Effect of polyimide processing on multichip glass ceramic module fabrications

Contaminants introduced during polyimide (PI) processing cause open and short circuit defects of multichip glass ceramic modules (MCM-D). Fibers, metal flakes, particles and polishing scratches expose the PI to the hot N-methylpyrollidinone (NMP) solvent which diffuses to the polyimide/copper wiring structures causing them to swell. The amount of damage depends on the rate of solvent diffusion, process temperature, lift-off time and the amount of PI swelling during processing.