Cleaning solution, cleaning method and damascene process using the same

1. A cleaning solution, comprising:

(a) 0.01-0.1 wt % of hydrofluoric acid (HF);

(b) 1-5 wt % of a strong acid, wherein the strong acid is an inorganic acid;

(c) 0.05-0.5 wt % of ammonium fluoride (NH 4 F);

(d) a chelating agent containing a carboxylic group;

(e) triethanolamine (TEA);

(f) ethylenediaminetetraacetic acid (EDTA); and

(g) water for balance.

2. The cleaning solution of claim 1 , wherein the strong acid comprises sulfuric acid (H 2 SO 4 ) or hydrochloric acid (HCl).

3. The cleaning solution of claim 1 , wherein the chelating agent containing the carboxylic group comprises oxalic acid.

4. The cleaning solution of claim 1 , which consists of (a) to (g).

5. A damascene process, comprising:

providing a substrate having a conductive layer and a cap layer sequentially thereon;

sequentially forming a dielectric layer and a metal hard mask layer on the cap layer;

sequentially etching the metal hard mask layer, the dielectric layer and the cap layer, so as to form an opening exposing the conductive layer;

performing a post-etch cleaning process with a cleaning solution, the cleaning solution comprising:

(a) 0.01-0.1 wt % of hydrofluoric acid (HF);

(b) 1-5 wt % of a strong acid, wherein the strong acid is an inorganic acid;

(c) 0.05-0.5 wt % of ammonium fluoride (NH 4 F);

(d) a chelating agent containing a carboxylic group;

(e) triethanolamine (TEA);

(f) ethylenediaminetetraacetic acid (EDTA); and

(g) water for balance;

filling a conductive material in the opening; and

removing the metal hard mask layer.

6. The damascene process of claim 5 , wherein the strong acid comprises sulfuric acid (H 2 SO 4 ) or hydrochloric acid (HCl).

7. The damascene process of claim 5 , wherein the chelating agent containing the carboxylic group comprises oxalic acid.

8. The damascene process of claim 5 , wherein the cleaning solution consists of (a) to (g).

9. The damascene process of claim 5 , wherein the opening comprises a dual damascene opening, a via opening or a contact opening.

10. The damascene process of claim 5 , wherein the metal hard mask layer comprises titanium, titanium nitride, tantalum, tantalum nitride, tungsten, tungsten nitride, or a combination thereof.

11. The damascene process of claim 5 , wherein the cap layer comprises silicon nitride, carbide silicon nitride or silicon carbide.

12. The damascene process of claim 5 , wherein the dielectric layer comprises an ultra low-k material.

13. The damascene process of claim 5 , further comprising forming a buffer layer after the step of forming the dielectric layer and before the step of forming the metal hard mask layer, wherein the buffer layer comprises silicon oxide or silicon oxynitride.

14. The damascene process of claim 13 further comprising forming another cap layer after the step of forming the metal hard mask layer, wherein the another cap layer comprises silicon carbide, silicon nitride or oxynitride silicon.

15. A cleaning method, suitable for a semiconductor process with to-be-removed residual species comprising refractory metal, fluorine, oxygen, silicon, carbon and copper, comprising:

performing a first cleaning process with a cleaning solution, the cleaning solution comprising:

(a) 0.01-0.1 wt % of hydrofluoric acid (HF);

(b) 1-5 wt % of a strong acid, wherein the strong acid is an inorganic acid;

(c) 0.05-0.5 wt % of ammonium fluoride (NH 4 F);

(d) a chelating agent containing a carboxylic group;

(e) triethanolamine (TEA);

(f) ethylenediaminetetraacetic acid (EDTA); and

(g) water for balance.

16. The cleaning method of claim 15 , wherein the strong acid comprises sulfuric acid (H 2 SO 4 ) or hydrochloric acid (HCl).

17. The cleaning method of claim 15 , wherein the chelating agent containing the carboxylic group comprises oxalic acid.

18. The cleaning method of claim 15 , wherein the cleaning solution consists of (a) to (g).

19. The cleaning method of claim 15 , further comprising immediately performing a second cleaning process with DI water after the step of performing the first cleaning process.