JP7442351B2 - laser processing equipment - Google Patents

Description

The present invention relates to a laser processing device.

In recent years, with the diversification of mobile device designs, display panels with shapes other than rectangles and display panels with curved surfaces have appeared. Additionally, as the shapes of display panels become more diverse, the shapes of glass used in the housings are also becoming more diverse. In order to process hard, brittle, and difficult-to-process materials such as glass and quartz into the desired shape, a shield tunnel is formed by irradiating the workpiece with a pulsed laser beam at a wavelength that is transparent. However, a processing method has been proposed in which a molded product having a desired shape is manufactured by removing the shield tunnel by etching.

In the method of forming and removing a shield tunnel described above, a workpiece is held by a chuck table placed on the X-axis and Y-axis, and the workpiece is processed while moving the chuck table while synchronizing the X-axis and Y-axis. By irradiating the object with a laser beam, it is possible to process it into the desired shape. These X-axis and Y-axis are operated by a motor, and the deviation is controlled by the motor itself (see Patent Document 1).

Japanese Patent Application Publication No. 2004-280772

However, the method of Patent Document 1 has a problem in that it is very difficult to bring the deviation due to the axis movement close to zero in microfabrication such as the above-described method of forming and removing shield tunnels.

The present invention has been made in view of these problems, and its purpose is to provide a laser processing device that can bring the deviation due to axis motion as close to zero as possible and realize highly accurate processing.

In order to solve the above-mentioned problems and achieve the objects, the laser processing apparatus of the present invention is a laser processing apparatus, which includes a chuck table that holds a workpiece, and a chuck table that holds a workpiece held on the chuck table. A laser beam irradiation unit that performs laser processing, a movement unit that relatively moves the chuck table and the laser beam irradiation unit, and a coordinate position of the planned shape to be processed, which is the area where the workpiece is to be irradiated with the laser beam. While the chuck table is being moved by the moving unit with respect to the laser beam irradiation unit according to the locus of the coordinate position of the to-be-processed shape stored in the storage unit, the chuck table is The laser beam irradiation unit includes a calculation unit that calculates a deviation that is the amount of deviation between the actual coordinate position and the coordinate position stored in the storage unit, and the laser beam irradiation unit includes a laser oscillator that emits a laser beam; a condenser that condenses a laser beam emitted from the laser oscillator and irradiates the workpiece held on the chuck table; and a condenser that is disposed between the laser oscillator and the condenser, a laser beam scanning unit that changes the traveling direction of the laser beam emitted from the oscillator to a desired direction; the moving unit controls the laser beam scanning unit to follow the trajectory of the coordinate position stored in the storage unit; The method further comprises a control unit that changes the traveling direction of the laser beam so as to cancel out the deviation calculated by the calculation unit while the chuck table is moved with respect to the laser beam irradiation unit. do.

In the laser beam irradiation unit, the laser oscillator emits a laser beam with a wavelength that is transparent to the workpiece, and the NA of the condenser is 0.3 or more and 0.8 or less. good. The system further includes a position detection unit that detects the position of the chuck table, and the calculation unit calculates the actual coordinate position of the chuck table obtained from the position detection unit and the processing of the chuck table obtained from the storage unit. The control unit is a circuit board that calculates the deviation, which is the amount of deviation, based on the coordinate position of the planned shape, and controls the laser beam scanning unit by receiving the deviation directly from the calculation unit. It's okay.

The present invention makes it possible to bring the deviation due to axis motion as close to zero as possible and realize highly accurate machining.

FIG. 1 is a perspective view showing a configuration example of a laser processing apparatus according to an embodiment. FIG. 2 is a diagram schematically showing an example of the functional configuration of main parts of the laser processing apparatus shown in FIG. FIG. 3 is a perspective view showing a configuration example of the laser beam scanning unit shown in FIG. 2. FIG. FIG. 4 is a diagram illustrating the effects of the laser processing apparatus according to the embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Further, the constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Moreover, various omissions, substitutions, or changes in the configuration can be made without departing from the gist of the present invention.

