Maskless lithography machine

Abstract

This invention discloses a maskless lithography machine and its control method. The maskless lithography machine includes: a laser, a homogenizer, a spatial light modulator, a projection lens, a substrate, a motion platform, a controller, and a light intensity sensor. The spatial light modulator rotates a fixed angle around the Z-axis relative to the XY plane of the motion platform, and its pattern refresh is synchronously controlled by a position trigger signal of the motion platform. The light intensity sensor is disposed on the motion platform and is used to measure the light intensity distribution of the spatial light modulator. The controller controls the operating parameters of the laser, the spatial light modulator, the motion platform, and the light intensity sensor. Based on the light intensity distribution of the spatial light modulator measured by the light intensity sensor, the controller shuts down some pixels on the spatial light modulator to achieve illumination uniformity compensation. After processing by the controller, the upper part of the pixels of the spatial light modulator is shut down, thereby achieving the effect of illumination uniformity compensation.

Description

Technical Field

[0001] This invention relates to the field of maskless lithography technology, and in particular to a maskless lithography machine. Background Technology

[0002] Masked lithography uses hardware structures such as variable transmittance illumination uniformity compensation plates or variable reflectance mirror arrays to compensate for illumination uniformity. Maskless lithography illumination uniformity compensation falls into two categories: one divides the spatial light modulator into a grid for uniformity compensation, and the other uses a CCD camera to measure illumination uniformity and then compensates for it. Both of these methods do not require additional hardware structures for illumination uniformity correction, but their accuracy and efficiency are lower.

[0003] In related technologies, the uniformity compensation schemes for maskless lithography have low computational accuracy and efficiency, making it difficult to meet the requirements for high-precision and rapid illumination uniformity compensation. Alternatively, illumination uniformity compensation in maskless lithography requires additional hardware structures, increasing system cost and complexity. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a maskless lithography machine in which the light intensity distribution of a spatial light modulator measured by a light intensity sensor is processed by a controller to turn off some pixels on the spatial light modulator, thereby achieving the effect of illumination uniformity compensation without the need for additional hardware compensation structures.

[0005] A maskless lithography machine according to an embodiment of the present invention includes: a laser; a homogenizer; a spatial light modulator; a projection lens disposed below the spatial light modulator; a motion platform on which a substrate is disposed and which selectively moves the substrate, the motion platform and the spatial light modulator being synchronized via a position signal of the motion platform, the spatial light modulator rotating about a fixed angle around the z-axis relative to the xy-plane of the motion platform, and the stepping distance of the motion platform being smaller than the display width of the spatial light modulator; a light intensity sensor disposed on the motion platform for measuring the light intensity distribution of the spatial light modulator; and a controller for controlling the laser, the spatial light modulator, the motion platform, and the light intensity sensor. The sensor's operating parameters; and the controller is configured to: turn on the laser and the spatial light modulator; control the motion platform to move the light intensity sensor under the lens; control the light intensity sensor to measure the light intensity distribution; generate illumination uniformity data based on the measured light intensity distribution and considering measurement errors, and send it to the spatial light modulator; obtain a two-dimensional image of the light intensity distribution measured by the light intensity sensor; statistically analyze the grayscale values ​​column by column based on the two-dimensional image; calculate the difference between each column using the column with the smallest grayscale value as a reference; compensate for the difference between each column according to the lens shadow model; calculate the number of pixels that need to be turned off in each column based on the difference between each column; and generate the spatial modulator illumination uniformity compensation BMP map based on the number of pixels turned off in each column.

[0006] According to the maskless lithography machine of the present invention, the light intensity distribution of the spatial light modulator measured by the light intensity sensor is processed by the controller to generate illumination uniformity compensation data. The controller sends the illumination uniformity data to the spatial light modulator, and by turning off some pixels on the spatial light modulator, the illumination uniformity compensation effect is achieved without the need to add a hardware compensation structure.

[0007] According to some embodiments of the present invention, the X-axis and Y-axis of the light intensity sensor are parallel to the X-axis and Y-axis of the motion platform; the image of the spatial light modulator obtained by the light intensity sensor is rotated by an angle θ.

