TW201330309A - Processing method for substrate with LED pattern and processing system for substrate with LED pattern - Google Patents

Abstract

The present invention provides a processing method for a substrate with LED patterns capable of achieving a light-emitting efficiency higher than LED components in the past. The processing method for a substrate with LED patterns is to treat a substrate repeatedly configured with multiple LED unit patterns in a two-dimensional manner, comprising: a step of forming cutting start points, which is to irradiate laser light on the substrate with LED patterns along the lattice-like division lines, so as to form lattice-like cutting start points on the substrate with LED patterns; and a cutting step to cut the substrate with LED patterns along the cutting start points into single dies; also in the step of forming cutting start points, the cutting start points are formed by discretely forming multiple holes of cone-shape, semi-oval-shape or wedge shape or a combination of these shapes on the division lines.

Description

Processing method of substrate with LED pattern and processing system of substrate with LED pattern

The present invention relates to a processing method for singulating a patterned substrate in which a plurality of unit patterns are repeatedly arranged two-dimensionally on a substrate.

An LED (Light Emitting Diode) device is manufactured by a process in which a unit pattern of an LED element is two-dimensionally repeated on a substrate (wafer, mother substrate) such as sapphire. The substrate (substrate having an LED pattern) is cut (divided) at a predetermined division position called a boundary in a lattice shape, and is singulated (wafered). A method of forming a continuous scribe line by a laser scribing method such as a denuding method or an LMA (Laser Melting Alteration) method is known as a method of forming a starting point of the starting point at the time of the cutting. (For example, refer to Patent Document 1 and Patent Document 2).

In addition, in order to improve the luminous efficiency (light extraction efficiency) of the LED element obtained by the above-described process, the technique of performing laser scribing in such a manner that the end portion of the LED element after the truncation is formed with fine concavities and convexities is also It is known (for example, refer to Patent Document 3). In the above case, the total reflection generated when the end portion is flat is suppressed by the provision of irregularities at the end portions, whereby the luminous efficiency is improved.

[Background literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2004-165226

[Patent Document 2] International Publication No. 2006/062017

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2011-92970

When the starting point of the segmentation is formed by the laser scribing method, and then the truncation is performed, the process is deteriorated on the surface of the substrate after the laser beam is irradiated regardless of the use of the ablation method or the LMA (Laser Melt Modification) method. Layer, or residual processing residue. When such a work-affected layer or a process residue remains, there is a problem that light from the light-emitting portion of the LED element is absorbed to lower the light extraction efficiency (that is, brightness).

There has also been proposed a method of suppressing the decrease in luminance by minimizing the formation volume of the work-affected layer. However, as long as a certain degree of the work-affected layer remains, the brightness is inevitably reduced more or less.

Further, the method disclosed in Patent Document 3 can improve the luminous efficiency in principle, but the processing residue is likely to remain on the LED chip after the cutting. Therefore, even if the LED chip is used, the effect of improving the luminous efficiency of the LED element cannot be sufficiently obtained.

The present invention has been made in view of the above problems, and an object of the invention is to provide a method for processing a substrate having an LED pattern of an LED element which is excellent in luminous efficiency, and a processing system for realizing the same.

In order to solve the above-described problems, the invention of claim 1 is a method of processing a substrate having an LED pattern in which a plurality of LED unit patterns are repeatedly arranged two-dimensionally on a substrate, and includes: forming a division starting point a step of dividing the predetermined line by a predetermined line along a predetermined grid The substrate of the LED pattern is irradiated with the laser light, and the starting point of the segmentation is formed in a lattice shape on the substrate having the LED pattern; and the step of cutting is singulated by cutting the substrate with the LED pattern along the starting point of the segmentation; In the above-described division start point forming step, the division start point is formed by discretely forming a plurality of hole portions each having a conical shape, a semi-elliptical shape, a wedge shape, or a composite shape of the shapes on the division planned line.

The invention of claim 2 is the method for processing a substrate having an LED pattern according to claim 1, characterized in that in the dividing start point forming step, each of the single pulses of the laser light forms one of the holes.

The invention of claim 3 is the method for processing a substrate having an LED pattern according to claim 1 or 2, wherein in the step of forming the division starting point, the side of the substrate having the LED pattern having the LED pattern is The main surface is irradiated with the above-described laser light, and the plurality of holes are formed on the main surface.

The invention of claim 4 is the method for processing a substrate having an LED pattern according to claim 1 or 2, wherein in the dividing start point forming step, the laser light having the beam diameter of the laser light is Db The repetition frequency is set to R, and when the relative moving speed of the laser light and the substrate with the LED pattern is set to V, by satisfying 0.6 μm ≦Db ≦ 9 μm, 25 mm/sec ≦V ≦ 500 mm/sec The laser light is irradiated under the condition of 2 ≦V/R ≦15 to form the plurality of holes.

The invention of claim 4 is the method for processing a substrate having an LED pattern according to claim 4, characterized in that in the dividing starting point forming step, the laser light from the illuminated surface of the substrate having the LED pattern is directed toward the inside. The offset of the focus position, that is, the defocus value is set to be 0 μm or more and 30 μm. In the lower range, the pulse energy of the above-described laser light is set to a range of 10 μJ or more and 500 μJ or less.