[Embodiment]
A laser processing apparatus 1 according to an embodiment of the present invention will be described based on the drawings. FIG. 1 is a perspective view showing a configuration example of a laser processing apparatus 1 according to an embodiment. FIG. 2 is a diagram schematically showing an example of the functional configuration of main parts of the laser processing apparatus 1 shown in FIG. 1. As shown in FIG. As shown in FIG. 1, the laser processing device 1 according to the embodiment includes a chuck table 10, a laser beam irradiation unit 20, a movement unit 30, a storage unit 40, a calculation unit 50, a control unit 60, and a device. A control unit 70 is provided. The laser processing apparatus 1 performs laser processing by irradiating a workpiece 100 held on a chuck table 10 with a laser beam 25 (see FIG. 2) using a laser beam irradiation unit 20 to form a shield tunnel in the workpiece 100. It is a device for forming. In this embodiment, the laser processing apparatus 1 creates a shield tunnel having a pore with an inner diameter of about 1 μm and an amorphous material with an outer diameter of about 5 μm surrounding the pore, by connecting the centers of adjacent shield tunnels to each other. They are formed with an interval of about 10 μm. Note that the laser processing device 1 is not limited to this in the present invention, and may be a device that forms a modified layer inside the workpiece 100, or may be a device that forms a processed groove by ablating the surface of the workpiece 100. A device that does this may also be used.

A workpiece 100 to be laser processed by the laser processing apparatus 1 is a disk-shaped material made of a hard, brittle, and difficult-to-process material such as glass, quartz, or ceramics. The workpiece 100 is formed so that at least one surface is flat. Further, in the present invention, the workpiece 100 may be a wafer such as a disk-shaped semiconductor wafer or an optical device wafer that uses silicon, sapphire, gallium arsenide, or the like as a base material.

The chuck table 10 holds the flat surface of the workpiece 100 with a holding surface 11. The chuck table 10 has a flat holding surface 11 for holding a workpiece 100 formed on the upper surface, and a disk-shaped suction part made of porous ceramic or the like having a large number of porous holes, and the suction part fixed to the upper surface. It is disc-shaped and has a fixing part. The holding surface 11 is formed parallel to the XY plane, which is a horizontal plane. The chuck table 10 has a suction section connected to a vacuum suction source (not shown) via a vacuum suction path (not shown), and suctions and holds the workpiece 100 on the entire holding surface 11 .

The laser beam irradiation unit 20 is fixedly provided on the main body 2 of the laser processing apparatus 1, as shown in FIG. As shown in FIG. 2, the laser beam irradiation unit 20 includes a laser oscillator 21, a condenser 22, and a laser beam scanning unit 23. The laser oscillator 21 oscillates a laser beam 25 of a predetermined wavelength. In this embodiment, the laser oscillator 21 oscillates a laser beam 25 having a wavelength that is transparent to the workpiece 100. Further, the laser oscillator 21 oscillates a pulsed laser beam 25 in this embodiment.

The condenser 22 condenses the laser beam 25 oscillated from the laser oscillator 21 and irradiates it toward the workpiece 100 held on the chuck table 10 . In this embodiment, the condenser 22 is, for example, a condenser lens. In this embodiment, the numerical aperture (NA) of the condenser 22 is 0.3 or more and 0.8 or less. In this embodiment, since the NA of the condenser 22 is 0.3 or more, the shield tunnel formed by modifying the workpiece 100 with the laser beam 25 is easily etched sufficiently. Further, in this embodiment, since the NA of the condenser 22 is 0.8 or less, the possibility that cracks will occur in the workpiece 100 due to the laser beam 25 and the bending strength will decrease is sufficiently suppressed. be done.

The laser beam scanning unit 23 is disposed on the optical path of the laser beam 25 between the laser oscillator 21 and the condenser 22, and is controlled by the control unit 60 to scan the laser beam 25 oscillated from the laser oscillator 21. change the direction of travel to the desired direction. In this embodiment, the laser beam scanning unit 23 is a resonant scanner, a galvano scanner, or an acousto-optic device (AOD). A specific example of the configuration of the laser beam scanning unit 23 will be described later.

