Filter with multiple resonators having different passivation thickness distributions

1 . A filter device comprising:

a substrate having a surface;

at least one piezoelectric plate having a front surface and a back surface facing away the front surface and attached to the substrate;

a plurality of interdigital transducers (IDTs) of a plurality of resonators, respectively, each of the plurality of IDTs having a plurality of interleaved fingers on at least one surface of a respective diaphragm of a plurality of diaphragms of the at least one piezoelectric plate disposed over one or more cavities; and

at least one dielectric layer over the plurality of diaphragms and the front surface of the at least one piezoelectric plate;

wherein, for at least two resonators of the plurality of resonators, the at least one dielectric layer has a thickness distribution that includes a first thickness layer that is on and between the interleaved fingers of the respective IDTs of each of the at least two resonators and a second thickness layer over the first thickness layer, such that the first thickness layer of each of the at least two resonators is between the at least one piezoelectric plate and the second thickness layer of each of the at least two resonators, and

wherein the second thickness layer of a first resonator of the at least two resonators has a coverage distribution over the first thickness layer of the first resonator that is a different pattern in a plan view of the at least one piezoelectric plate than a pattern in the plan view of a coverage distribution of the second thickness layer over the first thickness layer of the second resonator of the at least two resonators,

wherein the first resonator comprises at least one shunt resonator and the second resonator comprises at least one series resonator, and

wherein a back-side dielectric layer is disposed on the back surface of the at least one piezoelectric plate of both the at least one shunt resonator and the at least one series resonator.

2 . The filter device of claim 1 , wherein a thickness from a top of the first thickness layer to the at least one piezoelectric plate is less than a thickness from a top of the second thickness layer to the at least one piezoelectric plate.

3 . The filter device of claim 1 , wherein an amount of dielectric material of the second thickness layer of each of at least two resonators is less than an amount of dielectric material of the first thickness layer of each of the at least two resonators.

4 . The filter device of claim 1 , wherein the pattern of the coverage distribution of the second thickness layer of the second resonator includes a different number of one or more linear stripes or a different thickness of the one or more linear stripes than the pattern of the coverage distribution of the second thickness layer of the first resonator.

5 . The filter device of claim 1 , wherein the at least one dielectric layer includes SiO 2 .

6 . The filter device of claim 1 , wherein the plurality of resonators are arranged on a same die.

7 . The filter device of claim 1 , wherein the coverage distribution of the second thickness layer over the first thickness layer of the shunt resonator has a percentage of coverage on the first thickness layer that is different than a percentage of coverage of the coverage distribution of the second thickness layer on the first thickness layer of the series resonator.

8 . The filter device of claim 1 , wherein the pattern of the coverage distribution of the second thickness layer over the first thickness layer of the first resonator comprises an asymmetric distribution in the plan view with respect to a center portion of the first resonator.

9 . The filter device of claim 1 , wherein the plurality of IDTs are on a first surface of each of the plurality of diaphragms, respectively, and the at least one dielectric layer is on the plurality of IDTs.

10 . The filter device of claim 1 , wherein the first thickness layer and the second thickness layer over the first thickness layer of the at least one dielectric layer are formed of a single continuous dielectric material.

11 . The filter device of claim 4 , wherein at least one of the one or more linear stripes of the coverage distribution of the second thickness layer of each of the first resonator and the second resonator extend in a direction transverse to a direction in which at least one finger of the plurality of interleaved fingers extend of the respective IDTs of the first resonator and the second resonator.

12 . A filter device comprising:

a substrate having a surface;

at least one piezoelectric plate having a front surface and a back surface facing away the front surface and attached to the substrate;

a plurality of interdigital transducers (IDTs) of a plurality of resonators, respectively, that each have a plurality of interleaved fingers on at least one surface of a respective diaphragm of a plurality of diaphragms of the at least one piezoelectric plate disposed over one or more cavities; and

at least one dielectric layer over the plurality of diaphragms and the front surface of the at least one piezoelectric plate;

wherein the at least one dielectric layer of at least one first resonator of the plurality of resonators has a thickness distribution that includes a dielectric base having a uniform distribution and a first dielectric pattern on the dielectric base, such that the dielectric base of the at least one first resonator is between the interleaved fingers of the respective IDT and between the at least one piezoelectric plate and the first dielectric pattern of the at least one first resonator,

wherein the at least one dielectric layer of at least one second resonator of the plurality of resonators has a thickness distribution that includes a dielectric base having a uniform distribution and a second dielectric pattern on the dielectric base, such that the dielectric base of the at least one second resonator is between the interleaved fingers of the respective IDT and between the at least one piezoelectric plate and the second dielectric pattern of the at least one first resonator,

wherein the first dielectric pattern in a plan view of the at least one piezoelectric plate is a different pattern than the second dielectric pattern in the plan view,

wherein the at least one first resonator comprises at least one shunt resonator and the at least one second resonator comprises at least one series resonator, and

wherein a back-side dielectric layer is disposed on the back surface of the at least one piezoelectric plate of both the at least one shunt resonator and the at least one series resonator.

13 . The filter device of claim 12 , wherein the at least one dielectric layer includes SiO 2 .

14 . The filter device of claim 12 , wherein the plurality of resonators are arranged on a same die.

15 . The filter device of claim 12 , wherein the first and second dielectric patterns include a different number of one or more linear stripes from each other or a different thickness of the one or more linear stripes from each other.

16 . The filter device of claim 12 , wherein the plurality of IDTs are on a first surface of each of the respective diaphragms and the at least one dielectric layer is on the plurality of IDTs.

17 . The filter device of claim 12 ,

wherein the dielectric base and the first dielectric pattern of the at least one first resonator is a single continuous dielectric material, and

wherein the dielectric base and the second dielectric pattern of the at least one second resonator is a single continuous dielectric material.