JP6898551B2 - Laser processing equipment and laser processing method - Google Patents

Description

The present invention relates to a laser processing apparatus and a laser processing method, and more particularly to a technique for processing an workpiece by a laser beam induced by a liquid jet.

In recent years, with the increasing integration and miniaturization of devices such as ICs and LSIs, inorganic films such as SiOF and BSG (SiOB) and polymer films such as polyimide and parylene have been applied to the surface of semiconductor substrates such as silicon. A wafer having a device layer formed of a laminated body in which a low-dielectric-constant insulator film (Low-k film) made of a certain organic film and a functional film forming a circuit are laminated has been put into practical use.

However, dicing of a wafer having such a device layer tends to cause film peeling, burrs, and the like, which is a big problem in the dicing process. In particular, when the low-k film is contained in the device layer, the low-k film is very brittle, so that there is a problem that the low-k film is likely to be peeled off when the dicing blade is used for cutting. That is, when cut by a dicing blade, the Low-k film is destroyed, and when this destroyed region spreads to the device forming region (chip forming region), the chip becomes a defective product and the yield of the manufactured semiconductor device is lowered. It becomes a factor to end up.

In order to solve the above problem, a technique for forming a laser processing groove along a planned division line called a street to divide a device layer and then cutting with a dicing blade prior to cutting with a dicing blade is disclosed. (See, for example, Patent Document 1).

However, the technique disclosed in Patent Document 1 requires a laser processing device (laser scriber) in addition to the dicing device. Further, in the laser irradiation step, in order to form a laser processing groove wider than the width of the dicing blade, the laser irradiation must be reciprocated along one street. Therefore, there is a problem that productivity is poor and cost is increased.

On the other hand, Patent Document 2 discloses a laser processing apparatus that injects a pressurized liquid with a liquid jet and irradiates a work piece with laser light using the pressurized liquid as an optical waveguide. In this laser machining device, since the liquid jet is ejected toward the workpiece, the laser beam is guided toward the workpiece without being diffused by the liquid jet while preventing the effects of heat damage and contamination during machining. Therefore, it is possible to perform high-precision machining. In addition, a dicing step such as dicing with a dicing blade or laser dicing becomes unnecessary.

Japanese Unexamined Patent Publication No. 2006-140311 Japanese Unexamined Patent Publication No. 2016-193453

By the way, when the workpiece is processed by the laser beam induced by the liquid jet, there is a problem that the processing shape changes even if the processing conditions (for example, the length of the liquid jet) are slightly different.

To solve this problem, the laser processing device disclosed in Patent Document 2 includes a laser light distribution observation device for observing the distribution of laser light guided by a liquid jet. In this laser light distribution observation device, since the shielding plate and the photodetector are arranged in a positional relationship conjugate with each other with respect to the imaging lens, the distribution of laser light on the contact surface between the liquid jet and the shielding plate is detected. It can be faithfully reproduced on the light receiving surface of the device. This makes it possible to observe the distribution of the laser beam guided by the liquid jet.

However, in the laser processing apparatus disclosed in Patent Document 2, in order to obtain an arbitrary processing shape (target processing shape), it is necessary to manually repeat the adjustment of the laser light distribution in the liquid jet and the evaluation of the processing shape for several cycles. Therefore, there is a problem that it takes time and effort to make a judgment to obtain the target processing shape.

The present invention has been made in view of such circumstances, and when processing a work piece by a laser beam induced by a liquid jet, it is possible to reduce judgment, labor, and time until a target processing shape is obtained. It is an object of the present invention to provide a laser processing apparatus and a laser processing method.

In order to achieve the above object, the laser processing apparatus according to the first aspect of the present invention includes a laser oscillator, a processing head that irradiates a workpiece while guiding the laser light output from the laser oscillator with a liquid jet. A moving means for relatively moving the processing head and the work piece, a laser light distribution observation means for observing the laser light distribution in the liquid jet on the laser light irradiation surface of the work piece, and a laser light distribution observation means for observation. It is provided with a predicted machining shape calculation means for calculating a predicted machining shape when the workpiece is machined by the machining head based on the laser beam distribution.

In the first aspect, the laser processing apparatus according to the second aspect of the present invention has a high-speed deflection means that deflects the laser beam at high speed on the way from the laser oscillator to the processing head, and the processing head and the workpiece are relative to each other by the moving means. A high-speed deflection control means for switching the laser beam distribution to a plurality of distributions by changing the deflection conditions of the high-speed deflection means when irradiating the workpiece with the laser beam from the machining head while moving the laser beam. The predicted processing shape calculation means processes the workpiece by the processing head while switching the laser light distribution to a plurality of distributions by the high-speed deflection control means based on the plurality of distributions of the laser light observed by the laser light distribution observing means. Calculate the expected machining shape of the case.

In the second aspect, the laser processing apparatus according to the third aspect of the present invention includes a low-speed deflection means for deflecting the laser beam output from the laser oscillator toward the processing head, and the high-speed deflection means is more than the low-speed deflection means. Performs high-speed deflection and narrow range deflection.

In the laser processing apparatus according to the fourth aspect of the present invention, in the second or third aspect, the high-speed deflection means is an acoustic-optical deflection element.

In the laser processing apparatus according to the fifth aspect of the present invention, in any one of the second to fourth aspects, the high-speed deflection control means has the processing head and the workpiece at the peak position of the laser light in the laser light distribution. The deflection condition of the high-speed deflection means is changed so that the scanning is performed in a direction orthogonal to the movement direction relative to the above.

The laser machining apparatus according to the sixth aspect of the present invention compares the predicted machining shape calculated by the predictive machining shape calculation means with the target machining shape of the workpiece in any one of the first to fifth aspects. A laser beam distribution adjusting means for adjusting the laser beam distribution is provided based on the above.

In the sixth aspect, the laser processing apparatus according to the seventh aspect of the present invention includes a processing shape measuring means for measuring the processing shape formed by the processing head, and the laser light distribution adjusting means is measured by the processing shape measuring means. The laser beam distribution is adjusted based on the comparison between the processed shape and the target processed shape of the workpiece.

The laser processing method according to the eighth aspect of the present invention includes a laser beam irradiation step of irradiating a work piece with a laser beam guided by a liquid jet, and a moving step of relatively moving the liquid jet and the work piece. Based on the laser light distribution observation step for observing the laser light distribution in the liquid jet on the laser light irradiation surface of the work piece and the laser light distribution observed in the laser light distribution observation step, the work piece is processed with laser light. It is provided with an expected processing shape calculation step for calculating an expected processing shape when the above is applied.

According to the present invention, when the workpiece is processed by the laser beam induced by the liquid jet, the expected processing shape can be easily grasped from the laser beam distribution in the liquid jet, so that the target processing shape can be obtained. Judgment, labor, and time can be reduced. As a result, it is possible to reduce the work man-hours and improve the production efficiency by shortening the time required for laser machining, and it is possible to obtain the target machining shape with high accuracy.

