JP7190643B2 - LASER PROCESSING APPARATUS AND LASER PROCESSING METHOD - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laser processing apparatus and a laser processing method, and more particularly to a technique for processing a workpiece with a laser beam guided by a liquid jet.

In recent years, with the high 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 are used on 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 insulating 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 is likely to cause film peeling, burrs, and the like, which poses a serious problem in the dicing process. In particular, when the device layer includes a Low-k film, the Low-k film is very fragile, and therefore, when cut with a dicing blade, the Low-k film tends to peel off. That is, cutting with a dicing blade destroys the Low-k film, and if the destroyed region spreads over the device formation region (chip formation region), the chip becomes a defective product, which reduces the yield of the manufactured semiconductor device. It becomes a factor that leads to

In order to solve the above problem, prior to cutting with a dicing blade, a technique is disclosed in which laser processing grooves are formed along division lines called streets to divide the device layer, and then cutting is performed with a dicing blade. (See Patent Document 1, for example).

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 process, in order to form a laser-processed groove wider than the width of the dicing blade, laser light irradiation must be performed by reciprocating along one street. Therefore, there is a problem that the productivity is poor and the cost is increased.

On the other hand, Patent Literature 2 discloses a laser processing apparatus that injects a pressurized liquid as a liquid jet and uses it as an optical waveguide to irradiate a laser beam onto a workpiece. In this laser processing device, a liquid jet is sprayed toward the workpiece, so the laser light is guided toward the workpiece without being diffused by the liquid jet, while preventing the effects of heat damage and contamination during processing. Therefore, high-precision machining can be performed. In addition, dicing processes such as dicing with a dicing blade and laser dicing are not required.

Japanese Patent Application Laid-Open No. 2006-140311 JP 2016-193453 A

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

To address this problem, the laser processing apparatus disclosed in Patent Document 2 includes a laser light distribution observation device that observes the distribution of laser light guided by the liquid jet. In this laser light distribution observation device, since the shielding plate and the photodetector are arranged in a mutually conjugate positional relationship with respect to the imaging lens, the distribution of the laser light at the contact surface between the liquid jet and the shielding plate is photodetected. It can be faithfully reproduced on the light receiving surface of the instrument. This makes it possible to observe the distribution of the laser light guided by the liquid jet.

However, in the laser processing apparatus disclosed in Patent Document 2, before laser processing is started, adjustment is performed so that the distribution of laser light observed by the laser light observation device is appropriate. However, in order to obtain an arbitrary machining shape (target machining shape), it was necessary to repeat machining a plurality of times in one machining pass.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances. It is an object of the present invention to provide a laser processing apparatus and a laser processing method that can

In order to achieve the above object, a laser processing apparatus according to a first aspect of the present invention includes a laser oscillator, a processing head that irradiates a laser beam output from the laser oscillator onto a workpiece while guiding the laser beam with a liquid jet, moving means for moving the machining head and the workpiece relative to each other; high-speed deflecting means for deflecting the laser beam at high speed on the way from the laser oscillator to the machining head; By changing the deflection conditions of the high-speed deflection means, the laser beam distribution in the liquid jet on the laser beam irradiation surface of the workpiece can be changed in a plurality of ways. fast deflection control means for switching to distribution.

A laser processing apparatus according to a second aspect of the present invention, in the first aspect, includes low-speed deflection means for deflecting laser light output from a laser oscillator toward the machining head, and the high-speed deflection means is faster than the low-speed deflection means. Deflection at high speed and narrow range.

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

According to a fourth aspect of the present invention, there is provided a laser processing apparatus according to any one of the first to third aspects, wherein the high-speed deflection control means is configured such that the peak position of the laser light in the laser light distribution is the processing head and the workpiece. The deflection conditions of the high-speed deflection means are changed so that scanning is performed in a direction orthogonal to the direction of relative movement with the .

A laser processing apparatus according to a fifth aspect of the present invention, in any one aspect of the first aspect to the fourth aspect, comprises surface condition measuring means for measuring the condition of the surface of the workpiece, and the high-speed deflection control means comprises , changing the deflection conditions of the high-speed deflection means based on the measurement result of the surface state measuring means;

A laser processing method according to a sixth aspect of the present invention includes a laser beam irradiation step of irradiating a laser beam guided by a liquid jet onto a workpiece, and a moving step of relatively moving the liquid jet and the workpiece. a high-speed deflection step in which the laser beam is deflected at high speed before entering the liquid jet; A high-speed deflection control step is provided for switching the laser light distribution in the liquid jet on the laser light irradiation surface of the workpiece to a plurality of distributions by changing the deflection conditions when the laser light is applied.

According to the present invention, when a workpiece is processed with a laser beam guided by a liquid jet, the laser beam is deflected at high speed to actively control the distribution of the laser beam in the liquid jet, thereby achieving one The target machining shape can be obtained without repeating machining in the machining path.

