In wafer-level chip-scale packaging (WLCSP) technology, the
"package", or interconnect elements, are fabricated on the wafer
prior to singulation. This makes it different from all other package
types in that there is no assembly to a substrate, and the
singulated WLCSP is ready for SMT mounting. The area it occupies
when mounted onto a printed circuit board is the size of the die.
The greatest benefits of WLCSPs are the true chip-size product
and the relative cost of wafer-level processing. All devices
on a wafer are processed and and tested together in wafer form and
later singulated into individual chips. Like wafer fabrication, the
cost of the WLCSP goes down as the wafer size increases and as the
die shrinks.
