KR100824962B1 - Apparatus and method for cutting substrate using ultrafast frequency laser - Google Patents

Abstract

An apparatus and a method for cutting a substrate are provided to cut the substrate having an indium tin oxide layer or an indium zinc oxide layer by using an optical system capable of adjusting a DOF(Depth of Focus). An apparatus for cutting a substrate by using a laser beam comprises a laser generator(21) for generating an ultra high frequency laser, an optical system(23) capable of adjusting the DOF of the laser beam, mirrors(22,25) for adjusting an optical path such that the laser generated from the laser generator is guided into the optical system, and a focus adjusting device(24) for adjusting the focus of the laser beam. The laser beam generated from the laser generator is split by a beam splitter. A scan driver is provided to change the optical path of the laser beam.

Description

Apparatus and method for cutting substrate using ultrafast frequency laser}

1 is a block diagram of a device for cutting a glass substrate according to the prior art

2 is a block diagram showing an embodiment of the present invention

3 is a view showing an embodiment in which the DOF is adjusted according to the thickness of the substrate according to an embodiment according to the present invention;

4 is a configuration diagram showing a plurality of light sources according to an embodiment of the present invention.

5 is a configuration diagram showing a cutting method in the direction of the X-axis or Y-axis according to an embodiment of the present invention

6 is a configuration diagram of replacing the optical system according to the thickness of the substrate as an embodiment of the present invention

7 is a configuration diagram for replacing the optical system according to the cut portion of the bonded substrate as an embodiment of the present invention

8 is a configuration diagram for cutting by moving a gantry or a stage according to an embodiment of the present invention

9 is a diagram illustrating a method of cutting a substrate by adjusting a focal length using an optical system according to an embodiment of the present invention.

10 is a view showing a method for monitoring the cutting of the substrate in real time by installing the monitoring device 102 as an embodiment of the present invention

11 is a view showing a method of performing a process using two stages as an embodiment of the present invention.

The present invention relates to a method for cutting a metal, non-metal or resin substrate, and more particularly, to a cutting device and a method for cutting a substrate using a microwave laser.

Instead of the conventional CRT, flat panel displays are widely used. Currently, flat panel displays produced or developed include liquid crystal displays (LCDs), field emission displays (FEDs), plasma displays, and PDPs. ).

The flat panel display as described above is generally manufactured through a process of cutting and separating substrates formed in a matrix form on a brittle substrate in units of cells.

As shown in Fig. 1, a horizontally rotatable table 11 for fixing the mounted substrate G by vacuum suction means and the table 11 in the Y direction (perpendicular to the ground). And a pair of parallel guide rails 12 pivotally pivotally movable and a ball screw for moving the table 11 along the guide rails 12. (13), a guide bar (14) hypothesized above the table (11) along the X direction (left and right directions), and sliding to the guide bar 14 in the X direction (sliding) A scribe head 15 that can be installed, a motor 16 that slides the scribe head 15, and a lowering movement of the scribe head 15 are possible. And a tip holder 17 installed to rotate at the same time, and a screw rotatably mounted to the bottom of the tip holder 17. It is comprised including the living wheel 1.

Therefore, the substrate cutting method according to the prior art forms a crack of a predetermined depth on the substrate to be cut by the rotation of the scribing wheel 1, and then transfers the result to a brake device to the substrate surface with a break bar. The substrate is cut by pressing along cracks formed at a predetermined depth.

However, according to the prior art, since the cutting force is applied by physical force, the cutting plane of the substrate is not constant, resulting in loss in the production of the product due to wheel replacement due to clipping phenomenon and wear, and the degradation of the quality due to the progressive crack. Cause. It can also cause particles to occur in clean rooms.

There is a method of cutting using an industrial laser such as a CO ₂ laser, but this method also heats the portion to be cut with the primary laser beam, forms a crack by cooling and then cuts it with the secondary laser beam. Since the process is complicated, the substrate suffers heat loss due to the heat transfer of the CO ₂ laser, so there is a problem that the quality is poor.

In order to solve the above problems, a method of cutting a substrate using a microwave laser has been known in recent years, but there are still difficulties in mass production since no specific process has been proposed.

In addition, according to the conventional laser cutting device, if the cutting is not made completely due to the error of the cutting device, it must be cut by manually operating the device. Therefore, this operation takes a lot of time, there is a problem that causes a lot of problems in mass production because the equipment is in a stopped state when there is no operator.

An object of the present invention is to provide an apparatus for cutting a substrate using a microwave laser, to solve the above problems.

In the present invention, an indium tin oxide film (ITO) or an indium zinc oxide film (hereinafter referred to as IZO), which is a transparent conductive film formed in a fine pattern using a microwave laser, is formed. It is an object of the present invention to provide an apparatus capable of cutting a substrate at a time regardless of the thickness of the substrate, such as a substrate or a bonded substrate.

In addition, an object of the present invention is to provide an apparatus for cutting a substrate using an optical system that can adjust the depth of focus (DOF) according to the thickness of the substrate.

In addition, an object of the present invention is to provide a variety of systems that can improve the productivity by the method of automatically adjusting the focus, using a plurality of microwave lasers, or using a multi-scan method.

In addition, an object of the present invention is to cut the substrate by continuously irradiating a laser beam to the substrate by adjusting the focal length when the output of the microwave laser is low or the DOF is less than the thickness of the substrate to be cut.

In addition, an object of the present invention is to attach the inspection device to the back of the optical system to monitor whether the cutting is made in real time after cutting if not cut after cutting in real time.

In order to achieve the above object, the present invention is a device for cutting a substrate using a laser beam, Laser oscillator for oscillating microwave laser; An optical system capable of adjusting a depth of focus of the beam; And a mirror that adjusts an optical path so that the beam oscillated by the laser oscillator can be irradiated to the optical system.

In addition, the present invention is characterized in that it further comprises a focus adjusting means for adjusting the focus when the focus of the laser beam is blurred.

In addition, the present invention provides a method for cutting a substrate using a laser beam, the method comprising: aligning a substrate to be cut on a stage and generating a microwave laser; Determining a depth of focus (DOF) of the laser beam according to the thickness of the substrate; And cutting the substrate by irradiating a portion to cut the laser beam.

In addition, after the step of determining the DOF, after splitting the laser beam into a plurality of, characterized in that it further comprises the step of adjusting the beam path to the left and right (X axis) or up and down (Y axis).

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

2 is a block diagram showing an apparatus and method for cutting a substrate using a microwave laser according to an embodiment of the present invention.

The ultrafast laser may be a laser having a very short pulse period and may include a femtosecond laser or an atosecond laser.

The substrate is a concept including all metal, non-metal, or resin substrate, glass (bare glass, ITO / IZO coated glass, bonded glass), flat panel display elements (LCD, PDP, OLED, PLED, SED used for flat panel display) ), Semiconductor materials and devices (wafers, flashes, DRAMs), PCBs, FPCB substrates and resin substrates, and various types of substrates such as optical films (polarizer films, retardation films, optical components).

As shown in FIG. 2, an optical system 23 for determining a laser oscillator 21, a first reflection mirror 22, a depth of focus (hereinafter referred to as DOF), and adjusting a focal length, and a focus adjusting means 24. ), A second reflecting mirror 25, a monitoring means 26 and a substrate 27. Reference numeral 28 denotes a DOF formed on the substrate. The optical system 23 may be referred to as an xyz optical system because both the focal length and the focal length may be adjusted. For convenience, the optical system 23 is hereinafter referred to.

Looking at the process of cutting the substrate as follows.

The microwave laser is oscillated in the laser oscillator 21 and irradiated to the substrate 27 through the first reflecting mirror 22 and the optical system 23, and the substrate 27 is cut. By cutting the substrate, the first reflecting mirror 22 and the optical system 23 are mounted on the gantry to move the gantry (not shown), or the stage (not shown) on which the substrate 27 is placed is moved. Is cut. The gantry and the stage may move simultaneously. Details will be described later with reference to FIG. 8.

When cutting, the focus may be blurred as the substrate 27 is moved. The focus is automatically adjusted by the focus adjusting means 24 and the cutting means 26 is accurately cut to the desired cutting area by the monitoring means 26. Check in real time. As the monitoring means 26, a CCD camera is generally used. The focus adjusting means 24 is a device that checks and adjusts a focus by receiving a reflected light by irradiating a test pattern onto a substrate.

