Hybrid plasma reactor

Abstract

Provided is a hybrid plasma reactor. The hybrid plasma reactor includes an ICP (Inductively Coupled Plasma) source unit and a bias RF (Radio Frequency) power supply unit. The ICP source unit includes a chamber, an antenna coil unit, and a source power supply unit. The chamber includes a chamber body whose top is opened and a dielectric window covering the opened top of the chamber body. The antenna coil unit is disposed outside of the dielectric window. The source power supply unit supplies a source power to the antenna coil unit. The bias RF power supply unit supplies a bias RF power to a cathode. The cathode is installed within the chamber and mounts a target wafer on its top.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to aid in The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a construction of a plasma reactor according to a first exemplary embodiment of the present invention;

FIG. 2 illustrates a cross-sectional diagram of an antenna coil unit shown in FIG. 1, and a distribution of magnetic field generated around the antenna coil unit when a source power is supplied to the antenna coil unit;

FIG. 3 is a graph illustrating an intensity of magnetic field depending on each radius (R) of a primary antenna coil group and a secondary antenna coil group included in the antenna coil unit shown in FIG. 2 and a length (L) between the primary and secondary antenna coil groups;

FIG. 4 is a flowchart illustrating an etch procedure implemented by the plasma reactor shown in FIG. 1;

FIG. 5 illustrates a construction of a plasma reactor according to a second exemplary embodiment of the present invention;

FIG. 6 is a flowchart illustrating an etch procedure implemented by the plasma reactor shown in FIG. 5;

FIG. 7 illustrates a construction of a plasma reactor according to a third exemplary embodiment of the present invention;

FIG. 8 is a flowchart illustrating an etch procedure implemented by the plasma reactor shown in FIG. 7;

FIG. 9 is a graph illustrating a plasma ion density characteristic depending on an increase of a source power;

FIG. 10 is a graph illustrating variation of a self-bias (−VDC) formed in a cathode versus variation of a source power when a bias RF power of 2 MHz is supplied to the cathode of a plasma reactor according to the present invention;

FIG. 11 is a graph illustrating variation of a self-bias (−VDC) formed in a cathode versus variation of a source power when a bias RF power of 12.56 MHz is supplied to the cathode of a plasma reactor according to the present invention;

FIG. 12 is a graph illustrating variation of a self-bias (−VDC) formed in a cathode versus variation of a source power when a bias RF power of 27.12 MHz is supplied to the cathode of a plasma reactor according to the present invention;

FIG. 13 is a graph illustrating variation of a self-bias (−VDC) formed in a cathode versus variation of a source power, in each case where a single frequency bias RF power is supplied and a mixed frequency bias RF power is supplied to the cathode of a plasma reactor according to the present invention;

FIG. 14 is a graph illustrating variation of an etch rate versus variation of a frequency mixture rate of a bias RF power supplied to a cathode, when a source power of 600 W is supplied to an antenna coil unit of a plasma reactor according to the present invention; and

FIG. 15 is a graph illustrating variation of an etch rate versus variation of a frequency mixture rate of a bias RF power supplied to a cathode, when a source power of 1500 W is supplied to an antenna coil unit of a plasma reactor according to the present invention.

Claims

1. A hybrid plasma reactor comprising: an ICP (Inductively Coupled Plasma) source unit comprising: a chamber comprising a chamber body whose top is opened and a dielectric window covering the opened top of the chamber body;an antenna coil unit disposed outside of the dielectric window; anda source power supply unit for supplying a source power to the antenna coil unit; anda bias RF (Radio Frequency) power supply unit for supplying a bias RF power to a cathode, the cathode being installed within the chamber and mounting a target wafer on its top,wherein a plasma ion density within the chamber is greater when a source power greater than a set power is supplied to the antenna coil unit than when a source power smaller than the set power is supplied to the antenna coil unit,wherein a plasma ion energy within the chamber is greater when the source power smaller than the set power is supplied to the antenna coil unit than when the source power greater than the set power is supplied to the antenna coil unit, andwherein in order to increase the set power and expand a tunable range of the source power, the bias RF power supply unit supplies the bias RF power, which is a mixture of a high frequency RF power and a low frequency RF power, to the cathode so that a sudden reduction of the plasma ion energy within the chamber occurring as the source power supplied to the antenna coil unit increases greater than the set power is compensated or so that the plasma ion density and energy within the chamber is sustained within a set range.

2. The reactor of claim 1, wherein there are provided an etch process in a low dissociation region and an etch process in a high dissociation region, depending on a degree of dissociation of a reaction gas injected into the chamber, and wherein the plasma reactor performs the etch process in the low dissociation region when the source power smaller than the set power is supplied to the antenna coil unit, and performs the etch process in the high dissociation region when the source power greater than the set power is supplied to the antenna coil unit.

3. The reactor of claim 1, wherein the bias RF power supply unit comprises: a high frequency RF power supply unit for supplying the high frequency RF power to the cathode; anda low frequency RF power supply unit connecting to the cathode in parallel with the high frequency RF power supply unit, and supplying the low frequency RF power to the cathode,wherein the bias RF power, which is the mixture of the high frequency RF power and the low frequency RF power, is supplied to the cathode when the high frequency RF power supply unit and the low frequency RF power supply unit operate together.

