Method for fabricating a resonator having an acoustic mirror
First Claim
1. A method for fabricating a Thin Film Bulk Acoustic Wave Resonator (FBAR), comprising the steps of:
- STEP A1;
forming a first layer on a substrate, the first layer being comprised of a polymer;
STEP A2;
forming a second, lower electrode layer on an upper surface of the first layer, wherein the first and second layers form an acoustic isolator and wherein STEP A1 includes forming the first layer so as to have a thickness which is an odd multiple of one-fourth of an acoustic wavelength, and wherein STEP A2 includes forming the second layer so as to have a thickness which is an odd multiple of one-fourth of the acoustic wavelength;
STEP B;
forming a piezoelectric layer on the acoustic isolator; and
STEP C;
forming an upper electrode layer on the piezoelectric layer.
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Accused Products
Abstract
A Thin Film Bulk Acoustic Wave Resonator (FBAR), comprising a top electrode layer, a substrate, an acoustic mirror that is formed atop the substrate, and a piezoelectric layer that is formed between the top electrode layer and the acoustic mirror. The acoustic mirror is comprised of a plurality of stacked layers. One of the stacked layers forms a bottom electrode layer. At least another one of the stacked layers comprises a polymer material. The piezoelectric produces vibrations in response to a voltage being applied between the top electrode and the bottom electrode. The acoustic mirror acoustically isolates these vibrations from the substrate. The polymer material is preferably an electronic grade polymer and has a capability of withstanding a deposition of the piezoelectric layer at an elevated temperature. The layers forming the acoustic mirror which do not comprise the polymer material comprise a high acoustic impedance material such as, by example, tungsten (W). The polymer material can be spun on the substrate during fabrication of the FBAR.
242 Citations
22 Claims
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1. A method for fabricating a Thin Film Bulk Acoustic Wave Resonator (FBAR), comprising the steps of:
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STEP A1;
forming a first layer on a substrate, the first layer being comprised of a polymer;STEP A2;
forming a second, lower electrode layer on an upper surface of the first layer, wherein the first and second layers form an acoustic isolator and wherein STEP A1 includes forming the first layer so as to have a thickness which is an odd multiple of one-fourth of an acoustic wavelength, and wherein STEP A2 includes forming the second layer so as to have a thickness which is an odd multiple of one-fourth of the acoustic wavelength;STEP B;
forming a piezoelectric layer on the acoustic isolator; andSTEP C;
forming an upper electrode layer on the piezoelectric layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for fabricating a Thin Film Bulk Acoustic Wave Resonator (FBAR), comprising the steps of:
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forming a multi-layered acoustic isolator on a surface of a substrate, wherein a first plurality of layers of the acoustic isolator are comprised of a polymer having a first acoustic impedance, wherein a second plurality of layers of the acoustic isolator have a second acoustic impedance, wherein individual ones of the first plurality of layers and individual ones of the second plurality of layers are alternately disposed within the acoustic isolator, wherein one of the first plurality of layers is disposed on the substrate, and wherein one of second plurality of layers forms a lower electrode layer and is disposed on one of the first plurality of layers; forming a piezoelectric layer on the acoustic isolator; and forming an upper electrode layer on the piezoelectric layer. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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Specification