Wireless wafer temperature measurement system and temperature measurement method

Abstract

The invention discloses a wireless wafer temperature measurement system and a temperature measurement method, and relates to the technical field of semiconductor manufacturing. The wireless wafer temperature measurement system comprises a temperature measurement device and a signal control and processing device, the temperature measurement device comprises two wafers, a surface acoustic wave sensor array and a first antenna, and the signal control and processing device comprises a second antenna, an output unit, a radio frequency signal generator and a signal demodulator; the radio frequency signal generator is used for transmitting excitation signals with different frequencies to the surface acoustic wave sensors according to a time sequence through the antenna, and the signal demodulator is used for receiving echo signals of the surface acoustic wave sensors according to the time sequence through the antenna and determining the temperature of the surface acoustic wave sensors according to the frequency difference between the echo signals and the excitation signals and the mapping relation between the preset frequency difference and the temperature. And the output unit is used for generating a temperature field image according to the temperature of the corresponding position of each surface acoustic wave sensor and displaying the temperature field image. By adopting the system, continuous and real-time temperature measurement can be realized, and the production efficiency is greatly improved.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and particularly to a wireless wafer temperature measurement system and a temperature measurement method. Background Art

[0002] In the manufacturing process of semiconductor chips, it is becoming increasingly important to accurately monitor the wafer temperature, which can help process engineers complete tasks such as adjusting etching conditions, verifying and matching the cavity, ensuring process stability, and improving the product yield.

[0003] Currently, the related technology mainly uses wireless wafer temperature measurement, that is, after the data is read, it is sent to an external receiving device through wireless communication technology to process and obtain the temperature value. The temperature sensing elements in this way include thin-film thermistors and integrated circuit type temperature sensors, etc., but they all need to be powered by a battery at the sensor end. Limited by the battery capacity, they cannot work continuously for a long time, which directly affects the production efficiency of semiconductor manufacturing. Moreover, the data can only be read by a reader after the temperature measurement is completed, and the real-time performance of temperature measurement is poor. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the related technology, it is expected to provide a wireless wafer temperature measurement system and a temperature measurement method, which can continuously and real-time measure the temperature and improve the production efficiency of semiconductor manufacturing.

[0005] In a first aspect, this application provides a wireless wafer temperature measurement system, and the wireless wafer temperature measurement system includes: A temperature measurement device, the temperature measurement device includes two wafers, a surface acoustic wave sensor array disposed between the two wafers, and a first antenna connected to the surface acoustic wave sensor array. The excitation signal frequencies of the surface acoustic wave sensors in the surface acoustic wave sensor array are different; A signal control and processing device, the signal control and processing device includes a second antenna, an output unit, a radio frequency signal generator and a signal demodulator connected to the second antenna. The output unit is connected to the signal demodulator; the radio frequency signal generator is used to sequentially transmit different frequency excitation signals to the surface acoustic wave sensors through the second antenna and the first antenna; the signal demodulator is used to sequentially receive the echo signals of the surface acoustic wave sensors through the first antenna and the second antenna, and determine the temperature at the corresponding position of each surface acoustic wave sensor according to the frequency difference between the echo signal and the excitation signal and the mapping relationship between the preset frequency difference and the temperature; the output unit is used to generate a temperature field image according to the temperature at the corresponding position of each surface acoustic wave sensor and display the temperature field image.

[0006] Optionally, in some embodiments of the present application, the surface acoustic wave sensor includes a piezoelectric substrate, and a first reflection grating, an interdigital transducer, and a second reflection grating that are sequentially arranged on the piezoelectric substrate, and the interdigital periods of the interdigital transducers in each surface acoustic wave sensor are different.

[0007] Optionally, in some embodiments of the present application, the piezoelectric substrate includes a lithium niobate substrate, an aluminum nitride substrate, and a lithium tantalate substrate.

[0008] Optionally, in some embodiments of the present application, the interdigital transducer includes a first interdigital electrode and a second interdigital electrode that are alternately arranged, and each interdigital electrode is provided with a bus bar.

