Reaction cells for species detection

Abstract

The embodiments disclosed in this specification include semiconductor processing tools. In one embodiment, the semiconductor processing tool comprises a plasma source and a chamber connected to the plasma source. In one embodiment, a pump is connected to the chamber. In one embodiment, the semiconductor processing tool further comprises a sample line. In one embodiment, the sampling line includes a reaction chamber and an absorption chamber.

Description

Cross-reference of related applications

[0001] This application claims priority to U.S. Patent Application No. 17 / 841,557, filed on 15 June 2022, the entirety of which is incorporated herein by reference. [Technical Field]

[0002] The embodiments relate to the semiconductor manufacturing field, and more particularly to a laser absorption species sensor for controlling a plasma source. [Background technology]

[0003] Plasma processing tools, such as plasma deposition chambers and plasma etching chambers, sometimes rely on the generation of radical species to process substrates within the tool. Currently, the concentration of radical species generated in the chamber is unknown. In addition, plasma sources are prone to drift in performance over time. This can lead to significant differences in results on the substrate. Substrate performance is monitored daily with dummy substrates, and plasma source parameters are adjusted in uncertain ways to compensate for chamber drift. Entire batches of substrates may be lost until the processing tool parameters are properly adjusted.

[0004] Currently, no plasma sources on the market employ closed-loop plasma control. This is largely due to the lack of diagnostic tools to monitor radical generation. Instead, most tools rely on historical data to adjust their performance. This process is a trial-and-error approach to process control. This trial-and-error approach currently in use can result in a full day of faulty substrates on the tool. Furthermore, changes made based on monitored substrates using historical data do not guarantee satisfactory performance the following day. Thus, existing plasma processing tools are currently experiencing a significant impact on yield. [Overview of the project]

[0005] The embodiments disclosed herein include semiconductor processing tools. In one embodiment, the semiconductor processing tool includes a plasma source and a chamber connected to the plasma source. In one embodiment, a pump is connected to the chamber. In one embodiment, the semiconductor processing tool further includes a sample line. In one embodiment, the sampling line includes a reaction chamber and an absorption chamber.

[0006] The embodiments disclosed herein further include a method for determining radical concentration. In one embodiment, the method includes generating radicals using a plasma source, flowing a sample of the radicals through a sampling line, reacting the radicals with a first species to form a second species, and measuring the second species within an absorption chamber, wherein the measurement of the second species corresponds to the measurement of the radicals.

[0007] Embodiments may also include a semiconductor processing tool comprising a plasma source and a chamber fluidly connected to the plasma source. In one embodiment, a pump is fluidly connected to the chamber and a sampling line is in fluid parallel with the chamber. In one embodiment, the sampling line includes a reaction chamber and an absorption chamber.

Brief Description of the Drawings

[0008] [Figure 1A] FIG. Cross-sectional view of a plasma processing tool with a remote plasma source (RPS) provided on a pipe between the RPS and the main processing chamber. [Figure 1B] FIG. Cross-sectional view of a plasma processing tool with an RPS provided on a pipe between the RPS and the main processing chamber, wherein the laser light source and the detector are closer to the main processing chamber than the RPS. [Figure 1C]A cross-sectional view of a plasma processing tool with RPS according to an embodiment, including a laser light source and a detector provided on a main processing chamber above a substrate. [Figure 2] A cross-sectional view of a plasma processing tool according to an embodiment, including a laser light source and a detector on a main processing chamber above a substrate. [Figure 3A] A graph of laser absorption for a plurality of gas flow rates according to an embodiment. [Figure 3B] A graph of the concentration of a species versus gas flow rate according to an embodiment. [Figure 4A] A graph of laser absorption for a plurality of plasma power values according to an embodiment. [Figure 4B] A graph of the concentration of a species versus supplied power according to an embodiment. [Figure 5] A cross-sectional view of a plasma processing tool according to an embodiment, including a laser and a detector, wherein the detector is connected to a plasma controller to provide closed-loop control of the plasma within the chamber. [Figure 6] A process flow diagram of a process for controlling plasma within a plasma processing tool using closed-loop control notified by laser absorption spectroscopy according to an embodiment. [Figure 7A] A schematic diagram of a plasma processing tool including a radical concentration measurement line according to an embodiment. [Figure 7B] A schematic diagram of a plasma processing tool including a radical concentration measurement line according to a further embodiment. [Figure 7C] A schematic diagram of a plasma processing tool including a radical concentration measurement line according to a further embodiment. [Figure 8A] A cross-sectional view of a reaction chamber on a radical concentration measurement line according to an embodiment. [Figure 8B] A view of a measurement chamber on a radical concentration measurement line according to an embodiment. [Figure 9]This is a diagram illustrating a combination of a reaction channel and a measurement chamber on a radical concentration measurement line according to one embodiment. [Figure 10] This is a process flow diagram of a process for measuring the flux of radicals in a semiconductor processing chamber according to one embodiment. [Figure 11A] A graph showing the voltage division of HF against power and the corresponding etching rate according to one embodiment is shown. [Figure 11B] A graph of the partial voltage of HF against the etching rate according to one embodiment is shown. [Figure 12] A block diagram of an exemplary computer system that can be used with a processing tool according to one embodiment is shown. [Modes for carrying out the invention]

[0009] The system described herein includes a laser absorption species sensor for controlling a plasma source. The following description includes numerous specific details to provide a comprehensive understanding of the embodiments. Those skilled in the art will see that the embodiments can be carried out without these specific details. In other cases, well-known embodiments are not described in detail to avoid unnecessarily obscuring the embodiments. Furthermore, it should be understood that the various embodiments shown in the accompanying figures are illustrative and not necessarily drawn to scale.

[0010] As mentioned earlier, there is currently no closed-loop control system within the plasma processing tool. Instead, a dummy substrate is driven periodically, and changes are made to the plasma processing tool based on past data obtained during dummy substrate processing. Because chamber control is instructed based on past data, it is difficult to properly match the process in the plasma processing tool. This can lead to significant yield losses. In addition, once the plasma processing tool is properly matched, chamber drift can cause the process to deviate from specifications, and it may be necessary to drive other dummy substrates to recalibrate the tool. The inability to constantly monitor tool performance can also lead to chamber matching problems between various chambers.

