Wide-temperature-zone intelligent temperature sensor design and preparation method thereof

Abstract

The invention provides a wide-temperature-range intelligent temperature sensor design and a preparation method thereof, the wide-temperature-range intelligent temperature sensor design comprises an insulating substrate, a thin film temperature sensing unit, a thin film constant value reference resistor unit and a metal electrode layer, the thin film temperature sensing unit and the thin film constant value reference resistor unit form a layout above the insulating substrate through an MEMS technology, signal transmission is realized through the metal electrode layer; wherein the thin film temperature sensing unit comprises a temperature sensitive thin film, the thin film constant value reference resistor unit comprises a constant value resistor thin film, the temperature sensitive thin film is prepared above the insulating substrate, and the constant value resistor thin film is prepared above the insulating substrate. And the temperature sensitive film is connected with the constant resistance film through the metal electrode layer. The integration of the thin film temperature sensor unit and the thin film constant value reference resistor unit on the monolithic substrate is realized, the device size is obviously reduced, and the response speed is improved.

Description

Technical Field

[0001] This application relates to the field of temperature sensors and thin-film resistor fabrication, specifically to the design and fabrication method of a wide-temperature-range intelligent temperature sensor. Background Technology

[0002] High-precision temperature sensing and control technologies are crucial in aerospace, defense, medical treatment, biomedicine, and everyday life. Traditional temperature measurement systems are bulky, power-hungry, and inconvenient to use, especially in aerospace and electronics applications that demand high precision and miniaturization. The large size and weight of these devices cause significant inconvenience, and the inability to process temperature signals in a timely manner leads to distortion during transmission. Dedicated temperature sensing integrated circuit chips, on the other hand, are small, have a fast response time, avoid distortion, and efficiently implement complex functions such as signal conditioning, high-precision analog-to-digital conversion, digital interfaces, and control logic.

[0003] However, to construct a complete, intelligent, and easily applicable high-precision miniaturized temperature measurement microsystem, the integration and unification of application-specific integrated circuits (ASICs) and temperature sensors still need to be addressed. Currently used discrete temperature sensors and volume constant resistors suffer from drawbacks such as low integration density, slow response speed, delay introduced by external wires, and noise, making it difficult to achieve optimal collaborative operation and efficient cascading with advanced application-specific integrated circuit (ASIC) chips.

[0004] A search of existing technologies revealed the following:

[0005] Chinese invention patent 201910260398.5 proposes a negative temperature coefficient resistive cryogenic temperature sensor and its fabrication method based on the design concept of resistive thin-film temperature sensors. The temperature sensor is small in size, high in accuracy, and compatible with micro / nano fabrication and MEMS processing technologies. Although it achieves a high degree of miniaturization, as a discrete temperature sensor integrating only on-chip electrodes, it must rely on external wires for electrical connection and signal transmission with other devices or circuit chips.

[0006] Guanqun Feng, Zhengcan Pan, Can Wang, and others published a paper titled "Achieving high sheet resistance and near-zero temperature coefficient of resistance in NiCr film resistors by Al interlayers" in the Journal of Alloys and Compounds. This paper designs and fabricates a constant-value thin-film resistor with a wide resistance range, high stability, and extremely low temperature coefficient of resistance, providing material and process solutions for high-performance embedded resistors and semiconductor integration applications. However, on the one hand, this research does not involve co-integration design with temperature sensors, and cannot directly form the core of an integrated temperature sensing microsystem with an embedded constant-value reference resistor. On the other hand, the multi-layer design and annealing treatment used in this paper to adjust the temperature coefficient of resistance, while achieving high sheet resistance and extremely low temperature coefficient of resistance, are complex to manufacture and incompatible with the fabrication process of thin-film temperature sensors. Temperature sensors sensitive to composition and structure are easily affected and may fail.

[0007] In summary, most existing technologies and research typically focus on improving the key performance indicators of discrete temperature sensors and resistors, lacking a system-level design approach. This results in significant limitations in integration with other functional devices, especially application-specific integrated circuits (ASICs), signal transmission, and functional coordination. Intelligent temperature sensors that highly integrate thin-film temperature sensing units and thin-film constant-value reference resistor units on a monolithic substrate are key to realizing truly miniaturized, high-precision, and integrated temperature measurement microsystems, and represent an urgent need to drive the development of cutting-edge temperature measurement technologies. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this application provides a design and fabrication method for a wide-temperature-range intelligent temperature sensor.

[0009] A first aspect of this application provides a wide-temperature-range intelligent temperature sensor, comprising: an insulating substrate, a thin-film temperature sensing unit, a thin-film constant reference resistor unit, and a metal electrode layer. The thin-film temperature sensing unit and the thin-film constant reference resistor unit are arranged on the insulating substrate using MEMS technology, and signal transmission is achieved through the metal electrode layer.

[0010] The thin-film temperature sensing unit includes a temperature-sensitive thin film, and the thin-film constant value reference resistor unit includes a constant value resistor thin film. The temperature-sensitive thin film is fabricated on the insulating substrate, and the constant value resistor thin film is fabricated on the insulating substrate. The temperature-sensitive thin film is connected to the constant value resistor thin film through the metal electrode layer.

