WO2004032178A2

WO2004032178A2 - Plasma processing system and method

Info

Publication number: WO2004032178A2
Application number: PCT/US2003/030051
Authority: WO
Inventors: Audunn Ludviksson; Eric J. Strang; Andrej S. Mitrovic
Original assignee: Tokyo Electron Limited
Priority date: 2002-09-30
Filing date: 2003-09-25
Publication date: 2004-04-15
Also published as: US20050189069A1; AU2003278885A1; TW200414832A; JP2006501681A; WO2004032178A3; TWI238680B

Abstract

A plasma processing system and method for operating a diagnostic system in conjunction with a plasma processing system are provided. The diagnostic system is in communication with a plasma processing chamber of the plasma processing system and includes a diagnostic sensor to detect a plasma process condition. The diagnostic system is configured to substantially reduce contamination of the diagnostic sensor. The method includes substantially reducing contamination of the diagnostic sensor and detecting a condition of the plasma process and/or a substrate in the processing chamber.

Description

PLASMA PROCESSING SYSTEM AND METHOD

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and derives the benefit of U.S. Provisional Patent Application No. 60/414,349, filed September 30, 2002, the entire contents of which are incorporated herein by reference.

[0002] This application is related to U.S. Provisional Patent Application No. 60/414,348, "Apparatus and Method for Use of Optical System with a Plasma Processing System," Mitrovic et al., filed on September 30, 2002, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of Invention

[0003] The present invention relates to plasma processing and more particularly to reducing contamination of a diagnostic system used in plasma processing.

2. Description of Background Information

[0004] Typically, plasma is a collection of species, some of which are gaseous and some of which are charged. Plasmas are useful in certain processing systems for a wide variety of applications. For example, plasma processing systems are of considerable use in material processing and in the manufacture and processing of semiconductors, integrated circuits, displays and other electronic devices, both for etching and layer deposition on substrates, such as, for example, semiconductor wafers.

[0005] Diagnostic methods are widely used to monitor plasma processes and associated substrates and to determine an end point of a plasma process, for example, a plasma etching process. Diagnostic methods can include optical diagnostic methods or pressure measurement methods, for example. Maintenance is required when the diagnostic sensor becomes contaminated with plasma by- ^Λ products. SUMMARY OF THE INVENTION

[0006] One aspect of the invention is to provide a plasma processing system in communication with a diagnostic system. The plasma processing system comprises a chamber containing a plasma processing region, a chuck constructed and arranged to support a substrate within the chamber in the processing region and a chamber opening formed in a wall of the chamber to enable plasma within the plasma processing region to exit the chamber. A plasma generator is positioned in communication with the chamber and is constructed and arranged to generate a plasma during a plasma process in the plasma processing region. The diagnostic system includes a passageway formed between the plasma processing region and a diagnostic sensor. The passageway has a predetermined length and a predetermined diameter. The passageway is configured to have a length to diameter ratio, which is provided by dividing the predetermined length of the passageway by the predetermined diameter of the passageway, of at least 4.

[0007] Another aspect of the invention is to provide a method for operating a diagnostic system in communication with a plasma processing system. The plasma processing system has a chamber containing a plasma processing region in which a plasma can be generated during a plasma process and the diagnostic system. The diagnostic system monitors the plasma processing region and/or a substrate in the chamber. The method comprises providing a passageway formed between the plasma processing chamber and the diagnostic sensor with the passageway having a length to diameter ratio of at least 4. The method further comprises detecting an emission from the plasma processing region and/or substrate through an opening in the chamber and reducing contamination of the diagnostic system. Thus, a method can be provided to reduce contamination of a diagnostic system, e.g., an optical diagnostic assembly or a diagnostic assembly. [0008] In embodiments of the invention, the diagnostic system includes a contamination reducing structure which is configured to reduce contamination of the passageway associated with the diagnostic sensor. In one embodiment, the contamination reducing structure can include a gas purge passageway configured to introduce a purge gas into the passageway. In other embodiments, the contamination reducing structure can include an electric field generator, a magnetic field generator, a temperature controlled system, or a combination of at least two of an electric field generator, a magnetic field generator, a temperature controlled system and a gas purge passageway to reduce contamination of the passageway associated with the diagnostic sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings, which are incorporated in and constitute a part of the specification, of embodiments of the invention, together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention wherein:

[0010] FIG. 1 is a diagrammatic cross section of an embodiment of a plasma processing system in accordance with the principles of the invention, showing a plasma processing chamber in communication with a diagnostic system;

[0011] FIG. 2 is a diagrammatic cross section of a diagnostic system, which shows a pre-chamber area formed in the diagnostic system;

[0012] FIG. 3 is a diagrammatic cross section of a diagnostic system, which shows a temperature controlled system associated with the pre-chamber area;

[0013] FIG. 4 is a diagrammatic cross section of another embodiment of the diagnostic system, which shows an electric field generator associated with the pre- chamber area;

[0014] FIG. 5 is a diagrammatic cross section of another embodiment of the diagnostic system, which shows a magnetic field generator of the diagnostic system; [0015] FIG. 6 is a diagrammatic cross section taken through the line 6-6 of FIG. 5, which shows a polarization direction and magnetic field lines of the magnetic field generator shown in FIG. 5;

[0016] FIG. 7 is a diagrammatic cross section of another embodiment of the diagnostic system, which shows an alternative magnetic field generator of the diagnostic system;

[0017] FIG. 8 is a diagrammatic cross section taken through the line 8-8 of FIG. 7, which shows a polarization direction and magnetic field lines of the magnetic field generator shown in FIG. 7;

[0018] FIG. 9 is a diagrammatic cross section of another embodiment of the diagnostic system, which includes a passageway having a predetermined length and a predetermined diameter so to eliminate the pre-chamber area shown in FIG. 2;

[0019] FIG. 10 is a diagrammatic cross section of another embodiment of the diagnostic system, which shows a gas purge passageway operatively associated with the diagnostic system shown in FIG. 9;

[0020] FIG. 11 is a diagrammatic cross section of another embodiment of the diagnostic system, which shows a restrictor element restricting the passageway to have a predetermined length and a predetermined diameter;

[0021] FIG. 12 is a diagrammatic cross section of another embodiment of the restrictor element;

[0022] FIG. 13 is a diagrammatic cross section of another embodiment of the restrictor element, which shows a tapered configuration of the restrictor element which allows the restrictor outer diameter to increase or decrease along the passageway;

[0023] FIG. 14 is a diagrammatic cross section of another embodiment of the diagnostic system, which shows a gas purge passageway operatively associated with the diagnostic system shown in FIG. 1 1 ; [0024] FIG. 15 is a diagrammatic cross section of another embodiment of the diagnostic system, which shows a gas purge passageway operatively associated with the diagnostic system shown in FIG. 12;

[0025] FIG. 16 is a diagrammatic cross section of another embodiment of the diagnostic system, which shows a gas purge passageway operatively associated with the diagnostic system shown in FIG. 13; and

[0026] FIG. 17 is a flow chart showing a method of operating a diagnostic system in communication with a plasma processing system in accordance with principles of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0027] FIG. 1 shows an embodiment of a plasma processing system according to principles of the invention. The plasma processing system, generally indicated at 10, is in communication with a diagnostic system, generally indicated at 12. The diagnostic system 12 can be any diagnostic system, such as an optical diagnostic assembly, an imaging device viewport, a pressure sensor, a mass spectrometer, an ion flux and energy measurement system, or a plasma RF harmonic measurement system, for example.

