Extensive electrical and thermal characterization of an MCM-D technology

In this paper, it is shown the work carried out on thermal characterization of the main materials employed in the deposited-type multichip module (MCM-D) technology. In this technology, silicon chips are mounted onto a silicon substrate by a flipchip technique. The substrates can be either passive with interconnection lines, Rs, Cs, and Ls or active with complementary metal oxide semiconductor (CMOS) technology cells. The metals used in this technology are aluminum for interconnection purposes, tantalum silicide for making resistors and a multilayer of wettable metal for solder connection. Measurements of sheet resistance and contact resistance versus temperature in the range of -28°C to 100°C of the metals used in the technology are shown. A set of classic test structures such as Kelvin contacts, cross bridge resistors (CBR), and Van der Pauw structures have been used for this purpose as well as a new Kelvin-like structure to test the contact resistance of the Flip Chip connection through the ball. This structure has been proven to be very sensitive allowing the measurement of changes in ball resistance in the range of mΩ. A thermal model of the MCM package has been obtained, taking into account all the thermal resistances added by this kind of package