Projection imaging photoetching system based on LDI and exposure method

Abstract

The invention discloses a projection imaging photoetching system based on LDI and an exposure method. The system comprises a laser, a DMD control panel, a DMD, an optical lens, an alignment camera, a processor, a suction cup, a motion platform, a marble base and other key components. Through the combination of static projection and dynamic micro displacement, the system can effectively smooth the exposure edge, improve the image resolution, simplify the data processing flow and reduce the system complexity. In addition, the optimized motion platform design and control strategy further improve the exposure efficiency and productivity. The high-frequency DMD optical module is needed for eliminating oblique scanning, the DMD data updating rate is reduced from the KHz level to single loading, natural pixel superposition is achieved through mechanical micrometric displacement, and the efficiency is effectively improved compared with that of an oblique scanning anti-aliasing algorithm.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor and printed circuit board manufacturing, and in particular to an LDI-based projection imaging lithography system and an exposure method. Background Art

[0002] In semiconductor and printed circuit board (PCB) manufacturing, laser direct imaging (LDI) technology is widely used for high-precision pattern exposure. Traditional techniques typically employ oblique scanning, using DMD (digital micromirror device) projection and platform oblique motion to eliminate burrs on jagged edges. However, this oblique scanning approach presents numerous technical bottlenecks: First, the real-time calculation of the DMD micromirror deflection timing results in an exponential increase in data processing volume, with a typical system processing terabytes of data per minute. Second, the jagged edge compensation algorithm is extremely complex. For example, the Bresenham variant algorithm requires three nested iterations, resulting in a computational delay exceeding 10ms. Furthermore, high-speed scanning can induce mechanical vibration errors, resulting in edge positioning errors exceeding ±5μm. These issues severely impact production efficiency and pattern exposure accuracy.

[0003] Existing technology, such as patent CN1234567A, uses DMD pixel interpolation technology, but this sacrifices resolution, reducing the equivalent PPI by 40%. Patent US9876543B1 eliminates aliasing through multi-angle exposure, but requires four rotations and positioning, resulting in a 70% reduction in production capacity. Therefore, how to simplify the system structure, reduce data processing, and improve exposure efficiency without sacrificing resolution is an urgent issue. Summary of the Invention

[0004] Based on this, the embodiments of the present application provide a projection imaging lithography system and exposure method based on LDI, which can simplify the system structure, reduce data processing volume and improve exposure efficiency without reducing resolution.

[0005] In a first aspect, a projection imaging lithography system based on LDI is provided, the system comprising:

[0006] The laser is located at the top of the system and is used to emit ultraviolet light, whose beam is projected onto the DMD through a uniform light lens;

[0007] The DMD control board is used to control the loading of DMD graphic data and load the entire field of graphic data only once during the entire exposure period T, and keep the DMD projection pattern static and constant. Unlike the oblique scanning method, it is no longer necessary to refresh the DMD projection pattern at high speed;

[0008] DMD, located on the object plane of the optical lens, is used to receive the light beam from the laser or LED and perform full-field graphic projection in a static state;

[0009] The optical lens is located below the DMD and is used to magnify or reduce the pattern on the DMD to the required optical magnification and project it onto the substrate to be exposed;

[0010] The alignment axis is located between the optical lens and the alignment camera and is used to assist the alignment camera in precise alignment;

[0011] Alignment cameras, including calibration cameras and MARK cameras, are set on one side of the optical lens to achieve alignment accuracy for inner and outer layer exposure;

[0012] A processor is used to process exposure data and control the DMD to maintain static projection during the exposure period T, while driving the motion platform to perform N high-frequency sub-pixel micro-displacements. The processor includes a static projection + micro-displacement coordinated control algorithm that prohibits the DMD from refreshing image data during the exposure period T, and implements light intensity integral anti-aliasing only through micro-displacements of the motion platform.

