A wireless wafer temperature measurement system and a temperature measurement method

Abstract

The application discloses a wireless wafer temperature measuring system and a temperature measuring method, and relates to the technical field of semiconductor manufacturing. The wireless wafer temperature measuring system comprises a temperature measuring device and a signal control and processing device. The temperature measuring device comprises two wafers, an array of surface acoustic wave sensors and a first antenna. 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 sequentially transmitting excitation signals with different frequencies to each surface acoustic wave sensor through the antenna. The signal demodulator is used for sequentially receiving echo signals of each surface acoustic wave sensor through the antenna, and determining the temperature of the position corresponding to each surface acoustic wave sensor according to the frequency difference between the echo signals and the excitation signals and the mapping relationship between the preset frequency difference and the temperature. The output unit is used for generating a temperature field image according to the temperature of the position corresponding to each surface acoustic wave sensor and displaying the temperature field image. The system can continuously and real-timely measure the temperature, and greatly improves the production efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, in particular to a wireless wafer temperature measurement system and a temperature measurement method. BACKGROUND

[0002] In the manufacturing process of semiconductor chips, it is increasingly important to accurately monitor the temperature of wafers, which can help process engineers to adjust etching conditions, verify and match cavities, and ensure process stability and improve product yield.

[0003] At present, the related technology mainly adopts wireless wafer temperature measurement, that is, after data reading, the temperature value is obtained by sending the data to an external receiving device through wireless communication technology for processing. The temperature sensing elements of this method include thin film thermistors and integrated circuit type temperature sensors, etc. However, the sensor end needs to be powered by a battery, and due to the limited battery capacity, it cannot work continuously for a long time, which directly affects the production efficiency of semiconductor manufacturing. Moreover, after the temperature measurement is completed, the data can be read by a reader, and the real-time temperature measurement is poor. SUMMARY

[0004] In view of the above defects or shortcomings in the related art, it is desirable 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, the present application provides a wireless wafer temperature measurement system, which comprises:

[0006] a temperature measurement device, the temperature measurement device comprising two wafers, a surface acoustic wave sensor array arranged between the two wafers, and a first antenna connected to the surface acoustic wave sensor array, the excitation signal frequencies of each surface acoustic wave sensor in the surface acoustic wave sensor array being different;

[0007] a signal control and processing device, the signal control and processing device comprising a second antenna, an output unit, a radio frequency signal generator and a signal demodulator connected to the second antenna, the output unit being connected to the signal demodulator; the radio frequency signal generator is used to emit excitation signals of different frequencies to each surface acoustic wave sensor in time sequence through the second antenna and the first antenna; the signal demodulator is used to receive echo signals of each surface acoustic wave sensor in time sequence through the first antenna and the second antenna, and determine the temperature of the corresponding position of each surface acoustic wave sensor according to the frequency difference between the echo signals and the excitation signals 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 of the corresponding position of each surface acoustic wave sensor and display the temperature field image.

[0008] Optionally, the surface acoustic wave sensor in some embodiments of the present application comprises a piezoelectric substrate, and a first reflective grating, an interdigital transducer and a second reflective grating arranged in sequence on the piezoelectric substrate, and the interdigital transducer in each surface acoustic wave sensor has different interdigital period.

[0009] Optionally, the piezoelectric substrate in some embodiments of the present application comprises a lithium niobate substrate, an aluminum nitride substrate and a lithium tantalate substrate.

[0010] Optionally, the interdigital transducer in some embodiments of the present application comprises first interdigital electrodes and second interdigital electrodes arranged in interlaced manner, and each interdigital electrode is provided with a bus bar.

[0011] Optionally, the interdigital transducer in some embodiments of the present application has an interdigital width equal to an interdigital spacing, and both are 1 / 4 of the interdigital period.

[0012] Optionally, the interdigital transducer in some embodiments of the present application has an aperture width ranging from 100 times to 1000 times of the interdigital period.

[0013] Optionally, the first antenna in some embodiments of the present application is a rectangular microstrip antenna, the patch length of the rectangular microstrip antenna is 32 mm, the patch width is 22 mm, and the feed mode is 50Ω microstrip line feed with a feed line width of 2.5 mm.

