WO2019195100A1

WO2019195100A1 - Inline chamber metrology

Info

Publication number: WO2019195100A1
Application number: PCT/US2019/024823
Authority: WO
Inventors: Avishek GHOSH; Prerna Sonthalia Goradia; Robert Jan Visser
Original assignee: Applied Materials, Inc.
Priority date: 2018-04-02
Filing date: 2019-03-29
Publication date: 2019-10-10
Also published as: GB2587940A8; GB2587940B; JP7498225B2; TWI775689B; TW201945724A; JP2022160395A; KR20220140045A; JP7097458B2; GB202017339D0; JP2021519522A; KR20200128192A; DE112019001752T5; GB2587940A; TWI751412B; KR102454199B1; TW202212815A; CN112041977A

Abstract

Embodiments of the present disclosure relate to inspection of substrates undergoing vacuum processing. In one embodiment, a processing chamber includes a first view port to enable an emitter of electromagnetic radiation to illuminate a substrate in the processing chamber, a second view port to enable a detector to detect electromagnetic radiation scattered from the substrate, the electromagnetic radiation emitter, and the detector.

Description

INLINE CHAMBER METROLOGY

BACKGROUND

Field

[0001] Embodiments of the present disclosure generally relate to reduced- pressure processing systems and processing techniques. More particularly, embodiments of the present disclosure relate to techniques for direct inline monitoring of substrates in reduced-pressure processing systems.

Description of the Related Art

[0002] Semiconductor substrates are processed for a wide variety of applications, including the fabrication of integrated devices and microdevices. One technique for processing substrates includes exposing the substrate to gases at reduced pressures and causing the gases to deposit a material, such as dielectric material or a conductive metal, on a surface of the substrate. For example, epitaxy is a deposition process that may be used to grow a thin, high-purity layer, frequently of silicon or germanium, on a surface of a substrate (e.g., a silicon wafer). The material may be deposited in a cross-flow chamber by flowing a process fluid (e.g., a mixture of precursor gases and carrier gases) parallel to, and across, the surface of a substrate positioned on a support, and decomposing (e.g., by heating the process fluid to high temperatures) the process fluid to deposit a material from the process fluid onto the surface of the substrate.

[0003] At various times during processing of a substrate, the quality of the deposited film may be inspected and/or measured. Previously known techniques for inspecting and/or measuring the substrate involve removing the substrate from the processing chamber and placing the substrate in an instrument for inspecting and/or measuring the substrate. Removal of the substrate from the processing chamber may result in gases entering the processing chamber, possibly requiring the processing chamber to be evacuated by a vacuum pump before processing in the chamber (of the substrate or another substrate) can continue.

[0004] To improve throughput of processing chambers and quality of substrates produced, there is a need for a means to inspect and/or measure a substrate undergoing processing in a processing system without removing the substrate from a high-vacuum environment of the processing system.

SUM MARY

[0005] An apparatus for processing a substrate is provided. The apparatus generally comprises a processing chamber body having a first view port and a second view port, a supply for providing process fluid connected with the processing chamber body, a vacuum pump connected with the processing chamber body, a substrate support within the processing chamber body, an electromagnetic radiation emitter operable to illuminate, through the first view port, a substrate on the substrate support, and a detector operable to detect electromagnetic radiation scattered from the substrate through the second view port.

[0006] A system for processing a substrate is provided. The system generally includes a processing chamber having a first slit valve opening configured to permit passage of a substrate therethrough and a second slit valve opening configured to permit passage of a substrate therethrough, a first slit valve operable to open and close the first slit valve opening of the processing chamber, wherein the first slit valve is operable to make an air-tight seal when closed, a second slit valve operable to open and close the second slit valve opening of the processing chamber, wherein the second slit valve is operable to make an air-tight seal when closed, a load-lock having a transfer slit valve opening aligned with the second slit valve opening of the processing chamber, a load-lock port, and a substrate support, and a mechanical arm having an encased probe, wherein the mechanical arm is operable to access the interior of the load-lock via the load-lock port, the mechanical arm is operable to move an instrument within the encased probe into proximity with a substrate on the substrate support, the encased probe has an emitter operable to emit electromagnetic radiation to illuminate the substrate, and the encased probe has a detector operable to detect electromagnetic radiation scattered from the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] So that the manner in which the above recited features of aspects of the present disclosure can be understood in detail, a more particular description of the aspects, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the present disclosure may admit to other equally effective embodiments.

[0008] Figures 1A and 1 B illustrate sectional views of a reduced-pressure processing chamber, according to aspects of the present disclosure.

[0009] Figure 2 illustrates an exemplary processing system, according to certain aspects of the present disclosure.

[0010] Figure 3 illustrates a schematic isometric view of an exemplary load-lock, according to aspects of the present disclosure.

[0011] Figure 4 illustrates a schematic isometric view of a processing chamber, according to aspects of the present disclosure.

[0012] Figure 5 is a set of graphs 500 illustrating monitoring of atomic layer deposition, according to aspects of the present disclosure.

[0013] Figure 6 is a schematic diagram of an exemplary sum frequency generation (SFG) spectroscopy monitoring system configured to measure a substrate during processing, according to aspects of the present disclosure.

