Exposure system for processing batch substrates for double-sided exposure
By acquiring and storing image markers as template images during substrate processing, and using index numbers to retrieve corresponding template images for alignment and exposure, the problem of template image mismatch in batch substrate double-sided exposure is solved, and efficient alignment and exposure operations are achieved.
Patent Information
- Application Number
- CN202511084634.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2021-09-30
- Publication Date
- 2025-09-19
AI Technical Summary
In the prior art, during the double-sided exposure process of batch substrates, mismatched template images lead to alignment failures, making it impossible to effectively perform batch processing.
By obtaining the image marking points on the back of the substrate as a template image at the first workstation, the index number is stored according to the processing order of the substrate, the substrate is transferred to the second workstation using the transmission system, and the corresponding template image is retrieved by the index number for alignment and exposure.
It achieves accurate alignment and exposure during the double-sided exposure process of batch substrates, avoids template image matching errors, and improves processing accuracy and efficiency.
Smart Images
Figure CN120669487A_ABST
Abstract
Description
[0001] This application is a divisional application. The original application number is 2021111610720. The name of the invention is “A method and system for double-sided exposure of batch substrates”. The application date is September 30, 2021. Technical Field
[0002] The present invention relates to the field of laser processing, and in particular to a method and system for double-sided exposure of the front and back sides of a substrate. Background Art
[0003] Exposure technology is widely used in the field of semiconductor and PCB production. It is one of the process steps in manufacturing semiconductor devices, chips, PCB boards and other products. It is used to print characteristic patterns on the surface of the substrate, and finally obtain the graphic structure required by the circuit design. Traditional exposure technology requires the production of a master mask or film negative for exposure operation. The production cycle is long, and each version corresponds to a single graphic, which cannot be widely used. In order to solve the above problems of traditional exposure technology, direct-write exposure technology has emerged. It uses digital light processing technology and a programmable digital mirror device to edit different graphic structures. It can quickly switch graphics, which not only reduces costs, but also shortens the production cycle. It is being widely used in the field of exposure technology. The principle of direct-write exposure is to transfer the designed pattern to the surface of the substrate coated with a photosensitive material by modulating the light beam, and then through processes such as development and etching to finally obtain the desired graphic structure.
[0004] For printed circuit boards, multilayer boards are usually used. The multilayer boards need inner layers that can be connected on both sides. The inner layers do not only need to be exposed on one side, but also need to be exposed on both sides. When exposing the inner layer board, it is necessary to expose the front and back sides respectively, and at the same time, it is necessary to ensure that the positions of the graphics on the front and back sides of the inner layer board correspond. In the prior art, when exposing the first side graphics on the front side of the inner layer board, a marking device is usually used to form an alignment mark on the back side of the inner layer board. After the front side of the inner layer board is exposed, the back side of the inner layer board is placed upwards, and the alignment mark is captured by the alignment camera to calculate the precise printing position of the graphics to be drawn on the second side. The marking device needs to use a laser to form a mark on the back side of the inner layer board, but the energy of the laser is difficult to control, and the shape of the mark boundary is prone to change, making it difficult to accurately identify the boundary, resulting in reduced accuracy. In order to solve the above problem, an existing processing method is to set an image acquisition device on the back of the substrate, obtain a characteristic image of the back of the substrate through the image acquisition device, obtain a template image through the characteristic image, and when the back of the substrate is exposed, match the template image on the back of the substrate for alignment. However, when performing batch processing, the template image obtained for each substrate is different, and the corresponding template image needs to be obtained for alignment. Since a large number of template images need to be stored, confusion often occurs during batch processing, resulting in the inability to align. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to provide a method and system for processing batch substrates for double-sided exposure, so as to solve the problem of being unable to align due to mismatch of template images.
[0006] In order to solve the above problems, the present invention provides an exposure system for double-sided exposure of batch substrates, wherein the exposure system includes a first workstation, a second workstation and a transmission system between the first workstation and the second workstation, wherein the first workstation exposes the front side of the substrate, obtains image marking points on the back side of the substrate as a template image, stores the template image corresponding to the substrate by index number according to the processing sequence of the substrate, and obtains a retrieval sequence, and the transmission system transfers the substrate that has completed the front exposure at the first workstation to the second workstation, obtains the position of the index number corresponding to the current substrate in the retrieval sequence according to the processing sequence of the substrate, retrieves the template image corresponding to the current substrate by the obtained index number, and aligns and exposes the back side of the substrate.
