Temperature measurement and control method and apparatus for semiconductor thermal processing

Abstract

The application provides a temperature measurement and control method and device for a semiconductor heat treatment process, comprising: synchronously measuring thermal radiation intensity and emissivity of corresponding positions on the back of a wafer by multiple pyrometers; calculating a first fluctuation value of the emissivity measured by the pyrometers; if the fluctuation value is less than or equal to a preset threshold, using the emissivity measured by a single pyrometer for temperature calculation of all the pyrometers; otherwise, calculating a second fluctuation value between the emissivities measured by adjacent pyrometers, and grouping the adjacent pyrometers with the second fluctuation value less than the preset threshold into the same group, and using the emissivity measured by a representative pyrometer in each group to calculate the temperature of all the pyrometers at corresponding positions in the group; and controlling each heating area of a heating lamp group to perform zoned temperature control on the wafer according to the calculated wafer temperature at multiple positions. The application can use multiple control strategies to ensure process consistency and stability, and realize high-precision and high-uniformity temperature control.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, and in particular to a temperature measurement and control method and device for a semiconductor thermal processing process, which is particularly suitable for high-precision and high-uniformity measurement and control of wafer temperature in a rapid thermal processing (RTP) process. BACKGROUND

[0002] In semiconductor manufacturing, rapid thermal processing (RTP) is a key process, which is widely used in annealing, oxidation, thin film deposition and other steps. The RTP process requires the wafer to be rapidly heated to a target temperature (for example, 180℃ to 1200℃) in a very short time, and to maintain a very high temperature uniformity and control accuracy. In advanced processes, the temperature deviation is usually required to be less than 1℃.

[0003] Temperature is the most core parameter in the RTP process. At present, the mainstream non-contact temperature measurement technology adopts an infrared pyrometer. However, the emissivity of the wafer surface is not fixed, which is affected by the surface material, film thickness, surface roughness and temperature itself. In order to accurately calculate the temperature, the thermal radiation intensity and the emissivity of the measured point must be known at the same time.

[0004] Moreover, in wafer production, especially in wafer foundry production, according to different products, the wafer surface is usually deposited with different materials (such as polysilicon, silicon dioxide, silicon nitride, metal, etc.) and different film thicknesses and surface distributions, which result in differences in emissivity of the rotating heated wafer surface at different positions and dynamic changes of the emissivity relative to the fixed pyrometer in the reaction chamber. In the prior art, the measurement of the wafer emissivity when the wafer is measured by the non-contact method usually has only 1-2 positions. By applying the measured wafer emissivity to all pyrometers with only radiation intensity measurement function, the wafer temperature at the position is finally calculated. If the difference between the position for measuring the wafer emissivity and the detection position of the pyrometer with only radiation intensity measurement function on the wafer is large, the temperature measurement will be inaccurate due to the large deviation of the actual emissivity of the detection position of the pyrometer from the measured emissivity, which affects the process consistency of different products in the same process. SUMMARY

[0005] The present application aims to provide a temperature measurement and control method and device for a semiconductor thermal processing process, which can use multiple control strategies to ensure process consistency and stability, and can realize high-precision and high-uniformity temperature control.

[0006] To solve the above technical problems, the embodiment of the present application provides a temperature measurement and control method for a semiconductor heat treatment process, which is applied to a heat treatment device, the heat treatment device comprises a heating lamp group divided into multiple heating areas and multiple pyrometers corresponding to multiple measurement sites on the back surface of a wafer, and the method comprises the following steps:

[0007] synchronously measuring the thermal radiation intensity and the emissivity of the corresponding positions on the back surface of the wafer by the multiple pyrometers; calculating a first fluctuation value of the emissivity measured by the multiple pyrometers; if the first fluctuation value is less than or equal to a preset threshold value, designating the emissivity measured by a single pyrometer as a common emissivity for temperature calculation of all the pyrometers; if the first fluctuation value is greater than the preset threshold value, calculating a second fluctuation value between the emissivities measured by adjacent pyrometers, and grouping the adjacent pyrometers with the second fluctuation value less than the preset threshold value into the same group, and designating a representative pyrometer in each group, and using the emissivity measured by the representative pyrometer to calculate the temperature of the corresponding positions of all the pyrometers in the group; and controlling each heating area of the heating lamp group to perform zoned temperature control on the wafer according to the calculated wafer temperatures of the multiple positions.

[0008] Optionally, before the step of synchronously measuring the thermal radiation intensity and the emissivity of the corresponding positions on the back surface of the wafer by the multiple pyrometers, the method further comprises the following steps: reading the recipe information of the current wafer; determining whether a process matching requirement is designated in the recipe information; if the process matching requirement is designated, setting the number of heating lamp groups participating in wafer heating, the number and distribution of pyrometers participating in emissivity measurement, and the number and distribution of pyrometers participating in temperature control according to a preset matching mode.

[0009] Optionally, when grouping, if the pyrometers located at the edge of the wafer are separately grouped into a group, the emissivity measured by the single pyrometer is subjected to signal processing to filter out the periodic noise related to wafer rotation, and then the processed emissivity is used for temperature calculation of the corresponding position of the pyrometer.

[0010] Optionally, the single pyrometer designated as the source of the common emissivity is a pyrometer located at the middle position of the multiple pyrometers; and / or, the representative pyrometer is a pyrometer closer to the center of the wafer in each group.

[0011] The embodiment of the present application further provides a semiconductor heat treatment device, which comprises: a reaction chamber;

[0012] A support mechanism for supporting and rotating a wafer; a heating lamp set above the wafer for heating the wafer, the heating lamp set being divided into a plurality of independently controllable heating regions; a plurality of pyrometers arranged below the wafer, corresponding to a plurality of measurement sites on the back of the wafer; a control system in communication with the heating lamp set and the plurality of pyrometers, configured to perform the method of any one of claims 1-4.

[0013] Optionally, the pyrometer comprises: an active emissivity measurement module for emitting detection light to the wafer and receiving its reflected light to calculate the emissivity; a temperature measurement module for receiving thermal radiation light of the wafer to calculate the temperature; a logic circuit for receiving signals of the active emissivity measurement module and the temperature measurement module, and calculating the emissivity and temperature according to the signals; wherein the active emissivity measurement module and the temperature measurement module share at least part of the optical path elements.

[0014] Optionally, the active emissivity measurement module comprises: a pulsed light source for emitting pulsed light of a specific wavelength; a first photodetector for monitoring the light output state of the pulsed light source; a beam splitter arranged in the light path of the pulsed light source for reflecting part of the pulsed light to the wafer and transmitting the reflected light returned from the wafer to a second photodetector; a light guide element for guiding light to and from the wafer; a first mirror for reflecting the pulsed light from the beam splitter to the light guide element and reflecting the light received by the light guide element from the thermal radiation of the wafer; a second mirror for reflecting the reflected light from the beam splitter to the second photodetector; a first filter arranged between the pulsed light source and the beam splitter; a second filter arranged between the beam splitter and the second mirror, the first filter and the second filter being used to select light of a specific wavelength band; wherein the logic circuit is configured to calculate the reflectivity of the wafer by comparing the pulsed light intensity information received by the first photodetector and the second photodetector, and then calculate the emissivity.

[0015] Optionally, the logic circuit combines the measured emissivity and thermal radiation intensity to calculate the temperature of the wafer by the blackbody radiation formula.

[0016] Optionally, the temperature measurement module and the active emissivity measurement module share the light guide element, the first mirror, the beam splitter, the second filter, the second mirror and the second photodetector; the thermal radiation light of the wafer passes through the light guide element, the first mirror, the beam splitter, the second filter and the second mirror in turn and is received by the second photodetector.

[0017] Optionally, the emissivity by the formula is calculated as follows, is the transmittance, is the reflectance; the blackbody radiation formula is expressed as:

[0018]

[0019] wherein, is the thermal radiation intensity of an object at a temperature of T at a detection wavelength of λ, is the detection wavelength, is the object temperature, is the Planck constant, is the speed of light, is the Boltzmann constant.

[0020] The embodiments of the present application have the following advantages relative to the prior art:

[0021] 1. By independently and synchronously measuring the emissivity of each pyrometer at the local point, the error of "point instead of surface" is avoided, and true point-to-point accurate temperature measurement is achieved. The temperature measurement error caused by uneven spatial distribution of emissivity is fundamentally solved.

[0022] 2. By calculating the fluctuation value of the emissivity and dynamically selecting the "global uniform" or "grouped calculation" strategy, both the uniform emissivity wafer (such as bare silicon wafer) and the non-uniform emissivity wafer (such as products with different films deposited on the back) can be efficiently processed, and the best balance between accuracy and calculation efficiency is achieved.

[0023] 3. Accurate temperature measurement is the premise of accurate temperature control. The present application provides more realistic wafer temperature field information, so that the multi-zone heating control system can provide more accurate feedback, thereby greatly improving the temperature uniformity within the wafer and the process repeatability between dies, and significantly improving the process consistency and yield.

[0024] 4. The pyrometer design of the present application integrates the emissivity measurement and temperature measurement functions in a single probe and shares most of the optical path components. Not only does it simplify the system structure, reduce cost and maintenance difficulty, but also avoids the error caused by optical path deviation between multiple probes. BRIEF DESCRIPTION OF DRAWINGS

[0025] One or more embodiments are illustrated by way of example in the figures that form a part of this patent document, these example are not intended to limit the embodiments, elements having the same reference numbers in the figures indicate like elements, unless otherwise expressly stated, the figures in the drawings do not constitute a proportional limitation.

[0026] Figure 1 is a flowchart of a temperature measurement and control method for a semiconductor heat treatment process according to an embodiment of the present application;

[0027] Figure 2 This is a schematic diagram of the structure of a semiconductor heat treatment apparatus according to an embodiment of this application;

[0028] Figure 3 This is a schematic diagram of the structure of a wafer according to an embodiment of this application;

[0029] Figure 4 This is a schematic diagram of the structure of a pyrometer according to an embodiment of this application;

[0030] Figure 5 This is a schematic diagram of the structure of a pyrometer according to another embodiment of this application. Detailed Implementation

[0031] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] It should be noted that the following description covers various aspects of embodiments within the scope of the appended claims. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0033] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0034] Additionally, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that practice can be carried out without these specific details.

[0035] This application provides a temperature measurement and control method for semiconductor thermal processing. The method is applied to a thermal processing apparatus, which includes heating lamps divided into multiple heating zones and multiple high-temperature gauges corresponding to multiple measurement points on the back side of the wafer. The method includes the following steps: Figure 1 As shown:

[0036] In step 101, the thermal radiation intensity and emissivity at corresponding locations on the back side of the wafer are simultaneously measured using multiple pyrometers. Specifically, the multiple pyrometers in this embodiment can simultaneously measure thermal radiation intensity and emissivity.

[0037] In step 102, the first fluctuation value of the emissivity measured by multiple pyrometers is calculated. In this embodiment, seven pyrometers are used as an example. This first fluctuation value can be determined by subtracting the absolute value of the minimum value from the maximum value of the emissivity measured by the seven pyrometers, for example, |max-min|.

[0038] It should be noted that the number of pyrometers can be selected as needed in practical applications, and the number of pyrometers is not limited in this embodiment.

[0039] In step 103, it is determined whether the first fluctuation value is less than or equal to a preset threshold. Assuming the preset threshold is set to 0.1, this step requires determining whether |max-min| is less than or equal to 0.1.

[0040] In step 104, the emissivity measured by a single pyrometer is designated as the common emissivity and used for temperature calculations of all pyrometers. In this step, if |max-min|≤0.1, it indicates that the emissivity on the back side of the wafer is relatively uniform. Therefore, a "global uniformity" strategy is adopted, that is, the emissivity measured by the designated single pyrometer is used for temperature calculations of all pyrometers. The single pyrometer designated as the source of the common emissivity in this step is the pyrometer located in the middle of the array of multiple pyrometers. For example, if seven pyrometers T1-T7 are arranged sequentially along the wafer radius from the wafer center to the wafer edge, then T4 is the pyrometer located in the middle of the array of all pyrometers. Therefore, the emissivity measured by T4 is designated as the common emissivity and used for temperature calculations of all pyrometers (i.e., T1-T7). This strategy simplifies calculations, reduces system overhead, and is particularly suitable for wafers with a uniform back side material (such as bare silicon), improving processing efficiency while maintaining accuracy.

[0041] In step 105, if the first fluctuation value is greater than a preset threshold, a second fluctuation value between the emissivity measured by adjacent pyrometers is calculated. Specifically, in this step, if |max-min|>0.1, it indicates that the emissivity on the back side of the wafer is not uniform. At this time, the second fluctuation value between the emissivity measured by adjacent thermometers (e.g., T1 and T2; T2 and T3, T3 and T4, etc.) is calculated respectively. This second fluctuation value is also determined by calculating the absolute difference between the emissivity measured by two adjacent thermometers.

[0042] In step 106, it is determined whether the second fluctuation value is less than a preset threshold.

[0043] In step 107, adjacent pyrometers with a second fluctuation value less than a preset threshold are grouped together, and a representative pyrometer is designated within each group. The emissivity measured by this representative pyrometer is used to calculate the temperature at the corresponding location of all pyrometers within the group. In this step, assuming the second fluctuation value between adjacent thermometers T1 and T2 is less than the preset threshold, T1 and T2 are grouped together. If the second fluctuation value between T2 and T3 is also less than the preset threshold, T3 can be first grouped into the same group as T1 and T2. At the same time, the overall fluctuation value of T1, T2, and T3 is recalculated (similar to step 102). If the overall fluctuation value is also less than the preset threshold, then T1, T2, and T3 are formally grouped together. Then, the second fluctuation values ​​of T3 and T4 are determined. This process is repeated to group all pyrometers, with the grouping principle being that the emissivity fluctuation value measured by all pyrometers within each group is less than the preset threshold. Then, a representative pyrometer is designated within each group, and the emissivity measured by this representative pyrometer is used to calculate the temperature at the corresponding location of all pyrometers within the group. This means that the pyrometer can be a pyrometer that is closer to the center of the wafer within each group.

[0044] In this step, if the second fluctuation value is not less than the preset threshold, then proceed to step 108 to group the adjacent pyrometers individually.

[0045] In step 108, adjacent pyrometers are grouped together, and the temperature at the corresponding location of each pyrometer is calculated based on the emissivity measured by each pyrometer.

[0046] In this step, when grouping, if a pyrometer located at the edge of the wafer (e.g., T7) is grouped separately, the emissivity measured by that separate pyrometer is processed to filter out periodic noise related to wafer rotation, and then the processed emissivity is used to calculate the temperature at the corresponding location of that pyrometer.

[0047] The grouping strategy in this application ensures that the emissivity used at each temperature calculation point best represents the actual value of its local area, fundamentally eliminating temperature measurement inaccuracies caused by spatial differences in emissivity. Special processing of edge points effectively suppresses signal interference caused by wafer rotation, further improving the stability and accuracy of temperature measurement in edge regions.

[0048] In step 109, based on the calculated wafer temperatures at multiple locations, the heating zones of the heating lamp assembly are controlled to perform zoned temperature control on the wafer.

[0049] Preferably, in this embodiment of the application, before using multiple pyrometers to simultaneously measure the thermal radiation intensity and emissivity at corresponding locations on the back side of the wafer, the current wafer's recipe information can be read first. This recipe information may include heating temperature, heating time, heating gas, the number and distribution of heating areas, and the material deposited on the wafer surface. Then, it is determined whether the recipe information specifies process matching requirements. If process matching requirements are specified, the number of heating lamp groups participating in wafer heating, the number and distribution of pyrometers participating in emissivity measurement, and the number and distribution of pyrometers participating in temperature control are set according to a preset matching mode. If there are no preset process matching requirements in the recipe information, the system uses the default optimal wafer heating method (e.g., using 15 zones to heat the wafer and using 7 pyrometers to participate in temperature measurement and control).

[0050] The embodiments of this application have the following advantages compared to the prior art:

[0051] 1. By independently and synchronously measuring the emissivity of each local point using each pyrometer, the error of "representing the whole area by a single point" is avoided, achieving true point-to-point accurate temperature measurement. This fundamentally solves the temperature measurement error caused by uneven spatial distribution of emissivity.

[0052] 2. By calculating the emissivity fluctuation value and dynamically selecting the "global uniformity" or "group calculation" strategy, it can efficiently process wafers with uniform emissivity (such as bare silicon wafers) and accurately handle wafers with non-uniform emissivity (such as products with different thin films deposited on the back), achieving the best balance between ensuring accuracy and ensuring calculation efficiency.

[0053] 3. Accurate temperature measurement is a prerequisite for accurate temperature control. This application provides more realistic wafer temperature field information, enabling the multi-zone heating control system to provide more accurate feedback, thereby greatly improving the temperature uniformity within the wafer and the repeatability of inter-wafer processes, and significantly improving process consistency and yield.

[0054] 4. By using "recipe information" to drive equipment configuration (such as the number of heating zones, activated pyrometers, etc.), different models of RTP equipment can simulate similar thermal budgets when performing the same process, achieving cross-platform process matching and improving product adaptability.