[0014] Figure 7 is a schematic diagram of an exemplary substrate handling blade, according to aspects of the present disclosure.

[0015] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized in other embodiments without specific recitation. DETAILED DESCRIPTION

[0016] Methods and apparatuses for measuring layer thickness and layer uniformity of a substrate undergoing processing in a processing system and/or inspecting the substrate to detect defects and/or to perform chemical characterization of layers of the substrate and interfaces between the layers without removing the substrate from a high-vacuum environment of the processing system are provided. The methods and apparatuses enable measurement and/or inspection of a substrate without breaking vacuum of the processing chamber by measuring and/or inspecting the substrate within the processing chamber or within a load-lock chamber connected with the processing chamber.

[0017] One embodiment disclosed herein is a load-lock chamber connected to a processing system. The load-lock chamber has a mechanical arm with an encased probe having one or more instruments that may be used to inspect and/or measure attributes or present of particles on a substrate. The substrate may be removed from the processing chamber and moved into the load-lock, where the one or more instruments inspect and/or measure the substrate. The pressure within the load-lock is maintained at a level similar to the pressure of the processing system or processing chamber, enabling measurement and inspection of the substrate without breaking the vacuum of the processing chamber.

[0018] In another embodiment, a plurality of view ports is arranged on a processing chamber. Lasers, x-ray emitters, and/or other emitters of electromagnetic radiation may illuminate a substrate through a first view port in the processing chamber, and radiation scattered from the substrate may exit the processing chamber through a second view port and be detected, collected, and/or measured by instruments outside of the processing chamber. The substrate may be inspected and/or measured while the substrate is within the processing chamber, without breaking the vacuum of the processing chamber.

[0019] As used herein, radiation that is“scattered” from a substrate refers to radiation that is reflected from the substrate, refracted from the substrate, emitted from the substrate as a result of illumination, and/or transmitted through the substrate. [0020] Semiconductor substrates are processed for a wide variety of applications, including the fabrication of integrated devices and micro devices. As mentioned above, one technique for processing substrates includes exposing the substrate to gases at reduced pressures and causing the gases to deposit a material, such as dielectric material or a conductive metal, on a surface of the substrate. For example, epitaxy is a deposition process that may be used to grow a thin, high-purity layer, frequently of silicon or silicon dioxide, on a surface of a substrate (e.g., a silicon wafer). The material may be deposited in a cross-flow chamber by flowing a process fluid (e.g., a mixture of precursor gases and carrier gases) parallel to, and across, the surface of a substrate positioned on a support, and decomposing (e.g., by heating the process fluid to high temperatures) the process fluid to deposit a material from the process fluid onto the surface of the substrate. Substrates treated according to the above epitaxy techniques may be measured and/or inspected within the processing chamber or in a load-lock, as described in more detail below.

[0021] The disclosed embodiments may be used with techniques for processing substrates that include but are not limited to atomic layer deposition (ALD), chemical vapor deposition (CVD), etching, plasma-enhanced chemical vapor deposition (PECVD), physical vapor deposition (PVD), dielectric deposition, polymer layer deposition, and selective removal processes (SRP).

[0022] Figure 1A illustrates a schematic sectional view of an exemplary processing chamber 100 with components in position for processing, according to aspects of the present disclosure. The processing chamber shown is an epitaxial chamber. The process chamber 100 is used to process (e.g., perform epitaxial deposition on) one or more substrates, including the deposition of a material on an upper surface of a substrate 108. The processing chamber 100 includes an array of radiant heating lamps 102 for heating, among other components, a back side 104 of a substrate support 106 (e.g., a susceptor) disposed within the processing chamber 100. In some embodiments, an array of radiant heating lamps is disposed over the upper dome 128 in addition to the array shown below the lower dome. The substrate support 106 may be a disk-like substrate support 106 with no central opening as shown, or may be a ring-like substrate support.

[0023] Figure 1 B illustrates a schematic side view of the processing chamber 100 taken along line 1 B-1 B in Figure 1A. The liner assembly 163 and the circular shield 167 have been omitted for clarity. The substrate support may be a disk-like substrate support 106 as shown in Figure 1A, or may be a ring-like substrate support 107, which supports the substrate from the edge of the substrate to facilitate exposure of the substrate to the thermal radiation of the lamps 102, as shown in Figure 1 B.

[0024] Referring to Figures 1A and 1 B, the substrate support 106 or 107 is located within the processing chamber 100 between an upper dome 128 and a lower dome 114. The upper dome 128, the lower dome 114, and a base ring 136 that is disposed between the upper dome 128 and lower dome 114 define an internal region of the processing chamber 100. In general, the central portions of the upper dome 128 and of the lower dome 114 are formed from an optically transparent material, such as quartz. The internal region of the processing chamber 100 is generally divided into a process region 156 and a purge region 158.

[0025] The substrate 108 (not to scale) can be brought into the processing chamber 100 through a loading port 103 and positioned on the substrate support 106. The loading port 103 is obscured by the substrate support 106 in Figure 1A, but can be seen in Figure 1 B.

