JP2014216556A - Processing method for substrate with pattern and processing apparatus for substrate with pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing method capable of decreasing the number of formation of processing traces than before, without causing failure in dividing a substrate with a pattern.SOLUTION: In a method of processing a substrate with a pattern in which a plurality of unit patterns are repeatedly arranged in two-dimension on a single crystal substrate, a division start point formation step for forming a division start point on the substrate by radiating laser light along a processing scheduled line set on the substrate includes a crack extension processing step in which, by radiating laser light while scanning along the processing scheduled line, processing traces formed on the substrate with a pattern by respective unit pulse lights of the laser light are positioned in a discrete manner along the processing schedule line, with a crack extending from respective processing traces to the substrate with a pattern. In the division start point formation step, the crack extension processing step is intermittently performed along the processing scheduled line so that a first region in which the processing traces are formed with constant intervals and a second region in which no processing trace is formed are alternately formed.

Description

  The present invention relates to a method for dividing a substrate with a pattern formed by repeatedly arranging a plurality of unit patterns on a substrate in two dimensions.

  An LED element is provided with a pattern-formed substrate (substrate with an LED pattern) formed in a two-dimensional pattern on a substrate (wafer, mother substrate) such as a sapphire single crystal in a grid pattern. It is manufactured by a process of dividing into divided regions called “streets” and dividing them into chips. Here, the street is a narrow area that is a gap between two parts that become LED elements by division.

  As a method for such division, laser light, which is ultrashort pulse light having a pulse width of the order of psec, is irradiated under the condition that the irradiated region of each unit pulse light is discretely positioned along the planned processing line. Thus, a method for forming a starting point for division along a planned processing line (usually a street center position) is already known (see, for example, Patent Document 1). In the technique disclosed in Patent Document 1, crack extension (crack extension) occurs between the processing marks formed in the irradiated regions of each single pulse light, and the substrate is moved along the crack. By dividing (breaking), singulation is realized.

JP 2011-131256 A

  In a substrate with a pattern as described above, unit patterns are usually arranged along a direction parallel to an orientation flat (orientation flat) provided on a sapphire single crystal substrate and a direction orthogonal thereto. Therefore, in such a patterned substrate, the street extends in a direction parallel to the orientation flat and a direction perpendicular thereto. Therefore, when the substrate with a pattern is divided into pieces, the obtained LED elements have four divided surfaces.

  When such singulation is performed by the method disclosed in Patent Document 1, pulse laser light is irradiated along the planned processing line in the above-described manner in the vicinity of the surface side of the divided surface of each LED element. As a result, minute machining traces are discretely formed in the irradiated region of each single pulse light. Each processing trace is a microscopic hole having a substantially conical shape, a substantially wedge shape, or a substantially columnar shape having a longitudinal direction in the thickness direction of the substrate, and an altered region in which a constituent material such as a sapphire substrate is altered is formed on the surface. Or the altered region itself exists in a substantially cone shape, a substantially wedge shape, or a substantially columnar shape having a longitudinal direction in the thickness direction of the substrate. These processing traces exist as opaque regions that prevent transmission of light emitted from inside the LED element. Therefore, from the viewpoint of improving the light extraction efficiency in the LED element, it is desirable to suppress the formation of processing marks as much as possible. However, simply increasing the formation interval of the processing marks to reduce the number of processing marks requires that the power of the pulse laser beam be increased in order to cause crack extension, and that more power is applied in the break. As a result, there is a high possibility that the portion that becomes the LED element will be damaged, or the patterned substrate along the planned processing line cannot be properly divided, which is not preferable.

  The present invention has been made in view of the above problems, and provides a method for processing a substrate with a pattern that can reduce the number of formation of processing marks as compared with the conventional method without causing a problem in the division of the substrate with a pattern. Objective.

  In order to solve the above-mentioned problems, the invention of claim 1 is a method of processing a patterned substrate formed by repeatedly arranging a plurality of unit patterns on a single crystal substrate in a two-dimensional manner, and is set on the patterned substrate. A split starting point forming step for forming a split starting point on the patterned substrate by irradiating a laser beam along the planned processing line, and an individualization by breaking the patterned substrate along the split starting point And the dividing starting point forming step is formed on the patterned substrate by each unit pulse light of the laser light by irradiating the laser light while scanning along the planned processing line. The processing traces to be performed are discretely positioned along the planned processing line, and from each processing trace to the patterned substrate A crack extension processing step for extending a crack, and in the split starting point forming step, the crack extension processing step is performed to form the first region in which the processing marks are formed at equal intervals, and the crack extension processing. The crack extension processing step is intermittently performed along the planned processing line so that the second regions in which the process is not performed and the processing trace is not formed are alternately formed along the planned processing line. It is characterized by that.

