HYDROGEN FLUORIDE DETECTION USING MASS SPECTROMETRY

Systems and methods are described that facilitate effective detection and quantification of hydrogen fluoride within a sample utilizing mass spectrometry (MS). A MS analysis is performed on a gas sample to obtain an unfiltered set of MS signal data. Hydrogen fluoride (HF) is removed from the gas sample by filtration to form a HF filtered gas sample, and MS analysis is performed on the HF filtered gas sample to obtain a filtered set of MS signal data. The filtered set of MS signal data is compared with the unfiltered set of MS signal data, and a presence and/or concentration of HF within the gas sample is determined based upon the comparison.

FIELD

The present invention relates to detection of gaseous components using mass spectrometric analysis methods.

BACKGROUND

Mass spectrometry has been a long-standing analytical technique for gas analysis with applications across a diverse range of industries. The wide-spread application of mass spectrometry is largely due to its ability to quantify a wide range of analytes that include volatile organic and inorganic compounds with a high degree of specificity. The specificity of mass spectrometry can be achieved by control of the analyte ionization mechanism, and by precise measurement of an analyte ion's mass-to-charge ratio.

Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS) is a form of direct chemical ionization mass spectrometry that has the advantages of a very soft ionization mechanism as well as the use of up to 8 different reagent ions to provide multiple ionization channels for a single analyte. This combination of features allows for real-time analysis with low detection limits and generally high selectivity when compared to other real time MS techniques.

Across the trace gas analysis industry, it is challenging to measure hydrogen fluoride (HF) with high selectivity and low detection limits while retaining simultaneous measurement capabilities for other compounds. For example, SIFT-MS can quantify HF by utilizing soft-ionization reactions with several different reagent ions, including (without limitation)O−and OH−, which both react with HF by a proton transfer mechanism to form the product ion F−at m/z=−19. Other compounds that react with these reagent ions to form a fluoride ion will cause a spectral interference with HF and include many classes of fluorine-containing compounds including perfluorocarbons (PFCs), hydrofluorocarbons (HFCs), perfluoroalkyl amines, and inorganic fluorides. The efficiency of fluoride ion generation for many of these potential interferents is typically low. However, due to the properties of these compounds (many of which are used in heat transfer systems), such compounds may be present in bulk quantities in fabrication environments (e.g., within clean rooms of semiconductor fabrication facilities). When trace levels of HF need to be reliably quantified, the contributions of these interferent compounds can be significant. Therefore, the selective quantification of hydrogen fluoride relies on an approach that accounts for the contribution of these other compounds to the m/z=−19 signal.

In SIFT-MS analysis, spectral interferences from known compounds with unique product ions are typically removed by subtraction. This approach works well when interferent compounds are limited in number and can be well-characterized. However, in a matrix where there is the potential presence of several different fluorinated compounds, this process cannot be pragmatically applied as it requires significant measurement time which comes at the cost of overall detection limits. Additionally, in matrices where not all interferences are known or no other product ions are viable for subtraction, subtraction will not remove all possible false positives. For example, in a semiconductor fabrication environment, there are both unknown fluorine-containing compounds present and compounds such as nitrogen trifluoride (NF3) that do not produce unique product ions compared to HF, the subtraction approach is not viable. As a result, deployment of SIFT-MS in semiconductor fabrication environments have not provided a satisfactory solution to date due to an unacceptably high level of false positive HF events.

With the previously noted issues in mind, it is challenging for the gas analysis industry to measure hydrogen fluoride (HF) with high selectivity and low detection limits while retaining simultaneous measurement capabilities for other compounds. It is often important to provide an accurate presence determination and measurement of HF concentration in certain industrial and/or manufacturing environments (e.g., in clean rooms of semiconductor manufacturing/fabrication facilities). Hydrogen fluoride has a simple molecular structure with a single bond between hydrogen and fluoride. The quantification of HF is typically based on a non-specific fluoride ion (F−) measurement. In other words, the F−measurement contains no information about the bond from where it was previously present (could be HF or some other fluoride compound). This results in a lack of confidence that the qualification and quantification measurement is in fact HF and not another fluorinated compound.

