An adjusting lens group and method for improving illumination uniformity

Abstract

The present invention discloses an adjusting lens group and method for improving illumination uniformity, including an adjusting lens group for improving illumination uniformity. The lens group includes a first lens, a second lens, a lens barrel, an optical fiber fixing seat, and a three-dimensional adjusting mechanism. Both the first lens and the second lens are plano-convex lenses. The first lens and the second lens are respectively arranged in lens mounts, and the lens mounts are arranged in the lens barrel, and the convex surfaces of the two lenses are arranged opposite to each other. An optical fiber installation lens barrel is arranged at the upper end of the lens barrel, and the optical fiber fixing seat is installed in the optical fiber installation lens barrel. The three-dimensional adjusting mechanism is arranged between the optical fiber installation lens barrel and the optical fiber fixing seat. The three-dimensional adjusting mechanism includes a tightening nut, a fixing nut, and a ball head hexagon adjuster. The adjustment method of the lens group is simple and has low cost, so as to solve the problems in the existing laser direct imaging lithography system, such as uneven energy distribution of the exposure spot and reduced product yield due to unstable light output of the fiber laser and insufficient adjustment accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of lithography equipment, and specifically to an adjustment lens group and method for improving illumination uniformity. Background Art

[0002] Optical lithography is a technology that uses light to project and replicate a mask pattern. With the increasing demand for devices such as microsensors and micro-nano optoelectronics in scientific research, compared with traditional lithography machines, the digital maskless lithography technology using a digital micromirror device (DMD) spatial light modulator allows users to have a higher degree of freedom in the design of patterns, thereby significantly increasing the complexity of lithography patterns.

[0003] Currently, in the field of lithography equipment for processing PCB boards, the laser direct imaging (LDI) lithography technology using UV light is widely adopted. Compared with the traditional photographic film imaging process, maskless lithography can reduce the process flow by more than 60%. Thanks to the omission of steps such as making photographic plates in the process, small-batch express board companies benefit significantly from the direct imaging technology.

[0004] In the field of lithography exposure, the energy uniformity of the lens directly affects the actual exposure ability of the lens. Especially in large-area exposure and the generation of complex patterns, the insufficient light intensity in the exposure edge area and the decline in pattern clarity directly affect the product yield and process stability. In the actual production process, due to processing errors and the light output problems of the laser itself, the uniformity of the produced lenses is lower than the target requirements. This directly leads to a decrease in production yield and a significant increase in costs. The uniformity problem has become a major problem restricting the performance of lithography exposure lenses; moreover, the existing fiber laser adjustment structure is not reasonably designed, resulting in energy loss and spot distortion problems in the incident light beam, and the overall light energy utilization rate is low, which cannot meet the strict requirements of high-precision lithography for uniform energy distribution and beam quality. The existing adjustment lens group has a complex structure and a large volume, making it difficult to be applied to modern miniaturized and integrated laser direct imaging lithography systems, affecting the integration and process accuracy of the whole machine.

[0005] However, most of the existing uniform illumination technologies are applied in the fields of LCD display and projection, and it is difficult to meet the high consistency requirements of the lithography exposure system for laser energy distribution; for example, the patent publication number CN222439827U discloses a uniform illumination device for compensating the relative illuminance loss of a lens, including a light source, a light distribution lens, an LCD screen, a front Fresnel lens, a rear Fresnel lens, and a projection lens, which is applied in the fields of LCD display and projection. The technical means uses a light distribution lens, a Fresnel lens group, etc. to improve the energy distribution of the projection system, which is a simple projection imaging and cannot meet the application in the field of lithography exposure, and cannot solve the uniformity problem in the high-precision laser exposure system in the lithography field. Similarly, the patent publication number CN117440141A also has the above problems.

[0006] Patent Publication No. CN103885297B discloses a method for correcting the illumination uniformity of a lithography machine exposure system. This method adjusts the light intensity of the center and edge regions of a rectangular illumination spot by moving the last lens of the condenser lens group along the optical axis direction to correct the illumination uniformity of the exposure spot. However, it has the following defects: This method only relies on adjusting the position of the condenser lens group lens in the single-axis (Z-axis) direction and cannot achieve X and Y direction adjustments. The adjustment dimension is limited and it cannot handle the complex offset problems existing at the light output end of the fiber laser. This solution is mainly applied to the step-and-scan lithography machine system and is difficult to adapt to the requirements of the laser direct imaging (LDI) system for the collimation of the fiber laser output light and the control of NA (numerical aperture) for traditional mask pattern exposure. Only by moving the position of the condenser lens group lens to adjust the light intensity distribution, it is impossible to effectively optimize the light output angle and beam shape of the fiber laser itself, and there is still a risk of insufficient spot uniformity.

