Method and processing system for plasma-enhanced cleaning of system components
A method for plasma-enhanced cleaning of a system component in a batch-type processing system and a method for monitoring and controlling the cleaning. The cleaning is performed by introducing a cleaning gas in a process chamber of the batch-type processing system, forming a plasma by applying power to a system component within the process chamber, exposing a material deposit in the process chamber to the plasma to form a volatile reaction product, and exhausting the reaction product from the processing system. Monitoring of the processing system can be carried out to determine cleaning status of the processing system, and based upon the status from the monitoring, the processing system is controlled for either continuing the exposing and monitoring or stopping the cleaning process. A batch-type processing system is provided that allows plasma-enhanced cleaning of system components, and a system is provided with monitoring and controlling capability.
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The present invention relates to chamber processing, and more particularly to plasma-enhanced cleaning of system components during a cleaning process performed in a process chamber of a batch-type processing system.
BACKGROUND OF THE INVENTIONMany semiconductor production processes are performed in process chambers such as plasma etch chambers, plasma deposition chambers, thermal processing chambers, chemical vapor deposition chambers, atomic layer deposition chambers, etc. Processing of substrates in the process chambers can lead to formation of material deposits on system components exposed to the process environment that requires periodic cleaning of the process chambers to remove the material deposits. System components are commonly replaced or cleaned after material deposits threaten particle problems, in between incompatible processes to be run in sequence, after detrimental processing conditions, or after poor processing results are observed. Alternately, system components can be cleaned or replaced according to a predetermined maintenance schedule that can, for example, be based on the number of operating hours or accumulated depositions.
The length of a cleaning process and equipment damage from over-cleaning can depend on the type of processing system, (e.g., batch-type vs. single wafer), amount and type of material deposits formed on the system components, the cleaning gas used for removing the material deposits, and process conditions such as pressure and temperature. In a batch-type processing system, slow rates of removal of material deposits from system components in a thermal cleaning process can require long cleaning times and result in unacceptable reduction in throughput for the processing system.
SUMMARY OF THE INVENTIONA method is provided for plasma-enhanced cleaning of a batch-type processing system and a method is further provided for monitoring the process system to determine when to stop the cleaning process. The cleaning process includes introducing a cleaning gas in a process chamber of the batch-type processing system, forming a plasma by applying power to a system component within the process chamber, exposing a material deposit in the process chamber to the plasma to form a volatile reaction product, and exhausting the reaction product from the process chamber. In one embodiment, the system component to which power is applied is selected from a process tube, a substrate holder, and a substrate holder support. In another embodiment, during the cleaning process, the processing system is monitored to determine status of the processing system, and based upon the status from the monitoring, the method includes either continuing the exposing and monitoring or stopping the cleaning process.
A batch-type processing system is provided that allows plasma-enhanced cleaning of system components and a system is further provided that allows monitoring the status of the cleaning. The batch-type processing system includes a process chamber containing a material deposit, a system component within the process chamber, a gas injection system configured for introducing a cleaning gas in the process chamber, a plasma source configured for forming a plasma by applying power to the system component, wherein the plasma is capable of reacting with the material deposit to form a volatile reaction product, a vacuum pumping system configured for exhausting the reaction product from the process chamber, and a controller configured to control the processing system. In one embodiment, the system component to which power is applied is selected from a process tube, a substrate holder, and a substrate holder support. In another embodiment, the plasma processing system includes a chamber monitoring system configured for monitoring the process chamber to determine the status of the process chamber and to transmit the status to the controller, which is further configured to receive the status and control the processing system in response to the status.
The chamber monitoring system can include an optical monitoring system for detecting light emission or light absorption of a gas in the process chamber, an optical monitoring system for detecting interaction of light with the system component and/or the material deposit, or a mass sensor to detect a mass signal from a gas.
