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 |
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.
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