The present invention relates to a structure for mounting an integrated circuit (IC) chip.
Examples of conventional chip mounting structures are disclosed in a paper entitled "Chip carriers: coming force in packaging" by Dallas Erickson, published in March 1981 in the Electronic Packaging and Production, pp. 64 to 80, and a paper entitled "Chip Carriers--Their Application and Future Direction" by J. W. Stafford, published in June 1981 in the IEEE TRANSACTIONS ON COMPONENTS, HYBRIDS, AND MANUFACTURING TECHNOLOGY, VOL. CHMT-4, NO. 2, pp. 195 to 199.
In the conventional structures described, most of the heat generated in a chip is radiated towards the outside through a ceramic substrate on which the chip is mounted. The amount of heat radiation is, therefore, limited by the material and the configuration of the substrate, the contact area between the chip and the substrate, and other factors, so that power consumption of the chip mounted on the substrate is restricted to 1 to 2 watts at maximum. However, some high performance chips which have been developed recently to promote integration and fast operations consume power of several watts or more and, moreover, chips which consume power of even several tens of watts are expected to appear in the near future. Should such a high performance and great power consumption type chip be mounted by the conventional mounting structures, the temperature of the chip would be elevated to degrade reliability of operation and even burn the circuits built in the chip. Meanwhile, the ceramic substrate has heretofore been implemented with alumina. This brings about another problem that because the sintering temperature of alumina is higher than 1400.degree. C. (degree centigrade), gold and other metals whose melting point and resistance are low cannot be used as a wiring material forming wirings within the substrate.