TW201334904A - Splitting method of processed object and splitting method of substrate having optical element pattern - Google Patents

Abstract

This invention provides a splitting method of a brittle material processed object with high precision and high efficiency. The splitting method of a processed object comprises the following steps: irradiating a first laser beam to a scribed surface of the processed object to form a scribed line on the scribed surface; irradiating a second laser beam along the scribed line from a non-scribed surface to heat the processed object along the scribed line; and in the subsequent steps, using the second laser beam to perform relative scanning with the scribed surface being in contact with a cooling medium so as to move and cool down a tensile stress field formed in the processed object and adjacent to the scribed line. Therefore, cracks from the scribed line toward the non-scribed surface generated due to the scribed line within the tensile stress field are allowed to progress along the scribed line sequentially for splitting the processed object.

Description

Method for breaking workpiece and method for breaking substrate with optical element pattern

The present invention relates to a method of breaking a workpiece by irradiating laser light.

As a method of processing a hard and brittle material (brittle material) such as a glass plate or a sapphire substrate, various methods are known. For example, as a processing of a glass plate, a method of forming a shallow scratch (initial crack) in a line shape from the end portion of a material to be cut, such as a crystal of diamond, is known, and the so-called drawing is performed. A force is applied to both sides of the initial crack formed to advance the initial crack in the thickness direction, thereby breaking the glass sheet.

However, in the case of such a method, when the breaking operation is performed, the inclination is generated in the sectional section or the direction is unexpectedly broken according to the depth of the drawn line or the direction in which the force is applied, etc., and the desired result cannot be obtained. Breaking accuracy, in the worst case, there is also the risk of damage to the entire material.

Further, it is known that a method is provided in which an initial crack is applied to an end portion of a workpiece and a heating scan by laser light is applied from the end portion, whereby the crack progresses and the workpiece is separated (for example, reference) Patent Document 1).

In the case of such a method, if the brittle material as the breaking target is homogeneous and the generated stress field is an ideal stress field, there is a possibility that the position or direction of the crack progress can be controlled with high precision, but In reality, it is difficult to control the progress of cracks with high precision in terms of material inhomogeneity, heterogeneity of heating energy distribution, or difficulty in position control of high-precision heating points. The high precision mentioned here is assumed to be accurate in the order of μm. Position control.

In addition, in the crack growth progress control, it is necessary to limit the processing order or the process of dare to stagger the heating point, for example, in the case where stress dispersion occurs at the end portion of the workpiece and the stress distribution becomes uneven. Literature 2).

In addition, when a brittle material in which a unit pattern is two-dimensionally arranged is cut out into a single piece (wafer unit) per unit pattern, two of them are orthogonal to each other by laser cutting. In the case of cutting out in the direction, after cutting in a certain direction, cutting is performed in a direction orthogonal to the direction, but in the case of processing a large amount of wafers, the method of imparting initial cracks is changed. It is more complicated.

As a combination of the above methods, there is also known a method of providing a minute flaw (initial crack) on the end of a hard and brittle material substrate (for example, glass, enamel, ceramic, sapphire, etc.) by using a diamond or a Vickers indenter. Thereafter, a laser light absorbing material is disposed on the back surface side of the substrate, and the back surface of the substrate is locally heated by the focused laser irradiation, and the stress is concentrated to cause the crack to progress to separate the glass (for example, reference) Patent Document 3).

Alternatively, it is also known that a method of applying a line-like processing mark called a drawing line or a scribe line to a surface of a workpiece or a laser beam by irradiation of a laser beam in advance is used. When the irradiation of the light is heated, the crack is progressed from the processing mark, and the workpiece is separated (for example, refer to Patent Document 4 and Patent Document 5).

Further, in Patent Document 3, a form in which a laser beam is irradiated from a surface opposite to the line to be cut is also disclosed.

Further, it is known that the light-emitting efficiency is improved by providing irregularities on the side surface of the light-emitting element by dry etching (for example, see Patent Document 6).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Special Fair No. 3-13040

[Patent Document 2] Japanese Patent Laid-Open No. Hei 9-45636

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2008-62547

[Patent Document 4] Japanese Patent No. 2712723

[Patent Document 5] Japanese Patent No. 3036906

[Patent Document 6] Japanese Patent No. 3852000

In the case of the method disclosed in Patent Document 3, the direct heating by the laser light is ultimately classified as a laser light absorbing material, and the hard and brittle material substrate is indirectly heated only by heat conduction from the laser light absorbing material. Therefore, it is difficult to ensure the uniformity of heat conduction, and the tensile stress does not necessarily act in the direction in which the action is intended. Further, similarly to the conventional laser cutting as disclosed in Patent Document 1, it is difficult to control the progress direction of the crack. Therefore, it is difficult to perform high-precision breaking by such a method.

Further, in Patent Document 4 and Patent Document 5, the basic principle of breaking the workpiece by irradiating the laser light with a machining mark formed by mechanical or laser light is sufficient, and such a division is performed efficiently. The method of breaking is not disclosed or implied.

Further, Patent Document 6 discloses that the light extraction efficiency is improved by performing the uneven processing on the side surface of the semiconductor film of the light-emitting element. However, the processing of the sapphire wafer as the substrate is not disclosed. When the sapphire substrate is subjected to the concavo-convex processing by the method disclosed in Patent Document 6, it is necessary to perform the resist coating treatment again, and the etching itself takes time, so that there is a problem that the productivity is low.

The present invention has been made in view of the above problems, and an object thereof is to provide a technique for cutting a workpiece including a brittle material with high precision and high efficiency. Further, in particular, when a substrate having a pattern in which a light-emitting element pattern is two-dimensionally formed on a surface is a workpiece, it is possible to simultaneously improve the light-emitting element in addition to the high-precision and high-efficiency processing. The technology of efficiency.