The invention of claim 6 is the method for processing a substrate having an LED pattern according to claim 1 or 2, further comprising the step of: forming a protective film on the substrate having the LED pattern before the step of forming the segmentation starting point The main surface having the side of the LED pattern forms a protective film; and the protective film removing step removes the protective film after forming the dividing starting point; and in the dividing starting point forming step, the ray is irradiated from the protective film The above-described division starting point is formed by the light.

The invention of claim 7 is characterized in that it is a system for processing a substrate having an LED pattern in which a plurality of LED unit patterns are two-dimensionally repeated on a substrate, and includes: a laser processing apparatus including an exit The source of the laser light and the platform for fixing the substrate with the LED pattern are configured to move the laser light to the LED with a predetermined scanning line while moving relative to the platform. a substrate on the pattern; and a cutting device that cuts the substrate with the LED pattern at a specific cutoff position by a three-point support method; and the laser processing device is defined as a grid along the line of the predetermined processing line Forming the predetermined line to illuminate the substrate having the LED pattern by discretely forming a plurality of holes each having a conical shape, a semi-elliptical shape, a wedge shape, or a composite shape of the shapes on the predetermined dividing line The laser light is formed in a lattice shape on the substrate having the LED pattern, and the cutting device is formed by using the substrate with the LED pattern The segmentation starting point is cut off to make it singular.

According to a seventh aspect of the invention, in the processing system of the substrate having the LED pattern of the seventh aspect of the invention, when the laser processing apparatus forms the division starting point, each of the single pulses of the laser light forms one of the holes.

The invention of claim 9 is the processing system for a substrate having an LED pattern according to claim 7 or 8, wherein the laser processing apparatus is configured to set the beam diameter of the laser light to Db to repeat the laser light. The frequency is set to R, and when the relative moving speed of the above-mentioned laser light and the substrate with the LED pattern is set to V, by satisfying 0.6 μm ≦Db ≦ 9 μm, 25 mm/sec ≦V ≦ 500 mm/sec and 2 The plurality of holes are formed by irradiating the laser light under the condition of ≦V/R≦15.

The invention of claim 10 is the processing system for a substrate having an LED pattern according to claim 9, wherein when the laser processing apparatus forms the division starting point, the illuminated surface of the substrate having the LED pattern is directed toward the inside. The defocus value of the offset position of the laser light is set to a range of 0 μm or more and 30 μm or less, and the pulse energy of the laser light is set to a range of 10 μJ or more and 500 μJ or less.

According to the inventions of the first aspect to the tenth aspect, the LED wafer having the uneven structure at the end portion and having less processing residue can be obtained. By using the above LED chip, it is possible to realize an LED element having higher luminous efficiency than before.

In particular, according to the invention of claim 3, since the uneven structure is formed at a portion closer to the LED pattern (light emitting portion), the luminous efficiency of the LED element can be further improved.

<Processing object>

1 is a schematic cross-sectional view showing a configuration of a substrate (hereinafter, simply referred to as a substrate) 10 having an LED pattern to be diced (wafered) in the present embodiment. In the present embodiment, the substrate 10 in which the LED pattern 102 is provided on one main surface of the sapphire substrate (sapphire single crystal substrate) 101 is singulated to obtain an LED wafer. 2 is a top view of the substrate 10.

As the sapphire substrate 101, a thickness of 70 μm to 200 μm is used. A preferred example is to use a 100 μm thick sapphire substrate 101. Moreover, generally, the LED pattern 102 is formed to have a thickness of about several μm. Moreover, the LED pattern 102 may also have irregularities.

The LED pattern 102 has a configuration in which a plurality of unit patterns UP each of which is formed into one LED wafer after singulation is repeatedly arranged two-dimensionally. In addition, in FIG. 2, four unit patterns UP are shown, but this is only a convenient illustration, and actually more unit pattern UP is arrange|positioned.

The LED pattern 102 is epitaxially formed on the sapphire substrate 101 to form a light-emitting layer including a group III nitride semiconductor represented by, for example, GaN (gallium nitride), and a plurality of other thin film layers 102a, and further formed on the thin film layer 102a. In the LED element (LED wafer), the electrode pattern 102b of the current-carrying electrode is formed.

The boundary portion of each unit pattern UP is a predetermined predetermined position of the substrate 10, and is a boundary ST for irradiating the laser light in the following form. The boundary ST is usually a width of about several tens of μm, and is set to be in a lattice shape when the LED pattern 102 is viewed in plan. In addition, it is not required in the part of the boundary ST The sapphire substrate 101 is exposed, and the thin film layer 102a serving as the LED pattern 102 may be continuously formed.

<Summary of processing>

Next, an outline of processing for performing the singulation of the substrate 10 will be described. The processing for singulating the substrate 10 includes a division starting point forming step of forming a division starting point by irradiating the boundary ST of the substrate 10 with laser light, and a cutting step of cutting off the substrate 10 passing through the dividing starting point forming step ( The LED chip is obtained by dividing). These steps can be achieved, for example, by a processing system having the laser processing apparatus 50 and the cutting apparatus 150 described below.