[0011] Accordingly, embodiments disclosed herein include plasma processing tools that enable closed-loop control. Closed-loop control may be provided using laser absorption spectroscopy. Laser absorption spectroscopy involves propagating a laser through the internal space of a chamber. Seeds in the chamber absorb a portion of the laser intensity. Therefore, by measuring the absorption of the laser using a detector, it becomes possible to quantitatively measure the concentration of seeds in the chamber. The measured seed concentration can be fed back to a plasma controller to modify one or more process parameters and ultimately return the seed concentration to a desired value. For example, one or more of the following may be changed to adjust the seed concentration: gas flow rate, power supplied to the plasma, plasma frequency, pressure in the processing chamber, and temperature of the processing chamber.

[0012] In one embodiment, laser absorption spectroscopy may be performed within a remote plasma source (RPS) tool. In such an embodiment, the laser source and detector may be located along a pipe between the remote plasma chamber and the processing chamber. In another embodiment, the laser source and detector may be located within the main processing chamber. For example, the laser source and detector may be located within 10 mm of the substrate. By moving the laser source and detector closer to the substrate, the measurement of the concentration of species that directly interact with the substrate may become more accurate. In another embodiment, a standard plasma processing tool may be used. That is, the plasma source can directly induce plasma in the main processing chamber above the substrate.

[0013] It should be understood that not all types of radicals or species are suitable for laser absorption spectroscopy. In such cases, a measurement line may be provided in fluid parallel to the main processing chamber. The measurement line may include a first chamber, which is a reaction chamber. Within the reaction chamber, radicals (or species) are introduced into the chamber and react with a first gas. The first gas reacts with the radicals to form a second gas. The second gas may contain species that can be measured using laser absorption spectroscopy. The second gas then flows into a second chamber, which is a measurement chamber. The second chamber may include a window to allow a laser to pass through the chamber in order to determine the absorption of the second gas. The absorption of the second gas can be directly correlated with the concentration (or flux) of the radical species.

[0014] Referring here to Figure 1A, a cross-sectional view of a semiconductor processing tool 100 according to one embodiment is shown. The semiconductor processing tool 100 may include any type of plasma processing tool. For example, the semiconductor processing tool 100 may be a plasma etching chamber or a plasma deposition chamber. The semiconductor processing tool 100 may be a standalone tool, or it may be part of a cluster tool. That is, multiple repetitions of the semiconductor processing tool 100 (or various processing tools) may be mechanically connected by a central hub chamber.

[0015] In the illustrated embodiment, the semiconductor processing tool 100 is shown as an RPS tool. The RPS semiconductor processing tool 100 may include a plasma chamber 130, a pipe 120, and a main processing chamber 110. The pipe 120 can fluidly connect the plasma chamber 130 and the main processing chamber 110. In the illustrated embodiment, the plasma chamber 130 is located above the main processing chamber 110. However, embodiments are not limited to this configuration, and the plasma chamber 130 can be located at any position around the main processing chamber 110. As shown, the plasma 115 is substantially contained within the plasma chamber 130.

[0016] For simplicity, the plasma chamber 130 is shown as an unremarkable chamber. However, it should be understood that the plasma chamber 130 may include a lid or showerhead through which gas flows into the chamber. The lid may also function as an RF source or microwave source for generating plasma within the plasma chamber 130. In one embodiment, the volume of the plasma chamber 130 is smaller than the volume of the main processing chamber 110.

[0017] In one embodiment, the main processing chamber 110 may include a pedestal 105. In one embodiment, the pedestal 105 may include a chuck structure. For example, the pedestal 105 may include an electrostatic chuck (ESC). The pedestal 105 may also include a thermal control (e.g., heating or cooling) structure to control the temperature of the substrate 107 fixed by the pedestal 105. In one embodiment, the substrate 107 may be any substrate suitable for a semiconductor processing process. For example, the substrate 107 may be a semiconductor wafer such as a silicon wafer. The substrate 107 may also include glass, ceramic, or organic material. In one embodiment, the substrate 107 may have any form factor. For example, the substrate 107 may be a 300 mm wafer or a 450 mm wafer, etc. An exhaust device (not shown) may also be provided in the main processing chamber 110.

[0018] In one embodiment, the laser absorption spectroscopy tool may include a laser light source 141 and a detector 142. The laser light source 141 may be connected above a first window 143 penetrating the side wall of the pipe 120, and the detector 142 may be connected above a second window 144 penetrating the side wall of the pipe 120. In one embodiment, the laser light source 141 and the detector 142 may be located closer to the plasma chamber 130 than to the main processing chamber 110.

[0019] In one embodiment, a laser 145 propagating from a laser light source 141 passes through the space of a pipe 120 and is optically coupled to a detector 142. In one embodiment, the laser light source 141 may be a laser of any suitable wavelength suitable for laser absorption spectroscopy. For example, according to one embodiment, a 1278 nm laser light source 141 may be used. The detector 142 may be any type of optical detector. For example, the detector 142 may be a charge-coupled device (CCD).

[0020] Referring now to Figure 1B, a cross-sectional view of a semiconductor processing tool 100 according to one embodiment is shown. The semiconductor processing tool 100 may include any type of plasma processing tool. For example, the semiconductor processing tool 100 may be a plasma etching chamber or a plasma deposition chamber. The semiconductor processing tool 100 may be a standalone tool, or it may be part of a cluster tool.

[0021] In the illustrated embodiment, the semiconductor processing tool 100 is shown as an RPS tool. The RPS semiconductor processing tool 100 may include a plasma chamber 130, a pipe 120, and a main processing chamber 110. The pipe 120 can fluidly connect the plasma chamber 130 and the main processing chamber 110.

[0022] For simplicity, the plasma chamber 130 is shown as an unremarkable chamber. However, it should be understood that the plasma chamber 130 may include a lid or showerhead through which gas flows into the chamber. The lid may also function as an RF source or microwave source for generating plasma within the plasma chamber 130. In one embodiment, the volume of the plasma chamber 130 is smaller than the volume of the main processing chamber 110.

