Planarization treatment of pressure sensitive adhesive for rigid-to-rigid substrate lamination

The present invention is a process for performing a planarization treatment of pressure-sensitive adhesive (PSA). The process includes positioning a first substrate onto a support surface of a planarization tool. The process further includes placing at least one layer of PSA onto the first substrate. The process further includes positioning a second substrate onto the layer(s) of PSA. The process further includes applying a pressure to the second substrate via a flexible membrane, said pressure being applied in a generally uniform, unidirectional and localized manner. Further, the applied pressure flattens the PSA between the first substrate and the second substrate for promoting suitability of the PSA for use in rigid-to-rigid lamination processes.