Method for improving imaging uniformity of infrared sensor and infrared sensor

Abstract

The invention provides a method for improving imaging uniformity of an infrared sensor and the infrared sensor, and the method comprises the following steps: S1, forming a polyimide layer on a readout circuit wafer, and carrying out the curing; s2, performing etching in the polyimide layer to form a bridge pier channel until the electrode surface of the readout circuit wafer is exposed; s3, forming a first dielectric layer on the surface of the readout circuit wafer; s4, forming a thermistor part on the first dielectric layer; s5, removing the first dielectric layer on the surface of the electrode to expose the electrode; s6, forming a first metal layer on the surface of the readout circuit wafer; s7, forming a second dielectric layer on the surface of the readout circuit wafer; s8, performing oxygen plasma treatment on the surface of the second dielectric layer under the treatment conditions that the process temperature is 150-200 DEG C and the treatment time is 1-10 minutes; and S9, performing graphical processing on the second dielectric layer, the first metal layer and the first dielectric layer to form a bridge arm structure. According to the method, the uniformity of the key size and the morphology of the bridge arm structure is improved, and the imaging uniformity of the infrared sensor is further improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor integrated circuit manufacturing technology, and in particular to a method for improving the imaging uniformity of an infrared sensor and an infrared sensor. Background Technology

[0002] In the field of infrared sensor technology, imaging uniformity is one of the core indicators determining product performance, directly affecting detection accuracy and user experience. If an image has problems such as uneven brightness or abnormal resolution, it will lead to disordered distribution of light and dark areas and blurred key details, seriously affecting target recognition and scene judgment.

[0003] The bridge (BRG), as the core functional structure of an infrared sensor chip, plays a dual crucial role: first, it connects the thermistor to the underlying ASIC processing circuit, enabling physical and electrical conduction; second, it absorbs external infrared thermal signals and conducts them to the thermistor, providing the basis for thermoelectric signal conversion. This structure typically employs a composite layer design of "dielectric-metal-dielectric," and the uniformity of its critical dimension (CD) and profile directly determines the consistency of the bridge arm resistance value. If there are differences in the bridge arm CD or profile of different pixels within the chip, the voltage output of the corresponding area will show a significant deviation after signal amplification by the ASIC circuit, ultimately leading to imaging abnormalities.

[0004] Therefore, the quality of the bridge arm fabrication process is a core prerequisite for ensuring the imaging uniformity of the infrared sensor. In the entire bridge arm fabrication process, photolithography is the key step determining its CD (crystal depth) and morphological accuracy. Its process stability and uniformity directly affect the consistency of the bridge arm structure, thus limiting the overall imaging performance of the infrared sensor. Existing technologies have significant limitations: improving uniformity by increasing the precision of the photomask fabrication (such as electron beam exposure) is feasible, but electron beam photomasks cost 2-3 times more than ordinary photomasks and cannot solve the problem of bridge arm uniformity within a single exposure shot; replacing I-line equipment with ArF / KrF deep ultraviolet lithography machines optimizes the stability of small linewidth processes, but the procurement cost of DUV lithography machines doubles, limiting the processing capabilities of foundries and the widespread adoption of the technology. Summary of the Invention

[0005] To address all or part of the problems in the prior art, this invention provides a method and an infrared sensor for improving the imaging uniformity of an infrared sensor. This method improves the uniformity of key dimensions and morphology of the bridge arm structure by adding an oxygen plasma treatment process before the bridge arm is patterned, thereby improving the imaging uniformity of the infrared sensor.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for improving the imaging uniformity of an infrared sensor includes the following steps: S1. A polyimide layer is formed on the readout circuit wafer and then cured; S2. Etch bridge channels in the polyimide layer until the electrode surface of the readout circuit wafer is exposed; S3. A first dielectric layer is formed on the surface of the readout circuit wafer; S4. A thermistor portion is formed on the first dielectric layer; S5. Remove the first dielectric layer on the surface of the electrode to expose the electrode; S6. A first metal layer is formed on the surface of the readout circuit wafer; S7. A second dielectric layer is formed on the surface of the readout circuit wafer; S8. Perform oxygen plasma treatment on the surface of the second dielectric layer. The treatment conditions include: process temperature 150-200℃, treatment time 1-10min. S9. The second dielectric layer, the first metal layer, and the first dielectric layer are patterned to form a bridge arm structure.

