A method and system for double-sided exposure of a batch of substrates

Abstract

A method and system for double-side exposure of batch substrates, the front side of the substrate is exposed at a first station, and a template image is obtained from the back side of the substrate, the back side of the substrate is exposed at a second station, and the substrate is aligned by the template image, the index number storage is performed according to the sequence of the template image obtained at the first station, the call sequence is obtained, the template image is called one by one according to the sequence of the call sequence at the second station, in the batch processing process, the number of exposure operations is counted for the substrate which is subjected to the exposure operation at the second station, and the number of plate operations is counted for the substrate which is not subjected to the exposure operation at the second station. The call sequence is counted in time and accurately, and the alignment failure caused by the mismatch between the called template image and the substrate is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser processing, and in particular to a method and system for double-side exposure of the front and back surfaces of a substrate. BACKGROUND

[0002] Exposure technology is widely used in the fields of semiconductor and PCB production, and is one of the process steps for manufacturing semiconductor devices, chips and PCB boards and the like. It is used to print feature patterns on the surface of a substrate to ultimately obtain the required pattern structure according to the circuit design. Traditional exposure technology requires the production of a mask master or a film negative to perform exposure operations, and has a long production cycle. Moreover, each version corresponds to a single pattern and cannot be widely applied. To solve the above problems existing in traditional exposure technology, direct writing exposure technology has emerged. It uses digital light processing technology to achieve editing of different pattern structures through a programmable digital mirror device, which can quickly switch patterns. It not only can reduce costs, but also can shorten the production cycle, and is widely used in the field of exposure technology. The principle of direct writing exposure is to transfer the designed pattern to the surface of a substrate coated with a photosensitive material by modulating the light beam, and then to ultimately obtain the required pattern structure through development, etching and other processes.

[0003] For printed circuit boards, a multi-layer board is usually used, and an inner layer board that can be double-sidedly connected is required in the multi-layer board. The inner layer board not only needs to be single-side exposed, but also needs to be exposed on both sides. When the inner layer board is exposed, its front and back surfaces need to be exposed respectively, and the positions of the patterns on the front and back surfaces of the inner layer board need to be ensured to correspond to each other. In the prior art, when the first surface pattern is exposed on the front surface of the inner layer board, a marking device is used to form a positioning mark on the back surface of the inner layer board. After the exposure of the front surface of the inner layer board is completed, the back surface of the inner layer board is placed upward, and a positioning camera is used to capture the positioning mark to calculate the accurate printing position of the pattern to be drawn on the second surface. The marking device needs to use a laser to form a mark on the back surface of the inner layer board. However, the energy of the laser is not easy to control, the shape of the boundary of the mark is easy to change, and it is difficult to accurately identify the boundary, resulting in reduced accuracy. In order to solve the above problems, a processing method is provided in the prior art, in which an image acquisition device is arranged on the back surface of the substrate, a feature image of the back surface of the substrate is acquired by the image acquisition device, a template image is obtained from the feature image, and the template image is matched on the back surface of the substrate for positioning when the back surface of the substrate is exposed. However, when batch processing is performed, the template images acquired for each substrate are different, and the corresponding template image needs to be acquired for positioning. Since a large number of template images need to be stored, confusion often occurs during batch processing, resulting in the inability to position. SUMMARY

[0004] The technical problem solved by the present application is to provide a method and system for processing batch substrates for double-sided exposure, solving the problem of misalignment due to mismatched template images.

[0005] To solve the above problems, the present application provides a method for double-sided exposure of batch substrates, exposing the front side of the substrate at a first station, obtaining a template image on the back side of the substrate, exposing the back side of the substrate at a second station, and aligning the substrate by the template image, storing the index number in the order of the template image obtained at the first station to obtain a retrieval sequence, retrieving the template image in the order of the retrieval sequence at the second station, and counting the number of exposure operations for the substrate exposed at the second station during batch processing, and counting the number of plate operations for the substrate not exposed at the second station.

