JP2014037003A - Laser processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser processing apparatus for improving the working speed of a glass substrate.SOLUTION: A glass substrate working apparatus processes a glass substrate by irradiating the glass substrate with a laser beam. A rotary disk 6 formed of a plurality of transparent substances of different refractive indices is interposed between a capacitor lens 3 for condensing the laser beam in the glass substrate and a glass substrate 4. The laser beam emitted from the capacitor lens 3 is caused to pass through the plurality of transparent substances of different refractive indices by rotating the rotary disk 6, so that the focal point of the inside of a workpiece 4 is modulated in the optical axis direction from the deep side to the incident beam side thereby to retain the transpiration path of the gas generated in the work piece 4. After processed, the laser beam is moved to a next position.

Description

Detailed Description of the Invention

  The present invention relates to a laser processing apparatus, and more particularly to a laser processing apparatus that performs processing by irradiating a glass substrate with laser light.

  As a glass substrate processing apparatus using laser light, for example, an apparatus disclosed in Patent Document 1 is known. In this type of processing apparatus, an object to be processed such as a glass substrate is irradiated with green laser light having a wavelength of about 532 nm. The green laser light is generally transmitted through the glass substrate, but when the laser light is collected and the intensity exceeds a certain threshold value, the glass substrate absorbs the laser light. In such a state, plasma is generated in the condensing part of the laser beam, and thereby the glass substrate is evaporated. Processing such as forming a hole in the glass substrate can be performed using the principle described above.

  Patent Document 2 discloses a laser processing apparatus for rotating and scanning a plurality of condensing points on the surface of an object to be processed and moving the laser light in the optical axis direction.

JP 2007-118054 A JP 2011-11212 A

  For example, when forming a hole in a glass substrate using the conventional laser beam processing apparatus as described above, the laser beam is scanned along the circumference (processing line) of the hole, and the inside of the processing line is removed. As a result, a hole is formed. At that time, the mechanism as shown in Patent Document 2 is used to perform processing while rotating the laser beam, and the condensing point is moved in the optical axis direction to facilitate the processing.

  However, the conventional method for processing a glass substrate using a laser beam has the disadvantage that the apparatus itself is expensive in addition to the problem that it takes a long processing time. Therefore, shortening of processing time and cost reduction of the apparatus are desired.

  An object of the present invention is to shorten the processing time in laser processing.

  Another object of the present invention is to provide a laser processing apparatus that can be realized with an inexpensive configuration.

  A laser processing apparatus according to the present invention includes a work table on which an object to be processed is placed, a laser light output unit that outputs laser light, and a condensing light that condenses the input laser light at one point inside the object to be processed. A condensing portion comprising a lens, and a modulation mechanism portion that exists between the condensing lens and the surface of the object to be processed and moves the condensing point in the optical axis direction.

  In this apparatus, the optical system guides the laser light from the laser light output unit to the condenser lens and further guides it to the object to be processed. In the following description, a glass substrate may be described as an example of the workpiece. The modulation mechanism portion has a function of reciprocating the light condensing point along the optical axis direction inside the glass substrate placed on the work table. The work table moves the glass substrate in a plane perpendicular to the optical axis of the laser beam. Damage caused by the laser light is formed inside the glass substrate, and extends in the depth direction at the modulation mechanism portion. By moving the work table, it is possible to form a damaged region along the cutting line on the glass substrate.

  Here, the position of the condensing point inside the glass substrate can be moved in the optical axis direction by the modulation mechanism portion. After that, the work table moves. This is a feature of the present application. Normally, since the focal point cannot be moved instantaneously, processing is performed while keeping the depth constant, and then the work table is moved after moving the focal point in the direction of the optical axis. . Since the work table moves during the formation of the condensing points with different depth directions, if the work table movement accuracy is insufficient, the converging point will be displaced in the vertical direction, which may hinder the cutting of the glass. was there. In addition, in order to increase the processing accuracy, there was a disadvantage that the weight of the table also increased.

  Another disadvantage of the conventional processing apparatus is that after the damage is formed on the glass substrate at the laser condensing point, the time until the damage to the region different in depth only at the same position is increased. This occurs because the damage is formed again at different depths after changing the depth after forming damage at the same depth. For this reason, even if the path for transpiration of the glass is formed in the first damage formation, the transpiration path is blocked when the molten glass is solidified until the next damage formation at a different depth is performed. There was a concern that a glass transpiration path could not be secured due to damage at the condensing point.

