KR101335039B1 - Laser processing apparatus, and processing method for a workpiece using the same - Google Patents

Abstract

An object of the present invention is to provide a laser processing apparatus in which the variation in machining accuracy when machining in two orthogonal directions is reduced even if the beam profile is not isotropic with respect to the advancing direction.
The laser processing apparatus includes a converting means for branching a laser beam emitted from a laser light source into a first branched light and a second branched light and a beam profile of the second branched light by 90 ° around an advancing direction; Optical path common means for commonizing the optical path of the first branched light and the second branched light passing through the conversion means to one irradiation optical path leading to the condensing lens, and the first branched light and the second branched light between the branching means and the optical path commoning means Two types of lasers having the same beam profile and orthogonal to the workpieces fixed to the stage by providing an optical system having an optional blocking means for selectively blocking the light, and switching the light blocked by the selective blocking means. Any one of the lights was made to be selectively irradiated.

Description

Processing method of workpiece using laser processing device and laser processing device {LASER PROCESSING APPARATUS, AND PROCESSING METHOD FOR A WORKPIECE USING THE SAME}

The present invention relates to a laser processing apparatus for processing a workpiece by irradiating a laser beam, and a processing method of a workpiece using the same.

Background Art A laser scribing apparatus for forming a processing groove (scribe line) by irradiating a pulsed laser light (hereinafter referred to as laser light) to a workpiece such as a semiconductor substrate is already known (see Patent Document 1, for example). In the technique disclosed in Patent Literature 1, a semiconductor substrate (LED substrate) on which a LED circuit pattern in which two-dimensionally arranged unit patterns constituting an LED is formed on a surface thereof is subjected to processing. Specifically, a scribe line for dividing the LED substrate into an LED chip is formed by irradiating while irradiating a laser beam relatively in accordance with a predetermined dividing position (called a street) set in a lattice shape according to the LED circuit pattern.

Furthermore, after splitting the laser beam emitted from the laser light source into two kinds of laser beams having different polarization states by the first polarization beam splitter, the intensity of both is individually adjusted by the half wave plate, and then the second polarized light. The laser processing apparatus which uses a beam splitter and spaces apart and irradiates both laser beams is also known (for example, refer patent document 2).

Japanese Patent Application Publication No. 2004-114075 Japanese Patent Application Publication No. 2010-284669

In the conventional laser processing apparatus disclosed in Patent Document 1, when a scribe line is formed in a lattice shape, the laser light is scanned in two orthogonal directions. This is, for example, irradiation of a laser beam according to a processing scheduled position while moving the stage in the XY angular direction while the LED substrate is fixed on the XY stage movable in the XY biaxial direction so that the street coincides with the moving direction of the stage. It is realized by doing

At this time, from the viewpoint of the quality stability of the LED, it is preferable that the scribe lines are formed with the same processing accuracy in both the XY directions, but for that purpose, the beam profile (spatial distribution of the intensity of the laser light) of the laser beam is compared with the irradiation direction. It is necessary to be isotropic or equivalent at least in both XY directions. However, in order to realize such irradiation of a laser beam, since it costs a lot, it is difficult to implement | achieve only by using a commercially available laser light source.

Alternatively, after the formation of the scribe line in one direction (first direction), the LED substrate is rotated 90 degrees in the horizontal plane to form the scribe line in the second direction orthogonal to the first direction. I think. In this case, although the equivalence of the beam profile is not required, there is a possibility that misalignment of the LED substrate may occur due to the rotation operation. Therefore, in order to ensure processing accuracy, the alignment operation is performed again after rotation to reset the irradiation position of the laser beam. There is a need. Therefore, there exists a problem that processing time is required.

Moreover, the apparatus disclosed in patent document 2 can only irradiate and irradiate two types of laser beams in one process advancing direction, and cannot suppress the dispersion | variation in the process precision by a process direction.

This invention is made | formed in view of the said subject, Comprising: Providing the laser processing apparatus which the dispersion | variation in the processing precision at the time of processing in the orthogonal two directions, even if the beam profile of a laser beam is not isotropic with respect to an irradiation direction is reduced. The purpose.

