Real-time die shift correction
The elimination of the substrate in fan-out packaging is key to cost reduction and slim form factor. To facilitate the removal of the substrate, epoxy mold compound is used to reconstitute known good die. Both pressure and heat are used in the molding process after pick and place. In all cases, this process causes the placed die to shift and the reconstituted substrate to warp.
Rudolph's inspection, metrology, lithography, and advanced software are combined to dynamically measure and adjust for this shift, whether working on wafers or panels, to help ensure overlay specifications are met and subsequent RDL layers are imaged correctly.