CMOS image sensors and methods for fabricating the same
View Patent ↗CMOS image sensors and methods for fabricating the same are disclosed. A disclosed CMOS image sensor comprises: a semiconductor substrate; a photo diode; a microlens located over the photo diode; and a color filter layer located over the microlens.
1. A method for fabricating a CMOS image sensor comprising:
injecting impurity ions into a predetermined region of a semiconductor substrate to form a photo diode;
forming an interlayer insulating film on the semiconductor substrate;
forming a first dielectric film on the interlayer insulating film over the photo diode;
forming a second dielectric film at sidewalls of the first dielectric film to form a microlens; and
forming a third dielectric film on the interlayer insulating film and on the microlens.
2. A method as claimed in claim 1 , wherein an index of refraction of the second dielectric film pattern is higher than an index of refraction of the first dielectric film.
3. A method as claimed in claim 1 , wherein an index of refraction of the first dielectric film and an index of refraction of the third dielectric film are substantially identical.
4. A method as claimed in claim 1 , wherein the first dielectric film has an index of refraction of about 1.3˜1.7, and the second dielectric film has an index of refraction of about 1.8˜2.2.
5. A method as claimed in claim 1 , wherein the first dielectric film is an oxide film, and the second dielectric film is a nitride film.
6. A method as claimed in claim 1 , wherein an area of the first dielectric film is substantially identical to an area of the photo diode.
7. A method as claimed in claim 1 , further comprising forming a color filter layer on the third dielectric film over the photo diode.
8. A method for fabricating a CMOS image sensor comprising:
injecting impurity ions into a predetermined region of a semiconductor substrate to form a photo diode;
forming an interlayer insulating film on the semiconductor substrate;
successively forming first and second dielectric films on the interlayer insulating film;
patterning the first and second dielectric films such that the first and second dielectric films remain on the interlayer insulating film over the photo diode;
forming a third dielectric film at sidewalls of the first dielectric film and second dielectric film to form a microlens; and
forming a fourth dielectric film on the interlayer insulating film and on the microlens.
9. A method as claimed in claim 8 , wherein indices of refraction of the first and second dielectric film are higher than indices of refraction of the second and fourth dielectric films.
10. A method as claimed in claim 8 , wherein an index of refraction the first dielectric film is substantially identical to an index of refraction of the third dielectric film.
11. A method as claimed in claim 8 , wherein the indices of refraction of the first and third dielectric films are about 1.8˜2.2, and the indices of refraction of the second and fourth dielectric films are about 1.3˜1.7.
12. A method as claimed in claim 8 , wherein the first and third dielectric films are nitride films, and the second and fourth dielectric films are oxide films.
13. A method as claimed in claim 8 , wherein areas of the first and second dielectric films are substantially equal to an area of the photo diode.
14. A method as claimed in claim 8 , further comprising forming a color filter layer on the fourth dielectric film over the photo diode.