In order to solve the said subject, invention of Claim 1 is a laser processing apparatus which irradiates a laser beam, and processes a to-be-processed object, The stage part which fixes a to-be-processed object, and the laser beam radiate | emitted from the laser light source from the said condensing lens An optical system for irradiating the workpiece to be fixed to a part, wherein the optical system is configured to branch the laser light emitted from the laser light source into first and second branch lights, and the second branch. An optical path for commonizing the beam profile of the light to the converging means until it reaches the converging lens of the diverging means for rotating the beam profile of the light by 90 ° with the axis of travel as the axis; Selectively blocking the first branched light and the second branched light between a commoning means and the branching means and the optical path commoning means; Has a selective blocking means, when the first branched light passed through the optical path commoning means is a first irradiation laser beam, and the second branched light passed through the commoning means is a second irradiation laser light, By switching the first branched light and the second branched light blocking by the selective blocking means, the first irradiation laser light having the same beam profile and orthogonal to the workpiece fixed to the stage unit; It is possible to selectively irradiate any one of said 2nd irradiation laser beams.

Invention of Claim 2 is a laser processing apparatus of Claim 1, Comprising: The said stage part is movable in the 1st direction and 2nd direction orthogonal to each other, and irradiates the said to-be-processed object with the said 1st irradiation laser beam. The stage portion is moved in the first direction at the time, and the stage portion is moved in the second direction when the second irradiation laser beam is irradiated onto the workpiece.

Invention of Claim 3 is the laser processing apparatus of Claim 1 or Claim 2, Comprising: The said conversion means is comprised by combining several mirror, It is characterized by the above-mentioned.

Invention of Claim 4 is the laser processing apparatus of Claim 1 or Claim 2, Comprising: The said conversion means is comprised by the prism which has a some reflective surface, It is characterized by the above-mentioned.

Invention of Claim 5 is the processing method of the to-be-processed object using the laser processing apparatus of Claim 2, Comprising: The fixing process which fixes the said to-be-processed part, and the orthogonal process position of the grid-shaped process object set to the to-be-processed object An alignment step of matching the extension direction to the first direction and the second direction, and a machining target position that extends in the first direction by irradiating the first irradiation laser light while moving the stage part in the first direction; And a second processing step of processing a target position extending in the second direction by irradiating the second irradiation laser light while moving the stage portion in the second direction. It features.

According to the invention of Claims 1 to 4, a laser processing apparatus capable of selectively using two kinds of laser beams having beam profiles having the same shape and orthogonal directions is realized.

In particular, according to the invention of claim 2, even if the beam profile of the laser light emitted from the laser light source is not isotropic with respect to the processing direction, the laser processing apparatus in which the variation in the processing accuracy when processing in two orthogonal directions is reduced is Is realized.

According to the invention of claim 5, even if the beam profile of the laser light emitted from the laser light source itself is not isotropic, processing in two orthogonal directions can be performed with the same processing accuracy.

1 is a perspective view illustrating a configuration of a laser processing apparatus 100 according to the present embodiment.
2 is a view showing a state in which the first optical path shutter 24a is opened while the second optical path P2 is blocked by the second optical path shutter 24b.
3 is a view showing a state in which the first optical path P1 is blocked by the first optical path shutter 24a while the second optical path shutter 24b is opened.
4 is a perspective view illustrating a configuration of the beam profile conversion unit 30.
5 is a top view of the stage portion 10 in a state where the irradiation laser light LB3 is irradiated.
6 is a perspective view illustrating the beam profile conversion prism 130.

<Outline of Laser Processing Apparatus>

1 is a perspective view illustrating a configuration of a laser processing apparatus 100 according to the present embodiment. The laser processing apparatus 100 is an apparatus which performs groove processing, a punching process, etc. to a to-be-processed object by irradiating a pulsed laser beam (hereinafter, a laser beam) to a to-be-processed object. As shown in FIG. 1, the laser processing apparatus 100 mainly includes a stage unit 10 and an optical system 20. Moreover, the laser processing apparatus 100 is equipped with the control part which is not shown in figure which controls the operation | movement of each part.

The stage part 10 is a site | part where the workpiece is mounted and fixed. The stage part 10 is mainly comprised by the X stage 11, the Y stage 12, the (theta) stage 13, and the suction chuck 14. As shown in FIG.

The X stage 11 is a moving mechanism provided in the horizontal plane so that a movement to a 1st direction is possible. The Y stage 12 is a moving mechanism provided on the X stage 11 and movable in a second direction perpendicular to the first direction in a horizontal plane. The θ stage 13 is a rotating mechanism rotatable in a horizontal plane provided on the Y stage 12. The movement operation of the X stage 11 and the Y stage 12 and the rotation operation of the θ stage 13 can be realized by a known driving mechanism (not shown).

