Semiconductor device having wirings formed by damascene and its manufacture method

1. A method of manufacturing a semiconductor device comprising:

(a) forming an interlayer insulating film over a semiconductor substrate;

(b) forming a via hole in the interlayer insulating film, the via hole reaching a bottom of the interlayer insulating film;

(c1) forming a filling member over the interlayer insulating film, the via hole being filled with the filling member;

(c2) forming a first hard mask over the filling member, the first hard mask having an opening corresponding to a wiring trench;

(c3) etching the filling member using the first hard mask as an etching mask, the filling member remaining in a lower partial space in the via hole;

after (c3) etching, (c4) removing the first hard mask to expose the filling member formed over the interlayer insulating film;

after (c4) removing, (d) forming a wiring trench continuous with the via hole as viewed in plan, the wiring trench reaching partway in a thickness direction of the interlayer insulating film, the wiring trench being formed under a condition that an etching rate of the interlayer insulating film is faster than an etching rate of the filling member, in such a manner that a height difference after the (d) forming the wiring trench between an upper surface of the filling member left in the via hole and a bottom of the wiring trench is half or less than half a cross-sectional distance of the via hole;

after (d) forming, (e) removing the filling member in the via hole; and

after (e) removing, (f) filling an inside of the via hole and the wiring trench with a conductive member.

2. The method of manufacturing the semiconductor device according to claim 1 , wherein the (f) filling includes covering inner surfaces of the via hole and the wiring trench with a barrier metal film.

3. The method of manufacturing the semiconductor device according to claim 2 , wherein the covering with the barrier metal film comprises:

depositing material of the barrier metal film by sputtering on the inner surfaces of the via hole and the wiring trench; and

re-sputtering the barrier metal film under a condition that an etching rate is faster than a depositing rate.

4. The method of manufacturing the semiconductor device according to claim 1 , wherein the (b) forming the via hole comprises:

(b1) forming a second hard mask over the interlayer insulating film, the second hard mask including material having a different etching resistance from an etching resistance of the interlayer insulating film; and

(b2) forming the via hole extending from an upper surface of the second hard mask to a bottom of the interlayer insulating film.

5. The method of manufacturing the semiconductor device according to claim 4 , wherein

the filling member is made of material having a different etching resistance from etching resistances of the interlayer insulating film and the second hard mask;

the first hard mask includes material having a different etching resistance from an etching resistance of the filling member;

in the (c1) forming, the filling member is deposited on the second hard mask; and

the (c4 ) removing further comprises removing the second hard mask in a region corresponding to the opening formed in the first hard mask.

6. The method of manufacturing the semiconductor device according to claim 5 , wherein in the (d) forming the wire trench, the interlayer insulating film is etched partway in a thickness direction by using as an etching mask the filling member left in the via hole and the filling member left on the second hard mask.

7. The method of manufacturing the semiconductor device according to claim 1 , wherein the interlayer insulating film includes a single material.

8. The method of manufacturing the semiconductor device according to claim 1 , wherein an upper surface of the filling member before the (d) forming the wiring trench is lower than an upper surface of the interlayer insulating film before the (d) forming the wiring trench, and higher than the bottom of the wiring trench after the (d) forming the wiring trench.

9. The method of manufacturing the semiconductor device according to claim 1 , wherein in (d) forming, the filling member in the via hole and the filling member over the interlayer insulating film are etched during forming the wiring trench.

10. The method of manufacturing the semiconductor device according to claim 1 , wherein in (d) forming, the wiring trench is formed by etching the interlayer insulating film using the filling member over the interlayer insulating film as an etching mask.