Ken Sautter, KMS Enterprises, Stuart Allen & Bill Moffat, Yield Engineering Systems Inc., San Jose, CA, USA

ABSTRACT

In any robust microcircuit manufacturing environment, processes and equipment have to be decided on quickly, often too quickly for all the factors influencing the decision to be properly analyzed. One such process and piece of equipment is in the copper annealing area. This paper is an attempt to cover the process, physical and economic parameters that govern the decision to purchase a copper annealer. The traditional R&D unit, the hot plate, quickly moves to the vacuum hot plate. Then, as the process parameters for circuits with high aspect ratio trenches and problems with electromigration become apparent, a move to some batch process is indicated [1–4]. Further, problems with copper hillocks drive the annealing processes to longer times and possibly lower temperatures. As it was common to fight aluminum hillocks when we started aluminum multilayer metal, similar problems with copper processing should have been expected [5–7]. Problems with copper oxidation push for as low an oxygen concentration as possible [8, 9]. Problems with fluorine contamination determine the need for a totally moisture free environment [10]. Polymer voiding problems also point to a need for longer processing times and possibly some more forceful means of reducing or removing voids created during copper annealing [11, 12].