The suction chuck 14 is a table on which the workpiece is mounted and fixed on the θ stage 13. The suction chuck 14 has a plurality of suction holes (not shown) on its upper surface 14s, and underpressure is applied to the suction holes by suction means (not shown) in the state where the workpiece is loaded on the upper surface 14s. Thus, the workpiece can be fixed by adsorption.

1 and subsequent drawings, the moving direction (first direction) of the X stage 11 is made into the X axis direction, and the moving direction (second direction) of the Y stage 12 is made into the Y axis direction. And XYZ coordinate of the right hand system which makes a perpendicular direction the Z-axis direction.

In the stage part 10 which has the above structure, the X stage 11, the Y stage 12, and the (theta) stage 13 are driven in the state which fixed the to-be-processed object to the suction chuck 14, The workpiece can be horizontally moved in the XY biaxial direction and can be rotated within the horizontal plane.

The optical system 20 is a part for irradiating a laser beam with respect to the workpiece mounted and fixed to the stage part 10. The optical system 20 includes a laser light source 21, two half wave plates 22 (first half wave plate 22a, a second half wave plate 22b), and two polarizations. Beam splitter 23 (first polarization beam splitter 23a, second polarization beam splitter 23b), two optical path shutters 24 (first optical path shutter 24a, second optical path shutter 24b) And a quarter wave plate 25, a condenser lens 26, a first horizontal reflection mirror 27, a second horizontal reflection mirror 28, a vertical reflection mirror 29, and beam profile conversion. The unit 30 is mainly provided. Among these components, except for the condensing lens 26, it is arrange | positioned in the predetermined position on 20 A of mounting tables in which the upper part of the stage part 10 was provided.

The laser light source 21 emits linearly polarized laser light LB0. As the laser light source 21, various known light sources can be used. An appropriate light source may be selected and used depending on the processing purpose. Nd: YAG lasers, Nd: YVO ₄ lasers or other solid state lasers are suitable. In addition, the laser light source 21 is preferably equipped with a Q switch.

For example, when the sapphire single crystal substrate forms a scribe line at the street position of the LED substrate used as the base substrate, it is suitable to use triple harmonics (wavelength: 355 nm) of the Nd: YAG laser. In addition, in this embodiment, the LED board | substrate means the semiconductor substrate in which the LED circuit pattern which two-dimensionally arranged the unit pattern which comprises LED is formed on the surface, and the street means these LED board | substrates. It is the division planned position when dividing (individualizing) into individual LED chips.

The polarization direction of the laser light LB0 emitted from the laser light source 21 is appropriately adjusted by the first 1/2 wave plate 22a provided on the optical path P0.

The laser beam LB0 passing through the first 1/2 wave plate 22a reaches the first polarizing beam splitter 23a provided on the optical path P0. In the first polarizing beam splitter 23a, the laser light LB0 is split into a first branched light LB1 traveling through the first optical path P1 and a second branched light LB2 traveling through the second optical path P2. . In other words, the first polarization beam splitter 23a functions as a branching means for branching the laser light LB0 into the first branched light LB1 and the second branched light LB2.

More specifically, the first polarized beam splitter 23a emits the first branched light LB1 as P-polarized transmitted light and the second branched light LB2 as S-polarized reflected light. In the case shown in FIG. 1, the 1st branch which the laser beam LB0 radiate | emitted from the laser light source 21 to the negative Y-axis direction permeate | transmits the 1st polarizing beam splitter 23a as it is toward the negative Y-axis direction The light LB1 is branched into the second branched light LB2 reflected by the first polarization beam splitter 23a in the positive X-axis direction. As the first polarizing beam splitter 23a, a transmission efficiency of 90% to 95% and a reflection efficiency of about 99% are used. Thereby, the optical loss in the 1st polarizing beam splitter 23a is reduced to a minimum.

On the 1st optical path P1, the 1st horizontal reflection mirror 27, the 1st optical path shutter 24a, and the 2nd 1/2 wave plate 22b are provided. On the other hand, on the second optical path P2, the beam profile conversion unit 30, the second horizontal reflection mirror 28, and the second optical path shutter 24b are provided.

When the first optical path P1 is not blocked by the first optical path shutter 24a (when the first optical path P1 is in the released state), the first branched light LB1 is driven by the first horizontal reflection mirror 27. After reflection, the advancing direction in a horizontal plane is changed suitably, and passes through the position of the 1st optical path shutter 24a, and reaches the 2nd 1/2 wave plate 22b. By passing through the 2nd 1/2 wave plate 22b, the 1st branch light LB1 which was P polarization becomes S polarization. The first branched light LB1 made of S-polarized light reaches the second polarized beam splitter 23b. On the other hand, when the first optical path P1 is blocked by the first optical path shutter 24a, the first branched light LB1 that has reached the first optical path shutter 24a is not shown by the first optical path shutter 24a. Is reflected toward the beam diffuser, and does not reach the second polarizing beam splitter 23b.

