US 11,883,845 B2
Anti-stiction bottom cavity surface for micromachined ultrasonic transducer devices
Lingyun Miao, Fremont, CA (US); Keith G. Fife, Palo Alto, CA (US); Jianwei Liu, Fremont, CA (US); and Jonathan M. Rothberg, Guilford, CT (US)
Assigned to BFLY OPERATIONS, INC., Burlington, MA (US)
Filed by BFLY OPERATIONS, INC., Burlington, MA (US)
Filed on Jan. 5, 2023, as Appl. No. 18/093,701.
Application 18/093,701 is a continuation of application No. 16/683,652, filed on Nov. 14, 2019, granted, now 11,571,711.
Claims priority of provisional application 62/810,358, filed on Feb. 25, 2019.
Claims priority of provisional application 62/768,048, filed on Nov. 15, 2018.
Prior Publication US 2023/0149976 A1, May 18, 2023
Int. Cl. B06B 1/02 (2006.01); B81B 3/00 (2006.01); B81C 1/00 (2006.01)
CPC B06B 1/0292 (2013.01) [B81B 3/001 (2013.01); B81C 1/00984 (2013.01); B81B 2203/0127 (2013.01); B81B 2203/0315 (2013.01); B81B 2203/0392 (2013.01); B81C 2201/0109 (2013.01); B81C 2201/0125 (2013.01); B81C 2201/0176 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of forming an ultrasonic transducer device, the method comprising:
depositing a first layer on a substrate;
depositing a second layer on the first layer;
patterning the second layer at a region corresponding to a location of a transducer cavity;
depositing a third layer that refills regions created by patterning the second layer;
planarizing the third layer to a top surface of the second layer;
removing the second layer;
conformally depositing a fourth layer over the first layer and the third layer;
defining the transducer cavity in a support layer formed over the fourth layer; and
bonding a membrane to the support layer.