Plasma processing system and method of measuring quantities of species in the same

Abstract

A plasma processing system includes: a plasma chamber configured to contain plasma; a shutter chamber fluidly coupled to the plasma chamber via a first orifice; a mass spectrometer fluidly coupled to the shutter chamber; and a shutter disposed in the shutter chamber between the first orifice and the mass spectrometer and positioned in the path of a particle beam. The first orifice is configured to use a pressure difference between the shutter chamber and the plasma chamber to generate the particle beam from the plasma. The mass spectrometer includes an ionizer configured to ionize species of the particle beam by sweeping through an electron energy range in a complex energy phase. The shutter is configured to open and close during each of the complex energy phases.

Description

Technical Field

[0001] The present invention is generally related to measuring the number of species in a processing chamber, and in a particular embodiment, the present invention relates to a system and method for quantifying the species present in a processing chamber by means of electron energy generated by a sweep ionizer. Prior Technology

[0002] For process and equipment development, diagnostic information is crucial during semiconductor manufacturing processes such as plasma processes. During semiconductor manufacturing, numerous species can be generated within the processing chamber. For example, during plasma processes, a wide variety of ions, neutral radicals, and metastable species are generated from the potential cracking patterns of the gas within the plasma chamber. Accurate quantification of these numerous species is beneficial for determining optimal processing parameters and improving equipment design.

[0003] To quantify species within a processing chamber, a mass spectrometer can be incorporated into a semiconductor processing system (e.g., a plasma processing system). In some cases, the mass spectrometer may be attached to the plasma chamber, for example. However, in many applications, limitations exist due to the high cost and large footprint of accurate mass spectrometer equipment. Furthermore, the range of processes that can be measured may be limited, and data collection may be slow and complex. Therefore, processing systems incorporating low-cost, small-footprint mass spectrometers that automatically and accurately quantify and identify various substances within the processing chamber are desirable. Summary of the Invention

[0004] According to one embodiment of the present invention, a plasma processing system includes: a plasma chamber configured to contain plasma; a shutter chamber fluidly coupled to the plasma chamber via a first orifice; a mass spectrometer fluidly coupled to the shutter chamber; and a shutter disposed in the shutter chamber between the first orifice and the mass spectrometer and positioned in the path of a particle beam. The first orifice is configured to use a pressure difference between the shutter chamber and the plasma chamber to generate the particle beam from the plasma. The mass spectrometer includes an ionizer configured to ionize species of the particle beam by sweeping through an electron energy range in a complex energy phase. The shutter is configured to open and close during each of the complex energy phases.

[0005] According to another embodiment of the present invention, a method for measuring the number of species in a processing chamber includes the following steps: closing a shutter disposed between a processing chamber and a mass spectrometer to block a particle beam originating from the processing chamber. The mass spectrometer includes an ionizer. The method further includes setting the electron energy of the ionizer to an initial energy value, and sweeping the electron energy from the initial energy value to a final energy value by cyclically performing the following steps: collecting background quantization data when the shutter is closed, opening the shutter, collecting signal quantization data of the species in the particle beam when the shutter is open, closing the shutter, and setting the electron energy to a next value. The method also includes, after collecting signal quantization data at the electron energy set to the final energy value, using the signal quantization data and the background quantization data to determine the number of species in the processing chamber.

[0006] According to another embodiment of the present invention, a method for measuring the quantity of a species present in a processing chamber includes the following steps: sweeping the electron energy of an ionizer of a mass spectrometer during a complex energy phase starting at an initial energy value and ending at a final energy value; generating a data set by collecting a series of data points corresponding to a detection event of the species at each of the complex energy phases; and determining the quantity of the first variety of the species present in the processing chamber using a first interval of the data set starting at a critical ionization energy of a first variety of the species. The species includes a mass / charge ratio selected by the mass spectrometer, and the first variety also has the mass / charge ratio. Simple Explanation of the Diagram

[0007] To gain a more complete understanding of the invention and its advantages, reference is now made to the following description, which is taken in conjunction with the accompanying drawings, in which:

[0008] According to one embodiment of the present invention, FIG1 illustrates a schematic cross-sectional view of an exemplary processing system including a mass spectrometer, which is coupled to the processing chamber via a beam-forming phase;

[0009] According to one embodiment of the present invention, FIG2 illustrates a schematic cross-sectional view of an exemplary processing system including a mass spectrometer, which is coupled to the processing chamber via a beamforming stage, the beamforming stage including a shutter chamber and a quiescence chamber;

[0010] According to one embodiment of the present invention, FIG3 illustrates a schematic cross-sectional view of an exemplary processing system including a mass spectrometer, which is coupled to the processing chamber via a beamforming stage, the beamforming stage including a buffer chamber, an optical shutter chamber, and a stationary chamber;

[0011] According to one embodiment of the present invention, FIG4 illustrates a schematic cross-sectional view of another exemplary processing system including a mass spectrometer, which is coupled to the processing chamber via a beamforming stage, the beamforming stage including a buffer chamber, an optical shutter chamber, and a stationary chamber;

[0012] According to one embodiment of the present invention, FIG5 illustrates a schematic arrangement of an exemplary processing system including a mass spectrometer, which is coupled to the processing chamber via a beamforming stage, the beamforming stage including a buffer chamber, an optical shutter chamber, and a stationary chamber;

[0013] According to one embodiment of the present invention, FIG6 illustrates a flowchart of an exemplary method for collecting quantization data from a processing chamber using an optical shutter and electron energy sweeping;

[0014] According to one embodiment of the present invention, Figure 7 illustrates two graphs illustrating a demonstrative method for collecting quantitative data from a processing chamber to measure the number of species in the processing chamber by using an optical shutter and electron energy sweeping;

[0015] According to one embodiment of the present invention, Figure 8 illustrates an exemplary method for measuring the number of species present in a processing chamber using collected quantitative data; and

[0016] According to one embodiment of the present invention, Figure 9 illustrates an exemplary method for measuring the number of species present in a processing chamber using electron energy scanning.

[0017] Unless otherwise specified, the numbers and symbols corresponding to different figures refer to the corresponding parts. The figures are depicted to clearly illustrate the relevant concepts of the embodiments, but are not necessarily drawn to scale. The edges of features depicted in the figures do not necessarily indicate the limits of the range of that feature. Implementation

[0018] The following details the manufacture and use of various embodiments. However, it should be understood that the various embodiments described herein can be applied to a wide variety of specific situations. The specific embodiments discussed are merely illustrative of specific ways of manufacturing and using the various embodiments and should not be interpreted within a limited scope.

