CMOS image sensor and method for fabricating the same
View Patent ↗A CMOS image sensor includes a substrate including a sensing part and a peripheral driving part; a first insulating interlayer formed over an entire surface of the substrate; a first metal line formed on the first insulating interlayer in each of the sensing and peripheral driving parts; a second insulating interlayer formed over the entire surface of the substrate including the first metal line; a second metal line formed on the second insulating interlayer in each of the sensor and peripheral drive parts; an etch-stop layer formed over the entire surface of the substrate including the second metal line; a third insulating interlayer formed on the peripheral driving part of the etch-stop layer; a third metal line formed on the third insulating interlayer; a fourth insulating interlayer formed on the third insulating interlayer including the third metal line, to be disposed in the peripheral driving part; and a fourth metal line formed on the fourth insulating interlayer.
1. A method of fabricating a CMOS image sensor, comprising:
defining a sensing part and a peripheral driving part of a substrate;
forming a first insulating interlayer over a surface of the substrate;
forming a first metal line on the first insulating interlayer in each of the sensing and peripheral driving parts;
forming a second insulating interlayer over the surface of the substrate, including the first metal line;
forming a second metal line on the second insulating interlayer in each of the sensing and peripheral driving parts;
forming an etch-stop layer over the surface of the substrate, including the second metal line;
forming a third insulating interlayer over the surface of the substrate, including the etch-stop layer;
forming a third metal line on the third insulating interlayer in the peripheral driving part;
forming a fourth insulating interlayer on the third insulating interlayer, including the third metal line
forming a fourth metal line on the fourth insulating interlayer in the peripheral driving part; and
removing the fourth insulating interlayer and the third insulating interlayer from the sensing part.
2. The method of claim 1 , wherein removing the third and fourth insulating interlayers from the sensing part is performed by a selective etching process.
3. The method of claim 2 , wherein the selective etching process is one of a wet etching process, a dry etching process, and a combination of the wet etching and dry etching processes.
4. The method of claim 1 , further comprising:
forming a photoresist pattern covering the peripheral driving part; and
using the photoresist pattern as a mask during the selective etching process.
5. The method of claim 1 , further comprising:
forming a color filter layer in the sensing part; and
forming a plurality of microlenses on the color filter layer.
6. The method of claim 5 , further comprising:
forming a planarization layer over surfaces of the substrate to provide a surface for receiving the color filter layer and the plurality of microlenses.
7. The method of claim 1 , wherein the etch-stop layer is a nitride layer.
8. The method of claim 1 , further comprising:
forming a plurality of photodiodes in the substrate; and
forming a plurality of transistors on the substrate,
wherein the first insulating interlayer is formed over the plurality of transistors.