[0009] Optionally, in some embodiments of the present application, the interdigital width of the interdigital transducer is equal to the interdigital pitch, and both are 1 / 4 of the interdigital period.

[0010] Optionally, in some embodiments of the present application, the aperture width range of the interdigital transducer is 100 times to 1000 times the interdigital period.

[0011] Optionally, in some embodiments of the present application, the first antenna is a rectangular microstrip antenna, the patch length of the rectangular microstrip antenna is 32 mm, the patch width is 22 mm, and the feeding method is 50Ω microstrip line feeding, and the feeder width is 2.5 mm.

[0012] Optionally, in some embodiments of the present application, the second antenna is a horn antenna, the waveguide length in the horn antenna is 156.25 mm, the waveguide width is 62.5 mm, the waveguide height is 31.25 mm, and the horn mouth length is 300 mm, the horn mouth width is 250 mm, and the horn mouth height is 125 mm.

[0013] Optionally, in some embodiments of the present application, the operating main frequencies of the first antenna and the second antenna are both 2.4 GHz, and the bandwidth is ±0.5 GHz.

[0014] In a second aspect, the present application provides a method for wireless wafer temperature measurement. The method for wireless wafer temperature measurement is used for the wireless wafer temperature measurement system described in any one of the first aspects. The method for wireless wafer temperature measurement includes: Sequentially transmitting excitation signals with different frequencies to each surface acoustic wave sensor; Sequentially receiving the echo signals of the surface acoustic wave sensors, and determining the temperature at the corresponding position of each surface acoustic wave sensor according to the frequency difference between the echo signal and the excitation signal and the mapping relationship between the preset frequency difference and the temperature; Generating a temperature field image according to the temperature at the corresponding position of each surface acoustic wave sensor, and displaying the temperature field image.

[0015] As can be seen from the above technical solutions, the embodiments of the present application have the following advantages: The embodiments of the present application provide a wireless wafer temperature measurement system and a temperature measurement method. The second antenna and the first antenna sequentially transmit excitation signals with different frequencies to each surface acoustic wave sensor in the surface acoustic wave sensor array to cause each surface acoustic wave sensor to work in sequence. Since the surface acoustic wave sensor has a piezoelectric effect, when the temperature changes, the elastic constant and density of the piezoelectric material change accordingly, and the propagation speed of the surface acoustic wave in the sensor changes, which will cause a frequency shift. Thus, the first antenna and the second antenna can sequentially receive the echo signals of each surface acoustic wave sensor, and based on the frequency difference between the echo signal and the excitation signal and the mapping relationship between the preset frequency difference and the temperature, quickly determine the temperature at the corresponding position of each surface acoustic wave sensor. It does not require battery power supply and is not limited by the battery capacity, and can continuously and real-time measure the temperature. Furthermore, after generating a temperature field image based on the temperature at the corresponding position of each surface acoustic wave sensor, it is visually displayed, clearly presented at a glance, greatly improving the production efficiency of semiconductor manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1 is a structural block diagram of a wireless wafer temperature measurement system provided by an embodiment of the present application; Figure 2 is a schematic diagram of timing control provided by an embodiment of the present application; Figure 3 is a top view of a surface acoustic wave sensor provided by an embodiment of the present application; Figure 4 is a Figure 3 front view of the surface acoustic wave sensor shown in the present application embodiment; Figure 5 is a structural schematic diagram of an interdigital transducer provided by an embodiment of the present application; Figure 6 is a structural schematic diagram of a first antenna provided by an embodiment of the present application; Figure 7 is a structural schematic diagram of a second antenna provided by an embodiment of the present application; Figure 8 is a Figure 7 left view of the second antenna shown in the present application embodiment; Figure 9 is aFigure 7 Top view of the second antenna shown Figure 10 A kind provided by an embodiment of the present application Figure 7 Front view of the second antenna shown Figure 11 Schematic diagram of the manufacturing process of a temperature measurement device with a three - layer structure provided by an embodiment of the present application Figure 12 Schematic diagram of the manufacturing process of a temperature measurement device with a two - layer structure provided by an embodiment of the present application Figure 13 Schematic flow chart of a wireless wafer temperature measurement method provided by an embodiment of the present application