[0011] Optionally, the wide-temperature-range intelligent temperature sensor is an integrated temperature sensor chip that integrates a thin-film temperature sensing unit and a thin-film constant reference resistor unit on a monolithic insulating substrate.

[0012] Optionally, in a monolithically integrated temperature sensor chip, the thin-film temperature sensing unit and the constant-value reference resistor unit are integrated to reduce signal delay and noise caused by external wires; the metal electrode layout and electrical interface characteristics of the metal electrode layer enable cascading with a dedicated temperature measurement ASIC chip to construct a closed-loop temperature control system.

[0013] Optionally, the wide temperature range refers to a temperature range of 4.2K-300K.

[0014] A second aspect of this application provides a method for fabricating a wide-temperature-range intelligent temperature sensor, comprising:

[0015] S1. Select an insulating substrate and perform cleaning and drying processes;

[0016] S2. A temperature-sensitive thin film is prepared on the insulating substrate using a sensitive thin film preparation process;

[0017] S3. First photolithography: A photolithographic pattern is formed on the temperature-sensitive thin film, and the pattern is etched by an ion beam etching process to obtain the thin film temperature sensing unit;

[0018] S4. After cleaning the photoresist, perform a second photolithography process to pattern the photoresist on the surface of the obtained temperature-sensitive thin film pattern. This serves as a protective layer to prevent the properties of the temperature-sensitive film pattern from being damaged by subsequent processes. The polarity of the photoresist used in this step must be different from that used in the next photolithography process to ensure that the photoresist protective layer in this step will not be removed in the next photolithography step.

[0019] S5. A constant resistance thin film is prepared on the insulating substrate using a thin film preparation process;

[0020] S6. Third photolithography: a photolithographic pattern is formed on the constant value resistor film, and the pattern is etched by ion beam etching process to obtain the thin film constant value reference resistor unit;

[0021] S7. After cleaning the photoresist, a fourth photolithography is performed to form photolithographic patterns on the insulating substrate, the thin film temperature sensing unit, and the thin film constant value reference resistor unit. Then, a metal electrode layer is prepared at the electrode pattern using a lift-off process or an etching process.

[0022] In step S4, an insulating and etch-resistant protective layer is used instead of a photoresist protective layer.

[0023] When using an insulating, etch-resistant protective layer, after steps S1-S3, the process includes:

[0024] S4. An etching-resistant protective layer is formed on the surface of the obtained temperature-sensitive thin film pattern using a deposition process;

[0025] S4.1: The etching-resistant material protective layer formed by the deposition process is patterned by photolithography. Photoresist is patterned on the surface of the insulating etching-resistant material, and the pattern is etched by plasma etching or dielectric etching process to obtain the etching-resistant material protective layer, so as to protect the properties of the temperature-sensitive film pattern from being damaged by subsequent processes.

[0026] Step S4.1 is followed by steps S5-S7.

[0027] Optionally, the temperature-sensitive film is made of transition metal nitrides and oxynitrides prepared from transition metal elements, as well as thermosensitive metal oxides and platinum metal materials.

[0028] The transition metal element includes any one of titanium, zirconium, hafnium, vanadium, niobium, tantalum, or chromium; the thickness of the temperature-sensitive film is 10 nm to 500 nm.

[0029] Optionally, the sensitive thin film preparation process includes any one of chemical vapor deposition, pulsed laser deposition, electron beam evaporation, reactive magnetron sputtering, and thick film printing.

[0030] Optionally, the protective layer is a photoresist mask layer or a deposited insulating and etch-resistant material protective layer; wherein the insulating ceramic material protective layer is any one of a silicon oxide layer, an aluminum oxide layer, an aluminum nitride layer, and a silicon carbide layer.

[0031] Optionally, the constant resistance film material is a low resistance temperature coefficient material, wherein the low resistance temperature coefficient material is any one of nickel-chromium, nickel-copper, tantalum nitride, and chromium-silicon; the thickness of the constant resistance film is 10nm-3μm.

[0032] Optionally, the metal electrode layer is made of any one of gold, copper, silver, or aluminum; the electrode is prepared using a lift-off process or a patterning process.

[0033] Optionally, the insulating substrate is an insulating rigid substrate.

[0034] Compared to the prior art, the key to the fabrication method in this application lies in the MEMS process compatibility design, which ensures the performance integrity (no failure) and independence (no mutual interference) of the sensing unit and the reference resistor unit during the synchronous fabrication process. Specifically, during the fabrication of the constant-value resistor thin film, the already fabricated temperature-sensitive thin film is protected with a thick photoresist layer (1μm-20μm). A differentiated photoresist polarity design (the polarity of the second photoresist must be opposite to that of the third photolithography) ensures that the photoresist protective layer will not be damaged during the third photolithography process. Existing processes rarely involve the synchronous fabrication and protection of two or more types of sensitive films, and inadequate protection measures can lead to mutual interference and failure of the sensitive film components. Based on a unique sensor structure, this application achieves high-quality integration of two or more types of sensitive films on a single substrate using the above process, with the fabrication process not affecting each other's performance. This solves the technical challenge of integrating thin-film temperature sensing units and thin-film constant-value reference resistor units on a single insulating substrate to form a temperature sensor chip.

