Surface acoustic wave device

• US 6,664,709 B2
• Filed: 07/30/2001
• Issued: 12/16/2003
• Est. Priority Date: 08/09/2000
• Status: Expired due to Fees

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Irie, Yuji
• Primary Examiner(s): BUDD, MARK OSBORNE
• Application Number:
  US09/917,993
• Publication Number:
  US 20020043892A1
• Time in Patent Office: 869 Days
• Field of Search: 310/313.R, 310/340, 310/344, 310/348
• US Class Current: 310/313.00R
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• 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 2924/16195 Flat cap [not enclosing an internal cavity]
• CPC Class Codes: H03H 9/1071 the enclosure being defined by a frame built on a substrate and a cap, the frame having no mechanical contact with the SAW device

Abstract

A metallized electrode is provided at a fixed location of the main body of a package such that the metallized electrode is located above signal electrodes and is not in contact with the signal electrodes and an insulating joining material. Also, the metallized electrode is made conductive to the grounding electrode.

Claims

1. A surface acoustic wave device comprising:

a surface acoustic wave element; and

a package containing the surface acoustic wave element, the package including a main body having an opening and a hollow space therein, a cover provided on the upper surface of the main body of the package and arranged to close the opening portion of the main body of the package, signal electrodes arranged to transmit a signal input from the outside of the package and a signal output from the surface acoustic wave element, and a grounding electrode for grounding an unwanted electromagnetic wave generated inside the package;

wherein

an insulating joining material is arranged to join the main body of the package and the cover, a metallized electrode which is located above the signal electrodes and is not in contact with the signal electrodes and is not in contact with the insulating joining material, the metallized electrode being provided at a fixed location of the main body of the package, and the metallized electrode is electrically connected to the grounding electrode.

2. The surface acoustic wave device according to claim 1, wherein the package is made of one of an insulating material and ceramics.

3. The surface acoustic wave device according to claim 1, wherein the main body of the package includes a substrate and at least one frame body provided on the periphery of the substrate.

4. The surface acoustic wave device according to claim 3, wherein the surface acoustic wave element is fixed substantially in the center of the substrate.

5. The surface acoustic wave device according to claim 1, wherein the surface acoustic wave element is electrically connected to the grounding electrode and the signal electrodes.

6. The surface acoustic wave device according to claim 3, wherein the grounding electrode is arranged so as to connect the vicinity of the middle point of each of a pair of two facing sides on the surface of the substrate on which the surface acoustic wave element is fixed.

7. The surface acoustic wave device according to claim 1, wherein the grounding electrode is in contact with the bottom surface of the surface acoustic wave element.

8. The surface acoustic wave device according to claim 3, wherein the grounding electrode is arranged so as to continuously extend over the outside surface and bottom surface of the substrate.

9. The surface acoustic wave device according to claim 1, wherein the surface acoustic wave element is grounded by the grounding electrode such that the grounding electrode absorbs an unwanted electromagnetic wave generated by the surface acoustic wave element.

10. The surface acoustic wave device according to claim 3, wherein the at least one frame body includes two layers defining an upper frame body and a lower frame body.

11. A surface acoustic wave device comprising:

a surface acoustic wave element; and

a package containing the surface acoustic wave element, the package made up of a main body of the package of an insulating material having a hollow apace therein, a cover of an insulating material provided on the upper surface of the main body of the package and for closing the opening portion of the main body of the package, signal electrodes for transmitting a signal input from the outside of the package and a signal output from the surface acoustic wave element, and a grounding electrode for grounding an unwanted electromagnetic wave generated inside the package;

wherein

the main body of the package and the cover are joined at bonding surfaces of the package and the cover by thermocompression bonding, a metallized electrode which is located above the signal electrodes and is not in contact with the signal electrodes and is not in contact with the bonding surfaces of the package and the cover, the metallized electrode being provided at a fixed location of the main body of the package, and the metallized electrode is electrically connected to the grounding electrode.

12. The surface acoustic wave device according to claim 11, wherein the package is made of one of an insulating material and ceramics.

13. The surface acoustic wave device according to claim 11, wherein the main body of the package includes a substrate and at least one frame body provided on the periphery of the substrate.

14. The surface acoustic wave device according to claim 13, wherein the surface acoustic wave element is fixed substantially In the center of the substrate.

15. The surface acoustic wave device according to claim 11, wherein the surface acoustic wave element is electrically connected to the grounding electrode and the signal electrodes.

16. The surface acoustic wave device according to claim 13, wherein the grounding electrode is arranged so as to connect the vicinity of the middle point of each of a pair of two facing sides on the surface of the substrate on which the surface acoustic wave element is fixed.

17. The surface acoustic wave device according to claim 11, wherein the grounding electrode is in contact with the bottom surface of the surface acoustic wave element.

18. The surface acoustic wave device according to claim 13, wherein the grounding electrode is arranged so as to continuously extend over the outside surface and bottom surface of the substrate.

19. The surface acoustic wave device according to claim 11, wherein the surface acoustic wave element is grounded by the grounding electrode such that the grounding electrode absorbs an unwanted electromagnetic wave generated by the surface acoustic wave element.

20. The surface acoustic wave device according to claim 13, wherein the at least one frame body includes two layers defining an upper frame body and a lower frame body.