阅读说明：本技术 原位光学腔室表面及处理传感器 (In-situ optical chamber surface and process sensor ) 是由 林庄嘉 乌彭铎·乌梅塔拉 史蒂文·E·巴巴扬 连·雷 于 2020-04-02 设计创作，主要内容包括：本文揭露的实施方式包含光学传感器系统及使用这些系统的方法。在一实施方式中,光学传感器系统包括：外壳及光学路径,所述光学路径穿过所述外壳。在一实施方式中,所述光学路径包括第一端及第二端。在一实施方式中,反射器位于所述光学路径的所述第一端处,且透镜位于所述反射器及所述光学路径的所述第二端之间。在一实施方式中,光学传感器进一步包括开口,所述开口在所述透镜及所述反射器之间穿过所述外壳。(Embodiments disclosed herein include optical sensor systems and methods of using these systems. In one embodiment, an optical sensor system includes: a housing and an optical path through the housing. In one embodiment, the optical path includes a first end and a second end. In an embodiment, a reflector is located at the first end of the optical path and a lens is located between the reflector and the second end of the optical path. In an embodiment, the optical sensor further comprises an opening through the housing between the lens and the reflector.)

1. An optical sensor system comprising:

a housing;

an optical pathway passing through the housing, wherein the optical pathway comprises a first end and a second end;

a reflector located at the first end of the optical path; and

an opening through the housing between the second end of the optical path and the reflector.

2. The optical sensor system of claim 1, further comprising:

a light source optically coupled to the optical path; and

a sensor optically coupled to the optical path.

3. The optical sensor system according to claim 2, wherein the light source is a single wavelength source.

4. The optical sensor system according to claim 2, wherein the light source is a broadband light source.

5. The optical sensor system of claim 2, wherein the light source and the sensor are optically coupled to the optical pathway by a fiber optic cable.

6. The optical sensor system of claim 5, wherein the fiber optic cable includes a splitter.

7. The optical sensor system of claim 2, further comprising:

a band pass filter located at a position along an optical path between the sensor and the opening.

8. The optical sensor system of claim 2, wherein the sensor is a spectrometer or a photodiode.

9. The optical sensor system of claim 2, wherein the light source and the sensor are integrated into the housing.

10. A method for measuring a process condition or chamber condition in a process chamber, comprising:

acquiring a reference signal, wherein the step of acquiring the reference signal comprises:

emitting electromagnetic radiation from a source external to the chamber, wherein the electromagnetic radiation propagates along an optical path between the source and a reflector in the chamber;

reflecting the electromagnetic radiation back along the optical path using the reflector; and

sensing the reflected electromagnetic radiation using a sensor optically coupled to the optical path;

acquiring a processed signal, wherein the step of acquiring the processed signal comprises:

sensing, using the sensor, electromagnetic radiation emitted in the processing chamber that travels along the optical path; and

comparing the processed signal to the reference signal.

11. The method of claim 10, wherein the reference signal is acquired when no processing is performed in the chamber.

12. The method of claim 10, wherein the reference signal is acquired during processing in the chamber.

13. An optical sensing array for a plasma processing chamber, comprising:

a plurality of optical sensing systems oriented around a perimeter of the process chamber, wherein each of the plurality of optical sensing systems comprises:

a housing;

an optical pathway passing through the housing, wherein the optical pathway comprises a first end and a second end;

a reflector located at the first end of the optical path; and

an opening through the housing between the second end of the optical path and the reflector.

14. The optical sensing array of claim 13, wherein the plurality of optical sensing systems are configured to provide plasma conditions, wall conditions, or uniformity data of plasma conditions and wall conditions.

15. The optical sensing array of claim 13, wherein the plurality of optical sensing systems are configured to provide chamber drift (drift) monitoring.

Technical Field

Embodiments relate to the field of semiconductor manufacturing, and in particular to systems and methods for providing in-situ optical sensors for monitoring chamber surface conditions and chamber processing parameters.

