Dual pyrometer system for substrate temperature control during film deposition

Abstract

A method of operating a reactor system to provide multi-zone substrate temperature control. The method includes sensing a temperature of a first zone of a substrate supported in the reactor system with a first pyrometer and sensing a temperature of a second zone of the substrate with a second pyrometer. The method also includes comparing the temperatures of the first and second zones to setpoint temperatures for the first and second zones with a controller and, in response, generating control signals to control heating of the substrate. The method also includes controlling operation of a heater assembly operated to heat the substrate based on the control signals.

Description

Technical Field

[0001] This disclosure generally relates to methods and systems for monitoring substrate temperature in semiconductor processing or reactor systems, and more specifically, to methods and apparatus for dual-zone monitoring, and to use in heating control of substrate temperature in semiconductor processing or reactor systems performing epitaxial deposition or growth. Background Technology

[0002] Semiconductor processing, including chemical vapor deposition (CVD), is a well-known process for forming thin films of material on wafers, including silicon wafers. For example, in a CVD process, gaseous molecules of the material to be deposited are provided to the wafer to form a thin film of that material on the wafer through a chemical reaction. This formed film can be polycrystalline, amorphous, or epitaxial. Typically, CVD processes are performed at high temperatures to accelerate the chemical reactions and produce high-quality films, with some processes, such as epitaxial silicon deposition or EPI growth, performed at extremely high temperatures (e.g., above 900°C).

[0003] To achieve the desired temperature, the wafer is heated using resistance heating, induction heating, or radiative heating. Because radiative heating is the most efficient technique, it is currently the preferred method for many deposition processes, including CVD. Radiative heating involves positioning infrared lamps around or within the reaction chamber or reactor; these lamps are typically arranged in a lamp array adjacent to the surface of the wafer on which the material will be deposited. However, one problem with using radiative heating is the tendency to produce uneven temperature distribution or temperature variations along the wafer surface, including thermal spots caused by the use of localized radiative energy or lamps and the resulting focusing and interference effects.

[0004] In a typical CVD process, one or more wafers are placed on a wafer support (or "staple") inside a chamber (or "reaction chamber") within the reactor. Both the wafer and the staple are heated to a desired temperature. In a typical wafer processing step, reactant gases pass through the heated wafer, causing a thin layer of the desired material to be deposited on the wafer surface. If the deposited layer has the same crystal structure as the underlying silicon wafer, it is called an epitaxial or EPI layer (or single-crystal layer, because it has only one crystal structure), and the reaction chamber can be labeled as an epitaxial chamber. Through subsequent processes, these layers are fabricated into integrated circuits.

[0005] To ensure high-quality layers in CVD and other deposition processes, various process parameters must be carefully controlled, with wafer temperature being one of the most critical at each processing step. For example, in CVD, wafer temperature determines the material deposition rate on the wafer, as deposition gases react and deposit onto the wafer at specific temperatures. If the temperature varies across the wafer surface (e.g., temperature uniformity, such as temperature differences), non-uniform film deposition can occur, and the physical properties may be inhomogeneous across the wafer surface. Furthermore, in epitaxial deposition, even slight temperature inhomogeneities can lead to undesirable crystal slip. In the semiconductor industry, since wafers are typically divided into individual chips with integrated circuits on them, it is crucial to deposit materials of uniform thickness and properties on the wafer. If the CVD process or other deposition steps produce non-uniform deposited layers, devices in different areas of the chip may exhibit inconsistent operating characteristics or may fail completely.

[0006] More specifically, in thermal deposition tools or chambers, such as those used for epitaxy, CVD, or atomic layer deposition (ALD), the deposition profile is sensitive to the temperature of the wafer being processed. In channel, NMOS (N-type metal-oxide-semiconductor), and PMOS (P-type metal-oxide-semiconductor) deposition of Si, SiGe, SiP, and SiAs (especially in advanced mode multilayer deposition), tunability, timeliness, and accuracy of the wafer's thermal two-dimensional (2D) profile are required to improve manufacturing yield and throughput.

[0007] Therefore, a method is needed to accurately measure and control wafer temperature, including the temperature at the far edge of the wafer during epitaxial growth and other deposition processes. Summary of the Invention

[0008] This content is provided to introduce some concepts in a simplified form. These concepts are further described in detail in the following description of exemplary embodiments of the disclosure. This content is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0009] The inventors recognized that existing single-region temperature control presents numerous challenges in substrate processing for applications including channel, NMOS, and PMOS. First, existing center-based control can lead to center-to-edge thickness reduction. Due to different substrate types or chip designs, emissivity may vary, resulting in different center-to-edge heat distributions in lamp-heated systems. In particular, the far edges of patterned substrates, which may be highly susceptible to the surrounding thermal environment, can exhibit discontinuities in their heat distribution, potentially one of the most challenging problems in the semiconductor industry. Existing thermocouple-based control cannot directly measure substrate temperature and does not provide substrate edge temperature readings for real-time substrate monitoring and heating feedback control.

[0010] Furthermore, the inventors understand that single-temperature control cannot provide real-time adjustability of center-to-edge temperature or temperature difference useful for film uniformity. For example, because single-zone control only has single-point feedback, profile offset can increase with the number of substrates or layers when operating a large number of substrates or multiple layers on the same substrate. Existing methods for adjusting the center-to-edge substrate profile involve linear lamp power ratio adjustment in an attempt to achieve different power distributions between the top and bottom lamps of the heater assembly. As a result, substrate temperatures at different locations can be adjusted. However, different types of substrates, chip designs, gas flow, and film thickness and dopant distributions vary. For example, center-to-edge thickness shows a significant difference between blanket substrates and patterned substrates. Different center-to-edge temperatures with the same lamp power distribution may be due to different surface emissivity of the substrate and edge heat transfer. These uncertainties lead to challenges in optimizing the lamp power ratio to minimize center-to-edge inhomogeneities on substrates processed in the reactor system.

[0011] According to various embodiments, this document discloses a method for operating a reactor system to provide multi-zone substrate temperature control. The method includes sensing the temperature of a first zone of a substrate supported in the reactor system using a first pyrometer, and sensing the temperature of a second zone of the substrate using a second pyrometer. The method further includes comparing the temperatures of the first and second zones with setpoint temperatures for the first and second zones using a controller, and in response, generating a control signal to control heating of the substrate. The method also includes controlling the operation of a heater assembly configured to heat the substrate based on the control signal.

