Title :
Plated copper on ceramic for power hybrid applications
Author :
Weeks, Richard ; Johnson, R. Wayne ; Hopkins, Douglas ; Muir, James ; Williams, Janette R.
Author_Institution :
Dept. of Electr. Eng., Auburn Univ., AL, USA
Abstract :
A technique for plating copper onto ceramic with top layers of nickel, gold, and/or solder is described. The adhesion mechanism of the copper is an interlocking of the film and ceramic surface to form a mechanical bond. Soldered adhesion of the copper did not degrade during high-temperature storage or thermal cycling. A nickel barrier between the plated copper and solder inhibits diffusion and intermetallic formation. Testing of small-diameter gold and large-diameter aluminum wire bonds after high-temperature storage demonstrated the reliability of wire bonding to the Cu/Ni/Au metallization. While a small percentage of bond lifts occurred among the aluminum-wire-bond samples stored at 200°C, the bond strengths were high and there was no increase in series bond resistance. Preliminary evaluation of a screen-printable polyimide encapsulant revealed pinholes in the cured film. Alternate polyimide formulations are being evaluated. A 2-MHz, 100-W DC-DC converter was fabricated to demonstrate the use of plated copper on ceramic substrate technology
Keywords :
copper; electroplated coatings; encapsulation; hybrid integrated circuits; integrated circuit technology; metallisation; power convertors; power integrated circuits; soldering; 100 W; 2 MHz; 200 C; Cu-Au; Cu-Ni; Cu-Ni-Au; Cu-PbSn; DC-DC converter; bond resistance; bond strengths; ceramic substrate technology; metallisation; plating technique; power circuit hybridisation; screen-printable polyimide encapsulant; soldered adhesion; thermal cycling; wire bonding; Adhesives; Bonding; Ceramics; Copper; Gold; Intermetallic; Nickel; Polyimides; Thermal degradation; Wire;
Conference_Titel :
Electronic Components Conference, 1989. Proceedings., 39th
Conference_Location :
Houston, TX
DOI :
10.1109/ECC.1989.77803