[0028] The plasma processing system 10 comprises a plasma process chamber, generally indicated at 14, that defines a plasma processing region 16 in which a plasma 18 can be generated. A chuck or electrode 30 can be positioned in the chamber 14 and is constructed and arranged to support a substrate 20, which can be a semiconductor wafer, for example, within the chamber 14 in the processing region 16. The substrate 20 can be a semiconductor wafer, integrated circuit, a sheet of a polymer material to be coated, a metal to be surface hardened by ion implantation, or some other semiconductor material to be etched or deposited, for example.

[0029] Although not shown, coolant can be supplied to the chuck 30, for example, through cooling supply passages coupled to the chamber 14. Each cooling supply passage can be coupled to a cooling supply source. For example, the cooling supply passages can be individually connected to the cooling supply source. Alternatively, cooling supply passages can be interconnected by a network of interconnecting passages, which connect all cooling supply passages in some pattern.

[0030] Generally, plasma generation gas, which can be any gas that is ionizable to produce a plasma, is introduced into the chamber 14 to be made into a plasma, for example, through a gas inlet 26. The plasma generation gas can be selected according to the desired application as understood by one skilled in the art and can be nitrogen, xenon, argon, carbon tetrafluoride (CF4) or octafluorocyclobutane

(C4Fg) for fluorocarbon chemistries, chlorine (Cl₂), hydrogen bromide (HBr), or oxygen (O₂) for example.

[0031] The gas inlet 26 is coupled to the chamber 14 and is configured to introduce plasma processing gases into the plasma processing region 16. A plasma generator in the form of upper electrode 28 and lower electrode 30 can be coupled to the chamber 14 to generate the plasma 18 within the plasma processing region 16 by ionizing the plasma processing gases. The plasma processing gases can be ionized by supplying RF and/or DC power thereto, for example. In some applications, the plasma generator can be an antenna or RF coil capable of supplying RF power, for example.

[0032] A variety of gas inlets or injectors and various gas injecting operations can be used to introduce plasma processing gases into the plasma processing chamber 14, which can be hermetically sealed and can be formed from aluminum or another suitable material. The plasma processing gases are often introduced from gas injectors or inlets located adjacent to or opposite from the substrate. For example, as shown in FIG. 1, gases supplied through the gas inlet 26 can be injected through an inject electrode (upper electrode 28) opposite the substrate in a capacitively coupled plasma (CCP) source. The power supplied to the plasma can ignite a discharge with the plasma generation gas introduced into the chamber 14, thus generating a plasma, such as plasma 18.

[0033] Alternatively, in embodiments not shown, the gases can be injected through a dielectric window opposite the substrate in a transformer coupled plasma (TCP) source. Other gas injector arrangements are known to those skilled in the art and can be employed in conjunction with the plasma processing chamber 14.

[0034] The plasma processing chamber 14 is fitted with an outlet having a first vacuum pump 32 and a valve 34, such as a throttle control valve, to provide gas pressure control in the plasma process chamber 14.

[0035] Various leads (not shown), for example, voltage probes or other sensors, can be coupled to the plasma processing system 10.

[0036] An opening 22 extends radially from the process chamber 14 through a chamber wall 36 to the diagnostic system 12. Generally, in diagnostic assemblies having pressure sensors or mass spectrometers, the opening 22 can be made large to allow faster sensor response. In optical diagnostic assemblies, the opening 22 can be made large to allow a stronger signal or signals to be transmitted to and collected by the optical diagnostic assembly or detector.

[0037] The diagnostic system 12 is generally vacuum tight and can be formed in communication with the process chamber 14 to enable communication with the plasma processing region 16, as will be described in further detail below.

[0038] A gate valve (not shown) can be coupled to the plasma process chamber 14, adjacent to the chamber opening 22 and between the plasma process chamber 14 and the diagnostic system 12. The gate valve can be provided to allow isolation of the diagnostic system 12 from the plasma processing chamber 14 for maintenance operations, such as calibrating or recalibrating sensors in a diagnostic assembly, cleaning a window in an optical diagnostic assembly, replacing the window in an optical diagnostic assembly or periods of gas purge, for example. The gate valve is not essential to the invention and is omitted from the embodiment shown in FIG. 1. The gate valve can be provided or eliminated from the system 10 depending on the plasma process being performed by the system 10.

[0039] As shown in FIG. 2, one embodiment of the diagnostic system 12 includes a mounting portion 38 and a diagnostic sensor 40. The mounting portion 38 of the diagnostic system 12 can be coupled to the chamber wall 36 of the plasma process chamber 14 by a mounting flange 42 (or a plurality of the same). Fasteners (not shown), such as nuts and bolts, or screws, for example, can extend through the mounting flange 42 to couple the mounting flange 42 to the chamber wall 36. One or more mounting walls 44, which can have a tubular or cylindrical configuration, can extend from the mounting flange 42. End portions 48 can extend outwardly from the mounting walls 44 to couple the diagnostic sensor 40 thereto, as shown in FIG. 2. Alternatively, the mounting flange 42 and the mounting walls 44 can be formed in other configurations as well.

[0040] As shown in FIGS. 1 and 2, the mounting walls 44 can define a passageway 46 having a selected diameter therein in a longitudinal direction thereof. The passageway 46 is configured to allow communication between the plasma processing chamber 14 and the diagnostic sensor 40 of the diagnostic system 12 (as indicated by an arrow labeled A in FIG. 1). The diameter of the passageway 46 can be substantially the same as, smaller than or larger than the diameter of the opening 22 to allow transmission to the diagnostic sensor 40.

[0041] A flow restrictor element 50 can be mounted within the mounting walls 44 of the diagnostic system 12, by adhesive, bonding material or other suitable fasteners, to determine the amount of light or gas that reaches the diagnostic sensor 40 (e.g., by restricting the flow through the opening 22 formed in the chamber wall 36). The restrictor element 50 extends between the diagnostic sensor 40 and the plasma processing region 16. The diameter of the passageway 46 is effectively determined by the size of the restrictor element 50. The restrictor element 50 can be integrally formed with the mounting portion 38. That is, rather than having a separate restrictor element, the inner wall of mounting portion 38 inherently defines a restrictor.

[0042] The flow restrictor element 50, the mounting portion 38 or both the flow restrictor element 50 and the mounting portion 38 can be made from metals, e.g., aluminum, anodized aluminum and stainless steel, dielectric materials, e.g., ceramics such as quartz, alumina, silicon-carbide and silicon-nitride, semiconductor materials, e.g., silicon, doped silicon and other materials. For example, in plasma processes involving aggressive chemistries, such as fluorine-based chemistries, a flow restrictor element made from semiconductor materials, e.g., silicon, can reduce the concentration of aggressive species.

