COO interview: SkyWater’s Sakamoto on turning up the volume

Interviews | September 30, 2024

By Peter Clarke

Advanced Packaging foundry

John Sakamoto is president and COO of SkyWater Technology Inc. (Bloomington, Minnesota). Having been in post for one year he says he plans to increase the volume output of the foundry and of complementary operations in packaging.

SkyWater is an engineering services and volume manufacturing foundry formed in 2017 by the buy-out of Cypress Foundry Solutions, previously a subsidiary of Cypress Semiconductor Corp., which itself was acquired by Infineon Technology AG.

Sakamoto, who reports to CEO Thomas Sonderman, came to SkyWater having amassed 25 years of experience in various executive positions with Altera, Intel, and Marvell.

To date SkyWater has offered a broad range of services, including helping integrated device manufacturers (IDMs) and others develop chips and specialized manufacturing processes for applications in the aerospace, defense, automotive, consumer, healthcare, and industrial sectors. SkyWater is also a ‘Trusted Supplier’ to the US Department of Defense.

Engineering revenue

SkyWater offers, mixed-signal CMOS, rad-hard, superconducting, photonic circuits, MEMS and so-called heterogenous integration, which covers various forms of multi-die assembly.

“The majority of our revenue is ATS [advanced technology services]; about 90 percent compared to 10 percent wafers. Wafer revenues have been down partly because the industrial market has been soft but we think 2024 is a low point,” said Sakamoto.

In 2Q24 ATS revenues were US$61.7 million up compared with US52.1 million in the same quarter a year before. However, wafer services were US$5.8 million, down from US$16.8 million a year before. As well as market softness SkyWater has had to face the taper down of products that were being made for Cypress and then Infineon on legacy contracts.

Sakamoto states that the provision of ATS and SkyWater’s actions as an R&D fab are about to pay off in terms of volume manufacturing. “As an R&D fab we are in a position to move customers into high volume.” He added: “We have a medical circuit and thermal imaging going into products.”

SkyWater has also made good business out of installing semiconductor manufacturing tools and passing ownership of those tools on to its ATS customers. For 2Q24 SkyWater reported US25.9 million in revenue resulting from the sale of equipment to customers.

E-beam lithography

One of the latest pieces of tooling to arrive at the Bloomington wafer fab is a multi-column e-beam lithography platform from Multibeam Corp. (Santa Clara, Calif.) for the mask-less definition of leading-edge semiconductors.

Multibeam claims its MB Platform has 10x better resolution than optical laser and to have a 100x advantage over optical lithography in terms of depth of focus and field of view.

Conventionally e-beam lithography has had a major weakness. That writing a resist with a single directed beam of electrons is slow when it has to define thousands or millions of transistors. One way to speed this process up is to create thousands of controllable electron-beams from a primary source.

Multibeam’s systems don’t operate on thousands of beams but multiple electron columns are designed to cover a specific portion of a given substrate. This increases efficiency compared to a single-beam but also allows systems to scale and cover a range of substrate sizes 200mm, 300mm, and beyond, without compromising throughput and productivity.

“As far as the process nodes SkyWater is aiming for with the Multibeam tool… it’s 90nm and 130nm, but we’re working on many potential applications from sub-65nm to 2micron,” said Sakamoto.

SkyWater is not engaged at the leading-edge in silicon so it is expected that the unit will be used for photonics, rapid prototyping, and other specialist applications, including advanced packaging. And that fits in with one of Sakamoto’s other priorities; to accelerate SkyWater’s move into advanced packaging, something that is not readily available in North America.

It’s time to package

In January 2021 SkyWater took over a facility in Osceola County, Florida, as the foundation for an advanced packaging technology services business. Three years later SkyWater announced that it had won a five-year contract from the DoD worth US$120 million to fund the facilitization, tooling and build-out of the Center for Neovation in Osceola County.

As part of the project SkyWater will be the first US provider of Deca Technologies’ fan-out wafer level packaging (FOWLP) capabilities for both government and commercial customers. The aim is to process both 200mm and 300mm device wafer formats. The award includes options for an additional $70 million, for a total value of up to $190 million.

Again, this is something on the verge of happening. “Right now I would say 99 percent of our revenue is in Bloomington and 1 percent in Florida,” said Sakamoto. “But that is about to change in 2025. It is a very large cleanroom that, when facilitized, will support development and volume production.

Sakamoto offers up the example of fabless chip company AMD which might like to turn to TSMC in Arizona to get its ICs made but then must ship wafers to South-east Asia for packaging, more or less nullifying any benefit of domestic chip production.

And as for TSMC’s most advanced packaging – the so-called CoWoS [Chip-on-Wafer-on-Substrate]: “TSMC has said it won’t put packaging in the US,” said Sakamoto. “And TSMC won’t package multi-sourced die. There is push-back on that with the exception of memory die which they will accept,” he added. “We want to be more versatile and we think top-tier companies will come to us as an alternative source.”

Sakamoto characterizes much of the chiplet-style advanced packaging as “chip last.” He said there is also “chip first” assembly where passive and active components are buried in a substrate creating a “system on a substrate”.

“Imagine processor, memory, sensors, analog, MCU all in the substrate.” This could be for soldiers’ radios where weight benefits are important. It also has anti-tamper benefits. “We will support both types of packaging,” said Sakamoto.

To pursue that aim SkyWater has just appointed Bassel Haddad as senior vice president and general manager of advanced packaging. Haddad was previously with Intel from 2011 where he managed edge device and AI products.

Haddad reports to Sakamoto and will be responsible for all aspects of the advanced packaging business and building a strong commercial manufacturing presence.

“This is a massive opportunity. Forecasts put the global annual market for advanced packaging at US$15 billion with 20 percent of that in the US,” said Sakamoto.