Filter component with passive element and radio-frequency module
A filter component with a passive element includes a filter substrate, an elastic wave filter including an elastic wave resonator in a predetermined region of one main surface of the filter substrate, and a support substrate on another main surface of the filter substrate, wherein a passive element is provided in or on a support substrate, the passive element includes a wiring electrode and is electrically connected to the elastic wave filter.
1. A filter component with a passive element, comprising:
a filter substrate;
an elastic wave filter including an elastic wave resonator in a predetermined region of one main surface of the filter substrate; and
a support substrate disposed on another main surface of the filter substrate; wherein
a passive element is provided in or on the support substrate; and
the passive element includes a wiring electrode and is electrically connected to the elastic wave filter; wherein
the filter substrate is a double layer substrate including a high acoustic velocity layer and a piezoelectric layer;
the piezoelectric layer is disposed on one main surface of the high acoustic velocity layer, and the support substrate is disposed on another main surface of the high acoustic velocity layer;
the elastic wave filter is a SAW filter which includes the elastic wave resonator including comb-shaped electrodes disposed on one main surface of the piezoelectric layer; and
an acoustic velocity of bulk waves propagating in the high acoustic velocity layer is faster than an acoustic velocity of elastic waves propagating on the piezoelectric layer.
2. The filter component according to claim 1 , wherein a thickness of the filter substrate is less than a thickness of the support substrate.
3. The filter component according to claim 1 , wherein a thickness of the filter substrate is less than about 100 μm.
4. The filter component according to claim 1 , wherein, when a pitch of the comb-shaped electrodes is p μm, a thickness t of the piezoelectric layer is expressed by:
0.05· p μm≤ t≤ 100 μm.
5. The filter component according to claim 1 , wherein the support substrate is a multilayer substrate.
6. The filter component according to claim 5 , wherein the passive element is integrated within the multilayer substrate.
7. The filter component according to claim 1 , further comprising:
an insulating layer surrounding the predetermined region of the one main surface of the filter substrate;
a cover layer disposed on the insulating layer so as to define, together with the insulating layer, a surrounded space between the filter substrate and the cover layer; and
an external-connecting terminal electrode that is exposed on a main surface of the cover layer on a side opposite to another main surface of the cover layer facing the space and that is electrically connected to the elastic wave filter.
8. The filter component according to claim 1 , further comprising:
an insulating layer surrounding the predetermined region of the one main surface of the filter substrate;
a cover layer disposed on the insulating layer so as to define, together with the insulating layer, a surrounded space between the filter substrate and the cover layer; and
an external-connecting terminal electrode that is provided on a main surface of the support substrate on a side opposite to another main surface of the support substrate facing the filter substrate and that is electrically connected to the elastic wave filter.
9. The filter component according to claim 1 , wherein, in adjacent to the filter substrate, another filter substrate is provided on the support substrate.
10. A radio-frequency module comprising:
the filter component according to claim 1 ; and
a module substrate on which the filter component is mounted.
11. The radio-frequency module according to claim 10 , wherein another passive element connected to the elastic wave filter is provided in or on the module substrate.
12. The filter component according to claim 1 , wherein the passive element includes an inductor or a capacitor and adjusts filter characteristics of the elastic wave filter.
13. The filter component according to claim 1 , wherein
the support substrate is a multilayer substrate including a plurality of dielectric layers; and
the passive element includes an inductor or a capacitor that is defined by conductive patterns disposed within the multilayer substrate.
14. The filter component according to claim 1 , further comprising:
a via-conductor located in the filter substrate; wherein
the via conductor electrically connects the wiring electrode of the passive element to the elastic wave filter.
15. The filter component according to claim 1 , further comprising:
a bonding wire electrically connecting the wiring electrode of the passive element to the elastic wave filter.
16. The filter component according to claim 1 , wherein
the wiring electrode of the passive element is disposed on a main surface of the support substrate on a side opposite to another main surface of the support substrate that faces the filter substrate.
17. The filter component according to claim 16 , further comprising an interlayer-connecting conductor disposed such that the interlayer-connecting conductor passes through the filter substrate and the support substrate so as to connect a terminal electrode located on the one main surface of the filter substrate with the wiring electrode of the passive element.