Real-time monitoring method and device for plasma chamber wall condition

Abstract

The substrate processing system includes a processing chamber. A base and a nozzle are arranged in the processing chamber. A surface plasmon resonance (SPR) fiber has a central portion arranged in the processing chamber and opposite ends arranged outside the processing chamber. A light source provides input light at one end of the SPR fiber, and a detector receives output light from the other end of the SPR fiber. Surface plasmon waves and evanescent waves constitute the output light, which is processed and analyzed to determine the condition of the processing chamber.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Utility Patent Application No. 15 / 824,061, filed on November 28, 2017. The entire disclosure of the above-referenced application is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to substrate processing systems, more specifically, to monitoring conditions within a processing chamber in a substrate processing system, and more specifically, to real-time monitoring of conditions within a processing chamber in a substrate processing system. More specifically, the present disclosure relates to in-situ real-time monitoring of conditions within a processing chamber in a substrate processing system. Background Art

[0004] The background description provided herein generally gives the context of the present disclosure. To the extent described in this background section, the work of the inventors named in this application, as well as aspects of the description that may not otherwise be considered prior art at the time of filing, are not explicitly or implicitly admitted to be prior art for the present disclosure.

[0005] The substrate processing system can be used to etch and / or otherwise process a substrate (e.g., a semiconductor wafer). The substrate can be arranged on a susceptor in a processing chamber of the substrate processing system. For example, during etching in a plasma etcher, a gas mixture including one or more precursors is introduced into the processing chamber, and a plasma is excited to etch the substrate.

[0006] It is very useful to monitor the conditions within a semiconductor processing chamber so that the process can be optimized. The conditions within the processing chamber can, for example, indicate the need for cleaning, or can indicate whether the processing chamber has been sufficiently "seasoned" to be in optimal conditions for wafer manufacturing. In one aspect, "seasoning" can refer to the conditions of the processing chamber at a particular time, or can refer to the steady-state conditions of the processing chamber.

[0007] It is known to use a device located outside the processing chamber to monitor the processing chamber conditions. The conditions inside the semiconductor processing chamber are very detrimental to many devices. The processing chamber conditions can be observed through one or more windows in the processing chamber. For example, it is known to position a camera or other sensor at one of the windows to observe the conditions inside the chamber.

[0008] Figure 1An example of a substrate processing chamber 500 for performing etching using RF plasma is shown. The substrate processing chamber 500 includes a processing chamber 502 that surrounds the other components of the substrate processing chamber 500 and contains the RF plasma. The substrate processing chamber 500 includes an upper electrode 504 and a pedestal 506 including a lower electrode 507. An edge coupling ring 503 is supported by the pedestal 506 and is arranged around a substrate 508. One or more actuators 505 can be used to move the edge coupling ring 503. During operation, a substrate 508 is arranged on the pedestal 506 between the upper electrode 504 and the lower electrode 507.

[0009] By way of example only, the upper electrode 504 may include a showerhead 509 that introduces and distributes process gases. The showerhead 509 may include a stem portion, one end of which is connected to the top surface of the processing chamber. The base is typically cylindrical and extends radially outward from the opposite end of the stem portion at a position spaced apart from the top surface of the processing chamber. The substrate-facing surface or panel of the base of the showerhead includes a plurality of holes through which process gases or purge gases flow. Alternatively, the upper electrode 504 may include a conductive plate and the process gas may be introduced in another manner. The lower electrode 507 may be arranged in a non-conductive pedestal. Alternatively, the pedestal 506 may include an electrostatic chuck including a conductive plate that acts as the lower electrode 507.

[0010] The RF generation system 510 generates an RF voltage and outputs the RF voltage to one of the upper electrode 504 and the lower electrode 507. The other of the upper electrode 504 and the lower electrode 507 may be DC grounded, AC grounded, or floating. By way of example only, the RF generation system 510 may include an RF voltage generator 511 that generates an RF voltage that is fed to the upper electrode 504 or the lower electrode 507 by a matching and distribution network 512. In other examples, the plasma may be inductively or remotely generated.

[0011] The gas delivery system 530 includes one or more gas sources 532-1, 532-2, ... and 532-N (collectively referred to as gas sources 532), where N is an integer greater than zero. The gas source supplies one or more precursors and mixtures thereof. The gas source can also supply purge gas. Vaporized precursors can also be used. The gas source 532 is connected to the manifold 540 through valves 534-1, 534-2, ... and 534-N (collectively referred to as valves 534) and mass flow controllers 536-1, 536-2, ... and 536-N (collectively referred to as mass flow controllers 536). The output of the manifold 540 is fed to the processing chamber 502. By way of example only, the output of the manifold 540 is fed to the showerhead 509.

[0012] Heater 542 can be connected to a heater coil (not shown) disposed on pedestal 506. Heater 542 can be used to control the temperature of pedestal 506 and substrate 508. Valve 550 and pump 552 can be used to exhaust reactants from process chamber 502. Controller 560 can be used to control components of substrate processing chamber 500. Controller 560 can also be used to control actuator 505 to adjust the position of one or more portions of edge coupling ring 503.

[0013] A robot 570 and a sensor 572 can be used to measure corrosion of the edge coupling ring. In some examples, the sensor 572 can include a depth gauge. The robot 570 can bring the depth gauge into contact with the edge coupling ring to measure corrosion. Alternatively, a laser interferometer (with or without the robot 570) can be used to measure corrosion without direct contact. The robot 570 can be omitted if the laser interferometer can be positioned with a direct line of sight to the edge coupling ring.

