Method of making a semiconductor device using a bottom antireflective coating (BARC) layer

1. A method of forming a semiconductor device comprising:

forming an inter-level dielectric (ILD) layer over a substrate;

forming a layer set over the ILD layer, wherein the layer set comprises a plurality of layers;

forming a bottom antireflective coating (BARC) layer over the layer set;

etching the layer set to form a tapered opening in the layer set, wherein etching the layer set comprises etching at least one layer comprising a silicon-rich photoresist material layer and a second material layer different from the silicon-rich photoresist material; and

etching the ILD layer using the layer set as a mask to form an opening in the ILD layer, wherein etching the layer set comprises forming the tapered opening having sidewalls at an angle with respect to a top surface of the ILD layer, and etching the ILD layer comprises reducing a thickness of the layer set.

2. The method of claim 1 , wherein the etching the layer set comprises using carbonyl sulfide (COS).

3. The method of claim 2 , wherein the etching the layer set comprises supplying COS at a flow rate of 5 standard cubic centimeters per minute (sccm) to 50 sccm.

4. The method of claim 1 , wherein the opening in the ILD layer has a line width roughness (LWR) of less than 3 nanometers (nm).

5. The method of claim 1 , wherein the etching the ILD layer comprises a two step etching process comprising:

etching a top portion of the ILD layer with a first etchant; and

etching a bottom portion of the ILD layer with a second etchant different than the first etchant.

6. The method of claim 5 , wherein the two step etching process comprises using the first etchant comprising tetrafluoromethane (CF4) and the second etchant comprising hexa-fluoro-butadiene (C4F6).

7. The method of claim 1 , wherein etching the second material layer comprises etching a carbon-rich organic material layer.

8. The method of claim 1 , wherein reducing the thickness of the layer set comprises removing at least one layer of the plurality of layers.

9. The method of claim 1 , wherein etching the layer set comprises reducing a thickness of the BARC layer.

10. A method of making a semiconductor device comprising:

forming an inter-level dielectric (ILD) layer over a substrate;

forming a layer set over the ILD layer, wherein the layer set comprises a plurality of layers;

forming a bottom anti-reflective coating (BARC) layer over the layer set;

forming a photoresist layer over the BARC layer;

forming an opening in the photoresist layer;

etching the BARC layer using the photoresist layer as a mask to form an opening in the BARC layer;

etching the layer set using the BARC layer as a mask to form a tapered opening in the layer set, wherein etching the layer set comprises etching at least one layer comprising a silicon-rich photoresist material layer and a second material layer different from the silicon-rich photoresist material; and

etching the ILD layer using the layer set as a mask to form an opening in the ILD layer, wherein etching the layer set comprises forming the tapered opening having an opening in a top surface of the layer set having a first width and an opening in a bottom surface of the layer set having a second width, and etching the ILD layer comprises substantially removing at least one layer of the plurality of layers.

11. The method of claim 10 , wherein the etching the layer set comprises using carbonyl sulfide (COS).

12. The method of claim 11 , wherein the etching the layer set comprises supplying COS at a flow rate of 5 standard cubic centimeters per minute (sccm) to 50 sccm.

13. The method of claim 10 , wherein the opening in the ILD layer has a line width roughness (LWR) of less than 3 nanometers (nm).

14. The method of claim 10 , wherein the etching the ILD layer comprises a two step etching process comprising:

etching a top portion of the ILD layer with a first etchant; and

etching a bottom portion of the ILD layer with a second etchant different than the first etchant.

15. The method of claim 14 , wherein the two step etching process comprises using the first etchant comprising tetrafluoromethane (CF4) and the second etchant comprising hexa-fluoro-butadiene (C4F6).

16. The method of claim 10 , wherein etching the second material layer comprises etching a carbon-rich organic material layer.

17. The method of claim 10 , further comprising performing an ashing process to remove at least a portion of the layer set.

18. The method of claim 10 , wherein the forming the opening in the photoresist layer comprises performing a photolithography process using a light source having an extreme ultraviolet (EUV) wavelength.

19. The method of claim 10 , wherein etching the layer set comprises forming the tapered opening having sidewalls at an angle with respect to a top surface of the ILD layer ranging from about 85-degrees to about 90-degrees, but less than 90-degrees.

20. A method of making a semiconductor device comprising:

forming an intermediate semiconductor device, the intermediate semiconductor device comprising:

an inter-layer dielectric (ILD) layer;

a layer set over the ILD layer, wherein the layer set comprises:

a silicon-rich photoresist material layer, and

a carbon-rich organic material layer;

a bottom antireflective coating (BARC) layer over the layer set; and

a photoresist layer over the BARC layer;

etching the layer set to form a tapered opening in the layer set, the tapered opening having sidewalls at an angle with respect to a top surface of the ILD layer, wherein etching the layer set comprises substantially removing the BARC layer; and

etching the ILD layer using the layer set as a mask to form an opening in the ILD layer.