  Invention of Claim 2 is a processing method of the board | substrate with a pattern of Claim 1, Comprising: The size of the said unit pattern in the direction along the said process planned line is said 1st in the direction along the said process planned line. It is an integral multiple of the sum of the size of the region and the size of the second region, and the ratio of the size of the second region to the size of the first region in the direction along the planned processing line is 20/80 or more 60/40 or less.

  Invention of Claim 3 is the processing method of the board | substrate with a pattern of Claim 2, Comprising: In the direction along the said process planned line, the space | interval of the said process trace in the said 1st area | region is 400 micrometers or less, The size of the second region is 100 μm or less.

  Invention of Claim 4 is the processing method of the board | substrate with a pattern of Claim 2 or Claim 3, Comprising: The said process plan line is the 1st process plan line and the 2nd process plan line which mutually orthogonally cross. In the split starting point forming step, the crack extension processing step is performed so that the first region in the first processing line and the first region in the second processing line intersect. It is characterized by that.

  The invention according to claim 5 is a method of processing a substrate with a pattern formed by repeatedly arranging a plurality of unit patterns on a single crystal substrate in a two-dimensional manner, along a planned processing line set for the substrate with a pattern A split starting point forming step for forming a split starting point on the patterned substrate by irradiating laser light, and a breaking step for breaking the patterned substrate into individual pieces by breaking along the split starting point. The division start point forming step irradiates the laser beam while scanning along the planned processing line, so that a processing mark formed on the patterned substrate by each unit pulse light of the laser beam is the processing Crack extension that is positioned discretely along the planned line and that causes cracks to extend from the respective processing marks to the patterned substrate In the split starting point forming step, the crack extension processing step is performed so that the region where the processing mark is formed is unevenly distributed along the planned processing line at equal intervals. The extending process step is intermittently performed along the planned processing line.

  The invention according to claim 6 is an apparatus for processing a substrate with a pattern in which a plurality of unit patterns are repeatedly arranged two-dimensionally on a single crystal substrate, along a planned processing line set for the substrate with a pattern A split starting point forming unit that forms a split starting point on the patterned substrate by irradiating the substrate with a laser beam, and a break unit that breaks the patterned substrate along the split starting point into individual pieces. The division start point forming means irradiates the laser beam while scanning along the planned processing line, so that a processing mark formed on the patterned substrate by each unit pulse light of the laser light is processed. Crack extension that is positioned discretely along the planned line and that causes cracks to extend from the respective processing marks to the patterned substrate A first region where the processing marks are formed at equal intervals by the crack extension processing means, and a second region where the processing marks are not formed. The crack extending process is intermittently performed along the planned line so as to be alternately formed along the planned line.

  According to the first to sixth aspects of the present invention, the patterned substrate can be favorably divided while reducing the number of processing marks as compared to the conventional uniform crack extension processing. For example, when a substrate with a pattern in which unit patterns of optical devices such as LED elements are repeatedly formed is divided and separated into individual LED elements, LED elements with improved light extraction efficiency than before are obtained. can get.

1 is a schematic diagram schematically showing a configuration of a laser processing apparatus 100. FIG. It is a figure for demonstrating the irradiation aspect of the laser beam LB in a crack extension process. It is the model top view and partial enlarged view of the board | substrate W with a pattern. The top view of the substrate W with a pattern which shows typically the mode of the formation of the process trace M in the substrate W with a pattern when the intermittent crack extension process is performed along the one process planned line PL in the laser processing apparatus 100. It is. The processing of the patterned substrate W schematically showing how the processing marks M are formed on the patterned substrate W when the laser processing apparatus 100 performs intermittent crack extension processing along one planned processing line PL. It is a vertical sectional view along the planned line PL. It is a top view which shows the mode of formation of the process mark M at the time of performing a uniform crack extension process with respect to the board | substrate W with a pattern by beam spot center space | interval (DELTA) '.

<Laser processing equipment>
FIG. 1 is a schematic diagram schematically showing a configuration of a laser processing apparatus 100 used for dividing a workpiece applicable to the embodiment of the present invention. The laser processing apparatus 100 includes a controller 1 that controls various operations in the apparatus (observation operation, alignment operation, processing operation, etc.), a stage 4 on which the workpiece 10 is placed, and a laser light source SL. It mainly includes an irradiation optical system 5 that irradiates the workpiece 10 with the emitted laser beam LB.

  The stage 4 is mainly composed of an optically transparent member such as quartz. The stage 4 is configured such that the workpiece 10 placed on the upper surface thereof can be sucked and fixed by suction means 11 such as a suction pump. The stage 4 can be moved in the horizontal direction by the moving mechanism 4m. In FIG. 1, a sticky holding sheet 10 a is attached to the workpiece 10, and then the workpiece 10 is placed on the stage 4 with the holding sheet 10 a side as a placement surface. However, the aspect using the holding sheet 10a is not essential.

