Method for manufacturing BAW resonators on a semiconductor wafer
First Claim
1. A method, comprising:
- forming a Bragg mirror on a substrate, the forming of the Bragg mirror including;
forming a first conductive layer having a temperature coefficient of acoustic velocity of a first sign;
forming a compensation layer on the first conductive layer, the compensation layer having a temperature coefficient of acoustic velocity of a second sign that is opposite to that of the first sign; and
decreasing thickness inequalities of the compensation layer at least until the compensation layer has a thickness variation less than 2%; and
forming a piezoelectric resonator on the compensation layer, the forming of the piezoelectric resonator including;
forming a first electrode on the compensation layer;
forming a piezoelectric layer on the first electrode; and
forming a second electrode on the piezoelectric layer.
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Abstract
A method for manufacturing a wafer on which are formed resonators, each resonator including, above a semiconductor substrate, a stack of layers including, in the following order from the substrate surface: a Bragg mirror; a compensation layer made of a material having a temperature coefficient of the acoustic velocity of a sign opposite to that of all the other stack layers; and a piezoelectric resonator, the method including the successive steps of: a) depositing the compensation layer; and b) decreasing thickness inequalities of the compensation layer due to the deposition method, so that this layer has a same thickness to within better than 2%, and preferably to within better than 1%, at the level of each resonator.
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Citations
15 Claims
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1. A method, comprising:
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forming a Bragg mirror on a substrate, the forming of the Bragg mirror including; forming a first conductive layer having a temperature coefficient of acoustic velocity of a first sign; forming a compensation layer on the first conductive layer, the compensation layer having a temperature coefficient of acoustic velocity of a second sign that is opposite to that of the first sign; and decreasing thickness inequalities of the compensation layer at least until the compensation layer has a thickness variation less than 2%; and forming a piezoelectric resonator on the compensation layer, the forming of the piezoelectric resonator including; forming a first electrode on the compensation layer; forming a piezoelectric layer on the first electrode; and forming a second electrode on the piezoelectric layer. - View Dependent Claims (2)
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3. A method, comprising:
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forming a stack of layers on a semiconductor substrate, the forming of the stack of layers including; forming a Bragg mirror on the substrate, the Bragg mirror including; a first conductive layer on the substrate; a first dielectric layer on the first conductive layer; a second conductive layer on the first dielectric layer; and a second dielectric layer on the second conductive layer, the first and second conductive layers having a temperature coefficient of acoustic velocity (TCV) of a first sign; depositing a compensation layer on the second dielectric layer of the Bragg mirror, the compensation layer having a TCV of a second sign that is opposite to that of the first sign; and decreasing thickness inequalities of the compensation layer at least until the compensation layer has a thickness variation less than 2%; and forming a piezoelectric resonator on the compensation layer, the forming of the piezoelectric resonator including; forming a first electrode on the compensation layer; forming a layer of a piezoelectric material on the lower electrode; and forming a second electrode on the layer of the piezoelectric material. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method, comprising:
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forming a Bragg mirror, including; forming a first dielectric layer on a substrate; forming a first conductive layer on the first dielectric layer; forming a second dielectric layer on the first conductive layer; and forming a second conductive layer on the second dielectric layer; forming a temperature compensation layer on the second conductive layer of the Bragg mirror; and decreasing thickness inequalities of the temperature compensation aver at east until the compensation layer has a thickness variation less than 2%; and forming a piezoelectric resonator on the temperature compensation layer, the forming the piezoelectric resonator including; forming a first electrode on the temperature compensation layer; forming a piezoelectric material layer on the first electrode; and forming a second electrode on the piezoelectric material layer. - View Dependent Claims (14, 15)
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Specification