TWI509743B - Processing method of optical device wafers - Google Patents

Description

Optical device wafer processing method Field of invention

The present invention relates to a method for processing an optical device wafer, which is formed by laminating an optical device layer on a surface of a substrate and forming a plurality of regions divided by a plurality of dicing streets formed in a lattice shape. An optical device wafer having an optical device is divided into optical devices along a scribe line.

Background of the invention

In the optical device manufacturing step, an optical device layer made of a potassium nitride-based compound semiconductor is laminated on a surface of a substantially circular plate-shaped sapphire substrate or a tantalum carbide substrate, and is divided into a plurality of dicing lines formed in a lattice shape. The region forms an optical device such as a light-emitting diode or a laser diode to form an optical device wafer. Then, by cutting the optical device wafer along the dicing street, the region where the optical device is formed is divided, and optical devices are manufactured.

The cutting of the dicing tracks along the wafer of the optical device is generally performed by a cutting device called a cutting machine. This cutting device includes a chuck table for holding a workpiece, a cutting mechanism for cutting and holding a workpiece on the chuck table, and a cutting feed mechanism for moving the chuck table and the cutting mechanism relative to each other. The cutting mechanism has a rotating mandrel, a cutting insert mounted on the mandrel, and a driving device for rotationally driving the rotating mandrel. The cutting insert is composed of a disc-shaped base and an annular cutter attached to the outer peripheral portion of the side surface of the base. The cutter is fixed by electroforming to a diamond abrasive grain having a particle diameter of about 3 μm and formed to a thickness of 20 μm. about.

As described above, since the Mohs hardness of the sapphire substrate or the tantalum carbide substrate constituting the optical device wafer is high, the cutting by the cutting insert is not necessarily easy. Therefore, since the cutting amount of the cutting insert cannot be increased and a plurality of cutting steps are performed to cut the optical device wafer, there is a problem that productivity is poor.

In order to solve the above problems, a method of dividing an optical device wafer along a dicing street has been proposed, which is formed by pulsing a laser beam of a wavelength that absorbs light to the wafer along a scribe line. The laser processing groove of the starting point is cut by the cutting force along the cutting path forming the laser processing groove which is the starting point of the breaking. (Refer to Patent Document 1.)

Advanced technical literature Patent literature

Patent Document 1 Japanese Patent Laid-Open Publication No. 10-305420

However, when a laser beam having an absorptive wavelength to the sapphire substrate is irradiated along a dicing street formed on the surface of the sapphire substrate constituting the optical device wafer to form a laser processing groove, the deterioration is generated during laser processing. The substance adheres to the side wall surface of the optical device such as the light-emitting diode, and the brightness of the optical device is lowered, and the quality of the optical device is lowered.

The present invention has been made in view of the above circumstances, and a main technical object thereof is to provide a method of processing an optical device wafer that can be divided into optical devices without degrading the quality of the optical device.

In order to solve the above-mentioned main technical problems, according to the present invention, there is provided a method for processing an optical device wafer, wherein the optical device wafer processing method is to laminate an optical device layer on a surface of the substrate, and form a plurality of dicing streets in a lattice shape. a plurality of divided optical regions forming an optical device wafer, and dividing the optical device into optical devices along the scribe line, characterized by having a laser processing groove forming step, a modifying substance removing step, and a wafer dividing step, The laser processing groove forming step is to irradiate the substrate of the optical device wafer with the absorbing light of the wavelength of the laser along the scribe line to form a laser processing groove as a breaking base point on the surface or the back surface of the substrate; In the material removal step, the cutting insert having the diamond abrasive grains as a main component is placed on the laser processing groove formed on the substrate, and the cutting blade is rotated while rotating along the wall surface and the side of the laser processing groove. , which can be removed from the metamorphic substance formed when forming the laser processing groove, and at the same time, the wall surface of the laser processing groove is processed into a rough surface; The step of imparting an external force to the wafer-based optical devices to the optical device wafer has been removed along the groove machining deteriorated substances OFF, divided into optical devices such persons.

The laser processing groove forming step irradiates the laser beam from the back side of the substrate along the dicing street to form a laser processing groove on the back surface of the substrate.

In addition, an optical device layer separation step is preferably performed. The optical device layer separation step uses a cutting blade mainly composed of diamond abrasive grains, and an optical device layer along which an optical device wafer of a laser processing groove is formed on the back surface of the substrate Cutting the cutting path to separate the optical device layer along the cutting path.

In the method for processing an optical device wafer of the present invention, a metamorphic substance removing step is performed, wherein the cutting blade having a diamond abrasive particle as a main component is placed in the optical processing groove forming step to form an optical The laser processing groove of the substrate of the device rotates the cutting blade while moving along the wall surface of the laser processing groove, thereby removing the metamorphic substance generated when the laser processing groove is formed, and simultaneously removing the thunder Since the wall surface of the processing groove is processed into a rough surface, the optical device divided into the optical devices can remove the light from the side wall surface of the substrate, and the modified material which is reduced in brightness is processed into a rough surface, so that the light can be efficiently released. The brightness can be increased.

