Abstract: A method and system are presented for monitoring the optical emissions associated with a plasma used in integrated circuit fabrication. The optical emissions may be processed by an optical spectrometer to obtain a spectrum. The spectrum may be analyzed to determine the presence of particular disassociated species which are indicative of the presence of a suitable plasma and which may be desired for a deposition, etching, or cleaning process.

Abstract: In an ingredient analysis method and an ingredient analysis apparatus in accordance with the present invention, high-frequency power is supplied from a power source 4 while helium gas is supplied to an atmospheric pressure plasma source 2 disposed near a substance to be analyzed, whereby plasma 5 is generated, and the substance to be analyzed is exposed to the plasma 5 and emits light. The light is guided to a filter 7 and a photodiode 8 via an optical fiber 6 and subjected to photoelectrical conversion. The signal obtained by the photoelectrical conversion is sent to a controller 9. The controller 9 judges whether a specific element is present or not in the substance to be analyzed.

Abstract: The present invention provides an inductively coupled, magnetically enhanced ion beam source, suitable to be used in conjunction with probe-forming optics to produce an ion beam without kinetic energy oscillations induced by the source.

Abstract: Aspects of the present invention provide novel methods and devices for sampling gas, exciting the sampled gas to emit radiation and detecting in real time from the emitted radiation a plurality of wave bands of an emission spectrum. Energy used to excite the sampled gas may be adjusted based on the detected wave bands. A process may be controlled in real time based on the detected wave bands. Novel interfaces may be used to display portions of the detected wave bands. A known flow of a reference gas may be included in the flow of sampled gases and an unknown flow of an unknown flow gas determined.

Abstract: A microplasma emission spectrometer is described that includes a chamber for confining a sample volume of gas. A microplasma source that includes a resonant antenna structure generates a microplasma in the chamber from the sample volume of gas. A RF power supply provides power to the resonant antenna structure that generates the microplasma from the sample volume of gas. A spectrally sensitive detector is optically coupled to the microplasma. The entrance of the spectrally sensitive detector has dimensions and is positioned so that emissions from at least one-tenth of a total volume of the microplasma are transmitted through the entrance of the spectrally sensitive detector.

Abstract: A sensing device for sensing a condition of a plasma processing system component. The sensing device includes a main body configured to contain a material, an emitter contained in the main body and configured to emit light when exposed to a plasma, and a mating feature connected to the main body and configured to be mated with a receiving feature of an object in the plasma processing system such that the emitter material is exposed to a processing environment of the plasma processing system. When the emitter material is exposed to a plasma, the light emitted from the emitter can be monitored to determine at least one of material accumulation on the system component and erosion of the system component.

Abstract: In a method of spectroscopically analyzing a sample, a plasma is generated. A magnetic field is generated by a magnetic dipole wherein the plasma is confined within the magnetic field. Sample atoms are introduced into the plasma wherein energized atoms of the sample are confined. The spectral composition or mass-to-charge ratio of the energized sample atoms is analyzed. In a spectroscopic system a magnetic dipole has an associated magnetic field. A plasma is confined within the magnetic field and a sample of energized atoms introduced into the plasma. A spectrometer analyzes the energized atoms for the mass-to-charge ratio or for their spectral composition.

Abstract: The present invention relates to monitoring chemicals in a process chamber using a spectrometer having a plasma generator, based on patterns over time of chemical consumption. The relevant patterns may include a change in consumption, reaching a consumption plateau, absence of consumption, or presence of consumption. In some embodiments, advancing to a next step in forming structures on the workpiece depends on the pattern of consumption meeting a process criteria. In other embodiments, a processing time standard is established, based on analysis of the relevant patterns. Yet other embodiments relate to controlling work on a workpiece, based on analysis of the relevant patterns. The invention may be either a process or a device including logic and resources to carry out a process.

Abstract: A method and system are provided for monitoring erosion of system components in a plasma processing system. The system components contain a gas emitter that can release a sensor gas into a plasma process environment. The sensor gas can produce characteristic fluorescent light emission when exposed to a plasma. The method can evaluate erosion of system components in a plasma, by monitoring fluorescent light emission and a mass signal from the sensor gas. Consumable system components that can be monitored using the method include rings, shields, electrodes, baffles, and liners.