[0019] Conventional mass spectrometry processing systems are subject to various drawbacks and trade-offs when used for chemical diagnostics (e.g., density, species identification, quantification) during semiconductor and / or plasma processes. For example, conventional practices of connecting a mass spectrometer to a processing chamber may be prohibitively expensive and / or bulky. Furthermore, the process range used for measurements may be undesirably small. Density and species quantification / identification measurements may be quantitatively inaccurate, with many species potentially misidentified or not detected at all.

[0020] Furthermore, conventional data collection can be excessively slow or complex. Specialized engineers may be required to interpret and analyze the collected data, resulting in additional expenditure of human and time resources. To achieve a high signal-to-noise ratio, conventional mass spectrometers utilize ionizers with electron energies set at well above either the free or dissociation energy (e.g., 70 eV) to generate a binding detection signal from a specific mass of all possible species from all possible sources. Disadvantageously, it is impossible to separate and evaluate individual detection signals representing compositions from different species / sources.

[0021] In various embodiments, the processing system includes a processing chamber configured to accommodate various species. For example, the processing chamber may be a plasma chamber configured to contain plasma generated by one or more gaseous substances within the plasma chamber. The processing system also includes a mass spectrometer fluidly coupled to the processing chamber via a beam-forming stage. The beam-forming stage includes a vacuum chamber fluidly coupled to the processing chamber via an orifice configured to utilize the pressure difference between the vacuum chamber and the plasma chamber to generate a particle beam originating from the processing chamber.

[0022] The mass spectrometer includes an ionizer configured to ionize species in the particle beam by sweeping through an electron energy range in the complex energy stages. In one embodiment, the mass spectrometer is a residual gas analyzer (RGA) mass spectrometer. An optical shutter system is disposed in a vacuum chamber located between the aperture and the mass spectrometer and positioned in the path of the particle beam. The optical shutter system is configured to open and close during each of the complex energy stages. In one embodiment, the optical shutter system is configured to rotate by an electric motor mechanically coupled to the shutter.

[0023] In various embodiments, the beamforming stage includes a plurality of vacuum chambers, including vacuum chambers with shutters (which may be referred to herein as shutter chambers). For example, the beamforming stage may include tandem vacuum chambers, each fluidly coupled to a corresponding vacuum pump. Additional vacuum chambers in the beamforming stage may each be located between the processing chamber and the mass spectrometer and before or after the shutter chambers.

[0024] The systems and processes described herein can advantageously overcome various drawbacks of conventional systems and processes. For example, the embodiment processing system can advantageously facilitate the monitoring of process species, reaction products, process drift, and chamber conditions during semiconductor processes (e.g., plasma processes such as plasma etching and plasma deposition processes) and thermal processes.

[0025] The processing system described in this embodiment offers the following advantages: it has a smaller footprint than conventional processing systems using mass spectrometers. Furthermore, the processing system described in this embodiment is advantageously cheaper than conventional practices. The smaller footprint can also bring the additional advantage of reduced pumping volume requirements, further reducing footprint and cost.

[0026] Other potential advantages of the process described herein include increased data collection speed and reduced analytical complexity. For example, the processing system can be configured to automatically acquire quantified data and compensate for baseline and / or background effects. Accuracy can also be advantageously improved due to real-time background compensation, which mitigates the impact of transient effects such as process drift.

[0027] Furthermore, the process described in this embodiment can advantageously detect a wider range of species with improved accuracy. For example, the same species from different sources (e.g., ionized neutral particles from plasma, dissociated neutral particles from plasma, background species) can be distinguished from each other. In addition, metastable species (e.g., excited states of stable species) can also be detected and quantified.

[0028] The embodiments provided below illustrate various systems and methods for measuring the quantity of species in a processing chamber, and in certain embodiments, include systems and methods for sweeping electron energy generated by an ionizer. The following description is illustrative of the embodiments. Figure 1 illustrates an embodiment processing system including a mass spectrometer coupled to the processing chamber via a beamforming stage. Figures 2-4 illustrate three other embodiment processing systems. The schematic arrangement in Figure 5 illustrates another embodiment processing system. Figure 6 illustrates an embodiment method for collecting quantification data. Figures 7-9 illustrate three embodiment methods for measuring the quantity of species present in a processing chamber.

[0029] According to one embodiment of the present invention, FIG1 illustrates a schematic cross-sectional view of an exemplary processing system including a mass spectrometer, which is coupled to the processing chamber via a beamforming stage.

[0030] Referring to Figure 1, the processing system 100 includes a processing chamber 130, which is fluidly coupled to a mass spectrometer 140 via a beam-forming stage 110. The beam-forming stage 110 includes a vacuum chamber 112 and a shutter 120, which is located within the vacuum chamber 112 and along the path 124 of the particle beam originating from the processing chamber 130. The particle beam is generated using the pressure difference between the vacuum chamber 112 and the processing chamber 130 via an aperture 114. The aperture 114 facilitates fluid communication between the processing chamber 130 and the vacuum chamber 112. For example, particles (e.g., in the gas phase or plasma phase) can pass from the processing chamber 130 through the aperture 114 and enter the vacuum chamber 112 as a particle beam (e.g., a molecular beam containing ions, neutral particles, etc.).

[0031] Using the outward particle stream 128 at the discharge port 118, the pressure in the vacuum chamber 112 is maintained at a lower pressure than that in the processing chamber 130 (which may also be under vacuum). For example, the outward particle stream 128 may be generated by a vacuum pump coupled to the discharge port 118. The mass spectrometer 140 is fluidly coupled to the beam-forming stage 110 at interface 144. In one embodiment, the mass spectrometer 140 is directly coupled to the vacuum chamber 112 at interface 144. Alternatively, the beam-forming stage 110 may be included in an additional chamber before or after the vacuum chamber 112 and along the path of the particle beam.

[0032] When shutter 120 is in the closed position, it is configured to block the particle beam path 124. That is, when shutter 120 is closed, the particle beam is prevented from reaching the mass spectrometer 140. When shutter 120 is closed, particles from the beam can impact shutter 120 and be pumped out through the discharge port 118. In this way, when shutter 120 is in the closed position, the mass spectrometer 140 can measure background data. Conversely, when shutter 120 is in the open position, it is configured to allow the particle beam to reach the mass spectrometer 140 along path 125. Subsequently, when shutter 120 is open, the mass spectrometer 140 can measure signal data (which includes signals from both the particle beam and the background).

[0033] Processing chamber 130 can be any suitable processing chamber. For example, processing chamber 130 can be a semiconductor processing chamber. In various embodiments, processing chamber 130 is a plasma chamber, in some embodiments a plasma etching chamber, and in some embodiments a plasma deposition chamber. In some embodiments, processing chamber 130 can also be a thermal processing chamber. In one embodiment, processing system 100 is a plasma-enhanced atomic layer deposition (PE-ALD) system. In another embodiment, processing system 100 is a plasma-enhanced atomic layer etching (PE-ALE) system. In yet another embodiment, processing system 100 is a thermal processing system. In many cases, processing system 100 is a multi-purpose processing system capable of performing various processes.

