Semiconductor devices and methods of forming thereof
First Claim
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1. A method of forming a semiconductor device, the method comprising:
- forming a sacrificial layer in and over a first surface of a workpiece having the first surface and an opposite second surface by a local oxidation process, the sacrificial layer extending into the workpiece;
forming a membrane over the sacrificial layer;
forming a through hole through the workpiece from the second surface to expose a surface of the sacrificial layer; and
removing at least a portion of the sacrificial layer from the second surface to form a cavity under the membrane, wherein the removing of at least the portion of the sacrificial layer removes all of the sacrificial layer extending into the workpiece, wherein the cavity is aligned with the membrane.
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Abstract
In accordance with an embodiment of the present invention, a method of forming a semiconductor device includes forming a sacrificial layer over a first surface of a workpiece having the first surface and an opposite second surface. A membrane is formed over the sacrificial layer. A through hole is etched through the workpiece from the second surface to expose a surface of the sacrificial layer. At least a portion of the sacrificial layer is removed from the second surface to form a cavity under the membrane. The cavity is aligned with the membrane.
16 Citations
26 Claims
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1. A method of forming a semiconductor device, the method comprising:
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forming a sacrificial layer in and over a first surface of a workpiece having the first surface and an opposite second surface by a local oxidation process, the sacrificial layer extending into the workpiece; forming a membrane over the sacrificial layer; forming a through hole through the workpiece from the second surface to expose a surface of the sacrificial layer; and removing at least a portion of the sacrificial layer from the second surface to form a cavity under the membrane, wherein the removing of at least the portion of the sacrificial layer removes all of the sacrificial layer extending into the workpiece, wherein the cavity is aligned with the membrane. - View Dependent Claims (2, 3, 4, 5)
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6. A method of forming a semiconductor device, the method comprising:
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forming a sacrificial layer over a first surface of a workpiece having the first surface and an opposite second surface, patterning the sacrificial layer, wherein forming the patterned sacrificial layer comprises; forming a plurality of trenches in the workpiece from the first surface, the plurality of trenches being separated by a plurality of workpiece regions so that each of the plurality of trenches is separated from an adjacent trench by a workpiece region of the plurality of workpiece regions; filling the plurality of trenches with a fill material; overfilling the fill material above the first surface; and patterning the fill material over the first surface; forming a membrane over the sacrificial layer; forming a through hole through the workpiece from the second surface to expose a surface of the sacrificial layer; removing at least a portion of the sacrificial layer from the second surface to form a cavity under the membrane, wherein the cavity is aligned with the membrane; and removing the plurality of workpiece regions between the plurality of trenches to form a continuous second cavity under the cavity aligned with the membrane. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A method of forming a semiconductor device, the method comprising:
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forming a sacrificial layer over a first surface of a workpiece having the first surface and an opposite second surface, wherein forming the sacrificial layer comprises; forming a first plurality of trenches in the workpiece from the first surface; filling the first plurality of trenches with a first dielectric layer, the first dielectric layer sealing each of the first plurality of trenches to form a first plurality of buried cavities; forming a second plurality of trenches in the workpiece from the first surface, wherein each trench of second plurality of trenches is disposed between adjacent trenches of the first plurality of trenches; filling the second plurality of trenches with a second dielectric layer, the second dielectric layer sealing each of the second plurality of trenches to form a second plurality of buried cavities; and planarizing a top surface of the second dielectric layer over the first surface of the workpiece; patterning the sacrificial layer; forming a membrane over the sacrificial layer; forming a through hole through the workpiece from the second surface to expose a surface of the sacrificial layer; and removing at least a portion of the sacrificial layer from the second surface to form a cavity under the membrane, wherein the cavity is aligned with the membrane. - View Dependent Claims (13, 14, 15, 16)
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17. A method of forming a semiconductor device, the method comprising:
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from a first surface of a workpiece having the first surface and an opposite second surface forming a plurality of trenches comprising a fill material in the workpiece, the plurality of trenches being separated by a plurality of workpiece regions so that each of the plurality of trenches is separated from an adjacent trench by a workpiece region of the plurality of workpiece regions; forming a first sacrificial layer over the plurality of trenches; forming a membrane over the first sacrificial layer; from the second surface removing the fill material from the plurality of trenches to expose a surface of the first sacrificial layer; removing the plurality of workpiece regions between the plurality of trenches to form a continuous cavity; and removing at least a portion of the first sacrificial layer. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. A method of forming a semiconductor device, the method comprising:
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forming a sacrificial layer over a first surface of a workpiece having the first surface and an opposite second surface; patterning the sacrificial layer; forming a plurality of buried cavities in the workpiece from the first surface, wherein the plurality of buried cavities are aligned with the patterned sacrificial layer, wherein each of the plurality of buried cavities is a void fully enclosed within the workpiece; forming a membrane over the sacrificial layer; thinning the workpiece from the second surface; and after thinning the workpiece, removing at least a portion of the sacrificial layer to form a cavity under the membrane, wherein the cavity is aligned with the membrane. - View Dependent Claims (25)
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26. A method of forming a semiconductor device, the method comprising:
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forming a sacrificial layer over a first surface of a workpiece having the first surface and an opposite second surface, wherein forming the sacrificial layer comprises; forming a first plurality of trenches in the workpiece from the first surface; filling the first plurality of trenches with a first dielectric layer, the first dielectric layer sealing each of the first plurality of trenches to form a first plurality of buried cavities; forming a second plurality of trenches in the workpiece from the first surface, wherein each trench of second plurality of trenches is disposed between adjacent trenches of the first plurality of trenches; filling the second plurality of trenches with a second dielectric layer, the second dielectric layer sealing each of the second plurality of trenches to form a second plurality of buried cavities; and planarizing a top surface of the second dielectric layer over the first surface of the workpiece; forming a membrane over the sacrificial layer; thinning the workpiece from the second surface; and after thinning the workpiece, removing at least a portion of the sacrificial layer to form a cavity under the membrane, wherein the cavity is aligned with the membrane.
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Specification