Projection exposure system and method for controlling the same

Abstract

The application provides a projection exposure system and a control method thereof. The projection exposure system comprises: a light source, a liquid crystal switch panel, a liquid crystal phase retarder and a phase retardation wave plate arranged in sequence along a first direction; the liquid crystal switch panel comprises a plurality of arrayed liquid crystal micro-area switches for converting a light beam into first linearly polarized light and controlling whether the first linearly polarized light passes; the liquid crystal phase retarder is used for generating respective phase delays of a vertical component and a parallel component of the first linearly polarized light, so that the vertical component and the parallel component have a designed phase difference; and the phase retardation wave plate is used for generating a phase delay of light output by the liquid crystal phase retarder to obtain and output second linearly polarized light, and an azimuth angle of the second linearly polarized light has a corresponding relationship with the designed phase difference. By using the application, liquid crystal orientation micro-area control can be realized in a large area, high efficiency and high precision without expensive mask costs, and the application has the advantages of low cost, real-time control and tuning.

Description

Technical Field

[0001] This application relates to the field of optical technology, and more specifically, to a projection exposure system and its control method. Background Technology

[0002] Liquid crystals are high-performance optical materials that are currently widely used in the display field. In non-display applications, liquid crystal materials also have broad prospects; optical components such as liquid crystal lenses, liquid crystal gratings, and liquid crystal structured light field slides are extensively studied and applied in fields such as optical communication, laser processing, and particle manipulation.

[0003] In order to utilize the unique optical anisotropy and birefringence properties of liquid crystals, it is necessary to align the liquid crystal molecules in a certain orientation, and thus liquid crystal alignment technology came into being.

[0004] Traditional photo-alignment uses a cloth to rub a polymer film, creating small grooves to align liquid crystal molecules. Photo-alignment is a novel liquid crystal alignment method. Under the influence of linearly polarized light, a direction-selective photochemical reaction occurs on the polymer surface, causing anisotropic distribution of polymer molecules. When liquid crystal molecules come into contact with this surface, they tend to align with the polymer molecules due to intermolecular interactions. Compared to traditional rubbing alignment, photo-alignment is non-contact, static-free, pollution-free, damage-free, and rewritable, making it widely applicable.

[0005] Common optical orientation methods include laser direct writing and mask exposure. However, laser direct writing uses a point-by-point scanning method for optical orientation, which is very inefficient; mask exposure requires additional masks for optical orientation, resulting in higher manufacturing costs, and when there are many optical orientation directions, a large number of masks are also required. Summary of the Invention

[0006] This application addresses the shortcomings of existing methods by proposing a projection exposure system and its control method to solve the technical problems of low efficiency in light-controlled orientation due to point-by-point scanning or high cost due to the need for masks in existing technologies.

[0007] In a first aspect, embodiments of this application provide a projection exposure system, comprising: a light source, a liquid crystal switch panel, a liquid crystal phase delayer, and a phase delay waveplate arranged sequentially along a first direction;

[0008] A light source used to output a beam of light;

[0009] The liquid crystal switch panel includes multiple arrayed liquid crystal micro-switches for converting a light beam into first linearly polarized light and controlling whether the first linearly polarized light passes through.

[0010] A liquid crystal phase retarder is used to generate phase delays for the vertical and parallel components of a first linearly polarized light, so that the vertical and parallel components have a designed phase difference.

[0011] A phase delay waveplate is used to delay the phase of the light output from a liquid crystal phase delayer, thereby obtaining and outputting a second linearly polarized light. The azimuth angle of the second linearly polarized light corresponds to the designed phase difference.

[0012] Secondly, embodiments of this application provide a control method for a projection exposure system, applied to the projection exposure system as described in the first aspect, the control method comprising:

[0013] The liquid crystal micro-switches in the corresponding light-transmitting area of ​​the liquid crystal switch panel are turned on to allow the first linearly polarized light to pass through, while all remaining liquid crystal micro-switches are turned off. The light-transmitting area is an exposure pattern corresponding to the light-controlled alignment substrate to be exposed, and the exposure pattern includes at least one pattern unit of the same light-controlled alignment.

[0014] The liquid crystal phase retarder is controlled to generate phase delays for the vertical and parallel components of the first linearly polarized light, so that the vertical and parallel components have a designed phase difference. After phase delay by the phase retardation waveplate, the second linearly polarized light is obtained and output. The azimuth angle of the second linearly polarized light corresponds to the designed phase difference, so that the liquid crystal in the light-controlled alignment substrate in the light-transmitting area forms an alignment arrangement consistent with the azimuth angle of the second linearly polarized light.