[0008] According to some embodiments of the present invention, the angle between the Y-axis of the light intensity sensor (8) and the Y-axis of the motion platform (6) is θ2, the angle of rotation of the image of the spatial light modulator (3) obtained by the light intensity sensor (8) is θ1; and when the light intensity sensor rotates counterclockwise, θ, θ1 and θ2 satisfy the relationship: θ1-θ2=θ; when the light intensity sensor rotates clockwise, θ, θ1 and θ2 satisfy the relationship: θ-θ1=θ2.

[0009] According to some embodiments of the present invention, the ratio between the gray value of the light beam passing through the center of the lens illuminating the light intensity sensor and the gray value recorded by the light intensity sensor is a, and the ratio between the gray value of the light beam passing through the edge of the lens illuminating the light intensity sensor and the gray value recorded by the light intensity sensor is b, and a and b satisfy the relationship: a < b.

[0010] According to some embodiments of the present invention, the step of the controller controlling the motion platform to move the light intensity sensor under the lens further includes: the controller controlling the motion platform to adjust to the focal plane in the vertical direction.

[0011] According to some embodiments of the present invention, the motion platform, under the control of the controller, performs stepping motion in the X direction and scanning in the Y direction; or, the motion platform performs stepping motion in the X direction and reverse scanning in the Y direction.

[0012] According to some embodiments of the present invention, the light intensity sensor is a CMOS camera.

[0013] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0014] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0015] Figure 1 This is a simplified structural diagram of a maskless lithography machine according to an embodiment of the present invention;

[0016] Figure 2 This is a flowchart illustrating the measurement of light intensity distribution of a spatial light modulator using a light intensity sensor according to an embodiment of the present invention;

[0017] Figure 3 This is a flowchart illustrating the generation of illumination uniformity compensation data based on the measured light intensity distribution, according to an embodiment of the present invention.

[0018] Figure 4 This is a schematic diagram of tilt scanning according to an embodiment of the present invention;

[0019] Figure 5 This is a schematic diagram of the arrangement of two-dimensional images according to an embodiment of the present invention;

[0020] Figure 6 This is a partial schematic diagram of illumination uniformity compensation according to an embodiment of the present invention;

[0021] Figure 7 This is a partial schematic diagram of illumination uniformity compensation according to an embodiment of the present invention;

[0022] Figure 8 This is a partial schematic diagram of illumination uniformity compensation according to an embodiment of the present invention;

[0023] Figure 9 This is a schematic diagram of the spatial light modulator projected onto a light intensity sensor according to an embodiment of the present invention;

[0024] Figure 10 This is a schematic diagram of the spatial light modulator projected onto a light intensity sensor according to an embodiment of the present invention;

[0025] Figure 11 This is a schematic diagram illustrating the principle of measurement error generation at the lens in a spatial light modulator according to an embodiment of the present invention;

[0026] Figure 12 This is a compensation model for measurement errors generated at the lens in a spatial light modulator according to an embodiment of the present invention.

[0027] Figure label:

[0028] 1. Laser; 2. Beam homogenizer; 3. Spatial light modulator; 4. Lens; 5. Substrate; 6. Motion platform; 7. Controller; 8. Light intensity sensor; 9. Microlens; 10. Photoelectric sensor. Detailed Implementation

[0029] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention are described in detail below.

[0030] The following is for reference. Figures 1-12 The present invention describes a maskless lithography machine according to embodiments thereof, and also proposes a control method for the maskless lithography machine.

[0031] For photolithography systems, illumination uniformity directly affects the critical size uniformity of the exposed pattern. Illumination uniformity can be achieved using homogenizing devices such as compound eye microlens arrays and light bars. However, due to limitations in the performance of the homogenizing devices themselves and inherent errors in the optical system, achieving satisfactory illumination uniformity is difficult. Therefore, illumination uniformity compensation measures are needed to achieve consistent illumination uniformity.