Schematic diagram showing the configuration of a laser processing apparatus according to the first embodiment Simplified diagram showing laser light path in liquid jet The figure which showed the result of having observed the distribution of the laser beam in the position shown to a of FIG. The figure which showed the result of having observed the distribution of the laser beam in the position shown to b of FIG. A diagram showing the depth profile of a machined groove when a straight machined groove is formed in the workpiece under the same conditions as in FIG. A diagram showing the depth profile of the machined groove when a straight machined groove is formed in the workpiece under the same conditions as in FIG. Explanatory drawing schematically showing the case where laser processing is performed with the laser beam distribution in the liquid jet kept 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. FIG. 4 is a diagram for explaining the processing result when performing laser processing while switching the laser light distribution in the liquid jet between two distributions by a high-speed deflection means; FIG. 4 is a diagram for explaining the processing result when performing laser processing while switching the laser light distribution in the liquid jet between two distributions by a high-speed deflection means; FIG. 4 is a diagram for explaining the processing result when performing laser processing while switching the laser light distribution in the liquid jet between two distributions by a high-speed deflection means; Flowchart showing an example of a laser processing method using the laser processing apparatus according to the first embodiment A diagram showing an example of a lookup table The figure which showed the 1st example of the calculation method of an anticipated machining shape The figure which showed the 1st example of the calculation method of an anticipated machining shape The figure which showed the 2nd example of the calculation method of an anticipated machining shape The figure which showed the 2nd example of the calculation method of an anticipated machining shape The figure which showed the 2nd example of the calculation method of an anticipated machining shape The figure which showed the 3rd example of the calculation method of an anticipated machining shape The figure which showed the 3rd example of the calculation method of an anticipated machining shape The figure which showed the 3rd example of the calculation method of an anticipated machining shape Double logarithmic graph showing an example of correspondence between irradiation fluence and processing rate Conceptual diagram for explaining a laser processing method when laser processing is performed in a state where the laser beam distribution in the liquid jet is constant in one processing pass. Schematic diagram showing the configuration of a laser processing apparatus according to a second embodiment A diagram for explaining the effect of phase adjustment by a spatial light phase modulator Schematic diagram showing the configuration of a laser processing apparatus according to a third embodiment A diagram for explaining the effect of the third embodiment. A diagram for explaining the effect of the third embodiment.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a schematic diagram showing the configuration of a 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 section 18, a liquid supply means 20, a head unit 22, and a laser beam distribution observation device. A device 26 and a control unit 30 are provided.

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

The laser oscillator 14 outputs laser light L using power supplied from the laser power supply 12 . As the laser light L, a laser light in a wavelength range that is not easily absorbed by water is used.

The work table 16 has a holding surface 16a that holds the workpiece W (workpiece) by suction. 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 has 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 configured to be movable in the θ direction (rotational direction about the Z-axis) by a θ drive mechanism (not shown). A work table 16 is mounted 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. Note that 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 pressurized liquid (for example, pressurized water) to the processing head 40 .

The head unit 22 includes a deflection section 36 , beam 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 driving mechanism (not shown). The Z table is arranged on a Y table configured to be movable in the Y direction by a Y driving mechanism (not shown). Therefore, the head unit 22 is configured to be movable in the Y and Z directions.

The deflector 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 opposing two galvanometer mirrors (not shown) that can swing about axes perpendicular to each other, and deflects the laser light L by swinging the two galvanometer mirrors. , the incident angle and the incident position with respect to the liquid jet J ejected from the processing head 40 (liquid jet nozzle 48) can be changed. The deflection section 36 is an example of a low speed deflection means.

The beam shape shaping means 38 is arranged between the deflection section 36 and the processing head 40 and shapes the laser beam L input from the laser oscillator 14 via the deflection section 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 finely moving these in a direction orthogonal to the laser beam L. The laser beam L is shaped into a predetermined shape, size, and intensity distribution before being incident on the . In addition, the laser light L can be statically or dynamically controlled, including branching of the laser light L, by using an AOD (acousto-optic deflection element), an SLM (spatial modulation element), a DMD (Digital Mirror Device), a diffraction element, calcite, or the like. can also be formatted.

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

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

The condenser lens 42 is arranged in front of (above) the head main body 44, and condenses the laser beam L incident from the laser oscillator 14 via the deflector 36 and the beam shaping means 38 toward the inside of the head main body 44. do.

A liquid chamber 46 is defined inside the head body 44 . The liquid chamber 46 contains high pressure liquid supplied from the liquid supply means 20 . A liquid jet injection nozzle 48 is provided in the lower portion of the head main 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 contained in the liquid chamber 46, and the work W (or laser beam distribution observation described later) is discharged from the liquid jet injection nozzle 48. A liquid jet J is directed towards the shielding plate 52) of the device 26 .

A window portion 50 is provided in the upper portion of the head body 44 . The window part 50 is made of a light-transmitting member (for example, quartz glass) that is optically transparent to the laser light L, seals the liquid chamber 46, and allows the laser light L to pass therethrough. Therefore, the laser light L emitted from the condenser lens 42 passes through the window 50 , enters the inside of the head body 44 (liquid chamber 46 ), and is condensed on the liquid jet injection nozzle 48 .

In this embodiment, as an example, the work table 16 is configured to be movable in the X and θ directions, and the head unit 22 is configured to be movable in the Y and Z directions. 16 and the head unit 22 may be configured to be relatively movable in the X, Y, Z, and θ directions. The same applies to other embodiments described later.

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

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

The laser light distribution observation device 26 has an observation device drive mechanism (not shown) and is configured to be movable in the X, Y and Z directions. Thereby, the laser light distribution observation device 26 can move between an observation position facing the processing head 40 and a retracted position spaced apart from the observation position.

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

The shielding plate 52 is provided on the upper surface of the laser light distribution observing device 26 (the surface facing the processing head 40). The shielding plate 52 is made of a light-transmitting member (for example, quartz glass) that is optically transparent to the laser beam L, shields the liquid jet J, and transmits the laser beam L therethrough. Therefore, while the liquid of the liquid jet J ejected from the liquid jet ejection nozzle 48 of the processing head 40 is shielded by the shielding plate 52, the laser beam L guided by the liquid jet J is transmitted through the shielding plate 52, The light enters 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 relative to the processing head 40 . The distance between the machining head 40 and the shielding plate 52 should be equal to the distance between the machining head 40 and the workpiece W. That is, the length of the liquid jet J when the liquid jet J is ejected from the machining head 40 to the workpiece W and the length of the liquid jet J when the liquid jet J is ejected from the machining head 40 to the shielding plate 52 are different from each other. As long as they are equal, it is not always necessary that the work W and the shielding plate 52 have the same height in terms of absolute coordinates. For example, even if the heights of the workpiece W and the shielding plate 52 are different in terms of absolute coordinates, the heights relative to the processing head 40 should 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 workpiece W by moving the head unit 22 (processing head 40) or the laser light distribution observation device 26 in the Z direction. adjusted to

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 the residual liquid by absorption, a liquid suction means for removing the residual liquid by suction, a liquid blowing means for removing the residual liquid by blowing air, or a combination of these is appropriately used. can be adopted. As the liquid absorbing means, it is preferable to employ a configuration in which a fibrous belt-shaped member such as cloth is brought into contact with the surface of the shielding plate 52 so that the remaining liquid is absorbed by the belt-shaped member using capillary action. can.

