Monolithic duplexer and fabrication method thereof

Abstract

A monolithic duplexer and a fabrication method thereof. The monolithic duplexer includes a device wafer, a plurality of elements distanced from each other on a top portion of a device wafer, first sealing parts formed on the top portion of the device wafer, and a plurality of first ground planes formed between the plurality of elements. A cap wafer is also provided having an etched area for packaging the device wafer, a plurality of protrusion parts, a plurality of ground posts, and cavities. Second sealing parts are formed on a bottom portion of the protrusion parts, and a plurality of second ground planes cover the plurality of ground posts. Via holes vertically penetrate the cap wafer to connect to the plurality of the second ground planes, and ground terminals are formed on top portions of the via holes. The first sealing parts and the first ground planes are attached to the second sealing parts and the second ground planes, respectively.