[0012] In some embodiments of this method, the heater assembly includes multiple heat generators (e.g., elongated filament heater elements, heating lamps (e.g., spotlights), etc.), and control includes mapping a predetermined electrical power to each of the multiple heat generators. In this case, control may also include providing a proportional amount of the predetermined electrical power to each of the multiple heat generators allocated to a first group associated with heating a first region and to each of the multiple heat generators allocated to a second group associated with heating a second region. Furthermore, the method may include repeatedly sensing the temperature of the first region, sensing the temperature of the second region, comparing the temperatures, and controlling the operation of the heater assembly to provide closed-loop control of substrate heating to achieve a setpoint temperature.

[0013] In the same or other embodiments of this method, the first and second pyrometers may each be infrared (IR) pyrometers that sense the temperature of a spot of light on the substrate to detect or determine the temperatures of the first and second regions. In this case, the first region may be a central region of the substrate extending from the center to the outer diameter, and the second region may be an edge region of the substrate extending from the outer diameter of the central region to the edge of the substrate. The spot of light associated with the second pyrometer may have a center point on the substrate at a radial offset of about 1 to about 20 mm from the edge of the wafer. Furthermore, the radial offset from the edge of the substrate may be in the range of about 4 to about 10 mm, and the spot of light monitored by the second pyrometer may have an outer diameter in the range of about 1 to about 15 mm.

[0014] Furthermore, according to various aspects of the specification, a reactor system for providing zone-based substrate temperature control is taught. The system includes a reaction chamber in which a base is provided for supporting a substrate. The system also includes a plurality of heat generators operable to heat the substrate on the base and a temperature monitoring assembly including first and second pyrometers for reading the temperature in a central region and an edge region of the substrate. The reactor system may additionally include a controller that controls a first group of heat generators based on the temperature of the central region and a second group of heat generators, different from the first group, based on the temperature of the edge regions.

[0015] In some embodiments of the system, each heat generator includes a heating lamp, and the controller controls the operation of the heat generators by directing electrical power at first and second levels to the first and second groups of heat generators based on a comparison of the temperatures of the central and edge zones sensed by the first and second pyrometers with predetermined temperature setpoints for the central and edge zones. In this case, the controller can be configured to provide proportional-integral-derivative (PID) control independently to the first and second groups of heat generators based on continuous feedback from the first and second pyrometers.

[0016] In the same or other embodiments of the reactor system, a second pyrometer senses the temperature of a sensor spot on the substrate with an outer diameter ranging from about 1 to about 15 mm. Furthermore, the sensor spot may have an outer diameter ranging from about 4 to about 8 mm, with its center radially offset from the edge of the substrate ranging from about 4 to about 10 mm. In some embodiments, the reactor system includes a reflector, and the second pyrometer is attached to the upper surface of the reflector via a mounting bracket. The reflector may include a transmission channel, and the mounting bracket includes a chamber for receiving a lens tube of the second pyrometer, whereby electromagnetic radiation emitted from the upper surface of the substrate (and / or the developing film on it) is transmitted through the upper wall of the chamber, through the transmission channel, and received at the second pyrometer. Additionally, the chamber may include an aperture through which the emitted electromagnetic radiation is transmitted, the outer diameter of which defines the outer diameter of the sensor spot at the upper surface of the substrate (or the developing film on it).

[0017] In other aspects of this specification, a reactor system is proposed, configured to provide real-time control of substrate temperature variations (e.g., center-to-edge temperature difference control). The system includes multiple heating lamps operable to heat a substrate supported on a pedestal, and temperature monitoring components including a central pyrometer and an edge pyrometer for sensing temperatures in the central region and edge region of the substrate, respectively. Furthermore, the reactor system includes a controller that operates the multiple heating lamps based on comparisons of the temperatures in the central and edge regions with temperature setpoints for the central and edge regions. During operation of the reactor system, the controller generates control signals to independently operate a first group of heating lamps to heat the central region of the substrate and a second group of heating lamps, different from the first group, to heat the edge region of the substrate.

[0018] In some embodiments of the reactor system, control signals are configured to proportionally set the amount of electrical power supplied to the first and second groups of heating lamps, and PID control is applied independently to each of the first and second groups of heating lamps. In these or other embodiments, an edge pyrometer senses or monitors the temperature in its field of view or the temperature of a sensor spot on the substrate with an outer diameter ranging from 1 to 15 mm, and the center of the sensor spot is radially offset from the edge of the substrate ranging from 4 to 10 mm.

[0019] The reactor system may further include a reflector, and an edge pyrometer may be attached to the upper surface of the reflector using a mounting bracket. The reflector may include a transmission channel, and the mounting bracket may include a chamber for receiving a lens tube from the edge pyrometer, whereby electromagnetic radiation emitted from the upper surface of the substrate (or the developing film on the upper surface of the substrate) is guided or transmitted through the upper wall of the chamber to the transmission channel and then to the pyrometer. Furthermore, the reflector may include an aperture through which electromagnetic radiation emitted from the upper surface of the substrate (or the developing film) passes, the outer diameter of which defines the outer diameter of the sensor spot.

[0020] All of these embodiments are within the scope of this disclosure. These and other embodiments will become apparent to those skilled in the art from the following detailed description of certain embodiments with reference to the accompanying drawings, and this disclosure is not limited to any particular embodiment discussed. Attached Figure Description

[0021] Although the specification concludes with claims that are specifically pointed out and clearly claimed as embodiments of this disclosure, the advantages of the embodiments of this disclosure can be more readily determined from the description of certain examples of the embodiments when read in conjunction with the accompanying drawings. In all the drawings, elements with the same element numbers are identical.

[0022] Figure 1This is a simplified top perspective view of a reactor system having a temperature monitoring component for providing dual-zone temperature control, as described in this specification.

[0023] Figure 2 During the operation of the dual-zone temperature monitoring component Figure 1 A top view of the substrate in the reactor system.

[0024] Figure 3 It shows Figure 1 A top view of a portion of the reactor system, showing relative to... Figure 2 The shown substrate and base are chamber heating (or heater) assemblies.

[0025] Figure 4 It shows Figure 3 A bottom view of a portion of the reactor system, showing the useful grouping of heaters into two clusters or groups to control dual-zone heating of the substrate.