The schematic diagram which shows the structure of the laser processing apparatus which concerns on 1st Embodiment Simplified diagram showing the laser beam path in a liquid jet The figure which showed the result of observing the distribution of the laser beam at the position shown by a of FIG. The figure which showed the result of observing the distribution of the laser beam at the position shown by b of FIG. The figure which showed the depth profile of the machined groove when the linear machined groove was formed in the work under the same conditions as FIG. The figure which showed the depth profile of the machined groove when the linear machined groove was formed in the work under the same conditions as FIG. Explanatory drawing schematically showing the case where laser processing is performed with the laser light distribution in the liquid jet constant. Explanatory drawing schematically showing the case where laser processing is performed while switching the laser light distribution in the liquid jet to a plurality of distributions. Explanatory drawing schematically showing the case where laser processing is performed while switching the laser light distribution in the liquid jet to a plurality of distributions. Explanatory drawing schematically showing the case where laser processing is performed while switching the laser light distribution in the liquid jet to a plurality of distributions. The figure for demonstrating the processing result at the time of performing laser processing while switching the laser light distribution in a liquid jet between two distributions by a high-speed deflection means. The figure for demonstrating the processing result at the time of performing laser processing while switching the laser light distribution in a liquid jet between two distributions by a high-speed deflection means. The figure for demonstrating the processing result at the time of performing laser processing while switching the laser light distribution in a liquid jet between two distributions by a high-speed deflection means. A flowchart showing an example of a laser processing method using the laser processing apparatus according to the first embodiment. Diagram showing an example of a reference table The figure which showed the 1st example of the calculation method of the expected processing shape The figure which showed the 1st example of the calculation method of the expected processing shape The figure which showed the 2nd example of the calculation method of the expected processing shape The figure which showed the 2nd example of the calculation method of the expected processing shape The figure which showed the 2nd example of the calculation method of the expected processing shape The figure which showed the 3rd example of the calculation method of the expected processing shape The figure which showed the 3rd example of the calculation method of the expected processing shape The figure which showed the 3rd example of the calculation method of the expected processing shape A log-log graph showing an example of the correspondence between irradiation fluence and processing rate Conceptual diagram for explaining a laser machining method in a case where laser machining is performed in a state where the laser beam distribution in a liquid jet is constant in one machining path. The schematic diagram which shows the structure of the laser processing apparatus which concerns on 2nd Embodiment Diagram for explaining the effect of phase adjustment by a spatial optical phase modulator The schematic diagram which shows the structure of the laser processing apparatus which concerns on 3rd Embodiment The figure for demonstrating the effect of the 3rd Embodiment The figure for demonstrating the effect of the 3rd Embodiment

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

(First Embodiment)
FIG. 1 is a schematic view showing the configuration of the laser processing apparatus 10 according to the first embodiment.

As shown in FIG. 1, the laser processing apparatus 10 includes a laser power supply 12, a laser oscillator 14, a work table 16, a work table moving unit 18, a liquid supply means 20, a head unit 22, and a laser beam distribution observation. It includes a device 26 and a control unit 30.

The laser power supply 12 is connected to the laser oscillator 14 via a signal cable to supply electric power to the laser oscillator 14.

The laser oscillator 14 outputs the laser beam L using the electric power supplied from the laser power supply 12. As the laser beam L, a laser beam in a wavelength range that is difficult to be absorbed by water is used.

The work table 16 has a holding surface 16a that attracts and holds the work W (workpiece). The holding surface 16a is provided with a plurality of suction holes for sucking and holding the work W, and the suction holes are connected to a vacuum suction source (not shown).

The work table moving unit 18 includes an X table 32 and a θ rotation table 34. The X table 32 is installed horizontally and is configured to be movable in the X direction by an X drive mechanism (not shown). The θ rotary table 34 is arranged on the X table 32 and is configured to be movable in the θ direction (rotation direction centered on the axis in the Z direction) by a θ drive mechanism (not shown). Then, the work table 16 is placed and fixed on the θ rotary table 34. Therefore, the work table 16 is configured to be movable in the X direction and the θ direction, respectively. The work table moving unit 18 is an example of moving means.

The liquid supply means 20 is connected to the processing head 40 of the head unit 22 via a liquid supply path, and supplies a pressurized liquid (for example, pressurized water) to the processing head 40.

The head unit 22 includes a deflection portion 36, a beam shape shaping means 38, and a processing head 40. The head unit 22 is arranged on a Z table configured to be movable in the Z direction by a Z drive mechanism (not shown). The Z table is arranged in a Y table configured to be movable in the Y direction by a Y drive mechanism (not shown). Therefore, the head unit 22 is configured to be movable in the Y direction and the Z direction.

The deflection unit 36 is provided on the optical path of the laser beam L, and reflects the laser beam L output from the laser oscillator 14 toward the processing head 40. The deflection unit 36 is configured by facing two galvano mirrors (not shown) that can swing around axes orthogonal to each other, and swings the two galvano mirrors to deflect the laser beam L. Therefore, the incident angle and the incident position with respect to the liquid jet J ejected from the processing head 40 (liquid jet injection nozzle 48) can be changed. The deflection unit 36 is an example of low-speed deflection means.

The beam shape shaping means 38 is arranged between the deflection unit 36 and the processing head 40, and shapes the laser beam L input from the laser oscillator 14 via the deflection unit 36. The beam shape shaping means 38 is composed of, for example, a variable aperture (rectangular or circular), an axicon lens, a beam homogenizer, and a mechanism for minutely moving these in a direction orthogonal to the laser beam L. The laser beam L before being incident on is shaped into a predetermined shape, size, and intensity distribution. Further, using an AOD (acoustic optical deflection element), SLM (spatial modulation element), DMD (Digital Mirror Device), diffraction element, calcite, etc., the laser beam L is statically or dynamically including the branching of the laser beam L. It is also possible to shape.

The processing head 40 injects the pressurized liquid supplied from the liquid supply means 20 toward the work W by the liquid jet J, and guides the laser beam L into the liquid jet J to guide the liquid jet J. The work W is irradiated with the laser beam L guided by the above. The specific configuration of the processing head 40 is as follows.

The processing head 40 includes a condenser lens 42 and a head body 44.

The condensing lens 42 is arranged in the front stage (upper side) of the head main body 44, and condenses the laser light L incident from the laser oscillator 14 via the deflection portion 36 and the beam shape shaping means 38 toward the inside of the head main body 44. To do.

A liquid chamber 46 is partitioned inside the head body 44. The liquid chamber 46 accommodates the high pressure liquid supplied from the liquid supply means 20. A liquid jet injection nozzle 48 is provided in the lower part of the head body 44, and the liquid jet injection nozzle 48 communicates with the liquid chamber 46. Therefore, when the high-pressure liquid is supplied from the liquid supply means 20 to the processing head 40, the pressurized liquid is housed in the liquid chamber 46, and the work W (or laser beam distribution observation described later) is further observed from the liquid jet injection nozzle 48. The liquid jet J is ejected toward the shielding plate 52) of the device 26.

A window portion 50 is provided on the upper portion of the head main body 44. The window portion 50 is composed of a light transmitting member (for example, quartz glass) that is optically transparent to the laser light L, seals the liquid chamber 46, and transmits the laser light L. Therefore, the laser beam L emitted from the condenser lens 42 passes through the window portion 50, enters the inside of the head body 44 (liquid chamber 46), and is focused on the liquid jet injection nozzle 48.

In the present embodiment, as an example, the work table 16 is configured to be movable in the X direction and the θ direction, and the head unit 22 is configured to be movable in the Y direction and the Z direction. It suffices that the 16 and the head unit 22 are relatively movable in the X direction, the Y direction, the Z direction, and the θ direction, and other embodiments different from the present embodiment can be appropriately adopted. The same applies to other embodiments described later.

The laser beam distribution observation device 26 observes the distribution (laser beam distribution) of the laser beam L in the liquid jet J on the surface (laser beam irradiation surface) of the work W.

The laser beam distribution observation device 26 is arranged at a position facing the processing head 40 instead of the work table 16 when observing the laser beam distribution in the liquid jet J.

The laser beam distribution observation device 26 includes an observation device drive mechanism (not shown), and is configured to be movable in the X direction, the Y direction, and the Z direction. As a result, the laser beam distribution observation device 26 can move between the observation position facing the processing head 40 and the retracted position separated from the observation position.

The laser light distribution observation device 26 includes a shielding plate 52, a liquid removing means 54, an imaging lens 56, and a photodetector 58.

The shielding plate 52 is provided on the upper surface (the surface facing the processing head 40) of the laser beam distribution observation device 26. The shielding plate 52 is composed of a light transmitting member (for example, quartz glass) that is optically transparent to the laser light L, shields the liquid jet J, and transmits the laser light L. Therefore, the liquid of the liquid jet J ejected from the liquid jet injection nozzle 48 of the processing head 40 is shielded by the shielding plate 52, while the laser beam L guided by the liquid jet J passes through the shielding plate 52 and the laser. It is incident on the inside of the main body 60 that constitutes the light distribution observation device 26.

The shielding plate 52 is arranged at the same height as the work W held on the work table 16 with respect to the processing head 40. The distance between the processing head 40 and the shielding plate 52 may be equal to the distance between the processing head 40 and the work W. That is, the length of the liquid jet J when the liquid jet J is ejected from the machining head 40 to the work W and the length of the liquid jet J when the liquid jet J is jetted from the machining head 40 to the shielding plate 52 are mutually exclusive. It suffices if they are equal, and it is not always necessary that the work W and the shielding plate 52 have the same height in absolute coordinates. For example, even when the work W and the shielding plate 52 have different heights in absolute coordinates, the heights relative to the processing head 40 may be the same. The distance between the processing head 40 and the shielding plate 52 becomes equal to the distance between the processing head 40 and the work W due to the movement of the head unit 22 (processing head 40) or the laser beam distribution observation device 26 in the Z direction. Is adjusted so that.