[0007] Patent Publication No. CN116414009A discloses a device for correcting the uniformity of a lithography machine illumination system. This device includes a correction plate composed of a number of microcrystalline units with independently controllable transmittance, and dynamically corrects the non-uniformity of the integrated light intensity of the light field by adjusting the transmittance of the microcrystalline units, simplifying the structure of the traditional "finger array type" shielding device and having a real-time adjustment function. However, this technical solution is mainly applied to the mask projection lithography machine and belongs to the light field intensity shielding type adjustment method. This solution has the following problems: It is impossible to perform NA adjustment or spatial adjustment of the emission angle on the light output end of the fiber laser. The electronic control system of the adopted microcrystalline unit is complex and the hardware integration degree is high, resulting in increased costs and maintenance difficulties. The transmittance adjustment still relies on the light intensity weakening mode and it is difficult to balance the requirements of high energy utilization rate. It is difficult to be applied to the laser direct imaging lithography system with a compact structure and optimized power consumption; the authorized announcement number: CN103809382B discloses a light homogenization adjustment device for a lithography apparatus, which uses an optical lens to form a closed volume filled with a conductive solution, and adjusts the refractive index of the conductive solution through an electric field control unit to achieve dynamic adjustment of the light transmittance, and can cooperate with a detector to correct the light field uniformity in real time, mainly applied to the conjugate plane of the mask; it has the following defects: The structure is complex, the hardware dependence is high, and the control system is difficult to integrate and maintain; Adjusting by the light intensity weakening method results in a decrease in the light energy utilization rate; It does not have the three-dimensional adjustment ability of the light output end of the fiber laser and cannot optimize the laser beam characteristics; It is only applicable to the traditional mask lithography system and is not suitable for laser direct imaging (LDI) applications. Patent Publication No. CN103488061B is for the EUV extreme ultraviolet lithography system to solve the complex system matching problem; It uses optical path simulation and compound eyeglass group adjustment; The system is complex and is for the exposure requirements of high-end chip manufacturing; It cannot meet the requirements of solving the above problems.

[0008] In addition, the existing technology relies on manual adjustment of the position of the lens group to improve the spot uniformity, which has problems such as complex adjustment, poor repeatability, and low efficiency, and it is difficult to meet the requirements of modern lithography. To address the above problems, an adjustment lens group and method for improving the illumination uniformity are proposed. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the existing defects and provide an adjustment lens group and method for improving the illumination uniformity, so as to solve the problems in the existing laser direct imaging lithography system, such as uneven energy distribution of the exposure spot and reduced product yield due to unstable light output of the fiber laser and insufficient adjustment accuracy. The adjustment method of this lens group is simple and low-cost, which can improve the lens exposure uniformity from 85% to 95%, and enhance the uniformity of the lens by 11.7%, effectively solving the problems in the background technology.

[0010] To achieve the above object, the present invention provides the following technical solution: An adjustment lens group and method for improving the illumination uniformity, including an adjustment lens group for improving the illumination uniformity. The lens group includes a first lens, a second lens, a lens barrel, a fiber optic fixing seat, and a three-dimensional adjustment mechanism. Both the first lens and the second lens are plano-convex lenses. The first lens and the second lens are respectively arranged in lens mounts, and the lens mounts are arranged in the lens barrel, and the convex surfaces of the two lenses are arranged opposite to each other. An optical fiber installation lens barrel is provided at the upper end of the lens barrel, the fiber optic fixing seat is installed in the optical fiber installation lens barrel, and the three-dimensional adjustment mechanism is arranged between the optical fiber installation lens barrel and the fiber optic fixing seat. The three-dimensional adjustment mechanism includes a tightening nut, a fixing nut, and a ball head hexagon regulator. The fixing nut is arranged in the optical fiber installation lens barrel, and the fiber optic fixing seat is installed on the fixing nut. A threaded bushing is arranged in the circumferential direction of the optical fiber installation lens barrel, the ball head hexagon regulator is installed in the threaded bushing, and the ball head end of the ball head hexagon regulator corresponds to the fixing nut. The tightening nut is arranged on the fiber optic fixing seat, and the tightening nut and the fixing nut form a locking mechanism. A tightening nut adjustment hole is arranged on the tightening nut, a fixing seat adjustment hole is arranged on the fiber optic fixing seat, and a nut is arranged above the optical fiber installation lens barrel. The adjustment method includes the following specific steps:

[0011] Step 1: Install the optical lens group. The first lens and the second lens are respectively installed in the lens mounts, so that the first lens and the second lens are assembled in the lens barrel through the lens mounts with their convex surfaces facing each other, forming a double-lens combination system.

[0012] Step 2: Install the three-dimensional adjustment mechanism. Insert the threaded bushing into the optical fiber installation lens barrel, then insert the ball head hexagon regulator into the threaded bushing. Fix the optical fiber installation lens barrel to the lens barrel with connecting screws. Install the fiber optic fixing seat on the fixing nut, place the fixing nut into the optical fiber installation lens barrel, tighten the fixing nut with the ball head hexagon regulator, screw the tightening nut onto the fiber optic fixing seat, and then tighten the nut.