In addition, although the first reflective mirror 22 for adjusting the optical path and the optical system 23 for adjusting the DOF are separated and illustrated in the present embodiment, they may be formed integrally.

The optical system 23 includes means for adjusting the DOF. The optical system 23 pre-designs the DOF to be larger than the object thickness in consideration of the thickness of the object to be processed and adjusts the beam to be focused near the center of the object. Since the technique of adjusting the DOF or adjusting the focal length like the optical system 23 is a known technique, a detailed description of the optical system 23 will be omitted.

In the present invention, the substrate can be cut by only one irradiation by using the optical system to make the DOF larger than the object thickness. In addition, the ITO / IZO film is formed instead of a single substrate, and even though the thickness of the substrate is changed, it is possible to cut a single circuit by adjusting the DOF. Similarly, a bonded substrate in which a thin film transistor (TFT) substrate and a color filter substrate are combined can also be completely cut.

3 is a view showing an embodiment in which the DOF is adjusted according to the thickness of the substrate. (A) of FIG. 3 is DOF when it is a general board | substrate, and (b) is DOF when it is a bonding board | substrate. Reference numeral 37a in FIG. 3 denotes a single substrate, and 37b denotes a bonded substrate. As can be seen from the figure, in (a) the substrate thickness is T1 and in (b) the thickness of the substrate is T2. T1 and T2 may be any thickness, and even if the thickness varies, it is possible to adjust the optical system 33 to adjust the DOF suitable for cutting the substrate.

As an embodiment of the present invention, the femtosecond laser is briefly described, and the femtosecond laser has a short pulse width (about 150 fs) and a high peak output per pulse, thereby generating no thermal expansion and shock waves around the cut portion when cutting the substrate 27. I'm not letting you.

In addition, the femtosecond laser amplified by the condenser lens has a peak power of terawatt (Tera Watt), which is much higher than that of the laser.

It can be called T3 Laser (Table Top Terawatt Laser), and the light density can be made very high just by condensing with the lens, which instantly turns the material placed near the focal point into a high temperature plasma state.

In addition, since plasma generated by a general laser works with the laser itself to absorb the laser or heat the material, it causes various phenomena such as expansion of thermal effects, instability of processing, and deterioration of efficiency.

However, in the case of microwave lasers such as femtosecond lasers, the circumstances around this change.

Usually the acceptor accepts the energy of the laser on the material side is the electron. Metals and the like are free electrons in the conduction band or electrons excited by the conduction band by light. This electron (electromagnetic field) receives energy by the oscillating electric field of the laser, which collides with atoms or ions (lattice systems) in the lattice, giving kinetic energy (because the temperature rises), causing the state of matter to change (dissolve and evaporate) As a result).

Since the time it takes for the energy to move from the electromagnetic field to the lattice system is in femtoseconds or attoseconds, the microwave energy absorption and subsequent material change (processing) are separated in time in microwave laser processing.

For example, it is expected that the plasma will not interact with the laser because the time scale at which the atoms constituting the irradiated material are ionized and the plasma occurs is longer than the pulse width. In addition, since the pulse width is shorter than the time when heat diffuses around the irradiation part, the energy of the laser is locally present in the irradiation area, causing a change of state of the material only in that area.

Therefore, in the present invention, when the substrate is cut by using the microwave laser, the cutting area to be cut does not have a heat affected zone. Therefore, the cut surface can be cut smoothly. Of course, the same effect can be obtained when using an Atosecond laser.

4 is a diagram illustrating an example of cutting a substrate using a plurality of microwave lasers. When using a plurality of lasers there is an advantage that the production time is shortened.

FIG. 5 is a view showing a method of simultaneously cutting an X axis and a Y axis using a scan driving device according to another embodiment of the present invention. Portions that overlap with the above embodiment are omitted in the drawings for simplicity of explanation and only features of the present embodiment are shown.

