Ultrasonic transducer and method for manufacturing the same
AssigneeHitachi, Ltd.
InventorsShuntaro Machida, Hiroshi Fukuda
Life of this patent
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Abstract
A technology capable of preventing the degradation of operation reliability of CMUT when a lower electrode for CMUTs arranged in an array is divided in order to control the CMUTs independently is provided. Also, a technology capable of preventing the formation of a convex or concave distortion in an insulating film (membrane) of the cavity is provided. For its achievement, a size of a lower electrode divided for independently controlling each CMUT is set to be larger than that of a cavity. Also, a size of an upper electrode of the CMUT is set to be larger than that of the cavity.
Claims11
An ultrasonic transducer comprising:
- (a) a first electrode which can be controlled independently by an individual ultrasonic transducer;
- (b) a cavity layer which is formed on said first electrode;
- (c) an insulating film which is formed so as to cover said cavity layer;
- and
- (d) a second electrode which is formed on said insulating film,
- wherein a size of said second electrode is larger than that of said cavity layer.
An ultrasonic transducer comprising:
- (a) a first electrode which can be controlled independently by an individual ultrasonic transducer;
- (b) a cavity layer which is formed on said first electrode;
- (c) an insulating film which is formed so as to cover said cavity layer;
- and
- (d) a second electrode which is formed on said insulating film,
- wherein a size of said first electrode and a size of said second electrode are larger than that of said cavity layer.
A method for manufacturing an ultrasonic transducer comprising:
- (a) a step of forming a first electrode which can be controlled independently by an individual ultrasonic transducer;
- (b) a step of forming a sacrifice layer on said first electrode;
- (c) a step of forming a first insulating film so as to cover said sacrifice layer;
- (d) a step of forming a second electrode on said first insulating film;
- (e) a step of forming a second insulating film so as to cover said second electrode and said first insulating film;
- (f) a step of forming an opening which penetrates said first insulating film and said second insulating film to reach said sacrifice layer;
- and
- (g) a step of forming a cavity layer by removing said sacrifice layer utilizing said opening,
- wherein said second electrode is formed so as to be larger than said cavity layer.
Dependencies are inferred from the claim text.