[0026] Figure 5 This is a control diagram of the reactor system, including temperature monitoring components and a controller configured to provide dual-zone control of the lamps for the heating (or heater) assembly.

[0027] Figure 6 This is a side view of the center pyrometer and edge pyrometer used in the temperature monitoring assembly of this manual to monitor different spot sizes.

[0028] Figure 7 This is a side cross-sectional view of the edge pyrometer portion of the temperature monitoring assembly, showing its installation to monitor a smaller spot size.

[0029] Figure 8 This is a functional block diagram of the reactor system in this manual.

[0030] Figure 9 It uses dual-zone temperature monitoring to control the reactor system (e.g.) Figure 8 The system's reaction or method of handling indoor temperature. Detailed Implementation

[0031] Although certain embodiments and examples are disclosed below, those skilled in the art will understand that this disclosure extends beyond the specific disclosed embodiments and / or the uses of this disclosure and their obvious modifications and equivalents. Therefore, it is intended that the scope of this disclosure should not be limited to the specific embodiments described herein.

[0032] The illustrations presented herein are not intended to be actual views of any particular material, device, structure, or apparatus, but are merely representations for illustrating embodiments of this disclosure.

[0033] As used herein, the term "substrate" can be used to refer to any one or more underlying materials on which devices, circuits, or films can be formed. A substrate can include a wafer, such as a 300 mm silicon wafer. A substrate can be a blanket substrate or can include a patterned substrate, such as a patterned wafer used to fabricate semiconductor devices.

[0034] As used herein, the term “chemical vapor deposition” can refer to any process in which a substrate is exposed to one or more volatile precursors that react and / or decompose on the substrate surface to produce the desired deposition.

[0035] As used herein, the term "atomic layer deposition" (ALD) can refer to a vapor-phase deposition process in which deposition cycles, preferably multiple consecutive deposition cycles, are performed in a processing chamber. Typically, during each cycle, a precursor is chemisorbed onto the deposition surface (e.g., a substrate surface or a previously deposited lower layer surface, such as material from a previous ALD cycle), forming a monolayer or sub-monolayer that is not readily reactive with the attached precursor (i.e., a self-limiting reaction). Subsequently, if desired, a reactant (e.g., another precursor or a reactive gas) can be introduced into the processing chamber to convert the chemisorbed precursor into the desired material on the deposition surface. Typically, this reactant is capable of further reacting with the precursor. Furthermore, a purging step may also be used during each cycle to remove excess precursor and / or excess reactant and / or reaction byproducts from the processing chamber after the conversion of the chemisorbed precursor. Furthermore, the term “atomic layer deposition” as used herein also means processes specified by related terms such as “chemical vapor deposition,” “atomic layer epitaxy” (ALE), molecular beam epitaxy (MBE), gas source MBE or organometallic MBE, and chemical beam epitaxy when performed with alternating pulses of precursor composition, reactant gas, and purge gas (e.g., inert carrier gas).

[0036] As described in more detail below, the various details and embodiments of this disclosure can be used in conjunction with reaction chambers configured for a variety of deposition processes, including but not limited to ALD, CVD, metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), and physical vapor deposition (PVD). Embodiments of this disclosure can also be used in semiconductor processing systems configured to process substrates with reactive precursors, which may further include etching processes such as reactive ion etching (RIE), capacitively coupled plasma etching (CCP), and electron cyclotron resonance etching (ECR).

[0037] The inventors recognized the importance of real-time sensing and monitoring of the magnitude of temperature changes (e.g., the temperature difference between the center and edge of a substrate) and of using real-time temperature control of the substrate to achieve a desired temperature difference (or limit of variation). A dual-region embodiment can be used to perform sensing and monitoring to limit (or adjust) variations across wafer film thickness, i.e., inhomogeneities within the wafer film thickness. Real-time sensing and monitoring can also (or alternatively) be used to limit interlayer average thickness variations in silicon-germanium / silicon film stacks, such as those used to fabricate finFETs or all-gate semiconductor devices. Furthermore, real-time sensing and monitoring can be used to control the transition thickness (i.e., the rate of change of germanium concentration) in such silicon-germanium / silicon film stacks.

[0038] Real-time sensing and monitoring of temperature changes, and the use of real-time temperature measurements to control heating components, can limit intralayer thickness variations in certain epitaxial deposition operations. For example, for a silicon-germanium layer deposited using real-time temperature measurements obtained using the apparatus and methods of this disclosure, the intralayer thickness non-uniformity can be less than about 1.4%. The average intralayer thickness plus 3σ of the silicon-germanium layer can be about 30% to about 60% (e.g., about 40%) smaller than the average plus 3σ of other identical silicon-germanium layers deposited using indirect temperature sensing and control techniques. For a silicon layer deposited using real-time temperature measurements obtained using the apparatus and methods of this disclosure, the intralayer thickness non-uniformity can be less than about 1.1%. The average intralayer thickness plus 3σ of the silicon layer can be about 30% to about 60% (e.g., about 50%) smaller than the average plus 3σ of other identical silicon layers deposited using indirect temperature sensing and control techniques.

[0039] Real-time sensing and monitoring of temperature changes, and the use of real-time temperature measurements to control heating components, can limit interlayer thickness variations in certain epitaxial film stack deposition operations. For example, in a film stack with alternating silicon-germanium layers and silicon layers, the average interlayer thickness non-uniformity between the silicon-germanium layers forming the film stack can be less than about 0.6% of the average film thickness. The average interlayer thickness non-uniformity between the silicon layers forming the film stack can also be less than about 0.6% of the average film thickness. In view of this disclosure, those skilled in the art will understand that limiting intralayer and interlayer non-uniformity can improve the electrical characteristics of semiconductor devices formed from such film stacks, for example, through limited channel width variations (and thus superior carrier mobility) in finFETs and / or all-gate semiconductor devices formed from film stacks.

