Circuit board materials may like it hot (or not)

Jun 09, 2006

Electrical circuits may act differently in Arizona than they do in Alaska--potentially affecting the performance of computers and other electronics. A new technique identifies and quantifies an important cause of this temperature sensitivity.

Researchers at the National Institute of Standards and Technology and DuPont Electronic Technologies (Research Triangle Park, N.C.) have demonstrated a nondestructive method for measuring how temperature affects the electrical properties of three common circuit board materials (ceramic, polymer and glass).

The work, described at a recent conference,* provides manufacturers with an accurate technique for measuring high-frequency electrical properties of substrates without cutting up the material--enabling faster, less expensive and easier testing--as well as a tool for designing circuits and substrates with improved performance.

NIST has been working with ceramic and printed-wiring board manufacturers for five years to develop the technique. They previously have used the method to measure changes in electrical properties as substrates are subjected to different electromagnetic frequencies. The work is important to the electronics industry because the performance of electrical circuits depends in part on the electrical properties of the substrate.

The apparatus used in the experiments, the split-cylinder resonator, was originally designed elsewhere, but NIST developed a mathematical model that improves its accuracy and extends its frequency range. The model has been approved as an industry standard. A thin piece of substrate is placed between two halves of a cylindrical cavity--smaller than a coffee mug--inside an environmental chamber.

A computer analyzes the changes in the microwave-range resonant frequency as the chamber temperature changes from -50 to 100 degrees Celsius (-58 to 212 degrees Farenheit). As the temperature rose, an important electrical property called loss tangent (a measure of electrical losses in an insulating material) fell in glass, generally increased in the organic substrate, and remained stable in one type of ceramic while rising slightly in another.

*M.D. Janezic, T. Mobley, and D. Amey. 2006. Temperature-dependent complex permittivity measurements of low-loss dielectric substrates with a split-cylinder resonator. Presented at IMAPS/ACerS International Conference and Exhibition of Ceramic Interconnect and Ceramic Microsystems Technologies (CICM), April 24-27, 2006, Denver, Colo.

Source: NIST

Explore further: MediaTek SoC to boost 64-bit Android devices

add to favorites email to friend print save as pdf

Related Stories

Scientists enlist big data to guide conservation efforts

2 minutes ago

Despite a deluge of new information about the diversity and distribution of plants and animals around the globe, "big data" has yet to make a mark on conservation efforts to preserve the planet's biodiversity. ...

66-yard crater appears in far northern Siberia

1 hour ago

Russian scientists say they believe a 60-meter (66-yard) wide crater discovered recently in far northern Siberia could be the result of changing temperatures in the region.

Mexico reports first litter of wolf cubs in the wild

2 hours ago

The first known litter of Mexican gray wolves has been born in the wild as part of a three-year effort to re-introduce the subspecies to a habitat where it disappeared three decades ago, Mexican officials reported Thursday.

Recommended for you

Apple's fiscal 3Q earnings top analyst forecasts

5 hours ago

Apple's growth prospects are looking brighter as anticipation builds for the upcoming release of the next iPhone, a model that is expected to cater to consumers yearning for a bigger screen.

Putin signs law seen as crimping social media

6 hours ago

President Vladimir Putin on Tuesday signed a law requiring Internet companies to store all personal data of Russian users at data centres in Russia, a move which could chill criticism on foreign social networking ...

User comments : 0