4. The reactor of claim 1, wherein the set power is within a range of 500 W to 700 W when the plasma reactor performs an etch process for a wafer having a diameter of 200 mm.

5. The reactor of claim 1, wherein when the plasma reactor performs an in-situ chamber cleaning operation, the source power supply unit supplies the source power to the antenna coil unit, and the bias RF power supply unit stops supplying the bias RF power to the cathode, and the plasma reactor performs a high density plasma chamber cleaning process with the wafer not mounted on the cathode.

6. The reactor of claim 1, wherein the source power supply unit generates the high frequency RF power as the source power, wherein the bias RF power supply unit comprises:a low frequency RF power supply unit for supplying the low frequency RF power to the cathode; anda source power switch unit connecting to the cathode in parallel with the low frequency RF power supply unit,wherein the source power switch unit switches on to selectively connect the cathode to the ground via the source power switch unit so that the high frequency RF power generated from the source power supply unit is selectively supplied to the cathode,wherein a closed loop is formed comprising the source power supply unit, the antenna coil unit, the cathode, the source power switch unit, and the ground when the cathode connects to the ground via the source power switch unit, andwherein the bias RF power that is the mixture of the high frequency RF power and the low frequency RF power is supplied to the cathode when the cathode connects to the ground via the source power switch unit and the low frequency RF power supply unit operates.

7. The reactor of claim 1, wherein the source power supply unit generates the low frequency RF power as the source power, wherein the bias RF power supply unit comprises:a high frequency RF power supply unit for supplying the high frequency RF power to the cathode; anda source power switch unit connecting to the cathode in parallel with the high frequency RF power supply unit,wherein the source power switch unit switches on to selectively connect the cathode to the ground via the source power switch unit so that the low frequency RF power generated from the source power supply unit is selectively supplied to the cathode,wherein a closed loop is formed comprising the source power supply unit, the antenna coil unit, the cathode, the source power switch unit, and the ground when the cathode connects to the ground via the source power switch unit, andwherein the bias RF power that is the mixture of the high frequency RF power and the low frequency RF power is supplied to the cathode when the cathode connects to the ground via the source power switch unit and the high frequency RF power supply unit operates.

8. The reactor of claim 1, wherein the bias RF power supply unit comprises: a high frequency RF power supply unit for supplying the high frequency RF power to the cathode;a low frequency RF power supply unit connecting to the cathode in parallel with the high frequency RF power supply unit, and supplying the low frequency RF power to the cathode; anda source power switch unit connecting to the cathode in parallel with the high frequency RF power supply unit,wherein the source power switch unit switches on to connect the cathode to the ground via the source power switch unit so that the source power generated from the source power supply unit is selectively supplied to the cathode, andwherein a closed loop is formed comprising the source power supply unit, the antenna coil unit, the cathode, the source power switch unit, and the ground when the cathode connects to the ground via the source power switch unit.

9. The reactor of claim 8, wherein the source power supply unit generates as the source power an additional RF power having a frequency lower than that of the low frequency RF power, wherein the bias RF power supply unit generates the bias RF power obtained by additionally mixing the additional RF power with the high frequency RF power and the low frequency RF power, andwherein the bias RF power obtained by mixing the additional RF power with the high frequency RF power and the low frequency RF power is supplied to the cathode, when the cathode connects to the ground via the source power switch unit and the high frequency RF power supply unit and the low frequency RF power supply unit operate.

10. The reactor of claim 8, wherein the source power supply unit generates as the source power an additional RF power having a frequency than that of the low frequency RF power and lower than that of the high frequency RF power, wherein the bias RF power supply unit generates the bias RF power obtained by additionally mixing the additional RF power with the high frequency RF power and the low frequency RF power, andwherein the bias RF power obtained by mixing the additional RF power with the high frequency RF power and the low frequency RF power is supplied to the cathode, when the cathode connects to the ground via the source power switch unit and the high frequency RF power supply unit and the low frequency RF power supply unit operate.

11. The reactor of claim 8, wherein the source power supply unit generates as the source power an additional RF power having a frequency higher than that of the high frequency RF power, wherein the bias RF power supply unit generates the bias RF power obtained by additionally mixing the additional RF power with the high frequency RF power and the low frequency RF power, andwherein the bias RF power obtained by mixing the additional RF power with the high frequency RF power and the low frequency RF power is supplied to the cathode, when the cathode connects to the ground via the source power switch unit and the high frequency RF power supply unit and the low frequency RF power supply unit operate.

