Emission-based temperature measurement of a workpiece in a thermal processing system

Abstract

A heat treatment system for performing heat treatment may include a workpiece support plate configured to support a workpiece and a heat source configured to heat the workpiece. The heat treatment system may include a window having a transparent region and an opaque region, the transparent region being transparent to electromagnetic radiation within a measurement wavelength range, and the opaque region being opaque to electromagnetic radiation within a portion of the measurement wavelength range. A temperature measurement system may include a plurality of infrared emitters and a plurality of infrared sensors, the infrared emitters being configured to emit infrared radiation and the infrared sensors being configured to measure infrared radiation within the measurement wavelength range, wherein the transparent region is at least partially within the field of view of the infrared sensors. A controller may be configured to perform operations including: acquiring transmission and reflection measurements associated with the workpiece, and determining the temperature of the workpiece, the temperature of the workpiece being below about 600°C, based on the measurements.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 983,064, filed February 28, 2020, entitled “Emission-based Temperature Measurement of a Workpiece in a Heat Treatment System,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to heat treatment systems, such as heat treatment systems operable to perform heat treatment on workpieces. Background Technology

[0004] As used herein, a heat treatment chamber refers to a device for heating workpieces, such as semiconductor workpieces (e.g., semiconductor workpieces). Such a device may include a support plate for supporting one or more workpieces and an energy source for heating the workpieces, such as a heating lamp, laser, or other heat source. During heat treatment, the workpieces may be heated under controlled conditions according to the processing mechanism.

[0005] Many heat treatment processes require heating a workpiece within a specific temperature range to allow for various chemical and physical transformations when the workpiece is manufactured into equipment. For example, during rapid heat treatment, a workpiece can be heated to temperatures from approximately 300 °C to approximately 1200 °C by an array of lamps supported by a support plate, typically for a duration of less than a few minutes. In these processes, a primary objective may be to reliably and accurately measure the workpiece's temperature. Summary of the Invention

[0006] Aspects and advantages of embodiments of this disclosure will be set forth in part in the description which follows, or may be learned from the description or by practice of the embodiments.

[0007] One example aspect of this disclosure relates to a heat treatment system for heat-treating a semiconductor workpiece. The heat treatment system may include a workpiece support plate configured to support the workpiece. The heat treatment system may include one or more heat sources configured to heat the workpiece. The heat treatment system may include one or more windows disposed between the workpiece support plate and the one or more heat sources. The one or more windows may include one or more transparent regions and one or more opaque regions, the one or more transparent regions being transparent to at least a portion of electromagnetic radiation within a measurement wavelength range, and the one or more opaque regions being opaque to electromagnetic radiation within that portion of the measurement wavelength range.

[0008] These and other features, aspects, and advantages of the various embodiments will be better understood by referring to the following description and the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the relevant principles. Attached Figure Description

[0009] A detailed discussion of embodiments for those skilled in the art is set forth in the description with reference to the accompanying drawings, wherein:

[0010] Figure 1 An example heat treatment system according to an example aspect of this disclosure is described;

[0011] Figure 2 An example heat treatment system configured to measure the emissivity of a workpiece is described according to an example aspect of this disclosure;

[0012] Figure 3 An example heat treatment system configured to measure the temperature of a workpiece is described according to an example aspect of this disclosure;

[0013] Figure 4 An example temperature measurement system according to an example aspect of this disclosure is described;

[0014] Figure 5A A transmission drawing of material in an example non-transparent area according to an example aspect of this disclosure is depicted.

[0015] Figure 5B An example transmission drawing of a region material according to an example aspect of this disclosure is depicted;

[0016] Figure 6A A transmission drawing of an example workpiece type according to an example aspect of this disclosure is depicted;

[0017] Figure 6B A transmission plot of a normalized workpiece transmission according to an example aspect of this disclosure is depicted.

[0018] Figure 7 A method for measuring the temperature of a workpiece in a heat treatment system according to an exemplary aspect of this disclosure is described; and

[0019] Figure 8 A method for calibrating the reference strength of a sensor in a heat treatment system, according to an example aspect of this disclosure, is described. Detailed Implementation

[0020] Reference will now be made in detail to embodiments, one or more examples of which are illustrated in the accompanying drawings. Each example is provided to explain the embodiments and not to limit the scope of this disclosure. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments without departing from the scope or spirit of this disclosure. For example, features shown or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, various aspects of this disclosure are intended to cover such modifications and variations.

[0021] An exemplary aspect of this disclosure relates to heat treatment systems, such as rapid thermal processing (RTP) systems for workpieces, such as semiconductor workpieces, e.g., silicon workpieces. In particular, an exemplary aspect of this disclosure relates to obtaining temperature measurements that indicate the temperature of at least a portion of the workpiece within the heat treatment system. For example, when a workpiece is heat-treated, the temperature measurement can be used to monitor the temperature of the workpiece.

[0022] The exemplary aspects of this disclosure can be particularly advantageous for obtaining temperature measurements at workpiece temperatures where the workpiece is substantially transmissive and / or does not emit significant blackbody radiation. In some cases, it is difficult to measure the temperature of a workpiece near these temperatures using conventional methods. In particular, some workpieces, such as non-metallized workpieces (e.g., lightly doped silicon workpieces), may be difficult to measure below about 600 °C using conventional methods. For example, the workpiece may be substantially transmissive for many wavelengths typically used for transmission measurements at temperatures below about 600 °C. Furthermore, the workpiece may be too cold to emit practically measurable blackbody radiation at conventional wavelengths.

[0023] Therefore, exemplary aspects of this disclosure can allow for accurate transmission- and emissivity-compensated temperature measurements of workpieces at low temperatures, such as below about 600 °C, and such as from about 400 °C to 600 °C. Furthermore, the sensor used for transmission-based temperature measurements of workpiece temperatures below about 600 °C can be reused and / or can also be used for emission-based workpiece temperature measurements at workpiece temperatures, such as above about 600 °C, where the workpiece is substantially opaque and / or emits significant blackbody radiation. Additionally, the measurement wavelength and / or other process aspects, including phase locking of certain measurements, can be selected to minimize interference between various functions of the heat treatment system. This allows systems and methods according to exemplary aspects of this disclosure to measure temperatures over a wider range, such as a wider range including temperatures below about 600 °C, compared to conventional systems and methods. Furthermore, this allows systems and methods to smoothly transition from transmission-based temperature measurements at temperatures where the workpiece does not emit practically measurable blackbody radiation, e.g., below about 600 °C, to emission-based temperature measurements at temperatures where the workpiece emits measurable radiation, e.g., above about 600 °C), without the need for additional sensors and / or sensor reconfiguration, because, for example, the same sensors used for transmission-based temperature measurements can be used for emission-based temperature measurements once the workpiece is no longer at least partially transparent.

[0024] According to an exemplary aspect of this disclosure, a heat treatment system, such as a rapid heat treatment system, may include a workpiece support plate configured to support a workpiece. For example, the workpiece may be a workpiece to be processed by the heat treatment system, such as a substrate. The workpiece may be or include any suitable workpiece, such as a semiconductor workpiece, such as a silicon workpiece. In some embodiments, the workpiece may be or include a lightly doped silicon workpiece. For example, a lightly doped silicon workpiece may be doped such that the resistivity of the silicon workpiece is greater than about 0.1 Ωcm, such as greater than about 1 Ωcm.

[0025] The workpiece support plate can be or may include any suitable support structure configured to support a workpiece, such as a workpiece configured to support a workpiece within a heat treatment chamber of a heat treatment system. In some embodiments, the workpiece support plate can be configured to support multiple workpieces for simultaneous heat treatment by the heat treatment system. In some embodiments, the workpiece support plate can be or include a rotating workpiece support configured to rotate the workpiece when supported by the rotating workpiece support plate. In some embodiments, the workpiece support plate can be permeable and / or, in addition, configured to allow at least some electromagnetic radiation to pass through the workpiece support plate at least partially. For example, in some embodiments, the material of the workpiece support plate can be selected to allow desired electromagnetic radiation to pass through the workpiece support plate, such as electromagnetic radiation emitted by the workpiece and / or an emitter and / or measured by sensors in the heat treatment system. In some embodiments, the workpiece support plate can be or includes a quartz material.

[0026] According to exemplary aspects of this disclosure, a heat treatment system may include one or more heat sources (e.g., heating lamps) configured to heat a workpiece. For example, one or more heating lamps may emit electromagnetic radiation (e.g., broadband electromagnetic radiation) to heat the workpiece. In some embodiments, one or more heating lamps may be or include, for example, arc lamps, halogen tungsten lamps, and / or any other suitable heating lamps, and / or combinations thereof. In some embodiments, directional elements, such as reflectors (e.g., mirrors), may be configured to direct electromagnetic radiation from one or more heating lamps toward the workpiece and / or a workpiece support plate.