The imaging lens 56 is arranged between the shielding plate 52 and the photodetector 58 inside the body portion 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 mutually conjugate positional relationship with respect to the imaging lens 56, and the laser beam distribution in the liquid jet J at the contact surface between the liquid jet J and the shielding plate 52 is is faithfully reproduced on the light receiving surface of the photodetector 58 by the imaging lens 56 .

The photodetector 58 receives a projected image representing the laser light distribution within 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 (electrical signal) corresponding to the amount of received light as laser light distribution data. As the photodetector 58, for example, a solid-state imaging device 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 of observing the laser light distribution in the liquid jet J by the laser light distribution observing device 26 will be described.

First, the laser light distribution observation device 26 is moved to an observation position (a position facing the processing head 40) by an observation device driving mechanism (not shown). The shielding plate 52 is arranged at the same height as the work W held on the work table 16 relative 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 contained in the liquid chamber 46 , and a liquid jet J is ejected from the liquid jet ejection nozzle 48 toward the shielding plate 52 .

In addition, the laser beam L output from the laser oscillator 14 is deflected toward the processing head 40 by the deflector 36 via the high-speed deflector 68 (to be described later), and the beam shape shaping device 38 directs the laser beam L to a predetermined shape, size, and intensity. After being shaped into a distribution, it enters the condenser lens 42 . Furthermore, the laser beam L is condensed by the condensing lens 42 to the liquid jet injection nozzle 48 through the window portion 50 . As a result, the laser light L is guided to 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 ejection nozzle 48 is shielded by the shielding plate 52, and the laser light L guided by the liquid jet J passes through the shielding plate 52 and passes through the imaging lens 56. An image is formed on the light receiving surface of the detector 58 . At this time, since the shielding plate 52 and the photodetector 58 are arranged in a positional relationship that is optically conjugate 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 is faithfully reproduced on the light-receiving surface of the photodetector 58 by the imaging lens 56 .

When a projected image representing the laser beam 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 outputs a laser output signal corresponding to the amount of received light. It outputs to the control part 30 as light distribution data. The controller 30 performs various processes on the input laser beam distribution data, and displays an image on the monitor 64 based on the processed laser beam distribution data.

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

Further, when the laser light distribution in the liquid jet J is observed by the laser light distribution observing device 26, the liquid (residual liquid) in the liquid jet J that is blocked by the shielding plate 52 is removed by the liquid removing means 54. Therefore, the laser light distribution in the liquid jet J can be stably and accurately observed without being affected by scattering of the laser light L due to the residual liquid on the shielding plate 52 .

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

The high-speed deflector 68 deflects the laser beam L at high speed on the way from the laser oscillator 14 to the processing head 40 (that is, before entering the liquid jet J). That is, the high-speed deflection means 68 deflects the laser light L output from the laser oscillator 14 within a predetermined angle range, and switches the deflection angle and emission direction of the laser light L at high speed. As the high-speed deflection means 68, for example, an AOD (acousto-optic deflection device) is preferably used. The AOD deflects the laser light 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 controller 30 (an example of high-speed deflection control means).

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

The machining shape measuring means 72 is arranged at a position adjacent to the machining head 40 . The machining shape measuring means 72 is means for three-dimensionally measuring the machining shape formed on the surface of the workpiece W by the machining head 40 . As the machined shape measuring means 72, a non-contact type that performs measurement without contacting the surface of the work W is preferable, and for example, a laser microscope, a white light interference microscope, or the like can be preferably employed. The three-dimensional data (machining shape data) of the machining shape measured by the machining shape measuring means 72 is output to the control section 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 section 30 controls operations of the laser oscillator 14, the work table moving section 18, the liquid supply means 20, the head unit 22, the high speed deflection means 68, the machining shape measuring means 72, and the like.

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

Here, the operation principle of laser processing performed by the laser processing apparatus 10 of this embodiment will be described. In the following, first, the laser beam distribution within the liquid jet J will be described, and then the effects of performing laser processing while switching the laser beam distribution within the liquid jet J to a plurality of distributions by the high-speed deflection means 68 will be described. do.

FIG. 2 is a simplified diagram showing the laser light path in the liquid jet J when the laser light L is incident coaxially with the central axis of the liquid jet J. As shown in FIG. Since the liquid jet J has a function similar to that of an SI-type multimode optical fiber, the movement speed of the liquid jet J in the central axis direction (longitudinal direction) changes depending on the angle of entry into the liquid jet J. , they interfere with each other, and are complicated by speckle noise generated by fine irregularities on the cylindrical outer peripheral surface (columnar surface) of the liquid jet J. Here, a simplified diagram is shown for ease of explanation. will be used to explain.

As shown in FIG. 2, when the laser beam L condensed by the condenser lens 42 is incident coaxially with the central axis of the liquid jet J, the laser beam L repeats expansion and contraction in the liquid jet J due to total reflection. Guided along the central axis direction. For example, since the position shown in FIG. ) spread uniformly over the entire liquid jet diameter. On the other hand, since the position shown in FIG.

3 and 4 are diagrams showing the results of actual observation of the distribution of the laser light L at positions corresponding to the position shown in FIG. 2a and FIG. 4 corresponding to the position shown in FIG. 2b, respectively. 5 and 6 are diagrams showing depth profiles of machined grooves when linear machined grooves are formed in the work W under the same conditions as in FIG. 3 and under the same conditions as in FIG. 4, respectively.

