Crystal oscillator

• US 6,229,404 B1
• Filed: 08/31/1999
• Issued: 05/08/2001
• Est. Priority Date: 08/31/1998
• Status: Active Grant

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Corporation
• Inventors: Hatanaka, Hidefumi
• Primary Examiner(s): MIS, DAVID C
• Application Number:
  US09/387,148
• Time in Patent Office: 616 Days
• Field of Search: 331/66, 331/68, 331/108 D, 331/158, 331/175, 331/176, 310/315, 310/318, 310/340, 310/348, 257/469, 257/698, 257/700, 257/704, 257/723, 257/724, 361/728, 361/730, 361/753, 361/820
• US Class Current: 331/68
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• 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: H03B 5/04 Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature
• CPC Class Codes: H03B 5/32 being a piezoelectric resonator selection of piezoelectric material H10N30/00
• CPC Class Codes: H03H 9/08 Holders with means for regulating temperature
• CPC Class Codes: H05K 1/0243 Printed circuits associated with mounted high frequency components
• CPC Class Codes: H05K 2201/09181 Notches in edge pads
• CPC Class Codes: H05K 2201/09381 Shape of non-curved single flat metallic pad, land or exposed part thereof; Shape of electrode of leadless component
• CPC Class Codes: H05K 2201/10075 Non-printed oscillator
• CPC Class Codes: H05K 2201/10727 Leadless chip carrier [LCC], e.g. chip-modules for cards

Abstract

A crystal oscillator in which IC control terminal electrodes for writing temperature compensation data in an IC chip are formed on side surfaces of a main body while being distanced from the top and bottom surfaces of the main body. The IC control terminal electrodes will not be short-circuited with a conductive pattern for sealing the crystal oscillating element on the top surface, and the IC chip will not be destroyed by a welding current which flows when a metal cover is mounted on the top surface. The IC control terminal electrodes will not be short-circuited with other wiring conductors during the soldering to bond the crystal oscillator to a printed circuit board. The compensation data or other data written in the IC chip can be stably maintained, thereby securing a stable operation.

Claims

1. A crystal oscillator comprising:

an insulating main body having a top surface, a bottom surface, and a side surface, the insulating main body being formed with;

an upper space in an upper portion thereof, a first inner wall defining the upper space, the first inner wall provided with first electrode pads; and

a lower space in a lower portion thereof, a second inner wall defining the lower space, the second inner wall provided with second electrode pads;

a crystal oscillating element disposed in the upper space, electrically connected with the first electrode pads;

an IC chip disposed in the lower space, electrically connected with the second electrode pads for compensating the temperature-frequency variation characteristic of the crystal oscillating element;

IC control terminal electrodes provided on a side of the insulating main body, both upper and lower ends of the IC control terminal electrodes spaced apart from the top and bottom surfaces of the insulating main body electrically connectable with the second electrode pads;

external terminal electrodes disposed on the bottom surface of the insulating main body, connectable with a wiring conductor of a printed circuit;

a cover provided on the top surface of the insulating main body for hermetically sealing the upper space; and

a conductive path disposed within the main body for connecting the first electrode pads with the second electrode pads, the conductive path including a first via hole connected with the first electrode pads and extending in a depth direction along a first line, a second via hole conductor connected with the second electrode pads and extending in a depth direction along a second line offset from the first line, and an internal wiring conductor extending along a width of the main body connecting the first via hole conductor and the second via hole conductor.

2. A crystal oscillator according to claim 1, wherein the insulating main body is formed with recesses in the side thereof, and the IC control terminal electrodes are disposed on an inner wall of each recess.

3. A crystal oscillator according to claim 1, wherein the main body is formed of a plurality of insulating layers stacked one top of another, and is provided with an internal wiring conductor between the insulating layers and a lower wiring conductor on a ceiling surf ace of the lower space, and the second electrode pads connected with the IC chip and the IC control terminal electrodes are electrically connected by the internal wiring conductor and the lower wiring conductor.