[0014] Figure 2A An example of a method for detecting conditions at a chamber wall is shown. Figure 1 There are many components in Figure 2A 1 , semiconductor processing chamber 100 includes pedestal 110 upon which electrostatic chuck (ESC) 115 may be mounted. Wafer or substrate 120 is positioned on the ESC.

[0015] At the top of the processing chamber, the conduit 130 transfers the plasma to the showerhead 135, which distributes the plasma in the processing chamber. As the substrate is processed, there may be accumulation on the chamber walls. A detection device includes a light source 170 and a camera / detector 175. The light source 170 shines light through a first opening 180 onto a reflector 165 at the opposite end of the processing chamber. The camera / detector 175 picks up the light reflected from the reflector 165 through a second opening 185. The controller 160 communicates with the camera / detector 175 to operate the camera and receive output from the camera / detector. The controller 160 also controls the operation of the light source 170. When the detection device is not operating or the processing chamber is not in use, the shutters 190, 195 operate to cover the windows 180, 185, respectively.

[0016] The controller 160 may process the data from the camera / detector 175 using known signal processing algorithms and / or other computing techniques to obtain information about the condition of the walls in the process chamber 100. Alternatively, the controller 160 may transmit the obtained data to other processing equipment (not shown here for ease of description) for this purpose.

[0017] In operation, anything that builds up on the chamber walls will also build up on the reflector 165, thereby affecting the reflector's ability to reflect light from the light source 170 to the camera / detector 175. The controller 160 takes the amount of light received by the camera / detector 175 that is reflected from the reflector 165 and calculates / estimates the amount of buildup on the reflector given the light output by the light source 170 and the material deposited on the chamber walls (and therefore on the reflector 165).

[0018] Buildup will also form on the windows 180, 185 through which transmitted light enters and through which reflected light exits. As an approximation, to make calculations easier, it can be assumed that the amount of buildup on the windows is the same as the amount of buildup on the mirrors.

[0019] Figure 2B Shows Figure 2A A variation of the arrangement in which the camera / detector 175 and the window 185 are positioned with respect to the Figure 2A The side of the system that is located opposite to the process chamber. Figure 2B The method eliminates the need for mirrors within the processing chamber 100. Again, as an approximation, it can be assumed that the amount of buildup on window 185 will be the same as the amount of buildup on window 180 for ease of calculation.

[0020] Figure 2A There are many problems with the device and detection method. Figure 2AOne problem with the system is that the light from the light source 170 must be tightly focused on the reflector 165 so that what is returned from the reflector 165 is a reliable indication of the light that the light source 170 is providing. The light source 170 may be a laser or other coherent light source that is capable of being tightly focused on the reflector 165. Movement of any of the several elements in FIG. 2 may affect the ability of the camera / detector 175 to properly receive the reflected light. For example, movement of the light source 170 outside the processing chamber, or movement of the reflector 165 inside the processing chamber, or movement of the processing chamber itself may require that the light source 170 be refocused onto the reflector 165. Additionally, movement of the reflector 165 or movement of the processing chamber containing the reflector may require repositioning the camera / detector 175 because the angle of reflection from the reflector 165 may change. As a result of all of these possibilities, the light source 170 and / or the camera / detector 175 must be frequently repositioned / refocused. Another problem is that just as there is buildup on the reflector 165, there will also be buildup on the windows 180, 185, thereby affecting not only the amount of light provided by the light source 170, but also the amount of light detected by the camera / detector 175. Although it can be assumed that the material buildup on the chamber walls (and therefore on the reflectors and windows) is uniform, this may not be the case depending on the process used. As a result, given the different locations of the reflector 165 and windows 180, 185, there may be different amounts of buildup at different locations, making it difficult to provide a reliable estimate of the buildup on the windows.

[0021] Figure 2B The method eliminates the detection and accuracy issues associated with the mirror 165. However, since the windows 180, 185 are on opposite sides of the processing chamber, Figure 2B The method still has the problem of different amounts of buildup in different parts of the processing chamber. In addition, by using direct transmission of light instead of reflective transmission, Figure 2B The method improves the focusing problems associated with the movement of the light source 170, the camera / detector 175, or the processing chamber 100. However, those focusing problems will still exist to some extent.

[0022] Efforts have been made to provide detection equipment within the processing chamber to provide a more direct measurement. A significant difficulty with this approach is the hostile environment that the plasma provides for the equipment.

[0023] More accurate monitoring of process chamber conditions would be useful. Summary of the invention

[0024] A substrate processing system comprises: a processing chamber having a chamber wall; and a susceptor arranged in the processing chamber to hold a substrate for processing. The substrate processing system comprises a showerhead arranged in the processing chamber to distribute plasma in the chamber. The substrate processing system also comprises a detector system configured to detect the condition of the chamber wall. The detector system comprises a surface plasmon resonance (SPR) fiber having a first end and a second end located outside the processing chamber, and an inner portion of the SPR fiber located inside the processing chamber. A light source provides input light to a first end of a first SPR fiber. A controller is configured to control the amount of light provided to the first end of the SPR fiber and receive light as output light at the second end of the SPR fiber. The controller analyzes the input light and the output light to determine the condition of the chamber wall.

[0025] In one aspect, one or more cladding portions on the SPR fiber can be removed to provide one or more openings on a portion of the SPR fiber within the process chamber. The openings are filled with inserts configured to provide surface plasmon waves and evanescent waves, the characteristics of which are used to determine conditions within the process chamber.