It is therefore desirable to provide a mass spectrometric configuration that accurately identifies the presence and amount of HF in a particular environment.

SUMMARY

In accordance with example embodiments of the invention, a method for detection of hydrogen fluoride (HF) within a gas sample comprises performing mass spectrometry (MS) analysis on a gas sample to obtain an unfiltered set of MS signal data, removing hydrogen fluoride (HF) from the gas sample by filtration to form a HF filtered gas sample, performing mass spectrometry (MS) analysis on the HF filtered gas sample to obtain a filtered set of MS signal data, comparing the filtered set of MS signal data with the unfiltered set of MS signal data, and determining a presence and/or concentration of HF within the gas sample based upon the comparison.

In other example embodiments, a mass spectrometry (MS) detection system with hydrogen fluoride (HF) specificity comprises a MS detector to analyze a gas sample and determine presence and/or concentration of a plurality of chemical species within the gas sample, at least one sample flow line to facilitate flow of the gas sample from a sample source at a selected environment to an inlet of the MS detector, and a selective hydrogen fluoride scrubber coupled with the sample flow line, where the scrubber filters hydrogen fluoride (HF) from the gas sample prior to delivery to the inlet of the MS detector. The system is configured to selectively permit a switch between a first flow of unfiltered gas sample to the inlet of the MS detector and a second flow of HF filtered gas sample to the inlet of the MS detector.

In further example embodiments, a mass spectrometry (MS) detection system with hydrogen fluoride (HF) specificity comprises a MS detector to analyze a gas sample to determine presence and/or concentration of chemical species within the gas sample, a sample flow line that provides the gas sample from a selected environment to the MS detector, the sample flow line including a diverter to selectively divert the gas sample between a first sample line and a second sample line, where each of the first and second sample lines provide the gas sample to a MS inlet of the MS detector, and a selective hydrogen fluoride scrubber (SHFS) provided in the second sample line, where the SHFS filters hydrogen fluoride (HF) from the gas sample prior to delivery to the inlet of the MS detector. The system further comprises a controller that selectively controls the MS detector so as to facilitate delivery and analysis of the gas sample to the MS inlet in an unfiltered state via the first sample line and delivery and analysis of the gas sample to the MS inlet in a filtered state via the second sample line, wherein the controller further facilitates a determination of HF presence and/or HF concentration within the gas sample based upon a comparison of MS analysis of the sample gas in the unfiltered state and MS analysis of the sample gas in the filtered state.

The above and still further features and advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodiments thereof.

DETAILED DESCRIPTION

The terms “comprising,” “including,” “having,” and the like, as used with respect to embodiments of the present disclosure, are synonymous.

In accordance with example embodiments, systems and methods are described herein that facilitate accurate and reliable detection and quantification of hydrogen fluoride (HF) in a sample, particularly when the sample includes other interfering fluoride species and/or other (e.g., non-fluorine) compounds that can interfere with HF detection and quantification. The systems and methods provide for mass spectrometric analysis of a sample and also a modified sample in which HF is selectively removed (e.g., via a scrubber/filtration) from the sample. The sample and modified (HF removed) samples are compared to determine whether and to what extent HF is present within the sample.

The use of a chemical scrubber or filtration unit that selectively removes the highly reactive HF molecule from a sample stream, but not the less reactive compounds that cause spectral interferences, provides an additional and more selective method for HF quantification by MS techniques such as SIFT-MS. This approach does not require detailed knowledge of all the interfering compounds present in the sample stream to selectively report an HF concentration. A viable scrubber substrate is described herein that removes HF from a sample gaseous stream but allows the majority of other fluorine-containing compounds to pass through the scrubber substrate. The scrubber substrate allows HF to be selectively quantified by monitoring the difference between a scrubbed/filtered and non-scrubbed/unfiltered sample stream.

An example and nonlimiting embodiment of a mass spectrometric detection system is depicted inFIG.1. The detection system100comprises a mass spectrometry detector105that receives a gas sample and performs mass spectrometry analysis of the sample to determine chemical compounds/chemical species within the sample by ionization of such compounds performing identification/quantification analysis based upon the mass-to-charge ratio of the ionized compounds.