[0040] Figure 1A reactor system 100 is shown using a simplified top perspective view, illustrating a portion of components that can be disposed within and adjacent to a reaction chamber configured for epitaxial (EPI) growth or other deposition processes. System 100 is designed to achieve real-time dual-zone substrate temperature control (e.g., utilizing a closed-loop controller design). Within the reaction chamber of system 100, a base 110 is provided for supporting (and typically rotating) a substrate 120. According to this specification, system 100 is configured to provide real-time temperature variation (e.g., center-to-edge difference) control between the substrate center and the edge of substrate 120 to control trans-substrate film thickness variations (e.g., film roll-up or roll-down at the substrate edge) caused by temperature differences during deposition on the upper surface 122 of substrate 120. During deposition, gas streams of precursors, reactants, etc., flow through substrate 120 located within the reaction chamber, as indicated by arrow 130. The precursor may include one or more of the following: (a) a silicon-containing precursor, such as silane; (b) a germanium-containing precursor, such as germanane; (c) a doped precursor, such as an arsenic- or phosphorus-containing dopant; (d) a halide-containing gas, such as hydrochloric acid; and (e) a carrier gas, such as hydrogen. Heating of the substrate 120 may be achieved by a heater assembly (e.g., in…) Figure 3 and 8 Provided (as shown in the figure), the heater assembly includes a group or array of heat generators (upper or top generators (which may be lamps)) disposed below a reflector 140, such as in a lamp array 140 (and a group or array of heat generators (lower or bottom generators (which may be lamps)) spaced at a distance from the upper surface 122 of the substrate 120.

[0041] A temperature monitoring assembly 150 is provided, comprising a chamber pyrometer 152 for measuring the temperature of the upper wall of the chamber (or the temperature of the quartz), and a first zone or central pyrometer 154 and a second zone or edge pyrometer 156. Each of the pyrometers 152, 154, and 156 is supported above a lamp array, for example using a mounting bracket 160 attached to a reflector 140. A heater element radiates heat to a substrate 120 via a base 110. The heated substrate 120 and the developing film on its surface 122 emit electromagnetic radiation. The pyrometers 154 and 156 collect electromagnetic radiation emitted from a portion of the substrate (and / or developing film) within the field of view of the pyrometers 154 and 156. The central pyrometer 154 and the edge pyrometer 156 have a field of view or a corresponding sensor area or spot on the upper surface 122 of the substrate 120 during their operation (or sense or monitor temperature within their field of view or sensor area / spot) as part of sensing or reading the temperature. Each pyrometer has a field of view. In some examples, the field of view of the central pyrometer 154 may be the same size as that of the edge pyrometer 156. In some examples, the field of view of the edge pyrometer 156 may be smaller than that of the central pyrometer 154. This reduces the error in temperature measurements obtained by the edge pyrometer, for example, when the emissivity of the substrate changes relatively rapidly in the radially outward direction. Electromagnetic radiation is collected through the gaps / spaces between linear lamps in the top or upper lamp array, and in most cases, through reflectors 140 before being transmitted through the corresponding mounting brackets 160. In some cases, the emitted electromagnetic radiation passes along an optical path extending between the pyrometer and the upper surface of the wafer, which includes (a) an optical fiber connecting the pyrometer to the mounting (coupler or bracket), (b) an aperture extending through the reflector, (c) the gaps between the heater elements, and (d) the quartz material forming the upper wall of the reaction chamber.

[0042] When the support 160 is included, it is positioned on the reflector 140 such that the spot / sensor regions (i.e., fields of view) of the center and edge pyrometers 154 and 156 are located in two regions of the substrate 120 or its surface 122, or in the center and edge regions. This allows for... Figure 2 As seen in the text, Figure 2 This is a top view of substrate 110 during temperature monitoring operations (and processing in the reaction chamber) of component 150. As shown, the center point of the central pyrometer substrate spot 250 is close to the center of substrate 120, for example, in a radial offset of 1 to 20 mm (or at the radius), with 1 to 10 mm being more preferred (and in one embodiment 9.78 mm is used to accommodate a particular linear lamp array and the gap between adjacent pairs of centrally located lamps). The central spot 250 can be relatively large, for example, its width (e.g., outer diameter (OD)) is in the range of about 10 to about 30 mm, with 20 mm OD used in some embodiments.

[0043] In addition, such as Figure 2 As shown, the center point of the edge pyrometer substrate spot (i.e., field of view) 255 is close to the edge of the substrate 120. It can be within a radial offset or radius of about 20 mm from the edge, for example, about 130 to about 150 mm in the case of a substrate 120 with a radius of 150 mm. Some embodiments place the radial offset or radius within about 10 mm of the substrate edge, and one embodiment places the offset or radius within a range of about 4 to about 9 mm from the substrate edge, for example, about 142 mm on a 150 mm R substrate. The edge pyrometer substrate spot (i.e., field of view) 255 is also preferably smaller than the center pyrometer substrate spot 250. In particular, the spot 255 can have an OD in the range of about 1 to about 15 mm, or more preferably about 1 to about 10 mm, and a useful embodiment provides a spot 255 with an OD in the range of about 4 to about 6 mm (in... Figure 2 (The image shows approximately 5 mm). This smaller spot size provides greater accuracy in temperature readings while offering an acceptable signal-to-noise ratio using existing technology (however, note that smaller spot sizes in the range of approximately 1 to approximately 4 mm may be useful as technology improves).

[0044] In some cases, the field of view of the rim pyrometer can be described relative to the field of view of the central pyrometer. In this respect, (a) the base is supported to rotate about a rotation axis within the reaction chamber; (b) the central pyrometer is arranged along a first optical axis extending through the upper wall of the reaction chamber and intersecting the base; (c) the field of view of the central pyrometer covers the base at a position radially offset from the rotation axis by approximately 0 mm to approximately 10 mm; (d) the rim pyrometer is arranged along a second optical axis, which also extends through the upper wall of the reaction chamber and intersects the base radially outward from the first optical axis; and (e) the field of view of the rim pyrometer also covers the base radially outward from the field of view of the central pyrometer, for example, with a radial offset from the rotation axis of less than approximately 150 mm. The chamber pyrometer may have a field of view radially offset from either or both of the first and second pyrometers and is also configured to acquire the temperature of the upper wall of the reaction chamber using electromagnetic radiation emitted from the upper wall of the chamber, for example, by measuring wavelength intensity in a band different from that measured by the central and rim pyrometers.

[0045] The substrate 120 (or its upper surface 122) can be divided into two (or more) regions, or a central region and an edge region (or first and second regions), using two pyrometers 154 and 156 to measure the substrate temperature. The temperature of these regions is monitored by radially positioning pyrometers in each region, as indicated by sensor areas or light spots 250 and 255. The specific dimensions of each region and the positions of the pyrometers associated with these regions can vary to implement system 100, as long as the light spot / sensor area falls within the associated region. For example, the substrate 120 may have a radius of 150 mm (which may be specified as R150 mm), and the dimensions of these regions may be determined as follows: (a) a central region extending from the center of the substrate to the outer circumference, with a radius ranging from about 130 to about 145 mm; and (b) an edge region extending from the outer circumference of the central region to the edge of the substrate or near the outer circumference.

