TW202000350A - Processing method and processing device capable of reducing the deviation between the location of a predetermined point to-be-processed and an actual processed location - Google Patents

Abstract

The present invention provides a processing method capable of reducing the deviation between the location of a predetermined point to-be-processed and an actual processed location. A surface to-be-processed of a substrate is divided into a plurality of unit areas, and an alignment mark is provided correspondingly to each of the unit areas. Locations of a plurality of points to-be-processed are defined in the interior of the unit area. When the aforementioned points to-be-processed in the interior of each of the unit areas are being processed, each of the processing of the unit area detects the location of the alignment mark corresponding to the unit area to be processed subsequently, and the processing of each of the points to-be-processed is performed according to the detection result.

Description

Processing method and processing device

This application claims priority based on Japanese Patent Application No. 2018-111015 filed on June 11, 2018. The entire contents of this Japanese application are incorporated into this specification by reference. The invention relates to a processing method and a processing device.

Conventionally, when drilling a substrate using a laser beam, the position of an alignment mark formed at a predetermined position is measured for each substrate before processing (Patent Document 1). The position of the substrate is detected based on the measurement result of the position of the alignment mark, and the laser beam is incident on a predetermined processing point. With this, laser processing, such as drilling processing, of the processing point at a predetermined position can be performed based on the alignment mark. [Prior Technical Literature] [Patent Literature]

Patent Literature 1: International Publication No. 2013/114593

[Problems to be solved by the invention]

According to the evaluation experiment of the inventor of the present application, it is known that even if the position of the alignment mark is accurately detected (measured), the laser beam is incident on the processing point according to the detection result, and is actually processed by the incident of the laser beam The point may still deviate from the target processed point. An object of the present invention is to provide a processing method and a processing apparatus capable of reducing the deviation between the position of a predetermined processing point and the actual processing position. [Technical means to solve the problem]

According to an aspect of the present invention, a processing method is provided, which includes the following process: processing a processed point in each of a plurality of unit areas of a substrate, the processed surface of the substrate is divided into a plurality of the unit areas, corresponding to An alignment mark is provided in each of the unit areas, and a plurality of positions of the processed points are defined inside the unit area, Each of the processing of the unit area detects the position of the alignment mark corresponding to the unit area to be processed next, and performs processing of the processed point according to the detection result.

According to other aspects of the present invention, a processing device is provided, which has: Laser light source, output laser beam; A beam scanner, incident the laser beam output from the laser light source on the surface of the substrate, and moving the incident position on the surface of the substrate; Sensors to detect alignment marks provided on the aforementioned substrate; and In the control device, the processed surface is divided into a plurality of unit areas, and the positions of the plurality of processed points of the processed surface are stored. Each of the processing of the unit area is detected based on the detection result of the sensor The position of the alignment mark corresponding to the unit area to be processed next controls the beam scanner according to the detection result so that the laser beams are incident on the processed point in sequence.

According to another aspect of the present invention, a processing method is provided which alternately repeats the following processes multiple times: Detecting the position of the alignment mark of at least a part of the substrate, a plurality of the alignment marks are provided on the substrate and the positions of the plurality of processed points to be processed are defined, According to the detection result of the position of the aforementioned alignment mark, a part of the plurality of processed points is processed in sequence.

According to another aspect of the present invention, a processing device is provided, which has: Laser light source, output laser beam; A beam scanner, incident the laser beam output from the aforementioned laser light source on the processed surface of the substrate, and moving the incident position on the surface of the aforementioned substrate; A sensor to detect each of the plurality of alignment marks provided on the aforementioned substrate; and The control device stores the positions of the plurality of processed points on the processed surface, and controls the laser light source and the beam scanner according to the detection result of the sensor, The aforementioned control device repeats the following processing alternately a plurality of times: Detecting at least a part of the position of the alignment mark based on the detection result of the sensor, The laser light source and the beam scanner are controlled based on the detection result of the position of the alignment mark, and a part of the plurality of processed points is processed in sequence. [Effect of invention]

It can reduce the deviation between the position of the scheduled processing point and the actual processing position.

1 to 3, the processing method and the processing apparatus based on the embodiment will be described. FIG. 1 is a schematic diagram of a laser processing apparatus based on an embodiment. The laser light source 10 outputs a pulsed laser beam. As the laser light source 10, for example, a carbon dioxide laser oscillator can be used. The pulsed laser beam output from the laser light source 10 enters the substrate 30 to be processed held on the stage 17 via the acousto-optical element (AOM) 11, the reflecting mirror 12, the beam scanner 13, and the condenser lens 14.

The AOM 11 intercepts the laser pulse of the pulse laser beam output from the laser light source 10 for processing a part according to an instruction from the control device 20. The intercepted laser pulses are directed to the substrate 30 as the object to be processed, and the remaining pulsed laser beams are incident on the beam damper 15.

The beam scanner 13 receives an instruction from the control device 20 and moves the incident position of the pulsed laser beam on the surface of the substrate 30 by scanning the laser beam in a two-dimensional direction. As the beam scanner 13, for example, a galvanometer scanner having a pair of galvanometer mirrors can be used.

The condenser lens 14 condenses the pulsed laser beam scanned by the beam scanner 13 onto the surface (processed surface) of the substrate 30. As the condenser lens 14, for example, an fθ lens can be used.

A sensor 16 is arranged above the stage 17. The sensor 16 detects the alignment mark provided on the substrate 30 held on the stage 17. For example, as the sensor 16, an imaging device is used. The imaging device images the processed surface of the substrate 30 to generate image data. The image data generated by the camera device is loaded into the control device 20.

The stage 17 receives an instruction from the control device 20 and moves the substrate 30 in a two-dimensional direction parallel to the processed surface. As the stage 17, for example, an XY stage can be used. The substrate 30 is moved, and the alignment marks provided on the substrate 30 are arranged within the detectable range of the sensor 16, so that the sensor 16 can detect the alignment marks.

The control device 20 includes a storage device 21. The storage device 21 stores the positions of a plurality of processing points defined on the processing surface of the substrate 30. The control device 20 has a function of detecting the position of the alignment mark provided on the substrate 30 based on the detection result of the sensor 16. For example, the control device 20 detects the position of the alignment mark by performing image analysis on the image data acquired from the sensor 16. Furthermore, the control device controls the beam scanner 13 based on the detection result of the position of the alignment mark so that the laser beam enters the processing point.

In some cases, a lens system, an aperture, etc. may be arranged in the optical path of the pulsed laser beam from the laser light source 10 to the substrate 30 as needed.

FIG. 2 is a plan view of the substrate 30 to be processed. The processed surface of the substrate 30 is divided into a plurality of unit regions 32. Here, “differentiation” means that the unit area 32 is handled as a whole during processing, and does not mean that the unit area 32 can be recognized in appearance. In FIG. 2, as an example, six unit regions 32 are arranged in a matrix of 2 rows and 3 columns, and an example in which each unit region 32 has a rectangular shape is shown. As another example, the number of unit areas 32 may not be six. The arrangement of the plurality of unit areas 32 may not be in a matrix. Moreover, the shape of each unit area 32 may not be a rectangle.

A plurality of alignment marks 31 are provided inside the unit area 32 corresponding to each unit area 32. As an example, FIG. 2 shows an example in which alignment marks 31 are arranged slightly inside the four corners of each unit area 32. The alignment mark 31 is preferably arranged so as to define the position of the unit area 32 based on the stage 17 and the posture of the rotation direction centered on the axis perpendicular to the surface to be processed. Furthermore, it is desirable to arrange so that the strain of the unit area 32 can be measured.

Within each unit area 32, a plurality of positions of the processed points 33 are defined in advance. The information defining the positions of the plurality of processed points 33 is stored in the storage device 21 of the control device 20. Before processing, the processed point 33 cannot be visually recognized.

FIG. 3 is a flowchart of the processing method based on this embodiment. First, the control device 20 detects the position of the alignment mark 31 corresponding to one unit area 32 (FIG. 2) to be processed next (step SA1). Hereinafter, the procedure for detecting the position of the alignment mark 31 will be described. The control device 20 controls the stage 17 so that an alignment mark 31 corresponding to the unit area 32 to be processed next moves within the detectable range of the sensor 16 (FIG. 1 ). The control device 20 analyzes the image data obtained by the sensor 16 to detect the position of the alignment mark 31. Similarly, the positions of the remaining plural alignment marks 31 are detected.

