Granted Patent B2

US 7,449,359 · App. 11/319,570 · Granted Nov 11, 2008

Abstract

Claims (15)

1. A method of fabricating a CMOS image sensor, comprising:

forming a plurality of photodiodes on a semiconductor substrate;

alternately forming first insulating interlayers and first metal lines on a plurality of the photodiodes to thereby form the first insulating interlayer on the first metal line;

forming a plurality of inner microlenses on the first insulating interlayer;

alternately forming second insulating interlayers and second metal lines on a plurality of the inner microlenses to thereby form the second insulating interlayer on the second metal line;

forming a device protecting layer on the second insulating interlayer; and

forming a plurality of microlenses on the device protecting layer;

wherein forming a plurality of inner microlenses comprises:

attaching a silicon layer on the first insulating layer wherein oxide layers are coated on top and bottom surfaces of the silicon layer, respectively;

forming a photoresist pattern on the silicon layer to expose an area corresponding to a plurality of the photodiodes;

forming concave recesses by wet etching performed on the silicon layer using the photoresist pattern as a mask; and

forming a nitride layer on the semiconductor substrate including the concave recesses;

wherein forming concave recesses comprises:

generating an inverse triangle type profile by performing the wet etching on the silicon layer;

removing an oxide layer from a top surface of the silicon layer; and rounding the inverse triangle type profile by chemical dry etching to form each of the concave recesses.

Assignments (8)