[0035] Compared with the prior art, this application has at least one of the following advantages:

[0036] This application provides a design and fabrication method for a wide-temperature-range intelligent temperature sensor, realizing an integrated temperature sensor chip that integrates a high-precision thin-film temperature sensor unit and a thin-film constant-value reference resistor unit. Based on miniaturized MEMS technology, this integrated temperature sensor chip reduces off-chip interconnects, significantly shrinks device size, lowers overall power consumption, and improves response speed. It can also be efficiently cascaded with dedicated temperature measurement integrated circuit chips to achieve rapid temperature sensing and closed-loop control in a wide-temperature-range environment.

[0037] This application provides a reference for addressing the challenges of miniaturization, fast response, and low power consumption in traditional discrete devices, and has potential value in the fields of quantum computing and precision temperature measurement and control in spacecraft cryogenic systems. Attached Figure Description

[0038] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0039] Figure 1 This is a schematic diagram of the device structure and a cascading method of an embodiment 1 of this application;

[0040] Figure 2 This is a process flow diagram of a preparation method according to an embodiment of this application;

[0041] Figure 3 This is a flowchart of the preparation process of a preferred embodiment 1 of this application;

[0042] Figure 4This is a schematic diagram of the device structure and a cascading method of a preferred embodiment 2 of this application;

[0043] Figure 5 This is a schematic diagram of the device structure and a cascading method of a preferred embodiment 3 of this application;

[0044] In the picture:

[0045] 1. Insulating substrate

[0046] 2. Thin-film temperature sensing unit

[0047] 3. Metal electrode layer

[0048] 4. Thin-film constant reference resistor unit

[0049] 5. Gold connecting wire

[0050] 6. Dedicated temperature measurement integrated circuit chip

[0051] 7. Dedicated temperature measurement integrated circuit chip pins

[0052] 8. Ball-mounted solder joints

[0053] 9. Alumina protective layer. Detailed Implementation

[0054] The present application will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application. These all fall within the protection scope of the present application.

[0055] To address the problems of large size, slow response, signal distortion, and inconvenient cascading of traditional discrete temperature sensors and constant reference resistors in integrated circuit applications, this application proposes a wide-temperature-range intelligent temperature sensor design and fabrication method to realize an intelligent temperature sensor that highly integrates a thin-film temperature sensing unit and a thin-film constant reference resistor unit on a monolithic substrate.

[0056] Reference Figure 1 , 4As shown in Figure 5, in this embodiment of the application, the wide-temperature-range intelligent temperature sensor includes an insulating substrate, a thin-film temperature sensing unit, a thin-film constant-value reference resistor unit, and a metal electrode layer. The thin-film temperature sensing unit and the thin-film constant-value reference resistor unit are formed and arranged on the insulating substrate using MEMS technology, and signal transmission is achieved through the metal electrode layer. The thin-film temperature sensing unit includes a temperature-sensitive thin film, and the thin-film constant-value reference resistor unit includes a constant-value resistor thin film. The temperature-sensitive thin film is fabricated on the insulating substrate, and the constant-value resistor thin film is fabricated on the insulating substrate. The temperature-sensitive thin film is connected to the constant-value resistor thin film through the metal electrode layer.

[0057] Traditional interconnections between discrete sensors and reference resistors, as well as the further interconnections between these two parts and integrated circuit chips, rely on a large number of off-chip interconnects. The device structure proposed in this application integrates the first two parts and facilitates cascading and cooperation with chips, offering significant advantages such as small size, elimination of interconnects, and fast response.

[0058] The key advantage of the wide-temperature-range intelligent sensor proposed in this application is that it can be directly functionally integrated and cascaded with subsequently developed dedicated temperature measurement integrated circuit chips. This is achieved by eliminating external wires through a monolithic integrated structure and by implementing functional co-design for the specific electrical interfaces of the temperature measurement integrated circuit chip (such as input range, ADC resolution, and anti-interference requirements). This includes, but is not limited to, precisely matching the resistance range of the constant reference resistor to the signal conditioning range of the temperature measurement integrated circuit chip, optimizing the temperature sensor sensitivity to match the ADC resolution, using metal electrode layout (linewidth / spacing) to suppress parasitic effects and ensure signal integrity, and arranging the cell spacing to suppress thermal crosstalk.

[0059] The sensor fabricated in this application can be used in close collaboration with dedicated temperature measurement integrated circuit chips, providing optimized signal conditioning, digital processing, and interface functions. By cascading the integrated sensor of this application with a dedicated temperature measurement integrated circuit chip, a highly integrated, miniaturized intelligent temperature measurement microsystem can be constructed.

[0060] Reference Figure 2 As shown in one embodiment of this application, a method for fabricating a wide-temperature-range intelligent temperature sensor is provided, comprising:

[0061] S1. Select an insulating substrate and perform cleaning and drying processes;

[0062] S2. A temperature-sensitive thin film is prepared on the insulating substrate using a sensitive thin film preparation process;

[0063] S3. First photolithography: A photolithographic pattern is formed on the temperature-sensitive thin film, and the pattern is etched by an ion beam etching process to obtain the thin film temperature sensing unit;

[0064] S4. After cleaning the photoresist, perform a second photolithography process to pattern the photoresist on the surface of the obtained temperature-sensitive thin film pattern. This serves as a protective layer to prevent the properties of the temperature-sensitive film pattern from being damaged by subsequent processes. The polarity of the photoresist used in this step must be different from that used in the next photolithography process to ensure that the photoresist protective layer in this step will not be removed in the next photolithography step.

[0065] The "next photolithography process" mentioned here refers to the third photolithography step in S6. Before performing the fourth photolithography step in S7, the photoresist protective layer introduced in step S4 and the patterned photoresist formed in step S6 must be removed.

[0066] S5. A constant resistance thin film is prepared on the insulating substrate using a thin film preparation process;

[0067] S6. Third photolithography: a photolithographic pattern is formed on the constant value resistor film, and the pattern is etched by ion beam etching process to obtain the thin film constant value reference resistor unit;

[0068] S7. After cleaning the photoresist, a fourth photolithography is performed to form photolithographic patterns on the insulating substrate, the thin film temperature sensing unit, and the thin film constant value reference resistor unit. Then, a metal electrode layer is prepared at the electrode pattern using a lift-off process or an etching process.

[0069] In other embodiments requiring the simultaneous fabrication of two or more sensitive thin films, the protection method is not limited to photoresist masks; a deposition process can also be used to form a protective layer of etch-resistant materials such as alumina or other insulating ceramics. If such a protective layer (e.g., silicon oxide, alumina, aluminum nitride, silicon carbide) is used, its inherent etch resistance eliminates the need for removal in subsequent processes and eliminates the need for additional protective measures.

[0070] However, patterning the etch-resistant protective layer requires an additional photolithography and etching process between steps S4 and S5. Therefore, directly using photoresist as the protective layer simplifies the process flow and improves process flexibility, but its stability is not as good as the aforementioned etch-resistant material. Specifically, in S4, when using an insulating etch-resistant protective layer, after steps S1-S3, the process includes:

[0071] S4. An etching-resistant protective layer is formed on the surface of the obtained temperature-sensitive thin film pattern using a deposition process;

[0072] S4.1: The etching-resistant material protective layer formed by the deposition process is patterned by photolithography. Photoresist is patterned on the surface of the insulating etching-resistant material, and the pattern is etched by plasma etching or dielectric etching process to obtain the etching-resistant material protective layer (200nm-3μm) to protect the properties of the temperature-sensitive film pattern from being damaged by subsequent processes.

[0073] Step S4.1 is followed by steps S5-S7.

[0074] In some embodiments of this application, the thin-film temperature sensing unit and the thin-film constant reference resistor unit are grown on the surface of an insulating substrate using thin-film fabrication technology and patterned using MEMS processing technology. The thin-film temperature sensing unit (high resistance temperature coefficient) and the thin-film constant reference resistor unit (near-zero resistance temperature coefficient) must simultaneously consider the impact of their layout on temperature field distribution, thermal crosstalk, and electrical signal integrity. The arrangement and linewidth / spacing of the metal electrode layers must match the input impedance, signal transmission protocol, and anti-interference requirements of the dedicated temperature measurement integrated circuit chip.

[0075] In some specific embodiments of this application, the insulating substrate includes, but is not limited to, rigid insulating substrates such as silicon oxide, glass, and sapphire.

[0076] In some specific embodiments of this application, the temperature-sensitive thin film materials include, but are not limited to, transition metal nitride or nitride materials such as zirconium oxynitride and hafnium oxynitride, as well as metal oxides such as manganese, cobalt, and nickel, and metal materials such as platinum.

[0077] In some specific embodiments of this application, the sensitive thin film preparation process includes, but is not limited to, chemical vapor deposition, reactive magnetron sputtering, electron beam evaporation, thick film printing, and other processes.

[0078] In some specific embodiments of this application, the thickness of the temperature-sensitive film is 10nm-500nm. When the thickness of the film is outside this range, the resistance or temperature sensitivity of its temperature sensor will be too high or too low.

[0079] In some specific embodiments of this application, the constant resistance thin film material is a low temperature coefficient of resistance material. Constant resistance thin film materials include, but are not limited to, low temperature coefficient of resistance materials with stable resistance values ​​such as nickel-chromium, nickel-copper, tantalum nitride, and chromium-silicon.

[0080] In some specific embodiments of this application, the thickness of the constant-value resistor film is 10 nm-3 μm. When the film thickness is outside this range, the sheet resistance of the constant-value resistor film will be too large or too small, and the temperature coefficient of resistance will not be easy to control.

[0081] In some specific embodiments of this application, the metal electrode layer material includes, but is not limited to, suitable electrode layer materials with good conductivity such as gold, copper, silver, and aluminum. The metal electrode layer is fabricated using a lift-off process or a patterning process.

