Borosilicate glasses with high softening points for glass-ceramic/copper multilayer substrates

Abstract

We have developed borosilicate glasses with high softening points for glass-ceramic / copper multilayer substrates. The softening points of this glass ranged from 900°C to 1000°C. Glass-ceramics made using this glass barely sintered below 850°C, but sintered compactly at temperatures just below 1050°C. Green sheets made using this glass-ceramics could be fired around 850°C to remove the binder. Binder removal was caused very fast at this temperature. The glass-ceramics could be co-sintered with copper and had various advantages, such as easy binder removal, a coefficient of thermal expansion approximately equal to that of silicon, a low dielectric constant, sufficient flexural strength, and high water durability. These advantages helped make the manufacturing process of the substrate more productive.