[0032] In the maskless lithography machine of this invention, the machine includes: a laser 1, a beam homogenizer 2, a spatial light modulator 3, and a lens 4. The spatial light modulator 3 corresponds to the laser 1, and the lens 4 is disposed below the spatial light modulator 3. Maskless lithography uses the spatial light modulator 3 to directly image the modulated beam onto the photosensitive material. The beam homogenizer 2 is used to homogenize the beam emitted by the laser 1. The laser 1 is a laser, and the beam emitted by the laser passes through the beam homogenizer 2, making the beam more uniform. The beam homogenizer 2 increases the uniformity of the laser intensity distribution, forming a surface laser 1 with a uniformly distributed light intensity on the output surface.

[0033] Compared to masked lithography, maskless lithography allows the spatial light modulator 3 to replace the photomask, and the image on the spatial light modulator 3 is controlled by the controller 7. Therefore, illumination uniformity compensation in maskless lithography can fully utilize the independently controllable feature of the spatial light modulator 3 to perform illumination uniformity compensation without adding additional hardware structures for illumination uniformity compensation. Furthermore, maskless lithography saves on expensive photomask fabrication costs and reduces the photomask fabrication cycle compared to masked lithography. For multiple batches of small-volume products, maskless lithography has significant advantages.

[0034] Maskless lithography can be divided into step-repetitive and step-scan lithography, with step-scan lithography being more efficient and becoming the main exposure method. Compared to step-repetitive lithography, the energy in the exposed image of step-scan lithography is the sum of the energy integrals of each point on the spatial light modulator 3 along the scanning direction, rather than the integral of the energy of a single point on the spatial modulator in step-repetitive lithography. Therefore, the illumination uniformity of step-scan lithography can be compensated by controlling the number of times the spatial light modulator 3 is superimposed along the scanning direction.

[0035] Furthermore, the maskless lithography machine also includes: a motion platform 6, on which a substrate 5 is disposed, and the motion platform 6 selectively moves the substrate 5. The motion platform 6 is electrically connected to a spatial light modulator 3. The spatial light modulator 3 and the motion platform 6 are parallel to each other, and the edges of the spatial light modulator 3 and the edges of the motion platform 6 are inclined relative to each other. The step distance of the motion platform 6 is smaller than the display width of the spatial light modulator 3. The spatial light modulator 3 is rotated at an angle relative to the XY plane of the motion platform 6. A schematic diagram of the tilted spatial light modulator 3 is shown below. Figure 4 As shown, after the spatial light modulator 3 is tilted, the spacing between adjacent pixels in the X and Y directions is smaller than the spacing between the pixels themselves, thereby improving the lithographic resolution.

[0036] In this system, the laser beam emitted by laser 1 reaches spatial light modulator 3. Spatial homogenizer, controlled by controller 7, modulates the exposure pattern and projects it onto a substrate 5 coated with a photosensitive material through a projection lens. Substrate 5 is placed on motion platform 6, which, under the control of controller 7, moves in steps in the X direction and scans in the Y direction. Motion platform 6 scans at a uniform speed in the Y direction and generates a synchronization signal according to either equidistant triggering or time-equidistant triggering. This synchronization signal is used to refresh the image in spatial light modulator 3 to complete the scanning exposure.

[0037] Once a strip scan exposure is complete, the motion platform 6 performs a stepping motion in the X direction, and then performs a reverse scan in the Y direction, and so on. The motion platform 6 moves in a zigzag pattern to complete the exposure of the entire substrate 5.

[0038] Furthermore, the maskless lithography machine also includes a light intensity sensor 8, which is mounted on the motion platform 6 and used to measure the light intensity distribution at the spatial light modulator 3. Thus, by measuring the light intensity distribution at the spatial light modulator 3 using the light intensity sensor 8, the uniformity of illumination can be visually assessed.

[0039] Furthermore, the light intensity sensor 8 is placed on the motion platform 6, which can move in the XY plane and move up and down in the z-axis direction. When the light intensity sensor 8 is below the lens 4, the height of the Z-axis can be adjusted to achieve focusing and measure the light intensity distribution at the spatial light modulator 3.