[0026] In one feature, the openings in the SPR fibers can be close enough to each other, but far enough apart to determine conditions in different parts of the process chamber. In another feature, the openings in the SPR fibers can be far enough apart to be spaced around the process chamber to determine conditions on opposite sides of the process chamber.

[0027] In one feature, multiple SPR fibers can be provided in different portions of the process chamber. In another feature, an SPR fiber can be used as a reference disposed outside the process chamber, and the controller uses the output light from the reference SPR fiber to compare with the output light of the SPR fiber within the process chamber to determine a baseline for determining the condition of the chamber wall.

[0028] In other features, the input light can be a laser, such as a quantum cascade laser (QCL), which provides light transmission in the appropriate infrared (IR) band. In other features, the laser can be a distributed feedback laser (DFB), which provides light transmission in a narrower wavelength range or even at a specific wavelength.

[0029] A method for measuring the condition of the inner wall of a processing chamber in a substrate processing system includes measuring surface plasmon waves and evanescent waves generated in the processing chamber. In one aspect, the SPR fibers and related equipment described earlier in this section can be used to generate those waves. The resulting measurements can be used to determine the condition of the chamber walls.

[0030] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the accompanying drawings.The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

[0031] BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present disclosure will be more fully understood through the detailed description and accompanying drawings, in which:

[0033] Figure 1 is a functional block diagram of an example of a substrate processing chamber including a pedestal and a showerhead assembly;

[0034] Figure 2A is a functional block diagram of an example of a substrate processing chamber including a pedestal and a showerhead assembly and an example of an apparatus for detecting conditions within the processing chamber according to an aspect of the present disclosure;

[0035] Figure 2B is a functional block diagram of an example of a substrate processing chamber including a pedestal and a showerhead assembly and an example of an apparatus for detecting conditions within the processing chamber according to an aspect of the present disclosure;

[0036] Figure 3A is a functional block diagram of an example of a substrate processing chamber including a pedestal and a showerhead assembly and an example of an apparatus for detecting conditions within the processing chamber according to an aspect of the present disclosure;

[0037] Figure 3B is a functional block diagram of an example of a substrate processing chamber including a pedestal and a showerhead assembly and an example of an apparatus for detecting conditions within the processing chamber according to an aspect of the present disclosure;

[0038] Figure 4 is a functional block diagram of an example of a substrate processing chamber including a pedestal and a showerhead assembly and an example of an apparatus for detecting conditions within a processing chamber according to another aspect of the present disclosure;

[0039] Figure 5 is an illustrative diagram showing light passing through an SPR fiber having one opening according to an aspect of the present disclosure;

[0040] Figure 6 is an illustrative diagram showing light passing through an SPR fiber having two openings according to an aspect of the present disclosure;

[0041] Figure 7 is an illustrative diagram showing light passing through an SPR fiber having one opening and a coating on the exposed fiber portion according to one aspect of the present disclosure;

[0042] Figure 8 is an illustrative diagram showing light passing through an SPR fiber having two openings and a coating on the exposed fiber portion according to an aspect of the present disclosure;

[0043] Fig. 9 is a diagram of a portion of an SPR fiber having an opening and a material covering the opening;

[0044] Fig.10 is a diagram of a portion of an SPR fiber having two openings and a material covering the openings;

[0045] Fig.11 is a plan view of a liner in a substrate processing chamber according to one aspect;

[0046] Fig.12 yes Fig.11 an enlarged view of a portion of the pad shown;

[0047] Fig.13 It is a graph of light intensity versus wavelength.

[0048] In the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0049] Reference now Figure 3A , features of placing an SPR fiber in a substrate processing chamber, and features of associated equipment that enable the fiber to be used as a detector for detecting conditions within the chamber, will be described. This portion of the specification focuses on detectors and detection methods according to features of the present disclosure that enable direct measurement of internal processing chamber conditions. For the sake of brevity and clarity, the details of the various elements of the processing chamber (including the ESC) will not be repeated here.

[0050] exist Figure 3A In, with Figure 2A and Figure 2B Certain elements that are identical to those in the drawings have the same reference numerals. Figure 3A There is a controller 200, which includes a light source, a light detector and a processor on the one hand. SPR fiber 210 extends through feedthroughs 340, 345. Such feedthroughs are well known to those of ordinary skill in the art and will not be described in detail here. One end of the SPR fiber 210 receives input light from a light source in the controller 200 and provides output light to a light detector in the controller 200. SPR fibers such as fiber 210 have an opening 220 in the outer cladding to expose the fiber therein. As will be explained, based on the known physical and optical properties of the fiber and the condition in which the unclad portion of the fiber is exposed within the processing chamber 100, the material placed above the opening 220 in the SPR fiber 210 will affect the passage of light from the input end to the output end of the fiber in a measurable manner.

[0051] Figure 3AAn SPR fiber 210 is shown with an exposed portion in the process chamber 100. In addition, Figure 3A Also shown are respective feedthroughs 340, 345 that receive respective ends of the SPR fibers 210. In one aspect, the ends of a particular SPR fiber can pass through the same feedthrough.

[0052] The insert 225, which will be described in more detail herein, covers the exposed fiber to protect it from conditions inside the processing chamber 100. The insert 225 also has known light transmission and reflection properties. When light passes through the SPR fiber 210, the insert 225 will also affect the passage of light from the input end to the output end of the fiber in a known manner.