Abstract: Broadly speaking, an invention is provided for monitoring a plasma optical emission. More specifically, the present invention provides a method for monitoring the plasma optical emission through a variable aperture to detect an endpoint of a plasma etching process without interferences that could lead to false endpoint calls. The method includes collecting optical emission data from a plasma through an aperture defined by moveable members. The moveable members are capable of varying a configuration of the aperture. The method also includes holding the moveable members at a particular time to cause the aperture to maintain a fixed configuration. The method further includes detecting a specific perturbation in the plasma optical emission while holding the moveable members.

Abstract: Provided is a novel system for conducting elemental measurements using cavity ring-down spectroscopy (CRDS). The present invention provides sensitivity thousands of times improved over conventional devices and does so with the advantages of low power, low plasma flow rate, and the ability being sustained with various gases.

Abstract: A plasma source for a spectrometer includes a plasma torch (10) located within a waveguide or resonant cavity (40) for both the electric and the magnetic field components of a microwave electromagnetic field to excite a plasma (54). This produces a plasma (54) having a generally elliptical cross section into which sample is relatively easily injected but which still provides good thermal coupling between the plasma and the sample. The invention gives significantly improved limits of detection compared to prior art microwave induced plasma systems. The torch is preferably axially aligned with the direction of the magnetic field component and may be located within a resonant iris (32) within the waveguide or cavity (40).

Abstract: Aspects of the present invention provide novel methods and devices for sampling gas, exciting the sampled gas to emit radiation and detecting in real time from the emitted radiation a plurality of wave bands of an emission spectrum. Energy used to excite the sampled gas may be adjusted based on the detected wave bands. A process may be controlled in real time based on the detected wave bands. Novel interfaces may be used to display portions of the detected wave bands. A known flow of a reference gas may be included in the flow of sampled gases and an unknown flow of an unknown flow gas determined.

Abstract: A torch for producing an inductively coupled or microwave induced plasma for use in spectrochemical analysis. The torch includes a central tube (25) for conveying a flow of a gas carrying sample aerosol to a plasma (17) produced in the torch. The tube (25) has an inlet (31) and an outlet (39) of smaller size than the inlet and is shaped to deliver a substantially laminar flow of the gas at the outlet (39). The tube (25) is tapered along at least a substantial portion of its length such that its cross-section area gradually and smoothly reduces towards its outlet (39) along at least a substantial portion of its length. It has been found that such a tapered tube is resistant to obstruction by salts deposited from samples containing high levels of dissolved solids.

Abstract: An organometallic compound vaporizing and feeding system includes a carrier gas feed passageway connecting a carrier gas source to a container containing an organometallic compound MO and having a carrier gas mass flow controller, an MO gas passageway connecting the container to an in-line monitor for transporting the MO gas, a sample gas passageway connecting the in-line monitor to a sample inlet of an ICP spectrometer, a standard gas passageway connecting a gas cylinder filled with a calibration standard gas to the sample gas passageway and having a standard gas mass flow controller, and a diluent gas passageway connected to the standard gas passageway for passing a diluent gas for adjusting the concentration of the standard gas and having a diluent gas mass flow controller.

Abstract: A problem is to provide a microspray column capable of increasing the ionization efficiency, and a high sensitive mass spectrometer and a mass spectrometric method using such a microspray column. For solving this problem, we provide a column for introducing a sample in an ionization source of a mass spectrometer (ESI/MS) being designed to ionize a sample molecule with electrospray and introduce it into an analyzer, has structural features of: (1) 0.5 ?m or less in an inner diameter of a tip opening of the column; (2) 0.5 ?m or more and 5 ?m or less in a particle size of a column filler; and (3) fritless, a microspray column having the above (1) to (3), a mass spectrometer having such a microspray column in an ionization source, and a mass spectrometric method capable of performing a nonoflow electrospray with the microspray column.

Abstract: A method and apparatus for generating membrane targets for a laser induced plasma is disclosed herein. Membranes are advantageous targets for laser induced plasma because they are very thin and can be readily illuminated by high-power coherent light, such as a laser, and converted into plasma. Membranes are also advantageous because illumination of the membrane with coherent light produces less debris and splashing than illumination of a thicker, solid target. Spherical membranes possess additional advantages in that they can be readily illuminated from variety of directions and because they can be easily placed (i.e. blown) into a target region for illumination by coherent light. Membranes are also advantageous because they can be formed from a liquid or molten phase of the target material. According to another embodiment, membranes can be formed from a solution in which the target materials are solvated.

