A method for manufacturing a micro-polarizer array

Abstract

The application discloses a kind of micro polarizer array manufacturing method, mask, substrate and object table, comprising the following steps: by object table, mask and the position mark of exposure substrate alignment;Interrupt exposure beam, relative to exposure field, mask and substrate are synchronously horizontally rotated, so that exposure pattern is on the surface of substrate with expected angle;Mask is exposed, and the grating pattern in the direction specified by specified area patterning of substrate is processed, and exposure beam is interrupted;Substrate is developed, and micro polarizer array is obtained;The application is aligned by object table, mask and the position mark of substrate, one-dimensional grating pattern in the direction specified by specified area patterning of substrate, exposure processing area is combined with mask precision control laser interference lithography technology, can solve the problem that traditional mode processes micro polarizer array with high cost and low efficiency, and can realize the processing of micro polarizer in large scale and large quantities.

Description

Technical Field

[0001] This invention relates to the field of micro polarizer arrays, and in particular to a method for fabricating a micro polarizer array, a mask, a substrate, and a stage. Background Technology

[0002] By acquiring light vector information, polarization imaging can obtain more information about shadows and surface morphology compared to ordinary optical imaging, making it highly favored in military target identification and industrial defect detection. In various polarization imaging camera designs, sensor structures that couple micro-polarizer arrays with photosensitive pixel arrays offer advantages such as real-time acquisition and structural integration.

[0003] Structurally, the micro-polarizer array has an array pattern, with its periodic structure consisting of 2×2 rectangular units. Each unit has a one-dimensional grating pattern that is identical in all four quadrants except for orientation. Since the one-dimensional grating structure has polarization filtering capabilities, in an integrated sensor, the four-quadrant pattern of the micro-polarizer array can provide linearly polarized light in a specific direction to its respective integrated and aligned photosensitive pixel units. In the final image captured by the camera, each 2×2 pixel unit records the polarized light information in all four directions.

[0004] The polarization information of an object includes images obtained after polarization analysis in different directions. Traditional polarization imaging techniques change the direction of collected polarized light by rotating a polarizer in front of the sensor, requiring multiple frames of pattern acquisition to obtain multi-polarization direction information. This is not conducive to real-time measurement and is difficult to capture dynamic scenes. However, integrated sensors based on micro-polarizer arrays can directly obtain multi-directional polarized light information with equal resolution in a single frame of instantaneous image acquisition, facilitating real-time, dynamic polarization information acquisition and analysis in various application scenarios. Due to its rapid acquisition and instantaneous imaging characteristics, micro-polarizer arrays are widely used in various cameras and in special monitoring applications such as military and environmental surveillance.

[0005] Currently, electron beam lithography is the mainstream technology for fabricating micro-polarizer arrays. Electron beam lithography is an ultra-precision micro / nano fabrication technology capable of accurately fabricating microstructures of arbitrary shapes with feature sizes up to the nanometer scale. However, as a direct-write process, it suffers from inefficiency, slow speed, and relatively high cost. Therefore, finding a micro-polarizer array fabrication method that balances high efficiency and low cost is of engineering significance. Summary of the Invention

[0006] The purpose of this invention is to solve the problem of how to fabricate micro polarizer arrays with high efficiency and low cost. It proposes a method for fabricating micro polarizer arrays, a mask, a substrate, and a stage.

[0007] The present invention solves the problem through the following technical solution:

[0008] A method for fabricating a micro polarizer array includes the following steps:

[0009] S1. Align the mask with the position marks on the substrate to be exposed using the stage;

[0010] S2. Interrupt the exposure beam and rotate the mask and the substrate horizontally relative to the exposure field so that the exposure pattern is at the desired angle on the upper surface of the substrate.

[0011] S3. Expose the mask, pattern a grating pattern in a specified direction in a specified area of ​​the substrate, and interrupt the exposure beam;

[0012] S4. The substrate is developed to obtain a micro polarizer array;

[0013] In some embodiments, the alignment of the position marks in step S1 includes the alignment of the Nth quadrant pattern of the mask primary marking unit with the Nth quadrant pattern of the substrate primary marking unit, wherein the Nth quadrant includes: the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant.

[0014] In some embodiments, during the alignment of the Nth quadrant pattern of the mask primary marking unit and the Nth quadrant pattern of the substrate primary marking unit, the Nth quadrant is ordered as the second quadrant, the first quadrant, the fourth quadrant, and the third quadrant.

[0015] The present invention also provides a mask for implementing the above method, the mask comprising a bare die level pattern unit and a mask level marking unit.

