Maskless exposure system

Abstract

The utility model provides a maskless exposure system which is characterized in that in the maskless exposure system, a beam expander is used for expanding a light beam emitted by an ultraviolet laser light source to form an exposure field with uniformly distributed light intensity; the polarizer processes the exposure field to form linearly polarized light; the linearly polarized light is modulated by a liquid crystal spatial light modulator to form parallel light which is uniformly distributed; the digital microlens array processes the phase and the amplitude of the parallel light, so that the processed parallel light forms a to-be-exposed pattern on the wafer surface of the wafer workpiece table; the control unit controls the wafer stage to move so as to expose the wafer. According to the exposure mode, the digital pattern to be exposed can be directly transmitted to the photoresist on the surface of the wafer without a mask plate, an infinite exposure area can be realized through the movement of the wafer workpiece table, the exposure efficiency and the exposure precision are improved, and the digital micro lens unit is adopted to replace a traditional shaping light path, so that the system structure is simplified.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor processing and manufacturing, in particular to a maskless exposure system. Background Art

[0002] Photolithography is one of the indispensable key technologies in the field of semiconductor processing and manufacturing technology, and exposure is a key step in photolithography. In the past, photolithography methods required the use of masks to shield light, so that the corresponding pattern was projected onto the photoresist layer to form the desired pattern. This method requires the preparation of masks, which is costly. At the same time, due to factors such as the mechanical properties of the mask material and the manufacturing process, the service life of the mask is difficult to predict, and the size of the mask is also subject to certain limitations. In addition, in micro-nano processing and multi-layer preparation, the alignment error and alignment accuracy of the mask will also have a negative impact on device performance. In recent years, with the increasing requirements for semiconductor manufacturing products, the requirements for the development of exposure have also become higher and higher. With the development of technologies such as digital micro-nano processing and manufacturing, maskless lithography has gradually become one of the research hotspots.

[0003] Among them, maskless lithography is a method of transferring digital optical pattern information directly to the photoresist layer in some way. This lithography method avoids the cumbersome process step of using a mask and greatly improves the efficiency and precision of the processing technology. However, existing maskless lithography methods such as laser direct writing lithography and reflective maskless lithography have certain problems, such as low processing efficiency, low precision and high equipment cost, which cannot meet the actual application needs. Utility Model Content

[0004] In view of this, the purpose of the utility model is to provide a maskless exposure system to alleviate the above-mentioned problems. The digitized pattern to be exposed can be directly transferred to the photoresist on the surface of the wafer without a mask, and an infinite exposure area can be achieved through the movement of the wafer workpiece stage, thereby improving the exposure efficiency and exposure accuracy. The digital microlens unit is used to replace the traditional shaping light path, thereby simplifying the system structure.

[0005] In a first aspect, an embodiment of the utility model provides a maskless exposure system, which includes: an ultraviolet laser light source, a beam expander, a digital microlens unit, a polarizer, a wafer worktable and a control unit; wherein the digital microlens unit includes a digital microlens array and a liquid crystal spatial light modulator, and the polarizer is arranged between the beam expander and the liquid crystal spatial light modulator;

[0006] The beam expander is used to expand the light beam emitted by the ultraviolet laser light source to form an exposure field with uniform light intensity distribution;

[0007] The polarizer is used to process the exposure field to form linearly polarized light;

[0008] The liquid crystal spatial light modulator is used to modulate the linearly polarized light to form evenly distributed parallel light;

[0009] The digital microlens array is used to process the phase and amplitude of the parallel light so that the processed parallel light forms a pattern to be exposed on the wafer surface of the wafer worktable;

[0010] The control unit is used to control the movement of the wafer worktable to expose the wafer.

[0011] Preferably, the system further comprises a distance detection unit;

[0012] The distance detection unit is used to detect the vertical distance between the digital microlens array and the wafer plane, and send the vertical distance to the control unit;

[0013] The control unit is further used to adjust the position of the digital microlens array and / or the wafer plane according to the vertical distance, so that the wafer plane is located in the focal plane of the digital microlens array.

[0014] Preferably, the wafer plane is divided into a plurality of grid units of rectangular areas; wherein the size of each of the grid units is the same; the pattern to be exposed includes a plurality of sub-patterns to be exposed, and the size of each sub-pattern to be exposed is consistent with the rectangular area of ​​the corresponding grid unit.

[0015] Preferably, the pattern to be exposed further comprises a plurality of slit sub-patterns to be exposed, and the size of each of the slit sub-patterns to be exposed is consistent with the width of the corresponding rectangular area of ​​the grid unit.