In order to solve the above problems, the invention of claim 1 is characterized in that it is a method of dividing a workpiece, and includes a scribing processing step of causing the first laser light to be emitted from the first emission source and The scribing surface of the processed object is irradiated with the first laser light, and a scribing line is formed on the scribing surface; and an irradiation heating step is performed by ejecting the second laser light from the second ejecting source and from the scribing surface The opposite surface, that is, the non-scribe surface side, irradiates the second laser light along the scribe line, and the workpiece is heated along the scribe line; and in the irradiation heating step, the scribe line is caused by a second laser light is scanned relative to the scribe line while the workpiece is placed on the cooling medium in contact with the cooling medium, and the second laser light is directed to the non-scribe line Surface illumination The inside of the workpiece on the scribe line is moved and cooled by the tensile stress field in the vicinity of the scribe line, thereby causing the scribe line to be located in the tensile stress field from the scribe line The progress of the cracks on the non-lined surface is sequentially generated along the above-mentioned scribe lines, thereby breaking the above-mentioned workpiece.

According to a second aspect of the invention, in the illuminating and heating step, after the irradiation range of the second laser light emitted from the second emission source is adjusted by an adjustment mechanism, The second laser light is irradiated onto the non-line surface.

The invention of claim 3 is the method according to the first aspect or the second aspect, characterized in that the second laser light is a CO ₂ laser.

The invention of claim 4 is characterized in that, in the step of irradiating and heating, the second laser light is irradiated in a pulse oscillation mode to form a single sheet formed by dividing the workpiece. On the divided sections of the sheet, an undulation for reducing the total reflectance with a period corresponding to the pulse oscillation period is generated.

The invention of claim 5 is the method of dividing the first aspect or the second aspect, characterized in that the first laser light YGA (Yttrium Aluminum Garnet) is a triple harmonic of the laser.

The invention of claim 6 is characterized in that the method further comprises an alignment processing step of correcting a posture in a horizontal plane of the workpiece; and The object to be processed in the processing step performs the scribing processing step and the irradiation heating step.

The invention of claim 7 is the breaking side of the technical solution 1 or the technical solution 2 In the above-described scribing processing step, the scribing is performed by melting and re-solidifying the irradiated position of the first laser light to cause the irradiated position to become a modified region.

The invention of claim 8 is characterized in that, in the step of scribing, the ablation is caused by the position of the first laser beam being irradiated. The grooved portion is formed at the irradiated position to form the scribe line.

The invention of claim 1 is the method according to the first aspect or the second aspect, wherein the plurality of lines are formed in the first direction and the second direction orthogonal to each other. And in the irradiation heating step, after the irradiation of the scribe line extending from the non-scribe surface side along the first direction is performed, the step of extending along the second direction is performed. The line is heated by irradiation.

The invention of claim 9 is characterized in that, in the illuminating and heating step, the diameter of the irradiation beam of the second laser beam is set to be equal to or less than a distance between the scribe lines.

The invention of claim 11 is characterized in that it is a method of dividing a substrate having an optical element pattern in which an optical element pattern is two-dimensionally formed on the surface, and includes: a scribing processing step by making the first laser light from the first 1 emitting source, irradiating the first laser light on the scribe line surface of the substrate having the optical element pattern, forming a scribe line on the scribe line surface; and irradiating the heating step to make the CO ₂ laser, ie, the second ray The emitted light is emitted from the second emission source, and the second laser light is irradiated from the scribing surface side along the scribe line, and the substrate having the optical element pattern is heated along the scribe line; and the irradiation heating step is performed By scanning the second laser light relative to the scribe line, the substrate having the optical element pattern is formed on the substrate around the illuminating heating region by the irradiation of the second laser light. The tensile stress field is moved, whereby the progress of the crack from the scribe line to the non-scribe surface due to the scribe line being located in the tensile stress field is sequentially generated along the scribe line, thereby dividing The substrate having the optical element pattern and the second laser light emitted in a pulse oscillation mode are formed on a cross section of the optical element monolith formed by dividing the workpiece to generate a pulse and a pulse The total reflectance of the period corresponding to the oscillation period is reduced by the fluctuation.

According to the inventions of the first aspect to the eleventh aspect, the second laser light is irradiated along the scribe line formed in advance at the predetermined breaking position of the workpiece by the irradiation of the first laser light, thereby heating the workpiece. The tensile stress acts on the scribe line, so that the progress of the crack from the scribe line to the non-scribe surface is sequentially generated along the extending direction of the scribe line, whereby the workpiece can be separated with high precision. Further, since the progress of the crack is more efficiently generated by irradiating the non-line surface with the second laser light, the high-precision division can be performed with high efficiency.

In particular, according to the inventions of claim 4 and claim 11, the undulations can be purposefully generated on the cross-section of the object to be separated. Thus, for example, a substrate for LED manufacturing, which is a sapphire substrate in which an LED (Light Emitting Diode) pattern is two-dimensionally formed on the surface, is a dividing object, and the substrate is divided into LED wafer units. In the case of a single piece, it can be suppressed Total reflection on the cross-section of the LED chip to improve the luminous efficiency of the LED chip.

<Basic Principles of Processing>

First, the basic principle of the processing (breaking processing) of the present embodiment will be described. The cutting process performed in the present embodiment is substantially as follows: after the first laser light (the laser light for scribing) is irradiated to the predetermined breaking position of the workpiece (the object to be separated) W, the scribe line SL is formed. By applying heat by the irradiation of the second laser light (laser light for heating) (laser heating), a stress field is generated in the vicinity of the scribe line SL, whereby cracks (cracks) are used as initial cracks. The scribing SL begins to progress, and the processed object is broken.

The workpiece W is, for example, a brittle material such as a glass plate or a sapphire substrate, or a substrate in which a unit pattern is two-dimensionally formed on a surface of a substrate including the brittle material by a film layer or the like (hereinafter, A substrate having a pattern) or the like.

Fig. 1 is a view schematically showing a state in the middle of the breaking process performed in the embodiment. More specifically, FIG. 1 shows a case where laser heating is performed by irradiating the heating laser light LBh along the scribe line SL formed in advance on the workpiece W.