[0016] In some embodiments, the die-level patterning unit includes a secondary alignment mark processing area and an array processing area;

[0017] The secondary alignment mark processing area is used to process secondary alignment marks on the substrate during the exposure process. The secondary alignment marks are used for the integrated alignment of the micro polarizer product and the photosensitive device.

[0018] The array processing area is used to process a micro polarizer array on the substrate during the exposure process. The array processing area is a two-dimensional array pattern formed by periodically arranging square windows.

[0019] In some embodiments, the array processing area includes a two-dimensional array periodic unit;

[0020] The two-dimensional array periodic unit includes opaque units and transparent units, and the two-dimensional array periodic unit includes four equally sized square units with equal spacing.

[0021] Of the four square units, one is a light-transmitting unit and three are opaque units, with the spaces between the square units being opaque areas.

[0022] In the array processing area pattern, there is an opaque unit between each light-transmitting unit.

[0023] In some embodiments, the mask primary marking unit includes four alignment units consisting of opaque areas, the alignment units being distributed according to four quadrants;

[0024] The mask primary marking unit is used for alignment with the substrate primary marking unit before exposure, and can control the exposed area of ​​the photoresist in the substrate.

[0025] In some embodiments, the alignment unit is a cross-shaped branch pattern.

[0026] The present invention also provides a substrate for implementing the above method, the substrate comprising: a substrate primary marking unit and an exposed area;

[0027] The substrate primary marking unit needs to be etched in advance before use, and the substrate primary marking unit is used to align with the mask primary marking unit.

[0028] The exposed area includes a substrate secondary alignment mark and a micro polarizer array; the exposed area corresponds to the array processing area, and the micro polarizer array will be exposed and processed in the exposed area.

[0029] In some embodiments, the substrate secondary alignment marks are exposed via the secondary alignment mark processing area during exposure, and are used for the integrated alignment of the micro polarizer array product and the photosensitive device.

[0030] In some embodiments, the micro-polarizer array has a two-dimensional periodic array pattern, and the periodic unit of the micro-polarizer array includes four second square units distributed in four quadrants, with one-dimensional grating patterns that are completely identical except for orientation in the four quadrants.

[0031] In some embodiments, the orientation of the one-dimensional grating pattern in the second quadrant of the micro-polarizer array is 0°, the orientation of the one-dimensional grating pattern in the first quadrant is 45°, the orientation of the one-dimensional grating pattern in the third quadrant is 90°, and the orientation of the one-dimensional grating pattern in the fourth quadrant is 135°.

[0032] In some embodiments, the substrate secondary alignment marks comprise four equal square array patterns, and the substrate secondary alignment marks are distributed according to quadrants.

[0033] The present invention also provides a stage for implementing the above method, the stage comprising: a horizontal rotary table, a three-axis displacement stage, an optical platform, a suspended horizontal support device, and a load;

[0034] The load includes the aforementioned substrate and the aforementioned mask.

[0035] The horizontal rotary table is fixed to the optical platform, and the three-axis displacement stage and the suspended horizontal support device are fixed on the upper surface of the horizontal rotary table.

[0036] The load of the triaxial displacement stage is the substrate;

[0037] The load of the suspended horizontal support device is the mask plate;

[0038] The stage is capable of synchronous horizontal rotation relative to the exposure field, and can also achieve relative triaxial displacement between the substrate and the mask.

[0039] The beneficial effects of this invention compared to the prior art include:

[0040] This invention aligns the mask with the substrate position mark using a stage, patterns a one-dimensional grating pattern in a specified direction in a designated area of ​​the substrate, and combines the mask with precise control of the exposure processing area using laser interference lithography. This solves the problems of high cost and low efficiency in the traditional method of processing micro polarizer arrays, thereby enabling the large-scale, mass production of micro polarizers.

[0041] Other beneficial effects of the embodiments of the present invention will be further described below. Attached Figure Description

[0042] Figure 1 This is a flowchart of a method for fabricating a micro-polarizer array according to an embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of the micro-polarizer array processing system in an embodiment of the present invention;

[0044] Figure 3a This is a schematic diagram of the mask in an embodiment of the present invention;

[0045] Figure 3b This is a schematic diagram of a bare die-level pattern unit in an embodiment of the present invention;

[0046] Figure 3c This is the intention of the two-dimensional array periodic unit in the embodiment of the present invention;

[0047] Figure 3d This is a schematic diagram of the mask primary marking unit in an embodiment of the present invention;

[0048] Figure 4a This is a schematic diagram of the substrate in an embodiment of the present invention;

[0049] Figure 4b This is a schematic diagram of the exposed area in an embodiment of the present invention;