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

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

Next, a description will be given of the effects of performing laser processing while switching the laser light distribution in the liquid jet J between a plurality of distributions by the high-speed deflection means 68. FIG.

FIG. 7 is an explanatory diagram schematically showing a case where laser processing is performed with the laser beam distribution in the liquid jet J kept constant. 8 to 10 are explanatory diagrams schematically showing cases where laser processing is performed while switching the laser light distribution in the liquid jet J between a plurality of distributions. In addition, on the left side of these figures, the liquid jet J is moved relative to the work W in the processing feed direction (the direction along the planned cutting line) M to form a linear processing groove K in the work W. 2 shows the trajectory of the peak position Q of the laser light L guided by the liquid jet J (the position where the light intensity of the laser light L is the highest on the surface of the workpiece W) when the liquid jet J is applied. Further, the right side of these figures shows the depth profile of the machined groove K formed in the workpiece W. As shown in FIG.

In addition, in each figure, for the sake of simplicity of explanation, it is assumed that the peak position Q of the laser light L in the liquid jet J has a uniform intensity. In addition, although the peak positions Q of the laser beam L in the liquid jet J are depicted as being sufficiently separated from each other, if it is desired to form a uniform processing groove in the processing feeding direction M, the spatially 90% or more Laser processing is preferably performed under overlapping conditions.

As shown in FIG. 7, when laser processing is performed with the laser beam distribution in the liquid jet J kept constant, the peak position Q of the laser beam L in the liquid jet J is along the processing feed direction M. They are arranged in a row. Therefore, in the processed groove K, the processed depth at the position corresponding to the peak position Q of the laser beam L in the liquid jet J is deeper than the processed depth at other positions. In such a case, in order to make the machining depth of the machined 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. 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 light L in the liquid jet J is It is possible to change Q in the direction orthogonal to the feed direction M (the width direction of the machined groove).

In the example shown in FIG. 8, when laser processing is performed while the liquid jet J is moved relative to the workpiece W in the processing feed direction M, the peak position Q of the laser beam L in the liquid jet J is set to Laser processing is performed while sequentially changing positions at predetermined intervals (pitch) P in a direction orthogonal to the direction M. As shown in FIG. In this case, the processing depth of the processing groove K can be made uniform over the entire width direction. Therefore, compared to the example shown in FIG. 7, a desired machining shape can be obtained without repeating machining in one machining pass, 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 located from one side (the upper side in FIG. 8) of the direction perpendicular to the feed direction M (the width direction of the machining groove K) to the other side. The peak position Q of the laser beam L in the liquid jet J changes at a constant interval P toward the side (lower side in FIG. 8), and the peak position Q of the laser beam L in the liquid jet J is the other end of the direction perpendicular to the feed direction M (FIG. 8 ), the peak position Q of the laser beam L in the liquid jet J is switched to one end in the direction orthogonal to the feed direction M, and thereafter in the same order as the liquid jet The peak position Q of the laser light L within 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 extends from one side (upper side in FIG. 9) to the other side (lower side in FIG. 9) in the direction perpendicular to the feed direction M. side), and when the peak position Q of the laser beam L in the liquid jet J reaches the end on the other side in the direction perpendicular to the feed direction M, the liquid jet The peak position Q of the laser light L in J sequentially changes from the other side to the one side in the direction orthogonal to the feed direction M at a constant interval P, and thereafter the laser light in the liquid jet J continues in the same order. The peak position Q of L changes sequentially. According to the example shown in FIG. 9, the interval P between the peak positions Q of the laser beams L adjacent in the direction perpendicular to the feed direction M is always constant. Switching traces of the peak position Q of the light L are less likely to appear, and it is possible to further improve processing quality in laser processing.

The example shown in FIG. 10 is a case in which the number of peak positions Q of the laser light L is distributed to both ends in the direction orthogonal to the feed direction M more than in the example shown in FIG. In this case, the processing depth at both end portions in the width direction of the processing groove K can be deeper than that at the central portion. Also, although illustration is omitted, when the number of times of the peak position Q of the laser beam L in the central portion in the direction orthogonal to the processing feed direction M is increased, the processing depth in the central portion in the width direction of the processing groove K is can be processed deeper than both ends.

As described above, in the laser processing apparatus 10 of the present embodiment, the laser beam L is deflected at high speed by the high-speed deflection means 68, thereby switching the laser beam distribution in the liquid jet J on the surface of the workpiece W to a plurality of distributions while performing 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 machining shape (target machining shape) can be obtained without repeating machining in one machining pass.

At this time, the control unit 30 functioning as high-speed deflection control means controls the 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 feed direction. 68 (deflection angle, deflection direction, and deflection timing).

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

11A and 11B are diagrams showing the results of observation by the laser light distribution observing device 26 of two laser light distributions to be switched by the high-speed deflection means 68. FIG. FIG. 12 shows projection data obtained by projecting the two laser beam distributions shown in FIG. 11 in a direction perpendicular to the 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 the two laser beam distributions shown in FIGS. 11 and 12 are alternately switched at the same ratio (1:1 use ratio in this example) to form a linear processing groove. Fig. 4 shows a groove depth profile; Here, while switching between two laser light distributions at 15 kHz by the high-speed deflection means 68, laser processing was performed while conveying the workpiece W at a moving speed (processing feed speed) in the processing feed direction (X direction) of 30 mm/s. It shows the results when This corresponds to switching the laser beam distribution in the liquid jet J every time the machining distance (moving distance of the workpiece W in the machining feed direction) advances by 2 μm. The processing depth of is a shape that is averaged over the entire width direction of the processing width.

When the switching speed of the laser light distribution in the liquid jet J is slow, the peak position Q of the laser light L in the liquid jet J changes along with the switching of the laser light distribution in the liquid jet J in the processing feed direction. Switch traces appear at the time of cutting, and an uneven shape is formed in the machined groove. For example, when the two laser beam distributions are alternately switched, when the laser processing is performed under the condition that the processing feed rate is 50 mm/s and the switching speed of the two laser beam distributions is 500 Hz, one laser beam Since the processing distance per distribution is 100 μm (that is, the laser beam distribution is switched every time the processing distance advances by 100 μm), unevenness is formed every 100 μm in the processing feed direction (longitudinal direction of the processing groove).