[0027] According to an example aspect of this disclosure, a heat treatment system may include a temperature measurement system configured to measure the temperature of a workpiece within the heat treatment system. For example, the temperature measurement system may include multiple radiation sensors (e.g., infrared sensors) configured to measure electromagnetic radiation at various points within the heat treatment system (e.g., in a heat treatment chamber). Additionally and / or optionally, the temperature measurement system may include multiple radiation emitters (e.g., infrared emitters) configured to emit electromagnetic radiation into the heat treatment system (e.g., a heat treatment chamber) through various components within the heat treatment system, such as the workpiece, chamber windows, workpiece support plates, and / or other suitable components. Based on the radiation emitted by the emitters and / or measured by the sensors, as discussed more specifically below, the temperature measurement system can determine (e.g., estimate) the temperature of the workpiece. For example, as an example of transmission-based temperature measurement, the transmission of a determined portion of the workpiece can be compared with a transmission curve (such as a normalized transmission curve) to determine the temperature of that portion of the workpiece. As an example of emission-based temperature measurement, the temperature can be determined based on the radiation emitted by the workpiece. I wafer The temperature of the workpiece is determined according to the following equation. T :

[0028]

[0029] According to an example aspect of this disclosure, a heat treatment system (e.g., a temperature measurement system) may include a plurality of infrared emitters. The infrared emitters may be configured to emit electromagnetic radiation at one or more infrared wavelengths (e.g., wavelengths from about 700 nanometers to about 1 millimeter). For example, the infrared emitters may emit infrared radiation at least partially directed toward a workpiece. At least a portion of the infrared radiation directed toward the workpiece may be transmitted through the workpiece. Furthermore, at least a portion of the infrared radiation directed toward the workpiece may be reflected by the workpiece. In some embodiments, the infrared emitters may be positioned outside a workpiece processing chamber. For example, an infrared emitter positioned outside the workpiece processing chamber may emit radiation such that the radiation first passes through a chamber sidewall (e.g., a chamber window) before passing through the workpiece. In some embodiments, the infrared emitters may be arranged in a straight line with an array of heating elements (e.g., heating lamps). Additionally and / or alternatively, the infrared emitters may be positioned closer to and / or further away from the workpiece than the heating lamps.

[0030] According to an example aspect of this disclosure, a heat treatment system may include multiple infrared sensors. The infrared sensors may be configured to obtain measurements of electromagnetic radiation (such as electromagnetic radiation having an infrared wavelength) incident on the infrared sensor. In some embodiments, the infrared sensor may be or include a pyrometer. In some embodiments, the pyrometer may be or include a dual-head pyrometer, the dual-head pyrometer including a first head configured to measure a first wavelength of infrared radiation and a second head configured to measure a second wavelength of infrared radiation. In some embodiments, the first wavelength and / or the second wavelength may be within the measurement wavelength range. In some embodiments, the first wavelength may be about 2.3 micrometers and / or the second wavelength may be about 2.7 micrometers.

[0031] According to an exemplary aspect of this disclosure, one or more windows (e.g., chamber windows) may be disposed between the workpiece and / or workpiece support plate and one or more heating lamps. The one or more chamber windows may be configured to selectively block at least a portion of electromagnetic radiation (e.g., broadband radiation) emitted by the one or more heating lamps from entering a portion of the heat treatment chamber (e.g., blocking incident radiation onto the workpiece and / or workpiece support plate and / or one or more sensors). For example, the one or more chamber windows may include one or more opaque regions and / or one or more transmissive regions. As used herein, “opaque” means having a transmittance of less than about 0.4 (40%) for a given wavelength, and “transmissive” means having a transmittance of greater than about 0.4 (40%) for a given wavelength.

[0032] One or more opaque regions and / or one or more transparent regions can be positioned such that the opaque regions block stray radiation of certain wavelengths from the heating lamp, and the transparent regions allow, for example, transmitters and sensors, to freely interact with radiation in the heat treatment chamber at wavelengths blocked by the opaque regions. In this way, the window can effectively shield transmitters and sensors from contamination by the heating lamp while still allowing the heating lamp to heat the workpiece. One or more opaque regions and one or more transparent regions can be generally defined as opaque and transparent for specific wavelengths, respectively; that is, at least for electromagnetic radiation at specific wavelengths, the opaque regions are opaque and the transparent regions are transparent. For example, in some embodiments, the transparent regions may be transparent to at least a portion of electromagnetic radiation within the measurement wavelength range. In some embodiments, the opaque regions may be opaque to at least a portion of electromagnetic radiation within the measurement range. The measurement range may be or include wavelengths at which at least one sensor in the heat treatment system measures the intensity of electromagnetic radiation.

[0033] One or more chamber windows, including one or more opaque regions and / or one or more transmissive regions, can be formed of any suitable material and / or structure. In some embodiments, one or more chamber windows may be or include quartz material. Furthermore, in some embodiments, one or more opaque regions may be or include hydroxyl (OH)-containing quartz, such as hydroxyl-doped quartz (e.g., quartz doped with hydroxyl), and / or one or more transmissive regions may be or include hydroxy-free quartz (e.g., quartz without hydroxyl doping). Advantages of hydroxyl-doped and hydroxy-free quartz can include ease of fabrication. For example, during hydroxyl doping of a monolithic quartz window, hydroxy-free quartz regions can be shielded to create hydroxyl-doped regions (e.g., opaque regions) and hydroxy-free regions (e.g., transmissive regions) within the monolithic window. Furthermore, according to this disclosure, hydroxyl-doped quartz can exhibit desired wavelength blocking properties. For example, hydroxyl-doped quartz can block radiation with a wavelength of about 2.7 micrometers, which may correspond to the measurement wavelengths of some sensors operating in heat treatment systems, while hydroxy-free quartz can be transmissive to radiation with a wavelength of about 2.7 micrometers. Therefore, the hydroxyl-doped quartz region can shield the sensor from stray radiation (e.g., from the heating lamp) in the heat treatment system, and the hydroxyl-free quartz region can be at least partially disposed within the sensor's field of view (e.g., the region where the sensor is configured to measure infrared radiation) to allow the sensor to obtain measurements within the heat treatment system. Furthermore, the hydroxyl-doped quartz can be partially opaque to radiation with a wavelength of about 2.3 micrometers (e.g., with a transmittance of about 0.6 or 60%), which can at least partially reduce contamination from stray radiation (e.g., from the heating lamp) in the heat treatment system.

[0034] Infrared radiation emitted by an infrared emitter and / or measured by an infrared sensor may have one or more associated wavelengths. For example, in some embodiments, the infrared emitter may be or include a narrowband infrared emitter that emits radiation such that the wavelength range of the emitted radiation is within a numerical tolerance (e.g., within 10% of the numerical value), in which case the emitter is used with reference to the aforementioned numerical value. In some embodiments, this can be achieved by a combination of a broadband emitter emitting a broadband spectrum (e.g., a Planck spectrum) and an optical filter (such as an optical notch filter), the optical filter being configured to pass only through a narrowband within the broadband spectrum. Similarly, an infrared sensor may be configured to measure the intensity of narrowband infrared radiation at a numerical value (e.g., within its tolerance). For example, in some embodiments, an infrared sensor (such as a pyrometer) may include one or more heads configured to measure (e.g., selectively measure) a specific narrowband wavelength.

[0035] In some embodiments, the infrared radiation emitted by the infrared emitter and / or measured by the infrared sensor can be within a measurement wavelength range, which may be or include a continuous range and / or a discontinuous range. The measurement wavelength range can be selected based on the characteristics of the workpiece and / or the workpiece handling system. For example, the measurement wavelength range may include wavelengths that are transparent to at least about 600°C in the transparent areas of one or more chamber windows. Additionally and / or optionally, the measurement wavelength range may include wavelengths that are opaque to at least about 600°C in the opaque areas of one or more chamber windows. In this way, the emitter can emit radiation that substantially transmits through the transparent areas and is at least partially protected from heating lamp contamination by the opaque areas before incident on the sensor. Although it may be desirable in some embodiments to eliminate contamination from the heating lamp within the measurement wavelength range, the measurement wavelength range may still include wavelengths with contamination from the heating lamp (e.g., wavelengths that can at least partially pass through the opaque areas). Additionally and / or optionally, the measurement wavelength range may include wavelengths at which the workpiece emits significant (e.g., measurable) blackbody radiation, at least at temperatures above about 600 °C. In some embodiments, the measurement wavelength range may include about 2.3 micrometers and / or about 2.7 micrometers. For example, in some embodiments, one or more infrared sensors may be configured to measure the intensity of infrared radiation at about 2.3 micrometers in the sensor's field of view. Similarly, one or more infrared sensors may be configured to measure the intensity of infrared radiation at about 2.7 micrometers in the sensor's field of view.

[0036] In some embodiments, the temperature measurement system may include an emissivity measurement system configured to measure (e.g., estimate) the emissivity of a workpiece. As an example of measuring the emissivity of a workpiece, the emissivity measurement system may include an infrared emitter configured to emit infrared radiation directed toward the workpiece. In some embodiments, the infrared emitter may emit infrared radiation directed at an oblique angle toward the surface of the workpiece (e.g., at an angle less than 90 degrees to the surface of the workpiece). In this way, the transmissive portion of the emitted radiation can be transmitted through the workpiece, and the reflective portion of the emitted radiation can be reflected by the surface of the workpiece. The reflection angle of the reflective portion can be predicted and / or known based on the characteristics of the workpiece. An infrared sensor may be positioned to measure the transmissive and / or reflective portions. The emissivity measurement system may determine the emissivity of the workpiece at least in part based on the first and / or second portions. In some embodiments, the emissivity measurement system, such as the emitter and / or sensor, may operate at a first wavelength in the measurement wavelength range. For example, the first wavelength may be a wavelength at which the transmissive region of a chamber window is transmissive and / or the opaque region is opaque. In some embodiments, the first wavelength may be or include about 2.7 micrometers.