[0046] Figure 3 A top view of a portion of the reactor system 100 is shown, showing its relative to... Figure 2 The substrate 120 and base 110 are shown with a chamber heating (or heater) assembly 310, and the airflow is as indicated by arrow 130. More specifically, to control the temperature of the substrate 120, the system 100 includes a chamber heating assembly 310 having a bottom or lower row or array 314 and a top or upper row or array 318 of heating lamps. The lamps can take various forms and shapes to implement the system 100, including spotlights and / or linear lamps that can use light-emitting diodes or other technologies to provide light energy or signals. As shown, for example, each of the bottom and top rows 314, 318 includes multiple linear lamps, with 11 shown in each row 314, 318, arranged in spaced-above planes below and above the base 110 and substrate 120. The lamps are arranged in each row / array 234, 238, parallel to each other, with a uniform spacing between adjacent pairs.

[0047] Figure 4 A bottom view of a portion of the reactor system 100 is shown, illustrating the useful grouping of heaters into two clusters or groups to control dual-zone heating of the substrate. Array / row 318 (and Figure 3 The lamps in the bottom or lower array / row 314 can be divided or assigned to control zones and controlled simultaneously as groups / units based on real-time temperature feedback from pyrometers in those physical zones (e.g., pyrometers above lamp rows in the same heating or control zone or with a field of view in each of the two zones).

[0048] In this particular but non-limiting example, the top lamp array 318 (and similarly, the bottom lamp array 314) is divided into two control groups or regions that correspond to the central and edge regions of the substrate 120 (e.g., Figure 2As shown), these are central group 470 (consisting of six central lamps) and edge group 474 (consisting of two pairs of lamps on either side (or opposite side) of central group 470). The number and position of lamps in each control group 470, 474 can vary, and it is generally preferred that the lamps in each group be selected based on the portion or area of ​​the substrate 120 that they heat during operation (e.g., assigning lamps that heat the edges of the substrate 120 to edge control group 474, etc.).

[0049] exist Figure 3 and 4 In this example, system 100 is adapted to provide dual-zone substrate temperature control for an existing lamp bar design with 22 linear lamps. As shown, the linear lamps are divided into two groups (i.e., Figure 4 The center and edge groups 470 and 474, and the lower and upper rows / arrays 314 and 318 of lamps, can be operated using two closed-loop proportional-integral-derivative (PID) controls or other control methods. Two pyrometers 154 and 156 can be used to measure the temperature of the substrate center and edge regions, which are provided as feedback to the controller to activate the power supplies for the two groups 470 and 474.

[0050] Figure 5 A schematic diagram of a reactor system 500 modified to include or implement dual-zone control is shown. As shown, multiple lamps 540 are used to heat a substrate 510, and these lamps can be divided into two zones or two groups for control. A central pyrometer 520 is used to monitor the temperature of the central zone of the substrate 510, while an edge pyrometer 524 is used to monitor the temperature of the edge zones of the substrate 510. The temperature outputs (e.g., sensed or read temperatures or signals corresponding to the temperatures) of the pyrometers 520 and 524 are respectively fed to software or artificial intelligence (AI) modules 532 and 534 of a controller (e.g., a controller for a heating or heater assembly) 530.

[0051] Modules 532 and 534 can be used to compare the sensed or read temperatures from pyrometers 520 and 524 with desired temperature setpoints for the center and edge regions of substrate 510 during a specific process (e.g., epitaxial growth), and these temperature setpoints can be stored in memory accessible to controller 530. Figure 5 (Not shown in the image) The controller 530 typically also includes a processor that executes code or instructions to provide the functionality of the AI ​​modules 532, 534 and the PID modules 533, 535.

[0052] Such a process may take a relatively long time to complete, such as 30 to 90 minutes, and the control provided by controller 530 is preferably performed throughout the entire process (in some cases, including before and after the deposition / growth step). The outputs of AI modules 532, 534 for each zone are provided to PID modules 533 and 535 to adjust the proportion of the total heating lamp electrical power supplied to each zone of lamp 540 by sending control signals to the heater control unit or switch (such as a silicon controlled rectifier (SCR)) to bring the read temperature to the desired setpoint temperature, thereby adjusting each lamp in each zone typically receiving a matched power level.

[0053] System 500 is configured to allow independent dual-zone closed-loop temperature control. Compared to single-zone feedback control, dual-zone pyrometer control increases the independent adjustability of the heat distribution at the substrate center and edge by automatically adjusting the SCR power ratio using AI modules 532, 534 and PID modules 533, 535. Assuming the pyrometer is used as a non-contact, instantaneous sensor to determine the substrate temperature based on the amount of thermal radiation it emits, adjustment of the target edge-to-center heat distribution on the substrate can be achieved directly with a very short transition time, regardless of substrate type, chip design, or environmental influences.

[0054] It is possible Figure 5 The dual-zone control implemented in System 500 of this specification is useful for providing real-time and stable center-to-edge temperature control during film growth (and during other substrate processing in a chamber heated by heating lamps). Examples of films deposited on substrates include: (a) silicon films, (b) silicon-germanium films, and (c) doped silicon films, such as phosphorus-doped and arsenic-doped films. In a steady state, the dual-pyrometer closed-loop control achieves stable temperatures at the substrate center and substrate edge through real-time adjustment of the silicon controlled rectifier (SCR) power. For example, as the film grows, the emissivity of the substrate (e.g., approximately 0.68) and the surrounding environment, including the pedestal edge (e.g., approximately 0.99) and the chamber (e.g., approximately 0.53), varies with deposition.

[0055] Based on a single measurement, the single-zone temperature control mechanism uniformly controls the lamp output power (and associated wafer heating) across the entire wafer. Therefore, the temperature difference between the center and edge portions of the wafer, such as due to emissivity variations on the substrate, is not considered during film deposition. Consequently, the film thickness varies with temperature during deposition onto the wafer. Thus, single-zone control allows observation of temperature shifts between the substrate center and edges. In contrast, utilizing instantaneous and real-time temperature feedback from pyrometers at the substrate center and edges (or within the substrate center and edge regions) minimizes (or at least reduces) thermal transition cycles across the entire substrate, enabling high throughput and repeatability. Using the novel method described herein, film thickness distribution can be controlled by managing any temperature differences between the wafer center portion (and developing film) and the wafer edge portion (and developing film). Other benefits are possible, such as reduced intralayer variations (when needed) and reduced defects (e.g., due to crystal slip), while the novel method is particularly useful for providing the ability to control film thickness distribution across the entire wafer.