[0015] The beneficial technical effects of the technical solutions provided in this application include:

[0016] The projection exposure system provided in this application, by setting a light source, a liquid crystal switch panel, a liquid crystal phase retarder, and a phase retardation plate, allows the azimuth angle of the output linearly polarized light to change with the designed phase difference generated by the liquid crystal phase retarder. This enables the output of linearly polarized light with an arbitrary and flexible azimuth angle. Since the photo-alignment substrate is made of a photo-alignment material, the angle of molecular alignment of the material is strictly related to the azimuth angle (i.e., polarization direction) of the linearly polarized light. Therefore, the angle of molecular alignment of the photo-alignment substrate can be controlled by the azimuth angle of the linearly polarized light, thereby controlling the orientation of the liquid crystal molecules on the substrate. This allows for the fabrication of various liquid crystal optical elements with different functions. Therefore, by controlling the phase difference of the liquid crystal phase retarder, and thus controlling the azimuth angle of the output linearly polarized light, the orientation arrangement of liquid crystal molecules in an exposure pattern on the photo-alignment substrate can be controlled. This application achieves real-time control and fabrication of exposure patterns with arbitrary light-controlled orientation by controlling the phase difference of the liquid crystal phase retarder, enabling precise control of the polarization orientation of a small region of liquid crystal on a light-controlled alignment substrate, and enabling precise control of the polarization angle of the output linearly polarized light over a large area, pixel-level micro-region (the smallest pixel size of the exposure pattern, i.e., a pattern unit). This allows for free and flexible adjustment of the polarization angle within a pixel-level micro-region in light-controlled alignment or other semiconductor lithography scenarios, and can be applied to the fabrication of liquid crystal optical elements with complex light-controlled orientation exposure patterns.

[0017] Compared to other photo-controlled alignment schemes, the projection exposure system provided in this embodiment eliminates the need for expensive masks and simplifies the processing flow. It enables large-area, high-efficiency, and high-precision micro-area control of liquid crystal alignment, offering advantages such as low cost and real-time controllability and tuning. This is of great significance for liquid crystal applications in both display and non-display fields. Furthermore, it also has broad application potential in semiconductor polarization-related photolithography scenarios.

[0018] Moreover, the projection exposure system provided in this application embodiment can provide linearly polarized light at a specific azimuth angle as needed, and can be widely used in other exposure application scenarios.

[0019] Additional aspects and advantages of this application will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of this application. Attached Figure Description

[0020] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0021] Figure 1 A schematic diagram of the structure and optical path of a projection exposure system provided in this application embodiment;

[0022] Figure 2A schematic diagram of the polarization-related angles of various optical elements in a projection exposure system provided in this application embodiment;

[0023] Figure 3 This is a schematic diagram of the structure of a liquid crystal micro-zone switch provided in an embodiment of this application;

[0024] Figure 4 This is a schematic diagram of a liquid crystal phase delay device provided in an embodiment of this application;

[0025] Figure 5 A liquid crystal alignment arrangement for a liquid crystal polarization grating provided in an embodiment of this application;

[0026] Figure 6 This application provides a liquid crystal alignment distribution pattern for a single exposure of a liquid crystal polarization grating;

[0027] Figure 7 This application provides a liquid crystal alignment distribution pattern obtained by multiple exposures of a liquid crystal polarization grating.

[0028] Figure label:

[0029] 1-Light source;

[0030] 2-Beam expander;

[0031] 3-Liquid crystal switch panel, 301-First polarizer, 302-First substrate, 303-First control circuit, 304-Switch circuit, 305-First electrode, 306-Protective layer, 307-First alignment layer, 308-First sealant, 309-First spacer, 310-First liquid crystal layer, 311-Second alignment layer, 312-Second electrode, 313-Second substrate, 314-Second polarizer;

[0032] 4-Liquid crystal phase delay, 401-Third substrate, 402-Second control circuit, 403-Third electrode, 404-Third alignment layer, 405-Second sealant, 406-Second spacer, 407-Second liquid crystal layer, 408-Fourth alignment layer, 409-Fourth electrode, 410-Fourth substrate;

[0033] 5-Phase delay waveplate;

[0034] 6-Focusing lens;

[0035] 7-First Computer;

[0036] 8-Second computer;

[0037] 9-Optimized substrate;

[0038] 10-Displacement platform. Detailed Implementation

[0039] This application is described in detail below. Examples of embodiments of this application are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. Furthermore, detailed descriptions of known technologies that are unnecessary for the features of this application are omitted. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0040] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0041] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this application means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or wireless coupling. The term “and / or” as used herein includes all or any units and all combinations of one or more associated listed items.

[0042] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments.

[0043] This application provides a projection exposure system, such as... Figure 1 As shown, the projection exposure system includes: a light source 1, a liquid crystal switch panel 3, a liquid crystal phase retarder 4, and a phase retardation plate 5 arranged sequentially along a first direction; the first direction is the direction of light propagation (e.g., ...). Figure 1 (The direction of the arrow).

[0044] Light source 1, used to output a light beam.

[0045] The liquid crystal switch panel 3 includes multiple arrayed liquid crystal micro-switches for converting the light beam into first linearly polarized light and controlling whether the first linearly polarized light passes through.

[0046] The liquid crystal phase retarder 4 is used to generate phase delays for the vertical and parallel components of the first linearly polarized light (the light vector on the liquid crystal phase retarder 4), so that the vertical and parallel components have a designed phase difference.

[0047] The phase delay waveplate 5 is used to delay the phase of the light output from the liquid crystal phase delayer 4, and to obtain and output a second linearly polarized light. The azimuth angle of the second linearly polarized light has a corresponding relationship with the designed phase difference.

