Method of manufacturing non-photosensitive polyimide passivation layer

1. A method of manufacturing non-photosensitive polyimide passivation layer, the method comprising:

a) providing a wafer on which a non-photosensitive polyimide passivation layer is to be formed;

b) spin-coating a non-photosensitive polyimide layer over the wafer and baking it;

c) depositing a silicon dioxide thin film over the non-photosensitive polyimide layer;

d) spin-coating a photoresist layer over the silicon dioxide thin film and baking it;

e) exposing and developing the photoresist layer to form a photoresist pattern;

f) etching the silicon dioxide thin film by using the photoresist pattern as a mask to form a silicon dioxide pattern;

g) removing the patterned photoresist layer;

h) dry etching the non-photosensitive polyimide layer by using the silicon dioxide pattern as a mask to form a non-photosensitive polyimide pattern;

i) removing the patterned silicon dioxide thin film; and

j) forming an imidized polyimide passivation layer by curing the patterned non-photosensitive polyimide layer.

2. The method according to claim 1 , wherein in step a), a top-layer aluminum wiring & pad are formed on the wafer, or a top-layer aluminum wiring & pad and a patterned dielectric passivation film are formed on the wafer.

3. The method according to claim 1 , wherein in step b), the non-photosensitive polyimide layer is made of a material mainly composed of a polyamic acid precursor that is not photosensitive to any light source selected from the group consisting of a G-line with a wavelength of 436 nm, an Mine with a wavelength of 365 nm, a KrF excimer laser with a wavelength of 248 nm and an ArF excimer laser with a wavelength of 193 nm.

4. The method according to claim 1 , wherein in step b), the spin-coated non-photosensitive polyimide layer is baked at a temperature of 50° C. to 200° C. for 30 seconds to 5 hours; and the baked non-photosensitive polyimide layer has a thickness of 1 μm to 50 μm.

5. The method according to claim 4 , wherein in step b), the spin-coated non-photosensitive polyimide layer is baked at a temperature of 130° C. for 5 minutes.

6. The method according to claim 1 , wherein in step c), the silicon dioxide thin film is grown by using a low-temperature oxidation method.

7. The method according to claim 6 , wherein the low-temperature oxidation method is a plasma enhanced chemical vapor deposition method or a photo-chemical vapor deposition method, with a reaction temperature of lower than 300° C.

8. The method according to claim 6 , wherein the low-temperature oxidation method is a high-density plasma chemical vapor deposition with a reactant gas including silane, oxygen and argon, a reaction temperature of 80° C. to 150° C., a gas pressure of 0.5 millitorr to 20 millitorr, and a radio frequency power of 500 W to 2000 W.

9. The method according to claim 1 , wherein in step c), the grown silicon dioxide thin film has a thickness of 50 Å to 5000 Å.

10. The method according to claim 1 , wherein in step d), the spin-coated photoresist layer has a thickness of 0.5 μm to 50 μm after being baked.

11. The method according to claim 1 , wherein in step e), the photoresist layer is exposed by using one light source selected from the group consisting of a G-line with a wavelength of 436 nm, an Mine with a wavelength of 365 nm, a KrF excimer laser with a wavelength of 248 nm and an ArF excimer laser with a wavelength of 193 nm.

12. The method according to claim 11 , wherein in step e), the photoresist layer is exposed by using an Mine light source with a wavelength of 365 nm.

13. The method according to claim 1 , wherein in step h), the dry etching process is a plasma dry etching process with a source radio frequency power of 100 W to 1500 W and a gas pressure of 20 millitorr to 2000 millitorr by using oxygen as a main etching gas, the oxygen having a flow rate of 50 SCCM to 2000 SCCM.

14. The method according to claim 1 , wherein in step j), the curing process is performed at a temperature of 200° C. to 500° C. for 30 minutes to 120 minutes.

15. The method according to claim 14 , wherein in step j), the curing process is performed at a temperature of 400° C. for 60 minutes.