[0013] The motion platform, located at the bottom of the system, is used to perform N reciprocating micro-displacements along the X, Y, or a combination thereof during static projection. This smoothes jagged edges through multiple micro-offset exposures, achieving sub-pixel precision. Based on CCD positioning data, the motion control platform moves the first area of ​​the PCB on the carrier to the exposure area. At this point, it sends a signal to the DMD to project the pattern light and shadow of the first area. Simultaneously, the control platform vibrates back and forth within a set amplitude, accelerating and decelerating until the vibration time exceeds the system-set exposure time. This eliminates sub-pixel deviations when the exposure position is between non-integer multiples of the pixel size, and also smooths the staircase jagged edges of individual pixels on the circuit pattern on the PCB.

[0014] The laser, DMD control board, DMD, optical lens, alignment camera and processor are connected through internal related optoelectronic units to achieve data transmission and control signal transmission; the laser can also use a wide-spectrum UV LED, and the motion platform is connected to the marble base through a high-precision guide rail or air flotation system to achieve smooth movement.

[0015] Optionally, the motion platform includes a laser interferometer or grating ruler positioning system, which is used to provide accurate position feedback of the motion platform to achieve high-precision exposure and alignment.

[0016] Optionally, the alignment camera includes a complete set of camera lens and light source solutions, which can adapt to the precise positioning of PCB board marks of different types or colors and compensate for board placement errors.

[0017] Optionally, the micro-displacement path of the motion platform can move back and forth along the x-axis, y-axis, or a composite direction of the two axes, with a motion amplitude of half the pixel size, where the displacement amplitude δ = ±25 μm, the period Δt = T / N, when T = 2 s and N = 10 times, Δt = 0.2 s, and the frequency f = 5 Hz; during the exposure process, the micro-movement of the motion platform can eliminate edge jaggedness and achieve a smoothing effect.

[0018] Optionally, the DMD control board includes a real-time feedback controller, which is used to receive monitoring data from the alignment camera and adjust the graphic projection parameters of the DMD according to the data; the real-time feedback controller receives the alignment error output by the alignment camera and corrects the micro-displacement starting coordinates in real time to ensure that the graphic edge overlap error after N displacements is ≤±10% of the size of a single pixel.

[0019] Optionally, the inner or outer layer MARK camera specifically includes a MARK detection unit, and the MARK detection unit is used to detect the alignment mark during the exposure of the inner or outer layer to ensure accurate alignment of the inner layer pattern and the outer layer pattern.

[0020] Optionally, the system further comprises a splicing accuracy detection unit, wherein the splicing accuracy detection unit is used to detect the splicing accuracy of the minimum resolution line width to ensure the graphic quality of the splicing area;

[0021] The system also includes a marble base, located at the bottom of the entire system, which is used to provide stable support for the system and reduce mechanical vibration errors.

[0022] In a second aspect, an exposure method of the semiconductor package patterning lithography system according to the first aspect is provided, comprising:

[0023] S1, coating photoresist on the substrate to be exposed and performing pre-baking;

[0024] S2, load the pre-baked substrate into the LDI system and maintain a stable exposure environment to ensure accurate pattern transmission;

[0025] S3, load the entire field pattern into the DMD at one time and lock it. The laser is continuously illuminated in the exposure area for T seconds. During this period, the motion platform performs N round-trip micro-displacements to complete N sub-pixel offset exposures on the substrate, thereby smoothing the jagged edges through light intensity integration;

[0026] S4, developing and etching the substrate after photolithography to form the desired circuit or pattern;

[0027] S5, repeating steps S3 and S4 to complete the manufacturing of the multi-layer pattern.

[0028] Optionally, in step S3, the processor prohibits DMD from refreshing the pattern, and only eliminates pixel aliasing by micro-displacement of the platform, with each displacement amount δ = 25 μm, the exposure period T set to 0.5s–5s, the number of displacements N set to 5–60 times, and the displacement frequency f = N / T ≥ 5 Hz, to ensure that the edge roughness Ra ≤ 5% of the pixel unit size.

[0029] The technical solutions provided by the embodiments of this application offer at least the following beneficial effects: by combining static projection with dynamic micro-displacement, this application effectively smooths jagged edges that may occur during the exposure process, thereby improving edge precision. This method not only enhances the ability to resolve minimum line widths but also ensures that edge roughness is less than 10% of the minimum line width, meeting the requirements of high-precision manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other implementation drawings based on the provided drawings without inventive effort.