An example embodiment of a detector105that can be implemented for use in the system100is a mass spectrometry system that utilizes Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS). A non-limiting example SIFT-MS mass spectrometry detector that can be used in the system is a Voice200infinity mass spectrometer detector commercially available from Syft Technologies (New Zealand). The SIFT-MS detector allows mass spectrometry to be applied in applications requiring real-time analysis with low detection limits, e.g., to the parts-per-billion (ppb) and parts-per-trillion (ppt) levels.

A gas sample flow line110receives an input gas from a sample source and directs the gas to an inlet130of the detector105in a manner as described herein. A carrier gas (e.g., ultra-high purity helium or nitrogen) can be utilized to transport the sample within the system. The sample source can be a processing room (e.g., clean room) of a semiconductor manufacturing or fabrication facility that manufactures or processes one or more semiconductor components. In such facilities, hydrogen fluoride (HF) can be used (e.g., as an etchant) and can be present within the room. The gas sample flow line110can selectively acquire a gas sample from the room and deliver the sample to the system100.

Disposed within the gas sample flow line110is a diverter comprising a tee member115and a 3-way valve125. The diverter is provided to selectively divert flow of the gas sample from the sample source to the detector inlet130so as to either bypass a filter or scrubber or facilitate passage through the scrubber as described herein. The tee member115(e.g., a PFA plastic tee fitting) splits the sample from flow line110into two flowing sample streams that flow through sample lines116,122. A first stream flowing within a first sample flow line116proceeds from the tee member115directly to the detector inlet130, while a second stream from a second sample flow line122is first directed from the tee member115through a scrubber or filter120prior to being directed to the detector inlet so as to provide a filtered sample to the detector for analysis. A 3-way valve125is provided in-line with and at the outlets for each of the first sample flow line116and the second sample flow line122. The valve125can be controlled (e.g., automatically controlled via a controller/processor of the detector105as described herein) so as to selectively provide either a first, unfiltered sample stream from the first sample flow line116or the second, filtered sample stream from the second sample flow line122to the detector inlet130.

Any other suitable fitting or combination of fittings or other structure can also be provided to selectively divert the gas sample into two or more (e.g., multiple) sample streams to accommodate filtering and/or other types of processing of the sample prior to analysis by the detector. For example, while the 3-way valve125is depicted in the system100ofFIG.1as being located downstream from the diverter/tee member115, other embodiments for the system are also possible in which the positioning of the 3-way valve125and tee115are reversed (i.e., the 3-way valve is upstream from the tee). Further, the system100depicts a single gas sample flow line that directs a flow of the gas sample from the gas sample source to the system. Alternatively, two separate and independent sample flow lines, with one sample flow line not including any scrubber or filter and the other sample flow line including the scrubber or filter, can be provided from the sample source (e.g., a manufacturing or processing room for semiconductor fabrication) to the detector, where each sample flow line can be adjusted via one or more valves to selectively permit or prevent flow into the detector (thus facilitating flow of filtered or unfiltered gas sample to the detector).

A reagent ion generator/reagent ion supply source170generates and delivers any selected number and types of reagent ions (e.g., NO+, O2+, H3O+, O−, O2−, OH−, NO2−and/or NO3−) in a carrier medium (e.g., nitrogen) within a reaction chamber within the detector, where the reaction chamber also receives the sample delivered from the detector inlet130. For example, the reagent ion generator and supply source for a SIFT-MS detector (e.g., a Voice200infinity mass spectrometer detector as described herein) can comprise a microwave discharge component that generates reagent ions of the types noted herein from a gas supply mixture of air or oxygen (O2), water (H2O) and nitrogen (N2) (where the gas supply also functions as a carrier medium for the reagent ions formed). The SIFT-MS detector further includes a quadrupole filter to selectively deliver one or more types of the generated reagent ions for entry into the reaction chamber (while preventing others from entering the reaction chamber). This facilitates exposure and selective reaction (utilizing SIFT-MS) within the reaction chamber of the detector of the one or more selected reagent ions with one or more chemical compounds within the sample to form reaction products. For example, OH−ions selectively permitted to enter the reaction chamber within the MS detector react with HF within the gas sample to generate one or more ionization products that are detectable, identifiable and quantifiable by MS analysis within the detector.