[0034] For example, processing chamber 130 can be any suitable processing chamber in which semiconductor processing is performed. It is desirable to monitor chemical species within processing chamber 130 during various semiconductor processes. Therefore, in addition to or alternative to the specific examples described above, processing system 100 may include a photolithography module, a gas etching / cleaning / stripping module, and others. In some applications, processing chamber 130 may be generalized to other parts of the processing system (e.g., gas supply lines, vacuum lines (e.g., chemical analysis in downstream vacuum lines for collecting information about upstream processes), effluent lines), and other locations within which it is desirable to quantify gaseous chemicals to characterize a process.

[0035] Mass spectrometer 140 can be any suitable type of mass spectrometer, including an ionizer 146 (e.g., a filament). In one embodiment, mass spectrometer 140 is an RGA mass spectrometer. In some embodiments, the ionizer 146 of mass spectrometer 140 may extend through interface 144 (as shown). For example, ionizer 146 may be contained in a chamber fluidly coupled to mass spectrometer 140 along particle beam path 124 (e.g., the illustrated vacuum chamber 112). Alternatively, the ionizer may also be contained within mass spectrometer 140.

[0036] In addition to the ionizer, an RGA mass spectrometer may include a mass filter (e.g., an electromagnetic filter, such as a quadrupole filter), which allows only a narrow range of masses to pass through at a given time. Since the mass filter can operate electromagnetically, the ability of a particle to pass through it can also depend on its charge. For example, the mass filter of mass spectrometer 140 may only allow particles with substantially similar mass / charge ratios (m / z) to pass through and reach the detector.

[0037] Mass spectrometer 140 may require sufficiently low pressure to operate. For example, the pressure in mass spectrometer 140 may be less than about 7.5 × 10⁻⁶ Torr. In order to enable the mass spectrometer to operate and also to form a particle beam, beam forming stage 110 may advantageously facilitate an appropriate pressure difference between processing chamber 130 and mass spectrometer 140.

[0038] Various species can be detected by mass spectrometer 140. In various embodiments, neutral species originating from processing chamber 130 are detected by mass spectrometer 140. However, ions can also be detected by mass spectrometer 140.

[0039] According to one embodiment of the present invention, FIG2 illustrates a schematic cross-sectional view of an exemplary processing system including a mass spectrometer coupled to a processing chamber via a beamforming stage, which includes a shutter chamber and a stationary chamber. For example, the processing system of FIG2 may be a specific implementation of other processing systems described herein, such as the processing system of FIG1. ​​Elements as previously indicated may be as described.

[0040] Referring to Figure 2, the processing system 200 includes a processing chamber 230, which is fluidly coupled to the mass spectrometer 240 via a beamforming stage 210. It should be noted that, for brevity and clarity, a convention has been adopted here and below, wherein elements conforming to pattern "_10" can be related implementations of the beamforming stage in various embodiments. For example, unless otherwise stated, beamforming stage 210 can be similar to beamforming stage 110. A similar convention is adopted for other elements, which is clearly indicated by the use of similar terminology and in conjunction with the aforementioned three-digit numbering system.

[0041] The beam-forming stage 210 is fluidly coupled to the processing chamber 230 via a first orifice 214, which allows the particle beam to enter the shutter chamber 212 of the beam-forming stage 210. A shutter 220 is contained within the shutter chamber 212 and serves to block the particle beam's path 224 in a closed position and allow the particle beam to reach the interface 244 (and ionizer 246) of the mass spectrometer 240 along path 225 in an open position. In one embodiment, the shutter 220 is a double-sided shutter as illustrated. Double-sided shutters can advantageously facilitate rapid switching and reduce background interference. The shutter chamber 212 is emptied using a first outward particle stream 228 generated at the first discharge port 218.

[0042] The beam-forming stage 210 further includes a stationary chamber 213, which is fluidly coupled to the shutter chamber 212 via a second aperture 215. In various embodiments, the diameter of the second aperture 215 is larger than the diameter of the first aperture 214, and in one embodiment, it is approximately twice the size of the diameter of the first aperture 214. For example, the diameter of the first aperture 214 may be approximately 20 / 1000 inch (~0.5 mm), while the diameter of the second aperture 215 may be approximately 35 / 1000 inch (~0.9 mm).

[0043] The quiescent chamber 213 can be configured to reduce interruptions in measurements on the mass spectrometer 240 caused by the operation of the shutter 220. In various embodiments, the ionizer 246 of the mass spectrometer 240 extends through the interface 244 and, in one embodiment, is disposed within the quiescent chamber 213. The distance between the ionizer 246 and the second aperture 215 can be small. For example, a small distance between the ionizer 246 and the second aperture 215 can advantageously facilitate a narrow particle beam (e.g., reduce beam dispersion along path 225).

[0044] Alternatively, the quiescent chamber 213 can be used to further improve the signal-to-noise ratio in the mass spectrometer 240. The quiescent chamber 213 is emptied using a second outward particle stream 229 generated at the second discharge port 219. Individual emptying of the quiescent chamber 213 lowers the pressure within it compared to the pressure in the shutter chamber 212. Therefore, the signal-to-noise ratio can be advantageously improved in the mass spectrometer 240.

[0045] According to one embodiment of the present invention, FIG3 illustrates a schematic cross-sectional view of an exemplary processing system including a mass spectrometer coupled to a processing chamber via a beamforming stage, which includes a buffer chamber, an optical shutter chamber, and a stationary chamber. For example, the processing chamber of FIG3 may be a specific implementation of other processing systems described herein, such as the processing system of FIG1. ​​Elements as previously indicated may also be as described.

[0046] Referring to Figure 3, the processing system 300 includes a processing chamber 330, which is fluidly coupled to the mass spectrometer 340 via a beamforming stage 310. The beamforming stage 310 is fluidly coupled to the processing chamber 330 via a first aperture 314, which allows the particle beam to enter a buffer chamber 311 of the beamforming stage 310. A second aperture 315 provides fluid coupling between the shutter chamber 312 of the beamforming stage 310 and the buffer chamber 311. The buffer chamber 311 is emptied using a first outward particle flow 327 generated at a first discharge port 317.

[0047] Optical shutter 320 is contained within optical shutter chamber 312 and serves to block the path 324 of the particle beam in the closed position and to allow the particle beam to reach the interface 344 (and ionizer 346) of the mass spectrometer 340 along the path 325 in the open position. Optical shutter chamber 312 is emptied using a second outward particle stream 328 generated at the second discharge port 318.

