Manufacturing Bits: Jan. 19

Bubble-pen lithography
The University of Texas at Austin has developed a new nano-patterning technology–bubble-pen lithography.

Researchers have devised a bubble-pen that enables optically-controlled microbubbles. The bubbles are used to pattern structures onto a surface at tiny dimensions. Bubble-pen lithography could be used in microelectronics, nanophotonics, and nanomedicine.

In simple terms, the pen makes use of a laser beam. The beam is focused underneath a sheet of gold nano-islands. This, in turn, generates a hotspot, thereby creating a microbubble out of vaporized water.The laser beam can also move around the microbubbles. In doing so, researchers can devise patterns and assemblies with different resolutions and architectures.

Bubble-pen lithography patterns tiny structures on a surface (Source: University of Texas)

In the lab, researchers used the technology to pattern quantum dots based on cadmium selenide and zinc sulphide (CdSe/ZnS). The dots were patterned on plasmonic substrates and polystyrene microparticles on two-dimensional materials.

“The ability to control a single nanoparticle and fix it to a substrate without damaging it could open up great opportunities for the creation of new materials and devices,” said Yuebing Zheng, an assistant professor at the University of Texas at Austin, on the university’s Web site. “The capability of arranging the particles will help to advance a class of new materials, known as metamaterials, with properties and functions that do not exist in current natural materials.”

Russian nano-engraving
The Moscow Institute of Physics and Technology (MIPT) and others have developed a nano-engraving technology.

Researchers have devised a laser deposition technique to enable patterns on glass at less than 100nm. Nano-engraving can be used to pattern circuits in microfluidics and other structures.

For some time, femtosecond lasers have been used to pattern structures on a surface. But the problem is that the resolution of the laser is limited. So instead, researchers use a so-called near-field effect. This involves using metal nanoparticles or a layer of dielectric microspheres on the lens in order to boost the resolutions. This technology also has drawbacks.

MIPT took another approach. Researchers combined laser processing with optically trapped microspheres. In the lab, researchers took borosilicate glass. The glass surface was processed by single laser pulses at 780nm.
Then, researchers used selective etching. This, in turn, produced pits in the laser-affected zones (LAZs). Researchers demonstrated production of pits at 70nm.

Laser deposition can enable tiny patterns on glass (Source: MIPT)

“Creating thin grooves and channels can be used in chemistry and biology fields–in the production of microfluidics and at various nano-plants,” said Aleksander Shakhov, a post-graduate of the faculty of General and Applied Physics at MIPT.

3D consortium
SET, known as Smart Equipment Technology, announced its participation in the 3D integration consortium of IRT Nanoelec, which is headed by CEA-Leti.

SET joins Leti, STMicroelectronics and Mentor Graphics to develop advanced 3D die-to-wafer stacking technologies, using direct copper-to-copper bonding. SET is a supplier in high-accuracy, die-to-die and die-to-wafer bonders.

Based in Grenoble, France, IRT Nanoelec is an R&D center. 3D integration is one of its core programs. The 3D integration program was launched in 2012. Séverine Chéramy, director of IRT Nanoelec’s 3D integration program, said the objective is to offer designers 3D die-to-wafer stacking at an aggressive pitch – less than 10µm – at high speed, at room temperature and without pressure or underfill.