Plasma tuning rods in microwave processing systems

• US 8,808,496 B2
• Filed: 09/30/2011
• Issued: 08/19/2014
• Est. Priority Date: 09/30/2011
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Zhao, Jianping, Chen, Lee, Funk, Merritt, Iwao, Toshihiko, Ventzek, Peter L. G.
• Primary Examiner(s): DHINGRA, RAKESH KUMAR
• Application Number:
  US13/249,485
• Publication Number:
  US 20130081762A1
• Time in Patent Office: 1,054 Days
• Field of Search: 156/345.35, 156/345.36, 156/345.41, 118/723.MW, 118/723.R, 118/723.ME
• US Class Current: 156/345.41
• CPC Class Codes: H01J 37/32192 Microwave generated discharge H01J37/32357, H01J37/32366, H01J37/32394, H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32247 Resonators
• CPC Class Codes: H01J 37/32256 Tuning means
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

The invention provides a plurality of plasma tuning rod subsystems. The plasma tuning rod subsystems can comprise one or more microwave cavities configured to couple electromagnetic (EM) energy in a desired EM wave mode to a plasma by generating resonant microwave energy in one or more plasma tuning rods within and/or adjacent to the plasma. One or more microwave cavity assemblies can be coupled to a process chamber, and can comprise one or more tuning spaces/cavities. Each tuning space/cavity can have one or more plasma tuning rods coupled thereto. Some of the plasma tuning rods can be configured to couple the EM energy from one or more of the resonant cavities to the process space within the process chamber and thereby create uniform plasma within the process space.

Claims

1. A method of processing a substrate using a microwave processing system comprising:

positioning a substrate on a movable substrate holder within a process space in a rectangular process chamber;

coupling a first cavity assembly to the rectangular process chamber using a first interface assembly, the first cavity assembly having a first electromagnetic (EM) energy tuning space therein, the first interface assembly including a first set of isolation assemblies, wherein a first set of EM-coupling regions are established in the first EM energy tuning space;

coupling each one from a first set of plasma-tuning rods to one of the isolation assemblies of the first set, the first set of plasma-tuning rods each having a first set of plasma-tuning portions in the process space and an EM-tuning portion in the first EM energy tuning space, each of the plasma-tuning portions being coupled to a respective one of the EM-coupling regions of the first set, wherein the first set of EM-tuning portions is configured to obtain EM energy from the first set of EM-coupling regions;

coupling to the first cavity assembly through a first cavity assembly wall a first set of slab control assemblies and coupling a first set of plasma-tuning slabs disposed proximate to the first set of EM-coupling regions in the first EM energy tuning space to the first set of slab control assemblies, each plasma-tuning slab of the first set being positioned a first EM-coupling distance from the EM-tuning portion of a plasma-tuning rod of the first set by a slab control assembly of the first set that is configured to tune the EM energy in a respective one of the EM-coupling regions of the first set;

coupling a first cavity control assembly to the first cavity assembly and coupling a first cavity-tuning slab to the first cavity control assembly so that the first cavity-tuning slab is positioned at a variable cavity tuning distance within the first EM energy space and configured to tune EM energy in the first EM energy tuning space;

coupling a second cavity assembly to the rectangular process chamber using a second interface assembly, the second cavity assembly having a second EM energy tuning space therein, the second interface assembly including a second set of isolation assemblies, wherein a second set of EM-coupling regions are established in the second EM energy tuning space;

coupling each one from a second set of plasma-tuning rods to one of the isolation assemblies of the second set, the second set of plasma-tuning rods each having plasma-tuning portions in the process space and an EM-tuning portion in the second EM energy tuning space, each of the plasma-tuning portions being coupled to a respective one of the EM-coupling regions of the second set, wherein the first set of EM-tuning portions is configured to obtain EM energy from the second set of EM-coupling regions;

coupling to the second cavity assembly through a second cavity assembly wall a second set of slab control assemblies and coupling a second set of plasma-tuning slabs disposed proximate to the second set of EM-coupling regions in the second EM energy tuning space to the second set of slab control assemblies, each plasma-tuning slab of the second set being positioned a second EM-coupling distance from the EM-tuning portion of a plasma-tuning rod of the second set by a slab control assembly of the second set that is configured to tune the EM energy in a respective one of the EM-coupling regions of the second set;

coupling a second cavity control assembly to the second cavity assembly and coupling a second cavity-tuning slab to the second cavity control assembly so that the second cavity-tuning slab is positioned at a variable cavity tuning distance within the second EM energy space and configured to tune EM energy in the second EM energy tuning space; and

coupling a controller to the first cavity control assembly, the second cavity control assembly, the first set of slab control assemblies, the second set of slab control assemblies, the first cavity assembly and the second cavity assembly, wherein the controller is configured to independently control the first set of slab control assemblies so as to control the first EM-coupling distance to tune each EM energy associated with each first set of the EM-coupling regions of the first set, the second set of slab control assemblies so as to control the second EM-coupling distance to tune each EM energy associated with each of the EM-coupling regions of the second set, and the first and second cavity control assemblies to tune the EM energies in the first and second EM energy tuning spaces, to thereby control plasma uniformity in the process space.