[0043] The mounting walls 44 can also optionally include a gas purge passageway 54 coupled thereto for communication with a pre-chamber area 52, formed between the restrictor element 50 and the diagnostic sensor 40. The gas purge passageway 54 can be integrally formed with the mounting walls 44, as shown in FIG. 2, or alternatively, can be coupled thereto with fasteners (not shown), such as nuts and bolts, or screws, for example.

[0044] The gas purge passageway 54 allows a purge gas to be provided to the pre- chamber area 52, for example (as indicated by an arrow labeled B in FIG. 2). When purge gas is provided to the pre-chamber area 52, a pressure within the pre-chamber area 52 is increased relative to a pressure in the plasma processing region 16, thus creating a pressure difference between the pre-chamber area 52 and the plasma processing region 16. The pressure difference establishes a flow from the pre- chamber area 52 to the plasma processing chamber 14 (as indicated by an arrow labeled C in FIG. 2), which reduces upstream diffusion of contaminants, e.g., plasma-borne chemical species, from the plasma 18 to the diagnostic sensor 40. The diameter size of the passageway 46 in combination with the pressure difference and established flow between the pre-chamber area 52 and the plasma processing region 16, also reduces plasma light-up in the pre-chamber area 52. For example, the restrictor element 50 can be sized to provide the passageway 46, which can have a diameter selected from the range of 0.1 cm to 2.5 cm, for example. The diameter of the passageway 46 can be smaller than the diameter of the opening 22 to help reduce contaminant backflow and plasma lightup.

[0045] In plasma processes that do not involve aggressive chemistry, the gas purge passageway 56 and the flow restrictor element 50 may be eliminated from the diagnostic system 12. This is because contamination of the diagnostic system 12, e.g., the passageway 46 or the diagnostic sensor 40, is greater in processes that involve aggressive chemistry, and with non-aggressive chemistry there is no need to restrict the flow or use purge gas. [0046] A spectrometer (not shown) can be incorporated in the diagnostic sensor 40 to detect a plasma process condition based on an optical emission, e.g., light, from the plasma 18, or may be separate from the sensor 40. The spectrometer or the detector system can be associated with a photomultiplier tube, a CCD or other solid state detector to at least partially detect the plasma process condition, such as an endpoint of a plasma process, for example. However, other optical devices capable of analyzing an optical emission or properties of a wafer, e.g., films associated with the wafer, can be used as well.

[0047] A controller 56 capable of generating control voltages sufficient to communicate and activate inputs to plasma processing system 10 as well as capable of monitoring outputs from the plasma processing system 10 can be coupled to the plasma processing system 14. For example, the controller 56 can be coupled to and can exchange information with the upper electrode 28, the lower electrode 30 and the gas inlet 26. A program, which can be stored in a memory, can be utilized to control the aforementioned components of plasma processing system 10 according to a stored process recipe. Furthermore, controller 56 is capable of controlling the components of the diagnostic system 12. For example, the controller 56 can be configured to control the diagnostic sensor 40. Alternatively, multiple controllers 56 can be provided, each of which being configured to control different components of either the plasma processing system 10 or the diagnostic system 12, for example. One example of the controller 56 is an embeddable PC computer type PC/104 from Micro/SYS of Glendale, CA.

[0048] FIG. 3 shows a diagnostic system 112, which is an alternative embodiment of the diagnostic system 12. Elements in the diagnostic system 112 that are similar to elements of the diagnostic system 12 have corresponding reference numerals. The passageway 46, the restrictor element 50, the pre-chamber area 52 and the gas purge passageway 54 can be employed in a substantially identical manner as set forth above with respect to diagnostic system 12. However, the gas purge passageway 54 can be omitted depending on the plasma process application.

[0049] The diagnostic system 112 includes a mounting portion 138, which can be made from the same materials as the mounting portion 38 described above. The mounting portion 138 has a mounting flange 142 (or a plurality of the same) with fasteners (not shown) to couple the mounting flange 142 to the chamber wall 36. A plurality of mounting walls 144a, 144b, which can have a tubular or cylindrical configuration, can extend from the mounting flange 142. The mounting walls 144a, 144b form a fluid chamber 143 therebetween. The fluid chamber 143 can have a tubular or cylindrical configuration and can be in communication with a fluid inlet 158, which is coupled to the outer mounting wall 144b. The fluid inlet 158 is configured to carry fluid, e.g., gas or liquid, to the fluid chamber 143. A fluid outlet 160 is coupled to the mounting wall 144b in communication with an opposite end of the fluid chamber 143 from the fluid inlet 158. The fluid inlet 158 or the fluid outlet 160 can be integral with the wall portion 144b or can be fastened to the wall portion 144b on opposite sides of the passageway 46 with suitable fasteners. The fluid inlet 158 and the fluid outlet 160 can be positioned anywhere along the mounting wall 144b. For example, the fluid inlet 158 can be provided adjacent the gas purge passageway 54 and the fluid outlet 160 can be provided on the opposite side of the passageway 46 or vice versa.

[0050] Depending on the plasma process application, a temperature of the fluid introduced into the fluid chamber 143 can be selected, e.g., an elevated temperature (e.g., 250°C) or a reduced temperature(e.g., -196°C), with respect to a gas temperature inside of the pre-chamber area 52 and the passageway 46. An elevated temperature can generally reduce film contamination in some plasma chemistries, while a reduced temperature, e.g., cryogenic, can cause rapid adsorption of contaminants in the plasma in the passageway 46 so that contaminants do not reach the diagnostic sensor 40. Thus, the fluid temperature can be controlled and selected to help reduce contamination of the diagnostic sensor 40.

[0051] To provide elevated temperatures, the wall portion 144b and the chamber 143 can be replaced with a heater, e.g., an electric heater, wrapped around an outer periphery of the wall portion 144a. Alternatively, the heater could be implemented in combination with the wall portion 144b and the fluid chamber 143.

[0052] FIG. 4 shows a diagnostic system 212, which is an alternative embodiment of the diagnostic systems 12, 112. Elements in the diagnostic system 212 that are similar to elements of the diagnostic systems 12, 112 have corresponding reference numerals. The passageway 46, the restrictor element 50, the pre-chamber area 52 and the gas purge passageway 54 can employed in a substantially identical manner as set forth above with respect to diagnostic systems 12, 112. However, the gas purge passageway 54 can be omitted depending on the plasma process application.

[0053] The diagnostic system 212 includes a mounting portion 238, which can be made from the same materials as the mounting portion 38 described above. The mounting portion 238 has a mounting flange 242 (or a plurality of the same) with fasteners (not shown) to couple the mounting flange 242 to the chamber wall 36. A mounting wall 244, which can have a tubular or cylindrical configuration, can extend from the mounting flange 242. The mounting wall 244 is configured to receive an insulator 262, such as silica (quartz), alumina or another dielectric material, and an electric field generator 264 mounted thereto, e.g., by fasteners, adhesive, bonding material or other suitable fasteners. The insulator 262 insulates an outer portion of the electric field generator 264.

[0054] The mounting wall 244 can have an opening 266 formed therein for receiving a feedthrough element 268. The feedthrough element 268 couples the electric field generator 264, which can include an annular electrode or a plurality of electrodes, with a power supply 270. The power supply 270 can supply either DC or radio frequency (RF) bias power to the electric field generator 264.