The laser beam oscillated by the laser oscillator 51 is reflected through the optical system 52, and the scan driver 53 may adjust the beam angle by adjusting the angle of the beam to the X axis or the Y axis. As shown in the drawing, the beam may be split into several pieces using an optical system, and the substrate may be cut using a plurality of scan driving devices. By using a plurality of optical systems 52 to function as a beam splitter, it is possible to cut a substrate by cutting the beam into several. That is, as shown in the figure, the plurality of optical systems 52 serves as a beam splitter for dividing the beam.

FIG. 5A illustrates an example of cutting along the X axis, and FIG. 5B illustrates an example of cutting along the Y axis. As shown in the drawing, the beam may be split using the optical system 52 serving as the beam splitter, and the beam path may be changed to the X axis or the Y axis using the scan driver 53. Reference numeral 58 denotes a cut line cut along the X axis, and 59 denotes a cut line cut along the Y axis.

When the X-axis cutting line 58 and the Y-axis cutting line 59 meet, they are cut into square-shaped cells. As shown in the figure, it is possible to divide the laser beam into several branches using an optical system serving as a beam splitter, and several cells can be cut in one process. (c) shows that the substrate 57 is cut into a cell shape as described above. In the present invention, such cutting is referred to as surface cutting for convenience. Each cell generated by the above-described surface cutting may be a panel of the display device. It can produce not only large LCD TVs but also panels used for small display devices such as mobile phones. That is, by using the optical system 52 and the scan driving device 53, which acts as a beam splitter, surface cutting can be performed in one step and the process time can be shortened significantly.

6 illustrates an embodiment in which DOF can be changed according to a thickness of a substrate using a plurality of optical systems. For example, suppose optical system 1 produces a DOF suitable for cutting a substrate having a thickness of T1 and optical system 2 generates a DOF suitable for cutting a substrate having a thickness of T2. When cutting the T2 substrate using the optical system 1 as shown on the left side, the substrate is cut using the optical system 2 as shown on the right side of FIG. The degree of thickness can be varied.

FIG. 7 is a diagram illustrating a system for cutting a substrate using a plurality of optical systems as in FIG. 6, and illustrates a case of cutting an LCD panel. In the case of the LCD panel, the TFT substrate 77 and the color filter substrate 78 are bonded together to complete one panel. After the TFT substrate 77 and the color filter substrate 78 are bonded together, the edge portion of the color filter substrate 78 is cut and cut to cut the edge portion in order to connect FPC (Flexible Printed Circuits) to the cut portion. will be.

FIG. 7A illustrates a case where the TFT substrate 77 is below, and FIG. 7B illustrates a case where the TFT substrate 77 is above. Although the positions of the TFT substrate 77 and the color filter substrate 78 are different in the substrates shown in the figures (a) and (b), the same DOF is generated because the thickness of the color filter substrate 78 to be cut is the same. Only the color filter substrate 78 can be cut using an optical system. In the drawings, the dotted line indicates the cut portion.

8 is a view showing a cutting method by moving a gantry 84 (gantry) in the Y-axis direction and moving the stage 87 in the X-axis direction as another embodiment of the present invention.

As shown in the figure, the present invention according to the present embodiment is a laser oscillator 81, a reflection mirror 82 reflecting a laser beam, an optical system 83 reflecting the laser beam and adjusting the DOF, gantry 84 ), The substrate 86 and the stage 87 on which the substrate 86 is placed. The laser beam oscillated by the laser oscillator 81 is reflected by the reflecting mirror 82 and is incident on the optical system 83, and the optical system 83 adjusts the optical path so that the incident beam is incident on the substrate and at the same time the DOF is generated. The laser beam is adjusted onto the substrate 86 by adjusting. The beam irradiated onto the substrate cuts the substrate 86. In this case, the gantry 84 may be moved in the vertical direction to cut in the Y-axis direction, and the stage 87 may be moved in the left-right direction to cut the substrate 86 in the X-axis direction. In the drawing, reference numeral 88 denotes an X-axis cutting line and reference numeral 89 denotes a Y-axis cutting line.

The laser oscillator 81, the reflection mirror 82, and the optical system 83 can be changed to various positions. In particular, the optical system 83 may include a reflecting mirror for adjusting the light path or may be formed as a separate device by separating the reflecting mirror. In FIG. 8, one reflective mirror 82 is formed separately from the optical system, and another reflective mirror (not shown) is integrally formed with the optical system 83. The number and position of the reflecting mirrors for adjusting the optical path can be variously changed as necessary.