  The moving mechanism 4m moves the stage 4 in a predetermined XY 2-axis direction within a horizontal plane by the action of a driving unit (not shown). Thereby, the movement of the observation position and the movement of the laser beam irradiation position are realized. As for the moving mechanism 4m, it is more preferable for alignment and the like that the rotation (θ rotation) operation in the horizontal plane around the predetermined rotation axis can be performed independently of the horizontal drive.

  The irradiation optical system 5 includes a laser light source SL, a half mirror 51 provided in a lens barrel (not shown), and a condenser lens 52.

  In the laser processing apparatus 100, the laser light LB emitted from the laser light source SL is reflected by the half mirror 51, and then the laser light LB is placed on the stage 4 by the condenser lens 52. The work 10 is focused so as to be focused on the part to be processed, and is irradiated on the work 10. Then, by moving the stage 4 while irradiating the laser beam LB in such a manner, the workpiece 10 can be processed along a predetermined processing line. That is, the laser processing apparatus 100 is an apparatus that performs processing by scanning the laser beam LB relative to the workpiece 10.

  As the laser light source SL, an Nd: YAG laser is preferably used. As the laser light source SL, one having a wavelength of 500 nm to 1600 nm is used. Further, in order to realize the processing with the processing pattern described above, the pulse width of the laser beam LB needs to be about 1 psec to 50 psec. The repetition frequency R is preferably about 10 kHz to 200 kHz, and the laser beam irradiation energy (pulse energy) is preferably about 0.1 μJ to 50 μJ. The adjustment of the pulse width and the repetition frequency is realized by a pulse generator (not shown) provided in the laser light source SL.

  In the laser processing apparatus 100, it is possible to irradiate the laser beam LB in the defocus state in which the in-focus position is intentionally shifted from the surface of the workpiece 10 as necessary during processing. It has become. In the present embodiment, it is preferable to set the defocus value (shift amount of the focus position in the direction from the surface of the workpiece 10 to the inside) in the range of 0 μm to 30 μm.

  In the laser processing apparatus 100, the upper observation optical system 6 for observing and imaging the workpiece 10 from above is irradiated above the stage 4, and illumination light is irradiated from above the stage 4 to the workpiece 10. And an upper illumination system 7 is provided. A lower illumination system 8 for irradiating the workpiece 10 with illumination light from below the stage 4 is provided below the stage 4.

  The upper observation optical system 6 includes a CCD camera 6a provided above the half mirror 51 (above the lens barrel) and a monitor 6b connected to the CCD camera 6a. The upper illumination system 7 includes an upper illumination light source S1, a half mirror 81, and a condenser lens 82.

  The upper observation optical system 6 and the upper illumination system 7 are configured coaxially with the irradiation optical system 5. More specifically, the half mirror 51 and the condenser lens 52 of the irradiation optical system 5 are shared with the upper observation optical system 6 and the upper illumination system 7. As a result, the upper illumination light L1 emitted from the upper illumination light source S1 is reflected by the half mirror 71 provided in a lens barrel (not shown), and further passes through the half mirror 51 constituting the irradiation optical system 5, and then collected. The light is condensed by the optical lens 52 and irradiated onto the workpiece 10. In the upper observation optical system 6, the bright field image of the workpiece 10 that has passed through the condenser lens 52, the half mirror 51, and the half mirror 71 can be observed in a state where the upper illumination light L 1 is irradiated. It can be done.

  The lower illumination system 8 includes a lower illumination light source S2, a half mirror 81, and a condenser lens 82. That is, in the laser processing apparatus 100, the lower illumination light L2 emitted from the lower illumination light source S2, reflected by the half mirror 81, and condensed by the condenser lens 82 is processed through the stage 4 to the workpiece. 10 can be irradiated. For example, when the lower illumination system 8 is used, it is possible to observe the transmitted light in the upper observation optical system 6 in a state in which the workpiece 10 is irradiated with the lower illumination light L2.

  Furthermore, as shown in FIG. 1, the laser processing apparatus 100 may include a lower observation optical system 16 for observing and imaging the workpiece 10 from below. The lower observation optical system 16 includes a CCD camera 16a provided below the half mirror 81 and a monitor 16b connected to the CCD camera 16a. In the lower observation optical system 16, for example, the transmitted light can be observed in a state where the upper illumination light L <b> 1 is irradiated on the workpiece 10.

  The controller 1 controls the operation of each part of the apparatus, and refers to the control unit 2 that realizes the processing of the workpiece 10 in a mode described later, the program 3p that controls the operation of the laser processing apparatus 100, and the processing process. And a storage unit 3 for storing various data.

