CONTROLLED EXPANSION ORGANIC SUBSTRATE CHIP CARRIER
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2001-Nov-19
Current technology for fabrication of leadless chip carriers employs substrate materials that are made from w-fired alumina and tungsten. Additionally the covers used to mechanically protect the wire bonds and die attached to the substrate are also made from alumina. This package while very rugged and versatile is extremely expensive and requires up to 26 weeks to tool up for production quantities. Organic substrates such as conventional printed circuit board composite structures while being less expensive and requiring much less tooling time do not exhibit the required low coefficient of expansion (TCE) that is available from inorganic materials such as alumina. Also, use of conventional organic com- posite substrates just transfer the mechanical stress from the solder joints to the silicon chip.