By Paula Doe, SEMI

Emerging opportunities for advanced packaging solutions for heterogeneous integration include a lot more than logic, memory and sensors. There’s also the challenges of packaging integrated photonics, flexible electronics, and high-voltage, high-temperature wide-bandgap power devices. Speakers from the National Network for Manufacturing Innovation Institutes targeting these new growth markets will update the SEMICON West 2016 audience on their efforts to cut the time and cost of moving from R&D to volume production for U.S. companies by supporting development of key technologies, U.S.-based facilities for fabrication and packaging, and education of the workforce.

Integrating silicon with optics

The new American Institute for Manufacturing Integrated Photonics (AIM Photonics) is ramping up its program to spur development of U.S. technology and manufacturing capability for integrated photonics, for next-generation high performance computing, telecommunications, and sensors. In the packaging space, first steps will be a university-industry effort to develop passive fiber-to-silicon assembly technology and automated test equipment, with a manufacturing facility targeted for 2017.

“We’re focusing on packaging, assembly and test since it accounts for most of the cost of integrated photonics,” says CEO Michael Liehr, who will update on the plans to facilitate U.S. manufacturing in this emerging sector in the Packaging Photonics session at SEMICON West on July 12.

Attaching an optical fiber of 120µm diameter to a waveguide of only several thousand angstroms remains a major challenge, typically requiring active alignment.  Volume production will need a passive alignment solution, which will require some combination of major improvement in precision of current placement tools (such as with image recognition) with some way to make the coupling more fault tolerant ─ such as by using an interposer to bridge the gap. Tool makers will need standard package interfaces to make common, not custom equipment. The institute will also work on the packaging issues of integrating the laser with the waveguides and other optical features on silicon.

“Key elements are also missing for test,” Liehr notes. “The in-line part is missing. No one has put together a commercially available system that includes the prober, the optical detection, and the coupler needed.”  The institute is putting together a university and industry team to develop solutions, and then will equip a facility to do the test, assembly and packaging of these photonic integrated circuits.

AIM Photonics also targets a Process Design Kit (PDK) design kit by the end of the year for its multi-project photonic wafers run in its front-end fab. Besides data center and telecommunications applications of integrated photonics, AIM Photonics is working with companies on phased arrays and optical sensors for healthcare and defense applications. The organization is a public-private venture, funded by the U.S. Department of Defense, the States of New York, Massachusetts, California, Arizona, and university and industry members.

Integrating silicon die into flexible, conformable electronics systems

Another emerging “packaging” opportunity is integrating silicon intelligence into  flexible, stretchable products. “People have been talking for decades now about a purely printed solution, but printed transistors do not have enough mobility for the needed performance, and in a switching application will burn out in about a day” notes Jason Marsh, Director of Technology at NextFlex, the Manufacturing Innovation Institute for Flexible, Hybrid Electronics, who will talk about this effort at the SEMICON program on flexible packaging July 14. “But there is real demand for flexible, conformable products for medical wearable and implantable devices and for IoT edge devices.”  The collaborative program aims to develop the manufacturing technology to enable these products, by integrating silicon die into flexible, stretchable environments.

This will require the development of new processes for bridging directly from ~100µm-scale printed electronic circuits to 50µm-scale PCB artwork to much finer die-level bond-pad pitch, eliminating the usual intervening steps ─ of wirebond/flip chip, package, interposer, circuit board, connector ─ all at low temperature and with good signal integrity. Potential approaches could include flip chip with an anisotropic conductor connection, or alternatively, printing the traces directly on bigger pond pads. The institute aims to develop the basic building blocks of the technology and put together a U.S. supply chain that companies can then use to develop and manufacture their own products. NextFlex is building a facility in San Jose for the technology, which members can use to develop prototypes and build their pilot products.

Building this new manufacturing supply chain means re-thinking the traditional food chain of circuit board, packaging and assembly. “We may need to do things in different order, with die attach to the substrate before circuitization, and may need big arrays on big substrates, with new process tools to handle them,” suggests Marsh. “Package and assembly suppliers will need to understand more of the full end-to-end process, with assembly companies understanding packaging, and packaging companies understanding interposers.” The project aims to help bring these suppliers together, and also to help develop the necessary technical expertise in the workforce in the U.S. “The goal is to accelerate the speed of development from some 5-6 years to 1-2 years,” says Marsh.

The program is funded by $75 million from the U.S. government, and $96 million from the City of San Jose, and other corporate, academic, and government partners.

Building a U.S. ecosystem for wide bandgap power semiconductor manufacturing

PowerAmerica, the Next Generation Power Electronics Manufacturing Innovation Institute, aims to build the U.S. ecosystem for manufacturing wide bandgap power semiconductors, by supporting R&D, production facilities, and workforce development to accelerate the adoption of these smaller, lighter and more energy efficient power systems, and to make it easier for new and small U.S. companies to develop products.

“It’s about driving down cost and validating the reliability of SiC and GaN for demanding power electronics applications. The physics are clear. Wide bandgap semiconductors can offer very high-power densities and higher performance with a lower cost bill of materials. We are rapidly approaching the tipping point where market demand and production volume will bring the price of wide bandgap devices down to match silicon in $/Amp,” says John Muth, PowerAmerica’s deputy director, who will update on the effort in the power packaging program at SEMICON West on July 12.

Taking full advantage of the physical properties of wide bandgap semiconductors for high performance will require highly optimized packages that can handle high voltages while minimizing inductance and efficiently remove heat, with more reliable materials for interconnections, die attach, and baseplate/substrates, and better cooling solutions. One result of the packaging projects to date are the low inductance, high performance power modules recently announced by Wolfspeed.

PowerAmerica activities across the supply chain range from the 6-inch SiC foundry at X-Fab in Lubbock, Texas, now being used by five members, to products under development by end users across in transportation, renewable energy, motor drives, data centers, and the power grid, at members such as ABB, Agile Switch, Atom Power, John Deere, Navitas, Lockheed-Martin, and Toshiba.

The institute has recently also started to invite unsolicited proposals that solve a technical problem to help grow and strengthen the supply chain or to accelerate adoption of SiC or GaN into new products. All projects have 1:1 cost sharing, and require a clear path to market. Other efforts include aggressive demonstrations of wide bandgap semiconductor performance by universities, industry-led road mapping activities, and curriculum development at member universities, and tutorials and short courses to bring industry engineers quickly up to speed in GaN and SiC technology.

The five-year $146 million program is funded by $70 million from DOE and another $76 million from cost matching from its members and the state of North Carolina.

To learn more about SEMICON West 2016, visit the Schedule-at-a-Glance and learn about the eight forums.

Correction: The first draft of this article stated in error that Jason Marsh’s talk would take place on July 12. Jason Marsh will speak on flexible packaging at SEMICON West on July 14.