  The control unit 2 is realized by a general-purpose computer such as a personal computer or a microcomputer, for example, and various components can be obtained by reading and executing the program 3p stored in the storage unit 3 into the computer. Is realized as a functional component of the control unit 2.

  The storage unit 3 is realized by a storage medium such as a ROM, a RAM, and a hard disk. The storage unit 3 may be implemented by a computer component that implements the control unit 2, or may be provided separately from the computer, such as a hard disk.

  In addition to the program 3p, the storage unit 3 stores machining position data D1 describing the machining position of the workpiece 10, and each laser beam according to the mode of laser machining in each machining mode. Machining mode setting data D2 in which conditions for parameters, driving conditions for stage 4 (or their settable ranges), and the like are described is stored.

  The control unit 2 includes a drive control unit 21 that controls operations of various drive parts related to processing such as driving of the stage 4 by the moving mechanism 4m and focusing operation of the condenser lens 52, the upper observation optical system 6, An imaging control unit 22 that controls observation / imaging of the workpiece 10 by the lower observation optical system 16, an irradiation control unit 23 that controls irradiation of the laser beam LB from the laser light source SL, and the stage 4 by the suction means 11. It mainly includes a suction control unit 24 that controls the suction fixing operation of the workpiece 10 and a processing unit 25 that executes processing to the processing target position in accordance with the given processing position data D1 and processing mode setting data D2. .

  In the laser processing apparatus 100 including the controller 1 having the above-described configuration, when an operator gives an execution instruction for processing in a predetermined processing mode for the processing position described in the processing position data D1, the processing is performed. The unit 25 acquires the processing position data D1 and acquires the conditions corresponding to the selected processing mode from the processing mode setting data D2, and the drive control unit 21 and the irradiation control so that the operation according to the conditions is executed. The operation of each corresponding unit is controlled through the unit 23 and others. For example, adjustment of the wavelength and output of the laser light LB emitted from the laser light source SL, the pulse repetition frequency, the pulse width, and the like are realized by the irradiation control unit 23. Thereby, the processing in the designated processing mode is realized at the target processing position.

  Preferably, the laser processing apparatus 100 is configured such that processing modes corresponding to various processing contents can be selected according to a processing menu provided to the operator in the controller 1 by the operation of the processing unit 25. . In such a case, it is preferable that the processing menu is provided on the GUI.

  By having the above configuration, the laser processing apparatus 100 can suitably perform various laser processing.

<Principle of crack extension processing>
Next, crack extension processing that is one of processing methods that can be realized in the laser processing apparatus 100 will be described. FIG. 2 is a diagram for explaining an irradiation mode of the laser beam LB in the crack extension processing. More specifically, FIG. 2 shows the repetition frequency R (kHz) of the laser beam LB at the time of crack extension processing, and the moving speed V (mm / sec) of the stage on which the workpiece 10 is placed when the laser beam LB is irradiated. ) And the beam spot center interval Δ (μm) of the laser beam LB. In the following description, on the assumption that the above-described laser processing apparatus 100 is used, the emission source of the laser beam LB is fixed, and the stage 4 on which the workpiece 10 is placed is moved to move the workpiece. Although the relative scanning of the laser beam LB with respect to the object 10 is realized, the crack extension process is performed even when the workpiece 10 is stationary and the emission source of the laser beam LB is moved. Similarly, it is feasible.

  As shown in FIG. 2, when the repetition frequency of the laser light LB is R (kHz), one laser pulse (also referred to as unit pulse light) is emitted from the laser light source every 1 / R (msec). . When the stage 4 on which the workpiece 10 is placed moves at a speed V (mm / sec), the workpiece 10 is V × (V × () after a laser pulse is emitted and a next laser pulse is emitted. Since 1 / R) = V / R (μm), the distance between the beam center position of a certain laser pulse and the beam center position of the next laser pulse, that is, the beam spot center distance Δ (μm). ) Is determined by Δ = V / R.

From this, the beam diameter (also referred to as beam waist diameter or spot size) Db of the laser beam LB on the surface of the workpiece 10 and the beam spot center interval Δ are Δ> Db (Equation 1)
In the case of satisfying the above, the individual laser pulses do not overlap when the laser beam is scanned.

  In addition, when the irradiation time of the unit pulse light, that is, the pulse width is set to be extremely short, the irradiation position of each unit pulse light exists in a substantially central region of the irradiation position that is narrower than the spot size of the laser beam LB. The material is scattered or altered in the direction perpendicular to the irradiated surface by obtaining kinetic energy from the irradiated laser beam, while the unit pulse light including the reaction force generated by the scattering is irradiated. A phenomenon occurs in which the generated impact or stress acts around the irradiated position.