Simple illustration

1(a) and 1(b) are a perspective view and an enlarged partial cross-sectional view showing an optical device wafer processed by the optical device wafer processing method of the present invention.

2(a) and 2(b) are explanatory views of a protective member attaching step of the method for processing an optical device wafer of the present invention.

Fig. 3 is a perspective view showing the main part of a laser processing apparatus for performing a laser processing groove forming step of the optical device wafer processing method of the present invention.

4(a) to 4(c) are explanatory views of a laser processing groove forming step of the method for processing an optical device wafer of the present invention.

Fig. 5 is a perspective view showing a main part of a cutting device for performing a metamorphic substance removing step of the method for processing an optical device wafer of the present invention.

6(a) to 6(c) are explanatory views of a metamorphic substance removing step of the method for processing an optical device wafer of the present invention.

7(a) and 7(b) are explanatory views of a wafer supporting step of the method for processing an optical device wafer of the present invention.

Fig. 8 is an explanatory view showing an optical device layer separation step of the optical device wafer processing method of the present invention.

9(a) to 9(c) are explanatory views of the optical device layer separation step of the optical device wafer processing method of the present invention.

Fig. 10 is a perspective view of a tape expanding device for performing a wafer dividing step of the method for processing an optical device wafer of the present invention.

11(a) to 11(c) are explanatory views of a wafer dividing step of the method for processing an optical device wafer of the present invention.

Form for implementing the invention

Hereinafter, preferred embodiments of the method for processing an optical device wafer according to the present invention will be described in detail with reference to the accompanying drawings.

1(a) and 1(b) are perspective views showing a wafer of an optical device processed by the method for processing an optical device wafer according to the present invention, and a cross-sectional view showing an enlarged main portion. The optical device wafer 2 shown in the first (a) and the first (b) is laminated on the surface 20a of the sapphire substrate 20 having a thickness of 100 μm by a thickness of 5 μm, and is formed of a nitride semiconductor as a light-emitting layer of the optical device layer. (Ettrium layer) 21. Further, an optical device 23 such as a light-emitting diode or a laser diode is formed in a plurality of regions defined by a plurality of dicing streets 22 formed in a lattice shape in the light-emitting layer (the epitaxial layer) 21. Hereinafter, a description will be given of a processing method in which the optical device wafer 2 is divided into the optical devices 23 along the dicing street 22.

First, in order to protect the optical device 23 formed on the surface 20a of the sapphire substrate 20 constituting the optical device wafer 2, a protective member attaching step of attaching the protective member to the surface 2a of the optical device wafer 2 is performed. That is, as shown in FIG. 2, the protective tape 3 as a protective member is attached to the surface 2a of the optical device wafer 2. Further, in the embodiment shown in the drawing, the protective tape 3 is coated with an acrylic resin-based paste having a thickness of 5 μm on the surface of a sheet substrate made of polyvinyl chloride (PVC) having a thickness of 100 μm.

After the protective member attaching step is performed, the protective tape 3 is attached to the surface 2a of the optical device wafer 2, and a laser processing groove forming step is performed along the cutting path to illuminate the optical The substrate of the device wafer has a laser beam of an absorptive wavelength to form a laser processing trench as a break point. This laser processing groove forming step is carried out using the laser processing apparatus 4 shown in Fig. 3. The laser processing apparatus 4 shown in Fig. 3 includes a chuck table 41 for holding a workpiece, a laser beam irradiation unit 42 for irradiating a laser beam to the workpiece held by the chuck table 41, and a lens holder 41 for photographing and holding. The photographing mechanism 43 of the workpiece to be processed. The suction cup table 41 is configured to attract and hold the workpiece, and can be moved by a machining feed mechanism (not shown) to move in the machining feed direction indicated by an arrow X in FIG. 3, and is not shown in the drawing. The indexing feed mechanism moves in the indexing feed direction indicated by the arrow Y in Fig. 3.

The above-described laser beam irradiation mechanism 42 has a cylindrical casing 421 which is substantially horizontally arranged. A pulsed laser ray oscillating mechanism having a pulsed laser ray oscillator and a repetition frequency setting mechanism (not shown) is disposed in the casing 421. A concentrator 422 for concentrating the pulsed laser light oscillating from the pulsed laser ray oscillating mechanism is disposed at a front end of the casing 421. In addition, the laser beam illumination mechanism 42 has a spot position adjustment mechanism (not shown) for adjusting the position of the spot of the pulsed laser beam condensed by the concentrator 422.

