A method for calibrating an optical mechanism

Abstract

The application provides a method for calibrating an optical mechanism, the optical mechanism comprising a plurality of regularly arranged optical lenses, the optical lenses projecting a calibration image to a calibration ruler, moving the calibration ruler to a field of view area of a positioning mechanism, moving the positioning camera through a moving mechanism of the positioning mechanism, sequentially acquiring position information of the calibration image, and calibrating the optical lenses according to the position information of the calibration image. In the process of calibrating the optical lenses, the X direction is calibrated through the movement of the moving mechanism, and the substrate platform is fixed and does not introduce expansion error of the substrate platform.

Description

Technical Field

[0001] This invention relates to the field of direct-write exposure technology, and more specifically to a calibration method for an optical mechanism. Background Technology

[0002] Photolithography is widely used in semiconductor and PCB manufacturing, and is one of the process steps in producing semiconductor devices, chips, and PCB products. It is used to print feature patterns on a substrate surface to ultimately obtain the pattern structure required by the circuit design. Traditional photolithography requires the creation of a master mask or film for exposure, resulting in a long production cycle, and each mask corresponds to a single pattern, limiting its widespread application. To address the problems of traditional exposure technology, direct-write exposure mechanisms have emerged. These mechanisms utilize digital light processing technology and programmable digital mirror devices to edit different desired pattern structures, enabling rapid pattern switching. This not only reduces costs but also shortens process time, and is now widely used in the field of photolithography.

[0003] Direct-write exposure machines typically include a substrate platform, an alignment mechanism, and an exposure mechanism. The alignment and exposure mechanisms are positioned above the moving platform. Through the cooperation of the substrate platform, alignment mechanism, and exposure mechanism, the exposure operation on the substrate on the substrate platform is achieved. Direct-write exposure machines are high-precision machines. Before being put into use, the moving platform, alignment mechanism, and exposure mechanism need to be calibrated to determine their relative positions and improve the accuracy of machine operation. Existing methods for calibrating optical lenses involve exposing the optical lens to marked points on a scale, fixing the position of the alignment camera in the alignment mechanism, and then moving the scale below the alignment camera by moving the substrate platform. This movement of the substrate platform causes the center of the marked points on the scale to sequentially move to the center of the alignment camera, thus calibrating the positional relationship between adjacent optical lenses. However, this method, which calibrates the positional relationship of the optical lenses by moving the substrate platform, is prone to introducing errors from the substrate platform itself, resulting in errors in the optical lens calibration. Summary of the Invention

[0004] To address the above problems, the present invention provides a method for reducing the impact of substrate platform errors on optical mechanism calibration.

[0005] The technical solution is as follows: a calibration method for an optical mechanism, the optical mechanism including multiple regularly arranged optical lenses, the optical lenses project calibration images onto a calibration ruler, the calibration ruler is moved to the field of view of a alignment mechanism, the alignment camera is moved by the moving mechanism of the alignment mechanism, the position information of the calibration images is acquired sequentially, and the optical lenses are calibrated according to the position information of the calibration images.

[0006] Furthermore, before calibrating the optical lens, the alignment mechanism is calibrated by using the calibration ruler to calibrate the sub-scanning direction of the alignment mechanism.

[0007] Furthermore, the alignment mechanism is calibrated in the scanning direction using a calibration plate.

[0008] Furthermore, the optical lenses are arranged in multiple rows and columns, with the sub-scanning direction as the row and the scanning direction as the column, and the optical lenses in adjacent rows are staggered.

[0009] Furthermore, the calibration plate is moved to the field of view of the optical lens, and the calibration plate is moved by the motion mechanism to expose the calibration image to the calibration ruler line by line.

[0010] Furthermore, the calibration ruler is moved to the field of view of the alignment camera, and the alignment camera is moved to sequentially capture the calibration images to obtain the position of the calibration images and obtain the relative positional relationship between the optical lenses.

[0011] Furthermore, a reference lens is set in each row of the optical lenses. The relative positional relationship between the optical lenses in each row is obtained through the reference lens. Then, the relative positional relationship between the reference lenses in different rows is obtained through the reference lenses in different rows, thus obtaining the two-dimensional positional relationship of the optical lenses.

[0012] Furthermore, the calibration ruler is made of quartz material.

[0013] Furthermore, the calibration ruler uses a photosensitive material that gradually fades after being exposed to light.

[0014] Furthermore, the internal temperature of the direct-write exposure machine is kept constant through a temperature control system.

[0015] In the above calibration method, both the alignment camera and the substrate platform are calibrated based on the calibration board, which will not introduce the error of the substrate platform into the calibration of the alignment camera, resulting in more accurate results.