The laser beam irradiation unit 20 oscillates a laser beam 25 using a laser oscillator 21 and changes the traveling direction to a desired direction using a laser beam scanning unit 23. The laser beam irradiation unit 20 focuses a laser beam 25 using a condenser 22 on the object held on the chuck table 10. By irradiating the laser beam toward the workpiece 100, the workpiece 100 is laser-processed to form a shield tunnel in the workpiece 100.

FIG. 3 is a perspective view showing an example of the configuration of the laser beam scanning unit 23 in FIG. 2. As shown in FIG. In this embodiment, the laser beam scanning unit 23 has a configuration as shown in FIG. 3. Specifically, as shown in FIG. 3, the laser beam scanning unit 23 includes a base portion 231, a shaft 232 fixed to the base portion 231, and a base 233 supported by the tip of the shaft 232. A scanning mirror 234 is provided. The laser beam scanning unit 23 is generally called a resonant scanner, and performs scanning by causing a scanning mirror 234 to resonate around the axis of the shaft 232.

The base portion 231 holds the shaft 232 and the scanning mirror 234, and is configured to be fixable at a predetermined installation location inside the laser beam irradiation unit 20. The shaft 232 is fixed to the base portion 231 in an upright position. The shaft 232 includes an arm portion 235 extending in a direction perpendicular to the axis 241 of the shaft 232 . This arm portion 235 includes tip portions 235-1, 235-2 located on a straight line with the axis 241 in between, and each tip portion 235-1, 235-2 is located at an equal distance from the axis 241. It is set in.

The laser beam scanning unit 23 also includes a drive section 238 that causes the scanning mirror 234 to resonate around the axis 241 via the shaft 232. The drive section 238 includes, for example, coils (not shown) that are wound around the arm section 235 with a space between them, a power supply section (not shown) that applies alternating current power to these coils, and a distal end section 235-1 of the arm section 235. , 235-2, respectively.

When AC power of a predetermined frequency (excitation frequency) is applied to these coils, the drive unit 238 causes the shaft 232 to be rotated by the magnetic poles generated at the tips 235-1 and 235-2 of the arm unit 235 and the magnetic force of the magnets. It resonates (excites) around the core 241 in the circumferential direction (direction of arrow 242). Therefore, in the scanning mirror 234 fixed to the shaft 232, as shown in FIG. .

The moving unit 30 includes an X-axis moving unit 31 and a Y-axis moving unit 32, as shown in FIG. The X-axis moving unit 31 moves the chuck table 10 in the X-axis direction, which is one horizontal direction, relative to the laser beam irradiation unit 20. The Y-axis moving unit 32 moves the chuck table 10 relative to the laser beam irradiation unit 20 in the Y-axis direction, which is another horizontal direction and perpendicular to the X-axis direction. In this way, the moving unit 30 moves the chuck table 10 and the laser beam irradiation unit 20 relatively within the XY plane using the X-axis moving unit 31 and the Y-axis moving unit 32, thereby moving the chuck table 10 upward. The irradiation position of the laser beam 25 by the laser beam irradiation unit 20 on the workpiece 100 is moved.

The X-axis moving unit 31 and the Y-axis moving unit 32 include a well-known ball screw rotatably provided around the axis, a well-known pulse motor that rotates the ball screw around the axis, and a well-known pulse motor that moves the chuck table 10 around the X-axis. It is provided with a well-known guide rail that is movably supported in the Y-axis direction or the Y-axis direction.

Further, as shown in FIG. 2, the laser processing apparatus 1 includes an X-axis position detection unit 33 for detecting the position of the chuck table 10 in the X-axis direction, and a position detection unit 33 for detecting the position of the chuck table 10 in the Y-axis direction. A Y-axis direction position detection unit 34 is provided. The X-axis direction position detection unit 33 and the Y-axis direction position detection unit 34 use a linear scale parallel to the X-axis direction or the Y-axis direction, and the X-axis movement unit 31 or the Y-axis movement unit 32 to detect the position in the X-axis direction or the Y-axis direction. and a reading head that is movably provided to read the scale of the linear scale. The X-axis direction position detection unit 33 and the Y-axis direction position detection unit 34 use information indicating the scale of the linear scale read by the reading head as information indicating the position of the chuck table 10 in the X-axis direction or the Y-axis direction. Output to calculation unit 50.