[0053] In order to prepare the detection system for operation, the light detection and processing system obtains information about how the SPR fiber 210 processes the transmission and reception of light in the chamber 100. Before running the substrate processing system, spectral data of the SPR fiber 210 in the processing chamber 100 is obtained to allow the identification of a baseline. The baseline can be determined in several ways. On the one hand, the baseline can be first identified by taking a light measurement using a purely uncovered, unclad opening of the SPR fiber 210 in the processing chamber 100, and then taking the same measurement after adding the insert 225. On the other hand, the baseline can be identified by measuring only the SPR fiber 210 with the insert 225. On the other hand, the baseline can be identified by measuring the light passing through the fully covered clad fiber.

[0054] After completing the baseline identification, other reference measurements can be obtained. For example, the substrate processing system can be run on a coupon placed on the ESC. With the operation of the substrate processing system, the deposited material will accumulate on various exposed parts of the processing chamber 100, including the SPR fiber 210. Different deposition materials also have different spectral characteristics, which can uniquely identify them. When a specific deposition material is introduced into the processing chamber 100 and deposited on the coupon, light measurement can be performed. Deposition can occur for a period of time, during which the thickness of the material deposited on the SPR fiber 210 will increase. Periodic or continuous measurements of light transmitted by the SPR fiber 210 are performed and associated with the deposition thickness. Alternatively, the processing chamber 100 can be opened periodically and thickness measurements are performed directly. It is also possible to directly perform thickness measurements of the material deposited on the chamber wall and compare it with the deposition thickness measured on the insert 225 in the SPR fiber 210.

[0055] In one aspect, multiple fibers may be arranged at multiple locations around the processing chamber 100 and a respective feedthrough may be provided for a respective end of each fiber. Figure 3B shows the Figure 3AA second SPR fiber arrangement is shown on the opposite side of the first SPR fiber arrangement.

[0056] Figure 3B There is a controller 200', which in one aspect includes a light source, a light detector and a processor. In addition to the SPR fiber 210 extending through the feedthroughs 340, 345, another SPR fiber 210' extends through the feedthroughs 340', 345'. The SPR fiber 210 has been discussed above and will not be repeated here for the sake of brevity. One end of the SPR fiber 210' receives input light from a light source in the controller 200' and provides output light to a light detector in the controller 200'. The SPR fiber (e.g., fiber 210') has an opening 220' in the outer cladding to expose the fiber therein. As will be explained, based on the known physical and optical properties of the fiber and the condition in which the unclad portion of the fiber is exposed within the processing chamber 100, the material placed above the opening 220' in the SPR fiber 210' will affect the passage of light from the input end to the output end of the fiber in a measurable manner.

[0057] Figure 3B An SPR fiber 210' is shown with an exposed portion in the process chamber 100. In addition, Figure 3B Also shown are respective feedthroughs 340', 345' that receive respective ends of the SPR fibers 210'. In one aspect, the ends of a particular SPR fiber can pass through the same feedthrough.

[0058] Insert 225' covers the exposed fiber to protect it from the interior of process chamber 100. Insert 225' also has known light transmission and reflection properties. When light passes through SPR fiber 210', insert 225' will also affect the passage of light from the input end to the output end of the fiber in a known manner.

[0059] Figure 3B The system shown otherwise operates equivalently to Figure 3A The system shown.

[0060] Figure 4 A detection system for use in a substrate processing chamber according to one aspect of the present disclosure is shown. For ease of discussion, other elements of the processing chamber have been removed. The SPR fiber with two openings (the fiber portion with the openings is located inside the substrate processing chamber) and the reference fiber located outside the processing chamber (without such openings) are shown in a schematic manner and are not intended to show the actual position inside and outside the processing chamber, and are not drawn to scale.

[0061] A closer look Figure 4, the substrate processing system 300 has a processing chamber 350 with feedthroughs 340, 345. The SPR fiber 310 passes through the feedthroughs 340, 345. The SPR fiber 310 has an exposed opening on which inserts 330, 335 are disposed. A collection / processing device 390 communicates with a light source 380 that passes light through one end of the SPR fiber 310. A detector 385 receives light that passes through the other end of the SPR fiber 310 and transmits information related to the detected light to the collection / processing device 390.

[0062] In one aspect, a second or reference SPR fiber 320 can pass light from a light source 380 to a detector 385. The second SPR fiber 320 has the same core and cladding as the SPR fiber 310, has no openings, and is disposed outside the process chamber 350 and can be used as a reference for information received from the SPR fiber 310 as light passes from the light source 380 to the detector 385. For example, when the walls of the chamber 350 are clean and / or before the substrate processing system 300 begins or resumes operation, the second SPR fiber 320 can provide baseline data for comparison with data obtained from processing light through the SPR fiber 310. The baseline data can also be compared with subsequent data obtained from processing light through the SPR fiber 310 as the system 300 is operated and material accumulates on the walls of the process chamber 350. In one aspect, in addition to viewing the difference between baseline data and pre-operational data and / or inter-operational data from SPR fiber 310, and viewing the difference between pre-operational data and / or inter-operational data from SPR fiber 310 and intra-operational data from SPR fiber 310, other information about the condition of the walls of process chamber 350 can also be provided.

[0063] Let us now look more closely at an SPR fibre forming part of a detection system according to aspects of the present disclosure. Figure 5 and Figure 6 An open portion of the SPR fiber 500 is shown. Figure 5 A single exposed portion 530 is shown in fiber 500 between cladding portions 510 and 520 covering the fiber core. Figure 6 Two exposed portions 530, 550 are shown. The exposed portion 530 is between the cladding portions 510 and 520, and the exposed portion 550 is between the cladding portions 520 and 540.