[0016] Compared to existing technologies, in the optical lens calibration process, the X-axis positional relationship is calibrated by the movement of the moving mechanism, while the base plate platform remains stationary, eliminating the introduction of expansion and contraction errors. Furthermore, the alignment camera generates less heat, minimizing its impact on the position measurement mechanism within the moving mechanism, resulting in no significant expansion or contraction changes and easier acquisition of accurate data. The accuracy of the moving mechanism within the alignment system is also calibrated using calibration ruler 6, maintaining the repeatability and consistency of the lens positional relationship calibration. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a direct-write exposure machine.

[0018] Figure 2 This is a schematic diagram of the positioning camera calibration plate.

[0019] Figure 3 This is a schematic diagram of the calibration ruler.

[0020] Figure 4 This is a schematic diagram of the calibration ruler after the optical mechanism projects the calibration image.

[0021] Figure 5 This is a schematic diagram of an embodiment of an optical mechanism.

[0022] Figure 6 This is a schematic diagram of a calibration ruler after the optical mechanism projects a calibration image in one embodiment. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0024] Research has revealed that the substrate platform is subject to expansion and contraction errors due to temperature and aging processes. To avoid these expansion and contraction errors from being introduced into optical lens calibration, this invention provides an optical lens calibration method, such as... Figure 1-6 As shown, a direct-write exposure machine includes a substrate platform 1 for placing a substrate, a motion mechanism 2 for driving the substrate platform 1 to move in multiple directions, an alignment mechanism 3 for acquiring the position information of the substrate placed on the substrate platform 1, an optical mechanism 4 for image projection, and a temperature control system for controlling the internal temperature of the direct-write exposure machine to maintain a constant internal temperature. The motion mechanism 2 includes an X-direction motion mechanism, a Y-direction motion mechanism, and a Z-direction motion mechanism, which respectively drive the substrate platform to move in the X, Y, and Z directions. The Y direction is the scanning direction of the direct-write exposure machine, the X direction is perpendicular to the Y direction and is the secondary scanning direction of the direct-write exposure machine, and the Z direction is perpendicular to the XY plane. The alignment mechanism 3 includes an alignment camera 30 and a moving mechanism 31 for driving the alignment camera to slide along the X direction. Preferably, a linear motor is used as the drive motor for the motion mechanism. The motion mechanism may also include only the Y-direction and Z-direction motion mechanisms, excluding the X-direction motion mechanism. The optical mechanism 4 includes multiple optical lenses 40 arranged in a regular pattern.

[0025] Before calibrating the optical lens, the substrate platform and the alignment camera must be calibrated first. The accuracy, straightness, and orthogonality compensation data of the substrate platform are obtained by calibrating the substrate platform, and the two-dimensional positional relationship of the alignment camera is obtained by calibrating the alignment camera.

[0026] Calibration of the substrate platform typically employs a calibration plate 5, which has an array of calibration points 50 arranged regularly along the X and Y directions. In the X direction, the first interval between adjacent calibration points is L1, and in the Y direction, the second interval between adjacent calibration points is L2. When calibrating the substrate platform 1, the calibration plate 5 is placed on the substrate platform 1, and the position of the alignment camera 30 is adjusted corresponding to the calibration points 50 on the calibration plate 5. The position of the alignment camera 30 is fixed, and the Y-direction motion mechanism moves the substrate platform 1, causing the calibration plate 5 to move along the Y direction. Each movement interval is a second interval distance L2, or an integer multiple of the second interval distance L2. Each time the calibration plate 5 moves a position, the alignment camera 30 acquires measurement data. Finally, the measurement data in the Y direction of the motion mechanism is acquired, which represents the Y-direction motion data of the substrate platform. Then, the X-direction movement mechanism drives the base plate platform 1 to move, and the base plate platform 1 drives the calibration plate to move along the X-direction by a first interval distance L1, or a multiple of the first interval distance L1. Similarly, the Y-direction movement mechanism drives the base plate platform 1 to move, and the base plate platform 1 drives the calibration plate 5 to move along the Y-direction. Each movement interval is the same as the aforementioned interval distance, which is a second interval distance, or a multiple of the second interval distance. Each time the calibration plate 5 moves to a position, the alignment camera 30 acquires measurement data once, finally acquiring all measurement data in the X and Y directions of the movement mechanism. This process continues, with the base plate platform 1 driving the calibration plate 5 to move the same distance in the same direction each time, ultimately acquiring all the detection coordinate data of the calibration plate. Preferably, the distance the calibration plate 5 moves along the X and Y directions is as small as possible to obtain more actual measurement data, thereby obtaining more accurate calibration data. Calibration data, i.e., compensation values, are calculated based on the detection data of the alignment camera 30 and the ideal coordinate values. The compensation values ​​can be calculated using conventional methods, such as linear equations or square root equations.

