TW201336608A - Laser processing device and laser processing method - Google Patents

Abstract

The present invention provides a laser processing device that can be used to shorten the time required for the determination of whether there is a poor processing. A laser beam emitting from a laser light source is incident to a processed object through a beam scanner, and the incident point of the laser beam is moved in the scanning range. A camera device photographs a portion of a surface area of the processed object to obtain image data. A control device controls an object stage and makes a first region of the processed object move in the scanning range for controlling the beam scanner to allow the laser beam to be incident to the first region for laser processing. During the laser processing in the first region, the camera device is controlled in order to get the image data of a second region, which is different from the first region and has already completed laser processing, on the surface of the processed object.

Description

Laser processing device and laser processing method

The present invention relates to a laser processing apparatus and a laser processing method for performing laser processing by sequentially projecting a laser beam onto a plurality of processing points on an object to be processed.

A technique in which a pulsed laser beam is incident on a processing object such as a printed board and is drilled is known. Typically, the pulse of a pulsed laser beam can be biased, sometimes producing a laser pulse that is less than the average pulse energy. If a laser pulse having a pulse energy lower than the lower limit of the pulse energy required for the drilling process is generated, a machining failure occurs.

In the method disclosed in Patent Document 1, after the laser beam is incident on the substrate and drilled, the position of the drilling process is photographed by a CCD camera to confirm whether or not the hole is formed at a desired position. Further, the cross-sectional shape of the formed hole is confirmed by moving the substrate in the vertical direction while scanning the vicinity of the processed portion by the observation laser beam.

In the method disclosed in Patent Document 2, when a laser beam is incident on a substrate via a scanning mirror, an image of the processed portion is acquired by receiving, by the imaging device, light propagating in the opposite direction via the scanning mirror. Whether or not the drilling process is finished is determined by analyzing the acquired image.

Patent Document 1: Japanese Laid-Open Patent Publication No. 2001-121279

Patent Document 2: Japanese Laid-Open Patent Publication No. 2004-223553

After the drilling process, it is necessary to confirm the cross-sectional shape of the hole by the scanning of the laser beam and the vertical movement of the substrate. In the method of acquiring an image of a processed portion when a laser beam is incident, since the influence of the laser beam used for processing cannot be excluded, it is difficult to observe the shape of the hole with high precision.

An object of the present invention is to provide a laser processing apparatus and a laser processing method capable of shortening a required time for determining the presence or absence of a machining failure.

According to one aspect of the present invention, there is provided a laser processing apparatus comprising: a stage for holding an object to be processed and moving the object to be processed in a direction parallel to a surface thereof; a laser source; a beam scanner a laser beam emitted from the laser light source is incident on the object to be processed, and an incident point of the laser beam is moved within a scannable range; and an imaging device captures a part of a surface of the object to be imaged And a control device that controls the stage, the laser light source, the beam scanner, and the imaging device; the control device controls the stage to cause the first region of the object to be processed Moving within the scan range, controlling the aforementioned beam scanner and directing the laser beam to the aforementioned first region Laser processing is performed by internal incidence, and during the laser processing in the first region, the imaging device is controlled to acquire a second region in which the laser processing is completed different from the first region on the surface of the object to be processed. Image data.

According to another aspect of the present invention, there is provided a laser processing method comprising: a process of performing laser processing by causing a laser beam to be incident on a plurality of processing points in a first region of an object to be processed; and in the first region In the laser processing, a process of completing the image of the second region of the laser processing is performed, and an image of the second region is analyzed to detect a process of the defective portion.

The processing of the object to be processed is simultaneously performed with the shooting of the processed area, so that the time required for processing and shooting can be shortened.

10‧‧‧stage

11‧‧‧Mobile agencies

12‧‧‧Processing objects

13‧‧‧Abutment

15‧‧‧Control device

16‧‧‧Laser light source

17‧‧‧ Beam shaping optical system

18‧‧‧Reflective mirror

19‧‧‧beam scanner

20‧‧‧f θ lens

21‧‧‧ scanable range

25‧‧‧Photographing device

26‧‧‧ Lifting mechanism

27‧‧ Sight

28‧‧‧ Input device

29‧‧‧Display device

30‧‧‧Scanning area

31‧‧‧ hole

35‧‧‧Substrate

36‧‧‧ Inner copper pattern

37‧‧‧ resin film

38‧‧‧Surface copper film

41‧‧‧y direction linear guide

42‧‧‧x direction linear guide

43‧‧‧Photographing mechanism

45‧‧‧Image of the opening of the hole

46‧‧‧Image of the bottom of the hole

50‧‧‧ input button

Fig. 1 is a schematic view showing a laser processing apparatus of an embodiment.