[0040] Furthermore, the maskless lithography machine also includes a controller 7. The input of the controller 7 is electrically connected to the light intensity sensor 8, and the output of the controller 7 is electrically connected to the motion platform 6, the spatial light modulator 3, and the laser 1. In addition, the controller 7 is configured to turn off a portion of the pixels on the spatial light modulator 3 based on the light intensity distribution measured by the light intensity sensor 8, thereby achieving illumination uniformity compensation. That is, the light intensity distribution of the spatial light modulator 3 measured by the light intensity sensor 8 is processed by the controller 7 to generate illumination uniformity compensation data. The controller 7 then sends the illumination uniformity data to the spatial light modulator 3 to turn off a portion of the pixels on the spatial light modulator 3, thus achieving the effect of illumination uniformity compensation without requiring additional hardware compensation structures.

[0041] The following reference Figures 1-12 The present invention describes a control method for a maskless lithography machine, the control method comprising:

[0042] First, turn on the laser 1 and the spatial light modulator 3. The controller 7 controls the motion platform 6 to move the light intensity sensor 8 under the lens 4. The controller 7 then controls the light intensity sensor 8 to measure the light intensity distribution.

[0043] Next, the controller 7 generates illumination uniformity data based on the measured light intensity distribution and taking into account measurement errors, and sends it to the spatial light modulator 3. The controller 7 then obtains a two-dimensional image of the light intensity distribution measured by the light intensity sensor 8.

[0044] Then, based on the two-dimensional image, the gray values ​​are counted column by column. The column with the smallest gray value among the multiple columns is used as the benchmark to calculate the difference between each column. The difference between each column is compensated according to the lens 4 shadow model.

[0045] like Figure 4 As shown, specifically, the original image is cut into strips, with overlapping areas between the strips, and the data of each strip is tilted. The tilted data is displayed by the spatial light modulator, while the spatial light modulator 3 tilts in the opposite direction, ensuring that the pattern exposed on the substrate 5 is upright. The motion platform 6 steps at a distance less than the display width in the X direction, causing the stitching areas to overlap.

[0046] like Figure 5 As shown, the splicing area is formed by the superposition of two triangles on both sides of the spatial light modulator 3 after tilting. The side length of the parallelogram formed by the superposition of the splicing areas in the Y direction is equal to the side length of the parallelogram in the Y direction of the non-splicing area.

[0047] like Figure 6 As shown, after merging the spliced ​​and non-spliced ​​areas, the gray values ​​are counted by column, and the difference between each column is calculated based on the minimum gray value of the column.

[0048] Finally, as Figure 7 As shown, based on the differences in each column, the number of pixels that need to be turned off in each column is calculated; based on the number of pixels turned off in each column, a spatial modulator illumination uniformity compensation BMP image is generated. The calculation of the number of pixels turned off in each column based on the grayscale differences is as follows: Figure 7 As shown, for non-stitched areas, pixels in each column are turned off from top to bottom. When the sum of the gray values ​​of the turned-off pixels equals the gray value difference of that column, the number of pixels turned off is the number of pixels that need to be turned off in that column. For stitched areas, the gray value difference of each column is first distributed to the two triangles on both sides according to a ratio determined by the gray value of the two triangles on both sides of the column. Then, pixels in the left triangle are turned off from top to bottom, while pixels in the right triangle are turned off from bottom to top. When the sum of the gray values ​​of the turned-off pixels equals the gray value difference of their respective columns, the number of pixels turned off is the number of pixels that need to be turned off in the two triangles on both sides.

[0049] like Figure 8As shown, the illumination compensation BMP image of the spatial light modulator 3 is generated by calculating the closed pixels in each column. The columns in the left triangle and middle region are rotated clockwise around the top, with the rotation angle equal to the tilt angle of the spatial light modulator 3. The columns in the right triangle region are rotated clockwise around the bottom, with the rotation angle equal to the tilt angle of the spatial light modulator 3. The right side of the data after the left triangle is tilted is merged with the left side of the data after the middle region is tilted, and the right side of the data after the middle region is tilted is merged with the left side of the data after the right triangle is tilted, ultimately generating the illumination uniformity compensation BMP image of the spatial light modulator 3. The exposure image data is ANDed with the illumination uniformity template of the spatial light modulator 3, meaning that only data with the same value of 1 is ANDed, generating the required exposure data, thus achieving the effect of consistent energy integrals in each column of the exposure data.