[0050] Figure 4cThis is a schematic diagram of a periodic unit in an embodiment of the present invention;

[0051] Figure 4d This is a schematic diagram of the primary marking unit of the substrate in an embodiment of the present invention;

[0052] Figure 5a This is a schematic diagram showing the alignment of the mask primary marking unit and the substrate primary marking unit in the second quadrant in an embodiment of the present invention;

[0053] Figure 5b This is a schematic diagram showing the alignment of the mask primary marking unit and the substrate primary marking unit in the first quadrant of an embodiment of the present invention;

[0054] Figure 5c This is a schematic diagram showing the alignment of the mask primary marking unit and the substrate primary marking unit in the fourth quadrant in an embodiment of the present invention;

[0055] Figure 5d This is a schematic diagram showing the alignment of the mask primary marking unit and the substrate primary marking unit in the third quadrant in an embodiment of the present invention;

[0056] Figure 6 This is a schematic diagram of the micro-polarizer array processing flow in an embodiment of the present invention;

[0057] The attached figures are labeled as follows:

[0058] 1-Stage, 11-Horizontal Rotary Stage, 12-Three-Axis Translation Stage, 13-Suspended Horizontal Support Device, 2-Substrate, 21-Substrate Primary Marking Unit, 211-Etched Area, 212-Substrate Horizontal Surface, 22-Exposed Area, 221-Substrate Secondary Alignment Mark, 222-Micro Polarizer Array, 2221-Periodic Unit, 22211-First Quadrant Grating, 22212-Second Quadrant Grating, 22213- Third quadrant grating, 22214-Fourth quadrant grating, 3-Mask, 31-Mask primary marking unit, 311-Transparent area, 312-Opaque area, 32-Die-level pattern unit, 321-Secondary alignment marking processing area, 322-Array processing area, 3221-Two-dimensional array periodic unit, 32211-Transparent unit, 32212-Opaque unit, 41-Coherent double beam 1, 42-Coherent double beam 2. Detailed Implementation

[0059] The present invention will be further described below with reference to the accompanying drawings and preferred embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0060] It should be noted that the directional terms such as left, right, up, down, top, and bottom used in this embodiment are only relative concepts or are based on the normal use of the product, and should not be considered as restrictive.

[0061] This invention proposes a method for patterning micro-polarizer arrays: A mask is introduced into a two-beam interference lithography system for precise control of the exposure area. The micro-polarizer array is patterned using four independent steps: "position alignment - horizontal rotation - exposure." Position alignment refers to the alignment of the mask with the substrate's position marks, used to precisely control the exposed area of ​​the photoresist in this exposure step. Horizontal rotation refers to the synchronous horizontal rotation of the mask and substrate relative to the exposure field, used to change the orientation of the exposure pattern on the photoresist in this exposure step. The exposure process is used to pattern a one-dimensional grating pattern with a specified orientation in a designated area of ​​the photoresist. In this invention, the four different orientations of the one-dimensional grating patterns included in the micro-polarizer array structure can be patterned at low cost.

[0062] An overview of the embodiments of the present invention is as follows:

[0063] like Figure 1 As shown, this embodiment of the invention provides a method for fabricating a micro polarizer array, including the following steps:

[0064] S1. Align the mask 3 with the position mark of the substrate 2 to be exposed using the stage 1;

[0065] Specifically, the alignment of the position marks includes the alignment of the Nth quadrant pattern of the mask primary marking unit 31 with the Nth quadrant pattern of the substrate primary marking unit 21, wherein the Nth quadrant includes: the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant.

[0066] Preferably, in the alignment of the Nth quadrant pattern of the primary marking unit 31 of the mask with the Nth quadrant pattern of the primary marking unit 21 of the substrate, the Nth quadrant is ordered as the second quadrant, the first quadrant, the fourth quadrant, and the third quadrant.

[0067] S2. Interrupt the exposure beam and rotate the mask 3 and substrate 2 horizontally relative to the exposure field so that the exposure pattern is at the desired angle on the upper surface of the substrate.

[0068] The exposure pattern refers to a one-dimensional grating with four different orientations formed in the four quadrants of a unit. Each exposure forms a one-dimensional grating structure with a specific orientation. The four quadrants form a unit, and numerous units together form a micro-polarizer array.

[0069] S3. Expose the mask 3, pattern a grating pattern in a specified direction in a specified area of ​​the substrate 2, and interrupt the exposure beam.

[0070] S4. Perform a development operation on the substrate to obtain a micro polarizer array;

[0071] This invention also provides a mask 3 for implementing a method for fabricating a micro polarizer array. The mask includes a bare die-level pattern unit 32 and a mask-level marking unit 31.