[0007] In one embodiment, the position of the index number corresponding to the current substrate in the call sequence is obtained according to the processing order of the substrates, and is obtained by counting the call sequence during the batch processing process.
[0008] In one embodiment, for substrates that undergo exposure operation at the second station, the number of exposure operations or the number of unloading operations is used to count the call sequence. For substrates that do not undergo exposure operation at the second station, the number of unloading operations is used to count the call sequence.
[0009] In one embodiment, when two substrates are simultaneously subjected to alignment exposure operation at the first station and the second station, neither substrate can be subjected to exposure operation, and both substrates are simultaneously subjected to unloading operation and sequence counting is performed.
[0010] In one embodiment, when the first station and the second station both have two work surfaces, the template image obtained on one work surface of the first station is applied to one work surface of the second station, and the template image obtained on the other work surface of the first station is applied to the other work surface of the second station. If any one of the substrates cannot be exposed and the unloading operation is performed, the corresponding relationship between the template images retrieved from the second station and the first station is changed.
[0011] In one embodiment, when both the first station and the second station have two work surfaces, the template image obtained on one work surface of the first station is applied to one work surface of the second station, and the template image obtained on the other work surface of the first station is applied to the other work surface of the second station. If two consecutive substrates cannot be exposed and the unloading operation is performed, the work surface of the work surface in the second station corresponding to the work surface for obtaining the template image remains unchanged.
[0012] In one embodiment, for the dual-stage alignment exposure method, the call sequence is counted based on the time point when the second stage starts to expose.
[0013] In one embodiment, a lower plate working piece is provided at the second station. When the exposure operation of the substrate is not completed, the lower plate operation is to operate the lower plate working piece, and the reading sequence is counted by the number of times the lower plate working piece is operated.
[0014] In one embodiment, the template images simultaneously acquired at the first station are stored using the same index number. For the substrates subjected to exposure operation at the second station, the count of the retrieval sequence is increased by one according to the number of exposure operations or the number of unloading operations. For the substrates not subjected to exposure operation at the second station, the count of the retrieval sequence is increased by one according to the number of unloading operations.
[0015] In one embodiment, the index numbers are named according to the exposure sequence of the substrate.
[0016] In one embodiment, the acquired template images are numbered, and the template images are numbered according to the image acquisition device that acquires the template images.
[0017] Compared with the prior art, the present invention obtains a retrieval sequence by storing the index number of the template image corresponding to the substrate according to the processing order of the substrate at the first workstation, and retrieves the template image corresponding to the current substrate by obtaining the position of the index number corresponding to the current substrate in the retrieval sequence at the second workstation, and aligns and exposes the back of the substrate to avoid alignment failure caused by mismatch between the retrieved template image and the substrate. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a schematic diagram of the double-sided exposure system.
[0019] Figure 2 The first embodiment of the process of batch processing substrate Figure 1 .
[0020] Figure 3 The first embodiment of the process of batch processing substrate Figure 2 .
[0021] Figure 4 The first embodiment of the process of batch processing substrate Figure 3 .
[0022] Figure 5 It is a flowchart of a method for batch processing of substrates.
[0023] Figure 6 2 is a schematic diagram of a second embodiment of batch processing substrates.
[0024] Figure 7 2 is a schematic diagram of a third embodiment of batch processing substrates.
[0025] Figure 8 FIG. 4 is a schematic diagram of a fourth embodiment of batch processing substrates.
[0026] Figure 9 The fifth embodiment of the process for batch processing substrates Figure 1 .
[0027] Figure 10 The fifth embodiment of the process of batch processing substrate Figure 2 .
[0028] Figure 11 This is a system block diagram for double-sided exposure of batch substrates. DETAILED DESCRIPTION
[0029] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is described below with reference to specific embodiments shown in the accompanying drawings.