The control device 20 controls the laser light source 10, the AOM 11, and the beam scanner 13 based on the detection result of the position of the alignment mark 31. With this, the laser beam is sequentially incident on the plurality of processed points 33 in the unit area 32 corresponding to the detected position alignment mark 31, and all the processed points 33 in the unit area 32 are processed (step SA2 ).

The control device 20 repeatedly executes steps SA1 and SA2 until the processing of all the processed points 33 in all unit areas 32 is completed (step SA3).

Next, the excellent effects of this embodiment will be described. According to the evaluation experiment conducted by the inventors of the present application, it is found that if a through hole is formed at the processed point 33 of the substrate 30 (FIG. 2) by the incidence of the laser beam, strain may occur on the substrate 30. In particular, it is understood that when the thickness of the substrate 30 is 0.04 mm or less, the substrate 30 is easily deformed. Conventionally, the position of the alignment mark 31 is detected before the substrate 30 is processed, and all unit regions 32 are processed based on the detection result. If the substrate 30 is strained as the processing progresses, among the processed points 33 to be processed after the strain occurs, the position of the original processed point 33 to be processed and the position where the laser beam is incident may deviate. This phenomenon was not known at the time of filing this application.

In the present embodiment, each processing of the unit area 32 is to detect the position of the alignment mark 31 corresponding to the unit area 32 to be processed next before processing. Even if the substrate 30 is strained due to the processing of one unit area 32, the position of the alignment mark 31 of the substrate 30 after the strain is detected immediately before the processing of the unit area 32 to be processed next. Since the processing point 33 is processed based on the detection result of the position of the alignment mark 31, the influence of the strain of the substrate 30 can be reduced. As a result, it is possible to reduce the deviation between the original position of the processing point 33 and the actual processing position in the processing surface of the substrate 30.

Next, an example for reducing the influence of strain will be described. For example, the control device 20 acquires information (strain information) related to the strain of the substrate 30 based on the detection result of the position of the alignment mark 31 of the substrate 30 after the strain occurs. The control device 20 corrects the position defined by the position information of the processed point 33 stored in the storage device 21 according to the strain information of the substrate 30, and incidents the laser beam to the corrected position of the processed point 33. With this, the laser beam can be incident on the original position to be processed, and the position accuracy of the processing can be improved.

In particular, when the through-holes are formed in the substrate 30, if the through-holes are formed, the suction force of the vacuum chuck will be reduced, so that the substrate 30 is likely to be strained. In addition, when the thickness of the substrate 30 is 0.04 mm or less, strain easily occurs on the substrate. Therefore, when a process of forming a through hole in a substrate with a thickness of 0.04 mm or less is performed, the remarkable effect of this embodiment can be obtained.

Next, referring to FIGS. 4 and 5, the relationship between the scannable range of the beam scanner 13 (FIG. 1) and the size of the unit area 32 will be described. FIG. 4 is a diagram showing an example of the relationship between the scannable range 35 of the beam scanner 13 and the size of the unit area 32. The beam scanner 13 can incident the laser beam to any point inside the scannable range 35 without moving the substrate 30. In the example shown in FIG. 4, at least one unit area 32 is located inside the scannable range 35. At this time, in step SA2 of FIG. 3, when processing the processing point 33 in one unit area 32, the processing is performed in a state where the substrate 30 is stationary without moving the stage 17. When the processing of one unit area 32 is completed, it is only necessary to move the stage 17 when the position of the alignment mark 31 is detected in step SA1.

FIG. 5 is a diagram showing another example of the relationship between the scannable range 35 of the beam scanner 13 and the size of the unit area 32. In the example shown in FIG. 5, the unit area 32 is larger than the scannable range 35. At this time, in step SA2 of FIG. 3, when processing the processing point 33 in one unit area 32, processing the processing point 33 in the scannable range 35 is performed. Then, the stage 17 is moved, and the area where the unprocessed to-be-processed points 33 in the unit area 32 under processing are distributed may be arranged within the scannable range 35.