[0023] In one embodiment, the main processing chamber 110 may include a pedestal 105. In one embodiment, the pedestal 105 may include a chuck structure such as an ESC structure. The pedestal 105 may also include a thermal control (e.g., heating or cooling) structure to control the temperature of the substrate 107 fixed by the pedestal 105. In one embodiment, the substrate 107 may be any substrate suitable for a semiconductor processing process. For example, the substrate 107 may be a semiconductor wafer such as a silicon wafer, but other substrate materials may also be used. An exhaust system (not shown) may also be provided within the main processing chamber 110.

[0024] In one embodiment, the laser absorption spectroscopy tool may include a laser light source 141 and a detector 142. The laser light source 141 may be connected above a first window 143 penetrating the side wall of the pipe 120, and the detector 142 may be connected above a second window 144 penetrating the side wall of the pipe 120. In one embodiment, the laser light source 141 and the detector 142 may be located closer to the main processing chamber 110 than to the plasma chamber 130. In such embodiments, the concentration of species being measured may consequently be close to the concentration of species interacting with the substrate 107.

[0025] In one embodiment, a laser 145 propagating from a laser light source 141 passes through the space of a pipe 120 and is optically coupled to a detector 142. In one embodiment, the laser light source 141 may be a laser of any suitable wavelength suitable for laser absorption spectroscopy. For example, according to one embodiment, a 1278 nm laser light source 141 may be used. The detector 142 may be any type of optical detector. For example, the detector 142 may be a CCD.

[0026] Referring now to Figure 1C, a cross-sectional view of a semiconductor processing tool 100 according to one embodiment is shown. The semiconductor processing tool 100 may include any type of plasma processing tool. For example, the semiconductor processing tool 100 may be a plasma etching chamber or a plasma deposition chamber. The semiconductor processing tool 100 may be a standalone tool, or it may be part of a cluster tool.

[0027] In the illustrated embodiment, the semiconductor processing tool 100 is shown as an RPS tool. The RPS semiconductor processing tool 100 may include a plasma chamber 130, a pipe 120, and a main processing chamber 110. The pipe 120 can fluidly connect the plasma chamber 130 and the main processing chamber 110.

[0028] For simplicity, the plasma chamber 130 is shown as an unremarkable chamber. However, it should be understood that the plasma chamber 130 may include a lid or showerhead through which gas flows into the chamber. The lid may also function as an RF source or microwave source for generating plasma within the plasma chamber 130. In one embodiment, the volume of the plasma chamber 130 is smaller than the volume of the main processing chamber 110.

[0029] In one embodiment, the main processing chamber 110 may include a pedestal 105. In one embodiment, the pedestal 105 may include a chuck structure such as an ESC structure. The pedestal 105 may also include a thermal control (e.g., heating or cooling) structure to control the temperature of the substrate 107 fixed by the pedestal 105. In one embodiment, the substrate 107 may be any substrate suitable for a semiconductor processing process. For example, the substrate 107 may be a semiconductor wafer such as a silicon wafer, but other substrate materials may also be used. An exhaust system (not shown) may also be provided within the main processing chamber 110.

[0030] In one embodiment, the laser absorption spectroscopy tool may include a laser light source 141 and a detector 142. The laser light source 141 may be connected above a first window 143 penetrating the side wall of the main processing chamber 110, and the detector 142 may be connected above a second window 144 penetrating the side wall of the main processing chamber 110. In one embodiment, the laser light source 141 and the detector 142 may be located relatively close to the substrate 107. For example, the laser 145 may be located about 10 mm or less away from the substrate 107. In a particular embodiment, the laser 145 may be located about 5 mm or less away from the substrate 107. In such embodiments, the measured species concentration may consequently be close to the concentration of species that actually interact with the substrate 107.

[0031] In one embodiment, a laser 145 propagated by a laser light source 141 passes through the space of the main processing chamber 110 and is optically coupled to a detector 142. In one embodiment, the laser light source 141 may be a laser of any suitable wavelength suitable for laser absorption spectroscopy. For example, according to one embodiment, a 1278 nm laser light source 141 may be used. The detector 142 may be any type of optical detector. For example, the detector 142 may be a CCD device.

[0032] Referring now to Figure 2, a cross-sectional view of a semiconductor processing tool 200 according to one embodiment is shown. In one embodiment, the semiconductor processing tool 200 can be any plasma chamber, such as a plasma etching chamber or a plasma deposition chamber. In contrast to the RPS embodiment described above, the semiconductor processing tool 200 can be a standard plasma tool according to one embodiment. That is, the plasma 215 is generated in the same space as the substrate 207.

[0033] Plasma 215 can be generated using an RF source or microwave source connected to the lid 211 of the chamber 210. The lid 211 may include a conductive feature that couples microwave or RF signals to the processing gas in the chamber 210 to generate plasma 215. In one embodiment, the lid 211 may be a gas showerhead, that is, a gas (e.g., processing gas, inert gas, etc.) may flow into the chamber 210 through the lid 211. The gas flow path through the lid 211 is omitted for simplicity. In addition, in some embodiments, the gas may flow into the chamber 210 through surfaces other than the lid 211.

[0034] In one embodiment, the pedestal 205 may be provided within the chamber 205. In one embodiment, the pedestal 205 may include a chuck structure such as an ESC structure. The pedestal 205 may also include a thermal control (e.g., heating or cooling) structure to control the temperature of the substrate 207 to which the pedestal 205 is fixed. In one embodiment, the substrate 207 may be any substrate suitable for a semiconductor processing process. For example, the substrate 207 may be a semiconductor wafer such as a silicon wafer, but other substrate materials may also be used. An exhaust system (not shown) may also be provided within the processing chamber 210.

[0035] In one embodiment, the laser absorption spectroscopy tool may include a laser light source 241 and a detector 242. The laser light source 241 may be connected above a first window 243 penetrating the side wall of the processing chamber 210, and the detector 242 may be connected above a second window 244 penetrating the side wall of the processing chamber 210. In one embodiment, the laser light source 241 and the detector 242 may be located relatively close to the substrate 207. For example, the laser 245 may be located about 10 mm or less away from the substrate 207. In a particular embodiment, the laser 245 may be located about 5 mm or less away from the substrate 207. In such embodiments, the measured species concentration may consequently be close to the concentration of species that actually interact with the substrate 207.

