PLASMA ETCHING METHOD, PLASMA ETCHING APPARATUS, AND COMPUTER-READABLE STORAGE MEDIUM

Abstract

A plasma etching method includes the step of performing a plasma etching on a SiCN layer, which is formed on a substrate to be processed having a SiOCH layer and the SiCN layer, by using a plasma of an etching gas. A gaseous mixture including CF4 and NF3 is employed as the etching gas, and the SiCN layer is selectively etched against the SiOCH layer. In the plasma etching method, a selectivity of the SiCN layer against the SiOCH layer (an etching rate of the SiCN layer/an etching rate of the SiOCH layer) is equal to or greater than about 1.1 and a flow rate ratio of the NF3 to the CF4 is equal to or greater than about 6%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features of the present invention will become apparent from the following description of embodiments given in conjunction with the accompanying drawings, in which:

FIGS. 1A and 1B provide cross sectional views of a semiconductor wafer to which a plasma etching method in accordance with an embodiment of the present invention is applied;

FIG. 2 sets forth a schematic configuration view of a plasma etching apparatus in accordance with the embodiment of the present invention; and

FIG. 3 presents a graph showing a relationship between a NF₃ flow rate and a SiCN/SiOCH selectivity.

Claims

1. A plasma etching method comprising the step of: performing a plasma etching on a SiCN layer, which is formed on a substrate to be processed having a SiOCH layer and the SiCN layer, by using a plasma of an etching gas,wherein a gaseous mixture including CF4 and NF3 is employed as the etching gas, and the SiCN layer is selectively etched against the SiOCH layer.

2. A plasma etching method comprising the step of: performing a plasma etching on a SiCN layer, which is formed on a substrate to be processed having a SiOCH layer provided with a trench and a via hole by using a plasma of an etching gas, the SiCN layer, to be used as an etching stopper layer, being formed under the SiOCH layer,wherein a gaseous mixture including CF4 and NF3 is employed as the etching gas, and the SiCN layer is selectively etched against the SiOCH layer.

3. The plasma etching method of claim 1, wherein a selectivity of the SiCN layer against the SiOCH layer (an etching rate of the SiCN layer/an etching rate of the SiOCH layer) is equal to or greater than about 1.1.

4. The plasma etching method of claim 2, wherein a selectivity of the SiCN layer against the SiOCH layer (an etching rate of the SiCN layer/an etching rate of the SiOCH layer) is equal to or greater than about 1.1.

5. The plasma etching method of claim 1, wherein a flow rate ratio of the NF3 to the CF4 is equal to or greater than about 6%.

6. The plasma etching method of claim 2, wherein a flow rate ratio of the NF3 to the CF4 is equal to or greater than about 6%.

7. The plasma etching method of claim 3, wherein a flow rate ratio of the NF3 to the CF4 is equal to or greater than about 6%.

8. The plasma etching method of claim 4, wherein a flow rate ratio of the NF3 to the CF4 is equal to or greater than about 6%.

9. The plasma etching method of claim 1, wherein the plasma etching is performed by using a plasma etching apparatus including a processing chamber in which a lower electrode for mounting the substrate to be processed thereon and an upper electrode disposed to face the lower electrode, by applying a first high frequency power for plasma generation to the upper or the lower electrode while applying a second high frequency power for ion induction to the lower electrode, wherein a frequency of the second high frequency power is lower than that of the first high frequency power, and the second high frequency power applied to the lower electrode is set to be equal to or lower than about 0.42 W/cm2.

10. The plasma etching method of claim 2, wherein the plasma etching is performed by using a plasma etching apparatus including a processing chamber in which a lower electrode for mounting the substrate to be processed thereon and an upper electrode disposed to face the lower electrode, by applying a first high frequency power for plasma generation to the upper or the lower electrode while applying a second high frequency power for ion induction to the lower electrode, wherein a frequency of the second high frequency power is lower than that of the first high frequency power, and the second high frequency power applied to the lower electrode is set to be equal to or lower than about 0.42 W/cm2.