[0082] This application utilizes MEMS technology to design and fabricate the aforementioned wide-temperature-range intelligent temperature sensor, achieving the integration of the thin-film temperature sensor unit and the thin-film constant-value reference resistor unit on a single substrate, significantly reducing device size and improving response speed. Combined with a dedicated temperature measurement integrated circuit chip, this application has significant value and broad prospects for realizing high-precision, miniaturized, and modular temperature measurement and control applications over a wide temperature range.

[0083] Example 1

[0084] like Figure 1 The figure shows a schematic diagram of the device structure of a preferred embodiment of this application. The wide-temperature-range intelligent temperature sensor shown in the figure includes: an insulating substrate 1, a thin-film temperature sensing unit 2, a thin-film constant value reference resistor unit 4, and a metal electrode layer 3.

[0085] In this design, insulating substrate 1 is a silicon substrate, thin-film temperature sensing unit 2 is a zirconium oxynitride thin-film temperature sensing unit, and thin-film constant reference resistor unit 4 is a nickel-chromium thin-film constant reference resistor unit. The gold interconnect 5 and pin 7 in the figure are not part of the structure of the sensor device of this application. Pin 7 is a conventional structure in a chip, and gold interconnect 5 is a necessary structure when cascading the device and integrated circuit chip using wire bonding technology.

[0086] The device in this preferred embodiment can be manufactured using a wire bonding process, with gold connecting wires 5 and dedicated temperature sensing integrated circuit chip pins 7 connected to achieve signal transmission and functional cooperation between the device in this preferred embodiment and the dedicated temperature sensing integrated circuit chip 6.

[0087] like Figure 3 The diagram shown is a flow chart of the device fabrication process in this preferred embodiment. The specific fabrication process is as follows:

[0088] S1: As Figure 3 As shown in (a), a temperature-sensitive zirconium oxynitride (ZN) film was deposited on a cleaned and dried silicon substrate using DC reactive magnetron sputtering: the silicon substrate was heated to 320°C, a certain amount of argon gas was introduced, a nitrogen-oxygen mixed gas was introduced at a flow rate of 5.3 sccm, the chamber pressure was adjusted to 0.156 Pa, and a 110W DC power supply was used for magnetron sputtering of the ZN film. The deposited ZN film was purple and approximately 100 nm–120 nm thick.

[0089] S2: As Figure 3 The first photolithography was performed as shown in (b). A 5 μm negative photoresist was spin-coated over the zirconium oxynitride film, pre-baked at 80°C for 5 min, followed by deep ultraviolet light exposure, development, and post-baking at 80°C for 8 min. The zirconium oxynitride temperature-sensitive film was patterned using an ion beam etching process for 30 min to obtain the film temperature sensor unit.

[0090] S3: As Figure 3 As shown in (c), the sample was ultrasonically cleaned for 10 minutes each with acetone, alcohol, and water to remove residual photoresist. After cleaning, the device was first dried with nitrogen gas and then placed in an oven for drying. Subsequently, a second photolithography was performed on the patterned zirconium oxynitride film surface: a 10 μm negative photoresist was spin-coated, pre-baked at 80 degrees Celsius for 5 minutes, followed by deep ultraviolet light exposure, development, and patterning. This photoresist layer was used as a protective layer to ensure that it covered the upper surface and sides of the zirconium oxynitride film, and post-baked at 80 degrees Celsius for 8 minutes.

[0091] S4: As Figure 3 As shown in (d), a nickel-chromium alloy resistance heater film was sputtered on the upper surface of the sample by ion beam sputtering. A nickel-chromium alloy target with an elemental mass ratio of Ni:Cr = 60:40wt% was used, and the process time was 35 min, resulting in a nickel-chromium alloy resistance film with a thickness of 180nm-220nm.

[0092] S5: As Figure 3 As shown in (e), a third photolithography step is performed by spin-coating a 5µm positive photoresist over a nickel-chromium film, pre-baking at 80°C for 5 minutes, followed by deep ultraviolet light exposure, development, and post-baking at 80°C for 8 minutes. Because this step uses a positive photoresist, the negative photoresist protective layer from the second photolithography step in S3 is not removed.

[0093] S6: As Figure 3 As shown in (f), the nickel-chromium resistive film was patterned using an ion beam etching process for 20 minutes.

[0094] S7: As Figure 3 As shown in (g), the nickel-chromium resistive film was patterned using an ion beam etching process for 20 minutes to form a serpentine thin-film constant reference resistor unit. The sample was then ultrasonically cleaned sequentially with acetone, alcohol, and water for 10 minutes each to remove residual photoresist. After cleaning, the device was first dried with nitrogen gas and then placed in an oven for final drying.

[0095] S8: As Figure 3 The fourth photolithography step was performed as shown in (h). A 5 μm positive photoresist was spin-coated over the sample, pre-baked at 80°C for 5 min, followed by deep ultraviolet light exposure, development, and post-baking at 80°C for 8 min. A gold layer (approximately 300 nm thick) was sputtered onto the sample surface using an ion beam sputtering process.