The storage unit 40 stores a planned shape to be processed, which is a region to which the laser beam 25 is to be irradiated on the workpiece 100, in coordinate positions. Specifically, in the present embodiment, the storage unit 40 stores the The locus of the position in the axial direction and the locus of the position in the Y-axis direction are stored as the locus of the coordinate position represented by the X coordinate and the Y coordinate, respectively. The storage unit 40 is electrically connected to the calculation unit 50 so as to be able to communicate information.

In this embodiment, the storage unit 40 includes RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (registered trademark) (Electrically Erasable Programmable Read Only Memory), etc. nonvolatile or volatile semiconductor memory, etc.

The calculation unit 50 calculates a deviation, which is the amount of deviation between the actual coordinate position of the moving unit 30 and the coordinate position of the planned shape to be machined, when the moving unit 30 is moved in the shape to be machined. Specifically, in the present embodiment, the calculation unit 50 continuously calculates the The deviation, which is the amount of deviation between the actual coordinate position of the chuck table 10 and the coordinate position stored in the storage unit 40, is calculated every minute or minute time.

In this embodiment, the calculation unit 50 includes an X-axis motor controller 51 and a Y-axis motor controller 52, as shown in FIG. The X-axis direction motor controller 51 detects the actual X-axis coordinate position of the chuck table 10 obtained from the X-axis position detection unit 33 and the set X-axis coordinate of the chuck table 10 obtained from the storage unit 40. Based on the position, the deviation in the X-axis direction, which is the amount of deviation in the X-axis direction, is calculated and output to the control unit 60. The Y-axis direction motor controller 52 detects the actual Y-axis coordinate position of the chuck table 10 obtained from the Y-axis direction position detection unit 34 and the Y-axis direction coordinate on the setting of the chuck table 10 obtained from the storage unit 40. Based on the position, a deviation in the Y-axis direction, which is the amount of deviation in the Y-axis direction, is calculated and output to the control unit 60.

The X-axis direction motor controller 51 and the Y-axis direction motor controller 52 each have a function of automatically canceling deviations in the X-axis direction and the Y-axis direction. The X-axis direction motor controller 51 and the Y-axis direction motor controller 52 each calculate the deviations in the X-axis direction and the Y-axis direction that cannot be canceled by their own deviation canceling functions, and Output to.

The control unit 60 controls the laser beam scanning unit 23 and changes the traveling direction of the laser beam 25 so as to cancel the deviation calculated by the calculation unit 50. In this embodiment, the control unit 60 controls the power supply section of the drive section 238 to apply alternating current power to the coil of the drive section 238 to cause resonance (excitation) in the direction of the arm section 235 about the axis 241. By causing the scanning mirror 234 to resonate around the axis of the shaft 232, the scanning of the laser beam scanning unit 23 is controlled. While the moving unit 30 is moving the chuck table 10 with respect to the laser beam irradiation unit 20 according to the trajectory of the coordinate position stored in the storage unit 40, the control unit 60 continuously or every minute time calculates the calculation unit 50. The calculated deviation is obtained from the calculation unit 50, and the traveling direction of the laser beam 25 is changed so as to cancel this deviation.

The control unit 60 is a circuit board in this embodiment. Therefore, since the control unit 60 receives the deviations in the X-axis direction and the Y-axis direction directly from the X-axis direction motor controller 51 and the Y-axis direction motor controller 52 that constitute the calculation unit 50, the The processing time from calculation to control of the laser beam scanning unit 23 is shortened, and the responsiveness from changing the traveling direction of the laser beam 25 to the occurrence of deviation is improved. This allows the control unit 60 to correct the irradiation position of the laser beam 25 on the workpiece 100 on the chuck table 10 in real time during the laser processing process.

The device control unit 70 controls each mechanism that drives the laser processing device 1. The device control unit 70 controls each part of the laser processing device 1 and realizes laser processing by the laser processing device 1. The device control unit 70 controls the movement unit 30 (X-axis movement unit 31 and Y-axis movement unit 32) according to the planned machining shape input and set by the operator, and moves the chuck table 10 and the laser beam irradiation unit 20 relative to each other. By moving the laser beam in the X-axis direction or the Y-axis direction, laser processing of the workpiece 100 along the shape to be processed is realized.

