Featured Research

from universities, journals, and other organizations

Microelectronics: A tougher seal for rugged environments

Date:
February 27, 2013
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
Sensors used in harsh conditions, such as deep-sea oil wells, must withstand extreme temperatures and pressures for hundreds of hours without failing. Researchers in Singapore have investigated two metal alloys that could give micro-electromechanical system (MEMS) sensors better protection in the toughest environments

Sensors used in harsh conditions, such as deep-sea oil wells, must withstand extreme temperatures and pressures for hundreds of hours without failing. Vivek Chidambaram and co-workers at the A*STAR Institute of Microelectronics, Singapore, have investigated two metal alloys that could give micro-electromechanical system (MEMS) sensors better protection in the toughest environments

Typical MEMS sensors measure temperature, pressure or vibration, and they are hermetically sealed inside a strong metal casing to prevent air or moisture degrading the sensors' electronics. Chidambaram's team wanted to find cheaper, more durable alternatives to the metal solders, such as gold-tin or copper-tin, which are typically used to seal the case. They tested a 70:30 aluminum-germanium mixture, which has a melting point of about 420 C. This temperature -- the eutectic point -- is much lower than that for either metal on its own.

Unlike most conventional packaging materials, aluminum and germanium are compatible with the processes used to manufacture the MEMS. Using the aluminum-germanium sealant should make MEMS manufacturing easier and cheaper, and could also improve the device's performance, says Chidambaram.

The researchers built a stack of 4 alternating wafers of aluminum and germanium, each less than a micrometer thick, and heated the sandwich under pressure to about 400 C for 2 hours. Although the wafers did not liquefy, this "thermal aging process facilitated bonding prior to melting," explains Chidambaram. Raising the temperature to 475 C for another 2 hours fully melted the mixture, which then formed a strong seal after cooling -- a process known as transient liquid-phase bonding.

Next, the researchers used acoustic microscopy, scanning electron microscopy and X-ray spectroscopy to reveal any voids or other defects in the seals. They found that the thermal aging process improved the quality of the seal. Tests showed that it was strong enough to withstand a shear of 46 megapascals -- similar to the pressure exerted by almost half a ton per square centimeter -- and was impermeable to water. The material lost little of its strength after being exposed to 300 C for hundreds of hours.

Chidambaram and his team also tested a platinum-indium seal -- which has the highest re-melting point (894 C) of all the solders being considered for these applications -- but it lost its strength after long durations at 300 C, leaving the aluminum-germanium mixture in pole position as a better seal for MEMS. "Cost effectiveness, better thermo-mechanical properties, and its eutectic microstructure makes it an attractive alternative," says Chidambaram.

The A*STAR-affiliated researchers contributing to this research are from the Institute of Microelectronics.


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. Vivek Chidambaram, Ho Beng Yeung, Gao Shan. Development of Metallic Hermetic Sealing for MEMS Packaging for Harsh Environment Applications. Journal of Electronic Materials, 2012; 41 (8): 2256 DOI: 10.1007/s11664-012-2107-5

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Microelectronics: A tougher seal for rugged environments." ScienceDaily. ScienceDaily, 27 February 2013. <www.sciencedaily.com/releases/2013/02/130227124655.htm>.
The Agency for Science, Technology and Research (A*STAR). (2013, February 27). Microelectronics: A tougher seal for rugged environments. ScienceDaily. Retrieved August 20, 2014 from www.sciencedaily.com/releases/2013/02/130227124655.htm
The Agency for Science, Technology and Research (A*STAR). "Microelectronics: A tougher seal for rugged environments." ScienceDaily. www.sciencedaily.com/releases/2013/02/130227124655.htm (accessed August 20, 2014).

Share This




More Matter & Energy News

Wednesday, August 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Awesome New Camouflage Sheet Was Inspired By Octopus Skin

Awesome New Camouflage Sheet Was Inspired By Octopus Skin

Newsy (Aug. 19, 2014) Scientists have developed a new device that mimics the way octopuses blend in with their surroundings to hide from dangerous predators. Video provided by Newsy
Powered by NewsLook.com
Researcher Testing on-Field Concussion Scanners

Researcher Testing on-Field Concussion Scanners

AP (Aug. 19, 2014) Four Texas high school football programs are trying out an experimental system designed to diagnose concussions on the field. The technology is in response to growing concern over head trauma in America's most watched sport. (Aug. 19) Video provided by AP
Powered by NewsLook.com
Green Power Blooms as Japan Unveils 'hydrangea Solar Cell'

Green Power Blooms as Japan Unveils 'hydrangea Solar Cell'

AFP (Aug. 19, 2014) A solar cell that resembles a flower is offering a new take on green energy in Japan, where one scientist is searching for renewables that look good. Duration: 01:29 Video provided by AFP
Powered by NewsLook.com
Tiny Satellites, Like The One Tossed From ISS, On The Rise

Tiny Satellites, Like The One Tossed From ISS, On The Rise

Newsy (Aug. 18, 2014) The Chasqui I, hand-delivered into orbit by a Russian cosmonaut, is one of hundreds of small satellites set to go up in the next few years. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins