A method for detecting exposure anomaly in laser direct writing system

Abstract

The present invention relates to an exposure abnormality detection method for a laser direct writing system, wherein the laser direct writing system is provided with an exposure area and a detection area, wherein the exposure area is used to expose a workpiece image, and the detection area is used to expose a detection image, wherein a marking point is provided in the detection area, and the detection image is exposed in alignment according to the marking point, and data information of the exposure detection image after exposure is obtained, and the exposure abnormality of the laser direct writing system is detected according to the data information of the exposure detection image. By using the detection area to expose the detection image, it is convenient to timely detect whether there is an abnormality in the laser direct writing system, timely handle workpieces with unqualified exposure, reduce the outflow of abnormal boards, and timely correct problems existing in the laser direct writing system, so as to avoid the generation of abnormal boards and effectively reduce losses.

Description

Technical Field

[0001] The invention relates to the technical field of laser direct writing, and in particular to a self-checking method in the field of laser direct writing. Background Art

[0002] The laser direct writing exposure system, also known as the direct image projection system, can be applied to the research and development and production of semiconductors, PCBs and planar imaging. Its principle is to use a graphic generator to replace the traditional mask technology and directly expose the computer's graphic data to the product, which can save costs and improve efficiency.

[0003] The commonly used pattern generators in laser direct writing exposure systems are digital micromirror arrays (DMD), liquid crystal displays, rotating polygonal mirror scanners or grating light valves (GLV). When the laser direct writing system exposes the workpiece, the workpiece is covered with photoresist. By controlling the image generator, according to the image to be exposed, part of the light irradiates the workpiece, and part of the light deviates from the workpiece and is emitted, so as to obtain the required exposure image on the workpiece. Before exposure, the workpiece needs to be aligned so that the exposure image is correctly projected to the corresponding position of the workpiece. During the exposure process, if the control of the pattern generator is abnormal or there is a deviation in the alignment process, it will cause major defects in the exposure result. If the exposure result is not monitored in time, the problematic workpiece will be transferred to the subsequent process for the next step of processing. The problematic workpiece can only be scrapped in the end. In addition, if the system abnormality is not discovered and persists, the exposure of new workpieces will continue, which will eventually cause irreparable losses. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an exposure abnormality detection device and method suitable for a laser direct writing system.

[0005] In order to solve the above problems, the present invention provides an exposure abnormality detection method for a laser direct writing system, wherein the laser direct writing system is provided with an exposure area and a detection area, the exposure area is used to expose the workpiece image, and the detection area is used to expose the detection image, the detection area is provided with marking points, and the detection image is exposed in a positional manner according to the marking points, and data information of the exposure detection image after exposure is obtained, and exposure abnormality of the laser direct writing system is detected according to the data information of the exposure detection image.

[0006] Furthermore, the data information of the exposure detection image includes position information, and whether there is a deviation in the alignment of the laser direct writing system is detected based on the position information of the exposure detection image.

[0007] Furthermore, the data information of the exposure detection image includes image integrity information, and whether the control of the pattern generator of the laser direct writing system is abnormal is detected based on the image integrity information of the exposure detection image.

[0008] Furthermore, the detection image exposure is performed multiple times at the same position area of ​​the detection area, and the detection image exposed each time is different.

[0009] Furthermore, the detection images exposed in the same position area of ​​the detection area have different shapes or sizes.

[0010] Furthermore, the detection images exposed in the same position area of ​​the detection area have the same center position.

[0011] Furthermore, the photosensitive material in the detection area can display a detection image after exposure, and after a period of time, the portion displaying the detection image returns to an initial state.

[0012] Furthermore, the workpiece image of the exposure area and the detection image of the detection area are aligned and integrated into exposure image data, and are correspondingly split into exposure strips according to the exposure image data. The exposure area and the detection area are subjected to strip exposure, and each exposure strip contains graphic data of the detection image.

[0013] Furthermore, the detection image includes a feature image, and the feature pattern is formed by exposing and splicing two adjacent strips.

[0014] The laser direct writing system of the above-mentioned exposure abnormality detection method includes an optical mechanism, an image acquisition mechanism, and a platform mechanism. The platform mechanism is used to carry a workpiece, and the platform mechanism drives the workpiece to move to the image acquisition mechanism for alignment detection operation. The platform mechanism drives the workpiece to move to the optical mechanism for exposure operation. The platform mechanism includes a table, a detection scale and a motion mechanism. The motion mechanism drives the table and the detection scale to move. The detection scale is provided with marking points for detecting image alignment.