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

Next, a laser processing method using the laser processing apparatus 10 according to this embodiment will be described with reference to FIG. FIG. 14 is a flow chart showing an example of a laser processing method using the laser processing apparatus 10 according to this embodiment. Note that each process is executed under the control of the control unit 30 unless otherwise specified.

(Step S10: Target Machining Shape Setting Step)
First, when one processing shape is selected by the user from a plurality of processing shapes registered in advance in the laser processing apparatus 10, the control unit 30 sets the selected processing shape as a target processing shape. Instead of selection by the user, the laser processing apparatus 10 may automatically set a predetermined default shape as the target machining shape. 15, the laser processing apparatus 10 includes 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 memory (not shown) stores a reference table (lookup table) showing the correspondence between the use 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. ing. A plurality of laser light distributions (for example, laser light distributions PT1 and PT2) corresponding to the same machining shape can be realized by changing the deflection pattern (deflection angle and deflection direction) of the high-speed deflection means 68. do.

(Step S12: Laser light distribution setting step)
Next, the control unit 30 adjusts the processing conditions of each part of the apparatus (for example, the mirror angle, etc.). It is assumed that the laser processing apparatus 10 pre-stores processing conditions for each part of the apparatus corresponding to each processing shape as internal values in a memory (not shown).

(Step S14: laser light distribution acquisition step)
Next, the laser light distribution inside the liquid jet J is observed by the laser light distribution observation device 26 . At this time, if the laser light distribution observation device 26 is not at the laser light distribution observation position (position facing the processing head 40), it is moved to the observation position by an observation device driving mechanism (not shown). Further, 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 intensity of the laser light L is adjusted by the shape shaping means 38 so as to be low. Laser light distribution data indicating the laser light distribution in the liquid jet J observed by the laser light distribution observing device 26 is output to the controller 30 . Observation of the laser light distribution in the liquid jet J by the laser light distribution observing device 26 is performed for all laser light distributions corresponding to the target machining shape.

(Step S16: Expected Machining Shape Calculation Step)
Next, the control unit 30 functions as an expected machining shape calculation means, and based on the laser beam distribution observed in the laser beam distribution acquisition step (step S14), the expected machining of the workpiece W by the machining head 40 is performed. Calculate the machining shape. Specifically, the laser light distribution data representing each laser light distribution observed by the laser light distribution observation device 26 is converted into projection data projected in a direction orthogonal to the feed direction. Then, the projection data of each laser beam distribution is multiplied by the use ratio (see FIG. 15) of each laser beam distribution and added together to calculate the expected machining shape. Note that the expected machining shape calculated by the control unit 30 is displayed on the monitor 64 . This allows the user to easily grasp the expected machining shape after machining.

Here, a method for calculating the expected machined shape will be described with reference to FIGS. 16 to 23. FIG.

16 and 17 are diagrams showing a first example of a method for calculating an expected machining shape.

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

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

Using such laser beam distributions 100A and 100B, the calculation result of the expected machining shape 200A when laser machining is performed while switching the laser beam distributions 100A and 100B at a usage ratio of 1:1 in one machining pass is calculated. It is shown in FIG. The expected machining shape 200A shown in FIG. 17 is obtained by multiplying the two laser light distributions 100A and 100B shown in FIGS. can be obtained by

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

The two laser light distributions 100C and 100D shown in FIGS. 18A and 18B have the same biased shape as the two laser light 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 beam distributions 100C and 100D, the calculation result of the expected machining shape 200B when laser machining is performed while switching the laser beam distributions 100C and 100D at a usage ratio of 1:1 in one machining pass is calculated. It is shown in FIG. In this case, since the two laser beam distributions 100C and 100D have different peak intensities, when the usage ratio is set to 1:1, as shown in FIG. It is not uniform in the width direction (horizontal direction in the figure).

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

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

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

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

In addition, the expected processing shape 200E when laser processing is performed while switching the laser light distributions 100E, 100F, and 100G with the use ratio of the laser light distributions 100E, 100F, and 100G set to 2:1:2 in one processing pass. Calculation results are shown in FIG. When the peak intensities of the three laser beam distributions 100E, 100F, and 100G are different, by reducing the use ratio of the central laser beam distribution 100F, which has a higher integrated ratio, the expected machining shape 200E shown in FIG. The bottom surface of the machined groove can be made uniform over the width direction, as compared with the expected machined shape 200D shown in FIG.

In this way, even if the peak intensities of the plurality of laser beam distributions are different, it is possible to obtain an arbitrary processed shape by adjusting their usage ratio.

Further, when laser processing is performed while switching three or more laser light distributions within one processing pass, more fine adjustment of the processing shape becomes possible by distributing the respective distributions at an arbitrary ratio.

In order to simplify the explanation here, it was explained that the sum of the laser beam distributions is directly reflected in the processed shape, but in general the processing rate (R) is proportional to the irradiation fluence (F). is known to be expressed by the following equation instead of

R=C1*ln(F _{/ C2} )
In addition, ln indicates a natural logarithm, and C ₁ and C ₂ indicate constants.

FIG. 24 is a double logarithmic graph showing an example of the correspondence relationship between the irradiation fluence and the processing rate, where the horizontal axis represents the logarithm of the irradiation fluence and the vertical axis represents the logarithm of the processing rate. Here, a point to be especially noted is that, as can be seen from FIG. 24, each work material has a threshold value for the irradiation fluence. If part of the laser light distribution (light intensity distribution) has an irradiation fluence below the threshold, that part will not contribute to processing, and a difference will occur from the calculation result of the expected processing shape by simple addition. need to be careful.

