Method of manufacturing ultrasound transducer device having acoustic backing

• US 20050046311A1
• Filed: 10/06/2004
• Published: 03/03/2005
• Est. Priority Date: 12/11/2002
• Status: Active Grant

• Current Assignee: Charles E. Baumgartner, David M. Mills, Douglas G. Wildes, Lowell Scott Smith, Robert S. Lewandowski
• Original Assignee: Charles E. Baumgartner, David M. Mills, Douglas G. Wildes, Lowell Scott Smith, Robert S. Lewandowski
• Inventors: Wildes, Douglas G., Smith, Lowell Scott, Mills, David M., Lewandowski, Robert S., Baumgartner, Charles E.
• Granted Patent: US 7,441,321 B2
• Time in Patent Office: Days
• US Class Current: 310/334
• CPC Class Codes: B06B 1/0292 Electrostatic transducers, e.g. electret-type
• CPC Class Codes: B06B 1/0685 on the back only of piezoelectric elements
• CPC Class Codes: B06B 1/0688 with foil-type piezoelectric elements, e.g. PVDF
• CPC Class Codes: G01H 11/06 by electric means
• CPC Class Codes: Y10T 29/49004 including measuring or testing of device or component part
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/4908 Acoustic transducer

Abstract

An ultrasonic transducer device comprising: an ultrasonic transducer array micromachined on a substrate; flexible electrical connections connected to the transducer array; and a body of acoustically attenuative material that supports the substrate and the flexible electrical connections. The acoustic backing material may contain additional features, such as tabs or notches, for use in positioning the transducer on fixtures during manufacturing or positioning the transducer within a housing during final assembly. Tabs or other features that are used only during manufacturing may be subsequently removed from the device. The MUT device itself may also be thinned so as to provide flexibility as desired. The backing material is preferably matched in acoustic impedance to the silicon wafer so as to prevent reflection at the interface of any acoustic energy propagating rearward, i.e., in the direction away from the device front surface. The backing material may also possess a high thermal conductivity to assist in removal of heat from the device.

Claims

1-24. -24. (Canceled).

25. A method of manufacturing an ultrasound transducer comprising the following steps:

attaching a substrate to a layer of acoustic backing material;

thinning said substrate while it is attached to said layer of acoustic backing material; and

micromachining an array of ultrasonic transducer cells on said substrate.

26. The method as recited in claim 25, wherein said thinning step comprises etching, polishing or grinding.

27. The method as recited in claim 25, wherein said backing material attenuates acoustic waves produced by said array of ultrasonic transducer cells that pass through said substrate and into said backing material.

28. The method as recited in claim 27, wherein said backing material is matched in acoustic impedance to the material of said substrate to prevent reflection at an interface of said substrate and said layer of backing material.

29. A method of manufacturing an ultrasound transducer comprising the following steps:

micromachining an array of ultrasonic transducer cells on a substrate;

attaching a front face of said array to a support membrane;

thinning said substrate while supported by said support membrane;

attaching a formed or conformal layer of backing material to said thinned substrate; and

removing said supporting membrane.

30. The method as recited in claim 29, wherein said thinning step comprises etching, polishing or grinding.

31. The method as recited in claim 29, wherein said backing material attenuates acoustic waves produced by said array of ultrasonic transducer cells that pass through said substrate and into said backing material.

32. The method as recited in claim 31, wherein said backing material is matched in acoustic impedance to the material of said substrate to prevent reflection at an interface of said substrate and said layer of backing material.

33. (Canceled).

34. A method of manufacturing an ultrasound transducer comprising the following steps:

attaching a substrate having a first area to a layer of acoustic backing material having a second area greater than said first area, said substrate being placed so that respective portions of said layer of acoustic backing material extend beyond opposing side edges of said substrate;

thinning said substrate while it is attached to said layer of acoustic backing material;

micromachining an array of ultrasonic transducer cells on said substrate; and

trimming off said respective portions of said layer of acoustic backing material subsequent to said micromachining step.