[0015] Furthermore, the detection scale includes a calibration area and a detection area, and the detection area is adjacent to the table.

[0016] Furthermore, the detection scale is provided with positioning points, and the positioning points are used as marking points to align the detection image.

[0017] Furthermore, the optical mechanism includes a first group of optical lenses and a second group of optical lenses, the first group of optical lenses and the second group of optical lenses are arranged at intervals in the scanning direction, and the detection scale is arranged on opposite sides of the table.

[0018] Compared with the existing technology, the detection area is used to expose the detection image, which is convenient for timely detection of whether there is any abnormality in the laser direct writing system, timely processing of workpieces with unqualified exposure, reducing the outflow of abnormal boards, and timely correcting problems in the laser direct writing system to avoid the production of abnormal boards and effectively reduce losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of an exposure area and a detection area of ​​an embodiment of a laser direct writing system.

[0020] Figure 2 It is a schematic diagram of the exposure area and the detection area of ​​another embodiment of the laser direct writing system.

[0021] Figure 3 It is a schematic diagram of the graphics processing of the laser direct writing system.

[0022] Figure 4 This is the first implementation method of detecting an image.

[0023] Figure 5 This is the second implementation method of detecting the image.

[0024] Figure 6 This is a schematic diagram of the detection image exposure process Figure 1 .

[0025] Figure 7 This is a schematic diagram of the detection image exposure process Figure 2 .

[0026] Figure 8 It is a schematic diagram of the center of the marking point and the center of the exposure detection image.

[0027] Fig. 9 It is a schematic diagram of the exposure characteristic image.

[0028] Fig.10 It is a schematic diagram of obtaining exposure detection image Figure 1 .

[0029] Fig.11 It is a schematic diagram of obtaining exposure detection image Figure 2 .

[0030] Fig.12 Schematic diagram of a first embodiment of a laser direct writing system.

[0031] Fig.13 2 is a schematic diagram of a second embodiment of a laser direct writing system.

[0032] Fig.14 2 is a schematic diagram of an embodiment of a detection scale. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described below by means of specific embodiments shown in the accompanying drawings.

[0034] The present invention relates to a method for detecting exposure anomaly of a laser direct writing system. Figure 1-2 As shown, the laser direct writing system is correspondingly provided with an exposure area 1 and a detection area 2. The exposure area 1 is used to expose the image of the workpiece, and the detection area 2 is used to detect exposure abnormalities. By exposing the detection image in the detection area 2, the detection image after exposure is detected and analyzed to determine whether there is an exposure abnormality. Preferably, the detection area 2 is in the shape of a strip, which is arranged on one side or two opposite sides of the exposure area 1 and extends perpendicular to the scanning direction of the laser direct writing system. The detection area 2 is adjacent to the exposure area 1, shortening the length of the exposure strip and improving the exposure efficiency.

[0035] The workpiece placed in the exposure area is provided with alignment points, and the detection area is provided with marking points 20, through which the image to be exposed of the workpiece is aligned, and through which the detection image is aligned. Figure 3 As shown, the image to be exposed corresponding to the workpiece and the detection image to be exposed corresponding to the detection area are adjusted respectively according to the alignment result to obtain workpiece image data and detection image data. The workpiece image data and the detection image data are integrated into exposure image data, and images are exposed in the exposure area and the detection area according to the exposure image data. When performing exposure scanning according to the exposure image data, the exposure image data is split into multiple strip data for exposure operation. In the laser direct writing system, a single optical lens scans and exposes in the scanning direction once to form an exposure strip, and the strip data includes at least one detection image data, and each exposure strip forms at least one exposure detection image corresponding to the exposure strip in the detection area.

[0036] like Figure 4-7 As shown, the detection image can be a regular image, such as a circle, square, rectangle, circular array, stripe array and other graphics. The circular array means that the edge of the graphic is obtained by regularly arranging circles of equal size, and the stripe array means a graphic obtained by regularly arranging rectangles, such as a rectangular array arrangement, a parallel arrangement and / or a vertical arrangement; the exposure detection image can also use irregular graphics, such as irregular polygons and irregular curves.