In the following description, the surface on which the scribe line SL is formed in the workpiece W or the surface on which the scribe line SL is to be formed is referred to as a scribe line W1, and the opposite side of the scribe line W1 is referred to as a non-pattern. Line surface W2. In addition, FIG. 1 shows a case where the scribing surface W1 is scanned by moving the heating laser light LBh in the scanning direction indicated by the arrow AR1 (which may of course be the extending direction of the scribe line SL), but In place of this, the heating laser light LBh may be fixedly irradiated to a certain irradiation position, and the workpiece W may be moved by a moving mechanism (not shown). The illuminating light LBh achieves a relative scanning in the direction of the arrow AR1.

When the heating laser light LBh is irradiated, the irradiation region of the heating laser light LBh in the scribing surface W1 of the workpiece W is heated and expanded, and as shown in FIG. 1, the compressive stress field SF1 is obtained. On the other hand, the outer peripheral region of the compressive stress field SF1 contracts to become the tensile stress field SF2. When the scribe line SL is included in the tensile stress field SF2, the tensile stress TS acts on the side of the scribe line SL in the workpiece W. The crack CR progresses from the scribe line SL to the predetermined breaking position L0 on the non-scribe line surface W2 side by the action of the tensile stress TS. Further, as described above, since the heating laser light LBh is relatively scanned along the scribe line SL, the tensile stress field SF2 also moves along the scribe line SL. Then, the portion where the crack CR progresses toward the non-scribe line surface W2 side migrates along the extending direction of the scribe line SL, that is, the scanning direction of the heating laser light LBh. Therefore, when the heating laser light LBh is irradiated from one end to the other end of the scribe line SL provided at the predetermined breaking position on the side of the scribe line W1, the crack CR can be sequentially generated at the entire forming position of the scribe line SL. The progress of the position L0 is broken, and as a result, the workpiece W can be separated. This is the basic principle of the breaking process of the embodiment.

When the workpiece W is cut in such a manner, after the workpiece W is accurately positioned, the scribing SL formed at a specific position on the scribing surface W1 with high precision is set as the initial crack. The crack CR is progressed toward the non-line surface W2 side. Generally, the thickness of the workpiece W is different from the length of the scribe line SL. Often small, and since the tensile stress field SF2 formed by the heating laser light LBh is relatively uniform, the offset of the breaking position is less likely to occur. That is, in the present embodiment, it is possible to perform the breaking with excellent precision. As a result, the division with an accuracy of μm level can be achieved.

In addition, when a substrate having a pattern such as a sapphire substrate in which an LED pattern is formed two-dimensionally on the surface, which is a substrate for LED production, is divided into a single piece (wafer unit) per unit pattern, the predetermined portion is cut off. When the position is set to a lattice shape, a plurality of lines SL are sequentially formed in the first direction and the second direction orthogonal to each other, and then heating by the heating laser light LBh is sequentially performed for each direction. In this case, if the laser beam LBh is heated to perform laser heating along a scribe line SL (first scribe line) extending in the first direction, another scribe line SL orthogonal thereto is used. In the vicinity of the lattice point of the (second scribe line), the crack CR also partially slightly progresses toward the non-scribe line surface W2 on the second scribe line extending in the second direction. However, in such a case, by performing laser heating along the second scribe line, it is also possible to perform the problem of no precision problem.

The laser beam for scribing may be used by selecting appropriate pulsed laser light depending on the material of the workpiece W or the like. For example, when the sapphire substrate or the substrate for LED production, which is a patterned substrate made of a sapphire substrate, is the workpiece W, it is preferable to use a YAG laser 3 times higher harmonic (wavelength 355). Nm). Further, in order to improve the breaking accuracy and the reliability at the predetermined breaking position, it is preferable to form the scribe line SL as thin as possible, so that the laser light for scribing is irradiated in an irradiation range of several μm to several tens of μm ( Irradiation is performed within the diameter of the illumination beam. Further, in terms of processing efficiency (energy use efficiency), the laser light for scribing is in the vicinity of the scribing surface W1 of the workpiece W or the inner scribing surface W1 (from the scribing surface W1 to several tens of μm) Range up to the left and right). Further, in the present embodiment, the irradiation beam diameter refers to a case where the energy distribution of the section of the laser beam irradiated is assumed to have a Gaussian distribution shape, and the energy value is 1/e ² or more of the highest value of the center. The diameter of the area.

Further, the scribe line SL may be a shape in which a groove formed by evaporating a position of the laser light for scribing is formed into a triangular shape or a wedge shape as a scribe line SL, or The deformed region in which the triangular or wedge-shaped shape is observed as a cross section formed by melting and resolidifying (melting and modifying) the material at the position to be irradiated is a scribe line SL. The irradiation conditions (pulse width, repetition frequency, peak power density, scanning speed, etc.) of the laser light for scribing are determined depending on which form is adopted. In addition, although the case where the scribe line SL is continuously formed is illustrated in FIG. 1, the formation form of the scribe line SL is not limited to this. For example, the form of the scribe line SL may be formed in a dotted line or a dotted line along a predetermined breaking position.

On the other hand, as the heating laser light LBh, a long-wavelength laser, that is, a CO ₂ laser (wavelength of 9.4 μm to 10.6 μm) is preferably used. Since the CO ₂ laser is surely absorbed on the surface of the glass or sapphire, the progress of the crack CR from the scribe line SL can be surely produced. Further, the laser beam for irradiation for the purpose of processing the so-called workpiece formed by the scribe line SL is different from the laser light for the scribe line, and the heating laser light LBh is a compressive stress formed in the heating region by heating the workpiece. The laser light irradiated for the purpose of stretching the stress field SF2 is formed around the field SF1. Therefore, when the workpiece is not broken or deteriorated, or when the tensile stress field SF2 is formed as wide as possible, the irradiation range of the heating laser light LBh is larger than the laser light for scribing. For example, when the thickness of the workpiece is 150 μm, it may be about 100 μm to 1000 μm.