[0006] When two substrates are simultaneously aligned and exposed at the first and second stations, any substrate cannot be exposed, two substrates are simultaneously moved, and the count of the retrieval sequence is performed.

[0007] When the first and second stations each have two worktables, the template image obtained at one worktable of the first station is applied to one worktable of the second station, and the template image obtained at the other worktable of the first station is applied to the other worktable of the second station, and if any of the substrates cannot be exposed and is moved, the corresponding relationship of the template image retrieved at the second station and the first station is changed.

[0008] When the first and second stations each have two worktables, the template image obtained at one worktable of the first station is applied to one worktable of the second station, and the template image obtained at the other worktable of the first station is applied to the other worktable of the second station, and if two consecutive substrates cannot be exposed and are moved, the worktable corresponding to the template image obtained at the worktable of the second station remains unchanged.

[0009] The number of exposure operations is counted from the start of exposure as the time point.

[0010] The worktables of the first and second stations share the same exposure mechanism and are moved to the exposure mechanism from both sides of the exposure mechanism, respectively.

[0011] The second station is provided with a plate moving member, and when the substrate has not completed the exposure operation, the plate moving member is operated to count the retrieval sequence.

[0012] The template images obtained simultaneously at the first station are stored by the same index number.

[0013] The index number is named according to the exposure sequence of the substrate.

[0014] The obtained template images are numbered, and the numbering of the template images is numbered according to the image acquisition device that acquires the template images.

[0015] A system for double-sided exposure of batch substrates, comprising an image acquisition control system, a template image storage system, a call image control system, a counting system, an image exposure system and a plate lowering system, the image acquisition control system controls the image acquisition device to acquire the image of the back of the substrate and transmits it to the template image storage system for storage, the image acquisition device simultaneously stores the obtained template images through the same index number, and obtains a call sequence according to the acquisition sequence, or the index number is named according to the acquisition sequence number, the counting system counts according to the image exposure system and the plate lowering system, the substrate that has completed image exposure is counted by the image exposure system, and the substrate that has not been subjected to image exposure is counted by the plate lowering system, the call image control system calls the template image located at the next position in the call sequence according to the counting of the call template image counting system.

[0016] Compared with the prior art, the call sequence is counted in time and accurately for different situations of the substrate, and the mismatch between the called template image and the substrate is avoided to cause alignment failure. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a schematic diagram of a double-sided exposure system.

[0018] Figure 2 is a process of batch processing substrates in the first embodiment Figure One .

[0019] Figure 3 is a process of batch processing substrates in the first embodiment Figure Two .

[0020] Figure 4 is a process of batch processing substrates in the first embodiment Figure Three .

[0021] Figure 5 is a flow chart of a method for batch processing substrates.

[0022] Figure 6 is a schematic diagram of a second embodiment of batch processing substrates.

[0023] Figure 7 is a schematic diagram of a third embodiment of batch processing substrates.

[0024] Figure 8 is a schematic diagram of a fourth embodiment of batch processing substrates.

[0025] Figure 9is a batch processing substrate fifth embodiment process Figure One .

[0026] Figure 10 is a batch processing substrate fifth embodiment process Figure Two .

[0027] Figure 11 is a system block diagram for batch substrate double-side exposure. DETAILED DESCRIPTION

[0028] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be described below by specific embodiments shown in the drawings.

[0029] Figure 1 An exposure system for double-side exposure of a substrate is shown, the exposure system comprising a first station, a second station, a transport system between the first station and the second station. The first station exposes the front side of the substrate, the second station exposes the back side of the substrate, and the transport system transfers the substrate after front side exposure in the first station to the second station.

[0030] The first station comprises a first station table 1 supporting the substrate, the first station table is provided with an image acquisition device 10, and the image acquisition device acquires image mark points on the back side of the substrate when the substrate is in the first station.

[0031] The second station comprises a second station table 2 supporting the substrate, and an alignment device 20 is arranged above the second station table, the alignment device adjusts the exposure image based on the actual position of the image mark points obtained by the image acquisition device, so that the exposure image on the back side is aligned with the exposure image on the front side.

[0032] The substrate is transferred from the first station to the second station by the transport system, the image acquisition device acquires template information of the image mark points in the first station and stores it by indexing, that is, the template information of the image mark points acquired by the image acquisition device corresponding to the same substrate is marked by an index number, and the template information of the image mark points at least includes template information of image mark points at two different position points of the substrate. In the second station, according to the index number acquired from the first station, the template information of the image mark points corresponding to the index number is extracted, the position of the image mark points on the back side of the substrate is searched according to the template information of the image mark points, and the alignment information of the back side of the substrate is obtained.

[0033] If the substrate pauses or is manually removed from the first station without continuing to move to the second station during the process of transferring the substrate between the first station and the second station, confusion occurs when the template information of the image mark point is retrieved at the second station, resulting in that the image mark point cannot be found on the back of the substrate at the second station using the template information. To address the above situation, the application provides a processing method for double-sided exposure of batch substrates.

[0034] The first station: image mark points are obtained on the back of the substrate, template information of the image mark points obtained at different positions of the substrate is numbered and stored under the same index number, and the template information corresponding to the substrate is indexed and numbered according to the processing sequence of the substrate.

[0035] The substrate processed at the first station is moved to the second station by the conveying system.

[0036] The second station: the current index number is obtained according to the processing sequence of the substrate, and the template information corresponding to the current substrate is retrieved through the current index number.

[0037] After the substrate is transferred to the second station by the conveying system, if the exposure system for double-sided exposure is paused and the substrate is not subjected to the plate removal operation, the corresponding template information of the current substrate is still retrieved through the current index number when the exposure system is restarted. The substrate is subjected to exposure, and the counting is performed once. The counting is not performed when the substrate is subjected to the plate removal operation. The counting is performed once when the substrate is not subjected to exposure but is directly subjected to the plate removal operation. Through effective counting corresponding to different situations, the substrate subjected to exposure and the substrate not subjected to exposure are accurately counted in a timely manner at the second station, so that the template image corresponds to the substrate.

[0038] As shown in Figures 2-5 For the exposure system for double-sided exposure using a single table, at the first station, a first substrate A is placed face up on a first worktable, an image acquisition device placed on the first worktable obtains an image on the back of the substrate A, and an image mark point obtained at different positions of the substrate A is obtained. The substrate A is the first substrate in the batch of substrates. The template image of the image mark point of the substrate A is named according to the image acquisition device that obtains the image, is stored under the same index number, and is located at the first position of the retrieval sequence. The substrate A is transferred to the second station by the conveying system, the back of the substrate A is placed face up on a second worktable, an alignment device located above the second worktable obtains an image mark point image on the back of the substrate A on the back of the substrate A, at this time, the count of the retrieval sequence is 0, the index number of the first position of the sequence is retrieved to retrieve the template image corresponding to the substrate A by retrieving the next position, the substrate A at the second station is aligned, and then is subjected to exposure, the count of the retrieval sequence is incremented by 1, the count value of the sequence is 1, after the double-sided exposure of the substrate A is completed, the substrate A is transferred to the next station by a plate removal device.

[0039] Substrate A completes its front exposure and leaves the first workstation. A second substrate B, face up, is placed on the first worktable for front exposure. An image of the back side of substrate B is obtained using an image acquisition device, resulting in image markers at different locations on substrate B. Template images of these image markers are named according to the image acquisition device used to acquire the images and stored using the same index number. The index number corresponding to substrate B is distinct from the index number corresponding to substrate A. The index numbers of substrate B and substrate A are arranged sequentially; that is, the index number corresponding to substrate B is the second position in the retrieval sequence corresponding to substrate A. Substrate B is transferred to the second station via a transmission system. Substrate B is placed with its back side facing up on the second worktable. An alignment device located above the second worktable acquires an image of the image marker points on the back side of substrate B. At this point, the sequence count is one. The next bit is retrieved, i.e., the second bit of the sequence, to find the index number. The template image corresponding to substrate B is retrieved using the index number. Substrate B is aligned at the second station, and then exposure is performed. The sequence count is incremented by one, and the sequence count value is two. After the double-sided exposure of substrate B is completed, it is transferred to the next station via a plate-down device.

