Arrangement of a piezoacoustic resonator on an acoustic mirror of a substrate, method for producing the arrangement and use of the arrangement
Inventors
Pitzer, Dana • Schreiter, Matthias
Assignees
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Publication Number
US-8536764-B2
Publication Date
2013-09-17
Expiration Date
Abstract
In an arrangement of at least one piezoacoustic resonator on a substrate surface, the resonator has an piezoelectric layer, an electrode and a further electrode arranged such that activation of the electrodes leads to a resonance oscillation, the substrate surface is formed by an acoustic mirror integrated in the substrate for acoustically insulating substrate and resonator, and with a resonance frequency evaluation device being connected to the electrodes by tracks being routed through a mirror opening. The acoustic mirror has a Bragg reflector having λ/4-thick layers of different acoustic impedance. The topmost layer is made of silicon dioxide acting as an insulation layer in the mirror opening for electrically insulating the conductor track and the electrically conductive Bragg reflector layers. The arrangement is used as a physical transducer of a device for detecting a substance of a fluid, in particular of a fluid in the form of a liquid (biosensor).
Core Innovation
The invention relates to an arrangement of at least one piezoacoustic resonator on a substrate surface of a substrate. The piezoacoustic resonator comprises at least one piezoelectric layer, an electrode and at least one further electrode configured so that an electrical activation of the electrodes leads to resonance oscillation at a resonance frequency. The substrate surface is formed by an acoustic mirror integrated in the substrate for acoustically insulating the substrate and the resonator from each other.
An evaluation device integrated in the substrate determines the resonance frequency of the resonator. The evaluation device and at least one electrode are connected to each other in an electrically conductive manner by way of an electric conductor track on the acoustic mirror. The conductor track is routed through a mirror opening of the acoustic mirror, and a lateral edge of the mirror opening has an electrical opening insulation layer comprising opening insulation material on which the conductor track is applied.
A method for producing the arrangement is also described by providing a substrate with an acoustic mirror that forms a substrate surface and includes a mirror opening for connecting a readout circuit of an evaluation device integrated in the substrate in an electrically conductive manner. The method includes arranging an electric conductor track on the mirror and in the mirror opening so that the readout circuit and the conductor track are connected in an electrically conductive manner, and providing the lateral edge of the mirror opening with an electrical opening insulation layer comprising opening insulation material on which the conductor track is applied.
Claims Coverage
The document includes two independent claims. Across these independent claims, the inventive features focus on an acoustically insulating substrate surface formed by an integrated acoustic mirror, conductive connection of an integrated evaluation/readout device to resonator electrodes via a conductor track routed through a mirror opening with an opening insulation layer at the lateral edge, and a production method that arranges the conductor track and applies the opening insulation layer on the mirror opening edge.
Piezoacoustic resonator arrangement with integrated acoustic insulation
An arrangement of at least one piezoacoustic resonator on a substrate surface, where the resonator has at least one piezoelectric layer, an electrode and at least one further electrode arranged so that electrical activation leads to resonance oscillation at a resonance frequency, and where the substrate surface is formed by an acoustic mirror integrated in the substrate for acoustically insulating the substrate and the resonator from each other.
Electrically conductive connection through a mirror opening with opening insulation layer
An evaluation device integrated in the substrate determines the resonance frequency, where the evaluation device and at least one of the electrodes are connected in an electrically conductive manner by way of an electric conductor track on the acoustic mirror, the conductor track is routed through a mirror opening of the acoustic mirror, and a lateral edge of the mirror opening has an electrical opening insulation layer comprising opening insulation material on which the conductor track is applied.
Method for producing the acoustically mirrored resonator arrangement with insulated mirror opening edge
A method for producing an arrangement of at least one piezoacoustic resonator on a substrate surface, including providing a substrate with an acoustic mirror forming the substrate surface and having a mirror opening for electrically conductive connection of a readout circuit of an evaluation device integrated in the substrate, arranging an electric conductor track on the mirror and in the mirror opening so the readout circuit and conductor track are connected electrically conductively, and providing a lateral edge of the mirror opening with an electrical opening insulation layer comprising opening insulation material on which the conductor track is applied.
Overall, the claim coverage centers on pairing a resonator/evaluation structure with an integrated acoustic mirror that provides acoustic insulation, while ensuring electrical conductivity between the evaluation/readout circuit and resonator electrodes via a conductor track routed through a mirror opening. The lateral edge insulation layer is a defined structural feature, and the method claim corresponds to producing the arrangement with the conductor track arrangement and insulated mirror-opening edge.
Stated Advantages
Space-saving reliable electrical contact.
Reliable electrical insulation of the conductor track from metallic mirror layers.
Acoustic-mirror λ/4 insulation thickness enabling capacitive decoupling and efficient insulation.
Low manufacturing cost (no extra insulation layers).
Partial planarization for photolithography.
Documented Applications
Biosensing by resonance frequency evaluation using longitudinal and shear thickness-mode excitation to detect a substance in a fluid via resonance frequency shift due to fluid substance mass loading.
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