PLASMA ETCHING METHOD AND COMPUTER-READABLE STORAGE MEDIUM

Abstract

A plasma etching method for forming a trench on a substrate or on a film formed on the substrate, includes an substrate arranging step of arranging the substrate on which the trench is to be formed in a processing chamber having therein a first and a second electrode disposed to face each other vertically; a processing gas introducing step of introducing a processing gas for etching into the processing chamber; a plasma generating step of generating a plasma by applying a high frequency electric power to either of the first and the second electrode; and a DC voltage applying step of applying a DC voltage to said either of the electrodes. Further, a computer-readable storage medium stores therein a computer-executable control program, wherein, when the control program is being executed, a computer is made to control a plasma processing apparatus to perform the 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 an embodiment, given in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic cross sectional view of an example of a plasma etching apparatus used for implementing the present invention;

FIG. 2 shows a structure of a matching unit connected to a first high frequency power in the plasma etching apparatus of FIG. 1;

FIG. 3 illustrates a cross sectional view showing a state in which a partial via has been formed by an etching on a semiconductor wafer W in accordance with an embodiment of the present invention;

FIG. 4 presents a cross sectional view illustrating a structure of a semiconductor wafer where a BARC and a photoresist film has been ashed for a trench etching after forming the partial via of FIG. 3;

FIG. 5 represents a cross sectional view illustrating a state in which a trench has been formed by etching an interlayer insulating film in accordance with the embodiment of the present invention;

FIG. 6 describes examples of the intra-surface distribution of etching rate of an oxide film when different DC voltages are applied;

FIG. 7 depicts other example of the intra-surface distribution of etching rate of the oxide film when different DC voltages are applied;

FIG. 8 shows locations on a semiconductor wafer where a trench depth has been measured after performing the trench etching;

FIG. 9 offers a schematic cross sectional view of an example of another plasma etching apparatus that can be employed for implementing the present invention;

FIG. 10 provides a schematic cross sectional view of an example of still another plasma etching apparatus that can be employed for implementing the present invention;

FIG. 11 illustrates a schematic cross sectional view of an example of still another plasma etching apparatus that can be employed for implementing the present invention; and

FIG. 12 depicts a schematic cross sectional view of an example of still another plasma etching apparatus that can be employed for implementing the present invention.

Claims

1. A plasma etching method for forming a trench on a substrate or on a film formed on the substrate, comprising: an substrate arranging step of arranging the substrate on which the trench is to be formed in a processing chamber having therein a first and a second electrode disposed to face each other vertically;a processing gas introducing step of introducing a processing gas for etching into the processing chamber;a plasma generating step of generating a plasma by applying a high frequency electric power to either of the first and the second electrode; anda DC voltage applying step of applying a DC voltage to said either of the electrodes.

2. The plasma etching method of claim 1, wherein the DC voltage is within a range from about −400 V to about −1500 V.

3. The plasma etching method of claim 1, wherein the trench is formed in an interlayer insulating film formed on the substrate.

4. The plasma etching method of claim 2, wherein the trench is formed in an interlayer insulating film formed on the substrate.

5. The plasma etching method of claim 3, wherein the trench is formed after a via is formed in the interlayer insulating film.

6. The plasma etching method of claim 4, wherein the trench is formed after a via is formed in the interlayer insulating film.

7. The plasma etching method of claim 1, wherein a specific DC voltage level for securing a desired intra-surface etching uniformity on a test object is obtained in advance, and the specific DC voltage level is applied to said either of the electrodes in the DC voltage applying step.

8. The plasma etching method of claim 2, wherein a specific DC voltage level for securing a desired intra-surface etching uniformity on a test object is obtained in advance, and the specific DC voltage level is applied to said either of the electrodes in the DC voltage applying step.

9. The plasma etching method of claim 1, wherein the first electrode is an upper electrode, the second electrode is a lower electrode for mounting thereon an object to be processed, and the high frequency electric power for generating the plasma and the DC voltage are applied to the first electrode.

10. The plasma etching method of claim 2, wherein the first electrode is an upper electrode, the second electrode is a lower electrode for mounting thereon an object to be processed, and the high frequency electric power for generating the plasma and the DC voltage are applied to the first electrode.

11. The plasma etching method of claim 7, wherein the first electrode is an upper electrode, the second electrode is a lower electrode for mounting thereon an object to be processed, and the high frequency electric power for generating the plasma and the DC voltage are applied to the first electrode.

12. The plasma etching method of claim 8, wherein the first electrode is an upper electrode, the second electrode is a lower electrode for mounting thereon an object to be processed, and the high frequency electric power for generating the plasma and the DC voltage are applied to the first electrode.

13. The plasma etching method of claim 9, wherein a high frequency electric power for attracting ions is applied to the second electrode.

14. The plasma etching method of claim 10, wherein a high frequency electric power for attracting ions is applied to the second electrode.

15. The plasma etching method of claim 11, wherein a high frequency electric power for attracting ions is applied to the second electrode.

16. The plasma etching method of claim 12, wherein a high frequency electric power for attracting ions is applied to the second electrode.

17. A computer-readable storage medium for storing therein a computer-executable control program, wherein, when the control program is being executed, a computer is made to control a plasma processing apparatus to perform the plasma etching method described in claim 1.

18. A computer-readable storage medium for storing therein a computer-executable control program, wherein, when the control program is being executed, a computer is made to control a plasma processing apparatus to perform the plasma etching method described in claim 2.

19. A computer-readable storage medium for storing therein a computer-executable control program, wherein, when the control program is being executed, a computer is made to control a plasma processing apparatus to perform the plasma etching method described in claim 7.

20. A computer-readable storage medium for storing therein a computer-executable control program, wherein, when the control program is being executed, a computer is made to control a plasma processing apparatus to perform the plasma etching method described in claim 9.