600MM Wafer-Level Fan Out on Panel Level Processing with 6-Sided Die Protection

Abstract

300mm carrier wafer for Fan-Out Wafer Level Packaging (FOWLP), is currently the mainstream format used for PMICs, RF and other single die applications. As volume of these devices continue to ramp up, the 300mm medium used for Fan-Out processing continues to stay the same. The need for migrating to panel sizes larger than 300mm becomes a necessity to lower down costs and handle higher volumes. The fastest adoption of Fan-Out technology is now in 5G, automotive and healthcare. Traditional applications such as audio codecs, PMICs, microcontroller units (MCU) and radio frequency (RF) continue to use Fan-Out Wafer Level Packaging (FOWLP) as an alternative to Wafer Level Chip Scale packaging (WLCSP) due to its 5 -sided or 6-sided die protection. As Fan Out packaging becomes mainstream and to get broader adoption of Fan-Out, the need for driving down the cost continues to be at the forefront of Fan-Out suppliers. 600mm × 600mm format utilized in this study leverages existing backend processing equipment used on 200mm and 300mm wafers for cost savings. Utilizing existing equipment would enable the panel to be singulated into 4 × 300mm or 9 × 200mm square segments to enable probe testing. Coupling the 6-sided die protection process (M-Series) with 600mm × 600mm panel level processing paves the way for innovative methods for Fan-Out processing. New photolithography processing utilizing laser direct imaging (Adaptive Patterning ™) to auto scale for die shift mitigation, is heavily dependent on segmentation of the panel. In this instance, the 600mm panel is either segmented into 4 × 300mm, 9 × 200mm or l×600mm for Photolithography steps. Depending on the number of fiducials used during the photolithography steps, capital expenditure and exposure accuracy would be highly dependent on the segmentation chosen. In addition, new metrology tools and panel warpage management will need to be considered for quality assurance. This paper will present a case study of utilizing 600mm × 600mm panel size to process a single die with 6-sided die protection (M-Series). Considerations for repassivation, redistribution layer and solder ball placement will be discussed. Challenges pertaining to large panel processing through the repassivation and redistribution layer will be presented, panel level inspection considerations post mold cure, reliability considerations and future of 600mm × 600mm panel level processing for 6-sided die protection will be summarized.