[0026] According to one embodiment, the substrate support 106 is supported by a central shaft 132, which may directly support the substrate support 106 as shown in Figure 1A. According to another embodiment, the central shaft 132 supports a disk like substrate support 107 by means of arms 134, as shown in Figure 1 B.

[0027] According to one embodiment, the processing chamber 100 also comprises a lamphead 145, which supports the array of lamps 102 and cools the lamps 102 during and/or after processing. Each lamp 102 is coupled to an electrical distribution board (not shown), which supplies electricity to each lamp 102.

[0028] According to one embodiment, the processing chamber 100 also includes one or more optical pyrometers 118, which measure temperatures within the processing chamber 100 and on the surface of substrate 108. A controller (not shown) controls electricity distribution from the electrical distribution board to the lamps 102. The controller also controls flows of cooling fluids within the processing chamber 100. The controller controls temperatures within the processing chamber by varying the electrical voltage from the electrical distribution board to the lamps 102 and by varying the flows of cooling fluids.

[0029] A reflector 122 is placed above the upper dome 128 to reflect infrared light radiating from the substrate 108 and upper dome 128 back into the processing chamber 100. The reflector 122 is secured to the upper dome 128 using a clamp ring 130. The reflector 122 has one or more connection ports 126 connected to a cooling fluid source (not shown). The connection ports 126 connect to one or more passages (not shown) within the reflector to allow cooling fluid (e.g., water) to circulate within the reflector 122.

[0030] According to one embodiment, the processing chamber 100 comprises a process fluid inlet 174 connected to a process fluid supply 172. The process fluid inlet 174 is configured to direct process fluid (e.g., trimethyl aluminum (TMA) or silane (SiH₄)) generally across the surface of the substrate 108. The processing chamber also comprises a process fluid outlet 178 located on the side of the processing chamber 100 opposite the process fluid inlet 174. The process fluid outlet 178 is coupled to a vacuum pump 180.

[0031] According to one embodiment, the processing chamber 100 comprises a purge gas inlet 164 formed in the sidewall of the base ring 136. A purge gas source 162 supplies purge gas to the purge gas inlet 164. If the processing chamber 100 comprises a circular shield 167, the circular shield 167 is disposed between the process fluid inlet 174 and the purge gas inlet 164. The process fluid inlet 174, purge gas inlet 164, and process fluid outlet 178 are shown for illustrative purposes, and the position, size, number of fluid inlets and outlets, etc. may be adjusted to facilitate a uniform deposition of material on the substrate 108.

[0032] The substrate support is shown in a position to allow processing of a substrate in the processing chamber 100. The central shaft 132, substrate support 106 or 107, and arms 134 may be lowered by an actuator (not shown). A plurality of lift pins 105 passes through the substrate support 106 or 107. Lowering the substrate support to a loading position below the processing position allows lift pins 105 to contact the lower dome 114, pass through holes in the substrate support 106, and raise the substrate 108 from the substrate support 106. A robot (not shown in Figure 1 , but see robot 208 in Figure 2) then enters the processing chamber 100 to engage and remove the substrate 108 though the loading port 103. The robot that removed the substrate 108 or another robot enters the processing chamber through the loading port 103 and places an unprocessed substrate on the substrate support 106. The substrate support 106 then is raised to the processing position by the actuator to place the unprocessed substrate in position for processing.

[0033] According to one embodiment, processing of a substrate 108 in the processing chamber 100 comprises inserting the substrate through the loading port 103, placing the substrate 108 on the substrate support 106 or 107, raising the substrate support 106 or 107 and substrate 108 to the processing position, heating the substrate 108 using the lamps 102, flowing process fluid 173 across the substrate 108, and rotating the substrate 108. In some cases, the substrate may also be raised or lowered during processing.

[0034] According to some aspects of the present disclosure, epitaxial processing in processing chamber 100 comprises controlling the pressure within the processing chamber 100 to be lower than atmospheric pressure. According to one embodiment, pressure within the processing chamber 100 is reduced to be between approximately 10 torr and 80 torr. According to another embodiment, pressure within the processing chamber 100 is reduced to be between approximately 80 torr and 300 torr. According to one embodiment, the vacuum pump 180 is activated to reduce the pressure of the processing chamber 100 before and/or during processing.

[0035] The process fluid 173 is introduced into the processing chamber 100 from one or more process fluid inlets 174, and exits the processing chamber 100 through one or more process fluid outlets 178. The process fluid 173 deposits one or more materials on the substrate 108 through thermal decomposition, for example, or other reactions. After depositing materials on the substrate 108, effluent (i.e. , waste gases) 166, 175 are formed from the reactions. The effluent 166, 175 exits the processing chamber 100 through the process fluid outlets 178.

[0036] When processing of a substrate 108 is complete, the processing chamber 100 is purged of process fluid 173 and effluent 166, 175 by introducing purge gas 165 (e.g., hydrogen or nitrogen) through the purge gas inlets 164. Purge gas 165 may be introduced through the process fluid inlets 174 instead of, or in addition to, the purge gas inlets 164. The purge gas 165 exits the processing chamber through the process fluid outlets 178.

