Challenge: Size Reduction and Electrical Efficiency

Taiyo Yuden originally used a palladium-silver alloy for its hybrid circuit conductors. The palladium-silver compositions were easy to handle, reproducible, and had an excellent history of use in high-volume production.

But the 100-µm line and space width limits of palladium-silver kept Taiyo Yuden engineers from designing smaller integrated circuits and achieving the size reductions and related electrical efficiency necessary for the high-frequency devices.

Solution: Low-Temperature Copper Conductors

DuPont's low-temperature copper composition allowed Taiyo Yuden to achieve 75-µm line widths within a 10% tolerance. Smaller line widths let the company reduce the size of its power amplifiers from 1.2 to 0.4 cubic centimeters. Company designers expect to reduce the size even further using the same DuPont conductor composition.

The highly conductive copper composition also provides higher conductivity and one-fifth the resistance of palladium-silver, which allows the phone to work at the necessary high frequency and gives it the power for up to 150 hours of continuous operation.

The low-temperature copper is fired in nitrogen at 600°C, compared with the 850--900°C needed for traditional conductors. Low-temperature firing lets the circuit designer combine the high conductivity and fine-line printability of copper conductors with the high precision and reliability of thick-film resistors.

For help in selecting the right material for your application, call us at 1-800-557-4505