[0013] Step 3: Adjustment in the X and Y directions. Loosen the ball-head hexagon adjuster in one direction slightly, and then tighten the ball-head hexagon adjuster on the opposite side. Use this method to adjust the eccentricity.

[0014] Step 4: Adjustment in the Z direction. First, use a wrench to loosen the lock nut through the nut adjustment hole, and then use a wrench to rotate and adjust the height of the optical fiber fixing seat through the fixing seat adjustment hole.

[0015] Step 5: Locking operation. After completing the three-dimensional adjustment, use the double-nut structure to lock the Z-direction adjustment position. A wrench can be used to tighten the lock nut through the nut adjustment hole, and the ball-head hexagon adjuster is used to lock the adjustment positions in the X and Y directions. After fixing their positions, then tighten the nuts.

[0016] Further, a vertical convex groove is provided in the circumferential direction of the lens holder. A limit card slot is provided at the bottom of the vertical convex groove. Fixed rings are provided in the circumferential direction of the first lens and the second lens. Connecting ribs are provided in the circumferential direction of the fixed rings. The first lens and the second lens are respectively stuck in the vertical convex grooves of the lens holder through the connecting ribs. Rubber blocks are provided at the outer ends of the connecting ribs, and the rubber blocks are rotated and snapped into the limit card slots.

[0017] Further, an annular inner convex platform is provided in the inner circumferential direction of the lens holder. The bottom surfaces of the first lens and the second lens are respectively pasted on the annular inner convex platform of the lens holder.

[0018] Further, a bottom plate is provided at the lower end of the optical fiber mounting barrel. The fixing nut abuts against the bottom plate, and the bottom plate presses on the lens holder. A central hole is provided at the center of the bottom plate, and upward protrusions are provided at the edge of the central hole. The lower end of the optical fiber fixing seat is located in the central hole.

[0019] Further, adjustment holes are evenly provided in the circumferential direction on the side surface of the optical fiber mounting barrel. At least four adjustment holes are provided, and a threaded bushing is provided in the adjustment hole. The ball-head hexagon adjuster is screwed into the threaded bushing.

[0020] Further, the first lens and the second lens are made of fused silica material.

[0021] Further, the height of the optical fiber mounting barrel is 8.12 millimeters, and the diameter is 32 millimeters.

[0022] Further, the adjustment accuracy of the ball-head hexagon adjuster is ±5 microns.

[0023] Further, for exposure uniformity detection and correction, after the adjustment is completed, the illumination uniformity of the light beam emitted by the fiber laser is detected by a detection device. When the uniformity does not meet the set standard, repeat Step 3 and Step 4 until the exposure uniformity meets the requirements.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. The first lens and the second lens adopt a double plano-convex lens structure and are combined with their convex surfaces facing each other, effectively optimizing the shaping and collimation effects of the laser fiber output beam; the double-lens structure realizes the control of the divergence angle of the laser beam by adjusting the numerical aperture of the fiber laser, making the light energy distribution more uniform; the adjustment lens group can increase the illumination uniformity of the laser beam by 11.7%, significantly reducing the energy hot spots and dark areas during the exposure process, and improving the consistency and clarity of the edges of the exposed pattern.

[0026] 2. The three-dimensional adjustment mechanism adopts a ball-head hexagon regulator combined with a threaded bushing design to achieve high-precision adjustment in the X, Y, and Z directions, compensating for the eccentricity and height inconsistency problems caused by machining errors or assembly errors; through the double-nut locking mechanism such as tightening nuts, fixing nuts, and nuts, it ensures the stable fixation of the fiber laser after adjustment, avoiding displacement or spot offset of the system during operation; after adopting the three-dimensional adjustment structure, the stability of the system is enhanced during long-term operation, the fluctuation range of the exposure quality is reduced, and the process consistency and product yield of the lithography system are significantly improved.

[0027] 3. The lens holder adopts a vertical convex groove and a limit card slot structure design. The first lens and the second lens are mechanically clamped and fixed through connecting ribs and rubber blocks, avoiding problems such as lens offset or detachment caused by glue aging, moisture, or temperature changes; this mechanical fixation method can ensure the high stability and durability of the lens during operation, reduce the maintenance frequency, and extend the service life of the optical lens group.

[0028] 4. The height of the lens group is only 8.12 mm and the diameter is 32 mm, which is suitable for a miniaturized and high-precision laser direct imaging lithography system, meeting the current requirements of high-end microelectronic manufacturing equipment for miniaturization and integration. Moreover, the modular design facilitates system installation, debugging, and maintenance, reducing production and operation costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic cross-sectional structure diagram of the present invention;

[0030] Figure 2 is an axonometric view of the present invention.