The detector105performs mass spectrometry analysis of the sample including reaction products (from the reaction of one or more reagent ions with chemical compounds in the sample) and then outputs the analyzed sample via an outlet140and through a flow line150. A pump145can be provided in-line along the flow line150to direct the analyzed sample (for collection or to a selected exhaust system). A back pressure regulator142can also be provided in the flow line150to control pressure and flow of the sample into and through the detector.

The detector105can include a controller or processor160and memory162to store any one or more applications for processing data collected by the detector during the sample analysis. The processor160can comprise a microprocessor that executes control process logic instructions stored within the memory162, including operational instructions and one or more software applications stored within such memory, where the processor160(utilizing the one or more software applications) performs operations in accordance with the operational/method steps described herein for mass spectrometry and analysis of gas samples.

The memory162of the detector105can include a library of data including known (i.e., “fingerprint”) m/z signal data for analyses of various specific chemical components based upon a particular application. Alternatively, or in addition to a data library provided in the memory162of the detector105, the detector105can further include a suitable network interface164that facilitates communications and exchange of data between the detector105and other computing systems over any suitable type of wired and/or wireless network (e.g., any one or more of local or wide area networks, Internet Protocol (IP) networks such as intranet or internet networks, telephone networks (e.g., public switched telephone networks), wireless or mobile phone or cellular networks, and any suitable combinations thereof). The detector105can further include any one or more suitable types of peripheral device interfaces (PDIs)166that facilitate a hardwire connection or other coupling (e.g., wireless) with the detector (e.g., keyboard, display, mouse device, microphone device, audio device, etc.) so as to facilitate exchange of data (I/O operations) between the detector and an operator of the detector or other computer device.

The memory162of the detector can comprise one or more computer readable storage media that may further comprise read only memory (ROM), random access memory (RAM), magnetic disk storage media devices, optical storage media devices, flash memory devices, electrical, optical and/or other physical/tangible (e.g., non-transitory) memory storage devices, and any combinations thereof. In other words, the one or more computer readable storage media are one or more physical, tangible hardware devices that that can retain and store instructions for use by the detector, for example including software comprising computer executable instructions operable to perform certain operations when the software is executed. A computer readable storage medium (or one or more computer readable storage media), as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire.

The scrubber or filter120for the system100is configured to selectively remove HF from a sample passing through the filter while allowing other chemical components, including most or substantially all other fluoride species, to remain in the sample for analysis by the detector105. Any suitable filter material that is capable of selectively scrubbing or removing HF from a gas sample with little or no removal of other fluoride and/or other components may be suitable for certain applications.

In example embodiments, the filter material comprises a silica-based scrubber substrate in the form of fibrous material or a material comprising an entangled mixture or bundle of silica fibers (e.g., silica wool) with a suitably large number of active sites that react selectively and irreversibly with acidic functional groups. In a non-limiting example, the scrubber substrate material comprises glass wool fibers having dimensions of no greater than about 4 cm in length and transverse cross sections (e.g., diameters) ranging from about 15 micrometers (microns) to about 25 microns. The bulk density of the material can range from about 20 kg/m3to about 160 kg/m3. The material can be pretreated by heating to a suitable temperature before use (e.g., about 80° C. for a period of about 6 hours). This scrubber substrate material has been found to meet certain criteria for effectively filtering of HF: effectively removes HF removal at high flow rates, high transmission rates allowed for other fluoride compounds, scrubber substrate is effective for a long period of time (long lifetime), it is easy to handle and manufacture, it has a low pressure drop and a large surface area to volume ratio (high sample gas to surface interaction to reduce filter volume to increase response time). However, as previously noted, any other suitable material (e.g., silica beads and/or any other form of filtration material) capable of effectively trapping and removing HF from a sample can be used in the systems and methods described herein.