[0064] Figure 6Exposed portions 530, 550 are schematically shown. The spacing between exposed portions 530, 550 may be determined as desired to facilitate detection of material buildup in different portions of the substrate processing chamber. Moreover, according to an aspect of the present disclosure, more than two exposed portions 530, 550 may be present in the SPR fiber 500.

[0065] Figure 7 and Figure 8 Shown with Figure 5 and Figure 6 A similar view, but additionally showing a thin layer of metal film disposed over exposed portion 530. Membrane portion 560 extends all the way around exposed portion 530. Membrane portion 565 extends partially around exposed portion 530 to show exposed and covered portions of fiber 500. Membrane portions 560, 565 may be made of gold, as is common with SPR fibers. Gold is not plasma resistant and will contaminate the processing chamber when exposed to plasma etching. Therefore, as will be discussed below with respect to Fig. 9 and Fig.10 As discussed, other materials disposed on the portion of the membrane closest to the exposed portion will be more resistant to the plasma and avoid contamination issues.

[0066] and Figure 6 The same is shown schematically Figure 8 The spacing between the exposed portions 530, 550 can be determined as desired to facilitate detection of material buildup in different portions of the substrate processing chamber.

[0067] Similar to Figure 7 and Figure 8 , Fig. 9 and Fig.10 Parts of an SPR fiber with one opening and two openings are shown, respectively. Figure 6 and Figure 8 Same, in Fig.10 The openings in are schematically depicted according to their spacing and are not drawn to scale.

[0068] exist Fig. 9 and Fig.10 , SPR fiber 600 has an inner portion 605 having a diameter D. In one aspect, inner portion 605 is configured to provide total internal reflection or TIR up to a particular angle of incidence that depends, among other things, on the diameter D and the refractive index of inner portion 605. Looking more closely Fig. 9, a metal layer 610 is deposited over the exposed inner portion 605. In one aspect, the metal layer 610 is made of gold. A dielectric material 620 is provided over the metal layer 610, and a dielectric sensing layer 630 is provided over the dielectric material 620. Layers 610, 620, and 630 together correspond to inserts 225, 330, and 335 in FIGS. 3 and 4. Fig. 9 and Fig.10 , the inner portion 605 is exposed over its entire periphery, although this is not necessary for operation.

[0069] Because, as previously discussed, metals such as gold may not be resistant to plasma etching, gold may contaminate the processing chamber. As a result, it is necessary to provide a layer on layer 610 (which may be a metal layer of gold) that has high reflectivity, sufficient etching resistance, and an optical index that allows evanescent waves. Materials such as MgF2 and BaF2 may be suitable for protecting the gold layer from HF, HCl, and / or fluorine reactive gases. When MgF2 or BaF2 is used, aluminum can be used instead of gold. Chromium (Cr) is also plasma resistant and can be used instead of gold with or without a MgF2 or BaF2 coating. In one aspect, the dielectric material 620 will also have favorable plasma resistant properties.

[0070] In one aspect, layer 610 can be made of gold and can be 100 nm thick. Although layers 620 or 630 are shown in the figures as being thicker or of the same thickness, they can also be thinner, for example 1 to 5 nm.

[0071] Regarding the placement of the SPR fiber in the substrate processing chamber, in one aspect, reference is made to Fig.11 , the liner 1012 has a plurality of openings 1015. In one aspect, the liner 1012 is made of yttrium. Fig.11 SPR fibers 1030 are shown positioned within the interior of the liner 1012. The ends of the SPR fibers 1030 extend through openings 1015 to the exterior of the liner 1012. In one aspect, the fiber ends extending outside of the liner 1012 are inserted into yttrium tubes (not shown) to protect them from etchants in the substrate processing chamber.

[0072] In one aspect, a majority of the SPR fiber 1030 extends behind the liner 1012, with the active or sensing region within the liner 1012 aligned with one of the openings 1015 that can be used for high gas conduction. In this manner, a majority of the length of the SPR fiber 1030 can be protected from direct plasma effects. Fig.11, SPR fibers 1030, 1030' of varying lengths are shown within the liner 1012. To protect the fibers 1030, 1030' from direct plasma, only the exposed (declad) portions of the fibers 1030, 1030' may be positioned within the liner 1012. In one aspect, the SPR fibers 1030' may be positioned horizontally (rather than vertically) within the processing chamber, in which case the SPR fibers 1030' would extend through two of the openings 1015, as shown.

[0073] and Fig.11 similar, Fig.12 An enlarged view of the openings 1015 is shown, with the SPR fiber 1030 extending through one of the openings 1015. A portion of the SPR fiber 1030 is shown inside the liner 1012 and is exposed to direct plasma during operation of the substrate processing chamber. For ease of description and illustration, Fig.11 and Fig.12 The SPR fibers 1030 (or Fig.11 In the case of SPR fiber 1030'), the unclad portion of the SPR fiber.

[0074] In the case of a substrate processing chamber for dielectric etching, a shroud 1050 can surround the liner 1012. In one aspect, the shroud 1050 is made of silicon. The ends of the SPR fibers 1030, 1030' can extend through the shroud 1050. In that case, instead of being within the liner 1012, the SPR fibers 1030, 1030' can remain outside the liner 1012, with the exposed (unclad) portion of the SPR fibers 1030, 1030' aligned with one of the openings 1015. The portions of the SPR fibers 1030, 1030' that extend behind the shroud 1050 can be inserted into silicon tubes to protect them from the etchants in the substrate processing chamber.