[0018] Reference signs: 1 - Wireless wafer temperature measurement system, 11 - Temperature measurement device, 111 - Wafer, 112 - Surface acoustic wave sensor array, 1121 - Surface acoustic wave sensor, a - Piezoelectric substrate, b - First reflection grating, c - Interdigital transducer, c1 - First interdigital electrode, c2 - Second interdigital electrode, c3 - Bus bar, c4 - Interdigital width, c5 - Interdigital pitch, c6 - Aperture width, d - Second reflection grating, P - Interdigital period, 113 - First antenna, e1 - Patch length, e2 - Patch width, e3 - Feeder width, 12 - Signal control and processing device, 121 - Second antenna, g1 - Waveguide length, g2 - Waveguide width, g3 - Waveguide height, g4 - Flare length, g5 - Flare width, g6 - Flare height, 122 - Output unit, 123 - Radio frequency signal generator, 124 - Signal demodulator. Detailed implementation manners

[0019] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0020] To make the above - mentioned objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below in conjunction with the drawings and specific implementation manners.

[0021] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. Next, Figures 1 to 13 The wireless wafer temperature measurement system and temperature measurement method provided by the embodiments of the present application will be elaborated in detail.

[0022] Please refer to Figure 1, which is a structural block diagram of a wireless wafer temperature measurement system provided by an embodiment of the present application. The wireless wafer temperature measurement system 1 includes a temperature measurement device 11 and a signal control and processing device 12. The temperature measurement device 11 includes, but is not limited to, two wafers 111, a surface acoustic wave sensor array 112 disposed between the two wafers 111, a first antenna 113 connected to the surface acoustic wave sensor array 112, etc. The excitation signal frequencies of the surface acoustic wave sensors 1121 in the surface acoustic wave sensor array 112 are different. The signal control and processing device 12 includes, but is not limited to, a second antenna 121, an output unit 122, a radio frequency signal generator 123 and a signal demodulator 124 connected to the second antenna 121, etc. The output unit 122 is connected to the signal demodulator 124.

[0023] During actual temperature measurement, the radio frequency signal generator 123 can sequentially transmit different frequency excitation signals to each surface acoustic wave sensor 1121 through the second antenna 121 and the first antenna 113. The signal demodulator 124 can sequentially receive the echo signals of each surface acoustic wave sensor 1121 through the first antenna 113 and the second antenna 121, that is, as Figure 2 shown in the time-division multiplexing control method, the signal transmission and reception of each surface acoustic wave sensor 1121 are carried out in different time periods, effectively avoiding signal interference. For example, the transmission period T 发 ≤10 ms, and the reception period T 收 ≤10 ms. Furthermore, the signal demodulator 124 can also quickly determine the temperature of the corresponding position of each surface acoustic wave sensor 1121 according to the frequency difference between the echo signal and the excitation signal and the mapping relationship between the preset frequency difference and the temperature. It should be noted that the mapping relationship includes, but is not limited to, function curves and two-dimensional tables, etc., which can be obtained through experimental data. The distribution positions of each surface acoustic wave sensor 1121 are calibrated at the factory, covering the entire wafer surface area. Finally, the output unit 122 can generate a temperature field image according to the temperature of the corresponding position of each surface acoustic wave sensor 1121 and visually display the temperature field image, which is clear at a glance. For example, through an interpolation algorithm for smoothing and continuity, a two-dimensional temperature field of the entire wafer surface area is reconstructed, and a two-dimensional color thermal map can be displayed.