  Using these things, when laser pulses (unit pulse light) emitted one after another from the laser light source are irradiated sequentially and discretely along the planned processing line, along the planned processing line, Small processing marks are sequentially formed at the irradiation positions of the individual unit pulse lights, and cracks are continuously formed between the individual processing marks. Thus, the crack continuously formed by the crack extension process becomes a starting point of the division when the workpiece 10 is divided.

  For example, the workpiece 10 can be divided by performing a breaking process in which a crack formed by crack extension processing is extended to the opposite surface of the patterned substrate W using a known breaking device. In addition, when the workpiece 10 is completely divided in the thickness direction by the extension of the crack, the above-described breaking step is not necessary, but the workpiece is processed by the crack extension processing even if a part of the crack reaches the opposite surface. Since the object 10 is rarely completely bisected, it generally involves a break process.

  In the breaking process, for example, the workpiece 10 is placed in a posture in which the main surface on the side on which the machining marks are formed is on the lower side, and both sides of the planned dividing line (scheduled processing line) are supported by two lower break bars. In this state, the upper break bar can be lowered toward the break position on the other main surface and immediately above the planned dividing line (scheduled processing line).

  If the beam spot center interval Δ corresponding to the pitch of the machining marks is too large, the break characteristics are deteriorated and the break along the planned dividing line (scheduled line) cannot be realized. In the case of crack extension processing, it is necessary to determine the processing conditions in consideration of this point.

  In view of the above points, suitable conditions for performing crack extension processing for forming a crack to be a division starting point on the workpiece 10 are roughly as follows. Specific conditions may be appropriately selected depending on the material and thickness of the workpiece 10.

Pulse width τ: 1 psec or more and 50 psec or less;
Beam diameter Db: 1 μm or more and 10 μm or less;
Stage moving speed V: 50 mm / sec or more and 3000 mm / sec or less;
Pulse repetition frequency R: 10 kHz to 200 kHz;
Pulse energy E: 0.1 μJ to 50 μJ

<Pattern with pattern>
Next, a patterned substrate W as an example of the workpiece 10 will be described. FIG. 3 is a schematic plan view and a partially enlarged view of the substrate W with a pattern.

  The patterned substrate W is formed by laminating a predetermined device pattern on one main surface of a single crystal substrate (wafer, mother substrate) W1 (see FIG. 4) such as sapphire. The device pattern has a configuration in which a plurality of unit patterns UP each forming one device chip after being divided into pieces are repeatedly arranged two-dimensionally. For example, a unit pattern UP that becomes an optical device such as an LED element or an electronic device is two-dimensionally repeated.

  The patterned substrate W has a substantially circular shape in plan view, but is provided with a linear orientation flat (orientation flat) OF at a part of the outer periphery. Hereinafter, the extending direction of the orientation flat OF in the plane of the patterned substrate W will be referred to as the X direction, and the direction orthogonal to the X direction will be referred to as the Y direction.

  As the single crystal substrate W1, a substrate having a thickness of 70 μm to 200 μm is used. A preferred example is to use a sapphire single crystal having a thickness of 100 μm. The device pattern is usually formed to have a thickness of about several μm. The device pattern may have irregularities.

  For example, in the case of a substrate W with a pattern for manufacturing LED elements (chips), a light emitting layer and other thin film layers made of a group III nitride semiconductor such as GaN (gallium nitride) are formed on a sapphire single crystal. The electrode pattern is formed on the thin film layer, and an electrode pattern that constitutes a current-carrying electrode in the LED element (LED chip) is formed on the thin film layer.

  In forming the patterned substrate W, the plane orientation of the crystal plane such as the c-plane or the a-plane with respect to the main plane normal direction is defined as the single crystal substrate W1 with the Y direction perpendicular to the orientation flat as the axis in the main plane. A mode in which a so-called off-angle substrate (also referred to as an off-substrate) inclined by several degrees may be used.

  A narrow region that is a boundary portion of each unit pattern UP is referred to as a street ST. The street ST is a planned division position of the patterned substrate W, and the patterned substrate W is divided into individual device chips by irradiating laser light along the street ST in a manner to be described later. The street ST is usually set to have a lattice shape when the device pattern is viewed in plan with a width of about several tens of μm. However, the single crystal substrate W1 does not have to be exposed in the street ST portion, and a thin film layer forming a device pattern may be continuously formed in the street ST position. Further, the central portion of the street ST is set as the planned processing line PL.

<Division of substrate with pattern>
Next, a method for dividing the patterned substrate W performed in the present embodiment will be described.

  In the above description of the principle of crack extension processing based on FIG. 2 and the method disclosed in Patent Document 1, discrete processing traces are uniformly formed along the planned processing line. However, the method of dividing the patterned substrate W according to the present embodiment is characteristic in that the crack extension processing is intermittently performed on the planned processing line. Hereinafter, an embodiment of crack extension processing according to the present embodiment is referred to as intermittent crack extension processing, and a processing mode in which formation of discrete processing marks is uniformly performed along a planned processing line is performed as uniform crack extension. This is called processing.