The device control unit 70 includes a computer system. The device control unit 70 includes an arithmetic processing device having a microprocessor such as a CPU (central processing unit), a storage device having a memory such as ROM or RAM, and an input/output interface device. The arithmetic processing device executes arithmetic processing according to a computer program stored in the storage device, and sends control signals for controlling the laser processing device 1 to each component of the laser processing device 1 via the input/output interface device. Output to. The functions of the device control section 70 are realized by the arithmetic processing device executing a computer program stored in a storage device.

The operation of the laser processing apparatus 1 according to the first embodiment having the above configuration will be described below. The laser processing apparatus 1 moves the chuck table 10 and the laser beam irradiation unit 20 relatively along the shape to be processed by the moving unit 30 controlled by the apparatus control unit 70, and moves the chuck table 10 and the laser beam irradiation unit 20 by the laser beam irradiation unit 20. A shield tunnel is formed in the workpiece 100 along the shape to be processed by irradiating the workpiece 100 held by the workpiece 10 with the laser beam 25 to perform laser processing.

In the laser processing apparatus 1, while the movement unit 30 is moving the chuck table 10 and the laser beam irradiation unit 20 relatively along the shape to be processed, the calculation unit 50 continuously or every minute time, A deviation, which is the amount of deviation between the actual coordinate position of the chuck table 10 and the coordinate position stored in the storage unit 40, is calculated. The laser processing device 1 uses the laser beam scanning unit 23 controlled by the control unit 60 to change the traveling direction of the laser beam 25 so as to cancel out the deviation calculated by the calculation unit 50, thereby minimizing the deviation due to the axis operation. A correction is made to bring the irradiation position of the laser beam 25 on the workpiece 100 on the chuck table 10 as close as possible to a position along the shape to be processed. In the laser processing apparatus 1, the laser beam scanning unit 23 controlled by the control unit 60 causes the scanning mirror 234 to resonate around the axis of the shaft 232, so that the workpiece on the chuck table 10 can be moved with higher precision. The irradiation position of the laser beam 25 at 100 can be corrected.

Each time the calculation unit 50 calculates the deviation, the laser processing apparatus 1 changes the traveling direction of the laser beam 25 using the laser beam scanning unit 23, and limits the irradiation position of the laser beam 25 to a position along the shape to be processed. Make corrections to bring it closer. In the laser processing apparatus 1, while the moving unit 30 moves the chuck table 10 and the laser beam irradiation unit 20 relatively along the shape to be processed, the calculation unit 50 calculates the deviation, and the laser beam scanning unit 23 The correction of the irradiation position of the laser beam 25 is repeated continuously or at minute intervals.

Next, an example and a conventional example will be described. In the example, the laser processing apparatus 1 according to the embodiment includes a calculation unit 50 that calculates the deviation, and a control unit 60 that controls the laser beam scanning unit 23 and changes the traveling direction of the laser beam 25 so as to cancel the deviation. Using this, the shape to be machined is set as a circular shape with a diameter of 10 mm, and the disc-shaped workpiece 100 is laser-processed along the shape to be machined to form a shield tunnel, and the actual laser beam at that time is The trajectories of 25 irradiation positions were detected. The conventional example differs from the embodiment in that a laser processing apparatus that does not include the calculation unit 50 and the control unit 60 is used, and the trajectory of the actual irradiation position of the laser beam 25 is otherwise similar to the embodiment. Detected.

FIG. 4 is a diagram illustrating the effects of the laser processing apparatus 1 according to the embodiment. In addition, in FIG. 4, the deviation amount, which is the amount of deviation from the circular shape with a diameter of 10 mm, which is the planned shape to be processed, is shown enlarged by 1000 times. A curve 301 shown as a solid line in FIG. 4 shows the locus of the actual irradiation position of the laser beam 25 in the example. A curve 302 shown by a broken line in FIG. 4 shows the locus of the actual irradiation position of the laser beam 25 in the conventional example.