[0036] In one embodiment, a laser 245 propagated by a laser light source 241 passes through the space of the processing chamber 210 and is optically coupled to a detector 242. In one embodiment, the laser light source 241 may be a laser of any suitable wavelength suitable for laser absorption spectroscopy. For example, according to one embodiment, a 1278 nm laser light source 241 may be used. The detector 242 may be any type of optical detector. For example, the detector 242 may be a CCD.

[0037] Referring now to Figure 3A, a graph of laser absorption-wavelength according to one embodiment is shown. The graph shows several different gas flow rates. In one embodiment, the measured gas flow rates may be for one or more gases flowing into the chamber. For example, the processing gas may contain NF3. In one embodiment, the gas flow rates may range from 40 sccm to 150 sccm, but lower or higher gas flow rates may also be used. As shown, higher gas flow rates correspond to higher absorptivity. Referring now to Figure 3B, a graph of species concentration against gas flow rate according to one embodiment is shown. In the specific case of NF3 gas, the partial pressure may be that of HF species. As shown, higher gas flow rates correspond to higher species concentrations. By combining the graphs of Figure 3A and Figure 3B, it is possible to calculate the species concentration in a given process using laser absorptivity.

[0038] Referring now to Figure 4A, a graph of laser absorption-wavelength according to one embodiment is shown. The graph shows several different power supply levels. In one embodiment, power supply may refer to the power supplied to the plasma in the chamber. In one embodiment, the supplied power may range from 310W to 415W, but lower and higher power may also be used. As shown, higher supplied power corresponds to higher absorptivity. Referring now to Figure 4B, a graph of species concentration (i.e., partial pressure) against supplied power according to one embodiment is shown. As shown, higher supplied power corresponds to higher species concentration. By combining the graphs in Figure 4A and Figure 4B, it is possible to calculate the species concentration in a given process using the laser absorptivity.

[0039] Figures 3A to 4B use examples of gas flow rate and power supply to illustrate how laser absorption spectroscopy can be used to determine species concentrations. However, it should be understood that other plasma parameters can also be used to change the species concentrations measured by the laser absorption spectroscopy tool. For example, plasma frequency, pressure in the processing chamber, and temperature in the processing chamber can also be changed to alter the species concentration in the chamber. Furthermore, while an example of HF is provided as a measured species concentration, it should be understood that other species or combinations of species can also be monitored. For example, the concentrations of one or more of the following can be monitored by laser absorption spectroscopy: HF, O, Ar, N, NH, NH2, NH3, F, He, H, H2, F2, NF, NF2, NF3, Cl, HCl, CH, CH2, CH3, CH4, C2H2, C, H2O, OH, H2S, HS, PH, PH2, PH3, P, SiH, SiH2, SiH3, SiH4, and Si.

[0040] Referring now to Figure 5, a cross-sectional view of a semiconductor processing tool 500 according to one embodiment is shown. In one embodiment, the semiconductor processing tool 500 may be substantially the same as the semiconductor processing tool 100 shown in Figure 1A. For example, a plasma chamber 530 may be fluidly connected to a main processing chamber 510 by a pipe 520. The main processing chamber 510 may include a pedestal 505 and a substrate 507 on the pedestal 505. In one embodiment, plasma 515 may be generated in the plasma chamber 530. Furthermore, a laser absorption spectroscopy tool including a laser light source 541 and a detector 542 may be included. The laser light source 541 and the detector 542 may be optically coupled to each other via windows 543 and 544 provided in the pipe 520. The laser 542 may pass between windows 543 and 544 from the laser light source 541 to the detector 542.

[0041] Figure 5 also includes a feedback loop 555. The feedback loop 555 can return to the plasma controller 550. The plasma controller 550 can be used to control one or more parameters of plasma generation within the plasma chamber 530. For example, the plasma controller 550 may control the gas flow rate, the power supplied to the plasma, the plasma frequency, the pressure within the plasma chamber 530, and the temperature of the plasma chamber 530. The feedback loop 555 can provide a closed-loop control solution for monitoring and controlling the concentration of species within the semiconductor processing tool. Thus, it may be possible to control processing conditions without relying on historical data and / or dummy substrates.

[0042] Referring now to Figure 6, a processing flow diagram of process 660 according to one embodiment is shown. In one embodiment, process 660 may be used to control the concentration of species in a semiconductor processing chamber.

[0043] In one embodiment, process 660 may be initiated by step 661, which includes generating plasma in a processing chamber. In one embodiment, the processing chamber may be any of the processing chambers described in more detail herein. For example, the processing chamber may be an RPS chamber or a standard plasma chamber.

[0044] In one embodiment, process 660 may be followed by step 662, which includes using a laser light source and propagating a laser through a chamber. The laser light source can be any suitable wavelength for laser absorption spectroscopy, and in some embodiments may even include multiple wavelengths. As the laser passes through the chamber, the laser interacts with the seeds and power is absorbed from the laser.

[0045] In one embodiment, process 660 may be followed by step 663, which includes detecting the laser using a detector after the laser has passed through the chamber. In one embodiment, the detector may be a CCD or other optical detection structure. In one embodiment, the detector may be on the opposite side from the laser source. Thus, the laser can propagate straight across the chamber from the laser source to the detector. The laser source and detector may be outside a window that penetrates the side wall of the chamber.

[0046] In one embodiment, process 660 may be followed by step 664, which includes detecting the absorption of the laser using a detector after the laser has passed through the chamber. In one embodiment, the amount of laser absorption can be correlated with the density of species in the chamber.

[0047] In one embodiment, process 660 may be followed by step 665, which includes controlling the plasma in the processing chamber in response to detected laser absorption. For example, feedback from laser absorption can be used to change one or more plasma variables, such as gas flow rate, power supplied to the plasma, plasma frequency, pressure in the processing chamber, and temperature of the processing chamber.

[0048] As described above, not all radical species or other species can be directly measured by laser absorption spectroscopy. In response to this, embodiments disclosed herein further include a measurement line capable of converting radicals (or species) into species measurable by the laser absorption spectroscopy process. In some embodiments, the measurement line is fluidically parallel to the main processing chamber. In other embodiments, the measurement line may be directly connected to the main processing chamber. In yet another embodiment, the measurement line is downstream of the main processing chamber. In one embodiment, the measurement line may include a reaction chamber and a measurement chamber. In other embodiments, the reaction chamber and the measurement chamber may be combined into a single structure.

