Platinum resistor chip for high-altitude temperature observation and FIB punching process

Abstract

The invention relates to meteorological instruments and microelectronic technologies, in particular to a platinum resistor chip for high-altitude temperature observation and an FIB punching process, the platinum resistor chip comprises a rectangular base and a platinum resistance wire, and the rectangular base is of a horizontal frame structure; the platinum resistance wire is installed on the rectangular base, and continuous holes are formed in the part, located on the hollowed-out area, of the platinum resistance wire in the length direction of the platinum resistance wire; the holes in the platinum resistance wire in the hollow area are divided into a middle area and auxiliary areas at the two ends of the middle area; the hole spacing of the middle area is smaller than that of the auxiliary area; and two ends of the platinum resistance wire are leads. The mass of the platinum resistance wire is reduced, the ventilation quantity is increased, so that the platinum resistance wire cannot be damaged due to excessive wind power, meanwhile, the cross sectional area of current is reduced, the resistance value of the platinum resistor is increased, and the temperature influence caused by different materials between the platinum resistor and a bonding pad or a wire except for solar radiation is greatly reduced; therefore, the measurement of the high-altitude environment temperature is more accurate, and the response rate is higher.

Description

Technical Field

[0001] The present invention relates to the fields of meteorological instrument technology, microelectronics technology, aerospace, 6G communication, and in particular to a platinum resistance chip and FIB punching process for high-altitude air temperature observation. Background Art

[0002] In the prior art, temperature sensors used for high-altitude air temperature observation must meet the following performance requirements: large surface-to-volume ratio to improve response rate; good component linearity, high measurement accuracy and excellent resistance stability, not easily affected by physical and chemical factors; small self-heating effect under high voltage conditions; small error due to solar radiation; high reliability in harsh environments such as strong winds, and components are not easily damaged by strong convection; and high reliability of welding connections. However, the current mainstream temperature sensor types include rod thermistors, bead thermistors and platinum resistors, all of which have certain technical limitations and are difficult to meet the performance requirements of temperature sensors for high-altitude air temperature observation.

[0003] Specifically, rod-shaped thermistors have a large volume and a small surface-to-volume ratio, which results in a slow response rate, a significant self-heating effect, low measurement accuracy, and a large impact on solar radiation errors. Bead-shaped thermistors are small in size, with a diameter usually on the order of 1 mm. Although the self-heating effect is relatively small, their surface-to-volume ratio and response rate are insufficient, the measurement accuracy is limited, and they are significantly affected by solar radiation errors. In addition, bead-shaped thermistors are prone to lead damage or stretching deformation due to strong convection environments during flight, thus affecting reliability. Platinum resistors have excellent resistance stability and linearity. Platinum materials are not easy to react chemically with oxygen molecules or water molecules in the air, and have high measurement accuracy and small solar radiation errors. However, platinum resistors have a large self-heating effect and a slow response rate, making it difficult to fully meet the requirements of high-altitude air temperature observations.

[0004] In order to solve the above problems, the present invention proposes a new type of platinum resistor chip, which adopts etching technology on the surface of platinum resistor wire. By etching the platinum resistor wire, the current cross-sectional area can be increased, the resistance value can be increased, and the volume can be reduced, thereby improving the surface-to-volume ratio, effectively reducing the self-heating effect and shortening the response time. The etched platinum resistor surface has excellent airflow heat dissipation capacity, and the high reflectivity of the platinum material to solar radiation further reduces its solar radiation error. In addition, the design shows good ventilation effect in strong convective weather, components are not easily damaged, and reliability is significantly improved.

[0005] However, traditional microelectronic lithography technology has limitations when processing slender and small-sized materials such as platinum resistance wire. The photolithography process usually requires multiple complex steps such as base film treatment, glue coating, pre-baking, exposure, development, hard film, development inspection, etching, degumming and final inspection, and is mainly suitable for sheet material processing, and it is difficult to achieve high-precision etching of platinum resistance wire. In this context, focused ion beam (FIB) technology has significant advantages over traditional photolithography technology. FIB technology can directly act on the surface of platinum resistance wire and use focused ion beam to achieve precise etching on a microscale, which is particularly suitable for the processing of such slender and small-sized materials. To this end, the present invention utilizes FIB technology to etch the platinum resistance wire, fundamentally overcomes the limitations of traditional photolithography technology, and significantly improves the comprehensive performance of the platinum resistance chip, thereby meeting the multiple performance requirements of high-altitude air temperature observation. Summary of the invention