[0024] In some embodiments of the present application, such as Figures 3 to 5As shown in the figure, the surface acoustic wave sensor 1121 includes a piezoelectric substrate a, and a first reflection grating b, an interdigital transducer c, and a second reflection grating d that are sequentially arranged on the piezoelectric substrate a. The interdigital transducer c can realize the "electrical - acoustic" mutual conversion between electromagnetic waves and surface acoustic waves. At the same time, the first reflection grating b and the second reflection grating d can reflect the surface acoustic waves and form resonance between these two reflection gratings, and the interdigital period P of the interdigital transducer c in each surface acoustic wave sensor 1121 is different. Specifically, when an external excitation electrical signal is input to the interdigital transducer c, due to the existence of the inverse piezoelectric effect, the piezoelectric substrate a generates periodic elastic deformation, converting the input radio signal into an acoustic signal, thereby exciting a surface acoustic wave and propagating on the surface of the piezoelectric substrate a. When the surface acoustic wave propagates to the reflection gratings on both sides, it is reflected back into the interdigital transducer c through the reflection gratings and is superimposed and enhanced in the reflection gratings to form resonance. Then, due to the existence of the direct piezoelectric effect, the resonated acoustic signal generates a periodic alternating electric field between the grating bars in the interdigital transducer c again, and the surface acoustic wave is converted back into an electrical signal for output, completing the conversion of electrical - acoustic - electrical signals and the energy conversion of electrical energy - mechanical energy - electrical energy. Finally, the converted electrical signal is responded to through the first antenna 113, realizing the wireless sensing function.

[0025] Further, for example, the piezoelectric substrate a includes, but is not limited to, lithium niobate (LiNbO3) substrate, aluminum nitride (AlN) substrate, lithium tantalate (LiTaO3) substrate, etc. Another example Figure 5 As shown in the figure, the interdigital transducer c includes, but is not limited to, a first interdigital electrode c1 and a second interdigital electrode c2 that are alternately arranged, etc., and each interdigital electrode is provided with a bus bar c3. The excitation signal frequency of the surface acoustic wave sensor 1121 is generally determined by the characteristic frequency f 0 of the interdigital transducer c, that is: f 0 = v / P (1) In formula (1), v represents the wave velocity of the surface acoustic wave, which is related to the elastic constant and density of the piezoelectric substrate material. For lithium niobate material, the wave velocity v ranges from 3000 m / s to 4000 m / s. Due to the anisotropy of the lithium niobate material, the specific wave velocity value is related to the propagation direction in the crystal. Once the propagation direction is determined, the specific wave velocity value is determined. It can be seen from formula (1) that the characteristic frequency f 0 of the interdigital transducer c is inversely proportional to the interdigital period P. In the embodiments of the present application, the interdigital width c4 of the interdigital transducer c is equal to the interdigital spacing c5, and both are 1 / 4 of the interdigital period P, thereby exciting a surface acoustic wave with a corresponding frequency.

[0026] The aperture width c6 is related to the magnitude of the frequency offset. The larger the aperture width c6, the smaller the frequency offset. In the embodiments of the present application, the range of the aperture width c6 of the interdigital transducer c can be 100 times to 1000 times the interdigital period P, and the range is appropriate. By designing interdigital transducers c with different interdigital periods for each surface acoustic wave sensor 1121, such as P1, P2,..., P n etc., so that they correspond to different characteristic frequencies, such as f 1, f 2,..., f n etc. Within a certain range, the frequency offset (Δ f ) of the surface acoustic wave sensor 1121 and the temperature change amount (Δ T ) show a monotonic linear relationship, that is, the temperature change amount and the frequency offset can be expressed as: Δ f = f 0· α ·Δ T (2) In formula (2), α represents the temperature coefficient, which is related to the material characteristics. For lithium niobate materials, the temperature coefficient α is -75 ppm / °C, the temperature coefficient of aluminum nitride material α is -25 ppm / °C, and the temperature coefficient of lithium tantalate material α is -30 ppm / °C. It can be seen that the absolute value of the temperature coefficient of lithium niobate material is larger, and the frequency offset caused by temperature change is also larger, which is suitable for high-precision temperature measurement. The theoretical sensitivity can reach ±0.1 °C, meeting the requirements of wafer temperature measurement accuracy. At the same time, the working temperature of lithium niobate material can reach above 1000 °C. The interdigital electrodes are processed on the lithium niobate substrate through deposition and photolithography processes, making the surface acoustic wave sensor 1121 have high-temperature resistance characteristics.