[0072] Specifically, the bare die-level patterning unit 32 includes a secondary alignment mark processing area 321 and an array processing area 322;

[0073] The secondary alignment mark processing area 321 is used to process the substrate secondary alignment mark 221 on the substrate 2 during the exposure process. The substrate secondary alignment mark 221 is used for the integrated alignment of the micro polarizer product and the photosensitive device.

[0074] The array processing area 322 is used to process a micro polarizer array 222 on the substrate 2 during the exposure process. The array processing area 322 is a two-dimensional array pattern formed by periodically arranging square windows.

[0075] Furthermore, the array processing area 322 includes two-dimensional array periodic units 3221;

[0076] The two-dimensional array periodic unit 3221 includes an opaque unit 32212 and a transparent unit 32211. The two-dimensional array periodic unit 3221 includes four equally sized square units with equal spacing.

[0077] Of the four square units, one is a light-transmitting unit 32211, and three are opaque units 32212. The area between the square units is opaque.

[0078] In the array processing area 322 pattern, there is an opaque unit 32212 between each light-transmitting unit 32211.

[0079] Specifically, the mask primary marking unit 31 includes four alignment units consisting of opaque areas, and the alignment units are distributed according to the four quadrants;

[0080] The mask primary marking unit 31 is used to align with the substrate primary marking unit 21 before exposure, and can control the exposed area 22 of the photoresist in the substrate 2.

[0081] Preferably, the alignment unit is a cross-shaped branch pattern.

[0082] This invention also provides a substrate 2 for implementing a micro polarizer array fabrication method. The substrate 2 includes: a substrate primary marking unit 21 and an exposed area 22.

[0083] The substrate primary marking unit 21 needs to be etched in advance before use. The substrate primary marking unit 21 is used to align with the mask primary marking unit 31.

[0084] The exposed area 22 includes a substrate secondary alignment mark 221 and a micro polarizer array 222; the exposed area 22 corresponds to the array processing area 32, and the micro polarizer array 222 will be exposed and processed in the exposed area 22.

[0085] Specifically, the secondary alignment mark 221 on the substrate is exposed via the secondary alignment mark processing area 321 during exposure and is used for the integrated alignment of the micro polarizer array product and the photosensitive device.

[0086] Specifically, the micro-polarizer array 222 has a two-dimensional periodic array pattern. The periodic unit 2221 of the micro-polarizer array 222 includes four second square units distributed in four quadrants, and the four quadrants have a one-dimensional grating pattern that is completely consistent except for the orientation.

[0087] Furthermore, the one-dimensional grating pattern direction in the second quadrant of the micro polarizer array 222 is 0°, the one-dimensional grating pattern direction in the first quadrant is 45°, the one-dimensional grating pattern direction in the third quadrant is 90°, and the one-dimensional grating pattern direction in the fourth quadrant is 135°.

[0088] Specifically, the substrate secondary alignment mark 221 includes four equal square array patterns, and the substrate secondary alignment mark 221 is distributed according to quadrants.

[0089] The present invention also provides a stage 1 for realizing a method for fabricating a micro polarizer array. The stage 1 includes: a horizontal rotary stage 11, a three-axis displacement stage 12, an optical platform, a suspended horizontal support device 13, and a load.

[0090] The load includes the aforementioned substrate 2 and the aforementioned mask 3;

[0091] A horizontal rotary table 11 is fixed on an optical platform. A three-axis displacement stage 12 and a suspended horizontal support device 13 are fixed on the upper surface of the horizontal rotary table 11.

[0092] The load of the three-axis displacement stage 12 is the substrate;

[0093] The load of the suspended horizontal support device 13 is a mask.

[0094] The stage 1 can achieve synchronous horizontal rotation relative to the exposure field, and can also achieve relative triaxial displacement between the substrate 2 and the mask 3.

[0095] In this embodiment of the invention, the optical platform is used to fix a horizontal rotary table. It is a stable platform with square-arranged engineering threaded holes for fixing optical elements.

[0096] Two-beam interference lithography is a highly efficient and low-cost one-dimensional grating patterning process. Since the periodic units of a four-quadrant micro polarizer array also contain one-dimensional gratings, it is feasible to improve this lithography process and develop a new process for micro polarizer array fabrication.

[0097] The purpose of this invention, specifically for micro-polarizer arrays, is to provide a low-cost, rapid fabrication process and system.

[0098] Example:

[0099] The micro-polarizer array fabrication system in this embodiment of the invention is as follows: Figure 2 As shown, from top to bottom, it includes two parts: the dual-beam exposure optical path and the stage 1.

