Characterisation and reliability evaluation of a verticle multichip module (NCM-TV) technique using test chips

A test chip designed for characterisation and reliability evaluation of a 3-dimensional vertical multichip module (MCM-V) technique and it's application in ESPRIT Project TRIMOD-TRI-dimensional multichip MODules will be described. The desipi of the test chip itself, of technology demonsttator (TD) modules incorporating the test chips and the results of thermal, thermomechanical and electrical characterisation and reliability testing will be presented. In addition, the correlation between thermal and thermomechanical modelling and measured results from the TD modules will be discussed. TRIMOD (ESPRIT Project 6490) involves the design and fabrication of modules to demonstrate the capabilities and to evaluate the technological Umits of a novel three-dimensional MCM-V technique based on vertical stacking of ICs in a plastic package, with intercoimections made on the faces of the resultant plastic "cube". Three "technological demonstrator" test vehicles, incorporating custom designed test ICs, were designed and fabricated to evaluate the technological limits of the MCM-V technique. The silicon test chip (see Figure 1) is 10 x 5 mm. In size (chosen to represent the typical ondine of a memory IC) and incorporates diffused resistors for power dissipation and diodes for temperature measurement, triple track meander corrosion monitors, diffused resistor strain gauges and paired bond pads wire-bond daisy chains. The technological demonstrators consist of two thermal/corrosion/daisy chain characterisation MC-V's, the difference between them being the chip interconnection technique, and one thermomechanical stress characterisation MCM-V. Sets of all three technological demonsti-ators are now being subjected to characterisation before and after extensive environmental stress testing and final results are expected in the second quarter of 1994. The detailed final test results will be presented.