Exemplary Inline Chamber Metrology

[0037] In embodiments of the present disclosure, a substrate may be processed in a processing chamber and inspected and/or measured without breaking vacuum of the processing chamber. In one embodiment, a load-lock chamber is connected via a valve with a processing chamber. The load-lock has a mechanical arm with an encased probe having one or more instruments that may be used to inspect and/or measure a substrate. The substrate may be removed from the processing chamber and passed through the valve into the load-lock, where the one or more instruments inspect and/or measure the substrate. The pressure within the load-lock is maintained at or lowered to a level similar to the pressure of the processing chamber, enabling measurement and inspection of the substrate without breaking the vacuum of the processing chamber. The substrate may then be returned to the processing chamber for additional processing, with parameters (e.g., temperature or gas-flow rates) of the additional processing determined based on the measuring and inspection that occurred in the load-lock.

[0038] Measurement and inspection techniques that may be used with a load-lock in accordance with aspects of the present disclosure include confocal fluorescence microscopy and imaging; reflection of infrared, ultraviolet, and visible radiation, including ellipsometry; Raman scattering; tip-enhanced Raman scattering; surface plasmon polariton-enhanced Raman scattering; second harmonic; sum frequency spectroscopy; atomic force microscopy (AFM); scanning tunneling microscopy (STM); terahertz or millimeter-wave scanning; and x-ray fluorescence (XRF).

[0039] In another embodiment, a plurality of view ports is arranged on a process chamber. Lasers, x-ray emitters, and/or other emitters of electromagnetic radiation may shine through a first view port onto a substrate in the processing chamber, and radiation scattered (e.g., reflected or refracted) from the substrate may exit the processing chamber through a second view port and be detected, collected, and/or measured by instruments outside of the processing chamber. The substrate may be inspected and/or measured while the substrate is within the processing chamber, without breaking the vacuum of the processing chamber. [0040] Measurement and inspection techniques that may be used with view ports arranged on a processing chamber in accordance with aspects of the present disclosure include confocal fluorescence microscopy and imaging; reflection of infrared, ultraviolet, and visible radiation, including ellipsometry; Raman scattering; second harmonic; sum frequency spectroscopy; terahertz or millimeter-wave scanning; and x-ray fluorescence (XRF).

[0041] Figure 2 is a top view showing an illustrative processing system 200, according to one embodiment of the present disclosure. The processing system 200 includes a load-lock chamber 204, a transfer chamber 206, a handling (e.g., tool and material handling or substrate handling) robot 208 within the transfer chamber 206, a first CVD processing chamber 210, a second CVD processing chamber 212, a control station 214, an ALD processing chamber 216, and a mask chamber 218. The first CVD processing chamber 210, second CVD processing chamber 212, ALD processing chamber 216, and each chamber’s associated hardware are preferably formed from one or more process-compatible materials, such as aluminum, anodized aluminum, nickel plated aluminum, stainless steel, quartz, and combinations and alloys thereof, for example. The first CVD processing chamber 210, second CVD processing chamber 212, and ALD processing chamber 216 may be round, rectangular, or another shape, as required by the shape of the substrate to be coated and other processing requirements.

[0042] The transfer chamber 206 includes slit valve openings 221 , 223, 225, 227, 229 in sidewalls adjacent to the load-lock chamber 204, first CVD processing chamber 210, second CVD processing chamber 212, ALD processing chamber 216, and mask chamber 218. The handling robot 208 is positioned and configured to be capable of inserting a substrate handling blade 209 and/or one or more other tools through each of the slit valve openings 221 , 223, 225, 227, 229 and into the adjacent chamber. That is, the handling robot can insert tools into the load-lock chamber 204, the first CVD processing chamber 210, the second CVD processing chamber 212, the ALD processing chamber 216, and the mask chamber 218 via slit valve openings 221 , 223, 225, 227, 229 in the walls of the transfer chamber 206 adjacent to each of the other chambers. A substrate handling blade, also referred to herein as a“blade,” may be equipped with substrate monitoring equipment, according to aspects of the present disclosure. An example of such a blade is described below with reference to Figure 7. The slit valve openings 221 , 223, 225, 227, 229 are selectively opened and closed with slit valves 220, 222, 224, 226, 228 to allow access to the interiors of the adjacent chambers when a substrate, tool, or other item is to be inserted or removed from one of the adjacent chambers.

[0043] The transfer chamber 206, load-lock chamber 204, first CVD processing chamber 210, second CVD processing chamber 212, ALD processing chamber 216, and mask chamber 218 include one or more apertures (not shown) that are in fluid communication with a vacuum system (e.g., a vacuum pump). The apertures provide an egress for the gases within the various chambers. In some embodiments, the chambers are each connected to a separate and independent vacuum system. In still other embodiments, some of the chambers share a vacuum system, while the other chambers have separate and independent vacuum systems. The vacuum systems can include vacuum pumps (not shown) and throttle valves (not shown) to regulate flows of gases through the various chambers.