[0096] S9: As Figure 3As shown in (i), a lift-off process is used to remove excess photoresist to obtain interdigitated electrodes and on-chip interconnects with a regular structure and controllable spacing as required by the design. The interdigitated electrode spacing is 50 μm and the linewidth is 25 μm; the on-chip interconnect line width is 50 μm. The prepared sample is then cut to obtain an intelligent temperature sensor integrating a zirconium oxynitride thin film temperature sensor unit and a nickel-chromium thin film constant resistor reference unit.

[0097] S10: Adopting a unidirectional stacked architecture, the temperature sensor and the dedicated temperature measurement integrated circuit chip are efficiently cascaded through wire bonding technology on the metal electrode layer and the electrode of the dedicated temperature measurement integrated circuit chip.

[0098] The device in this embodiment further reduces its size by integrating a thin-film temperature sensor and a thin-film constant reference resistor. This eliminates the large number of off-chip interconnects required for cascading with a dedicated temperature measurement integrated circuit in traditional solutions, significantly improves response speed, and effectively reduces signal transmission delay, laying the foundation for building a complete integrated intelligent temperature measurement microsystem.

[0099] Example 2

[0100] like Figure 4 The figure shows a schematic diagram of the device structure of a preferred embodiment of this application. The temperature sensor chip shown in the figure includes: an insulating substrate 1, a thin film temperature sensing unit 2, a thin film constant value reference resistor unit 4, and a metal electrode layer 3 (electrodes and on-chip interconnects).

[0101] Among them, the insulating substrate 1 is a sapphire substrate, the thin film temperature sensing unit 2 is a chromium oxynitride thin film temperature sensing unit, and the thin film constant value reference resistor unit 4 is a nickel copper thin film constant value reference resistor unit.

[0102] The device in this preferred embodiment can be manufactured using a ball-mounting soldering process, where signal transmission and functional coordination are achieved through the ball-mounting solder joints 8 and the dedicated temperature measurement integrated circuit chip 6.

[0103] The specific preparation process of this preferred embodiment is as follows:

[0104] S1: Depositing a temperature-sensitive chromium oxynitride thin film on a cleaned and dried sapphire substrate using DC reactive magnetron sputtering: The sapphire substrate is heated to 400 degrees Celsius, a certain amount of argon gas is introduced, a nitrogen-oxygen mixed gas with a flow rate of 8.5 sccm is introduced, the chamber pressure is adjusted to 0.13 Pa, and DC magnetron sputtering is used to deposit a chromium oxynitride thin film.

[0105] S2: Perform the first photolithography step. Spin-coat photoresist over the chromium oxynitride (CrO2) film, pre-bake, then expose to deep ultraviolet light, develop, and post-bake. Pattern the temperature-sensitive CrO2 film using ion beam etching for 30 minutes. Remove residual photoresist and clean with acetone.

[0106] S3: After cleaning, the device is first dried with nitrogen gas and then placed in an oven to dry. Subsequently, a second photolithography is performed on the patterned chromium oxynitride temperature-sensitive film surface: spin-coating photoresist, pre-baking, followed by deep ultraviolet light exposure, development, patterning of this photoresist layer as a protective layer to ensure that it covers the upper surface and sides of the zirconium oxynitride film, and post-baking.

[0107] S4: A nickel-copper alloy constant resistance film was sputtered onto the upper surface of the sample using a DC magnetron multi-target co-sputtering process. The ratio of copper to nickel content in the nickel-copper layer was adjusted from 75:25at% to 50:50at% by changing the power ratio during copper and nickel target co-sputtering.

[0108] S5: Perform the third photolithography step by spin-coating photoresist over a nickel-copper constant-value resistor film, followed by pre-baking, exposure, development, and post-baking.

[0109] S6: A spiral-shaped constant-value reference resistor unit was fabricated by patterning a nickel-copper constant-value resistor film using a lift-off process. The sample was then ultrasonically cleaned sequentially with acetone, alcohol, and water for 10 minutes each to remove residual photoresist. After cleaning, the device was first dried with nitrogen gas and then placed in an oven for final drying.

[0110] S7: Perform the fourth photolithography step. Spin-coat a 5µm positive photoresist onto the sample, pre-bake at 80°C for 5 minutes, then expose to deep ultraviolet light, develop, and post-bake at 80°C for 8 minutes. Sputter a chromium / gold layer (approximately 30 / 300nm thick) onto the sample surface using ion beam sputtering. Use a lift-off process to remove excess photoresist to obtain the required structurally regular, well-spaced interdigitated electrodes and on-chip interconnects. The interdigitated electrode spacing is 50µm, and the linewidth is 25µm; the on-chip interconnect linewidth is 50µm. Cut the prepared sample to obtain the intelligent temperature sensor of this preferred embodiment.

[0111] S8: It adopts a reverse stack-up architecture, and efficiently cascades the intelligent temperature sensor and the dedicated temperature measurement integrated circuit chip through a ball bonding process on the metal electrode layer and the electrode of the dedicated temperature measurement integrated circuit chip.

