Apparatus and methods for using high frequency chokes in a substrate deposition apparatus
In certain aspects, a substrate deposition apparatus, including a gas tube coupled to a gas source, an RF power source and a substrate processing chamber, is provided. The gas tube is adapted to carry process gas and cleaning plasma from the gas source/remote plasma gas source to the substrate processing chamber and the RF power source is adapted to couple RF power to the substrate processing chamber. Furthermore an RF choke coupled to the RF power source and the gas source wherein the RF choke is adapted to attenuate a voltage difference between the RF power source and the gas source to prevent plasma formation in the gas tube during substrate processing. Numerous other aspects are provided.
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The present application claims priority to U.S. Provisional Patent Application Ser. No. 60/714,723 filed Sep. 6, 2005 and entitled “APPARATUS AND METHODS FOR AN RF CHOKE” which is hereby incorporated by reference herein for all purposes.
FIELD OF THE INVENTIONThe present invention relates generally to high or radio frequency (RF) chokes and specifically to RF chokes for plasma processing chambers.
BACKGROUNDWith each successive technology generation, substrate processing chambers may increase in size to accommodate larger substrates. Larger substrate processing chambers may require an increase in the RF power used to perform a substrate plasma process in the substrate processing chamber. What is needed are improved methods and apparatus that allow existing processing chambers to be cost effectively enhanced to support processing operations that use higher RF powers.
SUMMARY OF THE INVENTIONThe invention provides a substrate deposition apparatus, comprising a gas tube coupled to a gas source, an RF power source and a substrate processing chamber. The gas tube is adapted to carry gas from the gas source to the substrate processing chamber, and the RF power source is adapted to couple RF power to the substrate processing chamber. Furthermore, an RF choke is coupled to the RF power source and the gas source wherein the RF choke is adapted to attenuate a voltage difference between the RF power source and the gas source.
Other features and aspects of the present invention will become more fully apparent from the following detailed description, the appended claims, and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Substrate processing chambers may be adapted to perform a cleaning process using a remotely generated “cleaning” plasma that is delivered to the chamber via the same channel that is used for delivering the regular process gases to the chamber. Thus, the cleaning process may use a cleaning plasma tube, which may be coupled to an RF power source, external to the substrate processing chamber. Accordingly, an RF power source may be coupled to both the substrate plasma processing chamber and the cleaning plasma tube. The cleaning plasma tube may be coupled to a gas source and the RF power source. However, this may lead to undesired electrical coupling of the RF power source to the gas delivery device. To avoid this according to the present invention, a device may be employed to electrically decouple or attenuate the voltage difference between the RF power and the gas source. This may be accomplished by placing a device such as a dielectric gas tube (e.g., ceramic plasma tube) between the RF power source and the gas delivery device that may also serve as the cleaning plasma tube. However, this may result in a localized high density electrical field, due to non uniform attenuation of the voltage difference between the gas source and the RF power source, which may cause unintended plasma in the shared dielectric gas tube/cleaning plasma tube during substrate processing.
A more uniform attenuation of the voltage may allow relatively higher RF power to be delivered to the substrate processing chamber before plasma is ignited in the plasma tube. In other words, the present invention may be used to prevent process plasma from forming in the cleaning plasma tube during substrate processing using higher RF powers. A resistor may be placed between RF power source and the gas delivery apparatus and may ensure an approximately uniform attenuation of voltage difference between the RF power source and the gas delivery system. However, the resistor may be expensive, susceptible to damage and take up an undesired amount of volume. Therefore, there may be a desire for an inexpensive, compact apparatus adapted to ensure an approximately uniform attenuation of the voltage from the RF power source and the gas delivery apparatus.
In accordance with the present invention, an RF choke is provided. In a first embodiment, the RF choke may include a wire wrapped around a hollow plastic core or form. The plastic core may include grooves machined into the surface so as to allow the wire to form a coil traversing the length of the plastic core. Alternatively, in a second embodiment of the RF choke, a wire with a dielectric coating may be provided. The pitch between the wires may be established by the thickness of the dielectric coating on the conductive portion of the wire when the wire may be wrapped around an object such as a form or a tube.
