Patent ID: 7459094
Filing Date: 2008-12-02
Classification: C23F,H01L,H03H

Abstract:
1. A method for making a surface acoustic wave (SAW) device package that includes a SAW die having a piezoelectric substrate, and transmitting and receiving transducers and a cap formed on the substrate, the cap having a peripheral wall and a cover wall which cooperate with the substrate to define an embedded air cavity thereamong, said method comprising the steps of: forming a pattern of lift-off layer on a wafer surface of a wafer through lithography techniques; forming a metal layer on the wafer surface of the wafer and the lift-off layer through metallization techniques; removing the lift-off layer and the metal layer on the lift-off layer by dissolving the lift-off layer in a solution so as to form a pattern of the metal layer, that defines the transmitting and receiving transducers of the SAW die, on the wafer surface of the wafer; forming a pattern of a first photo sensitive layer, which defines the peripheral wall of the cap of the SAW die, on the metal layer and the wafer surface of the wafer through lithography techniques; forming a pattern of a second photo sensitive layer, which defines the cover wall of the cap of the SAW die, on the first photo sensitive layer through lithography techniques; curing the first and second photo sensitive layers; dicing the wafer into SAW dies; and encapsulating the SAW dies with a molding compound.