[0055] This application also provides a semiconductor thermal processing apparatus, such as... Figure 2 As shown, it includes: a reaction chamber 14; a support mechanism 12 for supporting and rotating the wafer 13; a heating lamp assembly 11 located above the wafer 13 for heating the wafer 13, the heating lamp assembly 11 being divided into multiple independently controllable heating zones; multiple pyrometers disposed below the wafer 13, each corresponding to a multiple measurement point on the back side of the wafer 13; and a control system communicatively connected to the heating lamp assembly and the multiple pyrometers, configured to execute the above-described method.

[0056] In this embodiment, the pyrometer can be fixed inside the reaction chamber 14 via the connecting component 1, and the control system and the pyrometer can be connected via the communication cable 7, realizing information exchange between the pyrometer and the control system. The support mechanism 12 may include: a rotatable wafer support ring 121 and a liftable support pin 122.

[0057] The heating lamp group 11 is divided into multiple controllable heating zones. Each lamp group can be divided into multiple zones centered on the central axis of the wafer 13, such as... Figure 2 and Figure 3 As shown, the heating lamp assembly can have a maximum of 15 heating zones, such as... Figure 2 The diagram shows seven regions: Z1, Z2, Z3, Z4, Z5, Z6, and Z7, and these regions are individually controlled. The pyrometer can have up to seven measurement points, such as pyrometers T1, T2, T3, T4, T5, T6, and T7, each corresponding to a wafer 13 below multiple heating regions for measurement. The device is configured to perform independent closed-loop temperature control on the corresponding heating region based on the temperature measured by each probe.

[0058] Under standard rapid annealing process conditions, such as low pressure of 1–760 Torr, process temperature of 180–1200°C, and process gases containing oxygen, nitrogen, ammonia, oxygen and nitrogen, or oxygen and hydrogen, the total gas flow rate is 1–60 slm. The wafer 13, conveyed into the reaction chamber 14, is supported by support pins 122, positioning it directly above the wafer support ring 121. The heating lamp assembly 11 above the wafer 13 and wafer support ring 121 initially heats the wafer 13 and wafer support ring 121 at a predetermined open-loop power (e.g., 5%–20%). During the initial open-loop heating time (e.g., 5-8 seconds), the temperature and heating rate of the wafer support ring 121 are measured using a second pyrometer at the second measuring point. Based on the open-loop heating power of the heating lamp group 11 above the wafer 13 and the temperature and heating rate of the wafer support ring 121, the open-loop heating power of the heating lamp group 11 above the wafer support ring 121 is automatically adjusted so that the temperature difference between the wafer support ring 121 and the wafer 13 is less than a set value (e.g., 30°C). When the temperature of the wafer 13 and the wafer support ring 121 reach a preset value (e.g., 200°C), the support pin 122 descends, the wafer 13 contacts the wafer support ring 121, and the wafer support ring 121 begins to rotate. The pyrometer measures temperatures T1, T2, T3, T4, T5, T6, and T7, and temperature control is performed in seven regions Z1, Z2, Z3, Z4, Z5, Z6, and Z7. The wafer then enters the closed-loop heating step.

[0059] This embodiment integrates a pyrometer into the heat treatment equipment, enabling precise closed-loop control of the wafer temperature from the initial open-loop heating to the final process temperature. Particularly in multi-zone heating systems, it provides independent and accurate temperature feedback for each heating zone. More precise wafer temperature measurement facilitates more accurate temperature control, significantly improving temperature uniformity within the wafer, reducing wafer warpage caused by thermal stress, and ultimately enhancing process stability and production yield.

[0060] The pyrometer in this embodiment includes an active emissivity measurement module, a temperature measurement module, and a logic circuit. The active emissivity measurement module is used to emit detection light to the wafer and receive its reflected light to calculate the emissivity. The temperature measurement module is used to receive the thermal radiation light from the wafer to calculate the temperature based on the emissivity. The logic circuit is used to receive signals from the active emissivity measurement module and the temperature measurement module, and calculate the emissivity and temperature of the wafer based on the signals. The active emissivity measurement module and the temperature measurement module share at least some optical path components.

[0061] Specifically, in one alternative embodiment, such as Figure 4 and Figure 5As shown, the active emissivity measurement module includes: a pulsed light source 201, a first photodetector 204, a beam splitter 203, a second photodetector 304, a light guide element 4, a first reflector 301, a second reflector 303, a first filter 202, and a second filter 302.

[0062] The pulsed light source 201 is preferably an infrared LED light source used to emit pulsed light of a specific wavelength; its operating wavelength range is 800nm-1000nm, more preferably 800nm-920nm. The light source is driven to emit modulated pulsed light with a fixed frequency.

