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US 7,678,601 B2Granted
Method of forming an acceleration sensor
AssigneeTexas Instruments Incorporated
InventorsHiroyuki Tomomatsu, Kazuhiko Watanabe, Tetsuya Tada, Toshiyuki Tani
Life of this patent
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Abstract
A method of forming a MEMS structure over active circuitry in a semiconductor body includes forming active circuitry in a semiconductor body, and forming the MEMS structure over the active circuitry, wherein at least a portion of the MEMS structure spatially overlaps the active circuitry.
Claims28
A method of forming a MEMS structure over active circuitry in a semiconductor body, comprising:
- forming active circuitry in a semiconductor body, wherein the active circuitry comprises one or more transistor devices;
- and
- forming the MEMS structure over the active circuitry, wherein at least a portion of the MEMS structure spatially overlaps the active circuitry;
- wherein forming the MEMS structure comprises forming a lower and an upper electrode separated by a gap established by depositing and at least partially removing a sacrificial gap layer comprising aluminum;
- the lower and upper electrodes being electrically isolated from one another, thereby forming a capacitor structure, wherein a change in acceleration experienced by the semiconductor body causes a change in the gap and thus a change in the capacitance of the capacitor structure.
2 more elements
A method of forming an acceleration sensor, comprising:
- forming active circuitry in a semiconductor body;
- and
- forming the acceleration sensor over the active circuitry, wherein the acceleration sensor spatially overlaps at least a portion of the active circuitry, and forming the acceleration sensor further comprises:
- forming a lower electrode layer over the active circuitry;
- forming a sacrificial gap layer over the lower electrode layer;
- forming an upper electrode layer over the sacrificial gap layer;
- and
- patterning the electrode layers and at least partially removing the sacrificial gap layer, thereby leaving a gap having a distance associated with a thickness of the gap layer between lower and upper electrodes;
- wherein forming the acceleration sensor includes forming contact structures for the underlying active circuitry laterally displaced from the electrodes concurrently with the forming of the sacrificial gap layer.
6 more elements
A method of forming an acceleration sensor, comprising:
- forming active circuitry in a semiconductor body;
- and
- forming the acceleration sensor over the active circuitry;
- wherein the acceleration sensor spatially overlaps at least a portion of the active circuitry;
- and forming the acceleration sensor comprises:
- forming a conductive lower electrode layer by sputtering or physical vapor deposition at a temperature less than about 600 degrees-C.;
- forming an insulative lower electrode protective layer over the lower electrode layer with a chemical vapor deposition process at a temperature less than about 600 degrees-C.;
- forming a conductive sacrificial gap layer over the insulative lower electrode protective layer with a deposition process having a temperature less than about 600 degrees-C.;
- forming a first insulative upper electrode protective layer over the sacrificial gap layer with a chemical vapor deposition process at a temperature less than about 600 degrees-C.;
- forming a conductive upper electrode layer over the first insulative upper electrode protective layer by sputtering or physical vapor deposition at a temperature less than about 600 degrees-C.;
- forming a second insulative upper electrode protective layer over the upper electrode layer with a chemical vapor deposition process at a temperature less than about 600 degrees-C., wherein the first and second insulative upper electrode protective layers encapsulate the upper electrode layer;
- patterning the first and second insulative upper electrode protective layers to expose the sacrificial gap layer;
- and
- at least partially removing the sacrificial gap layer, thereby defining a gap between the insulative lower electrode protective layer and the first insulative upper electrode protective layer;
- wherein forming the acceleration sensor includes forming contact structures for the underlying active circuitry concurrently with the forming of the sacrificial gap layer.
12 more elements
A method of forming MEMS structure over active circuitry in a semiconductor body, comprising:
- forming active circuitry in a semiconductor body;
- and
- forming the MEMS structure over the active circuitry, wherein at least a portion of the MEMS structure spatially overlaps the active circuitry, and forming the MEMS structure includes forming a lower electrode layer, a first protective layer over the lower electrode layer, an aluminum sacrificial layer over the first protective layer, a second protective layer over the aluminum sacrificial layer, and an upper electrode layer over the aluminum sacrificial layer by processes not exceeding 600 degrees-C.;
- and patterning and etching the thus formed layers to define upper and lower electrodes separated by a gap established by removal of at least portions of the aluminum sacrificial layer.
1 more element
Dependencies are inferred from the claim text.