[0040] Substrate B completes its front exposure and leaves the first station. The third substrate C is placed face up on the first worktable for front exposure, and an image of the back of substrate C is obtained through an image acquisition device, resulting in image markers at different locations on substrate C. The template images of these image markers are named according to the image acquisition device used to acquire the images and stored using the same index number. The index number corresponding to substrate C is distinct from the index numbers of substrates A and B. The index number of substrate C is one position after that of substrate B, and is the third position in the sequence. Substrate C is transferred to the second station via a transmission system. At the second station, no alignment or exposure is performed; instead, the substrate C is removed from the plate by the unmounting device, incrementing the sequence count by one, i.e., the sequence count becomes three.

[0041] The substrate C is transferred to the second station by the conveying system, and the back of the substrate C is placed upward on the second worktable. The image acquisition device located above the second worktable acquires the image of the image mark points on the back of the substrate C. At this time, the sequence count is 3, and the index number in the next position of the sequence count, i.e., the fourth position of the sequence, is called. The template image corresponding to the substrate C is called through the index number, and the substrate C in the second station is aligned, and then exposed. The sequence count is increased by one, i.e., the sequence count is 4. After the double-side exposure of the substrate C is completed, the substrate C is transferred to the next station by the plate lowering device.

[0042] By analogy, the N-1th substrate N-1 completes the front-side exposure and leaves the first station, and the Nth substrate N is placed upward on the first worktable for front-side exposure. The image acquisition device acquires the image of the back of the substrate N, and the image mark points obtained at different positions of the substrate N are obtained. The template image of the image mark points of the substrate N is named according to the image acquisition device that acquires the image, and the index number of the substrate N is stored in the same index number. The index number of the substrate N is arranged in the next position of the index number of the substrate N-1, and is the Nth position of the sequence. The substrate N is transferred to the second station by the conveying system, and the back of the substrate N is placed upward on the second worktable. The image acquisition device located above the second worktable acquires the image of the image mark points on the back of the substrate N. At this time, the sequence count is N-1, and the index number in the next position of the sequence count, i.e., the Nth position of the sequence, is called. The template image corresponding to the substrate N is called through the index number, and the substrate N in the second station is aligned, and then exposed. The sequence count is increased by one, i.e., the sequence count is N+1. After the double-side exposure of the substrate N is completed, the substrate N is transferred to the next station by the plate lowering device.

[0043] In the first station, the template images of the substrates acquired in the first station are sequentially stored according to the feeding sequence of the substrates, and a sequence is obtained. The template image of each substrate is stored in a file named by the same index number, and the template image is numbered according to the image acquisition device that acquires the template image in the file with the same index number.

[0044] In the second station, according to the count value of the calling sequence, the bit number of the index number corresponding to the current substrate in the calling sequence is determined, and the template image corresponding to the current substrate is obtained according to the index number, and then the back of the current substrate is aligned and exposed. The counting method of the calling sequence is as follows: for the substrate that is exposed in the second station, the number of times of starting exposure is counted; for the substrate that is not exposed in the second station, the number of times is counted.

