ULTRASONIC TRANSDUCER STRUCTURE, ULTRASONIC TRANSDUCER, AND METHOD OF MANUFACTURING ULTRASONIC TRANSDUCER

• US 20130169110A1
• Filed: 09/14/2012
• Published: 07/04/2013
• Est. Priority Date: 12/28/2011
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: JEONG, Byung-gil, HONG, Seog-woo, KIM, Dong-kyun, SHIN, Hyung-jae, CHUNG, Seok-whan
• Granted Patent: US 9,120,127 B2
• Time in Patent Office: Days
• US Class Current: 310/314
• CPC Class Codes: B06B 1/0292 Electrostatic transducers, e.g. electret-type
• CPC Class Codes: Y10T 29/49005 Acoustic transducer

Abstract

An ultrasonic transducer structure, an ultrasonic transducer, and a method of manufacturing the ultrasonic transducer are provided. The ultrasonic transducer structure includes a driving wafer that includes a driving circuit; and an ultrasonic transducer wafer that is disposed on the driving wafer and includes a first wafer in which a via-hole is formed, a first insulating layer formed on the first wafer, a second wafer spaced apart from the first insulating layer, and a cavity formed between the first insulating layer and the second wafer.

Claims

1. An ultrasonic transducer structure comprising:

a driving wafer that comprises a driving circuit; and

an ultrasonic transducer wafer that is disposed on the driving wafer, the ultrasonic transducer wafer comprising a first wafer having a via-hole therein, a first insulating layer disposed on the first wafer, a second wafer spaced apart from the first insulating layer, and a cavity provided between the first insulating layer and the second wafer.

2. The ultrasonic transducer structure of claim 1, wherein the driving wafer is an application-specific integrated circuit wafer.

3. The ultrasonic transducer structure of claim 1, wherein the first wafer is a low-resistivity silicon wafer.

4. The ultrasonic transducer structure of claim 1, wherein the second wafer is a silicon wafer.

5. The ultrasonic transducer structure of claim 4, wherein the second wafer is a silicon-on-insulator wafer.

6. The ultrasonic transducer structure of claim 1, wherein the ultrasonic transducer wafer is directly bonded to the driving wafer.

7. The ultrasonic transducer structure of claim 1, wherein the driving wafer and the ultrasonic transducer wafer are bonded to each other by using eutectic bonding or polymer bonding.

8. The ultrasonic transducer structure of claim 1, wherein each of the driving wafer and the ultrasonic transducer wafer comprises a plurality of connecting portions, and each of the plurality of connecting portions is formed of at least one material selected from the group consisting of gold (Au), copper (Cu), stannum (Sn), silver (Ag), aluminum (Al), platinum (Pt), titanium (Ti), nickel (Ni), and chromium (Cr).

9. An ultrasonic transducer comprising:

a first substrate that comprises a driving circuit;

a first insulating layer that is disposed on the first substrate;

a second substrate that is disposed on the first insulating layer and has a via-hole therein;

a support portion that is disposed above and spaced apart from the second substrate;

a thin film that is supported by the support portion and is spaced apart from the second substrate; and

a cavity between the second substrate and the thin film,

wherein the first substrate and the second substrate are directly bonded to each other with the first insulating layer therebetween.

10. The ultrasonic transducer of claim 9, wherein the first substrate is an application-specific integrated circuit substrate.

11. The ultrasonic transducer of claim 9, wherein the second substrate is a low-resistivity silicon substrate.

12. The ultrasonic transducer of claim 9, wherein the third substrate is a silicon substrate.

13. The ultrasonic transducer of claim 9, wherein the first substrate and the second substrate are bonded to each other by using eutectic bonding or polymer bonding.

14. The ultrasonic transducer of claim 9, wherein each of the first substrate and the second substrate comprises a plurality of connecting portions, and each of the connecting portions is formed of at least one material selected from the group consisting of gold (Au), copper (Cu), stannum (SN), silver (Ag), aluminum (Al), platinum (Pt), titanium (Ti), nickel (Ni), and chromium (Cr).

15. A method of manufacturing an ultrasonic transducer, the method comprising:

depositing a first insulating layer on a first wafer;

patterning the first insulating layer to form a gap in the first insulating layer;

depositing a second insulating layer on a second wafer;

bonding the first wafer to the second wafer such that the first insulating layer and the second insulating layer face each other;

forming a via-hole in the second wafer;

depositing a third insulating layer on an exposed surface of the second wafer;

forming a metal layer on the third insulating layer;

forming a first connecting portion and a second connecting portion by patterning the metal layer;

preparing a third wafer that comprises a driving circuit, and a third connecting portion and a fourth connecting portion respectively corresponding to the first connecting portion and the second connecting portion; and

bonding the third wafer to the second wafer.

16. The method of claim 15, wherein the first wafer is a silicon-on-insulating (SOI) wafer that comprises a first silicon layer, an insulating layer, and a second silicon layer.

17. The method of claim 16, further comprising, after the bonding of the third wafer to the second wafer, removing the insulating layer and the second silicon layer of the SOI wafer.

18. The method of claim 15, wherein the first insulating layer is formed of SiO₂.

19. The method of claim 15, wherein the second wafer is a low-resistivity silicon wafer.

20. The method of claim 15, further comprising, before the forming of the via-hole, polishing the second wafer.

21. The method of claim 15, wherein the bonding of the first wafer to the second wafer comprises bonding the first wafer to the second wafer by using silicon direct bonding.

22. The method of claim 15, wherein the bonding of the third wafer to the second wafer comprises the bonding of the third wafer to the second wafer by using eutectic bonding or polymer bonding.

23. The method of claim 15, wherein the third wafer is an application-specific integrated circuit (ASIC) wafer.

24. The method of claim 15, further comprising, after the first wafer, the second wafer, and the third wafer are bonded to each other to form a wafer structure, slicing the wafer structure in units of chips to produce ultrasonic transducers.

25. A method of manufacturing an ultrasonic transducer, the method comprising:

bonding an ultrasonic transducer wafer including a plurality of chips to a wafer including a driving circuit in a wafer-to-wafer manner to form an ultrasonic transducer structure; and

slicing the wafer structure in units of the chips to produce individual ultrasonic transducers.

26. The method of claim 25, wherein the wafers are bonded without using a through-silicon via wafer.

27. The method of claim 25, wherein the wafers are bonded without using a flip-chip bonding.