[0016] Preferably, the digital microlens array comprises a plurality of microlenses, and the plurality of microlenses are arranged according to a preset rule.

[0017] Preferably, a plurality of the microlenses form a multi-layer microlens array.

[0018] Preferably, the wafer worktable comprises: an XY motion table, a Z-axis wafer chuck, a vacuum suction cup and a pneumatic cylinder; wherein the vacuum suction cup is installed on the XY motion table, the Z-axis wafer chuck is clamped on the periphery of the wafer, and the pneumatic cylinder is used to adsorb the wafer on the vacuum suction cup.

[0019] Preferably, the system further comprises a driving unit for driving the XY motion stage to move.

[0020] Preferably, the control unit is further used to control the driving unit to drive the XY motion stage to perform stepping motion or stepping scanning motion.

[0021] Preferably, the Z-axis wafer chuck has a rotation axis, and the control unit is further used to control the driving unit to drive the Z-axis wafer chuck to rotate around the rotation axis to perform rotational exposure on the wafer.

[0022] In a second aspect, an embodiment of the present invention further provides a maskless exposure method, which is applied to the maskless exposure system of the first aspect, and the method comprises:

[0023] Controlling the ultraviolet laser light source to emit a light beam, and controlling the beam expander to perform beam expansion processing on the light beam to form an exposure field with uniform light intensity distribution;

[0024] Controlling the polarizer to process the exposure field to form linearly polarized light, and controlling the liquid crystal spatial light modulator to modulate the linearly polarized light to form evenly distributed parallel light;

[0025] Controlling the digital microlens array to process the phase and amplitude of the parallel light, so that the processed parallel light forms a pattern to be exposed on the wafer surface of the wafer worktable;

[0026] The wafer worktable is controlled to move so as to expose the wafer.

[0027] The embodiments of the present invention bring the following beneficial effects:

[0028] The embodiment of the utility model provides a maskless exposure system, which can directly transfer a digitized pattern to be exposed to the photoresist on the surface of a wafer without a mask, and can achieve an infinite exposure area through the movement of the wafer workpiece stage, thereby improving exposure efficiency and exposure accuracy. A digital microlens unit is used to replace the traditional shaping light path, which simplifies the system structure and reduces the cost of exposure equipment.

[0029] Other features and advantages of the utility model will be described in the following description, and partly become apparent from the description, or understood by practicing the utility model. The purpose and other advantages of the utility model are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 A structural schematic diagram of a maskless exposure system provided by an embodiment of the utility model;

[0033] Figure 2 A schematic diagram of parallel light reaching a digital microlens array provided by an embodiment of the utility model;

[0034] Figure 3 A schematic diagram of a wafer workpiece stage according to a serpentine motion provided by an embodiment of the utility model;

[0035] Figure 4 A schematic diagram of a wafer workpiece stage step-scan motion provided by an embodiment of the utility model;

[0036] Figure 5 A flowchart of a maskless exposure method provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the technical solution of the utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0038] To facilitate understanding of this embodiment, the embodiment of the utility model is described in detail below.

[0039] Embodiment 1:

[0040] The utility model embodiment provides a maskless exposure system, such as Figure 1 As shown, the system includes: an ultraviolet laser light source 11, a beam expander 12, a digital microlens unit, a polarizer (not shown), a wafer worktable (not shown) and a control unit (not shown); wherein the digital microlens unit includes a digital microlens array 13 and a liquid crystal spatial light modulator (not shown), the polarizer is arranged between the beam expander 12 and the liquid crystal spatial light modulator, and the wafer worktable is used to mount a wafer 14.

[0041] Specifically, the ultraviolet laser light source 11 is used as a lithography light source to emit a light beam, and the beam expander 12 is used to expand the light beam to form an exposure field with uniform light intensity distribution. In practical applications, the ultraviolet laser light source 11 is an all-solid-state ultraviolet laser light source with good collimation. The ultraviolet laser light source 11 and the beam expander 12 are used to replace the complex light source collimation optical path in the lithography machine exposure system, thereby simplifying the system structure and saving the cost of lithography equipment.

[0042] The above-mentioned exposure field reaches the polarizer, at which time, the polarizer processes the exposure field to form linearly polarized light; the liquid crystal spatial light modulator modulates the linearly polarized light to form evenly distributed parallel light; specifically, the liquid crystal spatial light modulator can achieve precise control of the refractive index distribution under the action of the electric field, thereby achieving simultaneous control of the amplitude and phase of the light wave to form evenly distributed parallel light.

