Surface acoustic wave device comprising first and second chips face down bonded to a common package ground

• US 6,339,365 B1
• Filed: 12/28/1999
• Issued: 01/15/2002
• Est. Priority Date: 12/29/1998
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Kuroda, Yasushi, Kawase, Minoru
• Primary Examiner(s): Pascal, Robert
• Assistant Examiner(s): Summons, Barbara
• Application Number:
  US09/472,813
• Time in Patent Office: 749 Days
• Field of Search: 333/133, 333/193-196, 310/313.R, 310/344, 310/346-349
• US Class Current: 333/193
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2924/16195 Flat cap [not enclosing an internal cavity]
• CPC Class Codes: H03H 2009/0019 Surface acoustic wave multichip
• CPC Class Codes: H03H 9/059 consisting of mounting pads or bumps
• 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

An object of the present invention is to provide a filter that enables to manufacture in a multi-chip package with ease and that is of small size and multi-function or multi-mode. In a constitution of the present invention, a filter comprises a package comprising a base on one main surface thereof a conductor is formed, and a plurality of surface acoustic wave chips comprising a plurality of interdigital transducers formed on one main surface of a piezoelectric substrate, signal terminals disposed on facing sides on the piezoelectric substrate, and ground terminals disposed on the piezoelectric substrate. Here, the plurality of surface acoustic wave chips, at the signal terminals and the ground terminals, is bonded to the conductor in a face down way.

Claims

1. A surface acoustic wave device, comprising:

a package comprising a base on a first main surface thereof on which a plurality of signal conductors and a ground conductor are formed;

a first surface acoustic wave chip disposed over the base in a face down way, comprising a plurality of first interdigital transducers formed on the first main surface of a first piezoelectric substrate, first signal terminals disposed on the first main surface, and a first ground terminal disposed on the first main surface;

a second surface acoustic wave chip disposed over the base in a face down way, including a plurality of second interdigital transducers disposed on a second main surface of a second piezoelectric substrate, second signal terminals disposed on the second main surface, and a second ground terminal disposed on the second piezoelectric substrate; and

wherein each of the first and the second signal terminals are bonded to each of the plurality of signal conductors through a bump, both of the first and the second ground terminals are bonded to the ground conductor in common through bumps, a plurality of portions of the ground conductor are projected between adjacent signal conductors, and each of the portions of the ground conductor is respectively connected to wiring.

2. The surface acoustic wave device as set forth in claim 1,

wherein the first and the second surface acoustic wave chips are disposed, so that adjacent sides of the first and the second surface acoustic wave chips on which the first and the second signal terminals are not disposed are approximately parallel to each other;

wherein the first and the second signal terminals are disposed, so that rows of the first and the second signal terminals disposed on each opposing side are approximately parallel to each other.

3. The surface acoustic wave device as set forth in claim 2,

wherein all the first and the second interdigital transducers are facing the ground conductor.

4. The surface acoustic wave device as set forth in claim 1,

wherein the plurality of signal conductors, except for one side thereof, are surrounded by a portion of the ground conductor.

5. The surface acoustic wave device as set forth in claim 1,

wherein at least a portion of the ground conductor is formed in a cross.

6. The surface acoustic wave device as set forth in claim 1,

wherein each of the first surface acoustic wave chip and the second surface acoustic wave chip has a plurality of ground terminals, and all the ground terminals are connected to the ground conductor in common through bumps.

7. The surface acoustic wave device as set forth in claim 1,

wherein at least one chip of the first and the second surface acoustic wave chips includes a plurality of surface acoustic wave elements connected in a cascade connection.

8. The surface acoustic wave device as set forth in claim 1,

wherein at least one chip of the first and the second surface acoustic wave chips comprises a longitudinal mode-coupled surface acoustic wave element.

9. The surface acoustic wave device as set forth in claim 8:

wherein a longitudinal mode-coupled surface acoustic wave element comprises a plurality of interdigital tranducers of the same shape.

10. The surface acoustic wave device as set forth in claim 1, further comprising:

an external selection circuit configured to supply input signals selectively to one of the first and the second surface acoustic wave chips.

11. The surface acoustic wave device as set forth in claim 1,

wherein propagation characteristics of the first piezoelectric substrate is different from that of the second piezoelectric substrate.

12. The surface acoustic wave device as set forth in claim 1,

wherein a thickness of electrode fingers constituting the first interdigital transducers is different from that of electrode fingers constituting the second interdigital transducers.

13. The surface acoustic wave device as set forth in claim 1,

wherein electrode finger material constituting the first interdigital transducers is different from that constituting the second interdigital transducers.

14. The surface acoustic wave device as set forth in claim 1,

wherein a duty ratio of electrode fingers constituting the first interdigital transducers is different from that of electrode fingers constituting the second interdigital transducers.

15. The surface acoustic wave device as set forth in claim 1,

wherein an external dimension of the first surface acoustic wave chips is different from that of the second surface acoustic wave chip.

16. The surface acoustic wave device as set forth in claim 15,

wherein a thickness of the first piezoelectric substrate is different from that of the second piezoelectric substrate.

17. The surface acoustic wave device as set forth in claim 1,

wherein surface roughness of a rear surface of the first piezoelectric substrate is different from that of the second piezoelectric substrate.