BRIEF DESCRIPTION OF THE DRAWINGSIn the figures:
The gas injection system 104 can introduce gases into the process chamber 102 for purging the process chamber 102, for preparing the process chamber 102, for cleaning the process chamber 102, and for processing the substrates 110. A plurality of gas injector lines (not shown) can be arranged to flow gases into the process chamber 102. The gases can be introduced into volume 118, defined by the inner section 116, to expose substrates 110 thereto. Thereafter, the gases can flow into the volume 120, defined by the inner section 116 and the outer section 114, to be continuously exhausted from the process chamber 102 by the vacuum pumping system 106.
Substrates 110 can be loaded into the process chamber 102 and processed using the substrate holder 112. The batch-type processing system 100 can allow for a large number of tightly stacked substrates 110 to be processed, thereby resulting in high substrate throughput. A substrate batch size can, for example, be about 150, substrates (wafers), or less. Alternately, the batch size can be about 25 substrates, or less. The processing system 100 can be configured to process substrates of various sizes, for example 200 mm substrates, 300 mm substrates, or larger substrates. The substrates 110 can, for example, comprise semiconductor substrates (e.g., Si or compound semiconductor), LCD substrates, and glass substrates. In addition to clean substrates, substrates at various stages of device processing can be utilized.
The processing system 100 is capable of forming and sustaining a plasma in the process chamber 102. In the embodiment shown in
In an alternate embodiment of the invention, RF power can be applied to the substrate holder 112 and/or the substrate holder support 126 at multiple frequencies. Furthermore, the impedance match network 96 serves to maximize the transfer of RF power to plasma in processing chamber 102 by minimizing the reflected power. Match network topologies (e.g., L-type, π-type, T-type) and automatic control methods are known in the art.
In another embodiment of the invention, RF power can be applied to multiple sections of the substrate holder 112 and/or the substrate holder support 126. In addition, the substrate holder 112 can contain multiple dummy wafers (e.g., SiC substrates) to tailor the plasma density in the process chamber 102.
In another embodiment of the invention, the substrate holder 112 and/or the substrate holder support 126 may be grounded and the RF power coupled to the inner section 116 to provide the plasma.
The batch-type processing system 100 can be controlled by a controller 124 capable of generating control voltages sufficient to control the batch-type processing system 100 as well as monitor outputs from the batch-type processing system 100. Moreover, the controller 124 can be coupled to and exchange information with process chamber 102, gas injection system 104, heater 122, chamber monitoring system 108, RF source 98, match network 96, and vacuum pumping system 106. For example, a program stored in the memory of the controller 124 can be utilized to control the aforementioned components of the batch-type processing system 100 according to a desired process, and to perform any functions associated with monitoring the process. One example of controller 124 is a DELL PRECISION WORKSTATION 610™, available from Dell Corporation, Austin, Tex.
Real-time process monitoring can be carried out using chamber monitoring system 108. In accordance with the present invention, the chamber monitoring system 108 can be positioned for real-time in-situ monitoring of the gaseous environment in the process chamber 120. Alternately, the chamber monitoring system 108 can be positioned to monitor the process chamber effluent. The chamber monitoring system 108 is a versatile monitoring system and includes a sensor capable of real-time process monitoring and may, for example, be a mass sensor (mass spectrometer) or an optical monitoring system for monitoring light emission or light absorption by a process gas and reaction products. The chamber monitoring system 108 can provide qualitative and quantitative analysis of the gaseous environment in process chamber 102. Process parameters that can be monitored using the chamber monitoring system 108 include ratios of gaseous species, gas purities, and reaction products including etch products.
In one embodiment of the invention, the chamber monitoring system 108 can include an optical monitoring system for monitoring interaction (reflection and/or transmission) of light with a system component and/or a material deposit.
The processing system 1 can further include a cap cover (not shown) to protect the lid 27 from the processing environment. The cap cover can, for example, be made of quartz or SiC.
The processing system 1 is capable of forming and maintaining a plasma in the process chamber 10. In the embodiment shown in
In an alternate embodiment of the invention, RF power can be applied at multiple frequencies. Furthermore, the impedance match network 76 serves to maximize the transfer of RF power to plasma in processing chamber 10 by minimizing the reflected power.