  The intermittent crack extension processing according to the present embodiment is roughly the first region where the crack extension processing is performed and the processing marks are formed at equal intervals, and the crack extension processing is not performed and the processing marks are not formed. A 2nd area | region is a process aspect formed alternately along a process planned line.

  In the present embodiment, when performing intermittent crack extension processing, the surface of the patterned substrate W on which the device pattern is not provided, that is, the main surface Wa (see FIG. 4 and FIG. 5), the laser beam LB is irradiated. That is, the main surface Wb (see FIG. 5) on the side where the device pattern is formed is placed and fixed on the stage 4 of the laser processing apparatus 100 as a placement surface, and the laser beam LB is irradiated. Strictly speaking, the surface of the device pattern has unevenness, but the unevenness is sufficiently smaller than the thickness of the entire patterned substrate W, so that the device pattern of the patterned substrate W is substantially formed. It can be assumed that the formed side has a flat main surface. Alternatively, the main surface of the single crystal substrate W1 provided with the device pattern may be regarded as the main surface Wb of the patterned substrate W.

  This is not an essentially essential aspect in the implementation of intermittent crack extension processing, but when the width of the street ST is small or a thin film layer is formed up to the street ST, laser light irradiation, etc. This is a preferable mode from the viewpoint of reducing the influence of the device pattern on the device pattern or realizing more reliable division. Incidentally, in FIG. 3, the unit pattern UP and the street ST are represented by broken lines. The main surface Wa from which the single crystal substrate is exposed is the surface to be irradiated with the laser light, and the main surface Wb on which the device pattern is provided. This is to show that it faces the other side.

  FIGS. 4 and 5 are schematic views of the formation of the processing marks M on the patterned substrate W when the laser processing apparatus 100 performs intermittent crack extension processing along one processing planned line PL (PL1). FIG. 2 is a plan view of a substrate W with a pattern and a vertical cross-sectional view along the planned processing line PL (PL1).

  When intermittent crack extension processing is performed along one processing planned line PL, as shown in FIGS. 4 and 5, the first region RE1 in which a plurality of processing marks M are discretely formed at equal intervals and The second regions RE2 in which no processing trace is formed are alternately formed along the planned processing line. In other words, the first regions RE1 where the processing marks are formed are unevenly distributed along the planned processing line PL at equal intervals. Alternatively, the unit region RE in which the first region RE1 and the second region RE2 are combined is repeated. Note that the crack extension processing in the first region RE1 is performed under conditions that allow the patterned substrate W to be suitably broken by a subsequent break when the uniform crack extension processing is performed along the planned processing line PL.

  In such a case, cracks extend between the individual processing marks M in the first region RE1 or below the processing marks M. On the other hand, the crack does not necessarily extend in the second region RE2. In other words, by performing intermittent crack extension processing along one planned processing line PL, in the patterned substrate W, the regions where crack growth has occurred and the regions where no cracks have occurred alternate along the processing planned line PL. Will be repeated.

  And the board | substrate W with a pattern of such a state is used for a break apparatus, and the break along the said process plan line PL is performed. In such a case, cracks extend from each first region RE1 where crack extension occurs to the opposite surface Wb of the patterned substrate W and between the first regions RE1, and the pattern is attached. The substrate W is divided along the planned processing line. That is, the patterned substrate W can be favorably divided in spite of including the second region RE2 where the processing mark M does not exist. Thereby, the substrate W with a pattern is divided | segmented in the aspect which has a process cross section like the vertical cross section illustrated in FIG. That is, if intermittent crack extension processing is performed along the planned processing line PL, the patterned substrate W can be divided along the planned processing line PL.

  Preferably, in the intermittent crack extension processing, the size T of the unit pattern UP in the direction along the planned processing line to be processed is set so that the size t1 of the first region RE1 and the second region RE2 in the direction along the planned processing line PL. This is an integral multiple of the sum of the sizes t2 (that is, the size of the unit region RE), and the size ratio t2 / t1 is 20/80 or more and 60/40 or less. 4 and 5 exemplify a case where the size T is four times t1 + t2, that is, T = 4 (t1 + t2). However, in the present embodiment, the size t1 of the first region RE1 is a center-to-center distance between the processing marks M existing at both ends of the first region RE1, as shown in FIGS.

  By satisfying these requirements, the patterned substrate W along the planned processing line PL can be more favorably divided. More specifically, t1 = (k−1) Δ, where k is the number of all machining marks M discretely present in the first region RE1 (k is a natural number). Further, as shown in FIGS. 4 and 5, the size of the second region RE2 is a processing mark located at a location closest to the second region RE2 in each of the two first regions RE1 adjacent to the second region RE2. It is assumed that the distance is between M.

