Angular velocity sensor, related method for manufacturing the sensor, and piezoelectric vibrator element used in this sensor

• US 6,360,600 B1
• Filed: 09/09/1999
• Issued: 03/26/2002
• Est. Priority Date: 04/14/1997
• Status: Expired due to Term

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kuroki, Hisao, Kamimura, Rikiya
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US09/392,635
• Time in Patent Office: 929 Days
• Field of Search: 735/041.6, 735/041.2, 735/041.3, 735/041.4, 735/041.5, 735/143.4, 310/361, 310/366, 310/370, 310/364, 310/363, 310/358
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5607 using vibrating tuning forks double-ended tuning forks using planar vibrating masses suspended at opposite ends G01C19/5719
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/4809 Loop shape
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/4823 connecting the wire to a pin of the item
• CPC Class Codes: H01L 2224/48472 the other connecting portion not on the bonding area also being a wedge bond, i.e. wedge-to-wedge
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/78313 Wedge
• CPC Class Codes: H01L 2224/78318 inside the capillary
• CPC Class Codes: H01L 2224/78901 using a computer, e.g. fully- or semi-automatic bonding
• CPC Class Codes: H01L 2224/85181 connecting first on the semiconductor or solid-state body, i.e. on-chip, regular stitch
• CPC Class Codes: H01L 2224/85205 Ultrasonic bonding
• CPC Class Codes: H01L 2224/92247 the second connecting process involving a wire connector
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/78 Apparatus for connecting with wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/01039 : Yttrium [Y]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/3011 : Impedance

Abstract

Drive electrodes and sensing electrodes are formed on a front face of a piezoelectric body of a vibrator. A first reference electrode is formed on a rear face. Second reference electrodes are formed on side faces of arm bars of the vibrator at a position corresponding to the sensing electrodes. The second reference electrodes are connected to the first reference electrode formed on said rear face.

Claims

1. A piezoelectric vibrator element comprising:

a piezoelectric vibrator member,

at least one electrode formed on an outer surface of said vibrator member so as to have an outer surface to which ultrasonic wire bonding is applied, and

at least one lead wire, extending in the air from said electrode, with one end bonded to said outer surface of said electrode by ultrasonic wire bonding,

wherein said lead wire has a diameter less than or equal to 50 μ

m and contains aluminum as a chief component, and

said electrode is a silver thick film containing palladium in an amount greater than or equal to 5% by weight.

2. The piezoelectric vibrator element in accordance with claim 1, wherein said electrode has a film thickness in a range of 10 μ

m to 40 μ

m.

3. An angular velocity sensor with a vibrator, a base plate, and a supporter interposed between said vibrator and said base plate,

said vibrator comprising a piezoelectric body having at least one polygonal arm bar and electrodes formed on said piezoelectric body, said electrodes including at lease one drive electrode and at least one sensing electrode formed on a first face of said piezoelectric body and a common electrode formed on an opposing second face of said piezoelectric body, said first face and said second face extending in a Z-axis direction parallel to a longitudinal direction of said vibrator, said common electrode being integrally connected to at least one outlet electrode formed on said first face,

said base plate opposed to said second face,

said supporter supporting said vibrator on said base plate,

said arm bar vibrating in a Y-axis direction parallel to said first and second faces and normal to said Z-axis direction when an alternating voltage is applied between said drive electrode and said common electrode, and

said sensing electrode producing a signal representing a vibration of said arm bar caused in an X-axis direction due to an angular velocity of said vibrator appearing about the Z-axis,

wherein at least one lead wire extends in the air from one of the electrodes formed on said first face, with one end bonded to one of the electrodes formed on said first face, and said lead wire contains aluminum as a chief component and is bonded to an outer surface of said one of the electrode formed on said first face by ultrasonic wire bonding, and

said one of the electrodes formed on said first face and bonded to said lead wire has a double-layer construction comprising a first-layer electrode formed on said first surface and a second-layer electrode formed on the first-layer electrode, and said second-layer electrode is a silver thick film containing palladium in an amount greater than or equal to 5% of weight.

4. The angular velocity sensor in accordance with claim 3, wherein said second-layer electrode contains palladium by an amount equal to or smaller than 50% as a weight percentage relative to the total amount of said silver thick film contain palladium.

5. A piezoelectric vibrator comprising:

a piezoelectric vibrator member,

at least one electrode formed on an outer surface of said vibrator member,

at least one terminal provided for signal transmission, and

at least one lead wire, with a diameter less than or equal to 50 μ

m, straddling between said electrode and said terminal, wherein

said lead wire contains aluminum as a chief component and is bonded to an outer surface of said electrode and said terminal by ultrasonic wire bonding, and

said electrode is a silver thick film containing palladium in an amount greater than or equal to 5% by weight.

6. A piezoelectric vibrator element comprising:

a piezoelectric vibrator member,

at least one electrode formed on an outer surface of said vibrator member, and

at least one lead wire bonded to said electrode,

wherein said lead wire contains aluminum as a chief component, and

said electrode comprises at least one first-layer electrode formed on a surface of said vibrator member and a second-layer electrode formed directly on said first-layer electrode so as to constitute a double-layer construction; and

wherein said first-layer electrode contains 1 to 15% by weight glass or inorganic oxide and said second-layer electrode contains 0 to 1% by weight glass or inorganic oxide.

7. The piezoelectric vibrator element in accordance with claim 6, wherein said second-layer electrode contains 5 to 50% by weight palladium.

8. The piezoelectric vibrator element in accordance with claim 6, wherein said lead wire is bonded to said electrode by ultrasonic wire bonding.