DELAYED PULSING FOR PLASMA PROCESSING OF WAFERS

• US 20200135458A1
• Filed: 10/29/2018
• Published: 04/30/2020
• Est. Priority Date: 10/29/2018
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: MEHROTRA, AKHIL, VIDYARTHI, VINAY SHANKAR, AGARWAL, DAKSH, SADIGHI, SAMANEH, KENNEY, JASON, DHINDSA, RAJINDER
• Granted Patent: US 11,817,312 B2
• Time in Patent Office: Days
• CPC Class Codes: H01J 37/32146 Amplitude modulation, includes pulsing
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/308 using masks H01L21/3063, H01L21/3065 take precedence
• CPC Class Codes: H01L 21/67069 for drying etching
• CPC Class Codes: H01L 21/67126 Apparatus for sealing, encapsulating, glassing, decapsulating or the like processes H01L23/02, H01L23/28
• CPC Class Codes: H01L 21/6719 characterized by the construction of the processing chambers, e.g. modular processing chambers
• CPC Class Codes: H01L 21/6831 using electrostatic chucks
• CPC Class Codes: H01L 22/26 Acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection, in-situ thickness measurement endpoint detection arrangements in CMP apparatus B24B37/013, in discharge apparatus H01J37/32

Abstract

A method, apparatus and system for processing a wafer in a plasma chamber system, which includes at least a plasma generating element and a biasing electrode, include generating a plasma in the plasma chamber system by applying a source RF source power to the plasma generating element for a first period of time of a pulse period of the RF source power, after the expiration of the first period of time, removing the source RF source power, after a delay after the removal of the RF source power, applying an RF bias signal to the biasing electrode for a second period of time to bias the generated plasma towards the wafer, and after the expiration of the second period of time, removing the RF bias signal from the biasing electrode before a next pulse period of the RF source power. The generated plasma biased toward the wafer is used to process the wafer.

Claims

1. A method in a plasma chamber system for processing a wafer, comprising:

generating a plasma by applying RF source power to a plasma generating element of the plasma chamber for a first period of time of a pulse period of the RF source power;

after an expiration of the first period of time, removing the RF source power from the plasma generating element;

after a delay after the removal of the RF source power from the plasma generating element, applying an RF bias signal to bias the generated plasma towards the wafer for a second period of time during the pulse period of the RF source power; and

after an expiration of the second period of time, removing the RF bias signal before a next pulse period of the RF source power.

2. The method of claim 1, wherein a length of the delay between the removal of the RF source power and the application of the RF bias signal is selected to produce a neutral density to ion density ratio that produces a high selectivity etching of different materials on a surface of the wafer during processing.

3. The method of claim 1, wherein a length the delay between the removal of the RF source power and the application of the RF bias signal is selected to produce a neutral density to ion density ratio that reduces aspect ratio-dependent etch of at least one material on a surface of the wafer during processing resulting in improved etch uniformity.

4. The method of claim 1, wherein a deposition process is performed on the wafer during the application of the RF source power to the plasma generating element and an etch process is performed on the wafer during the application of the RF bias signal.

5. The method of claim 1, wherein the RF bias signal is applied to a pedestal of the plasma chamber system used to support the wafer.

6. The method of claim 1, wherein the RF source power and the RF bias signal comprise different duty cycles.

7. The method of claim 1, wherein the first period of time and the second period of time combined do not exceed the pulse period of the RF source power.

8. The method of claim 1, wherein the RF source power is removed from the plasma generating element by turning off a source of the RF source power.

9. The method of claim 1, wherein the RF source power is removed from the plasma generating element by blocking the RF source power from reaching the plasma generating element.

10. The method of claim 1, wherein the RF bias signal is removed by turning off a source of the RF bias signal.

11. An apparatus for controlling processing of a wafer in a plasma chamber system, comprising:

a processor; and

a memory coupled to the processor, the memory having stored therein at least one of programs or instructions executable by the processor to configure the apparatus to;

generate a plasma by applying RF source power to a plasma generating element of the plasma chamber for a first period of time of a pulse period of the RF source power;

after an expiration of the first period of time, remove the RF source power from the plasma generating element;

after a delay after the removal of the RF source power from the plasma generating element, apply an RF bias signal to bias the generated plasma towards the wafer for a second period of time during the pulse period of the RF source power; and

after an expiration of the second period of time, remove the RF bias signal before a next pulse period of the RF source power.

12. The apparatus of claim 11, wherein the RF bias signal is applied to a biasing electrode of the plasma chamber system to bias the generated plasma towards the wafer.

13. The apparatus of claim 12, wherein the biasing electrode comprises a support pedestal of the plasma chamber system used to support the wafer.

14. The apparatus of claim 11, further comprising at least one of an RF power source or an RF bias signal source.

15. The apparatus of claim 14, further comprising at least one blocking device for blocking power from at least one of the RF power source or the RF bias signal source.

16. The apparatus of claim 14, wherein the RF source power is removed from the plasma generating element by turning off the RF power source.

17. The apparatus of claim 14, wherein the RF bias signal is removed from the biasing electrode by turning off the RF bias signal source.

18. A non-transitory computer-readable medium having stored thereon at least one program, the at least one program including instructions which, when executed by a processor, cause the processor to perform a method in a plasma chamber system for processing a wafer, comprising:

generating a plasma by applying RF source power to a plasma generating element of the plasma chamber for a first period of time of a pulse period of the RF source power;

after an expiration of the first period of time, removing the RF source power from the plasma generating element;

after a delay after the removal of the RF source power from the plasma generating element, applying an RF bias signal to bias the generated plasma towards the wafer for a second period of time during the pulse period of the RF source power; and

after an expiration of the second period of time, removing the RF bias signal before a next pulse period of the RF source power.

19. The non-transitory computer-readable medium of claim 18, wherein the processor performs a deposition process on the wafer during the application of the RF source power to the plasma generating element and performs an etch process on the wafer during the application of the RF bias signal.

20. The non-transitory computer-readable medium of claim 18, wherein the processor selects a length of the delay between the removal of the RF source power and the application of the RF bias signal to at least one of produce a neutral density to ion density ratio that produces a high selectivity etching of different materials on a surface of the wafer during processing or to produce a neutral density to ion density ratio that reduces aspect ratio-dependent etch of at least one material on a surface of the wafer during processing resulting in improved etch uniformity