[0031] Figure 3 is a schematic diagram of the structure of the lens holder of the present invention Figure 1 ;

[0032] Figure 4 is a schematic diagram of the structure of the lens holder of the present invention Figure 2 ;

[0033] Figure 5 is a schematic enlarged structure diagram at A of the present invention;

[0034] Figure 6 Schematic diagram of the fixed ring structure of the present invention;

[0035] Figure 7 Schematic diagram of the optical fiber installation lens barrel structure of the present invention;

[0036] Figure 8 Schematic diagram of the optical path of the double-lens combination of the present invention.

[0037] In the figure: 1 lens seat, 2 ball head hexagon adjuster, 3 optical fiber installation lens barrel, 4 tightening nut, 5 optical fiber fixing seat, 6 nut, 7 threaded bushing, 8 fixing nut, 9 first lens, 10 second lens, 11 lens barrel, 12 connecting screw, 13 fixing seat adjustment hole, 14 tightening nut adjustment hole, 15 annular inner convex platform, 16 vertical convex groove, 17 limit card slot, 18 connecting rib, 19 rubber block, 20 fixing ring, 21 bottom plate, 22 center hole, 23 adjustment hole. Specific embodiments

[0038] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0039] Please refer to Figure 1-8, the present invention provides a technical solution: an adjusting lens group and method for improving light illumination uniformity, including an adjusting lens group for improving light illumination uniformity. The lens group includes a first lens 9, a second lens 10, a lens barrel 11, an optical fiber fixing seat 5, and a three-dimensional adjusting mechanism. Both the first lens 9 and the second lens 10 are plano-convex lenses. The first lens 9 and the second lens 10 are respectively arranged in a lens holder 1, and the lens holder 1 is arranged in the lens barrel 11, and the convex surfaces of the two lenses are arranged opposite to each other. A brand-new double-lens structure of the first lens 9 and the second lens 10 is adopted to improve light illumination uniformity. By the way of arranging the two convex surfaces opposite to each other, the NA of the fiber laser is enlarged or reduced, thereby initially improving the light output problem of the fiber laser. The lens can directly purchase commercial finished lenses, with relatively low cost. An optical fiber installation lens barrel 3 is arranged at the upper end of the lens barrel 11, and the optical fiber fixing seat 5 is installed in the optical fiber installation lens barrel 3. The optical fiber installation lens barrel 3 is used to fix the light output position of the fiber laser. The three-dimensional adjusting mechanism is arranged between the optical fiber installation lens barrel 3 and the optical fiber fixing seat 5. The three-dimensional adjusting mechanism includes a tightening nut 4, a fixing nut 8, and a ball head hexagon adjuster 2. The fixing nut 8 is arranged in the optical fiber installation lens barrel 3, and the optical fiber fixing seat 5 is installed on the fixing nut 8. A threaded bushing 7 is arranged in the circumferential direction of the optical fiber installation lens barrel 3. The ball head hexagon adjuster 2 is installed in the threaded bushing 7, and the ball head end of the ball head hexagon adjuster 2 corresponds to the fixing nut 8. The tightening nut 4 is arranged on the optical fiber fixing seat 5. The tightening nut 4 and the fixing nut 8 form a locking mechanism. The tightening nut 4 locks the optical fiber fixing seat 5 to prevent the optical fiber from shifting. A tightening nut adjustment hole 14 is arranged on the tightening nut 4, and a fixing seat adjustment hole 13 is arranged on the optical fiber fixing seat 5. A nut 6 is arranged above the optical fiber installation lens barrel 3, and the nut 6 is fixed at the top. Cooperating with the tightening nut 4, the final locking operation is completed. The adjusting method includes the following specific steps:

[0040] Step 1: Install the optical lens group. The first lens 9 and the second lens 10 are respectively installed in the lens holder 1, so that the first lens 9 and the second lens 10 are assembled in the lens barrel 11 through the lens holder 1 in a manner that the convex surfaces are opposite to each other, forming a double-lens combination system;

[0041] Step 2: Install the three-dimensional adjusting mechanism. Install the threaded bushing 7 into the optical fiber installation lens barrel 3, then install the ball head hexagon adjuster 2 into the threaded bushing 7. Fix the optical fiber installation lens barrel 3 on the lens barrel 11 with a connecting screw 12. Install the optical fiber fixing seat 5 on the fixing nut 8. Put the fixing nut 8 into the optical fiber installation lens barrel 3, and tighten the fixing nut 8 with the ball head hexagon adjuster 2. Screw the tightening nut 4 onto the optical fiber fixing seat 5, and then tighten the nut 6;

[0042] Step 3: Adjust in the X and Y directions. Loosen slightly the ball head hexagon adjuster 2 in one direction, and then tighten the ball head hexagon adjuster 2 on the opposite side to adjust the eccentricity in this way;

[0043] Step 4: Z-direction adjustment. First, use a wrench to loosen and then tighten the lock nut 4 through the lock nut adjustment hole 14, and then use a wrench to rotate and adjust the height of the optical fiber fixing seat 5 through the fixing seat adjustment hole 13.

