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systems; as such, these lithography tools next generation of extremely large field In the past, the semiconductor industry
are also being used for RDL patterning steppers arrive with higher NA to support referenced the International Technology
involving AICS CCL. Of course, LDI has less than 2/2µm l/s. Roadmap for Semiconductors (ITRS) to
the advantage of not requiring reticles, but At this time, R&D programs using align original equipment manufacturers
it is limited in resolution and throughput CCL and/or glass substrates are racing (OEMs) with material and substrate
and not suitable for high-volume toward the 2/2µm l/s node. HVM is still at suppliers to deliver solutions with a clear
manufacturing (HVM). LDI is more of a 9/12µm l/s and is moving slowly towards indication of timing. Unfortunately, the
research and development (R&D) tool to 5/5µm l/s, with lithography requirements Heterogeneous Integration Roadmap
test out new designs and prototype larger easily satisfied by the extremely large (HIR) does not have the level of detail
geometry packages. field size steppers. The HVM of glass required for lithography.
For AICS CCL processes, HVM substrates and 2/2µm l/s are not expected In the absence of a detailed industry-
steppers have low NA, which provide to occur until the end of the decade, so d e f i n e d l i t ho g r a ph y r o a d m a p ,
a large DOF; this allows steppers to there is still time to gain a comprehensive collaboration between OEMs and the
easily accommodate the non-flatness understanding of the lithography material/substrate supply chain will
of the substrate material. Currently, the requirements for 2/2µm l/s. Still, there be imperative. To help meet these
RDL l/s resolution for extremely large are many lithography questions that challenges, Onto In novation has
field size HVM steppers is limited to need to be answered. For instance, what established the Packaging Application
3µm. However, as we move closer to is the correct NA and DOF requirement Center of Excellence ( PACE) i n
RDL of 2/2µm l/s, stepper solutions and field size? Of course, customers are ou r Wilming ton, Massachuset ts,
are available, albeit with smaller field looking for these performance parameters headquarters to address this issue.
sizes. The downside here is that such to go beyond the laws of physics, so Collaborators are already engaged with
solutions limit package sizes to less than there needs to be more discussions and the company in defining projects to
60mm x 60mm—smaller than what most collaboration to determine what will help answer many of the most pressing
advanced packages will need—until the be required. lithography questions.
PACE will provide access to next-
generation ext remely large-f ield
steppers, inspection, metrology and
software capabilities that are currently
in development. Furthermore, OEMs
and supply chain partners will be able to
develop next-generation materials using
the center’s infrastructure and its team’s
advanced packaging knowledge to provide
customers with the solutions they need
to accelerate their technology roadmaps,
whether the future is in CCL or glass.
This collaborative opportunity posed
by PACE may help determine the answer
to the bigger question of which technology
will win the race: copper clad laminate or
glass. Until then, the debate continues.

Biography
Doug Brown is Senior Director of
Product Management, Lithography, at
Onto Innovation, Wilmington, MA. He is a
graduate of the U. of Arizona, with a PhD
in Electrical Engineering and a Master’s
in Electrical Engineering and another
Master’s in Physics. For the past 25 years,
his focus has been on capital equipment
development for the semiconductor
industry, with tool introductions spanning
plasma etch, deposition, ion implantation,
liquid metrology and lithography. Email
Doug.Brown@ontoinnovation.com

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