[0100] It also includes a mask 3, an exposed substrate 2, and a stage 1. The mask 3 is used to precisely control the exposed area. Photoresist is spin-coated on the substrate 2, and a corresponding photoresist pattern is formed through the exposure effect of the dual-beam exposure optical path. In this embodiment of the invention, a micro-polarizer array pattern is mainly formed on it. The stage 1 includes a three-axis displacement stage 12 and a horizontal rotation stage 11. The former controls the relative movement between the mask 3 and the substrate 2, and the latter is used to rotate the whole composed of the mask 3 and the substrate 2 to change the direction of the generated one-dimensional grating pattern. The coherent dual beams 41 / 42 are used to form an alternating bright and dark exposure field, which is recorded by the photoresist on the surface of the substrate 2 and finally washed away by the developer to form the desired pattern. The coherent dual beams 41 / 42 include coherent dual beam 141 and coherent dual beam 242.

[0101] The three-axis displacement stage 12 can simplify the structure by not providing displacement in the z-direction, and only include two axial displacements in the x and y directions. In this case, the suspended horizontal support device 13 needs to be replaced with a telescopic support device in order to adjust the relative distance between the mask 3 and the substrate 2.

[0102] Dual-beam exposure is a mature interference lithography process used for one-dimensional grating patterning. Figure 2 The image only shows the two coherent exposure beams 41 / 42 at the end of the optical path, their overlapping exposure fields, and the horizontal plane where the coherent beams of the exposure fields overlap.

[0103] The stage 1 is composed of a horizontal rotary stage 11 and a three-axis displacement stage 12, and its load includes a substrate 2 and a mask 3.

[0104] A horizontal rotary stage 11, represented by a wide cylinder, is fixed to an optical platform. A three-axis displacement stage 12 and a suspended horizontal support device 13 are fixed to its upper surface. The three-axis displacement stage 12, represented by a cube, bears the load of the substrate 2 to be exposed. The suspended horizontal support device 13, represented by a double-long cylinder, bears the load of the mask 3.

[0105] The stage 1 can provide synchronous horizontal rotation of the substrate 2 and the mask 3 relative to the exposure field, and can also provide relative triaxial displacement between the substrate 2 and the mask 3.

[0106] The macroscopic and detailed design of the mask 3 pattern in the micro polarizer array processing system of this invention is as follows: Figures 3a-3d As shown.

[0107] like Figure 3a As shown, the mask pattern design in this embodiment of the invention includes multiple die-level pattern units (bare die-level pattern units) 32 with identical centers and multiple (spare) mask-level marking units 31 with identical outer sides. A schematic diagram of a single bare die-level pattern unit 32 is shown below. Figure 3b As shown, a schematic diagram of the two-dimensional array periodic element 3221 is as follows. Figure 3c As shown.

[0108] In this embodiment of the invention, a single die-level patterning unit 32 includes an outer secondary alignment mark processing area 321 and a central array processing area 322.

[0109] Die refers to the unpackaged chip, which is a small piece cut from a silicon wafer using a laser. Each die is an independent functional unit, and after being packaged, it can be used directly as a chip.

[0110] The secondary alignment mark processing area 321 is used to process the substrate secondary alignment mark 221 on the substrate 2 during the exposure process. The latter will be used for the integrated alignment of the micro polarizer product and the photosensitive device.

[0111] The array processing area 322 is used to process a bare-die-level micro-polarizer array 222 on the substrate 2 during the exposure process. Its pattern is a two-dimensional array pattern formed by periodically arranged square windows. In the enlarged view, the opaque area, the same size as the square windows, is drawn with dashed lines. In the pattern design of the processing area, the two-dimensional array periodic unit 3221 can be considered as a rectangle containing four equally sized, equally spaced square units. Of the four units, one is a transparent unit 32211, and three are opaque units 32212. The spacing between the units is filled by the opaque area. The parameters and number of the two-dimensional array periodic units in the micro-polarizer array processing area 322 can be determined according to requirements.

[0112] Figure 3d This is a schematic diagram of the primary marking unit 31 of the mask, which includes four equal cross-shaped patterns composed of opaque areas, distributed according to quadrants. The pattern of the primary marking unit 31 of the mask is used to align with the position of the primary marking unit 21 of the substrate before exposure, thereby indirectly controlling the exposed area of ​​the photoresist on the substrate 2.

[0113] Macro and detail design of the pattern on the exposed substrate 2 in the processing system, such as Figures 4a-4d As shown.