A plurality of gas injector lines 45 can be arranged around the manifold 2 to supply a plurality of gases into the process tube 25 through the gas injector lines 45. In
The vacuum pumping system 88 comprises a vacuum pump 86, a trap 84, and an automatic pressure controller (APC) 82. The vacuum pump 86 can, for example, include a dry vacuum pump capable of a pumping speed up to 20,000 liters per second (and greater). During processing, gases can be introduced into the process chamber 10 via the gas injection system 94 and the process pressure adjusted by the APC 82. The trap 84 can collect unreacted precursor material and reaction products from the process chamber 10.
Analogous to the processing system 100 in
A controller 90 includes a microprocessor, a memory, and a digital I/O port capable of generating control voltages sufficient to communicate and activate inputs to the processing system 1 as well as monitor outputs from the processing system 1. Moreover, the controller 90 is coupled to and can exchange information with gas injection system 94, motor 28, chamber monitoring system 92, heaters 20, 15, 65, and 70, vacuum pumping system 88, RF source 78, and match network 76.
It is to be understood that the processing systems 100,1 in
Processing of substrates can lead to formation of a material deposit on a surface, such as a surface of a system component in a process chamber. The material deposit can contain one or more types of material, for example Si, silicon germanium (SiGe), SiN, silicon dioxide (SiO2), doped Si, and dielectric materials including high-k metal oxides such as HfO2, HfSiOx, ZrO2, ZrSiOx.
In one embodiment of the invention, a method is provided for plasma-enhanced cleaning of a material deposit from system components. Plasma excitation of a cleaning gas can enhance the formation of a volatile reaction product when the plasma or activated cleaning gas is exposed to a material deposit. For example, the material deposit can be Si-containing and the cleaning gas can contain a halogen-containing gas (e.g., ClF3, HF, HCl, F2, NF3, CF4). The volatile reaction product can, for example, be a silicon halide (e.g., SiF4, SiCl4, and SiBr4) or a silicon oxyhalide (e.g., SixOyXz, where X is F, Cl, or Br). The cleaning gas can further contain an inert gas selected from at least one of Ar, He, Ne, Kr, Xe, and N2.
The cleaning process is monitored by a chamber monitoring system, where the monitoring can include determining if the intensity level of a monitored signal has reached a threshold value, thereby arriving at a determination of whether the system component has been sufficiently cleaned, and based on the determination, either continuing with the cleaning process or stopping the cleaning process. The cleaning process can be optimized to be selective to removing the material deposits from the system components while minimizing erosion of the system components.
A signal intensity from a reaction product can be monitored to determine an endpoint of a process. Correlation of a signal intensity to an endpoint of a process can be carried out by a test process that is performed while detecting a signal intensity and monitoring status of a process chamber. Status of a process chamber can, for example, be evaluated by inspecting a system component during the test process and correlating the inspected results to a detected threshold intensity recorded when a desired endpoint of the process is observed. The threshold intensity may be a fixed intensity value, or a ratio of measured signal intensity and initial signal intensity (measured at the start of the process).
Returning to
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise that is specifically described herein. For example, the process steps described herein and recited in the claims may be performed in a sequence other than the sequence in which they are described or listed herein. As should be understood by one of ordinary skill in the art, only those process steps necessary to the performance of a later process steps are required to be performed before the later process step is performed.
Claims
1. A method of plasma-enhanced cleaning of a batch-type processing system, the method comprising performing a cleaning process, including:
- introducing a cleaning gas in a process chamber of the batch-type processing system, the process chamber having a material deposit on at least one surface therein;
- forming a plasma by applying power to a system component within the process chamber, the system component selected from the group consisting of: a substrate holder for holding a plurality of substrates, a substrate holder support for supporting the substrate holder, and a process tube;
- exposing the material deposit in the process chamber to the plasma to form a volatile reaction product; and
- exhausting the reaction product from the process chamber.
2. The method according to claim 1 further comprising monitoring a signal from the processing system, the signal being indicative of the progress of the cleaning process, and based upon the signal, performing one of the following: (a) continue performing the cleaning process and continue monitoring; or (b) stopping the cleaning process.