[0045] As shown in Figures 6-7 For the way of simultaneously aligning and exposing two substrates, in order to distinguish the two plates that are simultaneously aligned and exposed, the substrate placed on one side of the workbench is substrate A, and the substrate placed on the other side of the workbench is substrate B. In the first station, the template images of the back image markers of substrate A and substrate B are obtained simultaneously, the template images are numbered according to the image acquisition device that obtains the template images, and it is determined according to the numbering of the template images whether the template images correspond to substrate A or substrate B. The template images of the substrate A and the substrate B are stored in the same index number named file. When processing the substrates in batches, the index numbers are sorted according to the order of alignment and exposure to obtain a calling sequence. In the second station, according to the counting of the calling sequence in advance, the index number storing the template images of the current substrate A and substrate B is found in the next bit of the counting plus one, that is, the next bit of the calling sequence that has been counted. The template images are called according to the index number, and the substrate A and the substrate B are aligned and exposed. For the substrate A and the substrate B that are simultaneously exposed in the second station, the counting is once. If any of the substrate A or the substrate B fails to perform the exposure operation, the substrate A and the substrate B are simultaneously subjected to the next plate operation, and the counting is once. For the case of simultaneously exposing two substrates, the first station and the second station can have exposure mechanisms respectively, or the first station and the second station can share the same exposure mechanism. The workbench of the first station and the workbench of the second station are moved to the exposure mechanism to perform the exposure operation respectively.

[0046] As shown in Figures 8-10As shown, the double table surfaces are used for alignment exposure operation in the same station. In the first station, the two worktable surfaces are worktable surface A and worktable surface B. The substrate placed on worktable surface A for alignment exposure operation is substrate A, and the substrate placed on worktable surface B for alignment exposure operation is substrate B. In the second station, the two worktable surfaces are worktable surface C and worktable surface D. When placed in sequence, the substrate placed on worktable surface C for alignment exposure operation is substrate A, and the substrate placed on worktable surface D for alignment exposure operation is substrate B. Substrate A obtains the template image through the image acquisition device arranged on worktable surface A. When substrate A is transferred to the second station, the substrate placed on worktable surface C retrieves the template image obtained on worktable surface A. Substrate B obtains the template image through the image acquisition device arranged on worktable surface B. When substrate B is transferred to the second station, the substrate placed on worktable surface D retrieves the template image obtained on worktable surface A. The template image of substrate A placed on worktable surface A is stored in sequence, and the template image of substrate B placed on worktable surface B is stored in sequence. When the template image is retrieved in the second station, the template image corresponding to worktable surface A is retrieved for worktable surface C where substrate A is placed, and the template image corresponding to worktable surface B is retrieved for worktable surface D where substrate B is placed. If either substrate A or substrate B cannot complete the alignment exposure operation during the transmission process, substrate A will be placed on worktable D, and substrate B will be placed on worktable C. If the substrate cannot complete the alignment exposure operation, the above-mentioned actions are recorded, and the template data corresponding to the worktable is exchanged. If the substrate A and substrate B cannot complete the alignment exposure operation continuously during the transmission process, only the count of the retrieval sequence is increased, and the template images obtained through worktable A and worktable B corresponding to worktable C and worktable D do not change.

[0047] For the above-mentioned embodiments, the index number can be directly named according to the exposure sequence of the substrate.

[0048] For the above-mentioned embodiments, preferably, the second station is provided with a lower plate operation member. For the lower plate operation of the substrate that has not been exposed, the lower plate operation member is used. Each time the lower plate operation member is operated, the reading sequence is counted once. The lower plate operation member effectively distinguishes the substrate that has not been exposed from the substrate that has been exposed, thereby avoiding errors in counting the reading sequence.

[0049] For the double-table alignment exposure method, preferably, the count of the retrieval sequence is started at the time point of starting exposure. The count of the retrieval sequence is timely, which can effectively avoid errors in retrieval data caused by the fact that the other table has started the count of the retrieval sequence for alignment, while the current table has not started the count of the retrieval sequence.

[0050] For the above single facet embodiment, for the substrate being exposed, the call sequence can be counted at the time point of exposure completion or plate down. For the substrate not being exposed, the call sequence can be counted by operating the plate down workpiece.