Figure 3 is a top plan view of the substrate 10 after the step of forming the segmentation starting point. In the step of forming the splitting point, the laser beam (pulse laser light) is intermittently irradiated along the extending direction of the boundary track ST, whereby the constituent material of the substrate 10 existing at the position to be irradiated and directly below is melted, The form of evaporation, scattering, and the like disappears, and a plurality of holes 103 having a conical shape, a semi-elliptical shape, a wedge shape, or a composite shape of the shapes are formed discretely, and a hole portion 103 having a circular shape in a top view as shown in FIG. Further, the shape of the hole portion 103 differs depending on the irradiation conditions of the laser light.

As the laser light source SL, a Nd:YAG laser is preferably used. Alternatively, it may be in the form of a Nd:YVO ₄ laser or other solid laser.

In the present embodiment, a processing form in which the arrangement of the hole portions 103 as shown in FIG. 3 is formed on the boundary track ST by irradiating the laser light is also referred to as dotted line processing. In addition, the plurality of holes 103 obtained by the above-described dotted line processing are next Since the truncation step is the starting point of the truncation (dividing), the arrangement of the hole portions 103 as shown in FIG. 3 is also referred to as the division starting point 104.

Further, a protective film may be formed on the LED pattern 102 before the above-described division start point forming step, and the laser beam may be irradiated from the protective film in the division start point forming step. It is preferable to form a protective film containing, for example, a resin or the like in a thickness of about 0.5 to 3 μm. This can be achieved by applying a stock solution for forming a protective film obtained by dispersing a protective film forming component, dissolving it in a medium such as water, or the like by a spin coater, followed by drying or the like. As a stock solution for forming a protective film, for example, Nanoshelter (registered trademark) manufactured by Nissin Seiko Co., Ltd. can be used. Before the cutting step, the protective film remaining after the formation of the splitting starting point is removed by water washing (high-pressure water washing, brush cleaning, ultrasonic cleaning, etc.). In the above case, the substance (debris) scattered from the hole portion 103 by the irradiation of the laser light adheres to the protective film, but is removed together with the protective film by washing, so that it is preferably suppressed from remaining in the protective film. On the substrate 10.

In the step of cutting off the dividing start point forming step, the substrate 10 is cut along the dividing starting point 104 formed at the boundary ST. The cutting of the substrate 10 is achieved by stretching the cracks from the respective holes 103 by means of three-point support. The substrate 10 is diced (wafered) into individual LED wafers by performing the above-described cutting with respect to all of the division starting points 104 formed on the substrate 10.

4 is an SEM (Scanning Electron Microscope) image of a portion of a side surface of an LED wafer obtained by a truncation step. In FIG. 4, near the upper end portion (upper side surface) of the LED wafer obtained by the truncation step, it is observed that the truncation step is divided into two parts. The hole portion 103 is a recess. According to the above-described case of the hole portion 103, it is understood that the hole portion 103 before the cutting is conical.

Further, in the present embodiment, the substrate 10 subjected to the dotted processing is cut along the division starting point 104, whereby a concave-convex structure in which the concave portion and the flat portion alternate are formed in the vicinity of the upper end portion of the LED wafer.

The uneven structure has an effect of improving the luminous efficiency when the LED chip is used as an LED element. This is because the light from the light-emitting layer is easily reflected to the outside without being totally reflected when the end portion of the wafer is uneven. In other words, the boundary line ST of the substrate 10 having the LED pattern is subjected to dot line processing, and the cut along the boundary track ST is performed, whereby an LED chip of an LED element capable of achieving excellent luminous efficiency can be obtained.

<Using point light processing of laser light>

Next, the details of the above-described dotted line processing will be described. Fig. 5 is a view for explaining an irradiation form of laser light in the dotted line processing. More specifically, FIG. 5 shows the relationship between the repetition frequency of the laser light, the moving speed of the stage on which the substrate 10 is placed when irradiating the laser light, and the center distance of the beam spot of the laser light. Here, as in the laser processing apparatus 50 described below, the source of the laser light is fixed, and the stage on which the substrate 10 is placed is moved, thereby achieving relative scanning of the laser light with respect to the substrate 10.

As shown in Fig. 5, when the repetition frequency of the laser light is R (kHz), one laser pulse is emitted from the laser light source every 1/R (msec). When the stage on which the substrate 10 is placed is moved at a speed V (mm/sec), the substrate 10 moves only V × (1/R) = between the issuance of a pulse and the next laser pulse. V/R (μm), therefore, the interval between the center position of the beam of a certain laser pulse and the center position of the beam of the laser pulse emitted next, that is, the center interval of the beam point is defined by Δ(μm) Δ=V/R.

According to the above situation, the beam diameter (beam waist diameter) Db of the laser light LB on the surface of the substrate 10 is spaced from the center point of the beam spot by Δ satisfying Δ>Db..... (Formula 1)

In the case of the laser light, the individual laser pulses do not overlap when the laser light is scanned.