[0037] When exposing the detection image of the same area of ​​the detection area, the detection image of the same area is exposed by setting different detection images. For example, when the detection area is exposed for the first time, the detection image is a circle, and the exposure detection image 21 is a circle; when the same area of ​​the detection area is exposed for the second time, the exposure detection image 21 is a square, and the square has no intersection with the circle, or the side length of the square is the same as the diameter of the circle, and the centers of the circle and the square overlap. Of course, other graphics such as triangles, diamonds, etc. can also be used, which are located inside or outside the circle of the first exposure. The detection image is the image to be exposed, and the exposure detection image 21 is the image exposed to the detection area, and the exposure detection image corresponds to the detection image.

[0038] like Figure 6-7 As shown, the detection image may also adopt the same kind of graphics, and when the same area is exposed at different times, the image size is different. For example, if the detection image is a circle, when it is exposed in the detection area for the first time, the circle radius of the exposed detection image is R1, and when it is exposed in the same area of ​​the detection area for the second time, the circle radius of the exposed detection image is R2, and R2 may be greater than R1 or less than R1. Preferably, the detection images exposed twice are circles with different radii, but the positions of the centers of the circles are the same. When the detection image is exposed in the detection area multiple times, the size of the detection image is gradually increased or decreased at equal intervals, so that the detection image is exposed at the same position in the detection area at different times. For example, at the first moment, the exposed detection image is a circle with a radius of R1; at the second moment, the detection image exposed in the same position area is a circle with a radius of R2; at the third moment, the detection image exposed in the same position area is a circle with a radius of R3, then the radius difference R of the detection images exposed in the same position area of ​​the detection area at adjacent moments is 差 =R3-R2=R2-R1, R 差 It can be a positive number or a negative number. For the detection image at the Nth moment, the circular radius RN = R (N-1) + R 差 The detection image is not limited to a circle, but may also be a square, rectangle, circle, triangle, parallelogram or other shapes. By changing the side length of the shape at equal intervals, exposure detection images exposed to the same position of the detection area at different times are obtained. The exposure detection images at different times have a common center, and different sizes are overlapped without interfering with each other.

[0039] The photosensitive material of the detection area can be selected to have a photosensitive material that can be exposed multiple times. The color of the exposed area and the unexposed area of ​​the photosensitive material are different. After a period of time, the color of the exposed area changes to the color of the unexposed area, and can be exposed again to further improve the utilization rate of the detection area.

[0040] By using photosensitive materials that can be exposed multiple times and / or using different detection images, the detection area can be reused to improve the utilization rate of the detection area. The different detection images include detection images with different graphics, or detection images with the same graphics but different sizes.

[0041] After the detection image is exposed in the detection area, the image data of the detection area is obtained through the image detection device and the obtained image is analyzed, so as to know the exposure effect of the laser direct writing system. By analyzing the integrity of the image of the detection area, it is known whether there are redundant line graphics or missing line graphics during the exposure process, and then whether there are problems with the pattern generator during the exposure process. Through the position of the detection image, it is known whether there is a deviation in the alignment, and then it is evaluated whether the hardware accuracy of the laser direct writing system has changed and whether it meets the accuracy requirements.

[0042] The method to determine whether there is a deviation in alignment can be the center comparison method. Figure 8 As shown, the image acquisition device acquires the position of the center 22 of the detection area mark point and the position of the exposure detection image center 23, compares whether there is a deviation between the two center positions, determines whether there is a deviation in the alignment, and then monitors whether the hardware device of the laser direct writing system has changed in accuracy. If the two centers are coincident or substantially coincident, and meet the requirements of the alignment accuracy, then there is no deviation in the alignment; if there is a large distance between the two centers, then there is a deviation in the alignment accuracy, and the relevant hardware devices of the laser direct writing system need to be calibrated. Preferably, the detection image selects a regular image, such as a circle, rectangle, square, triangle, and other regular polygons.

[0043] The image detection device includes an image acquisition device and an image analysis system. The image acquisition device is used to acquire an exposure detection image in the detection area and transmit the exposure detection image data to the image analysis system. The image analysis system analyzes the exposure detection image data to determine whether there is an exposure defect in the laser direct writing system. According to whether there is an exposure defect in the laser direct writing system and whether the severity of the exposure defect affects the subsequent process, it is determined whether the exposed workpiece needs to be recycled or flowed into the next process. According to whether there is a position deviation in the laser direct writing system, it is determined whether the hardware of the laser direct writing system needs to be calibrated.