[0037] Additionally and / or optionally, the heat treatment system (e.g., a temperature measurement system) may include a transmission measurement system. The transmission measurement system may be configured to obtain one or more transmission measurements of the workpiece. For example, in some embodiments, the transmission measurement system may obtain a center transmission measurement (e.g., via a center sensor, such as a center pyrometer) of the central portion of the workpiece and an edge transmission measurement (e.g., via an edge sensor, such as an edge pyrometer) of the edge portions of the workpiece. In some embodiments, the transmission measurement system may include one or more infrared emitters configured to emit infrared radiation perpendicularly oriented to the surface of the workpiece. Furthermore, the transmission measurement system may include one or more infrared sensors disposed opposite to one or more infrared emitters and configured to measure a portion of the infrared radiation emitted by the one or more infrared emitters and passing through the workpiece.

[0038] The temperature of a workpiece can be determined based on its transmission. However, the transmission of a workpiece is not solely related to temperature. For example, workpiece characteristics, such as bulk doping levels, surface reflectivity, and thickness, all affect transmission. Therefore, in some embodiments, the temperature measurement system can determine a normalized transmission measurement related to the workpiece temperature. For example, the normalized transmission measurement can range from 0 to 1, regardless of workpiece characteristics.

[0039] Additionally and / or optionally, sensor measurements used to determine the transmission of the workpiece may be affected by other components in the chamber (such as, for example, workpiece support plates, chamber windows, and / or any other components), and especially by components that must be emitted by the transmitter and measured by the sensor. According to an exemplary aspect of this disclosure, a heat treatment system (e.g., a temperature measurement system) can determine a reference intensity for each of one or more sensors in the heat treatment system, denoted herein as... I 0 When the workpiece is not present in the processing chamber, the reference intensity can correspond to the radiation emitted by the emitter and / or incident on the sensor. In other words, the reference intensity can only be reduced from the intensity of the radiation emitted by the emitter by the contribution of components other than the workpiece in the heat treatment system. This can also correspond to the case where the workpiece is 100% transmitted. In some embodiments, the reference intensity can be measured before the workpiece is inserted into the processing chamber, for example, between heat treatments of two workpieces.

[0040] In some embodiments, the transmission measurement system may operate at the same wavelength as the emissivity measurement system (e.g., a first wavelength). Additionally and / or optionally, the transmission measurement system may operate at a second wavelength different from the first wavelength. For example, in some embodiments, the second wavelength may be a wavelength in which one or more opaque regions of the chamber window, while opaque to the first wavelength, are not opaque to the second wavelength, such that radiation at the first wavelength is blocked by the opaque regions, and at least partially allows radiation at the second wavelength to pass through the opaque regions. For example, the transmission of the opaque regions at the second wavelength may be greater than the transmission at the first wavelength. In some embodiments, the second wavelength may be 2.3 micrometers.

[0041] In some cases, a transmission measurement system not fully shielded by the chamber window may require and / or necessitate the use of a second wavelength. For example, space considerations, interference considerations, and / or other factors may render the heat treatment system undesirable at the first wavelength. As an example, while an emissivity measurement system may include transmission measurements for determining emissivity, which may be correlated with the workpiece temperature, it may sometimes be desirable to obtain temperature measurements in multiple regions of the workpiece. For example, obtaining temperature measurements in multiple regions (such as the central portion and / or edge portions) can allow for improved monitoring of process uniformity. However, additional sensors may be required to obtain temperature measurements in multiple regions. Furthermore, transmission measurements may require the transmitter to be positioned opposite the additional sensors, and in some cases, it may be necessary to position the transmission area within the transmitter's field of view so that the transmission measurement functions at the first wavelength. However, in some embodiments, these additional sensors may be used for emission measurements in addition to transmission measurements, according to exemplary aspects of this disclosure. In some cases, these transmission areas may cause contamination from the heating lamp in the measurements of the additional sensors, especially when the sensors are used for emission measurements. Therefore, while one approach to this problem is to configure an additional transmission area for the chamber, other solutions are also possible, including phase locking of emission and / or sensor measurements, which will be discussed in more detail below.

[0042] In some embodiments, multiple infrared emitters and / or multiple infrared sensors can be phase-locked. For example, in some embodiments, radiation emitted by one or more emitters can be pulsed at a pulse frequency. The pulse frequency can be selected to be or include frequencies with little or no radiation component in the heat treatment system. For example, in some embodiments, the pulse frequency can be approximately 130 Hz. In some embodiments, a pulse frequency of 130 Hz can be particularly advantageous because the heating lamp may substantially not emit radiation at a frequency of 130 Hz. As an example of pulsed radiation from one or more emitters, a chopper wheel with one or more slits can be rotated within the field of view of one or more emitters, such that a continuous stream of radiation from one or more emitters is intermittently allowed to pass through the chopper wheel at a pulse frequency. Thus, a continuous stream of radiation can be converted into a pulsed stream of radiation at a pulse frequency by rotation of the chopper wheel.

[0043] Additionally and / or optionally, one or more sensors can be phase-locked based on the pulse frequency. For example, a transmission measurement system can be configured to isolate measurements from sensors based on the pulse frequency. As an example, a transmission measurement system can compare measurements at the pulse frequency with measurements not at the pulse frequency, such as by subtracting the measurement immediately preceding the measurement performed at the pulse frequency, to isolate the signal contribution from the component at the pulse frequency from the interference component. In other words, sensor measurements not phase-locked to the pulse frequency (e.g., obtained at the same or higher frequency as the pulse frequency and / or obtained out of phase with the phase-locked measurement) can indicate only stray radiation in the chamber, and / or sensor measurements phase-locked to the pulse frequency can indicate the sum of stray radiation and emitted radiation from the transmitter. Thus, emitted radiation can be separated by subtracting a known amount of stray radiation from the unphase-locked measurement. As an example, if the pulse frequency is 130 Hz, the sensor can obtain measurements at 260 Hz or higher, such that one or more stray intensity measurements are associated with each phase-locked measurement. In this way, the transmission measurement system can reduce interference from stray radiation (e.g., stray light) in sensor measurements.

[0044] The systems and methods according to exemplary aspects of this disclosure can provide several technical effects and benefits related to the heat treatment of workpieces. As an example, the systems and methods according to exemplary aspects of this disclosure can provide accurate temperature measurements at a workpiece temperature at which the workpiece is substantially transmissive and / or does not emit significant blackbody radiation. For example, the systems and methods according to exemplary aspects of this disclosure can allow accurate temperature measurements below approximately 600 °C, regardless of the workpiece composition.

[0045] Another technical effect of this disclosure is an improvement in temperature measurement range. For example, a system according to an example aspect of this disclosure can allow for accurate temperature measurements of workpieces at low temperatures (such as below about 600 °C, or from about 400 °C to 600 °C) based on transmittance and emissivity compensation. Furthermore, a sensor used for a transmittance-based temperature measurement of a workpiece temperature below about 600 °C can be reused and / or also used for an emissivity-based temperature measurement of the workpiece temperature, where the workpiece is substantially opaque and / or emits significant blackbody radiation, such as above about 600 °C. Additionally, the measurement wavelength and / or other process aspects, including phase locking of certain measurements, can be selected to minimize interference between various functions of the heat treatment system. This allows systems and methods according to an example aspect of this disclosure to measure temperatures over a wider range, such as a wider range including temperatures below about 600 °C, compared to conventional systems and methods. Furthermore, this allows systems and methods to smoothly transition from transmission-based temperature measurements at temperatures where the workpiece does not emit practically measurable blackbody radiation, e.g., below about 600°C, to emission-based temperature measurements at temperatures where the workpiece emits measurable radiation, e.g., above about 600°C, without the need for additional sensors and / or sensor reconfiguration, because, for example, the same sensors used for transmission-based temperature measurements can be used for emission-based temperature measurements once the workpiece is no longer at least partially transparent.

[0046] Variations and modifications may be made to these exemplary embodiments of the present disclosure. The singular forms “a,” “and,” and “the” as used in the specification include plural references unless the context clearly specifies otherwise. The use of “first,” “second,” “third,” etc., is as an identifier and does not necessarily indicate any order, implication, or otherwise. For purposes of illustration and discussion, exemplary aspects may be discussed with reference to “substrate,” “workpiece,” or “processed part.” Those skilled in the art using the disclosure provided herein will understand that exemplary aspects of this disclosure can be used for any suitable workpiece. The term “about” used in conjunction with numerical values ​​means within 20% of the specified value.

[0047] Exemplary embodiments of this disclosure will now be discussed in detail with reference to the accompanying drawings. Figure 1An example Rapid Thermal Processing (RTP) system 100 according to an exemplary embodiment of the present disclosure is depicted. As shown, the RTP system 100 includes an RTP chamber 105, which includes a top 101 and a bottom 102, windows 106, 108, a workpiece 110, a workpiece support plate 120, heat sources 130, 140 (e.g., heating lamps), infrared emitters 150, 152, 154, sensors 165, 166, 167, 168 (e.g., pyrometers, such as dual-head pyrometers), a controller 175, a sidewall / door 180, and an airflow controller 185.