The RF choke may be electrically coupled to a gas source, an RF power source and a substrate processing chamber. The coupling of the RF choke, or specifically, the coiled wire to the RF power source and the gas source, may induce a voltage drop along the length of the wire. By providing a wire wrapped into a coil, in accordance with the first two embodiments, an approximately uniform voltage drop along the length of the wire may be realized. Thereby, the voltage drop that induces plasma in the substrate processing chamber and/or gas tube may be realized and/or repeatable. These aspects of the invention are discussed below.
With reference to
Still with reference to
Alternatively, there may be a need to perform a clean process in the substrate processing chamber 110. The clean process may be performed by flowing cleaning plasma gas to the gas tube 104 via the gas delivery device 108 (e.g., remote plasma clean source). During the flow of the cleaning plasma gas, the RF power source 114 may couple RF power to the RF choke 102 via the RF delivery device 116. In this manner, plasma may be maintained in the gas tube 104. Furthermore, the voltage level of the chamber distribution device 112 (Vbt) that induces plasma in the gas tube 104 may be known. The plasma may provide reactive species such chlorine which may flow to the substrate processing chamber 110 via the chamber distribution device 112 to perform the clean process.
Still with reference to
With reference to
Still with reference to
Similar to the first embodiment in operation, during the substrate and/or clean process, the RF end bolt 206 may be electrically excited to a voltage by the RF power source 114. In addition, the gas end bolt 204 may be at a voltage level near earth ground. Thus, the insulated coiled wire 304 may have a voltage drop along the length of the wire that is approximately equal to voltage Vbs and/or Vbt or any other suitable voltage. Furthermore, the voltage drop along the length of the insulated coiled wire 304 may be approximately uniform. In this manner, the RF power output from the RF power source 114 which may induce ignition of the plasma in the gas tube 104 may be approximately known and/or repeatable.
Turning to
With reference to
The remote cleaning plasma source 504 may be adapted to provide a fluid for processing. For example, the remote cleaning plasma source 504 may be adapted to vaporize water to form gaseous water (e.g., steam). Such fluid may be employed by the processing chamber.
The diffuser 506 may comprise anodized aluminum although any suitable material may be employed to distribute the fluid. As depicted in
The diffuser 506 may be employed to distribute the fluid in a desired manner. For example, it may be desired to distribute the fluid evenly inside the processing chamber to ensure uniform processing. Alternatively, the diffuser 506 may distribute the fluid in a non-uniform manner to ensure that the fluid concentrates in desired regions of the processing chamber.
As depicted in
The gas tube 508 may be adapted to convey the fluid from the remote cleaning plasma source 504 to the diffuser 506. The gas tube 508 may also insulate (e.g., electrically) the fluid from electrical or other energy sources. By insulating the fluid from the energy sources, the gas tube 508 may ensure that a desired amount of energy is coupled to the fluid. In addition or alternatively, the gas tube 508 may be adapted to hold other components of the present invention. For example, as will be discussed below, the gas tube 508 may be adapted to mechanically support other components of the present invention.
Still with reference to
The matching network 514 may be coupled to the RF choke 510 and the lid 502. The matching network 514 may include other components that are not discussed in detail in this application. The components may be inductors and/or capacitors although other suitable components may be employed. The external shell of the matching network 514 may be aluminum although any suitable material may be employed.
The matching network 514 may be adapted to couple a source (e.g., electrical) to the lid 502 via the choke 510. The matching network 514 may be employed to match the electrical load presented to the matching network 514 (e.g., electrical load of the processing chamber, RF choke, etc.) to the load of the source. In the same or alternative embodiments, the matching network 514 may couple energy to the processing chamber via the RF choke 510.
The grounded connector 516 may comprise aluminum although any suitable material may be employed. The grounded connector 516 is depicted in
The RF choke form 602 may comprise a plastic such as polyamide although any suitable material may be employed. For example, the RF choke form 602 may comprise a ceramic material in addition to other materials. The RF choke form 602 may be adapted to receive and support the conductive coil 604, as will be described below with reference to
With reference to
With reference to
Although the groove 608 is depicted as u-shaped valleys, any suitable shape may be employed. For example, in an alternative embodiment, the groove 608 may be v-shaped or rectangular shaped. The groove 608 may be any suitable depth suitable for controlling the depth of the wire of the conductive coil 604 in the groove 608. Also, as depicted in
The foregoing description discloses only exemplary embodiments of the invention. Modifications of the above disclosed apparatus and method which fall within the scope of the invention will be readily apparent to those of ordinary skill in the art. Accordingly, while the present invention has been disclosed in connection with exemplary embodiments thereof, it should be understood that other embodiments may fall within the spirit and scope of the invention, as defined by the following claims.