[0006] The purpose of the present invention is to solve the problems of poor heat dissipation capacity of traditional microelectronic processes and self-heating effect and long response time of mainstream temperature sensors in the prior art. The present invention discloses a platinum resistance chip and FIB drilling process for high-altitude air temperature observation.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A platinum resistance chip for high-altitude air temperature observation comprises a rectangular base and a platinum resistance wire, wherein the rectangular base is a horizontal frame structure, the middle of which is a hollow area, and the periphery is a frame; the platinum resistance wire is installed on the rectangular base, and both ends of the platinum resistance wire are fixed on the frame of the rectangular base, a portion of the platinum resistance wire located on the hollow area is provided with a plurality of continuous holes 1 along its length direction, and a portion of the platinum resistance wire located on the rectangular base frame is also provided with holes 2 along its length direction;

[0009] The holes on the platinum resistance wire in the hollow area are divided into a middle area and attached areas at both ends of the middle area; the spacing between the holes in the middle area is smaller than the spacing between the holes in the attached area;

[0010] Hole 1 and Hole 2 are arranged to penetrate the platinum resistance wire. Hole 1 and Hole 2 are generated by FIB technology, and the opening direction is the radial direction of the platinum resistance wire.

[0011] A welding pad is provided between the platinum resistance wire and the rectangular base frame, and the welding pad includes a bottom layer, a middle layer, and a top layer. The bottom layer is made of Ti and is in fixed contact with the oxide on the surface of the rectangular base. The middle layer is made of Pt, and the end of the platinum resistance wire is placed in the middle layer. The top layer is made of Au, and the top layer has a placement groove for accommodating the end of the platinum resistance wire, and the placement groove is filled with platinum slurry.

[0012] As a further preferred solution, the diameter of the platinum resistance wire is less than 0.02 mm, and the diameter of the hole is between 0.01 mm and 0.015 mm.

[0013] As a further preferred embodiment, the number of holes per unit length in the middle zone is P1, P1=N1 / (3.15cm), N1 is the number of holes in the middle zone; the number of holes per unit length in the auxiliary zone is P2, P2=N2 / (0.49cm), N2 is the number of holes in the auxiliary zone; P1 is 1.5 to 2 times of P2.

[0014] As a further preferred solution, a pad is provided at each contact position between the platinum resistance wire and the rectangular base frame, the pad is connected and fixed to the platinum resistance wire via platinum paste, and the second hole is also filled with platinum paste.

[0015] As a further preferred solution, the opening direction of the hole is vertical.

[0016] As a further preferred solution, the rectangular base is made of silicon wafer, ceramic and glass materials; when silicon is used as the base material, an oxide film will be generated on the surface, and the oxide film has good insulation properties.

[0017] A FIB drilling process for a platinum resistance chip for high-altitude air temperature observation comprises the following steps:

[0018] Step 1: Before FIB processing, remove the oxides, grease and other tiny contaminants on the surface of the platinum resistance wire and clean it with anhydrous ethanol or equivalent organic solvent to ensure the sample is clean;

[0019] Step 2: Use a non-conductive adhesive method to fix the platinum resistance wire on a special carrier to ensure the stability of the sample during processing;

[0020] Step 3: During the processing, in order to reduce the accumulation of thermal effects, start the liquid nitrogen cooling system to keep the sample temperature between -150℃ and -196℃. Use the temperature sensor to monitor the local temperature of the sample in real time to ensure that the sample temperature is always below -150℃ during the processing;

[0021] Step 4: Set the initial acceleration voltage to 20 kV and the initial ion beam current to 5 pA; during the processing, the ion beam current gradually increases with time and eventually reaches 20 pA to 30 pA to reduce processing time and material damage while ensuring processing accuracy; the specific value of the final current is adjusted according to the hole depth or material removal rate;

[0022] Step 5: Adopt a layer-by-layer removal strategy, and control the thickness of each layer removed between 10-20nm. Use high-resolution images to monitor the shape and depth of the holes in real time to ensure that the processing accuracy meets the design requirements;

[0023] Step 6: After processing, stop the cooling system and let the sample gradually return to room temperature. After the temperature stabilizes, use a scanning electron microscope to check the hole morphology to ensure processing accuracy. At the same time, test the electrical properties of the platinum resistance wire to ensure that the resistance change is within an acceptable range. If necessary, the hole position and depth can be further optimized.

[0024] As a further preferred solution, in step 4, when etching using FIB, the acceleration voltage of the focused ion beam microscope instrument is set to a constant 20 kV, the initial ion beam current is set to 5 pA, and the ion beam current gradually increases with time, and its variation law satisfies the following formula: Where I0 is the initial ion beam current, T is the total time required to etch a complete hole, α is the coefficient that controls the steepness of the ion beam current increase curve, and β is the coefficient that controls the final ion beam current. When t = T, the final ion beam current can reach (1 + β) times the initial ion beam current. This formula can ensure processing accuracy through a smaller ion beam current in the early stage, and gradually increase the ion beam current as time goes by to improve etching efficiency while reducing potential damage to the material structure.

[0025] Beneficial Effects

[0026] Compared with the prior art, the advantages of the present invention are:

[0027] First of all, this design uses a new microelectronic technology FIB (focused ion beam) process to generate a series of equally spaced holes in the suspended part of the platinum resistance wire. Compared with the previous complex process of photolithography, FIB technology does not require the use of masks and photosensitive adhesive layers, which simplifies the process flow, reduces pollution, and improves the reliability and yield of the device. By generating holes on the platinum resistance wire, the mass of the platinum resistance wire is reduced, the ventilation volume is increased, so that the platinum resistance wire will not be damaged due to excessive wind force, and the cross-sectional area of ​​the current is reduced, thereby increasing the resistance value of the platinum resistor, and greatly reducing the temperature effect caused by different materials between the platinum resistor and the pad or the wire other than solar radiation, making the measurement of high-altitude ambient temperature more accurate and faster in response; secondly, the use of FIB technology also solves the problem of not being able to generate holes by photolithography on a platinum resistance wire with a diameter of only 0.02mm; secondly, there are holes only in the suspended part, and there is no contact between the platinum resistance wire and the base. Punching means that the resistance of the contact point between the platinum resistance wire and the base is extremely small compared to the suspended part of the platinum resistance wire, which greatly reduces the impact of damage to the overall resistance caused by laser heating welding on both ends of the platinum resistance wire; at the same time, the method of punching holes in the suspended part of the platinum resistance wire will only affect the strength of the middle section, and has little impact on the two ends of the platinum resistance wire that are under great stress. In addition, sufficient space is left between the suspended part and the root to avoid the platinum resistance wire being vulnerable due to punching, which improves the stability of the chip structure to a certain extent; in addition, the hollow base structure in the middle increases heat dissipation while greatly reducing the impact of heating at the root of the platinum resistance wire on the overall resistance value. Therefore, the impact of self-heating effect and slow response rate on the measurement results is greatly reduced. At the same time, compared with rod-shaped thermistors and bead-shaped thermistors, this design has a greatly reduced volume, higher measurement accuracy, improved absorption power of solar radiation, and higher strength stability in structure.

[0028] When the FIB (focused ion beam) process is used to punch holes at the end of the platinum resistance wire, not only can the resistance value of the platinum resistance wire be further increased, but more importantly, the stability of the entire structure can be significantly improved. This is because in the process of punching holes in the platinum resistance wire, the focused ion beam will, to a certain extent, achieve local welding of the platinum resistance wire and the pad, strengthening its mechanical and electrical connection. In addition, utilizing the good adhesion of the platinum slurry, the platinum slurry can effectively fill the holes at the end, and after solidification, form a solid structural support, thereby further enhancing the overall mechanical stability of the chip. At the same time, the platinum slurry contains a large number of platinum particles with excellent conductive properties. After welding and curing, these platinum particles can form a stable and low-impedance conductive path, which significantly improves the electrical contact effect and ensures the long-term reliability of the electrical connection.