Further, when the second optical path P2 is not blocked by the second optical path shutter 24b (when the second optical path P2 is in the released state), the second branched light LB2 causes the beam profile conversion unit 30 to stop. After the beam profile is changed by roughness, the direction of travel in the horizontal plane is appropriately changed by being reflected by the second horizontal reflection mirror 28, and then the second polarizing beam splitter 23b is reached. The 2nd branch light LB2 which reached this 2nd polarizing beam splitter changes the polarization direction also through the beam profile conversion unit 30, and is changing from S polarization to P polarization. On the other hand, when the second optical path P2 is blocked by the second optical path shutter 24b, the second branched light LB2 reaching the second optical path shutter 24b is not shown by the second optical path shutter 24b. Is reflected toward the beam diffuser, and does not reach the second polarizing beam splitter 23b. In addition, in this embodiment, a beam profile means the spatial distribution of the intensity | strength of the laser beam which makes an axis the advancing direction (optical path direction). For convenience, the beam profile can be taken as the intensity distribution in any cross section perpendicular to the advancing direction of the laser light.

In FIG. 1, the case where four first horizontal reflection mirrors 27 and one second horizontal reflection mirror 28 are provided is illustrated, but the first horizontal reflection mirror 27 and the second horizontal reflection mirror ( The number of 28 is not limited to this, and may be provided at an appropriate number and arrangement position in accordance with a request or the like on the arrangement layout of each element constituting the optical system 20.

In addition, although FIG. 1 shows the state in which both were opened for the convenience of description, blocking of the 1st optical path P1 by the 1st optical path shutter 24a, and of the 2nd optical path P2 by the 2nd optical path shutter 24b. Blocking is done exclusively. Therefore, when one side is in the blocking state, the other side is always in the released state.

2 is a view showing a state in which the first optical path shutter 24a is opened while the second optical path P2 is blocked by the second optical path shutter 24b. 3 is a diagram showing a state in which the first optical path P1 is blocked by the first optical path shutter 24a while the second optical path shutter 24b is opened. In the case shown in FIG. 2, only the first branched light LB1 reaches the second polarized beam splitter 23b and proceeds further thereto, and in the case shown in FIG. 3, the second branched light LB2. Only the second polarizing beam splitter 23b reaches and proceeds further ahead.

More specifically, the second polarizing beam splitter 23b emits the first branched light LB1 as the reflected light toward the third optical path P3, and sets the third optical path P3 as the transmitted light. Exit toward. In other words, the second polarization beam splitter 23b functions as an optical path common means for commonizing the optical paths of the first branched light LB1 and the second branched light LB2.

In the case shown in FIGS. 1 to 3, the first branched light LB1 incident on the second polarization beam splitter 23b by going straight in the Y-axis negative direction is controlled by the second polarization beam splitter 23b. The second branched light LB2 reflected in the negative direction and going straight in the negative X-axis direction and incident on the second polarizing beam splitter 23b is transmitted through the negative X-axis direction. As the second polarization beam splitter 23b, a transmission efficiency of 90% to 95% and a reflection efficiency of about 99% are used. As a result, the optical loss in the second polarization beam splitter 23b is reduced to a minimum.

Subsequently, the first branched light LB1 reflected by the second polarized beam splitter 23b is referred to as a first irradiation laser light LB3a, and the second branched light transmitted through the second polarized beam splitter 23b ( LB2) is called 2nd irradiation laser light LB3b, and both are collectively called irradiation laser light LB3.

The irradiation laser light LB3 is circularly polarized by the quarter wave plate 25 provided on the optical path P3, and then vertically downward (Z-axis part) by the vertical reflection mirror 29 provided on the optical path P3. Direction). After the reflection, the laser beam LB3 for reflection passes through the through-hole 20B provided with the mounting table 20A, and then is collected by the condensing lens 26 on the optical path P3 and disposed directly below the through-hole 20B. After condensing, the workpiece is irradiated on the stage 10 (fixed to the suction chuck 14) while the irradiation direction is maintained in the vertical direction. More specifically, any one of the first irradiation laser light LB3a and the second irradiation laser light LB3b according to the opening / closing state of the first optical path shutter 24a and the second optical path shutter 24b. Is optionally examined. The condensing lens 26 is provided with a focusing adjustment mechanism (not shown) that can adjust the focusing state of the irradiation laser light LB3 by moving it in the Z-axis direction. By the action of such a focusing adjustment mechanism, it is possible to adjust the focusing position of the irradiation laser light LB3 to the workpiece surface, or to realize a defocus state in which the focusing position is intentionally set inside the workpiece. .