The liquid removing means 54 removes the liquid (residual liquid) of the liquid jet J shielded by the shielding plate 52. As the liquid removing means 54, for example, a liquid absorbing means for removing residual liquid by absorption, a liquid suction means for removing residual liquid by suction, a liquid blowing means for removing residual liquid by blowing air, or a combination thereof is appropriately used. Can be adopted. As the liquid absorbing means, it is preferable to adopt a configuration in which a fibrous strip-shaped member such as a cloth is brought into contact with the surface of the shielding plate 52 to absorb the residual liquid into the strip-shaped member by utilizing the capillary phenomenon. it can.

The imaging lens 56 is arranged between the shielding plate 52 and the photodetector 58 inside the main body 60. The imaging lens 56 is composed of a plurality of lenses, and projects the laser light distribution in the liquid jet J onto the light receiving surface of the photodetector 58. That is, the shielding plate 52 and the photodetector 58 are arranged in a positional relationship conjugate with each other with respect to the imaging lens 56, and the laser light distribution in the liquid jet J at the contact surface between the liquid jet J and the shielding plate 52. Is faithfully reproduced on the light receiving surface of the photodetector 58 by the imaging lens 56.

The photodetector 58 receives a projected image showing the laser beam distribution in the liquid jet J imaged by the imaging lens 56. The photodetector 58 has a plurality of light receiving elements arranged two-dimensionally, and each light receiving element outputs an output signal (electric signal) corresponding to the amount of received light as laser light distribution data. As the photodetector 58, for example, a solid-state image sensor such as a CCD image sensor (Charge Coupled Device Image Sensor) or a CMOS image sensor (Complementary Metal Oxide Semiconductor Image Sensor) is preferably used.

Here, the operation when the laser light distribution observation device 26 observes the laser light distribution in the liquid jet J will be described.

First, the laser beam distribution observation device 26 moves to an observation position (a position facing the processing head 40) by an observation device drive mechanism (not shown). The shielding plate 52 is arranged at the same height as the work W held on the work table 16 with respect to the processing head 40.

Next, the pressurized liquid is supplied from the liquid supply means 20 to the processing head 40. The pressurized liquid supplied to the processing head 40 is housed in the liquid chamber 46, and the liquid jet J is further injected from the liquid jet injection nozzle 48 toward the shielding plate 52.

Further, the laser beam L output from the laser oscillator 14 is deflected toward the processing head 40 by the deflection unit 36 via the high-speed deflection means 68 described later, and has a predetermined shape, size, and intensity by the beam shape shaping means 38. It is shaped into a distribution and incident on the condenser lens 42. Further, the laser beam L is focused by the condenser lens 42 on the liquid jet injection nozzle 48 through the window portion 50. As a result, the laser beam L is guided by the liquid jet J, guided by the liquid jet J, and irradiated toward the shielding plate 52.

On the other hand, the liquid jet J ejected from the liquid jet injection nozzle 48 is shielded by the shielding plate 52, and the laser beam L guided by the liquid jet J passes through the shielding plate 52 and is emitted by the imaging lens 56. An image is formed on the light receiving surface of the detector 58. At that time, since the shielding plate 52 and the photodetector 58 are arranged in a positional relationship optically conjugate with each other with respect to the imaging lens 56, the inside of the liquid jet J at the contact surface between the liquid jet J and the shielding plate 52 The laser light distribution of the above is faithfully reproduced on the light receiving surface of the photodetector 58 by the imaging lens 56.

When a projected image showing the laser light distribution in the liquid jet J is formed on the light receiving surface of the photodetector 58 in this way, each light receiving element of the photodetector 58 lasers an output signal according to the amount of light received. It is output to the control unit 30 as light distribution data. The control unit 30 performs various processes on the input laser beam distribution data, and displays an image based on the processed laser beam distribution data on the monitor 64.

As described above, according to the laser beam distribution observation device 26 of the present embodiment, it is possible to observe the laser beam distribution in the liquid jet J on the contact surface between the liquid jet J and the shielding plate 52 (that is, the surface of the work W). It will be possible.

Further, when the laser beam distribution observation device 26 observes the laser beam distribution in the liquid jet J, the liquid (residual liquid) of the liquid jet J shielded by the shielding plate 52 is removed by the liquid removing means 54. Therefore, the distribution of the laser beam in the liquid jet J can be observed stably and accurately without being affected by the scattering of the laser beam L by the residual liquid on the shielding plate 52.

The laser machining apparatus 10 of the present embodiment further includes a high-speed deflection means 68 and a machining shape measuring means 72 in addition to the above-described configuration.

The high-speed deflection means 68 high-speed deflects the laser beam L on the way from the laser oscillator 14 to the processing head 40 (that is, before it enters the liquid jet J). That is, the high-speed deflection means 68 deflects the laser beam L output from the laser oscillator 14 within a predetermined angle range, and switches the deflection angle and the emission direction of the laser beam L at high speed. As the high-speed deflection means 68, for example, an AOD (acoustic-optical deflection element) is preferably used. AOD is to deflect the laser beam L at high speed by changing the frequency of the applied high frequency signal (RF signal). The deflection conditions (deflection angle, deflection direction, and deflection timing) of the high-speed deflection means 68 are controlled by the control unit 30 (an example of the high-speed deflection control means).

It is desirable that the switching speed (frequency) of the high-speed deflection means 68 can be set up to about several MHz. Further, the high-speed deflection means 68 may be used in combination with a means for branching the laser beam L, such as a diffraction optical element.

The processing shape measuring means 72 is arranged at a position adjacent to the processing head 40. The processed shape measuring means 72 is a means for three-dimensionally measuring the processed shape formed on the surface of the work W by the processing head 40. As the processed shape measuring means 72, a non-contact type that measures without contacting the surface of the work W is preferable, and for example, a laser microscope or a white interference microscope can be preferably adopted. The three-dimensional data (machined shape data) of the machined shape measured by the machined shape measuring means 72 is output to the control unit 30.

The control unit 30 includes a CPU, a memory, an input / output circuit unit, various control circuit units, and the like, and controls the operation of each unit of the laser processing apparatus 10. That is, the control unit 30 controls the operations of the laser oscillator 14, the work table moving unit 18, the liquid supply means 20, the head unit 22, the high-speed deflection means 68, the processing shape measuring means 72, and the like.

Although details will be described later, the control unit 30 functions as a high-speed deflection control means for controlling the deflection conditions of the high-speed deflection means 68. Further, the control unit 30 functions as a predictive machining shape calculation means for calculating the predicted machining shape when the work W is machined by the machining head 40 based on the laser beam distribution observed by the laser beam distribution observation device 26. Further, the control unit 30 adjusts the laser beam distribution in the liquid jet J on the surface of the work W based on the comparison between the machined shape of the work W measured by the machined shape measuring means 72 and the target machined shape of the work W. It functions as a laser light distribution adjusting means.

Here, the operating principle of laser processing performed by the laser processing apparatus 10 of the present embodiment will be described. In the following, first, the laser beam distribution in the liquid jet J will be described, and then the effect of laser machining while switching the laser beam distribution in the liquid jet J to a plurality of distributions by the high-speed deflection means 68 will be described. To do.

FIG. 2 is a simplified diagram showing a laser beam path in the liquid jet J when the laser beam L is incident coaxially with the central axis of the liquid jet J. Since the liquid jet J has the same function as the SI type multimode optical fiber, the moving speed of the liquid jet J in the central axis direction (longitudinal direction) actually changes depending on the approach angle to the liquid jet J. , They interfere with each other, and it is considered that they are complicated by speckle noise generated by the minute unevenness of the cylindrical outer peripheral surface (cylindrical surface) of the liquid jet J. Will be described using.

