A liftoff process using edge detection (LOPED)

A process for liftoff patterning has been examined with particular emphasis on the process window for manufacturing. Traditional liftoff techniques, which use reentrant resist profiles and evaporation for metal deposition, have the advantage of simplicity and infinite selectivity; however, the need for directional deposition is in conflict with the step coverage requirement of VLSI. A liftoff process using edge detection (LOPED) is described that can pattern thin film deposits with good step coverage. Some guidelines have been developed for the LOPED process to assure successful patterning. A process window is shown as an example for a specific combination of film thicknesses. The potential of the LOPED process is demonstrated for both metallization and trench isolation