Air gap fabricating method

1. An air gap fabricating method, comprising:

forming a patterned sacrificial layer over a substrate, a material of the patterned sacrificial layer comprising a germanium-antimony-tellurium alloy;

forming a dielectric layer on the patterned sacrificial layer; and

providing a reactant to react with the patterned sacrificial layer and remove the patterned sacrificial layer, so as to form a structure with an air gap disposed at an original position of the patterned sacrificial layer, wherein the reactant comprises: an organic acid which substantially comprises gallic acid and a solvent.

2. The air gap fabricating method of claim 1 , after the step of removing the patterned sacrificial layer, further comprising a step of

washing the dielectric layer with a deionized water.

3. The air gap fabricating method of claim 2 , after the step of washing the dielectric layer with the deionized water, further comprising a step of dry cleaning the dielectric layer with Isopropyl Alcohol (IPA).

4. The air gap fabricating method of claim 1 , wherein a material of the dielectric layer comprises silicon oxide or silicon nitride.

5. The air gap fabricating method of claim 1 , further comprising a step of covering a multi-layered stack of a semiconductor layer and a metal layer on the dielectric layer.

6. The air gap fabricating method of claim 5 , wherein a material of the semiconductor layer comprises polysilicon or amorphous silicon.

7. The air gap fabricating method of claim 5 , wherein a material of the metal layer comprises aluminum, copper, tungsten, nickel, cobalt, titanium, a tungsten-titanium alloy, titanium nitride, tantalum nitride, titanium silicide, tantalum silicide, nickel silicide, or cobalt silicide, alone of combination thereof.

8. The air gap fabricating method of claim 1 , wherein a metal pattern is formed on the substrate, and a metal oxide layer is formed on the metal pattern, when the reactant is used to remove the patterned sacrificial layer, the reactant simultaneously removes the metal oxide layer.

9. The air gap fabricating method of claim 1 , wherein an annealing temperature of the patterned sacrificial layer is from about 100° C. to about 400° C.

10. A semiconductor structure using an air gap as a dielectric layer therein, the air gap is fabricated by a method as claimed in claim 1 .

11. The semiconductor structure of claim 10 is used in a resistive memory device.

12. The semiconductor structure of claim 10 is used in a micro electro-mechanical system (MEMS), a nano electro-mechanical system (NEMS), a semiconductor device with copper wires, a radio frequency device or a dynamic random access memory.

13. An air gap fabricating method, comprising:

forming a patterned sacrificial layer over a substrate, a material of the patterned sacrificial layer comprising a germanium-antimony-tellurium alloy;

forming a dielectric layer on the patterned sacrificial layer; and

providing a reactant to react with the patterned sacrificial layer and remove the patterned sacrificial layer, so as to form a structure with an air gap disposed at an original position of the patterned sacrificial layer, wherein the reactant comprises a hydrogen-helium plasma.

14. The air gap fabricating method of claim 13 , wherein a weight percentage of hydrogen in the hydrogen-helium plasma is substantially about 5%, and a weight percentage of helium in the hydrogen-helium plasma is substantially about 95%.

15. The air gap fabricating method of claim 13 , wherein the hydrogen-helium plasma reacts with the patterned sacrificial layer for about 400 to about 800 seconds.

16. The air gap fabricating method of claim 13 , after the step of removing the patterned sacrificial layer, further comprising a step of

washing the dielectric layer with a deionized water.

17. The air gap fabricating method of claim 16 , after the step of washing the dielectric layer with the deionized water, further comprising a step of dry cleaning the dielectric layer with Isopropyl Alcohol (IPA).

18. The air gap fabricating method of claim 13 , wherein a material of the dielectric layer comprises silicon oxide or silicon nitride.

19. The air gap fabricating method of claim 13 , further comprising a step of covering a multi-layered stack of a semiconductor layer and a metal layer on the dielectric layer.

20. The air gap fabricating method of claim 19 , wherein a material of the semiconductor layer comprises polysilicon or amorphous silicon.

21. The air gap fabricating method of claim 19 , wherein a material of the metal layer comprises aluminum, copper, tungsten, nickel, cobalt, titanium, a tungsten-titanium alloy, titanium nitride, tantalum nitride, titanium silicide, tantalum silicide, nickel silicide, or cobalt silicide, alone of combination thereof.

22. The air gap fabricating method of claim 13 , wherein a metal pattern is formed on the substrate, and a metal oxide layer is formed on the metal pattern, when the reactant is used to remove the patterned sacrificial layer, the reactant simultaneously removes the metal oxide layer.

23. The air gap fabricating method of claim 13 , wherein an annealing temperature of the patterned sacrificial layer is from about 100° C. to about 400° C.

24. A semiconductor structure using an air gap as a dielectric layer therein, the air gap is fabricated by a method as claimed in claim 13 .

25. The semiconductor structure of claim 24 is used in a resistive memory device.

26. The semiconductor structure of claim 24 is used in a micro electro-mechanical system (MEMS), a nano electro-mechanical system (NEMS), a semiconductor device with copper wires, a radio frequency device or a dynamic random access memory.