As shown in FIG. 2, when the laser beam L focused by the condenser lens 42 is incident on the central axis of the liquid jet J, the laser beam L repeats expansion and contraction by total internal reflection in the liquid jet J. It is guided along the central axis direction. For example, since the position shown by a in FIG. 2 corresponds to the antinode portion of the laser beam path (the portion where the laser beam L is enlarged), the cross-sectional shape of the laser beam L at that position (the cross-sectional shape perpendicular to the central axis of the liquid jet J). ) Spreads uniformly over the entire liquid jet diameter. On the other hand, at the position shown by b in FIG. 2, since it corresponds to the node portion of the laser beam path (the portion where the laser beam L is reduced), the laser beam L is gathered only in a narrow range at the center of the liquid jet J.

FIG. 3 is a diagram showing the results of actually observing the distribution of the laser beam L at the positions shown in a of FIG. 2 and FIG. 4 at the positions corresponding to the positions shown in b of FIG. Further, FIG. 5 is a diagram showing the depth profile of the machined groove when a linear machined groove is formed in the work W under the same conditions as in FIG. 4 and FIG. 6 is a diagram showing the depth profile of the machined groove when a linear machined groove is formed in the work W.

As can be seen from these figures, the laser beam distribution in the liquid jet J changes depending on the position in the central axis direction of the liquid jet J, that is, the length of the liquid jet J, and further, the laser beam distribution in the liquid jet J. The processed shape also changes according to the change.

Therefore, by controlling the change of the laser light distribution in the liquid jet J on the surface of the work W (laser light irradiation surface), it is possible to obtain a processed shape corresponding to the change in the laser light distribution in the liquid jet J. ..

Next, the effect of laser machining while switching the laser light distribution in the liquid jet J to a plurality of distributions by the high-speed deflection means 68 will be described.

FIG. 7 is an explanatory diagram schematically showing a case where laser processing is performed in a state where the laser light distribution in the liquid jet J is constant. 8 to 10 are explanatory views schematically showing a case where laser processing is performed while switching the laser light distribution in the liquid jet J to a plurality of distributions. On the left side of these figures, the liquid jet J is moved relative to the work W in the machining feed direction (direction along the scheduled cutting line) M to form a linear machining groove K in the work W. The locus of the peak position Q of the laser beam L guided by the liquid jet J (the position where the light intensity of the laser beam L is highest on the surface of the work W) is shown. Further, on the right side of these figures, the depth profile of the machined groove K formed in the work W is shown.

In each figure, for the sake of simplicity, it is assumed that the peak position Q of the laser beam L in the liquid jet J has a uniform intensity. Further, although the peak positions Q of the laser beams L in the liquid jet J are depicted by being sufficiently separated from each other, if it is desired to form a uniform machining groove with respect to the machining feed direction M, the space is 90% or more. It is preferable that the laser processing is performed under overlapping conditions.

As shown in FIG. 7, when laser machining is performed with the laser beam distribution in the liquid jet J constant, the peak position Q of the laser beam L in the liquid jet J is along the machining feed direction M. It will be arranged in a row. Therefore, in the processing groove K, the processing depth at the position corresponding to the peak position Q of the laser beam L in the liquid jet J is deeper than the processing depth at other positions. In such a case, in order to make the machining depth of the machining groove K uniform over the entire width direction, it is necessary to repeat machining a plurality of times in one machining pass, which is a factor that lowers the overall throughput. It becomes.

On the other hand, as shown in FIG. 8, when laser processing is performed while switching the laser distribution in the liquid jet J to a plurality of distributions by the high-speed deflection means 68, the peak position of the laser beam L in the liquid jet J It is possible to change Q in a direction orthogonal to the machining feed direction M (width direction of the machining groove).

In the example shown in FIG. 8, when laser machining is performed while moving the liquid jet J relative to the work W in the machining feed direction M, the peak position Q of the laser beam L in the liquid jet J is machined and fed. Laser machining is performed while sequentially changing the positions at different positions in the direction orthogonal to the direction M at predetermined intervals (pitch) P. In this case, the machining depth of the machining groove K can be made uniform over the entire width direction. Therefore, as compared with the example shown in FIG. 7, a desired processing shape can be obtained without repeating processing in one processing path, and the overall throughput can be improved.

In the example shown in FIG. 8, the peak position Q of the laser beam L in the liquid jet J is from one side (upper side of FIG. 8) in the direction orthogonal to the machining feed direction M (width direction of the machining groove K). It changes sequentially toward the side (lower side of FIG. 8) at a constant interval P, and the peak position Q of the laser beam L in the liquid jet J is the other end in the direction orthogonal to the machining feed direction M (FIG. 8). When the peak position Q of the laser beam L in the liquid jet J is reached, the peak position Q of the laser beam L is switched to one end in the direction orthogonal to the machining feed direction M, and then the liquid jets are jetted in the same order. The peak position Q of the laser beam L in J changes sequentially.

On the other hand, in the example shown in FIG. 9, the peak position Q of the laser beam L in the liquid jet J is from one side (upper side of FIG. 9) to the other side (lower side of FIG. 9) in the direction orthogonal to the processing feed direction M. When the peak position Q of the laser beam L in the liquid jet J reaches the other end in the direction orthogonal to the machining feed direction M, the liquid jet changes sequentially toward the side) at regular intervals P. The peak position Q of the laser beam L in J changes sequentially from the other side in the direction orthogonal to the machining feed direction M toward one side at a constant interval P, and then the laser beam in the liquid jet J in the same order. The peak position Q of L changes sequentially. According to the example shown in FIG. 9, since the distance P between the peak positions Q of the laser beams L adjacent to each other in the direction orthogonal to the machining feed direction M is always constant, the laser is compared with the example shown in FIG. The switching mark of the peak position Q of the light L is less likely to appear, and the processing quality in laser processing can be further improved.

The example shown in FIG. 10 is a case where the number of peak positions Q of the laser beam L at both ends in the direction orthogonal to the machining feed direction M is distributed more than in the example shown in FIG. In this case, the machining depth at both ends of the machining groove K in the width direction can be deeper than that at the central portion. Although not shown, when the number of peak positions Q of the laser beam L in the central portion in the direction orthogonal to the machining feed direction M is distributed a large number, the machining depth in the central portion in the width direction of the machining groove K Can be processed deeper than both ends.

As described above, in the laser processing apparatus 10 of the present embodiment, the laser light L is high-speed deflected by the high-speed deflection means 68, so that the laser light distribution in the liquid jet J on the surface of the work W is switched to a plurality of distributions for laser processing. It can be performed. As a result, the laser beam distribution in the liquid jet J can be actively controlled, and an arbitrary processing shape (target processing shape) can be obtained without repeating processing in one processing path.

At this time, the control unit 30 functioning as the high-speed deflection control means is a high-speed deflection means so that the peak position Q of the laser beam L in the laser distribution in the liquid jet J is scanned in the direction orthogonal to the machining feed direction. Control is performed to change the deflection conditions (deflection angle, deflection direction, and deflection timing) of 68.

11 to 13 are diagrams for explaining the processing result when laser processing is performed while switching the laser light distribution in the liquid jet J to two distributions by the high-speed deflection means 68. Here, the result when the single mode laser beam L is used is shown.

FIG. 11 is a diagram showing the results of observing the two laser beam distributions to be switched by the high-speed deflection means 68 by the laser beam distribution observing device 26. Further, FIG. 12 shows projection data obtained by projecting the two laser beam distributions shown in FIG. 11 in directions orthogonal to the processing feed direction (horizontal direction in FIG. 11). Note that (a) and (b) in each figure correspond to each other.

FIG. 13 shows the processing obtained when a linear processing groove was formed while alternately switching the two laser beam distributions shown in FIGS. 11 and 12 at the same ratio (1: 1 usage ratio in this example). It shows the depth profile of the groove. Here, laser machining was performed while switching the two laser beam distributions at 15 kHz by the high-speed deflection means 68 and conveying the moving speed (machining feed rate) of the work W in the machining feed direction (X direction) at 30 mm / s. The result of the time is shown. This corresponds to switching the laser beam distribution in the liquid jet J every time the machining distance (movement distance of the work W in the machining feed direction) advances by 2 μm, and as shown in FIG. 13, the machining groove The processing depth of is an averaged shape over the entire processing width in the width direction.