The scrubber substrate can effectively remove up to 50 ppbv HF with an efficiency of greater than 99%. In addition, twelve fluorine-containing compounds, which cover four main compound classes (polyfluorinated hydrocarbons, perfluorocarbons, perfluoroalkylamines, and inorganic fluorides) and cover a range of chemical properties (boiling points, molecular weights, and polarities), can be present in a gas stream and further substantially remain in the gas stream after having been processed by the scrubber substrate. These types of fluorine-containing compounds can be present along with HF, e.g., in gases sampled from clean rooms and/or other processing locations within a semiconductor manufacturing or fabrication facility.

In an example embodiment, a scrubber substrate comprising silica wool was tested, with results shown in Table 1 below. Eleven of these fluorine-containing compounds were found to have transmission rates of greater than 99% when passed through the scrubber substrate (e.g., less than 1% by weight of fluorine-containing compound is trapped by and prevented from passing through the scrubber substrate), indicating a very low interference when determining presence and quantitation of HF according to the methods described herein. The only fluorine-containing compound that provided some level of interference was HFBA (heptafluorbutyric acid). However, this compound can still be compensated for and addressed based upon awareness of the potential issue it presents when utilizing the methods described herein. For example, HFBA, when present, can be accounted for by subtraction with a selective product ion so as to substantially prevent interference HF detection and quantitation.

The scrubber substrate can also be configured (e.g., by selection of suitable packing and particle or fiber sizes of the materials forming the substrate) such that the flow rate of sample is not significantly impacted when the sample is directed for flow through the filter. In an example in which a flow rate of unfiltered sample through the detector is set (e.g., by suitable control of pump and back pressure regulator parameters) at about 2 L/minute, the scrubber substrate can be configured such that the flow rate of the filtered sample is no more than 600 mL/minute less than the flow rate of the unfiltered sample. The effect of the flow rate can be diminished to a greater extent when utilizing shorter substrate (e.g., glass) fibers, such as fibers no greater than about 4 cm (e.g., 3 cm or less).

Thus, the scrubber substrate, when implemented by the system100by diverting sample flow via tee110, allows for selective removal of HF (and primarily or substantially only HF) from the sample without significantly impacting sample flow to the detector during system operations.

An example method of operation of the system100is described with reference toFIGS.2and3. Referring toFIG.2, a gas sample is collected (at210) from an environment (e.g., a cleaning room of a semiconductor manufacturing or fabrication facility) and utilizing the system100ofFIG.1. Such gas sample collection can occur continuously and at a selected flow rate. A suitable inert carrier gas (e.g., substantially pure nitrogen) can be used to transport the gas sample to the mass spectrometry (MS) detector105for analysis. An OH−reagent ion can be generated by source170and provided to the reaction chamber of the detector105to facilitate reaction with one or more compounds in the sample gas and determine concentration of analyte species containing fluorine. However, it is noted that any other one or more suitable reagent ions can also be utilized to obtain analyte fluorine species for analysis according to the methods described herein and utilizing standard or conventional SIFT-MS techniques. The unfiltered gas sample is analyzed by the detector105(at220), where signal data is collected (based upon the m/z ratios of ionized analyte species of the gas sample within the detector) and such data is analyzed to obtain an indication of total fluorine species concentration within the sample, which might be considered an apparent HF concentration in the sample. In other words, in this operation this gas sample has not been scrubbed prior to MS analysis.

At some point during operation, the gas sample is diverted through the HF scrubber/filter120(at230), and the filtered gas sample is then transported to the detector105for reaction with OH−(and/or other) reagent ion(s) and subjected to MS analysis (at240). The data from this analysis represents the sample having been filtered with certain fluorine species (primarily HF). Comparison of the sample with total fluorine species concentration (apparent HF concentration/unfiltered gas sample) and the filtered fluorine species concentration (filtered gas sample) is then performed (at250) to determine whether HF is present in the sample and, if so, to what extent (i.e., concentration of HF within the sampled gas).

The operational steps can all be automated and selectively controlled by the processor160of the detector105. Alternatively, or in combination with automated control, an operator can also manually direct performance of such operations via instructions provided to the controller of the detector105. In addition, it is noted that the sequential order of analyzing the gas sample with total fluorine species concentration (at220) and with filtered F−concentration (at240) is not important. In other words, data collection and MS analysis associated with the filtered gas sample can be obtained prior to data collection and MS analysis of the unfiltered gas sample (i.e., the sequential order of such data collection and analysis can be reversed).