[0043] In addition, if Figure 2 As shown, the parallel light reaches the digital microlens array 13, and the digital microlens array 13 processes the phase and amplitude of the parallel light so that the processed parallel light forms a pattern to be exposed on the surface of the wafer 14 of the wafer worktable; therefore, the light beam emitted by the ultraviolet laser light source 11 is irradiated onto the digital microlens array 13 after being processed by the beam expander 12, the polarizer, and the liquid crystal spatial light modulator, and forms a pattern to be exposed on the surface of the wafer 14 after being processed by the digital microlens array 13. Here, the pattern to be exposed refers to a pre-designed integrated circuit or a plane grating design drawing, etc., so that the digital microlens array 13 replaces the shaping light path, and the pattern to be exposed can be formed directly through the digital microlens array 13 without the need for a traditional mask, making the optical system simple and efficient.

[0044] And, the wafer 14 refers to a silicon wafer used to make silicon semiconductor integrated circuits. Photoresist is coated on the wafer 14, and pattern transfer can be achieved through exposure. For example, the pattern to be exposed is fixed on the wafer 14, which can be used to make various circuit element structures. Here, after the pattern to be exposed reaches the surface of the wafer 14, during exposure, the control unit controls the movement of the wafer worktable to expose the entire wafer 14 until the pattern to be exposed is transferred to the wafer 14.

[0045] Therefore, the above-mentioned maskless exposure system does not require a mask plate, which simplifies the structure of the exposure system. At the same time, there is no need for the alignment step between the mask and the wafer. The digitized pattern to be exposed can be directly transferred to the photoresist on the surface of the wafer, thereby improving the exposure efficiency. In addition, an infinite exposure area can be achieved through the movement of the wafer worktable, thereby improving the exposure efficiency and exposure accuracy.

[0046] By way of example, the system also includes a distance detection unit (not shown); used to detect the vertical distance between the digital microlens array 13 and the plane of the wafer 14, and send the vertical distance to the control unit; the control unit is also used to adjust the position of the digital microlens array 13 and / or the plane of the wafer 14 according to the vertical distance, so that the plane of the wafer 14 is in the focal plane of the digital microlens array 13.

[0047] Therefore, by always keeping the plane of the wafer 14 at the focal plane of the digital microlens array 13, the pattern to be exposed can be completely fixed on the plane of the wafer 14, thereby improving the exposure accuracy.

[0048] For example, the digital microlens array 13 includes a plurality of microlenses, and the plurality of microlenses are arranged according to a preset rule. Figure 1 As shown, the digital microlens array 13 is composed of a series of tiny lenses (i.e., microlenses) arranged in a certain pattern. Each microlens can independently adjust the phase and amplitude of the incident light, thereby achieving simultaneous control of the angle and intensity distribution of the incident light. During the exposure process, by adjusting the phase and amplitude of the incident light on each microlens on the digital microlens array 13, the light is only irradiated to the position corresponding to the pattern to be exposed, thereby achieving maskless exposure.

[0049] In addition, by adjusting the phase and amplitude of the incident light on each microlens, the exposure spot size can be adjusted and the exposure time can be precisely controlled; wherein, the exposure time refers to the exposure time required for lithography on the wafer 14. The length of the exposure time determines the depth and quality of the lithography, and is also one of the most core parameters in the lithography process. Therefore, the maskless exposure system provided in the embodiment of the utility model, in order to achieve the desired processing effect, also improves the exposure accuracy and exposure efficiency by precisely controlling the exposure time.

[0050] Preferably, a plurality of microlenses form a multi-layer microlens array, that is, the digital microlens array 13 includes a multi-layer microlens array, each layer of the microlens array includes a plurality of microlenses, and a higher resolution and more complex pattern to be exposed can be formed through the multi-layer microlens array, thereby meeting the application requirements of various photolithography scenarios. It should be noted that the pattern to be exposed can be generated according to actual needs through computer-aided design software and loaded on the digital microlens array 13, so that the digital microlens array 13 processes the phase and amplitude of the parallel light to form a corresponding pattern to be exposed.