Background

Changes in the chamber surfaces affect various process parameters. For example, redeposition of etch byproducts on the chamber walls can change the etch rate of a given process. Accordingly, when processing substrates in a chamber, the etch rate (or other processing parameters) may change and result in non-uniform processing between substrates.

To address the change in processing conditions, Optical Emission Spectroscopy (OES) has been implemented in process chambers. OES involves monitoring the emission spectrum of a plasma in a chamber. A window is disposed along the chamber wall and the emission spectrum may pass through the window along an optical path to a sensor outside the chamber. As the plasma spectrum changes, a qualitative analysis of the processing operation can be inferred. In particular, OES is useful for determining when the end of a processing operation is reached. To provide optimal measurements, the window is designed to prevent deposition along the optical path. Furthermore, although endpoint analysis is possible, no process currently exists for conducting quantitative analysis using existing OES systems.

Disclosure of Invention

Embodiments disclosed herein include optical sensor systems and methods of using these systems. In one embodiment, an optical sensor system includes: a housing and an optical path passing through the housing. In one embodiment, the optical path includes a first end and a second end. In one embodiment, a reflector is located at the first end of the optical path and a lens is located between the reflector and the second end of the optical path. In an embodiment, the optical sensor further comprises an opening through the housing between the lens and the reflector.

In one embodiment, a method for measuring a process condition or a chamber condition in a process chamber using an optical sensor includes acquiring a reference signal. In one embodiment, the step of acquiring the reference signal comprises: emitting electromagnetic radiation from a source external to the chamber, wherein the electromagnetic radiation propagates along an optical path between the source and a reflector in the chamber; reflecting the electromagnetic radiation back along the optical path using the reflector; and sensing the reflected electromagnetic radiation using a sensor optically coupled to the optical path. In an embodiment, the method further comprises acquiring a processing signal, wherein the step of acquiring the processing signal comprises sensing electromagnetic radiation emitted in the processing chamber that travels along the optical path using the sensor. In one embodiment, the method further comprises comparing the processed signal with the reference signal.

In one embodiment, an optical sensing array for a plasma processing chamber includes: a plurality of optical sensing systems oriented around a perimeter of the processing chamber. In one embodiment, each of the plurality of optical sensing systems includes: a housing; an optical pathway passing through the housing, wherein the optical pathway includes a first end and a second end; a reflector at the first end of the optical path; a lens between the reflector and the second end of the optical path; and an opening through the housing between the lens and the reflector.

Drawings

FIG. 1 is a cross-sectional view of a chamber having an optical sensor through a chamber wall according to an embodiment.

FIG. 2 is a cross-section of a perspective view of a sensor housing according to an embodiment.

Fig. 3A is a cross-sectional view of an optical sensor through a chamber wall and illustrating an optical path through a sensor housing according to an embodiment.

FIG. 3B is a cross-sectional view of an optical sensor after a layer of material is deposited on a reflector according to an embodiment.

FIG. 4A is a cross-sectional view of an optical sensor having a source and a sensor integrated into a sensor housing according to an embodiment.

FIG. 4B is a cross-sectional view of an optical sensor with a filter along an optical path according to an embodiment.

Figure 5 is a plan view of a process chamber having an array of optical sensors through a chamber wall according to an embodiment.

Fig. 6A is a process flow diagram depicting a process for determining wall conditions or process conditions using an optical sensor, according to an embodiment.

Fig. 6B is a process flow diagram depicting a process for acquiring a reference signal according to an embodiment.

FIG. 7 illustrates a block diagram of an exemplary computer system that may be used with an optical sensor having an optical path through a chamber wall, according to an embodiment.

Detailed Description

The systems and methods described herein include optical sensors for in situ monitoring of chamber conditions and/or process conditions in a chamber. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments. It will be apparent to one skilled in the art that embodiments may be practiced without these specific details. In other instances, well-known aspects have not been described in detail so as not to unnecessarily obscure the embodiments. Further, it should be understood that the various embodiments shown in the figures are illustrative representations and are not necessarily drawn to scale.