3. The method according to claim 2 wherein the monitoring further comprises determining if an intensity level of the signal has reached a threshold value.
4. The method according to claim 3, wherein performing (b) occurs after determining that the threshold value has been reached.
5. The method according to claim 2, wherein the monitoring comprises using an optical monitoring system to detect light emission or light absorption of a gas in the process chamber.
6. The method according to claim 2, wherein the monitoring comprises using an optical monitoring system to detect interaction of light with at least one of the system component or the material deposit.
7. The method according to claim 2, wherein the monitoring comprises using a mass sensor to detect a mass signal of a gas in the process chamber.
8. The method according to claim 1, wherein the introducing further comprises flowing at least one of ClF3, HF, HCl, F2, NF3, or CF4 into the process chamber.
9. The method according to claim 8, wherein the introducing further comprises flowing at least one of Ar, He, Ne, Kr, Xe, or N2.
10. A method of plasma-enhanced cleaning of a batch-type processing system, the method comprising:
- performing a cleaning process, including: introducing a cleaning gas in a process chamber of the batch-type processing system, the process chamber having a material deposit on at least one surface therein, forming a plasma by applying power to a system component within the process chamber, exposing the material deposit in the process chamber to the plasma to form a volatile reaction product, and exhausting the reaction product from the process chamber;
- monitoring a signal from the processing system, the signal being indicative of the progress of the cleaning process; and
- based upon the signal, performing one of the following: (a) continue performing the cleaning process and continue monitoring; or (b) stopping the cleaning process.
11. The method according to claim 10 wherein the monitoring further comprises determining if an intensity level of the signal has reached a threshold value.
12. The method according to claim 11, wherein performing (b) occurs after determining that the threshold value has been reached.
13. The method according to claim 10, wherein the monitoring comprises using an optical monitoring system to detect light emission or light absorption of a gas in the process chamber.
14. The method according to claim 10, wherein the monitoring comprises using an optical monitoring system to detect interaction of light with at least one of the system component or the material deposit.
15. The method according to claim 10, wherein the monitoring comprises using a mass sensor to detect a mass signal of a gas in the process chamber.
16. The method according to claim 10, wherein the introducing further comprises flowing at least one of ClF3, HF, HCl, F2, NF3, or CF4 into the process chamber.
17. The method according to claim 16, wherein the introducing further comprises flowing at least one of Ar, He, Ne, Kr, Xe, or N2.
18. A batch-type processing system, comprising:
- a process chamber containing a material deposit on at least one surface therein;
- an electrode that is a system component within the process chamber and that is selected from the group consisting of: a substrate holder for holding a plurality of substrates, a substrate holder support for supporting the substrate holder, and a process tube;
- a gas injection system configured for introducing a cleaning gas in the process chamber;
- a plasma source configured for forming plasma in the process chamber by applying power to the electrode, wherein the plasma is capable of reacting with the material deposit to form a volatile reaction product;
- a vacuum pumping system configured for exhausting the reaction product from the process chamber; and
- a controller configured to control the processing system.
19. The processing system according to claim 18, further comprising a chamber monitoring system configured for monitoring a signal from the processing system to determine cleaning status of the processing system and configured to transmit the status to the controller, and wherein the controller is further configured to receive the status and to control the processing system in response to the status.
20. The processing system according to claim 19, wherein the chamber monitoring system is further configured to determine if an intensity level of the signal has reached a threshold value, and based on the determination, either continue with the process or stop the process.
21. The processing system according to claim 19, wherein the chamber monitoring system comprises an optical monitoring system to detect light emission or light absorption of a gas in the process chamber.
22. The processing system according to claim 19, wherein the chamber monitoring system comprises an optical monitoring system to detect interaction of light with at least one of the system component or the material deposit.
23. The processing system according to claim 19, wherein the chamber monitoring system comprises a mass sensor to detect a mass signal in the process chamber.
24. The processing system according to claim 18, wherein the electrode is the process tube and the plasma source comprises a RF generator and a match network coupled to the process tube.