Abstract: A non-radioactive atmospheric pressure device for ionization of analytes comprises an atmospheric pressure chamber having an inlet for carrier gas, a first electrode at one end, and a counter-electrode at the other end of the chamber for creating an electrical discharge in the carrier gas thus creating metastable neutral excited-state species. Optionally, a grid is provided to generate electrons or ions by contact with the excited-state species. The carrier gas containing the excited-state species or the electrons generated therefrom is directed at an analyte at atmospheric pressure near ground potential to form analyte ions.

Abstract: A method and system are presented for monitoring the optical emissions associated with a plasma used in integrated circuit fabrication. The optical emissions are processed by an optical spectrometer to obtain a spectrum. The spectrum is analyzed to determine the presence of particular disassociated species which are indicative of the presence of a suitable plasma and which are desired for a deposition, etching, or cleaning process.

Abstract: A method for monitoring and/or controlling the positioning and/or condition of a plasma in a plasma spectrometer, which comprises: acquiring image data of the plasma through a video-camera (7), and a) displaying on a display device (10) a plasma image from the acquired image data; and/or b) storing the image data in a computer unit (9). Application to inductively coupled high frequency plasma optical emission and mass spectrometers.

Abstract: A method and system are provided for monitoring erosion of system components in a plasma processing system. The system components contain emitters that are capable of producing characteristic fluorescent light emission when exposed to a plasma. The method utilizes optical emission to monitor fluorescent light emission from the emitters for determining system component status. The method can evaluate erosion of system components in a plasma, by monitoring fluorescent light emission from the emitters. Consumable system components that can be monitored using the method include rings, shields, electrodes, baffles, and liners.

Abstract: An apparatus for determining one or more elements or compounds in a laboratory sample, and for simultaneously performing both vapor generation and nebulization in one device, is disclosed. The apparatus comprises an enclosed cyclonic spray chamber with two integrally affixed cylindrical ports, one for introducing a nebulizer into the chamber and the other for facilitating volatilization of analytes within the chamber. In addition, two conical tubes are integrally affixed to the chamber and oriented opposite each other, with one tube serving as the means for introducing a sample into the spray chamber, and the other tube serving as the means for introducing reductant/reactant into the spray chamber. This invention allows a sample that has been introduced into the spray chamber to be subjected to nebulization or vapor generation, or to both processes.

Abstract: This invention concerns a plasma source emission spectrometer to measure a sample comprising an excitation source (2) having a central axis (3) and producing a plasma, an extraction enclosure (4) receiving a beam composed of ions, atoms and electrons (5) derived from the plasma and comprising an optical lens (10) collecting luminous radiations emitted by the ion beam (5). According to the invention, the lens (10) is not exposed directly to the plasma. The invention also concerns a sighting device (100) comprising a metallic structure (13), substantially cylindrical having a first (15) and second (16) faces ranging respectively in a first (17) and second (18) planes. The first face (15) comprises an input aperture (20) for a beam (5) to be analysed and the second face (16) comprises an output aperture (28) for said beam (5). The first plane (17) forms an angle ? with the normal of the second plane (18).

Abstract: The present invention relates to an apparatus and method for forming a plasma in the exhaust line of a primary process reactor. The plasma is generated in an inductive source (5) to examine the chemical concentrations of the waste or exhaust gas in vacuum lines that are below atmospheric pressure. The optical radiation emitted by the plasma is analyzed by an optical spectrometer (9) and the resulting information is used to diagnose, monitor, or control operating states in the main vacuum vessel.

Abstract: A sample introduction system for ICPMS and ICPAES comprising a nebulizer which sprays liquid samples into a heated cyclonic spray chamber which has a common exit port for both liquid waste and sample aerosol which is coupled to a desolvation system comprised of condenser and revaporization loops that alternately condense solvent vapor both on the inner walls of the loop and in the aerosol stream, then revaporize the portion of solvent condensed in the aerosol stream for subsequent condensation in the next loop. The exit port of the system is capable of being directly or remotely coupled to the ICP injector tube.

Abstract: A system atomizes liquids into a gaseous medium for formation and injection of a sample into an analytical apparatus, such as a plasma spectrometer. The system employs a high efficiency nebulizer that generates a fine aerosol through use of a nozzle having improved surface wetness characteristics, preferably in combination with a deflecting surface. A desolvator is employed to remove excess solvent from the atomized sample prior to injection into the spectrometer to avoid temperature reduction or extinguishment of the plasma by the sample.