[0029] The pad adopts a three-layer structure of Au / Pt / Ti, in which the bottom layer is Ti, which acts as an adhesion layer and can provide excellent adhesion properties to ensure that the metal film is firmly attached to the base material, while effectively preventing the Pt layer from diffusing into the base material; the middle layer is Pt, which acts as a diffusion barrier layer and structural support layer, has good corrosion resistance and thermal stability, and has excellent electrical conductivity, thereby ensuring the stability and efficiency of current transmission; the top layer is Au, which has low resistivity, small contact resistance, and excellent electrical conductivity. At the same time, due to its strong oxidation resistance, it can maintain the electrical connection performance of the pad in high humidity and high temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a three-dimensional structural schematic diagram of the present invention;

[0031] Figure 2 is a top view of the present invention;

[0032] Figure 3 It is a schematic diagram of the three-dimensional structure of the platinum resistance wire in the present invention;

[0033] Figure 4 It is a structural diagram of the pad. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0035] like Figure 1 and Figure 2 The chip for high-altitude air temperature observation shown in the figure includes a rectangular base 5 with a hollowed-out groove process in the middle, the rectangular base 5 is a horizontal frame structure, the middle is a hollowed-out area, the periphery is a frame, and a platinum resistance wire 3 is arranged above the rectangular base 5, the diameter of the platinum resistance wire 3 does not exceed 0.02 mm, and a hole 1 is generated along the length direction of the platinum resistance wire 3 in the hollowed-out area by the FIB process, and the diameter of the hole 1 is between 0.01 mm and 0.015 mm.

[0036] The hole 1 on the platinum resistance wire 3 in the hollow area is divided into a middle area and attached areas at both ends of the middle area; the spacing between the holes 1 in the middle area is smaller than the spacing between the holes 1 in the attached area, and the attached area also includes a support area without a hole 1, which increases the stress at both ends of the platinum resistance wire 3 to avoid breakage and damage.

[0037] The number of holes 1 per unit length in the middle area is P1, P1=N1 / (3.15cm), N1 is the number of holes 1 in the middle area; the number of holes 1 per unit length in the auxiliary area is P2, P2=N2 / (0.49cm), N2 is the number of holes 1 in the auxiliary area; P1 is between 1.5 times and 2 times of P2.

[0038] The portion of the platinum resistance wire 3 located on the frame of the rectangular base 5 is also provided with a hole 2 along the length direction. Hole 1 and hole 22 are arranged to penetrate the platinum resistance wire 3. Hole 1 and hole 22 are generated by the FIB punching process of microelectronic technology. The opening direction is the radial direction of the platinum resistance wire 3 and is perpendicular to the inner bottom surface of the rectangular base 5. When the rectangular base 5 is placed horizontally, the opening direction of hole 1 and hole 22 is vertical.

[0039] Furthermore, the platinum resistance wire 3 and the rectangular base 5 are connected by means of a welding pad 4. The specific process is to firstly apply a drop of platinum slurry at the contact point between the platinum resistance wire 3 and the rectangular base 5, and at the same time, use a laser to utilize the good adhesion of the platinum slurry to combine the two ends of the platinum resistance wire 3 with the welding pad, thereby enhancing the stability of the structure and reducing the damage to the platinum resistor caused by the laser.

[0040] Specifically, a pad 4 is provided between the platinum resistance wire 3 and the frame of the rectangular base 5, and the pad 4 includes a bottom layer 4-1, an intermediate layer 4-2, and a top layer 4-3. The material of the bottom layer 4-1 is Ti, and it is in fixed contact with the oxide on the surface of the rectangular base 5. The material of the intermediate layer 4-2 is Pt, and the end of the platinum resistance wire 3 is placed in the intermediate layer 4-2. The material of the top layer 4-3 is Au, and the top layer 4-3 has a placement groove for accommodating the end of the platinum resistance wire 3. The placement groove is filled with platinum paste 4-4, and the platinum paste 4-4 can overflow. The platinum paste 4-4 is also filled into the hole 22. On the one hand, it can further increase the resistance value. On the other hand, after the platinum resistance wire 3 and the rectangular base 5 are initially welded by using FIB, the hole 22 is fixed by filling the platinum paste 4-4 to form a more solid structure.

[0041] The present invention adopts the above-designed platinum resistance wire 3 and rectangular base 5 to replace the bead-shaped thermistor, rod-shaped thermistor and platinum thermal resistor in the prior art.

[0042] The rectangular base 5 and the platinum resistance wire 3 are both placed horizontally. The platinum resistance wire 3 and the rectangular base 5 are connected to the pad 4 through a platinum paste 4-4 (not shown in the figure).

