Manufacturing Bits: Feb. 9

3D chip consortium
The 3D integration consortium of IRT Nanoelec has a new member–EV Group.

Based in Grenoble, France, IRT Nanoelec is an R&D center headed by CEA-Leti. Formed in 2012, the 3D integration consortium is one of IRT’s core programs.

EV Group joins Leti, Mentor Graphics, SET and STMicroelectronics as members of the 3D consortium. The program is developing a 3D integration lab that addresses the entire manufacturing flow in the 3D chip arena. It hopes to make it easier for the industry to develop 3D chips.

EV Group will help propel the development of advanced 3D wafer-to-wafer bonding technologies. With EV Group, the consortium expects to achieve an interconnection pitch of about 1µm, according to Séverine Chéramy, director of the 3D integration program of IRT Nanoelec.

“The work with EVG, in the frame of IRT Nanoelec, will undoubtedly add value to the current program, because wafer-to-wafer stacking using direct Cu-to-Cu bonding is key for advanced 3D technologies, specifically for imaging application and 3D partitioning,” she said.

Warm dense matter
The Department of Energy’s SLAC National Accelerator Laboratory has made a major discovery. Researchers assumed that tiny objects would blow up when hit by SLAC’s X-ray laser. Instead of blowing up, the nanoparticles initially shrank.

The findings could provide an understanding into the world of nanomaterials and warm dense matter. Warm dense matter, a state of matter between a solid and a plasma, is believed to be at the cores of giant gas planets in our solar system and exoplanets.

The experiments took place at SLAC’s Linac Coherent Light Source (LCLS) X-ray laser. Researchers exposed tiny clusters of xenon atoms to two consecutive X-ray pulses. The clusters were heated by the first pulse for 10 femtoseconds. The second pulse then probed the clusters’ atomic structures over the next 80 femtoseconds.

Experimental setup used to determine that nanometer-sized particles first shrink before exploding after being hit with very intense X-rays. (Source: SLAC)

“The unique nature of the LCLS X-ray pulse allowed us to create a freeze-frame movie of the response, with a resolution of about a tenth of the width of a single xenon atom,” said LCLS and Stanford University graduate student Ken Ferguson, on SLAC’s Web site.

“This phenomenon had never been observed before, nor had it been predicted by any of the existing theories,” he said. “We expect it to have implications for many ultrafast X-ray laser experiments, especially those geared toward single-particle imaging with very intense X-ray pulses.”

Copper atom lasers
Riken has developed the world’s first atomic X-ray laser capable of generating high-energy X-rays with an ultrashort wavelength of 1.5 angströms or 0.15nm.

This wavelength is similar to the diameter of a copper atom. It is almost ten times shorter than the wavelengths of X-rays produced by earlier atomic lasers.

To accomplish the so-called copper atomic laser, Riken used its SACLA X-ray free-electron laser (XFEL) facility. Researchers then shined short pulses of intense x-rays from the SACLA onto a copper foil.

Amplified spontaneous emission was enhanced by combining the excitation pump pulse with a seed pulse. This was accomplished from the same XFEL excitation source operating in a two-color mode. With this approach, Riken achieved an unprecedented power density of about 10(19) watts per square centimeter.

An experimental setup used to achieve a copper atomic x-ray laser. (Source: Riken)

Until now, this amplification had been impossible to achieve in the lab. “We needed an extremely intense X-ray beam to create the highly excited states of copper atoms,” said Makina Yabashi, a researcher from Riken, on the organization’s Web site.

“The SACLA X-ray source has the highest intensity in the world, which we combined with state-of-the-art X-ray optics technology to focus the XFEL beam to a spot just 100 nanometers in diameter,” Yabashi said. “We expect this technology may be applied, for example, to explore quantum interference on a zeptosecond [10−21 second] scale.”