[0044] Step 5: Locking operation. After completing the three-dimensional adjustment, use the double-nut structure to lock the Z-direction adjustment position. A wrench can be used to tighten the lock nut 4 through the lock nut adjustment hole 14. The ball head hexagon adjuster 2 is used to lock the adjustment positions in the X and Y directions. After fixing their positions, then tighten the nut 6.

[0045] The present invention utilizes the double plano-convex lens combination system constructed by the first lens 9 and the second lens 10. By arranging the convex surfaces facing each other, the shaping and collimation functions of the incident laser beam are realized, the numerical aperture NA and the beam divergence angle at the output end of the fiber laser are optimized, and the illumination uniformity is improved. The three-dimensional adjustment mechanism is based on the combination of the ball head hexagon adjuster 2 and the threaded bushing 7 to achieve high-precision fine adjustment in the X, Y, and Z directions, effectively calibrating the optical axis offset and incident angle problems of the fiber laser. The lock nut 4 and the fixing nut 8 in the adjustment mechanism form a reliable locking system to ensure the overall structure is stable and does not loosen after the adjustment. Through step-by-step adjustment and locking, the collimation of the laser beam and the optimization of the illumination uniformity are achieved.

[0046] The circumferential direction of the lens holder 1 is provided with a vertical convex groove 16, and the bottom of the vertical convex groove 16 is provided with a limit card slot 17. The circumferential direction of the first lens 9 and the second lens 10 is provided with a fixing ring 20, and the circumferential direction of the fixing ring 20 is provided with a connecting rib 18. The first lens 9 and the second lens 10 are respectively stuck in the vertical convex groove 16 of the lens holder 1 through the connecting rib 18. This method reduces unnecessary shielding of the lens and makes full use of the lens. The outer end of the connecting rib 18 is provided with a rubber block 19, and the rubber block 19 is vulcanized on the connecting rib 18. The rubber block 19 is rotated and snapped into the limit card slot 17. Since the size of the rubber block 19 is larger than the size of the limit card slot 17, the rubber block 19 will deform when snapped into the limit card slot 17, and then an extrusion force will be generated between the rubber block 19 and the limit card slot 17, and the rubber block 19 will be fixed in the limit card slot 17 and will not rotate or shake, which is suitable for lithography systems with high stability and seismic requirements. This method does not require glue fixation, completely relies on mechanical force for fixation, and will not fall off after fixation, which has a better effect than glue fixation.

[0047] This embodiment provides stable positioning and locking functions by designing vertical convex grooves 16 and limit card slots 17 on the lens holder 1; fixing rings 20 are added to the first lens 9 and the second lens 10 in their circumferential directions, and connecting ribs 18 extend into the vertical convex grooves 16 to complete preliminary fixation through mechanical plugging; rubber blocks 19 are installed at the outer ends of the connecting ribs 18, and the rubber blocks 19 are inserted into the limit card slots 17 by rotation; when the rubber blocks 19 are snapped into the limit card slots 17, due to their size being slightly larger than that of the limit card slots 17, deformation occurs to form an elastic pressing force, achieving effective mechanical locking and preventing the lenses from loosening or shifting due to vibration or temperature changes; this structure does not require the use of adhesives, improving assembly efficiency and reliability, and enhancing durability and environmental adaptability.

[0048] The number and spacing of the vertical convex grooves 16 can be optimized and adjusted according to the diameters of the first lens 9 and the second lens 10 to improve the adaptability of the structure to lenses of different specifications.

[0049] The rubber blocks 19 can be made of different materials, such as silica gel, fluororubber, etc., to enhance high-temperature resistance, corrosion resistance, or anti-aging performance to meet the requirements of different environmental conditions.

[0050] The connecting ribs 18 can be designed in different shapes, such as T-shaped, L-shaped, or arc-shaped, to adapt to the requirements of different mechanical strengths and assembly convenience.

[0051] If there are higher requirements for disassembly and assembly efficiency, a quick-release structure or positioning mark can be added to the rubber blocks 19 to assist in achieving rapid and precise installation.

[0052] An annular inner convex platform 15 is provided on the inner circumferential direction of the lens holder 1, and the bottom surfaces of the first lens 9 and the second lens 10 are respectively pasted on the annular inner convex platform 15 of the lens holder 1. This installation method is simple, but it is prone to falling off after a long time, and the annular inner convex platform 15 will form a certain blockage in the circumferential direction of the lens, thereby increasing the size of the lens group. This method is suitable for systems that have low requirements for size, require easy production, and low cost. This structure is easy to install and has low cost, and is suitable for systems with low requirements for size.

[0053] The type of adhesive can be selected according to application requirements with adhesives of different performances, such as epoxy resin, UV curable glue, or silicone glue, to improve heat resistance, UV resistance, and moisture resistance.