As noted above, currently available Optical Emission Spectroscopy (OES) systems can provide qualitative measurements to achieve functions such as endpoint determination, but currently do not provide accurate quantitative measurements. Existing OES systems are unable to directly measure process parameters such as etch rate. Accordingly, embodiments disclosed herein include an optical sensor system that includes an optical path through which both a reference signal and a plasma emission spectrum pass. For example, the optical path starts at the light source, passes through the chamber wall, and reflects off a reflector surface in the chamber along the optical path back toward the sensor. Since the reference signal and the emission spectrum pass along the same optical path, the reference signal can be used to determine the loss attributable to the optical path without opening the chamber and interrupting operation. This allows for accurate and quantitative measurement of the emission spectrum. Accordingly, the calibrated plasma emission spectrum can be used to determine process parameters, such as etch rate.

Furthermore, while currently available OES systems are designed to prevent deposition along the optical path, embodiments disclosed herein include reflector surfaces that are exposed to the processing environment. In some embodiments, the reflector surface may be selected to substantially match the interior surface of the chamber. In this way, the deposition on the reflector surface is substantially similar to the deposition seen on the interior surfaces of the chamber. The reflector surface interacts with the electromagnetic radiation emitted by the source and can therefore be used to determine the nature of the deposited film or wall material transition. For example, the absorption of portions of the spectrum of electromagnetic radiation may be related to a particular material composition and/or thickness of the film.

Accordingly, embodiments disclosed herein allow for quantitative in situ measurements of process conditions and/or chamber conditions. Because the embodiments disclosed herein provide quantitative measurements, embodiments may allow chamber-matched measurements (i.e., comparing a single process performed in different chambers). In some embodiments, a single optical sensor may be included in the process chamber. Other embodiments may include an array of optical sensors disposed around the perimeter of the process chamber. These embodiments may allow for the acquisition of chamber uniformity data (e.g., plasma uniformity, chamber surface uniformity, etc.). In addition, these embodiments may also provide an indication of chamber anomalies (e.g., chamber drift).

Referring now to FIG. 1, a cross-sectional view of a processing tool 100 is illustrated, in accordance with one embodiment. In one embodiment, the processing tool 100 includes a chamber 105. For example, the chamber 105 may be adapted for low pressure processing operations. In one embodiment, the processing operation may include generating a plasma 107 in the chamber 105. In one embodiment, the substrate support 108 is located in the chamber 105. The substrate support 108 may be a chuck (e.g., an electrostatic chuck, a vacuum chuck, etc.) or any other suitable support upon which one or more substrates may be placed during processing.

In one embodiment, the processing tool 100 may include an in situ optical sensor 120. The in-situ optical sensor 120 passes through the surface of the chamber 105 such that a first portion of the optical sensor 120 is inside the chamber 105 and a second portion of the optical sensor is outside the chamber 105. In one embodiment, the optical sensor 120 is illustrated through a sidewall of the chamber 105. However, it should be understood that the optical sensor 120 may be disposed through any surface of the chamber 105.

In the illustrated embodiment, a single optical sensor 120 is shown. However, it should be understood that embodiments are not limited to these configurations, and more than one optical sensor 120 may be included in the processing tool 100. Furthermore, the optical sensor 120 only requires a single optical opening (i.e., window) through the chamber 105. As will be described in more detail below, the optical path includes a reflector 121 that reflects electromagnetic radiation from the source 137 back through the same opening 121. This is in contrast to prior systems that required an optical path across the volume of the chamber 105 and required at least two optical openings through the chamber.

In one embodiment, the optical sensor 120 includes a housing. In an embodiment, the housing may include a first housing 124 and a second housing 122. In an embodiment, the first housing 124 may be fastened to the second housing 122 using any suitable fastener. In other embodiments, the housing may be a unitary structure. That is, the first housing 124 and the second housing 122 may be combined into a single structure. Further, although the first housing 124 and the second housing 122 are disclosed, it should be understood that the housings may include any number of components coupled together.

