Acoustic resonator and method of manufacturing the same
An acoustic resonator includes: a substrate; a resonance part including a lower electrode, a piezoelectric layer, and an upper electrode sequentially stacked on the substrate, and a frame formed on the upper electrode along an edge of the upper electrode; and a trench part formed in at least one side of the resonance part and making a thickness of the resonance part asymmetrical.
1. An acoustic resonator comprising:
a substrate;
a resonance part comprising
a lower electrode, a piezoelectric layer, and an upper electrode sequentially stacked on the substrate, and
a frame formed on the upper electrode along an edge of the upper electrode; and
a trench part formed in the resonance part, along only two sides of the upper electrode, and forming a thickness of the resonance part to be asymmetrical.
2. The acoustic resonator of claim 1 , wherein the trench part is formed in a shape of a groove in the upper electrode.
3. The acoustic resonator of claim 2 , wherein:
the upper electrode is formed in a quadrangular shape, and
the trench part is disposed parallel to the two sides of the upper electrode.
4. The acoustic resonator of claim 3 , wherein the trench part is disposed continuously along the two sides of the upper electrode.
5. The acoustic resonator of claim 4 , wherein a portion of the trench part disposed along one of the two sides and a portion of the trench part disposed along another of the two sides have different widths.
6. The acoustic resonator of claim 1 , wherein the trench part is formed as a linear groove along an inner wall of the frame.
7. The acoustic resonator of claim 1 , wherein a width of the trench part is greater than a depth of the trench part.
8. The acoustic resonator of claim 1 , wherein the trench part is formed at different depths depending on a position of the trench part.
9. The acoustic resonator of claim 1 , further comprising an insulation protecting layer stacked on the upper electrode, wherein the trench part is formed in a shape of a groove by a removed portion of the insulation protecting layer.
10. The acoustic resonator of claim 9 , wherein a bottom surface of the trench part is formed by the insulation protecting layer.
11. The acoustic resonator of claim 1 , further comprising a second trench part formed in the lower electrode, wherein the piezoelectric layer is filled in the second trench part.
12. A method to manufacture an acoustic resonator, comprising:
forming a sacrificial layer on a substrate;
sequentially stacking a lower electrode and a piezoelectric layer on the sacrificial layer;
forming an upper electrode on the piezoelectric layer, wherein the upper electrode comprises a trench part disposed along only two sides of the upper electrode; and
removing the sacrificial layer.
13. The method of claim 12 , wherein the forming of the upper electrode comprises:
forming a first electrode layer on the piezoelectric layer; and
forming a second electrode layer on a region of an upper surface of the first electrode layer excluding the trench part.
14. The method of claim 13 , further comprising forming a frame layer on the second electrode layer.
15. The method of claim 14 , wherein the trench part is disposed in the upper electrode along only two adjacent sides of the frame layer.
16. The method of claim 12 , wherein the forming of the upper electrode comprises:
forming an electrode layer on the piezoelectric layer; and
forming the trench part by removing a portion of the electrode layer.
17. The method of claim 16 , further comprising forming a frame layer on the electrode layer.
18. The acoustic resonator of claim 1 , wherein the two sides are adjacent to each other.
19. The acoustic resonator of claim 1 , wherein the trench part is formed along less than 50% of a perimeter of the upper electrode.
20. An acoustic resonator comprising:
a substrate;
a resonance part comprising
a lower electrode, a piezoelectric layer, and an upper electrode sequentially stacked on the substrate, and
a frame formed on the upper electrode along an edge of the upper electrode; and
a trench part formed in the resonance part, along sides of the upper electrode, and forming a thickness of the resonance part to be asymmetrical,
wherein a portion of the trench part disposed along one of the sides and a portion of the trench part disposed along another of the sides have different widths.