[0027] When calibrating the alignment camera 30, a combination of calibration plate 5 and calibration ruler 6 is used. For example... Figure 3 As shown, the calibration ruler 6 includes a projection image area 60 and a positioning point area 61. The positioning point area of ​​the calibration ruler has one-dimensionally set positioning points 62 for one-dimensional position calibration, specifically for calibration in the X direction of the direct-write exposure machine. The projection image area is provided with a photosensitive layer, and the optical lens projects the calibration image into the projection area. Preferably, the calibration ruler 6 is connected to the substrate platform. The calibration ruler 6 and the substrate platform can be fixedly connected or detachably connected. The alignment camera uses a calibration plate on the substrate platform for calibration in the Y direction. The photosensitive material of the calibration ruler can be a photosensitive material with a gradually fading function after exposure.

[0028] When calibrating the alignment camera in the X direction, the alignment camera 30 is moved to its respective zero point, and the calibration ruler 6 is moved below the alignment camera 30, so that the alignment camera 30 can perform data detection on the positioning point 62 on the calibration ruler 6.

[0029] The alignment camera 30 is moved to detect data in the X direction at the positioning points 62 on the calibration ruler 6. The alignment camera 30 is moved along the X direction to sequentially capture data from the positioning points 62 on the calibration ruler. The actual measured values ​​of the alignment camera 30's movement in the X direction are obtained. Calibration data for the alignment camera 30's movement in the X direction is obtained based on the actual measured data and the ideal data.

[0030] For each position the alignment camera 30 moves in the X direction, the Y-direction motion mechanism drives the substrate platform 1 to move, causing the calibration plate 5 to move in the Y direction. Each movement interval is a second interval distance L2, or an integer multiple of the second interval distance L2. For each position the calibration plate 5 moves, the alignment camera 30 acquires measurement data. Finally, the measurement data in the Y direction of the motion mechanism is acquired, i.e., the relative motion data of the alignment camera 30 in the Y direction. Calibration data for the Y-direction movement of the alignment camera 30 is obtained based on the measurement data and ideal data. This calibration data can be obtained using the same calculation method as the substrate platform calibration data, such as using linear equations or square root equations.

[0031] A two-dimensional compensation value chart of the movement of the alignment camera 30 is obtained using the calibration data in the X and Y directions of the alignment camera 30.

[0032] The relative movement data of the alignment camera 30 in the Y direction is used to obtain calibration data of the alignment camera 30 in the Y direction based on the data after calibration on the substrate platform 1, and a two-dimensional compensation value chart of the movement of the alignment camera 30 is obtained.

[0033] When there are more than two alignment cameras 30, the relative positional relationship between the alignment cameras 30 is obtained by the alignment cameras 30 capturing data from the same calibration point. One alignment camera 30 is designated as the reference alignment camera. Using the reference alignment camera as a reference, the reference alignment camera and the remaining alignment cameras are moved to their respective zero points. By moving the other alignment cameras and the reference alignment camera to capture at least one calibration point on the calibration plate, data from all alignment cameras 30 are obtained. The positional relationship between the remaining alignment cameras and the reference alignment camera is then obtained based on the actual measurement data.

[0034] After calibrating the aforementioned substrate platform and alignment camera, the optical lens is calibrated, such as... Figure 4As shown, the calibration ruler 6 is moved below the optical lens, and the optical lens projects a calibration image 63 onto the calibration ruler 6. Then, the calibration ruler 6 is moved into the field of view of the alignment camera. The alignment camera is adjusted in the X direction by the moving mechanism 31, and the calibration plate is adjusted in the Y direction by the motion mechanism 2, so that the calibration image is located at the center of the field of view of the alignment camera 30, and the position of the calibration image 63 is obtained. The position of the optical lens is calibrated according to the position of the calibration image 63.

[0035] The calibration plate and calibration ruler 6 are preferably made of a material that is not easily expanded or contracted, such as quartz.

[0036] The optical mechanism comprises multiple optical lenses arranged sequentially in the X direction. When the calibration ruler 6 moves below the optical mechanism, the multiple optical lenses simultaneously project calibration images onto the calibration ruler 6. After obtaining the calibration image on the calibration ruler 6, the calibration ruler 6 moves into the field of view of the alignment mechanism. The moving mechanism moves the alignment camera sequentially to the position of the calibration image 63. Through minor adjustments, the calibration image 63 is positioned at the center of the field of view of the alignment camera 30, thus obtaining the position information of the calibration image 63. The position information of the optical lenses is then calibrated based on the position information of the calibration image 63. The relative position information of the optical lenses in the X direction is obtained through the position information of the optical lenses in the X direction. By setting a reference optical lens, the relative positional relationship between the remaining optical lenses and the reference optical lens is obtained. The reference optical lens can be selected from optical lenses located at the edge.