  In this application, since the work table is moved at the same position of the work table in the optical axis direction, the work table is moved and the adjacent part is machined, the work table is moved accurately. Can be reduced. For this reason, the table can be reduced in weight, and the entire apparatus can be realized at low cost.

  In the present invention as described above, in processing of a glass substrate using laser light, processing time can be shortened as compared with the conventional case. Further, the device configuration is simplified, and the cost of the device can be suppressed.

The optical system of the glass substrate processing apparatus by one Embodiment of this invention. The figure explaining the expansion of a condensing part and a modulation mechanism part, and the position of a condensing point. The figure explaining operation | movement of a modulation mechanism part. The figure explaining the operating principle of a modulation mechanism part in detail. The figure explaining operation | movement of a modulation mechanism part. The figure explaining the operating principle of the modulation mechanism part by another embodiment in detail. The figure explaining the operation principle of the modulation mechanism part by another embodiment in detail. The figure which shows the change of the condensing point by another embodiment of a modulation mechanism part, the condition of the damage inside a glass substrate, and the path | pass of transpiration | evaporation of a glass substrate. Diagram explaining the process of forming damage inside the glass substrate The figure explaining the time change of the timing which changes a condensing point position, and the damage formation place inside a glass substrate.

[overall structure]
FIG. 1 shows the overall configuration of a glass substrate processing apparatus according to an embodiment of the present invention. This glass substrate processing apparatus is an apparatus for performing processing such as drilling by irradiating a laser beam along a processing line of a glass substrate. This apparatus includes a laser light output unit 1, a work table 5 on which a glass substrate 4 as an object to be processed is placed and moved, a condensing lens 3 for condensing laser light inside the glass substrate, and a laser. An optical system 2 for guiding laser light from the output unit 1 to the condenser lens 3 (a mirror optical system is illustrated in FIG. 1) is provided. Between the condensing lens and the glass substrate surface, a modulation mechanism portion 6 for moving the condensing point in the optical axis direction is installed. The modulation mechanism portion 6 has a function of reciprocating the condensing point along the optical axis direction inside the glass substrate 4 placed on the work table 5. By inserting a wedge prism 7 in the middle of the optical axis and applying minute vibrations to this, the direction of the laser beam can be changed minutely.
Here, as shown in FIG. 1, in the plane along the upper surface of the work table 5, the axes orthogonal to each other are defined as the x axis and the y axis, and the vertical axis orthogonal to these axes is defined as the z axis. Further, both directions along the x axis (+ direction and − direction) are defined as the x axis direction, both directions along the y axis are defined as the y axis direction, and both directions along the z axis are defined as the z axis direction.

<Worktable>
The work table 5 is formed in a rectangular shape, and a table moving mechanism (not shown) for moving the work table 5 in the x-axis direction and the y-axis direction is provided below the work table 5. .

  A plurality of air inlets (not shown) are formed in a lattice shape on the work table 5, and the glass substrate 4 disposed on the work table 5 can be sucked and fixed. The intake mechanism is constituted by a well-known exhaust pump or the like and will not be described in detail. The plurality of air inlets also serves to suck in the gas of transpiration of glass that is ejected from the back surface of the glass substrate 4 during laser processing.

  The work table 5 is movable in the x-axis direction and the y-axis direction. This movement is driven by driving means such as a well-known motor or the like (including a stepping motor). The movement of the working table 5 can also be controlled by a signal from the modulation mechanism portion 6.

<Laser light output unit>
The laser beam output unit 1 is composed of a laser tube similar to the conventional one. For example, a green laser having a wavelength of 532 nm is emitted from the laser light output unit 1, and the glass substrate 4 on the work table 5 is condensed and irradiated from the vertical direction by the optical system 2 and the condenser lens 3.

<Modulation mechanism part>
The modulation mechanism portion 6 is for moving the condensing point minutely along the optical axis direction, while the laser light emitted from the condensing lens 3 is condensed inside the glass substrate 4. Specifically, as shown in FIG. 2, a glass plate having a refractive index n and a plate thickness d is inserted. Then, it shifts to the light traveling direction side with respect to the locus of light when there is no glass plate. This shift amount Δ is expressed by the equation: Δ = d × (n−1) / n.
Further, in the glass substrate 4, when the refractive index n ′ of the glass substrate 4 that is an object to be processed is given, the shift amount Δ ′ of the condensing point in the glass substrate 4 is Δ ′ = d × n ′ × (n− 1) It is shown by the formula of / n.
Here, by periodically changing the thickness d and the refractive index n of the glass plate, the condensing point inside the glass substrate 4 can be changed in the optical axis direction. This is the configuration of the modulation mechanism portion.

