DIRECT CONTACT IN TRENCH WITH THREE-MASK SHIELD GATE PROCESS
First Claim
1. A method for making a shield gate trench semiconductor device, comprising:
- a) applying a trench mask as a first mask to a semiconductor substrate;
b) etching the semiconductor substrate to form trenches TR1, TR2 and TR3 with three widths W1, W2 and W3, respectively, wherein the trench TR3 is widest and deepest and the width W3 of the trench TR3 depends on a depth D2 of the trench TR2;
c) forming first conductive material at the bottom of the trenches TR1, TR2 and TR3 to form a source electrode;
d) forming a second conductive material over the first conductive material in the trenches TR1 and TR2 to form a gate electrode, wherein the first and second conductive materials are separated from each other and from the semiconductor substrate by an insulator material;
e) depositing a first insulator layer on top of the trenches TR1, TR2 and TR3, wherein a top portion of the trench TR3 is filled up with the insulator;
f) forming a body layer in a top portion of the substrate;
g) forming a source layer in a top portion of the body layer;
h) applying a second insulator layer on top of the trenches TR1, TR2 and TR3 and the source;
i) applying a contact mask as a second mask on top of the second insulator layer;
j) forming a source electrode contact in trench TR3, a gate electrode contact in trench TR2, and a source/body contact to the semiconductor substrate; and
k) applying a metal mask as a third mask and forming source metal and gate metal on top of the second insulator layer.
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Accused Products
Abstract
A semiconductor device and a method for making a semiconductor device are disclosed. A trench mask may be applied to a semiconductor substrate, which is etched to form trenches with three different widths. A first conductive material is formed at the bottom of the trenches. A second conductive material is formed over the first conductive material. An insulator layer separates the first and second conductive materials. A first insulator layer is deposited on top of the trenches. A body layer is formed in a top portion of the substrate. A source is formed in the body layer. A second insulator layer is applied on top of the trenches and the source. A contact mask is applied on top of the second insulator layer. Source and gate contacts are formed through the second insulator layer. Source and gate metal are formed on top of the second insulator layer.
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Citations
27 Claims
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1. A method for making a shield gate trench semiconductor device, comprising:
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a) applying a trench mask as a first mask to a semiconductor substrate; b) etching the semiconductor substrate to form trenches TR1, TR2 and TR3 with three widths W1, W2 and W3, respectively, wherein the trench TR3 is widest and deepest and the width W3 of the trench TR3 depends on a depth D2 of the trench TR2; c) forming first conductive material at the bottom of the trenches TR1, TR2 and TR3 to form a source electrode; d) forming a second conductive material over the first conductive material in the trenches TR1 and TR2 to form a gate electrode, wherein the first and second conductive materials are separated from each other and from the semiconductor substrate by an insulator material; e) depositing a first insulator layer on top of the trenches TR1, TR2 and TR3, wherein a top portion of the trench TR3 is filled up with the insulator; f) forming a body layer in a top portion of the substrate; g) forming a source layer in a top portion of the body layer; h) applying a second insulator layer on top of the trenches TR1, TR2 and TR3 and the source; i) applying a contact mask as a second mask on top of the second insulator layer; j) forming a source electrode contact in trench TR3, a gate electrode contact in trench TR2, and a source/body contact to the semiconductor substrate; and k) applying a metal mask as a third mask and forming source metal and gate metal on top of the second insulator layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A semiconductor device comprising:
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a plurality of shield gate trench field effect transistors, each of which includes a conductive shield electrode and a conductive gate electrode formed in a trench TR1; a trench TR3 having a conductive shield electrode formed in a bottom of the trench but not having a conductive gate electrode; a trench TR2 having a conductive gate electrode formed over a conductive shield electrode, wherein the trench TR3 is wider and deeper than the trench TR2; one or more vertical shield electrode contacts configured to directly electrically connect the conductive shield electrode in trench TR3 to a source metal; vertical gate contacts configured to direct electrically connected the conductive gate in trench TR2 to a gate metal, wherein the semiconductor device is made with a 3 mask shield gate process and wherein the trench TR3 is wider and deeper than the trench TR2. - View Dependent Claims (25, 26, 27)
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Specification