Patent Grant
7679024
This application contains subject matter that is related to the subject matter of the following applications, which are assigned to the same assignee as this application. The below-listed applications are hereby incorporated herein by reference:
“Methods and Arrangement for Creating a Highly Efficient Downstream Microwave Plasma System,” by Kamarehi et al., application Ser. No. 11/317,874, filed on even date herewith.
“Methods and Arrangement for Implementing Highly Efficient Plasma Traps,” by Kamarehi et al., application Ser. No. 11/318,360, filed on even date herewith.
“Plasma Shield Arrangement for O-rings,” by Wang et al., application Ser. No. 11/317,517, filed on even date herewith.
Advances in plasma processing have provided for the growth in the semiconductor industry. In plasma processing, a gas distribution arrangement may be utilized to pump process gases into a plasma processing system. Gas distribution systems interact with power sources, such as microwaves, to generate plasma used in substrate processing.
Gas distribution arrangement may include a gas inlet, from which process gases (e.g., O2, N2, N2:H2, He:H2, water vapor, fluorinated compounds, etc.) may be dispatched. Process gas flow may typically be directed to the center of a plasma tube. In some examples, the diameter of a conventional gas inlet may generally be narrower than a conventional plasma tube. In an example, conventional gas inlet diameter may measure approximately 0.25 inches to 0.50 inches, whereas a conventional plasma tube diameter may measure approximately 1 inch. To facilitate discussion,
In addition, heat influx from the interaction may traverse back beyond ignition zone 106 toward gas inlet 102 to attack o-rings 112 and 114. Generally, coolant may flow through a cooling arrangement 110, which may enclose a large portion of plasma tube 104, to reduce the thermal loading that may occur in plasma tube 104. However, in some examples, o-rings 112 and 114 may be coupled directly to plasma tube 104 without a direct cooling arrangement. Consequently, heat influx from the plasma may flow through plasma tube 104 and may heat up adjacent o-rings 112 and 114. Because o-rings are poor conductor of heat, o-rings 112 and 114 may absorb the influx heat, thereby resulting in the destruction of o-rings 112 and 114. To prolong the life of o-rings, operators may cycle process intervals (i.e., power down the system for a time) to allow time for o-rings to cool. Consequently, average substrate processing time may become relatively long in comparison to actual processing time.
To provide some protection to o-rings, a gas inlet may be enclosed within a plug.
Given the need to stay competitive, a gas distribution arrangement is needed that is capable of evenly distributing the process gases into an ignition zone while also providing protection to the vulnerable o-rings.
The invention relates, in an embodiment, a gas distribution arrangement configured to provide a process gas downstream to a plasma tube of a plasma processing chamber. The plasma tube has a top end. The arrangement includes a body having a first end. The first end has a width larger than the plasma tube and a protrusion end adapted to be inserted into the top end. The arrangement also includes a gas inlet vertically disposed in the body. The gas inlet extends from the first end toward the protrusion end and the gas inlet terminates before extending through the protrusion end. The arrangement further includes a plurality of directional inlet channels extending from a lower end of the gas inlet through the protrusion end.
In another embodiment, the invention relates to a gas distribution arrangement configured to provide a process gas downstream to a plasma tube of a plasma processing chamber. The plasma tube has a top end and at least one o-ring disposed around the plasma tube proximate the top end. The arrangement includes a gas inlet. The arrangement also includes a plurality of directional inlet channels extending from a lower end of the gas inlet. The plurality of directional inlet channels is in communication with the gas inlet. At least one of the directional inlet channels directs the process gas into an o-ring adjacent area of a plasma tube wall that is adjacent to the at least one o-ring.
In yet another embodiment, the invention relates to a gas distribution arrangement configured to provide a process gas downstream to a plasma tube of a plasma processing chamber. The plasma tube has a top end and at least one o-ring disposed around the plasma tube proximate the top end. The arrangement includes a gas inlet. The arrangement also includes a plurality of side channels extending from a section of a wall of the gas inlet toward a wall of the plasma tube. The plurality of side channels is in communication with the gas inlet. At least one of the side channels directs the process gas into an o-ring adjacent area of the wall of the plasma tube that is adjacent to the at least one o-ring.
In yet another embodiment, the invention relates to a gas distribution arrangement configured to provide a process gas downstream to a plasma tube of a plasma processing chamber. The plasma tube has a top end. The arrangement includes a body having a first end. The first end has a width larger than the plasma tube and a protrusion end adapted to be inserted into the top end. The arrangement also includes a gas inlet vertically disposed in the body. The gas inlet extends from the first end toward the top end and terminates before extending through the top end. The arrangement further includes a plurality of side channels extending from a section of a wall of the gas inlet toward a wall of the plasma tube. At least a portion of the plurality of side channels is disposed above the top end. The plurality of side channels is in communication with the gas inlet. At least one of the side channels directs the process gas into an o-ring adjacent area of a plasma tube wall that is adjacent to the at least one o-ring.
These and other features of the present invention will be described in more detail below in the detailed description of the invention and in conjunction with the following figures.
The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which:
The present invention will now be described in detail with reference to a few embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps and/or structures have not been described in detail in order to not unnecessarily obscure the present invention.