[0027] When measuring the temperature of the wafer, the surface acoustic wave sensor 1121 operates in the GHz frequency band, and the size of the interdigital period P is The frequency offset of the designed interdigital transducer c is of the order of magnitude, leaving enough margin to reach the MHz level, ensuring that the temperature measurement range can reach above 500°C. For example, the thickness of a single lithium niobate substrate material is ≤1mm, and the length×width is ≤10mm×5mm. For another example, the frequency spacing of each surface acoustic wave sensor 1121 is set to 10MHz. Assuming that 10 sensors are used to measure temperature at the same time, the characteristic frequencies of these sensors are 2.4GHz, 2.41GHz, 2.42GHz, 2.43GHz, 2.44GHz, 2.45GHz, 2.46GHz, 2.47GHz, 2.48GHz and 2.49GHz respectively. The interdigital transducer c is made by electron beam lithography technology. For the sensors with characteristic frequencies of 2.4GHz to 2.49GHz, the interdigital period P is 1.454 , 1.448 , 1.442 , 1.436 , 1.43 , 1.424 , 1.418 , 1.412 , 1.406 and 1.4 Currently, the wafer temperature measurement range for silicon-based semiconductor applications is ≤200°C, while new semiconductors such as silicon carbide require a higher temperature measurement range. Therefore, the temperature measurement range of the surface acoustic wave sensor 1121 in the embodiment of the present application is above 500°C, which can greatly expand the scope of application.

[0028] In some embodiments of the present application, Figure 6 As shown, the first antenna 113 can be a rectangular microstrip antenna, the patch length e1 of the rectangular microstrip antenna is 32mm, the patch width e2 is 22mm, and the feeding method is 50Ω microstrip line feeding, and the feed line width e3 is 2.5mm. The rectangular microstrip antenna is used to receive the excitation signal and radiate the output signal of the sensor. It should be noted that the number of rectangular microstrip antennas can be multiple, that is, each surface acoustic wave sensor 1121 is integrated with a rectangular microstrip antenna, or the number of rectangular microstrip antennas can also be one, that is, each surface acoustic wave sensor 1121 shares a rectangular microstrip antenna, and through time division multiplexing, mutual interference between signals is avoided. The working main frequency of the rectangular microstrip antenna is 2.4GHz, and the bandwidth is ±0.5GHz. Further, as Figures 7 to 10As shown, the second antenna 121 can be a horn antenna. In this horn antenna, the waveguide length g1 is 156.25 mm, the waveguide width g2 is 62.5 mm, the waveguide height g3 is 31.25 mm, the horn mouth length g4 is 300 mm, the horn mouth width g5 is 250 mm, and the horn mouth height g6 is 125 mm. The advantage of such a setting is good directivity, which improves the signal transmission quality. The working main frequency of the horn antenna is 2.4 GHz, and the bandwidth is ±0.5 GHz.

[0029] In some embodiments of the present application, the structure of the temperature measurement device 11 includes, but is not limited to, the following double-layer structure, three-layer structure, etc. It has excellent repeatability and consistency, is convenient for mass production, and has low cost. For example Figure 11 As shown in the three-layer structure, during manufacturing, first, a silicon wafer is used as the bottom wafer, and grooves or blind holes are processed on this bottom wafer. Their shapes and depths are consistent with the thin film layer of the integrated surface acoustic wave sensor array 112. Then, the thin film layer is tightly bonded to the bottom wafer, and glue is filled in the gaps for sealing the circuit. Finally, a silicon wafer is covered on the top as the top wafer, and the two silicon wafers are sealed and bonded using high-temperature-resistant glue or bonded together through a bonding process. The thickness of the temperature measurement device 11 after bonding is 1 mm to 2 mm. The outer dimensions of the bottom wafer and the top wafer in the temperature measurement device 11 are the same as those of the semiconductor wafer to be processed. For example, the diameter of the semiconductor wafer can be 6 inches, 8 inches, 12 inches, etc.