[0075] The working principles of SPR fibers are well known and will not be described here for the sake of brevity. As a brief overview, looking more closely at the operation of the SPR fiber 600, due to the interface between the metal layer 610 and the dielectric material 620, a surface plasmon wave (SPW) will propagate along the interface. In one aspect, the SPW is a p-polarized electromagnetic wave. When the wave is incident on the metal-dielectric interface so that the propagation constant (and the energy generated therewith) of the resulting evanescent wave (so-called because it decays exponentially with distance) equals the propagation constant of the SPW, strong light absorption will occur. The resulting output signal will drop significantly at a specific wavelength (the resonant wavelength). One way to express this resonant condition is as follows:

[0076]

[0077] The term on the left side of the above equation is due to the fact that light is incident at an angle θ through a c The propagation constant (K) of the evanescent wave generated by the attenuated total reflection (ATR) of an optical coupling device (such as a prism or optical fiber) inc ). The term on the right is the SPW propagation constant (K SP ), where ε mr is the metal dielectric constant (ε m ), and n s is the refractive index of the sensing (dielectric) layer.

[0078] In all of Figures 3-10, the SPR fibers are not drawn to scale. In particular, the openings in the fiber and the diameter of the fiber are not shown to scale. The wavelength of light passing through the fiber, as well as the formation of surface plasmon waves (SPWs) and evanescent waves near the exposed portion of the fiber, will be a function of the opening length and fiber diameter in addition to the criteria described previously.

[0079] Various types of materials are known to have plasma-resistant characteristics or capabilities, including, for example, oxides and nitrides of various elements, such as oxides and nitrides of zirconium and yttrium. Depending on the material accumulation to be monitored, and taking into account the spectral characteristics of these plasma-resistant materials, some such materials may be more suitable for use as coatings for SPR fibers than others. On the one hand, it is important to consider the type of material accumulation to be monitored. For example, oxides of silicon or chlorine or fluorides of carbon may accumulate on the walls of a chemical etching (CE) processing chamber. The material used for the insert in the exposed portion of the SPR fiber should have a transmission spectrum that is distinguishable from the spectrum of the material whose accumulation is being monitored.

[0080] With the foregoing in mind, zirconium nitride (ZrN) is one plasma resistant material that can be used. There are other materials that meet the criteria just listed.

[0081] Using an SPR fiber as a detector in a substrate processing chamber can provide several advantages. In no particular order, the advantages include the following. The structure can be simpler and the same detection and processing circuits and methods as existing measurement techniques can be used. The position of the fiber (especially the fiber opening) in the processing chamber is more flexible, as long as it is not affected by the process performed in the processing chamber.

[0082] Furthermore, rather than having to deal with material buildup at multiple locations around the walls of the substrate processing chamber, only the material buildup on the SPR fiber itself needs to be addressed. No estimate of buildup at multiple locations is required.

[0083] As mentioned previously, on the one hand, the input light can come from a QCL, and on the other hand, the input light can come from a DFB laser. One aspect of QCLs is that they can scan a larger band, such as from 5 to 12 microns, covering the signatures of multiple molecules in the infrared (IR) spectrum. This coverage is closely related to IR detectors that can cover a relatively large band in the IR domain. In contrast, DFB lasers can handle very narrow bands of wave numbers less than or equal to 1, which means that the use of DFB lasers will be primarily limited to detecting single molecules.

[0084] Fig.13 A graph of light intensity versus wavelength is shown. The solid straight line represents a state where there is no laser emission and therefore no absorption in the SPR fiber. The upward sloping solid line corresponds to the slope from the beginning of the band to the end of the band. The solid curve 1310 and the dashed curve 1320 depict peaks or valleys that are characteristic of a particular molecule. For example, during substrate processing, CF, CF x , SiCl x , SiO x , CH x Or OH (moisture) deposits may grow on the walls of the substrate processing chamber. The solid curve 1310 may represent a certain amount of deposits, while the dashed curve 1320 may represent a different amount of deposits, resulting in different amplitudes of peaks or valleys. The dotted line 1330 tracks the deviation caused by deposits on the chamber walls, and then returns to a state closer to the clean chamber walls (i.e., no deposits) after cleaning the walls.

[0085] In terms of detecting the accumulation on the unclad portion of the SPR fiber, various known techniques can be used to obtain and process the data generated by the transmission of light through the SPR fiber in the substrate processing chamber. On the one hand, separate measurements can be made and analyzed to determine the accumulation thickness. Measurements can be made between the operations of the substrate processing chamber. These operations may or may not be performed at fixed time intervals, but this is not important for the efficiency of the detection system. Depending on the process used and its duration, different operations of the substrate processing system may result in different accumulation amounts. On the other hand, multiple measurements can be made at specific intervals, and those measurements are integrated to determine the accumulation thickness, the accumulation rate, or other parameters related to determining the condition of the wall of the substrate processing chamber.

[0086] In one aspect, as described above, the open portion of the SPR fiber can be about 1 cm. The size of the opening can be optimized (made larger or smaller) to increase or minimize the absorption effective area. Moreover, as described above, it is possible to provide multiple openings in different areas of the processing chamber, which again hopefully does not affect the processing performed in the processing chamber. Using the known absorption characteristics at each opening and the known characteristics of the coating at each opening, conditions in different parts of the processing chamber can be observed while processing is being performed.