[0007] In step S8, the oxygen plasma treatment is carried out using a plasma desmearing machine; the treatment conditions also include: radio frequency power of 500-1500W and gas flow rate of 10-30sccm.

[0008] In step S8, the oxygen plasma treatment process temperature is 180°C and the treatment time is 6 minutes.

[0009] In step S9, the bridge arm structure formed is an S-shaped bending structure with a line width of 0.2-0.5μm.

[0010] The first dielectric layer and the second dielectric layer are either silicon nitride or silicon oxide; both the first dielectric layer and the second dielectric layer are deposited by PECVD process.

[0011] The first metal layer is any one of titanium, titanium nitride, and aluminum; the thermistor film layer is vanadium oxide or amorphous silicon; both the first metal layer and the thermistor film layer are deposited by sputtering process.

[0012] In step S2, photoresist is coated on the polyimide layer, and after exposure and development, the bridge pier channel is formed by dry etching.

[0013] In step S4, a thermistor film layer is deposited on the first dielectric layer, and the thermistor portion with a preset pattern is formed by etching.

[0014] In step S9, the lithography process of the patterning process uses a focusing energy matrix to screen the optimal exposure conditions. Specifically, it includes: defining monitoring points within each exposure field of view, with the center of the field of view as the origin (0,0) and the side length of the field of view as L, and setting the coordinates of the five monitoring points as the upper left (-L / 4, +L / 4), upper right (+L / 4, +L / 4), lower left (-L / 4, -L / 4), lower right (+L / 4, -L / 4), and center (0,0); detecting the linewidth and morphology parameters of the bridge arm at each monitoring point; and selecting the focusing value and exposure energy corresponding to when the linewidth deviation and morphology parameters of all monitoring points meet the requirements as the final lithography conditions.

[0015] The present invention also provides an infrared sensor, which is prepared by the method described above for improving the imaging uniformity of the infrared sensor. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of the infrared sensor chip in Embodiment 1 of the present invention.

[0018] Figure 2 This is a top view of the infrared sensor chip in Embodiment 1 of the present invention.

[0019] Figure 3 This is a comparison chart of the process effects of different oxygen bombardment temperatures and times in Example 1 of the present invention.

[0020] Figure 4 This is a schematic diagram of the surface microstructure of the second dielectric layer after being bombarded by a plasma descaling machine in Embodiment 1 of the present invention.

[0021] Figure 5 This is a schematic diagram of the bridge arm structure between the center chip and the edge chip of the wafer when oxygen pretreatment is not performed in Embodiment 1 of the present invention.

[0022] Figure 6 This is a schematic diagram of the bridge arm structure between the center chip and the edge chip of the wafer after oxygen pretreatment in Embodiment 1 of the present invention.

[0023] Figure 7 This is a schematic diagram of the layout of the five-point monitoring system in Embodiment 2 of the present invention.

[0024] Figure 8This is a comparison of scanning electron microscope (SEM) images of the uniformity of bridge arms within the chip under single-point monitoring (left image) and five-point monitoring (right image) in Embodiment 2 of the present invention.

[0025] Figure 9 This is a colorimetric comparison of voltage output (VO) under single-point monitoring (left) and five-point monitoring (right) in Embodiment 2 of the present invention.

[0026] Reference numerals: 1. Readout circuit wafer; 2. Electrode; 3. Polyimide layer; 4. Bridge arm structure; 5. First dielectric layer; 6. First metal layer; 7. Second dielectric layer; 8. Thermistor section; 9. Pier channel. Detailed Implementation

[0027] The technical solutions in specific embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The implementation of the present invention will be described in detail below with reference to specific embodiments.

[0028] Example 1 In the field of MEMS uncooled infrared sensors, a core challenge is uneven image display, specifically manifested as localized differences in key parameters such as brightness and resolution. This leads to image imbalances, blurred details, and an inability to accurately reproduce the infrared signal distribution of the measured object. This problem is directly related to the uniformity of the fabrication of the bridge arms (BRG) in the sensor chip—if the uniformity of the bridge arms within the chip reaches a high standard, the final image can accurately reflect the intensity distribution of the object's infrared signal without the need for algorithmic correction.