[0044] According to aspects of the present disclosure, the first CVD processing chamber 210 may be connected via a valve 215 with a load-lock 211. The load-lock 211 may have a mechanical arm with an encased probe having one or more instruments that may be used to inspect and/or measure a substrate (see Figure 3). The substrate may be removed from the first CVD processing chamber 210 and passed through the valve 215 into the load-lock 211 , where the one or more instruments inspect and/or measure the substrate. The instruments may include one or more of: a confocal fluorescence microscope or imaging system; one or more infrared, ultraviolet, and/or visible light lasers; one or more charge-coupled device (CCD) detectors; one or more mercury cadmium telluride (MCT) detectors; one or more indium gallium arsenide (InGaAs) detectors; a mechanical probe with a tip for tip-enhanced Raman scattering; an atomic force microscope probe; a scanning tunneling microscope probe; a terahertz or millimeter-wave transceiver antenna; and an x-ray emitter and detector. The mechanical arm, encased probe, and instruments are described in more detail with reference to Figure 3 below. The pressure within the load-lock 211 may be lowered to or maintained at a level similar to the pressure of the first CVD processing chamber 210, enabling measurement and inspection of the substrate without breaking the vacuum of the first CVD processing chamber 210. [0045] Similarly, the second CVD processing chamber 212 may be connected via a valve 218 with a load-lock 213, and the ALD processing chamber 216 may be connected via a valve 219 with a load-lock 217. Each of the load-locks 213 and 217 may have a mechanical arm with an encased probe having one or more instruments that may be used to inspect and/or measure a substrate (see Figure 3). As above, a substrate may be removed from the second CVD processing chamber 212 and passed through the valve 218 into the load-lock 213 without breaking the vacuum of the second CVD processing chamber 212. Also as above, a substrate may be removed from the ALD processing chamber 216 and passed through the valve 219 into the load-lock 217 without breaking the vacuum of the ALD processing chamber 216. Once within a load-lock 213 or 217, instruments of the probe may measure and/or inspect the substrate without breaking the vacuum of the second CVD processing chamber 212 or the ALD processing chamber 216.

[0046] Figure 3 illustrates a schematic isometric view of an exemplary load-lock 300, according to aspects of the present disclosure. The load-lock 300 may be an example of the load-locks 211 , 213, and 217, shown in Figure 2. A mechanical arm 302 with an encased probe 304 may access a substrate 306 via a load-lock port 308. The substrate 306 may rest on a substrate support 310 (e.g., a substrate support blade or a pedestal) within the load-lock. The probe may include fiber-optic or metallic cables for conveying electromagnetic radiation (e.g., infrared, ultraviolet, visible laser light, millimeter-wave, or x-rays) from laser sources or other emitters to the substrate. Additionally or alternatively, the probe may include one or more laser sources, terahertz or millimeter-wave transceiver antennas, and x-ray emitters. The probe may also include one or more charge-coupled device (CCD) detectors, mercury cadmium telluride (MCT) detectors, indium gallium arsenide (InGaAs) detectors, a mechanical probe with a tip for tip-enhanced Raman scattering, an atomic force microscope probe, a scanning tunneling microscope probe, an x-ray detector, and/or other types of instruments for measuring and/or inspecting the substrate. The load-lock 300 may also include one or more turbo vacuum ports for evacuating gases (e.g., process fluids that may enter the load-lock from a processing chamber) from the load-lock 300. [0047] Because the mechanical arm 302 is able to bring the probe 304 into close proximity with the substrate, both near-field and far-field inspection techniques are suitable to be performed within the load-lock 300.

[0048] According to aspects of the present disclosure, the probe 304 may be encased in a material (e.g., quartz) that experiences limited out-gassing when exposed to a vacuum, in order to prevent contamination of the substrate from outgassing from materials of the probe (e.g., fiber-optic strands). Instruments that require being in close proximity or contacting the substrate (e.g., a mechanical probe tip for tip-enhanced Raman scattering, an atomic force microscope, or a scanning tunneling microscope) may not be encased in the material that experiences limited out-gassing when exposed to a vacuum. Instead, the instruments that require being in close proximity or contacting the substrate may be constructed of materials that experience limited out-gassing when exposed to a vacuum (e.g., steel).

[0049] Figure 4 illustrates a schematic isometric view of a processing chamber 400 (e.g., an ALD chamber) having a plurality of view ports 402 and 404, according to aspects of the present disclosure. The view ports may be made of quartz or other materials translucent to electromagnetic radiation 424 and 426 (e.g., infrared light, ultraviolet light, visible light, x-rays, and/or millimeter-wave radiation). A first view port 402 may be positioned to allow illumination of the substrate 406 by the electromagnetic radiation to occur at a large grazing angle (i.e. , the angle measured from perpendicular to an upper surface of the substrate). A second view port 404 may be positioned to allow detectors 430 to receive and/or detect electromagnetic radiation 432 scattered from the substrate at an angle similar to the large grazing angle. The processing chamber 400 may be representative of the processing chamber 100 shown in Figures 1A and 1 B. The processing chamber may be connected with a process fluid supply 472 via one or more process fluid inlets 474 and may include a process fluid outlet 478 connected to a vacuum pump 480. The substrate 406 may rest on a substrate support 410 (e.g., a substrate support blade or a pedestal) within the load-lock. The substrate support 410 may be heated, if desirable for performance of the processing chamber.