[0014] Optionally, the second antenna in some embodiments of the present application is a horn antenna, the waveguide length of 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.

[0015] Optionally, the first antenna and the second antenna in some embodiments of the present application both have a working main frequency of 2.4 GHz and a bandwidth of ±0.5 GHz.

[0016] In a second aspect, the present application provides a wireless wafer temperature measurement method, which is used in the wireless wafer temperature measurement system of any one of the first aspect, and the wireless wafer temperature measurement method comprises:

[0017] sequentially transmitting excitation signals with different frequencies to each surface acoustic wave sensor;

[0018] sequentially receiving echo signals of each surface acoustic wave sensor, and determining the temperature of the corresponding position of each surface acoustic wave sensor according to the frequency difference between the echo signals and the excitation signals and the mapping relationship between the preset frequency difference and the temperature;

[0019] 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.

[0020] As can be seen from the above technical solutions, the embodiments of this application have the following advantages:

[0021] This application provides a wireless wafer temperature measurement system and method. The system uses a second antenna and a first antenna to sequentially transmit excitation signals of different frequencies to each surface acoustic wave (SAW) sensor in an array, causing the SAW sensors to operate sequentially. Because SAW sensors exhibit piezoelectric effects, the elastic constant and density of the piezoelectric material change with temperature variations, causing a change in the propagation speed of SAW waves within the sensors. This results in a frequency shift. The system then uses the first and second antennas to sequentially receive the echo signals from each SAW sensor. Based on the frequency difference between the echo signal and the excitation signal, and the mapping relationship between the preset frequency difference and temperature, the system quickly determines the temperature at the corresponding location of each SAW sensor. This system requires no battery power, is not limited by battery capacity, and can continuously and in real-time measure temperature. Furthermore, it generates a temperature field image based on the temperature at the corresponding location of each SAW sensor and displays it intuitively, providing a clear overview and significantly improving the production efficiency of semiconductor manufacturing. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A structural block diagram of a wireless wafer temperature measurement system provided in an embodiment of this application;

[0024] Figure 2 A timing control diagram provided for an embodiment of this application;

[0025] Figure 3 A top view of a surface acoustic wave sensor provided in an embodiment of this application;

[0026] Figure 4 An embodiment provided in this application Figure 3 The front view of the surface acoustic wave sensor is shown.

[0027] Figure 5 This is a schematic diagram of the structure of an interdigital transducer provided in an embodiment of this application;

[0028] Figure 6 This is a schematic diagram of the structure of a first antenna provided in an embodiment of this application;

[0029] Figure 7A structure schematic diagram of a second antenna provided by an embodiment of the present application;

[0030] Figure 8 A structure schematic diagram of a second antenna provided by an embodiment of the present application Figure 7 A left view of the second antenna shown in the figure;

[0031] Figure 9 A structure schematic diagram of a second antenna provided by an embodiment of the present application Figure 7 A top view of the second antenna shown in the figure;

[0032] Figure 10 A structure schematic diagram of a second antenna provided by an embodiment of the present application Figure 7 A front view of the second antenna shown in the figure;

[0033] Figure 11 A manufacturing process schematic diagram of a three-layer structure temperature measuring device provided by an embodiment of the present application;

[0034] Figure 12 A manufacturing process schematic diagram of a double-layer structure temperature measuring device provided by an embodiment of the present application;

[0035] Figure 13 A flowchart of a wireless wafer temperature measuring method provided by an embodiment of the present application.

[0036] Reference signs:

[0037] 1-wireless wafer temperature measuring system, 11-temperature measuring device, 111-wafer, 112-surface acoustic wave sensor array, 1121-surface acoustic wave sensor, a-piezoelectric substrate, b-first reflective grating, c-interdigital transducer, c1-first interdigital electrode, c2-second interdigital electrode, c3-bus bar, c4-interdigital width, c5-interdigital spacing, c6-aperture width, d-second reflective grating, P-interdigital period, 113-first antenna, e1-patch length, e2-patch width, e3-feed line width, 12-signal control and processing device, 121-second antenna, g1-waveguide length, g2-waveguide width, g3-waveguide height, g4-horn length, g5-horn width, g6-horn height, 122-output unit, 123-radio frequency signal generator, 124-signal demodulator. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0039] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The following examples illustrate this. Figures 1 to 13 The wireless wafer temperature measurement system and method provided in the embodiments of this application are described in detail.