  Further, it is more preferable to perform intermittent crack extension processing so that the formation pitch of the processing mark M in the first region RE1, that is, the beam spot center interval Δ is 5 μm or less, and the size t2 of the second region RE2 is 100 μm or less. preferable. If the former is not observed, the crack extension process itself is not performed, which is not preferable. If the latter is not observed, the break cannot be performed well along the planned processing line (division planned line), which is not preferable.

  Regarding the formation pitch of the machining marks M, when the formation pitch of the machining marks M in the uniform crack extension processing and the formation pitch of the processing marks M in the first region RE1 of the intermittent crack extension processing are the same. In the intermittent crack extension process, the number of processing marks M formed is smaller than the uniform crack extension process by the presence of the second region RE2. Therefore, for example, when dividing the patterned substrate W in which unit patterns of optical devices such as LED elements are repeatedly formed to obtain LED elements, intermittent crack extension processing is performed on the divided LED elements. However, the light extraction efficiency is higher than that of the LED element divided by performing uniform crack extension processing. That is, it can be said that the intermittent crack extension processing is a preferable processing technique for increasing the light extraction efficiency of the LED element.

  By the way, from the viewpoint of reducing the number of processing marks to be formed, a mode in which the beam spot center interval of the laser beam LB corresponding to the formation pitch of the processing marks in the uniform crack extension processing is also considered. For example, FIG. 6 shows a processing mark M when a uniform crack extension processing is performed on the patterned substrate W illustrated in FIGS. 4 and 5 at a beam spot center interval Δ ′ having a value larger than Δ. It is a top view which shows the mode of formation of. However, it is assumed that 5 μm <Δ ′ <t2. Further, it is assumed that the number of processing marks M per substrate size T is the same.

  In the case of intermittent crack extension processing, the crack CR also extends in the second region RE2 at the time of break after crack extension processing. Therefore, in the case of FIG. 6 where Δ ′ <t2, the crack extension processing is also performed. It is expected that the crack CR suitably extends between the machining marks M during the subsequent break. However, in the case of such an embodiment, it has been confirmed by the inventor of the present invention that the break after the crack extension processing cannot always be performed satisfactorily. Here, if the break cannot be performed satisfactorily, the extension of cracks in the break process does not proceed along the planned processing line, and the LED element breaks diagonally, or in the first place, breaks occur under general break conditions. This is not possible, and it means that some trouble occurs in the break, such as an excessive load applied to the break bar and the break bar is broken.

  The reason for this is that in the case of intermittent crack extension processing, at least in the first region RE1, cracks are sufficiently extended at the time before the breaking step and weakened in strength, whereas the interval between the processing marks M is increased. In the case of uniform crack extension processing with a widening, the crack CR is not always connected between the processing marks M before the break, resulting in a higher load in the break process than in the case of intermittent crack extension processing. This is thought to be because of

  This is because, as in the present embodiment, in the first region RE1 where the processing mark M is formed, the crack extension is surely generated between the processing marks M, and the second region where the processing mark M is not formed. It means that it is important to form RE2 intermittently to achieve a good break while suppressing the number of machining marks M.

  In addition, when dividing the substrate W with a pattern, as shown in FIG. 4, it is necessary to perform a break along the planned processing lines PL1 and PL2, which are orthogonal to each other. When the process is to be performed, the process planned line PL1 and the process planned line PL2 intersect with each other (the process planned line intersecting position) is formed at the time of intermittent crack extension processing along the process planned lines PL1 and PL2. It is preferable that the first regions RE1 intersect each other. In such a case, a good break can be realized without causing any chipping or cracking in the LED element. For example, FIG. 4 shows a state where the first region RE1 is formed at the crossing position of the planned processing line in the intermittent crack extension processing along the planned processing line PL1. In such a case, the first region RE1 may be formed at the crossing position of the planned processing line also in the subsequent intermittent crack extension processing along the planned processing line PL2.

  As described above, according to the present embodiment, when dividing the patterned substrate along the planned processing line, the first region where the crack extension process is performed and the processing marks are formed at equal intervals, In addition, by performing intermittent crack extension processing that alternately forms the second region where the crack extension processing is not performed and the processing trace is not formed along the planned processing line, the division starting point is formed on the patterned substrate. By performing the break along the planned processing line, the patterned substrate can be divided well while reducing the number of processing marks as compared with the case of performing the conventional uniform crack extension processing. Thus, for example, in the case where a substrate with a pattern in which unit patterns of optical devices such as LED elements are repeatedly formed is divided into individual LED elements (LED chips), the light from inside the element is transmitted. Since the number of processing traces that obstruct the emission is smaller than in the past, an LED element with improved light extraction efficiency than in the prior art can be obtained.

