Method of fabricating non-volatile memory device

1. A method of fabricating a non-volatile memory device, comprising the steps of:

sequentially forming a first insulating layer, a first conductor layer, and a second insulating layer on a semiconductor substrate;

patterning the second insulating layer, the first conductor layer, and the first insulating layer to expose a prescribed portion of the semiconductor substrate;

forming a trench having a prescribed depth in the semiconductor substrate by removing the exposed portion of the semiconductor substrate;

forming a third insulating layer on the second insulating layer including the trench;

planarizing the third insulating layer to remove the second insulating layer until the first conductor layer is exposed;

forming a fourth insulating layer on the exposed first conductor layer and the remaining third insulating layer; and

forming a second conductor layer on the fourth insulating layer.

2. The method of claim 1 , wherein the first insulating layer is a thermal oxide layer by thermal oxidation, the first and second conductor layers are polysilicon layers, the second and third insulating layers are oxide layers by chemical vapor deposition, and the fourth insulating layer is an oxide/nitride/oxide layer.

3. The method of claim 2 , wherein the second insulating layer is the oxide layer by high density plasma chemical vapor deposition.

4. The method of claim 1 , wherein the first insulating layer is 50˜200 Å thick, the first conductor layer is 500˜3,000 Å thick, and the second insulating layer is 500˜4,000 Å thick.

5. The method of claim 1 , wherein the second insulating layer is removed in the planarizing step using the first conductor layer as an etch stop layer.

6. The method of claim 1 , wherein the second insulating layer is removed by chemical mechanical polishing.