[0043] The penetration direction of hole 1 and hole 2 is perpendicular to the upper surface of the rectangular base 5. The holes arranged at intervals are generated on the platinum resistance wire 3 by the FIB process, which increases the ventilation volume and improves the thermal conductivity response rate while reducing the cross-sectional area of ​​the current flowing through the suspended part of the platinum resistance wire, thereby enhancing the resistance of the platinum resistance wire, which means that the voltage generated by the same current flowing through is greater, and reduces the influence of other factors other than solar radiation, such as the PN junction generated by the contact between different materials on the voltage on the platinum resistance wire 3, thereby improving the accuracy of temperature measurement. Secondly, the resistance of the platinum resistance wire 3 where there are holes is much greater than the resistance of the parts without holes at both ends that are in contact with the rectangular base 5. Therefore, if the temperature changes at both ends due to damage or other factors have little effect on the overall platinum resistance wire 3, the accuracy of temperature measurement is further improved. At the same time, the method of drilling holes in the suspended part of the platinum resistance wire 3 will only affect the strength of the middle section, and has little effect on the two ends that are under greater stress and are easily damaged, and avoids damage to the structure caused by the holes, leaving sufficient space at the suspended part and the root, which makes the structure stable to a certain extent.

[0044] In the process of drilling holes in platinum resistance wire using focused ion beam (FIB) technology, it is concerned that the ion beam may damage the structure of the platinum resistance wire. Therefore, in order to ensure the processing effect while maximally protecting the resistance wire, two key measures were taken during the design process.

[0045] First, in order to reduce the physical impact on the platinum resistance wire, the ion beam current is constrained so that it increases gradually over time. The initial low current setting helps to improve processing accuracy and avoid deformation or peeling of the material structure caused by continuous high current. In addition, the strategy of gradually increasing the ion beam current can effectively reduce the interference with the tiny structures around the platinum resistance wire. At the same time, with the gradual increase in the ion beam current, the processing efficiency is significantly improved in the later stage, reducing the total time required for processing. Because FIB equipment is extremely expensive, excessive power may cause the equipment to overheat and increase maintenance costs. Therefore, choosing a low initial ion beam current helps reduce equipment losses. In addition, appropriately increasing the ion beam current when etching approaches the target depth can increase the temperature of the etched area and enhance the welding effect, thereby promoting a tighter bond between the pad and the wire at the microscopic level.

[0046] Secondly, in order to further reduce the thermal effect caused by the ion beam, a low-temperature cooling system (such as liquid nitrogen cooling) is introduced into the FIB processing environment. The low-temperature environment can effectively suppress the heat accumulation generated during focused ion beam processing, thereby avoiding the microstructural annealing or recrystallization phenomenon caused by the local high temperature of the platinum resistance wire. This not only avoids the material reconstruction caused by the temperature increase, but also ensures that the electrical properties of the platinum resistance wire are stably maintained during the processing process.

[0047] Through these optimized designs, the processing accuracy is improved while the structure and electrical properties of the platinum resistance wire are effectively protected, enabling it to better perform its intended function in subsequent applications.

[0048] The specific steps are as follows:

[0049] Step 1: Sample preparation

[0050] 1. Before FIB processing, the oxides, grease and other tiny contaminants on the surface of the platinum resistance wire should be removed. Usually, anhydrous ethanol or equivalent organic solvents can be used for cleaning to ensure the cleanliness of the sample.

[0051] 2. Fix the platinum resistance wire on a special stage to ensure the stability of the sample during processing. Use non-conductive adhesives such as epoxy resin or non-residue adhesive methods to avoid affecting the processing accuracy and electrical measurement results.

[0052] Step 2: Cooling system setup

[0053] 1. To suppress the accumulation of thermal effects during FIB processing, a liquid nitrogen cooling system can be used during processing. The temperature can be maintained between -150°C and -196°C (close to the temperature of liquid nitrogen) to ensure effective heat dissipation.

[0054] 2. When the cooling system is turned on, the local temperature of the sample is monitored by a temperature sensor to ensure that the sample temperature does not exceed -150°C during processing to avoid microstructural changes caused by thermal stress.

[0055] Step 3: Preset ion beam parameters

[0056] 1. When performing micro-hole processing of platinum resistance wire, the initial ion beam current is set to 5pA. As time goes by, the ion beam current size satisfies It can effectively reduce the physical impact on the platinum resistance wire in the initial processing stage and ensure the high precision of the micro-hole shape and size.

[0057] 2. Usually, the acceleration voltage during FIB processing is around 30kV, but for fine structures such as platinum resistance wire, it can be appropriately reduced to 20kV to further reduce the risk of damage to the material structure. Keeping the acceleration voltage unchanged during processing helps avoid uneven processing or deformation caused by voltage fluctuations.