The embodiments shown in FIGS. 1 to 3 can be applied to any of the case where the scannable range 35 is greater than the unit area 32 and the case where the unit area 32 is greater than the scannable range 35.

Next, other embodiments will be described with reference to FIG. 6. FIG. 6 is a top view of the substrate 30 processed by the processing method based on other embodiments. In the embodiment shown in FIG. 2, a plurality of alignment marks 31 corresponding to the unit areas 32 are arranged inside the unit area 32. In the embodiment shown in FIG. 6, a part of the alignment mark 31 is arranged on the virtual boundary line of the adjacent unit area 32. That is, one alignment mark 31 is shared among the plurality of unit areas 32. As in this embodiment, one alignment mark 31 may be associated with a plurality of unit areas 32.

Next, referring to FIGS. 7 and 8, another embodiment will be further described. Hereinafter, the description of the configuration common to the embodiments shown in FIGS. 1 to 3 will be omitted. 7 is a plan view of the substrate 30 to be processed in the processing method according to this embodiment. In the embodiment shown in FIG. 2, the processed surface of the substrate 30 is divided into a plurality of unit regions 32. In the embodiment shown in FIG. 7, the processed surface is not divided into unit areas 32, and a plurality of alignment marks 31 are arranged in the processed surface of the substrate 30.

FIG. 8 is a flowchart of the processing method based on this embodiment. First, the control device 20 detects the position of at least a part of the alignment mark 31 (step SB1). Based on the detection result of the position of the alignment mark 31 just now, the processing of the processing point 33 to be processed next is performed (step SB2). If the processing of one processing point 33 ends, it is determined whether the processing of all processing points 33 has ended (step SB3). When there are still unprocessed points 33 to be processed, it is determined whether the control device 20 re-detects the position of the alignment mark 31 (step SB4). For example, the re-detection may be performed when a predetermined number of processed points 33 have been processed from the point of time when the position of the alignment mark 31 is detected. In addition, re-detection can be performed when a predetermined time has elapsed from the moment when the position of the alignment mark 31 is detected.

When the position of the alignment mark 31 is not re-detected, the processed point 33 to be processed next is processed according to the result of the detection of the position of the alignment mark 31 (step SB2). When re-detecting the position of the alignment mark 31, at least a part of the position of the alignment mark 31 is detected (step SB1). Then, the processing of the processing point 33 to be processed next is performed (step SB2). At this time, the alignment mark 31 at a part of the detection position is not limited to the same as the alignment mark 31 at a part of the previous detection position. Generally, at least one of the detected alignment marks 31 is different from the previously detected alignment marks 31.

The processing of the processing point 33 and the processing of re-detecting the position of the alignment mark 31 are repeated alternately until the processing of all the processing points 33 is completed.

In step SB1, in the process of detecting the position of at least a part of the alignment mark 31, it is desirable to select the position to be detected in such a manner as to define the position of the substrate 30 and the posture in the rotation direction perpendicular to the axis of the processed surface之Alignment mark 31. In addition, it is preferable to select the alignment mark 31 of the detection target so that the strain of the substrate 30 can be measured. Also, it is preferable to select the alignment mark 31 close to the position of the processing point 33 to be processed next. For example, it is desirable to sequentially detect the positions of a plurality of, for example, four alignment marks 31 in order of approaching the processing point 33 to be processed next.

As described above, in the present embodiment, during the processing of the plurality of processed points 33 in sequence, the position of at least a part of the alignment mark 31 is detected. The processed point 33 to be processed after detecting the position of the alignment mark 31 is processed according to the detection result just before the processing.

Next, the excellent effects of the embodiments shown in FIGS. 7 and 8 will be described. In this embodiment, the position of at least a part of the alignment mark 31 is detected during the processing of the plurality of processed points 33 in sequence. In the subsequent processing, the processing point 33 is processed based on the detection result of the position of the alignment mark 31 just detected. In this way, compared with the method of detecting the position of the alignment mark 31 only once before processing, the position of the processing point 33 can be corrected by taking into consideration the strain before the substrate 30 becomes larger. As a result, it is possible to reduce the deviation between the position of the processing point 33 to be processed originally and the position of the actual processing.

