How scientists are accelerating next-gen microelectronics
Multi-institutional team led by Berkeley Lab could help chip manufacturers race ahead of Moore’s Law
BY THERESA DUQUE, SCIENCE WRITER, BERKELEY LAB.
A NEW CENTER led by Lawrence Berkeley National Laboratory (Berkeley Lab) could accelerate the next revolution in microchips, the tiny silicon components used in everything from smartphones to smart speakers, life-saving medical devices, and electric cars.
The new center, called CHiPPS – or the Center for High Precision Patterning Science – is led by Berkeley Lab microelectronics expert Ricardo Ruiz. He is also a staff scientist in Berkeley Lab’s nanoscience user facility, the Molecular Foundry.
“Advanced computer chips are essential to modern life. Staying at the forefront of this technology – and keeping pace with Moore’s Law – is critical to our economic security and national defense,” Ruiz said.
Over the course of four years, Ruiz and his research partners will direct their diverse scientific expertise toward a common goal: Gaining new insight into the science of extreme ultraviolet lithography or EUVL, a revolutionary technique that enables the world’s leading semiconducting manufacturers to pack more than 100 billion transistors – the tiny components that help a computer retain and process data – into a chip the size of a fingernail.
The team includes Berkeley Lab scientists from the Molecular Foundry, the Advanced Light Source, the Center for X-Ray Optics, the Chemical Sciences Division, and the Energy Storage & Distributed Resources Division, along with collaborators from Argonne National Laboratory, San José State University, Stanford University, the University of California at Santa Barbara, and Cornell University.
The researchers’ work could help chip manufacturers make even smaller, more powerful chips, and support the goals of the Creating Helpful Incentives to Produce Semiconductors and Science Act, which aims to mitigate supply chain disruptions by helping the U.S. design and produce the world’s most advanced chips domestically. (The CHIPS and Science Act was signed into law by President Joe Biden last summer.)
Last year, the U.S. Department of Energy awarded the CHiPPS research center a total of $11.5 million over four years through the Energy Frontier Research Centers program to pursue fundamental research in EUV lithography, including new materials and their interaction with EUV light. The CHiPPS center’s efforts comprise four research “thrusts” focused on photomaterials synthesis, new “hierarchical” self-assembling materials, theory and modeling, and new techniques to characterize EUV lithography materials with atomic precision.
The CHiPPS research center not only aims to advance EUVL research, but it also places great emphasis on workforce development to nurture the next generation of scientists and engineers, Ruiz said. Through a collaboration with San José State University, the CHiPPS center offers an immersive work training program to four students every summer, consisting of two undergraduate students and two master’s students. (The inaugural cohort commenced in June.)
Before joining Berkeley Lab in 2019, Ruiz worked as a research scientist in the microelectronics and data storage industry, specializing in polymer-based lithography techniques for magnetic data storage at Hitachi Global Storage Technologies, and alternative nanofabrication techniques for non-volatile memories at Western Digital. He earned his Ph.D. in physics from Vanderbilt University in 2003, and worked as a postdoctoral researcher at Cornell and IBM before joining Hitachi Global Storage Technologies in 2006.
He shares his perspective in this Q&A.
Q. How will the new CHiPPS Energy Frontier Research Center advance microelectronics?
Ricardo Ruiz: The mission of the CHiPPS center is to create new fundamental understanding and control of patterning materials and processes with atomic precision. The goal is to enable the large-scale manufacturing of next-generation microelectronics.
To unpack that a little bit, that means that our focus lies in the scientific exploration of an advanced method known as extreme ultraviolet (EUV) lithography.
EUV lithography is key to creating integrated-circuit patterns on the scale of a billionth of a meter in the materials that are used to manufacture advanced microchips. It’s the latest advance in lithography, a technique that uses light to print tiny patterns in silicon to mass produce microchips.
Over the past five decades, lithographic techniques have progressively evolved from the use of light in the visible range, where wavelengths are as small as 400 nanometers, to the latest advance: the extreme ultraviolet range with short wavelengths of 13.5 nanometers, about 40 times smaller than the wavelengths of visible light. Such advances in lithography have enabled the use of smaller and smaller wavelengths to fabricate smaller, denser microchips.
EUV lithography was just recently introduced in the production of microchips in 2019, and it still faces multiple challenges, particularly in the development of advanced patterning materials suitable for high-resolution and high-throughput manufacturing processes using light in the form of EUV radiation.
The light-sensitive chemical films called photoresists or “resists” in use today for microchip production do not efficiently absorb EUV radiation, and little is known about how these photoresists interact with EUV light.
And that’s where we come in.
At CHiPPS, we are taking this opportunity to design new photoresist materials specifically designed to work with EUV radiation. We aim to tackle fundamental scientific challenges to better understand and control the chemical reactions arising from the interaction between EUV radiation and resist materials. These tiny, but localized, chemical changes inside the resist is what enables the fabrication of smaller patterns to print, for example, smaller transistors, facilitating the production of faster and denser microchips.