[0058] Step 4: Focused Ion Beam Drilling

[0059] 1. Adopting a layer-by-layer removal processing strategy, when micro-hole engraving is performed on the surface of the platinum resistance wire, the thickness of each layer removed is controlled within 10-20nm. Layer-by-layer processing can ensure the accuracy of the micro-hole shape and reduce the impact of processing on the microstructure of the resistance wire.

[0060] 2. Real-time monitoring of the shape and depth of processing to ensure that the hole size meets the design requirements. Using high-resolution image monitoring (such as FIB-SEM combined system) can accurately control the shape of the hole and the depth of processing.

[0061] Step 5: Follow-up processing and inspection

[0062] 1. Stop the cooling system and allow the sample to gradually return to room temperature. After the sample temperature stabilizes, use a scanning electron microscope (SEM) or other methods to check the morphology of the holes to confirm whether the processing accuracy meets the requirements.

[0063] 2. Finally, the electrical properties of the platinum resistance wire are tested to ensure that there is no significant change in resistance during the processing. If necessary, the hole position and depth can be further optimized in this step.

[0064] In the present invention, the base 5 is made of silicon wafer, ceramics, glass and other materials, which can effectively reduce the diameter radiation of the sun and improve the accuracy of the chip in measuring temperature. Insulating oxide can be formed on the surface of the silicon wafer to improve the insulation performance of the electrical appliance.

[0065] It has been verified by simulation experiments that under the same environmental conditions, the present invention can reduce the error of temperature measurement to the order of 0.02°C, while the error of traditional platinum resistance high-altitude temperature measurement is about 0.1°C. It can be seen that the temperature data measured by the present invention has higher accuracy.

[0066] In high-altitude environments, the temperature measurement accuracy of the radiosonde faces many challenges, especially the influence of solar radiation. The high stability and high response rate of this design can greatly reduce the error caused by solar radiation. When this device is installed on the radiosonde, the resistance value of the platinum resistance wire will change with the change of temperature. The platinum resistance can be connected to the ADC (analog-to-digital converter) chip through a bridge or a precise current source, thereby converting its resistance change into a voltage signal. The single-chip microcomputer (MCU) can collect and calculate the voltage signal and convert it into a temperature value.

[0067] When using a focused ion beam (FIB) for etching, the strategy of keeping the acceleration voltage unchanged and gradually increasing the ion beam current can be adopted to take into account both equipment protection and processing effects. The initial ion beam is set small and gradually increases over time. This method can not only effectively extend the service life of the equipment, but also optimize the etching quality. Since FIB equipment is extremely expensive, excessive power may cause equipment overheating and increase maintenance costs. Therefore, choosing a low initial ion beam current helps reduce equipment loss. In addition, appropriately increasing the ion beam current when etching approaches the target depth can increase the temperature of the etched area and enhance the welding effect, thereby promoting a tighter bond between the pad and the wire at the microscopic level. Its ion beam size can satisfy the following exponential formula:

[0068]

[0069] This formula can ensure that the initial ion beam is small, and as time goes by, the ion beam gradually increases. When t = T, the final ion beam current can reach (1 + β) times the initial ion beam current. I0 is the initial ion beam current, T is the total time required to etch a complete hole, α is the coefficient that controls the steepness of the ion beam current increase curve, and β is the coefficient that controls the final ion beam current size.

[0070] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A platinum resistance chip for high-altitude air temperature observation, characterized in that: The invention comprises a rectangular base (5) and a platinum resistance wire (3), wherein the rectangular base (5) is a horizontal frame structure, with a hollow area in the middle and a frame around it; the platinum resistance wire (3) is installed on the rectangular base (5), and both ends of the platinum resistance wire (3) are fixed on the frame of the rectangular base (5); a portion of the platinum resistance wire (3) located on the hollow area is provided with a plurality of continuous holes (1) along its length direction, and a portion of the platinum resistance wire (3) located on the frame of the rectangular base (5) is also provided with holes (2) along its length direction; The hole one (1) on the platinum resistance wire (3) located in the hollow area is divided into a middle area and auxiliary areas at both ends of the middle area; the spacing between the holes one (1) in the middle area is smaller than the spacing between the holes one (1) in the auxiliary area; The hole 1 (1) and the hole 2 (2) are formed through the platinum resistance wire (3). The hole 1 (1) and the hole 2 (2) are formed by using FIB technology, and the opening direction is the radial direction of the platinum resistance wire (3). A welding pad (4) is provided between the platinum resistance wire (3) and the rectangular base (5) frame, and the welding pad (4) comprises a bottom layer (4-1), an intermediate layer (4-2), and a top layer (4-3). The bottom layer (4-1) is made of Ti and is in fixed contact with the oxide on the surface of the rectangular base (5). The intermediate layer (4-2) is made of Pt. The end of the platinum resistance wire (3) is placed on the intermediate layer (4-2). The top layer (4-3) is made of Au. The top layer (4-3) has a placement groove for accommodating the end of the platinum resistance wire (3), and the placement groove is filled with platinum slurry (4-4).

