SBAR structures and method of fabrication of SBAR.FBAR film processing techniques for the manufacturing of SBAR/BAR filters
First Claim
1. An acoustical resonator comprising:
- a first electrode comprising a conducting sheet having a RMS variation in height of less than 2 μ
m;
a second electrode comprising a conducting sheet;
a layer of piezoelectric material sandwiched between said first and second electrodes.
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Reexamination
Accused Products
Abstract
An acoustical resonator and a method for making the same. A resonator according to the present invention includes a layer of piezoelectric material sandwiched between first and second electrodes. The first electrode includes a conducting sheet having a RMS variation in height of less than 2 μm. The resonator bridges a cavity in a substrate on which the resonator is constructed. The resonator is constructed by creating a cavity in the substrate and filling the same with a sacrificial material that can be rapidly removed from the cavity after the deposition of the various layers making up the resonator. The surface of the filled cavity is polished to provide a RMS variation in height of less than 0.5 μm. The first electrode is deposited on the polished surface to a thickness that assures that the RMS variation in height of the metallic layer is less than 2 μm. The piezoelectric layer is deposited on the first electrode and the second electrode is then deposited on the piezoelectric layer. The sacrificial material is then removed from the cavity by opening vias into the cavity and removing the material through the vias. The preferred sacrificial material is phophor-silica-glass.
308 Citations
13 Claims
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1. An acoustical resonator comprising:
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a first electrode comprising a conducting sheet having a RMS variation in height of less than 2 μ
m;a second electrode comprising a conducting sheet; a layer of piezoelectric material sandwiched between said first and second electrodes. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for fabricating an acoustical resonator on a substrate having a top surface, said method comprising steps of:
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generating a depression in said top surface; filling said depression with a sacrificial material, said filled depression having an upper surface level with said top surface of said substrate, said upper surface having a RMS variation in height of less than 0.5 μ
m;depositing a first electrode on said upper surface; depositing a layer of piezoelectric material on said first electrode; depositing a second electrode on said layer of piezoelectric material; and removing said sacrificial material from said depression. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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Specification