The dotted line processing of the present embodiment is realized by utilizing this relationship. In other words, when the laser pulses (single pulses) successively emitted from the laser light source are sequentially and discretely irradiated along the boundary ST, the constituent substances of the substrate 10 present at each of the irradiated positions and immediately below are irradiated. The energy of the laser pulse is heated and disappears in the form of melting, evaporation, and scattering. Thereby, a plurality of hole portions 103 are sequentially formed. In other words, one hole portion 103 is formed at the irradiation position by each single pulse, and a division start point 104 as an arrangement of the hole portions 103 is formed.

However, generally, in the case where the laser beam is irradiated with the beam diameter Db, the diameter (processed diameter) Dh of the processed region (the hole portion 103 in the case of the present embodiment) on the surface of the substrate 10 is larger than the beam diameter Db. Therefore, in the present embodiment, at the time of the dotted line processing, at least Δ>Dh=Db+α....(Expression 2) is satisfied.

In the form of the relationship, the laser light is irradiated. Here, α is an empirically defined positive real number based on the value of the beam diameter Db and the value of the processed diameter Dh. Specifically, in the preliminary experiment or the like, the difference value of the processing diameter Dh formed when the laser beam is irradiated with the beam diameter Db of various values is specified in advance, and the real number α may be defined based on the difference value.

On the other hand, when the distance Δ between the center points of the beam spots corresponding to the distance between the hole portions 103 is too large, the uneven portion on the end portion of the LED chip is reduced, and the luminous efficiency when used as an LED element is lowered. There is a problem that the cutoff characteristic is deteriorated from the beginning and the cut along the boundary ST cannot be achieved, and the yield of the LED chip is lowered. That is, the beam spot center interval Δ must be specified in consideration of this aspect. Specifically, the beam spot center interval Δ is specified to be 15 μm or less.

Further, when the processing diameter Dh is small, part of the constituent material of the substrate 10 existing at the irradiation position when the laser light is irradiated does not disappear, and it is easy to remain as the processing residue in the hole portion 103, which is not preferable. On the other hand, if the processing diameter Dh is too large, the effect of forming the unevenness by the provision of the hole portion 103 cannot be sufficiently obtained, which is still unsatisfactory. The size of the beam diameter Db which affects the size of the machining diameter Dh must be specified in consideration of this aspect.

In the present embodiment, in view of the above, the irradiation conditions of the laser light and the platform are set in the range of 0.6 μm ≦Db ≦ 9 μm, 25 mm/sec ≦V ≦ 500 mm/sec, and 2 ≦V/R ≦15. Driving conditions.

Further, in the present embodiment, the dot-line processing for forming the division start point 104 may be performed on the main surface on the side of the LED pattern 102 on the substrate 10, or the LED pattern may be formed on the substrate 10. The opposite side of the main surface of the 102 side is in the form of dot line processing for forming the division starting point 104. However, since the former has a concavo-convex structure formed closer to the LED pattern 102 (light emitting portion) than the latter, it is more preferable from the viewpoint of improving the luminous efficiency of the LED element.

In addition, the substances constituting the LED pattern 102 are compared with the sapphire substrate 101. Since the substance is more likely to be lost by the irradiation of the laser light, the material constituting the LED pattern 102 does not remain as a processing residue if the dotted line is processed under the condition that the sapphire is sufficiently suppressed to remain as a processing residue.

<Inhibition of processing residue>

As described above, in the present embodiment, the boundary line processing is performed in the dividing start point forming step, and the cutting step is performed, whereby the uneven structure is formed at the end portion of the wafer, thereby realizing luminous efficiency in the LED element. improve.

On the other hand, Patent Document 3 discloses a technique in which a concave portion is provided adjacent to each other at a wafer end portion by laser processing in a form in which a single-pulse processed region is connected and subsequent cutting. The concavo-convex structure improves the luminous efficiency of the LED element.

When the two are compared, the flat portion of the uneven structure of Patent Document 3 is remarkably small, and the effect of suppressing total reflection is high, and the effect of improving luminous efficiency is considered to be high. However, in the case of performing laser processing in order to form the uneven structure disclosed in Patent Document 3, by the irradiation of each single pulse, the substance which should originally be scattered to the outside of the concave portion is irradiated to the previous single pulse. The adjacent concave portion formed by the irradiation is scattered, and the phenomenon of adhesion as a processing residue is apt to occur. Therefore, the inventors of the present invention confirmed that the effect of improving the luminous efficiency as expected in the LED element cannot be obtained.

On the other hand, in the case of the dotted line processing of the present embodiment, since the hole portions 103 are only separately present, when the respective single pulses are irradiated, the substance does not occur from the irradiated region to the side of the hole portion 103. In the case of flying, etc. If the disappearance of the substance occurs, it is limited to the case where it is caused by scattering from the surface of the substrate 10 or the like. Therefore, in the case of the present embodiment, if laser light is irradiated in a form in which the substance existing in the irradiated position and immediately below is scattered, the processing residue in the hole portion 103 can be generated. The suppression is minimal.

