Semiconductor memory device and manufacturing method thereof
First Claim
1. A manufacturing method of a semiconductor memory device, comprising:
- forming a gate structure on a semiconductor substrate, wherein the gate structure comprises;
a floating gate electrode;
a control gate electrode disposed on the floating gate electrode;
a first oxide layer disposed between the floating gate electrode and the semiconductor substrate; and
a second oxide layer disposed between the floating gate electrode and the control gate electrode;
forming an oxide spacer layer conformally on the gate structure and the semiconductor substrate;
forming a nitride spacer on the oxide spacer layer and on a sidewall of the gate structure; and
performing an oxidation process after the step of forming the nitride spacer, wherein a thickness of an edge portion of the first oxide layer is increased by the oxidation process, and a thickness of an edge portion of the second oxide layer before the oxidation process is equal to the thickness of the edge portion of the second oxide layer after the oxidation process, wherein the oxide spacer layer directly contacts a topmost surface of the control gate electrode during the oxidation process.
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Accused Products
Abstract
A manufacturing method of a semiconductor memory device includes the following steps. A gate structure is formed on a semiconductor substrate. The gate structure includes a floating gate electrode, a control gate electrode, a first oxide layer, and a second oxide layer. The control gate electrode is disposed on the floating gate electrode. The first oxide layer is disposed between the floating gate electrode and the semiconductor substrate. The second oxide layer is disposed between the floating gate electrode and the control gate electrode. An oxide spacer layer is conformally on the gate structure and the semiconductor substrate. A nitride spacer is formed on the oxide spacer layer and on a sidewall of the gate structure. An oxidation process is performed after the step of forming the nitride spacer. A thickness of an edge portion of the first oxide layer is increased by the oxidation process.
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Citations
21 Claims
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1. A manufacturing method of a semiconductor memory device, comprising:
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forming a gate structure on a semiconductor substrate, wherein the gate structure comprises; a floating gate electrode; a control gate electrode disposed on the floating gate electrode; a first oxide layer disposed between the floating gate electrode and the semiconductor substrate; and a second oxide layer disposed between the floating gate electrode and the control gate electrode; forming an oxide spacer layer conformally on the gate structure and the semiconductor substrate; forming a nitride spacer on the oxide spacer layer and on a sidewall of the gate structure; and performing an oxidation process after the step of forming the nitride spacer, wherein a thickness of an edge portion of the first oxide layer is increased by the oxidation process, and a thickness of an edge portion of the second oxide layer before the oxidation process is equal to the thickness of the edge portion of the second oxide layer after the oxidation process, wherein the oxide spacer layer directly contacts a topmost surface of the control gate electrode during the oxidation process. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A semiconductor memory device, comprising:
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a semiconductor substrate; and a gate structure disposed on the semiconductor substrate, wherein the gate structure comprises; a floating gate electrode; a control gate electrode disposed on the floating gate electrode; a first oxide layer disposed between the floating gate electrode and the semiconductor substrate, wherein a thickness of an edge portion of the first oxide layer is larger than a thickness of a center portion of the first oxide layer; a second oxide layer disposed between the floating gate electrode and the control gate electrode, wherein a thickness of an edge portion of the second oxide layer is substantially equal to a thickness of a center portion of the second oxide layer; and a first oxide spacer disposed on a sidewall of the gate structure, wherein the center portion of the first oxide layer is curved and the thickness of the edge portion of the first oxide layer is substantially equal to a thickness of the first oxide spacer. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. A semiconductor memory device, comprising:
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a semiconductor substrate; and a gate structure disposed on the semiconductor substrate, wherein the gate structure comprises; a floating gate electrode; a control gate electrode disposed on the floating gate electrode; a first oxide layer disposed between the floating gate electrode and the semiconductor substrate, wherein a thickness of an edge portion of the first oxide layer is larger than a thickness of a center portion of the first oxide layer; and a second oxide layer disposed between the floating gate electrode and the control gate electrode, wherein a thickness of an edge portion of the second oxide layer is substantially equal to a thickness of a center portion of the second oxide layer; and an oxide spacer layer disposed on a sidewall of the gate structure, wherein a thickness of the oxide spacer layer is larger than the thickness of the center portion of the first oxide layer, wherein the center portion of the first oxide layer is curved and the thickness of the edge portion of the first oxide layer is substantially equal to the thickness of the oxide spacer layer.
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Specification