USING SMART DUMMY FILL AND SELECTIVE REVERSE ETCHBACK FOR PATTERN DENSITY EQUALIZATION

The existence of pattern effect in films polished by CMP processes has been well documented[5][6]. Large variations in effective pattern density have been shown to result in significant and undesirablepost-polish film thickness variation. To counteract this effect, two methods are typically used to equalizethe effective pattern density across the die. The first method is a process step known as reverse etchback,where areas of high density have large portions of the raised areas etched away, ...