Annealing of Polyimide Films
Original Publication Date: 1987-Aug-01
Included in the Prior Art Database: 2005-Feb-01
Annealing polymide films from 400oC to room temperature over a 12-hour period allows molecular rearrangements to form such that lower moisture solubility constants can be achieved for more densely packed polyimide. This profile allows for molecular chains to properly imidize and drive off residual solvent (NM2P) and water of condensation. The standard process has been to remove these parts to atmosphere after cure. It has been found that prolonging the cool-down time from minutes to hours, i.e., affecting an annealing process, sufficient time at temperature allows for an apparent "rearrangement" of polymide molecules to occur. This is akin to the quench and anneal processes for metals. The net change in molecular configuration is manifested by the moisture solubility constant for the polyimide.