06548942 is referenced by 101 patents and cites 3 patents.

An acoustic reflector (

48

) is applied over a thin-film piezoelectric resonator (

41, 61

) which is supported on a semiconductor or semiconductor-compatible substrate (

42, 62

) of a microelectronic device (

40, 60

), enabling an encapsulant (

49

) to be applied over the reflector-covered resonator without acoustically damping the resonator. In one embodiment, alternating high and low acoustic impedance layers (

51, 53 . . . 55

) of one-quarter wavelength thicknesses constructively reflect the resonating wavelength to make an encapsulant in the form of an inexpensive plastic molding compound appear as a “clamping” surface to a resonator (

41

) peripherally supported over an opening (

43

) on a silicon substrate (

42

). In another embodiment, an encapsulant- and reflector-covered resonator (

61

) is mechanically supported above a second reflector (

68

) which eliminates the need for peripheral support, making substrate (

68

) also appear as a clamping surface. The invention enables low cost plastic packaging of resonators and associated circuitry on a single monolithic structure. A radio frequency transceiver front-end application is given as an exemplary implementation.

Title
Encapsulated packaging for thin-film resonators and thin-film resonator-based filters having a piezoelectric resonator between two acoustic reflectors
Application Number
9/571097
Publication Number
6548942 (B1)
Application Date
May 15, 2000
Publication Date
April 15, 2003
Inventor
Carl M Panasik
Garland
TX, US
Agent
Frederick J Telecky Jr
US
W James Brady III
US
Pedro P Hernandez
US
Assignee
Texas Instruments Incorporated
TX, US
IPC
H01L 41/04
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