[0048] The projection exposure system provided in this application, by setting a light source, a liquid crystal switch panel, a liquid crystal phase retarder, and a phase retardation plate, allows the azimuth angle of the output linearly polarized light to change with the designed phase difference generated by the liquid crystal phase retarder. This enables the output of linearly polarized light with an arbitrary and flexible azimuth angle. Since the photo-alignment substrate is made of a photo-alignment material, the angle of molecular alignment of the material is strictly related to the azimuth angle (i.e., polarization direction) of the linearly polarized light. Therefore, the angle of molecular alignment of the photo-alignment substrate can be controlled by the azimuth angle of the linearly polarized light, thereby controlling the orientation of the liquid crystal molecules on the photo-alignment substrate. This allows for the fabrication of various liquid crystal optical elements with different functions. Therefore, by controlling the phase difference of the liquid crystal phase retarder, and thus controlling the azimuth angle of the output second linearly polarized light, the orientation arrangement of liquid crystal molecules in an exposure pattern on the photo-alignment substrate can be controlled. This application achieves real-time control and fabrication of exposure patterns with arbitrary light-controlled orientation by controlling the phase difference of the liquid crystal phase retarder, enabling precise control of the polarization orientation of a small region of liquid crystal on a light-controlled alignment substrate, and enabling precise control of the polarization angle of the output linearly polarized light over a large area, pixel-level micro-region (the smallest pixel size of the exposure pattern, i.e., a pattern unit). This allows for free and flexible adjustment of the polarization angle within a pixel-level micro-region in light-controlled alignment or other semiconductor lithography scenarios, and can be applied to the fabrication of liquid crystal optical elements with complex light-controlled orientation exposure patterns.

[0049] Compared to other photo-controlled alignment schemes, the projection exposure system provided in this embodiment eliminates the need for expensive masks and simplifies the processing flow. It enables large-area, high-efficiency, and high-precision micro-area control of liquid crystal alignment, offering advantages such as low cost and real-time controllability and tuning. This is of great significance for liquid crystal applications in both display and non-display fields. Furthermore, it also has broad application potential in semiconductor polarization-related photolithography scenarios.

[0050] Moreover, the projection exposure system provided in this application embodiment can provide linearly polarized light at a specific azimuth angle as needed, and can be widely used in other exposure application scenarios.

[0051] In some embodiments, the projection exposure system further includes at least one of the following:

[0052] Each liquid crystal micro-switches are used to correspond one-to-one with each pattern unit of the exposure pattern; or, N×M liquid crystal micro-switches are used to correspond to one pattern unit of the exposure pattern, where N and M are both positive integers; one pattern unit represents the minimum pixel size of the exposure pattern.

[0053] The azimuth angle of the second linearly polarized light is linearly related to the designed phase difference.

[0054] The phase delay waveplate 5 includes a quarter-wave plate, which is used to generate a phase delay, that is, to generate a phase difference of π / 2 between the vertical component and the parallel component of the light output by the liquid crystal phase delayer 4.

[0055] Optionally, the azimuth angle of the second linearly polarized light is half of the designed phase difference of the liquid crystal phase retarder 4.

[0056] Optionally, the light source 1 can be a coherent light source 1 such as a laser, or an incoherent light source 1 such as an LED or a halogen lamp.

[0057] In some embodiments, such as Figure 3 As shown, the liquid crystal micro-switcher includes:

[0058] The stacked components include a first polarizer 301, a first substrate 302, a switching circuit 304, a first electrode 305, a protective layer 306, a first liquid crystal cell unit, a second electrode 312, a second substrate 313, and a second polarizer 314; the switching circuit 304 is electrically connected to both the first electrode 305 and the second electrode 312.

[0059] The LCD switch panel 3 also includes a first control circuit 303, which is electrically connected to the switch circuits 304 of each LCD micro-zone switch.

[0060] In some embodiments, such as Figure 3 As shown, it also includes at least one of the following:

[0061] The first liquid crystal functional cell unit includes a first alignment layer 307, a first liquid crystal functional layer and a second alignment layer 311 stacked together; the first liquid crystal functional layer includes a first liquid crystal layer 310 located in the middle region, a first spacer 309 and a first sealing adhesive 308 located in the peripheral region.

[0062] Specifically, the first liquid crystal functional cell unit includes a first alignment layer 307 and a second alignment layer 311 disposed opposite to each other, a first sealing adhesive 308 disposed between the peripheral regions of the first alignment layer 307 and the peripheral regions of the second alignment layer 311, and a first liquid crystal layer 310 and a first spacer 309 contained in a first cavity surrounded by the first alignment layer 307, the second alignment layer 311 and the first sealing adhesive 308.

[0063] The transmission direction of the first polarizer 301 is perpendicular to the transmission direction of the second polarizer 314.

[0064] The first liquid crystal layer 310 includes a twisted nematic liquid crystal (TN liquid crystal), a vertically aligned liquid crystal (VA liquid crystal), or an advanced super-dimensional switch liquid crystal (ADS liquid crystal).