(Step S18: determination step)
Next, the control unit 30 compares the expected machining shape calculated in the expected 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 so, the process proceeds to the next step S20. On the other hand, if it is determined that the error is not within the allowable error range, the process proceeds to step S26.

(Step S20: Test processing step)
Next, using a test machining work, a test is performed on the test machining work under the machining conditions when it is judged that the error indicating the difference between the two shapes is within the allowable error range in the judgment step (step S18). process.

(Step S22: Machining shape measurement step)
Next, the machined shape measuring means 72 measures the machined shape of the machined groove formed in the work for test machining. 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. Machining shape data (three-dimensional shape data) representing the machining shape measured by the machining shape measuring means 72 is output to the control section 30 .

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

(Step S26: laser beam distribution adjustment step)
If it is determined in the determination step (step S18) that the error indicating the difference between the expected machining shape calculated in the expected machining shape calculation step (step S16) and the target machining shape is not within the allowable error range, or the machining shape If it is determined in the comparing step (step S24) that the error indicating the difference between the machining shape data obtained in the machining shape measuring step (step S22) and the target machining shape data is not within the allowable error range, the control unit Reference numeral 30 functions as a laser beam distribution adjusting means, and adjusts the laser beam distribution within the liquid jet J so as to reduce the error. After that, the process returns to step S12, and the processing conditions of each part of the apparatus are set (changed) so as to realize the laser beam distribution after adjustment, and the same processing is repeated. Note that the laser light distribution adjustment step includes changing the use ratio of each laser light distribution when there are a plurality of laser light distributions corresponding to the target machining shape.

(Step S28: main processing step)
If 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 allowable error range , the control unit 30 carries out the main machining process under the machining conditions adjusted up to that point. It should be noted that the laser light distribution observation device 26 moves to the retracted position when the main processing step is performed.

In this machining process, the control unit 30 relatively moves the workpiece W sucked and held on the holding surface 16a of the work table 16 and the machining head 40 in the machining feed direction (X direction) (an example of the movement process). A liquid jet J is jetted toward the work W from the liquid jet jet nozzle 48 of the processing head 40, and the work W is irradiated with the laser light L guided by the liquid jet J (an example of the laser light irradiation process). . As a result, a groove having a predetermined depth is formed in the workpiece W along the dividing line without causing film peeling, burrs, or the like.

At this time, the control unit 30 performs laser processing while switching the laser beam distribution in the liquid jet J between 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 deflection step). an example of the deflection control process). As a result, the target machining shape can be obtained without repeatedly performing machining in one machining pass.

When the formation of the machined grooves for one line is completed, the Y table on which the head unit 22 is attached is index-fed in the Y direction, and the machined grooves for the next line are similarly formed.

When the machined grooves are formed along all the planned cutting lines parallel to the X direction, the .theta. rotary table 34 is rotated by 90.degree., and the machined grooves are formed on all the lines perpendicular to the previous lines in the same way.

As described above, according to the present embodiment, the laser beam L is deflected at high speed by the high-speed deflection means 68, thereby performing laser processing while switching the laser beam distribution within the liquid jet J on the surface of the workpiece W to a plurality of distributions. be able to. This makes it possible to actively control the laser beam distribution in the liquid jet J and obtain the target machining shape without repeatedly performing machining in one machining pass.

Further, in the present embodiment, the surface of the workpiece W is adjusted so 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 light distribution in the liquid jet J at . Therefore, in order to obtain the target machining shape, it is not necessary to manually repeat several cycles of adjusting the laser beam distribution and evaluating the machining shape. By shortening the time, it is possible to reduce the number of man-hours and improve the production efficiency, and it is possible to obtain the target machining shape with high accuracy.

In addition, in the present embodiment, based on the laser light distribution observed by the laser light distribution observation device 26, it is possible to calculate the expected machining shape when the work W is machined by the machining head 40. The expected machined shape can be easily grasped. In addition, since feedback control is performed to adjust the laser beam distribution in the liquid jet J on the surface of the workpiece W so that the expected machining shape approaches the target machining shape, it is possible to efficiently obtain the target machining shape in a short time. becomes.

In this embodiment, when a pulsed laser is used as the laser light L, it is preferable that the repetition frequency of the pulsed laser is sufficiently high with respect to the switching speed (frequency) of the high-speed deflection means 68 .

Further, in the present embodiment, the angular range in which the high-speed deflector 68 deflects the laser beam L at high speed is set within the angular range in which the laser beam L can be incident on the liquid jet J (liquid jet incident angle range). However, it may be set wider than the liquid jet incident angle range. In this case, when the laser light L is deflected at high speed by the high-speed deflecting means 68, not only the pattern (laser light distribution) that causes the laser light L to enter the liquid jet J, but also the pattern that prevents the laser light L from entering the liquid jet J. (laser light distribution) can also be included. As a result, it is possible to reduce the substantial intensity of the laser beam L that irradiates the workpiece W, so that the processing shape can be controlled more extensively and precisely, and the processing shape can be maintained as it is. It becomes possible to control the processing rate itself according to the presence or absence.

Further, in the present embodiment, a case has been described in which laser processing is performed while switching the laser light distribution in the liquid jet J between a plurality of distributions in one processing pass. It may include a case where laser processing is performed in a state in which the laser beam distribution is kept constant.

FIG. 25 illustrates a laser processing method when laser processing is performed with the laser light distribution in the liquid jet J kept constant in one processing pass (that is, when one type of laser light distribution is used). It is a conceptual diagram for. Description will be made below with reference to FIG.

First, as shown in (a) of FIG. 25, when one processing shape is selected by the user from among a plurality of processing shapes (processing grooves) preset in the laser processing apparatus 10, the control unit 30 The selected machining shape is set as the target machining shape. Here, it is assumed that a machining shape indicating a rectangular machining groove, which is a portion surrounded by broken lines 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 adjusts the machining conditions of each part of the apparatus so that a laser beam distribution (target laser beam distribution) corresponding to the target machining shape is realized. set. FIG. 25(b) shows projection data obtained by projecting the target laser beam distribution in a direction orthogonal to the feed direction. 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 processing feed direction, and the vertical axis represents the position in the processing feed direction. Also, in FIG. 25(b), portions with high density (dark portions) correspond to portions with high laser beam intensity, and portions with low density (bright portions) in the drawing correspond to portions with low laser beam intensity. corresponds to The same applies to (g) of FIG. 25, which will be described later.