Fig. 2 is a plan view of the object to be processed.

Fig. 3 is a schematic view showing the relative positional relationship between the imaging device, the lifting device, and the object to be processed.

4A and 4B are schematic views showing the positional relationship between the beam scanner and the imaging device.

Fig. 5 is a plan view of the object to be processed.

Fig. 6A shows the serial number of the scanning area divided by the object to be processed Fig. 6B is a timing chart of processing and photographing of the scanning area when processing is performed by the method of the embodiment, and Fig. 6C is a timing chart of processing and photographing of the scanning area when processing is performed based on the method of the comparative example. .

Figure 7 is a flow chart of a laser processing method of an embodiment.

Fig. 8 is a schematic view showing an image and an input device of the display device.

Fig. 1 is a schematic view showing a laser processing apparatus of an embodiment. An object 12 to be processed such as a printed board is held on the holding surface of the stage 10. The moving mechanism 11 is mounted on the base 13. The moving mechanism 11 is controlled from the control device 15 to move the stage 10 in a direction parallel to the surface of the object 12 to be processed. For example, the moving mechanism 11 is supported by the base 13 so that the holding surface of the stage 10 and the surface of the object 12 are horizontal. The xyz orthogonal coordinate system is defined as follows. The two directions parallel to the holding surface and orthogonal to each other are defined as the x direction and the y direction, and the normal direction of the holding surface is defined as the z direction.

The laser source 16 emits a pulsed laser beam. As the laser light source 16, a carbon dioxide laser, a YAG laser or the like is used. The laser beam emitted from the laser source 16 is calibrated by shaping the beam section by the beam shaping optical system 17. The calibrated laser beam is incident on the object 12 via the refracting mirror 18, the beam scanner 19, and the f θ lens 20.

The f θ lens 20 images the beam cross-sectional shape of the mask position in the beam shaping optical system 17 on the surface of the object 12 to be processed. The beam scanner 19 is controlled from the control device 15 on the surface of the object 12 to be processed. The incident point of the laser beam is moved in the x direction and the y direction. The movable range of the incident point of the laser beam is referred to as a "scannable range" 21. The beam scanner 19 is composed of, for example, a current scanner for x and a current scanner for y.

The imaging device 25 is disposed above the stage 10 . The elevating mechanism 26 is controlled from the control device 15 to move the imaging device 25 in the z direction. The imaging device 25 captures a part of the surface of the object 12 to acquire image data. The acquired image data is input to the control device 15. For example, a two-dimensional CCD camera is used in the imaging device 25. Further, as the imaging device 25, a line sensor can also be used. When the line sensor is used, a plurality of one-dimensional images are acquired while moving the object 12 in a direction orthogonal to the line direction of the line sensor. A plurality of 1-dimensional images can be assembled to obtain a 2-dimensional image.

The operator scans the input device 28 to give various commands (commands) to the control device 15. In the input device 28, for example, a keyboard, a pointing device, or the like is used. The control device 15 displays an image or the like on the display device 29. In the display device 29, for example, a liquid crystal display or the like is used.

FIG. 2 is a plan view of the object 12 to be processed. The position (machining point) at which the hole is to be formed is determined on the surface of the object 12. The position of the machining point is stored in the control device 15 (Fig. 1). Further, the surface of the object 12 is divided into a plurality of scanning regions 30. The one scanning region 30 has a scanable range 21 which is included in the beam scanner 19 and the f θ lens 20 (Fig. 1). The moving mechanism 11 is controlled to move the unprocessed scanning zone 30 within the scannable range 21 so that the laser beam can be illuminated at any of the processing points within its scanning zone 30. Making a plurality of scanning areas 30 The movement is moved within the scannable range 21 so that drilling can be performed at the machining points in all of the scanning zones 30. In the present specification, the process of performing drilling processing at a processing point in the scanning zone 30 is sometimes referred to as "processing of a scanning zone".