In order to reduce the positional deviation, the alignment mark 31 as a part of the detection position should be adopted in sequence in the order of approaching the processing point 33 to be processed next. In order to obtain information related to the strain of the substrate 30, it is preferable to set the number of alignment marks 31 at the detection position to four or more.

Next, referring to FIGS. 9A to 9D, a processing method according to another embodiment will be further described. 9A is a cross-sectional view of the substrate 30 before processing. The substrate 30 is held on the stage 17. The substrate 30 is a copper-clad laminate formed by bonding copper foils 41 and 42 on both sides of a core layer 40 made of resin, respectively. The surface of one of the copper foils 41 is called an upper surface, and the surface of the other copper foil 42 is called a lower surface. The substrate 30 is provided with an alignment mark 31 composed of a through-hole extending from the lower surface to the upper surface. The positions of the plurality of processed points 33 are set in advance on the upper and lower surfaces of the substrate 30. The position of the processed point 33 on the upper surface and the position of the processed point 33 on the lower surface are the same in the plane with respect to the substrate 30, and the position of the processed point 33 is stored in the storage device 21 of the control device 20.

9B is a cross-sectional view of the substrate 30 after processing the upper surface of the substrate 30. The control device 20 detects the position of the alignment mark 31, and sequentially enters the laser beam to the processing point 33 according to the detection result (FIG. 9A). With this, the concave portion 45 is formed at the processing point 33. The recess 45 penetrates the copper foil 41 to reach the core layer 40.

9C is a cross-sectional view of the substrate 30 after the front and back surfaces of the substrate 30 are reversed. The copper foil 41 on the upper side is in close contact with the stage 17, and the surface of the copper foil 42 on the lower side faces upward. The control device 20 detects the position of a part of the alignment mark 31 in this state.

9D is a cross-sectional view of the substrate 30 after processing the lower surface of the substrate 30. The control device 20 sequentially enters the laser beam into the plurality of processed points 33 on the lower surface of the substrate 30 (FIG. 9A ). At this time, the processing method based on the embodiment shown in FIG. 3 or FIG. 8 is adopted. By forming the concave portion at the processed point 33 on the lower surface, the through hole 46 is formed by being connected to the concave portion 45 (FIG. 9B) formed on the upper surface.

Next, the excellent effects of the embodiments shown in FIGS. 9A to 9D will be described. In this embodiment, even if the substrate 30 is formed with a through hole 46 (FIG. 9D) and the substrate 30 is strained, the position between the incident laser beam and the original position of the processed point 33 can be reduced Of deviation. Therefore, the concave portion 45 (FIG. 9B) formed on the upper surface and the concave portion formed on the lower surface can be connected to form the through-hole 46 (FIG. 9D ).

Next, a modification of this embodiment will be described. In this embodiment, in the processing of the processed point 33 (FIG. 9B) on the upper surface of the substrate 30, the processing method based on the embodiment shown in FIG. 3 or 8 is not used. This is because the through hole is not formed during the processing of the upper surface, and the strain of the substrate 30 should not increase. When it is assumed that the processing of the upper surface also increases the strain of the substrate 30, the processing method based on the embodiment shown in FIG. 3 or FIG. 8 is also preferably used for the processing of the upper surface. This can further reduce the positional deviation between the concave portion 45 (FIG. 9B) formed on the upper surface and the concave portion formed on the lower surface.

In this embodiment, first, a recess is formed on the upper surface of the substrate 30, and then the front and back surfaces of the substrate 30 are inverted to form a recess on the lower surface, thereby connecting the recess from the upper surface to the recess from the lower surface to form a through hole . The through hole may be formed at once by the incidence of the laser beam from the side of the substrate 30. At this time, when forming the through hole, it is preferable to use the processing method based on the embodiment shown in FIG. 3 or FIG. 8.

The above embodiments are examples, and of course, partial replacement or combination of the structures shown in different embodiments can be performed. The same effects based on the same structure of the plural embodiments are not mentioned sequentially in each embodiment. Furthermore, the present invention is not limited to the above-mentioned embodiments. Those skilled in the art should understand that various changes, improvements, combinations, etc., can be made, for example.