[0029] The definition of "uniformity" is clarified here: firstly, the consistency of critical dimensions (CD) and profiles among different bridge arms within the same chip and wafer; secondly, the repeatability of bridge arm structure 4 after photolithography on different batches of wafers. Since the bridge arms of infrared sensors generally have small CD structures, the smaller the linewidth, the more stringent the requirements for uniformity in the photolithography process. In existing technologies, the instability of photolithography exposure and the lack of optimal exposure conditions directly lead to deviations in bridge arm CD and profile, resulting in uneven bridge arm resistance, ultimately causing abnormal voltage output, affecting the realism of the imaging and the user experience.

[0030] This embodiment is applied to the fabrication of uncooled MEMS infrared sensors. The core technical problem to be solved is the insufficient photolithographic stability of the small CD bridge arm structure 4, which leads to differences in the CD and morphology of the bridge arm within the chip, between wafers, and between different batches, ultimately causing the problem of non-uniform imaging. Based on this, this embodiment provides a method to improve the imaging uniformity of infrared sensors, aiming to improve the photolithographic uniformity of the bridge arm structure 4 through surface modification treatment of the dielectric before photolithography.

[0031] Combined with appendix Figure 1 , 2 As shown, the specific process steps of this embodiment are as follows: S1. Polyimide (PI) material is spin-coated onto the surface of readout circuit wafer 1, and then cured to form polyimide layer 3; S2. A positive photoresist is coated on the surface of the polyimide layer 3. After the pattern of the bridge pier channel 9 is defined by exposure and development processes, the polyimide layer 3 is etched by dry etching technology until the surface of the electrode 2 of the readout circuit wafer 1 is exposed, thus forming the bridge pier channel 9. S3. A first dielectric layer 5 is deposited on the surface of the readout circuit wafer 1 and the inner wall of the bridge channel 9 by plasma-enhanced chemical vapor deposition (PECVD). The first dielectric layer 5 is selected from silicon nitride or silicon oxide, and the deposition thickness is 1000Å-2500Å. S4. A thermistor film layer is deposited on the surface of the first dielectric layer 5 using a sputtering process. The material of the thermistor film layer is vanadium oxide or amorphous silicon, and the deposition thickness is 300Å-1000Å. Subsequently, the thermistor part 8 with a preset pattern is formed by photolithography and reactive ion etching (RIE) processes. S5. A portion of the first dielectric layer 5 on the surface of electrode 2 is removed using photolithography and etching processes to expose electrode 2, in preparation for subsequent circuit connections; S6. A first metal layer 6 is deposited on the surface of the readout circuit wafer 1 by sputtering process. The first metal layer 6 is selected from titanium, titanium nitride or aluminum, and the deposition thickness is 500Å-1500Å, serving as the intermediate conductive layer of the bridge arm structure 4. S7. A second dielectric layer 7 is deposited again using the PECVD process. The second dielectric layer 7 is made of the same material as the first dielectric layer 5 (silicon nitride or silicon oxide), and the deposition thickness is 300Å-900Å, forming a "dielectric-metal-dielectric" composite layer structure. S8. An oxygen plasma treatment is performed on the surface of the second dielectric layer 7 using a plasma asher. The core principle is as follows: oxygen molecules are accelerated by an electric field, and oxygen ions and free electrons are generated by electron collisions. The oxygen ions form a nanoscale uneven structure on the dielectric surface, increasing the surface area, and generate oxygen-containing polar groups on the dielectric surface through oxidation. In addition, the bombardment of high-energy oxygen ions promotes the formation of high chemical bond energy Si-O bonds on the dielectric surface. These bonds have extremely high chemical and mechanical stability and can effectively resist potential stress and deformation. These effects work synergistically to provide a solid substrate for subsequent photoresist coating, improve the wettability of the dielectric surface to the photoresist, and suppress the standing wave effect of deep ultraviolet (DUV) light, thereby reducing the linewidth edge roughness. The process conditions for this treatment are: process temperature 150℃-200℃, RF power 500W-1500W, gas flow rate 10sccm-30sccm, and processing time 1min-10min. After debugging and verification of multiple sets of parameters, the stability and uniformity of bridge arm lithography are optimal when the process temperature is 180℃ and the processing time is 6min. S9. The second dielectric layer 7, the first metal layer 6 and the first dielectric layer 5 are sequentially patterned by photolithography and etching to form an S-shaped bent bridge arm with a linewidth of 0.2um-0.5um. This structure design can reduce heat exchange with the outside world and improve the transmission efficiency of infrared thermal signals to the thermistor.