9 is a diagram illustrating an example in which a substrate is cut by adjusting a focal length using the optical system 93.

According to the above embodiment, the substrate may be cut at once by adjusting the DOF to be thicker than the thickness of the substrate using an optical system. However, if the laser beam cannot be cut at a time because the DOF is not thicker than the thickness of the substrate due to low output or unexpected circumstances, the substrate can be cut by adjusting the focal length and continuously irradiating the microwave laser.

9A is a diagram showing that the optical system 93 adjusts the X-axis direction of the laser beam 94. Reference numeral 95 denotes a range on which the laser beam 94 is irradiated on the X axis, and reference numeral 96 denotes an angle at which the laser beam is irradiated. That is, the laser beam is irradiated within a predetermined range in accordance with the optical system 93.

9B shows a change range in the Y-axis direction, and (c) shows a change range in the Z-axis direction.

9 (d) illustrates a process of cutting a substrate by adjusting a focal length in the Z-axis direction. First, the focus position is aligned with the upper end of the substrate by using an optical system, and then the beam is irradiated. Finally, cutting the substrate is completed by adjusting the focal position to the bottom of the substrate and then irradiating the beam to cut the bottom. In the above embodiment, an example of changing the focal length twice and irradiating the laser beam three times is illustrated, but the focal length and the number of irradiation of the laser beam may be variously changed. In some cases, the survey can be conducted twice only by dividing it into the top and bottom.

That is, it is possible to cut the substrate at once by making the DOF thicker than the thickness of the substrate using the optical system 93. However, when the substrate cannot be cut at once due to various reasons such as poor control of the Y-axis direction, The substrate can be cut by continuously and continuously cutting the substrate by adjusting the distance of the DOF in the Z-axis direction.

Although the substrate is cut in two or three times without irradiating the laser beam at once, the microwave cutting and the focal length change speed of the microwave laser are very fast and do not affect the overall cutting speed.

In the case of cutting in two or more steps, it is advantageous in terms of device manufacturing cost since microwave lasers having a lower power than those of cutting at once can be used.

FIG. 10 is a view showing that the monitoring device 103 is installed on the rear surface of the optical system 102 to check whether the substrate is properly cut. The rest of the configuration is not shown because it is the same except for adding the monitoring device with the remaining embodiments.

The process of real-time monitoring is as follows.

The laser beam 104 passing through the optical system 102 cuts the substrate 106 and a cutting line 105 is formed. The monitoring device 103 observes the cut line 105 to see whether the cut is complete. This is to prevent the error that the substrate is not cut because of the oscillation of the laser beam in the laser oscillator. The optical system 102 and the monitoring device 103 may be made into one module. In the present embodiment, the cutting head unit 101 is referred to for convenience.

Check the cutting in real time and if the cutting is not complete, immediately rework and cut.

The monitoring device 103 may be a laser displacement sensor or a real time camera.

11 is another embodiment of the present invention for shortening the working time required for the process. As shown in FIG. 8, since only one stage is used in the related art, a time for loading or unloading a work object into a stage is relatively longer than a work time for working on an object, and a work efficiency is lowered. However, when using two stages as in the above embodiment, the working time can be shortened.

Looking briefly at the work process, the robot 105 grasps a single substrate from a place where a work object such as a substrate is gathered, and is disposed above the first stage 101. At this time, the lift pin 103 is lifted up and the substrate is seated on the lift pin 103 by the robot 105. After the seating, the robot moves to the place where the work object is again, grips the substrate 104 and rests on the second stage 102. The work unit 106 performs the work in the order of seating on the stage. In the present invention is to perform a cutting operation using a laser beam. As the work performed in one stage is performed in two stages as described above, the time required for loading and unloading is reduced and the amount of work performed per hour increases.

As described above, according to the present invention, it is possible to cut the substrate by various methods.

According to the present invention, the substrate can be cut at once by using the microwave laser. Therefore, there is no thermal damage to the substrate, saving time and simplifying the process.