The processing in the above configuration is performed by setting the beam diameter Db, the repetition frequency R, or the moving speed V of the stage to the above range, and the offset amount of the focus position of the laser light from the surface of the substrate 10, that is, the defocus value or The pulse energy of the laser light is adjusted as appropriate. In other words, in the case where the conditions are preferably set and the processing method of the present embodiment is performed, an LED element having more excellent luminous efficiency can be obtained as compared with the case of applying the processing method disclosed in Patent Document 3.

Specifically, the defocus value is set to a positive direction from the surface of the substrate toward the inside, and is preferably set to a range of 0 μm or more and 30 μm or less. Further, the pulse energy is preferably set to a range of 10 μJ or more and 500 μJ or less.

<Laser processing device>

Fig. 6 is a schematic view showing the configuration of a laser processing apparatus 50 which is one of the laser processing apparatuses which can perform the above-described dotted line processing. The laser processing apparatus 50 mainly includes a stage 7 on which the substrate 10 is placed, and a controller 1 that performs various operations (observation operation, alignment operation, processing operation, and the like) of the laser processing apparatus 50, and is configured as follows. The substrate 10 can be processed by irradiating the substrate 10 placed on the stage 7 with the laser light LB.

The platform 7 is movable in the horizontal direction by the moving mechanism 7m. The moving mechanism 7m causes the platform 7 to be in the horizontal plane by the action of a driving unit not shown. The specific XY moves in two axes. Thereby, the movement of the laser light irradiation position or the like is achieved. Further, regarding the moving mechanism 7m, the rotation (θ rotation) in the horizontal plane centering on the specific rotation axis can be performed independently of the horizontal driving.

Further, in the laser processing apparatus 50, it is possible to directly observe the front side of the substrate 10 from the side that irradiates the laser light (referred to as the front side) by an imaging unit (not shown) or to mount it on the platform 7. The side (referred to as the back side) is observed through the platform 7 and viewed from the back side.

As described above, the stage 7 is formed of a transparent member such as quartz, and a suction pipe (not shown) which is an intake passage for adsorbing and fixing the substrate 10 is provided inside. The suction piping is provided by, for example, machining a specific position of the platform 7 by machining.

In a state in which the substrate 10 is placed on the stage 7, the suction pipe is sucked by a suction unit 11 such as a suction pump, and the suction pipe is placed on the front side of the mounting surface of the platform 7. The suction holes provide a negative pressure, whereby the substrate 10 (and the transparent substrate protection sheet 4) are fixed to the stage 7. In addition, in the case where the substrate 10 to be processed is attached to the transparent substrate protective sheet 4 in FIG. 6, the attachment of the transparent substrate protective sheet 4 is not necessarily required.

More specifically, in the laser processing apparatus 50, the laser beam LB is emitted from the laser light source SL, and is reflected on the stage 7 after being reflected by the dichroic mirror 51 included in the lens barrel (not shown). The laser beam LB is condensed by the condensing lens 52 in such a manner that the processed portion of the upper substrate 10 is focused, and is irradiated onto the substrate 10. By combining the irradiation of the above-described laser light LB and the movement of the stage 7, the laser light LB can be scanned while being relatively scanned with respect to the substrate 10. Processing of the board 10. For example, in order to divide the substrate 10, it is possible to perform processing such as groove processing (scribe line) on the surface of the substrate 10.

Further, in the laser processing apparatus 50, when processing is performed, the laser light LB may be irradiated in a defocused state in which the focus position is intentionally shifted from the surface of the substrate 10 as needed. In the present embodiment, it is preferable to set the defocus value (the amount of shift from the surface of the substrate 10 to the focus position in the direction of the inside) to a range of 0 μm or more and 30 μm or less.

As the laser light source SL, as described above, it is preferable to use a Nd:YAG laser. Alternatively, a Nd:YVO ₄ laser or other solid laser may be used. Further, the laser light source SL preferably has a Q switch.

Further, the wavelength or output of the laser light LB emitted from the laser light source SL, the repetition frequency of the pulse, the adjustment of the pulse width, and the like are realized by the illumination control unit 23 of the controller 1. When the processing control unit 25 issues a specific setting signal according to the processing mode setting data D2 to the irradiation control unit 23, the irradiation control unit 23 sets the irradiation conditions of the laser light LB in accordance with the setting signal.

Further, as described above, in the present embodiment, it is preferable to use a Nd:YAG laser as the laser light source SL, and in particular, it is preferable to use a three-time harmonic (wavelength of about 355 nm). . Further, the pulse width is preferably 1 nsec or more and 200 nsec or less. The repetition frequency R of the pulse can be set within a range of 1 kHz ≦ R ≦ 250 kHz. The pulse energy can be set within a range of 10 μJ or more and 50 μJ or less.

The laser light LB is condensed by the condensing lens 52 to be irradiated with the beam diameter Db in the range of 0.6 μm ≦ Db ≦ 9 μm described above.

