JP2011177781A - Laser beam machining apparatus and laser beam machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam machining apparatus and a laser beam machining method, capable of executing the machining without causing any crack or the like even when cutting a brittle material having high residual stress. <P>SOLUTION: This invention relates to an apparatus for machining by irradiating a workpiece with a laser beam, and the apparatus includes a laser beam irradiation mechanism in which the laser beam is subjected to pulse oscillation to irradiate the workpiece with the laser beam at a fixed cyclic frequency, and scans the workpiece. In the laser beam applying mechanism, the laser beam scanning speed S is set to be L/(1/H), wherein H denotes the cyclic frequency H, a denotes the beam diameter of the laser beam, n denotes the scanning number of the laser beam on the same machining line, and the moving distance L of the pulse laser beam for one application which is expressed by n/2×a, and irradiation is performed while the application starting position is deviated for each scanning so that the application starting position Ln of the laser beam for the n-th scanning is set to L1+(L/n)×(n-1), wherein the application starting position of the laser beam for the first scanning is denoted as L1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus and a laser processing method suitable for, for example, cutting a brittle material.

  In general, cutting of a brittle material such as a fired ceramic sheet is performed by a mechanical method such as grinding with a grindstone. However, since sintered ceramic sheets and the like generate high residual stress inside by sintering, the lower the substrate thickness, the higher the residual stress and the occurrence of cracks at the start of processing. It was difficult to process so that there was no.

  Also known is a method of performing processing such as cutting by irradiating a fired ceramic sheet or the like with laser light and repeatedly scanning in order to obtain desired processing properties. For example, conventionally, Patent Document 1 discloses a brittle material cleaving method in which a strip made of a brittle material having a crack is heated by a point heat source such as a laser, and the crack is developed by moving the heating point to break the strip. Is described. Patent Document 2 describes a method of using a pulse laser for program-controlled dicing of a substrate including at least one layer, and a method of dicing the substrate by scanning the pulse laser.

JP-A-11-240730 JP 2005-523583 A

The following problems remain in the conventional technology.
In other words, even when using the conventional method of irradiating laser light, repeatedly scanning, inserting and scribing scribe grooves, cracks in unexpected directions during scribing due to thermal effects during processing and the dispersion of impurities Has occurred and has been divided.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a laser processing apparatus and a laser processing method capable of processing without causing a crack or the like even when cutting a brittle material having a high residual stress. To do.

  The present invention employs the following configuration in order to solve the above problems. That is, the laser processing apparatus of the present invention is an apparatus that irradiates a workpiece with a laser beam and processes the laser beam, oscillates the laser beam to irradiate the workpiece with a constant repetition frequency, and scans the laser beam. A laser beam irradiation mechanism, wherein the laser beam irradiation mechanism is H, the beam diameter of the laser beam is a, the number of scans of the laser beam on the same processing line is n, and the moving distance per irradiation of the pulsed laser beam When L is set to n / 2 × a, the laser beam scanning speed S is set to L / (1 / H), and the laser beam irradiation start position at the first scanning frequency is set to L1, and the laser at the nth scanning frequency. The light irradiation start position Ln is L1 + (L / n) × (n−1), and the irradiation is performed by shifting the irradiation start position for each scan.

  The laser processing method of the present invention is a method of processing by irradiating a processing target with laser light, and irradiating the processing target with laser light at a constant repetition frequency by oscillating the laser light in a pulsed manner. In the laser irradiation step, the repetition frequency is H, the beam diameter of the laser beam is a, the number of scans of the laser beam on the same processing line is n, and the moving distance L per irradiation of the pulsed laser beam is n / 2 × a, the laser beam scanning speed S is set to L / (1 / H), the laser beam irradiation start position at the first scanning frequency is set to L1, and the laser beam irradiation at the nth scanning frequency is performed. The start position Ln is L1 + (L / n) × (n−1), and the irradiation is performed by shifting the irradiation start position for each scan.

