Removing metal fills in a wiring layer

1. A semiconductor manufacturing method, comprising:

forming a metal wiring layer on a semiconductor substrate, the metal wiring layer comprising dielectrics and metal wires and metal fills within the dielectrics; and

removing the metal fills in the metal wiring layer completely to form the metal wiring layer without the metal fills, comprises:

removing the dielectrics adjacent to the metal fills in all regions containing the metal fills within the metal wiring layer;

removing the metal fills in the regions containing the metal fills;

filling trenches formed by removing the metal fills and the dielectrics in the regions containing the metal fills with additional dielectrics; and

polishing the additional dielectrics.

2. The method according to claim 1 , further comprising:

annealing the additional dielectrics.

3. The method according to claim 1 , wherein, the metal fills are removed through wet etching, dry etching or a combination thereof.

4. The method according to claim 1 , wherein, the dielectrics and the additional dielectrics comprise SiO 2 and the metal comprises Cu.

5. The method according to claim 1 , wherein, the metal wires and the metal fills comprise core conductors and conductive liner layers, wherein the conductive liner layers locate on side surface and bottom surface of the core conductors.

6. The method according to claim 5 , wherein, the core conductors comprise Cu, and the conductive liner layers comprise Ta or TaN.

7. The method according to claim 5 , wherein, removing the metal fills comprises removing the core conductors and the conductive liner layers simultaneously.

8. The method according to claim 5 , wherein, removing the metal fills comprises removing the core conductors and the conductive liner layers respectively.

9. The method according to claim 1 , wherein, removing the dielectrics and the metal fills comprises:

applying resist on the metal wiring layer;

patterning the resist to form a patterned resist, the patterned resist having openings exposing all regions containing the metal fills within the metal wiring layer;

etching, by using the patterned resist as etch mask, exposed dielectrics of the metal wiring layer while leaving the metal fills, thereby exposing top surfaces and side walls of the metal fills;

etching the metal fills to form trenches in the dielectrics; and

removing the patterned resist.

10. The method according to claim 1 , wherein, the step of removing the metal fills comprises:

applying resist on the metal wiring layer;

patterning the resist to form patterned resist, the patterned resist having openings exposing all regions containing the metal fills within the metal wiring layer;

etching the metal fills to form trenches in the dielectrics; and

removing the patterned resist.

11. The method according to claim 1 , wherein, forming a metal wiring layer comprises:

depositing the dielectrics on the metal wiring layer;

applying resist on the dielectrics;

patterning the resist to form patterned resist, the patterned resist having openings for forming the metal wires and the metal fills within the metal wiring layer;

etching, by using the patterned resist as etching mask, the dielectrics to form trenches for the metal wires and the metal fills in the dielectric layer;

removing the resist;

depositing the metal on top surface of the dielectric layer and in the trenches to fill the trenches; and

polishing the metal to form the metal wiring layer.

12. The method according to claim 1 , wherein, forming a metal wiring layer comprises a first lithography step using a first mask, and removing the metal fills in the metal wiring layer completely comprises a second lithography step using a second mask, wherein the first mask having a first mask pattern for forming the metal wires and the metal fills in the metal wiring layer, and the second mask having a second mask pattern for completely removing the metal fills in the metal wiring layer.