25. The processing system according to claim 18, wherein the plasma source comprises a RF generator and a match network coupled to the system component within the process tube.
26. The processing system according to claim 18, wherein the plasma source is configured for applying RF power to multiple sections of the substrate holder in the process chamber.
27. The processing system according to claim 26, wherein the substrate holder further contains multiple dummy wafers.
28. The processing system according to claim 18, wherein the system component comprises at least one of quartz, Al2O, SiN, SiC, doped silicon, SiC-coated graphite, or Si-coated graphite.
29. The processing system according to claim 18, wherein the material deposit comprises at least one of Si, SiGe, SiN, SiO2, doped Si, HfO2, HfSiOx, ZrO2, or ZrSiOx.
30. The processing system according to claim 18, wherein the gas injection system is configured for introducing at least one of ClF3, HF, HCl, F2, NF3, or CF4 in the process chamber.
31. The processing system according to claim 30, wherein the gas injection system is further configured for introducing at least one of Ar, He, Ne. Kr, Xe, or N2 in the process chamber.
32. A batch-type processing system, comprising:
- a process chamber containing a material deposit on at least one surface therein;
- a system component within the process chamber;
- a gas injection system configured for introducing a cleaning gas in the process chamber,
- a plasma source configured for forming plasma in the process chamber by applying power to the system component, wherein the plasma is capable of reacting with the material deposit to form a volatile reaction product;
- a vacuum pumping system configured for exhausting the reaction product from the process chamber;
- a chamber monitoring system configured for monitoring a signal from the processing system to determine cleaning status of the processing system and to transmit the status; and
- a controller configured to receive the status from the chamber monitoring system and to control the processing system in response to the status.
33. The processing system according to claim 32, wherein the chamber monitoring system is further configured to determine if an intensity level of the signal has reached a threshold value, and based on the determination, either continue with the process or stop the process.
34. The processing system according to claim 32, wherein the chamber monitoring system comprises an optical monitoring system to detect light emission or light absorption of a gas in the process chamber.
35. The processing system according to claim 32, wherein the chamber monitoring system comprises an optical monitoring system to detect interaction of light with at least one of the system component or the material deposit.
36. The processing system according to claim 32, wherein the chamber monitoring system comprises a mass sensor to detect a mass signal in the process chamber.
37. The processing system according to claim 32, wherein the process chamber comprises a process tube and the plasma source comprises a RF generator and a match network coupled to the process tube.
38. The processing system according to claim 32, wherein the process chamber comprises a process tube and the plasma source comprises a RE generator and a match network coupled to the system component within the process tube.
39. The processing system according to claim 32, wherein the plasma source is configured for applying RE power to multiple sections of a substrate holder in the process chamber.
40. The processing system according to claim 39, wherein the substrate holder further contains multiple dummy wafers.
41. The processing system according to claim 32, wherein the system component comprises at least one of a process tube, a shield, a ring, a baffle, a gas injector, a substrate holder, a substrate holder support, a cap cover, or a liner.
42. The processing system according to claim 32, wherein the system component comprises at least one of quartz, Al2O, SiN, SiC, doped silicon, SiC-coated graphite, or Si-coated graphite.
43. The processing system according to claim 32, wherein the material deposit comprises at least one of Si, SiGe, SiN, SiO2, doped Si, HfO2, HfSiOx, ZrO2, or ZrSiOx.
44. The processing system according to claim 32, wherein the gas injection system is configured for introducing at least one of ClF3, HF, HCl, F2, NF3, or CF4 in the process chamber.
45. The processing system according to claim 44, wherein the gas injection system is further configured for introducing at least one of Ar, He, Ne, Kr, Xe, or N2 in the process chamber.
Type: Application
Filed: Mar 25, 2004
Publication Date: Sep 29, 2005
Applicant: Tokyo Electron Limited of TBS Broadcast Center (Tokyo)
Inventors: John Kostenko (LaGrangeville, NY), David O'Meara (Poughkeepsie, NY)
Application Number: 10/808,691