[0063] The first filter 202 is positioned after the pulse light source 201 and between the pulse light source 201 and the beam splitter 203. It is used to purify the emitted light, ensuring that only pulse light of a specific wavelength enters the system and suppressing stray light.

[0064] Beam splitter 203 is disposed in the pulsed light path to reflect part of the pulsed light back to the wafer and transmit the reflected light returning from the wafer to the second photodetector 304.

[0065] The first photodetector 204 receives a portion of the pulsed light transmitted from the beam splitter 203 to monitor the light output state (such as light output intensity and stability) of the pulsed light source, serving as a reference signal for subsequent calculations.

[0066] The first reflector 301 is used to reflect and rectify the pulsed light from the beam splitter 203 onto the light guide element 4, and to rectify the light received by the light guide element 4 from the thermal radiation of the wafer.

[0067] The light guide element 4 is preferably a quartz light guide, which has good infrared transmission performance and thermal stability. It is used to guide the pulsed light to and from the wafer. The second reflector 303 is used to reflect and bundle the reflected light from the beam splitter 203 to the second photodetector 304. Specifically, the light guide element 4 guides the pulsed light to the test position on the back side of the wafer within the reaction chamber 14. The pulsed light reflected back from the back side of the wafer passes through the light guide element 4 and the first reflector 301 again, is transmitted through the beam splitter 203, and is reflected by the second reflector 303.

[0068] The second filter 302 is disposed between the beam splitter 203 and the second reflector 303 in the reflected light path to filter out background stray light and ensure that only signals in the pulse light band are received by the detector.

[0069] The second photodetector 304 receives the reflected pulse light returning from the wafer, which is reflected by the second reflector 303.

[0070] In this embodiment, the logic circuit calculates the reflectivity of the wafer by comparing the pulse light intensity information received by the first photodetector 204 and the second photodetector 304, and then calculates the emissivity.

[0071] In an alternative embodiment, reference is made to... Figure 5 The logic circuit also includes a photoelectric component module 5 and an I / O and logic circuit module 6. The photoelectric component module 5 includes analog front-ends of a first photodetector 204 and a second photodetector 304, used to receive light signals and convert them into electrical signals; the I / O and logic circuit module 6 is configured to calculate the temperature by comparing the pulse light intensity information received by the first photodetector 204 and the second photodetector 304, and to realize a data communication interface with external devices and receive external configuration commands.

[0072] The optoelectronic component module 5 also includes a light source driving unit for driving the pulse light source 201 to emit pulse light at a predetermined frequency and duty cycle.

[0073] In this embodiment, both the first filter 202 and the second filter 302 can be infrared bandpass filters, and both the first photodetector 204 and the second photodetector 304 can be photodiodes. When using the pyrometer of this embodiment to detect temperature and emissivity, the pulse light source 201 emits pulse light with a fixed frequency. After being filtered by the first filter 202, the pulse light passes through the beam splitter 203. A portion of the pulse light passes through the beam splitter 203 and illuminates the first photodetector 204, which monitors the operating status of the pulse light source 201. Another portion of the pulse light is reflected by the beam splitter 203, passes through the first reflector 301 and the light guide element 4, and finally illuminates the emissivity measurement location on the back of the wafer. The pulse light illuminating the back of the wafer is reflected back by the wafer and re-intruded into the light guide element 4. After passing through the first reflector 301, the beam splitter 203, and the second filter 302, it is received by the second photodetector 304 after passing through the second reflector 303. The pulse light intensity information measured by the second photodetector 304 and the first photodetector 204 is processed to obtain the infrared light reflectance on the back side of the wafer, and then the emissivity of the wafer is calculated through the emissivity.

[0074] In this embodiment, the temperature measurement module and the active emissivity measurement module can share the optical guide element 4, the first reflector 301, the beam splitter 203, the second filter 302, the second reflector 303, and the second photodetector 304. The thermal radiation light from the wafer passes sequentially through the optical guide element 4, the first reflector 301, the beam splitter 203, the second filter 302, and the second reflector 303, and is received by the second photodetector 304. The logic circuit combines the measured emissivity and thermal radiation intensity to calculate the wafer temperature using the blackbody radiation formula.