DESCRIPTION OF SYMBOLS 1 Controller 2 Control part 3 Memory | storage part 3p Program 4 Stage 4m Moving mechanism 5 Irradiation optical system 6 Upper observation optical system 6a Camera 6b Monitor 7 Upper illumination system 8 Lower illumination system 10 Work piece 10a Holding sheet 11 Suction means 16 Lower observation optical System 16a Camera 16b Monitor 21 Drive control unit 22 Imaging control unit 23 Irradiation control unit 24 Adsorption control unit 25 Processing unit 51 Half mirror 52 Condensing lens 71 Half mirror 81 Half mirror 82 Condensing lens 100 Laser processing apparatus CR Crack D1 Processing Position data D2 Processing mode setting data LB Laser light M Processing mark OF Orientation flat PL (PL1, PL2) Planned processing line SL Laser light source ST Street T (of substrate with pattern) UP Unit pattern W Substrate with pattern W1 Single crystal base

Claims (6)

A method of processing a substrate with a pattern in which a plurality of unit patterns are repeatedly arranged two-dimensionally on a single crystal substrate,
A split starting point forming step of forming a split starting point on the patterned substrate by irradiating laser light along a planned processing line set on the patterned substrate;
A breaking step for breaking the patterned substrate into pieces by breaking along the division starting points;
With
In the division starting point forming step, the processing mark formed on the patterned substrate by each unit pulse light of the laser light is irradiated by scanning the laser light along the planned processing line. A crack extension processing step for causing cracks to extend from the respective processing marks to the substrate with the pattern while being discretely positioned along the line,
Including
In the split starting point forming step, a first region in which the processing marks are formed at equal intervals by performing the crack extension processing step, and a second region in which the crack extension processing step is not performed and the processing marks are not formed. And the crack extension processing step is intermittently performed along the planned processing line so that the regions are alternately formed along the planned processing line.
A method for processing a substrate with a pattern. It is a processing method of the board | substrate with a pattern of Claim 1, Comprising:
The size of the unit pattern in the direction along the planned processing line is an integer multiple of the sum of the size of the first region and the size of the second region in the direction along the planned processing line;
The ratio of the size of the second region to the size of the first region in the direction along the planned processing line is 20/80 or more and 60/40 or less,
A method for processing a substrate with a pattern. It is a processing method of the board | substrate with a pattern of Claim 2, Comprising:
In the direction along the planned processing line, the interval between the processing marks in the first region is 400 μm or less, and the size of the second region is 100 μm or less.
A method for processing a substrate with a pattern. It is a processing method of the board | substrate with a pattern of Claim 2 or Claim 3, Comprising:
The first processing line and the second processing line that are perpendicular to each other,
In the split starting point forming step, the crack extension processing step is performed such that the first region in the first processing line and the first region in the second processing line intersect.
A method for processing a substrate with a pattern. A method of processing a substrate with a pattern in which a plurality of unit patterns are repeatedly arranged two-dimensionally on a single crystal substrate,
A split starting point forming step of forming a split starting point on the patterned substrate by irradiating laser light along a planned processing line set on the patterned substrate;
A breaking step for breaking the patterned substrate into pieces by breaking along the division starting points;
With
In the division starting point forming step, the processing mark formed on the patterned substrate by each unit pulse light of the laser light is irradiated by scanning the laser light along the planned processing line. A crack extension processing step for causing cracks to extend from the respective processing marks to the substrate with the pattern while being discretely positioned along the line,
Including
In the split starting point forming step, the crack extension processing step is performed in such a manner that regions where the processing marks are formed are unevenly distributed along the planned processing line by performing the crack extension processing step. Intermittently along the planned line,
A method for processing a substrate with a pattern. An apparatus for processing a substrate with a pattern in which a plurality of unit patterns are repeatedly arranged two-dimensionally on a single crystal substrate,
A split starting point forming means for forming a split starting point on the patterned substrate by irradiating a laser beam along a planned processing line set on the patterned substrate;
Break means for breaking the patterned substrate into pieces by breaking along the division starting points;
With
When the division start point forming unit irradiates the laser beam while scanning along the planned processing line, a processing mark formed on the patterned substrate by each unit pulse light of the laser light is scheduled to be processed. Crack extension means for extending the cracks from the respective processing traces to the patterned substrate while being discretely positioned along the line;
Including
The dividing start point forming means includes a first area where the processing marks are formed at equal intervals by the crack extension processing means and a second area where the processing marks are not formed alternately along the planned processing line. Is a means for causing the crack extension processing to be performed intermittently along the planned processing line,
An apparatus for processing a substrate with a pattern.

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