Back to results
US 6,998,940 B2Granted
Component operating with bulk acoustic waves and a method for producing the component
AssigneeEpcos AG
InventorThomas Metzger
Life of this patent
Estimating the term…
Abstract
A component operating with bulk acoustic waves has a carrier substrate, a thin-film resonator and an acoustic mirror arranged between the resonator and carrier substrate. The acoustic mirror is formed by at least one high acoustic impedance layer, which is covered by a low acoustic impedance layer and the uppermost low impedance acoustic layer is planarized to form a flat planar surface on which the thin-film resonator is formed.
Claims20
A component operating with bulk acoustic waves, said component comprising:
- a carrier substrate;
- a lower electrode that faces said carrier substrate;
- an upper electrode;
- a piezoelectric layer between said lower electrode and said upper electrode, said piezoelectric layer comprising a multi-layer assembly;
- and
- an acoustic mirror between said carrier substrate and said lower electrode, said acoustic mirror comprising at least one layer with a high acoustic impedance and at least one layer with low acoustic impedance arranged in a stack, said at least one layer of low acoustic impedance including an uppermost mirror layer of said stack, said at least one layer with high acoustic impedance being formed as a structured layer, said uppermost mirror layer exhibiting a varying thickness, an upper boundary surface of said uppermost mirror layer being planar to said lower electrode, and said uppermost layer enclosing a structure of said structured layer and forming a seal with a layer of said at least one layer with a low acoustic impedance or with said carrier substrate outside of an area covered by said structure.
3 more elements
A component operating with bulk acoustic waves, said component comprising:
- a carrier substrate;
- a lower electrode that faces said carrier substrate;
- an upper electrode;
- a piezoelectric layer between said lower electrode and said upper electrode;
- an acoustic mirror between said carrier substrate and said lower electrode, said acoustic mirror comprising at least one layer with a high acoustic impedance and at least one layer with low acoustic impedance arranged in a stack, said at least one layer of low acoustic impedance including an uppermost mirror layer of said stack, said at least one layer with high acoustic impedance being formed as a structured said uppermost mirror layer exhibiting a varying thickness, an upper boundary surface of said uppermost mirror layer being planar to said lower electrode, and said uppermost layer enclosing structures of said structured layer and forming a seal with a layer of said at least one layer with a low acoustic impedance or with said carrier substrate outside of an area covered by said structure;
- an additional piezoelectric layer being formed on said upper electrode and an additional electrode on said additional piezoelectric layer;
- at least a partially permeable coupling layer between said upper electrode and said additional piezoelectric layer;
- and
- a second additional electrode between said at least a partially permeable coupling layer and said additional piezoelectric layer.
6 more elements
A component operating with bulk acoustic waves, said component comprising:
- a carrier substrate;
- a lower electrode that faces said carrier substrate;
- an upper electrode;
- a piezoelectric layer between said lower electrode and said upper electrode;
- and
- an acoustic mirror between said carrier substrate and said lower electrode, said acoustic mirror comprising at least one layer with a high acoustic impedance and at least one layer with low acoustic impedance arranged in a stack, said at least one layer of low acoustic impedance including an uppermost mirror layer of said stack, said at least one layer with high acoustic impedance being formed as a structured said uppermost mirror layer exhibiting a varying thickness, an upper boundary surface of said uppermost mirror layer being planar to said lower electrode, and said uppermost layer enclosing structures of said structured layer and forming a seal with a layer of said at least one layer with a low acoustic impedance or with said carrier substrate outside of an area covered by said structure
- said carrier substrate including a plurality of dielectric layers with at least one metallized plane being provided between successive ones of said dielectric layers.
4 more elements
A method to produce a component operating with bulk acoustic waves, said method comprising the steps of:
- providing a carrier substrate;
- forming an acoustic mirror on the carrier substrate by depositing a layer with a high acoustic impedance on the carrier substrate;
- structuring the layer of high acoustic impedance to form a structured layer;
- depositing an uppermost mirror layer with a low acoustic impedance on the structured layer;
- thinning and planarizing an upper surface of the uppermost mirror layer to form a planar surface;
- forming a lower electrode on the planar surface;
- forming a structured piezoelectric layer on the lower electrode;
- and
- then forming an upper electrode on the structured piezoelectric layer.
6 more elements
Dependencies are inferred from the claim text.