Abstract: A glow discharge spectroscopy (GDS) source operates at atmospheric pressure. One of the discharge electrodes of the device is formed by an electrolytic solution 27 containing the analyte specimen. The passage of electrical current (either electrons or positive ions) across the solution/gas phase interface causes local heating and the volatilization of the analyte species. Collisions in the discharge region immediately above the surface of the solution results in optical emission and ionization that are characteristic of the analyte elements. As such, these analyte elements can be identified and quantified by optical emission spectroscopy (OES) or mass spectrometry (MS). The device uses the analyte solution as either the cathode or anode. Operating parameters depend on the electrolyte concentration (i.e. solution conductivity) and the gap 35 between the solution surface and the counter electrode.

Abstract: A method and system are provided for monitoring material buildup on system components in a plasma processing system. The system components contain emitters that are capable of producing characteristic fluorescent light emission when exposed to a plasma. The method utilizes optical emission to monitor fluorescent light emission from the emitters for determining system component status. The method can evaluate material buildup on system components in a plasma, by monitoring fluorescent light emission from the emitters. Consumable system components that can be monitored using the method include rings, shields, electrodes, baffles, and liners.

Abstract: The invention is directed to an arrangement for stabilizing the radiation emission of a plasma, particularly for generating extreme ultraviolet (EUV) radiation.

Abstract: A torch for producing an inductively coupled or microwave induced plasma for use in spectrochemical analysis. The torch includes a central tube (25) for conveying a flow of a gas carrying sample aerosol to a plasma (17) produced in the torch. The tube (25) has an inlet (31) and an outlet (39) of smaller size than the inlet and is shaped to deliver a substantially laminar flow of the gas at the outlet (39). The tube (25) is tapered along at least a substantial portion of its length such that its cross-sectional area gradually and smoothly reduces towards its outlet (39) along at least a substantial portion of its length. It has been found that such a tapered tube is resistant to obstruction by salts deposited from samples containg high levels of dissolved solids.

Abstract: Afterglow spectroscopy allows observing light emission of gaseous species in absence of direct plasma light. This absence avoids the creation of a background spectrum obscuring weak emission from trace species. The invention describes a flowing afterglow version monitoring in-situ the cleanup of vacuum tools during pump/purge cycles. The invention also describes an intermittent afterglow version suitable for trace gas analysis at atmospheric pressure.

Abstract: In a method of spectroscopically analyzing a sample, a plasma is generated. A magnetic field is generated by a magnetic dipole wherein the plasma is confined within the magnetic field. Sample atoms are introduced into the plasma wherein energized atoms of the sample are confined. The spectral composition or mass-to-charge ratio of the energized sample atoms is analyzed. In a spectroscopic system a magnetic dipole has an associated magnetic field. A plasma is confined within the magnetic field and a sample of energized atoms introduced into the plasma. A spectrometer analyzes the energized atoms for the mass-to-charge ratio or for their spectral composition.

Abstract: Process and apparatus for real-time determination of a solid sample composition as a function of the depth within the sample. The process comprises: forming a glow discharge (16) of atoms sputtered from an exposed area (17) of the sample (13) and analysing the glow discharge by optical emission spectroscopy; measuring the distance between said exposed area (17) and a fixed reference surface (12a) and determining from the measured distance the depth of the exposed area within the sample; and correlating the determined depth of the exposed area with the glow discharge analysis. Application to material analysis.

Abstract: Provided is a novel system for conducting elemental measurements using cavity ring-down spectroscopy (CRDS). The present invention provides sensitivity thousands of times improved over conventional devices and does so with the advantages of low power, low plasma flow rate, and the ability being sustained with various gases.

Abstract: A gas plasma emission source includes a solid state signal power source coupled to a resonant cavity. In an alternative embodiment of the invention, an atomic emission detector includes a solid state signal power source coupled to a resonant cavity and a spectrographic detector to sense atomic emissions from a gas within the resonant cavity. In yet another embodiment of the invention, a method of sustaining a plasma includes passing a gas through a resonant cavity and exciting the resonant cavity with signal power from a solid state power source to sustain the plasma in the gas. In another embodiment of the invention, a method of using a solid state power source includes passing a gas through a resonant cavity and coupling sufficient signal power from an output of the solid state power source to sustain a plasma in the gas where the sufficient power is less than 300 watts.

Abstract: A method and system are provided for monitoring material buildup on system components in a plasma processing system. The system components contain emitters that are capable of producing characteristic fluorescent light emission when exposed to a plasma. The method utilizes optical emission to monitor fluorescent light emission from the emitters for determining system component status. The method can evaluate material buildup on system components in a plasma, by monitoring fluorescent light emission from the emitters. Consumable system components that can be monitored using the method include rings, shields, electrodes, baffles, and liners.