[0048] The beam-forming stage 310 further includes a stationary chamber 313, which is fluidly coupled to the shutter chamber 312 via a third aperture 316. As previously mentioned, the ionizer 346 may extend into the stationary chamber 313 to reduce the distance between the ionizer 346 and the third aperture 316. The stationary chamber 313 is discharged using a third outward particle stream 329 generated at the third discharge port 319. In various embodiments, the diameter of the third aperture 316 is larger than the diameter of the second aperture 315, and in one embodiment, it is approximately twice the size of the diameter of the second aperture 315. For example, the diameter of the second aperture 315 may be approximately 35 / 1000 inch (~0.9 mm), while the diameter of the third aperture 316 may be approximately 59 / 1000 inch (~1.5 mm). As previously mentioned, the diameter of the second aperture 315 may also be larger than the diameter of the first aperture 314.

[0049] Similar to the quiescent chamber 313, the buffer chamber 311 can be used to further improve the signal-to-noise ratio in the mass spectrometer 340. Individual evacuation of the buffer chamber 311 lowers the pressure in the shutter chamber 312 than the pressure in the buffer chamber 311. Therefore, the signal-to-noise ratio can be advantageously improved in the mass spectrometer 340. Including the buffer chamber 311 can advantageously extend the operating range of the mass spectrometer 340 of the processing system 300 to include higher pressures in the processing chamber 330. In one embodiment, the mass spectrometer 340 of the processing system 300 is configured to operate at pressures up to 1 Torr.

[0050] The multi-chamber configuration of processing systems 200 and 300 is a specific example of a tandem pressure-reducing chamber. Additional individually emptied chambers may be included when measurements are desired at higher processing chamber pressures. Optical shutters can be included in any tandem pressure-reducing chamber.

[0051] In this specific case, the beam-forming stage 310 includes both the buffer chamber 311 and the stationary chamber 313, but this is not mandatory. For example, in applications where it is desirable to reduce pressure before the shutter chamber but further pressure reduction is not required before the mass spectrometer, the stationary chamber can be omitted. Furthermore, the shutter chamber can be extended, and the shutter can be placed at a suitable distance from the mass spectrometer. Given the entirety of this disclosure, other configurations not explicitly described will become apparent to those skilled in the art.

[0052] As mentioned elsewhere, the processing system described herein can advantageously have a small footprint. For example, the combined length 350 of the buffer chamber 311, the shutter chamber 312, and the stationary chamber 313 can advantageously be small. In various embodiments, the combined length 350 is between about 12 inches and 15 inches, and in one embodiment it is about 13 inches (~330 mm).

[0053] The buffer chamber 311, the shutter chamber 312, and the stationary chamber 313 can advantageously have small volumes. For example, one or more can be implemented using a radial port flange having an outer diameter of less than about 3 inches (e.g., 2.75 inches). In various embodiments, the width 351 of the buffer chamber 311 can be between about 2 inches and about 4 inches, and in one embodiment is about 3 inches (~76 mm). The width 352 of the shutter chamber 312 can also be small, but not necessarily of the same size.

[0054] The width 353 of the stationary chamber 313 can also be small. In some applications, it is advantageous to include additional space between the third aperture 316 and the interface 344 of the mass spectrometer 340 (e.g., to further reduce the influence of the shutter on measurement variability). In these cases, the width 353 can be larger than both widths 351 and 352. In various embodiments, the width 353 can be between about 2 inches and about 6 inches, and in one embodiment it is about 4 inches (~102 mm).

[0055] According to one embodiment of the present invention, FIG4 illustrates a schematic cross-sectional view of another exemplary processing system including a mass spectrometer coupled to a processing chamber via a beamforming stage, which includes a buffer chamber, an optical shutter chamber, and a stationary chamber. For example, the processing system of FIG4 may be a specific implementation of other processing systems described herein, such as the processing system of FIG1. ​​Elements as previously indicated may be as described.

[0056] Referring to Figure 4, the processing system 400 includes a processing chamber 430, which is fluidly coupled to the mass spectrometer 440 via a beam-forming stage 410. The beam-forming stage 410 includes a buffer chamber 411, a shutter chamber 412, and a quiescent chamber 413, which are fluidly coupled to the processing chamber 430 via a first aperture 414, a second aperture 415, and a third aperture 416, respectively. The shutter 420 is used to block the path 424 of the particle beam in a closed position and to allow the particle beam to reach the mass spectrometer 440 (and ionizer 446) along the path 425 in an open position.

[0057] As previously described, each chamber is individually emptied using a first outward particle flow 427 at a first discharge port 417, a second outward particle flow 428 at a second discharge port 418, and a third outward particle flow 429 at a third discharge port 419, in order to facilitate a reduction in chamber pressure from the processing chamber 430 to the mass spectrometer 440.

[0058] While still advantageously keeping the quiescent chamber 413 to a small volume, it may include an extension of the quiescent chamber 413 to further separate the third aperture 416 from the mass spectrometer 440. For example, the diameter 454 of the extension of the quiescent chamber 413 may be small. In various embodiments, the diameter 454 is between about 1 inch and about 2 inches, and in one embodiment it is about 1.575 inches (~40 mm).

[0059] The beam-forming stage 410 may also include an optional ceramic break 422. In one embodiment, the optional ceramic break 422 is included as part of a buffer chamber 411 between the first aperture 414 and the second aperture 415. The optional ceramic break 422 may be included to advantageously electrically insulate the processing chamber 430 (e.g., functioning as a plasma shield) from one or more portions of the beam-forming stage 410 (and the mass spectrometer 440). An optional bias voltage 423 may also be electrically coupled to one or more apertures (here, an example is electrically coupled to the second aperture 415).

[0060] According to one embodiment of the present invention, FIG5 illustrates a schematic arrangement of an exemplary processing system including a mass spectrometer, which is coupled to a processing chamber via a beamforming stage, the beamforming stage including a buffer chamber, a shutter chamber, and a stationary chamber.

[0061] Referring to Figure 5, the processing system 500 includes a processing chamber 530, which is fluidly coupled to the mass spectrometer 540 via a valve 562 (e.g., an electrically operated gate valve). Valve 562 allows particles from the processing chamber 530 to reach a first aperture 514 in a buffer chamber 511 where a particle beam is formed. The particle beam is further focused by a second aperture 515 upon entering a shutter chamber 512.

[0062] Optionally, the ceramic separator 522 may be included before and / or after the second aperture 515. Alternatively, an optional bias source 523 may be used to bias the second aperture 515 (e.g., positive bias) to focus ions in the particle beam and remove spurious electrons. As mentioned above, additional apertures and chambers may also be biased using the optional bias source 523 or additional bias sources.

[0063] Optical shutter 520 is contained within optical shutter chamber 512. Optical shutter 520 may be a double-sided optical shutter, configured to rotate by an electric motor mechanically coupled to optical shutter 520. The particle beam is further focused by entering the stationary chamber 513 through a third aperture 516. Mass spectrometer 540 is fluidly coupled to the stationary chamber 513 and aligned with the particle beam.