[0041] Please refer to Figure 1 This is a structural block diagram of a wireless wafer temperature measurement system provided in an embodiment of this 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 (SAW) sensor array 112 disposed between the two wafers 111, and a first antenna 113 connected to the SAW sensor array 112. The excitation signal frequencies of each SAW sensor 1121 in the SAW 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, and a radio frequency signal generator 123 and a signal demodulator 124 connected to the second antenna 121. The output unit 122 is connected to the signal demodulator 124.

[0042] During actual temperature measurement, the radio frequency signal generator 123 can transmit excitation signals of different frequencies to each surface acoustic wave sensor 1121 in a timely manner through the second antenna 121 and the first antenna 113. The signal demodulator 124 can receive the echo signals from each surface acoustic wave sensor 1121 in a timely manner through the first antenna 113 and the second antenna 121, i.e. Figure 2 The time-division multiplexing control method shown places the signal transmission and reception of each surface acoustic wave sensor 1121 in different time periods, effectively avoiding signal interference. For example, the transmission period T 发 ≤10ms, reception period T 收 ≤10ms. Furthermore, the signal demodulator 124 can also quickly determine the temperature of each surface acoustic wave sensor 1121 at its corresponding location based on the frequency difference between the echo signal and the excitation signal and the preset mapping relationship between the frequency difference and temperature. It should be noted that the mapping relationship includes, but is not limited to, function curves and two-dimensional tables, 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 based on the temperature of each surface acoustic wave sensor 1121 at its corresponding location and display the temperature field image intuitively. For example, by using an interpolation algorithm to smooth and continuous the image, a two-dimensional temperature field of the entire wafer surface area can be reconstructed and a two-dimensional color thermal image can be displayed.

[0043] In some embodiments of this application, such asFigures 3 to 5 As shown, the surface acoustic wave sensor 1121 comprises a piezoelectric substrate a and a first reflective grating b, an interdigital transducer c and a second reflective grating d arranged in sequence on the piezoelectric substrate a. The interdigital transducer c can realize the conversion between electromagnetic wave and surface acoustic wave. The first reflective grating b and the second reflective grating d can reflect the surface acoustic wave and form a resonance between the two reflective gratings. 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 a periodic elastic deformation, so that the input radio signal is converted 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 two reflective gratings, it is reflected by the reflective gratings and returns to the interdigital transducer c again, and is superimposed and enhanced in the reflective gratings to form a resonance. Then, due to the existence of the positive piezoelectric effect, the resonated acoustic signal generates a periodic alternating electric field between the interdigital transducer c, and the surface acoustic wave is converted into an electrical signal output again, completing the conversion between the electrical signal, the acoustic signal and the electrical signal, and the conversion between the electrical energy, the mechanical energy and the electrical energy. Finally, the converted electrical signal is responded by the first antenna 113 to realize the wireless sensing function.

[0044] Further, the piezoelectric substrate a includes but is not limited to a lithium niobate (LiNbO3) substrate, an aluminum nitride (AlN) substrate and a lithium tantalate (LiTaO3) substrate, etc. For example, Figure 5 As shown, the interdigital transducer c includes but is not limited to a first interdigital electrode c1 and a second interdigital electrode c2 arranged in an interlaced manner, etc. 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 0of the interdigital transducer c, that is:

[0045] f 0= v / P (1)

[0046] In formula (1), v0represents the wave speed of the surface acoustic wave, which is related to the elastic constant and the density of the piezoelectric substrate material. For lithium niobate material, the wave speed v0is in the range of 3000 m / s to 4000 m / s. Due to the anisotropy of lithium niobate material, the specific wave speed value is related to the propagation direction in the crystal. The propagation direction is determined, and the specific wave speed value is determined. As can be seen from formula (1), the characteristic frequency f0of the interdigital transducer c is inversely proportional to the interdigital period P. In the embodiment 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 of a corresponding frequency. v v v0= 3000-4000 m / s f