[0054] To improve the bonding firmness and accuracy, micro-positioning convex points or chamfer structures can be added to the annular inner convex platform 15 of the lens holder 1 to achieve higher-precision mechanical limiting.

[0055] At the lower end of the optical fiber installation barrel 3, a bottom plate 21 is provided. The fixing nut 8 abuts against the bottom plate 21, and the bottom plate 21 presses on the lens holder 1. The function of this bottom plate not only serves to support the double-nut structure but also to firmly press the lens holder 1, reducing the size of the lens group from the structure. The overall structure is compact and reasonable, which helps to control the external dimensions of the optical components and meet the integration requirements of a miniaturized lithography system. A central hole 22 is provided at the center of the bottom plate 21, and upward protrusions are provided at the edge of the central hole 22. The lower end of the optical fiber fixing seat 5 is located in the central hole 22, which serves to limit the optical fiber fixing seat 5 and prevent the optical fiber fixing seat 5 from being overly eccentric.

[0056] Adjusting holes 23 are evenly arranged in the circumferential direction on the side surface of the optical fiber installation barrel 3. At least four adjusting holes 23 are provided. The threaded bushing 7 is arranged in the adjusting hole 23, and the ball head hexagon adjuster 2 is screwed into the threaded bushing 7. The external dimensions of the optical fiber installation barrel 3 are a height of 8.12 mm and a diameter of 32 mm, which are adapted to a miniaturized laser direct imaging lithography system and achieve high-precision three-dimensional adjustment to compensate for the errors caused by machining. The incident light source is adjusted in three directions of X, Y, and Z, and the light energy utilization rate is increased by 11.7%.

[0057] The number of the adjusting holes 23 can be increased to six or eight according to application requirements to improve the adjustment flexibility and stability of a more complex system.

[0058] The installation method of the threaded bushing 7 can adopt a snap or quick-insert structure to improve the maintenance efficiency and facilitate the replacement and maintenance of the adjusting mechanism.

[0059] It is also possible to add an anti-loosening design for the adjusting holes 23 and the ball head hexagon adjuster 2, such as a locking nut or a lock washer, to avoid the decline of the adjustment accuracy caused by vibration or thermal expansion and contraction.

[0060] The first lens 9 and the second lens 10 are made of fused silica material; in this embodiment, by selecting the fused silica material to manufacture the first lens 9 and the second lens 10, the overall performance of the optical system is optimized. Fused silica has an extremely low coefficient of thermal expansion and excellent thermal stability, and can maintain the stability of dimensions and shape under the conditions of high temperature and high energy density laser irradiation, avoiding optical distortion caused by temperature changes.

[0061] The high light transmittance of fused silica covers the deep ultraviolet to near-infrared band from about 180 nm to 2500 nm, ensuring that the laser has a low light absorption rate in different bands, significantly reducing the laser energy loss; its high uniformity and low impurity content reduce the scattering and absorption phenomena in the optical system, improving the beam quality and system efficiency.

[0062] In addition, fused quartz has strong corrosion resistance and radiation resistance, making it suitable for environments with extremely high requirements for the performance of optical components such as lithography equipment; by using fused quartz materials, the optical performance and working life of the adjustment lens group system can be further improved; compared with traditional optical glass, fused quartz has a higher laser damage threshold and is suitable for high-energy density application scenarios such as laser direct imaging LDI systems, improving product process accuracy and production efficiency.

[0063] In addition to fused quartz, the first lens 9 and the second lens 10 can be made of sapphire, barium titanate glass or high refractive index optical glass according to specific application requirements to adapt to different wavelength ranges and optical performance requirements; a multi-layer antireflection coating can be added to the surface of the fused quartz lens to further reduce the surface reflectivity and improve the light flux and system energy transmission efficiency; to meet ultra-high precision requirements, the surface of the fused quartz lens can adopt ion beam polishing or plasma chemical etching processes to further reduce the surface roughness and improve the imaging quality of the lens.

[0064] The height of the fiber optic mounting barrel 3 is 8.12 mm and the diameter is 32 mm; by precisely designing the height and diameter of the fiber optic mounting barrel 3, the requirements of the laser direct imaging LDI lithography system for the compact structure and high integration of optical components are met. The height of the fiber optic mounting barrel 3 is set to 8.12 mm, so that the overall lens group has a lower height profile, effectively reducing the overall size of the system and improving the miniaturization level of the lithography equipment.

[0065] A diameter of 32 mm ensures that the fiber optic mounting barrel 3 has sufficient mechanical strength and stability, while providing a reasonable installation space for internal three-dimensional adjustment mechanisms such as the ball head hexagon adjuster 2 and the fixing nut 8, ensuring the normal operation of the adjustment mechanism and its high-precision adjustment ability. Through reasonable structural dimension design, the optical axis alignment accuracy between the fiber laser and the double lens combination system is ensured, improving the collimation of the laser incident beam and the utilization rate of light energy.