[0032] When the sensor is working, the polyimide layer 3 acts as a support structure, keeping the thermistor 8 away from the substrate. After receiving external infrared thermal signals, the thermistor 8 experiences temperature changes due to signal intensity differences, leading to a change in resistance. The electrical signal is transmitted to the electrode 2 via the bridge arm and pier channel 9, and then converted by the readout circuit to form an infrared thermal image. Because the thermistor 8 is fabricated using a sputtering process, its film thickness uniformity is good; therefore, the consistency of the bridge arm resistance becomes a key factor affecting the uniformity of the final electrical signal output. Figure 2 As shown in the top view of the infrared sensor chip, the bridge arm structure 4 is designed with an S-shaped bend and a small critical dimension (CD). The core purpose of this design is to reduce heat exchange with the outside environment and improve the efficiency of heat signal conduction to the thermistor section 8. In addition, after the thermistor and bridge arm are fabricated, the polyimide layer 3 needs to be released by a gas such as oxygen to form a vacuum area, preventing the polyimide layer 3 from conducting away the heat signal and ensuring that the thermistor section 8 can effectively receive the infrared signal.

[0033] To verify the effectiveness of oxygen plasma treatment, multiple sets of comparative experiments were designed, such as... Figure 3 As shown, some experimental results are as follows: Experimental data show that when the oxygen plasma treatment temperature is 250℃ and the treatment time is 1 min, the bridge arm uniformity is extremely poor; when the treatment temperature is 180℃ and the treatment time is 6 min, the bridge arm uniformity reaches the optimal level. This indicates that low-temperature, long-duration oxygen plasma treatment is more beneficial to the photolithographic stability of the small critical dimension (CD) bridge arm structure 4.

[0034] The core principle can be explained as follows: the underlying dielectric material itself has low surface energy, which easily leads to problems such as localized photoresist peeling and uneven film thickness in photolithography processes with small linewidths; at the same time, the high reflectivity of the dielectric material will induce the standing wave effect of deep ultraviolet (DUV) light, further aggravating the roughness of the linewidth edges. The plasma asher used in this embodiment produces a dual optimization effect through oxygen bombardment: firstly, it forms a nanoscale uneven structure on the dielectric surface, significantly increasing the contact area between the photoresist and the dielectric; secondly, the oxygen free radicals in the plasma oxidize the dielectric surface layer, generating oxygen-containing polar groups, which not only increases the surface energy of the dielectric but also promotes the chemical bonding between the photoresist and the dielectric, effectively improving wettability. A schematic diagram of the surface microstructure of the dielectric after asher bombardment is shown below. Figure 4 As shown. (Attached) Figure 5 , 6 The optimized effects of the pretreatment process are visually presented: Figure 5 Comparing the bridge arm structures 4 of the wafer center and edge die without photolithography preprocessing, it can be seen that after the same exposure, the uniformity of the bridge arms (BRG) at different positions is significantly different, and the bridge arms in the edge area show obvious peeling phenomenon. Figure 6 For the structural comparison after oxygen plasma pretreatment, the uniformity of the bridge arm structure 4 at the center and edge of the wafer tends to be consistent, and the peeling problem is effectively solved.

[0035] Example 2 This embodiment provides a method for improving the imaging uniformity of infrared sensors based on multi-point focusing energy matrix (FEM) screening. Its process flow is the same as that of Embodiment 1. The core difference lies in the photolithography optimal condition screening method in step S9, which aims to improve the uniformity of bridge arms within a single exposure field of view.

[0036] In traditional photolithography, the focusing energy matrix screening only monitors one point at the center of each exposure field of view. This results in only the CD and morphology of the bridge arm in the central region meeting the requirements. Due to differences in focusing and energy distribution at the edge of the field of view, the consistency of the bridge arm structure 4 is poor, leading to uneven resistance and imaging abnormalities. This embodiment improves upon this by setting five monitoring points within each exposure field of view, with the center of the field of view as the origin (0,0). If the side length of the field of view is L (L adapts to the exposure partition of the infrared sensor wafer, ranging from XXmm to XXmm), then the coordinates of the five monitoring points are as follows: upper left (-L / 4, +L / 4), upper right (+L / 4, +L / 4), lower left (-L / 4, -L / 4), lower right (+L / 4, -L / 4), and center (0,0). Each monitoring point corresponds to the effective functional area of ​​the bridge arm structure 4.

