Fabricating methods for air-gap type FBARs and duplexers including securing a resonating part substrate to a cavity forming substrate
First Claim
1. A method of fabricating an air-gap type film bulk acoustic resonator (FBAR), comprising:
- forming a resonance part on a first substrate, the forming of the resonance part including sequentially providing a first dielectric layer, a first electrode, a piezoelectric layer, and a second electrode on the first substrate;
forming a cavity in a second substrate;
securing the first substrate with the second substrate so that the resonance part is located in the cavity;
packaging including removing the first substrate after the securing; and
exposing part of the first and second electrodes to form a pad by removing corresponding portions of the first dielectric layer part of the resonance part.
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Abstract
An air-gap type film bulk acoustic resonator (FBAR) is created by securing two substrate parts, one providing a resonance structure and the other providing a separation structure, i.e., a cavity. When the two substrate parts are secured, the resonance structure is over the cavity, forming an air gap isolating the resonant structure from the support substrate. The FBAR may be used to form a duplexer, which includes a plurality of resonance structures, a corresponding plurality of cavities, and an isolation part formed between the cavities. The separate creation of the resonance structures and the cavities both simplifies processing and allows additional elements to be readily integrated in the cavities.
41 Citations
19 Claims
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1. A method of fabricating an air-gap type film bulk acoustic resonator (FBAR), comprising:
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forming a resonance part on a first substrate, the forming of the resonance part including sequentially providing a first dielectric layer, a first electrode, a piezoelectric layer, and a second electrode on the first substrate; forming a cavity in a second substrate; securing the first substrate with the second substrate so that the resonance part is located in the cavity; packaging including removing the first substrate after the securing; and exposing part of the first and second electrodes to form a pad by removing corresponding portions of the first dielectric layer part of the resonance part. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of fabricating a single-chip duplexer using an air-gap type film bulk acoustic resonator (FBAR) filter, comprising:
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forming a first substrate part having first and second resonance parts formed at predetermined intervals on a surface of a first substrate; forming a second substrate part including forming first and second cavities at the predetermined intervals on a second substrate, and forming an isolation part between the first and second cavities; securing the first substrate part and the second substrate part so that the isolation part is located between the first and second resonance parts and the first and second resonance parts are over the first and second cavities, respectively; and removing the first substrate of the first substrate part after the securing. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification