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US 12,578,236 B2Granted
Embedded mechanical stopper for thermal sensor device
AssigneeSTMicroelectronics International N.V.
InventorsFederico Vercesi, Silvia Nicoli, Cinzia De Marco
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Abstract
Disclosed herein are thermal sensor devices including TMOS devices with a mass suspended over a cavity by springs extending between a frame and the mass. The thermal sensor devices include stoppers that limit upward and/or downward movement of the springs and therefore the mass. These stoppers are formed from sidewalls supporting a top cap over the frame, springs, and mass. The stoppers are constructed by using various overlapping metal layers during fabrication. Details of forming the stoppers using these overlapping metal layers are contained here.
Claims16
A method of forming a thermal sensing pixel, comprising:
- providing a base substrate having a buried oxide layer thereon, with a silicon layer being on the buried oxide layer, whereby the buried oxide layer and silicon layer are selectively etchable to form a frame structure, spring structures, and a central structure;
- forming an active layer within the silicon layer to include at least one integrated circuit therein, the at least one integrated circuit formed in a position overlying the central structure;
- forming a first insulator layer on the active layer;
- forming a first metal layer in the first insulator layer, with metallized portions of the first metal layer overlying the spring structures;
- forming a second insulator layer on the first metal layer;
- forming a second metal layer in second insulator layer, and with a central metallized portion of the second metal layer overlying the at least one integrated circuit and central structure;
- forming a third insulator layer on the second metal layer;
- forming a third metal layer in the third insulator layer;
- performing an etch to remove the third insulator layer, portions of the second insulator layer except those underlying metallized portions of the third metal layer, and portions of the first insulator layer except those underlying metallized portions of the third metal layer and second metal layer, as well as portions of the silicon layer and buried oxide layer underlying metallized portions of the third metal layer, second metal layer, and first metal layer to thereby form the frame structure, spring structures, and central structure;
- and
- removing the metallized portions of the third metal layer, second metal layer, and first metal layer to thereby form a frame defined by the frame structure, springs defined by the spring structures, and a mass defined by the central structure, with a first stopper being defined by exposed portions of a bottom surface of the second insulator layer.
8 more elements
A method of forming a thermal sensing pixel, comprising:
- providing a base substrate having a buried oxide layer thereon, with a silicon layer being on the buried oxide layer, whereby the buried oxide layer and silicon layer are selectively etchable to form a frame structure, spring structures, and a central structure;
- forming an active layer within the silicon layer to include at least one integrated circuit therein, the at least one integrated circuit formed in a position overlying the central structure;
- forming a first insulator layer on the active layer;
- forming a first metal layer in the first insulator layer, with metallized portions of the first metal layer overlying the spring structures;
- forming a second insulator layer on the first metal layer;
- forming a second metal layer in second insulator layer, and with a central metallized portion of the second metal layer overlying the at least one integrated circuit and central structure;
- performing an etch to remove portions of the second insulator layer except those underlying metallized portions of the first insulator layer except those underlying metallized portions of the second metal layer, as well as portions of the silicon layer and buried oxide layer underlying metallized portions of the second metal layer and first metal layer to thereby form the frame structure, spring structures, and central structure;
- and
- removing the metallized portions of the second metal layer and first metal layer to thereby form a frame defined by the frame structure, springs defined by the spring structures, and a mass defined by the central structure, with a first stopper being defined by exposed portions of a bottom surface of the second insulator layer.
6 more elements
Dependencies are inferred from the claim text.