[0065] In some embodiments, it also includes at least one of the following:

[0066] Using the vertically upward optical axis as a reference (e.g.) Figure 2 The positive x-axis direction (i.e., the direction of the perpendicular component of the light vector) has the following orientations: the first polarizer 301 has a transmission direction of 90 degrees, the first alignment layer 307 has an orientation direction of 90 degrees, the second alignment layer 311 has an orientation direction of 0 degrees, and the second polarizer 314 has a transmission direction of 0 degrees.

[0067] The twist angle of a twisted nematic liquid crystal is 90 degrees or 270 degrees. Of course, other angles are also possible.

[0068] Optionally, the first substrate 302 is a transparent substrate and can be made of transparent materials, such as glass, polymer, etc.

[0069] Optionally, the protective layer 306 comprises a resin material.

[0070] Optionally, the height of the first septum 309 is 1–4 μm (micrometers).

[0071] It should be noted that the angular combinations between the various optical elements can be varied. For simplicity, this application only provides a detailed description of one such combination, such as... Figure 2 As shown. The angle combinations between various optical elements require overall design. A change in the angle of one optical element will cause a corresponding change in the angles of many other elements, but all of these changes are within the scope of the optical principles described in this application.

[0072] For example, in combination Figure 1 and Figure 2 Let me introduce the working principle of the liquid crystal micro-switches. Under the action of an external electric field, the rotation of the liquid crystal can be controlled.

[0073] Taking the first liquid crystal layer 310 as an example of a TN liquid crystal, the working principle of the liquid crystal micro-switching is introduced.

[0074] Specifically, when the light beam output from light source 1 passes through the first polarizer 301, it becomes vertically polarized light, specifically 90° linearly polarized light. In the absence of voltage, the TN liquid crystal is in a twisted spiral state, and the first linearly polarized light undergoes optical rotation. The polarization state of the emitted first linearly polarized light is 0°, parallel to the second polarizer 314, and thus it can pass through the second polarizer 314. Under the applied voltage, the TN liquid crystal, under the influence of an electric field, is oriented perpendicular to the first substrate 302 and the second substrate 313. The polarization state of the first linearly polarized light remains unchanged, and its vibration direction is 90°, meaning the polarization state is 90°, perpendicular to the second polarizer 314, and it cannot pass through the second polarizer 314, resulting in extinction.

[0075] In the absence of voltage, the first linearly polarized light passes through the second polarizer 314, i.e., it "transmits". When a voltage is applied, the first linearly polarized light cannot pass through the second polarizer 314, i.e., it is "extinct". The different light transmission patterns within the different liquid crystal micro-switches together form the desired bright area pattern.

[0076] In some embodiments, such as Figure 4 As shown, the liquid crystal phase delay device 4 includes: a stacked third substrate 401, a third electrode 403, a second liquid crystal functional cell unit, a fourth electrode 409, and a fourth substrate 410; the liquid crystal phase delay device 4 also includes a second control circuit 402, which is electrically connected to the third electrode 403 and the fourth electrode 409.

[0077] In some embodiments, such as Figure 4 As shown, it also includes at least one of the following:

[0078] The third electrode 403 or the fourth electrode 409 is a whole surface. The electrodes in the liquid crystal phase retarder 4 are unpatterned, which does not aggravate diffraction problems and can improve the alignment accuracy.

[0079] The second liquid crystal functional cell unit includes a stacked third alignment layer 404, a second liquid crystal functional layer, and a fourth alignment layer 408.

[0080] The second liquid crystal functional layer includes a second liquid crystal layer 407 located in the middle region, a second spacer 406, and a second sealant 405 located in the peripheral region; the orientation direction of the third alignment layer 404 is parallel to the orientation direction of the fourth alignment layer 408; the second liquid crystal layer 407 includes electrically controlled birefringence (ECB).

[0081] Optionally, the third substrate 401 is a transparent substrate, which can be made of transparent materials, such as glass, polymer, etc.

[0082] Optionally, the third electrode 403 is a transparent electrode.

[0083] Optionally, the height of the second septum 406 is 1–10 μm (micrometers).

[0084] Optionally, the fourth electrode 409 is a transparent electrode.

[0085] Optionally, the fourth substrate 410 is a transparent substrate and can be made of transparent materials, such as glass, polymer, etc.

[0086] In some embodiments, it also includes at least one of the following:

[0087] With the vertically upward optical axis as a reference, the orientation direction of the third orientation layer 404 is 45 degrees, and the orientation direction of the fourth orientation layer 408 is -135 degrees or 45 degrees.

[0088] Electrically controlled birefringence (ECB) liquid crystals can be either positive or negative liquid crystals.

[0089] The third orientation layer 404 and the fourth orientation layer 408 are either forward parallel or reverse parallel. In practical applications, they are generally reverse parallel.

[0090] Figure 2 In the diagram, the positive x-axis is the vertically upward direction of the optical axis, which is parallel to the direction perpendicular to the light vector; the positive y-axis is parallel to the direction parallel to the light vector; and the positive z-axis is the direction of light propagation.

[0091] Figure 2 The angles between each optical element and the x-axis are as follows: 90° for the transmission direction of the first polarizer 301; 90° for the upper liquid crystal layer 310 (TN liquid crystal) and 0° for the lower liquid crystal layer 310 along the optical axis; 0° for the transmission direction of the second polarizer 314; 45° for the optical axis of the liquid crystal phase retarder 4; 0° for the optical axis of the phase retarder waveplate 5 (1 / 4 waveplate); and δ / 2 for the polarization direction of the light received by the light-controlled alignment substrate 9.

