Semiconductor power device having a top-side drain using a sinker trench
First Claim
1. A semiconductor power device comprising:
- a substrate of a first conductivity type;
an epitaxial layer of the first conductivity type over and in contact with the substrate;
a first trench extending into and terminating within the epitaxial layer;
a sinker trench extending from the top surface of the epitaxial layer through the epitaxial layer and terminating within the substrate, the sinker trench being laterally spaced from the first trench, the sinker trench being wider and extending deeper than the first trench, the sinker trench being lined with an insulator only along the sinker trench sidewalls so that a conductive material filling the sinker trench makes electrical contact with the substrate along the bottom of the trench and makes electrical contact with an interconnect layer along the top of the trench.
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Accused Products
Abstract
A semiconductor power device includes a substrate of a first conductivity type and an epitaxial layer of the first conductivity type over and in contact with the substrate. A first trench extends into and terminates within the epitaxial layer. A sinker trench extends from the top surface of the epitaxial layer through the epitaxial layer and terminates within the substrate. The sinker trench is laterally spaced from the first trench, and is wider and extends deeper than the first trench. The sinker trench is lined with an insulator only along the sinker trench sidewalls so that a conductive material filling the sinker trench makes electrical contact with the substrate along the bottom of the trench and makes electrical contact with an interconnect layer along the top of the trench.
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Citations
40 Claims
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1. A semiconductor power device comprising:
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a substrate of a first conductivity type;
an epitaxial layer of the first conductivity type over and in contact with the substrate;
a first trench extending into and terminating within the epitaxial layer;
a sinker trench extending from the top surface of the epitaxial layer through the epitaxial layer and terminating within the substrate, the sinker trench being laterally spaced from the first trench, the sinker trench being wider and extending deeper than the first trench, the sinker trench being lined with an insulator only along the sinker trench sidewalls so that a conductive material filling the sinker trench makes electrical contact with the substrate along the bottom of the trench and makes electrical contact with an interconnect layer along the top of the trench. - View Dependent Claims (2, 3, 4)
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5. A semiconductor power device comprising:
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a substrate of a first conductivity type;
an epitaxial layer of the first conductivity type over and in contact with the substrate;
a well region of a second conductivity type in the epitaxial layer;
a gate trench extending through the epitaxial layer and the well region and terminating within the substrate, the gate trench including a gate dielectric layer lining at least the sidewalls of the gate trench, and a gate electrode at least partially filling the gate trench;
source regions of the first conductivity type in the well region, the source regions flanking the gate trench; and
a sinker trench extending from the top surface of the epitaxial layer through the epitaxial layer and terminating within the substrate, the sinker trench being laterally spaced from the first trench, the sinker trench being wider than the first trench, the sinker trench being lined with an insulator only along the sinker trench sidewalls so that a conductive material filling the sinker trench makes electrical contact with the substrate along the bottom of the trench and makes electrical contact with an interconnect layer along the top of the trench. - View Dependent Claims (6, 7)
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8. A method of forming a semiconductor power device, comprising:
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forming an epitaxial layer over and in contact with a substrate, the epitaxial layer and the substrate being of a first conductivity type;
defining a first opening for forming a first trench and a second opening for forming a sinker trench, the second opening being wider than the first opening;
performing silicon etch to simultaneously etch through the first and second openings to form the first trench and the sinker trench such that the first trench terminates within the epitaxial layer and the sinker trench terminates within the substrate;
lining the sinker trench sidewalls with an insulator;
filling the sinker trench with a conductive material such that the conductive material makes electrical contact with the substrate along the bottom of the sinker trench; and
forming an interconnect layer over the epitaxial layer, the interconnect layer making electrical contact with the conductive material along the top surface of the sinker trench. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of forming a field effect transistor, comprising:
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forming an epitaxial layer over and in contact with a substrate, the epitaxial layer and the substrate being of a first conductivity type;
defining a first opening for forming a gate trench and a second opening for forming a sinker trench, the second opening being wider than the first opening;
performing silicon etch to simultaneously etch through the first and second openings to form the gate trench and the sinker trench such that the gate trench terminates within the epitaxial layer and the sinker trench terminates within the substrate;
lining the sidewalls and bottom of both the sinker trench and the gate trench with an insulator; and
removing the insulator from a lower portion of the sinker trench;
filling the sinker trench and the gate trench with doped polysilicon such that the conductive material makes electrical contact with the substrate along the lower portion of the sinker trench. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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28. A semiconductor power device comprising:
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a plurality of groups of stripe-shaped trenches extending in a silicon region over a substrate;
a contiguous sinker trench completely surrounding each group of the plurality of stripe-shaped trenches so as to isolate the plurality of groups of stripe-shaped trenches from one another, the contiguous sinker trench extending from a top surface of the silicon region through the silicon region and terminating within the substrate, the contiguous sinker trench being lined with an insulator only along the sinker trench sidewalls so that a conductive material filling the contiguous sinker trench makes electrical contact with the substrate along the bottom of the contiguous sinker trench and makes electrical contact with an interconnect layer along the top of the contiguous sinker trench. - View Dependent Claims (29, 30, 31)
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32. A semiconductor power device comprising:
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a plurality of groups of stripe-shaped gate trenches extending in a silicon region over a substrate;
a plurality of stripe-shaped sinker trenches each extending between two adjacent groups of the plurality of groups of stripe-shaped gate trenches, the plurality of stripe-shaped sinker trenches extending from a top surface of the silicon region through the silicon region and terminating within the substrate, the plurality of stripe-shaped sinker trenches being lined with an insulator only along the sinker trench sidewalls so that a conductive material filling each sinker trench makes electrical contact with the substrate along the bottom of the sinker trench and makes electrical contact with an interconnect layer along the top of the sinker trench. - View Dependent Claims (33, 34, 35, 36)
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37. A semiconductor package device housing a die which comprises a power device, the die comprising a silicon region over a substrate, the semiconductor package device comprising:
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a first plurality of trenches extending in the silicon region;
a contiguous sinker trench extending along the perimeter of the die so as to completely surround the first plurality of trenches, the contiguous sinker trench extending from a top surface of the die through the silicon region and terminating within the substrate, the contiguous sinker trench being lined with an insulator only along the sinker trench sidewalls so that a conductive material filling the contiguous sinker trench makes electrical contact with the substrate along the bottom of the contiguous sinker trench and makes electrical contact with an interconnect layer along the top of the contiguous sinker trench; and
a plurality of interconnect balls arranged in a grid array, an outer group of the plurality of interconnect balls electrically connecting to the conductive material in the contiguous sinker trench. - View Dependent Claims (38, 39, 40)
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Specification