Method for fabricating a CMOS image sensor

1 . A method for fabricating a CMOS image sensor comprising:

forming a metal pad in a pad area over a semiconductor substrate divided into an active area and the pad area;

forming a passivation layer on an entire surface of the semiconductor substrate including the metal pad;

selectively removing the passivation layer to expose the metal pad, thereby forming a metal pad open portion;

forming a barrier layer on the entire surface of the semiconductor substrate including the metal pad open portion;

forming R, G and B color filter layers over the barrier layer of the active area;

forming microlenses over the color filter layers;

removing the barrier layer of the pad area; and

performing electron shower to neutralize positive potential trapped in the microlenses.

2 . The method as claimed in claim 1 , wherein the barrier layer is removed by reaction ion etching (RIE).

3 . The method as claimed in claim 2 , further comprising curing using N 2 gas to remove a corrosive material that may remain on a surface of the metal pad when the barrier layer is removed by the RIE.

4 . The method as claimed in claim 1 , further comprising forming an insulating layer on the semiconductor substrate prior to forming the metal pad the semiconductor substrate.

5 . The method as claimed in claim 1 , further comprising forming first planarization layers on the barrier layer of the active area before forming color filter layers over the barrier layer of the active area and forming second planarization layers on the color filter layers before forming the microlenses over the color filter layers.

6 . The method as claimed in claim 1 , wherein the barrier layer is formed of a PE oxide film, PE TEOS, or PE nitride film.

7 . The method as claimed in claim 1 , wherein the barrier layer is formed at a thickness of about 200 Å to 600 Å.

8 . The method as claimed in claim 1 , wherein the metal pad is formed of aluminum.

9 . The method as claimed in claim 1 , wherein the electron shower is performed using electron beam.

10 . The method as claimed in claim 1 , wherein the electron shower is performed using a filament through heat electrons generated by a current flowing in the filament.

11 . The method as claimed in claim 10 , wherein a positive voltage is applied to the semiconductor substrate and a negative voltage is applied to the filament, so that the heat electrons generated from the filament are induced to the semiconductor substrate.

12 . The method as claimed in claim 1 , wherein the electron shower is performed using a magnet or a potential layer to increase electron mobility.

13 . The method as claimed in claim 1 , wherein the electron shower is performed under high vacuum to increase a range of the electrons.

14 . A method of neutralizing a positive potential stored in a microlens of an image sensor device comprising:

performing an electron shower on the microlens.

15 . The method as claimed in claim 14 , wherein the electron shower is performed using a filament through heat electrons generated by a current flowing in the filament.

16 . The method as claimed in claim 15 , wherein a positive voltage is applied to the device and a negative voltage is applied to the filament, so that the heat electrons generated from the filament are induced to the device.

17 . The method as claimed in claim 14 , wherein the electron shower is performed using a magnet or a potential layer to increase electron mobility.

18 . The method as claimed in claim 14 , wherein the electron shower is performed under high vacuum to increase a range of the electrons.