[0048] Workpiece support plate 120 supports the workpiece 110 to be processed within RTP chamber 105 (e.g., a quartz RTP chamber). Workpiece support plate 120 may be a workpiece support operable to support workpiece 110 during heat treatment. Workpiece 110 may be or include any suitable workpiece, such as a semiconductor workpiece, such as a silicon workpiece. In some embodiments, workpiece 110 may be or include a lightly doped silicon workpiece, for example, the lightly doped silicon workpiece may be doped such that the resistivity of the silicon workpiece is greater than about 0.1 Ωcm, for example, greater than about 1 Ωcm.

[0049] The workpiece support plate 120 may be or include any suitable support structure configured to support the workpiece 110, for example, configured to support the workpiece 110 within the RTP chamber 105. In some embodiments, the workpiece support plate 120 may be configured to support multiple workpieces 110 for simultaneous heat treatment by a heat treatment system. In some embodiments, the workpiece support plate 120 may rotate the workpiece 110 before, during, and / or after heat treatment. In some embodiments, the workpiece support plate 120 may be permeable and / or, in addition, configured to allow at least some electromagnetic radiation to pass through the workpiece support plate 120 at least partially. For example, in some embodiments, the material of the workpiece support plate 120 may be selected to allow desired electromagnetic radiation to pass through the workpiece support plate 120, for example, electromagnetic radiation emitted by the workpiece 110 and / or emitters 150, 152, 154. In some embodiments, the workpiece support plate 120 may be or include a quartz material, such as a hydroxyl-free quartz material.

[0050] The workpiece support plate 120 may include at least one support pin 115 extending from the workpiece support plate 120. In some embodiments, the workpiece support plate 120 may be spaced apart from the top plate 116. In some embodiments, the support pin 115 and / or the workpiece support plate 120 may transfer heat from the heat source 140 and / or absorb heat from the workpiece 110. In some embodiments, the support pin 115, the protective ring 109, and the top plate 116 may be made of quartz.

[0051] A protective ring 109 can be used to reduce edge effects of radiation from one or more edges of the workpiece 110. A sidewall / door 180 allows the workpiece 110 to enter and seals the chamber 105 when closed, allowing the workpiece 110 to be heat-treated. For example, process gases can be introduced into the RTP chamber 105. Two rows of heat sources 130, 140 (e.g., lamps or other suitable heat sources) operable to heat the workpiece 110 in the RTP chamber 105 are displayed on either side of the workpiece 110. As described more specifically below, windows 106, 108 can be configured to block at least a portion of the radiation emitted by the heat sources 130, 140.

[0052] RTP system 100 may include heat sources 130, 140. In some embodiments, heat sources 130, 140 may include one or more heating lamps. For example, heat sources 130, 140 including one or more heating lamps may emit electromagnetic radiation (e.g., broadband electromagnetic radiation) to heat workpiece 110. In some embodiments, for example, heat sources 130, 140 may be or include arc lamps, halogen lamps, and / or any other suitable heating lamps and / or combinations thereof. In some embodiments, directional elements (not depicted), such as reflectors (e.g., mirrors), may be configured to direct electromagnetic radiation from heat sources 130, 140 into RTP chamber 105.

[0053] According to an exemplary aspect of this disclosure, windows 106, 108 may be disposed between workpiece 110 and heat sources 130, 140. Windows 106, 108 may be configured to selectively block at least a portion of electromagnetic radiation (e.g., broadband radiation) emitted by heat sources 130, 140 from entering a portion of the rapid heat treatment chamber 105. For example, windows 106, 108 may include an opaque region 160 and / or a transmissive region 161. As used herein, "opaque" means having a transmittance of substantially less than about 0.4 (40%) for a given wavelength, and "transmissive" means having a transmittance of substantially greater than about 0.4 (40%) for a given wavelength.

[0054] The opaque region 160 and / or the transparent region 161 can be positioned such that the opaque region 160 blocks stray radiation of certain wavelengths from heat sources 130, 140, while the transparent region 161 allows, for example, transmitters 150, 152, 154 and / or sensors 165, 166, 167, 168 to freely interact with radiation in the RTP chamber 105 at wavelengths blocked by the opaque region 160. Thus, windows 106, 108 can effectively shield the RTP chamber 105 from contamination by heat sources 130, 140 at a given wavelength, while still allowing heat sources 130, 140 to heat workpiece 110. For a specific wavelength, the opaque region 160 and the transparent region 161 can be broadly defined as opaque and transparent, respectively; that is, at least for electromagnetic radiation at a specific wavelength, the opaque region 160 is opaque, while the transparent region 161 is transparent.

[0055] The chamber windows 106, 108, including the opaque region 160 and / or the permeable region 161, can be formed of any suitable material and / or structure. In some embodiments, the chamber windows 106, 108 may be or include quartz material. Furthermore, in some embodiments, the opaque region 160 may be or include hydroxyl (OH)-containing quartz, such as hydroxyl-doped quartz (e.g., quartz doped with hydroxyl), and / or the permeable region 161 may be or include hydroxyl-free quartz (e.g., quartz without hydroxyl doping). The advantages of hydroxyl-doped and hydroxyl-free quartz can include ease of fabrication. For example, during hydroxyl doping of a monolithic quartz window, the hydroxyl-free quartz region can be shielded to create hydroxyl-doped regions (e.g., opaque regions) and hydroxyl-free regions (e.g., permeable regions) within the monolithic window. Furthermore, according to this disclosure, hydroxyl-doped quartz can exhibit desired wavelength blocking properties. For example, hydroxyl-doped quartz can block radiation with a wavelength of about 2.7 micrometers, which corresponds to the measurement wavelengths of some sensors (e.g., sensors 165, 166, 167, 168) operating in the heat treatment system 100, while hydroxyl-free quartz is transparent to radiation with a wavelength of about 2.7 micrometers. Therefore, the hydroxyl-doped quartz region can shield the sensors (e.g., sensors 165, 166, 167, 168) from stray radiation (e.g., from heat sources 130, 140) in the rapid heat treatment chamber 105, and the hydroxyl-free quartz region can be at least partially positioned within the sensor's field of view to allow the sensor to obtain measurements within the heat treatment system. Furthermore, hydroxyl-doped quartz can be partially opaque to radiation with a wavelength of about 2.3 micrometers (e.g., with about 0.6 or 60% transmittance), which can at least partially reduce contamination from stray radiation (e.g., from heat sources 130, 140) in the rapid heat treatment system 100.

[0056] Gas controller 185 can control the airflow through RTP system 100, which may include inert and / or reactive gases, such as oxygen or nitrogen, that do not react with workpiece 110, and reactive gases that react with the material of workpiece 110 (e.g., semiconductor workpiece, etc.) to form a layer on workpiece 110. In some embodiments, an electric current may flow through the atmosphere in RTP system 100 to generate ions that react with or on the surface of workpiece 110, and additional energy may be applied to the surface by bombarding the surface with high-energy ions.

[0057] Controller 175 controls various components within the RTP chamber to guide the heat treatment of workpiece 110. For example, controller 175 may be used to control heat sources 130 and 140. Additionally and / or optionally, controller 175 may be used to control airflow controller 185, door 180, and / or temperature measurement systems, including, for example, transmitters 150, 152, 154, and / or sensors 165, 166, 167, 168. Controller 175 may be configured to measure the temperature of the workpiece, which will be discussed more specifically with reference to the accompanying drawings. For example, Figure 2 A heat treatment system 200 is depicted, which includes one or more components of a heat treatment system 100, the heat treatment system 100 being configured to perform in-situ emissivity determination of a workpiece. Figure 3 At least one heat treatment system 300 is depicted, comprising one or more components of a heat treatment system 100, which is configured to perform transmission-based and / or emission-based temperature measurements of a workpiece. Similarly, Figure 4 A temperature measurement system 400 is depicted, which includes one or more components of a heat treatment system 100, the heat treatment system 100 being configured to perform transmission-based and / or emission-based temperature measurements of a workpiece.

[0058] As used herein, a controller, control system, or similar system may include one or more processors and one or more memory devices. One or more processors may be configured to execute computer-readable instructions stored in one or more memory devices to perform operations, such as any operations for controlling the heat treatment system described herein.

[0059] For the purposes of explanation and discussion, Figure 1 An example heat treatment system 100 is depicted. Those skilled in the art who use the disclosure provided herein will understand that various aspects of this disclosure can be used with other heat treatment systems for workpieces without departing from the scope of this disclosure.