[0087] The foregoing description is merely illustrative in nature and is in no way intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in various forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited, because after studying the drawings, the specification and the appended claims, other modifications will become apparent. As used herein, the phrase "at least one of A, B and C" should be interpreted as meaning a logic (A or B or C) using a non-exclusive logical or (OR), and should not be interpreted as meaning "at least one of A, at least one of B and at least one of C". It should be understood that one or more steps in the method can be performed in different orders (or simultaneously) without changing the principles of the present disclosure.

[0088] In some implementations, the controller is part of a system, which can be part of the above examples. Such a system can include a semiconductor processing device, which includes one or more processing tools, one or more chambers, one or more platforms for processing, and / or specific processing components (wafer pedestals, gas flow systems, etc.). These systems can be integrated with electronic devices for controlling their operations before, during, and after the processing of semiconductor wafers or substrates. The electronic device can be referred to as a "controller", which can control various components or subcomponents of one or more systems. Depending on the processing requirements and / or the type of system, the controller can be programmed to control any process disclosed herein, including the delivery of process gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, position and operation settings, wafer transfer in and out of tools and other transfer tools and / or load locks connected to or connected to a specific system through an interface.

[0089] In general, a controller can be defined as an electronic device having various integrated circuits, logic, memory, and / or software that receive instructions, issue instructions, control operations, enable cleaning operations, enable endpoint measurements, etc. The integrated circuit can include a chip in the form of firmware that stores program instructions, a digital signal processor (DSP), a chip defined as an application specific integrated circuit (ASIC), and / or one or more microprocessors, or a microcontroller that executes program instructions (e.g., software). The program instructions can be instructions sent to the controller in the form of various individual settings (or program files) that define operating parameters for performing a specific process on or for a semiconductor wafer or system. In some embodiments, the operating parameters can be part of a recipe defined by a process engineer to complete one or more processing steps during the manufacture of one or more (kinds of) layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0090] In some implementations, the controller may be part of or coupled to a computer that is integrated with the system, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the "cloud" or all or part of a wafer fab host system that may allow remote access to wafer processing. The computer may enable remote access to the system to monitor the current progress of a manufacturing operation, check the history of past manufacturing operations, check trends or performance criteria for multiple manufacturing operations, change parameters of a current process, set processing steps to follow the current process, or start a new process. In some examples, a remote computer (e.g., a server) may provide a process recipe to the system via a network (which may include a local network or the Internet). The remote computer may include a user interface that enables input or programming of parameters and / or settings, which are then sent from the remote computer to the system. In some examples, the controller receives instructions in the form of data that specify parameters for each processing step to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process to be performed and the type of tool, and the controller is arranged to interface with or control the tool. Thus, as described above, the controller may be distributed, for example, by including one or more discrete controllers networked together and working toward a common purpose (e.g., the process and control described herein). An example of a distributed controller for such a purpose is one or more integrated circuits on a chamber communicating with one or more integrated circuits remotely (e.g., at a platform level or as part of a remote computer), which combine to control the process on the chamber.

[0091] Example systems may include, but are not limited to, plasma etch chambers or modules, deposition chambers or modules, spin rinse chambers or modules, metal plating chambers or modules, cleaning chambers or modules, chamfer edge etch chambers or modules, physical vapor deposition (PVD) chambers or modules, chemical vapor deposition (CVD) chambers or modules, atomic layer deposition (ALD) chambers or modules, atomic layer etch (ALE) chambers or modules, ion implantation chambers or modules, track chambers or modules, and any other semiconductor processing system that may be associated with or used in the manufacture and / or preparation of semiconductor wafers.

[0092] As described above, depending on one or more processing steps to be performed by the tool, the controller can communicate with one or more other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout the factory, a host computer, another controller, or tools used in material transport to transport wafer containers to and from tool locations and / or load ports in a semiconductor manufacturing facility.

Claims

1. A substrate processing system, comprising: a processing chamber having a chamber wall; a susceptor disposed in the processing chamber to hold a substrate for processing; a showerhead disposed in the processing chamber to distribute plasma in the processing chamber; and a detector system configured to detect a condition of the chamber wall, the detector system comprising: a first surface plasmon resonance (SPR) fiber having a first end and a second end located outside the process chamber, and an inner portion of the first SPR fiber located inside the process chamber; a light source that provides light as a first input light to the first end of the first SPR fiber; and a controller configured to control an amount of light provided to the first end of the first SPR fiber and to receive light at the second end of the first SPR fiber as a first output light, the controller analyzing the first input light and the first output light to determine a condition of the chamber wall, The first SPR fiber includes a first central fiber, the first central fiber has a first cladding surrounding the first central fiber, the first cladding has a first opening, the first opening is positioned so that the first opening is located inside the processing chamber, and the first SPR fiber also includes within the first opening: A first metal film disposed over the first central optical fiber; and A first layer of plasma resistant material is disposed above the first metal film.

2. The substrate processing system according to claim 1, wherein: The process chamber also includes a first feedthrough; and wherein the first SPR fiber extends through the first feedthrough. 3 . The substrate processing system of claim 2 , wherein the first end and the second end of the first SPR fiber extend through the first feedthrough.

4. The substrate processing system according to claim 2, wherein: The process chamber also includes a second feedthrough, and the first end of the first SPR fiber extends through the first feedthrough, and the second end of the first SPR fiber extends through the second feedthrough.

5. The substrate processing system according to claim 4, wherein: The first feedthrough and the second feedthrough are proximate to each other on one side of the process chamber.