The comparison of the signal data to determine HF concentration is depicted in the m/z data signal plots ofFIG.3. In particular,FIG.3shows a comparison of data signal plot310and data signal plot320, both obtained by the detector, where data signal plot310represents the unfiltered gas sample and data signal plot320represents the filtered gas sample. The data signal plot330represents the Filtered F−concentration of the filtered gas, where the data for plot330is obtained from a subtraction of filtered gas data signal plot320from unfiltered gas data signal plot310. To state in another manner, a determination of HF concentration in the sample can be reported by the detector based upon the following analysis of signals (S):

It has been determined that such analysis effectively removes the potential for interferents to provide an accurate determination of presence and quantification of HF in a gas sample by the MS system. Further, the methods described herein can also be used in combination with other techniques, such as subtraction of a signal for an independently measured compound that is a known interferent in a particular sample.

The following example demonstrates the effectiveness of the selective HF scrubber (SHFS) MS system and corresponding method as described herein for accurately determining presence and concentration of HF in a particular environment.

Example—Detection of HF from Gas Containing Nitrogen Trifluoride as an Interferent

Semiconductor fabrication utilizes a collection of processes such as deposition, removal, patterning, and modification, and such fabrication steps utilize a broad range of chemicals. To evaluate the performance of the selective HF scrubber (SHFS) system100and corresponding methods as described herein, a fab sample matrix was prepared that closely resembles an actual semiconductor fabrication environment.

Three commonly found HF-interfering fab airborne molecular contaminants (AMC) are octafluorocyclobutane (OFB) (used as an etchant and deposition gas), nitrogen trifluoride (NF3) (used to periodically clean reaction chambers), and perfluorotributylamine (PFTBA) (used as a refrigerant).

A range of process leaks were mimicked by delivering known concentrations (500 ppbv, 250 ppbv, 100 ppbv, 50 ppbv, 25 ppbv, 10 ppbv and 5 ppbv) of these three interferent gases with a constant 5 ppbv of HF. Reported concentrations of HF in the presence of these interferent compounds by system100without using the selective hydrogen fluoride scrubber (SHFS)/no HF scrubbing and using the SHFS/with HF scrubbing analysis are plotted inFIGS.4and5, respectively. Without using the SHFS process (FIG.4data), it is clear that the instrument response is significantly affected by the presence of interferences. The rate of false positives is large as the sample contains high loads of interferent gases. However, when the SHFS process is used (FIG.5data) according to methods as described herein (and depicted in the flowchart ofFIG.2), there is a significant reduction in the rate of false positives resulting in a significantly greater accuracy in detection and quantification of HF present in the gas. In other words, the response with the SHFS (shown inFIG.5) more accurately represents the actual HF concentration of 5 ppbv.

The following Table 3 details the results obtained for one of the interfering compounds (NF3). It is noted that the results are similar for the other two interferents.

Thus, the present invention facilitates accurate and reliable detection of HF as well as its quantitation in samples taken from environments in which such detection is particularly important as well as when other interfering fluorine-containing species may be present.

In an example embodiment, a mass spectrometry (MS) detection system with hydrogen fluoride (HF) specificity can comprise a MS detector to analyze a gas sample and determine a presence and/or a concentration of a plurality of chemical species within the gas sample, at least one sample flow line to facilitate flow of the gas sample from a sample source at a selected environment to an inlet of the MS detector, and a selective hydrogen fluoride scrubber coupled with the sample flow line, wherein the scrubber filters hydrogen fluoride (HF) from the gas sample prior to delivery to the inlet of the MS detector. The system can be configured to selectively permit a switch between a first flow of unfiltered gas sample to the inlet of the MS detector and a second flow of HF filtered gas sample to the inlet of the MS detector.

The scrubber can comprise a mixture of silica fibers having dimensions of no greater than 4 cm in length and transverse cross sections ranging from 15 micrometers to 25 micrometers.

The system can further comprise a diverter to selectively divert the gas sample in the sample flow line from the sample source between the first flow that bypasses the scrubber and the second flow that directs the gas sample through the scrubber.