2 shows an example in which the x direction is the row direction and the y direction is the column direction, and the scanning area 30 is arranged in a matrix of 4 rows and 4 columns, but the number and arrangement of the scanning regions 30 depend on the processing target. The size of the object 12 and the size of the scannable range 21. In Fig. 2, the processing of all the scanning regions 30 from the negative side end of the y direction is completed, and for the row of the third row from the negative side in the y direction, two amounts from the negative side of the x direction are shown. The processing completion state of the scanning area 30. In the scanning area 30 where the processing is completed, a plurality of holes 31 are formed.

The field of view 27 of the imaging device 25 (Fig. 1) contains the size of one scanning zone 30. For example, the field of view 27 contains a scanning zone 30 of processing agent adjacent to the scanning zone 30 disposed within the scannable range 21. The control device 15 analyzes the image data of the scanning area 30 of the processing agent, thereby being able to determine the quality of the drilling process.

The control device 15 memorizes the relative positional relationship between the coordinates defined in the field of view 27 of the imaging device 25 and the coordinates defined within the scannable range 21. Therefore, the defective portion obtained by analyzing the image data can be associated with the processing point in the scannable range 21 1:1.

The relative positional relationship between the object 12, the imaging device 25, and the elevating mechanism 26 is shown in Fig. 3 . A cross-sectional view of the object 12 is shown in the lower half of Fig. 3. The substrate 35 made of glass epoxy is shaped An inner layer copper pattern 36 is formed. A resin film 37 is formed on the copper pattern 36 and the substrate 35. A surface copper film 38 is formed on the resin film 37. A plurality of holes (recesses) 31 are formed from the surface of the copper film 38 to the inner layer copper pattern 36. The distance from the imaging device 25 to the focus surface is set to F0.

When the elevating mechanism 26 raises and lowers the imaging device 25, the height from the object 12 to the imaging device 25 changes. When the depth of the hole 31 (the height from the bottom surface to the opening portion) is deeper than that of the imaging device 25, it is impossible to simultaneously focus on both the bottom surface and the opening portion of the hole 31. In the third drawing, when the imaging device 25 is placed at a position displayed by a solid line, the focal plane FSt of the imaging device 25 coincides with the opening of the hole 31. When the imaging device 25 is lowered and placed at a position shown by a broken line, the focal plane FSb of the imaging device 25 coincides with the bottom surface of the hole 31. In this manner, an image in which the opening of the hole 31 is focused and an image in which the bottom surface of the hole 31 is focused can be obtained by moving the imaging device 25 up and down.

The positional relationship between the beam scanner 19 and the imaging device 25 is shown in Fig. 4A. The beam scanner 19 is fixed relative to the base 13 (Fig. 1). The imaging device 25 can be moved in the x direction and the y direction with respect to the beam scanner 19 by the imaging device moving mechanism 43.

The imaging device moving mechanism 43 includes a y-direction linear guide 41 and an x-direction linear guide 42. The y-direction linear guide 41 is fixed to the base 13. The x-direction linear guide 42 is supported by the y-direction linear guide 41 and moves in the y direction. The imaging device 25 is supported by the linear guide 42 in the x direction and moves in the x direction. FIG. 4A shows a state in which the imaging device 25 is disposed on the negative side in the x direction with respect to the beam scanner 19. Instead, you can shoot The camera 25 is disposed on the positive side in the x direction with respect to the beam scanner 19. 4B shows a state in which the imaging device 25 is disposed on the negative side in the y direction with respect to the beam scanner 19.

An example of the processing order of the scanning area 30 is shown in FIG. In the example shown in Fig. 5, as indicated by the arrows, first, the processing of the scanning region 30 is sequentially performed in the positive direction of the x direction. When the processing of the scanning area 30 at the positive side end in the x direction is completed, the scanable range 21 is moved by one amount in the scanning direction toward the positive direction of the y direction. Next, the processing of the scanning region 30 is sequentially performed in the negative direction of the x direction. When the processing of the scanning area 30 at the negative side end in the x direction is completed, the scanable range 21 is moved by one amount in the scanning direction toward the positive direction of the y direction. Processing of all of the scanning zones 30 is performed by repeating this step.