In an embodiment, the first housing 124 may extend through an opening in the chamber 105 and into the chamber interior space. For example, the extension (e.g., tube 126) may pass through an opening in the chamber 105. In one embodiment, the tube 126 may be an optically transparent material. For example, the tube 126 may be quartz. However, it should be understood that the tube 126 need not be optically transparent. In some embodiments, the tube 126 may be a ceramic or metallic material. Further, although a tube 126 is described, it should be understood that any elongated member may extend into the space of the chamber 105. Specifically, any structure capable of supporting the reflector 121 in the inner space of the chamber 105 may be used.

In an embodiment, one or more openings 123 may be positioned along the length of the tube 126. The one or more openings 123 allow electromagnetic radiation from the plasma 107 to enter the optical sensor 120. In addition, the opening 123 exposes the reflector 121 to the processing environment. Exposing the reflector 121 to the processing environment allows the surface of the reflector 121 to be modified in substantially the same manner as the interior surfaces of the chamber are modified during processing operations. For example, byproducts deposited on the interior surfaces of the chamber 105 may also be deposited on the reflector 121. In particular embodiments, the reflector 121 may comprise the same material as the interior surface of the chamber 105. Accordingly, the change in the surface of the reflector 121 can be considered to substantially match the change in the interior surface of the chamber 105. In this way, monitoring of the chamber surface may be carried out by the optical sensor 120.

In some embodiments, the reflector 121 may be a replaceable component. That is, the reflector 121 may be a component that is removable from the first housing 124. For example, the reflector 121 may be attached to a cap that covers the end of the tube 126. Having a removable reflector allows the reflector 121 to be replaced after the useful life has expired. In addition, different reflector materials may be used to match the interior surfaces of the chamber for various processing tools.

In some embodiments, the lens 125 may be secured between the first housing 124 and the second housing 122. A lens 125 is positioned along the optical path between the source 137 and the reflector 121 to focus the electromagnetic radiation passing along the optical path. In some embodiments, the lens 125 may be part of a seal that closes an opening through the chamber 105. For example, an O-ring or the like may abut against a surface of the lens 125 facing the chamber 105.

In an embodiment, the optical sensor 120 may further include a source 137 and a sensor 138. The source 137 and the sensor 138 may be optically coupled to the optical path. For example, a fiber optic cable 132 may extend from the second housing 122. In an embodiment, fiber optic cable 132 may include splitter 134, splitter 134 branching into fiber optic cable 135 to source 137 and fiber optic cable 136 to sensor 138.

In an embodiment, source 137 may be any suitable source for propagating electromagnetic radiation along an optical path. In particular, embodiments include a high precision source 137. The high-precision source 137 provides a known electromagnetic spectrum that can be used as a reference baseline for measurements using the optical sensor 120. In one embodiment, the source 137 may be a single wavelength source. For example, the source 137 may be a laser or a Light Emitting Diode (LED). In other embodiments, the source 137 may be a broadband light source. For example, the source 137 may be an arc flash lamp (e.g., a xenon flash lamp).

In an embodiment, sensor 138 may be any suitable sensor for detecting electromagnetic radiation. In one embodiment, the sensor 138 may comprise a spectrometer. For example, the spectrometer may have a Charge Coupled Device (CCD) array. In other embodiments, the sensor 138 may have a photodiode that is sensitive to a particular wavelength of electromagnetic radiation.

Referring now to FIG. 2, a cross-sectional view of a three-dimensional view of a housing of an optical sensor 220 is shown, according to an embodiment. As illustrated, the optical pathway 228 extends through the housing. For example, the optical path 228 extends along a channel in the second housing 222, through the lens 225, and through the tube 226 of the first housing 224 toward the reflector 221. In an embodiment, an opening 223 through the tube 226 allows electromagnetic radiation from the processing environment (e.g., from the plasma) to enter the housing and propagate along an optical path 228. The opening 223 also exposes the reflector 221 to the processing environment inside the chamber. Accordingly, the deposition or other transitions of the surface of the reflector 221 may be monitored to determine changes in the interior surface of the chamber.