In the laser processing apparatus 100 which has a structure as mentioned above, the outline of the irradiation of the laser beam LB3 for irradiation, and the X stage 11, Y stage 12, and (theta) stage with which the stage part 10 is equipped By suitably combining the movements of (13), it is possible to process the desired machining position of the workpiece. For example, in the case of forming a scribe line on the street of the LED substrate, while moving the X stage 11 or the Y stage 12 while the extension direction of the street arranged in a lattice shape coincides with the XY biaxial direction. It is realized by irradiating the laser beam LB3 for irradiation to a street position.

Moreover, in the laser processing apparatus 100, the 1st irradiation laser beam LB3a and the 2nd irradiation laser beam are according to the opening / closing state of the 1st optical path shutter 24a and the 2nd optical path shutter 24b. Any one of (LB3b) is selectively irradiated. This point will be described in detail later.

<Relationship between Beam Profile of Laser Light and Selective Irradiation>

First, the beam profile conversion unit 30 which produces | generates the difference of the beam profile of the 1st irradiation laser beam LB3a and the 2nd irradiation laser beam LB3b is demonstrated.

In the laser processing apparatus 100 which concerns on this embodiment, the laser beam LB0 radiate | emitted from the laser light source 21 is the 1st branch light LB1 and the 2nd branch light in the 1st polarizing beam splitter 23a. Only the second branched light LB2 branching to LB2 and traveling through the second optical path P2 is configured to pass through the beam profile conversion unit 30.

4 is a perspective view illustrating the configuration of the beam profile conversion unit 30. The beam profile conversion unit 30 is a component of the laser processing apparatus 100 that converts the beam profile of the emitted laser light (output light) into something different from the beam profile of the incident laser light (incident light).

The beam profile conversion unit 30 includes a first mirror that reflects the laser light LB (incident light LBα) incident from the outside in the horizontal direction (the X-axis positive direction in FIG. 4) in the vertical direction (the Z-axis positive direction) ( 31) and a second reflecting laser beam LB reflected by the first mirror 31 in a horizontal plane and in a direction orthogonal to the direction of incidence of the first mirror 31 (the negative Y-axis in FIG. 4). By the 2nd mirror 32, the 3rd mirror 33 which reflects the laser beam LB reflected by the 2nd mirror 32 perpendicularly downward (negative direction of Z-axis), and the 3rd mirror 33 by A mirror composed of four mirrors of a fourth mirror 34 which reflects the reflected laser light LB in a horizontal plane and in a direction parallel to the reflected light from the second mirror 32 (in the Y-axis negative direction in FIG. 4). Equipped with a group. The laser light LB reflected by the fourth mirror 34 becomes the outgoing light LBβ emitted to the outside.

In addition, in the beam profile conversion unit 30 illustrated in FIG. 4, a housing 35 for storing a mirror group is provided, and an incident hole 35A in which incident light LBα from the outside is formed in the housing 35. Although the outgoing light LBβ, which is irradiated to the first mirror 31 through the light and reflected from the fourth mirror, is emitted to the outside through the exit hole 35B formed in the housing 35, the beam profile conversion unit It is not an essential form that the 30 includes the housing 35.

In the beam profile conversion unit 30 having the above-described configuration, the incident laser light LB is sequentially reflected by the mirror group so that the beam profile of the incident light LBα is rotated by 90 ° about the axis of travel. The outgoing light LBβ having the beam profile is emitted.

For example, in the case shown in FIG. 4, the beam profile of the incident light LBα has a longitudinal direction in the Y-axis direction, which is one direction in the horizontal plane, as indicated by the arrow AR1, but the beam profile of the outgoing light LBβ is the arrow AR2. As shown by, it has a longitudinal direction in a Z-axis direction. That is, the beam profile of the incident light LBα and the beam profile of the outgoing light LBβ are orthogonal when the traveling direction is taken as the axis.

In the laser processing apparatus 100, since such a beam profile conversion unit 30 is provided on the 2nd optical path P2, the beam profile of the 2nd branch light LB2 advances by the beam profile conversion unit 30 Will be rotated 90 ° around the axis. Since only the second horizontal reflection mirror 28 and the second optical path shutter 24b are provided between the beam profile conversion unit 30 and the second polarization beam splitter 23b in the second optical path P2, the beam profile conversion The beam profile of the second branched light LB2 emitted from the unit 30 in the horizontal plane is maintained until it reaches the second polarized beam splitter 23b.

