Wafer level packaging is a particularly cost-effective method of producing chip-size packages, that is to say components of the size of a chip. These components are soldered or adhesively bonded onto the circuit board or the module board with the active side at the bottom by means of flip-chip technology, and are not further housed (chip on board). The contact elements used, which are called “bumps”, are in this case either rigid bumps (solder or gold bumps) or flexible, resilient polymer bumps (soft bumps), which are connected by cross-wiring to the connecting pads of the chip.
Within the context of wafer level packaging it is known to coat the rear of the wafer, on which the individual chips are formed, before the chips are separated by sawing up the wafer, in order in this way to protect the rear which, after the separated chips have been fitted to the circuit board or the module board, is exposed. This is advantageous in particular within the context of handling the chips when populating a circuit board or a module board, and even during the handling of the populated circuit board or the module board itself. However, from time to time damage occurs to the naked chip in the area of its chip side provided with the contact elements, said damage being disadvantageous and possibly leading to failure of a chip.