As illustrated in fig. 2, the reflector 221 is a cap attached on the end of the tube 226. Accordingly, the reflector 221 may be replaced by removing the cover and attaching a second cover having the second reflector 221. In addition, FIG. 2 illustrates a channel 227 proximate to the lens 225. In an embodiment, the channel 227 may be sized to receive an O-ring (not shown) against the first housing 224 and the lens 225. Accordingly, a vacuum seal can be maintained, even if there is an opening through the chamber wall.

As described above with respect to fig. 1, the housing of the optical sensor 220 may alternatively comprise a single component or more than two components (i.e., more than the first housing 224 and the second housing 222). Additionally, the tube 226 may be replaced with any elongated structure that can support a reflector along the optical path 228. For example, one or more bundles extending from the first housing 224 may be used to replace the tube 226.

Referring now to fig. 3A and 3B, a pair of cross-sectional views depicts a process using an optical sensor according to an embodiment.

Referring now to fig. 3A, a cross-sectional view at the beginning of processing of a substrate is illustrated. As illustrated, the optical sensor 320 is substantially similar to the optical sensors 120 and 220 described above. For example, a housing is illustrated that includes a first housing 324, a second housing 322, a lens 325, a reflector 321. Reflector 321 is illustrated in fig. 3A as floating. That is, only the opening 323 of the support structure is illustrated. However, it should be understood that the reflector 321 is connected to the first housing 324 in an out-of-plane configuration in cross-section. For example, one or more bundles or tubes may be used to connect reflector 321 to first housing 324.

In an implementation, the reference signal 341 may be generated by a source (not shown) and optically coupled to the optical path through the housings 324, 322. For example, reference signal 341 may propagate along fiber optic cable 332 before entering enclosure 322. The reference signal 341 may then propagate toward the reflector 321 and reflect back along the optical path as the reflected signal 342. The reflected signal 342 may be optically coupled with the fiber optic cable 332 and communicated to a sensor (not shown).

Since the source emits electromagnetic radiation having a known spectrum and intensity, the measurement of the reflected signal 342 by the sensor provides a baseline for loss along the optical path. That is, the difference between the measured value (e.g., spectrum and intensity) of the reflected signal 342 and the known spectrum and intensity of the source provides a measure of the loss inherent to the optical sensor 320. Accordingly, the subsequently acquired signal may be calibrated using known losses.

In particular, the sensor may also sense electromagnetic radiation emitted by the plasma. For example, plasma signal 343 may propagate through opening 323 of optical sensor 320 and along an optical path to a sensor (not shown). The measurement of the plasma signal 343 can then be calibrated by adding back the known losses inherent to the optical sensor. In this way, a quantitative measurement of the electromagnetic radiation emitted by the plasma may be provided.

Referring now to FIG. 3B, a cross-sectional view of the optical sensor 320 after the membrane 306 is disposed on the surface of the chamber 305 and on the surface of the reflector 321 is illustrated, according to an embodiment. In one embodiment, the film 306 may be a byproduct of a processing operation performed in the chamber 305. For example, film 306 may be a redeposition of a byproduct of the etching process. In embodiments where the surface of reflector 321 is the same material as the interior surface of chamber 305, film 306 on reflector 321 will represent film 306 on the interior surface of chamber 305.

Accordingly, one or more characteristics of the film 306 may also be determined using the optical sensor 320. In one embodiment, the reflected signal 342 may be measured to find a difference relative to the reference signal 341. For example, a decrease in a particular wavelength of the reflected signal 342 (relative to a reference signal) can be used to determine what material is deposited on the film. In particular, certain materials will preferentially absorb some portions of the spectrum of the reference signal 341. Accordingly, identifying portions of reflected signal 342 that have reduced intensity allows the composition of film 306 to be determined. In addition, changes in the reflected signal 342 can also identify film thickness.

Referring now to fig. 4A, a cross-sectional view of an optical sensor 420 through a surface of a chamber 405 is illustrated, according to an additional embodiment. The optical sensor 420 in fig. 4A is substantially similar to the optical sensor 320 in fig. 3A, except that the source 437 and the sensor 438 are integrated directly into the second housing 422. For example, reference signal 441 may pass through prism 439 and lens 425 toward reflector 421, and reflected signal 442 and plasma signal 443 may be redirected toward sensor 438 through prism 439. Accordingly, optical coupling of the source 437 and the sensor 438 to the optical path can be achieved without the need for fiber optic cables. These embodiments may also provide a more compact optical sensor 420.