[0055] Depending on the plasma process application, either DC or RF biased power can be used to repel plasma from the passageway 46. For example, a strong negative DC bias at moderate to high pressures, e.g., pressures equal to or greater than about 40 mTorr, can substantially reduce plasma in the processing chamber 14 from entering the pre-chamber 52 and the passageway 46 or vicinities thereof by repelling electrons in the plasma from the passageway 46. Other electrodes can be used to provide the DC or RF power such that the electrode can be biased to the same charge of the plasma charged species to repel those species (e.g., a positive electrode can be used to repel ions in the plasma). In other words, a "standing-off ' effect is provided, in which the plasma is confined to an area outside the passageway 46 or a vicinity thereof. At the moderate to high pressures, ions in the plasma can frequently collide with other particles in the plasma to further reduce plasma light- up within the passageway 46 or a vicinity thereof.

[0056] FIG. 5 shows a diagnostic system 312, which is an alternative embodiment of the diagnostic systems 12, 112, 212. Elements in the diagnostic system 312 that are similar to elements of the diagnostic systems 12, 112, 212 have corresponding reference numerals. The passageway 46, the restrictor element 50, the pre-chamber area 52 and the gas purge passageway 54 can employed in a substantially identical manner as set forth above with respect to diagnostic systems 12, 112. However, the gas purge passageway 54 can be omitted depending on the plasma process application.

[0057] The diagnostic system 312 includes a mounting portion 338, which can be made from the same materials as the mounting portion 38 described above. The mounting portion 338 has a mounting flange 342 (or a plurality of the same) with fasteners (not shown) to couple the mounting flange 342 to the chamber wall 36. A mounting wall 344, which can have a tubular or cylindrical configuration, can extend from the mounting flange 342. The mounting wall 344 has an opening 372 formed therein, which is configured to receive a magnetic field generator 376 and a magnetic field leakage reducing member 374 therein. The magnetic field generator 376, which can include one or more permanent magnets or current-carrying coils, is configured to produce a magnetic field (generally indicated at 378 in FIG. 6) across the passageway 46. The magnetic field generator 376 can be mounted within the opening 372 of the mounting wall 344 along with the magnetic field leakage reducing member 374 by fasteners, adhesive, bonding material or other suitable fasteners, for example.

[0058] The magnetic field leakage reducing member 374 can be an iron ring, for example, or any other structure capable of reducing leakage of the magnetic field outside the passageway 46. Thus, the possibility of the magnetic field 378 affecting the plasma process within the plasma processing chamber 14, and the diagnostic system 40, can be reduced. [0059] Depending on the plasma process application, the magnetic field generator 376 can be configured to form the magnetic field 378 across the passageway such that plasma is substantially prevented from entering the pre-chamber 52 and the passageway 46 or vicinities thereof. In other words, the magnetic field 378 can shield plasma generally outside (within the plasma processing chamber 14) the passageway 46.

[0060] FIG. 6 shows a cross-sectional view of the mounting wall 344, the magnetic field leakage reducing member 374 and the magnetic field generator 376 in which one example of the magnetic field 378 is shown across the passageway 46. The restrictor element 50 is eliminated from FIG. 6 for simplicity. As illustrated, the magnetic field generator 376 includes a plurality of permanent magnets 380 positioned circumferentially around the passageway 46 to form a dipole ring. In this example, the magnets 380 are positioned relative to one another such that adjacent magnets 380 have polarization directions 382 (shown as bolded arrows) successively directed in a counter-clockwise direction. Although not shown, the magnets 380 can be oriented to be symmetric with respect to a horizontal axis (shown as a dotted line in FIG. 6). FIG. 6 shows 16 magnets 380, each having a polarization direction 382 that is separated from the polarization direction 382 of an adjacent magnet 380 by about 45°. However, other magnetic configurations are possible, e.g., when more or less magnets 380 are implemented, and the separation angle is changed accordingly, e.g., the angle between adjacent magnet polarization directions is twice the separation angle between the magnets.

[0061] The configuration of magnets 380 shown in FIG. 6 produces the magnetic field 378, which has field lines 384 that extend across the passageway 46. In the magnetic field 378, particles readily spiral along the field lines 384 and only slowly diffuse across the field lines 384 and into the passageway 46, which helps to shield the passageway 46 or a vicinity thereof from plasma.

[0062] FIG. 7 shows a diagnostic system 412, which is an alternative embodiment of the diagnostic systems 312. The diagnostic system 412 is substantially identical in construction and operation as the diagnostic system 312, but includes a magnetic field generator 476, which is an alternative embodiment of the magnetic field generator 376. Although not shown in this embodiment, the magnetic field leakage reducing member 374 could be positioned around the magnetic field generator 476, as described above with respect to the magnetic field generator 376.

[0063] The diagnostic system 412 includes a mounting portion 438, which can be made from the same materials as the mounting portion 38 described above. The mounting portion 438 has the mounting flange 342 (or a plurality of the same) and the mounting wall 344 described above. The magnetic field generator 476 can be mounted within the opening 372 by appropriate mounting elements.

[0064] FIG. 8 shows the magnetic field generator 476 including a plurality of permanent magnets 480 positioned circumferentially around the passageway 46. Each magnet 480 has a polarization direction 482 directed radially inward toward the passageway 46 (as shown in FIG. 8) or directed outward away from the passageway 46. However, more or less magnets 480 can be provided and other magnetic configurations are possible, e.g., the polarization direction 482 of each magnet 480 can be alternated between adjacent magnets 480, e.g., one magnet can have a polarization direction directed radially inward and adjacent magnets can have a polarization direction directed radially outward, or vice versa.

[0065] The configuration of magnets 480 shown in FIG. 8 produces the magnetic field 478, which has field lines 484, which extend into the passageway 46. Depending on the plasma process application, the magnetic field 478 can be formed such that plasma entering the pre-chamber 52 and the passageway 46 or vicinities thereof is substantially reduced. In other words, the magnetic field 478 can at least partially shield plasma from entering the pre-chamber 52 and the passageway 46 or vicinities thereof.

[0066] The magnetic field 478 is less strong than the magnetic field 378 described above because the field strength at the center of the passageway 46 is zero. However, with its lesser strength, the magnetic field 478 can be used in plasma processes in which strong magnetic fields induce undesirable effects, which can affect measurement, e.g., providing a pumping effect on the plasma that affects pressure measurements. [0067] With respect to FIGS. 6 and 8, alternate configurations of the magnetic fields 378, 478 are possible and can be formed by providing multiple rows of magnets 380, 480, respectively, with the same or alternating polarization directions 382, 482 to achieve other different field configurations, for example.

[0068] In the above embodiments, shown in FIGS. 2-5 and 7, the gas purge passageway 56 is provided to supply a purge gas into the passageway 46 and the pre-chamber area 52. As described above, the supply of purge gas can reduce backflow of chamber process gas into the passageway, which reduces contamination of the diagnostic sensor 40. The gas purge passageway 56 supplied purge gas into the passageway 46 and the pre-chamber area 52 so as to not disturb existing chamber gas flow significantly, e.g., the purge gas flow should not create a disturbing gas jet that extends far into the chamber 14.

