Pulse CO/sub 2/ laser drilling of green alumina ceramic

Ceramics are used as thermal conductors and electrical insulators in integrated circuit packaging. We have investigated TEA CO/sub 2/ laser drilling of green alumina ceramic sheets consisting predominantly of alumina with approximately 10% PVB (polyvinyl butyral) as the polymer binder. Experiments with 9.5 and 10.6 /spl mu/m wavelengths show that the holes made with a 9.5 /spl mu/m CO/sub 2/ laser beam, where a larger percentage of the total laser energy is deposited directly into the polymer binder, are smaller, more straight-sided and cleaner.