[0030] Figure 1An exposure system for double-sided exposure of a substrate is shown. The exposure system includes a first station, a second station, and a transport system between the first and second stations. The first station exposes the front side of the substrate, while the second station exposes the back side of the substrate. The transport system transfers the substrate, after the front side exposure at the first station, to the second station.
[0031] The first workstation includes a first workstation table 1 supporting a substrate. The first workstation table is provided with an image acquisition device 10. When the substrate is at the first workstation, the image marking points on the back of the substrate are acquired by the image acquisition device.
[0032] The second workstation includes a second workstation table 2 supporting the substrate, and a positioning device 20 is arranged above the second workstation table. The positioning device adjusts the exposure image based on the actual position of the image marking point obtained by the image acquisition device so that the exposure image on the back is aligned with the exposure image on the front.
[0033] The substrate is transferred from the first workstation to the second workstation via a transport system. At the first workstation, the image acquisition device acquires template information for image markers and stores it in an indexed manner. Specifically, the template information for image markers acquired by the image acquisition device for the same substrate is labeled with an index number, and the template information for image markers includes at least template information for image markers located at two different locations on the substrate. At the second workstation, based on the index number acquired from the first workstation, the template information for the image marker corresponding to the index number is extracted. The position of the image marker is then located on the backside of the substrate based on the template information for the image marker, thereby obtaining alignment information for the backside of the substrate.
[0034] During the flow of the substrate between the first station and the second station, if there is a pause, or the substrate is manually removed and does not continue to move to the second station, confusion is likely to occur when the template information of the image marking point is retrieved at the second station, resulting in the inability to find the image marking point on the back of the substrate using the template information at the second station. In response to the above situation, the present invention provides a processing method for double-sided exposure of batch substrates.
[0035] First workstation: obtain image marking points on the back of the substrate, number the template information of the image marking points obtained at different positions of the substrate, store them under the same index number, and index the template information corresponding to the substrate according to the processing order of the substrate.
[0036] The substrate processed at the first station is moved to the second station through the transport system.
[0037] Second workstation: Get the current index number according to the processing sequence of the substrate, and call the template information corresponding to the current substrate through the current index number.
[0038] After the substrate is transferred to the second workstation via the transport system, if the double-sided exposure system is paused and no substrate is unloaded, upon restart, the template information corresponding to the current substrate is retrieved using the current index number. A count is performed once the substrate is exposed, and no count is performed when the substrate is unloaded while the substrate is being exposed. If the substrate is unloaded without being exposed, a count is performed once. By effectively counting in response to different situations, the second workstation can accurately and timely count both exposed and unexposed substrates, ensuring that the template image and substrate correspond.
[0039] like Figure 2-5 As shown, for an exposure system using a single workbench for double-sided exposure, at the first station, a first substrate A is placed face-up on the first workbench. An image acquisition device located on the first workbench acquires an image of the backside of substrate A, obtaining image markers at different locations on substrate A. Substrate A is the first substrate in a batch of substrates. The template image of the image markers on substrate A is named according to the image acquisition device that acquires the image, stored with the same index number, and placed first in the retrieval sequence. Substrate A is then transferred to the second station via a transport system and placed back-up on the second workbench. An alignment device located above the second workbench acquires an image of the image markers on the backside of substrate A. At this point, the retrieval sequence count is 0. The template image corresponding to substrate A is retrieved by retrieval of the next index number, the first index number in the sequence, and substrate A is aligned with the second station. Exposure is then performed, and the retrieval sequence count is incremented by one, resulting in a sequence count of one. After double-sided exposure of substrate A is completed, the unloading device transfers the substrate to the next station.
[0040] After substrate A completes front-side exposure, it leaves the first workstation. A second substrate, B, is placed face-up on the first work surface for front-side exposure. An image of the back side of substrate B is acquired using an image acquisition device, generating image markers at various locations on substrate B. The template images of the image markers for substrate B are named according to the image acquisition device used to acquire the image and stored using the same index number. The index number corresponding to substrate B is distinct from the index number corresponding to substrate A, and the index numbers of substrates B and A are arranged sequentially, i.e., the index number corresponding to substrate B is located second in the retrieval sequence corresponding to substrate A. The substrate B is transferred to the second station through the transmission system, and the back of the substrate B is placed on the second work table with the back facing up. The image mark point image of the back of the substrate B is obtained on the back of the substrate B through the alignment device located above the second work table. At this time, the count of the sequence is called up as one, and the index number is found by calling the next bit, that is, the second bit of the sequence. The template image corresponding to the substrate B is called up through the index number, and the substrate B at the second station is aligned, and then exposed. The sequence count is called up and added by one. The sequence count value is two. After completing the double-sided exposure of the substrate B, it is transferred to the next station through the lower plate device.