[0060] For the purposes of explanation and discussion, Figure 2 An example heat treatment system 200 is depicted. Specifically, the heat treatment system includes, as shown in reference... Figure 1 The heat treatment system 100 discussed includes one or more components. Specifically, Figure 2 At least the components used to determine the in-situ emissivity measurement of workpiece 110 are depicted, including at least an emitter 150 and sensors 165 and 166. Figure 2 As shown, emitter 150 can be configured to emit infrared radiation directed at an oblique angle to workpiece 110. The transmissive portion of the emitted radiation emitted by emitter 150 is transmitted through workpiece 110 and incident on transmission sensor 165. The reflective portion of the emitted radiation emitted by emitter 150 is reflected by workpiece 110 and incident on reflection sensor 166. The emissivity of the workpiece can be determined from the transmissive and emitting portions. For example, the transmission of workpiece 110 can be represented by the intensity of the radiation incident on transmission sensor 165. Furthermore, the reflection of workpiece 110 can be represented by the intensity of the radiation incident on reflection sensor 166. Based on transmission and reflection, the transmittance τ and reflectance ρ can be determined as the transmission and reflection values ​​relative to a reference intensity, respectively. I 0 The ratio of the reference intensity to the intensity at sensors 165 and 166, when no workpiece is present in the heat treatment system 200, can be used to represent the intensity at these sensors. Therefore, the emissivity ε can be calculated as:

[0061]

[0062] According to an exemplary aspect of this disclosure, one or more transmission regions 161 may be at least partially disposed within the field of view of the transmitter 150 and / or sensors 165, 166. For example, the transmitter 150 and / or sensors 165, 166 may operate within a measurement wavelength range, and the transmission regions 161 are transparent to that measurement wavelength range. For example, in some embodiments, the transmitter 150 and / or sensors 165, 166 may operate at 2.7 micrometers. Figure 2 As shown, the transmittance region 161 can be positioned such that the radiation flow (typically indicated by the arrow) can flow from the emitter 150 through the transmittance region 161 and to the sensors 165, 166 without being obstructed by the windows 106, 108 (e.g., the opaque region 160). Similarly, the opaque region 160 can be positioned within the area of ​​the windows 106, 108, which are outside the radiation flow, to shield the workpiece 110 and, in particular, the sensors 165, 166 from radiation from the heat sources 130, 140 in the measurement wavelength range. For example, in some embodiments, the transmittance region 161 may be included for sensors and / or emitters operating at a wavelength of 2.7 micrometers.

[0063] In some embodiments, transmitter 150 and / or sensors 165, 166 can be phase-locked. For example, in some embodiments, transmitter 150 and / or sensors 165, 166 can be operated according to a phase-locking mechanism. For example, although the opaque region 160 can be configured to block most of the stray radiation from heat sources 130, 140 at the first wavelength, in some cases, as discussed above, sensors 165, 166 can still detect stray radiation. Despite the presence of stray radiation, operating transmitter 150 and / or sensors 165, 166 according to a phase-locking mechanism can help improve the accuracy of intensity measurements.

[0064] For example, in some embodiments, the radiation emitted by emitter 150 can be pulsed at a pulse frequency. The pulse frequency can be selected to be or include frequencies having little or no radiation component in the heat treatment system 200. For example, in some embodiments, the pulse frequency can be approximately 130 Hz. In some embodiments, a 130 Hz pulse frequency can be particularly advantageous because heat sources 130, 140 may substantially not emit radiation at a frequency of 130 Hz. Additionally and / or optionally, pulse frequency phase-locked sensors 165, 166 can be used. For example, the heat treatment system 200 (e.g., a controller, such as...) Figure 1 The controller 175 can isolate measurements (e.g., intensity measurements) from sensors 165, 166 based on pulse frequency. In this way, the heat treatment system 200 can reduce interference from stray radiation in the measurements of sensors 165, 166.

[0065] An example phase-locking mechanism is discussed with reference to Figures 250, 255, and 260. Figure 250 depicts the radiation emitted by emitter 150 over time (e.g., during the duration of heat treatment performed on workpiece 110) within the measurement wavelength range. I IR The radiation intensity emitted by transmitter 150 can be emitted as pulse 251, as shown in Figure 250. For example, transmitter 150 can generate pulses using a chopper (not shown). The chopper may include one or more blocking sections and / or one or more passing sections. The chopper can rotate within the field of view of transmitter 150, such that the continuous radiation stream from transmitter 150 is intermittently interrupted by the blocking sections and passed through by the passing sections at a pulse frequency. Therefore, rotation of the chopper can convert the continuous radiation stream emitted by transmitter 150 into a pulsed radiation stream at a pulse frequency.

[0066] Figure 255 depicts the intensity of transmitted radiation measured by transmission sensor 165 over time. I T Similarly, Figure 260 depicts the intensity of reflected radiation measured over time by the reflection sensor 166.I R Curves 255 and 260 show that stray radiation in the chamber (shown by stray radiation plots 256 and 261, respectively) can increase over time (e.g., as the temperature of workpiece 110 increases). This can be attributed to, for example, the decrease in transmittance of workpiece 110 and / or the increase in radiation of workpiece 110, taking into account, the increase in the temperature of workpiece 110, the increase in the intensity of heat sources 130 and 140, and / or various other factors related to the heat treatment of workpiece 110.

[0067] During the time points when transmitter 150 does not emit radiation, sensors 165 and 166 can acquire measurements corresponding to stray radiation curves 256 and 261, respectively (e.g., stray radiation measurements). Similarly, during the time points when transmitter 150 emits radiation (e.g., pulse 251), sensors 165 and 166 can acquire measurements corresponding to total radiation curves 257 and 262, respectively (e.g., total radiation measurements). Therefore, the transmitted radiation intensity can be determined at least in part based on the difference between the time-coordinated (e.g., subsequent) total radiation measurement (e.g., representative curve 257) and the stray radiation measurement (e.g., representative curve 256). I T (For example, attributed to transmission τ). Furthermore, it can be determined by the intensity of transmitted radiation. I T With reference strength I 0 The ratio of the two values ​​determines the transmission τ. Similarly, the reflected radiation intensity can be determined at least in part based on the difference between time-coordinated (e.g., subsequent) total radiation measurements (e.g., representative curve 262) and stray radiation measurements (e.g., representative curve 261). I R (For example, attributed to reflection ρ). Furthermore, the intensity of reflected radiation can be... I R With reference strength I 0 The ratio of the two values ​​determines the reflection ρ. In some embodiments, when the workpiece 110 is not present in the heat treatment system 200, the reference intensity can be measured by sensors 165 and 166. I 0 As a result of pulsed and / or continuous radiation from transmitter 150, the emissivity ε can be calculated using the following formula, based on transmission τ and reflection ρ:

[0068]

[0069] Figure 3An example heat treatment system 300 according to an example aspect of this disclosure is depicted. The heat treatment system 300 can be configured to perform heat treatment on a workpiece 110 and / or measure the temperature of the workpiece 110. In particular, the heat treatment system may include reference... Figure 1 The heat treatment system 100 discusses one or more components. Specifically, Figure 3 At least the components for determining the temperature of workpiece 110 based on transmission and / or emission are depicted, including at least a central emitter 152 and a central sensor 167. In some embodiments, an edge emitter 154 and / or an edge sensor 168 may operate similarly to the central emitter 152 or the central sensor 154, and operate on the edge portions of workpiece 110, as shown in the reference. Figure 3 The subject of discussion, but for illustrative purposes only Figure 3 The middle part is omitted. This will be referenced below. Figure 4 Further discussion.

[0070] like Figure 3 As shown, the central emitter 152 can be configured to emit infrared radiation directed at a right angle to the surface of the workpiece 110, such as... Figure 3 As indicated by the arrows in the diagram. The transmitted portion of the radiation emitted by the central emitter 152 passes through the workpiece 110 and is incident on the central sensor 167. In some embodiments, the transmission region 161 of the windows 106, 108 may be located within the field of view of the central emitter 152 and / or the sensor 167. For example, the central emitter 152 and / or the central sensor 167 may operate within a measurement wavelength range, and the transmission region 161 is transparent to that measurement wavelength range. For example, in some embodiments, the central emitter 152 and / or the central sensor 167 may operate at 2.7 micrometers. Figure 3 As shown, the transmittance region 161 can be positioned such that the radiation flow (typically indicated by the arrow) can flow from the central emitter 152 through the transmittance region 161 and to the central sensor 167 without being obstructed by windows 106, 108 (e.g., the opaque region 160). Similarly, the opaque region 160 can be provided in the region on windows 106, 108, outside the radiation flow, to shield the workpiece 110, and especially the central sensor 167, from radiation from heat sources 130, 140 in the measurement wavelength range. For example, in some embodiments, the transmittance region 161 may be included for sensors and / or emitters operating at a wavelength of 2.7 micrometers.

[0071] However, in some embodiments, the transmission region 161 in the window 106, positioned within the field of view of the central emitter 152, may undesirably allow radiation emitted by the heat source 130 to contaminate measurements of the central sensor 167 and / or other sensors (not shown) in the heat treatment system 300. For example, in some embodiments, the central sensor 167 may also be configured to measure thermal radiation emitted by the workpiece 110 within a measurement wavelength range, for which the transmission region 161 is transparent. If the transmission region 161 is positioned within the field of view of the central emitter 152, the radiation emitted by the heat source 130 may pose a greater risk of contaminating the workpiece's emission measurements.