[0069] FIGS. 9-16 show diagnostic systems that are alternative embodiments of the diagnostic system 12. The diagnostic systems shown in FIGS. 9-16 each includes a flow restriction having a length to diameter ratio of at least 4 to reduce backflow of chamber process gas into the passageway and to reduce contamination of the diagnostic sensor. In each of the below described diagnostic systems, the chamber wall has a thickness that is less than the predetermined length of the passageway.

[0070] FIG. 9 shows a diagnostic system 512 that is an alternative embodiment of the diagnostic system 12, which operates in substantially the same manner as the diagnostic system 12. The diagnostic system 512 includes a mounting portion 538, which can be made from the same materials as the mounting portion 38 described above. The mounting portion 538 has a mounting wall 544 coupled to the chamber wall 36 by one or more fasteners 537. The fastener(s) may be one or more of a seal, an O-ring or any other type of sealing fastener capable of coupling the mounting wall 744 to the chamber wall 36.

[0071] A diagnostic sensor, which is not shown for simplicity, can be operatively associated with the diagnostic system 512. The diagnostic sensor can operate in substantially the same manner as the sensor 40 shown in FIG. 1 and can be operatively associated with a diagnostic sensor element 539. The diagnostic sensor element 539, which can be a window or diagnostic aperture, for example, can be coupled to the mounting wall 544. Because the diagnostic sensor element 539 is directly mounted onto the mounting wall 544, the diagnostic system 512 does not include a pre-chamber area.

[0072] The mounting wall 544 has an interior surface 545 that defines a passageway 546 having a predetermined diameter D. The diameter D of the passageway 546 can be equal to, smaller or larger than the diameter of the opening 22 formed in the chamber wall 36.

[0073] The passageway 546 has a predetermined length L, which can be defined in this embodiment as the distance from the chamber opening 22 to the diagnostic sensor element 539 or to the diagnostic sensor. The length L can be selected to be longer than the gas mean free path of molecules of a contaminant at the selected process conditions, e.g., processing chamber pressure, chamber gas flow and chamber gas temperature. Because the length L of the passageway 546 is selected to be X times longer than the gas mean free path of contaminant molecules at the selected process conditions, a contaminant molecule will generally experience X number of collisions on its way through the passageway 546. Thus, the number of contaminant molecules that reach the diagnostic sensor or the diagnostic sensing element 539 is reduced, at least partially due to the X number of collisions. In this conceptual example, X may represent a number greater than zero, e.g., 25, 55, 85 or higher. However, X can be selected to be any number depending on the gas mean free path of contaminant molecules and the selected process conditions, which can vary depending on the plasma process.

[0074] The length L and the diameter D of the passageway 546 can be selected to provide a length to diameter ratio (L/D) of at least 4, which can be obtained by dividing the length L of the passageway by the diameter D of the passageway 546. The passageway 546 can be configured to provide length to diameter ratios greater than 4 depending on the plasma process being used or process characteristics, e.g., processing chamber pressure, chemistry, gas flow, and temperature, thereof. [0075] FIG. 10 shows a diagnostic system 612, which has substantially the same construction as the diagnostic system 512, but includes a gas purge passageway 556. The diagnostic system 612 includes a passageway 646, which is substantially similar in operation as the passageway 56 in FIG. 2 and the passageway 556 in FIG. 9. The passageway 646 has a length L defined in this embodiment as the distance from the chamber opening 22 to the gas purge passageway 556. As discussed above, the length L of the passageway 646 can be selected to be longer than the gas mean free path of contaminant molecules at the selected process conditions.

[0076] The gas purge passageway 556 operates in substantially the same manner as the gas purge passageway 56 described above with respect to FIG. 2. The above description of other elements of the diagnostic system 512 (as shown in FIG. 9) will not be repeated with respect to FIG. 10 for simplicity.

[0077] The diameter D of the passageway 646 can be equal to, smaller or larger than the diameter of the opening 22 formed in the chamber wall 36.

[0078] The length L and the diameter D of the passageway 646 are selected to provide a length to diameter ratio (L/D) of at least 4, which can be obtained by dividing the length L of the passageway by the diameter D of the passageway 646. The passageway 646 can be configured to provide length to diameter ratios greater than 4 depending on the plasma process being used process characteristics, e.g., processing chamber pressure, chamber gas flow and chamber gas temperature, thereof. The gas purge passageway 646 helps further reduce contamination of the diagnostic sensing element 539 (and in turn the diagnostic sensor).

[0079] FIG. 11 shows a diagnostic system 712 that is an alternative embodiment of the diagnostic system 512, which operates in a substantially similar manner as the diagnostic system 512. The diagnostic system 712 has a substantially similar construction as the diagnostic system 512 shown in FIG. 9, but includes a flow restrictor element 550 positioned along the interior surface 545 of the mounting wall 544.

[0080] The flow restrictor element 550, which may be made from the same materials as the flow restrictor element 50 described above, extends along the interior surface 545 of the mounting wall 544 from the chamber opening 22 to the diagnostic sensor element 539 or to the diagnostic sensor. The flow restrictor element 550 has an interior surface 555 that defines a passageway 746 having a predetermined diameter D. The diameter D of the passageway 746 can be equal to, smaller or larger than the diameter of the opening 22 formed in the chamber wall 36. As illustrated, the diameter D of the passageway 746 is smaller than the opening 22.

[0081] The passageway 746 has a predetermined length L, which can be defined in this έmbodiment as the distance from the chamber opening 22 to the diagnostic sensor element 539 or to the diagnostic sensor. As discussed above, the length L of the passageway 746 can be selected to be longer than the gas mean free path of contaminant molecules at the selected process conditions.

[0082] The length L and the diameter D of the passageway 746 are selected to provide a length to diameter ratio (L/D) of at least 4, which can be obtained by dividing the length L of the passageway by the diameter D of the passageway 746. The passageway 746 can be configured to provide length to diameter ratios greater than 4 depending on the plasma process being used or process characteristics, e.g., processing chamber pressure, chamber gas flow and chamber gas temperature, thereof.

[0083] FIG. 12 shows a diagnostic system 812, which is an alternative embodiment of the diagnostic system 712. The diagnostic system 812 operates in a substantially similar manner as the diagnostic system 712 shown in FIG. 9, but includes a flow restrictor element 650 having an end portion 639 configured to abut a recessed portion 637 of a chamber wall 636.

[0084] The diagnostic system 812 provides another way to implement a flow restrictor element into a diagnostic system. Specifically, in the diagnostic system 812, an end portion 639 of the flow restrictor element 650 is configured to abut a recessed portion 637 formed in the chamber wall 636.

[0085] The flow restrictor element 650, which may be made from the same materials as the flow restrictor element 50 described above, extends from the recessed portion 637, which is adjacent to the chamber opening 22, to the diagnostic sensor element 539 or to the diagnostic sensor. The flow restrictor element 650 defines a passageway 846 having a predetermined diameter D. The diameter D of the passageway 846 can be equal to, smaller or larger than the diameter of the opening 22 formed in the chamber wall 36. As illustrated, the diameter D of the passageway 846 is smaller than the opening 22.