6. The substrate processing system according to claim 5, wherein: The process chamber further includes a third feedthrough and a fourth feedthrough, and wherein the third feedthrough and the fourth feedthrough are on an opposite side of the process chamber from the first feedthrough and the second feedthrough.

7. The substrate processing system according to claim 1, wherein: The plasma resistant material includes a material selected from the group consisting of nitrides and oxides of zirconium and yttrium.

8. The substrate processing system according to claim 1, wherein: The first cladding has a second opening located within the processing chamber, and the first SPR fiber further includes within the second opening: A second metal film disposed over the first central optical fiber; and A second layer of plasma resistant material is disposed above the second metal film.

9. The substrate processing system according to claim 1, wherein: The detector system also includes a second SPR fiber having a first end and a second end located outside the process chamber, and an inner portion of the second SPR fiber located inside the process chamber on a side opposite the first SPR fiber; the light source providing light as second input light to the first end of the second SPR fiber; as well as The controller is configured to control the amount of light provided to the first end of the second SPR fiber and receive light at the second end of the second SPR fiber as second output light, the controller analyzing the second input light and the second output light to determine a condition of the chamber wall.

10. The substrate processing system according to claim 9, wherein: The second SPR fiber includes a second central fiber having a second cladding surrounding the second central fiber, the second cladding having a third opening, the third opening being positioned such that the third opening is located inside the processing chamber, the second SPR fiber further comprising within the third opening: A third metal film disposed over the second central optical fiber; and A third layer of plasma resistant material is disposed above the third metal film.

11. The substrate processing system according to claim 10, wherein: The second cladding has a fourth opening located within the processing chamber, and the second SPR fiber further includes within the fourth opening: a fourth metal film disposed over the second central optical fiber; and A fourth layer of plasma resistant material is disposed above the fourth metal film.

12. The substrate processing system of claim 4, wherein the detector system further comprises: a reference surface plasmon resonance (SPR) fiber having a first end and a second end and located outside the processing chamber; the light source providing light as reference input light to the first end of the reference SPR fiber; and The controller is configured to control the amount of light provided to the first end of the reference SPR fiber and receive light at the second end of the reference SPR fiber as reference output light, the controller comparing the reference output light with the first output light to determine a baseline for determining the condition of the chamber wall.

13. The substrate processing system of claim 12, the controller comparing the reference output light to the first output light after the chamber wall has been cleaned and prior to subsequent use of the substrate processing system.

14. A detector system in a substrate processing system, the substrate processing system comprising a processing chamber having a chamber wall and at least one feedthrough, a pedestal disposed in the processing chamber to hold a substrate for processing, and a showerhead disposed in the processing chamber to distribute plasma in the processing chamber; The detector system is configured to detect a condition of the chamber wall, the detector system comprising: a first surface plasmon resonance (SPR) fiber having a first end and a second end located outside the process chamber, and an inner portion of the first SPR fiber located inside the process chamber; a light source that provides light as a first input light to the first end of the first SPR fiber; and a controller configured to control an amount of light provided to the first end of the first SPR fiber and to receive light at the second end of the first SPR fiber as a first output light, the controller analyzing the first input light and the first output light to determine a condition of the chamber wall, The first SPR fiber includes a first central fiber, the first central fiber has a first cladding surrounding the first central fiber, the first cladding has a first opening, the first opening is positioned so that the first opening is located inside the processing chamber, and the first SPR fiber also includes within the first opening: A first metal film disposed over the first central optical fiber; and A first layer of plasma resistant material is disposed above the first metal film.

15. The detector system of claim 14, wherein: The first cladding has a second opening located within the processing chamber, and the first SPR fiber further includes within the second opening: A second metal film disposed over the first central optical fiber; and A second layer of plasma resistant material is disposed above the second metal film.

16. The detector system of claim 14, further comprising a second SPR fiber having a first end and a second end located outside the process chamber, and an inner portion of the second SPR fiber located inside the process chamber on an opposite side from the first SPR fiber; a light source that provides light as a second input light to the first end of the second SPR fiber; and The controller is configured to control the amount of light provided to the first end of the second SPR fiber and receive light at the second end of the second SPR fiber as second output light, the controller analyzing the second input light and the second output light to determine a condition of the chamber wall.

17. The detector system of claim 16, wherein: The second SPR fiber includes a second central fiber having a second cladding surrounding the second central fiber, the second cladding having a third opening, the third opening being positioned such that the third opening is located inside the processing chamber, the second SPR fiber further comprising within the third opening: A third metal film disposed over the second central optical fiber; and A third layer of plasma resistant material is disposed above the third metal film.

18. The detector system of claim 17, wherein: The second cladding has a fourth opening located within the processing chamber, and the second SPR fiber further includes within the fourth opening: a fourth metal film disposed over the second central optical fiber; and A fourth layer of plasma resistant material is disposed above the fourth metal film.

19. The detector system of claim 14, further comprising: a reference surface plasmon resonance (SPR) fiber having a first end and a second end and located outside the processing chamber; the light source providing light as reference input light to the first end of the reference SPR fiber; and The controller is configured to control the amount of light provided to the first end of the reference SPR fiber and receive light at the second end of the reference SPR fiber as reference output light, the controller comparing the reference output light with the first output light to determine a baseline for determining the condition of the chamber wall.

20. The detector system of claim 19, the controller comparing the reference output light to the first output light after the chamber walls have been cleaned and prior to subsequent use of the substrate processing system.

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