However, when a rectangular shaped wafer is cut out from a patterned substrate, the irradiation beam diameter of the heating laser light LBh is set to be the same as the planar size of the wafer (substantially the same as the predetermined breaking position) or It is below. When the diameter of the irradiation beam is made larger than the plane size of the wafer, a case where the wafer cannot be well cut and a specific shape cannot be obtained is disadvantageous.

<Relationship between the oscillation mode of the laser light for heating and the shape of the sectional section>

For example, when a CO ₂ laser is used as the heating laser light LBh, the heating laser light LBh can be irradiated in the two oscillation modes of the continuous oscillation mode and the pulse oscillation mode. Further, according to the oscillation mode, it is confirmed that the shape of the cross-section of the workpiece W is different. Specifically, in the case of the continuous oscillation mode, the section formed by the progress of the crack becomes a very smooth flat surface. On the other hand, in the case of the pulse oscillation mode, periodic fluctuations (concavities and convexities) corresponding to the pulse oscillation period are formed on the cross-section. 2 is an SEM (Scanning Electron Microscope) image of a cross section when a sapphire substrate is separated by using a CO ₂ laser as the heating laser light LBh. In the figure, "Fracture surface" is a cross-section, Groove is a scribing line, and "Feed direction" is the moving direction of the sapphire substrate (the opposite direction of the scanning direction of the laser light) . In the case shown in Fig. 2, although the cross-section is transparent, it is formed with undulations at intervals of several tens of μm. In general, it is preferable that the cross-section of the workpiece W is a flat surface. Therefore, in many cases, the irradiation of the heating laser light LBh is performed in a continuous oscillation mode.

On the other hand, it is preferable to have a situation in which the undulation is purposefully (positively) generated on the sectional section. For example, a sapphire substrate (wafer) in which an LED (light-emitting element) pattern is two-dimensionally formed, that is, a substrate for manufacturing an LED, is a workpiece W, and the substrate is divided into individual pieces of LED wafer units. situation. Fig. 3 is a view showing the difference in the forward direction of the light in the cross-section when the split surface is flat and the undulation is present on the flat surface.

In general, a light-emitting element (LED wafer) is required to illuminate the light emitted from the light-emitting element construction portion provided on the substrate as much as possible without being blocked. Since a part of such light is also incident on the substrate portion, in order to improve the luminous efficiency (light efflux efficiency) of the light-emitting element, it is necessary to transmit the emitted light as much as possible in the substrate portion. On the other hand, when light is advanced from a medium having a large refractive index to a medium having a small refractive index, light incident at a critical angle θ _c or more with respect to the interface (incidence surface) is totally reflected. Optical limitations (Snell's Law). For example, when light travels from sapphire to air, θ _c = 34.4°.

When the cross-section is a flat surface, as shown in FIG. 3(a), all of the light incident on the cross-section at an incident angle of a critical angle θ _c or more is reflected by the light generated in the light-emitting element portion. Further, in theory, according to the traveling direction after the generation, total reflection is continuously suffered, and as a result, light which is enclosed in the inside of the LED wafer is also generated. As described above, when light is advanced from the sapphire to the air, it is in accordance with this case that the light is incident on the cross-section at an incident angle of 34.4 or more and 55.6 or less.

On the other hand, when there is a undulation in the cross-section, as shown in FIG. 3(b), even if light incident from the same direction as in the case of FIG. 3(a), the incident angle is based on the incident position. Less than that of Fig. 3(a), a component that transmits through the cross section is produced. Moreover, even if a certain section is reflected, the probability of passing through different sections will become higher. That is, the ratio (total reflectance) at which the light incident to the cross-section is totally reflected in the cross-section can be reduced. Therefore, in the case where the section has an undulation, it is easy to pluck the state of the light generated compared to the case where the section is a flat surface. Further, in the actual light-emitting element, the substrate of the LED chip is not necessarily directly exposed to the outside, and may be sealed by a resin. However, even in such a case, the above effects are obtained in the same manner.

In the case where the workpiece W is a substrate for LED production and the substrate is divided into LED wafer units, the heating laser light LBh is irradiated in a pulse oscillation mode to cause undulations in the cross-section. Make a break. Thereby, an LED wafer with high light extraction efficiency can be obtained. Such a method can form an undulation at the same time as the breaking of the workpiece W, and thus is a method of high efficiency and high productivity as compared with a method of forming irregularities by dry etching as disclosed in Patent Document 6, for example.

<breaking device>

Next, based on the above-described processing principle, a breaking device that performs the breaking of the workpiece will be described. FIG. 4 is a view schematically showing the configuration of the breaking device 100.

As shown in FIG. 4, the breaking device 100 mainly includes a stage portion 10, a laser optical system 20 for scribing, a laser optical system 30 for heating, and position reading light. Learning system 40. Further, the breaking device 100 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown). The control system 50 includes various signals transmitted between the laser optical system 20 for scribing, the laser optical system 30 for heating, and the position reading optical system 40, thereby controlling the operation of each component. Further, the control system 50 may be incorporated into the main body of the breaking device 100 as being integrated with other components, or may be provided separately from the main body of the breaking device 100, for example, including a personal computer or the like. .

The stage unit 10 mainly includes an XY stage 11 and a processing stage 12 provided on the XY stage 11.

The XY stage 11 is freely movable in two directions (X direction, Y direction) orthogonal to each other in the horizontal plane (in the XY plane) based on the drive control signal sg1 from the control system 50. Furthermore, the position information signal sg2 of the XY stage 11 is continuously fed back to the control system.

The processing stage 12 is a portion for placing and fixing the workpiece W thereon. The processing stage 12 includes an adsorption mechanism (not shown), and is configured such that the suction mechanism is actuated by the adsorption control signal sg3 from the control system 50, and the workpiece W is adsorbed and fixed to the processing load. The upper surface 12a of the stage 12. Further, the machining stage 12 includes a rotation drive mechanism (not shown), and can also perform a rotation operation in a horizontal plane based on the rotation control signal sg4 from the control system 50.

In addition, although illustration is abbreviate|omitted in FIG. 4, it is the following aspect. When the processing stage 12 is fixed, an adhesive film is attached to the non-scribe surface W2 side (the mounting surface side) of the workpiece W, and the workpiece W is fixed together with the film.