[0064] Each of the buffer chamber 511, the shutter chamber 512, and the stationary chamber 513 is individually emptied using a dedicated vacuum pump 564 (e.g., a dedicated turbomolecular pump). Due to the small volume and tandem arrangement of the continuous chambers, the optimal pumping speed of each of the dedicated vacuum pumps 564 is advantageously low. In various embodiments, the pumping speed of each of the dedicated vacuum pumps 564 is less than about 10 L / s, and in one embodiment about 60 L / s. However, the pumping speed can depend on the chamber volume, orifice size, and other factors.

[0065] In some embodiments (e.g., when the processing chamber 530 is operated at higher pressures), an optional coarse pump may be included to ensure that a dedicated vacuum pump can be operated. The pumping rates among the dedicated vacuum pumps 564 may be similar or different and may depend on the specific details of the intended application.

[0066] According to one embodiment of the present invention, FIG6 illustrates a flowchart of an exemplary method for collecting quantized data from a processing chamber using an optical shutter and electron energy sweep. For example, the method of FIG6 can be combined with other methods and implemented using a system as described herein, such as the processing systems of FIG1-5. The method of FIG6 can be combined with any of the embodiments of FIG7-9.

[0067] Referring to Figure 6, method 600 begins with an initial step 671 of initiating data collection via a processing system. The processing system may include a controller coupled to a shutter and a mass spectrometer. The controller may be configured to initiate method 600 by initiating data collection within the processing system. The controller may include a processor and a non-transitory computer-readable medium storing a program containing instructions for performing method 600 when executed. The controller may be implemented as an executable program stored on a non-transitory computer-readable medium of a general-purpose computer. In other embodiments, the controller may be a dedicated controller capable of receiving parameter input from a user interface or an external source (e.g., a connected computer).

[0068] Step 601 of method 600 involves closing the optical shutter to block the particle beam from reaching the mass spectrometer. Next, in step 602, the electron energy of the ionizer of the mass spectrometer is set to an initial energy value. Optionally, an initial baseline can then be collected as a reference point for data collection.

[0069] After collecting or omitting the initial baseline, a series of steps are performed cyclically as an electron energy sweep. In step 604, data is collected with the optical shutter closed. Because the optical shutter is closed, the data collected in step 604 includes background quantization data. That is, the particle beam is blocked by the optical shutter, and only particles that are not part of the coherent beam can reach the mass spectrometer.

[0070] After collecting background quantization data in step 604, the shutter is opened in step 605, and data is collected with the shutter open in step 606. The data collected in step 606 includes quantization data of the particle beam (e.g., signal data) and data generated by the background. After collecting signal quantization data, the shutter is closed again.

[0071] In step 607, the processing system checks whether the electron energy is equal to a predetermined final value. If not, in step 608, the electron energy is set to the next energy stage, and the cycle restarts, with background data being collected again in step 604. In this way, the cyclic data collection procedure proceeds stepwise through a range of electron energy, starting from an initial energy value and performing data collection cycles for each of the multiple energy stages.

[0072] If, in step 607, the processing system determines that the electron energy equals the final energy, it exits the loop, and the energy is optionally set back to the initial energy value so that a tail-end baseline can be optionally collected in step 609. Data collection then ends in step 672. Without collecting the tail-end baseline, method 600 can proceed directly from step 607 to step 672 after determining that data has been collected for the final energy value. Collecting the tail-end baseline (i.e., after data collection) can be beneficial when measuring high-density gas / plasma from the processing chamber to correct for baseline shifts caused by charging in the mass spectrometer during continuous use and to verify the processing chamber stability of the entire data collection procedure.

[0073] The duration of the data collection steps (steps 604 and 606) can advantageously be short. In various embodiments, this duration is less than about 30 seconds, and in some embodiments less than about 10 seconds. For example, the duration can be between about 0.1 seconds and about 50 seconds. In one embodiment, the duration is about 10 seconds.

[0074] The electron energy scanning method 600 can be advantageously automated. Background and baseline data can be automatically used to limit diagnostic errors in the system caused by contamination or drift. Qualitative and quantitative analysis of the data can also be performed automatically. In this way, the necessary knowledge and effort required by process engineers to obtain diagnostic information is advantageously reduced. Automated diagnostics can also bring the additional benefit of reducing human error. Furthermore, multiple electron energy scans can be batch-processed to generate a comprehensive diagnostic report for a given process.

[0075] According to one embodiment of the present invention, Figure 7 illustrates two graphs qualitatively showing an exemplary method for collecting quantitative data from a processing chamber to measure the number of species in the processing chamber by using an optical shutter and electron energy sweeping. For example, the method of Figure 7 can be combined with other methods and implemented using systems as described herein, such as the processing systems of Figures 1-5. The method of Figure 7 can be combined with any of the embodiments of Figures 6, 8, and 9.

[0076] Referring to Figure 7, graph 701 qualitatively displays data points of signal 781 measured by the mass spectrometer of the processing system during data collection (e.g., data collection as described in method 600 of Figure 6). Signal 781 comprises both background quantized data and signal quantized data. The source of the signal quantized data is the particle beam originating from the processing chamber of the processing system, but it also includes background signals from particles originating from the mass spectrometer itself rather than from the processing chamber.

[0077] As previously described, the data collection steps are performed alternately as the electron energy of the ionizer in the mass spectrometer gradually increases during the complex energy phase from the initial energy value to the final energy value. As shown in the figure, while the shutter of the processing system remains closed, a series of data points 784 corresponding to the background signal quantization data are collected during each step 704. Similarly, while the shutter remains open, a series of data points 786 corresponding to the signal quantization data are collected during each step 706.

[0078] Data points from a series of electron energy sweeps are processed to produce a data set 782 as shown in qualitative chart 702. For example, the average background data points 784 of each series can be averaged to obtain an average background data point, which can be subtracted from the corresponding average signal data points obtained by averaging the data points 786 of each series. In this way, transient background effects in the mass spectrometer can be taken into account by subtracting the temporal local background data from each signal data point, thereby advantageously improving the accuracy of the data set 782.

[0079] During data collection to generate dataset 782, an electromagnetic filter (e.g., a quadrupole analyzer for an RGA) is adjusted to a specific mass / charge ratio (e.g., a specific mass value when all detected species have a charge of +1). Therefore, each data point in dataset 782 represents a particle signal with the same m / z. The filter mass can also be swept during data collection. For example, for each energy stage, the filter mass can be progressively increased from an initial mass value to a final mass value (e.g., when prioritizing comparative results), or the filter mass can remain constant for the entire electron energy sweep and then progressively increase to a new filter mass value for a new electron energy sweep (e.g., when prioritizing the timeliness of the results).