On the other hand, since the first optical path P1 is provided with only the first horizontal reflection mirror 27 and the first optical path shutter 24a, the beam profile of the first branched light LB1 traveling through the first optical path P1 is the first. The polarization beam splitter 23a is maintained until it reaches the second polarization beam splitter 23b.

Therefore, also in the first branched light LB1 and the second branched light LB2 incident on the second polarization beam splitter 23b, as in the case shown in FIG. In a 90 ° rotated relationship (when rotated 90 °, the beam profile matches). This is called that both beam profiles are orthogonal or orthogonal. In addition, since the 1st branch light LB1 and the 2nd branch light LB2 originally diverged from the laser beam LB0 radiate | emitted from the same laser light source 21, both beam profiles are a direction with respect to an axial direction. Are different, but the shape itself is the same.

The optical path P3 extending from the second polarization beam splitter 23b to the stage portion 10 is provided with a quarter wave plate 25 and a vertical reflection mirror 29, and is a first set of first branched light LB1. The 2nd irradiation laser beam LB3b which is use laser beam LB3a and 2nd branch light LB2, respectively, passes through the 2nd polarizing beam splitter 23b, and is circularly polarized by the quarter wave plate 25, respectively. After that, it is reflected by the vertical reflection mirror 29. Therefore, although the advancing direction itself of the 1st irradiation laser beam LB3a and the 2nd irradiation laser beam LB3b changes, both beam profiles remain orthogonal after reflection by the vertical reflection mirror 29, have.

As described above, the first irradiating laser light LB3a and the second irradiating laser light LB3b depend on which of the first optical path shutter 24a and the second optical path shutter 24b is opened / blocked. Since the workpiece is selectively irradiated, the laser processing apparatus 100 eventually receives the first irradiation laser beam LB3a and the second irradiation laser beam in which the beam profile has the same shape and is orthogonal to each other. LB3b) can be selectively irradiated to the workpiece.

For example, FIG. 2 and FIG. 3 show the workpiece irradiated to the workpiece when the beam profile of the laser light LB0 emitted from the laser light source 21 in the Y-axis negative direction has a longitudinal direction in the X-axis direction. The difference of the beam profile of the 1st irradiation laser beam LB3a and the 2nd irradiation laser beam LB3b is shown. As shown in FIG. 2, the first irradiation laser light LB3a irradiated to the workpiece while the first optical path shutter 24a is opened and the second optical path P2 is blocked by the second optical path shutter 24b. Has a longitudinal direction in the Y-axis direction. On the other hand, as shown in FIG. 3, while the second optical path shutter 24b is opened and the first optical path P1 is blocked by the first optical path shutter 24a, the second irradiation laser light irradiated to the workpiece ( LB3b) has a longitudinal direction in the X-axis direction.

<Street processing>

As described above, the laser processing apparatus 100 capable of selectively irradiating two kinds of irradiation laser beams LB3 having an orthogonal beam profile is set in a street lattice, such as an LED substrate, that is, in a square lattice shape on the surface of the LED substrate. It is suitable for scribing in two orthogonal directions as in the case of forming a scribe line at the position of the street. This point will be described below.

FIG. 5 shows the irradiation laser light LB3 when the beam profile of the laser light LB0 emitted from the laser light source 21 has a longitudinal direction in the X-axis direction as shown in FIGS. 2 and 3. ) Is a top view of the stage portion 10 in the irradiated state. Specifically, FIG. 5A is a top view of the stage portion 10 when the first irradiation laser light LB3a is being irradiated, and FIG. 5B is a second irradiation laser light ( It is a top view of the stage part 10 when LB3b) is irradiated. However, all the illustration of the LED board | substrate which is a to-be-processed object is abbreviate | omitted. In addition, the relationship of the size of each part differs from an actual thing. In reality, the width of the street is about several tens of micrometers, and the longitudinal direction size of the beam profile of the laser beam irradiated to the LED substrate is slightly smaller than or less than the width of the street and even about several micrometers.