When the switching speed of the laser beam distribution in the liquid jet J is slow, the peak position Q of the laser beam L in the liquid jet J changes with the switching of the laser beam distribution in the liquid jet J with respect to the processing feed direction. A switching mark appears when the laser is used, and an uneven shape is formed in the machined groove. For example, when switching between two laser light distributions alternately, if laser processing is performed under the condition that the processing feed speed is 50 mm / s and the switching speed of the two laser light distributions is 500 Hz, one laser beam is used. Since the machining distance per distribution is 100 μm (that is, the laser beam distribution is switched every time the machining distance advances by 100 μm), irregularities are formed every 100 μm in the machining feed direction (longitudinal direction of the machining groove).

On the other hand, when laser machining is performed under the condition that the machining feed rate is 50 mm / s and the switching speed of the two laser light distributions is 50 kHz, the continuous machining distance is 1 μm and the unevenness of the machining groove is It becomes impossible to distinguish.

Next, a laser processing method using the laser processing apparatus 10 according to the present embodiment will be described with reference to FIG. FIG. 14 is a flowchart showing an example of a laser processing method using the laser processing apparatus 10 according to the present embodiment. Unless otherwise specified, each process is executed under the control of the control unit 30.

(Step S10: Target machining shape setting process)
First, when one machining shape is selected by the user from a plurality of machining shapes registered in advance in the laser machining apparatus 10, the control unit 30 sets the selected machining shape as the target machining shape. Instead of the user's selection, the laser machining apparatus 10 may automatically set a predetermined default shape as the target machining shape. As shown in FIG. 15, the laser processing apparatus 10 has a plurality of processing shapes (K1 to K3), a plurality of laser light distributions (PT1 to PT9) corresponding to each processing shape, and each laser. A reference table (look-up table) showing the correspondence between the usage ratio of the light distribution and the deflection patterns (C1 to C9) of the high-speed deflection means 68 corresponding to each laser light distribution is stored in the memory (not shown). ing. Further, a plurality of laser light distributions (for example, laser light distributions PT1 and PT2) corresponding to the same processed shape can be realized by changing the deflection pattern (deflection angle and deflection direction) of the high-speed deflection means 68. To do.

(Step S12: Laser light distribution setting step)
Next, the control unit 30 controls the processing conditions of each unit of the apparatus (for example, the mirror of the deflection unit 36) so that the laser beam distribution corresponding to the target processing shape set in the target processing shape setting step (step S10) is realized. Set the angle, etc.). It is assumed that the laser machining apparatus 10 stores in advance the machining conditions of each part of the apparatus corresponding to each machining shape as internal values in a memory (not shown).

(Step S14: Laser light distribution acquisition step)
Next, the laser light distribution observation device 26 observes the laser light distribution in the liquid jet J. At this time, if the laser beam distribution observation device 26 is not at the observation position of the laser beam distribution (position facing the processing head 40), the laser beam distribution observation device 26 is moved to the observation position by an observation device drive mechanism (not shown). When observing the laser light distribution, if the intensity of the laser light L emitted from the processing head 40 toward the laser light distribution observation device 26 exceeds the observable range of the laser light distribution observation device 26, the beam The shape shaping means 38 is used to adjust the intensity of the laser beam L so as to be low. The laser beam distribution data indicating the laser beam distribution in the liquid jet J observed by the laser beam distribution observation device 26 is output to the control unit 30. The laser beam distribution observation device 26 observes the laser beam distribution in the liquid jet J for all the laser beam distributions corresponding to the target processed shape.

(Step S16: Expected processing shape calculation process)
Next, the control unit 30 functions as a predictive machining shape calculation means, and predicts when the work W is machined by the machining head 40 based on the laser beam distribution observed in the laser beam distribution acquisition step (step S14). Calculate the processed shape. Specifically, the laser beam distribution data indicating each laser beam distribution observed by the laser beam distribution observation device 26 is converted into projection data projected in a direction orthogonal to the processing feed direction. Then, the expected processing shape is calculated by adding the data obtained by multiplying the projection data of each laser light distribution by the usage ratio of each laser light distribution (see FIG. 15). The predicted machining shape calculated by the control unit 30 is displayed on the monitor 64. As a result, the user can easily grasp the expected machining shape after machining.

Here, a method of calculating the expected processing shape will be described with reference to FIGS. 16 to 23.

16 and 17 are views showing a first example of a method for calculating a predicted processed shape.

The two laser beam distributions 100A and 100B shown in FIGS. 16A and 16B are graphs showing projection data projected in a direction orthogonal to the processing feed direction, and the horizontal axis is the laser beam L. Is the distribution width (direction orthogonal to the processing feed direction), and the vertical axis is the distribution intensity of the laser beam L (laser beam intensity).

In the laser beam distribution 100A shown in FIG. 16 (a), the peak position of the laser beam L is biased to one side (left side in the figure) of the distribution width, whereas the laser beam shown in FIG. 16 (b) is biased. In the distribution 100B, the peak position of the laser beam L is biased to the other side (right side in the figure) of the distribution width. Further, the peak intensities of the two laser beam distributions 100A and 100B are the same.

Using such laser light distributions 100A and 100B, the calculation result of the expected processing shape 200A when laser processing is performed while switching the laser light distributions 100A and 100B at a usage ratio of 1: 1 in one processing path. It is shown in FIG. The predicted processing shape 200A shown in FIG. 17 is obtained by adding data obtained by multiplying each of the two laser beam distributions 100A and 100B shown in FIGS. 16A and 16 by a 1: 1 usage ratio. Can be obtained by

18 to 20 are views showing a second example of a method for calculating the expected processed shape.

The two laser beam distributions 100C and 100D shown in FIGS. 18A and 18 have the same biased shapes as the two laser beam distributions 100A and 100B shown in FIGS. 16A and 16B. However, the difference is that the peak intensity ratio is 1: 2.

Using such laser light distributions 100C and 100D, the calculation result of the expected processing shape 200B when laser processing is performed while switching the laser light distributions 100C and 100D at a usage ratio of 1: 1 in one processing path. It is shown in FIG. In this case, since the peak intensities of the two laser beam distributions 100C and 100D are different, when the usage ratio is 1: 1, as shown in FIG. 19, the expected processing shape 200B has the bottom surface of the processing groove. It is not uniform in the width direction (horizontal direction in the figure).

Further, FIG. 20 shows the calculation result of the expected processing shape 200C when the laser processing is performed while switching the laser light distributions 100C and 100D at a usage ratio of 2: 1 in one processing path. When the peak intensities of the two laser beam distributions 100C and 100D are different, the predicted processing shape 200C shown in FIG. 20 is predicted as shown in FIG. 19 by increasing the usage ratio of the laser beam distribution 100C having the lower peak intensity. Compared with the machined shape 200B, the bottom surface of the machined groove can be made uniform over the width direction.

21 to 23 are views showing a third example of a method for calculating the expected processed shape.

The three laser beam distributions 100E, 100F, and 100G shown in FIGS. 21 (a) to 21 (c) have laser beams L on one side (left side of the figure), the center, and the other side (right side of the figure) of the distribution width, respectively. The peak position of is biased. Further, the peak intensities of the three laser beam distributions 100E, 100F, and 100G are the same.

Expected processing when laser processing is performed while switching the laser light distributions 100E, 100F, 100G at a usage ratio of 1: 1: 1 in one processing path using such laser light distributions 100E, 100F, 100G. The calculation result of the shape 200D is shown in FIG. As described above, the predicted processed shape 200D shown in FIG. 22 can be obtained by adding data obtained by multiplying each of the three laser beam distributions 100E, 100F, and 100G by a usage ratio of 1: 1: 1. Can be done.

Further, the expected processing shape 200E when laser processing is performed while switching the laser light distributions 100E, 100F, 100G with the usage ratio of the laser light distributions 100E, 100F, 100G set to 2: 1: 2 in one processing path. The calculation result is shown in FIG. When the peak intensities of the three laser beam distributions 100E, 100F, and 100G are different, the expected processing shape 200E shown in FIG. 23 is obtained by reducing the usage ratio of the central laser beam distribution 100F, which increases the integration ratio. Compared with the expected processing shape 200D shown in the above, the bottom surface of the processing groove can be made uniform over the width direction.