[0086] The passageway 846 has a predetermined length L, which can be defined in this embodiment as the distance from the end portion 637 of the flow restrictor element 650 to the diagnostic sensor element 539 or to the diagnostic sensor. As discussed above, the length L of the passageway 846 can be selected to be longer than the gas mean free path of contaminant molecules at the selected process conditions.

[0087] The length L and the diameter D of the passageway 846 are selected to provide a length to diameter ratio (L/D) of at least 4, which can be obtained by dividing the length L of the passageway by the diameter D of the passageway 846. The passageway 846 can be configured to provide length to diameter ratios greater than 4 depending on the plasma process being used or process characteristics, e.g., processing chamber pressure, chamber gas flow and chamber gas temperature, thereof.

[0088] FIG. 13 shows a diagnostic system 912 that is an alternative embodiment of the diagnostic system 512, which operates in a substantially similar manner as the diagnostic system 512. The diagnostic system 912 has a substantially similar construction as the diagnostic system 512 shown in FIG. 9, but includes a tapered flow restrictor element 750 positioned along a tapered interior surface 745 of a mounting wall 744.

[0089] The diagnostic system 912 includes a mounting portion 738, which can be made from the same materials as the mounting portion 38 described above. The mounting portion 738 has the tapered mounting wall 744 coupled to the chamber wall 36 by one or more fasteners 537. The fastener(s) may be one or more of a seal, an O-ring or any other type of sealing fastener capable of coupling the mounting wall 744 to the chamber wall 36. [0090] The flow restrictor element 750, which may be made from the same materials as the flow restrictor element 50 described above, extends along the interior surface 745 of the mounting wall 744 from the chamber opening 22 to the diagnostic sensor element 539 or to the diagnostic sensor. The flow restrictor element 750 has a tapered outer surface 755, which abuts the opening in the chamber wall 36 to help support the flow restrictor element 750 within the chamber wall 36. The flow restrictor element 750 defines a passageway 946 having a predetermined diameter D. The diameter D of the passageway 946 can be equal to, smaller or larger than the diameter of the opening 22 formed in the chamber wall 36.

[0091] As illustrated, the diameter D of the passageway 946 is smaller than the opening 22 and is constant along the length L thereof. However, the passageway 946 can have a variable diameter configured to increase or decrease along the passageway 946. For example, the diameter D of the passageway 946 can incrementally increase in a direction toward the diagnostic sensor element 539 or to the diagnostic sensor, as shown in FIG. 13. Alternatively, the diameter D of the passageway 946 can incrementally decrease in a direction toward the diagnostic sensor element 539 or to the diagnostic sensor.

[0092] The passageway 946 has a predetermined length L, which can be defined in this embodiment as the distance from the chamber opening 22 to the diagnostic sensor element 539 or to the diagnostic sensor. As discussed above, the length L of the passageway 946 can be selected to be longer than the gas mean free path of contaminant molecules at the selected process conditions.

[0093] The length L and the diameter D of the passageway 946 are selected to provide a length to diameter ratio (L/D) of at least 4, which can be obtained by dividing the length L of the passageway by the diameter D of the passageway 946. The passageway 946 can be configured to provide length to diameter ratios greater than 4 depending on the plasma process being used or process characteristics, e.g., processing chamber pressure, chamber gas flow and chamber gas temperature, thereof. In passageways having a variable diameter D, an average diameter along a length L thereof can be used to provide the length to diameter ratio (L/D) of at least 4. [0094] FIG. 14 shows a diagnostic system 1012, which has substantially the same construction as the diagnostic system 712, but includes the gas purge passageway 556. The diagnostic system 1012 also includes the passageway 746, which has a length L defined as the distance from the chamber opening 22 to the gas purge passageway 556. As discussed above, the length L of the passageway 746 can be selected to be longer than the gas mean free path of contaminant molecules at the selected process conditions.

[0095] FIG. 15 shows a diagnostic system 1112, which has substantially the same construction as the diagnostic system 812, but includes the gas purge passageway 556. The diagnostic system 1112 also includes the passageway 846, which has a length L defined as the distance from the end portion 637 of the flow restrictor element 650 to the gas purge passageway 556. As discussed above, the length L of the passageway 846 can be selected to be longer than the gas mean free path of contaminant molecules at the selected process conditions.

[0094] FIG. 16 shows a diagnostic system 1212, which has substantially the same construction as the diagnostic system 912, but includes the gas purge passageway 556. The diagnostic system 1212 also includes the passageway 946, which has a length L defined as the distance from the chamber opening 22 to the gas purge passageway 556. As discussed above, the length L of the passageway 946 can be selected to be longer than the gas mean free path of contaminant molecules at the selected process conditions.

[0095] Although a passageway having a variable diameter D is only described in relation to the passageway 946, other passageways, e.g., passageways 46, 546, 646, 746 and 846, described herein can also be configured to have a variable diameter, e.g., increasing or decreasing along a length of the passageway.

[0096] FIG. 17 shows a method in accordance with principles of the invention. The method is for operating a diagnostic system in conjunction with a plasma processing system. The plasma processing system has a chamber containing a plasma processing region in which a plasma can be generated during a plasma process and the diagnostic system is positioned in an optical diagnostic chamber coupled to the plasma processing region.

[0097] The method starts at 1300. At 1302, contamination of a diagnostic sensor is substantially reduced. The backflow of contaminants from the plasma processing chamber through the passageway (and a pre-chamber area, if provided) to the diagnostic sensor associated with the plasma processing system can be substantially reduced. For example, the plasma is substantially shielded from entering the passageway (and a pre-chamber area, if provided) formed in the diagnostic system between the diagnostic system and the plasma processing chamber or vicinities thereof. A purge gas can be introduced into the pre-chamber area for substantially shielding the plasma from entering the passageway and the pre-chamber area. The method can comprise acts, operations or procedures, such as, for example, providing a heating element, a cooling element, an electric field, or a magnetic field, in combination or separately, to reduce contamination of the pre-chamber and passageway connecting the pre-chamber and the plasma processing chamber. Various combinations of these additional acts, operations or procedures could be used as well. For example, a diagnostic system could employ a magnetic field and an electric field, in combination with or separate from, the purge gas to shield plasma from entering the pre-chamber and the passageway.

[0098] At 1304, a condition of the plasma process is detected by a diagnostic system capable of receiving the condition, e.g., light, gas or pressure, from the plasma processing region and/or the substrate. For example, a plasma processing condition, such as an endpoint of the plasma process, can be detected using the diagnostic system. At 1306, the method ends.

[0099] One such method to detect a plasma process condition through an optical window is disclosed in U.S. Application of Mitrovic et al., Attorney Docket 291738, filed concurrently herewith, the contents of which are incorporated by reference herein in their entirety.

[0100] While the present invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details can be made therein without departing from the spirit and scope of the invention.

[0100] For example, the system 12 can be used with substantially all diagnostic systems with only slight modifications for the introduction of laser beams for diagnostic purposes or materials processing, into a processing chamber. The system 12 can be associated with one or more RF probes or antennas configured to monitor harmonic content of the plasma. For example, one or more RF probes can be mounted outside the plasma processing chamber 14, e.g., to replace or in conjunction with the diagnostic sensor 40, to monitor RF energy from the plasma processing chamber 14 and analyze harmonic content thereof.