[0041] After substrate B completes front-side exposure and leaves the first workstation, a third substrate, C, is placed face-up on the first work surface. Front-side exposure of substrate C is then performed, and an image acquisition device acquires an image of the back side of substrate C, generating image markers obtained at different locations on substrate C. The template image of the image markers for substrate C is named according to the image acquisition device that acquired the image and stored using the same index number. The index number corresponding to substrate C is distinct from the index numbers for substrates A and B, and is ranked third in the sequence, one position after the index number for substrate B. Substrate C is transferred to the second workstation via the transport system. No alignment or exposure is performed at this station, but the unloading device unloads substrate C, and the count in the retrieved sequence is incremented by one, resulting in a count of three.
[0042] After substrate C completes front-side exposure, it leaves the first workstation. A fourth substrate, D, is placed on the first work surface with its front side facing up. Exposure of the front side of substrate D is then performed, and an image acquisition device acquires an image of the back side of substrate D, obtaining image markers at different locations on substrate D. The template images of the image markers on substrate D are named according to the image acquisition device that acquires the image and stored using the same index number. The index number of substrate D is one position after the index number of substrate C, being the fourth position in the sequence. Substrate D is transferred to the second workstation via a transport system and placed on the second work surface with its back side facing up. An alignment device located above the second work surface acquires images of the image markers on the back side of substrate D. At this point, the sequence count is retrieved to three. The index number next to the sequence count, i.e., the fourth position, is retrieved. The template image corresponding to substrate D is retrieved using this index number. Substrate D at the second workstation is then aligned and exposed. The retrieved sequence count is incremented by one, i.e., the retrieved sequence count is four. After completing double-sided exposure of substrate D, the substrate is transferred to the next workstation via the unloading device.
[0043] Similarly, after the N-1th substrate N-1 completes front-side exposure and leaves the first workstation, the Nth substrate N is placed on the first work surface with its front side facing upwards. Front-side exposure of substrate N is then performed, and an image of the back side of substrate N is acquired by an image acquisition device, resulting in image markers acquired at different locations on substrate N. The template image of the image markers on substrate N is named according to the image acquisition device that acquired the image, and the index number of substrate N is stored using the same index number, one position after the index number of substrate N-1, as the Nth position in the sequence. The substrate N is transferred to the second station through the transmission system, and the back of the substrate N is placed on the second work table with the back facing up. The image mark point image of the back of the substrate N is obtained on the back of the substrate N through the alignment device located above the second work table. At this time, the sequence count is called as N-1, and the index number of the next bit of the sequence count is called, that is, the Nth bit sequence search index number is called, and the template image corresponding to the substrate N is called through the index number. The substrate N at the second station is aligned, and then exposed. The count of the called sequence is added by one, that is, the count of the called sequence is N+1. After completing the double-sided exposure of the substrate N, it is transferred to the next station through the lower plate device.
[0044] At the first workstation, template images acquired at the first workstation are sequentially stored according to the order in which the substrates are loaded, generating a retrieval sequence. Each template image for each substrate is stored in a file with the same index number. Files with the same index number include template images numbered according to the image acquisition device that acquired them.
[0045] At the second station, the number of digits in the index number corresponding to the current substrate in the call sequence is determined based on the count value of the call sequence. Based on the index number, the template image corresponding to the current substrate is obtained, and the back side of the current substrate is then aligned and exposed. The call sequence count is performed as follows: for substrates undergoing exposure at the second station, the number of exposure starts is counted; for substrates not undergoing exposure at the second station, the number of exposure starts is counted.