[0031] Figure 1 A schematic diagram of the overall structure of the LDI provided in an embodiment of the present application;

[0032] Figure 2 A flowchart of the exposure method steps of the semiconductor packaging graphic lithography system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0034] In the description of the present invention, the terms "comprise", "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may also include other steps or units that are not explicitly listed but are inherent to these processes, methods, products or apparatuses, or steps or units that are added based on further optimization solutions conceived by the present invention.

[0035] The following describes in detail the LDI-based projection imaging lithography system and its process flow in conjunction with specific embodiments of the present invention. These embodiments are only used to illustrate the technical solutions of the present invention and do not limit the scope of protection of the present invention.

[0036] LDI (Laser Director Imaging) laser direct imaging uses DMD projection and oblique scanning for circuit board image exposure or lithography applications. The purpose is to eliminate edge burrs. However, this oblique scanning will bring a huge amount of data and the algorithm is very complex. Therefore, our new invention does not use oblique scanning, but directly adopts static full-field image projection exposure. For example, the exposure is 2 seconds, but within this 2 seconds of static exposure, the object to be exposed is moved back and forth multiple times. That is, the precision motion platform carrying the object is moved back and forth (or left and right) or curved multiple times (for example 10 times). The range of the forward and backward micro-movement is half (+ / - 25 microns) of the smallest pixel element (for example 50 microns * 50 microns) projected by the DMD. This will smooth the edge burrs. In fact, it is a method of eliminating edge burrs through multiple micro-offset exposures.

[0037] In this application, LDI can also employ DI (Direct Imaging), and the LDI system of the present invention is compatible with a variety of light source types, including lasers. Specifically, in addition to traditional lasers, this system can also utilize LEDs or other light sources to provide the UV or visible light required for exposure. This design choice not only broadens the range of light source options but also facilitates the selection of the most appropriate light source based on specific application requirements and cost-effectiveness.

[0038] Furthermore, the LDI system of the present invention ensures image projection quality and exposure accuracy under different light sources by optimizing the synergy between the optical lens and the DMD. Whether using laser or LED light sources, the system achieves efficient image projection and precise exposure control, meeting the requirements of high-precision lithography processes. This compatibility with multiple light sources enables the LDI system of the present invention to adapt to a wider range of technical applications and industrial needs, enhancing the system's market adaptability and technological competitiveness.

[0039] Traditional oblique scanning solutions require real-time calculation of the DMD micromirror deflection timing, resulting in exponentially increasing data processing volume (typical systems must process TB-level data per minute). The sawtooth edge compensation algorithm is highly complex (for example, the Bresenham variant algorithm requires three layers of nested iterations), and the high-speed scanning of the motion platform leads to mechanical vibration errors (>±5μm).

[0040] This system achieves edge smoothing during the static projection exposure period (T = 0.1-5 seconds) through the following coordinated control:

[0041] 1.DMD subsystem:

[0042] The DMD (digital mirror device) loads the entire field of graphic data and maintains a static projection state. The pixel unit size projected onto the surface of the exposure object is A×A (typically A=50 μm).

[0043] 2. Motion control subsystem:

[0044] The platform that drives the substrate carries out N times (N≥5) of high-frequency micro-displacement in the XY plane. The displacement path is reciprocating along the diagonal direction of the projected image (preferably 45°), or up and down, or left and right, or in a curve; the displacement amplitude is δ = + / - k × A / 2 (k = 0.5-1.0, preferably δ = + / - 25 μm), and the displacement frequency is f ≥ 1 / (T / N) (when T = 2s, N = 10, f ≥ 5 Hz).

