AU739653B2

AU739653B2 - Integrated electronic structure

Info

Publication number: AU739653B2
Application number: AU51261/98A
Authority: AU
Inventors: Anthony Lonsdale; Bryan Lonsdale
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-11-13
Filing date: 1997-11-13
Publication date: 2001-10-18
Anticipated expiration: 2017-11-13
Also published as: AU5126198A

Description

P:~p sb 51261-98-.d.-26i07iO -1- INTEGRATED ELECTRONIC

STRUCTURE

Technical Field This invention relates to an integrated electronic structure using piezoelectric material and bonded interdigital arrays. More particularly the invention is directed towards utilising different properties of the piezoelectric material to perform different functions within the same structure.

Background Art The process of using the piezoelectric properties of a material in combination with bonded electrodes in the form of interdigital arrays for the control or processing of electrical signals is known. Surface acoustic wave devices such as resonators, delay lines, filters or convolvers are in widespread use throughout the world. The majority use quartz as the piezoelectric material, however other materials in use include directionally oriented .i S•zinc oxide and aluminium nitride. These devices are usually discrete devices in their own enclosure supported and connected to other components by a printed circuit board or wires.

oo 0: So The process of using the dielectric properties of a base material is also known. Capacitors, S 20 inductors or high frequency transmission lines are often etched into printed circuit boards along with other conductive tracks. The dielectric properties of the base integrated electronic structure material of the printed circuit board is utilised in this case.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common :i general knowledge in Australia.

An object of this invention is to address the case where a number of electrical elements are needed in a circuit, some items requiring piezoelectric properties to function and some elements requiring dielectric properties to function, or to at least provide a useful T<a\lternative to the prior art.

P:operssbl51261 -98res.doc-26/07/I1 -2- Summary of the Invention The present invention provides an electronic structure comprising an electrically conductive base member having a layer of piezoelectric material bonded thereon, and the layer of piezoelectric material having both piezoelectric properties and dielectric properties; wherein at least a first interdigital array and a second interdigital array are bonded to the layer of piezoelectric material on a surface of the layer of piezoelectric material opposite from the base member and, during operation of the electronic structure, the first interdigital array utilises the piezoelectric properties of the layer of piezoelectric material and the second interdigital array utilises the dielectric properties of the layer of piezoelectric material, and the first interdigital array and the second interdigital array form at least a portion of an oscillator; and the second interdigital array partially forms at least one directional coupler.

15 The present invention further provides an electronic structure comprising an electrically .conductive base member having a layer of piezoelectric material bonded thereon, and the layer of piezoelectric material having both piezoelectric properties and dielectric properties; wherein two first interdigital arrays and two second interdigital arrays are bonded to the layer of piezoelectric material on a surface of the layer of piezoelectric material opposite from the base member and, during operation of the electronic structure, the two first interdigital arrays utilise the piezoelectric properties of the layer of piezoelectric material and the two second interdigital arrays utilise the dielectric properties of the layer 'of piezoelectric material, and at least one of the two first interdigital arrays and at least one 25 of the two second interdigital arrays form at least a portion of an oscillator; and at least one of the two second interdigital arrays at least partially forms a directional coupler.

Preferably said first interdigital array forms part of at least one oscillator, such as a surface acoustic wave resonator, a shallow bulk acoustic wave ('SBAW') resonator or the P:.opcrsIb\51261-98rdoc-26 07/01 -2A- Preferably said second interdigital array forms part of at least one directional coupler such as a Lange coupler.

Brief Description of the Drawings Figure 1 shows a plan view of one embodiment of the invention; Figure 2 shows a section through Figure 1 indicating the layers and connections.

Mode of Carrying out Invention Figure 1 shows a plan view of one embodiment of the invention. Electrically conductive base member 2 has a layer 15 of piezoelectric material bonded thereon. Silicon chip electronic circuit 1 is attached to the centre of base member 2. SAW resonators 5 and 6 are formed on the surface of piezoelectric 15 by conductive interdigital arrays being vapour 15 deposited on to this surface. SAW resonators 5 and 6 utilise the piezoelectric properties of the layer.