[0092] The liquid crystal phase retarder 4 provided in this application embodiment has a whole-area structure, which can solve the light diffraction problem and improve the alignment accuracy.

[0093] The working principle of the liquid crystal phase retarder 4 is as follows: Due to the birefringence effect of liquid crystal molecules, the electric vector vibration directions perpendicular to and parallel to the principal plane have different refractive indices. In this application, the liquid crystal orientation direction of the second liquid crystal layer 407 is 45° or -135°. When first linearly polarized light with a polarization state of 0° is incident, the refractive indices differ in the parallel and perpendicular components. After traveling the same propagation distance, the electric vectors of the parallel and perpendicular components will be subject to different phase retardations. Furthermore, since the liquid crystal will deflect under the influence of an electric field, the birefringence will change with the deflection angle of the liquid crystal molecules. Therefore, different phase differences δ can be generated between the parallel and perpendicular components by voltage control; that is, the perpendicular and parallel components have a designed phase difference δ.

[0094] Combination Figure 1 and Figure 2 The optical principle of the projection exposure system of this application is described in detail below:

[0095] The polarization state E of the light beam output from light source 1 as it passes through the entire projection exposure system is calculated using the Jones matrix. out .

[0096] When the liquid crystal micro-switcher is turned on, the polarization state E of the output light out for:

[0097]

[0098] In the first line of Expression 1 above, there are 7 matrices (with boxes) from right to left. These 7 matrices represent: the polarization state of the input beam, the first polarizer 301 matrix, the second polarizer 314 matrix, the rotation matrix A of the liquid crystal phase retarder 4, the liquid crystal phase retarder 4 matrix, the rotation matrix B of the liquid crystal phase retarder 4, and the 1 / 4 waveplate matrix.

[0099] In the above expression 1, δ represents the phase difference of the liquid crystal phase retarder 4 along the x-axis (i.e., the perpendicular component of the light vector) and the y-axis (parallel component of the light vector), E yin The input is the light Jones matrix;

[0100] In expression 1 above, J′ TN(θ) Jones matrix for TN liquid crystal switches, specifically including:

[0101] J′ TN(θ) =J (θ) J R(Φ) J (-θ)··· J (θ / N) J (Φ) J (θ) J (-θ / N) ………(Expression 2)

[0102]

[0103] In expressions 2 and 3 above, θ is the total twist angle of the TN liquid crystal molecules; the liquid crystal molecule model is divided into N layers; the twist angle of each layer of liquid crystal molecules is θ / N; Φ is the total phase retardation of the TN liquid crystal cell; J R(Φ) J′ is the initial Jones matrix of the liquid crystal layer. TN(θ) The total Jones matrix of the TN liquid crystal layer;

[0104] The polarization state E of the output light above out The calculation results show that:

[0105] (1) Polarization state E of the output light out It is linearly polarized light;

[0106] (2) Polarization state E of the output light out The polarization direction (i.e., azimuth angle) is δ / 2. The polarization angle of the output light is uniquely determined by the phase difference δ between the parallel and perpendicular components of the electric vector generated by the liquid crystal phase retarder 4. The two components have a very easy-to-control linear relationship. Therefore, the phase delay of the liquid crystal phase retarder 4 can be easily and in real-time controlled by voltage.

[0107] In summary, by simply controlling the voltage of the liquid crystal phase retarder 4, the polarization direction (i.e., azimuth angle) of the output light can be quickly and easily adjusted within the plane of the light-controlled alignment substrate from 0 to 2π, thus allowing for arbitrary adjustment of the light-controlled alignment angle.

[0108] In some embodiments, such as Figure 1 As shown, the projection exposure system also includes: a beam expander 2 and a focusing lens 5;

[0109] The beam expander 2 is positioned between the light source 1 and the LCD switch panel 3 to increase the beam diameter and improve the processing area.

[0110] Optionally, the beam expander 2 may be a Galilean beam expander, a combination of concave and convex lenses, or other beam expanders.

[0111] The focusing lens 5 is positioned after the phase delay waveplate 5. Specifically, the focusing lens 5 is positioned between the phase delay waveplate 5 and the light-controlled alignment substrate 9 to converge light rays and adjust the distance to the light-controlled alignment substrate 9.

[0112] Optionally, the projection exposure system also includes a displacement platform 10. The photo-aligned substrate 9 is placed on the displacement platform 10, and the spatial position of the photo-aligned substrate 9 is adjusted using the displacement platform 10. A high-precision displacement platform 10 may be selected.

[0113] In some embodiments, such as Figure 1As shown, the projection exposure system also includes a control device. The control device includes a first computer 7 and a second computer 8. The first computer 7 is electrically connected to the liquid crystal switch panel 3; the second computer 8 is electrically connected to the liquid crystal phase delay unit 4.

