Manufacturing process for thin film bulk acoustic resonator (FBAR) filters
AssigneeAvago Technologies Wireless IP (Singapore) Pte. Ltd.
InventorsRichard C. Ruby, John D. Larson, Paul D. Bradley
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Abstract
Method for fabricating an acoustical resonator on a substrate having a top surface. First, a depression in said top surface is generated. Next, the depression is filled with a sacrificial material. The filled depression has an upper surface level with said top surface of said substrate. Next, a first electrode is deposited on said upper surface. Then, a layer of piezoelectric material is deposited on said first electrode. A second electrode is deposited on the layer of piezoelectric material using a mass load lift-off process.
Claims8
A method for fabricating an acoustical resonator on a substrate having a top surface, said method comprising steps of:
- 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;
- 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 by employing a mass load lift-off process, wherein the mass load lift-off process further comprises:
- forming a mass-loading pattern over the second electrode, and depositing a mass-loading layer over the second electrode;
- and
- removing said sacrificial material from said depression.
Dependencies are inferred from the claim text.