[0101] Thus, the foregoing embodiments have been shown and described for the purpose of illustrating the functional and structural principles of this invention and are subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.

Claims

What is claimed is:

1. A plasma processing system comprising: a processing chamber having an opening formed in a wall thereof and containing a plasma processing region; a chuck, constructed and arranged to support a substrate within the chamber in the processing region; a plasma generator in communication with the chamber, the plasma generator being constructed and arranged to generate a plasma during a plasma process in the plasma processing region; and a diagnostic system having a diagnostic sensor in communication with the chamber and being constructed and arranged to substantially reduce contamination of the diagnostic sensor, the diagnostic system including a passageway formed between the plasma processing region and the diagnostic sensor and having a predetermined length and a predetermined diameter, wherein the passageway has a length to diameter ratio, provided by dividing the predetermined length by the predetermined diameter, of at least 4.

2. The plasma processing system of claim 1 , wherein the diagnostic system is constructed and arranged to detect a plasma process and/or substrate condition associated with the chamber.

3. The plasma processing system of claim 1 , wherein the diagnostic system includes a restrictor element positioned in the passageway.

4. The plasma processing system of claim 3, wherein the restrictor element is positioned adjacent the opening in the chamber.

5. The plasma processing system of claim 3, wherein the restrictor element is configured to abut a recessed portion of the chamber.

6. The plasma processing system of claim 3, wherein the restrictor element has a tapered outer surface.

7. The plasma processing system of claim 1, wherein the diagnostic system includes a purge gas port in communication with the passageway, the purge gas port being capable of supplying a purge gas to purge the passageway.

8. The plasma processing system of claim 7, wherein the restrictor element is configured to create a higher pressure of purge gas passed through the passageway due to reduced flow conductance.

9. The plasma processing system of claim 1 , wherein the diagnostic sensor is constructed and arranged to detect a plasma process and/or a substrate condition associated with the plasma processing region.

10. The plasma processing system of claim 9, wherein the diagnostic sensor includes an optical assembly.

11. The plasma processing system of claim 9, wherein the plasma process condition is an endpoint of the plasma process.

12. The plasma processing system of claim 1, further comprising an electric field generator configured to produce an electric field at least in the passageway or a vicinity thereof adjacent to the plasma processing chamber.

13. The plasma processing system of claim 12, wherein the electric field generator comprises an electrode assembly having at least one electrode.

14. The plasma processing system of claim 12, further comprising an insulator substantially surrounding the electric field generator.

15. The plasma processing system of claim 14, further comprising a power supply coupled to the electric field generator to supply power to the electric field generator.

16. The plasma processing system of claim 15, wherein the power is DC or RF biased power.

17. The plasma processing system of claim 1 , further comprising a magnetic field generator configured to produce a magnetic field at least in the passageway or a vicinity thereof adjacent to the plasma processing chamber.

18. The plasma processing system of claim 17, further comprising a magnetic field leakage reducing member substantially surrounding the magnetic field generator.

19. The plasma processing system of claim 17, wherein the magnetic field generator comprises a plurality of magnets.

20. The plasma processing system of claim 19, wherein the plurality of magnets is positioned around the passageway such that each magnet of the plurality of magnets has a polarization direction separated from a polarization direction of an adjacent magnet by twice the separation angle between the magnets.

21. The plasma processing system of claim 19 wherein the plurality of magnets is positioned around the passageway such that each magnet of the plurality of magnets has a polarization direction directed in the same radial direction.

22. The plasma processing system of claim 19 wherein the plurality of magnets is positioned around the passageway such that alternate magnets of the plurality of magnets have a polarization direction directed in opposite radial directions.

23. The plasma processing system of claim 17, wherein the magnetic field generator comprises at least one current-carrying coil.

24. The plasma processing system of claim 1, wherein the wall of the chamber has a thickness that is less than the predetermined length of the passageway.

25. The plasma processing system of claim 1, further comprising a fluid chamber surrounding the passageway.

26. The plasma processing system of claim 25, further comprising a fluid inlet in communication with the fluid chamber and a fluid outlet in communication with the fluid chamber, wherein a fluid having a certain temperature can be supplied to the fluid chamber through the fluid inlet and can be removed from the fluid chamber through the fluid outlet.

27. The plasma processing system of claim 25, further comprising a temperature controlled system associated with the fluid chamber and being capable of controlling a temperature of a fluid within the fluid chamber.

28. The plasma processing system of claim 27, wherein the temperature controlled system is configured to heat the fluid within the fluid chamber.

29. The plasma processing system of claim 27, wherein the temperature controlled system is configured to cool the fluid within the fluid chamber.

30. The plasma processing system of claim 1 , wherein the passageway has a variable diameter such that the predetermined diameter increases or decreases along the length of the passageway.

31. A method for operating a diagnostic system in conjunction with a plasma processing system having a processing chamber containing a plasma processing region in which a plasma can be generated during a plasma process, the diagnostic system including a diagnostic sensor and being coupled to the plasma processing region, the method comprising: providing a passageway formed between the plasma processing chamber and the diagnostic sensor, the passageway having a length to diameter ratio, provided by dividing a predetermined length of the passageway by a predetermined diameter of the passageway, of at least 4; substantially reducing contamination of the diagnostic sensor; and detecting a condition of the plasma process and/or a substrate in the processing chamber with the diagnostic sensor.

32. The method of claim 31 , further comprising restricting the passageway to a predetermined length and a predetermined diameter with a restrictor element.

33. The method of claim 31 , further comprising tapering the passageway so that the predetermined diameter increases or decreases along the passageway.

34. The method of claim 31 , wherein the substantially reducing includes providing fluid of a certain temperature substantially surrounding the passageway.

35. The method of claim 34, wherein the substantially reducing includes heating fluid substantially surrounding the passageway to a certain temperature.

36. The method of claim 34, wherein the substantially reducing includes cooling fluid substantially surrounding the passageway to a certain temperature.

37. The method of claim 31 , wherein the substantially reducing includes producing an electric field at least in the passageway or a vicinity thereof adjacent to the plasma processing chamber.

38. The method of claim 31, wherein the substantially reducing includes producing a magnetic field at least in the passageway or a vicinity thereof adjacent to the plasma processing chamber.

39. The method of claim 31 , wherein the substantially reducing includes: producing an electric field at least in the passageway or a vicinity thereof adjacent to the plasma processing chamber; and producing a magnetic field at least in the passageway or a vicinity thereof adjacent to the plasma processing chamber.

40. The method of claim 31 , wherein the substantially reducing includes: providing fluid of a certain temperature substantially around the passageway; and producing a magnetic field at least in the passageway or a vicinity thereof adjacent to the plasma processing chamber.

41. The method of claim 40, wherein the providing fluid of a certain temperature includes heating fluid substantially surrounding the passageway to the certain temperature.

42. The method of claim 40, wherein the providing fluid of a certain temperature includes cooling fluid substantially surrounding the passageway to the certain temperature.

43. The method of claim 31 , wherein the substantially reducing includes: providing fluid of a certain temperature substantially around the passageway; and producing an electric field at least in the passageway or a vicinity thereof adjacent to the plasma processing chamber.