In these laser processing apparatuses and laser processing methods, the laser beam scanning speed S is set to L / (1 / H), the laser beam irradiation start position at the first scanning frequency is set to L1, and the laser at the scanning frequency n times. Since the irradiation start position Ln is set to L1 + (L / n) × (n−1) and the irradiation start position is shifted for each scan, it is possible to suppress a sudden change in the stress of the workpiece. Processing becomes possible without cracks.
That is, in order to fill up the moving distance L, which is the spot interval of the laser beam irradiated as a pulse to the object to be processed, while scanning the same processing line one after another while shifting the irradiation start position, the processing is repeated. Since the processing points are spaced apart at the time of scanning, the processing object is in a state where the processing objects are connected at an interval during the scanning and are difficult to break. In addition, when scanning is performed so that the processing points by the laser beam continuously overlap as in the conventional case, since the connected grooves are cut and extended, a sudden stress change occurs. On the other hand, in the present invention, the processing points are not continuous during one scan, and a rapid stress change can be suppressed.

In addition, the laser processing apparatus of the present invention includes an attachment jig for attaching and fixing the object to be processed, and a cooling mechanism for allowing a coolant to flow inside the attachment jig.
Moreover, the laser processing method of the present invention is characterized in that the irradiation is performed while circulating a coolant in the mounting jig.
That is, in these laser processing apparatuses and laser processing methods, since the coolant is circulated inside the mounting jig, the processing heat generated by the laser light is absorbed by the circulating coolant through the mounting jig, and brittle materials, etc. It is possible to prevent heat accumulation on the workpiece.

Further, the laser processing method of the present invention is characterized in that a resin film is bonded to the processing surface of the processing object, and the processing surface is irradiated with laser light from the resin film.
That is, in this laser processing method, a resin film is bonded to the processing surface of the workpiece, and laser light is irradiated onto the processing surface from above the resin film. Therefore, surplus energy other than the center of the laser light is generated by the resin film on the surface. It is absorbed and heat storage on a workpiece such as a brittle material can be prevented. In addition, the object to be processed can be mechanically held by the resin film, and generation of cracks, cracks, and the like can be suppressed.

In the laser processing method of the present invention, a metal film is bonded to the surface opposite to the processing surface of the processing object, and the processing object is fixed to the mounting jig by bringing the metal film into close contact with the mounting jig. And performing the irradiation.
That is, in this laser processing method, a metal film is bonded to the opposite surface of the processing target object, the metal film is brought into close contact with the mounting jig, and the processing target object is fixed to the mounting jig for irradiation. As a result, the workpiece to be processed can be mechanically held by the metal film, and the heat at the time of processing is radiated to the mounting jig through the metal film having high thermal conductivity, so that brittle materials, etc. are processed. Heat storage on the object can be prevented. In particular, by adopting an attachment jig provided with the cooling mechanism, a high heat dissipation effect can be obtained.

The present invention has the following effects.
That is, according to the laser processing apparatus and the laser processing method of the present invention, the laser beam scanning speed S is set to L / (1 / H), and the laser beam irradiation start position for the first scanning is set to L1. Since the irradiation start position Ln of the nth laser beam is set to L1 + (L / n) × (n−1) and the irradiation start position is shifted for each scanning, the stress of the workpiece changes rapidly. It is possible to process without suppressing cracking and the like.
Therefore, even when cutting a brittle material having a high residual stress, a stable process can be performed without causing cracks or cracks.

1 is a simple overall configuration diagram showing a laser processing apparatus in an embodiment of a laser processing apparatus and a laser processing method according to the present invention. In this embodiment, it is sectional drawing which shows a workpiece and an attachment jig. In this embodiment, it is explanatory drawing which shows the scanning method of a laser beam.

  Hereinafter, an embodiment of a laser processing apparatus and a laser processing method according to the present invention will be described with reference to FIGS. 1 to 3. In each drawing used for the following description, the scale is appropriately changed in order to make each member recognizable or easily recognizable.

