Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Preventing Failure: New Magnetic Testing Technique Helps Ensure Reliability of Microelectronic Devices, PV Cells and MEMS Applications

Image shows an assembled magnetically actuated peel test (MAPT) specimen being prepared for analysis at the Georgia Institute of Technology. The silver cylinder in the center is the permanent magnet. (Image courtesy of Greg Ostrowicki and Suresh Sitaraman)
Image shows an assembled magnetically actuated peel test (MAPT) specimen being prepared for analysis at the Georgia Institute of Technology. The silver cylinder in the center is the permanent magnet.

(Image courtesy of Greg Ostrowicki and Suresh Sitaraman)

Abstract:
Taking advantage of the force generated by magnetic repulsion, researchers have developed a new technique for measuring the adhesion strength between thin films of materials used in microelectronic devices, photovoltaic cells and microelectromechanical systems (MEMS).

Preventing Failure: New Magnetic Testing Technique Helps Ensure Reliability of Microelectronic Devices, PV Cells and MEMS Applications

Atlanta, GA | Posted on April 15th, 2012

The fixtureless and noncontact technique, known as the magnetically actuated peel test (MAPT), could help ensure the long-term reliability of electronic devices, and assist designers in improving resistance to thermal and mechanical stresses.

"Devices are becoming smaller and smaller, and we are driving them to higher and higher performance," said Suresh Sitaraman, a professor in the George W. Woodruff School of Mechanical Engineering at the Georgia Institute of Technology. "This technique would help manufacturers know that their products will meet reliability requirements, and provide designers with the information they need to choose the right materials to meet future design specifications over the lifetimes of devices."

The research has been supported by the National Science Foundation, and was reported in the March 30, 2012 issue of the journal Thin Solid Films.

Modern microelectronic chips are fabricated from layers of different materials - insulators and conductors - applied on top of one another. Thermal stress can be created when heat generated during the operation of the devices causes the materials of adjacent layers to expand, which occurs at different rates in different materials. The stress can cause the layers to separate, a process known as delamination or de-bonding, which is a major cause of microelectronics failure.

"We need to find out if these layers will separate over time as they are used and subjected to thermal and other stresses," Sitaraman explained. "These systems are used in a wide range of applications from cell phones and computers to automobiles, aircraft and medical equipment. They must be reliable over the course of their expected lifetimes."

Sitaraman and doctoral student Gregory Ostrowicki have used their technique to measure the adhesion strength between layers of copper conductor and silicon dioxide insulator. They also plan to use it to study fatigue cycling failure, which occurs over time as the interface between layers is repeatedly placed under stress. The technique may also be used to study adhesion between layers in photovoltaic systems and in MEMS devices.

The Georgia Tech researchers first used standard microelectronic fabrication techniques to grow layers of thin films that they want to evaluate on a silicon wafer. At the center of each sample, they bonded a tiny permanent magnet made of nickel-plated neodymium (NdFeB), connected to three ribbons of thin-film copper grown atop silicon dioxide on a silicon wafer.

The sample was then placed into a test station that consists of an electromagnet below the sample and an optical profiler above it. Voltage supplied to the electromagnet was increased over time, creating a repulsive force between the like magnetic poles. Pulled upward by the repulsive force on the permanent magnet, the copper ribbons stretched until they finally delaminated.

With data from the optical profiler and knowledge of the magnetic field strength, the researchers can provide an accurate measure of the force required to delaminate the sample. The magnetic actuation has the advantage of providing easily controlled force consistently perpendicular to the silicon wafer.

Because many samples can be made at the same time on the same wafer, the technique can be used to generate a large volume of adhesion data in a timely fashion.

But device failure often occurs gradually over time as the layers are subjected to the stresses of repeated heating and cooling cycles. To study this fatigue failure, Sitaraman and Ostrowicki plan to cycle the electromagnet's voltage on and off.

"A lot of times, layers do not delaminate in one shot," Sitaraman said. "We can test the interface over hundreds or thousands of cycles to see how long it will take to delaminate and for that delamination damage to grow."

The test station is small enough to fit into an environmental chamber, allowing the researchers to evaluate the effects of high temperature and/or high humidity on the strength of the thin film adhesion. This is particularly useful for electronics intended for harsh conditions, such as automobile engine control systems or aircraft avionics, Sitaraman said.

"We can see how the adhesion strength changes or the interfacial fracture toughness varies with temperature and humidity for a wide range of materials," he explained.

So far, Sitaraman and Ostrowicki have studied thin film layers about one micron in thickness, but say their technique will work on layers that are of sub-micron thickness. Because their test layers are made using standard microelectronic fabrication techniques in Georgia Tech's clean rooms, Sitaraman believes they accurately represent the conditions of real devices.

"To get meaningful results, you need to have representative processes and representative materials and representative interfaces so that what is measured is what a real application would face," he said. "We mimic the processing conditions and techniques that are used in actual microelectronics fabrication."

As device sizes continue to decline, Sitaraman says the interfacial issues will grow more important.

"As we continue to scale down the transistor sizes in microelectronics, the layers will get thinner and thinner," he said. "Getting to the nitty-gritty detail of adhesion strength for these layers is where the challenge is. This technique opens up new avenues."