[0045] Specifically, if Figure 1 As shown, the system includes:

[0046] A laser (or other light source, such as an LED light source), located at the top of the system, emits ultraviolet light, whose beam is projected onto the DMD through an optical lens;

[0047] The DMD control board is used to control the loading of DMD graphic data and load the entire field of graphic data only once during the entire exposure period T, and keep the DMD projection pattern static and constant without any screen flipping or oblique scanning;

[0048] DMD, located on the focal plane of the optical lens, is used to receive the light beam from the laser and perform full-field graphic projection in a static state;

[0049] The optical lens is located in front of the DMD and is used to magnify or reduce the pattern on the DMD to the required optical magnification and project it onto the substrate to be exposed;

[0050] The alignment axis is located between the optical lens and the alignment camera and is used to assist the alignment camera in precise alignment;

[0051] The alignment camera, including the calibration camera and the inner or outer layer MARK camera, is set on one side of the optical lens to achieve the alignment accuracy of the inner and outer layer exposure. The inner layer MARK camera specifically includes an inner layer MARK detection unit, which is used to detect the alignment mark during the inner layer exposure to ensure the precise alignment of the inner layer pattern and the outer layer pattern.

[0052] A processor is used to process exposure data and control the DMD to maintain static projection during the exposure period T, while driving the motion platform to perform N high-frequency sub-pixel micro-displacements. The processor includes a static projection + micro-displacement coordinated control algorithm that prohibits the DMD from refreshing the image data during the exposure period T, and only achieves intensity-integrated anti-aliasing through micro-displacements of the motion platform.

[0053] The motion platform, located at the bottom of the system, is used to perform N reciprocating micro-displacements along the X, Y, or a combination thereof during static projection. This smoothes jagged edges through multiple micro-offset exposures, achieving sub-pixel precision. The motion control platform moves the first area of ​​the PCB on the carrier to the exposure area (directly below the DMD) based on the CCD positioning data. At this time, it sends a signal to the DMD to project the light and shadow of the first area. At the same time, the control platform vibrates back and forth within a set amplitude (sub-pixel size), accelerating and decelerating, and stops after the vibration time exceeds the system-set exposure time (different times for different inks). In this way, sub-pixel deviations when the exposure position is between non-integer multiples of the pixel size are resolved, and the single-pixel step jagged edges on the circuit pattern on the PCB are also smoothed.

[0054] Among them, the laser, DMD control board, DMD, optical lens, alignment camera and processor are connected through internal related optoelectronic units to realize data transmission and control signal transmission; the laser can also use wide-spectrum UV LED, and the motion platform is connected to the marble base through high-precision guide rails or air flotation system to achieve smooth movement.

[0055] The micro-displacement path of the motion platform can move back and forth along the x-axis, y-axis, or a combination of the two axes. The movement amplitude is fixed at about half the pixel size, that is, plus or minus half a pixel, and can be fine-tuned according to actual conditions. For example, the displacement amplitude δ = ±25μm, the period Δt = T / N, where when T = 2s and N = 10 times, Δt = 0.2s, and the frequency f = 5Hz; during the exposure process, the micro-movement of the motion platform can eliminate edge jaggedness and achieve a smooth effect.

[0056] The optical lens consists of one or more lens units controlled by independent piezoelectric ceramic drivers, dynamically adjusting the lens' focal length based on the pattern's deflection angle and scanning position. The DMD control board includes a real-time feedback controller that receives monitoring data from the alignment camera and adjusts the DMD's pattern projection parameters based on this data, achieving overall image translation to accommodate PCB board placement deviations.

[0057] The system also includes a charge neutralization unit, which is used to neutralize the charge generated by laser irradiation during exposure on non-conductive substrates to prevent image distortion. The system also includes a stitching accuracy detection unit, which is used to detect the stitching accuracy of the minimum resolution line width to ensure image quality in the stitching area.

[0058] A specific embodiment of the present application is given below:

[0059] The technology is applicable to the semiconductor and printed circuit board (PCB) manufacturing fields, and is particularly applicable to the technology of achieving high-precision graphic exposure by coordinating static projection and precise micro-displacement in laser direct imaging (LDI) systems.

[0060] Implementation steps:

[0061] Preparation: Secure the PCB substrate to a piezoelectric ceramic drive platform or a linear motor drive platform, ensuring positioning accuracy of ±0.1-1.0μm. Check that the laser, DMD control board, DMD, optical lens, alignment camera, processor, suction cup, motion platform, and marble base are functioning properly.

