Enhancement of Selective Chemical Vapor Deposition of Copper by Nitrogen Plasma Pretreatment

Abstract

Selective chemical vapor deposition of copper on TiN in the presence of borophosphosilicate glass (BPSG) was achieved by RF N2 plasma pretreatment. Without N2 plasma pretreatment, the copper films deposited on BPSG as well as TiN at the deposition temperature of 170°C, while N2 plasma treatment prior to copper deposition led to the significant suppression of the copper nucleation on BPSG. As the plasma pretreatment temperature was increased, the suppression of the copper nucleation on BPSG was increased. The results of time-of-flight secondary ion mass spectroscopy (TOF-SIMS) indicated that N2 plasma treatment decreased the content of hydroxyl groups on BPSG surface, suggesting that the reduction of the surface hydroxyl groups contributed to the selective deposition of copper on TiN/BPSG substrates.