[0044] On this basis, the splicing effect of the laser direct writing system is further tested, such as Fig. 9As shown, in the detection images corresponding to adjacent strips, at the strip joint, the detection images exposed successively respectively contain a part of the specific image 24, and the partial specific images in the adjacent detection images are spliced ​​into a complete feature image, and the specific image can be a circle, a square, a straight line, a curve, etc. By acquiring the specific image and judging the splicing effect of the specific image, the splicing effect of the exposure image can be obtained.

[0045] like Figure 10-11 As shown, the number of image acquisition devices 30 of the image detection device is the same as the number of strips exposed simultaneously by the laser direct writing system. For one exposure strip of the laser direct writing system, the corresponding detection image is exposed in the detection area, and the corresponding workpiece image is exposed in the exposure area. The workpiece image can be exposed in the exposure area first, and then the detection image can be exposed in the detection area after the workpiece image exposure is completed; the detection image can also be exposed in the detection area first, and then the workpiece image can be exposed in the exposure area; the detection image can also be interspersed in the workpiece image, for example: it is applied to the case of exposing multiple workpieces at one time. According to the position of the detection image, before the next strip is exposed or during the exposure of the next strip, before the detection image moves to the image acquisition position of the image acquisition device, the image acquisition device 30 is moved to the position of the detection image corresponding to the previous strip to acquire the exposure detection image. For example, the first strip is exposed in the exposure area, and the first detection image corresponding to the first strip is exposed in the detection area, forming a first exposure detection image 200 in the detection area; the workpiece is moved to expose the second strip, and the image acquisition device 30 is moved to the position corresponding to the first exposure detection image, and while the second strip is exposed, the image acquisition device 30 acquires the image data of the first exposure detection image 200 corresponding to the first strip; the workpiece is moved to expose the third strip, and at this time, the image acquisition device moves to the position corresponding to the second exposure detection image 201, and acquires the image data of the second exposure detection image 201 corresponding to the second strip. When performing the exposure operation of the workpiece image, the data information of the exposure detection image is acquired synchronously. The two operations are performed simultaneously, and the time burden of workpiece processing will not be increased due to the operation of exposure effect detection.

[0046] A laser direct writing system corresponding to an embodiment of the above-mentioned exposure effect detection method, such as Fig.12 As shown, the laser direct writing system includes an optical mechanism 400, an image acquisition mechanism 500, and a platform mechanism 600. The platform mechanism 600 is used to carry the workpiece, and the platform mechanism 600 drives the workpiece to move to the image acquisition mechanism 500 for alignment detection operation, and the platform mechanism 600 drives the workpiece to move to the optical mechanism 400 for exposure operation.

[0047] The platform mechanism includes a table 601, a detection scale 602 and a motion mechanism, and the motion mechanism drives the table 601 and the detection scale 602 to move. The detection scale 602 is arranged on one side of the table 601 or on both sides of the table 601, and the detection scale 602 is perpendicular to the scanning motion direction of the table.

[0048] like Fig.13 The detection scale 602 includes a calibration area 603 and a detection area 604. The calibration area 603 includes a positioning point 605 for calibrating the camera position relationship, the lens position relationship, etc., and the detection area 604 includes a marking point 606 for exposing the detection image. The calibration area and the detection area are divided, and the detection area is placed close to the table, so as to shorten the length of the exposure strip and improve the efficiency of exposure.

[0049] The calibration area 603 and the detection area 604 may also be shared, that is, the positioning point 605 of the calibration area 603 is used as a marking point for alignment, and the detection image is exposed according to the marking point.

[0050] like Fig.14 As shown, another embodiment of the laser direct writing system includes an optical mechanism 700, an image acquisition mechanism 800, and a platform mechanism 900. The platform mechanism 900 includes a table 901, a detection scale 902, and a motion mechanism. The optical mechanism 700 includes a plurality of optical lenses 701, and the optical lenses 701 are arranged in two rows, respectively constituting a first group of optical lenses 702 and a second group of optical lenses 703, and each row of optical lenses 701 exposes at least one-half of the table area. The detection scale 902 is arranged on both sides of the table 901, and detects exposure anomalies of the first group of optical lenses 702 or the second group of optical lenses 703 in the corresponding area. The detection scale also includes a calibration area and a detection area, and the specific configuration is as described above.