[0114] Based on the same inventive concept, this application provides a control method for a projection exposure system, applied to the projection exposure system provided in any of the above embodiments. The control method includes:

[0115] The liquid crystal micro-switches in the corresponding light-transmitting area of ​​the control liquid crystal switch panel 3 are turned on to allow the first linearly polarized light to pass through, while all remaining liquid crystal micro-switches are turned off. The light-transmitting area is an exposure pattern corresponding to the light-controlled alignment substrate to be exposed, and the exposure pattern includes at least one pattern unit of the same light-controlled alignment.

[0116] The liquid crystal phase delay device 4 is controlled to generate phase delays for the vertical and parallel components of the first linearly polarized light, so that the vertical and parallel components have a designed phase difference. After phase delay by the phase delay waveplate 5, the second linearly polarized light is obtained and output. The azimuth angle of the second linearly polarized light corresponds to the designed phase difference, so that the liquid crystal formation in the light-transmitting area in the light-controlled alignment substrate is aligned with the azimuth angle of the second linearly polarized light.

[0117] Taking the fabrication of a liquid crystal polarizing grating as an example, the control method of the projection exposure system is explained.

[0118] Liquid crystal polarization grating structure: such as Figure 5 As shown, within the plane of the light-controlled alignment substrate, the alignment angles of the liquid crystal molecules arranged within the plane of the light-controlled alignment substrate are as follows: Figure 5 The pattern shown is as follows: Along the positive x-axis, the liquid crystal orientation remains consistent. Along the positive y-axis, the liquid crystal orientation angle gradually changes from 0° to 160°, with each column having an orientation angle interval of 20°. That is, from left to right, the liquid crystal orientation angles are 0°, 20°, 40°, 60°, 80°, 100°, 120°, 140°, and 160°.

[0119] Figure 5 In the diagram, each column of small squares represents an exposure pattern, each small square represents a pattern unit, and the double-headed arrows represent the liquid crystal alignment angle.

[0120] Figure 7 In this image, the small squares on the left with gray shading and double-headed arrows represent the previous 5 exposure patterns. The small squares without gray shading but with double-headed arrows represent the current exposure pattern.

[0121] If multiple light-controlled orientation exposures are performed using a mask method, nine masks are required for multiple exposures when the angle interval is 20°, resulting in huge mask costs.

[0122] The fabrication process of the liquid crystal polarizing grating corresponding to the multi-projection exposure system of this application is as follows:

[0123] Step (1) Single exposure (e.g.) Figure 6 As shown): The first computer controls the first column region (transparent region) in the x-axis direction corresponding to the liquid crystal micro-area switch to allow light to pass through, while controlling the light blocking of the remaining regions (e.g. Figure 6 (Middle gray shaded area). The voltage of the liquid crystal phase retarder is controlled by a second computer, making the phase difference δ between the vertical and parallel components of the electric vector (light vector) zero. At this point, the polarization state of the output light from the projection exposure system makes an angle of δ / 2 with the x-axis, which is 0°. By controlling the voltage of the liquid crystal phase retarder, the magnitude of the phase difference δ is controlled, thereby controlling the magnitude of the polarization state of the output light from the projection exposure system. Since the output light is linearly polarized, and the photo-alignment substrate is made of a photo-alignment material, the linear polarization is strictly related to the orientation angle of the molecules in the photo-alignment material. That is, the polarization state of the output light controls the orientation angle of the photo-alignment substrate; that is, as the polarization state of the output light changes to linearly polarized light, the orientation angle of the photo-alignment substrate also changes. For example... Figure 6 As shown, a liquid crystal alignment conforming to the design principle is formed in the first column region (i.e., the liquid crystal alignment in the first column region is 0°, and...). Figure 5 Consistent).

[0124] Step (2) Multiple exposures (e.g.) Figure 7 (As shown): Repeat step (1), change the light-transmitting area corresponding to the liquid crystal micro-switches through the first computer, and control the light blocking of the remaining areas (such as...). Figure 7 (The gray shaded area), and adjust the voltage of the liquid crystal phase retarder through a second computer, thereby controlling the magnitude of the phase difference δ loaded on the liquid crystal phase retarder, thus changing the magnitude of the polarization state of the output light of the projection exposure system and the angle δ / 2 with the x-axis, thereby forming the orientation arrangement in the corresponding area. Repeat step (1) multiple times until the desired orientation pattern is formed.

[0125] For example, the phase difference δ of the liquid crystal phase retarder is controlled by a second computer to be 0, 40, 80, 120, 160, 200, 240, 280, and 320 degrees. This results in the azimuth angle δ / 2 of the polarization state of the output light being 0°, 20°, 40°, 60°, 80°, 100°, 120°, 140°, and 160°. Since the molecular arrangement angle of the photo-controlled alignment substrate is strictly related to the azimuth angle of the polarization state of the output light, the liquid crystal alignment angles of the photo-controlled alignment substrate are 0°, 20°, 40°, 60°, 80°, 100°, 120°, 140°, and 160°. This ensures the liquid crystal alignment required for the formation of all liquid crystals, ultimately forming the desired exposure alignment pattern.