[0047] ​​The aperture width c6 is related to the frequency offset; the larger the aperture width c6, the smaller the frequency offset. In this embodiment, the aperture width c6 of the interdigital transducer c can range from 100 times to 1000 times the interdigital period P, which is a suitable range. Interdigital transducers c with different interdigital periods are designed for each surface acoustic wave sensor 1121, such as P1, P2, ..., P... n etc., so that they correspond to different characteristic frequencies, for example f 1. f 2, ... f n Within a certain range, the frequency shift (Δ) of the surface acoustic wave sensor 1121... f ) and temperature change (Δ T The relationship between temperature change and frequency shift is monotonically linear, meaning the temperature change and frequency shift can be expressed as:

[0048] Δ f = f 0· α ·Δ T (2)

[0049] In equation (2), α This represents the temperature coefficient, which is related to the material properties. For lithium niobate materials, the temperature coefficient is... α The temperature coefficient of aluminum nitride material is -75 ppm / °C. α The temperature coefficient of lithium tantalate material is -25 ppm / °C. α With a temperature coefficient of -30 ppm / °C, lithium niobate material exhibits a relatively large absolute value, resulting in a significant frequency shift due to temperature changes. This makes it suitable for high-precision temperature measurement, with a theoretical sensitivity of ±0.1°C, meeting the accuracy requirements for wafer temperature measurement. Furthermore, lithium niobate material can operate at temperatures exceeding 1000°C. The interdigitated electrodes are fabricated on the lithium niobate substrate using a deposition photolithography process, giving the surface acoustic wave sensor 1121 high-temperature resistance.

[0050] During wafer temperature measurement, the surface acoustic wave sensor 1121 operates in the GHz band, and the size of the interdigital period P is... The frequency offset of the interdigital transducer c is designed to have a sufficient margin, reaching the order of MHz, to ensure that the temperature measurement range can reach more than 500 DEG C. For example, the thickness of a single lithium niobate substrate material is less than or equal to 1 mm, and the length x width is less than or equal to 10 mm x 5 mm. For another example, the frequency interval of each surface acoustic wave sensor 1121 is set to 10 MHz, and assuming that 10 sensors are used to measure the temperature at the same time, the characteristic frequencies of these sensors are 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. The interdigital transducer c is made by electron beam lithography technology. For the above-mentioned sensors with characteristic frequencies of 2.4 GHz to 2.49 GHz, 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 . At present, the wafer temperature measurement range for silicon-based semiconductor applications is less than or equal to 200 DEG C, and for new semiconductors such as silicon carbide, higher temperature measurement ranges are required. Therefore, the temperature measurement range of the surface acoustic wave sensor 1121 in the embodiment of the present application is more than 500 DEG C, which can greatly expand the application range.

[0051] In some embodiments of the present application, as shown in Figure 6 , the first antenna 113 can be a rectangular microstrip antenna, the patch length e1 of which is 32 mm, the patch width e2 is 22 mm, and the feed mode is 50 Ω microstrip line feed, and the feed line width e3 is 2.5 mm. 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 one rectangular microstrip antenna, or the number of rectangular microstrip antennas can also be one, that is, each surface acoustic wave sensor 1121 shares one rectangular microstrip antenna, and through time division multiplexing, the mutual interference between signals is avoided. The working main frequency of the rectangular microstrip antenna is 2.4 GHz, and the bandwidth is ±0.5 GHz. Further, as shown in Figures 7 to 10As shown, the second antenna 121 can be a horn antenna, in which 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. Such a configuration has the advantages of good directivity and improved signal transmission quality. The working main frequency of the horn antenna is 2.4 GHz, and the bandwidth is ±0.5 GHz.