Claims
1. A substrate deposition apparatus, comprising:
- a gas tube coupled to a gas source, an RF power source and a substrate processing chamber,
- wherein the gas tube is adapted to carry gas from the gas source to the substrate processing chamber, and
- wherein the RF power source is adapted to couple RF power to the substrate processing chamber; and
- an RF choke coupled to the RF power source and the gas source,
- wherein the RF choke is adapted to attenuate a voltage difference between the RF power source and the gas source.
2. The apparatus of claim 1, wherein the gas tube is disposed within the RF choke.
3. The apparatus of claim 1, wherein the RF choke includes a wire wrapped into a coil.
4. The apparatus of claim 3, wherein the RF choke further includes a core disposed inside the wire wrapped into a coil.
5. The apparatus of claim 4, wherein the core is adapted to ensure the pitch of the coil is substantially constant.
6. The apparatus of claim 3, wherein the wire is coated with a dielectric material.
7. The apparatus of claim 6, wherein the RF choke further includes a core disposed inside the wire wrapped into a coil.
8. The apparatus of claim 1, wherein the gas tube includes a dielectric material.
9. The apparatus of claim 8, wherein the RF choke includes a wire wrapped into a coil.
10. The apparatus of claim 9, wherein the RF choke further includes a core disposed inside the wire wrapped into a coil.
11. The apparatus of claim 10, wherein the core is adapted to ensure the pitch of the coil is substantially constant.
12. The apparatus of claim 3, wherein the wire is coated with a dielectric material.
13. The apparatus of claim 12, wherein the gas tube is disposed inside the coil.
14. The apparatus of claim 1, wherein the RF choke is further adapted to approximately uniformly attenuate the voltage difference between the RF power source and the gas delivery system.
15. A method, comprising:
- providing a gas tube, a gas source, an RF power source and a substrate processing chamber;
- carrying gas from the gas source to the substrate processing chamber via the gas tube;
- coupling RF power to the substrate processing chamber;
- providing an RF choke;
- attenuating a voltage difference between the RF power source and the gas source with the RF choke.
16. The method of claim 15, wherein providing an RF choke includes disposing the RF choke around the gas tube.
17. The method of claim 15, wherein providing an RF choke includes providing a wire wrapped into a coil.
18. The method of claim 17, wherein providing a wire wrapped into a coil includes disposing the wire around the gas tube.
19. The method of claim 18, wherein disposing the wire around the gas tube further includes ensuring the pitch of the wire is substantially constant.
20. The method of claim 15, wherein providing a gas tube includes providing dielectric material.
21. The method of claim 20, wherein providing the RF choke includes providing a wire wrapped into a coil.
22. The method of claim 21, wherein providing a wire wrapped into a coil includes disposing the wire around the gas tube.
23. The method of claim 22, wherein disposing the wire around the gas tube further includes ensuring the pitch of the wire is substantially constant.
24. The method of claim 17, wherein providing a wire wrapped into a coil includes providing a wire coated with dielectric material.
25. The method of claim 24, wherein providing a wire coated with a dielectric material includes disposing the wire coated with a dielectric material around the gas tube.
26. A choke for use with a substrate processing chamber, comprising:
- a wire formed into a coil; and
- a form disposed inside the coil,
- wherein the form is adapted to ensure the pitch of the coil is substantially constant, and
- wherein the wire is coated with a dielectric material.
27. The choke of claim 26, further including a gas tube disposed inside the form.
28. The choke of claim 26, wherein the choke is adapted to approximately uniformly attenuate a voltage difference between an RF power source and a gas delivery system.
Type: Application
Filed: Sep 1, 2006
Publication Date: Mar 8, 2007
Applicant:
Inventor: Carl Sorensen (Morgan Hill, CA)
Application Number: 11/514,676
International Classification: B08B 6/00 (20060101); H05H 1/24 (20060101); C23C 16/00 (20060101);