New Process Creates 3-D Nanostructures with Magnetic Materials

June 25, 2008
New Process Creates 3-D Nanostructures with Magnetic Materials
Working in the trenches: Transmission electron microscopy image of a thin cross section of 160 nanometer trenches shows deposited nickel completely filling the features without voids. (Color added for clarity.) Credit: NIST

Materials scientists at the National Institute of Standards and Technology (NIST) have developed a process to build complex, three-dimensional nanoscale structures of magnetic materials such as nickel or nickel-iron alloys using techniques compatible with standard semiconductor manufacturing. The process could enable whole new classes of sensors and microelectromechanical (MEMS) devices.

The NIST team also demonstrated that key process variables are linked to relatively quick and inexpensive electrochemical measurements, pointing the way to a fast and efficient way to optimize the process for new materials.

The NIST process is a variation of a technique called “Damascene metallization” that often is used to create complicated three-dimensional copper interconnections, the “wiring” that links circuit elements across multiple layers in advanced, large-scale integrated circuits. Named after the ancient art of creating designs with metal-in-metal inlays, the process involves etching complex patterns of horizontal trenches and vertical “vias” in the surface of the wafer and then uses an electroplating process to fill them with copper. The high aspect ratio features may range from tens of nanometers to hundreds of microns in width. Once filled, the surface of the disk is ground and polished down to remove the excess copper, leaving behind the trench and via pattern.

The big trick in Damascene metallization is ensuring that the deposited metal completely fills in the deep, narrow trenches without leaving voids. This can be done by adding a chemical to the electrodeposition solution to prevent the metal from building up too quickly on the sides of the trenches and by careful control of the deposition process, but both the chemistry and the process variables turn out to be significantly different for active ferromagnetic materials than for passive materials like copper. In addition to devising a working combination of electrolytes and additives to do Damascene metallization with nickel and a nickel-iron alloy, the NIST team demonstrated straightforward measurements for identifying and optimizing the feature-filling process thereby providing an efficient path for the creation of quality nanoscale ferromagnet structures.

The new process makes it feasible to create complex three-dimensional MEMS devices such as inductors and actuators that combine magnetic alloys with non-magnetic metallizations such as copper interconnects using existing production systems.

Source: NIST

Explore further: Huge grains of copper promote better graphene growth

Related Stories

Huge grains of copper promote better graphene growth

December 6, 2013

To technology insiders, graphene is a certified big deal. The one-atom thick carbon-based material elicits rhapsodic descriptions as the strongest, thinnest material known. It also is light, flexible, and able to conduct ...

NIST 'Standard Bullet' fights gang violence

January 19, 2007

Researchers at the National Institute of Standards and Technology (NIST) have developed a copper bullet designed to help end criminal sprees without once being fired. Crime laboratories can use NIST's "Standard Bullet" to ...

Chemists measure copper levels in zinc oxide nanowires

February 19, 2008

Chemists at the National Institute of Standards and Technology have been the first to measure significant amounts of copper incorporated into zinc oxide (ZnO) nanowires during fabrication. The issue is important because copper ...

Recommended for you

Physicists develop new technique to fathom 'smart' materials

November 26, 2015

Physicists from the FOM Foundation and Leiden University have found a way to better understand the properties of manmade 'smart' materials. Their method reveals how stacked layers in such a material work together to bring ...

Mathematicians identify limits to heat flow at the nanoscale

November 24, 2015

How much heat can two bodies exchange without touching? For over a century, scientists have been able to answer this question for virtually any pair of objects in the macroscopic world, from the rate at which a campfire can ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.