[0056] In some embodiments, the temperature monitoring assembly includes a small-spot-size edge pyrometer to measure the substrate temperature at extreme edges (or edge regions). Adding an edge pyrometer to determine the substrate edge temperature provides greater flexibility in pyrometer sensor selection. In some cases, the center and edge pyrometers can be the same, but in some embodiments, it may be useful for the apertures (or apertures in the reflector) within the center and edge mounts to have different sizes, which alters the field of view of the edge and center pyrometers. Compared to conventional pyrometers that can be used to measure the substrate temperature in the center region, the pyrometer selected for the edge pyrometer is chosen to use a small sensing spot to capture and control the temperature at the far edge, which is more easily used to read or sense the edge region temperature required for dual-zone control. Because this spot is smaller than the center spot, for example having an OD of about 5 mm, which is much smaller than the OD of a conventional pyrometer such as about 20 mm, the edge pyrometer can be positioned further away from the center of the substrate and closer to the edge than previously practiced.

[0057] Figure 6 This is a side view of the center pyrometer 610 and the edge pyrometer 630 used in the temperature monitoring assembly of this specification to achieve different spot sizes. In particular, the inventors recognized that the novel edge pyrometer design can be used to reduce the spot size at substrate 604 to enhance far-edge temperature measurement. Far-edge temperature measurement and its temperature control (based on feedback from the far-edge (or edge region) pyrometer to the heater controller) are very useful in controlling the temperature across the entire substrate.

[0058] like Figure 6As shown, the central pyrometer 610 can receive energy from its lens tube 612 to provide a spot size (i.e., field of view) on the substrate 604 in the range of about 15 to about 25 mm, based on its field of view (fov) and working distance, as well as the relative positions of the reflector 620 and the substrate 604. Figure 6 (As shown as an example, approximately 20 mm). The pyrometer receives electromagnetic radiation emitted from the wafer (and developing film) and thereby generates a signal containing information indicating the temperature of the wafer (and developing film) at a radial offset of the edge pyrometer. More specifically, the reflector 620 is positioned equidistant from the outlet of the lens tube 612 and the substrate 604 (or its upper surface), for example, at an operating distance of approximately 250 mm, with the outlet of the tube 612 approximately 125 mm from the reflector 620 and the substrate 604 approximately 125 mm from the reflector 620. This provides the edge pyrometer 610 (and in some cases, the intermediate pyrometer) with a field of view or spot ranging from approximately 15 mm to approximately 25 mm (e.g., approximately 20 mm), which may be located at the center of the substrate 604 or offset slightly from the edge of the substrate to form a central (or intermediate) region.

[0059] For the edge pyrometer 630, a longer tube 632 is used to reduce the working distance, and a field of view or spot size / sensor area with a radius in the range of about 2 to about 10 mm, with a spot having a width (e.g., radius) of about 4 to about 6 mm as an example shown with a width of about 5 mm. Figure 6 The length of the lens tube 632 shown is chosen such that the outlet of the lens tube 632 is closer to the reflector 620 than the tube 612 of the central pyrometer. For example, this separation distance can range from about 25 to about 35 mm, with the shown separation distance being about 30 mm, while maintaining the distance from the reflector to the substrate (e.g., about 125 mm), and this provides a field of view or sensor area / spot with an outer diameter of about 5 mm. Using this edge pyrometer design, the edge pyrometer can be moved (along with its sensor area or spot) to a position closer to the edge of the substrate (e.g., radially offset from the center of the substrate by about 130 to about 150 mm, such as about 142 mm in some examples) for better far-edge temperature control.

[0060] In other embodiments, the working distance is set by lowering the pyrometer 630 within the lamp array to place the tube outlet closer to the reflector 620 and substrate 604. Other embodiments may utilize optical components to achieve a reduced working distance and a smaller spot size, such as... Figure 6 As shown, its outer diameter is approximately 6 millimeters or less.

[0061] Figure 7This is a side cross-sectional view of the edge pyrometer portion of the temperature monitoring assembly, showing a mounting configuration to provide a smaller spot size; an enlarged view is shown at 701. As shown, the pyrometer is mounted to the top surface of reflector 720 using mounting bracket 740, and the pyrometer's lens tube 730 is housed in an inner channel or chamber 742, with its outlet 732 terminating at a distance from the top surface of reflector 720. The energy received is transferred from the top surface of the substrate to the bottom of the chamber / channel 742 via transmission channel 726 in reflector 720. Figure 7 Not shown in the image, but can be found from... Figure 1 (understood in reactor system 100).

[0062] The chamber / channel 742 may have a circular cross-sectional shape, matching the lens tube 730 at the upper part of the receiving tube 730. The outer diameter may be gradually reduced to partially obtain a smaller spot size from the lens tube 730. Figure 7 In the specific embodiment shown, the mounting bracket 740 includes a hole (or chamber outlet) 744 that gradually decreases from the outer diameter / size of the lens tube 730 to the desired spot size or its vicinity (e.g., about 2 to about 10 mm, more preferably about 4 to about 8 mm, and about 6 mm in an exemplary embodiment).

[0063] A bevel 728 can be added to the reflector inlet of the transmission channel 726, and a thread 745 can be added to the hole 744 to provide a small field-of-view (or spot / sensor area size) pyrometer, thereby reducing stray light with minimal hardware risk. This may be ideal for minimizing or controlling stray light or noise that could affect pyrometer readings at the edges of the pyrometer. Most unwanted noise projected onto the sidewall of the pyrometer mounting bracket 740 can be reflected back or absorbed by the mounting bracket 740 instead of entering the pyrometer lens / lens tube 730.

[0064] Figure 8 This is a functional block diagram of a reactor system 800 with dual-zone temperature monitoring and control. The reactor system 800 can take various forms to utilize this monitoring and control, and a reactor chamber 810 with an internal space or volume 812 is shown in a simplified form, providing a base or substrate support 814 that can be rotated via a rotating mechanism 816, as indicated by arrow R. A substrate 820 can be disposed on the base 814, and a film 824 can be deposited or grown during operation of the system 800. For example, the system 800 and chamber 810 can be configured for various deposition processes, including but not limited to ALD, CVD, metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), and physical vapor deposition (PVD).

