Method for manufacturing a semiconductor device

1. A method for manufacturing a semiconductor device, comprising:

forming an etch stop layer on the semiconductor substrate;

sequentially forming a first interlayer insulating layer, a first diffusion barrier, a second interlayer insulating layer, and a second diffusion barrier on the etch stop layer;

forming a via hole exposing the etch stop layer by etching the second diffusion barrier, the second interlayer insulating layer, the first diffusion barrier, and the first interlayer insulating layer;

forming a first trench overlapping the via hole by etching the second diffusion barrier and the second interlayer insulating layer;

forming a second trench continuous to the first trench by etching the first diffusion barrier and part of the first interlayer insulating layer; and

removing the etch stop layer exposed through the via hole,

wherein the first and second trenches are etched under different etching conditions.

2. The method of claim 1 , further comprising, after removing the etch stop layer, forming a metal line filling the via hole and the trench.

3. The method of claim 2 , wherein:

the semiconductor substrate further comprises a lower metal line; and

the metal line filling the via hole and the trench connects to the lower metal line through the via hole.

4. The method of claim 1 , wherein forming the first wench comprises dry etching with an etching gas comprising CHF 3 at a flow rate of 20-80 sccm, O 2 at a flow rate of 10-20 sccm, and Ar at a flow rate of 400-600 sccm.

5. The method of claim 4 , wherein forming the first trench further comprises dry etching at a pressure of 50-100 mTorr, a source power of 1,000-2,000 W, and a bias power of 1,400-2,000 W.

6. The method of claim 4 , wherein forming the second trench comprises dry etching with an etching gas comprising C 5 F 8 at a flow rate of 10-30 sccm, O 2 at a flow rate of 10-20 sccm, and Ar at a flow rate of 600-800 sccm, at a pressure of 50-150 mTorr, a source power of 500-1,000 W, and a bias power of 1,000-2,000 W.

7. The method of claim 1 , wherein forming the second trench comprises day etching with an etching gas comprising C 5 F 8 at a flow rate of 10-30 sccm, O 2 at a flow rate of 10-20 sccm, and Ar at a flow rate of 600-800 sccm.

8. The method of claim 7 , wherein forming the second trench further comprises day etching at a pressure of 50-150 mTorr, a source power of 500-1,000 W, and a bias power of 1,000-2,000 W.

9. The method of claim 1 , wherein:

the etch stop layer comprises a P—SiH 4 oxide layer.

10. The method of claim 1 , wherein:

the first and second diffusion barriers each comprise a P—SiH 4 oxide layer; and

the first and second interlayer insulating layers each comprise a fluorinated silica glass (FSG).

11. The method of claim 1 , wherein the etch stop layer has a thickness of 200-400 Å, the first interlayer insulating layer has a thickness of 4,000-6,000 Å, the first diffusion barrier has a thickness of 500-1,000 Å, the second interlayer insulating layer bas a thickness of 3,000-5,000 Å, and the second diffusion barrier has a thickness of 200-500 Å.

12. A method for manufacturing a semiconductor device, comprising:

forming an etch stop layer on a semiconductor substrate;

sequentially forming a first interlayer insulating layer, a first diffusion barrier, a second interlayer insulating layer, and a second diffusion barrier on the etch stop layer;

forming a via hole exposing the etch stop layer by etching the second diffusion barrier, the second interlayer insulating layer, the first diffusion barrier, and the first interlayer insulating layer at an etching chamber pressure of 50-100 mTorr, a source power of 1,000-2,000 W, and a bias power of 1,400-2,000 W;

forming a trench overlapping the via hole by etching the second diffusion barrier and the second interlayer insulating layer with an etching gas including CHF 3 at a flow rate of 20-80 sccm, O 2 at a flow rate of 10-20 sccm, and Ar at a flow rate of 400-600 sccm; and

removing the etch stop layer exposed through the via hole.

13. The method of claim 12 , wherein the first and second diffusion barriers comprise a P—SiH 4 oxide layer.

14. The method of claim 12 , wherein the etch stop layer comprises a P—SiH 4 oxide layer.

15. A method for manufacturing a semiconductor device, comprising:

forming a via hole through first and second diffusion barriers and upper and lower insulating layers, the via hole exposing an underlying etch stop layer;

etching the second diffusion baffler and the upper insulating layer under first etching conditions to form a trench having a first depth, the wench overlapping the via hole;

etching the first diffusion barrier and the lower insulating layer under second etching conditions to extend the trench to a second depth, the second etching conditions differing from the first etching conditions; and

removing the etch stop layer exposed through the via hole.

16. The method of claim 15 , wherein the etch stop layer and the first and second diffusion barriers each comprise a P—SiH 4 oxide layer, and the lower and upper insulating layers each comprise a fluorinated silica glass (FSG).

17. The method of claim 16 , wherein the etch stop layer has a thickness of 200-400 Å, the lower insulating layer has a thickness of 4,000-6,000 Å, the first diffusion barrier has a thickness of 500-1,000 Å, the upper insulating layer has a thickness of 3,000-5,000 Å, and the second diffusion barrier has a thickness of 200-500 Å.

18. The method of claim 15 , wherein:

forming the trench comprises dry etching with an etching gas comprising a hydrofluorocarbon and a first oxygen source at a pressure, a source power, and a bias power sufficient to form the Wench at the first depth; and

extending the wench to the second depth comprises dry etching with an etching gas comprising a fluorocarbon and a second oxygen source at a pressure, a source power, and a bias power sufficient to provide a plurality of wenches across the semiconductor device with predefined dimensions.

19. The method of claim 18 , wherein:

forming the trench comprises dry etching with an etching gas comprising CHF 3 , at a flow rate of 20-80 sccm, O 2 at a flow rate of 10-20 sccm, and Ar at a flow rate of 400-600 sccm; and

extending the trench to the second depth comprises dry etching with an etching gas comprising C 5 F 8 at a flow rate of 10-30 sccm, O 2 at a flow rate of 10-20 sccm, and Ar at a flow rate of 600-800 sccm.