Abstract
Spreading of glass frits on alumina substrate for hybrid IC applications has been studied. A PbO-SiO2 binary glass containing 75% PbO was chosen as a typical composition and Al2O3, ZnO, MgO and B2O3 were added thereto. In addition to alumina substrate containing 96 and 99% Al2O3, sapphire and fused SiO2 plates were used for comparison. The spreading was determined from the area of glass frit on the substrates as a function of heating time and temperature. The reaction was examined by microscopy and EPMA. The results are summarized as follows.
(1) The spreading increased with increasing temperature and time for all the glass compositions. The spreading was promoted by ZnO and MgO addition but suppressed by Al2O3 and B2O3 addition.
(2) All the additives increased the thickness of the reaction layer, most pronounced With ZnO, followed in the decreasing order, by Al2O3, MgO and B2O3. ZnAl2O4 was the only crystalline product observed in the reaction.
(3) Comparison of spreading behavior on different substrates indicated that the contribution of glass-substrate interactions to the spreading depends on the glass composition.