[0030] Another example Figure 12 As shown in the double-layer structure, during manufacturing, first, a silicon wafer is used as the bottom wafer, and then the surface acoustic wave sensor array 112 is directly integrated on this bottom wafer through the processing technology of microelectromechanical systems, that is, there is no thin film layer. Finally, similarly, a silicon wafer is covered on the top as the top wafer, and the two silicon wafers are sealed and bonded using high-temperature-resistant glue or bonded together through a bonding process. The thickness of the temperature measurement device 11 after bonding is 1 mm to 2 mm. It should be noted that the processes for processing grooves or blind holes on the silicon wafer in the two structures include, but are not limited to, dry etching, wet etching, laser etching, focused ion beam etching, reactive ion beam etching, electrochemical etching, atomic layer etching, ultrasonic-assisted processing, electron beam etching, and nanoimprint combined etching. The actual selection can comprehensively consider factors such as the material properties of the silicon wafer, structural accuracy, production cost, and production efficiency. The bonding of the two silicon wafers can adopt direct bonding or a non-high-temperature bonding process, that is, adhesive bonding, with the process temperature below 300°C. The types of glue used include, but are not limited to, epoxy resin, benzocyclobutene, polyimide, and photoresist.

[0031] Based on the foregoing embodiments, the embodiments of the present application provide a wireless wafer temperature measurement method, which can be used for Figures 1 to 12 the wireless wafer temperature measurement system 1 corresponding to the embodiment. Please refer toFigure 13 , which is a schematic flowchart of a wireless wafer temperature measurement method provided by an embodiment of the present application. The wireless wafer temperature measurement method specifically includes the following steps: S101: Sequentially transmit excitation signals with different frequencies to each surface acoustic wave sensor.

[0032] Exemplarily, assuming that 10 sensors are used for temperature measurement simultaneously in the embodiment of the present application, the frequencies of the excitation signals can be 2.4 GHz, 2.41 GHz, 2.42 GHz, 2.43 GHz, 2.44 GHz, 2.45 GHz, 2.46 GHz, 2.47 GHz, 2.48 GHz, and 2.49 GHz respectively.

[0033] S102: Sequentially receive the echo signals of each surface acoustic wave sensor, and determine the temperature at the corresponding position of each surface acoustic wave sensor according to the frequency difference between the echo signal and the excitation signal and the mapping relationship between the preset frequency difference and the temperature.

[0034] Exemplarily, in the embodiment of the present application, the mapping relationship includes but is not limited to function curves and two-dimensional tables, etc., which can be obtained through experimental data, and the distribution positions of each surface acoustic wave sensor 1121 have been calibrated at the factory and cover the entire wafer surface area.

[0035] S103: Generate a temperature field image based on the temperature at the corresponding position of each surface acoustic wave sensor, and display the temperature field image.

[0036] Exemplarily, in the embodiment of the present application, the temperature at the corresponding position of each surface acoustic wave sensor 1121 can be smoothed and continuous through an interpolation algorithm to reconstruct the two-dimensional temperature field of the entire wafer surface area, and a two-dimensional color thermal map can be displayed.

[0037] It should be noted that the descriptions of the same steps and the same content in this embodiment and other embodiments can refer to the descriptions in other embodiments, and will not be repeated here.

[0038] The wireless wafer temperature measurement system and method provided by the embodiments of the present application use the second antenna and the first antenna to sequentially transmit excitation signals with different frequencies to each surface acoustic wave sensor in the surface acoustic wave sensor array to cause each surface acoustic wave sensor to work sequentially. Since the surface acoustic wave sensor has a piezoelectric effect, when the temperature changes, the elastic constant and density of the piezoelectric material change accordingly, and the propagation speed of the surface acoustic wave in the sensor changes, which will cause a frequency shift. Thus, the first antenna and the second antenna can be used to sequentially receive the echo signals of each surface acoustic wave sensor, and based on the frequency difference between the echo signal and the excitation signal and the mapping relationship between the preset frequency difference and the temperature, the temperature at the corresponding position of each surface acoustic wave sensor can be quickly determined. It does not require battery power supply and is not limited by the battery capacity, and can continuously and real-time measure the temperature. Furthermore, after generating a temperature field image based on the temperature at the corresponding position of each surface acoustic wave sensor, it can be intuitively displayed at a glance, greatly improving the production efficiency of semiconductor manufacturing.