In addition, the system can further comprise a controller that selectively controls flow of the gas sample from the sample source to the MS detector so as to facilitate delivery and analysis of the gas sample to the MS inlet in an unfiltered state via the first flow and delivery and analysis of the gas sample to the MS inlet in a HF filtered state via the second flow. The controller can further facilitate a determination of HF presence and/or HF concentration within the gas sample based upon a comparison of MS analysis of the sample gas in the unfiltered state and MS analysis of the sample gas in the HF filtered state.

The system can further comprise a reagent ion source that provides one or more reagent ions within the MS detector for exposure and reaction with one or more chemical compounds within the gas sample prior to determination of presence and/or concentration of chemical species within the MS detector. The reagent ion source can be operable to provide OH−ions within the MS detector for exposure and reaction with HF present within the gas sample. In addition, the MS detector can be operable to perform Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS) by exposure and reaction of a plurality of reagent ions with one or more chemical compounds within the gas sample.

In other example embodiments, a semiconductor fabrication facility can comprise a processing room that facilitates fabrication of a semiconductor component and includes the presence of hydrogen fluoride (HF), and the system as previously described herein, where the sample flow line communicates with and receives the gas sample from the processing room.

In further example embodiments, a mass spectrometry (MS) detection system with hydrogen fluoride (HF) specificity can comprise a MS detector to analyze a gas sample and determine a presence and/or a concentration of chemical species within the gas sample, a sample flow line that provides the gas sample from a selected environment to the MS detector, the sample flow line including a diverter to selectively divert the gas sample between a first sample line and a second sample line, where each of the first and second sample lines provide the gas sample to a MS inlet of the MS detector, a selective hydrogen fluoride scrubber (SHFS) provided in the second sample line, where the SHFS filters hydrogen fluoride (HF) from the gas sample prior to delivery to the inlet of the MS detector, and a controller that selectively controls the MS detector so as to facilitate delivery and analysis of the gas sample to the MS inlet in an unfiltered state via the first sample line and delivery and analysis of the gas sample to the MS inlet in a HF filtered state via the second sample line, where the controller further facilitates a determination of HF presence and/or HF concentration within the gas sample based upon a comparison of MS analysis of the sample gas in the unfiltered state and MS analysis of the sample gas in the HF filtered state.

In other example embodiments, a method for detection of hydrogen fluoride (HF) within a gas sample can comprise performing mass spectrometry (MS) analysis via a MS detector on a gas sample to obtain an unfiltered set of MS signal data, removing hydrogen fluoride (HF) from the gas sample by filtration to form a HF filtered gas sample, performing mass spectrometry (MS) analysis on the HF filtered gas sample to obtain a filtered set of MS signal data, comparing the filtered set of MS signal data with the unfiltered set of MS signal data, and determining a presence and/or a concentration of HF within the gas sample based upon the comparison.

The method can further comprise, prior to performing mass spectrometry (MS) analysis on the HF filtered gas sample, exposing and reacting one or more reagent ions with one or more chemical compounds within the gas sample to form one or more ionization products. In addition, the method can comprise generating the one or more reagent ions from a gas supply comprising oxygen, water and nitrogen. The one or more reagent ions can comprise OH−ions that react with HF within the gas sample.

In the method, the MS detector can comprise a processor, and the comparing the filtered set of MS signal data with the unfiltered set of MS signal data and determining the presence and/or concentration of HF within the gas sample based upon the comparison can be performed by the processor. The method can further comprise selectively diverting, via the processor, the gas sample prior to MS analysis between a first flow line and a second flow line, where the second flow line directs the gas sample through a selective hydrogen fluoride scrubber (SHFS) prior to being directed to an inlet of the MS detector, the SHFS removes hydrogen fluoride (HF) from the gas sample by filtration, and the first flow line directs the gas sample to the inlet of the MS detector while bypassing the SHFS.

The SHFS can comprise a mixture of silica fibers having dimensions of no greater than 4 cm in length and transverse cross sections ranging from 15 micrometers to 25 micrometers.

The method can further comprise receiving the gas sample from a processing room that facilitates fabrication of a semiconductor component.