Referring now to FIG. 4B, a cross-sectional view of an optical sensor 420 through a surface of chamber 405 is illustrated, according to an additional embodiment. Optical sensor 420 in fig. 4B is substantially similar to optical sensor 320 in fig. 3A, except that filter 445 is disposed along the optical path. In one embodiment, the filter 445 may provide a specific passband to improve the signal-to-noise ratio and improve the performance of the optical sensor. In one embodiment, filter 445 is positioned between lens 425 and the sensor (not shown). That is, the filter 445 is disposed outside of the chamber volume so as to be protected from the processing environment.

Referring now to FIG. 5, a plan view cross-sectional view of a processing tool 500 is illustrated, according to one embodiment. In one embodiment, the processing tool 500 may comprise a chamber 505. A substrate support 508 (e.g., a chuck, etc.) may be located within the chamber 505. In one embodiment, a plurality of optical sensors 520_A-EArranged in an array around the perimeter of chamber 505. Optical sensor 520_A-EMay be substantially similar to one or more of the optical sensors described above. In the illustrated embodiment, five optical sensors 520 are shown_A-E. However, it should be understood that any number of optical sensors 520 may be included in the processing tool 500. The use of multiple optical sensors 520 allows uniformity data to be acquired. For example, plasma uniformity and/or wall condition uniformity may be obtained. Additionally, chamber drift may also be determined.

Referring now to fig. 6A and 6B, a process flow diagram depicting a process for providing quantitative measurements in situ using an optical sensor is shown, in accordance with an embodiment.

Referring now to fig. 6A, process 660 begins with operation 661, which includes acquiring a reference signal that propagates along an optical path between a reflector inside the chamber and a sensor outside the chamber. In particular, operation 661 may include process 670 illustrated in fig. 6B.

Referring now to fig. 6B, the process 670 may begin at operation 671, which includes emitting electromagnetic radiation from a source external to the chamber. In an embodiment, the electromagnetic radiation propagates along an optical path between the source and a reflector in the chamber. Process 670 may then continue to operation 672, operation 672 including reflecting the electromagnetic radiation back along the optical path using a reflector. Process 670 may then proceed to operation 673, operation 673 including sensing the reflected electromagnetic radiation using a sensor optically coupled to the optical path.

Referring back to fig. 6A, the process 660 may then proceed to operation 662, operation 662 including acquiring a process signal by sensing electromagnetic radiation emitted in the process chamber that propagates along the optical path. In an embodiment, the process 660 may then proceed to operation 663, which includes comparing the processed signal to a reference signal.

In one embodiment, the comparison of the reference signal to the process signal can provide a quantitative measure of the process signal. In particular, the reference signal may provide a measure of the losses inherent to the optical sensor. Hereby, losses inherent in the optical sensor may be added back to the processed signal in order to provide a quantitative value for the processed signal. Obtaining quantitative values provides a more accurate picture of the processing conditions in the chamber. Furthermore, quantitative values may be compared across different chambers. In this way, chamber matching may be achieved in order to improve process uniformity across different chambers.

It should be understood that the processing operations disclosed in fig. 6A and 6B need not be performed in any particular order. That is, each signal may be acquired at any time. For example, in one embodiment, a reference signal may be acquired when no processing is being performed in the chamber. This provides a reference signal that is not altered by any electromagnetic radiation emitted by the plasma. However, it should be understood that in some embodiments, the reference signal may be acquired when the plasma is struck in the chamber. In other embodiments, the process signal may be acquired when the source is off. In these embodiments, a pure signal from the plasma can be acquired without any interference of the source light. However, it should be understood that in some embodiments, the source light may be on during the measurement of the processing signal. Further, it is understood that one or both of the reference signal and the process signal may be acquired during processing of one or more substrates in the chamber. As such, the measurement may be referred to as an in situ measurement.