2. The method of claim 1, further comprising:

coupling a first coupling network to the first cavity assembly;

coupling a first matching network to the first coupling network;

coupling a first EM source to the first matching network, wherein the first EM source is configured to operate in a frequency range from 500 MHz to 5000 MHz, wherein the controller is coupled to the first EM source and configured to control the first EM source, thereby controlling the plasma uniformity in the process space;

coupling a second coupling network to the second cavity assembly;

coupling a second matching network to the second coupling network; and

coupling a second EM source to the second matching network, wherein the second EM source is configured to operate in a second frequency range from 500 MHz to 5000 MHz, wherein the controller is coupled to the second EM source and configured to control the second EM source, thereby controlling the plasma uniformity in the process space.

3. The method of claim 1, further comprising:

coupling a gas showerhead to the rectangular process chamber;

coupling a gas supply subassembly to the gas showerhead; and

coupling a gas supply system to the gas supply subassembly, wherein the gas showerhead is configured to introduce a process gas to the process space, wherein the controller is coupled to the gas supply system, to the gas supply subassembly, and to the gas showerhead and is configured to control the gas supply system, the gas supply subassembly, and the gas showerhead, thereby controlling the plasma uniformity in the process space.

4. The method of claim 3, wherein the process gas comprises two or more of:

C₄F₈, C₅F₈, C₃F₆, C₄F₆, CF₄, CHF₃, CH₂F₂, an inert gas, oxygen, CO, and CO₂.

5. The method of claim 3, wherein the process gas comprises two or more of:

HBr, Cl₂, NF₃, SF₆, CHF₃, CH₂F₂, an inert gas, oxygen, CO, and CO₂.

6. The method of claim 1, further comprising:

positioning the first cavity-tuning slab proximate to a first end of the first EM energy tuning space in the first cavity assembly;

wherein the first cavity-tuning slab is positioned at a first cavity-tuning distance from at least one wall of the first cavity assembly, wherein the controller is configured to control the first cavity-tuning distance, thereby controlling the plasma uniformity in the process space;

positioning the second cavity-tuning slab proximate to a second end of the second EM energy tuning space in the second cavity assembly;

wherein the second cavity-tuning slab is positioned at a second cavity-tuning distance from at least one wall of the second cavity assembly, wherein the controller is configured to control the second cavity-tuning distance, thereby controlling the plasma uniformity in the process space.

7. A microwave processing system for processing a substrate comprising:

a rectangular process chamber comprising a process space having a movable substrate holder therein;

a first cavity assembly coupled to the rectangular process chamber using a first interface assembly, the first cavity assembly having a first electromagnetic (EM) energy tuning space therein, the first interface assembly including a first set of isolation assemblies, wherein a first set of EM-coupling regions, each with EM energy therein, are established in the first EM energy tuning space;

a first set of plasma-tuning rods, each coupled to a respective one of the isolation assemblies of the first set, the first set of plasma-tuning rods each having a plasma-tuning portion in the process space and an EM-tuning portion in the first EM energy tuning space, each of the plasma-tuning portions being coupled to a respective one of the EM-coupling regions of the first set, wherein the first set of EM-tuning portions is configured to obtain EM energy from the first set of EM-coupling regions;

a first set of plasma-tuning slabs disposed proximate to the first set of EM-coupling regions in the first EM energy tuning space and a first set of slab control assemblies coupled to the first set of plasma-tuning slabs through a first cavity assembly wall, each plasma-tuning slab of the first set being positioned a first EM-coupling distance from the EM-tuning portion of a plasma-tuning rod of the first set by a respective slab control assembly of the first set that is configured to tune the EM energy in a respective one of the EM-coupling regions of the first set;

a first cavity-tuning slab positioned at a variable cavity tuning distance within the first EM energy tuning space by a first cavity control assembly coupled to the cavity tuning slab and configured to tune EM energy in the first EM energy tuning space;

a second cavity assembly coupled to the rectangular process chamber using a second interface assembly, the second cavity assembly having a second EM energy tuning space therein, the second interface assembly including a second set of isolation assemblies, wherein a second set of EM-coupling regions, each with EM energy therein, are established in the second EM energy tuning space;

