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600mm wafer-level fan-out on panel-level processing

with 6-sided die protection

By Jacinta Aman Lim, YunMook Park, Byung Cheol Kim, Edil Devera [nepes]
C urrently, a 300mm carrier This paper will present a case study 6.25mm fan-out package, was tested with

wafer for fan-out wafer-
level packaging (FOWLP) of utilizing 600mm x 600mm panel board-level temperature cycling (TC) on
a 1mm board, with SAC405. The bump
size to process a single die with 6-sided
is the mainstream format used for power die protection. Considerations for pitch was at 500µm with no under bump
management integrated circuits (PMICs), repassivation, redistribution layer and metallization (UBM). There were no TC
radio frequency (RF) and other single- solder ball placement will be discussed. failures up to 1000 cycles. The plot in
die applications. As the volume of these Challenges pertaining to large panel Figure 1 shows >200% improvement for
devices continues to rise, the need for processing through the repassivation and TC over WLCSP [1].
migration to panel sizes larger than 300mm redistribution layer will be presented;
becomes a necessity for cost reduction and additionally, panel-level inspection Fan-out packaging drivers
capacity. considerations post mold cure, reliability As can be seen from Figure 2, some
The fastest adoption of fan-out considerations, and the future of 600mm x of the major market drivers are RF, audio
technology is now in 5G, automotive and 600mm panel-level processing for 6-sided codec, PMIC, radar, 5G and high-speed
healthcare. Traditional applications such die protection will be summarized. computing [2].
as audio codecs, PMICs, micro-controller 5G adoption is central to large data
units (MCU) and RF continue to use Introduction to wafer-level transfers to enable a new user experience,
FOWLP as an alternative to wafer-level packaging and enabling better cloud-based business
chip-scale packaging (WLCSP) due to its There are several types of wafer- management as well as increasing our
5-sided or 6-sided die protection. As fan- level packaging (WLP) in the industry. level of interaction with one another. In
out packaging becomes mainstream and The mainstream is WLCSP, or fan-in, comparison to flip-chip ball grid array
in order to get broader adoption of it, the followed by variations of FOWLP. In the (FCBGA) packages, the interconnect
need for driving down the cost continues example shown in Table 1, we look at length between the integrated circuit
to be at the forefront of fan-out suppliers. two fan-out processes in comparison with (IC) and the antenna is shorter, thereby
The 600mm x 600mm format utilized WLCSP. In comparison with processing reducing the signal loss from the radio
in this study leverages existing backend complexity, the left-most column frequency (RF) chip in fan-out packaging.
processing equipment used on 200mm and (M-Series™) ranks highest, with WLCSP Leading players such as TSMC and
300mm wafers for cost savings. Utilizing being the least complex. In terms of Mediatek have shown that fan-out
existing equipment enabled the panel to package reliability, 6-sided die protection packaging can enable low transmission
be singulated into 4x300mm or 9x200mm ranks highest compared to WLCSP as loss and high antenna performance for
square segments to enable probe testing. shown in the Weibull plot (Figure 1). mmWave system integration [2].
Coupling the 6-sided die protection In the plot, a 6mm x 6mm WLCSP test As for high-performance computing
process M-Series™ with 600mm x 600mm chip, which was also used on a 6.25mm x (HPC), a surge in the number of Internet
panel-level processing paves the way for
innovative methods for fan-out processing.
New photolithography processing that
utilizes 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
4x300mm, 9x200mm or 1x600mm for
the 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.
Table 1: Attributes between FOWLP and WLCSP.

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