10‧‧‧Laser light source 11‧‧‧AOM 12‧‧‧Reflecting mirror 13‧‧‧ Beam Scanner 14‧‧‧Condenser lens 15‧‧‧beam damper 16‧‧‧Sensor 17‧‧‧ stage 20‧‧‧Control device 21‧‧‧Storage device 30‧‧‧ substrate 31‧‧‧Alignment mark 32‧‧‧ Unit area 33‧‧‧ processed point 35‧‧‧ Scanning range of beam scanner 40‧‧‧Core 41, 42‧‧‧ Copper foil 45‧‧‧recess 46‧‧‧Through hole

FIG. 1 is a schematic diagram of a laser processing apparatus based on an embodiment. 2 is a plan view of a substrate to be processed. FIG. 3 is a flowchart of a processing method based on an embodiment. 4 is a diagram showing an example of the relationship between the scannable range of the beam scanner and the size of the unit area. 5 is a diagram showing another example of the relationship between the scannable range of the beam scanner and the size of the unit area. 6 is a top view of a substrate processed by a processing method based on other embodiments. 7 is a plan view of a substrate to be processed in a processing method according to another embodiment. FIG. 8 is a flowchart of a processing method based on an embodiment for processing the substrate shown in FIG. 7. 9A is a cross-sectional view of the substrate before processing based on the processing method of another embodiment, FIG. 9B is a cross-sectional view of the substrate after processing the upper surface of the substrate, and FIG. 9C is a substrate after inverting the front and back surfaces of the substrate 9D is a cross-sectional view of the substrate after processing the lower surface of the substrate.

Claims (6)

A processing method, which includes the following processes: The processed points inside the plurality of unit areas of the substrate are processed, and the processed surface of the substrate is divided into the plurality of unit areas, and alignment marks are provided corresponding to the unit areas, inside the unit area Define the location of a plurality of processed points, Each of the processing of the unit area detects the position of the alignment mark corresponding to the unit area to be processed next, and performs processing of the processed point according to the detection result. The processing method as described in item 1 of the patent application scope, in which After detecting the position of the alignment mark, the strain information indicating the strain of the substrate is obtained based on the detection result of the position of the alignment mark, the position of the processed point is corrected based on the strain information, and the processing of the processed point is performed At this time, the processing is performed based on the corrected position of the processing point. A processing device having: Laser light source, output laser beam; A beam scanner, incident the laser beam output from the laser light source on the surface of the substrate, and moving the incident position on the surface of the substrate; Sensors to detect alignment marks provided on the aforementioned substrate; and In the control device, the processed surface is divided into a plurality of unit areas, and the positions of the plurality of processed points of the processed surface are stored. Each of the processing of the unit area is detected based on the detection result of the sensor The position of the alignment mark corresponding to the unit area to be processed next controls the beam scanner according to the detection result so that the laser beams are incident on the processed point in sequence. A processing method in which the following processes are repeated alternately multiple times: Detecting the position of the alignment mark of at least a part of the substrate, a plurality of the alignment marks are provided on the substrate and the positions of the plurality of processed points to be processed are defined, According to the detection result of the position of the aforementioned alignment mark, a part of the plurality of processed points is processed in sequence. The processing method as described in item 4 of the patent application scope, in which After detecting the position of the alignment mark, the strain information indicating the strain of the substrate is obtained based on the detection result of the position of the alignment mark, the position of the processed point is corrected based on the strain information, and the processing of the processed point is performed At this time, the processing is performed based on the corrected position of the processing point. A processing device having: Laser light source, output laser beam; A beam scanner, incident the laser beam output from the aforementioned laser light source on the processed surface of the substrate, and moving the incident position on the surface of the aforementioned substrate; A sensor to detect each of the plurality of alignment marks provided on the aforementioned substrate; and The control device stores the positions of the plurality of processed points on the processed surface, and controls the laser light source and the beam scanner according to the detection result of the sensor, The aforementioned control device repeats the following processing alternately a plurality of times: Detecting at least a part of the position of the alignment mark based on the detection result of the sensor, The laser light source and the beam scanner are controlled based on the detection result of the position of the alignment mark, and a part of the plurality of processed points is processed in sequence.

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