[0049] Referring now to Figure 7A, a schematic diagram of a semiconductor processing tool 700 according to one embodiment is shown. In one embodiment, the semiconductor processing tool 700 may include a remote plasma source 730. Although an embodiment including a remote plasma source 730 is shown, it should be understood that any device capable of generating radicals can be used instead of the remote plasma source 730.

[0050] In one embodiment, a remote plasma source 730 may be fluidically connected to the main processing chamber 710. The main processing chamber 710 may include a chuck or the like for securing a substrate (not shown). The main processing chamber may be used as a deposition chamber, an etching chamber, or another chamber for semiconductor processing involving radical species.

[0051] In one embodiment, the main processing chamber 710 may be fluidly connected to a pump 713. The pump 713 provides a low-pressure environment (e.g., a vacuum environment) for the main processing chamber 710. As is common in semiconductor manufacturing tools, a chamber throttle valve 711 and a chamber shut-off valve 712 may be provided between the pump 713 and the chamber 710.

[0052] In one embodiment, pressure P U However, this can be provided between the remote plasma source 730 and the main chamber 710. Within the chamber 710, the chamber pressure P CH It can provide, and in pump 713, pump pressure TIFF0007884617000001.tif7170 can be provided. In one embodiment, pressure P U pressure P CH Larger, pressure P CH pressure It is greater than TIFF0007884617000002.tif7170.

[0053] In one embodiment, the measurement line can be provided fluidly in parallel with the chamber 710. That is, the inlet to the measurement line can be upstream of the chamber 710, and the outlet of the measurement line can be downstream of the chamber 710. For example, the inlet to the measurement line can be provided between the remote plasma source 730 and the chamber 730, and the outlet of the measurement line can be provided between the shut-off valve 712 and the pump 713.

[0054] In one embodiment, the measurement line is configured to modify radicals (or species) generated by the remote plasma source 730 such that the radicals (or species) are suitable for laser absorption spectroscopy. For example, it is possible to carry out a controlled chemical reaction with the radicals (or species) to generate new species that can be detected by laser absorption spectroscopy. In this case, the measurement of the new species can be used to calculate the concentration or flux of the original radicals (or species).

[0055] In one embodiment, the measurement line can include a reaction cell 731. The reaction cell 731 can be a chamber in which radicals are reacted to form new species. Thus, in some cases, the reaction cell 731 can be referred to as the reaction chamber 731. In one embodiment, the reaction cell 731 can receive radicals as a first input, and the reaction cell 731 can receive a first gas as a second input. The radicals and the first gas can react with each other to form a second gas. The second gas contains species that can be measured using laser absorption spectroscopy. A more detailed description of the reaction cell 731 is provided below.

[0056] In certain embodiments, the radical or species of interest can be fluorine. In such embodiments, the first gas is H2, C X H Y X Z (where X is F or Cl), C X H YIt may contain one or more of NH3, B2H6, and H2O. The reaction of F with the first gas can generate HF, which can be measured by laser absorption spectroscopy. In other embodiments, the radical or species of interest may be chlorine. In such embodiments, the first gas may be H2, C X H Y X Z (However, X is F or Cl), C X H Y It may contain one or more of NH3, B2H6, and H2O. The reaction of Cl with the first gas can generate HCl, which can be measured by laser absorption spectroscopy. In other embodiments, the radical or species of interest may be oxygen. In such embodiments, the first gas may be C X H Y It may contain one or more of H2, NH3, or B2H6. The reaction of O with the first gas can generate one or more of CO, CO2, and H2O, which can be measured by laser absorption spectroscopy. In yet another embodiment, the radical or species of interest may be hydrogen. In such an embodiment, the first gas may be NF3, C X F Y X Z (wherein X is F or Cl), Cl2, F2, SF6, SiH X F (4-X) SiH X Cl (4-X) GeH X F (4-X) , and GeH X Cl (4-X) It may contain one or more of the following. The reaction of H with the first gas can generate HF and HCl, which can be measured by laser absorption spectroscopy. The radical may also contain sulfur, phosphorus, or silicon. The reaction also generates NH, NH2, NH3, HS, H2S, PH, PH2, PH3, C, which can be measured by laser absorption spectroscopy. x H yIt is also possible to generate one or more of SiH, SiH2, SiH3, and SiH4. Although several examples of material classes are shown, it will be understood that any radical or species that can be reacted to form a new species measurable by laser absorption spectroscopy can be used according to the embodiments described herein.

[0057] In one embodiment, the measurement line may further include a measurement cell 732. The measurement cell 732 may be a chamber in which a second gas is measured using laser absorption spectroscopy. Thus, the measurement cell 732 may optionally be referred to as the measurement chamber 732 or absorption chamber 732. In one embodiment, the measurement cell 732 can receive a second gas as input. The second gas is then measured using laser absorption spectroscopy. For example, a pair of opposing windows may allow a laser to pass through the measurement cell 732 and be detected by a photodetector. A more detailed description of the measurement cell 732 is provided below.

[0058] In one embodiment, the measuring cell 732 is at pressure P A It may have pressure P A is pressure P U Smaller, pressure Greater than TIFF0007884617000003.tif7170. Pressure P A This is achieved by controlling the throttle valve 733 downstream of the measurement cell 732, P U and It may be controlled to be one of the values ​​between TIFF0007884617000004.tif7170. In an additional embodiment, a mass flow meter (MFM) 734 may be provided between the throttle valve 733 and the pump 713.

[0059] Referring now to Figure 7B, a schematic diagram of a semiconductor processing tool 700 according to one embodiment is shown. The semiconductor processing tool 700 in Figure 7B may be substantially the same as the semiconductor processing tool 700 in Figure 7A, except for the fluid connection of the measurement line. Instead of being fluidly parallel to the main processing chamber 710, the upstream side of the measurement line is connected to the chamber 710. Thus, the flux of radicals entering the chamber can be determined by the measurement line. In the illustrated embodiment, a remote plasma source 730 is shown. However, it should be understood that a plasma source integrated with the main processing chamber 710 can also be used. The measurement line may have a downstream end connected to a gas line between a shut-off valve 712 and a pump 713.