[0126] It should be noted that photo-alignment materials can be photoisomerized, photodegraded, or photocrosslinked. Among these, the reaction in photoisomerization is reversible, meaning it is erasable and rewritable. Once the alignment of an area is determined by light, it cannot be illuminated again. Therefore, liquid crystal switch panels have a zone function, which includes multiple arrays of liquid crystal micro-switches. Liquid crystal phase retarder structures are flat and do not have a zone function because adding structured electrodes would exacerbate diffraction and affect the clarity of the alignment pattern. Therefore, a combination of zoned switches and flat phase control is chosen.

[0127] The control method of the projection exposure system provided in this application can realize the polarization micro-region control of the liquid crystal orientation in any direction, the real-time control and preparation of arbitrary orientation patterns, and the precise control of the polarization angle of the output linearly polarized light on a large area, pixel-level micro-region (the smallest pixel size of the exposure pattern, i.e., a pattern unit). This enables the free adjustment of the polarization angle within the pixel-level micro-region in photo-controlled orientation or other semiconductor lithography scenarios, and can be applied to the preparation of complex photo-controlled orientation pattern liquid crystal optical elements.

[0128] Compared to other photo-controlled alignment schemes, the projection exposure system control method provided in this embodiment eliminates the need for expensive masks and simplifies the processing flow. It enables large-area, high-efficiency, and high-precision micro-area control of liquid crystal alignment, offering advantages such as low cost and real-time controllability and tuning. This is of great significance for liquid crystal applications in both display and non-display fields. Furthermore, it also has broad application potential in semiconductor polarization-related photolithography scenarios.

[0129] Furthermore, the control method of the projection exposure system provided in this application embodiment can provide linearly polarized light at a specific azimuth angle as needed, and can be widely applied to other exposure application scenarios.

[0130] By applying the embodiments of this application, at least the following beneficial effects can be achieved:

[0131] The projection exposure system provided in this application, by setting a light source, a liquid crystal switch panel, a liquid crystal phase retarder, and a phase retardation plate, allows the azimuth angle of the output linearly polarized light to change with the designed phase difference generated by the liquid crystal phase retarder. This enables the output of linearly polarized light with an arbitrary and flexible azimuth angle. Since the photo-alignment substrate is made of a photo-alignment material, the angle of molecular alignment of the material is strictly related to the azimuth angle (i.e., polarization direction) of the linearly polarized light. Therefore, the angle of molecular alignment of the photo-alignment substrate can be controlled by the azimuth angle of the linearly polarized light, thereby controlling the orientation of the liquid crystal molecules on the photo-alignment substrate. This allows for the fabrication of various liquid crystal optical elements with different functions. Therefore, by controlling the phase difference of the liquid crystal phase retarder, and thus controlling the azimuth angle of the output second linearly polarized light, the orientation arrangement of liquid crystal molecules in an exposure pattern on the photo-alignment substrate can be controlled. This application achieves real-time control and fabrication of exposure patterns with arbitrary light-controlled orientation by controlling the phase difference of the liquid crystal phase retarder, enabling precise control of the polarization orientation of a small region of liquid crystal on a light-controlled alignment substrate, and enabling precise control of the polarization angle of the output linearly polarized light over a large area, pixel-level micro-region (the smallest pixel size of the exposure pattern, i.e., a pattern unit). This allows for free and flexible adjustment of the polarization angle within a pixel-level micro-region in light-controlled alignment or other semiconductor lithography scenarios, and can be applied to the fabrication of liquid crystal optical elements with complex light-controlled orientation exposure patterns.

[0132] Compared to other photo-controlled alignment schemes, the projection exposure system provided in this embodiment eliminates the need for expensive masks and simplifies the processing flow. It enables large-area, high-efficiency, and high-precision micro-area control of liquid crystal alignment, offering advantages such as low cost and real-time controllability and tuning. This is of great significance for liquid crystal applications in both display and non-display fields. Furthermore, it also has broad application potential in semiconductor polarization-related photolithography scenarios.

[0133] Moreover, the projection exposure system provided in this application embodiment can provide linearly polarized light at a specific azimuth angle as needed, and can be widely used in other exposure application scenarios.

[0134] Those skilled in the art will understand that the steps, measures, and solutions in the various operations, methods, and processes discussed in this application can be alternated, modified, combined, or deleted. Furthermore, other steps, measures, and solutions in the various operations, methods, and processes discussed in this application can also be alternated, modified, rearranged, decomposed, combined, or deleted. Furthermore, steps, measures, and solutions in the prior art that are similar to those disclosed in this application can also be alternated, modified, rearranged, decomposed, combined, or deleted.