[0050] One or more lasers (e.g., infrared, ultraviolet, visible spectrum, or x-ray lasers) 420, 422 or other emitters of electromagnetic radiation beams 424, 426 may illuminate the substrate 406 through the view port 402. As illustrated, the lasers may include a femtosecond-picosecond (fs-ps) pulsed visible laser, with a wavelength of 800 nanometers (nm), and an fs-ps pulsed mid-infrared (mid-IR) laser, with a wavelength in the range 1-4 micrometers (pm), but the present disclosure is not so limited, and emitters at other wavelengths may be used. The lasers or other emitters may be mounted to the load lock so that the electromagnetic radiation emitted by the emitters illuminates the substrate at a consistent angle. The mountings of the lasers and other emitters may be moved with one or more actuators (not shown) to cause the radiation to raster across the surface of the substrate in a controlled, reproducible manner during measuring and inspection of the substrate. One or more mirrors 442A and 442B, halfwave plates 444A and 444B, polarizers 446A and 446B, and lenses (e.g., focusing lenses) 448A and 448B may be moved by actuators (not shown) to cause the radiation to raster across the surface of the substrate. Additionally or alternatively, electromagnetic radiation from the emitters may be directed by fiber-optic cables or other conduits, with the cables and/or conduits moved by actuator(s) to cause the radiation to raster across the surface of the substrate.

[0051] Electromagnetic radiation 432 scattered (e.g., reflected or refracted) from the substrate as a result of the illumination of the substrate may exit the processing chamber 400 via the view port 404. One or more apertures 450, collimators 452, polarizers 454, mirrors 456, filters 458, and lenses 460 may direct the electromagnetic radiation 432 to one or more charge-coupled device (CCD) detectors 430, mercury cadmium telluride (MCT) detectors, indium gallium arsenide (InGaAs) detectors, spectrometers, and other types of instruments for measuring and/or inspecting the substrate. The CCD detectors, MCT detectors, InGaAs detectors, spectrometers, and other instruments may detect and/or measure the electromagnetic radiation 432 exiting the view port 404 to determine measurements and other data regarding the substrate. The detectors or other instruments may be mounted to the load lock so that the electromagnetic radiation scattered from the substrate is measured or detected at a consistent angle. The mountings of the detectors and other instruments may be moved with one or more actuators (not shown) to cause the detectors and other instruments to receive radiation scattered from the substrate in response to emitters being rastered across the substrate during measuring and inspection of the substrate. Additionally or alternatively, apertures 450, collimators 452, polarizers 454, mirrors 456, filters 458, and lenses 460 may be moved via actuators to direct the electromagnetic radiation 432 to the detectors and/or instruments.

[0052] The substrate support 410 may move within the processing chamber as part of the measuring and inspecting of the substrate. For example, the substrate support 410 may move the substrate within the processing chamber 400 such that one or more beams 424, 426 entering via the view port 402 are scanned (e.g., rastered) across the surface of substrate. Additionally or alternatively, a scanning galvano mirror may be used to scan beams from the emitters across the surface of the substrate. The galvano mirror may be placed within the processing chamber 400 or located outside of the processing chamber 400.

[0053] While the embodiment shown in Figure 4 shows beams scanning an upper surface of the substrate 406, the present disclosure is not so limited. According to aspects of the present disclosure, the substrate support 410 may have a cut away portion or be translucent to the beams (e.g., a prism), and view ports 402 and 404 may be arranged to allow beams to scan the lower surface of the substrate.

[0054] According to aspects of the present disclosure, second harmonic generation (SHG) and sum frequency generation (SFG) spectroscopy may be used to monitor processed surfaces, such as surfaces deposited via ALD, CVD, PECVD, PVD, dielectric deposition, polymer layer deposition, and SRP. SFG spectroscopy probes second-order molecular hyperpolarizability of a material, which indicates which modes in a non-centrosymmetric media are active. SFG and SHG are second-order nonlinear optical processes in which 2 incoming photons, when spatially and temporally overlapped at the media surface or interface, interact with each other and the surface to generate 1 photon with frequency at the sum of frequencies of the 2 incoming photons. When both the incoming photons are from the same source (and therefore the same frequency), the resulting process is called second harmonic generation (SHG). When both incoming photons are of different frequencies, the resulting optical process is called sum frequency generation (SFG). These second-order optical processes follow conservation of photon energies and momenta. Conservation of photon momenta makes the processes highly directional, and therefore SFG or SHG photons can be spatially separated from incoming photons or other photons from other nonlinear optical processes. SFG and SHG are also highly surface sensitive processes as second-order hyperpolarizabilities are active only in non-centrosymmetric media, for instance at an interface, surface or even for molecules which do not possess a center of symmetry (see, for example, Nature 337(6207): pp. 519-525, 1989). For example, SFG spectroscopy may be used to monitor atomic layer deposition of hydrogen (H₂) on platinum by measuring the intensity of a particular wavenumber associated with the platinum-hydrogen bond, as illustrated with reference to Figure 5, below. SFG spectroscopy may also be used to monitor atomic layer deposition of aluminum oxide/silicon oxide (AIO_c/SiOx) on a silicon substrate by measuring the intensity of a particular wavenumber associated with the AIO_x bond (see, for example, E. Kessels, et al., Journal of Vacuum Science & Technology A 35, 05C313 (2017), available at https://doi.Org/10.1 116.4993597).