[0060] Referring now to Figure 7C, a schematic diagram of a semiconductor processing tool 700 according to one embodiment is shown. In one embodiment, the semiconductor processing tool 700 of Figure 7C may be substantially the same as the semiconductor processing tool 700 of Figure 7A, except for the fluid connection of the measurement line. Instead of being fluidly parallel to the main processing chamber 710, the upstream side of the measurement line is connected to the gas line between the main chamber 710 and the throttle valve 711. In this way, the flux of radicals leaving the chamber can be determined by the measurement line. In the illustrated embodiment, a remote plasma source 730 is shown. However, it should be understood that a plasma source integrated with the main processing chamber 710 can also be used. The measurement line may have a downstream end connected to the gas line between the shut-off valve 712 and the pump 713.

[0061] Figures 7A to 7C show three different measurement line structures. However, it should be understood that in some embodiments, the three different measurement line structures can be combined with each other. For example, two or more different measurement lines may be provided within a single semiconductor processing tool 700. That is, a single semiconductor processing tool 700 may include a first measurement line with an input between the plasma source and the main chamber, a second measurement line with an input in the main chamber, and a third measurement line with an input downstream of the main chamber.

[0062] Referring now to Figure 8A, a cross-sectional view of a reaction cell 831 that may be used in a semiconductor processing tool according to one embodiment is shown. In one embodiment, the reaction cell 831 may include a chamber 821. This chamber may be fluidically connected to the main processing line of the plasma processing tool. For example, the reaction cell 831 may be fluidically connected between a remote plasma source and the main chamber, fluidly connected to the main chamber, or fluidly connected downstream of the main chamber, as in the embodiments shown in Figures 7A to 7C.

[0063] In one embodiment, the chamber 821 may have a plurality of gas supply lines. Supply line 822 may be used to introduce radicals 827 into the chamber 821 from a remote plasma source (or another source of radicals or species). In one embodiment, a second supply line 823 is used to introduce the first gas 828 into the chamber 821. The flow rate of the first gas 828 may be controlled by a mass flow controller (not shown). In this way, a specific amount of the first gas 828 can flow into the chamber 821 and react with the species 827 to form the second gas 829. In one embodiment, a third supply line 824 may function as an outlet from the chamber 821. The second gas 829 can exit the chamber 821 through the third supply line 824. In one embodiment, the second gas 829 may contain the species to be measured. In an additional embodiment, the second gas 829 may contain other species that are part of the reaction between the radical and the first gas but are not to be measured.

[0064] In one embodiment, the chamber 821 may also include a thermometer 825 or any other device capable of measuring temperature. The thermometer 825 may be used to control the temperature of the chamber 821. For example, the chamber 821 may be heated or cooled to facilitate a particular reaction. In addition, the chamber 821 may include a transducer 826. The transducer 826 may be used in combination with a throttle valve (for example, the throttle valve 733 in Figure 7A) to control the pressure within the chamber 821.

[0065] Referring now to Figure 8B, a schematic diagram of a measuring cell 832 according to one embodiment is shown. In one embodiment, the measuring cell 832 may include a chamber 836. The chamber 836 may be fluidly connected to the chamber 821 via a third supply line 824. Thus, the second gas 829 flows into the chamber 836. The second gas 829 flows through the chamber 821 and exits as gas 835. In one embodiment, gas 835 may be substantially the same as the second gas 829, that is, no further reaction may occur in the chamber 836.

[0066] In one embodiment, the measurement cell 832 may further include a pair of windows 837 and 838. Windows 837 and 838 may be located on opposite sides of the chamber 836. A light source 841 (e.g., a laser) may be located near window 837, and a photodetector 842 may be located near window 838. The light source 841 is configured to emit light 845 that passes through windows 837 and 838, and the light source 841 is optically coupled to the photodetector 842. The light 845 is partially absorbed by the second gas 829. The amount of absorbed light 845 is detected by the photodetector 842 to determine the concentration of the measured species. The measured species concentration can then be used to calculate the concentration or flux of radical species flowing into the measurement line.

[0067] In one embodiment, the chamber 836 may also include a thermometer 825 or any other device capable of measuring temperature. The thermometer 825 may be used to control the temperature of the chamber 836. For example, the chamber 836 may be heated or cooled. In addition, the chamber 836 may include a transducer 826. The transducer 826 may be used in combination with a throttle valve (for example, the throttle valve 733 in Figure 7A) to control the pressure within the chamber 836.

[0068] Referring now to Figure 9, a diagram is shown of a combination of a reaction cell 931 and a measurement cell 932 according to one embodiment. That is, instead of having separate chambers (as shown in Figures 8A and 8B), cells 931 / 932 may comprise a single chamber 936. Thus, the chemical reaction (for converting radical species into measurable species) and the absorption measurement may be provided within the same chamber 936.

[0069] In one embodiment, radical species 927 may flow into the chamber 936. In one embodiment, the first gas 928 also flows into the chamber 936. The amount of the first gas 928 flowing into the chamber 936 may be controlled by a mass flow controller (not shown). The first gas 928 and the radical species 927 may react to form a second gas 935, which flows out of the chamber 936.

[0070] Furthermore, a laser absorption spectroscopy structure is provided on the chamber 936. For example, a pair of windows 937 and 938 may be located on opposite sides of the chamber 936. A light source 941 (e.g., a laser) can be provided near window 937, and a photodetector 942 can be provided near window 938. The light source 941 is configured to emit light 945 that passes through windows 937 and 938, and the light source 941 is optically coupled to the photodetector 942. The light 945 is partially absorbed by the second gas 935. The amount of absorbed light 945 is detected by the photodetector 942 to determine the concentration of the measured species. The measured species concentration can then be used to calculate the concentration or flux of radical species 927 that have flowed into the chamber 936.

[0071] In one embodiment, the chamber 936 may also include a thermometer 925 or any other device capable of measuring temperature. The thermometer 925 may be used to control the temperature of the chamber 936. For example, the chamber 936 may be heated or cooled to facilitate a particular reaction. In addition, the chamber 936 may include a transducer 926. The transducer 926 may be used in combination with a throttle valve (for example, the throttle valve 733 in Figure 7A) to control the pressure within the chamber 936.