[0037] During the photolithography process, the parameters of the focusing energy matrix are set as follows: the focusing value is adjustable from -1.0µm to +0.1µm, with an adjustment step of 0.1µm; the exposure energy is adjustable from 10mJ / cm. 2 Up to 20 mJ / cm 2 Adjust the step size by 0.5 mJ / cm 2 Multiple sets of focusing-energy combination parameters were formed. For each monitoring point, the bridge arm linewidth and morphology parameters were inspected using scanning electron microscopy (SEM). The linewidth deviation from the target design value had to be ≤0.1 μm in absolute value, and the morphology parameters required a sidewall angle of 85°~90°, a surface roughness Ra≤5nm, and a linewidth consistency deviation between the upper and lower surfaces ≤0.08 μm. Finally, the focusing-energy combination that met the requirements for linewidth deviation and morphology parameters at all five monitoring points, with a linewidth variation coefficient ≤3% between monitoring points, was selected as the optimal lithography condition. If multiple suitable combinations existed, the combination with the average linewidth of the five monitoring points closest to the target design value was considered the optimal one.

[0038] Appendix Figure 7 This is a schematic diagram showing the distribution of the five monitoring points. Figure 8 This is a SEM comparison of the uniformity of the bridge arms at five locations within a single die under optimal photolithography conditions when monitoring one point (left image) and five points (right image). Figure 9 This is a colorimetric comparison chart of the corresponding voltage output (VO). Combined with... Figure 8 , 9The comparison results show that when using traditional single-point monitoring, only the bridge arm profile at the center of the chip meets the requirements, while the profiles at the other four locations are poor. These poor profiles manifest as irregular bridge arm cross-sections and deviations in the critical dimensions (CD) of the upper and lower surfaces, leading to inconsistent effective areas of the bridge arm cross-sections. This directly causes uneven bridge arm resistance, ultimately resulting in abnormal voltage output (VO), making the numerical differences between different locations in the VO image significant. However, when using simultaneous monitoring at five points (upper left, upper right, lower left, lower right, and center) and selecting the optimal lithography conditions, the uniformity of the critical dimensions (CD) and profiles of the bridge arms at all locations within the entire chip is significantly improved, and the voltage output (VO) becomes more uniform, ultimately ensuring the effective imaging quality of the infrared sensor.

[0039] Example 3 This embodiment provides an infrared sensor, specifically a MEMS uncooled infrared sensor, which is fabricated using the method for improving the imaging uniformity of infrared sensors described in Embodiment 1 or Embodiment 2. This infrared sensor, through optimized photolithography of the bridge arm structure 4, significantly improves the consistency of bridge arm CD and morphology within the wafer, within the chip, and between different batches of wafers. The bridge arm resistance is uniform and stable, the voltage output deviation after thermoelectric signal conversion is small, and the imaging brightness and resolution are uniform, accurately reflecting the infrared signal distribution of the measured object without requiring additional algorithm correction. It has broad application prospects in fields such as security monitoring, industrial inspection, and medical diagnosis.

[0040] This invention provides two low-cost and easily implemented solutions for improving bridge arm uniformity. The two solutions are independent of each other, can be implemented individually, and can be combined for application, specifically addressing the core problem of non-uniform imaging in uncooled MEMS infrared sensors: I. An innovative oxygen plasma pretreatment process is added before the bridge arm (BRG) lithography process. Oxygen plasma generated by a plasma resist remover is used to modify the surface of the underlying dielectric material. By adjusting key parameters of the plasma treatment (process temperature, processing time, RF power, and gas flow rate), the surface characteristics of the dielectric are optimized—forming a nanoscale uneven structure to increase the contact area, generating oxygen-containing polar groups to increase surface energy, and promoting the formation of high-energy Si-O bonds. This improves the chemical stability and consistency of the dielectric surface, while suppressing the standing wave effect of deep ultraviolet light. Ultimately, this significantly improves the stability of the bridge arm lithography process, ensuring the uniformity of critical dimensions (CD) and profiles between different bridge arms within the same chip and wafer.