As shown in FIG. 4, a curve 301 showing the locus of the actual irradiation position of the laser beam 25 in the example generally overlaps with a circle with a diameter of 10 mm showing the shape to be processed. That is, it can be seen that in the example, laser processing could be realized with high accuracy along the shape to be processed. On the other hand, the curve 302 showing the trajectory of the actual irradiation position of the laser beam 25 in the conventional example has a deviation of about several μm from a circle with a diameter of 10 mm showing the shape to be processed. The curve 302 has a particularly large deviation in the X-axis direction or the Y-axis direction. That is, it can be seen that in the conventional example, laser processing was realized with a deviation of approximately several μm along the shape to be processed.

In the laser processing apparatus 1 according to the embodiment having the above configuration, the calculation unit 50 calculates the actual coordinate position of the moving unit 30 and the coordinates of the planned processing shape when the moving unit 30 is moved in the planned processing shape. A deviation, which is the amount of deviation from the position, is calculated, and the control unit 60 controls the laser beam scanning unit 23 to change the traveling direction of the laser beam 25 so as to cancel the deviation calculated by the calculation unit 50. Therefore, the laser processing apparatus 1 according to the first embodiment has the effect of making the deviation due to the axis movement as close to zero as possible, realizing highly accurate processing, and improving the accuracy of the processed shape of the workpiece 100. be effective. In particular, when the NA of the condenser 22 is as high as 0.3 or more and the interval (scan range) in which the laser beam 25 can be scanned is limited, the laser processing apparatus 1 according to the first embodiment can more effectively perform the above processing. It will demonstrate the action and effect that it has.

Further, in the laser processing apparatus 1 according to the embodiment, the laser oscillator 21 oscillates a laser beam 25 having a wavelength that is transparent to the workpiece 100, and the NA of the condenser 22 is 0.3 or more. .8 or less. For this reason, the laser processing apparatus 1 according to the embodiment can be sufficiently easily etched while sufficiently suppressing the possibility that cracks will occur in the workpiece 100 and the bending strength will decrease due to laser processing. The effect is that a shield tunnel can be formed.

Note that the present invention is not limited to the above embodiments. That is, various modifications can be made without departing from the gist of the invention.

1 Laser processing device 10 Chuck table 20 Laser beam irradiation unit 21 Laser oscillator 22 Concentrator 23 Laser beam scanning unit 25 Laser beam 30 Movement unit 40 Storage unit 50 Calculation unit 60 Control unit 100 Workpiece

Claims (3)

A laser processing device,
a chuck table that holds the workpiece;
a laser beam irradiation unit that laser-processes the workpiece held on the chuck table;
a moving unit that relatively moves the chuck table and the laser beam irradiation unit;
a memory unit that stores a planned shape to be processed, which is an area where the workpiece is to be irradiated with a laser beam, in coordinate positions;
While the moving unit is moving the chuck table relative to the laser beam irradiation unit according to the trajectory of the coordinate position of the shape to be machined stored in the storage unit , the actual coordinate position of the chuck table and the a calculation unit that calculates a deviation that is the amount of deviation from the coordinate position stored in the storage unit;
The laser beam irradiation unit is
a laser oscillator that emits a laser beam;
a condenser that condenses a laser beam emitted from the laser oscillator and irradiates the workpiece held on the chuck table;
a laser beam scanning unit disposed between the laser oscillator and the condenser and changing the traveling direction of the laser beam emitted from the laser oscillator to a desired direction;
While controlling the laser beam scanning unit and moving the chuck table with respect to the laser beam irradiation unit with the moving unit according to the trajectory of the coordinate position stored in the storage unit, the calculation unit calculates the A laser processing device further comprising a control unit that changes the traveling direction of the laser beam so as to cancel out the deviation. In the laser beam irradiation unit,
The laser oscillator emits a laser beam with a wavelength that is transparent to the workpiece,
The laser processing apparatus according to claim 1, wherein the NA of the condenser is 0.3 or more and 0.8 or less. further comprising a position detection unit that detects the position of the chuck table,
The calculation unit calculates the deviation, which is the amount of deviation, based on the actual coordinate position of the chuck table acquired from the position detection unit and the coordinate position of the planned shape of the chuck table acquired from the storage unit. Calculate,
3. The laser processing apparatus according to claim 1, wherein the control unit is a circuit board that receives the deviation directly from the calculation unit and controls the laser beam scanning unit.

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