[0066] This structural design comprehensively considers factors such as mechanical strength, space utilization, adjustment accuracy, and heat dissipation to ensure the efficient and stable operation of the fiber optic mounting barrel 3 in the laser direct imaging system.

[0067] The dimensions of the fiber optic mounting barrel 3 can be adjusted according to the design requirements of different specifications of fiber lasers or lithography systems. For example, the height can be changed to 6 mm or 10 mm, and the diameter can be adjusted to 28 mm or 36 mm to adapt to systems with different power levels and focal length requirements; heat sinks can be added to the outer surface of the fiber optic mounting barrel 3 or high-efficiency heat-conducting coatings can be applied to improve the heat dissipation efficiency of the laser during long-term operation and ensure the stability of the system.

[0068] The adjustment accuracy of the ball head hexagon adjuster 2 is ±5 microns; by adopting a high-precision ball head hexagon adjuster 2, micron-level adjustment of the optical fiber fixing seat 5 in the X, Y, and Z directions is achieved; the adjustment accuracy of the ball head hexagon adjuster 2 is controlled within the range of ±5 microns, ensuring extremely high resolution and repeatability during the adjustment process.

[0069] The adjuster 2 is manufactured by adopting a high-precision machining process. The clearance between the ball head part and the threaded bushing 7 is extremely small, ensuring stability and sensitivity during the adjustment process; during the adjustment process, by rotating the hexagon adjusting rod to drive the micro-displacement of the ball head part, the precise pushing and pulling effect on the fixing nut 8 is realized, thereby controlling the spatial position of the optical fiber fixing seat 5 and ensuring the optical axis alignment accuracy of the laser beam exit end.

[0070] The adjustment accuracy of ±5 microns meets the stringent requirements of the high-precision laser direct imaging lithography system for spot collimation, energy distribution uniformity, and beam shape stability, improving the overall exposure consistency and yield of the system.

[0071] The adjustment accuracy can be further optimized according to different system requirements, such as increased to ±2 microns or higher, to meet the application requirements of ultra-high-precision laser systems or the semiconductor processing field.

[0072] Exposure uniformity detection and correction. After the adjustment is completed, the illumination uniformity of the laser beam emitted by the fiber laser is detected by a detection device. When the uniformity does not meet the set standard, steps three and four are repeated until the exposure uniformity meets the requirements.

[0073] After the installation and three-dimensional adjustment of the fiber laser and the adjustment mirror group are completed in this embodiment, a special detection device is used to detect the illumination uniformity of the laser beam emitted by the fiber laser; the detection device can include devices such as a CCD camera, a optical power meter, or a laser intensity analyzer, to analyze the light intensity distribution and energy uniformity of the laser beam emitted in real time.

[0074] When the detection result shows that the beam uniformity does not reach the set target standard, the operator needs to re-execute step three (X and Y direction adjustment) and step four (Z direction adjustment) in the three-dimensional adjustment steps according to the detection feedback; by finely adjusting the ball head hexagon adjuster 2 and adjusting the height of the optical fiber fixing seat 5, the fine position correction of the laser beam exit end of the fiber laser is realized, optimizing the divergence angle and optical axis position of the beam.

[0075] This method ensures that the exposure uniformity is stably within the set standard range through a closed-loop calibration mechanism of cyclic detection and repeated adjustment, improving the exposure quality and pattern consistency of the lithography system.

[0076] The basic principles, main features and advantages of the present invention have been shown and described above. Without departing from the spirit and scope of the present invention, various changes and improvements are possible, and all such changes and improvements fall within the scope of the claimed invention.

