Image sensor and method of fabricating the same
View Patent ↗An image sensor and a method for fabricating the same are provided. The image sensor includes color filter layers having a photonic crystal for color separation. Since transmittance of the color filter layers is higher than that of a pigment or dye of an organic material and can easily be controlled in an unnecessary wavelength region, the image sensor having high sensitivity and good color reproduction can be fabricated.
1. A method for fabricating an image sensor comprising:
forming a planarization layer for color filter layers on a light-transmitting layer that transmits light received in a photodiode on a silicon substrate;
sputtering or depositing a gold layer on the planarization layer;
depositing a first photoresist layer on the gold layer to form a grid pattern using etching;
performing isotropic etching in the gold layer;
stripping the first photoresist layer;
etching or selectively growing a portion other than the grid pattern of the gold layer to form a trench;
filling a material having different refractive indexes in the trench;
depositing a second photoresist layer; and
planarizing the second photoresist layer using a dry etch-back process, thereby forming the color filter layers.
2. The method of claim 1 , wherein the planarization layer is made of silicon dioxide and wherein the material filling the trench is silicon nitride.
3. The method of claim 1 , wherein the trench is formed by selectively growing silicon monocrystal on the grid pattern.
4. The method of claim 1 , wherein the trench is formed by selectively growing silicon dioxide on the grid pattern.
5. The method of claim 1 , wherein the color filter layers have a photonic crystal for color separation.
6. The method of claim 1 , further comprising forming a plurality of microlenses.
7. The method of claim 1 , further comprising:
depositing a polyimide material on the planarization layer; and
performing curing based on an annealing process.
8. The method of claim 1 , wherein the etching used in depositing a first photoresist layer on the gold layer to form a grid pattern is electron—beam etching.
9. The method of claim 1 , further comprising forming a third photoresist after forming a planarization layer and before sputtering or depositing a gold layer.
10. The method of claim 9 , further comprising planarizing the third photoresist using a dry-etch back process.
11. The method of claim 9 , further comprising planarizing the third photoresist using chemical-mechanical polishing.