<Optical system>
As shown in FIG. 1, an optical system 2 (mirror optical system in FIG. 1) is installed to guide laser light from the laser output unit 1 to the condenser lens 3. Further, as shown in FIG. 1, by inserting the wedge prism 7, the laser beam can be minutely changed (referred to as a moving mechanism portion) with respect to the optical axis. Thereby, in addition to the movement of the condensing point in the X and Y directions by the work table 5, the converging point can be moved in the minute X and Y directions.
Further, as this optical system, instead of the mirror 2, it may be guided to the condenser lens 3 by an optical fiber.

<Condensing lens>
As shown in FIG. 1, the laser beam guided from the laser output unit 1 via the optical system 2 (mirror optical system in FIG. 1) is introduced into the glass substrate 4 which is the object to be processed by the condenser lens 3. Focused. The focal point is determined by the focal length of the lens, the glass thickness of the modulation mechanism portion 6, and the refractive index. Further, as shown in FIG. 1, by inserting the wedge prism 7, the laser beam is deflected with respect to the optical axis, and the wedge prism 7 is vibrated, so that the condensing point can be changed minutely. Thereby, in addition to the movement of the condensing point in the X and Y directions by the work table 5, the converging point can be moved in the minute X and Y directions.

[Operation]
Next, the processing operation of the glass substrate with laser light will be described.

Here, the height at which the glass is removed by one processing with a laser beam is several tens of μm. Therefore, when a hole is formed in the glass substrate 4, a hole is formed even if the condensing point of the condensing lens 3 is scanned only once along the processing line, that is, an inner portion of the processing line is removed. That is generally difficult.

The operation of the glass processing apparatus of the present invention will be described with reference to FIG. FIG. 3 shows the structure of the modulation mechanism portion 6. The modulation mechanism portion 6 is composed of a rotating disk made of a plurality of glass plates having different thicknesses. In FIG. 3, the glass plates in three regions d1, d2, and d3 are formed into 120-degree fan-shaped shapes 6 ₁ , 6 ₂ , and 6 ₃ , which are combined at the apex to form a rotating disk. Here, the thickness is d3>d2> d1. The rotating disk is rotated around a fan-like apex. The light beam emerging from the condensing lens 3 passes through _one of the fan-shaped glass plate regions 6 ₁ , or 6 ₂ , or 6 ₃ having the same thickness of the rotating disk, and is condensed inside the glass substrate 4.

The operation of the glass processing apparatus of the present invention will be described in detail with reference to FIG. Of the modulation mechanism portion 6 in FIG. 4, through the either of the fan-shaped glass plate regions 6 _1, OR6 _2, OR6 _3, shows the position of the focal point inside the glass substrate 4. As described above, when the refractive index n ′ of the glass substrate 4 is assumed, the shift amount Δ ′ of the condensing point in the glass substrate 4 is expressed by the following equation: Δ ′ = di × n ′ × (n−1) / n. (I = 1 or 2 or 3). By rotating the rotating disk, the thickness changes to d1, d2, and d3, so that the condensing point changes in the optical axis direction. When the refractive index n ′ of the glass substrate and the refractive index n of the glass plate match, Δ ′ = di × (n−1), and n is usually a value of about 1.5. The amount of shift of the condensing point is about half of the thickness of the three regions of the rotating disk. In FIG. 4, the focal point can be easily reciprocated along the optical axis in the glass substrate 4 simply by rotating the rotating disk.

Next, another embodiment of the glass processing apparatus of the present invention will be described with reference to FIG. FIG. 5 shows the structure of the modulation mechanism portion 6. The modulation mechanism portion 6 is composed of a rotating disk made of a plurality of glass plates having different refractive indexes. In FIG. 5, the glass plates in the three regions of refractive index n1, n2, and n3 are formed into 120 ° fan-shaped shapes 6 ′ ₁ , 6 ′ ₂ , 6 ′ ₃ and these are combined at the apex to form a rotating disk. . Here, the refractive index is n3>n2> n1. The rotating disk is rotated around a fan-like apex. The light beam emerging from the condenser lens 3 passes through any one of the fan-shaped glass plate regions 6′or ₁ , 6 ′ ₂ or 6 ′ ₃ having the same refractive index of the rotating disk, and is condensed inside the glass substrate 4. Is done.