44. The method of claim 43, wherein the providing fluid of a certain temperature includes heating fluid substantially surrounding the passageway to the certain temperature.

45. The method of claim 43, wherein the providing fluid of a certain temperature includes cooling fluid substantially surrounding the passageway to the certain temperature.

46. The method of claim 31, wherein the substantially reducing includes: providing fluid of a certain temperature substantially around the passageway; producing an electric field at least in the passageway or a vicinity thereof adjacent to the plasma processing chamber; and producing a magnetic field at least in the passageway or a vicinity thereof adjacent to the plasma processing chamber.

47. The method of claim 46, wherein the providing fluid of a certain temperature includes heating fluid substantially surrounding the passageway to the certain temperature.

48. The method of claim 46, wherein the providing fluid of a certain temperature includes cooling fluid substantially surrounding the passageway to the certain temperature.

49. A plasma processing system comprising: a chamber having an opening of a selected diameter and containing a plasma processing region; a chuck, constructed and arranged to support a substrate within the chamber in the processing region; a plasma generator in communication with the chamber, the plasma generator being constructed and arranged to generate a plasma during a plasma process in the plasma processing region; a diagnostic system having a diagnostic sensor in communication with the chamber; a passageway formed between the plasma processing region and the diagnostic sensor; and an electric field generator configured to produce an electric field at least in the passageway or a vicinity thereof adjacent to the plasma processing chamber such that contamination of the diagnostic sensor is reduced.

50. The plasma processing system of claim 49, wherein the electric field generator comprises an electrode assembly having at least one electrode.

51. The plasma processing system of claim 50, further comprising an insulator substantially surrounding the electric field generator.

52. The plasma processing system of claim 51 , further comprising a power supply coupled to the electric field generator to supply power to the electric field generator.

53. The plasma processing system of claim 52, wherein the power is DC or RF biased power.

54. A plasma processing system comprising: a chamber having an opening of a selected diameter and containing a plasma processing region; a chuck, constructed and arranged to support a substrate within the chamber in the processing region; a plasma generator in communication with the chamber, the plasma generator being constructed and arranged to generate a plasma during a plasma process in the plasma processing region; a diagnostic system having a diagnostic sensor in communication with the chamber; a passageway formed between the plasma processing region and the diagnostic sensor; and a magnetic field generator configured to produce a magnetic field at least in the passageway or a vicinity thereof adjacent to the plasma processing chamber such that contamination of the diagnostic sensor is reduced.

55. The plasma processing system of claim 54, further comprising a magnetic field leakage reducing member substantially surrounding the magnetic field generator.

56. The plasma processing system of claim 54, wherein the magnetic field generator comprises a plurality of magnets.

57. The plasma processing system of claim 56, wherein the plurality of magnets is positioned around the passageway such that each magnet of the plurality of magnets has a polarization direction separated from a polarization direction of an adjacent magnet by twice the separation angle between the magnets.

58. The plasma processing system of claim 56, wherein the plurality of magnets is positioned around the passageway such that each magnet of the plurality of magnets has a polarization direction directed in the same radial direction.

59. The plasma processing system of claim 56, wherein the plurality of magnets is positioned around the passageway such that alternate magnets of the plurality of magnets have a polarization direction directed in opposite radial directions.

60. The plasma processing system of claim 55, wherein the magnetic field generator comprises at least one current-carrying coil.

61. A plasma processing system comprising: a chamber having an opening of a selected diameter and containing a plasma processing region; a chuck, constructed and arranged to support a substrate within the chamber in the processing region; a plasma generator in communication with the chamber, the plasma generator being constructed and arranged to generate a plasma during a plasma process in the plasma processing region; a diagnostic system having a diagnostic sensor in communication with the chamber; a passageway formed between the plasma processing region and the diagnostic sensor; and a temperature controlled system including a fluid chamber surrounding the passageway, the temperature controlled system being capable of controlling a temperature of a fluid within the fluid chamber.

62. The plasma processing system of claim 61 , wherein the temperature controlled system includes a fluid inlet in communication with the fluid chamber and a fluid outlet in communication with the fluid chamber, wherein the fluid having a certain temperature can be supplied to the fluid chamber through the fluid inlet and can be removed from the fluid chamber through the fluid outlet.

63. The plasma processing system of claim 61 , wherein the temperature controlled system is configured to heat the fluid within the fluid chamber to the certain temperature.

64. The plasma processing system of claim 61 , wherein the temperature controlled system is configured to cool the fluid within the fluid chamber to the certain temperature.

65. A method for operating a diagnostic system in conjunction with a plasma processing system having a processing chamber containing a plasma processing region in which a plasma can be generated during a plasma process, the diagnostic system including a diagnostic sensor and being coupled to the plasma processing region, the method comprising: producing an electric field at least in a passageway formed between the plasma processing chamber and the diagnostic sensor or a vicinity thereof adjacent to the plasma processing chamber to substantially reduce contamination of the diagnostic sensor; and detecting a condition of the plasma process and/or a substrate in the processing chamber with the diagnostic sensor.

66. A method for operating a diagnostic system in conjunction with a plasma processing system having a processing chamber containing a plasma processing region in which a plasma can be generated during a plasma process, the diagnostic system including a diagnostic sensor and being coupled to the plasma processing region, the method comprising: producing a magnetic field at least in a passageway formed between the plasma processing chamber and the diagnostic sensor or a vicinity thereof adjacent to the plasma processing chamber to substantially reduce contamination of the diagnostic sensor; and detecting a condition of the plasma process and/or a substrate in the processing chamber with the diagnostic sensor.

67. A method for operating a diagnostic system in conjunction with a plasma processing system having a processing chamber containing a plasma processing region in which a plasma can be generated during a plasma process, the diagnostic system including a diagnostic sensor and being coupled to the plasma processing region, the method comprising: controlling a temperature of a fluid within a fluid chamber surrounding a passageway formed between the plasma processing chamber and the diagnostic sensor to substantially reduce contamination of the diagnostic sensor; and detecting a condition of the plasma process and/or a substrate in the processing chamber with the diagnostic sensor.

68. The plasma processing system of claim 3, wherein at least one of the restrictor element and a mounting portion substantially surrounding the passageway are made from a metal, a dielectric material and a semiconductor material.

69. The plasma processing system of claim 49, wherein the diagnostic system includes a restrictor element positioned in the passageway.

70. The plasma processing system of claim 69, wherein at least one of the restrictor element and a mounting portion substantially surrounding the passageway are made from a metal, a dielectric material and a semiconductor material.

71. The plasma processing system of claim 54, wherein the diagnostic system includes a restrictor element positioned in the passageway.

72. The plasma processing system of claim 71, wherein at least one of the restrictor element and a mounting portion substantially surrounding the passageway are made from a metal, a dielectric material and a semiconductor material.

73. The plasma processing system of claim 61, wherein the diagnostic system includes a restrictor element positioned in the passageway.

74. The plasma processing system of claim 63, wherein at least one of the restrictor element and a mounting portion substantially surrounding the passageway are made from a metal, a dielectric material and a semiconductor material.