The scribing laser optical system 20 is a portion that irradiates the workpiece W with the laser light for scribing based on the scribing laser control signal sg5 supplied from the control system 50.

Fig. 5 is a view showing a detailed configuration of the laser optical system 20 for scribing. As shown in FIG. 5, the laser optical system 20 for scribing mainly includes a laser oscillator 21 as a light source (exit source) for laser light LBs for scribing, and an attenuator 22 for performing self-laser oscillation. The line drawn by the device 21 is adjusted by the amount of light of the laser light LBs; and the objective lens 23 is used for adjusting the focus of the laser light LBs for scribing. In addition, as described above, since the laser light corresponding to the material of the workpiece W or the like is used as the laser light LBs for scribing, the laser oscillator 21 is used only for the type of the laser light LBs to be used for the scribing. Just choose.

Further, the laser optical system 20 for scribing also includes a mirror 24 for appropriately changing the optical path direction of the scribing laser light LBs by reflecting the laser light LBs. Further, although the case where only one mirror 24 is included is illustrated in FIG. 5, the number of the mirrors 24 is not limited thereto, and the inside of the laser optical system 20 according to the scribing or the layout according to the inside of the breaking device 100 is used. For the requirements and other reasons, it is also possible to provide more mirrors 24 and appropriately set the optical path of the laser light LBs for scribing.

More specifically, in the laser oscillator 21, a shutter 21a for switching the non-exiting of the laser light LBs for scribing is provided. Switching of shutter 21a The control is performed based on the ON/OFF control signal sg5a which is one of the scribing laser control signals sg5. Further, the adjustment of the amount of light of the scribing laser light LBs in the attenuator 22 is controlled based on the output power control signal sg5b which is one of the scribing laser control signals sg5.

In the laser optical system 20 for scribing, the laser light LBs emitted from the laser oscillator 21 and adjusted by the attenuator 22 for the amount of light is applied to the scribing surface W1 of the workpiece W or the inner scribing surface W1. In the vicinity (the range from the scribe line W1 to the range of several tens of μm), the arrangement position of the objective lens 23 is adjusted such that the diameter of the irradiation beam is several μm to several tens of μm. Thereby, a good scribe line SL is formed.

The heating laser optical system 30 is a portion that irradiates the workpiece W with the laser light for heating based on the heating laser control signal sg6 supplied from the control system 50.

Fig. 6 is a view showing a detailed configuration of the heating laser optical system 30. As shown in FIG. 6, the heating laser optical system 30 mainly includes a laser oscillator 31 as a light source (output source) for heating the laser light LBh, and an attenuator 32 for performing the self-laser oscillator 31. The amount of light for the heating laser light LBh for emission is adjusted; the beam adjusting mechanism 33 is for adjusting the irradiation range of the heating laser light LBh for the workpiece W; and the objective lens 34 is for adjusting the focus of the heating laser light LBh. As described above, the CO ₂ laser is used as the heating laser light LBh, and thus the laser oscillator 31 is an oscillator for CO ₂ laser.

Moreover, the mirror 35 is also included in the heating laser system 30 for reflection by reflection. The direction of the optical path of the heating laser light LBh is appropriately changed by heating the laser light LBh. Further, although the case where only one mirror 35 is included is illustrated in FIG. 6, the number of the mirrors 35 is not limited thereto, and the layout of the inside of the laser optical system 30 for heating or the device 100 is broken. For other reasons, it is also possible to provide more mirrors 35 and appropriately set the form of the optical path of the heating laser light LBh.

More specifically, in the laser oscillator 31, a shutter 31a for switching the non-exiting of the heating laser light LBh is provided. The switching operation of the shutter 31a is controlled based on the ON/OFF control signal sg6a which is one of the heating laser control signals sg6. Further, the adjustment of the amount of light of the heating laser light LBh in the attenuator 32 is controlled based on the output power control signal sg6b which is one of the heating laser control signals sg6.

Moreover, the beam adjustment mechanism 33 is included in order to adjust the irradiation range of the heating laser light LBh that is linearly emitted from the laser oscillator 31. The beam adjustment mechanism 33 can be realized, for example, by appropriately combining various lenses, and by adjusting the positions of the lenses, the workpiece W can be irradiated with the heating laser light LBh in an appropriate irradiation range. Further, in FIG. 6, the case where the heating laser light LBh is irradiated to the workpiece W by an irradiation range larger than the beam diameter when the laser oscillator 31 is emitted by the adjustment of the light beam adjusting mechanism 33 is exemplified. .

The position reading optical system 40 images a workpiece W that is adsorbed and fixed to the processing stage 12 by a CCD (Charge Coupled Device) camera or the like (not shown), and images the obtained captured image. The data is supplied to the control system 50 as the image information signal sg7. Control System The setting of the moving range of the XY stage 11, or the irradiation light of the scribing laser light LBs or the heating laser light LBh is performed based on the obtained image information signal sg7.

In the breaking device 100 having the above configuration, the workpiece W can be moved relative to the scribing by moving the XY stage 11 while the workpiece W is being adsorbed and fixed to the processing stage 12. Each of the laser optical system 20, the heating laser optical system 30, and the position reading optical system 40 is disposed opposite to the bottom. In this case, the workpiece W is fixed to the processing stage 12 such that the scribing surface W1 becomes the upper surface (non-mounting surface).

In the state in which the workpiece W is aligned with the scribing laser optical system 20, the workpiece W is irradiated with the scribing laser light LBs from the scribing laser system 20, and the XY loading is performed. The stage 11 is moved to realize relative scanning of the laser light LBs for scribing the workpiece W. The scribe line SL can be formed by relatively scanning the predetermined laser beam LBs along the predetermined breaking position of the scribe line W1.