[0072] One solution to this problem is to omit the transparent region 161 in the field of view of the central emitter 152 and instead include the opaque region 160. Furthermore, the central emitter 152 and / or the central sensor 167 can operate at a second wavelength within the measurement wavelength range, where the opaque region 160 is at least partially transparent to that measurement wavelength range. For example, in some embodiments, the second wavelength could be 2.3 micrometers. In this way, despite the presence of the opaque region 160, radiation emitted by the central emitter 152 can pass through windows 106 and 108 and be measured by the central sensor 167 without needing to include the potentially contaminating transparent region. Moreover, because the opaque region 160 is included, measurements from the central sensor 167 representing the intensity of emitted radiation from the workpiece 110 (e.g., emitted radiation measurement) (e.g., at the temperature of the emitted radiation from the workpiece 110, e.g., above about 600 °C) are not contaminated by stray radiation. However, the solutions discussed above may introduce additional problems. Since radiation at the second wavelength from the central emitter 152 can pass through the opaque region 160, stray radiation at the second wavelength from heat sources 130 and 140 can also pass through the opaque region 160.

[0073] Therefore, in some embodiments, the central transmitter 152 and / or the central sensor 167 can be phase-locked. In some embodiments, the central transmitter 152 and / or the central sensor 167 can be operated according to a phase-locking mechanism. For example, although the opaque region 160 can be configured to block most of the stray radiation from the heat sources 130, 140 at the first wavelength, in some cases, stray radiation, especially at the second wavelength, can still be detected by the central sensor 167, as described above. Despite the presence of stray radiation, operating the central transmitter 152 and / or the central sensor 167 according to the phase-locking mechanism can help improve the accuracy of intensity measurements.

[0074] For example, in some embodiments, the radiation emitted by the central emitter 152 can be pulsed at a pulse frequency. The pulse frequency can be selected to be, or include, a frequency with little or no radiation component in the heat treatment system 300. For example, in some embodiments, the pulse frequency can be approximately 130 Hz. In some embodiments, a 130 Hz pulse frequency can be particularly advantageous because heat sources 130, 140 may substantially not emit radiation at a frequency of 130 Hz. Additionally and / or optionally, the central sensor 167 can be phase-locked based on the pulse frequency. For example, the heat treatment system 300 (e.g., a controller, such as...) Figure 1 The controller 175 can isolate measurements (e.g., intensity measurements) from the central sensor 167 based on pulse frequency. In this way, the heat treatment system 300 can reduce interference from stray radiation in the measurements taken by the central sensor 167.

[0075] An example phase-locking mechanism is discussed with reference to Figures 310 and 320. Figure 310 depicts the radiation emitted by the central emitter 152 over time (e.g., the duration of heat treatment performed on workpiece 110) within the measurement wavelength range. I IR The radiation intensity. Figure 320 depicts the transmitted radiation intensity measured by the central sensor 167 over time. I T As shown in Figure 310, the radiation intensity emitted by the central emitter 152 can be emitted as a pulse 311. For example, the central emitter 152 can generate pulses via a chopper 302. The chopper 302 may include one or more blocking portions 305 and / or one or more passing portions 306. The chopper 302 can rotate within the field of view of the central emitter 152 such that the continuous radiation stream from the central emitter 152 is intermittently interrupted by the blocking portions 305 and passed through by the passing portions 306 at a pulse frequency. Therefore, rotation of the chopper 302 can convert the continuous radiation stream emitted by the central emitter 152 into a pulsed radiation stream at a pulse frequency.

[0076] During the time points when the central transmitter 152 does not emit radiation, the central sensor 167 can acquire measurements corresponding to stray radiation curve 312 (e.g., stray radiation measurement). Similarly, during the time points when the central transmitter 152 emits radiation (e.g., pulse 311), the central sensor 167 can acquire measurements corresponding to total radiation curve 313 (e.g., total radiation measurement). Therefore, the transmitted radiation intensity can be determined at least in part based on the difference between the time-coordinated (e.g., subsequent) total radiation measurement (e.g., representative curve 313) and the stray radiation measurement (e.g., representative curve 312). I T (For example, attributed to transmission τ). Furthermore, it can be determined by the intensity of transmitted radiation.I T With reference strength I 0 The ratio determines the transmission τ. For example, when the workpiece 110 is not present in the heat treatment system 300, the reference intensity can be measured by the center sensor 167. I 0 As a result of pulsed and / or continuous radiation from the central transmitter 152, the transmission τ can be compared with the transmission curve (e.g., Figure 6A The transmission curves 602, 604, and 606, respectively, correspond to specific workpiece components, and / or Figure 6B The normalized workpiece transmittance curve (652) is compared to determine the workpiece temperature.

[0077] Figure 320 illustrates that stray radiation in the chamber (as shown in stray radiation curve 312) can increase over time (e.g., as the temperature of workpiece 110 increases). This can be attributed to, for example, the decrease in transmittance of workpiece 110 and / or the increase in radiation of workpiece 110, taking into account, the increase in the intensity of heat sources 130, 140, and / or various other factors related to the heat treatment of workpiece 110. For example, as can be seen in Figure 320, stray radiation curve 312 and total radiation curve 313 tend to converge over time (e.g., as the temperature increases). This can be a result, for example, of the decrease in transmittance of workpiece 110 relative to the increase in temperature. Therefore, in some cases (e.g., for silicon workpieces), the transmission-based temperature measurement described above may exhibit reduced reliability above a certain temperature (e.g., about 600 °C). Therefore, according to an exemplary aspect of this disclosure, a heat treatment system (e.g., any one of heat treatment systems 100, 200, 300) can transition from a first temperature measurement process (e.g., a transmission-based temperature measurement process) to a second temperature measurement process (e.g., an emission-based temperature measurement process) at a temperature threshold. For example, the temperature threshold can be approximately 600 °C. The temperature threshold can correspond to a workpiece temperature at which workpiece 110 exhibits a significant amount of blackbody radiation at a wavelength that can be detected by the central sensor 167. Additionally and / or alternatively, the temperature threshold can correspond to a workpiece temperature at which radiation emitted by workpiece 110 to the central emitter 152 is impermeable. For example, in some embodiments, the temperature threshold can correspond to a point where stray radiation curve 312 and total radiation curve 313 have converged, or in other words, the transmitted radiation intensity. I T The amplitude is lower than the amplitude threshold.

[0078] For example, in some embodiments, the central sensor 167 may be configured to measure radiation emitted by the workpiece 110 within a measurement wavelength range. For example, in some embodiments, the central sensor 167 may be a dual-head pyrometer having a first head configured to measure a first wavelength within the measurement wavelength range. In embodiments where the opaque region 160 comprises hydroxyl-doped quartz, the first wavelength may be or include a wavelength that is transparent to the transparent region 161 and / or opaque to the opaque region 160, such as 2.7 micrometers. The first wavelength may additionally correspond to the wavelength of blackbody radiation emitted by the workpiece 110. Additionally, the central sensor 167 may have a second head configured to measure a second wavelength within the measurement wavelength range. In embodiments where the opaque region 160 comprises hydroxyl-doped quartz, the second wavelength may be or include a wavelength that is opaque to the opaque region 160, such as 2.3 micrometers. The second wavelength may additionally correspond to the wavelength emitted by the central emitter 152.

[0079] Therefore, according to an exemplary aspect of this disclosure, for temperatures below a temperature threshold of the workpiece 110, the central sensor 167 can obtain a transmission measurement associated with the transmission of the workpiece 110, and for temperatures above the temperature threshold, it can also obtain an emission measurement associated with the intensity of the blackbody radiation emitted by the workpiece 110. Thus, as described above, at temperatures below the temperature threshold, the temperature of the workpiece 110 can be determined by transmission measurement. Additionally and / or optionally, at temperatures above the temperature threshold, the temperature of the workpiece 110 can be determined by emission measurement. For example, the temperature of the workpiece can be determined by emission measurement based on the following equation:

[0080]

[0081] Figure 4 An example temperature measurement system 400 according to an example aspect of this disclosure is described. The temperature measurement system 400 can be configured to measure the temperature of a workpiece 110, which may be at least partially supported by a support ring 109. The temperature measurement system 400 may include a center emitter 152 and an edge emitter 154. Furthermore, the temperature measurement system 400 may include a center sensor 167 and an edge sensor 168. The emitters 152, 154 and / or sensors 167, 168 may be configured as described above. Figure 3The center emitter 152 and / or center sensor 168 operate as discussed. For example, the center emitter 152 and center sensor 167 can be configured such that radiation emitted by the center emitter 152 passes through the central portion 111 of the workpiece 110 and then incident on the center sensor 167. Similarly, an edge emitter 154 and edge sensor 168 can be configured such that radiation emitted by the edge emitter 154 passes through the edge portion 112 of the workpiece 110 and incident on the edge sensor 168. Thus, the center sensor 167 can be configured to obtain a temperature measurement of the central portion 111, and / or the edge sensor 168 can be configured to obtain a temperature measurement of the edge portion 112. In some embodiments, the central portion 111 may include a portion of the workpiece defined as less than about 50% of the radius r of the workpiece, for example, about 10% of the radius r. In some embodiments, the edge portion may include a portion of the workpiece defined as greater than about 50% of the radius r of the workpiece, for example, about 90% of the radius r.