Referring now to FIG. 7, a block diagram of an exemplary computer system 760 of a processing tool is illustrated, in accordance with one embodiment. In one embodiment, a computer system 760 is coupled to the processing tool and controls the processes in the processing tool. Computer system 760 can be connected (e.g., networked) to other machines in a Local Area Network (LAN), an intranet, an extranet, or the internet. Computer system 760 may operate in the capacity of a server or a client machine in a client-server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. Computer system 760 may be a Personal Computer (PC), a tablet PC, a set-top box (STB), a Personal Digital Assistant (PDA), a mobile telephone, a web appliance, a server, a network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine. Moreover, while only a single machine is illustrated with respect to computer system 760, the term "machine" shall also be taken to include any collection of machines (e.g., computers) that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein.

Computer system 760 may include a computer program product, or software 722, having a non-transitory machine-readable medium having stored thereon instructions, which may be used to program computer system 760 (or other electronic devices) to perform a process according to an embodiment. A machine-readable medium includes any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer). For example, a machine-readable (e.g., computer-readable) medium includes a machine (e.g., a computer) readable storage medium (e.g., read only memory ("ROM"), random access memory ("RAM"), magnetic disk storage media, optical storage media, flash memory devices, etc.), a machine (e.g., a computer) readable transmission medium (e.g., electrical, optical, acoustical or other form of propagated signals (e.g., infrared signals, digital signals, etc.)), and the like.

In one embodiment, computer system 760 comprises a system processor 702, a main memory 704 (e.g., Read Only Memory (ROM), flash memory, Dynamic Random Access Memory (DRAM) such as Synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM), etc.), a static memory 706 (e.g., flash memory, Static Random Access Memory (SRAM), etc.), and a secondary memory 718 (e.g., data storage device), which communicate with each other via a bus 730.

The system processor 702 represents one or more general-purpose processing devices such as a micro-system processor, central processing unit, or the like. More particularly, the system processor may be a Complex Instruction Set Computing (CISC) microsystem processor, a Reduced Instruction Set Computing (RISC) microsystem processor, a Very Long Instruction Word (VLIW) microsystem processor, a system processor implementing other instruction sets, or a system processor implementing a combination of instruction sets. The system processor 702 may also be one or more special-purpose processing devices such as an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a digital signal system processor (DSP), network system processor, or the like. The system processor 702 is configured to execute the processing logic 726 for performing the operations described herein.

Computer system 760 may further include a system network interface device 708 for communicating with other devices or machines. Computer system 760 may also include an image display unit 710 (e.g., a Liquid Crystal Display (LCD), a light emitting diode display (LED), or a Cathode Ray Tube (CRT)), an alphanumeric input device 712 (e.g., a keyboard), a cursor control device 714 (e.g., a mouse), and a signal generation device 716 (e.g., a speaker).

The secondary memory 718 may include a machine-accessible storage medium 731 (or more specifically, a computer-readable storage medium) having stored thereon one or more sets of instructions (e.g., software 722) that perform any one or more of the methods or functions described herein. The software 722 may also reside, completely or at least partially, within the main memory 704 and/or within the system processor 702 during execution thereof by the computer system 760, the main memory 704 and the system processor 702 also constituting machine-readable storage media. The software 722 may further be transmitted or received over a network 720 via the system network interface device 708. In an embodiment, the network interface device 708 may operate using RF coupling, optical coupling, acoustic coupling, or inductive coupling.

While the machine-accessible storage medium 731 is shown in an exemplary embodiment to be a single medium, the term "machine-readable storage medium" should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions. The term "machine-readable storage medium" shall also be taken to include any medium that is capable of storing or encoding a set of instructions for execution by the machine and that cause the machine to perform any one or more of the methodologies. Accordingly, the term "machine-readable storage medium" shall be taken to include, but not be limited to, solid-state memories, and optical and magnetic media.

In the foregoing specification, certain exemplary embodiments have been described. It will be apparent that various modifications can be made thereto without departing from the scope of the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.