[0072] Referring now to Figure 10, a process flow diagram of process 1080 for measuring radical flux within a semiconductor processing tool according to one embodiment is shown. In one embodiment, process 1080 may be performed using any of the above-described semiconductor processing tools, including a measurement line.

[0073] In one embodiment, process 1080 may begin with step 1081, which includes generating radicals using a plasma source. In some embodiments, radicals may be generated using a remote plasma source. However, other plasma sources may also be used, depending on the configuration of the semiconductor processing tool. Furthermore, it should be understood that other species may also be generated in step 1081, although they are referred to as radicals. In certain embodiments, the generated radicals (or species) are radicals (or species) that cannot be easily measured directly using laser absorption spectroscopy. That is, measuring radicals or species would require significant expenditure on equipment and engineering. For example, radicals may contain one or more of the following: fluorine, oxygen, chlorine, sulfur, phosphorus, silicon, and hydrogen.

[0074] In one embodiment, process 1080 may be followed by step 1082, which includes passing a sample of radicals through a sampling line. In one embodiment, the radicals may be passed through the sampling line before reaching the main processing chamber. In another embodiment, the radicals may be passed through the sampling line after reaching the main processing chamber. In yet another embodiment, the radicals may be passed through the sampling line after passing through the main processing chamber. In one embodiment, the downstream side of the sampling line may be connected to a line before the pump of the semiconductor processing tool. For example, the downstream side of the sampling line may be located between a shut-off valve and the pump.

[0075] In one embodiment, process 1080 may be followed by step 1083, which includes reacting a radical with a first species to form a second species. In certain embodiments, the radical or species of interest may be fluorine. In such embodiments, the first species may be H2, C X H Y X Z (However, X is F or Cl), C X H Y It may contain one or more of NH3, B2H6, and H2O. The reaction of F with the first species can generate a gas containing a second species, HF, which can be measured by laser absorption spectroscopy. In other embodiments, the radical or species of interest may be chlorine. In such embodiments, the first species may be H2, C X H Y X Z( However, X is F or Cl), C X H Y It may contain one or more of NH3, B2H6, and H2O. The reaction of Cl with the first species can generate a gas containing a second species, HCl, which can be measured by laser absorption spectroscopy. In other embodiments, the radical or species of interest may be oxygen. In such embodiments, the first species is C X H YIt may contain one or more of H2, NH3, or B2H6. The reaction of O with the first species can generate a gas containing a second species which contains one or more of CO, CO2, and H2O that can be measured by laser absorption spectroscopy. In yet another embodiment, the radical or species of interest may be hydrogen. In such an embodiment, the first species may be NF3, C X F Y X Z (wherein X is F or Cl), Cl2, F2, SF6, SiH X F (4-X) SiH X Cl (4-X) GeH X F (4-X) , and GeH X Cl (4-X) It may contain one or more of the following. The reaction of H with the first species can generate a gas containing a second species which contains one or more HF and HCl measurable by laser absorption spectroscopy. Although several examples of material classes are shown, it will be understood that any radical or species that can be reacted to form a new species measurable by laser absorption spectroscopy can be used according to the embodiments described herein.

[0076] In one embodiment, process 1080 may be followed by step 1084, which includes measuring a second species in an absorption chamber. In one embodiment, the absorption chamber may be similar to either a measuring cell or measuring chamber as described in more detail herein. For example, the absorption chamber may include a first window and a second window on either side of the chamber. A light source (e.g., a laser) may emit light that passes through the first and second windows. The light source may be optically coupled to a photodetector to determine the level of absorption provided by the second species. In some embodiments, the absorption chamber may be a separate chamber from the one in which the chemical reaction takes place. In other embodiments, the absorption chamber may be the same chamber in which the chemical reaction takes place.

[0077] Referring to Figures 11A and 11B, graphs showing the relationship between measured partial pressure and etching rate are presented. As shown in Figure 11A, the HF partial pressure rises to approximately 125W, then decreases, and rises again to 175W. Similarly, the etching rate for a power sweep shows the same decrease and subsequent increase. In other words, the measurement of partial pressure reflects the etching rate. Furthermore, as shown in Figure 11B, there is a strong linear trend between the etching rate data and the HF partial pressure data. Thus, it is possible to directly correlate knowledge of the HF partial pressure with the expected etching rate on the substrate.

[0078] Referring here to Figure 12, a block diagram illustrating a computer system 1200 as an example of a processing tool is shown according to one embodiment. In one embodiment, the computer system 1200 is connected to a processing tool and controls the processing within the processing tool. The computer system 1200 may be connected to (e.g., networked) other machines in a local area network (LAN), intranet, extranet, or internet. The computer system 1200 may act as a server or client machine in a client-server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The computer system 1200 may be a personal computer (PC), tablet PC, set-top box (STB), personal digital assistant (PDA), mobile phone, web appliance, server, network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or different) that specify the actions performed by that machine. Furthermore, although only a single machine is shown as computer system 1200, the term “machine” should also be interpreted to include any set of machines (e.g., computers) that individually or collectively execute a set (or set) of instructions in order to perform any one or more of the methods described herein.

[0079] The computer system 1200 may include a computer program product or software 1222 having a non-transient, machine-readable medium on which instructions are stored, and the instructions may be used to program the computer system 1200 (or other electronic device) to perform a process according to the embodiment. The machine-readable medium includes any mechanism for storing or transmitting information in a machine (e.g., computer)-readable form. For example, the machine-readable (e.g., computer-readable) medium includes machine (e.g., computer)-readable storage media (e.g., read-only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, etc.), machine (e.g., computer)-readable transmission media (e.g., propagated signals in electrical, optical, acoustic, or other forms (e.g., infrared signals, digital signals, etc.)), etc.

[0080] In one embodiment, the computer system 1200 includes a system processor 1202, a main memory 1204 (for example, a read-only memory (ROM), flash memory, a dynamic random access memory (DRAM) such as synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM)), a static memory 1206 (for example, a flash memory, a static random access memory (SRAM)), and a secondary memory 1218 (for example, a data storage device), all of which communicate with each other via a bus 1230.