[0051] In practical applications, the digital microlens array 13 can use adaptive optical technology to achieve real-time fine-tuning of focal length and depth of focus, thereby achieving higher exposure accuracy and wider depth of focus. Specifically, adaptive optical technology utilizes the characteristics that each microlens in the digital microlens array 13 can adjust the phase and amplitude of the light path to achieve real-time focal length adjustment; for example, the control unit can adjust the phase and amplitude of each microlens by transmitting a control electrical signal to the digital microlens array 13, thereby changing the focus position of the light and achieving real-time fine-tuning of the focal length.

[0052] At the same time, adaptive optics can also achieve a wider depth of focus by fine-tuning the phase and amplitude of the optical path. When the focal length remains unchanged, by adjusting the bias and amplitude of each microlens, the aggregation effect of light near the focus can be increased, thereby achieving a wider depth of focus. In addition, adaptive optics can also accurately adjust the phase and amplitude of each microlens by real-time monitoring of the exposure effect, thereby improving exposure accuracy.

[0053] For example, the wafer workpiece table includes: an XY motion table, a Z-axis wafer chuck, a vacuum suction cup and a pneumatic cylinder; wherein the vacuum suction cup is installed on the XY motion table, the Z-axis wafer chuck is clamped on the periphery of the wafer 14, and the pneumatic cylinder is used to adsorb the wafer 14 on the vacuum suction cup.

[0054] Specifically, the XY motion stage is used to move in the XY plane to adjust the X coordinate and Y coordinate of the wafer 14. In addition, the system also includes a driving unit for driving the XY motion stage to move. In actual applications, the control unit controls the driving unit to drive the XY motion stage to perform stepping motion or step-scanning motion to drive the wafer 14 adsorbed thereon to move.

[0055] It should be noted that the driving unit may be a driving servo motor or other structures. The embodiments of the utility model do not limit the specific composition of the driving unit and the driving method of the driving unit to drive the XY motion table to move in the XY plane.

[0056] In addition, the Z-axis wafer chuck also has a high-resolution rotation axis for adjusting the rotation angle of the wafer 14. Specifically, the control unit controls the driving unit to drive the Z-axis wafer chuck to rotate around the rotation axis to perform rotational exposure on the wafer 14, thereby achieving more complex exposure patterns and higher production efficiency.

[0057] Furthermore, when the control unit controls the maskless exposure system, a closed-loop control system is used to achieve real-time adjustment and correction of the wafer position, light source intensity, parameters of the digital microlens array 13, etc., so as to improve the exposure effect and exposure accuracy. For example, when the control system receives the beam signal of the ultraviolet laser light source 11, the drive unit is controlled to control the movement of the wafer worktable. In addition, the control system can also control the opening and closing of the ultraviolet laser light source 11 and the size of the light intensity, thereby improving the exposure accuracy and exposure efficiency.

[0058] For example, the wafer plane is divided into a plurality of grid units of rectangular areas, wherein the size of each grid unit is the same; the pattern to be exposed includes a plurality of sub-patterns to be exposed, and the size of each sub-pattern to be exposed is consistent with the rectangular area of ​​the corresponding grid unit.

[0059] Specifically, the surface of the wafer 14 is divided into a plurality of grid units of rectangular areas of the same size, and the size of each grid unit is specifically divided according to the exposure requirements; then, the control unit controls the movement of the wafer worktable, such as moving in a serpentine manner, and sequentially exposes each grid unit along the serpentine route to transmit the pattern to be exposed. Figure 3 As shown, 1 to 14 represent fourteen grid units respectively, and the direction of the arrow represents the direction of the stepping movement. The grid units 1 to 14 are exposed in sequence in a serpentine route, thereby realizing exposure of a large exposure area.

[0060] In the exposure process of the entire wafer 14, one method can be to use a grid unit as an exposure sub-area, and form a sub-pattern to be exposed corresponding to each exposure sub-area through the digital microlens array 13. At this time, the pattern to be exposed includes multiple sub-patterns to be exposed, and the size of each sub-pattern to be exposed is consistent with the rectangular area of ​​the corresponding grid unit. The sub-pattern to be exposed corresponding to each exposure sub-area is transferred to the wafer 14 through exposure, and finally, the sub-pattern to be exposed corresponding to each exposure sub-area is spliced ​​to form a complete exposure pattern. Therefore, this method can realize the production of a large-area exposure pattern by splicing the sub-patterns to be exposed of each exposure sub-area.