[0050] The step of controller 7 controlling motion platform 6 to move light intensity sensor 8 below lens 4 further includes: controller 7 controlling motion platform 6 to adjust vertically to the focal plane. That is, light intensity sensor 8 is placed on motion platform 6 and can be moved by motion platform 6 in the XY plane and vertically along the Z-axis. When light intensity sensor 8 is below lens 4, the Z-axis height can be adjusted to achieve focusing and measure the light intensity distribution at spatial light modulator 3. The laser energy focused at the focal point should be sufficient to etch and remove material from the surface of substrate 5 at the focal point.

[0051] Therefore, the light intensity distribution of the spatial light modulator 3 measured by the light intensity sensor 8 is processed by the controller 7 to generate illumination uniformity compensation data. The controller 7 then sends the illumination uniformity data to the spatial light modulator 3. By turning off some pixels on the spatial light modulator 3, the illumination uniformity compensation effect is achieved without the need to add a hardware compensation structure.

[0052] And, refer to Figure 9 As shown, the X and Y axes of the light intensity sensor 8 are parallel to the X and Y axes of the motion platform 6, and the image of the spatial light modulator 3 obtained by the light intensity sensor 8 is rotated by an angle θ. This setting ensures that the two-dimensional image captured by the light intensity sensor 8 corresponds to the image on the substrate 5, thereby enabling accurate calculation of the grayscale values ​​of the actual scanned columns.

[0053] Or, as Figure 9 and Figure 10 As shown, the angle between the Y-axis of the light intensity sensor 8 and the Y-axis of the motion platform 6 is θ2, and the angle of rotation of the image of the spatial light modulator 3 obtained by the light intensity sensor 8 is θ1.

[0054] like Figure 9As shown, when the light intensity sensor 8 rotates counterclockwise, θ, θ1, and θ2 satisfy the relationship: θ1 - θ2 = θ. Due to the installation error of the light intensity sensor 8, the light intensity sensor 8 rotates counterclockwise relative to the motion platform 6. At this time, there is an angle between the X and Y axes of the light intensity sensor 8 and the X and Y axes of the motion platform 6, resulting in the following... Figure 9 As shown in the intermediate image, the angle between the projection of the spatial light modulator 3 onto the light intensity sensor 8 and the X-axis of the light intensity sensor 8 is greater than the actual rotation angle of the spatial light modulator 3. Specifically, the angle θ1 between the projection of the spatial light modulator 3 onto the light intensity sensor 8 and the X-axis of the light intensity sensor 8 is equal to the sum of the actual rotation angle θ of the spatial light modulator 3 and the angle θ2 between the X-axis of the light intensity sensor 8 and the X-axis of the motion platform 6. To obtain accurate statistical grayscale values ​​of the actual scanned columns, the image of the spatial light modulator 3 obtained on the light intensity sensor 8 needs to be rotated by θ2. At this time, the grayscale values ​​are counted column by column, and the counted grayscale values ​​are the actual scanned column grayscale values.

[0055] And, such as Figure 10 As shown, when the light intensity sensor 8 rotates clockwise, θ, θ1, and θ2 satisfy the relationship: θ - θ1 = θ2. Due to the installation error of the light intensity sensor 8, the light intensity sensor 8 rotates clockwise relative to the motion platform 6. At this time, there is an angle between the X and Y axes of the light intensity sensor 8 and the X and Y axes of the motion platform 6, resulting in the following... Figure 10 As shown in the intermediate image, the angle between the projection of the spatial light modulator 3 onto the light intensity sensor 8 and the X-axis of the light intensity sensor 8 is smaller than the actual rotation angle of the spatial light modulator 3. Specifically, the sum of the angle θ1 between the projection of the spatial light modulator 3 onto the light intensity sensor 8 and the X-axis of the light intensity sensor 8, and the angle θ2 between the X-axis of the light intensity sensor 8 and the X-axis of the motion platform 6, is equal to the actual rotation angle θ of the spatial light modulator 3. To obtain accurate statistical grayscale values ​​of the actual scanned columns, the image of the spatial light modulator 3 obtained on the light intensity sensor 8 needs to be rotated by θ2. At this time, the grayscale values ​​are statistically analyzed column by column, and the statistical grayscale values ​​are the actual scanned column grayscale values.