[0080] Data set 782 can be used to detect several species located in the mass spectrometer. For example, once the electron energy reaches the critical ionization energy 794 of the species (e.g., 11.62 eV for C₂H⁺ e⁻ → C₂H⁺ ⁻ 2e⁻), the ionized species (e.g., C₂H⁺) is detected by the mass spectrometer (adjusted to m / z = 25). Therefore, a first interval 791 starting from the critical ionization energy 794 can be used to determine quantitative information about the species (C₂H⁺ in this specific example). For example, the data points within the first interval 791 can be compared with the theoretical ionization curve 796 (shown as a linear curve here for simplicity, but any curve, including empirically derived curves, can be used). Thus, the species detected within the first interval 791 is the first species originating from the particle beam in the processing chamber, which is subsequently ionized in the mass spectrometer (e.g., the ionized species).

[0081] This technique can also be used to detect other species. Specifically, once the electron energy reaches the species' critical dissociation energy of 795 eV (e.g., 17.22 eV for C₂H₂⁺ e⁻ → C₂H⁺ + H⁺ + 2e⁻), the dissociated (and ionized) species (e.g., C₂H⁺) is detected by mass spectrometry (e.g., using the inflection point in a signal versus electron energy graph). The dissociation energy can be approximately equal to the critical dissociation energy of 794 plus the energy required to break the bond and dissociate the unfractured species (in this case, C₂H₂).

[0082] Therefore, data points within a second interval 792, starting from the critical dissociation energy 795, can be used to determine quantitative information about the species (C₂H in this specific example). As described above, data points within the second interval 792 can be compared with the theoretical dissociation curve 797 to detect a second species originating from the mass spectrometer itself (e.g., background particles after the second species has fragmented in the mass spectrometer; dissociated species). Thus, species originating from the processing chamber can be advantageously distinguished from species originating from the mass spectrometer.

[0083] For energies below the critical ionization energy 794 within the third interval 793, a third variety of species can be detected in a similar manner. For example, the species may also exist in the processing chamber as metastable particles (e.g., in an excited state). Due to the increased energy level of one or more electrons of the metastable particle, the critical metastable ionization energy is lowered compared to the critical ionization energy 794 (e.g., < 11.62 eV for C 2H *+ e -→ C 2H ++ 2e -) to continue the above paradigm. Therefore, metastable varieties of the species can be advantageously distinguished within the third interval 793. Conversely, processing systems containing conventionally implemented mass spectrometers cannot distinguish metastable varieties. As described for other varieties, data points within the third interval 793 can be compared with the theoretical metastable curve 798 to detect a third variety of the species, which is a metastable particle in an excited state originating from the processing chamber.

[0084] As can be seen in qualitative chart 702, signals from earlier intervals can overlap with signals from other species in later intervals. These contributions can be adjusted (e.g., using extrapolation and / or theoretical techniques). Furthermore, while the above examples focus on detecting neutral species, ions can also be detected (but with z > 1). In some cases, ions originating from the processing chamber are intentionally removed (e.g., using ceramic separators and / or electrical bias).

[0085] According to one embodiment of the present invention, FIG8 illustrates an exemplary method for measuring the quantity of species present in a processing chamber using collected quantitative data. For example, the method of FIG8 can be combined with other methods and performed using a system as described herein, such as the processing system of FIG1-5. The method of FIG8 can be combined with any embodiment of FIG6, 7, and 9. Although shown in logical order, the arrangement and numbering of the steps in FIG8 are not intended to be limiting. The various steps in the method of FIG8 can be performed in any suitable order or simultaneously with each other, as will be apparent to those skilled in the art.

[0086] Referring to Figure 8, step 801 of method 800 for measuring the number of species present in a processing chamber includes closing an optical shutter positioned between the processing chamber and the mass spectrometer to block the particle beam originating from the processing chamber. The mass spectrometer includes an ionizer. Step 802 involves setting the electron energy of the ionizer to an initial energy value.

[0087] Step 803 includes repeatedly (i.e., cyclically) collecting background quantization data when the shutter is closed, opening the shutter, collecting signal quantization data of the species in the particle beam when the shutter is open, closing the shutter, and setting the electron energy to the next value to sweep electron energy from the initial energy value to the final energy value.

[0088] After collecting signal quantization data with electron energy set at the final energy value, step 804 will use the signal quantization data and background quantization data to determine the number of species in the processing chamber.

[0089] According to one embodiment of the present invention, FIG9 illustrates an exemplary method for measuring the quantity of species present in a processing chamber using electron energy scanning. For example, the method of FIG9 can be combined with other methods and performed using a system as described herein, such as the processing systems of FIG1-5. The method of FIG9 can be combined with any of the embodiments of FIG6-8. Although shown in logical order, the arrangement and numbering of the steps in FIG9 are not intended to be limiting. The various steps in the method of FIG9 can be performed in any suitable order or simultaneously with each other, as will be apparent to those skilled in the art.

[0090] Referring to Figure 9, step 901 of the method 900 for measuring the number of species present in the processing chamber includes sweeping the electron energy of the ionizer of the mass spectrometer during a complex energy phase that begins at an initial energy value and ends at a final energy value. In step 902, a data set is generated by collecting a series of data points corresponding to the detection event of a species at each of the complex energy phases. The species includes the mass / charge ratio selected by the mass spectrometer.

[0091] Step 903 uses the first interval of the data set starting from the critical free energy of the first variety to determine the quantity of the first variety of the species present in the processing chamber. The first variety also has the same mass / charge ratio. That is, all varieties of the species have the same mass / charge ratio.

[0092] Exemplary embodiments of the present invention are summarized herein. Other embodiments may also be understood from the entire specification and the claims made herein.

[0093] Example 1. A plasma processing system includes: a plasma chamber configured to contain plasma; a shutter chamber fluidly coupled to the plasma chamber via a first orifice, the first orifice being configured to generate a particle beam from the plasma using a pressure difference between the shutter chamber and the plasma chamber; a mass spectrometer fluidly coupled to the shutter chamber, the mass spectrometer including an ionizer configured to ionize species of the particle beam by sweeping through an electron energy range in a complex energy phase; and a shutter disposed in the shutter chamber between the first orifice and the mass spectrometer and located in the path of the particle beam, the shutter being configured to open and close during each of the complex energy phases.

[0094] Example 2. The plasma processing system of Example 1 further includes: a stationary chamber disposed between the shutter chamber and the mass spectrometer, the stationary chamber being fluidly coupled to the shutter chamber via a second orifice located in the path of the particle beam; a first vacuum pump fluidly coupled to the shutter chamber; and a second vacuum pump fluidly coupled to the stationary chamber.