As described above, even when the peak intensities of the plurality of laser light distributions are different, an arbitrary processed shape can be obtained by adjusting the usage ratio thereof.

Further, when laser processing is performed while switching three or more laser light distributions in one processing path, finer processing shape can be adjusted by distributing each of them at an arbitrary ratio.

Here, for the sake of simplicity, the addition of the laser beam distributions is directly reflected in the processing shape, but in general, the processing rate (R) is proportional to the irradiation fluence (F). Instead, it is known to be expressed by the following equation.

R = C ₁ x ln (F / C ₂ )
Note that ln indicates the natural logarithm, and C ₁ and C ₂ indicate constants.

FIG. 24 is a log-log graph showing an example of the correspondence between the irradiation fluence and the processing rate. The horizontal axis represents the logarithm of the irradiation fluence, and the vertical axis represents the logarithm of the processing rate. Here, it should be noted that, as can be seen from FIG. 24, each work material has a threshold value for irradiation fluence. If a part of the laser light distribution (light intensity distribution) is an irradiation fluence below the threshold value, that part loses its contribution to machining, and there is a difference from the calculation result of the expected machining shape by simple addition. It is necessary to pay attention to.

(Step S18: Judgment step)
Next, the control unit 30 compares the predicted machining shape calculated in the predicted machining shape calculation step (step S16) with the target machining shape to calculate an error, and determines that the error is within a preset allowable error range. If it is determined, the process proceeds to the next step S20. On the other hand, if it is determined that the error is not within the permissible error range, the process proceeds to step S26.

(Step S20: Test processing process)
Next, using the test machining work, the test machining work is tested under the machining conditions when the error indicating the difference between the two shapes is determined to be within the margin of error in the determination step (step S18). Perform processing.

(Step S22: Machining shape measurement step)
Next, the machined shape measuring means 72 measures the machined shape of the machined groove formed in the test machining work. At this time, if there is no test machining work at the measurement position of the machining shape measuring means 72 (the position facing the machining shape measuring means 72), the work table 16 holding the test machining work is moved to the measurement position. The processed shape data (three-dimensional shape data) indicating the processed shape measured by the processed shape measuring means 72 is output to the control unit 30.

(Step S24: Machining shape comparison process)
Next, the control unit 30 compares the machining shape data obtained in the machining shape measurement step (step S22) with the target machining shape data, calculates an error, and the error is within a preset allowable error range. If it is determined, the process proceeds to step S28. On the other hand, if it is determined that the error is not within the permissible error range, the process proceeds to step S26.

(Step S26: Laser beam distribution adjustment step)
In the determination step (step S18), when it is determined that the error indicating the difference between the expected machining shape calculated in the prediction machining shape calculation step (step S16) and the target machining shape is not within the permissible error range, or the machining shape. In the comparison step (step S24), when it is determined that the error indicating the difference between the machining shape data obtained in the machining shape measurement step (step S22) and the target machining shape data is not within the permissible error range, the control unit Reference numeral 30 denotes a laser light distribution adjusting means, which adjusts the laser light distribution in the liquid jet J so that the error is small. After that, the process returns to step S12, and the processing conditions of each part of the apparatus are set (changed) so that the adjusted laser beam distribution is realized, and the same process is repeated. In the laser light distribution adjusting step, when there are a plurality of laser light distributions corresponding to the target processing shape, it is also included to change the usage ratio of each laser light distribution.

(Step S28: Main processing step)
When it is determined in the machining shape comparison step (step S24) that the error indicating the difference between the machining shape data obtained in the machining shape measurement step (step S22) and the target machining shape data is within the permissible error range. , The control unit 30 carries out the main processing step under the processing conditions adjusted so far. When this processing step is performed, the laser beam distribution observation device 26 moves to the retracted position.

In this machining step, the control unit 30 moves the work W sucked and held on the holding surface 16a of the work table 16 and the machining head 40 relatively in the machining feed direction (X direction) (an example of the moving step). The liquid jet J is ejected from the liquid jet injection nozzle 48 of the processing head 40 toward the work W, and the laser beam L guided by the liquid jet J is irradiated to the work W (an example of the laser beam irradiation process). .. As a result, a machined groove having a predetermined depth is formed in the work W along the planned division line without causing peeling of the film, burrs, or the like.

Further, at this time, the control unit 30 performs laser processing while switching the laser beam distribution in the liquid jet J to a plurality of distributions by deflecting the laser beam L at high speed by the high-speed deflection means 68 (high-speed deflection step and high-speed). An example of a deflection control process). As a result, the target machining shape can be obtained without repeating machining in one machining pass.

When the formation of the machined groove of one line is completed, the Y table to which the head unit 22 is attached is indexed in the Y direction, and the machined groove is formed in the same manner on the next line.

When the machined grooves are formed along all the planned cutting lines parallel to the X direction, the θ rotary table 34 is rotated by 90 °, and all the machined grooves are formed in the same manner for the lines orthogonal to the previous line.

As described above, according to the present embodiment, by high-speed deflection of the laser beam L by the high-speed deflection means 68, laser processing is performed while switching the laser beam distribution in the liquid jet J on the surface of the work W to a plurality of distributions. be able to. As a result, the laser beam distribution in the liquid jet J can be actively controlled, and the target machining shape can be obtained without repeating machining in one machining path.

Further, in the present embodiment, the surface of the work W is such that the machining shape measured by the machining shape measuring means 72 (the machining shape actually machined by the laser beam emitted from the machining head 40) approaches the target machining shape. Feedback control is performed to automatically adjust the laser beam distribution in the liquid jet J in the above. Therefore, in order to obtain the target machined shape, it is not necessary to manually repeat the adjustment of the laser beam distribution and the evaluation of the machined shape for several cycles. By shortening the time, it is possible to reduce the work man-hours and improve the production efficiency, and it is possible to obtain the target machining shape with high accuracy.

Further, in the present embodiment, the expected machining shape when the work W is machined by the machining head 40 can be calculated based on the laser beam distribution observed by the laser beam distribution observing device 26, so that the expected machining shape after machining can be calculated. The expected machining shape can be easily grasped. Further, since feedback control is performed to adjust the laser beam distribution in the liquid jet J on the surface of the work W so that the expected machining shape approaches the target machining shape, the target machining shape can be efficiently obtained in a short time. It becomes.

In the present embodiment, when a pulse laser is used as the laser beam L, it is preferable that the repetition frequency of the pulse laser is sufficiently faster than the switching speed (frequency) of the high-speed deflection means 68.

Further, in the present embodiment, the angle range in which the high-speed deflection means 68 deflects the laser beam L at high speed is set within the angle range in which the liquid jet J can be incident (the liquid jet incident angle range). Not limited to this, it may be set wider than the liquid jet incident angle range. In this case, when the laser beam L is high-speed deflected by the high-speed deflection means 68, not only the pattern in which the laser beam L is incident in the liquid jet J (laser beam distribution) but also the pattern in which the laser beam L is not incident in the liquid jet J (Laser beam distribution) can also be included. As a result, it is possible to reduce the substantial intensity of the laser beam L applied to the work W, so that the processed shape can be controlled in a wider range and finely, and the processed shape remains the same as the processed shape of the structure. It is possible to control the machining rate itself depending on the presence or absence.

Further, in the present embodiment, the case where the laser machining is performed while switching the laser beam distribution in the liquid jet J to a plurality of distributions in one machining pass has been described, but the laser beam distribution is not switched in one machining pass. It may include the case where the laser processing is performed with the laser light distribution constant.

FIG. 25 describes a laser processing method in a case where laser processing is performed in a state where the laser light distribution in the liquid jet J is constant in one processing path (that is, when one type of laser light distribution is used). It is a conceptual diagram for. Hereinafter, description will be made with reference to FIG. 25.

First, as shown in FIG. 25 (a), when one machining shape is selected by the user from a plurality of machining shapes (machining grooves) preset in the laser machining apparatus 10, the control unit 30 receives the control unit 30. The selected machining shape is set as the target machining shape. Here, it is assumed that the machining shape indicating the rectangular machining groove, which is the portion surrounded by the broken line in the figure, is selected and set as the target machining shape.