Next, the laser light distribution inside the liquid jet J is observed by the laser light distribution observation device 26 . FIG. 25(d) shows projection data (measured values) of the laser light distribution observed by the laser light distribution observation device 26. FIG. The dashed line in the figure is projection data (target value) of the target laser beam distribution shown in FIG. 25(b).

Next, the control unit 30 compares the laser light distribution observed by the laser light distribution observing device 26 with the target laser light distribution to calculate an error, and determines whether the error is within a preset allowable error range. determine whether If it is determined that the error is not within the allowable error range, control is performed so that the error becomes smaller (that is, the laser light distribution observed by the laser light distribution observing device 26 approaches the target laser light distribution). After adjusting the laser beam distribution, the unit 30 repeats the same processing until it is determined that the error is within the allowable range.

On the other hand, as shown in FIG. 25(d), the laser light distribution observed by the laser light distribution observation device 26 approximates the target laser light distribution, and the comparison error between the two is within the allowable error range. When the judgment is made, test machining is performed on the work for test machining under the machining conditions when the judgment was made.

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

Next, the control unit 30 compares the machining shape measured by the machining shape measuring means 72 with the target machining shape to calculate an error, and determines whether or not the error is within a preset allowable error range. do. When it is determined that the error is within the allowable error range, the main machining step is performed under the machining conditions when the determination was made.

On the other hand, as shown in (e) of FIG. 25, the error between the machining shape measured by the machining shape measuring means 72 and the target machining shape is not approximate, and the error resulting from the comparison of the two must be within the allowable error range. If so, the control unit 30, based on the result of comparing the machining shape measured by the machining shape measuring means 72 and the target machining shape, shifts the position to a position with a smaller error as the error in the comparison between the two increases. The target laser light distribution is adjusted so that the laser light intensity becomes relatively large compared to the target laser light distribution. An example of the target laser beam distribution after adjustment is shown in FIGS. 25(f) and 25(g). In the case shown in FIG. 25(e), since the error at the right side position in the figure is relatively large compared to the left side position in the figure, as shown in FIGS. The target laser light distribution is adjusted so that the laser light intensity at the middle right position is relatively high.

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

That is, as shown in (h) of FIG. 25, the adjustment was performed until the laser light distribution (actually measured value) observed by the laser light distribution observing device 26 approached the corrected target laser light distribution (target value). After that, further test machining is performed, and as shown in FIG. 25(i), adjustment is performed until the machining shape (actual measurement value) measured by the machining shape measuring means 72 approaches the target machining shape (measurement value). . Then, when it is determined that the error between the machining shape measured by the machining shape measuring means 72 and the target machining shape is within the allowable error range, the machining process is performed under the machining conditions when the judgment is made. implement.

As described above, even when laser processing is performed with the laser beam distribution in the liquid jet J being constant in one processing pass, the processing shape measured by the processing shape measuring means 72 is adjusted so as to approach the target processing shape. , feedback control for automatically adjusting the laser light distribution within the liquid jet J on the surface of the workpiece W is performed. Therefore, in order to obtain the target machining shape, it is not necessary to manually repeat several cycles of adjusting the laser beam distribution and evaluating the machining shape. By shortening the time, it is possible to reduce the number of 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 invention will be described. Hereinafter, the description of 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 diagram showing the configuration of a laser processing apparatus 10A according to the second embodiment. In FIG. 26, constituent elements common or similar to those in FIG.

As shown in FIG. 26, the laser processing apparatus 10A according to the second embodiment includes a reflecting mirror 37 and a spatial light phase modulator 70 between the laser oscillator 14 and the high-speed deflection means 68. 1 embodiment.

Reflecting mirror 37 reflects laser light L output from laser oscillator 14 toward spatial light phase modulator 70 .

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

FIG. 27 is a diagram for explaining the effect of phase adjustment by the spatial light phase modulator 70. FIG. FIG. 27 shows how the laser beam L condensed by the condensing lens 42 is incident on the liquid jet J. FIG. b) shows the case where the spatial light phase modulator 70 is provided (with phase adjustment).

As shown in FIG. 27(a), when the laser light L is condensed by the condensing lens 42 so as to be incident on the liquid jet J, the laser light L may have aberration. On the other hand, in this embodiment, as shown in FIG. Aberration can be corrected. Thereby, the laser beam distribution in the liquid jet J at the processing position (surface of the workpiece W) can be adjusted with high accuracy.

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

Further, by adjusting the phase of the laser light L using the spatial light phase modulator 70, it is possible to split the laser light L into a plurality of laser lights. As a result, it is possible to switch the laser light L including the pattern (laser light distribution) in which the laser light L is branched into a plurality of laser lights, and to form an arbitrary processed shape in detail and efficiently.

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

FIG. 28 is a schematic diagram showing the configuration of a laser processing apparatus 10B according to the third embodiment. In FIG. 28, constituent elements common or similar to those in FIG.