The operation of the glass processing apparatus of the present invention will be described in detail with reference to FIG. FIG. 6 shows the position of the condensing point inside the glass substrate 4 passing through any one of the fan-shaped glass plate regions 6′or ₁ , 6 ′ ₂ or 6 ′ _{3 in} the modulation mechanism portion 6. As described above, when the refractive index n ′ of the glass substrate 4 is assumed, the shift amount Δ ′ of the condensing point in the glass substrate 4 is expressed by the following equation: Δ ′ = d × n ′ × (ni−1) / ni. (I = 1 or 2 or 3). By rotating the rotating disk, the refractive index changes to n1, n2, and n3, so that the condensing point changes in the optical axis direction. As an example, when the refractive index n ′ = 1.5 of the glass substrate and the refractive index ni of the glass plate change to 1.4, 1.5, 1, 6, the shift amounts are 0.43d and 0.5d. 0.56d. In FIG. 6, similarly to FIG. 4, the focal point can be easily reciprocated along the optical axis in the glass substrate 4 simply by rotating the rotating disk.

FIG. 7 shows a change in the focal point by rotating the rotating disk shown in FIGS. When the refractive index changes to n1, n2, and n3, the shift amounts Δ′1, 2, and 3 are condensed at positions as shown in the figure.

FIG. 8 shows the places where damage occurs in the glass substrate 4 in each case where the rotating disk is rotated. In FIG. 8 (a), the laser light passes through the fan-shaped glass plate regions 6 _'3 with timing t1 in refractive index n3. A passing area in the fan-shaped glass plate area is indicated by a dotted circle area. 'The laser beam ₂ is, fan-shaped glass plate regions 6 with a timing t3 in refractive index n1' fan-shaped glass plate regions 6 with a timing t2, the refractive index n2 laser light passes through each _one.

  FIG. 8B shows a situation in which damage enters the inside of the glass substrate 4. At timing t1, the condensing point is on the innermost side of the glass substrate 4, and a damaged area enters a location near the back surface. Next, at the timing t2 when the rotating disk rotates 120 degrees, the condensing point moves to the surface side, and a damaged area is added. At timing t3, which is further rotated by 120 degrees, the condensing point moves further to the surface side.

  FIG. 8C is a diagram showing a path in which plasma is generated in the laser beam condensing portion and damage occurs, and the glass substrate evaporates, but a hole opens in the glass substrate and the evaporated gas goes out. At timing t1, the condensing point is on the innermost side of the glass substrate 4, and a pass can be made near the back surface. Next, at timing t2 when the rotating disk rotates 120 degrees, the path moves to the surface side inside the glass substrate, and the path extends. At a timing t3 that is further rotated by 120 degrees, the condensing point is further moved to the surface side, and the path is further extended. For this reason, the vaporized gas generated inside escapes from the back surface of the glass substrate through this path.

  What is characteristic is that the focal point moves from the back surface to the front surface at the same place (indicated by position P1 in FIG. 8) by rotating the rotating disk only once. In addition, since the movement is completed in a short time, the release of the transpiration gas generated inside is completed before the hole is closed. In addition, before the movement on the work table 5, the movement of the condensing point is completed first.

  After the movement of the condensing point in the optical axis direction at the same position is completed (timing t1 → t2 → t3), the angle of the wedge prism is changed to move to the adjacent position. The rotating disk is rotated at that position, and the focusing point is moved in the optical axis direction. This process is repeated to proceed with the cutting process. The work table 5 is moved at the timing when the wedge prism 7 is returned to the original position. This is repeated and the glass substrate 4 is processed.

  Even if the wedge prism is not used, after the movement of the condensing point in the optical axis direction is completed (timing t1⇒t2⇒t3), the work table 5 is moved to an adjacent position, and at that position, the rotating disk is moved. Is rotated once to move the condensing point in the optical axis direction. The glass substrate 4 may be processed by repeating this.

FIG. 9 is a diagram for explaining how a damaged region is formed inside the glass substrate 4 in the process of performing the above operation. The processing position moves from P1⇒P2⇒P3⇒P4⇒P5, and the damage distribution generated in the glass substrate 4 after timing t2 at P5 is shown.

FIG. 10 is a diagram showing the relationship between the machining position and time. At the position P1, the rotating disk is rotated in synchronization with the timing t1⇒t2⇒t3 to change the depth of the damage area. Next, the same sequence is performed at the position P2, and the same sequence is performed at P3 and P4, and the process is performed up to the timing t2 at P5.