a second set of plasma-tuning rods, each coupled to a respective one of the isolation assemblies of the second set, the second set of plasma-tuning rods each having a plasma-tuning portion in the process space and an EM-tuning portion in the second EM energy tuning space, each of the plasma-tuning portions being coupled to a respective one of the EM-coupling regions of the second set, wherein the second set of EM-tuning portions is configured to obtain EM energy from the second set of EM-coupling regions;

a second set of plasma-tuning slabs disposed proximate to the second set of EM-coupling regions in the second EM energy tuning space and a second set of slab control assemblies coupled to the second set of plasma-tuning slabs through a second cavity assembly wall, each plasma-tuning slab of the second set being positioned a second EM-coupling distance from the EM-tuning portion of a plasma-tuning rod of the second set by a respective slab control assembly of the second set that is configured to tune the EM energy in a respective one of the EM-coupling regions of the second set;

a second cavity-tuning slab positioned a variable cavity tuning distance within the second EM energy tuning space by a second cavity control assembly coupled to the cavity tuning slab and configured to tune EM energy in the second EM energy tuning space; and

a controller coupled to the first cavity control assembly, the second cavity control assembly, the first set of slab control assemblies, the set of second slab control assemblies, the first cavity assembly and the second cavity assembly, wherein the controller is configured to independently control the first set of slab control assemblies so as to control the first EM-coupling distance to tune each EM energy associated with each of the EM-coupling regions of the first set, the second set of slab control assemblies so as to control the second EM-coupling distance to tune each EM energy associated with each of the EM-coupling regions of the second set, and the first and second cavity control assemblies to tune the EM energies in the first and second EM energy tuning spaces, to thereby control plasma uniformity in the process space.

8. The microwave processing system of claim 7, wherein the first set of plasma-tuning rods, the first cavity assembly, the second set of plasma-tuning rods, and the second cavity assembly comprise dielectric material.

9. The microwave processing system of claim 7, further comprising:

a first coupling network coupled to the first cavity assembly;

a first matching network coupled to the first coupling network;

a first EM source coupled to the first matching network, wherein the first EM source is configured to operate in a frequency range from 500 MHz to 5000 MHz;

wherein the controller is coupled to the first EM source and configured to control the first EM source, thereby controlling the plasma uniformity in the process space;

a second coupling network coupled to the second cavity assembly;

a second matching network coupled to the second coupling network;

a second EM source coupled to the second matching network, wherein the second EM source is configured to operate in a second frequency range from 500 MHz to 5000 MHz;

wherein the controller is coupled to the second EM source and configured to control the second EM source, thereby controlling the plasma uniformity in the process space.

10. The microwave processing system of claim 7, further comprising:

a gas showerhead coupled to the rectangular process chamber;

a gas supply subassembly coupled to the gas showerhead; and

a gas supply system coupled to the gas supply subassembly, wherein the gas showerhead is configured to introduce a process gas to the process space, wherein the controller is coupled to the gas supply system, to the gas supply subassembly, and to the gas showerhead and is configured to control the gas supply system, the gas supply subassembly, and the gas showerhead, thereby controlling the plasma uniformity in the process space.

11. The microwave processing system of claim 10, wherein the process gas comprises two or more of:

C₄F₈, C₅F₈, C₃F₆, C₄F₆, CF₄, CHF₃, CH₂F₂, an inert gas, oxygen, CO, and CO₂.

12. The microwave processing system of claim 10, wherein the process gas comprises two or more of:

HBr, Cl₂, NF₃, SF₆, CHF₃, CH₂F₂, an inert gas, oxygen, CO, and CO₂.

13. The microwave processing system of claim 7, further comprising:

the first cavity-tuning slab proximate to a first end of the first EM energy tuning space in the first cavity assembly,

wherein the first cavity-tuning slab is positioned at the first cavity-tuning distance from at least one wall of the first cavity assembly and the controller is configured to control the first cavity-tuning distance to control the EM energy in the first EM energy tuning space, thereby controlling the plasma uniformity in the process space;

the second cavity-tuning slab proximate to the first end of the second EM energy tuning space in the second cavity assembly,

wherein the second cavity-tuning slab is positioned at the second cavity-tuning distance from at least one wall of the second cavity assembly and the is configured to control the second cavity-tuning distance to control the EM energy in the second EM energy tuning space, thereby controlling the plasma uniformity in the process space.

14. The microwave processing system of claim 13, wherein the first cavity-tuning slab, the first cavity-control assembly, the second cavity-tuning slab, and the second cavity-control assembly comprise dielectric material.