Method of manufacturing liquid crystal display device

1. A method of manufacturing a liquid crystal display device comprising:

preparing a substrate defined into a P-channel thin film transistor formation region and an N-channel thin film transistor formation region;

forming first and second active patterns on the P-channel and N-channel thin film transistor formation regions of the substrate using a first masking process, respectively;

forming a first insulation film and a first conductive film on the substrate provided with the first and second active patterns;

forming a first gate electrode, which is consisted of the first conductive film, on the P-channel thin film transistor formation region of the substrate using a second masking process;

forming a P drain region, a P source region, and a P channel region between the P drain and source regions on the first active pattern using the first gate electrode;

forming a second gate electrode, which is consisted of the first conductive film, on the N-channel thin film transistor formation region of the substrate using a third masking process;

forming an N drain region, an N source region, and an N channel region between the N drain and source regions on the second active pattern using the second gate electrode;

forming a second insulation film on the substrate with the N drain, source, and channel regions;

selectively removing the first and second insulation films using a fourth masking process to form first contact holes partially exposing the respective N and P source regions and second contact holes partially exposing the respective N and P drain regions;

forming a second conductive film on the substrate provided with the first and second contact holes;

forming N and P source electrodes, which are electrically connected to the N and P source regions through the first contact holes, and N and P drain electrodes which are electrically connected to the N and P drain regions through the second contact holes, using a fifth masking process;

forming a third insulation film and a third conductive film on the substrate provided with the N and P drain electrodes;

forming third contact holes, which pass through the third insulation film, and a common electrode on the third insulation using a sixth masking process;

forming a fourth insulation film on the substrate provided with the third contact holes and the common electrode;

forming fourth contact holes, which pass through the fourth insulation film and expose the respective N and P drain electrodes, using a seventh masking process;

forming a fourth conductive film on the substrate with the fourth contact holes; and

forming a pixel electrode, which is electrically connected to the N and P drain electrodes through the fourth contact holes, using a eighth masking process.

2. The method claimed as claim 1 , wherein the formation of the third contact holes and the common electrode includes:

forming a first photo resist pattern on the substrate provided with the third insulation film and the third conductive film through the sixth masking process;

exposing the substrate with the first photo resist pattern to light to form exposed regions on the third insulation film under the third conductive film;

removing portions of the third conductive film exposed by the first photo resist pattern which is used as a mask;

developing the substrate with the partially removed third conductive film to form the third contact holes which pass through the third insulation film and expose the N and P drain electrodes;

forming a second photo resist pattern by ashing the first photo resist pattern; and

removing the exposed third conductive film using the second photo resist pattern as a mask to form the common electrode.

3. The method claimed as claim 2 , wherein the sixth masking process uses a diffraction mask defined into a transmission region, a semipermeable region with slits, and a blocking region.

4. The method claimed as claim 3 , wherein the blocking region is opposite to a common electrode formation region, the transmission region is opposite to a third contact hole formation region, and the semipermeable region is opposite a region between the common electrode formation region and the third contact hole formation region.

5. The method claimed as claim 2 , wherein the second photo resist pattern remains only a common electrode formation region by completely removing the first photo resist pattern from a region between a third contact hole formation region and the common electrode formation region.

6. The method claimed as claim 1 , further comprises forming a buffer layer on the substrate before the formation of the first and second active patterns.

7. The method claimed as claim 1 , wherein the first and second active patterns are formed by crystallizing an amorphous silicon thin film into a polycrystalline silicon thin film.

8. The method claimed as claim 1 , wherein the P drain and source regions are formed by implanting p+ ions into the first active pattern using the first gate electrode as a mask, and the N drain and source regions are formed by implanting n+ ions into the second active pattern using the second gate electrode as a mask.

9. The method claimed as claim 1 , wherein the first and second conductive films are formed from an opaque conductive material, the third and fourth conductive films are formed from a transparent conductive material, and the third insulation is formed from an organic insulation material.

10. The method claimed as claim 1 , wherein the fourth contact hole is formed at the same position as the third contact hole and in a smaller size than that of the third contact hole.

11. The method claimed as claim 1 , further comprises forming p− lightly doped drain (LDD) regions between the P channel and drain regions and between the P channel and source regions after the formation of the P drain, source, and channel regions.

12. The method claimed as claim 1 , further comprises forming n− lightly doped drain (LDD) regions between the N channel and drain regions and between the N channel and source regions after the formation of the N drain, source, and channel regions.