[0046] like Figure 6-7 As shown, for a method of performing alignment exposure operation on two substrates at the same time, in order to distinguish the two plates being simultaneously exposed, the substrate placed on one side of the work surface is substrate A, and the substrate placed on the other side of the work surface is substrate B. At the first station, template images of the image marking points on the back of substrate A and substrate B are simultaneously obtained. The template images are numbered according to the image acquisition device that obtains the template images. According to the template image number, it is determined whether the template image corresponds to substrate A or substrate B. The template images of substrate A and substrate B are stored in a file named with the same index number. When batch processing substrates, the index numbers are sorted according to the order of alignment exposure to obtain a retrieval sequence. At the second station, based on the previous count of the retrieval sequence, the index number storing the template images of the current substrate A and substrate B is found at the position where the count is increased by one, that is, at the next position in the retrieval sequence that has been counted. The template image is retrieved according to the index number, and alignment exposure is performed on substrate A and substrate B. For substrates A and B that are simultaneously exposed at the second workstation, a count is performed once. If either substrate A or substrate B fails to be exposed, substrates A and B are simultaneously unloaded and a count is performed once. For simultaneous exposure of two substrates, the first and second workstations may each have an exposure mechanism, or the first and second workstations may share the same exposure mechanism, and the work surfaces of the first and second workstations are each moved to the exposure mechanism for exposure.
[0047] like Figure 8-10As shown, a dual-table alignment exposure operation is performed at the same workstation. The two workstations at the first workstation are workstation A and workstation B. The substrate placed on workstation A for alignment exposure is substrate A, and the substrate placed on workstation B for alignment exposure is substrate B. At the second workstation, the two workstations are workstation C and workstation D. When placed in sequence, the substrate placed on workstation C for alignment exposure is substrate A, and the substrate placed on workstation D for alignment exposure is substrate B. Substrate A obtains a template image using the image acquisition device located on workstation A. When substrate A is transferred to the second workstation, substrate A placed on workstation C retrieves the template image obtained on workstation A. Substrate B obtains a template image using the image acquisition device located on workstation B. When substrate B is transferred to the second workstation, substrate B placed on workstation D retrieves the template image obtained on workstation A. The template image of substrate A placed on work surface A is stored in sequence, and the template image of substrate B placed on work surface B is stored in sequence. When the template image is retrieved at the second workstation, the template image corresponding to work surface A is retrieved for work surface C where substrate A is placed, and the template image corresponding to work surface B is retrieved for work surface D where substrate B is placed. If, during the transmission of substrate A and substrate B, any one of substrate A or substrate B cannot complete the alignment exposure operation, substrate A will be placed on work surface D and substrate B will be placed on work surface C. If any substrate cannot complete the alignment exposure operation, the above actions are recorded and the template data corresponding to the work surface is swapped. If, during the transmission of substrate A and substrate B, substrate A and substrate B fail to complete the alignment exposure operation continuously, only the count of the retrieval sequence is increased, and the template images corresponding to work surface C and work surface D obtained through work surface A and work surface B remain unchanged.
[0048] For the above embodiment, the index numbers may be directly named according to the exposure sequence of the substrate.
[0049] In the above embodiment, preferably, the second station is provided with a lower plate operation unit. For lowering the plate on substrates that have not yet been exposed, the lower plate operation unit is operated. Each time the lower plate operation unit is operated, the read sequence is counted. The lower plate operation unit effectively distinguishes between substrates that have not yet been exposed and substrates that have been exposed, thereby avoiding errors in reading sequence counting.
[0050] For dual-stage alignment exposure, it is preferred to count the retrieval sequence based on the start of exposure. Counting the retrieval sequence in a timely manner can effectively avoid retrieval data errors caused by the other stage starting to retrieve the sequence for alignment while the current stage has not yet counted the retrieval sequence.
[0051] For the single-stage embodiment described above, for exposed substrates, the call sequence can be counted based on the time point of exposure completion or board removal. For unexposed substrates, the call sequence can be counted by operating the board removal workpiece.