  As shown in FIGS. 1 to 3, the laser processing apparatus 1 of the present embodiment is an apparatus that processes a workpiece W by irradiating the workpiece W with a laser beam L, and oscillates the laser beam L in a pulsed manner. A laser beam irradiation mechanism 2 that irradiates and scans W at a constant repetition frequency, a moving mechanism 3 that can move while holding the workpiece W, and a workpiece W that is installed on the moving mechanism 3 is attached. An attachment jig 4 to be fixed, a cooling mechanism 5 for circulating a coolant 5a inside the attachment jig 4, and a control unit 6 for controlling them are provided.

The workpiece W is a brittle material having a high residual stress such as a ceramic sintered substrate.
At the time of processing, as shown in FIG. 2, the resin film 7 is adhered to the processing surface (surface) of the processing target W, and the processing surface is irradiated with the laser light L from the resin film 7. Further, the metal film 8 is bonded to the opposite surface (back surface) of the processing object W, and the metal film 8 is brought into close contact with the mounting jig 4 to fix the processing object W to the mounting jig 4. And then irradiate.

As the resin film 7, a polytetrafluoroethylene film, a polyethylene terephthalate film, a polyethylene film, a polypropylene film, a polymethylpentene film, a plastic film such as polyvinyl chloride, an ultraviolet transmissive film such as polyolefin, and the like can be used.
The metal film 8 may be a metal tape such as aluminum, copper, stainless steel (SUS). The metal film 8 is bonded to the workpiece W with an adhesive mainly composed of acrylic rubber, urethane resin, silicone resin or the like.

In addition, as these resin film 7 and metal film 8, it is preferable to employ | adopt the film of the low thermal expansion coefficient from which the thermal expansion coefficient is the same as or close to the workpiece W, and the thermal expansion difference at the time of a process does not produce easily. For example, as the workpiece W, alumina (Al ₂ O ₃ ) having a thermal expansion coefficient of 8.8 × 10 ⁻⁶ / K or lanthanum gallate having a thermal expansion coefficient of 10.8 × 10 ⁻⁶ / K is processed. In this case, a low thermal expansion coefficient special resin (for example, low thermal expansion polyimide) having a thermal expansion coefficient of 6 to 10 × 10 ⁻⁶ / K is employed as the resin film 7. In this case, the metal film 8 is preferably SUS304 having a thermal expansion coefficient of 13.6 × 10 ⁻⁶ / K.

  The moving mechanism 3 includes an X-axis stage portion 3x that can move in the X direction parallel to the horizontal plane, and a moving direction in the Y direction that is provided on the X-axis stage portion 3x and that is perpendicular to the X direction and parallel to the horizontal plane. A Y-axis stage unit 3y and a Z-axis stage unit 3z provided on the Y-axis stage unit 3y and capable of holding the workpiece W by fixing the mounting jig 4 and moving in a direction perpendicular to the horizontal plane And is composed of.

The laser beam irradiation mechanism 2 includes a laser light source 9 having an optical system that oscillates a laser beam L in response to a trigger signal of a Q switch and condenses it in a spot shape, a galvano scanner 10 that scans the irradiated laser beam L, and a holding unit. And a CCD camera 11 that captures an image to confirm the processing position of the processed object W.
As the laser light source 9, one that can irradiate a laser beam L having a wavelength of 190 to 550 nm can be used. For example, in the present embodiment, a laser beam that can oscillate and emit a laser beam L having a wavelength of 355 nm is used. Yes.

The galvano scanner 10 is disposed immediately above the moving mechanism 3. The CCD camera 11 is installed adjacent to the galvano scanner 10.
The cooling mechanism 5 has a structure in which, for example, cooling water is circulated as a coolant 5a in a flow passage 5b provided in the mounting jig 4, and a supply source ( (Not shown) are connected.