[0061] In addition, in the exposure process of the entire wafer 14, another method can be to use a grid unit as an exposure sub-area, and form a slit sub-pattern to be exposed corresponding to the width of each exposure sub-area through the digital microlens array 13. At this time, the pattern to be exposed also includes multiple slit sub-patterns to be exposed, and the size of each slit sub-pattern to be exposed is consistent with the width of the rectangular area of ​​the corresponding grid unit. At this time, the slit sub-pattern to be exposed corresponding to each exposure sub-area is transferred to the wafer 14 through scanning exposure in turn, and finally, the slit sub-pattern to be exposed corresponding to each exposure sub-area is spliced ​​to form a complete pattern.

[0062] like Figure 4 As shown in the figure, the shaded area 41 is the slit sub-pattern to be exposed, the non-shaded area 42 is an exposure sub-area, and the arrow indicates the scanning direction of the wafer worktable. Therefore, this method can realize the production of a large-area exposure pattern by splicing the slit sub-patterns to be exposed in each exposure sub-area.

[0063] It should be noted that, since the maskless step-and-scan exposure method can be applied to forming periodic patterns on the surface of the wafer 14, the above-mentioned maskless step-and-scan exposure method can also be used to produce plane gratings, especially large-area plane gratings, thereby meeting the needs of various application scenarios.

[0064] In summary, the mask exposure system provided by the embodiment of the utility model replaces the traditional mask plate by passing the light beam emitted by the ultraviolet laser light source 11 through the digital microlens array 13 to form the pattern to be exposed, so that the maskless exposure method is more flexible and simple, and the exposure efficiency is improved. In addition, the digital microlens array 13 is used to replace the shaping light path, making the optical system simple and efficient, and reducing the cost of the exposure equipment; at the same time, by controlling the stepping or stepping scanning movement of the wafer worktable, an infinite exposure area can be achieved, which improves the exposure efficiency and exposure accuracy.

[0065] Embodiment 2:

[0066] Based on the above-mentioned maskless exposure system, the embodiment of the utility model further provides a maskless exposure method, the execution subject is a control unit, such as Figure 5 As shown, the method comprises the following steps:

[0067] Step S502, controlling the ultraviolet laser light source to emit a light beam, and controlling the beam expander to expand the light beam to form an exposure field with uniform light intensity distribution;

[0068] Step S504, controlling the polarizer to process the exposure field to form linearly polarized light, and controlling the liquid crystal spatial light modulator to modulate the linearly polarized light to form evenly distributed parallel light;

[0069] Step S506, controlling the digital microlens array to process the phase and amplitude of the parallel light, so that the processed parallel light forms a pattern to be exposed on the wafer surface of the wafer worktable;

[0070] Step S508, controlling the movement of the wafer worktable to expose the wafer.

[0071] During the exposure process, first, the wafer surface is divided into multiple grid units of rectangular areas of the same size. Then, the control unit controls the stepping movement or step-scanning movement of the wafer worktable to expose each grid unit in turn and transfer the pattern to be exposed.

[0072] In one exposure method, a grid unit is used as an exposure sub-area, and a sub-pattern to be exposed corresponding to each exposure sub-area is formed through a digital microlens array. At this time, the pattern to be exposed includes multiple sub-patterns to be exposed, and the size of each sub-pattern to be exposed is consistent with the rectangular area of ​​the corresponding grid unit. The sub-pattern to be exposed corresponding to each exposure sub-area is transferred to the wafer through exposure, and finally, the sub-pattern to be exposed corresponding to each exposure sub-area is spliced ​​to form a complete exposure pattern.

[0073] Another exposure method is to use a grid unit as an exposure sub-area, and form a slit sub-pattern to be exposed corresponding to the width of each exposure sub-area through a digital microlens array. At this time, the pattern to be exposed also includes multiple slit sub-patterns to be exposed, and the size of each slit sub-pattern to be exposed is consistent with the width of the rectangular area of ​​the corresponding grid unit. At this time, the slit sub-pattern to be exposed corresponding to each exposure sub-area is transferred to the wafer through scanning exposure in turn, and finally, the slit sub-pattern to be exposed corresponding to each exposure sub-area is spliced ​​to form a complete pattern.

[0074] It should be noted that the selection of a specific exposure method and the sub-pattern to be exposed corresponding to each grid unit can be set according to actual conditions, and the process of each step in the above method can refer to the aforementioned system embodiment, and the embodiment of the utility model will not be described in detail here.

[0075] The maskless exposure method provided by the embodiment of the utility model can directly transfer the digitized pattern to be exposed to the photoresist on the surface of the wafer without the need for a mask, and can achieve an infinite exposure area through the movement of the wafer workpiece stage, thereby improving the exposure efficiency and exposure accuracy. In addition, a digital microlens unit is used to replace the traditional shaping light path, thereby simplifying the system structure and reducing the cost of the exposure equipment.