While the processing of the scanning zone 30 is sequentially performed in the positive direction of the x direction, as shown in FIG. 4A, the imaging device 25 is placed on the negative side in the x direction with respect to the beam scanner 19. During the processing of the scanning zone 30 in the negative direction of the x direction, the imaging device 25 is placed on the positive side in the x direction with respect to the beam scanner 19. When the scanning range 21 is moved in the positive direction of the y direction by one amount, as shown in FIG. 4B, the imaging device 25 is placed on the negative side in the y direction with respect to the beam scanner 19. The photographing device 25 is disposed as described above with respect to the beam scanner 19, so that the scanning region 30 having finished processing can be photographed while the processing of the scanning region 30 is performed.

2 and 5 show the case where the field of view 27 is larger than the scanning area 30. When the field of view 27 is smaller than the scanning area 30, the processing is changed during the processing of the scanning area 30. The image of the imaging device 25 in the x direction and the y direction is imaged a plurality of times, and image data of all the holes 31 formed in one scanning area 30 can be acquired.

The processing sequence of the scanning area 30 and the imaging sequence of the imaging device 25 will be described with reference to FIGS. 6A and 6B.

Fig. 6A shows the relationship of the scanning area 30 to its attached serial number. If the row of the negative side end in the y direction is set to the first row, the sequence number is attached to the forward direction toward the x direction in the odd number of rows. In the positive side end of the x direction, the scanning area 30 adjacent to the positive side in the y direction is attached with the next serial number. In the even number of rows, the serial number is attached in ascending order in the negative direction toward the x direction. Among the negative side ends in the x direction, the scanning area 30 adjacent to the positive side in the y direction is attached with the next serial number.

A timing chart when laser processing and photographing are simultaneously performed is shown in Fig. 6B. The horizontal axis shows the elapsed time. During the laser processing of the i-th scanning area (first area) 30, the imaging of the (i-1)th scanning area (second area) 30 in which processing has been completed is simultaneously performed. Shooting is not possible during the processing of the first scanning zone 30. After the processing of the Nth scan area 30 having the largest serial number is completed, the photographing of the Nth scan area 30 is performed. If the time required for processing one scanning zone 30 is Tm and the time required for imaging of one scanning zone 30 is Ti, the time required for processing and shooting of the N scanning zones 30 is roughly It is equal to Tm×N+Ti. In addition, the moving time of the object 12 is not considered.

Fig. 6C shows a timing chart when processing and photographing are carried out by the method of the comparative example. In the comparative example, after the processing of all the scanning areas 30 is completed, The shooting of each scanning area 30 is performed. In this method, the time required for processing and photographing the N scanning regions 30 is approximately equal to Tm × N + Ti × N.

As in the embodiment, processing and photographing are simultaneously performed, so that the time required for processing and photographing can be shortened.

A flow chart of the laser processing method of the embodiment is shown in FIG. In step S1, as shown in Fig. 6B, processing and photographing of the scanning area 30 are simultaneously performed. In step S2, the control device 15 (first drawing) automatically analyzes the image acquired by the imaging device 25, and detects a defective portion. The quality of the processing is determined by determining whether, for example, the diameter of the opening of the hole 31 and the diameter of the bottom surface shown in Fig. 3 are within an allowable range.

In step S3, the control device 15 displays an image of the portion determined to be defective in processing on the display device 29 (first drawing).

An example of an image displayed on the display device 29 is shown in FIG. An opening image 45 of the hole 31 and an image 46 of the bottom surface are displayed on the display screen. In addition, the "need to correct" and "do not need to correct" input buttons are also displayed in the same plane.

In step S4, the operator observes the displayed image to determine whether or not correction processing is required. When it is determined that the correction processing is necessary, the input device 28 is operated to notify the control device 15 of the need for the correction processing. When it is determined that the correction processing is not required, the input device 28 is operated to notify the control device 15 that the correction processing is not required. As an example, the operator notifies the control device 15 by selecting a button "need to correct" or "no need to correct" on the drawing by operating the positioning device.