In addition, the polarization state of the laser light LB emitted from the laser light source SL can be It is circularly polarized or linearly polarized. However, in the case of linear polarization, it is preferable that the polarization direction is substantially parallel to the scanning direction from the viewpoint of the bending of the processed cross section and the energy absorption rate in the crystalline material to be processed, for example, The angle is within ±1°. Further, in the case where the emitted light is linearly polarized, the laser processing apparatus 50 preferably includes an attenuator (not shown). The attenuator is disposed at an appropriate position on the optical path of the laser beam LB, and functions to adjust the intensity of the emitted laser light LB.

The controller 1 further includes a control unit 2 that controls the operation of the respective units to realize processing of the substrate 10 in various forms described below, and a memory unit 3 that stores a program for controlling the operation of the laser processing apparatus 50. 3p or various materials referenced during processing.

The control unit 2 is realized by a general-purpose computer such as a personal computer or a microcomputer, and the program 3p stored in the memory unit 3 is read by the computer and executed, and various components are used as the functional part of the control unit 2. Implemented as a component.

Specifically, the control unit 2 mainly includes a drive control unit 21 that controls the operation of various driving portions related to the machining process such as the driving of the stage 7 by the moving mechanism 7m or the focusing operation of the collecting lens 52; the imaging control unit 22 And controlling the imaging of the substrate 10 by an imaging unit (not shown), the irradiation control unit 23 for controlling the irradiation of the laser light LB from the laser light source SL, and the adsorption control unit 24 for controlling the suction unit 11 The adsorption and fixation operation of the substrate 10 to the stage 7; and the processing unit 25 performs processing processing on the processing target position based on the supplied processing position data D1 and the machining mode setting data D2.

The memory unit 3 is realized by a memory medium such as a ROM (Read Only Memory), a RAM (Random Access Memory), or a hard disk. Further, the storage unit 3 may be realized by realizing the components of the computer of the control unit 2, or may be provided separately from the computer in the case of a hard disk.

Further, various input instructions given by the operator to the laser processing apparatus 50 are preferably performed by a GUI (Graphical User Interface) implemented in the controller 1. For example, a processing processing menu is provided on the GUI in accordance with the action of the processing unit 25.

By having the configuration as described above, the laser processing apparatus 50 can preferably perform the above-described dotted processing. Other than this, it is also possible to appropriately perform other processing by appropriately adjusting the conditions and the like.

For example, it is preferable to select a processing mode corresponding to various processing contents in accordance with a processing menu available to the operator provided by the controller 1 by the action of the processing unit 25. In the memory unit 3 of the controller 1, the processing position data D1 in which the position of the boundary line ST of the substrate 10 as the planned dividing line is described is stored, and the description corresponds to the form of the laser processing in each processing mode. The processing mode setting data D2 regarding the conditions of the respective parameters of the laser light or the driving conditions of the platform 7 (or the settable ranges). The machining processing unit 25 acquires the machining position data D1, acquires a condition corresponding to the selected machining mode from the machining mode setting data D2, and passes the drive control unit 21 or the illumination control unit in such a manner as to perform an operation corresponding to the condition. 23 and other parts and control the movement of each department Work.

<Truncation step>

Fig. 7 is a schematic view showing a state in which the substrate 10 is cut off in the cutting step. In FIG. 7, the case where the cutting device 150 including the lower side cutting bars B1 and B2 and the upper side cutting bar B3 is cut off is exemplified. In the state in which the substrate 10 is the lower side where the boundary line ST is formed, the upper side cutting bar B3 is oriented toward the sapphire substrate in a state where the two lower cutting bars B1 and B2 support both sides of the boundary track ST. The back surface 101a of 101 and the cut-off position BP immediately below the dividing start point 104 (directly above in FIG. 7) are lowered, whereby the substrate 10 can be cut off. More specifically, the force applied to the substrate 10 from the lower side by the lower cut bars B3 and the upper cut bars B3 is cut from the respective hole portions 103 toward the back side of the sapphire substrate 101. Further, the substrate 10 is extended toward the arrangement direction of the hole portions 103, whereby the substrate 10 is cut along the division starting point 104.

The cutting is sequentially performed in the same manner with respect to all of the dividing starting points 104 formed on the substrate 10, whereby the substrate 10 is singulated into individual LED chips. That is, a plurality of LED chips having a concavo-convex structure at the end portion are obtained.

As described above, according to the present embodiment, the dot line processing is performed, and the substrate is cut along the arrangement of the hole portions, whereby an LED wafer having an uneven structure at the end portion and less processing residue can be obtained. By irradiating the pulsed laser light while scanning, a plurality of hole portions such as a conical shape are discretely formed along the direction in which the hole extends in the boundary of the substrate. By using the above LED chip, it is possible to realize an LED element having higher luminous efficiency than before.

[Examples]

In order to easily evaluate the influence of the formation of the division starting point 104 on the substrate 10 on the luminous efficiency of the LED element, a plurality of sapphire substrates are prepared, and each of the processing methods including the above-described dotted line processing is performed before and after processing. The amount of light transmitted.