[0051] The exposure detection image on the detection scale can be obtained after the exposure operation is completed, or as mentioned above, the image acquisition device for acquiring the exposure detection image is arranged adjacent to the optical mechanism to facilitate the acquisition of the exposure detection image during the exposure operation.

[0052] The image acquisition device for acquiring the workpiece alignment point, the image acquisition device for acquiring the detection area marking point, and the image acquisition device for acquiring the exposure detection image in the image acquisition mechanism (500, 800) can use the same image acquisition device, or can be separately provided according to different functions.

Claims

1. A method for detecting exposure anomaly in a laser direct writing system, characterized in that: The laser direct writing system is provided with an exposure area and a detection area, the exposure area is used to expose the workpiece image, and the detection area is used to expose the detection image. The detection area is provided with marking points, the detection image is aligned through the marking points, and the image to be exposed is aligned through the alignment points of the workpiece. According to the alignment results, the image to be exposed corresponding to the workpiece and the detection image to be exposed corresponding to the detection area are adjusted respectively to obtain workpiece image data and detection image data. The workpiece image data and the detection image data are integrated into exposure image data, and images are exposed in the exposure area and the detection area according to the exposure image data, and data information of the exposure detection image after exposure is obtained. According to the data information of the exposure detection image, exposure abnormality of the laser direct writing system is detected.

2. The method for detecting exposure anomaly of a laser direct writing system according to claim 1, characterized in that: The data information of the exposure detection image includes position information. According to the acquired position of the center of the detection area mark point and the center of the exposure detection image, the two center positions are compared to determine whether there is a deviation in the alignment.

3. The method for detecting exposure anomaly of a laser direct writing system according to claim 1, characterized in that: The data information of the exposure detection image includes image integrity information, and whether the control of the pattern generator of the laser direct writing system is abnormal is detected according to the image integrity information of the exposure detection image.

4. The method for detecting exposure anomaly of a laser direct writing system according to claim 1, characterized in that: The same position area of ​​the detection area is exposed for multiple times, and the detection image is different each time.

5. The method for detecting exposure anomaly of a laser direct writing system according to claim 4, characterized in that: The detection images exposed in the same position area of ​​the detection area have different shapes or sizes.

6. The method for detecting exposure anomaly of a laser direct writing system according to claim 5, characterized in that: The detection images exposed in the same position area of ​​the detection area have the same center position.

7. The method for detecting exposure anomaly of a laser direct writing system according to claim 1, characterized in that: The photosensitive material in the detection area can display a detection image after exposure, and after a period of time, the part displaying the detection image returns to an initial state.

8. The method for detecting exposure anomaly of a laser direct writing system according to claim 1, characterized in that: The exposure image data is split into exposure strips, and strip exposure is performed on the exposure area and the detection area, and each exposure strip contains graphic data of the detection image.

9. The method for detecting exposure anomaly of a laser direct writing system according to claim 8, characterized in that: The detection image includes a feature image, and the feature image is formed by exposing and splicing two adjacent strips.

10. A laser direct writing system using any exposure abnormality detection method according to any one of claims 1 to 9, characterized in that: The laser direct writing system includes an optical mechanism, an image acquisition mechanism, and a platform mechanism. The platform mechanism is used to carry a workpiece. The platform mechanism drives the workpiece to move to the image acquisition mechanism for alignment detection operation. The platform mechanism drives the workpiece to move to the optical mechanism for exposure operation. The platform mechanism includes a table, a detection scale and a motion mechanism. The motion mechanism drives the table and the detection scale to move. The detection scale is provided with marking points for detecting image alignment.

11. The laser direct writing system according to claim 10, characterized in that: The detection scale includes a calibration area and a detection area, and the detection area is adjacent to the table.

12. The laser direct writing system according to claim 10, characterized in that: The detection scale is provided with positioning points, and the positioning points are used as marking points to align the detection image.

13. The laser direct writing system according to claim 10, characterized in that: The optical mechanism comprises a first group of optical lenses and a second group of optical lenses, the first group of optical lenses and the second group of optical lenses are arranged at intervals in the scanning direction, and the detection scale is arranged on two opposite sides of the table.

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