11. The plasma etching method of claim 3, wherein the plasma etching is performed by using a plasma etching apparatus including a processing chamber in which a lower electrode for mounting the substrate to be processed thereon and an upper electrode disposed to face the lower electrode, by applying a first high frequency power for plasma generation to the upper or the lower electrode while applying a second high frequency power for ion induction to the lower electrode, wherein a frequency of the second high frequency power is lower than that of the first high frequency power, and the second high frequency power applied to the lower electrode is set to be equal to or lower than about 0.42 W/cm2.

12. The plasma etching method of claim 4, wherein the plasma etching is performed by using a plasma etching apparatus including a processing chamber in which a lower electrode for mounting the substrate to be processed thereon and an upper electrode disposed to face the lower electrode, by applying a first high frequency power for plasma generation to the upper or the lower electrode while applying a second high frequency power for ion induction to the lower electrode, wherein a frequency of the second high frequency power is lower than that of the first high frequency power, and the second high frequency power applied to the lower electrode is set to be equal to or lower than about 0.42 W/cm2.

13. The plasma etching method of claim 5, wherein the plasma etching is performed by using a plasma etching apparatus including a processing chamber in which a lower electrode for mounting the substrate to be processed thereon and an upper electrode disposed to face the lower electrode, by applying a first high frequency power for plasma generation to the upper or the lower electrode while applying a second high frequency power for ion induction to the lower electrode, wherein a frequency of the second high frequency power is lower than that of the first high frequency power, and the second high frequency power applied to the lower electrode is set to be equal to or lower than about 0.42 W/cm2.

14. The plasma etching method of claim 6, wherein the plasma etching is performed by using a plasma etching apparatus including a processing chamber in which a lower electrode for mounting the substrate to be processed thereon and an upper electrode disposed to face the lower electrode, by applying a first high frequency power for plasma generation to the upper or the lower electrode while applying a second high frequency power for ion induction to the lower electrode, wherein a frequency of the second high frequency power is lower than that of the first high frequency power, and the second high frequency power applied to the lower electrode is set to be equal to or lower than about 0.42 W/cm2.

15. The plasma etching method of claim 7, wherein the plasma etching is performed by using a plasma etching apparatus including a processing chamber in which a lower electrode for mounting the substrate to be processed thereon and an upper electrode disposed to face the lower electrode, by applying a first high frequency power for plasma generation to the upper or the lower electrode while applying a second high frequency power for ion induction to the lower electrode, wherein a frequency of the second high frequency power is lower than that of the first high frequency power, and the second high frequency power applied to the lower electrode is set to be equal to or lower than about 0.42 W/cm2.

16. The plasma etching method of claim 8, wherein the plasma etching is performed by using a plasma etching apparatus including a processing chamber in which a lower electrode for mounting the substrate to be processed thereon and an upper electrode disposed to face the lower electrode, by applying a first high frequency power for plasma generation to the upper or the lower electrode while applying a second high frequency power for ion induction to the lower electrode, wherein a frequency of the second high frequency power is lower than that of the first high frequency power, and the second high frequency power applied to the lower electrode is set to be equal to or lower than about 0.42 W/cm2.

17. A plasma etching apparatus comprising: a processing chamber for accommodating therein a semiconductor substrate to be processed;a processing gas supply unit for supplying an etching gas into the processing chamber;a plasma generating unit for converting the etching gas supplied from the processing gas supply unit into a plasma, thereby plasma processing the semiconductor substrate; anda control unit for controlling the plasma etching method of claim 1 to be carried out in the processing chamber.

18. A plasma etching apparatus comprising: a processing chamber for accommodating therein a semiconductor substrate to be processed;a processing gas supply unit for supplying an etching gas into the processing chamber;a plasma generating unit for converting the etching gas supplied from the processing gas supply unit into a plasma, thereby plasma processing the semiconductor substrate; anda control unit for controlling the plasma etching method of claim 2 to be carried out in the processing chamber.

19. A computer-readable storage medium for storing therein a computer executable control program, wherein the control program controls the plasma processing apparatus to perform the plasma etching method of claim 1.

20. A computer-readable storage medium for storing therein a computer executable control program, wherein the control program controls the plasma processing apparatus to perform the plasma etching method of claim 2.