[0114] Figure 4a This is a macroscopic schematic diagram of the initial pattern of the substrate 2 to be exposed. In the initial case, before entering the micro polarizer array processing system, multiple identical (spare) substrate primary marking units 21 need to be etched on the outer side of the substrate 2 to be exposed in advance, for alignment with the mask primary marking units 31 in subsequent processing. Figure 4a Meanwhile, a bare-die level exposure area 22 is schematically marked in the center of the exposed substrate 2, corresponding to the bare-die level pattern unit 32 of the mask, and the micro polarizer array 222 will be exposed and processed in this area.

[0115] Figure 4b This diagram illustrates the pattern of a single die-level exposed area 22 on substrate 2 after the micro polarizer array patterning process is completed.

[0116] Figure 4c This is a partial enlarged view of the central micro polarizer array 222 pattern. At this time, the substrate die-level unit pattern exposure area 22 includes the outer "substrate secondary alignment mark 221" and the central "micro polarizer array 222".

[0117] The substrate secondary alignment mark 221 is exposed through the secondary alignment mark processing area 321 of the mask 3 during exposure, and is used for the integration and alignment of micro polarizer array products and photosensitive devices in practical applications.

[0118] The micro-polarizer array 222 has a two-dimensional periodic array pattern. Its periodic unit 2221 can be considered as a rectangular structure containing four square units distributed in four quadrants. The four quadrants have a one-dimensional grating pattern that is completely consistent except for the orientation.

[0119] For now, we define the direction of the one-dimensional grating in the second quadrant as 0, such as... Figure 4c As shown, the first quadrant grating 22211 has an orientation of 45°, the second quadrant grating 22212 has an orientation of 0°, the third quadrant grating 22213 has an orientation of 90°, and the fourth quadrant grating 22214 has an orientation of 135°.

[0120] Figure 4d This is a schematic diagram of a single substrate primary marking unit 21 pattern, including four equal square array patterns composed of etched areas 211 and substrate horizontal planes 212, distributed in quadrants, with symmetrical but slightly offset positions.

[0121] In this embodiment of the invention, the substrate primary marking unit 21 and the mask primary quasi-marking unit 31 are matched in size and position, and have four alignment methods. Both alignment marks can only be aligned in a single quadrant at a time. Figures 5a-5dThis demonstrates the alignment in each of the four quadrants. Figure 5a Alignment for the second quadrant; Figure 5b Alignment for the first quadrant; Figure 5c Alignment for the fourth quadrant; Figure 5d Alignment is performed in the third quadrant. The dark color represents the opaque area 312 of the primary mask marking unit 31, the light color represents the etched area 211 of the substrate marking, and the white color represents the horizontal surface 212 of the substrate.

[0122] The four alignment conditions can be transformed into one another by the relative displacement of the mask 3 and the substrate 2. This relative displacement can be adjusted by the triaxial stage 12, and whether the alignment is correct needs to be observed with a microscope. Under the four alignment conditions, the light-transmitting pattern of the mask die-level pattern unit 32 will generate different exposed areas 22 on the substrate 2. In fact, the exposed areas 22 will correspond to the four quadrants of the periodic units 2221 in the micro polarizer array 222 to be processed. Specific implementation examples:

[0124] Figure 6 This paper demonstrates the basic workflow of multi-step exposure processing for micropolarizer arrays. The workflow consists of four processing steps, each of which completes the processing of a one-dimensional grating within a specific quadrant of the micropolarizer array unit. Each processing step includes three sub-steps: position mark alignment, horizontal rotation, and exposure.

[0125] The specific embodiments are summarized below:

[0126] Position markers aligned, such as Figure 6 As shown in the first column on the left: Under microscope observation, the exposed substrate is adjusted by a three-axis displacement stage to complete the alignment of the second quadrant pattern of the mask alignment mark with the second quadrant pattern of the substrate alignment mark, and the three-axis displacement stage is fixed.

[0127] Rotate horizontally, such as Figure 6 As shown in the middle column: the exposure beam is interrupted by the shutter, a composite displacement stage is fixed in the corresponding area of ​​the exposure field, and the substrate and the mask are rotated horizontally synchronously so that the exposure pattern (fixed in position in the exposure system) is at the expected angle on the upper surface of the substrate, and the horizontal rotation stage is fixed.

[0128] Exposure, such as Figure 6 As shown in the first column on the right, open the shutter to expose the mask with the desired amount of light, then close the shutter to complete the exposure for that quadrant.

[0129] The processing steps and logic for the subsequent three quadrants are the same as those for the second quadrant. After exposure processing is completed in all four quadrants, the substrate to be exposed is removed from the three-axis displacement stage and developed to obtain a lithography thin-film micro-polarizer array with actual contours.