In the same manner, the workpiece W is irradiated with the heating laser light LBh and the XY stage 11 is irradiated from the heating laser system 30 in a state in which the workpiece W is placed opposite to the heating laser optical system 30. Moving, the relative scanning of the heating laser light LBh for the workpiece W is achieved. By scanning the heating laser light LBh along the scribe line SL formed by the irradiation of the laser light LBs by the scribe line, the crack CR is made from the scribe line SL to the non-scribe surface W2 of the workpiece W. The predetermined breaking position progresses, whereby the workpiece W can be separated.

Further, in the breaking device 100, the workpiece W by the position reading optical system 40 can be imaged while the workpiece W is placed opposite to the position reading optical system 40, and based on the obtained The image data is captured, and an alignment operation for correcting the tilt (posture) in the horizontal plane of the workpiece W is performed. Specifically, the control system 50 specifies the tilt in the horizontal plane of the workpiece W based on the image content of the captured image data (for example, the arrangement position of the alignment mark or the arrangement position of the repeating pattern, etc.) (from the XY load) The tilt of the movement direction of the stage 11 is supplied to the processing stage 12 to provide a rotation control signal sg4 to rotate the processing stage 12 to cancel the tilt. As a main method of tilting in the horizontal plane of the specific workpiece W, a well-known method such as a pattern matching method can be applied.

In the case of the normal cutting process, the workpiece W is fixed to the processing stage 12 so that the scribing surface W1 becomes the upper surface (non-mounting surface), and the position reading optical system is used. After the imaging of 40 and the subsequent alignment processing, the formation of the scribe line SL by the laser optical system 20 for scribing is performed, and further, the laser light LBh for heating is irradiated by the heating laser optical system 30. The workpiece W.

<Ironizing the non-lined surface to irradiate the laser light for heating>

Hereinafter, the form of various breaking processes to which the above-described principle is applied will be described in order. FIG. 7 and FIG. 8 schematically show a mode in which the non-scribe surface W2 of the workpiece W is scanned by the heating laser light LBh. Fig. 7 is a cross-sectional view of the workpiece W perpendicular to the extending direction of the scribe line SL, and Fig. 8 is a cross-sectional view of the workpiece W along the scribe line SL.

In the case shown in FIGS. 7 and 8, unlike the case of FIG. 1, the pre-form The scribing surface W1 having the scribe line SL is placed on the processing stage 12, and the heating laser light LBh is irradiated to the predetermined breaking position L0 which is the non-scribe surface W2 of the non-mounting surface. When the heating laser light LBh is irradiated in this manner, the vicinity of the irradiation position of the heating laser light LBh of the non-scribe surface W2 becomes the compressive stress field SF1, and the vicinity of the compressive stress field SF1 is also the tensile stress field SF2. . In the case shown in FIG. 7, the scribe line SL is formed as a groove portion, but the formation form of the scribe line SL is not limited thereto (the same applies to FIGS. 7 and 14).

More specifically, when the heating laser light LBh is irradiated in the form shown in FIG. 7, the tensile stress field SF2 is formed not only on the non-scribe surface W2 but also inside the workpiece W. Therefore, the tensile stress TS acts on the front end portion of the scribe line SL located inside the workpiece W. As a result, the crack CR progresses from the scribe line SL to the predetermined breaking position L0 above it. Since the heating laser light LBh is scanned in the scanning direction indicated by the arrow AR1 in Fig. 8, the progress portion of the crack CR also moves. As a result, the division of the substrate is achieved in the same manner as in the case of FIG.

Further, in more detail, the spatial distribution of the stress field formed by the heating laser light LBh is the same as that of the case of Fig. 1 and the same as the case of Figs. 7 and 8. In the case of FIG. 1, the scribing surface W1 is set as the irradiated surface of the heating laser light LBh, and the crack CR is mainly progressed by the stress distribution in the scribing surface W1 which is a horizontal plane, and FIG. 7 In the case of Fig. 8, the stress distribution in the thickness direction (cross-sectional direction) of the workpiece W is mainly used to progress the crack CR, which is different in this respect.

Fig. 9 is a view showing that the laser light for heating is irradiated to the non-line surface W2 as described above. A schematic diagram of the LBh breaking device 200. In FIG. 9, the same components as those of the breaking device 100 shown in FIGS. 4 to 6 are denoted by the same reference numerals. Further, although not shown in FIG. 9, the breaking device 200 includes the control system 50 in the same manner as the breaking device 100.

The breaking device 200 has a configuration in which an inverting mechanism 60 is added to the breaking device 100. The reversing mechanism 60 moves forward and backward with respect to the workpiece W as indicated by an arrow AR3, and includes a chuck 61 that grips the workpiece W from the side, and a lifting portion 62 that holds the workpiece W. The chuck 61 of the state is raised and lowered in the vertical direction as indicated by an arrow AR4; and the reversing portion 63 is surrounded and held by the chuck 61 in a state in which the workpiece W is held. The vertical axis is reversed by 180° to invert the workpiece W. The reversing mechanism 60 operates in accordance with a control signal from the control system 50.

In the breaking device 200 including the reversing mechanism 60, the workpiece W is fixed to the processing stage 12 so that the scribing surface W1 becomes the upper surface (non-mounting surface), and Similarly, the breaking device 100 performs imaging by the position reading optical system 40 and subsequent alignment processing, and formation of the scribe lines SL in the scribing laser optical system 20. When the formation of the scribe line SL is completed, the processing stage 12 to which the workpiece W is fixed is moved below the reversing mechanism 60.

When the workpiece W is located immediately below the reversing mechanism 60, the suction fixing of the workpiece in the processing stage 12 is released, and the workpiece W is held by the chuck 61. The chuck 61 holding the workpiece W is lifted upward by the lifting portion 62. Then, when the processing stage 12 is retracted from directly below the reversing mechanism 60, the inverting portion 63 reverses the workpiece W. If this is the end When the rotation is reversed, the machining stage 12 is again placed below the reversing mechanism 60. When the chuck 61 is lowered by the lifting unit 62, the workpiece W is placed on the processing stage 12 while the non-scribe line surface W2 is on the upper surface, and is again adsorbed and fixed.

