Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New sensor bares faults in smallest possible, most advanced circuits

12.05.2003


A new scanning microscope developed at Brown University can uncover defects in the smallest and most complex integrated circuits at a resolution 1,000 times greater than current technology. The scanner removes a barrier to further shrinking of integrated circuits: As circuits get smaller, non-visual defects become harder to find.


Micro mouse bite
A current-density image, taken with a Circuit Scan 1000 high-resolution magnetic microscope, reveals a tiny flaw in one of two 0.25-micron metal wires in an integrated circuit chip. Further magnification (detail) shows the right-hand wire has a “mouse bite” along one of its edges, where the electrical current shows up as a tiny hot spot



“This microscope will allow manufacturers to find defects in each embedded wire in ever-tinier circuits,” said Brown University professor Gang Xiao. He developed the instrument’s hardware and software with Ben Schrag, who will receive his Ph.D. at Brown this month.

The microscope’s magnetic-scanning technology suggests a new small, non-invasive form of remote detection, said the researchers, who envision a “pass-over and detect” magnetic-sensor-tipped pen, for use in finding internal cracks within aircraft, sensing biological agents in the environment or body, or recognizing counterfeit bills or other objects.


Although magnetic sensing is used extensively, it is not applied widely for imaging electrical current flow, said Schrag. The only method that uses magnetic imaging to see current flow is restricted to extremely low temperatures, employing cryogenic aids such as liquid nitrogen. However, the Brown device works at room temperature. This design opens the way to greater use of magnetic sensing technology, he said.

“The factor of 1,000 improvement in spatial resolution is how much better we can do than this cryogenic technology,” Schrag said. “We are just scratching the surface of potential applications.”

Xiao and Schrag are using the technology to pinpoint how electrical current can form pinholes in state-of-the-art devices called magnetic tunnel junctions. These tiny sandwiches of ferromagnetic layers and insulating material are candidate memory storage cells to replace standard cells used in computer memory chips.

The researchers have “imaged” current flow in electrical components as small as 50 nanometers, the smallest commercially available components, half the size of conventional chips.

Until now, little or no technology existed for actually “watching” electrical current flow, said Schrag. Whenever current runs through wires, such as those embedded within the semiconducting material of an integrated circuit, it creates a magnetic field. By measuring spatial changes in that magnetic field, the microscope visualizes electrical current, even within wires buried under layers of advanced materials, he said.

“The device allows us to see the evolution of hot spots on each wire in a circuit and how each defect moves down the wire in the form of electrons moving atoms,” said Xiao. “To see a collection of atoms moving as a function of time is a capability that did not exist until now. We are witnessing the flow of electricity. It appears similar to an image of human blood flowing.”

The microscope is described in a paper in the May 12, 2003, issue of Applied Physics Letters. It features some of the same magnetic-scanning technology found in computer hard drives. A scanner does not touch what it reads. Instead, a magnetic sensor the size of a small pea moves quickly back and forth over a circuit through which current flows. The sensor collects information, which is then converted by algorithms into a color picture of electron flow. Color changes in the image reflect the intensity of electron flow as well as the presence of defects.

About the size of a refrigerator, the microscope is being reduced to the size of a desktop computer. “The new design will allow a technician to sit in front of a monitoring screen, as integrated circuits pass through a small open door, under a scanner and out the door,” Xiao said. Currently, the microscope takes a few minutes to scan a circuit. The researchers are working to reduce that time to as little as 30 seconds.

Xiao and Schrag have filed patents on several aspects of the technology, which has been transferred to Micro Magnetics, a Fall River, Mass., company that makes scanning devices for manufacturers of integrated circuits (computer chips). Images produced by the microscope may be viewed at http://www.micromagnetics.com/.

The National Science Foundation funded this work.

Scott Turner | Brown University
Further information:
http://www.brown.edu/Administration/News_Bureau/2002-03/02-125.html
http://www.micromagnetics.com/

More articles from Power and Electrical Engineering:

nachricht Researchers pave the way for ionotronic nanodevices
23.02.2017 | Aalto University

nachricht Microhotplates for a smart gas sensor
22.02.2017 | Toyohashi University of Technology

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>