FRACTURING OF INDUSTRIAL DIAMOND PLATES

Indentation hardness and three-point bend tests were performed on perf orated synthetic diamond substrates designed for use in a three-dimens ional cube computer architecture based on interconnected stacking of m ultichip modules. The fracture strengths in bending of two substrate m aterials, with and without laser drilled interconnect ''via holes'', w ere correlated with optical and scanning electron microscope (SEM) obs ervations of the fracture surfaces, thus providing for matching of fra cture strengths with different growth microstructures with in the plat es and, also, with the extent of weakening produced by the via holes. The relatively high strength levels, characteristic of diamond materia l, were found to be lowered somewhat either by a filamentary pattern o f growth fissures in one material or less so by apparent cleavage frac turing among textured grains in a second material. In the latter case, the technique of fracture surface topography analysis (FRASTA) provid ed evidence of plastic flow having occurred during fracturing.