[0095] Example 3. The plasma processing system of Example 2 further includes: a buffer chamber disposed between the plasma chamber and the shutter chamber, the buffer chamber being fluidly coupled to the plasma chamber via a third orifice; a third vacuum pump fluidly coupled to the buffer chamber; and wherein the diameter of the third orifice is smaller than the diameter of the first orifice, and the diameter of the first orifice is smaller than the diameter of the second orifice.

[0096] Example 4. The plasma processing system of Example 3, wherein both the shutter chamber and the buffer chamber are radial flanges with an outer diameter of less than about three inches.

[0097] Example 5. The plasma processing system of Example 3, wherein the combined length of the buffer chamber, the shutter chamber, and the stationary chamber along a direction parallel to the path of the particle beam is less than fifteen inches.

[0098] Example 6. The plasma processing system of one of Examples 1 to 5 further includes: a ceramic separator disposed between the plasma chamber and the first orifice.

[0099] Example 7. The plasma treatment system of Example 6 further includes: an electrical bias source electrically coupled to the first orifice.

[0100] Example 8. A plasma processing system of one of Examples 1 to 7, wherein the shutter is a double-sided shutter and the shutter is configured to rotate by an electric motor mechanically coupled to the shutter.

[0101] Example 9. A plasma processing system of one of Examples 1 to 8, wherein the shutter chamber comprises a radial flange with an outer diameter of less than about three inches.

[0102] Example 10. A plasma processing system of one of Examples 1 to 9, wherein the path of the particle beam is a straight line from the plasma chamber to the mass spectrometer.

[0103] Example 11. A plasma processing system of one of Examples 1 to 10, wherein the mass spectrometer is a residual gas analyzer (RGA) mass spectrometer.

[0104] Example 12. A method for measuring the number of species in a processing chamber, the method comprising the steps of: closing a shutter disposed between a processing chamber and a mass spectrometer to block a particle beam originating from the processing chamber, the mass spectrometer including an ionizer; setting the electron energy of the ionizer to an initial energy value; sweeping the electron energy from the initial energy value to a final energy value by cyclically performing the following steps: collecting background quantization data while the shutter is closed, opening the shutter, collecting signal quantization data of species in the particle beam while the shutter is open, closing the shutter, and setting the electron energy to a next value; and after collecting signal quantization data at the electron energy set to the final energy value, using the signal quantization data and the background quantization data to determine the number of species in the processing chamber.

[0105] Example 13. The method of Example 12 further includes: collecting initial baseline quantization data after setting the electron energy to the initial energy value and before sweeping the electron energy; and the step of determining the number of the species in the processing chamber further includes using the initial baseline quantization data.

[0106] Example 14. The method of Example 13 further includes, after collecting the signal quantization data at the electron energy set at the final energy value and before determining the number of species in the processing chamber: setting the electron energy to the initial energy value; collecting tail baseline quantization data; and wherein the step of determining the number of species in the processing chamber further includes using the tail baseline quantization data.

[0107] Example 15. The method of one of Examples 12 to 14, wherein the duration of each quantization data collection step during the sweep of the electron energy is less than about ten seconds.

[0108] Example 16. The method of one of Examples 12 to 15 further includes: sweeping a filter mass of the mass spectrometer from an initial mass value to a final mass value.

[0109] Example 17. A method for measuring the quantity of a species present in a processing chamber, the method comprising the steps of: sweeping the electron energy of an ionizer of a mass spectrometer during a complex energy phase beginning at an initial energy value and ending at a final energy value; generating a data set by collecting a series of data points corresponding to a detection event of the species at each of the complex energy phases, the species comprising a mass / charge ratio selected by the mass spectrometer; and determining the quantity of the first variety of the species present in the processing chamber, the first variety having the mass / charge ratio, using a first interval of the data set beginning at a critical ionization energy of a first variety of the species.

[0110] Example 18. The method of Example 17, wherein, for each of the complex energy stages, the step of generating the data set comprises: closing a shutter disposed between the processing chamber and the mass spectrometer to block a particle beam originating from the processing chamber; collecting a series of background data points while the shutter is closed; opening the shutter to allow the particle beam to reach the mass spectrometer; collecting a series of signal data points while the shutter is open; and subtracting the average value of the series of background data points from the average value of the series of signal data points.

[0111] Example 19. The method of one of Examples 17 and 18 further comprises: using a second interval of the data set starting from a critical dissociation energy of a second variety of the species to determine the quantity of the second variety of the species present in the processing chamber, the second variety having the mass / charge ratio.

[0112] Example 20. The method of one of Examples 17 to 19 further comprises: using a second interval of the data set ending at the ionization energy of the first variety to determine the quantity of a second variety of the species present in the processing chamber, the second variety having the mass / charge ratio; wherein the first variety of the species is a stable particle from plasma in the processing chamber; and wherein the second variety of the species is a metastable particle in an excited state of the stable particle from plasma.

[0113] While the invention has been described with reference to exemplary embodiments, this description is not to be construed as limiting. Those skilled in the art will understand, upon referring to this description, various modifications and combinations of these exemplary embodiments, as well as other embodiments of the invention. Therefore, it is intended that the appended claims include any such modifications or embodiments.

[0114] 100: Processing System 110: Bundle Formation Stage 112: Vacuum Chamber 114: Orifice 118: Emission outlet 120: Light shutter 124: Path 125: Path 128: Outward Particle Flow 130: Processing Chamber 140: Mass spectrometer 144: Interface 146: Ionizer 200: Processing System 210: Bundle Formation Stage 212: Optical shutter chamber 213:Static chamber 214: First Orifice 215: Second orifice 218: First discharge port 219: Second emission outlet 220: Light shutter 224: Path 225: Path 228: First Outward Particle Flow 229: Second outward particle flow 230: Processing Chamber 240: Mass spectrometer 244: Interface 246: Ionizer 300: Processing System 310: Bundle Formation Stage 311: Buffer Chamber 312: Optical shutter chamber 313:Static chamber 314: First orifice 315: Second orifice 316: Third orifice 317: First discharge port 318: Second emission outlet 319: Third emission outlet 320: Optical shutter 324: Path 325: Path 327: First Outward Particle Flow 328: Second outward particle flow 329: Third Outward Particle Flow 330: Processing Chamber 340: Mass spectrometer 344: Interface 346: Ionizer 350: Combination length 351: Width 352: Width 353: Width 400: Processing System 410: Bundle Formation Stage 411: Buffer Chamber 412: Optical shutter chamber 413: Still chamber 414: First orifice 415: Second orifice 416: Third orifice 417: First discharge port 418: Second emission outlet 419: Third emission outlet 420: Optical shutter 422: Ceramic partition 423: Electrical bias voltage 424: Path 425: Path 427: First outward particle flow 428: Second outward particle flow 429: Third Outward Particle Flow 430: Processing Chamber 440: Mass spectrometer 446: Ionizer 454: Diameter 500: Processing System 511: Buffer Chamber 512: Optical shutter chamber 513: Still chamber 514: First Orifice 515: Second orifice 516: Third orifice 520: Light Shutter 522: Ceramic Partition 523: Electrical bias source 530: Processing Chamber 540: Mass spectrometer 562: Valve 564: Dedicated Vacuum Pump 600: Method 601: Steps 602: Steps 604: Steps 605: Steps 606: Steps 607: Steps 608: Steps 609: Steps 671: Initial Steps 672: Steps 701: Chart 702: Qualitative Charts 704: Steps 706: Steps 781: Signal 782: Data Set 784: Data Points 786: Data Points 791: First Interval 792: Second Interval 793: Third Interval 794: Critical Free Energy 795: Critical dissociation energy 796: Theoretical Free Curve 797: Theoretical dissociation curve 798: Theoretical Metastable Curve 800: Method 801: Steps 802: Steps 803: Steps 804: Steps 900: Method 901: Steps 902: Steps 903: Steps