[0130] The fabrication process of the four-quadrant micro-polarizer array is as follows:

[0131] Taking the sequential processing order of the micro-polarizer array in quadrants two, one, four, and three as an example,

[0132] 1. Place the mask in front of the substrate to be exposed, align the mask with the substrate by matching the alignment marks in the second quadrant, and perform interference exposure on the second quadrant region in the initial 0° direction to form a grating in the 0° direction.

[0133] 2. Move the substrate to be exposed so that the square light-transmitting window of the mask corresponds to the first quadrant. Align the mask with the substrate by matching the alignment marks of the first quadrant, and rotate the mask and the substrate together to 45° (relative to the initial position) to perform interference exposure on the first quadrant area to form a grating in the 45° direction.

[0134] 3. Move the substrate to be exposed so that the square light-transmitting window of the mask corresponds to the fourth quadrant. Align the mask and the substrate by matching the alignment marks of the fourth quadrant, and rotate the mask and the substrate together to 90° to perform interference exposure on the fourth quadrant area to form a grating in the 90° direction.

[0135] 4. Move the substrate to be exposed so that the square light-transmitting window of the mask corresponds to the third quadrant. Align the mask with the substrate by matching the alignment marks of the third quadrant, and rotate the mask and the substrate together to 135° to perform interference exposure on the third quadrant area to form a grating in the 135° direction.

[0136] These four steps allow for the formation of a complete micro-polarizer array photoresist pattern on the exposed substrate.

[0137] Figure 6 The first row shows the processing of the second quadrant of the micro-polarizer array unit; the second, third, and fourth rows show the processing of the first, fourth, and third quadrants of the micro-polarizer array unit, respectively.

[0138] The second-quadrant mask and substrate position marks are microscopically aligned. The mask and substrate are then mounted into the optical path, and the horizontal angle is adjusted by rotation. The second-quadrant one-dimensional grating is then exposed. The first-quadrant mask and substrate position marks are microscopically aligned. The mask and substrate are then mounted into the optical path, and the horizontal angle is adjusted by rotation. The first-quadrant one-dimensional grating is then exposed.

[0139] The fourth quadrant mask and substrate position marks are microscopically aligned. The mask and substrate are then installed into the optical path, and the horizontal angle is adjusted by rotation. The fourth quadrant one-dimensional grating is then exposed. Similarly, the third quadrant mask and substrate position marks are microscopically aligned. The mask and substrate are then installed into the optical path, and the horizontal angle is adjusted by rotation. The third quadrant one-dimensional grating is then exposed.

[0140] Comparative example:

[0141] The existing mainstream processing technologies are electron beam lithography, nanoimprint lithography, and ion beam etching.

[0142] Electron beam lithography uses an electron beam to irradiate the surface of a photoresist, exposing it according to a pre-defined pattern. It can achieve resolutions below 5nm, but it is costly and time-consuming, making it unsuitable for large-area processing; it is generally used for creating photomasks. Nanoimprint lithography pre-fabricates a nanopattern on the surface of a photomask, then controls the mask's temperature and pressure to transfer the pattern onto the surface polymer. Its resolution can also reach below 5nm, enabling mass production. However, its drawbacks are also significant: the cost of fabricating molds for other patterns is high. Focused ion beam etching uses a focused ion beam to directly etch the sample surface. It can process complex three-dimensional structures, achieving a resolution of 10nm. However, it shares the same drawbacks as electron beam lithography.

[0143] While the first three technologies all offer high resolution, they also suffer from high cost and long processing times. Laser interferometry lithography, on the other hand, is well-suited for fabricating these periodic micro / nano structures, offering advantages in both efficiency and low cost.

[0144] This invention combines precise mask control with laser interference lithography technology to control the exposure processing area, achieving high-efficiency and low-cost micro-polarizer array processing. It enables large-scale, mass production of micro-polarizers.

[0145] The micro-polarizer prepared according to the embodiments of this invention can be applied to the field of polarization imaging and detection technology, forming a focal plane imaging and detection system with a detector to achieve simultaneous detection of polarization information in multiple polarization directions. Currently, there are no mature micro-polarizer products on the market prepared using the method provided in the embodiments of this invention. The embodiments of this invention can provide a solution for achieving rapid and low-cost fabrication of such products.

[0146] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several equivalent substitutions or obvious modifications can be made without departing from the concept of the present invention, and all such modifications, achieving the same performance or purpose, should be considered within the scope of protection of the present invention.

