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

Abstract

A plasma etching method includes the step of performing a plasma etching on a silicon-containing dielectric layer formed on a substrate to be processed by using a plasma, while using an organic layer as a mask. In addition, the plasma is generated from a processing gas at least including a first fluorocarbon gas which is an unsaturated gas; a second fluorocarbon gas which is an aliphatic saturated gas expressed by CmF2m+2 (m=5, 6); and an oxygen gas. Further, a computer-readable storage medium for storing therein a computer executable control program is provided where the control program, when executed, controls a plasma etching apparatus to perform the above plasma etching method.

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 diagram to explain definitions of an etching rate and a selectivity at a shoulder portion.

Claims

1. A plasma etching method comprising the step of: performing a plasma etching on a silicon-containing dielectric layer formed on a substrate to be processed by using a plasma, while using an organic layer as a mask, wherein the plasma is generated from a processing gas at least including a first fluorocarbon gas which is an unsaturated gas; a second fluorocarbon gas which is an aliphatic saturated gas expressed by CmF2m+2 (m=5, 6); and an oxygen gas.

2. The plasma etching method of claim 1, wherein the first fluorocarbon gas is C4F6 and the second fluorocarbon gas is C5F12, and a flow rate ratio between the C4F6, the C5F12 and the oxygen gas is about 2:1:2.0 to 2.4.

3. The plasma etching method of claim 1, wherein the first fluorocarbon gas is C4F6 and the second fluorocarbon gas is C6F14, and a flow rate ratio between the C4F6, the C6F14 and the oxygen gas is about 2:1:2.2 to 2.6.

4. The plasma etching method of claim 1, wherein the organic layer is a photoresist layer, and the silicon-containing dielectric layer is a silicon oxide layer.

5. The plasma etching method of claim 1, wherein the processing gas further contains a rare gas.

6. The plasma etching method of claim 5, wherein the rare gas is an argon gas.

7. The plasma etching method of claim 1, wherein the plasma etching is performed, in a processing chamber having a lower electrode for mounting the substrate to be processed thereon and an upper electrode disposed to face the lower electrode, by applying high frequency powers between the upper and the lower electrode.

8. The plasma etching method of claim 7, wherein the high frequency powers include a first high frequency power applied to the upper electrode; and a second high frequency power applied to the lower electrode, wherein a frequency of the second high frequency power is lower than that of the first high frequency power.

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

10. A computer-executable control program, which controls, when executed, a plasma etching apparatus to perform the plasma etching method of claim 1.

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