4. A crystal oscillator according to claim 3, wherein the main body is further provided with viahole conductors extending in a thickness direction of the insulating layers, and the first electrode pads connected with the oscillating element and second electrodes connected with the IC chip are electrically connected by the viahole conductors and the internal wiring conductor.

5. A crystal oscillator according to claim 1, wherein the external terminal electrodes are formed at four corners of the bottom surface of the main body.

6. A method for manufacturing a crystal oscillator, comprising the steps of:

preparing a main body including an upper space portion having oscillating element electrode pads, a lower space portion having IC electrode pads, and conductors for connecting the oscillating element electrode pads and the IC electrode pads, said conductors comprising a first via hole connected with the oscillating element electrode pads and extending in a depth direction along a first line, a second via hole conductor connected with the IC electrode pads and extending in a depth direction along a second line offset from the first line, and an internal wiring conductor extending along a width of the main body connecting the first via hole conductor and the second via hole conductor, and IC terminal electrodes on a side thereof, and external terminal electrodes on a bottom thereof;

electrically connecting a crystal oscillating element with the oscillating element electrode pads via conductive adhesive;

measuring an oscillating frequency variation characteristic of the crystal oscillating element for frequency adjustment;

hermetically sealing the upper space portion in which the crystal oscillating element is mounted;

electrically connecting an IC chip with the IC electrode pads; and

writing the IC chip temperature compensation data for flattening the temperature-frequency variation characteristic of the crystal oscillating element via the IC control terminal electrodes.

7. A method according to claim 6, further comprising, before the step of writing the temperature compensation data, the step of filling resin in the lower space portion to protect the IC chip.

8. A method according to claim 6, further comprising, before the step of connecting the IC chip with the IC electrode pads, the step of cleaning the IC electrode pads.

9. A method according to claim 6, where the temperature compensation data is operable to define a function which flattens a temperature-frequency variation characteristic obtained based on frequency measurements within a predetermined temperature range.

10. A method for manufacturing a crystal oscillator, comprising the steps of:

preparing a first unit and a second unit, the first unit including a first space portion in an upper portion thereof, the first space portion having oscillating element electrode pads, and connection electrodes on a bottom surface thereof, the connection electrodes having an electrical connection with the oscillating element electrode pads, said electrical connection comprising a first via hole connected with the oscillating element electrode pads and extending in a depth direction along a first line, a second via hole conductor connected with the connection electrodes and extending in a depth direction along a second line offset from the first line, and an internal wiring conductor extending along a width direction connecting the first via hole conductor and the second via hole conductor,

the second unit including a second space portion in an upper portion thereof, the second space portion having IC electrode pads, and connection electrodes around an opening of the second space portion on a opt surface thereof and IC control terminal electrodes on a side thereof;

electrically connecting a crystal oscillating element with the oscillating element electrode pads via conductive adhesive;

measuring an oscillating frequency variation characteristic of the crystal oscillating element for frequency adjustment;

hermetically sealing the first space portion of the first space portion;

electrically connecting an IC chip with the IC electrode pads;

placing the first unit on the top of the second unit in such a manner that the first unit covers the second space portion of the second unit, and the connection electrodes of the first unit electrically join with the connection electrodes of the second unit; and

writing the IC chip temperature compensation data for flattening the temperature-frequency variation characteristic of the crystal oscillating element via the IC control terminal electrodes.

11. A method according to claim 10, further comprising, before the step of writing the temperature compensation data, the step of filling resin in the lower space portion to protect the IC chip.

12. A method according to claim 10, further comprising, before the step of connecting the IC chip with the IC electrode pads, the step of cleaning the IC electrode pads.

13. A method according to claim 10, where the temperature compensation data is operable to define a function which flattens a temperature-frequency variation characteristic obtained based on frequency measurements within a predetermined temperature range.