*o Lange couplers 2 and 3 are also formed on the surface of piezoelectric layer 15 by additional conductive interdigital arrays vapour deposited thereto. Lange couplers 2 and 3, although formed on the surface of a piezoelectric material, use only the dielectric, and not I the piezoelectric, properties of the layer material. SAW resonators 5 and 6, and Lange couplers 2 and 3, are connected to silicon chip electronic circuit 1 by wire bonding or other suitable methods to create an operational circuit.

*oo Figure 2 is a cross section through the integrated electronic structure 15 showing electrically conductive base element 2 through which connection pins 12 and 13 are passed. The pins are insulated from the base element by a sealing and insulating material such as glass or glass like material with a suitable co-efficient of thermal expansion element 14. Piezoelectric layer 15 is bonded to base element 2, with the connection pins passing through the layer. Interdigital array 16 is vapour deposited on to piezoelectric layer 15 and makes electrical contact with connection pins 12 and 13.

The above described embodiment of an integrated electronic structure can be used as a component part in apparatus and method described in our two PCT Applications entitled 'Apparatus for Measuring Impedance of a Resonant Structure' and 'Apparatus for Tracking Resonant Frequency' both filed on the same date as the present application.

It will be recognised by persons skilled in the art that numerous variations and modifications may be made to the invention without departing from the spirit and scope of the invention.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variitionssuch as '"comprieS'" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

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Claims

1. An electronic structure comprising an electrically conductive base member having a layer of piezoelectric material bonded thereon, and the layer of piezoelectric material having both piezoelectric properties and dielectric properties; wherein at least a first interdigital array and a second interdigital array are bonded to the layer of piezoelectric material on a surface of the layer of piezoelectric material opposite from the base member and, during operation of the electronic structure, the first interdigital array utilises the piezoelectric properties of the layer of piezoelectric material and the second interdigital array utilises the dielectric properties of the layer of piezoelectric material, and the first interdigital array and the second interdigital array form at least a portion of an oscillator; and the second interdigital array partially forms at least one directional coupler.

2. The electronic structure according to claim 1, wherein one of an inductive element and a capacitative element is attached to the layer of piezoelectric.

3. The electronic structure according to claim 1, wherein the oscillator is one of a surface acoustic wave resonator and a shallow bulk acoustic wave resonator. i ne electronic structure according to claim 1, wherein the at least one directional 9 coupler is a Lange coupler. 25 and a capacitative element is attached to the layer of piezoelectric. 0o 00

6. The electronic structure according to claim 3, wherein one of an inductive element and a capacitative element is attached to the layer of piezoelectric material.

7. An electronic structure comprising an electrically conductive base member having layer of piezoelectric material bonded thereon, and the layer of piezoelectric material t P:\operssb\51261 -98r.doc26/07/01l having both piezoelectric properties and dielectric properties; wherein two first interdigital arrays and two second interdigital arrays are bonded to the layer of piezoelectric material on a surface of the layer of piezoelectric material opposite from the base member and, during operation of the electronic structure, the two first interdigital arrays utilise the piezoelectric properties of the layer of piezoelectric material and the two second interdigital arrays utilise the dielectric properties of the layer of piezoelectric material, and at least one of the two first interdigital arrays and at least one of the two second interdigital arrays form at least a portion of an oscillator; and at least one of the two second interdigital arrays at least partially forms a directional coupler.

8. The electronic structure according to claim 7, wherein the oscillator is one of a surface acoustic wave resonator and a shallow bulk acoustic wave resonator. S 15 9. An electronic structure substantially as hereinbefore described with reference to the accompanying drawings. by DAVIES COLLISON CAVE Patent Attorneys for the Applicant e DAltiJ LIis /tll uay ou July, 2UUI Anthony Lonsdale and Bryan Lonsdale by DAVIES COLLISON CAVE Patent Attorneys for the Applicant i