  Further, the attachment jig 4 has a plurality of suction holes 4a formed on the attachment surface of the workpiece W, and these suction holes 4a are connected to a vacuum source (not shown) via a cavity 4b formed inside the jig. )It is connected to the. That is, the workpiece W placed on the mounting surface can be held by vacuum suction through the suction holes 4a. Thus, the attachment jig 4 is a water-cooled adsorption jig having a water-cooling function and a vacuum adsorption function.

  The laser beam irradiation mechanism 2 has a repetition frequency of H, a beam diameter of the laser beam L of a, a scanning frequency of the laser beam L on the same processing line of n, and a moving distance L per irradiation of the laser beam L of n / When 2 × a, the scanning speed S of the laser beam L is set to L / (1 / H), and the irradiation start position of the laser beam L with the first scanning frequency is set to L1, and the laser beam with the scanning frequency of n times is set to L1. The irradiation start position Ln is set to L1 + (L / n) × (n−1), and irradiation is performed by shifting the irradiation start position for each scan.

At this time, the time per pulse laser beam is 1 / H. The number of scans n is an arbitrary number that does not cause cracks and the like, and is set in a range in which the scan speed S can be controlled.
Further, the laser light irradiation mechanism 2 sets the laser output slightly higher than the processing threshold value of the processing object W.

  More specifically, as shown in FIG. 3, when the number of scans is 3 (n = 3), the scan is started from the irradiation start position L1 at the first scan, and the movement distance L is left on the processing line. Laser light L is irradiated at a set repetition frequency H and scanning speed S. For example, when the beam diameter a is 20 μm and the repetition frequency H is 10 kHz, the scanning speed S is set to 300 mm / sec. In the first scanning, since the machining is performed with an interval on the machining line, the workpiece W is connected between the machining points.

  Next, at the time of the second scanning, the irradiation start position of the laser beam L is set to L1 + (L / 2) and is shifted from the first irradiation starting position to scan on the same processing line as the first time. Further, at the time of the last third scanning, the irradiation start position of the laser beam L is set to L1 + (L / 3) × 2 and is shifted from the first and second irradiation start positions on the same processing line as the first time. Scan with. By the three scans, the workpiece W is completely cut on the machining line.

  As described above, in this embodiment, the scanning speed S of the laser light L is set to L / (1 / H), and the irradiation start position of the laser light L with the first scanning number is set to L1, and the laser light with the nth scanning number is used. Since the irradiation start position Ln of L is L1 + (L / n) × (n−1) and the irradiation start position is shifted for each scan, the stress of the workpiece W is prevented from changing abruptly. This makes it possible to process without cracks.

  That is, in order to overlap the processing by scanning the same processing line one after another while shifting the irradiation start position so as to fill the moving distance L that is the spot interval of the laser light L irradiated as a pulse to the workpiece W. Since the machining points are spaced apart during a single scan, the workpieces W are connected with a gap during the scan, and are difficult to break. In addition, when scanning is performed so that the processing points by the laser beam continuously overlap as in the conventional case, since the connected grooves are cut and extended, a sudden stress change occurs. On the other hand, in the present embodiment, the machining points are not continuous during one scan, and a rapid stress change can be suppressed.

Further, since the coolant 5a is circulated inside the mounting jig 4, the circulating heat 5a absorbs the processing heat through the mounting jig 4 to prevent heat accumulation on the workpiece W such as a brittle material. be able to.
Furthermore, since the resin film 7 is adhered to the processing surface of the processing target W and the processing surface is irradiated with the laser beam L from the resin film 7, surplus energy other than the center of the laser beam L is generated by the resin film 7 on the surface. It is absorbed and heat storage on the workpiece W such as a brittle material can be prevented.

  Further, the workpiece W being processed can be mechanically held by the resin film 7, and the occurrence of cracks, cracks, and the like can be suppressed. In particular, in the case where the laser beam L is continuously irradiated without being spaced apart on the processing line as in the conventional case, the periphery of the processing line of the resin film 7 is melted by heat and the groove width becomes wide, and the vicinity of the processing portion However, in this embodiment, since irradiation is performed at intervals, the influence of heat on the resin film 7 can be reduced, and the groove width can be controlled to be narrow.

