Method for manufacturing CMOS image sensor having microlens therein with high photosensitivity

1. A method for manufacturing a complementary metal oxide semiconductor (CMOS) image sensor having microlenses therein, the method comprising the steps of:

a) preparing a semiconductor substrate including isolation regions and photodiodes therein obtained by a predetermined process;

b) forming an interlayer dielectric (ILD), metal interconnections and a passivation layer formed on the semiconductor substrate in sequence;

c) forming a color filter array having a plurality of color filters on the passivation layer;

d) forming an over-coating layer (OCL) on the color filter array by using a positive photoresist;

e) forming openings in the OCL by patterning the OCL by using a binary mask, wherein the binary mask has coated portions and uncoated portions, the uncoated portions being disposed above boundaries between the color filters; and

f) forming dome-typed microlenses on a patterned OCL.

2. The method as recited in claim 1 , wherein the step f) includes the steps of:

f1) forming a microlens layer on the patterned OCL;

f2) forming rectangular microlenses by patterning the microlens layer into a predetermined configuration; and

f3) carrying out a flow process.

3. The method as recited in claim 2 , wherein the microlens layer uses a silicon oxide-based photoresist material.

4. The method as recited in claim 1 , wherein the uncoated portion of the binary mask has the width less than a maximum resolution in order to form the opening with the width in the range of about 0.1 μm to about 0.2 μm.

5. The method as recited in claim 1 , wherein the width and the height of the opening is adjusted by controlling a dose amount.

6. The method as recited in claim 1 , wherein the coated portions of the binary mask are coated with chromium (Cr).

7. The method as recited in claim 1 , after the step d), further comprising the step of carrying out a curing process for hardening the OCL.

8. A method for manufacturing a CMOS image sensor having microlenses therein, the method comprising the steps of:

a) preparing a semiconductor substrate including isolation regions and photodiodes therein obtained by a predetermined process;

b) forming an ILD, metal interconnections and a passivation layer formed on the semiconductor substrate in sequence;

c) forming a color filter array having a plurality of color filters on the passivation layer;

d) forming an OCL on the color filter array by using a negative photoresist;

e) forming openings in the OCL by patterning the OCL by using a binary mask, wherein the binary mask has coated portions and uncoated portions, the coated portions being disposed above boundaries between the color filters; and

f) forming dome-typed microlenses on a patterned OCL.

9. The method as recited in claim 8 , the step f) includes the steps of:

f1) forming a microlens layer on the patterned OCL;

f2) forming rectangular microlenses by patterning the microlens layer into a predetermined configuration; and

f3) carrying out a flow process.

10. The method as recited in claim 9 , wherein the microlens layer uses a silicon oxide-based photoresist material.

11. The method as recited in claim 8 , wherein the coated portion of the binary mask has the width less than a maximum resolution in order to form the opening with the width in the range of about 0.1 μm to about 0.2 μm.

12. The method as recited in claim 8 , wherein the width and the height of the opening is adjusted by controlling a dose amount.

13. The method as recited in claim 8 , wherein the coated portions of the binary mask are coated with Cr.

14. The method as recited in claim 8 , after the step d), further comprising the step of carrying out a curing process for hardening the OCL.

15. A method for manufacturing a CMOS image sensor having microlenses therein, the method comprising the steps of:

a) preparing a semiconductor substrate including isolation regions and photodiodes therein obtained by a predetermined process;

b) forming an ILD, metal interconnections and a passivation layer formed on the semiconductor substrate in sequence;

c) forming a color filter array having a plurality of color filters on the passivation layer;

d) forming an OCL on the color filter array by using a negative photoresist;

e) forming openings in the OCL by patterning the OCL by using a phase shifted mask (PSM), wherein the PSM has a 0° phase and a 180° phase, boundaries between the 0° phase and the 180° phase being disposed above boundaries between the color filters; and

f) forming dome-typed microlenses on a patterned OCL.

16. The method as recited in claim 15 , the step f) includes the steps of:

f1) forming a microlens layer on the patterned OCL;

f2) forming rectangular microlenses by patterning the microlens layer into a predetermined configuration; and

f3) carrying out a flow process.

17. The method as recited in claim 16 , wherein the microlens layer uses a silicon oxide-based photoresist material.

18. The method as recited in claim 15 , wherein each opening has the width ranging from about 0.03 μm to about 0.1 μm.

19. The method as recited in claim 15 , wherein the width and the height of the opening is adjusted by controlling a dose amount.

20. The method as recited in claim 15 , after the step d), further comprising the step of carrying out a curing process for hardening the OCL.