[0076] The maskless exposure method provided in the embodiment of the utility model has the same technical features as the maskless exposure device provided in the above embodiment, so it can also solve the same technical problems and achieve the same technical effects.

[0077] The device provided in the embodiment of the utility model can be specific hardware on the device or software or firmware installed on the device. The implementation principle and technical effects of the device provided in the embodiment of the utility model are the same as those of the aforementioned method embodiment. For the sake of brief description, the parts not mentioned in the device embodiment can refer to the corresponding contents in the aforementioned method embodiment. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, devices and units described above can all refer to the corresponding processes in the aforementioned method embodiment, and will not be repeated here.

[0078] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0079] In addition, each functional unit in the embodiment provided by the present utility model may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0080] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that can be executed by a processor. Based on this understanding, the technical solution of the utility model, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the utility model. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program code.

[0081] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0082] Furthermore, the terms “first”, “second”, and “third” are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0083] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the utility model, which are used to illustrate the technical solution of the utility model, rather than to limit it. The protection scope of the utility model is not limited thereto. Although the utility model is described in detail with reference to the above-mentioned embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solution recorded in the above-mentioned embodiments within the technical scope disclosed by the utility model, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solution of the embodiment of the utility model, and should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A maskless exposure system, characterized in that: The system comprises: an ultraviolet laser light source, a beam expander, a digital microlens unit, a polarizer, a wafer worktable and a control unit; wherein the digital microlens unit comprises a digital microlens array and a liquid crystal spatial light modulator, and the polarizer is arranged between the beam expander and the liquid crystal spatial light modulator; The beam expander is used to expand the light beam emitted by the ultraviolet laser light source to form an exposure field with uniform light intensity distribution; The polarizer is used to process the exposure field to form linearly polarized light; The liquid crystal spatial light modulator is used to modulate the linearly polarized light to form evenly distributed parallel light; The digital microlens array is used to process the phase and amplitude of the parallel light so that the processed parallel light forms a pattern to be exposed on the wafer surface of the wafer worktable; The control unit is used to control the movement of the wafer worktable to expose the wafer.

2. The maskless exposure system according to claim 1, characterized in that: The system also includes a distance detection unit; The distance detection unit is used to detect the vertical distance between the digital microlens array and the wafer plane, and send the vertical distance to the control unit; The control unit is further used to adjust the position of the digital microlens array and / or the wafer plane according to the vertical distance, so that the wafer plane is located in the focal plane of the digital microlens array.

3. The maskless exposure system according to claim 2, characterized in that: The wafer plane is divided into a plurality of grid units of rectangular areas; wherein the size of each of the grid units is the same; the pattern to be exposed includes a plurality of sub-patterns to be exposed, and the size of each sub-pattern to be exposed is consistent with the rectangular area of ​​the corresponding grid unit.

4. The maskless exposure system according to claim 3, characterized in that: The pattern to be exposed further includes a plurality of slit sub-patterns to be exposed, and the size of each of the slit sub-patterns to be exposed is consistent with the width of the corresponding rectangular area of ​​the grid unit.

5. The maskless exposure system according to claim 1, characterized in that: The digital microlens array includes a plurality of microlenses, and the plurality of microlenses are arranged according to a preset rule.

6. The maskless exposure system according to claim 5, characterized in that: A plurality of the microlenses form a multi-layer microlens array.

7. The maskless exposure system according to claim 1, characterized in that: The wafer worktable includes: an XY motion table, a Z-axis wafer chuck, a vacuum suction cup and a pneumatic cylinder; wherein the vacuum suction cup is installed on the XY motion table, the Z-axis wafer chuck is clamped on the periphery of the wafer, and the pneumatic cylinder is used to adsorb the wafer on the vacuum suction cup.

8. The maskless exposure system according to claim 7, characterized in that: The system further comprises a driving unit for driving the XY motion stage to move.

9. The maskless exposure system according to claim 8, characterized in that: The control unit is further used to control the driving unit to drive the XY motion stage to perform stepping motion or stepping scanning motion.

10. The maskless exposure system according to claim 8, characterized in that: The Z-axis wafer chuck has a rotation axis, and the control unit is further used to control the driving unit to drive the Z-axis wafer chuck to rotate around the rotation axis to perform rotational exposure on the wafer.

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