Claims

1. A method for fabricating a micro-polarizer array, characterized in that, Includes the following steps: S1. Align the mask with the position marks on the substrate to be exposed using the stage; The alignment of the position marks includes the alignment of the Nth quadrant pattern of the mask primary marking unit with the Nth quadrant pattern of the substrate primary marking unit, wherein the Nth quadrant includes: the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant; the substrate primary marking unit needs to be etched in advance before use, and the substrate primary marking unit is used for position alignment with the mask primary marking unit. S2. Interrupt the exposure beam and rotate the mask and the substrate horizontally relative to the exposure field so that the exposure pattern is at the desired angle on the upper surface of the substrate. S3. Expose the mask, pattern a one-dimensional grating pattern with a predetermined direction in a designated area of ​​the substrate, and interrupt the exposure beam after exposure is completed; S4. The substrate is developed to obtain a micro polarizer array; S1, S2, and S3 sequentially constitute a processing step. The micro-polarizer array fabrication method includes four processing steps, each of which completes the processing of a one-dimensional grating within one quadrant of the micro-polarizer array unit. The periodic unit of the micro-polarizer array includes four square units distributed in four quadrants, with one-dimensional grating patterns that are completely identical except for orientation in the four quadrants. The sequential processing order of the four processing steps is the second quadrant, the first quadrant, the fourth quadrant, and the third quadrant. The stage includes a horizontal rotary stage, a three-axis displacement stage, an optical platform, and a suspended horizontal support device; the horizontal rotary stage is fixed to the optical platform, and the three-axis displacement stage and the suspended horizontal support device are fixed on the upper surface of the horizontal rotary stage; the load of the three-axis displacement stage is the substrate; the load of the suspended horizontal support device is the mask; the stage can realize synchronous horizontal rotation of the mask and the substrate relative to the exposure field, and can also realize relative three-axis displacement between the substrate and the mask.

2. The method for fabricating a micro-polarizer array as described in claim 1, characterized in that, The mask includes bare-chip level pattern units and mask level mark units.

3. The method for fabricating a micro-polarizer array as described in claim 2, characterized in that, The bare die-level patterning unit includes a secondary alignment mark processing area and an array processing area; The secondary alignment mark processing area is used to process secondary alignment marks on the substrate during the exposure process. The secondary alignment marks are used for the integrated alignment of the micro polarizer array product and the photosensitive device. The array processing area is used to process a micro polarizer array on the substrate during the exposure process. The array processing area is a two-dimensional periodic array pattern formed by the periodic arrangement of square windows.

4. The method for fabricating a micro-polarizer array as described in claim 3, characterized in that, The two-dimensional periodic array pattern includes two-dimensional array periodic units; The two-dimensional array periodic unit includes opaque units and transparent units, and the two-dimensional array periodic unit includes four equally sized square units with equal spacing. Of the four square units, one is a light-transmitting unit and three are opaque units, with the spaces between the square units being opaque areas. In the array processing area, there is an opaque unit between each light-transmitting unit.

5. The method for fabricating a micro-polarizer array as described in claim 2, characterized in that, The mask primary marking unit includes four alignment units composed of opaque areas, and the alignment units are distributed according to four quadrants; The mask primary marking unit is used for alignment with the substrate primary marking unit before exposure, and can control the exposed area of ​​the photoresist in the substrate.

6. The method for fabricating a micro-polarizer array as described in claim 5, characterized in that, The alignment unit has a cross-shaped branch pattern.

7. The method for fabricating a micro-polarizer array as described in claim 3, characterized in that, The substrate includes: a primary marking unit and an exposed area; The substrate primary marking unit needs to be etched in advance before use, and the substrate primary marking unit is used to align with the mask primary marking unit. The exposed area includes a substrate secondary alignment mark and a micro polarizer array; the exposed area corresponds to the array processing area, and the micro polarizer array will be exposed and processed in the exposed area.

8. The method for fabricating a micro-polarizer array as described in claim 7, characterized in that, The secondary alignment marks on the substrate are obtained by exposure through the secondary alignment mark processing area during exposure, and are used for the integrated alignment of the micro polarizer array product and the photosensitive device.

9. The method for fabricating a micro-polarizer array as described in claim 1, characterized in that, The one-dimensional grating pattern in the second quadrant of the micro-polarizer array has an orientation of 0°, the one-dimensional grating pattern in the first quadrant has an orientation of 45°, the one-dimensional grating pattern in the third quadrant has an orientation of 90°, and the one-dimensional grating pattern in the fourth quadrant has an orientation of 135°.

10. The method for fabricating a micro-polarizer array as described in claim 7, characterized in that, The substrate secondary alignment marks include four equal square array patterns, and the substrate secondary alignment marks are distributed according to quadrants.

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