[0062] Graphic data loading: The circuit graphic data is loaded into the DMD through the processor, and the ultraviolet light source (wavelength 365nm, 405nm or other wavelengths, or wide-spectrum LED light source) is turned on.

[0063] CCD positioning: The CCD moves to the positions of the four mark points to locate the position of the entire PCB board and analyze the size (expansion and contraction) of the PCB board. The expansion and contraction values ​​are sent to the DMD to fine-tune the image size and deformation, and differentially adjust the light and shadow size of the circuit diagram to adapt to the actual size and shape of the PCB board. At the same time, the positioning data is sent to the operation control platform to correct the position of the PCB board and align it with the light and shadow position.

[0064] Synchronous triggering: The control platform executes CCD data and corrects the PCB board position, starting static exposure (t = 0). At the same time, the platform moves in a triangular wave path with an amplitude of ±25μm and a frequency of 10Hz.

[0065] Micro-displacement exposure: During the exposure period T (e.g., T = 2 seconds), the motion control subsystem drives the substrate-carrying platform to perform N (e.g., N = 10) high-frequency micro-displacements. The displacement path reciprocates along the diagonal direction of the projected image (preferably 45°), with a displacement amplitude of δ = ±25 μm and a displacement frequency of f ≥ 5 Hz.

[0066] Exposure completed: After completing 10 micro-displacement cycles, turn off the light source (t = 2 seconds) to complete a single exposure. After completing the exposure of a single area, proceed to the next exposure position and repeat the micro-displacement exposure action until the entire PCB surface is exposed.

[0067] Effect detection:

[0068] Alignment cameras and inner-layer MARK cameras are used to detect exposure effects, ensuring that edge roughness reaches 0.8μm, data volume is reduced to 200GB / h, and exposure efficiency is increased to 98%.

[0069] Measured results:

[0070] The jagged edges are transformed into smooth transition zones, with a line width consistency error of ≤±1.2μm (compliant with IPC-6012 Class 3). Electron microscopy images show that the jagged edges are effectively smoothed and edge roughness is significantly reduced.

[0071] Technical effects:

[0072] Compared with traditional oblique scanning schemes, the method of the present invention significantly reduces system complexity while maintaining resolution, reducing edge roughness from 3.2μm to 0.8μm, data volume from 1.2TB / h to 200GB / h, and exposure efficiency from 85% to 98%.

[0073] This example demonstrates an efficient, high-precision pattern exposure method suitable for semiconductor and printed circuit board manufacturing, with broad industrial application prospects. By combining static projection with dynamic micro-displacement, this method effectively improves exposure accuracy and production efficiency, reduces data processing complexity, and meets the needs of high-precision manufacturing.

[0074] The core of the invention in this application includes:

[0075] During the static projection exposure period (T = 0.1-5 seconds), edge smoothing is achieved through the following coordinated control:

[0076] 1. DMD subsystem

[0077] -Load the entire scene's graphics data and maintain a static projection state

[0078] -The pixel unit size projected onto the exposure object surface is A×A (typically A=50μm)

[0079] 2.**Motion Control Subsystem**

[0080] - Drive the platform carrying the substrate to perform N times (N≥5) high-frequency micro-displacement in the XY plane

[0081] -Displacement path: reciprocating along the diagonal direction of the projected image (preferably 45°) or up and down, left and right, or in a curve

[0082] - Displacement amplitude: δ = + / - k × A / 2 (k = 0.5-1.0, preferably δ = + / - 25 μm)

[0083] -Displacement frequency: f≥1 / (T / N) (when T=2s, N=10, f≥5Hz)

[0084] Implementation steps include:

[0085] 1. Fix the PCB substrate on a piezoelectric ceramic drive platform or a linear motor drive platform (positioning accuracy ±0.1-1.0mm). After CCD positioning correction, the position deviation between the PCB board and the optical machine light and shadow is less than 2μm.

[0086] 2. The DMD loads the circuit pattern and turns on the ultraviolet light source (wavelength 365nm, 405nm or other wavelengths, or a wide-spectrum LED light source).