[0055] Figure 5 is a graph 500 illustrating curves showing monitoring of atomic layer deposition of hydrogen on platinum in an ALD process in which platinum is exposed to differing flow rates of hydrogen and a sum frequency generation measurement of the surface of the platinum is taken. The curve 510 shows a set of intensities of SFG (measured in s ¹ units) for a set of wavenumbers (measured in cm ¹ units) after an exposure of the platinum to hydrogen at a highest flow rate. After exposure of platinum to the hydrogen at the highest flow rate, SFG spectroscopy shows a relatively high intensity (i.e. , more than 1.1) of the 2020 cm ¹ wavenumber, as shown at point 512. After exposure of the platinum to hydrogen at a lower flow rate, SFG spectroscopy shows a lower intensity (i.e., approximately 0.95) of the 2020 cm ¹ wavenumber, as shown at point 514. After each of the third, fourth, fifth, and sixth exposures of the platinum to hydrogen at successively lower flow rates, SFG spectroscopy shows even lower intensities (i.e., less than 0.90) of the 2020 cm ¹ wavenumber, as shown at points 516, 518, and 520. After exposure of the platinum to hydrogen at the lowest flow rate, SFG spectroscopy shows the lowest intensity (i.e., 0.38) of the 2020 cm ¹ wavenumber, as shown at point 522.

[0056] According to aspects of the present disclosure, the technique of SFG spectroscopy is very specific to surfaces and interfaces, and therefore analysis of data from SFG spectroscopy does not typically require subtraction of background signals from the measured signal. [0057] Figure 6 is a schematic diagram of an exemplary SFG spectroscopy system 600 configured (see, for example, ACS Catalysis, 2014, 4 (6), pp. 1964- 1971) to monitor a substrate 670 (e.g., platinum) during ALD processing, according to aspects of the present disclosure. In the exemplary ALD processing chamber 680, hydrogen flows into the chamber at location 682 and over the substrate, which catalyzes the hydrogen to dissociate and form a layer on the substrate. A mass spectrometer (MS) monitors gases leaving the chamber to gather data on the quantity of hydrogen deposited on the substrate. Heating rods 684 and piston 686 control the temperature and pressure in the ALD chamber. In the exemplary SFG spectroscopy system, a tunable laser system (i.e., one or more electromagnetic radiation emitter(s)) 602 generates a first pulse of laser light 604 with a wavelength in the infrared range (i.e., 1 to 9 micrometers, such as 4 to 7 micrometers, or 5 to 6 micrometers) and a second pulse of laser light 606 with a wavelength in the visible range (i.e., 520 to 900 nanometers, such as 600 to 900 nanometers, 750 to 850 nanometers, or 800 nanometers). The first pulse of laser light then passes through various filters 608 that fine-tune the frequency of the first pulse to a desired frequency. The first pulse is then aimed by a lens 610 to enter a first view port 652 into the processing chamber. The second pulse passes through filters 616 to fine- tune the frequency of the second pulse. A lens 620 aims the second pulse through the first view port 652 into the processing chamber. The first pulse and second pulse may also be aimed via a prism 612 to illuminate the substrate 670. The first pulse and second pulse interact when they illuminate the substrate, generating a second harmonic pulse 630. The second harmonic pulse may be aimed via the prism 612 to exit the processing chamber via a second view port 654. A lens 640 and a filter 642 may aim the second harmonic pulse and filter out reflections of the first pulse and the second pulse, so that a photomultiplier tube (PMT) 632 can collect the second harmonic pulse. The PMT supplies information regarding the second harmonic pulse to a boxcar integrator 634. Finally, the boxcar integrator supplies a signal to a computer 636 for interpretation.

[0058] According to aspects of the present disclosure, the first view port 652 and the second view port 654 may be formed from magnesium fluoride (MgF₂) or calcium fluoride (CaF₂), as those materials allow passage of both the first pulse, having a wavelength in the infrared range, and the second pulse, having a wavelength in the visible range.

[0059] Figure 7 is a schematic diagram of an exemplary substrate handling blade 700, according to aspects of the present disclosure. The exemplary substrate handling blade may include a substrate support blade 702 and an instrument-support arm 704. The instrument support arm may support a laser source 706 (e.g., one or more electromagnetic radiation emitters, lasers, or other sources of laser light, such as a fiber-optic cable delivering laser light from a remote laser) and a spectrometer 708. As illustrated in Figure 6, the laser source may deliver two pulses of laser light 710, 712 having different wavelengths. As shown in Figure 6, the laser source may include one or more mirrors, filters, etalons, and lenses to aim the pulses of laser light at a substrate on the substrate handling blade. The spectrometer may also include one or more irises, filters, lenses, and polarizers to both block the reflections 720 and 722 of the first pulse and second pulse and aim the second harmonic pulse 724 at a detector within the spectrometer.