Abstract: A method and system are provided for monitoring erosion of system components in a plasma processing system. The system components contain emitters that are capable of producing characteristic fluorescent light emission when exposed to a plasma. The method utilizes optical emission to monitor fluorescent light emission from the emitters for determining system component status. The method can evaluate erosion of system components in a plasma, by monitoring fluorescent light emission from the emitters. Consumable system components that can be monitored using the method include rings, shields, electrodes, baffles, and liners.

Abstract: Aspects of the present invention provide novel methods and devices for sampling gas, exciting the sampled gas to emit radiation and detecting in real time from the emitted radiation a plurality of wave bands of an emission spectrum. Energy used to excite the sampled gas may be adjusted based on the detected wave bands. A process may be controlled in real time based on the detected wave bands. Novel interfaces may be used to display portions of the detected wave bands. A known flow of a reference gas may be included in the flow of sampled gases and an unknown flow of an unknown flow gas determined.

Abstract: A method and apparatus for analyzing a semiconductor surface obtains a sample from a localized section of a wafer. The sample is obtained by isolating a section of a wafer with a sampling apparatus, dispensing liquid onto the isolated section of the wafer, dissolving compounds of interest in the liquid, removing a portion of the liquid, and analyzing the liquid and dissolved compounds of interest. The liquid can be an etching solution, an organic solvent, or other suitable solvent. Samples and analyses can, thus, be obtained as a function of position on the wafer. Analyses as a function of depth can also be determined by sampling and analyzing an isolated portion of the wafer as a function of time.

Abstract: A dry processing apparatus includes a processing chamber provided with a measurement window having a reflection portion which totally reflects light on the side of an inner surface thereof and a transmission portion. When a layer is not deposited, measurement light is irradiated so that the light is totally reflected by the reflection portion. A deviation between the measurement light reflected by a surface of the deposited layer and the measurement light reflected by the reflection portion is measured to determine a thickness of the deposited layer. A quantity of light reflected by the surface of the deposited layer is compared with the light quantity in case where irregularities are not formed in the surface of the deposited layer to evaluate a state of irregularities of the surface. The thickness of the deposited layer and a state of the surface of the layer are monitored separately.

Abstract: A low-power, plasma source-based, portable molecular light emission generator/detector employing an atmospheric pressure pulsed-plasma for molecular fragmentation and excitation is described. The average power required for the operation of the plasma is between 0.02 W and 5 W. The features of the optical emission spectra obtained with the pulsed plasma source are significantly different from those obtained with direct current (dc) discharge higher power; for example, strong CH emission at 431.2 nm which is only weakly observed with dc plasma sources was observed, and the intense CN emission observed at 383-388 nm using dc plasma sources was weak in most cases. Strong CN emission was only observed using the present apparatus when compounds containing nitrogen, such as aniline were employed as samples. The present apparatus detects dimethylsulfoxide at 200 ppb using helium as the plasma gas by observing the emission band of the CH radical.

Abstract: The present invention provides a method and an apparatus for analyzing nitrogen in a gas, in which the concentration of nitrogen can be continuously measured with good sensitivity without wasting a sample gas. At least one wavelength for measuring a concentration of nitrogen according to the intensity of a light generated by discharge, is selected from a group consisting of 215±2 nm, 226±2 nm, 238±2 nm, 242±2 nm, 246±1 nm, 256±2 nm, 260±2 nm, 266±2 nm, 271±1 nm, 276±4 nm, 285±2 nm, 294±1 nm, and 300±2 nm.

Abstract: An ICP analyzer has a nebulizer for nebulizing a sample fluid for the purpose of analyzing microscopic impurities within the sample fluid, a plasma torch for introducing nebulized spray into a plasma, and a spray chamber disposed between the nebulizer and the plasma torch for separating spray comprised of microscopic particles from the nebulized spray prior to introduction thereof into the plasma torch. A heating section is provided at a central portion of the spray chamber and a cooling section is provided at a peripheral section of the spray chamber, and the spray is passed between the heating section and the cooling section to improve the efficiency sample introduction into the plasma to enable highly sensitive analysis by suppressing the proportion of a solvent component that reaches the plasma torch.