  Further, the metal film 8 is bonded to the surface opposite to the processing surface of the processing object W, the metal film 8 is brought into close contact with the mounting jig 4, and the processing object W is fixed to the mounting jig 4 for irradiation. Therefore, the workpiece W being processed can be mechanically held by the metal film 8 and heat at the time of processing is radiated to the mounting jig 4 via the metal film 8 having high thermal conductivity, so that it is brittle. Heat storage on the workpiece W such as a material can be prevented.

Next, an embodiment when actually processed by the laser processing apparatus and the laser processing method according to the present invention will be specifically described.
In this example, a ceramic sintered body (thickness: 250 μm) was processed as a processing target with a laser beam having a wavelength of 355 nm using the laser processing apparatus of the present embodiment. At that time, a polyimide resin film (thickness: 0.1 mm) as a resin film was adhered to the surface of the ceramic sintered body with an acrylic adhesive, and an aluminum film (thickness: 0.05 mm) as a metal film was adhered to the back side as a silicone film. Bonded with an adhesive. The workpiece in this state was adsorbed on the mounting jig.

The laser beam output was set to 1.3 W, the repetition frequency H was set to 125 kHz, and the beam spot was measured. As a result, the beam diameter was 20 μm, so the galvano scanner was used to set the scanning speed S to 3750 mm / sec. Processing was performed three times.
As a result, a good cut surface without cracks could be obtained.

  The laser processing apparatus and laser processing method of the present invention are particularly suitable for cutting a brittle material having a high residual stress.

  DESCRIPTION OF SYMBOLS 1 ... Laser processing apparatus, 2 ... Laser beam irradiation mechanism, 4 ... Mounting jig, 5 ... Cooling mechanism, 5a ... Cooling liquid, 7 ... Resin film, 8 ... Metal film, L ... Laser beam, W ... Work object

Claims (6)

An apparatus for irradiating a processing object with laser light,
A laser light irradiation mechanism that oscillates and irradiates the workpiece with a constant repetition frequency by oscillating laser light, and scans,
The laser beam irradiation mechanism is configured such that the repetition frequency is H, the beam diameter of the laser beam is a, the number of times the laser beam is scanned on the same processing line is n, and the moving distance L per pulse laser beam is n / 2 ×. When a
The scanning speed S of the laser beam is set to L / (1 / H),
The irradiation start position of the first laser beam is set to L1, and the irradiation start position Ln of the nth laser beam is set to L1 + (L / n) × (n−1). And performing the irradiation. In the laser processing apparatus of Claim 1,
An attachment jig for attaching and fixing the workpiece;
And a cooling mechanism for circulating a coolant in the mounting jig. A method of processing by irradiating a processing object with laser light,
A laser irradiation step of oscillating and irradiating the workpiece with a constant repetition frequency by oscillating a laser beam;
In the laser irradiation step, the repetition frequency is H, the beam diameter of the laser beam is a, the number of scans of the laser beam on the same processing line is n, and the moving distance L per pulse laser beam irradiation is n / 2 × a. When
The scanning speed S of the laser beam is set to L / (1 / H),
The irradiation start position of the first laser beam is set to L1, and the irradiation start position Ln of the nth laser beam is set to L1 + (L / n) × (n−1). And performing the irradiation. In the laser processing method of Claim 3,
A laser processing method, comprising: bonding a resin film to a processing surface of the processing object; and irradiating the processing surface with laser light from the resin film. In the laser processing method according to claim 3 or 4,
A metal film is adhered to a surface opposite to a processing surface of the processing object, the metal film is adhered to a mounting jig, and the irradiation is performed with the processing object fixed to the mounting jig. Laser processing method. In the laser processing method of Claim 5,
A laser processing method, wherein the irradiation is performed while circulating a coolant in the mounting jig.

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