[0065] An array 830 of heat generators (e.g., heating lamps) 832 is located above chamber 810 and provides heat to base 814 and any substrate 820 and film 824 thereon, which can be controlled by operating heat generators 832 in dual zones (e.g., a central zone or group generator 832 and an edge zone or group generator 832) as indicated by arrows H1 and H2.

[0066] To monitor the temperatures of the substrate 820 and film 824 during operation of the generator 832 in array 830, system 800 includes a dual-zone temperature monitoring assembly 850, comprising a central zone pyrometer 852 and an edge zone pyrometer 854, which sense the temperature of regions or spots of light on the substrate 820 and / or film 824. This monitoring can be achieved by reflecting energy or radiation, as shown by the wavy line passing through the gap in reflector 840 where pyrometers 852 and 854 are mounted.

[0067] A controller 870 is provided in the system for generating control signals (e.g., proportional power output) P. 中心 and P 边缘 The heat generator 832 in the center or first zone is independently controlled based on the sensed temperature of the substrate 820 and / or film 824 during the deposition process. For this purpose, temperature information or pyrometer temperature output T... 中心 and T 边缘 It is transmitted to the controller for processing, and in response, a control output P is generated. 中心 and P 边缘 The controller 870 includes a processor 872 that manages (or is accessible by) the controller 870's memory 874, and software or executable instructions or code 876 that can be executed by the processor to provide the dual-zone temperature monitoring and control functions described herein (e.g., control output P of the array 830 with heat generator 832). 中心 and P 边缘 PID control.

[0068] The controller 870 may also include a user interface 879 for facilitating operator selection among control or program modules 876, interaction with monitored temperature data, modification or updating deposition or processing parameters, etc. For this purpose, the user interface 879 may include a graphical user interface (GUI) generated by the processor 872 based on the GUI generator module 876, which can be displayed on a monitor, touchscreen, etc. A device interface 878 with one or more input / output (I / O) components may be provided in the controller 870 to facilitate wired or wireless communication between the controller 870 and the various heat generators 832 (or their controllers / drivers) of the temperature sensors 852, 874 and / or the array 830.

[0069] Figure 9This refers to a method 900 that uses dual-zone temperature monitoring to control the temperature within the reaction or processing chamber of a reactor system, for example... Figure 8 In system 800, controller 870 uses processor 872 and program module 876 to execute one or more steps of method 900. Method 900 may begin by providing a substrate, such as a substrate having a silicon surface, in a reaction chamber having a dual-zone temperature monitoring assembly as described herein. The reaction chamber can then be used to perform a deposition process to provide a developing film.

[0070] Then, in step 910, method 900 may include receiving electromagnetic radiation using a first or central pyrometer. This radiation is emitted from the substrate, and the central pyrometer is positioned relative to the substrate (and its supports) and the reaction chamber to cover the central portion of the substrate. In step 920, method 900 may include receiving electromagnetic radiation using a second or edge pyrometer. This radiation is also emitted from the substrate, and the second or edge pyrometer is positioned relative to the substrate (and its supports) and the reaction chamber to cover the edge portion of the substrate.

[0071] Method 900 continues with steps 930 and 940, processing the outputs of the center and edge pyrometers to determine the temperature of the center portion of the substrate and the temperature of the edge portion of the substrate using the center and edge pyrometers. Then, in step 950, method 900 includes calculating the temperature difference between the center and edge portions of the substrate using these two determined temperatures. Method 900 then continues in step 960, comparing the temperature difference calculated in step 950 with a predetermined temperature difference (e.g., a temperature difference (or an acceptable range of difference) established through testing or experimentation of the process currently occurring in the reaction chamber and stored in memory, such as memory 874, for access by processor 872). Then, in step 970, method 900 includes increasing or decreasing the electrical power applied to the heater element or heat generator covering the edge portion of the substrate relative to the heater element or heat generator covering the center portion of the substrate when the temperature difference exceeds the predetermined temperature difference (based on the comparison performed in step 960).

[0072] In some examples, method 900 can be used during the deposition of a film stack. The film stack may include alternating layers with different compositions, such as alternating layers of silicon-germanium films and silicon films covering each other. In some examples, the silicon-germanium layer and the silicon layer may be deposited under an isothermal and isobaric temperature mechanism, i.e., the silicon-germanium layer and the silicon layer are deposited at a common deposition temperature and a common pressure, and the aforementioned temperature control system and method are used during the deposition of the silicon-germanium layer and the silicon layer. In view of this disclosure, those skilled in the art will understand that employing an isothermal and isobaric deposition process reduces (or eliminates) the need for settling time between the deposition of subsequent layers.

[0073] According to certain examples, method 900 can be used for non-isothermal and / or non-isobaric deposition processes. For example, during the deposition of silicon-germanium / silicon film stacks, silicon-germanium layers can be deposited using silicon-germanium deposition temperatures between about 550°C and 700°C and / or silicon-germanium deposition pressures between about 5 Torr and about 20 Torr, and silicon layers can be deposited at different temperatures in the range of about 650°C to about 780°C and / or different silicon deposition pressures between about 10 Torr and about 80 Torr. Advantageously, contrary to expectations, due to the use of real-time substrate temperature measurement associated with deposition methods employing indirect temperature measurement, using method 900 requires almost no increase (in some examples, virtually no increase) in stabilization time.

[0074] Benefits, other advantages, and solutions to problems have been described herein with reference to specific embodiments. However, the benefits, advantages, solutions to problems, and any elements that may lead to or make more significant any benefit, advantage, or solution should not be construed as key, essential, or necessary features or elements of this disclosure.

[0075] References to features, advantages, or similar language throughout this specification do not imply that all features and advantages achievable with this disclosure should be included in any single embodiment of the invention. Rather, language relating to features and advantages is to be understood as indicating that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed herein. Therefore, throughout this specification, discussions of features and advantages, as well as similar language, may, but do not necessarily refer to the same embodiment.