[0056] And, refer to Figure 11As shown, light beams A and B from the spatial light modulator 3 reach positions a and b of the light intensity sensor 8 via lens 4. The angles between beams A and B and the optical axis O are θ and β, respectively. The microstructure of the pixel in the light intensity sensor 8 includes a microlens 9 and a photoelectric sensor 10. The ability of the microlens 9 in the light intensity sensor 8 to collect the light beam is related to the incident angle; the larger the incident angle, the worse the beam-collecting ability of the microlens 9, and the lower the quantum efficiency of the photoelectric sensor 10. This phenomenon is called lens shading, meaning that the light intensity collected by the light intensity sensor 8 exhibits a pattern of strong intensity in the center and weak intensity at the edges. Therefore, when statistically analyzing the grayscale differences column by column, in addition to the differences caused by inconsistent illumination intensity uniformity, the measurement error of the light intensity sensor 8 is also included. To accurately measure the illumination intensity distribution and compensate for illumination uniformity based on the measurement results, the measurement error must be considered.

[0057] Thus, referring to Figure 11 and Figure 12 As shown, the ratio between the grayscale value of the light beam passing through the center of lens 4 and the grayscale value recorded by the light intensity sensor 8 is 'a', and the ratio between the grayscale value of the light beam passing through the edge of lens 4 and the grayscale value recorded by the light intensity sensor 8 is 'b'. 'a' and 'b' satisfy the relationship: a < b. That is, when a two-dimensional image of the light intensity distribution of the light intensity sensor 8 is received, the grayscale value of the light beam passing through the center of lens 4 and the grayscale value recorded by the light intensity sensor 8 is larger than the actual grayscale value, thus controlling the reduction of the amount of grayscale value recorded by the light intensity sensor 8. Alternatively, when a two-dimensional image of the light intensity distribution of the light intensity sensor 8 is received, the grayscale value of the light beam passing through the edge of lens 4 and the grayscale value recorded by the light intensity sensor 8 is smaller than the actual grayscale value, thus controlling the increase of the amount of grayscale value recorded by the light intensity sensor 8. Thus, by increasing the gray value of the light beam passing through the edge of the lens 4 and illuminating the light intensity sensor 8, and by decreasing the gray value of the light beam passing through the center of the lens 4 and illuminating the light intensity sensor 8, the two-dimensional image of the light intensity distribution recorded by the light intensity sensor 8 is made closer to the real image of the two-dimensional image.

[0058] Furthermore, under the control of the controller 7, the motion platform 6 steps in the X direction and scans in the Y direction; or, the motion platform 6 steps in the X direction and performs a reverse scan in the Y direction. That is to say, when a strip scan exposure is completed, the motion platform 6 steps in the X direction and then performs a reverse scan in the Y direction, and so on, the motion platform 6 moves in a zigzag pattern to complete the exposure of the entire substrate 5.

[0059] Among them, the light intensity sensor 8 is a CMOS camera. The prerequisite for illumination uniformity compensation is obtaining the illumination intensity distribution and then performing illumination uniformity compensation based on this distribution. Common tools used for measuring illumination uniformity include power meters, energy meters, and photoelectric sensors 10. Power meters and energy meters can only measure overall energy and are difficult to obtain two-dimensional energy distribution information. Photoelectric sensors 10, such as CMOS cameras, with their two-dimensional array structure and high spatial resolution, are suitable for measuring the two-dimensional light intensity distribution of illumination. The inherent noise of the CMOS camera affects measurement accuracy; therefore, its noise impact must be considered to improve measurement accuracy, and consequently, improve the accuracy of illumination uniformity compensation based on the measurement results.

[0060] CMOS camera noise includes random noise and fixed noise. Random noise includes dark current and readout noise, while fixed noise refers to the inconsistent response caused by errors in the CMOS pixel fabrication process. To eliminate camera noise, a uniformity laser 1 is needed for calibration, and a camera lens needs to be installed. The integrating sphere uniformity laser 1 is relatively large, and the depth of focus of the lithography machine objective lens is small, making it difficult to integrate the uniformity laser 1 and the camera lens within the lithography machine.