Claims

1. A plasma processing system comprising: a plasma chamber configured to contain plasma; a shutter chamber fluidly coupled to the plasma chamber via a first orifice, the first orifice being configured to generate a particle beam from the plasma using a pressure difference between the shutter chamber and the plasma chamber; a mass spectrometer fluidly coupled to the shutter chamber, the mass spectrometer including an ionizer configured to ionize species of the particle beam by sweeping through an electron energy range in a complex energy phase; and a shutter disposed in the shutter chamber between the first orifice and the mass spectrometer and located in the path of the particle beam, the shutter being configured to open and close during each of the complex energy phases.

2. The plasma processing system as claimed in claim 1 further comprises: a stationary chamber disposed between the shutter chamber and the mass spectrometer, the stationary chamber being fluidly coupled to the shutter chamber via a second orifice located in the path of the particle beam; a first vacuum pump fluidly coupled to the shutter chamber; and a second vacuum pump fluidly coupled to the stationary chamber.

3. The plasma processing system as claimed in claim 2 further comprises: a buffer chamber disposed between the plasma chamber and the shutter chamber, the buffer chamber being fluidly coupled to the plasma chamber via a third orifice; a third vacuum pump fluidly coupled to the buffer chamber; and wherein the diameter of the third orifice is smaller than the diameter of the first orifice, and the diameter of the first orifice is smaller than the diameter of the second orifice.

4. The plasma processing system as claimed in claim 3, wherein both the shutter chamber and the buffer chamber are radial flanges having an outer diameter of less than about three inches.

5. The plasma processing system as claimed in claim 3, wherein the combined length of the buffer chamber, the shutter chamber, and the stationary chamber along a direction parallel to the path of the particle beam is less than fifteen inches.

6. The plasma processing system as claimed in claim 1 further comprises: a ceramic separator disposed between the plasma chamber and the first orifice.

7. The plasma processing system as described in claim 6 further includes: an electrical bias source electrically coupled to the first orifice.

8. The plasma processing system as claimed in claim 1, wherein the shutter is a double-sided shutter and the shutter is configured to rotate by an electric motor mechanically coupled to the shutter.

9. The plasma processing system as claimed in claim 1, wherein the shutter chamber comprises a radial flange having an outer diameter of less than about three inches.

10. The plasma processing system as claimed in claim 1, wherein the path of the particle beam is a straight line from the plasma chamber to the mass spectrometer.

11. The plasma processing system as claimed in claim 1, wherein the mass spectrometer is a residual gas analyzer (RGA) mass spectrometer.

12. A method for measuring the number of species in a processing chamber, the method comprising the steps of: closing a shutter disposed between a processing chamber and a mass spectrometer to block a particle beam originating from the processing chamber, the mass spectrometer including an ionizer; setting the electron energy of the ionizer to an initial energy value; sweeping the electron energy from the initial energy value to a final energy value by cyclically performing the following steps: collecting background quantization data while the shutter is closed; opening the shutter; collecting signal quantization data of species in the particle beam while the shutter is open; closing the shutter and setting the electron energy to a next value; and after collecting signal quantization data at the electron energy set to the final energy value, using the signal quantization data and the background quantization data to determine the number of species in the processing chamber.

13. The method for measuring the number of species in a processing chamber as described in claim 12, further comprising: collecting initial baseline quantization data after setting the electron energy to the initial energy value and before sweeping the electron energy; and wherein the step of determining the number of species in the processing chamber further comprises using the initial baseline quantization data.

14. The method for measuring the number of species in a processing chamber as described in claim 13, further comprising, after collecting the signal quantization data at an electron energy set at the final energy value and before determining the number of species in the processing chamber: setting the electron energy to the initial energy value; collecting tail baseline quantization data; and wherein the step of determining the number of species in the processing chamber further comprises using the tail baseline quantization data.

15. The method for measuring the number of species in a processing chamber as described in claim 12, wherein the duration of each quantization data collection step during the sweeping of electron energy is less than about ten seconds.

16. The method for measuring the number of species in a processing chamber as described in claim 12 further comprises: sweeping a filtration mass of the mass spectrometer from an initial mass value to a final mass value.

17. A method for measuring the quantity of a species present in a processing chamber, the method comprising the steps of: sweeping electron energies of an ionizer of a mass spectrometer during a complex energy phase beginning at an initial energy value and ending at a final energy value; generating a data set by collecting a series of data points corresponding to a detection event of the species at each of the complex energy phases, the species comprising a mass / charge ratio selected by the mass spectrometer; determining the quantity of a first variety of the species present in the processing chamber, the first variety having the mass / charge ratio, using a first interval of the data set beginning at a critical ionization energy of a first variety of the species; and determining the quantity of a second variety of the species present in the processing chamber, the second variety having the mass / charge ratio, using a second interval of the data set.

18. The method for measuring the quantity of species present in a processing chamber as described in claim 17, wherein, For each of the complex energy stages, the steps of generating the data set include: closing a shutter disposed between the processing chamber and the mass spectrometer to block a particle beam originating from the processing chamber; collecting a series of background data points while the shutter is closed; opening the shutter to allow the particle beam to reach the mass spectrometer; collecting a series of signal data points while the shutter is open; and subtracting the average of the series of background data points from the average of the series of signal data points.

19. The method for measuring the number of species present in a processing chamber as described in claim 17, wherein the second interval of the data set begins at one of the critical dissociation energies of the second species.

20. The method for measuring the quantity of a species present in a processing chamber as described in claim 17, wherein the second interval of the data set ends at the critical ionization energy of the first species; wherein the first species of the species is a stable particle from plasma in the processing chamber; and wherein the second species of the species is a metastable particle in an excited state of the stable particle from plasma.

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