As shown in Fig. 5A, the first irradiation laser beam LB3a is irradiated so that the beam profile has a longitudinal direction in the Y-axis direction. On the other hand, as shown in Fig. 5B, the second irradiation laser light LB3b is irradiated so that the beam profile has a longitudinal direction in the X-axis direction. That is, both beam profiles have the same shape and are orthogonal. Therefore, the process progress direction (relative scanning direction of the 1st irradiation laser beam LB3a with respect to a to-be-processed object), and the 2nd irradiation laser beam at the time of irradiating and processing a 1st irradiation laser beam LB3a. When the processing advance direction (relative scanning direction of the 2nd irradiation laser beam LB3b with respect to a to-be-processed object) is made to be orthogonal when irradiating (LB3b), it is the same shape, when it sees about each processing advancing direction. Processing is performed by laser light having a beam profile of.

In this embodiment, a scribe line with respect to a street position is formed using this relationship. Specifically, by adjusting (aligning) the arrangement positions of the LED substrates adsorbed and fixed to the adsorption chuck 14, two extending directions perpendicular to each other of the streets arranged in a grid shape coincide with the XY both axis directions. After that, the X stage 11 is moved as shown by the arrow AR3 while irradiating the first irradiation laser beam LB3a as shown in Fig. 5A to the street position along the X-axis direction. Make a scribe line. Similarly, as shown by the arrow AR4 while irradiating the 2nd irradiation laser beam LB3b, as shown to FIG. 5 (b), the scribe with respect to the street position along the Y-axis direction by moving the Y stage 12 Make a line.

In this case, the beam profile of the first irradiation laser beam LB3a viewed along the X-axis direction and the beam profile of the second irradiation laser beam LB3b viewed along the Y-axis direction are the same. The scribe lines in the orthogonal XY two directions are formed with the same machining accuracy. In this case, since the beam profile itself of the laser light LB0 emitted from the laser light source 21 does not have to be isotropic, the above-described processing does not necessarily guarantee the isotropy of the beam profile strictly, but is a commercially available laser. Also by the laser processing apparatus 100 comprised using the light source 21, it can implement suitably.

What is necessary is just to determine the specific processing conditions in the case of performing street processing in such a form suitably in the range in which a desired scribe line is formed. For example, when the LED substrate is formed using a sapphire single crystal substrate, the wavelength of the laser light LB0 preferably falls within a wavelength range of 150 nm to 563 nm, and among them, a Nd: YAG laser is a laser light source. In the case of (21), it is preferable to use the triplex harmonic (wavelength of about 355 nm). In that case, it is preferable that the repetition frequency of a pulse is 50 Hz or more and 150 Hz or less, and it is suitable that a pulse width is 50 nsec or more and 150 nsec or less. It is suitable that peak power is 100W or more and 500W or less. Moreover, it is suitable that the moving speeds of the X stage 11 and the Y stage 12 are 100 mm / sec or more and 300 mm / sec or less.

Further, since the first irradiation laser beam LB3a and the second irradiation laser beam LB3b are circularly polarized by the quarter wave plate 25 and then irradiated to the workpiece, the state of polarization is It does not affect the processing precision.

As described above, according to the present embodiment, two types of laser beams having a stage portion movable in two directions orthogonal to each other in a state in which the workpiece is fixed by adsorption and having a beam profile having the same shape and the direction perpendicular to each other are provided. A laser processing apparatus capable of selectively used processing is realized. And according to such a laser processing apparatus, when scribing is performed in two orthogonal directions, for example, when a scribe line is formed in the street position provided in the square grid shape on the surface of an LED substrate, By matching the forming direction with the moving direction of the stage, the laser beam to be irradiated along the moving direction is determined so that the scribe lines in two orthogonal directions are the same even if the beam profile of the laser light emitted from the laser light source itself is not isotropic. It can be formed with processing precision. That is, the deviation of the processing precision of the scribe line in two orthogonal directions reduces.

<Modifications>

The beam profile conversion unit 30 according to the above-described embodiment is configured such that the incident light and the emitted light travel in the same YX plane as shown in FIG. 4, and the incident direction and the exit direction are orthogonal in the XY plane. But are not required forms. For example, in the case of the beam profile conversion unit 30 having the configuration in which the third mirror 33 and the fourth mirror 34 are omitted, the height positions of the incident light and the outgoing light are different, but both beam profiles are in a plan view. Orthogonal. Or in the case of the beam profile conversion unit 30 provided with the 5th mirror which reflects the reflected light from the 4th mirror 34 to a positive X-axis direction, an emission direction will become the same as an incident direction. That is, the configuration of the beam profile conversion unit 30 may be appropriately determined according to the arrangement position of other components such as the horizontal reflection mirror.

