Development of different copper seed layers with respect to the copper electroplating process

Two types of copper seed layers deposited by MOCVD and long throw sputterin g (LTS) onto a tantalum barrier layer were used for electroplating (EP) of copper in the forward pulsed mode. MOCVD and PVD copper seed layers were co mpared with respect to step coverage, electrical resistivity, texture and a dhesion behaviour. The different properties induce different electroplating fill attributes, including grain size and adhesion behaviour. MOCVD Cu see d layers show high step coverage, but do not adhere to the Ta barrier after the Cu EP. LTS Cu reveal strong (111) texture and excellent adhesion befor e and after Cu EP. Therefore, a CMP process could only be performed on patt erned wafers with PVD/EP copper to obtain electrical data. The fabricated C u lines show a high yield with respect to opens and shorts and standard dev iations of the line resistance across the wafer. (C) 2000 Elsevier Science B.V. All rights reserved.