Before revision: A WL-CSP or WLCSP package is just a bare die with a redistribution layer (RDL, interposer or I/O pitch) to rearrange the pins or contacts on the die so that they can be big enough and have sufficient spacing so that they can be handled just like a ball grid array (BGA) URL
After revision: A WL-CSP or WLCSP package is just a bare die with a redistribution layer (RDL, interposer or I/O pitch) to rearrange the pins or contacts on the die so that they can be big enough and have sufficient spacing so that they can be handled just like a ball grid array (BGA) package.