Plasma chemical vapor deposition apparatus

1. A chemical vapor deposition apparatus including a chamber with an outlet formed at a lower portion thereof; a source gas introduction tube, a reactant gas introduction tube and a purge gas introduction tube for respectively supplying process gases into the chamber; a showerhead with a plurality of injection holes for injecting the process gases supplied through the introduction tubes; and a heater for supporting a wafer or substrate on which a thin film is deposited and for serving as a heat source, the apparatus comprising:

an RF power source connection portion connectable to an external RF power source and installed on an upper side of the chamber;

an RF electrode plate installed within the chamber and spaced by a predetermined gap from an inner upper surface of the chamber and spaced by a predetermined gap from an upper surface of the showerhead, said showerhead is disposed below the RF electrode plate;

the RF power source connection portion and the RF electrode plate are connected with each other through an RF rod so that electric power is supplied from the external RF power source to the RF electrode plate;

wherein plasma is generated in a first buffer portion defined by a gap between the RF electrode plate and the upper surface of the showerhead, by means of the electric power applied from the external RF power source to the RF electrode plate;

wherein the showerhead is divided into a first showerhead and a second showerhead in a vertical direction and a second buffer portion is defined by a space between the two showerheads;

wherein reactant gases are supplied to the first buffer portion where the plasma is generated and are then injected onto the wafer or substrate through the first and second showerhead without contact with the second buffer portion; and

wherein source gases are supplied to the second buffer portion and then injected onto the wafer or substrate through the second showerhead;

wherein the first showerhead having a plurality of injection tubes for uniformly injecting the reactant gases or radicals thereof, and the second showerhead having a plurality of through-holes through which the plurality of the injection tubes are inserted and the plurality of injection holes for uniformly injecting the source gases, said injection tubes of the first showerhead are fitted into the through-holes of the second showerhead;

wherein the first showerhead is connected to the chamber and thus electrically grounded; and

wherein a lower insulation portion for insulating the RF electrode plate from an inner surface of the chamber is installed on the bottom of the RF electrode plate in such a manner that the first buffer portion is defined with a predetermined gap between the RF electrode plate and the first showerhead disposed below the RF electrode plate by means of the lower insulation portion.

2. The chemical vapor deposition apparatus as claimed in claim 1 , wherein at least one reactant gas introduction tube and at least one purge gas introduction tube are installed on a side of the first buffer portion to communicate with each other, and at least one source gas introduction tube and at least one purge gas introduction tube are installed on a side of the second buffer portion to communicate with each other.

3. The chemical vapor deposition apparatus as claimed in claim 1 , wherein an upper insulation portion is installed between the inner upper surface of the chamber and the RF electrode plate.

4. The chemical vapor deposition apparatus as claimed in claim 1 , wherein the RF rod is electrically insulated from the chamber by means of an RF rod insulation portion formed around the RF rod.

5. The chemical vapor deposition apparatus as claimed in claim 1 , wherein the plurality of injection tubes and injection holes are arranged in a grid pattern.

6. The chemical vapor deposition apparatus as claimed in claim 1 , wherein a heater for keeping a top portion of the chamber at a constant temperature is installed on the top of the chamber.