PLASMA ETCHING APPARATUS AND METHOD

Abstract

A plasma etching apparatus includes an evacuable processing chamber for performing a plasma etching process on a target object; a mounting table for mounting thereon the target object in the processing chamber; and a shower head facing the mounting table, for introducing a processing gas for generating a plasma to the processing chamber. Further, the apparatus includes a ring-shaped protrusion protruded from a bottom surface of the shower head toward the mounting table; and a plurality of gas introducing openings inclusively arranged in an area smaller than the target object in an inner central portion of the ring-shaped protrusion on the bottom surface of the shower head.

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 preferred embodiments, given in conjunction with the accompanying drawings, in which:

FIG. 1 shows a cross sectional view of a magnetron RIE plasma etching apparatus suitable for performing an etching method of the present invention;

FIG. 2 describes a schematic horizontal cross sectional view of a dipole ring magnet unit arranged around an outer periphery of a chamber of the apparatus of FIG. 1;

FIG. 3 provides a schematic diagram to explain an electric field and a magnetic field formed in the chamber;

FIG. 4 presents a diagram to explain an arrangement of a ring-shaped protrusion and gas introducing openings;

FIG. 5 shows a top view of a bottom surface of a shower head to explain the arrangement of the ring-shaped protrusion and the gas introducing openings;

FIG. 6 represents a schematic cross sectional view showing a vicinity of a surface of a semiconductor wafer being plasma etched; and

FIG. 7 illustrates a schematic cross sectional view showing a vicinity of a surface of a plasma etched semiconductor wafer.

Claims

1. A plasma etching apparatus comprising: an evacuable processing chamber for performing a plasma etching process on a target object;a mounting table for mounting thereon the target object in the processing chamber;a shower head facing the mounting table, for introducing a processing gas for generating a plasma to the processing chamber;a ring-shaped protrusion protruded from a bottom surface of the shower head toward the mounting table; anda plurality of gas introducing openings inclusively arranged in an area smaller than the target object in an inner central portion of the ring-shaped protrusion on the bottom surface of the shower head.

2. The plasma etching apparatus of claim 1, wherein the mounting table and the shower head function as a lower and an upper electrode, respectively, to form a pair of facing electrodes.

3. The plasma etching apparatus of claim 1, wherein an outer diameter of the ring-shaped protrusion is about 1.1 to about 1.5 times a diameter L of the target object.

4. The plasma etching apparatus of claim 3, wherein an inner diameter of the ring-shaped protrusion is greater than the diameter L of the target object.

5. The plasma etching apparatus of claim 1, wherein a height of the ring-shaped protrusion is equal to or greater than about 0.4 times a distance from the mounting table to the shower head.

6. The plasma etching apparatus of claim 1, wherein the gas introducing openings are inclusively formed in an area of about 0.3 L×0.3 L to about 0.7 L×0.7 L, L being a diameter of the target object.

7. A plasma etching method for performing, by using the plasma etching apparatus described in claim 1, a plasma etching process on the target object having an etching target layer mainly made of silicon and a pre-patterned resist layer formed above the etching target layer by applying a plasma generated from a processing gas containing SF6 and O2 to the etching target layer while using the resist layer as a mask.

8. The plasma etching method of claim 7, wherein the etching target layer is a silicon substrate or a silicon layer.

9. A computer-executable control program, which controls, when executed, the plasma etching apparatus such that the plasma etching method described in claim 7 is performed.

10. A computer readable storage medium that stores therein a computer-executable control program, wherein the control program controls the plasma etching apparatus such that the plasma etching method described in claim 7 is performed.