Writer: John Toon

####

For more information, please click here

Contacts:
Research News & Publications Office
Georgia Institute of Technology
75 Fifth Street, N.W., Suite 314
Atlanta, Georgia 30308 USA

Media Relations Contacts:
John Toon
404-894-6986


Abby Robinson
404-894-6986

Copyright © Georgia Tech

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Information storage with a nanoscale twist: Discovery of a novel rotational force inside magnetic vortices makes it easier to design ultrahigh capacity disk drives March 28th, 2017

ATTOPSEMI Technology Joins FDXcelerator Program to Deliver Advanced Non-Volatile Memory IP to GLOBALFOUNDRIES 22 FDX Technology Platform: Leading-edge I-fuse brings higher reliability, smaller cell size and ease of programmability for consumer, automotive, and IoT applications March 27th, 2017

Leti and HORIBA Scientific to Host Webinar on Ultrafast Characterization Tool: Plasma Profiling Time-of-Flight Mass Spectrometer Tool Cuts Optimization Time In Layer Deposition and Fabrication of Wide Range of Applications March 27th, 2017

Laser activated gold pyramids could deliver drugs, DNA into cells without harm: Microstructures create temporary pores in cells March 27th, 2017

Thin films

Dual-function nanorod LEDs could make multifunctional displays February 11th, 2017

NREL research pinpoints promise of polycrystalline perovskites February 8th, 2017

New material with ferroelectricity and ferromagnetism may lead to better computer memory December 21st, 2016

ANU invention to inspire new night-vision specs December 7th, 2016

MEMS

Smart multi-layered magnetic material acts as an electric switch: New study reveals characteristic of islands of magnetic metals between vacuum gaps, displaying tunnelling electric current March 1st, 2017

Engineers shrink microscope to dime-sized device February 17th, 2017

Leti Coordinating Project to Adapt Obstacle-Detection Technology Used in Autonomous Cars for Portable and Wearable Systems: INSPEX to Combine Knowhow of Nine European Organizations to Create Portable and Wearable Spatial-Exploration Systems February 2nd, 2017

Manufacturing platform makes intricate biocompatible micromachines January 7th, 2017

Chip Technology

A big leap toward tinier lines: Self-assembly technique could lead to long-awaited, simple method for making smaller microchip patterns March 27th, 2017

ATTOPSEMI Technology Joins FDXcelerator Program to Deliver Advanced Non-Volatile Memory IP to GLOBALFOUNDRIES 22 FDX Technology Platform: Leading-edge I-fuse brings higher reliability, smaller cell size and ease of programmability for consumer, automotive, and IoT applications March 27th, 2017

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Scientists discover new 'boat' form of promising semiconductor: GeSe Uncommon form attenuates semiconductor's band gap size March 23rd, 2017

Discoveries

Information storage with a nanoscale twist: Discovery of a novel rotational force inside magnetic vortices makes it easier to design ultrahigh capacity disk drives March 28th, 2017

A big leap toward tinier lines: Self-assembly technique could lead to long-awaited, simple method for making smaller microchip patterns March 27th, 2017

Laser activated gold pyramids could deliver drugs, DNA into cells without harm: Microstructures create temporary pores in cells March 27th, 2017

Researchers make flexible glass for tiny medical devices: Glass can bend over and over again on a nanoscale March 27th, 2017

Announcements

Information storage with a nanoscale twist: Discovery of a novel rotational force inside magnetic vortices makes it easier to design ultrahigh capacity disk drives March 28th, 2017

ATTOPSEMI Technology Joins FDXcelerator Program to Deliver Advanced Non-Volatile Memory IP to GLOBALFOUNDRIES 22 FDX Technology Platform: Leading-edge I-fuse brings higher reliability, smaller cell size and ease of programmability for consumer, automotive, and IoT applications March 27th, 2017

Leti and HORIBA Scientific to Host Webinar on Ultrafast Characterization Tool: Plasma Profiling Time-of-Flight Mass Spectrometer Tool Cuts Optimization Time In Layer Deposition and Fabrication of Wide Range of Applications March 27th, 2017

Laser activated gold pyramids could deliver drugs, DNA into cells without harm: Microstructures create temporary pores in cells March 27th, 2017

Energy

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Rice U. refines filters for greener natural gas: New study defines best materials for carbon capture, methane selectivity March 23rd, 2017

Artificial photosynthesis steps into the light: Rice University lab turns transition metals into practical catalyst for solar, other applications March 23rd, 2017

Researchers develop groundbreaking process for creating ultra-selective separation membranes: Discovery could greatly improve energy-efficiency of separation and purification processes in the chemical and petrochemical industries March 15th, 2017

Solar/Photovoltaic

Artificial photosynthesis steps into the light: Rice University lab turns transition metals into practical catalyst for solar, other applications March 23rd, 2017

New nanofiber marks important step in next generation battery development March 14th, 2017

Perovskite edges can be tuned for optoelectronic performance: Layered 2D material improves efficiency for solar cells and LEDs March 10th, 2017

Strem Chemicals and Dotz Nano Ltd. Sign Distribution Agreement for Graphene Quantum Dots Collaboration February 21st, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project