[0052] like Figure 11 As shown, the system corresponding to the above-mentioned method for double-sided exposure of batch substrates includes an image acquisition control system, a template image storage system, an image retrieval control system, a counting system, an image exposure system, and a lower plate system. The image acquisition control system controls the image acquisition device to acquire images of the back side of the substrate and transmit them to the template image storage system for storage. The template images acquired simultaneously by the image acquisition device are stored using the same index number and a retrieval sequence is obtained based on the acquisition order, or the index number is named based on the acquisition sequence number. The counting system counts based on the image exposure system and the lower plate system. Substrates undergoing back-side image exposure are counted by the image exposure system, while substrates not undergoing image exposure are counted by the lower plate system. The image retrieval control system retrieves the template image at the next position in the retrieval sequence based on the counts of the counting system. The lower plate system includes a lower plate working unit, and by operating the lower plate working unit, counts the read sequence. The image exposure system is used to expose the back side of the substrate, and the lower plate system is used for substrates whose back side has not been exposed. Both the image exposure system and the lower plate system are used in workstations that operate on the back side of the substrate.
Claims
1. An exposure system for double-sided exposure of a batch of substrates, characterized in that: The exposure system includes a first workstation, a second workstation and a transmission system between the first and second workstations. The first workstation exposes the front side of the substrate, obtains image marking points on the back side of the substrate as a template image, stores the template image corresponding to the substrate by index number according to the processing sequence of the substrate, and obtains a retrieval sequence. The transmission system transfers the substrate that has completed front exposure at the first workstation to the second workstation. At the second workstation, the position of the index number corresponding to the current substrate in the retrieval sequence is obtained according to the processing sequence of the substrate. The template image corresponding to the current substrate is retrieved by the obtained index number, and the back side of the substrate is aligned and exposed.
2. The exposure system for double-sided exposure of batch substrates according to claim 1, characterized in that: The position of the index number corresponding to the current substrate in the call sequence is obtained according to the processing order of the substrate, and is obtained by counting the call sequence during batch processing.
3. The exposure system for double-sided exposure of batch substrates according to claim 2, characterized in that: For substrates that are exposed at the second station, the number of exposure operations or unloading operations is used to count the call sequence. For substrates that are not exposed at the second station, the number of unloading operations is used to count the call sequence.
4. The exposure system for double-sided exposure of a batch of substrates according to claim 2, characterized in that : At the first station and the second station, when two substrates are simultaneously subjected to the alignment exposure operation, neither substrate can be subjected to the exposure operation, and the two substrates are simultaneously subjected to the unloading operation and the sequence counting is performed.
5. The exposure system for double-sided exposure of batch substrates according to claim 2, wherein: When both the first station and the second station have two work surfaces, the template image obtained on one work surface of the first station is applied to one work surface of the second station, and the template image obtained on the other work surface of the first station is applied to the other work surface of the second station. If any of the substrates cannot be exposed and the unloading operation is performed, the corresponding relationship between the template images retrieved from the second station and the first station is changed.
6. The exposure system for double-sided exposure of batch substrates according to claim 2, wherein: When both the first station and the second station have two work surfaces, the template image obtained on one work surface of the first station is applied to one work surface of the second station, and the template image obtained on the other work surface of the first station is applied to the other work surface of the second station. If two consecutive substrates cannot be exposed and the unloading operation is performed, the work surface in the second station corresponding to the work surface where the template image is obtained remains unchanged.
7. The exposure system for double-sided exposure of batch substrates according to claim 2, wherein: For the dual-stage alignment exposure method, the call sequence is counted from the time point when the second station starts to expose.
8. The exposure system for double-sided exposure of batch substrates according to claim 2, wherein: A lower plate working piece is set at the second station. When the exposure operation of the substrate is not completed, the lower plate operation is to operate the lower plate working piece, and the reading sequence is counted according to the number of times the lower plate working piece is operated.
9. The exposure system for double-sided exposure of batch substrates according to claim 1, wherein: The template images obtained simultaneously at the first workstation are stored using the same index number. For the substrate undergoing exposure operation at the second workstation, the count of the retrieval sequence is increased by one according to the number of exposure operations or the number of plate removal operations. For the substrate not undergoing exposure operation at the second workstation, the count of the retrieval sequence is increased by one according to the number of plate removal operations.
10. The exposure system for double-sided exposure of batch substrates according to claim 1, wherein: The index numbers are named after the order in which the substrates were exposed.
11. The exposure system for double-sided exposure of batch substrates according to claim 1, wherein: The acquired template images are numbered, wherein the template images are numbered according to an image acquisition device that acquires the template images.