Manufacturing Bits: Sept. 1

Free-electron laser EUV consortium
Extreme ultraviolet (EUV) lithography is delayed. Chipmakers hope to insert EUV at the 7nm node, but that’s not a given. As before, the big problem is the EUV light source. So far, the source can’t generate enough power to enable the required throughput for EUV in high-volume production.

ASML’s current EUV source is operating at 80 Watts, up from 10 Watts a year ago. Chipmakers, however, want 250 Watts of power to put EUV into mass production.

Today, there are various efforts to solve the problem. For example, ASML and Gigaphoton are separately working on higher power EUV sources.

And then, there are new and different approaches. For example, an industry consortium was quietly formed two years ago to develop a next-generation, free-electron laser (FEL) technology specifically for EUV. The FEL EUV consortium includes SLAC, LBNL, Fermilab, Argonne, Cornell, UCLA, RadiaBeam, AES and RadiaSoft.

Starting this year, the FEL EUV consortium has stepped up its activities. And the group revealed more details about its plans at the 2015 EUVL Workshop in June.

Traditionally, each EUV tool requires an EUV power source. In contrast, using X-ray technology, the FEL concept makes use of a linear accelerator to generate a high-current electron beam. In theory, a single FEL could produce kilowatt levels of power. All told, the single FEL could generate enough power for multiple EUV tools within the same facility.

For the FEL EUV consortium, the group is looking at utilizing SLAC’s next-generation FEL X-ray source, dubbed the LCLS-II. This is an upgrade of SLAC’s current Linac Coherent Light Source (LCLS). Funded by the U.S. Department of Energy (DOE) several years ago, the LCLS was the world’s first X-ray free-electron laser (XFEL).

The LCLS-II is being developed as part of an effort by the U.S. DOE, but the completion date is still unclear. “The schedule for LCLS-II will not be finalized until the Department of Energy’s Critical Decision (CD)-2 and CD-3 reviews, which are expected to happen sometime next year,” according to a spokesman for the SLAC National Accelerator Laboratory.

The FEL EUV consortium will utilize the LCLS-II, but this is a separate and independent activity. In any case, there are two basic types of EUV FEL topologies–straight shooter FEL and energy recovery linac (ERL) FEL. “Our consortium is taking a comparative look at a straight shooter FEL,” said Aaron Tremaine, a senior scientist at the SLAC National Accelerator Laboratory. “The goal of the consortium is to apply current state-of-the-art superconducting FEL technology, and apply this to EUV lithography to deliver 13.5nm radiation required for lithography.”

The FEL EUV consortium is looking to develop a 10-kW straight shooter topology. Each member of the consortium is developing pieces of the linear system, which consists of the following components—a high-repetition-rate photoinjector; a CW superconducting linac; a permanent magnet undulator; and a high power beam dump.

The group hopes to develop all major technical accelerator systems for an EUV FEL by 2017, according to the consortium members.

3D-printed fish
The University of California at San Diego has developed a 3D printing technology to make fish-shaped microrobots.

The 3D-printed fish, dubbed microfish, could take on several different fish-like shapes, such as sharks and manta rays. The 3D-printed fish can swim in liquids. They are chemically powered by hydrogen peroxide and are magnetically controlled. They can be used in biotech applications, such as detoxification, sensing and directed drug delivery.

3D-printed microfish contain functional nanoparticles that enable them to be self-propelled. (Image credit: J. Warner, UC San Diego)

Researchers have developed a 3D printing technology called microscale continuous optical printing (μCOP). With the technology, researchers can print an array containing hundreds of microfish. The fish could measure 120 microns long and 30 microns thick.

The μCOP technology makes use of a digital micromirror array device (DMD) chip. The MEMS-like device contains about 2 million micromirrors. Each micromirror is individually controlled to project UV light in a pattern. Using photosensitive material, the microfish are built one layer at a time.

“We have developed an entirely new method to engineer nature-inspired microscopic swimmers that have complex geometric structures and are smaller than the width of a human hair. With this method, we can easily integrate different functions inside these tiny robotic swimmers for a broad spectrum of applications,” said Wei Zhu, a Ph.D. student at the Jacobs School of Engineering at UC San Diego, on the university’s Web site.

LEGO AFMs
In 2003, students built atomic force microscopes (AFMs) or nanoscopes using toy LEGOs. The AFMs cost less than $500 to make.

The same group that sponsored the first effort is starting a new project. The new project, dubbed LEGO2NANO, involve students from the University College London (UCL), as well as students from Beijing, Boston and Taiwan. They are meeting at Tsinghua University’s Beijing and Shenzhen campuses.

LEGO2NANO will develop low-cost scientific instruments such as the Open AFM. This is an open-source AFM assembled from cheap, off-the-shelf electronic components, such as Arduino, LEGO and 3D printable parts.