[0135] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0136] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0137] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0138] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0139] It should be understood that although the steps in the flowcharts of the accompanying figures are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the accompanying figures may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0140] The above description is only a partial embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A projection exposure system, characterized in that, include: A light source, a liquid crystal switch panel, a liquid crystal phase delayer, and a phase delay waveplate are arranged sequentially along the first direction; The light source is used to output a light beam; The liquid crystal switch panel includes multiple arrayed liquid crystal micro-switches for converting the light beam into first linearly polarized light and controlling whether the first linearly polarized light passes through; the liquid crystal phase delayer is used to generate phase delays for the vertical and parallel components of the first linearly polarized light, so that the vertical and parallel components have a designed phase difference. The liquid crystal phase delay device includes: a stacked third substrate, a third electrode, a second liquid crystal functional cell unit, a fourth electrode, and a fourth substrate; the liquid crystal phase delay device also includes a second control circuit, which is electrically connected to both the third electrode and the fourth electrode; the third electrode or the fourth electrode is a whole surface, and the electrodes in the liquid crystal phase delay device are unpatterned; The phase delay waveplate is used to delay the phase of the light output from the liquid crystal phase delayer to obtain and output second linearly polarized light. The azimuth angle of the second linearly polarized light corresponds to the designed phase difference. It also includes a control device for controlling the liquid crystal micro-switches in the corresponding light-transmitting area of ​​the liquid crystal switch panel to open, so that the first linearly polarized light can pass through, and at the same time controlling all remaining liquid crystal micro-switches to close; the light-transmitting area is an exposure pattern corresponding to the light-controlled alignment substrate to be exposed, and the exposure pattern includes at least one pattern unit with the same light orientation.

2. The projection exposure system according to claim 1, characterized in that, It also includes at least one of the following: Each of the liquid crystal micro-area switches is used to correspond one-to-one with each pattern unit of the exposure pattern; or, N×M of the liquid crystal micro-area switches are used to correspond to one of the pattern units of the exposure pattern, where N and M are both positive integers; The azimuth angle of the second linearly polarized light is linearly related to the designed phase difference; The phase delay waveplate includes a quarter-waveplate.

3. The projection exposure system according to claim 1, characterized in that, The liquid crystal micro-area switch includes: The system comprises a first polarizer, a first substrate, a switching circuit, a first electrode, a protective layer, a first liquid crystal functional cell unit, a second electrode, a second substrate, and a second polarizer, all stacked together; the switching circuit is electrically connected to both the first electrode and the second electrode. The liquid crystal switch panel also includes a first control circuit, which is electrically connected to the switch circuit of each of the liquid crystal micro-switches.

4. The projection exposure system according to claim 3, characterized in that, It also includes at least one of the following: The first liquid crystal functional cell unit includes a first alignment layer, a first liquid crystal functional layer and a second alignment layer stacked together; the first liquid crystal functional layer includes a first liquid crystal layer located in the middle region, a first spacer and a first sealing adhesive located in the peripheral region; The transmission direction of the first polarizer is perpendicular to the transmission direction of the second polarizer. The first liquid crystal layer includes a twisted nematic liquid crystal, a vertically aligned liquid crystal, or an advanced superdimensional field-conversion liquid crystal.

5. The projection exposure system according to claim 4, characterized in that, It also includes at least one of the following: With the vertically upward optical axis as a reference, the transmission direction of the first polarizer is 90 degrees, the orientation direction of the first alignment layer is 90 degrees, the orientation direction of the second alignment layer is 0 degrees, and the transmission direction of the second polarizer is 0 degrees. The twist angle of the twisted nematic liquid crystal is 90 degrees or 270 degrees.

6. The projection exposure system according to claim 1, characterized in that, It also includes at least one of the following: The second liquid crystal functional cell unit includes a stacked third alignment layer, a second liquid crystal functional layer, and a fourth alignment layer; The second liquid crystal functional layer includes a second liquid crystal layer in the middle region, a second spacer, and a second sealant in the peripheral region; the orientation direction of the third alignment layer is parallel to the orientation direction of the fourth alignment layer; the second liquid crystal layer includes electrically controlled birefringent liquid crystal.

7. The projection exposure system according to claim 6, characterized in that, It also includes at least one of the following: With the vertically upward optical axis as a reference, the orientation direction of the third orientation layer is 45 degrees, and the orientation direction of the fourth orientation layer is -135 degrees or 45 degrees; The electrically controlled birefringent liquid crystal is either a positive liquid crystal or a negative liquid crystal.

8. The projection exposure system according to claim 1, characterized in that, Also includes: Beam expander and focusing lens; The beam expander is disposed between the light source and the liquid crystal switch panel; The focusing lens is positioned after the phase delay waveplate.

9. The projection exposure system according to claim 1, characterized in that, It also includes a control device; the control device includes: A first computer is electrically connected to the LCD switch panel; The second computer is electrically connected to the liquid crystal phase delay device.

10. A control method for a projection exposure system, characterized in that, The control method, applied to the projection exposure system as described in any one of claims 2-9, comprises: The liquid crystal micro-switches in the corresponding light-transmitting area of ​​the liquid crystal switch panel are turned on to allow the first linearly polarized light to pass through, while all remaining liquid crystal micro-switches are turned off. The light-transmitting area is an exposure pattern corresponding to the light-controlled alignment substrate to be exposed, and the exposure pattern includes at least one pattern unit with the same light orientation. The liquid crystal phase retarder is controlled to generate phase delays for the vertical and parallel components of the first linearly polarized light, so that the vertical and parallel components have a designed phase difference. After the phase retarder waveplate generates phase delay, the second linearly polarized light is obtained and output. The azimuth angle of the second linearly polarized light corresponds to the designed phase difference, so that the liquid crystal in the light-controlled alignment substrate of the light-transmitting region forms an alignment arrangement consistent with the azimuth angle of the second linearly polarized light.

Images