2. A platinum resistance chip for high-altitude air temperature observation according to claim 1, characterized in that: The diameter of the platinum resistance wire (3) is less than 0.02 mm, and the diameter of the hole (1) is between 0.01 mm and 0.015 mm.

3. A platinum resistance chip for high-altitude air temperature observation according to claim 1, characterized in that: The number of holes (1) per unit length of the middle zone is P1, P1 = N1 / (3.15cm), N1 is the number of holes (1) in the middle zone; the number of holes (1) per unit length of the auxiliary zone is P2, P2 = N2 / (0.49cm), N2 is the number of holes (1) in the auxiliary zone; P1 is 1.5 to 2 times of P2.

4. The platinum resistance chip for high-altitude air temperature observation according to claim 1, characterized in that: A soldering pad (4) is provided at each contact position between the platinum resistance wire (3) and the rectangular base (5) frame. The soldering pad (4) is connected and fixed to the platinum resistance wire (3) via platinum paste. The second hole (2) is also filled with platinum paste (4-4).

5. The platinum resistance chip for high-altitude air temperature observation according to claim 1, characterized in that: The opening direction of the hole 1 (1) is vertical.

6. The platinum resistance chip for high-altitude air temperature observation according to claim 1, characterized in that: The rectangular base (5) is made of a silicon wafer, and an oxide film (5-1) is formed on the surface.

7. A FIB drilling process for a platinum resistance chip for high-altitude air temperature observation according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Before FIB processing, remove the oxides, grease and other tiny contaminants on the surface of the platinum resistance wire (3) and clean it with an organic solvent to ensure that the sample is clean; Step 2: fix the platinum resistance wire (3) on a special carrier by non-conductive adhesion to ensure the stability of the sample during processing; Step 3: During the drilling process, in order to reduce the accumulation of thermal effects, start the liquid nitrogen cooling system to keep the sample temperature between -150℃ and -196℃; use the temperature sensor to monitor the local temperature of the sample in real time to ensure that the sample temperature is always below -150℃ during the processing; Step 4: Set the initial acceleration voltage to 20 kV and the initial ion beam current to 5 pA; during the processing, the ion beam current gradually increases with time and eventually reaches 20 pA to 30 pA to reduce processing time and material damage while ensuring processing accuracy; the specific value of the final current is adjusted according to the hole depth or material removal rate; Step 5: Adopt a layer-by-layer removal strategy, control the thickness of each layer removed between 10-20nm, and monitor the shape and depth of the hole in real time through high-resolution images to ensure that the processing accuracy meets the design requirements; Step 6: After processing is completed, stop the cooling system and allow the sample to gradually return to room temperature. After the temperature stabilizes, use a scanning electron microscope to check the hole morphology to ensure processing accuracy. At the same time, test the electrical properties of the platinum resistance wire to ensure that the resistance change is within an acceptable range. If necessary, further optimize the hole position and depth.

8. The FIB drilling process of a platinum resistance chip for high-altitude air temperature observation according to claim 7, characterized in that: In the step 4, when etching is performed using FIB, the acceleration voltage of the focused ion beam microscope instrument is set to a constant 20 kV, the initial ion beam current is set to 5 pA, and the ion beam current gradually increases over time, and its variation law satisfies the following formula: Where I0 is the initial ion beam current, T is the total time required to etch a complete hole, α is the coefficient that controls the steepness of the ion beam current increase curve, and β is the coefficient that controls the size of the final ion beam current; when t=T, the final ion beam current can reach (1+β) times the initial ion beam current; this formula can ensure processing accuracy through a smaller ion beam current in the initial stage, and gradually increase the ion beam current as time goes by to improve etching efficiency while reducing potential damage to the material structure.

Images