[0041] II. Optimization of the selection method for optimal lithography conditions. Addressing the limitation of traditional techniques where a single exposure shot only monitors the center point and cannot cover the entire field of view, this method improves upon the previous approach by simultaneously monitoring five feature points (upper left, upper right, lower left, lower right, and center) for each exposure shot. Based on the focus energy matrix (FEM), the system filters different combinations of exposure energy and focus values, prioritizing the consistency of bridge arm CD and morphology at the five points. Ultimately, the optimal lithography conditions covering the entire field of view are determined, significantly improving the uniformity of the bridge arm structure 4 within a single exposure shot.

[0042] Neither of the two solutions requires upgrading the lithography equipment or improving the precision of the photomask, effectively controlling production costs, improving process feasibility, and achieving stable voltage output after thermoelectric signal conversion. This results in uniform brightness and clear details in the infrared sensor imaging, significantly improving core imaging performance and successfully solving the core pain point of uneven imaging in existing technologies.

[0043] It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of this invention.

Claims

1. A method for improving the imaging uniformity of an infrared sensor, characterized in that, Includes the following steps: S1. A polyimide layer is formed on the readout circuit wafer and then cured; S2. Etch bridge channels in the polyimide layer until the electrode surface of the readout circuit wafer is exposed; S3. A first dielectric layer is formed on the surface of the readout circuit wafer; S4. A thermistor portion is formed on the first dielectric layer; S5. Remove the first dielectric layer on the surface of the electrode to expose the electrode; S6. A first metal layer is formed on the surface of the readout circuit wafer; S7. A second dielectric layer is formed on the surface of the readout circuit wafer; S8. Perform oxygen plasma treatment on the surface of the second dielectric layer. The treatment conditions include: process temperature 150-200℃, treatment time 1-10min. S9. The second dielectric layer, the first metal layer, and the first dielectric layer are patterned to form a bridge arm structure.

2. The method according to claim 1, characterized in that, In step S8, the oxygen plasma treatment is carried out using a plasma desmearing machine; the treatment conditions also include: radio frequency power of 500-1500W and gas flow rate of 10-30sccm.

3. The method according to claim 1, characterized in that, In step S8, the oxygen plasma treatment process temperature is 180°C and the treatment time is 6 minutes.

4. The method according to claim 1, characterized in that, In step S9, the bridge arm structure formed is an S-shaped bending structure with a line width of 0.2-0.5μm.

5. The method according to claim 1, characterized in that, The first dielectric layer and the second dielectric layer are either silicon nitride or silicon oxide; both the first dielectric layer and the second dielectric layer are deposited by PECVD process.

6. The method according to claim 1, characterized in that, The first metal layer is any one of titanium, titanium nitride, and aluminum; the thermistor film layer is vanadium oxide or amorphous silicon; both the first metal layer and the thermistor film layer are deposited by sputtering process.

7. The method according to claim 1, characterized in that, In step S2, photoresist is coated on the polyimide layer, and after exposure and development, the bridge pier channel is formed by dry etching.

8. The method according to claim 1, characterized in that, In step S4, a thermistor film layer is deposited on the first dielectric layer, and the thermistor portion with a preset pattern is formed by etching.

9. The method according to claim 1, characterized in that, In step S9, the lithography process of the patterning process uses a focusing energy matrix to screen the optimal exposure conditions. Specifically, it includes: defining monitoring points within each exposure field of view, with the center of the field of view as the origin (0,0) and the side length of the field of view as L, and setting the coordinates of the five monitoring points as the upper left (-L / 4, +L / 4), upper right (+L / 4, +L / 4), lower left (-L / 4, -L / 4), lower right (+L / 4, -L / 4), and center (0,0); detecting the linewidth and morphology parameters of the bridge arm at each monitoring point; and selecting the focusing value and exposure energy corresponding to when the linewidth deviation and morphology parameters of all monitoring points meet the requirements as the final lithography conditions.

10. An infrared sensor, characterized in that, It is prepared by the method for improving the imaging uniformity of infrared sensors according to any one of claims 1-9.

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