Next, as shown in FIGS. 25 (b) and 25 (c), the control unit 30 sets the processing conditions of each part of the apparatus so that the laser light distribution (target laser light distribution) corresponding to the target processing shape is realized. To set. Note that FIG. 25B shows projection data in which the target laser beam distribution is projected in a direction orthogonal to the processing feed direction. Further, FIG. 25 (c) is a plan view of the target laser beam distribution, the horizontal axis represents the position in the direction orthogonal to the machining feed direction, and the vertical axis represents the position in the machining feed direction. Further, in FIG. 25 (b), the high density portion (dark portion) in the figure corresponds to the high laser light intensity portion, and the low density portion (bright portion) in the figure corresponds to the low laser light intensity portion. Corresponds to. The same applies to (g) of FIG. 25, which will be described later.

Next, the laser light distribution observation device 26 observes the laser light distribution in the liquid jet J. FIG. 25 (d) shows the projection data (actual measurement value) of the laser light distribution observed by the laser light distribution observation device 26. The broken line in the figure is the projection data (target value) of the target laser light distribution shown in FIG. 25 (b).

Next, the control unit 30 compares the laser light distribution observed by the laser light distribution observation device 26 with the target laser light distribution to calculate an error, and whether or not the error is within a preset allowable error range. Is determined. When it is determined that the error is not within the permissible error range, control is performed so that the error becomes small (that is, the laser beam distribution observed by the laser beam distribution observation device 26 approaches the target laser beam distribution). After adjusting the laser beam distribution, the unit 30 repeats the same process until the error is determined to be within the permissible range.

On the other hand, as shown in FIG. 25 (d), the laser beam distribution observed by the laser beam distribution observation device 26 is close to the target laser beam distribution, and the error due to the comparison between the two is within the permissible error range. If it is determined, the test machining workpiece is subjected to test machining under the machining conditions at the time of the judgment.

Next, the machining shape (machining groove) formed on the test machining work is measured by the machining shape measuring means 72. FIG. 25 (e) shows an example of the measurement result of the processed shape measured by the processed shape measuring means 72. The solid line in the figure indicates the processed shape (measured value) measured by the processed shape measuring means 72, and the broken line in the figure indicates the target processed shape (measured value).

Next, the control unit 30 compares the machining shape measured by the machining shape measuring means 72 with the target machining shape, calculates an error, and determines whether or not the error is within a preset allowable error range. To do. If it is determined that the error is within the permissible error range, this processing step is performed under the processing conditions at the time of the determination.

On the other hand, as shown in FIG. 25 (e), the error between the processed shape measured by the processed shape measuring means 72 and the target processed shape are not close to each other, and the error obtained by comparing the two is not within the permissible error range. When it is determined, the control unit 30 sets the position where the error is larger as the error is smaller based on the result of comparing the machined shape measured by the machined shape measuring means 72 and the target machined shape. The target laser light distribution is adjusted so that the laser light intensity is relatively large. An example of the adjusted target laser beam distribution is shown in FIGS. 25 (f) and 25 (g). In the case shown in FIG. 25 (e), the error at the position on the right side in the figure is relatively large as compared with the position on the left side in the figure. Therefore, as shown in FIGS. The target laser light distribution is adjusted so that the laser light intensity at the position on the right side of the center is relatively large.

After adjusting the target laser beam distribution in this way, the control unit 30 repeats the same process until it is determined that the error between the processed shape measured by the processed shape measuring means 72 and the target processed shape is within the allowable range. Do.

That is, as shown in FIG. 25 (h), adjustment was performed until the laser beam distribution (measured value) observed by the laser beam distribution observation device 26 approaches the corrected target laser beam distribution (target value). After that, further test machining is performed, and as shown in FIG. 25 (i), adjustment is performed until the machining shape (measured value) measured by the machining shape measuring means 72 approaches the target machining shape (measured value). .. Then, when it is determined that the error between the processed shape measured by the processed shape measuring means 72 and the target processed shape is within the permissible error range, the main processing step is performed under the processing conditions at the time of the determination. carry out.

As described above, even when laser machining is performed with the laser beam distribution in the liquid jet J constant in one machining path, the machining shape measured by the machining shape measuring means 72 is brought closer to the target machining shape. , Feedback control is performed to automatically adjust the laser beam distribution in the liquid jet J on the surface of the work W. Therefore, in order to obtain the target machined shape, it is not necessary to manually repeat the adjustment of the laser beam distribution and the evaluation of the machined shape for several cycles. By shortening the time, it is possible to reduce the work man-hours and improve the production efficiency, and it is possible to obtain the target machining shape with high accuracy.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. Hereinafter, the parts common to the first embodiment will be omitted, and the characteristic parts of the present embodiment will be mainly described.

FIG. 26 is a schematic view showing the configuration of the laser processing apparatus 10A according to the second embodiment. In FIG. 26, components common to or similar to those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 26, the laser processing apparatus 10A according to the second embodiment is provided with a reflection mirror 37 and a spatial optical phase modulator 70 between the laser oscillator 14 and the high-speed deflection means 68. It is different from the first embodiment.

The reflection mirror 37 reflects the laser beam L output from the laser oscillator 14 toward the spatial optical phase modulator 70.

The spatial optical phase modulator 70 is a means for adjusting (modulating) the phase of the laser beam L incident from the laser oscillator 14 via the reflection mirror 37, and its operation is controlled by the control unit 30. As the spatial light phase modulator 70, for example, LCOS-SLM (Liquid Crystal on Silicon-Spatial Light Modulator) or the like can be preferably adopted. The laser beam L whose phase has been adjusted by the spatial optical phase modulator 70 is incident on the high-speed deflection means 68. Since the configuration and operation of the spatial optical phase modulator 70 are known, specific description thereof will be omitted here.

FIG. 27 is a diagram for explaining the effect of phase adjustment by the spatial optical phase modulator 70. FIG. 27 shows how the laser beam L condensed by the condenser lens 42 is incident on the liquid jet J, and (a) shows the case where the spatial optical phase modulator 70 is not provided (no phase adjustment). b) shows the case where the spatial optical phase modulator 70 is provided (with phase adjustment).

As shown in FIG. 27 (a), when the condensing lens 42 condenses the laser beam L so as to be incident on the liquid jet J, aberration may occur in the laser beam L. On the other hand, in the present embodiment, as shown in FIG. 27 (b), the phase of the laser beam L is adjusted by the spatial optical phase modulator 70, so that the laser beam L at the time of incidence on the liquid jet J is generated. It is possible to correct the aberration. As a result, the laser beam distribution in the liquid jet J at the processing position (surface of the work W) can be adjusted with high accuracy.

As described above, according to the laser processing apparatus 10A according to the second embodiment, the laser light distribution in the liquid jet J is adjusted by adjusting the phase of the laser light L by the space light phase modulator 70, and the processed shape is formed. Can be adjusted in more detail.

It is also possible to branch the laser beam L into a plurality of laser beams by adjusting the phase of the laser beam L with the spatial optical phase modulator 70. As a result, it is possible to switch the pattern (laser beam distribution) in which the laser beam L is branched into a plurality of laser beams, and it is possible to form an arbitrary processed shape in detail and efficiently.

(Third Embodiment)
Next, a third embodiment of the present invention will be described. Hereinafter, the parts common to each of the above-described embodiments will be omitted, and the characteristic parts of the present embodiment will be mainly described.

FIG. 28 is a schematic view showing the configuration of the laser processing apparatus 10B according to the third embodiment. In FIG. 28, components common to or similar to those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 28, the laser machining apparatus 10B according to the third embodiment is different from the first embodiment in that the work surface state measuring means 74 is provided at a position adjacent to the machining head 40. ..

The work surface condition measuring means 74 is a means for measuring the surface condition of the work W. As the work surface state measuring means 74, a non-contact type that measures without contacting the surface of the work W is preferable, and for example, a spectroscopic interference laser displacement meter, a sensor using a knife edge method, a camera, or the like is adopted. Can be done. The work surface condition measuring means 74 may be any as long as it can measure the surface condition of the work W (for example, the height of the surface of the work W, the reflection intensity, etc.). Further, the work surface state measuring means 74 is not limited to the non-contact type that measures without contacting the surface of the work W, and measures the state of the surface of the work W by contacting the surface of the work W. You may.