[0075] Preferably, the optical centers of the light guide element 4, the first reflector 301, the beam splitter 203, the second filter 302, and the second photodetector 304 are located on a first straight line, forming the main optical path; while the optical centers of the pulsed light source 201, the first filter 202, the beam splitter 203, and the first photodetector 204 are located on a second straight line; the first straight line and the second straight line are perpendicular to each other. This "T"-shaped or "L"-shaped optical path layout makes the structure very compact, stable, and easy to assemble and calibrate.

[0076] The logic circuit in this embodiment receives a reference signal from the first photodetector 204 and a reflected signal from the second photodetector 304. Since the reflected signal is very weak and mixed with the thermal radiation background noise of the wafer, the signal processing unit in the logic circuit (which can be a lock-in amplifier, a Boxcar averager, or a resonant amplifier) ​​is used to extract the intensity of the pulsed light from the signal from the second photodetector 304. By comparing the reference signal and the extracted reflected signal, the reflectivity of the wafer's back surface for that wavelength of light can be calculated. According to Kirchhoff's law of thermal radiation, its emissivity It can be done through formula The calculation yielded that, For opaque or nearly opaque wafers, τ is the transmittance (τ ≈ 0).

[0077] Substituting the emissivity ε obtained from the previous calculation into the blackbody radiation formula:

[0078]

[0079] Among them, among them, Let λ be the thermal radiation intensity of an object at temperature T at the detection wavelength λ. To detect wavelength, The temperature of the object. is Planck's constant. At the speed of light, This is Boltzmann's constant. Logic circuits can calculate the true temperature of the wafer by solving this equation. .

[0080] In this embodiment, while the active emissivity measurement module is operating, the continuous-spectrum infrared light emitted by the wafer's own thermal radiation is transmitted in reverse along the same shared optical path as the reflected pulse light: that is, sequentially passing through the optical guide element 4, the first reflector 301, the beam splitter 203, the second filter 302, and the second reflector 303, and finally received by the second photodetector 304. The second photodetector 304 sends the received total light intensity signal (including DC thermal radiation signal and AC reflected pulse signal) to the logic circuit. The logic circuit first uses the signal processing unit to extract the AC reflected pulse signal (for emissivity calculation). At the same time, it also measures the DC component in the total signal, which represents the thermal radiation intensity of the wafer in this band. Substituting the calculated emissivity ε and the measured thermal radiation intensity into the blackbody radiation formula, the true temperature T of the wafer can be calculated. Since the emissivity ε and thermal radiation intensity are measured synchronously and along the same path, they can be perfectly matched and substituted into the blackbody radiation formula to calculate an accurate temperature value.

[0081] Compared to existing technologies, this application integrates an active emissivity measurement module, a temperature measurement module, and logic circuitry, combining emissivity and temperature measurement functions into a single probe and sharing most optical path components. This not only simplifies the system structure and reduces cost and maintenance difficulty, but also breaks the traditional need for two separate devices (one for emissivity and one for temperature). It ensures that emissivity and thermal radiation intensity are measured from the exact same physical location and optical path, fundamentally eliminating system errors caused by measurement position deviations or optical path differences, significantly improving the accuracy and reliability of temperature calculations. By actively emitting pulsed light, it breaks the traditional dependence on the wafer's own thermal radiation intensity, making it possible to accurately measure emissivity from room temperature. Employing techniques such as lock-in amplification greatly suppresses background noise, enabling the extraction of weak reflected pulse signals from a strong thermal radiation background, ensuring measurement accuracy under low signal-to-noise ratio conditions. By sharing the optical path, it ensures coaxial and common-path measurements of emissivity and thermal radiation intensity, measuring the true physical state of the same point, eliminating system errors.

[0082] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0083] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0084] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A temperature measurement and control method for a semiconductor thermal processing process, characterized by, A method applied to a thermal processing apparatus, the thermal processing apparatus comprising a heating lamp set divided into a plurality of heating zones, and a plurality of pyrometers corresponding to a plurality of measurement sites on the backside of a wafer, the method comprising the steps of: synchronously measuring the thermal radiation intensity and emissivity of the corresponding positions on the backside of the wafer by the plurality of pyrometers; calculating a first fluctuation value of the emissivity measured by the plurality of pyrometers, the first fluctuation value being the absolute value of the difference between the maximum and minimum of the emissivity measured by the plurality of pyrometers; if the first fluctuation value is less than or equal to a preset threshold value, designating the emissivity measured by one of the plurality of pyrometers as a common emissivity for temperature calculation of all the pyrometers; if the first fluctuation value is greater than the preset threshold value, calculating a second fluctuation value between the emissivity measured by adjacent pyrometers, and grouping the adjacent pyrometers with the second fluctuation value less than the preset threshold value into the same group, and designating one representative pyrometer in each group, and using the emissivity measured by the representative pyrometer to calculate the temperature of the corresponding positions of all the pyrometers in the group, the second fluctuation value being the absolute difference between the emissivity measured by adjacent pyrometers; controlling the heating zones of the heating lamp set to perform zonal temperature control on the wafer according to the calculated wafer temperature at a plurality of positions.