[0039] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, 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, it should be considered that the scope described in this specification.

[0040] Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A wireless wafer temperature measurement system, characterized in that, The wireless wafer temperature measurement system includes: A temperature measurement device, which includes two wafers, a surface acoustic wave sensor array disposed between the two wafers, and a first antenna connected to the surface acoustic wave sensor array. The excitation signal frequencies of the surface acoustic wave sensors in the surface acoustic wave sensor array are different. A signal control and processing device, which includes a second antenna, an output unit, a radio frequency signal generator and a signal demodulator connected to the second antenna. The output unit is connected to the signal demodulator. The radio frequency signal generator is used to sequentially transmit different frequency excitation signals to each surface acoustic wave sensor through the second antenna and the first antenna. The signal demodulator is used to sequentially receive the echo signals of each surface acoustic wave sensor through the first antenna and the second antenna, and determine the temperature at the corresponding position of each surface acoustic wave sensor according to the frequency difference between the echo signal and the excitation signal and the mapping relationship between the preset frequency difference and the temperature. The output unit is used to generate a temperature field image according to the temperature at the corresponding position of each surface acoustic wave sensor and display the temperature field image.

2. The wireless wafer temperature measurement system according to claim 1, wherein The surface acoustic wave sensor includes a piezoelectric substrate, and a first reflection grating, an interdigital transducer and a second reflection grating arranged in sequence on the piezoelectric substrate. The interdigital periods of the interdigital transducers in the surface acoustic wave sensors are different.

3. The wireless wafer temperature measurement system according to claim 2, wherein The piezoelectric substrate includes a lithium niobate substrate, an aluminum nitride substrate and a lithium tantalate substrate.

4. The wireless wafer temperature measurement system according to claim 2, wherein, The interdigital transducer includes a first interdigital electrode and a second interdigital electrode arranged alternately with each other, and each interdigital electrode is provided with a bus bar.

5. The wireless wafer temperature measurement system according to claim 4, wherein, The interdigital width of the interdigital transducer is equal to the interdigital pitch, and both are 1 / 4 of the interdigital period.

6. The wireless wafer temperature measurement system according to claim 5, wherein The aperture width range of the interdigital transducer is 100 times to 1000 times the interdigital period.

7. The wireless wafer temperature measurement system according to any one of claims 1 to 6, characterized in that, The first antenna is a rectangular microstrip antenna. The patch length of the rectangular microstrip antenna is 32 mm, the patch width is 22 mm, and the feeding method is 50Ω microstrip line feeding, and the feeder width is 2.5 mm.

8. The wireless wafer temperature measurement system according to claim 7, characterized in that The second antenna is a horn antenna. The waveguide length in the horn antenna is 156.25 mm, the waveguide width is 62.5 mm, the waveguide height is 31.25 mm, and the horn mouth length is 300 mm, the horn mouth width is 250 mm, and the horn mouth height is 125 mm.

9. The wireless wafer temperature measurement system according to claim 8, wherein, The working main frequencies of the first antenna and the second antenna are both 2.4 GHz, and the bandwidth is ±0.5 GHz.

10. A wireless wafer temperature measurement method, characterized in that, The wireless wafer temperature measurement method is used for the wireless wafer temperature measurement system according to any one of claims 1 to 9. The wireless wafer temperature measurement method includes: Sequentially transmitting different frequency excitation signals to each surface acoustic wave sensor. Sequentially receiving the echo signals of each surface acoustic wave sensor, and determining the temperature at the corresponding position of each surface acoustic wave sensor according to the frequency difference between the echo signal and the excitation signal and the mapping relationship between the preset frequency difference and the temperature. Generating a temperature field image according to the temperature at the corresponding position of each surface acoustic wave sensor and displaying the temperature field image.

Images