FBAR structure and manufacturing method of same
A film bulk acoustic resonator (FBAR) structure includes a top electrode, a piezoelectric layer disposed below the top electrode, a bottom electrode disposed below the piezoelectric layer, a dielectric layer disposed below the bottom electrode, a bonding substrate disposed below the dielectric layer, a bottom cap wafer disposed below the bonding substrate, and a cavity disposed below the bottom electrode and formed by the dielectric layer, the bonding substrate, and the bottom cap wafer.
1. A film bulk acoustic resonator (FBAR) structure, comprising:
a top electrode;
a piezoelectric layer disposed below the top electrode;
a bottom electrode disposed below the piezoelectric layer;
a dielectric layer disposed below the bottom electrode;
a bonding substrate disposed below the dielectric layer;
a bottom cap wafer disposed below the bonding substrate; and
a cavity disposed below the bottom electrode and formed by the dielectric layer, the bonding substrate, and the bottom cap wafer,
wherein the cavity has a top end, a bottom end, and sidewalls between the top end and the bottom end and extending in a direction crossing extending directions of the top end and the bottom end,
the sidewalls of the cavity are formed by the dielectric layer and the bonding substrate, and
the bottom end of the cavity is formed by the bottom cap wafer.
2. The FBAR structure of claim 1 , wherein at least one edge of the bottom
electrode is disposed within the cavity.
3. The FBAR structure of claim 1 , wherein a vertical projection of at least one edge of the top electrode is disposed within the cavity.
4. The FBAR structure of claim 1 , further comprising at least one of a top raised structure disposed above the top electrode and along an edge of the top electrode, or a bottom raised structure disposed below the bottom electrode and along an edge of the bottom electrode.
5. The FBAR structure of claim 1 , further comprising:
a top passivation layer disposed above the top electrode; and
a bottom passivation layer disposed below the bottom electrode.
6. The FBAR structure of claim 5 , wherein each one of the top passivation layer and the bottom passivation layer includes silicon nitride (SiN), aluminum nitride (AlN), silicon oxide (SiO 2 ), silicon oxynitride (SiNO), or a stacked combination of two or more of those materials.
7. The FBAR structure of claim 5 , further comprising:
a bottom electrode contact layer disposed above the piezoelectric layer and electrically connected with the bottom electrode via a bottom electrode contact window formed in the piezoelectric layer; and
a top electrode contact layer disposed above the top passivation layer and electrically connected with the top electrode via a top electrode contact window formed in the top passivation layer.
8. The FBAR structure of claim 7 , wherein each one of the bottom electrode contact layer and the top electrode contact layer includes aluminum (Al), copper (Cu), gold (Au), titanium (Ti), tungsten (W), platinum (Pt), or a stacked combination of two or more of those materials.
9. The FBAR structure of claim 1 , further comprising:
a bonding layer disposed between the bonding substrate and the bottom cap wafer,
wherein the bonding substrate is bonded to the bottom cap wafer via the bonding layer.
10. The FBAR structure of claim 9 , wherein the bonding layer includes a single layer of bonding material.
11. The FBAR structure of claim 9 , wherein the bonding layer includes an opening connected with the cavity.
12. The FBAR structure of claim 9 , wherein the bonding layer includes at least an upper bonding layer and a lower bonding layer.
13. The FBAR structure of claim 12 , wherein the upper bonding layer includes an opening connected with the cavity.
14. The FBAR structure of claim 9 , wherein the bonding layer includes silicon oxide, silicon nitride, ethyl silicate, dry film, or a stacked combination of two or more of those materials.
15. The FBAR structure of claim 1 , wherein the piezoelectric layer includes aluminum nitride (AlN), zinc oxide (ZnO), lithium niobate (LiNbO 3 ), lithium tantalate (LiTaO 3 ), lead zirconate titanate (PZT), barium strontium titanate (BST), or a stacked combination of two or more of these materials.
16. The FBAR structure of claim 1 , wherein the top electrode and the bottom electrode include molybdenum (Mo), aluminum (Al), copper (Cu), platinum (Pt), tantalum (Ta), tungsten (W), palladium (Pd), ruthenium (Ru), or a stacked combination of two or more of these materials.
17. The FBAR structure of claim 1 , wherein the dielectric layer includes pure silicon oxide, phosphor silicate glass (PSG), or boron phosphor silicate glass (BPSG).
18. The FBAR structure of claim 1 , wherein the bonding substrate includes silicon (Si).
19. The FBAR structure of claim 1 , wherein the bottom cap wafer includes silicon (Si), silicon carbide (SiC), sapphire (Al 2 O 3 ), or a stacked combination of two or more of those materials.