2. The method of claim 1, wherein, The method further comprises, before the step of synchronously measuring the thermal radiation intensity and emissivity of the corresponding positions on the backside of the wafer by the plurality of pyrometers: reading recipe information of the current wafer; determining whether a process matching requirement is designated in the recipe information; if the process matching requirement is designated, setting the number of heating lamp set zones participating in wafer heating, the number and distribution of pyrometers participating in emissivity measurement, and the number and distribution of pyrometers participating in temperature control according to a preset matching mode.

3. The method of claim 1, wherein, In the grouping step, if a pyrometer located at the edge of the wafer is separately grouped into a group, the emissivity measured by the pyrometer is subjected to signal processing to filter out periodic noise related to wafer rotation, and the processed emissivity is used for temperature calculation of the corresponding position of the pyrometer.

4. The method of claim 1, wherein, The one of the plurality of pyrometers designated as the source of the common emissivity is a pyrometer located at the middle position of the array of the plurality of pyrometers. And / or, the representative pyrometer is the pyrometer closer to the center of the wafer in each group.

5. A semiconductor heat treatment apparatus, characterized by comprising: The thermal processing apparatus comprises: a reaction chamber; a support mechanism for supporting and rotating the wafer; a heating lamp set located above the wafer for heating the wafer, the heating lamp set being divided into a plurality of independently controllable heating zones; a plurality of pyrometers arranged below the wafer and corresponding to a plurality of measurement sites on the backside of the wafer; a control system in communication with the heating lamp set and the plurality of pyrometers, and configured to perform the method of any one of claims 1-4.

6. The apparatus of claim 5, wherein, The pyrometer comprises: an active emissivity measurement module for emitting detection light to the wafer and receiving the reflected light to calculate the emissivity; a temperature measurement module for receiving the thermal radiation light of the wafer to calculate the temperature; a logic circuit for receiving signals of the active emissivity measurement module and the temperature measurement module, and calculating the emissivity and temperature according to the signals. The active emissivity measurement module and the temperature measurement module share at least part of the optical path elements.

7. The apparatus of claim 6, wherein, The active emissivity measurement module comprises: a pulsed light source for emitting pulsed light of a specific wavelength; a first photodetector for monitoring the light emission state of the pulsed light source; a beam splitter arranged in the optical path of the pulsed light source for reflecting part of the pulsed light to the wafer and transmitting the reflected light returned from the wafer to a second photodetector; a light guide element for guiding light to and receiving light from the wafer; a first mirror for reflecting the pulsed light from the beam splitter to the light guide element and reflecting the light received by the light guide element from the thermal radiation of the wafer; a second mirror for reflecting the reflected light from the beam splitter to the second photodetector; a first filter arranged between the pulsed light source and the beam splitter; a second filter arranged between the beam splitter and the second mirror, the first filter and the second filter being used to select light of a specific wavelength band; The logic circuit is configured to calculate the reflectivity of the wafer by comparing the intensity information of the pulsed light received by the first photodetector and the second photodetector, and then calculate the emissivity.

8. The apparatus of claim 6, wherein, The logic circuit combines the measured emissivity and the intensity of the thermal radiation to calculate the temperature of the wafer by the blackbody radiation formula.

9. The apparatus of claim 7, wherein, The temperature measurement module and the active emissivity measurement module share the light guide element, the first mirror, the beam splitter, the second filter, the second mirror, and the second photodetector. The thermal radiation light of the wafer passes through the light guide element, the first mirror, the beam splitter, the second filter, and the second mirror in sequence and is received by the second photodetector.

10. The apparatus of claim 8, wherein, The emissivity By formula is calculated, where, is the transmittance, is the reflectance; The blackbody radiation formula is represented as: wherein, is the thermal radiation intensity of an object at a temperature T at a detection wavelength λ, is the detection wavelength, is the temperature of the object, is Planck's constant, is the speed of light, is the Boltzmann constant.

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