[0051] As shown in Figure 11 The system corresponding to the above method of double-sided exposure of batch substrates includes an image acquisition control system, a template image storage system, a call image control system, a counting system, an image exposure system, and a plate down system. The image acquisition control system controls the image acquisition device to acquire the image of the back of the substrate and transmit it to the template image storage system for storage. The template images acquired by the image acquisition device at the same time are stored by the same index number and obtain the call sequence according to the acquisition order, or the index number is named by the acquisition order number. The counting system counts according to the image exposure system and the plate down system. The substrate being exposed on the back of the image is counted by the image exposure system. The substrate not being exposed on the back of the image is counted by the plate down system. The call image control system calls the template image located at the next position of the call sequence according to the counting of the counting system. The plate down system includes a plate down workpiece. The call sequence is counted by operating the plate down workpiece. The image exposure system is used for exposure operation on the back of the substrate. The plate down system is used for the substrate not being exposed on the back of the substrate. The image exposure system and the plate down system are both applied to the station for operation on the back of the substrate.

Claims

1. A method of double side exposure of a batch of substrates, characterized by: The front surface of the substrate is exposed in the first station, and the template image of the image mark point on the back surface of the substrate is obtained, the index number is stored in the order of the template image obtained in the first station, and the calling sequence is obtained. In the second station, the template image corresponding to the current substrate is called according to the position of the template image in the calling sequence when the back surface of the substrate is exposed in the second station, and the substrate is aligned through the template image. In the batch processing process, for the substrate that is exposed in the second station, the number of exposure operations is counted in the calling sequence, and for the substrate that is not exposed in the second station, the next plate operation is counted in the calling sequence, and the position of the template image corresponding to the current substrate in the calling sequence is obtained.

2. The method of claim 1, wherein In the first station and the second station, when two substrates are simultaneously aligned and exposed, any substrate cannot be exposed, and the two substrates are simultaneously operated and the counting sequence is counted.

3. The method of claim 1, wherein: When the first station and the second station each have two worktable surfaces, the template image obtained on one worktable surface of the first station is applied to one worktable surface of the second station, and the template image obtained on the other worktable surface of the first station is applied to the other worktable surface of the second station. If any of the substrates cannot be exposed and is operated, the corresponding relationship between the second station and the first station for calling the template image is changed.

4. The method of claim 1, wherein: When the first station and the second station each have two worktable surfaces, the template image obtained on one worktable surface of the first station is applied to one worktable surface of the second station, and the template image obtained on the other worktable surface of the first station is applied to the other worktable surface of the second station. If any of the substrates cannot be exposed and is operated, the corresponding relationship between the second station and the first station for calling the template image is changed.

5. The method of claim 1, 3 or 4, wherein: The counting is counted from the time point of exposure start.

6. The method of claim 1, wherein: The worktable surfaces of the first station and the second station share the same exposure mechanism, and are respectively moved to the exposure mechanism from both sides of the exposure mechanism.

7. The method of claim 1, wherein: A next plate operation member is arranged in the second station, and when the substrate is not completed exposure operation, the next plate operation is operated by the next plate operation member, and the reading sequence is counted by the number of operations of the next plate operation member.

8. The method of claim 1, wherein: The template images obtained in the first station are stored by the same index number.

9. The method of claim 1, wherein: The index number is named according to the exposure sequence of the substrate.

10. The method of claim 1, wherein: The obtained template image is numbered, and the number of the template image is numbered according to the image acquisition device of the obtained template image. The template images obtained in the first station are stored by the same index number. The index number is named according to the exposure sequence of the substrate. The obtained template image is numbered, and the number of the template image is numbered according to the image acquisition device of the obtained template image.

11. A system for double-sided exposure of batch substrates, comprising an image acquisition control system, a template image storage system, a retrieval image control system, a counting system, an image exposure system and a plate lowering system, the image acquisition control system controls an image acquisition device to acquire template images of image mark points on the back of a substrate and transmit to the template image storage system for storage, the template image storage system stores template images acquired by the image acquisition device at the same time through the same index number, and obtains a retrieval sequence according to the feeding sequence of the substrate, or the index number is named according to the exposure sequence of the substrate, the counting system counts according to the image exposure system and the plate lowering system, the substrate on which image exposure is completed is counted by the image exposure system, and the substrate on which image exposure is not performed is counted by the plate lowering system, the retrieval image control system retrieves the template image located at the next position according to the counting of the counting system.

Images