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

The work surface state measuring means 74 is means for measuring the state of the surface of the work W. As shown in FIG. The work surface state measuring means 74 is preferably a non-contact type that performs measurement without contacting the surface of the work W. For example, a spectral interference laser displacement meter, a sensor using a knife edge method, a camera, etc. can be done. The work surface state measuring means 74 may be any device that can measure the state of the surface 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 the surface of the work W without contacting the work W surface, and may measure the surface state of the work W by contacting the surface of the work W. may

According to this configuration, by measuring the state of the surface of the work W by the work surface state measuring means 74, it is possible to detect the position of the structure (for example, metal pad) on the line to be cut on the surface of the work W. can. The position of the structure on the planned cutting line thus detected is stored in a memory unit (not shown). Thereby, when laser processing is performed, it becomes possible to change the processing conditions according to the presence or absence of a structure on the planned cutting line. That is, laser processing is performed while switching the laser light distribution in the liquid jet J between a plurality of distributions so that the intensity of the laser light L is higher in a portion with a structure than in a portion without a structure. Even if there is a structure on the planned line (that is, if the machining rate is not uniform on the same planned cutting line), it is possible to make the machining depth uniform (uniform depth across the width direction). Become.

FIGS. 29 and 30 are diagrams for explaining the effect of the third embodiment. When forming the machined groove K along the planned cutting line in the work W, depending on the presence or absence of a structure on the planned cutting line, the It shows an example of the relationship between the amount of irradiation light (laser light intensity), processing rate, and processing depth when materials (hardness) different from each other are present. Here, it is assumed that the workpiece material G1 is harder than the workpiece material G2. Also, as shown in FIG. 8, the laser machining is performed while the peak position Q of the laser beam L in the liquid jet J is sequentially changed in the direction perpendicular to the feed direction M for machining. Note that the hardness here means the difficulty of processing with respect to the processing conditions (wavelength of the laser light L, etc.) to be used.

FIG. 29 shows a case where the processing conditions are constant regardless of the presence or absence of a 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 onto the surface of the work W is constant along the processing feed direction M, the following is shown in FIG. 29(c) As shown, 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 workpiece material G1 and the workpiece material G2, resulting in an uneven machining depth as a whole.

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

As described above, according to the laser processing apparatus 10B according to the third embodiment, the intensity of the substantial laser beam L irradiated to the work W is adjusted according to the position of the structure measured by the work surface state measuring means 74. By changing, it becomes 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 of course various improvements and modifications may be made without departing from the gist of the present invention. .

DESCRIPTION OF SYMBOLS 10... Laser processing apparatus 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 Apparatus 30 Control unit 32 X table 34 θ rotation table 36 Deflecting unit 37 Reflecting mirror 38 Beam shaping means 40 Processing head 42 Condensing lens 44 Head body , 46... liquid chamber, 48... liquid jet nozzle, 50... window, 52... shielding plate, 54... liquid removing means, 56... imaging lens, 58... photodetector, 60... main body, 64... monitor, 68... High-speed deflection means 70... Spatial optical phase modulator 72... Machining shape measuring means 74... Work surface state measuring means L... Laser beam J... Liquid jet

Claims (12)

a laser oscillator;
a processing head that irradiates a workpiece with a laser beam output from the laser oscillator while guiding the laser beam with a liquid jet;
moving means for relatively moving the machining head and the workpiece;
high-speed deflection means for high-speed deflection of the laser light on the way from the laser oscillator to the processing head;
By changing the deflection condition of the high-speed deflection means when irradiating the laser beam from the machining head to the workpiece while relatively moving the machining head and the workpiece by the moving means high-speed deflection control means for switching the laser light distribution in the liquid jet on the laser light irradiation surface of the workpiece to a plurality of distributions;
with
The high-speed deflection control means scans a peak position of the laser beam in the laser beam distribution in a direction orthogonal to a relative movement direction of the machining head and the workpiece during laser machining of the workpiece. changing the deflection conditions of the high-speed deflection means such that
Laser processing equipment. The high-speed deflection control means changes the peak position at regular intervals from one side to the other side in a direction perpendicular to the movement direction.
The laser processing apparatus according to claim 1. the high-speed deflection control means switches the peak position to the one-side end when the peak position reaches the other-side end;
The laser processing apparatus according to claim 2. The high-speed deflection control means changes the peak position at the constant interval from the other side toward the one side when the peak position reaches the end of the other side.
The laser processing apparatus according to claim 2. The high-speed deflection control means distributes the number of times of the peak positions arranged in the moving direction more to both ends than to the central portion in the direction orthogonal to the moving direction.
The laser processing apparatus according to any one of claims 1 to 4. The high-speed deflection control means distributes the number of times of the peak positions arranged in the movement direction more to the central portion than to both ends in the direction perpendicular to the movement direction.
The laser processing apparatus according to any one of claims 1 to 4. a laser beam irradiation step of irradiating a laser beam guided by a liquid jet onto a workpiece;
a moving step of relatively moving the liquid jet and the workpiece;
a high-speed deflection step of deflecting the laser light at high speed before entering the liquid jet;
When the laser beam is irradiated onto the workpiece while the liquid jet and the workpiece are moved relative to each other, the deflection condition for deflecting the laser beam at a high speed is changed to change the deflection condition of the laser beam. a high-speed deflection control step of switching the laser light distribution in the liquid jet on the laser light irradiation surface of the object to a plurality of distributions;
with
In the high-speed deflection control step, a peak position of the laser light in the laser light distribution is scanned in a direction orthogonal to a relative movement direction of the liquid jet and the work during laser processing of the work. changing the deflection conditions of the fast deflection step so as to
Laser processing method. The high-speed deflection control step changes the peak position at regular intervals from one side to the other side in a direction perpendicular to the moving direction.
The laser processing method according to claim 7. The high-speed deflection control step switches the peak position to the one-side end when the peak position reaches the other-side end.
The laser processing method according to claim 8. In the high-speed deflection control step, when the peak position reaches the end of the other side, the peak position is changed at the constant interval from the other side toward the one side.
The laser processing method according to claim 8. In the high-speed deflection control step, the number of times of the peak positions arranged in the moving direction is distributed more to both ends than to the central portion in the direction orthogonal to the moving direction.
The laser processing method according to any one of claims 7 to 10. In the high-speed deflection control step, the number of times of the peak positions arranged in the moving direction is distributed more to the central portion than to both ends in the direction orthogonal to the moving direction.
The laser processing method according to any one of claims 7 to 10.

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