Dry/Wet Lift-Off Process
Original Publication Date: 1984-Jul-01
Included in the Prior Art Database: 2005-Feb-04
In patterning thin film by the lift-off process, unwanted material is removed by dissolving or swelling the underlying polymer with a suitable solvent. When this polymer has been heated or irradiated during processing, this requires aggressive solvents used at high temperatures for long times. The disclosed process avoids this by etching the underlying polymer in an active, selective atmosphere and subsequently washing away the loosened metal in a mild liquid rinse. As an example of this process, aluminum-copper (AlCu) was evaporated over polysulfone photoresist patterned in a lift-off configuration. The wafers were then ashed for five minutes in 1.5 Torr oxygen at 300 watts. The chamber was preheated to 80ŒC.