[0082] Figure 5A A plot 500 depicts an example transmission curve 502 of an example material that constitutes an example opaque region. For example, a transmission curve 502 of an example material, such as hydroxyl-doped quartz, is shown. Figure 5A As shown, the example opaque region may be substantially opaque to some wavelengths and substantially transparent to others. Specifically, the example transmission curve 502 includes an opaque range 504 and a partially opaque range 506. As discussed herein, the measurement wavelength range may advantageously include wavelengths within the opaque range 504 and / or the partially opaque range 506. For example, radiation within the opaque range 504 and / or the partially opaque range 506 may be at least partially blocked by the exemplary opaque region, which prevents radiation emitted by the heating lamp from entering the heat treatment chamber and contaminating measurements by sensors configured to measure the opaque range 504 and / or the partially opaque range 506.

[0083] Figure 5B A drawing 520 depicts the transmission curve 522 of an example material constituting the example transmission region. For example, a transmission curve 522 of an example material, such as hydroxyl-free quartz, is shown. Figure 5B As shown, the example transmittance region may be substantially transmittant at certain wavelengths. Although example transmittance curve 522 is depicted as substantially transmittant at most wavelengths, the example transmittance region may additionally include non-transmittant ranges. Typically, it is desirable for the example transmittance region to be within the measurement range (e.g., in relation to...). Figure 5A The wavelengths corresponding to the non-transparent range 504 and / or the partially non-transparent range 506 are transparent.

[0084] Figure 6APlot 600 depicts example transmission curves 602, 604, and 606 for three example workpiece types. For example, curve 602 is associated with workpieces with low reflectivity, curve 604 with workpieces with medium reflectivity (e.g., bare workpieces), and curve 606 with workpieces with high reflectivity. Figure 6A As shown, although each of curves 602, 604, and 606 follows a general trend, the transmittance value for each workpiece may differ based on its surface characteristics (e.g., reflectivity). Therefore, Figure 6B A plot 650 depicts an example normalized or nominal workpiece transmission curve 652. (See plot 650.) Figure 6B As shown, the normalized workpiece transmission curve 652 represents the transmission of a specific workpiece from a maximum of 1 to a minimum of 0, but is independent of the specific transmission value of the workpiece. In other words, the normalized workpiece transmission curve 652 can be similar to and / or identical to each of a low-reflectivity workpiece, a bare workpiece, and / or a high-reflectivity workpiece. Therefore, normalized transmission measurements obtained for a workpiece can be compared with the normalized workpiece transmission curve 652, such that transmission can be directly related to temperature and independent of the surface characteristics of the workpiece.

[0085] Figure 7 It shows a method for use in heat treatment systems (such as, for example, Figure 1-3 A flowchart of an example method 700 for measuring the temperature of a workpiece in a heat treatment system (100, 200, or 300). For illustrative and discussion purposes, Figure 7 The steps are described in a specific order. Those skilled in the art who use the disclosure provided herein will understand that various steps of any method described herein may be omitted, extended, performed concurrently, rearranged, and / or modified in various ways without departing from the scope of this disclosure. Furthermore, various additional steps (not shown) may be performed without departing from the scope of this disclosure.

[0086] Method 700 may include, at 702, one or more infrared emitters emitting infrared radiation directed toward one or more surfaces of a workpiece. For example, in some embodiments, the one or more infrared emitters may emit radiation having a first wavelength, and the one or more infrared emitters may emit radiation having a second wavelength.

[0087] Method 700 may include, at 704, one or more windows blocking at least a portion of broadband radiation emitted by one or more heating lamps from incident on one or more infrared sensors, the one or more heating lamps being configured to heat a workpiece. For example, in some embodiments, the one or more windows may block at least a portion of the broadband radiation within at least a portion of the measurement range.

[0088] Method 700 may include: at 706, one or more infrared sensors measuring a transmitted portion of infrared radiation emitted by at least one of one or more infrared emitters and passing through one or more surfaces of a workpiece. For example, a first portion of the transmitted portion may be incident on a first transmission sensor to obtain a first transmittance measurement. The first transmitted portion may correspond to an emitter and / or sensor of an emissivity measurement system. In some embodiments, the first transmitted portion may have an associated first wavelength. Additionally and / or optionally, a second portion of the transmitted portion may be incident on at least one second transmission sensor to obtain at least one second transmission measurement. In some embodiments, at least one second transmission sensor may also be configured to measure radiation emitted by the workpiece. In some embodiments, the second transmitted portion may have an associated second wavelength. In some embodiments, the first wavelength may be blocked by one or more windows, and / or the second wavelength may at least partially pass through the one or more windows. For example, in some embodiments, the first transmitted portion is associated with a first wavelength in a measurement wavelength range, and the second transmitted portion is associated with a second wavelength in a measurement wavelength range. Wherein, one or more windows block radiation at the first wavelength and allow radiation at the second wavelength.

[0089] Method 700 may include, at 708, one or more infrared sensors measuring a reflected portion of infrared radiation emitted by at least one of one or more infrared emitters and reflected by one or more surfaces of a workpiece. For example, the reflected portion may be incident on a reflection sensor to obtain a reflection measurement. In some embodiments, the reflection sensor may be part of an emissivity measurement system.

[0090] In some embodiments, measuring a portion (e.g., a transmissive portion and / or a reflective portion) of infrared radiation emitted by at least one of one or more infrared emitters using one or more infrared sensors may include phase locking of one or more infrared sensors and / or one or more infrared emitters. For example, phase locking of one or more infrared sensors and / or one or more infrared emitters may include causing at least one of the one or more infrared emitters to pulse at a pulse frequency. As an example of causing one or more emitters to pulse, a chopper wheel with one or more slits may rotate within the field of view of one or more emitters, such that a continuous stream of radiation from one or more emitters is intermittently allowed to pass through the chopper wheel at a pulse frequency. Thus, a continuous stream of radiation can be converted into a pulsed stream of radiation at a pulse frequency by rotation of the chopper wheel.

[0091] Additionally and / or optionally, phase-locking one or more infrared sensors and / or one or more infrared emitters may include isolating at least one measurement from one or more infrared sensors, at least in part, based on the pulse frequency. As an example, a measurement from one or more infrared sensors (e.g., a measurement indicating the intensity of radiation incident on one or more infrared sensors), i.e., a measurement at and / or in phase with the pulse frequency, can be compared with a measurement not at and / or out of phase with the measurement at the pulse frequency, such as by subtracting a subsequent measurement at twice the pulse frequency. Thus, the signal contribution from the component at the pulse frequency (e.g., the emitter) can be isolated from interfering components (e.g., stray radiation, such as from a heating lamp). In other words, a sensor measurement not phase-locked to the pulse frequency (e.g., obtained at the same or higher frequency as the pulse frequency and / or obtained out of phase with the phase-locked measurement) may indicate only stray radiation in the chamber, and / or a sensor measurement phase-locked to the pulse frequency may indicate the sum of stray radiation and emitted radiation from the emitter. Therefore, measurements indicating emitted radiation from the transmitter can be separated by subtracting the amount of stray radiation indicated by measurements not phase-locked. As an example, if the pulse frequency is 130 Hz, the sensor can obtain measurements at 260 Hz or higher, such that one or more stray intensity measurements correspond to each phase-locked measurement. In this way, the thermal processing system can reduce interference from stray radiation (e.g., stray light) in the sensor's measurements.

[0092] Method 700 may include: at 710, determining the temperature of the workpiece based at least in part on the transmissive and reflective portions. In 710, the temperature of the workpiece may be below about 600 °C. For example, in some embodiments, determining the temperature of the workpiece may include: determining the emissivity of the workpiece based at least in part on the transmissive and reflective portions, and determining the temperature of the workpiece based at least in part on the transmissive portions and the emissivity of the workpiece. For example, in some embodiments, the emissivity of the workpiece may be determined based at least in part on a first transmission measurement and a reflection measurement.

[0093] Method 700 may include, at 712, one or more infrared sensors measuring an emitted radiation measurement indicating infrared radiation emitted by the workpiece. For example, the emitted radiation measurement may indicate the intensity of infrared radiation emitted by the workpiece and incident on one or more sensors. According to an example aspect of this disclosure, an emitted radiation measurement can be obtained once the temperature of the workpiece is sufficiently high that the workpiece is no longer transmissible to infrared radiation from the emitter and / or begins to emit significant blackbody radiation at wavelengths (e.g., within at least a portion of the measurement wavelength range) configured to be measured by one or more infrared sensors.

[0094] In some embodiments, the emitted radiation measurement may correspond to the wavelength of infrared radiation blocked by one or more windows. For example, the emitted radiation measurement may correspond to a wavelength that is and / or is included within a portion of the measurement wavelength range. For example, in some embodiments, the emitted radiation measurement may correspond to the intensity of infrared radiation having a wavelength of 2.7 micrometers.

[0095] Method 700 may include, at 714, determining the temperature of a workpiece based at least in part on an emitted radiation measurement. In 714, the temperature of the workpiece may be higher than about 600 °C. For example, determining that the temperature of the workpiece is higher than about 600 °C may include comparing the emitted radiation measurement with a blackbody radiation profile associated with the workpiece. The blackbody radiation profile can correlate the intensity of the emitted blackbody radiation with temperature, allowing the temperature to be determined based on the measured intensity (e.g., the emitted radiation measurement).

[0096] The system implementation method 700 can span a wider temperature range over which the temperature of the workpiece can be measured. For example, method 700 may include: determining the workpiece temperature, at least in part, based on the transmitting and reflecting portions, according to steps 702-710, for temperatures where emitted radiation measurements are not practically available (e.g., below about 600 °C). Alternatively, method 700 may include: determining the workpiece temperature, at least in part, based on emitted radiation measurements, according to steps 712-714, for temperatures where emitted radiation measurements are practically available (e.g., above about 600 °C).