[0052] In some embodiments of the present application, the structure of the temperature measuring device 11 includes, but is not limited to, the following double-layer structure and three-layer structure, etc., which have excellent repeatability and consistency, are convenient for mass production, and are low in cost. For example Figure 11 As shown in the three-layer structure, during manufacturing, a silicon wafer is first used as a bottom wafer, and a groove or a blind hole is processed on the bottom wafer, which has the same shape and depth as 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, the gap is filled with glue for sealing the circuit, and finally a silicon wafer is covered as a top wafer. The two silicon wafers are sealed and bonded together using high-temperature-resistant glue or through a bonding process. The thickness of the bonded temperature measuring device 11 is 1 mm to 2 mm. The outer dimensions of the bottom wafer and the top wafer in the temperature measuring 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, and 12 inches, etc.

[0053] For another example Figure 12 As shown in the double-layer structure, during manufacturing, a silicon wafer is first used as a bottom wafer, and then the integrated surface acoustic wave sensor array 112 is directly integrated on the bottom wafer through a micro-electro-mechanical system processing technology, that is, there is no thin film layer. Finally, a silicon wafer is covered as a top wafer, and the two silicon wafers are sealed and bonded together using high-temperature-resistant glue or through a bonding process. The thickness of the bonded temperature measuring device 11 is 1 mm to 2 mm. It should be noted that the process of processing a groove or a blind hole on a silicon wafer includes, but is not limited to, dry etching, wet etching, laser etching, focused ion beam etching, reactive ion beam etching, electrochemical etching, atomic layer etching, ultrasonic auxiliary processing, electron beam etching, and nano-imprint combined etching, etc. The actual selection can consider factors such as the material properties of the silicon wafer, the structural precision, the production cost, and the production efficiency, etc. The bonding of the two silicon wafers can adopt direct bonding or non-high-temperature bonding process, that is, adhesive bonding, with a process temperature below 300°C. The types of glue used include, but are not limited to, epoxy resin, benzocyclobutene, polyimide, and photoresist, etc.

[0054] Based on the foregoing embodiments, the present application provides a wireless wafer temperature measuring method, which can be used for Figures 1 to 12 The wireless wafer temperature measuring system 1 corresponding to the embodiments. Please refer toFigure 13 Fig. 1 is a flowchart of a wireless wafer temperature measurement method according to an embodiment of the present application, which specifically includes the following steps:

[0055] S101, sequentially transmitting excitation signals with different frequencies to each SAW sensor.

[0056] For example, assuming that 10 sensors are used to measure temperature 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.

[0057] S102, sequentially receiving echo signals of each SAW sensor, and determining the temperature of the corresponding position of each SAW 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.

[0058] For example, the mapping relationship in the embodiment of the present application includes but is not limited to a function curve and a two-dimensional table, which can be obtained through experimental data, and the distribution positions of each SAW sensor 1121 are calibrated when leaving the factory, covering the entire wafer surface area.

[0059] S103, generating a temperature field image according to the temperature of the corresponding position of each SAW sensor and displaying the temperature field image.

[0060] For example, the embodiment of the present application can smooth and continuously the temperature of the corresponding position of each SAW sensor 1121 through an interpolation algorithm, reconstruct a two-dimensional temperature field of the entire wafer surface area, and display a two-dimensional color heat map.

[0061] It should be noted that the same steps and the same content in the present embodiment and other embodiments are described with reference to the description of other embodiments, which will not be repeated here.

[0062] The wireless wafer temperature measurement system and the temperature measurement method provided by the embodiments of the present application can cause each surface acoustic wave sensor in the surface acoustic wave sensor array to work in turn by the second antenna and the first antenna transmitting excitation signals with different frequencies to each surface acoustic wave sensor in time sequence. Since the surface acoustic wave sensor has piezoelectric effect, the elastic constant and the density of the piezoelectric material change with the change of temperature, the propagation speed of the surface acoustic wave in the sensor changes, which will cause frequency shift. Thus, the first antenna and the second antenna can receive echo signals of each surface acoustic wave sensor in time sequence, and based on the frequency difference between the echo signals and the excitation signals and the mapping relationship between the preset frequency difference and the temperature, the temperature of the position corresponding to each surface acoustic wave sensor can be quickly determined. The temperature measurement does not need battery power supply, is not limited by the battery capacity, can continuously and real-timely measure the temperature, and then intuitively display the temperature field image based on the temperature of the position corresponding to each surface acoustic wave sensor, which is easy to understand, and greatly improves the production efficiency of semiconductor manufacturing.