Moreover, in embodiment mentioned above, although the laser processing apparatus 100 demonstrated the aspect provided with the beam profile conversion unit 30 which consists of a mirror group on 2nd optical path P2, the structure of a beam profile unit is this. It is not limited to. 6 is a perspective view showing a beam profile conversion prism 130 that can be used in place of the beam profile conversion unit 30.

The beam profile conversion prism 130 includes a first reflecting surface 131, a second reflecting surface 132, a third reflecting surface 133, and a fourth reflecting surface 134 for incident light and reflected light, respectively. On the other hand, it is comprised so that it may become the same arrangement relationship as the arrangement relationship of the 1st mirror 31, the 2nd mirror 32, the 3rd mirror 33, and the 2nd mirror 34 of the beam profile conversion unit 30. FIG. Also in such a beam profile conversion prism 130, the incident laser light LB is sequentially reflected by the mirror group, so that the beam profile of the incident light LBα is rotated by 90 ° about the axis of travel. The emission light LBβ is emitted.

In the laser processing apparatus according to the above-described embodiment, although the beam profile conversion unit has rotated the direction of the profile of the second branched light LB2 by 90 °, by arranging various mirrors inside and outside the beam profile conversion unit appropriately, The laser processing apparatus provided with the beam profile conversion unit which rotates the direction of the profile of 2nd branch light LB2 by 180 degrees is also realizable. When using such a laser processing apparatus, in the reciprocating process of forming a plurality of scribe lines in parallel, it becomes possible to perform the processing in the advancing direction and the processing in the return direction with another laser light having the same beam profile. As a result, in the reciprocating process, the deviation of the machining accuracy in the reciprocating direction is reduced.

10:
11: X stage
12: Y stage
13: θ stage
14: adsorption chuck
20: Optical system
20A: placement table
20B: through hole
21: Laser light source
22 (22a, 22b): wave plate
23 (23a, 23b): polarized beam splitter
24 (24a, 24b): optical path shutter
25: wave plate
26: condenser lens
27, 28: horizontal reflective mirror
29: vertical reflection mirror
30: beam profile conversion unit
100: laser processing device
130: beam profile conversion prism
LBα: incident light (to the beam profile conversion unit)
LBβ: emitted light (from beam profile conversion unit)
LB0: laser light (emitted from the laser light source)
LB1: 1st quarter light
LB2: second quarter light
LB3 (LB3a, LB3b): Laser light for irradiation

Claims (5)

A laser processing apparatus for processing a workpiece by irradiating laser light,
A stage portion for fixing the workpiece;
An optical system for irradiating a laser beam emitted from a laser light source to the workpiece fixed to the stage from a condenser lens;
The optical system,
Branching means for branching the laser light emitted from the laser light source into a first branched light and a second branched light;
Conversion means for rotating the beam profile of the second branched light by 90 ° with respect to the traveling direction;
Optical path commoning means for commonizing the optical path for irradiation until the converging lens of the second branched light passes through the first branched light and the conversion means;
And selective blocking means for selectively blocking said first and second branched light between said branching means and said optical path commoning means,
When making the said 1st branched light which passed through the said optical path commoning means into a 1st irradiation laser beam, and making the said 2nd branched light which passed through the said commonization means into a 2nd irradiation laser beam,
The first irradiation laser light having the same beam profile and orthogonal to the workpiece fixed to the stage by switching the blocking of the first branched light and the second branched light by the selective blocking means. And any one of said 2nd irradiation laser beams can be selectively irradiated, The laser processing apparatus characterized by the above-mentioned. The method of claim 1, wherein the stage portion is made to be movable in a first direction and a second direction orthogonal to each other,
When the first irradiation laser light is irradiated to the workpiece, the stage portion is moved in the first direction, and when the second irradiation laser light is irradiated to the workpiece, the stage portion is moved in the second direction. Laser processing apparatus characterized by the above-mentioned. The laser processing apparatus according to claim 1 or 2, wherein the conversion means is configured by combining a plurality of mirrors. The laser processing apparatus according to claim 1 or 2, wherein the conversion means is constituted by a prism having a plurality of reflective surfaces. It is a processing method of the to-be-processed object using the laser processing apparatus of Claim 2,
A fixing step of fixing the workpiece to the stage;
An alignment step of bringing the mutually orthogonal extending directions of the lattice-shaped processing target positions set on the workpiece into the first and second directions;
A first processing step of processing a processing target position extending in the first direction by irradiating the first irradiation laser beam while moving the stage portion in the first direction;
And a second processing step of processing the position to be processed extending in the second direction by irradiating the second irradiation laser beam while moving the stage portion in the second direction. Processing method of the workpiece.

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