Fig. 8 is a view showing a state of measurement of the amount of transmitted light of the sapphire substrate WS. As shown in FIG. 8, the sapphire substrate WS is formed in a rectangular shape in a plan view, and a processed portion P, which is a plurality of straight portions separated from each other, is defined at one end portion of one main surface. The processed portion P is provided so as to traverse the main surface from one side portion of the substrate WS toward the other side portion.

The measurement of the amount of transmitted light is performed by inserting the sapphire substrate WS into the window portion 202 of a portion of the integrating sphere 201 of the measuring device 200 shown in FIG. 8 in a state in which the sapphire substrate WS is housed inside the processed portion P. In this state, the incident light LI is emitted from the other end portion of the sapphire substrate WS located outside the integrating sphere 201 by the LED light source 203, and the transmitted light LT is detected by the photodetector 204 attached to the integrating sphere 201.

Specifically, four sapphire substrates WS were prepared for the examples and the three comparative examples (Comparative Examples 1 to 3). Further, the amount of transmitted light was measured before processing for each. Further, the sapphire substrate WS other than Comparative Example 1 was processed in the following manner, and the amount of transmitted light of each was measured again. In the sapphire substrate WS of Comparative Example 1, the amount of transmitted light was measured again without performing any processing on the processed portion P.

As an embodiment, it is prepared to form a hole portion discretely in the processed portion P by the above-described dotted line processing. In an embodiment, the beam diameter Db is set to about 2.5. Μm, the machining speed is set to 180 mm/sec, the repetition frequency is set to 100 kHz, the pulse energy is set to 16.5 μJ, and the defocus value is set to 5.0 μm.

Further, as a comparative example 2, a sapphire substrate WS in which a continuous groove portion having a V-shaped cross section is formed in the workpiece portion P is prepared. In Comparative Example 2, the beam diameter Db was set to about 2.5 μm, the processing speed was set to 100 mm/sec, the repetition frequency was set to 70 kHz, the pulse energy was set to 16.5 μJ, and the defocus value was set to 5.0 μm. .

Further, as a comparative example 3, a sapphire substrate WS in which a continuous concave portion in a form as disclosed in Patent Document 3 is provided in the workpiece P is prepared. In Comparative Example 3, the beam diameter Db was set to about 2.5 μm, the processing speed was set to 70 mm/sec, the repetition frequency was set to 10 kHz, the pulse energy was set to 50.0 μJ, and the defocus value was set to 8.0 μm. .

Fig. 9 is a graph showing the value (normalized transmitted light amount) obtained by normalizing the amount of transmitted light after processing in the examples and the comparative examples by the amount of transmitted light before processing. As shown in Fig. 9, in the examples, the normalized transmitted light amount value of Comparative Example 1 which was second only to the unprocessed was obtained, and the value was also a large value of about 0.92. On the other hand, in Comparative Example 2 and Comparative Example 3, the normalized transmitted light amount values were small, and were about 0.76 and 0.58.

It is considered that the decrease in the amount of transmitted light is mainly caused by the fact that light is easily absorbed in the workpiece P due to the residual of the processing residue or the formation of the work-affected layer, etc., as shown in FIG. As a result, it was considered that the dot-line processing as in Example 1 was less likely to cause the residue of the processing residue than the processing of Comparative Example 2 and Comparative Example 3. That is, this means that the processing method of the above embodiment is for obtaining an LED element excellent in luminous efficiency. On the other hand, it is more suitable for the singulation of a substrate having an LED pattern than the conventional processing method.

1‧‧‧ controller

2‧‧‧Control Department

3‧‧‧Memory Department

3P‧‧‧ program

4‧‧‧Transparent substrate protection sheet

7‧‧‧ platform

7m‧‧‧mobile agencies

10‧‧‧Substrate

21‧‧‧Drive Control Department

22‧‧‧Video Control Department

23‧‧‧Enhanced Control Department

24‧‧‧Adsorption Control Department

25‧‧‧Processing Department

50‧‧‧ Laser processing equipment

51‧‧‧ dichroic mirror

52‧‧‧ Concentrating lens

101‧‧‧Sapphire substrate

101a‧‧‧Back of the substrate

102‧‧‧LED pattern

102a‧‧‧film layer

102b‧‧‧electrode pattern

103‧‧‧ Hole Department

104‧‧‧ starting point

150‧‧‧Truncation device

200‧‧‧ (transmitted light) measuring device

201‧‧·score ball

202‧‧‧ Window Department

203‧‧‧LED light source

204‧‧‧Photodetector

B1, B2‧‧‧ lower truncated rod

B3‧‧‧Upper truncated rod

BP‧‧‧ truncated position

D1‧‧‧Processing location data

D2‧‧‧Processing mode setting data

LB‧‧ ‧ laser

LI‧‧‧ incident light

LT‧‧‧through light

P‧‧‧Processed Department

SL‧‧‧Laser light source

ST‧‧‧ Jiedao

UP‧‧‧ unit pattern

WS‧‧‧Sapphire substrate

Fig. 1 is a schematic cross-sectional view showing the configuration of a substrate 10 having an LED pattern.

2 is a top view of the substrate 10.