Abstract: A glow discharge spectroscopy (GDS) source operates at atmospheric pressure. One of the discharge electrodes of the device is formed by an electrolytic solution 27 containing the analyte specimen. The passage of electrical current (either electrons or positive ions) across the solution/gas phase interface causes local heating and the volatilization of the analyte species. Collisions in the discharge region immediately above the surface of the solution results in optical emission and ionization that are characteristic of the analyte elements. As such, these analyte elements can be identified and quantified by optical emission spectroscopy (OES) or mass spectrometry (MS). The device uses the analyte solution as either the cathode or anode. Operating parameters depend on the electrolyte concentration (i.e. solution conductivity) and the gap 35 between the solution surface and the counter electrode.

Abstract: The disclosed invention relates to a calibration method, system and apparatus for a multimetals continuous emissions monitor system (hereinafter “multimetals CEMS”). More specifically, this invention relates to a calibration scheme for continuous monitoring of mercury emissions from stationary sources by plasma emission spectrometry. A source of mercury vapor, preferably a mercury permeation tube, entrains mercury vapor into a constant flow of carrier air. The carrier air mixes with a constant flow of diluent air in an aerosol mixer. The mixer is operably coupled to the analyzer. A gaseous mixture having a calibration mercury concentration flows from the mixer into the analyzer at a constant rate. A graph having coordinates of analyzer signal intensity and mercury concentration is used to plot the calibration scheme. A first signal intensity generated by the analyzer in response to the calibration mercury concentration is used for the first plot on the graph.

Abstract: Glow discharge apparatus having liquid electrodes includes a substrate with a top surface on which cathode and anode electrodes are formed. The cathode electrode may be formed with a cathode terminal port formed to hold a liquid which is spaced from the anode electrode by an inter-electrode surface of the substrate. Electrical conductors are connected to the anode and cathode electrodes to allow a voltage to be applied between them, resulting in a glow discharge in the gap over the inter-electrode surface that causes sputtering of the liquid in the cathode terminal port into the glow discharge. Excitation by the glow discharge of the sputtered or evaporated liquid allows spectroscopic analysis of the constituents of the liquid in the electrode.

Abstract: Using a nebulizer gas, sub micron and micron size particulates can be generated from a solution containing salts covering a broad range of elements. The fractional concentration of elements can be determined by bubbling the aerosol through aqueous acid and analyzing the aqueous acid for metals. The nebulizer can be coupled to an ICP (Inductively Coupled Plasma) torch and the ICPMS (Inductively Coupled Plasma Mass Spectrometer) or ICPOES (Inductively Coupled Plasma Optical Emission Spectrometer) response to different elements can be determined. This provides the response factor of the ICPMS or ICPOES for different elements.

Abstract: This invention provides a glow discharge emission spectroscopic analysis apparatus which is capable of making a desired chemical analysis with excellent reproducibility. A glow discharge emission spectroscopic analysis apparatus of this invention is constituted so that the sample is held by a first electrical conductor provided on one side of a glow discharge tube and a second electrical conductor is movable by a cylinder rod to secure the sample in contact with the first electrical conductor. The electrical conductors can be electrically connected with each other. when the sample is secured, and a negative electric potential is applied to the electrical conductors.

Abstract: An apparatus (10) and method for detecting and analyzing the spectra of light emitted by a plasma (36) in a plasma duct (16) having a plurality of windows (40) formed therein. In one embodiment, the apparatus includes an optical system (50) arranged adjacent each window that directs light emanating from the plasma and passing through each window to two or more optical filters (F1, F2) having different bandwidths so that different portions of the light spectra (S1, S2) can be measured. The filter light is incident respective two or more detectors (D1, D2), which produce an electrical signal representative of the intensity of light incident thereon, and thus is a measure of the content of a select band of the light spectrum. Performing this measurement for different regions (R) of the plasma yields different spectra and thus provides information about the plasma properties, thereby allowing for adjustment of those properties.

Abstract: This invention concerns a plasma source emission spectrometer to measure a sample comprising an excitation source (2) having a central axis (3) and producing a plasma, an extraction enclosure (4) receiving a beam composed of ions, atoms and electrons (5) derived from the plasma and comprising an optical lens (10) collecting luminous radiations emitted by the ion beam (5). According to the invention, the lens (10) is not exposed directly to the plasma. The invention also concerns a sighting device (100) comprising a metallic structure (13), substantially cylindrical having a first (15) and second (16) faces ranging respectively in a first (17) and second (18) planes. The first face (15) comprises an input aperture (20) for a beam (5) to be analysed and the second face (16) comprises an output aperture (28) for said beam (5). The first plane (17) forms an angle &agr; with the normal of the second plane (18).