Deep well process for MEMS pressure sensor
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsShao-Chi Yu, Hong-Seng Shue
Life of this patent
Estimating the term…
Abstract
A micromechanical systems (MEMs) pressure sensor includes a semiconductor substrate having a deep well located within a first surface and a cavity located within a second, opposing surface. The semiconductor substrate has a first doping type. The deep well has a second doping type, with a gradient doping profile, thereby forming a PN junction within the substrate. The cavity forms a diaphragm, which is a substrate section that is thinner than the surrounding substrate sections, that comprises the deep well. One or more pizeoresistor elements are located within the deep well. The piezoresistors are sensitive to deformations, such as bending, in the diaphragm caused by changes in the pressure of the cavity.
Claims20
A method of micro-electro mechanical system (MEMs) processing, comprising:
- forming a deep well within a first side of a semiconductor substrate having a first doping type, wherein the deep well has a second doping type;
- forming one or more shallow wells having the first doping type within the deep well, wherein the one or more shallow wells operate as resistive elements within the deep well;
- and
- selectively etching a second side of the semiconductor substrate by performing an electrochemically controlled etching (ECE) process to form a cavity abutting the deep well, resulting in a diaphragm structure that operates as a piezoresistor that is configured to measure pressure within the cavity.
A micro-electro mechanical system (MEMs) pressure sensor, comprising:
- a semiconductor substrate having a first doping type;
- a deep well located within a first side of the substrate to a depth, wherein the deep well has a second doping type having a gradient doping profile;
- and
- a cavity disposed within a second side of the substrate at a position opposing the deep well, such that the deep well abuts the cavity;
- wherein the cavity forms a pliable diaphragm within the substrate having a thickness that is defined by the depth of the deep well.
A MEMs pressure sensor, comprising:
- a p-type non-epitaxial silicon substrate;
- a diaphragm located within a first side of the p-type non-epitaxial silicon substrate;
- an n-type deep well having a gradient doping profile and located within the diaphragm;
- one or more p-type shallow wells located within the n-type deep well that operates as piezoelectric resistors;
- and
- a cavity located within a second side of the p-type non-epitaxial silicon substrate and abutting the diaphragm;
- wherein a pressure within the cavity is configured to generate a force that acts upon the diaphragm to change the piezoelectric resistors' resistance as a function of pressure difference applied on the diaphragm.
Dependencies are inferred from the claim text.