[0037] like Figure 5-6 As shown, the optical mechanism comprises multiple optical lenses arranged in multiple rows and columns, with the sub-scanning direction as the row and the scanning direction as the column. Optical lenses in adjacent rows are staggered, meaning they are offset in the column direction rather than aligned. Typically, the optical lenses in one row are positioned between two optical lenses in another row. The projection area in the calibration ruler 6 corresponds to the number of optical lenses and can project multiple rows of calibration images. During image calibration, the calibration ruler 6 moves below one row of optical lenses, and the optical lenses project calibration images onto the calibration ruler 6, completing the projection of one row of optical lenses. Then, the motion mechanism moves the calibration ruler 6 to the next row of optical lenses, completing the projection of the second row of optical lenses. The projections of the two rows of optical lenses are located at different positions on the calibration ruler 6, and so on. By moving the calibration ruler 6 through the motion mechanism, the operation of projecting calibration images onto the calibration ruler 6 is completed.

[0038] The calibration ruler 6 is moved to the field of view of the alignment mechanism, and the alignment camera 30 is moved to sequentially capture the calibration images 63. If the calibration image 63 is not located at the center of the field of view of the alignment camera 30, the alignment camera can be moved in the X direction by the moving mechanism and / or the calibration ruler 6 can be moved in the Y direction by the motion mechanism 2 to obtain the position of the calibration image 63, thus obtaining the positional relationship between a row of optical lenses. A reference lens is set in each row of optical lenses. The positional relationship between the optical lenses in each row is obtained through the reference lens. Then, the relative positional relationship between reference lenses in different rows is obtained through the position data of the reference lens, thereby obtaining the relative positional relationship between the optical lenses in the optical mechanism.

[0039] The calibration image on the calibration ruler can be obtained using the method described above: first, obtain calibration images from all different rows, and then obtain the position of calibration image 63. Alternatively, one can first obtain calibration images from one row of optical lenses, then calibrate the position of the obtained calibration images, and then obtain calibration images from another row of optical lenses, calibrating the position of the obtained calibration images. Based on the position of each row of reference optical lenses, the relative positional relationship of the reference optical lenses in different rows is obtained. This leads to the relative positional relationship between the optical lenses in the optical mechanism.

[0040] During the calibration of the optical lens, the positional relationship is calibrated in the X direction through the movement of the moving mechanism, while the base plate platform remains stationary, thus avoiding any expansion or contraction errors. Simultaneously, the alignment camera generates relatively little heat, minimizing its impact on the position measurement mechanism within the moving mechanism, resulting in no significant expansion or contraction changes and facilitating the acquisition of accurate data. Furthermore, the accuracy of the moving mechanism within the alignment mechanism is also calibrated using calibration ruler 6, maintaining the repeatability and consistency of the lens positional relationship calibration.

Claims

1. A calibration method for an optical mechanism, characterized in that: The optical mechanism includes multiple regularly arranged optical lenses. Before calibrating the optical lenses, the alignment camera is calibrated first. During alignment calibration, a combination of a calibration plate and a calibration ruler is used. The calibration ruler includes a projection image area and a positioning point area. The positioning point area of ​​the calibration ruler has one-dimensionally set positioning points. The calibration ruler is used to calibrate the sub-scanning direction of the alignment mechanism, and the calibration plate is used to calibrate the scanning direction of the alignment mechanism. The optical lenses project the calibration image onto the calibration ruler, and the calibration ruler is moved to the field of view of the alignment mechanism. The alignment mechanism then... The moving mechanism moves the alignment camera and sequentially acquires the position information of the calibration images. The optical lenses are calibrated based on the position information of the calibration images. The optical lenses are arranged in multiple rows and columns, with the sub-scanning direction as the row and the scanning direction as the column. The optical lenses in adjacent rows are staggered. A reference lens is set in each row of the optical lenses. The relative positional relationship between the optical lenses in each row is obtained through the reference lens. Then, the relative positional relationship between the reference lenses in different rows is obtained through the reference lenses in different rows, thus obtaining the two-dimensional positional relationship of the optical lenses.

2. The calibration method for an optical mechanism according to claim 1, characterized in that: The calibration ruler is moved to the field of view of the optical lens, and the calibration ruler is moved by the motion mechanism to expose the calibration image line by line to the calibration ruler.

3. The calibration method for the optical mechanism according to claim 2, characterized in that: Move the calibration ruler to the field of view of the alignment camera, and take pictures of the calibration images in sequence by moving the alignment camera to obtain the position of the calibration images and obtain the relative positional relationship between the optical lenses.

4. The calibration method for an optical mechanism according to claim 1, characterized in that... The calibration ruler is made of quartz material.

5. The calibration method for an optical mechanism according to claim 1, characterized in that: The calibration ruler uses a photosensitive material that gradually fades after exposure to light.

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