[0087] 3. Synchronous trigger:

[0088] - Start static exposure (t=0);

[0089] - The platform moves in a triangular wave path (amplitude ±25 μm, frequency 10 Hz).

[0090] 4. After completing 10 micro-displacement cycles, turn off the light source (t = 2s).

[0091] 5. Repeat steps 3-4 to complete the exposure of each area of ​​the PCB (the exposure area can be freely designed according to the DMD arrangement).

[0092] In this process, the processor specifically prohibits the DMD from refreshing the graphics, and only eliminates pixel aliasing through platform micro-displacement. The displacement amount (movement amplitude) δ = 25 μm each time, the exposure period T is set to 0.5s–5s (different inks have different exposure times), the number of displacements N is set to 5–60 times, and the displacement frequency f = N / T ≥ 5 Hz to ensure that the edge roughness Ra ≤ 5% of the pixel unit size (2.5 μm).

[0093] The innovations of this application include:

[0094] Eliminating oblique scanning requires a high-frequency DMD optical module (saving 35% of the cost) and reducing the DMD data update rate from the KHz level to a single load.

[0095] Physical-digital collaborative optimization: Natural pixel superposition is achieved through mechanical micro-displacement, which is 100 times more efficient than software anti-aliasing algorithms.

[0096] The extended application is suitable for wafer-level packaging (WLP) and can be extended to 3D printing surface projection curing.

[0097] like Figure 2The embodiment of the present application also provides an exposure method for a semiconductor packaging patterning lithography system, which may include:

[0098] S1, coating photoresist on the substrate to be exposed and performing pre-baking;

[0099] S2, load the pre-baked substrate into the LDI system and maintain a stable exposure environment to ensure accurate pattern transmission;

[0100] S3, load the entire field pattern into the DMD at one time and lock it. The laser is continuously illuminated for T seconds. During this period, the motion platform performs N round-trip micro-displacements to complete N sub-pixel offset exposures on the substrate, thereby smoothing the jagged edges through light intensity integration.

[0101] S4, developing and etching the substrate after photolithography to form the desired circuit or pattern;

[0102] S5, repeating steps S3 and S4 to complete the manufacturing of the multi-layer pattern.

[0103] In this embodiment, the processor prohibits the DMD from refreshing the graphics, and only eliminates pixel aliasing through micro-displacement of the platform. The displacement amount (movement amplitude) of each time is δ = 25μm, the exposure period T is set to 0.5s-5s (different inks have different exposure times), the number of displacements N is set to 5-60 times, and the displacement frequency f = N / T ≥ 5Hz to ensure that the edge roughness Ra ≤ 5% of the pixel unit size (2.5μm). The various technical features of the above-mentioned embodiments can be combined arbitrarily. For the sake of simplicity, not all possible combinations of the various technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0104] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A projection imaging lithography system based on LDI, characterized in that: The system comprises: The laser is located at the top of the system and is used to emit ultraviolet light, whose beam is projected onto the DMD through a uniform light lens; The DMD control board is used to control the loading of DMD graphic data and load the entire field of graphic data only once during the entire exposure period T, and keep the DMD projection pattern static and constant. Unlike the oblique scanning method, it is no longer necessary to refresh the DMD projection pattern at high speed; DMD, located on the object plane of the optical lens, is used to receive the light beam from the laser or LED and perform full-field graphic projection in a static state; The optical lens is located below the DMD and is used to magnify or reduce the pattern on the DMD to the required optical magnification and project it onto the substrate to be exposed; The alignment axis is located between the optical lens and the alignment camera and is used to assist the alignment camera in precise alignment; Alignment cameras, including calibration cameras and MARK cameras, are set on one side of the optical lens to achieve alignment accuracy for inner and outer layer exposure; A processor is used to process exposure data and control the DMD to maintain static projection during the exposure period T, while driving the motion platform to perform N high-frequency sub-pixel micro-displacements. The processor includes a static projection + micro-displacement coordinated control algorithm that prohibits the DMD from refreshing image data during the exposure period T, and implements light intensity integral anti-aliasing only through micro-displacements of the motion platform. The motion platform, located at the bottom of the system, is used to perform N reciprocating micro-displacements along the X, Y, or a combination thereof during static projection. This smoothes jagged edges through multiple micro-offset exposures, achieving sub-pixel precision. Based on CCD positioning data, the motion control platform moves the first area of ​​the PCB on the carrier to the exposure area. At this point, it sends a signal to the DMD to project the pattern light and shadow of the first area. Simultaneously, the control platform vibrates back and forth within a set amplitude, accelerating and decelerating until the vibration time exceeds the system-set exposure time. This eliminates sub-pixel deviations when the exposure position is between non-integer multiples of the pixel size, and also smooths the staircase jagged edges of individual pixels on the circuit pattern on the PCB. The laser, DMD control board, DMD, optical lens, alignment camera and processor are connected through internal related optoelectronic units to achieve data transmission and control signal transmission; the laser can also use a wide-spectrum UV LED, and the motion platform is connected to the marble base through a high-precision guide rail or air flotation system to achieve smooth movement.