12. A hybrid plasma reactor comprising: an ICP source unit comprising: a chamber comprising a chamber body whose top is opened and a dielectric window covering the opened top of the chamber body;an antenna coil unit disposed outside of the dielectric window; anda source power supply unit for supplying a source power to the antenna coil unit;a high frequency RF power supply unit for supplying a bias RF power to a cathode, the cathode being installed within the chamber and mounting a target wafer on its top; anda low frequency RF power supply unit connecting to the cathode in parallel with the high frequency RF power supply-unit, and supplying a low frequency RF power to the cathode,wherein a plasma ion density within the chamber is greater when a source power greater than a set power is supplied to the antenna coil unit than when a source power smaller than the set power is supplied to the antenna coil unit,wherein a plasma ion energy within the chamber is greater when the source power smaller than the set power is supplied to the antenna coil unit than when the source power greater than the set power is supplied to the antenna coil unit, andwherein in order to increase the set power and expand a tunable range of the source power, the high frequency RF power supply unit and the low frequency RF power supply unit operate together and supply a bias RF power, which is a mixture of the high frequency RF power and the low frequency RF power, to the cathode so that a sudden reduction of the plasma ion energy within the chamber occurring as the source power supplied to the antenna coil unit increases greater than the set power is compensated or so that the plasma ion density and energy within the chamber is sustained within a set range.

13. The reactor of claim 12, wherein there are provided an etch process in a low dissociation region and an etch process in a high dissociation region, depending on a degree of dissociation of a reaction gas injected into the chamber, and wherein the plasma reactor performs the etch process in the low dissociation region when the source power smaller than the set power is supplied to the antenna coil unit, and performs the etch process in the high dissociation region when the source power greater than the set power is supplied to the antenna coil unit.

14. The reactor of claim 12, wherein the set power is within a range of 500 W to 700 W when the plasma reactor performs an etch process for a wafer having a diameter of 200 mm.

15. The reactor of claim 12, wherein when the plasma reactor performs an in-situ chamber cleaning operation, the source power supply unit supplies the source power to the antenna coil unit, and the high frequency RF power supply unit and the low frequency RF power supply unit stop supplying the bias RF power to the cathode, and the plasma reactor performs a high density plasma chamber cleaning process with the wafer not mounted on the cathode.

16. A hybrid plasma reactor comprising: an ICP source unit comprising: a chamber comprising a chamber body whose top is opened and a dielectric window covering the opened top of the chamber body;an antenna coil unit disposed outside of the dielectric window; anda source power supply unit for supplying a source power to the antenna coil unit;a high frequency RF power supply unit for supplying a bias RF power to a cathode, the cathode being installed within the chamber and mounting a target wafer on its top;a low frequency RF power supply unit connecting to the cathode in parallel with the high frequency RF power supply unit, and supplying a low frequency RF power to the cathode; anda source power switch unit connecting to the cathode in parallel with the high frequency RF power supply unit,wherein the source power switch unit switches on to selectively connect the cathode to the ground via the source power switch unit so that the high frequency RF power generated from the source power supply unit is selectively supplied to the cathode,wherein a closed loop is formed comprising the source power supply unit, the antenna coil unit, the cathode, the source power switch unit, and the ground when the cathode connects to the ground via the source power switch unit,wherein the source power is any one of an RF power having a frequency higher than that of the high frequency RF power, an RF power having a frequency lower than that of the low frequency RF power, and an RF power having a frequency between frequencies of the low frequency RF power and the high frequency RF power,wherein a plasma ion density within the chamber is greater when a source power greater than a set power is supplied to the antenna coil unit than when a source power smaller than the set power is supplied to the antenna coil unit,wherein a plasma ion energy within the chamber is greater when the source power smaller than the set power is supplied to the antenna coil unit than when the source power greater than the set power is supplied to the antenna coil unit, andwherein in order to increase the set power and expand a tunable range of the source power, the high frequency RF power supply unit, the low frequency RF power supply unit, and the source power switch unit operate together and supply a bias RF power obtained by mixing the high frequency RF power and the low frequency RF power with the source power, to the cathode so that a sudden reduction of the plasma ion energy within the chamber occurring as the source power supplied to the antenna coil unit increases greater than the set power is compensated or so that the plasma ion density and energy within the chamber is sustained within a set range.

17. The reactor of claim 16, wherein there are provided an etch process in a low dissociation region and an etch process in a high dissociation region, depending on a degree of dissociation of a reaction gas injected into the chamber, and wherein the plasma reactor performs the etch process in the low dissociation region when the source power smaller than the set power is supplied to the antenna coil unit, and performs the etch process in the high dissociation region when the source power greater than the set power is supplied to the antenna coil unit.

18. The reactor of claim 16, wherein the set power is within a range of 500 W to 700 W when the plasma reactor performs an etch process for a wafer having a diameter of 200 mm.

19. The reactor of claim 16, wherein when the plasma reactor performs an in-situ chamber cleaning operation, the source power supply unit supplies the source power to the antenna coil unit, and the high frequency RF power supply unit and the low frequency RF power supply unit stop supplying the bias RF power to the cathode, and the source power switch unit switches off, and the plasma reactor performs a high density plasma chamber cleaning process with the wafer not mounted on the cathode.

20. The reactor of claim 16, wherein the source power switch unit comprises: a source power filter for filtering the source power received from the antenna coil through the cathode, except signals of frequencies other than a frequency of the source power; anda switch for electrically connecting or disconnecting the source power filter from the ground.