Thereafter, after the image capturing and alignment processing by the position reading optical system 40 is resumed, the cutting process in the heating laser optical system 30 is performed.

In addition, the workpiece W that is reversed by the reversing mechanism 60 may be attached to the processing stage 12 with the non-scribe line surface W2 as the upper surface, and may be attached in advance. The ring of the adhesive film is placed on the processing stage 12, and the processed object W which is processed and reversed is placed on the film and attached to the film, and the workpiece W is joined together with the film. fixed.

<Cooling of tensile stress field>

As a method of generating the progress of the crack CR in the tensile stress field SF2 more efficiently, there is a method of cooling the tensile stress field SF2.

FIG. 10 and FIG. 11 are schematic diagrams showing a state in which the tensile stress field SF2 is cooled in the configuration in which the heating laser light LBh is applied to the scribe line W1. Fig. 10 is a cross-sectional view of the workpiece W perpendicular to the extending direction of the scribe line SL, and Fig. 11 is a plan view of the workpiece W.

In FIGS. 10 and 11, when the scribing surface W1 is scanned in the scanning direction indicated by the arrow AR1 by the heating laser light LBh, the portion behind the scanning direction in the formed tensile stress field SF2 is The cooling gas CG is sprayed.

When cooling is performed in this form, the temperature difference between the portion to be cooled of the tensile stress field SF2 and the compressive stress field SF1 heated by the irradiation of the heating laser light LBh becomes higher, and the tensile stress field SF2 is Tensile stress becomes Stronger. Thereby, the accuracy of the progress of the crack CR is improved. As a result, the workpiece W can be separated with higher precision.

In addition, as the cooling gas CG, for example, a gas that does not react with the workpiece W such as an inert gas may be used as appropriate.

Fig. 12 is a view schematically showing an example of a configuration for realizing the injection of the cooling gas CG in the breaking device 100 shown in Figs. 4 to 6 . That is, in the case shown in Fig. 12, the nozzle 36 for injecting the cooling gas CG to the heating laser optical system 30 is attached, and the cooling gas CG supplied from the cooling gas supply source 37 through the supply pipe 38 can be supplied. The scanning (relative scanning) of the heating laser light LBh is simultaneously ejected from the nozzle 36 to the tensile stress field SF2.

However, the form of the cooling tensile stress field SF2 is not limited to the form of the ejection of the cooling gas CG as described above, and the liquid cooling may be performed as long as there is no problem with the reactivity with the workpiece or the corrosion of the breaking device. . That is, cooling using a fluid containing a gas and a liquid can also be performed. Further, it may be a form in which the solid refrigerant is cooled by approaching or contacting the tensile stress field SF2.

FIG. 13 is a view schematically showing an example of a configuration in which the cooling tensile stress field SF2 is provided in the breaking device 200 shown in FIG. 9. In the breaking device 200, a tensile stress field SF2 is formed from the inside of the workpiece W fixed to the processing stage 12 to the mounting surface side. Therefore, as shown in FIG. 13, the processing stage 12 is provided with a cooling mechanism 13 for cooling the workpiece W placed on the upper surface thereof from the side of the scribe line W1. By providing such a cooling mechanism 13, the tensile stress in the tensile stress field SF2 is further enhanced. Thereby, the accuracy of the progress of the crack CR is improved. As a result, it can be higher The workpiece W is divided in degrees.

As the cooling mechanism 13, for example, a Peltier element, a cooling plate, or the like can be used.

As described above, according to the present embodiment, by irradiating the laser beam for scribing, the laser beam for heating is irradiated along a scribe line formed in advance at a predetermined breaking position of the workpiece, and the workpiece is heated by heating. The tensile stress acts on the scribe line, and the progress of the crack from the scribe line to the non-scribe surface is sequentially generated along the extending direction of the scribe line, whereby the workpiece can be separated. Further, by cooling the tensile stress field, the progress of the crack can be generated more efficiently.

Further, the scribe line processing in which the scribe line is irradiated with the laser light can be performed after positioning the processing target with high precision. Therefore, in the same apparatus, the scribe line is formed with high precision at the predetermined breaking position, and then the tensile stress by the laser heating is generated, whereby the high-precision breaking processing can be efficiently performed.

<Modification>

Fig. 14 is a view showing another form of irradiating the non-line surface W2 with the heating laser light LBh. In the above-described embodiment, the non-line surface W2 is directed upward, and the heating laser light LBh is irradiated from above, and the non-line surface W2 is irradiated with the heating laser light LBh. As shown in FIG. 14, the heating laser light LBh is irradiated from the lower side toward the non-scribe line surface W2 in a state where the non-scribe line surface W2 is directed downward, and the tensile stress TS is applied to the scribe line SL. This can be achieved by, for example, forming the processing stage 12 by the material for transmitting the heating laser light LBh in the breaking device 100, and providing a heating thunder below the processing stage 12. Optical system 30.

10‧‧‧The Stage Department

11‧‧‧XY stage

12‧‧‧Processing stage

13‧‧‧Cooling mechanism

20‧‧‧ Laser optical system for marking

21‧‧‧Laser oscillator

21a‧‧ ‧Shutter

22‧‧‧Attenuator

23‧‧‧ Objective lens

24‧‧ ‧ mirror

30‧‧‧Lighting laser system for heating

31‧‧‧Laser oscillator

31a‧‧ ‧Shutter

32‧‧‧Attenuator

33‧‧‧beam adjustment mechanism

34‧‧‧ Objective lens

35‧‧‧Mirror

36‧‧‧Nozzles

37‧‧‧Cooling gas supply

38‧‧‧Supply tube

40‧‧‧Optical system

50‧‧‧Control system

60‧‧‧Reversal mechanism

61‧‧‧ chuck

62‧‧‧ Lifting Department

63‧‧‧Reversal Department

100‧‧‧ Breaking device

200‧‧‧ Breaking device

CG‧‧‧Cooling gas

CR‧‧‧ crack

L0‧‧‧Predetermined breaking position

LBh‧‧‧Lighting for heating

LBs‧‧‧Leading laser light

SF1‧‧‧Compressive stress field

SF2‧‧‧ tensile stress field

SL‧‧‧

TS‧‧‧ tensile stress

W‧‧‧Processed objects

W1‧‧‧ (worked object) line

W2‧‧‧ (processed material) non-dash surface

Fig. 1 is a view schematically showing a situation in the middle of the breaking process.

