue layer, which forms from the extinguishing plasma, is chemically dependant upon the plasma composition, vacuum system and substrate geometry and material. For example, fluorocarbon based reactive ion etching can leave fluoropolymer residue films (5,6).