[0112] The device in this embodiment integrates a thin-film temperature sensor and a thin-film constant reference resistor, further reducing its size and eliminating the large number of off-chip interconnects required for cascading with a dedicated temperature measurement integrated circuit in traditional solutions. This significantly improves response speed and effectively reduces signal transmission delay, laying the foundation for building a complete integrated intelligent temperature measurement microsystem.

[0113] Example 3

[0114] like Figure 5 The figure shows a schematic diagram of a device structure according to a preferred embodiment of this application. The temperature sensor shown in the figure includes: an insulating substrate 1, a thin-film temperature sensing unit 2, a metal electrode layer 3, a thin-film constant reference resistor unit 4, and an alumina protective layer 9. The alumina protective layer 9 is located above the thin-film temperature sensing unit 2 and can be fabricated using a deposition process.

[0115] Among them, the insulating substrate 1 is a silicon oxide substrate, the thin film temperature sensing unit 2 is a zirconium nitride thin film temperature sensing unit, and the thin film constant value reference resistor unit 4 is a nickel copper chromium thin film constant value reference resistor unit.

[0116] The device in this preferred embodiment can be manufactured using a wire bonding process, with gold connecting wires 5 and dedicated temperature sensing integrated circuit chip pin electrodes 7 connected together, thereby enabling signal transmission and functional cooperation between the device in this preferred embodiment and the dedicated temperature sensing integrated circuit chip 6.

[0117] The specific preparation process of this preferred embodiment is as follows:

[0118] S1: Titanium / gold electrodes and interconnects (approximately 30 / 300 nm thick) are deposited on a cleaned and dried silicon oxide substrate using electron beam evaporation. Subsequently, the desired metal electrode layer is fabricated using an ion beam etching process.

[0119] S2: Spin-coating photoresist, pre-baking, exposure, development, and patterning of the photoresist layer. A zirconium nitride temperature-sensitive film is prepared on the sample surface by DC reactive magnetron sputtering: the substrate temperature is heated to 400 degrees Celsius, and a certain amount of argon and nitrogen gas are introduced respectively. A zirconium nitride temperature-sensitive film is deposited using DC magnetron sputtering.

[0120] S3: Photoresist is spin-coated over the zirconium nitride temperature-sensitive film, pre-baked, then exposed to deep ultraviolet light, developed, and post-baked. The zirconium nitride temperature-sensitive film is patterned using an ion beam etching process to fabricate the thin-film temperature sensor unit. Residual photoresist is then removed, and the film is cleaned with acetone and dried.

[0121] S4: Deposit a 300nm thick aluminum oxide protective film on the thin film temperature sensor unit, and the protective film is located above the zirconium nitride temperature sensitive film.

[0122] S5: Photoresist is spin-coated over the alumina protective film, followed by pre-baking, exposure, development, and post-baking. The alumina protective layer is then prepared using plasma metal etching. Residual photoresist is removed by ultrasonic cleaning for 3 minutes each with acetone, anhydrous ethanol, and deionized water, and the sample is then dried.

[0123] S6: A copper, nickel, and chromium alloy constant resistance film is sputtered above the sample using a DC magnetron multi-target co-sputtering process. The resistivity and temperature coefficient of resistance of the constant resistance film are adjusted by changing the power ratio during the co-sputtering of the copper, nickel, and chromium targets.

[0124] S7: Photoresist is spin-coated over the constant-value resistor film, followed by pre-baking, exposure, development, and post-baking. Then, an ion beam etching process is used to pattern the film, fabricating a ring-shaped thin-film constant-value reference resistor unit. The prepared sample is cut to obtain the intelligent temperature sensor according to this preferred embodiment.

[0125] S8: Adopting a unidirectional stacked architecture, the intelligent temperature sensor and the dedicated temperature measurement integrated circuit chip are efficiently cascaded through wire bonding technology on the metal electrode layer and the electrode of the dedicated temperature measurement integrated circuit chip.

[0126] This application achieves a breakthrough in the performance of resistive thin films for the first time. It is the first to integrate a high-precision thin-film temperature sensing unit and a thin-film constant value reference resistor unit on a single substrate. Through coplanar integration design, the interconnecting wires of the discrete devices of sensor and resistor are eliminated, reducing size, noise and delay. At the same time, through MEMS process compatibility design, the performance integrity (no failure) and independence (no mutual interference) of the sensing unit and the reference resistor unit during the synchronous fabrication process are ensured.

[0127] exist Figure 1 and Figure 5 The image shows a cascaded wire bonding method. Figure 4 The diagram illustrates a ball-mounted cascading method. Cascading methods and processes with chips include, but are not limited to, wire bonding, ball-mounted soldering, and other suitable methods. The schematic diagram is shown to illustrate and emphasize the functional connection and ease of cascading between the device of this application and an application-specific integrated circuit.

[0128] The specific embodiments of this application have been described above. It should be understood that this application is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the substantive content of this application. The above-described preferred features can be used in any combination without conflict.