[0061] Thus, by using a plate-level area array CMOS camera and the objective lens of the lithography machine as the lens of the CMOS camera, the light intensity distribution of the spatial light modulator 3 is measured. By using the measured light intensity distribution and taking into account the measurement error, an illumination uniformity compensation template for the spatial light modulator 3 is generated, thereby achieving the effect of uniform illumination.

[0062] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention 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 invention.

[0063] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0064] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A maskless lithography machine, characterized in that, It comprises: a laser (1); a homogenizer (2); a spatial light modulator (3); a projection objective (4) arranged below the spatial light modulator (3); a motion platform (6) on which a substrate (5) is arranged and which selectively drives the substrate (5) to move, the motion platform (6) and the spatial light modulator (3) are synchronized by a motion platform position signal, the spatial light modulator (3) rotates a fixed angle around the z-axis relative to the xy plane of the motion platform (6), and the step distance of the motion platform (6) is less than the display width of the spatial light modulator (3); a light intensity sensor (8) arranged on the motion platform (6), the light intensity sensor (8) is used to measure the light intensity distribution of the spatial light modulator (3), and the X and Y axes of the light intensity sensor (8) are parallel to the X and Y axes of the motion platform (6); the angle of rotation of the image of the spatial light modulator (3) obtained by the light intensity sensor (8) is θ; wherein the angle between the Y axis of the light intensity sensor (8) and the Y axis of the motion platform (6) is θ2, the angle of rotation of the image of the spatial light modulator (3) obtained by the light intensity sensor (8) is θ1; and when the light intensity sensor rotates counterclockwise, θ, θ1 and θ2 satisfy the relationship: θ1-θ2=θ, and when the light intensity sensor rotates clockwise, θ, θ1 and θ2 satisfy the relationship: θ-θ1=θ2; a controller (7) for controlling the working parameters of the laser (1), the spatial light modulator (3), the motion platform (6) and the light intensity sensor (8); and the controller (7) is configured to: turn on the laser (1) and the spatial light modulator (3); the controller (7) controls the motion platform (6) to move the light intensity sensor (8) below the projection objective (4); the controller (7) controls the light intensity sensor (8) to measure the light intensity distribution; the controller (7) generates illumination uniformity data according to the measured light intensity distribution and considering the measurement error, and sends it to the spatial light modulator (3); the controller (7) obtains a two-dimensional image of the light intensity distribution measured by the light intensity sensor (8); according to the two-dimensional image, the gray value is counted by column, when the light intensity sensor (8) rotates clockwise or counterclockwise, in order to accurately count the actual scanning column gray value, the image of the spatial light modulator (3) obtained on the light intensity sensor (8) is rotated by an angle of θ2, at this time the gray value is counted by column, then the counted gray value is the actual scanning column gray value; taking one column with the smallest gray value in multiple columns as a reference, calculate the difference value of each column; compensate for the difference value of each column according to the shadow model of the projection objective (4); according to the difference value of each column, calculate the number of pixels that need to be turned off in each column; according to the number of pixels turned off in each column, generate the spatial light modulator illumination uniformity compensation BMP map.

2. The maskless lithography machine of claim 1, wherein, The ratio between the gray value of the light beam irradiated on the light intensity sensor (8) through the center of the projection objective (4) and the gray value recorded by the light intensity sensor (8) is a, and the ratio between the gray value of the light beam irradiated on the light intensity sensor (8) through the edge of the projection objective (4) and the gray value recorded by the light intensity sensor (8) is b, a and b satisfy the relationship: a < b.

3. The maskless lithography machine of claim 1, wherein, The step of the controller (7) controlling the motion platform (6) to move the light intensity sensor (8) under the projection objective (4) further comprises: The controller (7) controls the motion platform (6) to adjust to the focal plane in the up-down direction.

4. The maskless lithography machine of claim 1, wherein, The motion platform (6) is controlled by the controller (7) to step in the X direction and scan in the Y direction; or, The motion platform (6) steps in the X direction and reversely scans in the Y direction.

5. The maskless lithography machine of claim 1, wherein, The light intensity sensor (8) is a CMOS camera.

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