2 is an SEM image of a cross section of a sapphire substrate when a CO ₂ laser is used as the heating laser light LBh.

3(a) and 3(b) are diagrams showing the difference in the forward direction of the light in the cross-section when the split surface is relatively flat and the undulation is present on the flat surface.

FIG. 4 is a view schematically showing the configuration of the breaking device 100.

Fig. 5 is a view showing a detailed configuration of the laser optical system 20 for scribing.

Fig. 6 is a view showing a detailed configuration of the heating laser optical system 30.

FIG. 7 is a view schematically showing a state in which the non-scribe surface W2 of the workpiece W is scanned by the heating laser light LBh.

FIG. 8 is a view schematically showing a state in which the non-scribe surface W2 of the workpiece W is scanned by the heating laser light LBh.

FIG. 9 is a view showing a schematic configuration of the breaking device 200.

FIG. 10 is a schematic view showing a state in which the tensile stress field SF2 is cooled in the configuration in which the heating laser light LBh is applied to the scribe line W1.

FIG. 11 is a schematic view showing a state in which the tensile stress field SF2 is cooled in the configuration in which the heating laser light LBh is applied to the scribe line W1.

FIG. 12 is a view schematically showing an example of a configuration for realizing the injection of the cooling gas CG in the breaking device 100.

FIG. 13 is a view schematically showing an example of a configuration in which the cooling tensile stress field SF2 is provided in the breaking device 200.

Fig. 14 is a view showing another form of irradiating the non-line surface W2 with the heating laser light LBh.

12‧‧‧Processing stage

13‧‧‧Cooling mechanism

30‧‧‧Lighting laser system for heating

W‧‧‧Processed objects

Claims (11)

A method for dividing a workpiece, characterized in that it is a method for separating a workpiece, and comprising: a scribing processing step of causing the first laser light to be emitted from the first emission source, and The scribing surface of the workpiece is irradiated with the first laser light, and the scribing surface is formed with a scribe line; and an irradiation heating step is performed by ejecting the second laser light from the second emission source The second laser light is irradiated along the line on the opposite side of the line surface, and the workpiece is heated along the scribe line; and in the irradiation heating step, The second laser light is scanned relative to the scribe line while the scribe line is in contact with the cooling medium, and the second laser light is scanned by the second laser light. Irradiation of the non-line surface, the tensile stress field formed in the inside of the workpiece including the scribing surface and in the vicinity of the scribe line is moved and cooled, whereby the scribe line is located at the tensile stress From the above Sequentially generated along the scribe line to the crack to progress in the face of the non-chain line, thereby breaking the above-mentioned workpiece. The method for dividing a workpiece according to claim 1, wherein in the irradiation heating step, the second laser light is irradiated after the irradiation range of the second laser light emitted from the second emission source is adjusted by an adjustment mechanism Irradiation to the above non-lined surface. A method of breaking a workpiece according to claim 1 or 2, wherein said second laser light is a CO ₂ laser. The method for dividing a workpiece according to claim 3, wherein in the illuminating step, the second laser light is irradiated in a pulse oscillation mode to separate a single piece formed by the workpiece In the above, an undulation for reducing the total reflectance with a period corresponding to the pulse oscillation period is generated. The method for breaking a workpiece according to claim 1 or 2, wherein the first laser light system is a triple harmonic of the YAG laser. The method for breaking a workpiece according to claim 1 or 2, further comprising an alignment processing step of correcting a posture in a horizontal plane of the workpiece; and performing the above alignment processing In the step, the object to be processed is subjected to the scribing processing step and the irradiation heating step. The method for dividing a workpiece according to claim 1 or 2, wherein in the scribing processing step, the irradiated position is changed into a metamorphic region by melting and re-solidifying the irradiated position of the first laser light, Thereby the above scribe line is formed. The method for dividing a workpiece according to claim 1 or 2, wherein in the scribing step, the groove is formed at the irradiated position by ablation of the irradiated position of the first laser light, thereby forming a groove portion The above line. The breaking method of the workpiece according to claim 1 or 2, wherein in the scribing processing step, a plurality of scribe lines are formed at a specific pitch in the first direction and the second direction orthogonal to each other; In the irradiation heating step, after the irradiation of the scribe line extending from the non-scribe surface side along the first direction is performed, the scribe line extending along the second direction is performed. Irradiation heating. The method for dividing a workpiece according to claim 9, wherein in the irradiation heating step, the diameter of the irradiation beam of the second laser light is set to be equal to or less than a distance between the scribe lines. A method for breaking a substrate having an optical element pattern, characterized in that it is a method for dividing a substrate having an optical element pattern in which an optical element pattern is two-dimensionally formed on a surface, and includes: a scribing processing step, The first laser light is emitted from the first emission source, and the first laser light is irradiated onto the scribe line surface of the substrate having the optical element pattern, and a scribe line is formed on the scribe line surface; and an irradiation heating step is performed. The second laser light emitted from the second emission source, which is a CO ₂ laser, is emitted from the second emission source, and the second laser light is irradiated from the scribe line side along the scribe line to form the substrate along the optical element pattern. Heating the scribe line; and in the illuminating step, scanning the second laser light along the scribe line to cause the second ray on the substrate having the optical element pattern The tensile stress field formed around the irradiation heating region by the irradiation of the light is moved, thereby causing the crack from the scribe line to the non-scribe surface due to the scribe line being located in the tensile stress field The progress is sequentially generated along the above-mentioned scribe lines to divide the substrate having the optical element pattern; and the second laser light is emitted in a pulse oscillation mode to form an optical body by dividing the workpiece On the cross-section of the component monolith, an undulation for reducing the total reflectance of the period corresponding to the pulse oscillation period is generated.