Improved Evaporated Copper to Polyimide Bond
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-07
The failure of the bond between a polyimide layer and copper evaporated onto the polyimide is due to (or is co-existent with) columnar metallurgy. Noncolumnar metallurgy results if prior to the evaporation, the polyimide layer is treated at a higher temperature than that used in the evaporation process. This can be done in several ways. In one method, the elevated temperature is done during the C-cure phase of the polyimide in an inert atmosphere, such as nitrogen. In another method, the polyimide is C-cured in a vacuum at a conventional temperature. It is believed that the absence of outgassing prevents columnar growth. In the first method described, the polyimide is cured at a higher temperature so that a more complete imidization occurs.