2. The projection imaging lithography system according to claim 1, wherein: The motion platform includes a laser interferometer or grating ruler positioning system, which is used to provide accurate position feedback of the motion platform to achieve high-precision exposure and alignment.

3. The projection imaging lithography system according to claim 1, wherein: The alignment camera includes a complete set of camera lens and lighting solutions, which can adapt to the precise positioning of PCB board marks of different types or colors and compensate for board placement errors.

4. The projection imaging lithography system according to claim 1, wherein: The micro-displacement path of the motion platform can move back and forth along the x-axis, y-axis, or a combination of the two axes, with a motion amplitude of half the pixel size. The displacement amplitude δ = ±25 μm, the period Δt = T / N, and when T = 2 s and N = 10 times, Δt = 0.2 s, with a frequency f = 5 Hz. During the exposure process, the micro-movement of the motion platform can eliminate edge jaggedness and achieve a smooth effect.

5. The projection imaging lithography system according to claim 1, wherein: The DMD control board includes a real-time feedback controller, which is used to receive monitoring data from the alignment camera and adjust the DMD's graphic projection parameters based on the data; the real-time feedback controller receives the alignment error output by the alignment camera and corrects the micro-displacement starting coordinates in real time to ensure that the graphic edge overlap error after N displacements is ≤±10% of the size of a single pixel.

6. The projection imaging lithography system according to claim 1, wherein: The inner or outer layer MARK camera specifically includes a MARK detection unit, which is used to detect the alignment mark during exposure of the inner or outer layer to ensure accurate alignment of the inner layer pattern and the outer layer pattern.

7. The projection imaging lithography system according to claim 1, wherein: The system further comprises a splicing accuracy detection unit, which is used to detect the splicing accuracy of the minimum resolution line width to ensure the graphic quality of the splicing area; The system also includes a marble base, located at the bottom of the entire system, which is used to provide stable support for the system and reduce mechanical vibration errors.

8. An exposure method for an LDI projection imaging lithography system according to any one of claims 1 to 7, characterized in that: include: S1, coating photoresist on the substrate to be exposed and performing pre-baking; S2, load the pre-baked substrate into the LDI system and maintain a stable exposure environment to ensure accurate pattern transmission; S3, load the entire field pattern into the DMD at one time and lock it. The laser is continuously illuminated in the exposure area for T seconds. During this period, the motion platform performs N round-trip micro-displacements to complete N sub-pixel offset exposures on the substrate, thereby smoothing the jagged edges through light intensity integration; S4, developing and etching the substrate after photolithography to form the desired circuit or pattern; S5, repeating steps S3 and S4 to complete the manufacturing of the multi-layer pattern.

9. The exposure method of the projection imaging lithography system according to claim 8, characterized in that: In step S3, the processor prohibits DMD from refreshing the pattern and only eliminates pixel aliasing by micro-displacing the platform. The displacement amount δ = 25 μm each time, the exposure period T is set to 0.5s–5s, the number of displacements N is set to 5–60 times, and the displacement frequency f = N / T ≥ 5 Hz to ensure that the edge roughness Ra ≤ 5% of the pixel unit size.

Images