Method of forming a capacitive micromachined ultrasonic transducer (CMUT)

US8324006B1 · kind B1 · utility

Assignee

• NATIONAL SEMICONDUCTOR CORPORATION · US

Inventors

• Steven J. Adler · Cape Elizabeth, US
• Peter Johnson · Sunnyvale, US
• Ira Oaktree Wygant · Palo Alto, US

Key dates

• Filing date: Oct 28, 2009
• Grant date: Dec 4, 2012
• Expiry date: Sep 15, 2030

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B06B1/0292
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

A method includes forming first isolation trenches in a first side of a first semiconductor-on-insulator (SOI) structure to electrically isolate multiple portions of the first SOI structure from each other. The method also includes bonding a second SOI structure to the first SOI structure to form multiple cavities between the SOI structures. The method further includes forming conductive plugs through a second side of the first SOI structure and forming second isolation trenches in the second side of the first SOI structure around the conductive plugs. In addition, the method includes removing portions of the second SOI structure to leave a membrane bonded to the first SOI structure. The isolated portions of the first SOI structure, the cavities, and the membrane form multiple capacitive micromachined ultrasonic transducer (CMUT) elements. Each CMUT element is formed in one of the isolated portions of the first SOI structure and includes multiple CMUT cells.