Figure 3 is a top plan view of the substrate 10 after the step of forming the segmentation starting point.

Figure 4 is an SEM image of a portion of the side of the LED wafer obtained by the truncation step.

Fig. 5 is a view for explaining an irradiation form of laser light in the dotted line processing.

FIG. 6 is a schematic view showing the configuration of the laser processing apparatus 50.

Fig. 7 is a schematic view showing a state in which the substrate 10 is cut off in the cutting step.

Fig. 8 is a view showing a state of measurement of the amount of transmitted light of the sapphire substrate WS.

Fig. 9 is a graph showing the normalized transmitted light amount values of the examples and the comparative examples.

103‧‧‧ Hole Department

104‧‧‧ starting point

ST‧‧‧ Jiedao

Claims (10)

A method for processing a substrate having an LED pattern, characterized in that the method of processing a substrate having an LED pattern in which a plurality of LED unit patterns are two-dimensionally repeated on a substrate is processed, and includes a step of forming a division starting point And irradiating the substrate with the LED pattern along the predetermined dividing line which is defined in a lattice shape, and forming a dividing start point on the substrate having the LED pattern in a lattice shape; and cutting the step by using the LED The substrate of the pattern is cut along the dividing starting point to be singulated; and in the dividing starting point forming step, each of the dividing line is discretely formed into a conical shape, a semi-elliptical shape, a wedge shape or the like The plurality of hole portions of the composite shape form the division starting point. A method of processing a substrate having an LED pattern according to claim 1, wherein in the dividing start point forming step, each of the single pulses of the laser light forms one of the holes. The method for processing a substrate having an LED pattern according to claim 1 or 2, wherein in the dividing starting point forming step, the main surface of the LED pattern having the side of the LED pattern is irradiated with the laser light, and The main surface forms the plurality of holes. The method for processing a substrate having an LED pattern according to claim 1 or 2, wherein in the dividing starting point forming step, the beam diameter of the laser light is Db, and the repetition frequency of the laser light is R, When the relative movement speed of the laser light and the substrate with the LED pattern is set to V, by satisfying: The above-described plurality of holes were formed by irradiating the above-described laser light under the conditions of 0.6 μm ≦Db ≦9 μm, 25 mm/sec ≦V ≦ 500 mm/sec and 2 ≦V/R ≦15. The method for processing a substrate having an LED pattern according to claim 4, wherein in the dividing starting point forming step, an offset amount from a focus position of the laser light from the illuminated surface of the substrate having the LED pattern toward the inside is dispersed The focal value is set to a range of 0 μm or more and 30 μm or less, and the pulse energy of the above-described laser light is set to a range of 10 μJ or more and 500 μJ or less. The method for processing a substrate having an LED pattern according to claim 1 or 2, further comprising: a protective film forming step of forming the main surface on the side of the substrate having the LED pattern having the LED pattern before the dividing starting point forming step And a protective film removing step of removing the protective film after the dividing start point is formed; and in the dividing starting point forming step, the dividing starting point is formed by irradiating the laser light from the protective film. A processing system for a substrate having an LED pattern, which is a system for processing a substrate having an LED pattern by repeatedly arranging a plurality of LED unit patterns on a substrate, and comprising: a laser processing device And comprising: a source for emitting the laser light and a platform for fixing the substrate with the LED pattern, wherein the laser light is moved relative to the platform to enable the laser light to follow a specific Processing the predetermined line scanning to illuminate the substrate with the LED pattern; and cutting the device, the three-point support method is used to cut the substrate with the LED pattern at a specific cut-off position; and the laser processing device is The predetermined line to be processed is defined as a grid-shaped dividing line, and a plurality of holes each having a conical shape, a semi-elliptical shape, a wedge shape, or a composite shape of the shapes are discretely formed on the predetermined dividing line. Irradiating the laser light on the substrate having the LED pattern, and forming a division starting point in a lattice shape on the substrate having the LED pattern; and the cutting device is configured to cut the substrate with the LED pattern along the dividing starting point Uniform. A processing system for a substrate having an LED pattern according to claim 7, wherein when the laser processing apparatus forms the division starting point, each of the single pulses of the laser light forms one of the holes. The processing system for a substrate having an LED pattern according to claim 7 or 8, wherein the laser processing apparatus is configured to set the beam diameter of the laser light to Db, and set the repetition frequency of the laser light to R, and the laser light is used. When the relative moving speed with the above-mentioned substrate having the LED pattern is set to V, the condition of satisfying: 0.6 μm ≦ Db ≦ 9 μm, 25 mm/sec ≦ V ≦ 500 mm/sec, and 2 ≦ V / R ≦ 15 The above-described plurality of holes are formed by irradiating the above-described laser light. A processing system for a substrate having an LED pattern according to claim 9, wherein When the laser processing apparatus forms the division start point, the defocus value which is an offset amount of the focus position of the laser beam from the illuminated surface of the substrate having the LED pattern toward the inside is set to be in a range of 0 μm or more and 30 μm or less. Further, the pulse energy of the above-described laser light is set to a range of 10 μJ or more and 500 μJ or less.