Claims

1. A wide temperature range intelligent temperature sensor, characterized in that, It comprises: an insulating substrate, a thin-film temperature sensing unit, a thin-film constant reference resistance unit and a metal electrode layer, the thin-film temperature sensing unit and the thin-film constant reference resistance unit are formed on the insulating substrate by a MEMS process, and signal transmission is realized through the metal electrode layer; wherein the thin-film temperature sensing unit comprises a temperature-sensitive thin film, and the thin-film constant reference resistance unit comprises a constant resistance thin film, the temperature-sensitive thin film is prepared on the insulating substrate, the constant resistance thin film is prepared on the insulating substrate, and the temperature-sensitive thin film is connected with the constant resistance thin film through the metal electrode layer.

2. The wide-temperature-range smart temperature sensor of claim 1, wherein, The wide-temperature-range intelligent temperature sensor is an integrated temperature sensor chip integrating a thin-film temperature sensing unit and a thin-film constant reference resistance unit on a single insulating substrate.

3. The wide-temperature-range smart temperature sensor of claim 2, wherein, In the single-chip integrated temperature sensor chip, the thin-film temperature sensing unit and the constant reference resistance unit are integrated to reduce signal delay and noise caused by external connecting wires; the metal electrode layout and electrical interface characteristics of the metal electrode layer realize cascading with a special temperature measurement ASIC chip to construct a closed-loop temperature control system.

4. The wide-temperature-range smart temperature sensor of claim 1, wherein, The wide-temperature-range refers to a temperature range of 4.2K-300K.

5. The wide-temperature-range smart temperature sensor of claim 1, wherein, It also comprises a deposited insulating etch-resistant material protective layer above the thin-film temperature sensing unit; The insulating etch-resistant material protective layer is any one of a silicon oxide layer, an aluminum oxide layer, an aluminum nitride layer and a silicon carbide layer.

6. A method of manufacturing a wide-range smart temperature sensor according to any one of claims 1 to 5, characterized in that, It comprises: S1. Select an insulating substrate and perform cleaning and drying treatment; S2. On the insulating substrate, a temperature-sensitive thin film is prepared by a sensitive thin film preparation process; S3. First photoetching is performed to form a photoetching pattern on the temperature-sensitive thin film, and an etching pattern is formed by an ion beam etching process to obtain a thin-film temperature sensing unit; S4. After cleaning the photoresist, second photoetching is performed to pattern the photoresist on the surface of the obtained temperature-sensitive thin film, which serves as a protective layer to protect the properties of the temperature-sensitive film pattern from being destroyed by subsequent processes; The polarity of the photoresist in this step must be different from that of the photoresist used in the next photoetching process in S6, so as to ensure that the photoresist protective layer in this step will not be removed in the next photoetching step; S5. On the insulating substrate, a constant resistance thin film is prepared by a thin film preparation process; S6. Third photoetching is performed to form a photoetching pattern on the constant resistance thin film, and an etching pattern is formed by an ion beam etching process to obtain a thin-film constant reference resistance unit; S7. After cleaning the photoresist, fourth photoetching is performed to form a photoetching pattern on the insulating substrate, the thin-film temperature sensing unit and the thin-film constant reference resistance unit, and a metal electrode layer is prepared at the electrode pattern by a lift-off process or an etching process.

7. The method of claim 6, wherein: In S4, an insulating etch-resistant material protective layer is used instead of a photoresist protective layer; When the insulating etch-resistant material protective layer is used, after steps S1-S3, it comprises: S4. An etch-resistant material protective layer is formed on the surface of the obtained temperature-sensitive thin film pattern by a deposition process; S4.1: performing a photolithography on the etching-resistant material protection layer formed by the deposition process, performing a photoresist patterning on the surface of the insulating etching-resistant material, and performing an etching patterning by using a plasma etching or a dielectric etching process to obtain the etching-resistant material protection layer for protecting the properties of the temperature-sensitive film pattern from being destroyed by subsequent processes; After step S4.1, steps S5-S7 are performed.

8. The method of claim 6 or 7, wherein: The temperature-sensitive film is made of a transition metal nitride and oxynitride material prepared by using a transition metal element, and a temperature-sensitive metal oxide and platinum metal material; wherein: The transition metal element includes any one of titanium, zirconium, hafnium, vanadium, niobium, tantalum or chromium; The thickness of the temperature-sensitive film is 10nm-500nm.

9. The method of claim 6 or 7, wherein: The preparation process of the temperature-sensitive film includes any one of a chemical vapor deposition, a pulsed laser deposition, an electron beam evaporation, a reactive magnetron sputtering and a thick film printing process.

10. The method of claim 6 or 7, wherein: The constant resistance film material is a low resistance temperature coefficient material, wherein the low resistance temperature coefficient material is any one of nickel-chromium, nickel-copper, tantalum nitride and chromium-silicon, and the thickness of the constant resistance film is 10nm-3μm; The metal electrode layer is made of any one of gold, copper, silver and aluminum, and the electrode is prepared by using a Lift-off process or a patterning process; The insulating substrate is an insulating rigid substrate.

Images