[0081] The system processor 1202 represents one or more general-purpose processing units, such as a microsystem processor or a central processing unit. More specifically, the system processor may be a complex instruction set computing (CISC) microsystem processor, a reduced instruction set computing (RISC) microsystem processor, a very long instruction word (VLIW) microsystem processor, a system processor that executes other instruction sets, or a system processor that executes a combination of instruction sets. The system processor 1202 may also be one or more special-purpose processing units, such as an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a digital signal system processor (DSP), or a network system processor. The system processor 1202 is configured to execute processing logic 1226 for performing the steps described herein.

[0082] The computer system 1200 may further include a system network interface device 1208 for communicating with other devices or machines. The computer system 1200 may also include a video display unit 1210 (e.g., a liquid crystal display (LCD), a light-emitting diode (LED), or a cathode ray tube (CRT)), an alphanumeric input device 1212 (e.g., a keyboard), a cursor control device 1214 (e.g., a mouse), and a signal generating device 1216 (e.g., a speaker).

[0083] The secondary memory 1218 may include a machine-accessible storage medium 1232 (or more specifically, a computer-readable storage medium) containing one or more instruction sets (e.g., software 1222) that embody any one or more of the methods or functions described herein. The software 1222 may also reside, all or at least partially, within the range of the main memory 1204 and / or the system processor 1202 while being executed by the computer system 1200, the main memory 1204 and the system processor 1202 may also constitute a machine-readable storage medium. The software 1222 may further be transmitted or received over the network 1220 via a system network interface device 1208. In one embodiment, the network interface device 1208 may operate using RF coupling, optical coupling, acoustic coupling, or inductive coupling.

[0084] In one exemplary embodiment, the machine-accessible storage medium 1232 is shown as a single medium, but the term “machine-readable storage medium” should be interpreted to include a single or multiple mediums (e.g., a centralized or distributed database, and / or associated caches and servers) that store one or more instruction sets. The term “machine-readable storage medium” should also be interpreted to include any medium capable of storing or encoding a set of instructions for execution by a machine, which causes the machine to execute any one or more of the methods. Accordingly, the term “machine-readable storage medium” should be interpreted to include, but not be limited to, solid memory, optical media, and magnetic media.

[0085] In the aforementioned specification, specific exemplary embodiments have been described. It will be apparent that various modifications can be made to these exemplary embodiments without departing from the scope of the following claims. Accordingly, this specification and the drawings should be considered illustrative, not limiting.

Claims

1. It is a semiconductor processing tool, A plasma source for generating radicals, A processing chamber connected to the plasma source, A pump connected to the processing chamber, A sampling line configured to take a sample of the radical, The sampling line is provided, A reaction chamber configured to react the radical with a first species to form a second species measurable using laser absorption spectroscopy, and An absorption chamber configured to measure the amount of laser absorption of the second species corresponding to the radical concentration. Semiconductor processing tools, including...

2. The semiconductor processing tool according to claim 1, wherein the sampling line is configured to take a sample from between the plasma source and the processing chamber.

3. The semiconductor processing tool according to claim 1, wherein the sampling line is configured to take a sample from the processing chamber.

4. The semiconductor processing tool according to claim 1, wherein the sampling line is configured to take a sample downstream of the processing chamber.

5. The semiconductor processing tool according to claim 1, wherein the downstream side of the sampling line is connected to the pump.

6. The reaction chamber A first gas input line connected to the plasma source, A second gas input line connected to the reaction gas source, The output gas wire connected to the absorption chamber, A semiconductor processing tool according to claim 1, including the following:

7. The semiconductor processing tool according to claim 6, further comprising a temperature measuring device in the reaction chamber.

8. The semiconductor processing tool according to claim 6, wherein the reaction chamber further includes a transducer for controlling the pressure within the reaction chamber.

9. The aforementioned absorption chamber A third gas input line connected to the output gas line of the reaction chamber, A second gas output line connected to the pump, A first window on the first surface of the absorption chamber, A second window on the second surface of the absorption chamber, opposite to the first surface, A light source configured to emit light through the first window, A photodetector configured to receive light through the second window, A semiconductor processing tool according to claim 6, including the following:

10. The semiconductor processing tool according to claim 9, further comprising a temperature measuring device in the absorption chamber.

11. The semiconductor processing tool according to claim 9, wherein the absorption chamber further includes a transducer for measuring and / or controlling the pressure within the absorption chamber.

12. The semiconductor processing tool according to claim 1, wherein the reaction chamber and the absorption chamber are configured to be a single chamber.

13. A method for determining the radical concentration, Generating radicals using a plasma source, The radicals are flowed into the processing chamber, The aforementioned radical sample is passed through a sampling line, The radical and the first species are reacted in the reaction chamber of the sampling line to form a second species that can be measured using laser absorption spectroscopy. Measuring the laser absorption amount of the second species in the absorption chamber of the sampling line, wherein the measured value of the second species corresponds to the concentration of the radical, A method for determining radical concentration, including [specific radicals].

14. The method according to claim 13, wherein the radical comprises carbon, nitrogen, fluorine, chlorine, oxygen, sulfur, phosphorus, silicon, or hydrogen.

15. where the second species is HF, HCl, CO, CO ２ , H ２ O, OH, NH, NH ２ , NH ３ , HS, H ２ S, PH, PH ２ , PH ３ , C ｘ H ｙ , SiH, SiH ２ , SiH ３ , SiH ４ The method according to claim 14, comprising

16. The method according to claim 13, wherein the plasma source is a remote plasma source.

17. The method according to claim 13, wherein the reaction of the radical with the first species is carried out in a first chamber, and the first chamber is different from the absorption chamber.

18. It is a semiconductor processing tool, A remote plasma source for generating radicals, A processing chamber fluidly connected to the aforementioned remote plasma source, A pump fluidly connected to the processing chamber, A sampling line that is fluidly parallel to the processing chamber, The sampling line is provided, A reaction chamber configured to react the radical with a first species to form a second species measurable using laser absorption spectroscopy, and An absorption chamber configured to measure the amount of laser absorption of the second species corresponding to the radical concentration. Semiconductor processing tools, including...

19. The semiconductor processing tool according to claim 18, wherein the reaction chamber and the absorption chamber are combined as a single chamber.

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