US 12,332,127 B2
Sealed force sensor with etch stop layer
Julius Minglin Tsai, San Jose, CA (US); Ryan Diestelhorst, Sunnyvale, CA (US); and Dan Krstyen Benjamin, Marietta, GA (US)
Assigned to NextInput, Inc., Mountain View, CA (US)
Filed by NextInput, Inc., San Jose, CA (US)
Filed on Mar. 6, 2024, as Appl. No. 18/597,341.
Application 18/597,341 is a continuation of application No. 17/860,941, filed on Jul. 8, 2022, granted, now 11,965,787.
Application 17/860,941 is a continuation of application No. 16/761,373, granted, now 11,385,108, issued on Jul. 12, 2022, previously published as PCT/US2018/058928, filed on Nov. 2, 2018.
Claims priority of provisional application 62/580,530, filed on Nov. 2, 2017.
Prior Publication US 2024/0247986 A1, Jul. 25, 2024
Int. Cl. G01L 1/18 (2006.01); B81B 3/00 (2006.01); B81C 1/00 (2006.01); G01L 1/26 (2006.01)
CPC G01L 1/18 (2013.01) [B81B 3/0021 (2013.01); B81C 1/00595 (2013.01); G01L 1/26 (2013.01); B81B 2203/0127 (2013.01); B81C 2201/014 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A microelectromechanical system (MEMS) force sensor, comprising:
a sensor die configured to receive an applied force, the sensor die comprising a first substrate and a second substrate, wherein a cavity is formed in the first substrate, and wherein at least a portion of the second substrate defines a deformable membrane;
an etch stop layer arranged between the first substrate and the second substrate;
a sensing element arranged on a surface of the second substrate, wherein the sensing element is configured to convert a strain on the surface of a membrane substrate to an analog electrical signal that is proportional to the strain;
wherein the etch stop layer is configured for precise thickness control of the deformable membrane of the membrane substrate;
wherein an etch rate of the etch stop layer is different than an etch rate of the first substrate; and
wherein an etch rate ratio between the etch rate of the first substrate and the etch rate of the etch stop layer is between 50 and 150.