Manufacturing method of semiconductor device

1. A method of manufacturing a semiconductor device, comprising:

forming wells in a semiconductor substrate by implanting ions thereinto;

forming a field oxide layer on the semiconductor substrate;

forming a gate oxide layer on the semiconductor substrate;

forming a first conductive layer on the gate oxide layer and the field oxide layer;

forming a capacitor dielectric layer on the first conductive layer;

forming a second conductive layer on the capacitor dielectric layer;

patterning the first and second conductive layers, the gate oxide layer, and the capacitor dielectric layer so as to form a gate pattern and a capacitor pattern;

selectively wet-etching the first and second conductive layers such that the capacitor dielectric layer becomes outwardly protrudent at a protruding portion thereof;

implanting ions into the semiconductor substrate using the gate pattern and the protruding portion of the capacitor dielectric layer as an implantation mask;

removing the protruding portion of the capacitor dielectric layer so that the patterned capacitor dielectric layer has the same width as a gate electrode and a first capacitor electrode, respectively; and

selectively removing the capacitor dielectric layer on the gate electrode and the second conductive layer on the gate electrode.

2. The method of claim 1 , wherein an etchant solution having a higher etch rate for the first and second conductive layers than that for the capacitor dielectric layer is used for the wet-etching of the first and second conductive layers.

3. The method of claim 1 , wherein the protruding portion of the capacitor dielectric layer is removed by a cleaning process including megasonic cleaning.

4. The method of claim 1 , wherein the capacitor dielectric layer is formed by sequentially depositing an oxide layer, a nitride layer, and another oxide layer.

5. The method of claim 4 , wherein the capacitor dielectric layer is formed to a thickness of 150-200 Å.

6. The method of claim 1 , wherein the gate electrode, a bottom electrode, and a top electrode of the capacitor are formed in the step of wet-etching the first and the second conductive layer.

7. The method of claim 6 , wherein a lightly doped drain region and a source/drain region are formed in the step of implanting ions into the semiconductor substrate using the gate pattern and the protruding portion of the capacitor dielectric layer as an implantation mask.

8. The method of claim 7 , wherein the depth of the lightly doped drain region depends on the thickness of the capacitor dielectric layer.

9. The method of claim 1 , wherein the first conductive layer and the second conductive layer are formed as polysilicon layers, respectively.