[0060] According to aspects of the present disclosure, the instrument support arm 704 and substrate handling blade 702 may move together into a processing chamber (e.g., processing chamber 100, shown in Figure 1). Additionally or alternatively, the instrument support arm may move independently of (e.g., be rotated away from) the substrate handling blade when the substrate handling blade enters a processing chamber.

[0061] In aspects of the present disclosure, instruments on the instrument support arm 704, such as laser source 706 and/or spectrometer 708, may perform monitoring of a substrate supported by the substrate handling blade while the substrate handling blade is in a transfer chamber (e.g., transfer chamber 206, shown in Figure 2), allowing monitoring of and/or inspection of a substrate without requiring vacuum to be broken in a processing system.

[0062] According to aspects of the present disclosure, the spectrometer may be a complimentary metal-oxide-semiconductor (CMOS) spectrometer or a photonic crystal fiber (PCF) based spectrometer. [0063] To provide a better understanding of the foregoing discussion, the above non-limiting examples are offered. Although the examples may be directed to specific embodiments, the examples should not be interpreted as limiting the present disclosure in any specific respect.

[0064] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

What is claimed is:

1. An apparatus for processing a substrate, comprising:

a processing chamber body having a first view port and a second view port; a substrate support within the processing chamber body;

an electromagnetic radiation emitter operable to illuminate, through the first view port, the substrate on the substrate support; and

a detector operable to detect electromagnetic radiation scattered from the substrate through the second view port.

2. The apparatus of claim 1 , wherein the substrate support is operable to move the substrate to cause a beam from the electromagnetic radiation emitter to be scanned over a surface of the substrate.

3. The apparatus of claim 1 , further comprising:

a galvano mirror operable to direct a beam from the electromagnetic radiation emitter onto a surface of the substrate.

4. The apparatus of claim 1 , wherein the electromagnetic radiation emitter comprises a first laser source operable to generate a first pulse of laser light having a first wavelength and a second laser source operable to generate a second pulse of laser light having a second wavelength.

5. The apparatus of claim 4, wherein:

the first wavelength is between 1 micrometer and 4 micrometers, inclusive; and

the second wavelength is between 750 nanometers and 850 nanometers, inclusive.

6. The apparatus of claim 4, wherein the detector is operable to measure an intensity of a sum frequency generation (SFG) pulse caused by an interaction between the first pulse, the second pulse, and the substrate.

7. A system for processing a substrate, comprising: a processing chamber having a first slit valve opening configured to permit passage of the substrate therethrough and a second slit valve opening configured to permit passage of the substrate therethrough;

a first slit valve operable to open and close the first slit valve opening of the processing chamber, wherein the first slit valve is operable to make a first air-tight seal when closed;

a second slit valve operable to open and close the second slit valve opening of the processing chamber, wherein the second slit valve is operable to make a second air-tight seal when closed;

a load-lock having a transfer slit valve opening aligned with the second slit valve opening of the processing chamber, a load-lock port, and a substrate support; and

a mechanical arm having an encased probe, wherein:

the mechanical arm is operable to access an interior of the load-lock via the load-lock port;

the mechanical arm is operable to move an instrument within the encased probe into proximity with the substrate on the substrate support; the encased probe has an emitter operable to emit electromagnetic radiation to illuminate the substrate; and

the encased probe has a detector operable to detect electromagnetic radiation scattered from the substrate.

8. The system of claim 7, further comprising a substrate handling robot having a substrate handling blade, wherein:

the mechanical arm is connected with the substrate handling robot; and the mechanical arm is operable to move the instrument within the encased probe into proximity with the substrate on the substrate handling blade.

9. The system of claim 7, wherein the emitter comprises a first laser source operable to generate a first pulse of laser light having a first wavelength and a second laser source operable to generate a second pulse of laser light having a second wavelength.

10. The system of claim 9, wherein: the first wavelength is between 1 micrometer and 4 micrometers, inclusive; and

the second wavelength is between 750 nanometers and 850 nanometers, inclusive.

11. The system of claim 9, wherein the detector is operable to measure an intensity of a sum frequency generation (SFG) pulse caused by an interaction between the first pulse, the second pulse, and the substrate on the substrate support.

12. An apparatus for measuring a substrate in a processing system, comprising: a mechanical arm operable to access an interior of a load-lock of the processing system;

an encased probe on the mechanical arm;

an emitter within the encased probe and operable to emit electromagnetic radiation to illuminate the substrate; and

a detector within the encased probe and operable to detect electromagnetic radiation scattered from the substrate, wherein the mechanical arm is operable to move at least one of the emitter or the detector into proximity with the substrate.

13. The apparatus of claim 12, wherein the emitter comprises a first laser source operable to generate a first pulse of laser light having a first wavelength and a second laser source operable to generate a second pulse of laser light having a second wavelength.

14. The apparatus of claim 13, wherein:

the first wavelength is between 1 micrometer and 4 micrometers, inclusive; and

the second wavelength is between 750 nanometers and 850 nanometers, inclusive.

15. The apparatus of claim 13, wherein the detector is operable to measure an intensity of a sum frequency generation (SFG) pulse caused by an interaction between the first pulse, the second pulse, and the substrate.