[0076] Furthermore, the features, advantages, and characteristics described in this disclosure may be combined in one or more embodiments in any suitable manner. Those skilled in the art will recognize that the subject matter of this application may be practiced without one or more specific features or advantages of a particular embodiment. In other instances, additional features and advantages that may not be present in all embodiments of this disclosure may be recognized in certain embodiments. Furthermore, in some instances, well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring aspects of the subject matter of this disclosure. No claim element is intended to invoke 35U.SC112(f) unless that element is explicitly stated using the phrase “means for…”.

[0077] The scope of this disclosure is limited only by the appended claims, wherein, unless expressly stated, the singular form of an element does not mean "one and only one," but rather "one or more." It should be understood that, unless specifically stated, references to "a," "an," and / or "the" can include one or more, and references to singular items can also include plural items. Furthermore, the term "a plurality of" can be defined as "at least two." As used herein, when used with a list of items, the phrase "at least one of..." means that different combinations of one or more of the listed items may be used, and perhaps only one item from the list is required. The item can be a particular object, thing, or category. Furthermore, where phrases like "at least one of A, B, and C" are used in the claims, the phrase is intended to be interpreted as meaning that A exists alone in one embodiment, B exists alone in one embodiment, C exists alone in one embodiment, or any combination of elements A, B, and C may exist in a single embodiment; for example, A and B, A and C, B and C, or A, B, and C. In some cases, "at least one of Project A, Project B and Project C" can mean, for example, but not limited to, two Project A, one Project B and ten Project C; four Project B and seven Project C; or some other suitable combination.

[0078] All scopes and ratio limits disclosed herein can be combined. Unless otherwise stated, the terms “first,” “second,” etc., are used herein only as labels and are not intended to impose any order, position, or rank requirement on the items referred to by these terms. Furthermore, references to items such as “second” do not require or exclude the existence of items such as “first” or lower numbered, and / or items such as “third” or higher numbered.

[0079] Any references to attachment, fixation, connection, etc., may include permanent, removable, temporary, partial, complete, and / or any other possible attachment options. Furthermore, any reference to non-contact (or similar phrases) may also include reduced contact or minimal contact. Certain terms such as “upper,” “lower,” “upper part,” “lower part,” “horizontal,” “vertical,” “left,” “right,” etc., may be used in the above description. These terms are used where applicable to provide a clear description when dealing with relative relationships. However, these terms do not imply absolute relationships, positions, and / or orientations. For example, for an object, the “upper” surface can simply become the “lower” surface by flipping the object. Nevertheless, it remains the same object.

[0080] Furthermore, instances of one element being "connected" to another element in this specification can include direct and indirect connections. A direct connection can be defined as one element being connected to another element and having some contact with it. An indirect connection can be defined as a connection between two elements that are not in direct contact with each other, but have one or more additional elements between the connected elements. Additionally, as used herein, securing one element to another element can include direct and indirect securing. Furthermore, as used herein, "adjacent" does not necessarily mean contact. For example, one element may be adjacent to another element without contacting it.

[0081] While exemplary embodiments of the present disclosure are illustrated herein, it should be understood that the disclosure is not limited thereto. For example, although reactor systems are described in conjunction with various specific configurations, the disclosure is not necessarily limited to these examples. Various modifications, variations, and enhancements can be made to the systems and methods described herein without departing from the spirit and scope of the disclosure.

[0082] The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of various systems, components and configurations, as well as other features, functions, actions and / or properties disclosed herein, and any and all equivalents thereof.

Claims

1. A reactor system for providing zone-based substrate temperature control, comprising: Reaction chamber; A base used to support the substrate in the reaction chamber; Multiple heat generators, which can be operated to heat a substrate on a base; A temperature monitoring assembly, comprising first and second pyrometers for reading the temperature in the central and edge regions of a substrate; The controller controls a first group of heat generators based on the temperature of the central area, and a second group of heat generators, different from the first group, based on the temperature of the edge area. as well as Reflector The second pyrometer is attached to the upper surface of the reflector via a mounting bracket, wherein the reflector includes a transmission channel, and wherein the mounting bracket includes a chamber for receiving the lens tube of the second pyrometer, thereby guiding the energy received by the second pyrometer through the chamber and the transmission channel to a substrate supported on the base.

2. The reactor system according to claim 1, wherein, Each of the heat generators includes a heating lamp, and the controller controls the operation of the heat generators by directing electrical power at first and second levels to the first and second groups of heat generators based on a comparison of the temperatures of the central and edge regions sensed by the first and second pyrometers with predetermined temperature setpoints for the central and edge regions.

3. The reactor system according to claim 2, wherein, The controller is configured to independently provide proportional-integral-derivative (PID) control to the first and second sets of heat generators based on continuous feedback from the first and second pyrometers.

4. The reactor system according to claim 1, wherein, The second pyrometer monitors the temperature of a sensor spot on a substrate with an outer diameter ranging from 1 to 15 mm.

5. The reactor system according to claim 4, wherein, The sensor spot has an outer diameter in the range of 4 to 8 mm, and its center is located at a radial offset from the edge of the substrate in the range of 4 to 10 mm.

6. A reactor system for providing real-time substrate temperature change control, comprising: Multiple heating lamps, operable to heat a substrate supported on a base; A temperature monitoring component, comprising a central pyrometer and an edge pyrometer, for sensing the temperature in the central region of the substrate and the temperature in the edge region of the substrate, respectively; A controller operates multiple heating lamps based on a comparison of the temperatures of the central and edge regions with temperature setpoints for the central and edge regions. During operation, the controller generates control signals to independently operate a first group of heating lamps to heat the central region of the substrate and a second group of heating lamps, different from the first group, to heat the edge region of the substrate. as well as Reflector The edge pyrometer is attached to the upper surface of the reflector via a mounting bracket, wherein the reflector includes a transmission channel, and wherein the mounting bracket includes a chamber for receiving a lens tube of the edge pyrometer, thereby guiding the energy received by the edge pyrometer through the chamber and the transmission channel to a substrate supported on the base.

7. The reactor system according to claim 6, wherein, The control signal is configured to proportionally set the amount of electrical power supplied to the first and second groups of heating lamps.

8. The reactor system according to claim 7, wherein, PID control is applied independently to each of the first and second groups in the heating lamps.

9. The reactor system according to claim 7, wherein, The edge pyrometer monitors the sensor spot on the substrate with an outer diameter ranging from 1 to 15 mm.

10. The reactor system according to claim 9, wherein, The center of the sensor spot is located radially offset from the edge of the substrate, within the range of 4 to 10 mm.

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