In accordance with embodiments of the present invention, there is provided a gas distribution arrangement within a downstream plasma source. Gas distribution arrangement may be configured to provide process gases downstream to a plasma processing chamber. Embodiments of the invention provide for gas distribution arrangements which may provide uniform distribution of process gases within ignition area. Further, gas distribution may be performed in a manner that minimizes damages to o-rings.
Process gases may flow from gas inlet 304 through a plurality of directional inlet channels 306 at a high speed rate of flow. In an embodiment, total cross-sectional areas of plurality of directional inlet channels 306 may be equal to or less than cross-sectional area of gas inlet 304. One skilled in the art is aware that process gases are usually dispatched at high flow rates. Without directional inlet channels 306, process gases may pass through gas inlet 304 and enter plasma tube 308 in a focused high-speed jet stream. Given the short distance between gas inlet 304 and ignition zone 310, the gas stream may stay focused when passing through to ignition zone 310. Since the entire ignition zone may be filled with electrical energy (such as microwave energy), the power absorption to the gases may be limited with a focused and high speed gas jet stream. By using directional inlet channels 306, the process gases may be effectively dispersed within a very short distance, allowing the process gases to fill the larger diameter plasma tube 308 quickly. As the gases fill plasma tube 308, the process gas flow may slow down significantly when entering ignition zone 310. With slow flowing and evenly distributed process gases entering ignition zone 310, the conditions for generating plasma may have now become optimal. Power absorption by the process gases may be enhanced greatly.
In an embodiment, some directional inlet channels may be configured to allow process gases to be directed toward o-ring adjacent area 312 of plasma tube 308. This arrangement may create a cooling effect which may help reduce thermal loading around o-ring adjacent area 312, which, in turn may prolong the life of o-rings 314 and 316, which may be disposed around the top end of plasma tube 308. As discussed herein, o-ring adjacent area refers to an area where plasma tube wall may be coupled to one or more o-rings.
A plug gas injector component is an embodiment that may offer a particular advantage in protecting o-rings as well as offer an efficient mechanism for distributing process gases throughout an ignition zone of a plasma tube, as shown in
Unlike the non-plug configuration, gas inlet 404 and/or directional inlet channels 406 may be configured to be enclosed within a plug 402. Gas inlet 404 may be vertically disposed in the elongated body, extending from first end 420 to a portion of the protrusion end 418. Attached to lower end of gas inlet 404 and extending to a lower edge of protrusion end 418 may be a plurality of directional inlet channels 406.
Once inserted into plasma tube 408, protrusion end 418 may extend into an area beyond o-rings 414 and 416 creating substantially no gap between protrusion end 418 and plasma tube wall. Thus, protrusion end 418 may obstruct heat influx escaping from ignition zone 410 from reaching o-rings 414 and 416, which may be disposed around the top end of plasma tube 408. In an embodiment, plug gas injector may be formed from a good conductor of heat material, such as aluminum or ceramic. Thus, heat influx may be directed away from o-rings and head toward a more conductive path.
Another gas distribution arrangement is shown in
By using side channels 508, high speed process gases may enter into o-ring adjacent area 510 and bounce off the plasma tube wall to be distributed throughout ignition zone 512 of plasma tube 506. In addition, process gases may interact with plasma tube wall within o-ring adjacent area 510 to create an artificial cooling arrangement providing effective protection against thermal loading for o-rings 514 and 516, which may be disposed around the top end of plasma tube 506.
Accordingly, peripheral gas injector may be combined with a plug mechanism as shown in
In an embodiment, a lower edge of protrusion end 608 may be disposed below at least one o-ring. Protrusion end 608 may include an upper section 608a and a lower section 608b, in which upper section 608a may have a cross-sectional area less than a cross-sectional area of lower section 608b. Protrusion end is dimensioned such that a gap 614 between the wall of lower section 608b and the wall of plasma tube 616 may be minimized. Also, an o-ring adjacent area 610 may be formed between the wall of upper section 608a and the wall of plasma tube 616.
Process gases may flow out from side channels 606 into an o-ring adjacent area 610. To reach ignition zone 612, in an embodiment, process gases may have to travel from o-ring adjacent area 610 through a gap 614. In another embodiment, protrusion end 608 may include a plurality of hollow channels 620 from which process gases may travel to be disbursed into plasma tube 616. By implementing a plurality of hollow channels, process gases may be more evenly distributed into ignition zone 612.
The plug peripheral gas injector configuration may provide a particular advantage in protecting o-rings. In an example, once inserted, protrusion end 608 may extend beyond o-ring adjacent area 610. Thus, heat influx which may travel back upstream toward adjacent area 610 may be blocked by protrusion end 608. In an embodiment, plug peripheral gas injector may be formed from a good conductor of heat material, such as aluminum or ceramic. As can be appreciated, heat influx may be directed away from o-rings 626 and 618, which may be disposed around the top end of plasma tube 616, toward a more conductive path.
As can be appreciated from embodiments of the invention, the different gas distribution arrangements provide for more uniform gas distribution into the ignition zone. This allows for a more efficient absorption of power source to generate plasma for substrate processing. Further, the o-rings may be preserved better by diminishing the impact typically caused by heat influx. Thus, ownership cost may be significantly reduced as the structural viability of the o-rings remains uncompromised for a longer period of time, thereby resulting in fewer repairs to the o-rings and longer time duration between scheduled maintenance.
While this invention has been described in terms of several embodiments, there are alterations, permutations, and equivalents, which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.
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