Piezoelectric filter, duplexer, composite piezoelectric resonator, communication device and method for adjusting frequency of piezoelectric filter
First Claim
1. A piezoelectric filter comprising:
- a plurality of piezoelectric resonators including a substrate and a vibration portion provided on the substrate, the vibration portion having a structure in which top and bottom surfaces of a thin film portion including at least one piezoelectric thin film are sandwiched between at least a pair of an upper electrode and a lower electrode facing each other; and
an additional film provided on the upper electrode of at least one of the plurality of piezoelectric resonators;
wherein the additional film has susceptibility to physical etching that is lower than that of materials used for the upper electrodes of the others of the plurality of piezoelectric resonators.
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Accused Products
Abstract
A piezoelectric filter and other electronic components are constructed such that the accuracy of frequency adjustment can be increased and an improvement in efficiency of the adjustment operation can be achieved. The piezoelectric filter includes a plurality of piezoelectric resonators including a substrate and a vibration portion provided on the substrate, the vibration portion having a structure in which the top and bottom surfaces of a thin film portion including at least one piezoelectric thin film are sandwiched between at least a pair of an upper electrode and a lower electrode facing each other, wherein the upper electrode of a predetermined piezoelectric resonator is made of a material having susceptibility to etching that is different from that of the upper electrode of the other piezoelectric resonator.
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Citations
28 Claims
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1. A piezoelectric filter comprising:
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a plurality of piezoelectric resonators including a substrate and a vibration portion provided on the substrate, the vibration portion having a structure in which top and bottom surfaces of a thin film portion including at least one piezoelectric thin film are sandwiched between at least a pair of an upper electrode and a lower electrode facing each other; and
an additional film provided on the upper electrode of at least one of the plurality of piezoelectric resonators;
whereinthe additional film has susceptibility to physical etching that is lower than that of materials used for the upper electrodes of the others of the plurality of piezoelectric resonators. - View Dependent Claims (2, 4, 5, 12, 13, 17, 26)
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3. A piezoelectric filter comprising:
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a plurality of piezoelectric resonators including a substrate and a vibration portion provided on the substrate, the vibration portion having a structure in which top and bottom surfaces of a thin film portion including at least one piezoelectric thin film are sandwiched between at least a pair of an upper electrode and a lower electrode facing each other;
whereinthe vibration portions of the plurality of piezoelectric resonators are covered with a protective film, and an additional electrode is provided on the upper electrode of at least one of the plurality of piezoelectric resonators with the protective film being located therebetween; and
the protective film has susceptibility to physical etching that is lower than that of the additional electrode.
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6. A piezoelectric filter comprising:
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a plurality of piezoelectric resonators including a piezoelectric substrate and a vibration portion having a structure in which the piezoelectric substrate is sandwiched between at least a pair of an upper electrode and a lower electrode facing each other;
whereinthe upper electrode of at least one of the plurality of piezoelectric resonators is made of a material having susceptibility to etching that is different from that of the upper electrodes of the other piezoelectric resonators. - View Dependent Claims (8, 9, 10, 11)
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7. A piezoelectric filter comprising:
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a plurality of piezoelectric resonators including a piezoelectric substrate and a vibration portion having a structure in which the piezoelectric substrate is sandwiched between at least a pair of an upper electrode and a lower electrode facing each other;
whereinan additional film is provided on the upper electrode of at least one of the plurality of piezoelectric resonators, and the additional film has susceptibility to etching that is different from that of the material for the upper electrode.
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14. A composite piezoelectric resonator comprising:
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a plurality of piezoelectric resonators including a substrate and a vibration portion provided on the substrate, the vibration portion having a structure in which top and bottom surfaces of a thin film portion including at least one piezoelectric thin film are sandwiched between at least a pair of an upper electrode and a lower electrode facing each other; and
an additional film provided on the upper electrode of at least one of the plurality of piezoelectric resonators;
whereinthe additional film has susceptibility to physical etching that is lower than that of materials used for the upper electrodes of the others of the plurality of piezoelectric resonators. - View Dependent Claims (15, 16, 27, 28)
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18. A method for adjusting the frequency of a piezoelectric filter comprising the steps of:
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providing a piezoelectric filter including a plurality of piezoelectric resonators including a substrate and a vibration portion provided on the substrate, the vibration portion having a structure in which top and bottom surfaces of a thin film portion including at least one piezoelectric thin film are sandwiched between at least a pair of an upper electrode and a lower electrode facing each other and an additional film is provided on the upper electrode of at least one of the plurality of piezoelectric resonators, and the additional film has susceptibility to physical etching that is lower than that of materials used for the upper electrodes of the others of the plurality of piezoelectric resonators; and
adjusting the frequency of the at least one of the plurality of piezoelectric resonators by etching the upper electrode of the at least one of the plurality of piezoelectric resonators. - View Dependent Claims (20)
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19. A method for adjusting the frequency of a piezoelectric filter comprising the steps of:
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providing a piezoelectric filter including a plurality of piezoelectric resonators including a substrate and a vibration portion provided on the substrate, the vibration portion having a structure in which top and bottom surfaces of a thin film portion including at least one piezoelectric thin film are sandwiched between at least a pair of an upper electrode and a lower electrode facing each other, the vibration portions of the plurality of piezoelectric resonators are covered with a protective film, and an additional electrode provided on the upper electrode of at least one of the plurality of piezoelectric resonators with the protective film being located therebetween, wherein the protective film has susceptibility to physical etching that is lower than that of the additional electrode; and
adjusting the frequency of the at least one of the plurality of piezoelectric resonators by etching the additional electrode.
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21. A method for adjusting the frequency of a piezoelectric filter comprising the steps of:
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providing a piezoelectric filter including a plurality of piezoelectric resonators including a piezoelectric substrate and a vibration portion having a structure in which the piezoelectric substrate is sandwiched between at least a pair of an upper electrode and a lower electrode facing each other, the upper electrode of at least one of the plurality of piezoelectric resonators is made of a material having susceptibility to etching that is different from that of the upper electrodes of the other piezoelectric resonators; and
adjusting the frequency of the at least one of the plurality of piezoelectric resonators by etching the upper electrode of the at least one of the plurality of piezoelectric resonators. - View Dependent Claims (23, 24, 25)
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22. A method for adjusting the frequency of a piezoelectric filter comprising the steps of:
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providing a piezoelectric filter including a plurality of piezoelectric resonators including a piezoelectric substrate and a vibration portion having a structure in which the piezoelectric substrate is sandwiched between at least a pair of an upper electrode and a lower electrode facing each other, an additional film provided on the upper electrode of at least one of the plurality of piezoelectric resonators, and the additional film has susceptibility to etching that is different from that of the material for the upper electrode; and
adjusting the frequency of the at least one of the plurality of piezoelectric resonators by etching the additional film.
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Specification