According to such a configuration, the position of the structure (for example, a metal pad) on the planned cutting line on the surface of the work W can be detected by measuring the state of the surface of the work W by the work surface state measuring means 74. it can. The position of the structure on the scheduled cutting line detected in this way is stored in the memory unit (not shown). As a result, when laser machining is performed, it is possible to change the machining conditions depending on the presence or absence of a structure on the planned cutting line. That is, cutting is performed by performing laser processing while switching the laser beam distribution in the liquid jet J to a plurality of distributions so that the intensity of the laser beam L is higher in the portion with the structure than in the portion without the structure. Even when the structure exists on the scheduled line (that is, when the machining rate is not uniform on the same scheduled cutting line), the machining depth can be made uniform (uniform depth in the width direction). Become. That is, by changing the actual intensity of the laser beam L applied to the work W according to the position of the structure measured by the work surface state measuring means 74, the processing rate of the entire processing shape such as the processing groove can be adjusted. It is possible to keep it uniform.

29 and 30 are views for explaining the effect of the third embodiment, and when the machining groove K is formed in the work W along the planned cutting line, depending on the presence or absence of a structure on the planned cutting line. An example of the relationship between the amount of irradiation light (laser light intensity), the processing rate, and the processing depth when different materials (hardness) are present is shown. Here, it is assumed that the work material G1 has a higher hardness than the work material G2. Further, as shown in FIG. 8, the case where the laser machining is performed while sequentially changing the peak position Q of the laser beam L in the liquid jet J in the direction orthogonal to the machining feed direction M is shown. The hardness here means the difficulty of processing with respect to the processing conditions used (wavelength of laser beam L, etc.).

FIG. 29 shows a case where the processing conditions are constant regardless of the presence or absence of the structure on the planned cutting line. As shown in FIGS. 29 (a) and 29 (b), when the irradiation light amount of the laser beam L irradiated on the surface of the work W is constant along the processing feed direction M, it is shown in FIG. 29 (c). As described above, the machining rate changes depending on the difference between the work material G1 and the work material G2. Therefore, as shown in FIG. 29 (d), the machining depth in the machining groove K is different between the work material G1 and the work material G2, and the machining depth is non-uniform as a whole.

FIG. 30 shows a case where the processing conditions are changed depending on the presence or absence of the structure on the planned cutting line. As shown in FIGS. 30A and 30B, when the distance between the peak positions Q of the laser beam L in the liquid jet J in the machining feed direction is larger in the work material G2 than in the work material G1. The amount of irradiation light of the laser beam L irradiated on the surface of the work W is smaller in the work material G2 than in the work material G1. In this case, as shown in FIG. 30 (c), the machining rate of the work material G2 is higher than that of the work material G1. Therefore, as shown in FIG. 30D, the machining depth in the machining groove K is the same for the work material G1 and the work material G2, and the machining depth is uniform as a whole. The amount of laser light L irradiated on the surface of the work W is preferably adjusted according to the surface condition of the work W measured by the work surface condition measuring means 74.

As described above, according to the laser processing apparatus 10B according to the third embodiment, the actual intensity of the laser beam L applied to the work W is determined according to the position of the structure measured by the work surface state measuring means 74. By changing it, it is possible to obtain a desired processed shape.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above examples, and it goes without saying that various improvements and modifications may be made without departing from the gist of the present invention. ..

10 ... Laser processing device, 12 ... Laser power supply, 14 ... Laser oscillator, 16 ... Work table, 16a ... Holding surface, 18 ... Work table moving part, 20 ... Liquid supply means, 22 ... Head unit, 26 ... Laser light distribution observation Device, 30 ... Control unit, 32 ... X table, 34 ... θ rotation table, 36 ... Deflection unit, 37 ... Reflection mirror, 38 ... Beam shape shaping means, 40 ... Processing head, 42 ... Condensing lens, 44 ... Head body , 46 ... Liquid chamber, 48 ... Liquid jet injection nozzle, 50 ... Window, 52 ... Shielding plate, 54 ... Liquid removing means, 56 ... Imaging lens, 58 ... Light detector, 60 ... Main body, 64 ... Monitor, 68 ... High-speed deflection means, 70 ... Spatial optical phase modulator, 72 ... Machining shape measuring means, 74 ... Work surface condition measuring means, L ... Laser light, J ... Liquid jet

Claims (10)

Laser oscillator and
A processing head that irradiates the workpiece while guiding the laser light output from the laser oscillator with a liquid jet.
A moving means for relatively moving the processing head and the work piece,
A laser light distribution observing means for observing the laser light distribution in the liquid jet on the laser light irradiation surface of the work piece,
Based on the laser beam distribution observed by the laser beam distribution observing means, the predicted machining shape calculating means for calculating the predicted machining shape when the workpiece is machined by the machining head, and the predicted machining shape calculating means.
A high-speed deflection means that deflects the laser beam at high speed on the way from the laser oscillator to the processing head.
By changing the deflection conditions of the high-speed deflection means when irradiating the workpiece with the laser beam from the machining head while relatively moving the machining head and the workpiece by the moving means. , A high-speed deflection control means for switching the laser beam distribution into a plurality of distributions,
With
The expected processing shape calculation means is based on the plurality of distributions of the laser light observed by the laser light distribution observing means, and the processing head switches the laser light distribution to the plurality of distributions by the high-speed deflection control means. Calculate the expected processing shape when the work piece is processed.
Laser processing equipment equipped with. A low-speed deflection means for deflecting the laser beam output from the laser oscillator toward the processing head is provided.
The high-speed deflection means performs higher-speed deflection and a narrower range of deflection than the low-speed deflection means.
The laser processing apparatus according to claim 1. The high-speed deflection means is an acoustic-optical deflection element.
The laser processing apparatus according to claim 1 or 2. The high-speed deflection control means of the high-speed deflection control means so that the peak position of the laser beam in the laser light distribution is scanned in a direction orthogonal to the relative moving direction of the processing head and the workpiece. Change the deflection condition,
The laser processing apparatus according to any one of claims 1 to 3. The laser beam distribution adjusting means for adjusting the laser beam distribution is provided based on the comparison between the predicted machining shape calculated by the predictive machining shape calculation means and the target machining shape of the workpiece.
The laser processing apparatus according to any one of claims 1 to 4. A machining shape measuring means for measuring the machining shape formed by the machining head is provided.
The laser light distribution adjusting means adjusts the laser light distribution based on the comparison between the processed shape measured by the processed shape measuring means and the target processed shape of the workpiece.
The laser processing apparatus according to claim 5. A laser beam irradiation process that irradiates a work piece with a laser beam induced by a liquid jet,
A moving step of relatively moving the liquid jet and the work piece,
A laser light distribution observation step for observing the laser light distribution in the liquid jet on the laser light irradiation surface of the work piece,
Based on the laser beam distribution observed in the laser beam distribution observation step, the expected machining shape calculation step of calculating the expected machining shape when the workpiece is machined by the laser beam, and the prediction machining shape calculation step.
A high-speed deflection step that deflects the laser beam at high speed and
When the laser beam is irradiated to the workpiece by the laser beam irradiation step while the liquid jet and the workpiece are relatively moved by the moving step, the laser beam is transmitted at high speed in the high-speed deflection step. A high-speed deflection control step that switches the laser beam distribution to a plurality of distributions by changing the deflection conditions at the time of deflection, and
With
The predicted processing shape calculation step is based on the plurality of distributions of the laser light observed in the laser light distribution observation step, and the laser light irradiation is performed while switching the laser light distribution to the plurality of distributions by the high-speed deflection control step. Calculate the expected processing shape when the work piece is processed by the process.
Laser processing method including. A low-speed deflection step of deflecting the laser beam toward the liquid jet is provided.
The high-speed deflection step performs higher-speed deflection and a narrower range of deflection than the low-speed deflection step.
The laser processing method according to claim 7. In the high-speed deflection step, high-speed deflection of the laser beam is performed using an acoustic-optical deflection element.
The laser processing method according to claim 7 or 8. The high-speed deflection control step is performed in the high-speed deflection control step so that the peak position of the laser beam in the laser beam distribution is scanned in a direction orthogonal to the relative moving direction of the liquid jet and the workpiece. Changing the deflection conditions,
The laser processing method according to any one of claims 7 to 9.

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