[0063] The technical features of the above embodiments can be combined arbitrarily, and to make the description concise, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0064] The principles and implementation modes of the present application are described by using specific examples in the present application, and the above embodiment descriptions are only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation modes and application ranges will be changed. In conclusion, the content of the present application should not be understood as the limitation of the present application.

Claims

1. A wireless wafer temperature measurement system, characterized in that, The wireless wafer temperature measurement system includes: A temperature measuring device includes two wafers, a surface acoustic wave (SAW) sensor array disposed between the two wafers, and a first antenna connected to the SAW sensor array. The bottom and top wafers of the two wafers have the same external dimensions as the semiconductor wafer to be processed. The bottom wafer has grooves or blind vias with shapes and depths consistent with the SAW sensor array. The bottom and top wafers are bonded together using a bonding process, resulting in a temperature measuring device with a thickness of 1mm to 2mm. The excitation signal frequencies of the SAW sensors in the SAW sensor array are different, and the interdigital transducers have different interdigital periods. The SAW sensors operate in the GHz band with a frequency spacing of 10MHz, and the interdigital period is [missing information]. The frequency offset of the interdigital transducer is on the order of MHz; the surface acoustic wave sensor includes a piezoelectric substrate and a first reflective grating, an interdigital transducer and a second reflective grating arranged sequentially on the piezoelectric substrate, wherein the piezoelectric substrate is a lithium niobate substrate. A signal control and processing device includes a second antenna, an output unit, and 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 transmit excitation signals of different frequencies to each surface acoustic wave sensor in a time sequence through the second antenna and the first antenna, with a transmission period ≤10ms. The signal demodulator is used to receive echo signals from each surface acoustic wave sensor in a time sequence through the first antenna and the second antenna, with a reception period ≤10ms. The transmission and reception periods of each surface acoustic wave sensor are adjacent, and the temperature at the corresponding location of each surface acoustic wave sensor is determined based on the frequency difference between the echo signal and the excitation signal and a preset mapping relationship between the frequency difference and temperature. The output unit is used to generate a temperature field image based on the temperature at the corresponding location of each surface acoustic wave sensor and to display the temperature field image. The first antenna is a rectangular microstrip antenna with a patch length of 32mm, a patch width of 22mm, and a 50Ω microstrip line feed with a feed line width of 2.5mm. The second antenna is a horn antenna with a waveguide length of 156.25mm, a waveguide width of 62.5mm, a waveguide height of 31.25mm, a horn aperture length of 300mm, a horn aperture width of 250mm, and a horn aperture height of 125mm. Both the first and second antennas operate at a main frequency of 2.4GHz with a bandwidth of ±0.5GHz.

2. The wireless wafer temperature measurement system according to claim 1, characterized in that, The interdigital transducer includes a first interdigital electrode and a second interdigital electrode arranged in an alternating manner, and each interdigital electrode is provided with a busbar.

3. The wireless wafer temperature measurement system according to claim 2, characterized in that, The width of the interdigital transducer is equal to the distance between the interdigital fingers, and both are 1 / 4 of the interdigital period.

4. The wireless wafer temperature measurement system according to claim 3, characterized in that, The aperture width of the interdigital transducer ranges from 100 to 1000 times the interdigital period.

5. A wireless wafer temperature measurement method, characterized in that, The wireless wafer temperature measurement method is used in the wireless wafer temperature measurement system according to any one of claims 1 to 4, and the wireless wafer temperature measurement method includes: Excitation signals of different frequencies are transmitted to each surface acoustic wave sensor in a sequential manner, with a transmission period of ≤10ms; The echo signals of each surface acoustic wave sensor are received in sequence, with a receiving period of ≤10ms. The transmission period and receiving period of each surface acoustic wave sensor are adjacent. The temperature of each surface acoustic wave sensor at its corresponding position is determined according to the frequency difference between the echo signal and the excitation signal and the mapping relationship between the preset frequency difference and temperature. A temperature field image is generated based on the temperature at the corresponding location of each surface acoustic wave sensor, and the temperature field image is displayed.

Images