Next, the conventional processing method and the present invention will be compared.

  First, in the conventional processing method, the position of the condensing lens 3 is set so that the condensing point (processing part) is formed on the lower surface of the glass substrate. In this state, after the condensing point makes one turn along the processing line, the position of the condensing lens 3 is moved in the optical axis direction to raise the condensing point. Similarly, after the condensing point makes one turn along the processing line, the condensing point is further raised. By repeatedly executing the above operation, a hole can be formed by removing the inner portion of the processing line. However, as described above, in the conventional method, it is necessary to increase the accuracy of movement of the work table, and the transpiration path is blocked when the molten glass is hardened, and the transpiration path of the glass due to damage at the internal condensing point. However, there were two problems that there were concerns that could not be secured.

  In the processing method of the present invention, the condensing point (processed part) moves from the lower surface of the glass substrate toward the upper surface by rotating the rotating disk once at each processing position of the work table. Then move to the adjacent machining position and repeat the same. For this reason, the required level of accuracy of the work table may be low. Further, since the movement of the condensing point is completed before the molten glass is hardened, there is an advantage that processing can be performed while securing a transpiration path of the glass due to damage at the internal condensing point.

[Other Embodiments]
The present invention is not limited to the above-described embodiments, and various changes or modifications can be made without departing from the scope of the present invention.

  In the above embodiment, the rotating disk is composed of three areas, but this number is not limited to this. Moreover, although demonstrated with the same angle (120 degree | times), this angle does not need to be the same. In addition, although two cases of refractive index and glass thickness have been described, there is no problem even if they are a combination of both. Moreover, although the constituent material of the rotating disk has been described with glass, it need not be glass.

  Examples of the workpiece 4 include materials such as tempered glass, silicon, sapphire, silicon carbide, gallium nitride, and low-k material in addition to the glass described in the above description.

DESCRIPTION OF SYMBOLS 1 Laser beam output part 2 Optical system 3 Condensing lens 4 Object 5 Work table 6 Modulation mechanism part 7 Wedge prism

Claims (7)

  A processing apparatus that performs processing by irradiating an object to be processed with a laser beam, a work table on which the object to be processed is placed, a laser beam output unit that outputs laser beam, and an input laser beam to be processed A condensing lens for condensing on an object, an optical system for guiding the laser beam output to the condensing lens, and between the condensing lens and the object to be processed and emitted from the condensing lens to be processed A laser processing apparatus comprising: a modulation mechanism part that moves a point that is focused on an object in the optical axis direction; and a movement mechanism part that has a function of moving a processing point in conjunction with repeated changes in the position of the focusing point.   The modulation mechanism portion is composed of a rotating disk formed of a plurality of transparent objects having different thicknesses, and the laser light emitted from the condenser lens is rotated by rotating the rotating disk. The laser processing apparatus according to claim 1, wherein the condensing point in the object to be processed is modulated in the optical axis direction by passing the light through a different transparent object.   The modulation mechanism portion is composed of a rotating disk formed of a plurality of transparent objects having different refractive indexes, and the laser light emitted from the condenser lens is rotated by rotating the rotating disk, so that a plurality of refractive indexes. The laser processing apparatus according to claim 1, wherein the condensing point in the object to be processed is modulated in the optical axis direction by passing the light through a different transparent object.   The modulation mechanism portion is composed of a rotating disk formed of a plurality of transparent objects having different refractive indexes and thicknesses, and a plurality of laser beams emitted from the condenser lens are rotated by rotating the rotating disk. The laser processing apparatus according to claim 1, wherein the condensing point in the object to be processed is modulated in the optical axis direction by passing the light through transparent objects having different refractive indexes. 5. The laser according to claim 1, wherein the moving mechanism portion moves in a direction perpendicular to an optical axis of a condensing point by movement of a wedge prism and a work table arranged in the optical system. Processing equipment. 5. The laser processing apparatus using laser light according to claim 1, wherein the moving mechanism part moves the light focusing point in a direction perpendicular to the optical axis on a work table. In the modulation mechanism part, at the same position of the object to be processed, the position of the condensing point is moved from the point opposite to the laser light incident side to the incident side along the optical axis, After processing while securing the transpiration path of the gas generated inside the workpiece, after sending a signal to the moving mechanism part and moving to the next position, the same processing is performed at the new position A laser processing device that moves the processing point while repeating this process.