Super-Adhesive Bonding of Metal to Polyimide
Original Publication Date: 1987-Dec-01
Included in the Prior Art Database: 2005-Feb-02
Polyimide is commonly used as a dielectric in various packaging products in which the adhesion of metal lines to the polyimide is critical. The process described gives improved adhesion for evaporated or sputtered chromium metallurgy. The process consists of RF sputter etching of the polyimide surface, preheating to 400oC and then in-situ sputter depositing successive layers of chromium (Cr), copper (Cu), and chromium (Cr). The argon pressure used in the sputter etching and sputter depositing is in the range 8-18 mTorr. The RF power density used in the sputter etching is 3-4 W/in2 . Typical sputter etching times have been 10 minutes. During sputter etching of polyimide, a very thin metallic layer (Cr) deposits on the polyimide surface.