When it is notified that correction processing is required, the control device 15 in step S5 The coordinates of the processing points that need to be corrected are recorded in the correction processing table. When the recording is completed, in step S6, it is determined whether or not the correction is necessary for all the defective portions detected in step S2. In step S4, when it is determined that the correction processing is unnecessary, step S6 is executed without executing step S5. When the undetermined defective portion remains, the process returns to step S3 to process the undetermined defective portion. When the determination of all the defective parts is completed, the correction processing of the defective part to be corrected on the correction processing table is performed in step S7. For example, in the correction process, additional laser irradiation is performed on the defective portion.

In the embodiment, the processing and imaging of the scanning area 30 (Fig. 2) are simultaneously performed in step S1, so that the time until the correction processing is completed can be shortened. Further, in step S4, the operator determines whether or not the correction processing is necessary. Therefore, it is possible to prevent additional laser irradiation from being performed at a portion where correction is not required.

In the above embodiment, all the processing points in the scanning area 30 (Fig. 2) were photographed, but only a part of the processing points may be photographed. For example, when the field of view 27 (Fig. 2) of the photographing device 25 (Fig. 1) is smaller than the scan area 30, a part of the area in the scan area 30 is photographed to acquire image data. In step S2 (Fig. 7), the image data is analyzed, and the processing is automatically determined only for the processing points included in the image data. From this determination result, it is possible to statistically estimate the processing quality of all the regions.

The present invention has been described based on the above examples, but the present invention is not limited to these. For example, it is obvious to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

30‧‧‧Scanning area

Claims (9)

A laser processing apparatus comprising: a stage for holding an object to be processed and moving the object to be parallel to a surface thereof; a laser source; a beam scanner for causing a laser source from the laser light source The emitted laser beam is incident on the object to be processed, and the incident point of the laser beam is moved within a scannable range; and the photographing device photographs a part of the surface of the object to obtain image data; a control device that controls the stage, the laser light source, the beam scanner, and the imaging device; and the control device controls the stage to move the first region of the object within the scannable range Controlling the beam scanner and subjecting the laser beam to the first region to perform laser processing, and during the laser processing in the first region, controlling the imaging device to acquire the surface of the object to be processed The image data of the second region of the laser processing has been completed differently from the first region. The laser processing apparatus according to claim 1, wherein the control device has information on a relative positional relationship between a coordinate in a field of view of the imaging device and a coordinate in the scannable range. A laser processing apparatus according to claim 1 or 2, wherein The imaging device has a function of moving the focus surface in a direction perpendicular to the surface of the object to be processed. The laser processing apparatus according to claim 3, wherein the laser beam is incident on the object to be processed, and a concave portion is formed in the object to be processed, and the control device performs the processing target During the laser processing in the region, the focal plane of the imaging device is aligned with the opening formed in the concave portion of the second region to acquire the first image data, and the focal plane of the imaging device is aligned with The second image data is acquired on the bottom surface of the concave portion of the second region. The laser processing apparatus of claim 1 or 2, wherein the apparatus further has a moving mechanism that causes one of the imaging device and the beam scanner to be parallel to the other direction The direction of the surface of the object to be processed moves. The laser processing apparatus according to claim 1 or 2, wherein the apparatus further comprises a display device; and an input device for inputting an instruction by an operator, wherein the control device performs the aforementioned acquisition by the camera device Image analysis of the second area image data, detecting a defective portion, and displaying an image of the detected defective portion on the display device. The additional irradiation of the laser beam is performed by the operator notifying the defective portion requiring the correction processing through the input device. A laser processing method characterized by having a process of performing laser processing by causing a laser beam to be incident on a plurality of processing points in a first region of a workpiece, and performing a laser processing in the first region During the shot processing, a process of ending the image of the second region of the laser processing is performed; the image of the second region is analyzed, and the process of the defective portion is detected. The laser processing method according to claim 7, wherein in the process of performing the laser processing, a concave portion is formed by incidence of a laser beam, and in the process of acquiring the image, the focus is faced. The first image is acquired by the opening of the concave portion, the second image is obtained by aligning the focal plane with the bottom surface of the concave portion, and the first image and the second image are analyzed during the process of detecting the defective portion. image. The laser processing method according to claim 7 or 8, wherein the method further performs an additional laser irradiation by detecting a defective portion detected in the process of the defective portion.