Claims

1. A method for improving illumination uniformity, characterized in that: The invention relates to an adjustment lens group for improving illumination uniformity, the lens group comprising a first lens (9), a second lens (10), a lens barrel (11), an optical fiber fixing seat (5) and a three-dimensional adjustment mechanism, wherein the first lens (9) and the second lens (10) are respectively arranged in a lens seat (1), the lens seat (1) is arranged in the lens barrel (11), and the convex surfaces of the two lenses are arranged opposite to each other, an optical fiber installation lens barrel (3) is arranged at the upper end of the lens barrel (11), the optical fiber fixing seat (5) is installed in the optical fiber installation lens barrel (3), the three-dimensional adjustment mechanism is arranged between the optical fiber installation lens barrel (3) and the optical fiber fixing seat (5), the three-dimensional adjustment mechanism comprises a tightening nut (4), a fixing nut (8) and a ball head hexagonal adjuster (2), the fixing nut (8) is arranged in the optical fiber installation lens barrel (3), and the optical fiber fixing seat (5) is installed on the fixing nut (8), and the adjustment method comprises the following specific steps: Step 1: installing the optical lens assembly, wherein the first lens (9) and the second lens (10) are respectively installed in the lens holder (1), so that the first lens (9) and the second lens (10) are assembled in the lens barrel (11) through the lens holder (1) with their convex surfaces facing each other, thereby forming a double lens combination system; Step 2: Install the three-dimensional adjustment mechanism. Install the threaded bushing (7) into the optical fiber installation lens barrel (3), then install the ball head hexagonal adjuster (2) into the threaded bushing (7), fix the optical fiber installation lens barrel (3) to the lens barrel (11) with the connecting screw (12), install the optical fiber fixing seat (5) on the fixing nut (8), put the fixing nut (8) into the optical fiber installation lens barrel (3), tighten the fixing nut (8) with the ball head hexagonal adjuster (2), screw the tightening nut (4) into the optical fiber fixing seat (5), and then tighten the nut (6); Step 3: Adjust in the X and Y directions. Slightly loosen the ball head hexagonal adjuster (2) in one direction, and then tighten the ball head hexagonal adjuster (2) in the opposite direction. Use this method to adjust the eccentricity. Step 4: Adjustment in the Z direction: first, loosen the tightening nut (4) through the tightening nut adjustment hole (14) with a wrench, and then use the wrench to rotate and adjust the height of the optical fiber fixing seat (5) through the fixing seat adjustment hole (13); Step 5: Locking operation. After completing the three-dimensional adjustment, use the double nut structure to lock the Z-axis adjustment position. Use a wrench to tighten the tightening nut (4) through the tightening nut adjustment hole (14). Use the ball head hexagonal adjuster (2) to lock the adjustment position in the X and Y directions. After fixing its position, tighten the nut (6).

2. The method for improving illumination uniformity according to claim 1, characterized in that: A vertical convex groove (16) is provided in the circumferential direction of the lens holder (1), a limit slot (17) is provided at the bottom of the vertical convex groove (16), a fixing ring (20) is provided in the circumferential direction of the first lens (9) and the second lens (10), a connecting rib (18) is provided in the circumferential direction of the fixing ring (20), the first lens (9) and the second lens (10) are respectively clamped in the vertical convex groove (16) of the lens holder (1) through the connecting rib (18), a rubber block (19) is provided at the outer end of the connecting rib (18), and the rubber block (19) is rotatably clamped into the limit slot (17).

3. The method for improving illumination uniformity according to claim 1, characterized in that: An annular inner boss (15) is provided in the inner circumferential direction of the lens holder (1), and the bottom surfaces of the first lens (9) and the second lens (10) are respectively adhered to the annular inner boss (15) of the lens holder (1), and the first lens (9) and the second lens (10) are both plano-convex lenses.

4. The method for improving illumination uniformity according to claim 1, characterized in that: A bottom plate (21) is provided at the lower end of the optical fiber mounting lens barrel (3), a fixing nut (8) abuts against the bottom plate (21), the bottom plate (21) is pressed against the lens holder (1), a center hole (22) is provided at the center of the bottom plate (21), an upward protrusion is provided at the edge of the center hole (22), and the lower end of the optical fiber fixing seat (5) is located in the center hole (22).

5. The method for improving illumination uniformity according to claim 1, characterized in that: Adjustment holes (23) are evenly arranged in the circumferential direction of the side surface of the optical fiber installation lens barrel (3), at least four adjustment holes (23) are arranged, a threaded bushing (7) is arranged in the adjustment hole (23), and the ball head hexagonal adjuster (2) is screwed into the threaded bushing (7).

6. The method for improving illumination uniformity according to claim 1, characterized in that: The first lens (9) and the second lens (10) are made of fused quartz material.

7. The method for improving illumination uniformity according to claim 1, characterized in that: The fiber mounting barrel (3) has a height of 8.12 mm and a diameter of 32 mm.

8. The method for improving illumination uniformity according to claim 1, characterized in that: The adjustment accuracy of the ball head hexagonal adjuster (2) is ±5 microns.

9. The method for improving illumination uniformity according to claim 1, characterized in that: After the adjustment is completed, the illumination uniformity of the optical fiber laser output light beam is detected by a detection device. When the uniformity does not meet the set standard, steps three and four are repeated until the exposure uniformity meets the requirements.

10. The method for improving illumination uniformity according to claim 1, characterized in that: A threaded bushing (7) is provided in the circumferential direction of the optical fiber installation lens barrel (3), a ball head hexagonal adjuster (2) is installed in the threaded bushing (7), and the ball head end of the ball head hexagonal adjuster (2) corresponds to the fixing nut (8), a tightening nut (4) is provided on the optical fiber fixing seat (5), the tightening nut (4) and the fixing nut (8) constitute a locking mechanism, a tightening nut adjustment hole (14) is provided on the tightening nut (4), a fixing seat adjustment hole (13) is provided on the optical fiber fixing seat (5), and a nut (6) is provided above the optical fiber installation lens barrel (3).

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