In addition, according to the present invention, it is possible to reduce the time required to cut the substrate using a plurality of microwave laser oscillator.

By adjusting the DOF through the optical system, substrates of various thicknesses can be cut at once.

In addition, according to the present invention, the substrate can be cut in the form of a cell in one step by cutting in the X axis or the Y axis by using the scan driving device.

In addition, according to the present invention, even when only a part of the substrates of the bonded substrates are cut by using a plurality of optical systems, it can be cut at once.

In addition, according to the present invention, the gantry and the stage can be moved to cut freely on the X axis or the Y axis.

According to the present invention, when the output of the microwave laser beam is low, the substrate can be cut by adjusting the focal length and continuously irradiating the laser beam.

In addition, according to the present invention, it is possible to check whether the cutting in real time by adding a real-time monitoring device behind the optical system. Therefore, it is possible to reduce the time required to check whether the cutting, and to reduce the cost.

In addition, according to the present invention, the time required for the work can be reduced by performing the work using two stages.

Claims (22)

An apparatus for cutting a substrate using a laser beam, A laser oscillator for oscillating microwave laser; An optical system capable of adjusting a depth of focus (DOF) of the laser beam; A mirror for adjusting an optical path so that the beam oscillated by the laser oscillator can be irradiated to the optical system; And And focusing means for adjusting focus when the focus of the laser beam is blurred. delete The apparatus of claim 1, further comprising a beam splitter for dividing the beam oscillated by the laser oscillator, and a scan driving device for changing an optical path such that the beam emitted from the beam splitter is emitted in the X axis or the Y axis. Substrate cutting device. delete The apparatus of claim 1, wherein the optical system has a DOF value greater than a thickness of a substrate to be cut. The substrate cutting apparatus according to claim 1, wherein the substrate is a single glass substrate, a bonded substrate, or a substrate on which an indium tin oxide film (ITO) or an indium zinc oxide film (IZO) is formed. The apparatus of claim 1, wherein the substrate comprises any one of a metal substrate, a nonmetal substrate, and a resin substrate. 2. The substrate according to claim 1, wherein the substrate comprises any one of a glass substrate or a flat panel display element, a semiconductor material or an element, a resin substrate or an optical film, which is a material of a PCB substrate. Substrate cutting device. The apparatus of claim 1, wherein the optical system and the mirror are integrally formed. The substrate cutting apparatus of claim 1, wherein the optical system is capable of adjusting a focal length. The apparatus of claim 1, further comprising a monitoring device configured to determine whether the substrate is cut on the rear surface of the optical system. The apparatus of claim 11, wherein the monitoring device is a laser displacement sensor or a real time camera. In the method of cutting a substrate using a laser beam, Aligning the substrate to be cut on a stage and generating a microwave laser; Determining a depth of focus (DOF) of the laser beam according to the thickness of the substrate; Cutting a substrate by irradiating a portion to cut the laser beam; And Checking whether the cutting of the substrate has been completed completely. The method of claim 13, further comprising, after determining the DOF, dividing a laser beam into a plurality of beams, and then adjusting the beam path to left and right (X axis) or up and down (Y axis). Substrate cutting method. delete The method of claim 13, wherein the cutting comprises moving and cutting a mirror capable of adjusting an incident path of a beam or a gantry equipped with an optical system capable of adjusting DOF. The method of claim 16, wherein the cutting comprises cutting the stage on which the substrate is aligned by simultaneously moving in a direction perpendicular to a moving direction of the gantry. The method of claim 13, wherein the substrate is a single glass substrate, a bonded substrate, or a substrate on which an indium tin oxide film (ITO) or an indium zinc oxide film (IZO) is formed. The method of claim 13, wherein the substrate comprises one of a metal substrate, a nonmetal substrate, and a resin substrate. 14. The substrate according to claim 13, wherein the substrate comprises any one of a glass substrate or a flat panel display element which is a material of a flat panel display, a semiconductor material or element, a resin substrate which is a material of a PCB substrate, or an optical film. Substrate cutting method. The method of claim 13, wherein determining the depth of focus determines the focal length along with the depth of focus. 18. The method of claim 17, wherein the stage comprises a plurality of stages.

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