[0097] Figure 8 A flowchart depicts an example method 800 for calibrating sensor reference strength in a heat treatment system, such as, for example Figure 1-3 The heat treatment system in the middle is 100, 200, or 300. For illustrative and discussion purposes, Figure 8 The steps are described in a specific order. Those skilled in the art who use the disclosure provided herein will understand that various steps of any method described herein may be omitted, extended, performed concurrently, rearranged, and / or modified in various ways without departing from the scope of this disclosure. Furthermore, various additional steps (not shown) may be performed without departing from the scope of this disclosure.

[0098] Method 800 may include: at 802, emitting a first amount of infrared radiation from a respective transmitter among a plurality of infrared emitters. Method 800 may include: at 804, determining a second amount of infrared radiation incident on a respective sensor among a plurality of infrared sensors. Method 800 may include: at 806, determining a reference intensity associated with the respective transmitter and the respective sensor, at least in part based on the variation between the first and second amounts.

[0099] According to an example aspect of this disclosure, a reference intensity, denoted herein, can be determined for each of one or more sensors in a heat treatment system. I 0 When the workpiece is not present in the processing chamber, the reference intensity can correspond to the radiation emitted by the emitter and / or incident on the sensor. In other words, the reference intensity can only be reduced from the intensity of the radiation emitted by the emitter by the contribution of components other than the workpiece in the heat treatment system. This can also correspond to the case where the workpiece is 100% transmitted. In some embodiments, the reference intensity can be measured before the workpiece is inserted into the processing chamber, such as between heat treatments of two workpieces.

[0100] Although the subject matter has been described in detail with reference to specific exemplary embodiments thereof, it should be understood that those skilled in the art, upon gaining an understanding of the foregoing, can readily produce changes, variations, and equivalents to these embodiments. Therefore, the scope of this disclosure is exemplary and not restrictive, and the description does not exclude such modifications, variations, and / or additions to the subject matter that would be obvious to those skilled in the art.

Claims

1. A heat treatment system for performing heat treatment on a semiconductor workpiece, the heat treatment system comprising: A workpiece support plate is configured to support the workpiece. One or more heat sources are configured to heat the workpiece; One or more windows are disposed between the workpiece support plate and the one or more heat sources, the one or more windows including one or more transparent regions that are transparent to at least a portion of electromagnetic radiation within the measurement wavelength range, and one or more opaque regions that are opaque to electromagnetic radiation within the portion of the measurement wavelength range. as well as A temperature measurement system, configured to obtain a temperature measurement indicating the temperature of the workpiece, the temperature measurement system comprising: Multiple infrared emitters are configured to emit infrared radiation; A plurality of infrared sensors, each corresponding to one of the plurality of infrared emitters, each of the plurality of infrared sensors being configured to measure infrared radiation within the measurement wavelength range, and configured such that at least one of the one or more transmission regions is at least partially within the field of view of at least one of the plurality of infrared sensors; and The controller is configured to perform operations, the operations including: At least one first transmission measurement, at least one second transmission measurement, and at least one reflection measurement associated with the workpiece are obtained from the plurality of infrared sensors; When the temperature of the workpiece is below 600 °C, the temperature of the workpiece is determined at least in part based on the at least one first transmission measurement, the at least one second transmission measurement, and the at least one reflection measurement.

2. The heat treatment system according to claim 1, wherein the operation further comprises: One or more emission measurements are obtained from the plurality of infrared sensors, the plurality of emission measurements indicating the intensity of emitted radiation emitted by the workpiece; as well as When the temperature of the workpiece is above 600 °C, the temperature of the workpiece is determined at least in part based on the one or more emission measurements.

3. The thermal processing system of claim 2, wherein, The one or more infrared emitters include a center emitter operable to emit radiation toward a central portion of the workpiece and an edge emitter operable to emit radiation toward an edge portion of the workpiece, wherein the one or more infrared sensors include a center sensor corresponding to the center emitter and an edge sensor corresponding to the edge emitter.

4. The thermal processing system of claim 1, wherein, The one or more heat sources are configured to emit broadband radiation to heat the workpiece.

5. The thermal processing system of claim 4, wherein, The one or more opaque regions are configured to block at least a portion of the broadband radiation emitted by the heat source and within the measurement wavelength range.

6. The thermal processing system of claim 5, wherein, The one or more opaque regions comprise hydroxyl-doped quartz, and wherein the one or more permeable regions comprise hydroxyl-free quartz.

7. The thermal processing system of claim 1, wherein, At least one of the plurality of infrared emitters generates a pulse at a pulse frequency.

8. The thermal processing system of claim 7, wherein, At least one of the at least one first transmission measurement, the at least one second transmission measurement, or the at least one reflection measurement is isolated from the plurality of infrared sensors at least in part based on the pulse frequency.

9. The heat treatment system according to claim 7, wherein, The pulse frequency is 130 Hz.

10. The heat treatment system according to claim 1, wherein, The measurement wavelength range includes at least one of 2.3 micrometers or 2.7 micrometers.

11. The heat treatment system of claim 1, comprising at least one optical notch filter, at least partially disposed within the field of view of at least one of the plurality of infrared sensors, wherein, The optical notch filter is configured to select at least a portion of the measurement wavelength range from the range of wavelengths that can be measured by at least one of the plurality of infrared sensors.

12. The heat treatment system according to claim 1, wherein, The plurality of infrared sensors include one or more pyrometers.

13. The heat treatment system according to claim 1, wherein, When the temperature of the workpiece is below 600 °C, the temperature of the workpiece is determined at least in part based on the at least one first transmission measurement, the at least one second transmission measurement, and the at least one reflection measurement, including: The emissivity of the workpiece is determined at least in part based on the at least one first transmission measurement and the at least one reflection measurement; and The temperature of the workpiece is determined at least in part based on the at least one second transmission measurement and the emissivity of the workpiece.

14. The heat treatment system according to claim 1, wherein, The at least one first transmission measurement and the at least one reflection measurement are associated with a first wavelength of the measurement wavelength range, and the at least one second transmission measurement is associated with a second wavelength of the measurement wavelength range, wherein the one or more opaque regions are opaque to the first wavelength and transparent to the second wavelength.

15. The heat treatment system according to claim 1, wherein, The controller is configured to determine the reference intensity of at least one of the plurality of infrared sensors by means of the following operations when there is no workpiece in the heat treatment system: A first amount of infrared radiation is emitted from the respective transmitters of the plurality of infrared transmitters; Determine a second amount of infrared radiation incident on a corresponding sensor among the plurality of infrared sensors; as well as The reference intensity associated with the respective transmitter and the respective sensor is determined at least in part based on the change between the first quantity and the second quantity.

16. A method for measuring the temperature of a workpiece in a heat treatment system, the method comprising: One or more infrared emitters emit infrared radiation within the measurement wavelength range that is directed toward one or more surfaces of the workpiece; One or more windows block at least a portion of broadband radiation emitted by one or more heating lamps from incident onto one or more infrared sensors, the one or more heating lamps being configured to heat the workpiece; wherein the one or more windows include one or more transparent regions that are transparent to at least a portion of electromagnetic radiation within the measurement wavelength range, and one or more opaque regions that are opaque to electromagnetic radiation within the portion of the measurement wavelength range. The one or more infrared sensors measure the transmitted portion of the infrared radiation, which is emitted by at least one of the one or more infrared emitters and passes through the one or more surfaces of the workpiece; wherein at least one of the one or more transmitted regions is at least partially within the field of view of at least one of the one or more infrared sensors; The one or more infrared sensors measure the reflected portion of the infrared radiation, the reflected portion of which is emitted by at least one of the one or more infrared emitters and reflected by the one or more surfaces of the workpiece; and A first temperature measurement indicating the temperature of the workpiece is determined, at least in part based on the transmissive portion and the reflective portion, wherein the temperature of the workpiece is below 600 °C.

17. The method of claim 16, further comprising: The one or more infrared sensors measure emitted radiation, the emitted radiation measurement indicating the infrared radiation emitted by the workpiece; as well as A second temperature measurement indicating the temperature of the workpiece is determined, at least in part based on the emitted radiation measurement, wherein the temperature of the workpiece is above 600 °C.

18. The method according to claim 17, wherein, Determining a second temperature measurement indicating the temperature of the workpiece, at least in part based on the emitted radiation measurement, wherein the temperature of the workpiece is above 600 °C, includes comparing the emitted radiation measurement with a blackbody radiation curve associated with the workpiece.

19. The method of claim 16, wherein determining the temperature of the workpiece is based at least in part on the transmissive portion and the reflective portion, wherein the temperature of the workpiece is below 600 °C, comprising: The emissivity of the workpiece is determined at least in part based on the transmissive portion and the reflective portion; as well as The temperature of the workpiece is determined at least in part based on the emissivity of the transmissive portion and the workpiece.

20. The method of claim 16, wherein, The method further includes: At least one of the one or more infrared emitters generates a pulse at a pulse frequency; and At least one measurement is isolated from the one or more infrared sensors, at least in part based on the pulse frequency.

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