The photographing mechanism provided at the end portion of the casing 421 constituting the laser beam irradiation unit 42 has an illumination mechanism for illuminating the workpiece, an optical system for capturing an area illuminated by the illumination unit, and an image captured by the optical system. The imaging element (CCD) or the like transmits the captured image signal to a control mechanism not shown.

The laser processing groove forming step described below is described with reference to FIGS. 3 and 4, wherein the laser processing groove forming step uses the laser processing apparatus 4 to illuminate the wafer 2 along the scribe line. The sapphire substrate 20 has a laser beam of an absorptive wavelength to form a laser processing trench as a break point.

First, the side of the protective tape 3 attached to the surface of the optical device wafer 2 is placed on the chuck table 41 of the laser processing apparatus 4 shown in Fig. 3 described above. Then, by moving the suction mechanism (not shown), the optical device wafer 2 is held on the chuck table 41 by the protective tape 3 (wafer holding step). Therefore, the optical device wafer held on the chuck table 41 is on the upper side of the back surface 20b of the sapphire substrate 20. In this manner, the chuck table 41 holding the optical device wafer 2 is sucked and placed at a position directly below the photographing mechanism 43 by a processing feed mechanism (not shown).

When the chuck table 41 is placed directly under the photographing mechanism 43, the photographing mechanism 43 and the control unit (not shown) perform a calibration operation for detecting the processing region of the optical device wafer 2 to be subjected to laser processing. That is, the photographing mechanism 43 and the control unit (not shown) perform the gathering of the dicing street 22 for forming the predetermined direction of the optical device wafer 2 and the laser beam illuminating mechanism 42 for irradiating the laser beam along the dicing street 23. The image matching of the alignment of the optical device 422 is performed, and the calibration of the position of the laser irradiation is completed (calibration step). Further, the calibration of the laser beam irradiation position is performed in the same manner for the scribe line 22 formed in the optical device wafer 2 in the direction perpendicular to the predetermined direction. At this time, the surface of the light-emitting layer (the epitaxial layer) 21 of the optical device wafer 2 on which the dicing streets 22 are formed is located on the lower side, and since the sapphire substrate 20 constituting the optical device wafer 2 is a transparent body, it can be obtained from the sapphire substrate. The cutting path 22 is photographed on the back side 20b side of 20.

When the dicing 22 formed on the surface of the light-emitting layer (the epitaxial layer) 21 of the optical device wafer 2 held on the chuck table 41 is detected as described above, after the calibration of the laser beam irradiation position is performed, as in the fourth ( a) As shown in the figure, the chuck table 41 is moved to the laser beam irradiation area where the concentrator 422 of the laser beam irradiation mechanism 42 is located, and one end of the predetermined scribe line 22 (the left end in the 4th (a)) It is placed directly below the concentrator 422 of the laser beam illumination mechanism 42. Then, the condensed spot P of the pulsed laser light irradiated from the concentrator 422 is aligned with the back surface 20b (upper surface) of the sapphire substrate 20 constituting the optical device wafer 2. Next, the pulsed laser beam having a wavelength absorbing to the sapphire substrate 20 is irradiated from the concentrator 422, and the chuck table 41 is fed in a predetermined processing direction in the direction indicated by an arrow X1 in the fourth (a) drawing. Speed moves. Then, as shown in Fig. 4(b), when the irradiation position of the concentrator 422 of the laser beam irradiation unit 42 reaches the other end of the scribe line 22 (the right end in the 4th (b) diagram), the stop is stopped. The irradiation of the pulsed laser light, at the same time, stops the movement of the chuck table 41. As a result, as shown in Figs. 4(b) and 4(c), a continuous laser processing groove 201 is formed along the dicing street 22 (laser processing groove forming step). Further, as shown in Fig. 4(c), the deteriorated substance 202 generated when the laser processing groove is formed is adhered to the wall surface of the laser processing groove 201.

The processing conditions of the above-described laser processing groove forming step are set as follows.

Light source: semiconductor excited solid laser (Nd: YAG)

Wavelength: 355nm

Pulse energy: 35μJ

Pulse width: 180ns

Repeat frequency: 100kHz

Converging spot diameter: Φ10μm

Processing feed rate: 60mm / sec

Ditch depth: 15μm

When performing the above-described laser processing groove forming step along all of the dicing streets 22 extending in the predetermined direction of the optical device wafer 2 as described above, the chuck table 41 is rotated by 90 degrees, formed along with respect to the above-mentioned predetermined Each of the dicing streets 22 in the direction in which the directions intersect perpendicularly performs the above-described laser processing groove forming step.

After performing the laser processing groove forming step, performing a metamorphic substance removing step of placing a cutting blade containing diamond abrasive grains as a main component in a laser processing groove formed on the substrate, and rotating the cutting blade side While moving along the wall surface of the laser processing groove, the side moves relative to each other, thereby removing the metamorphic substance generated when the laser processing groove is formed, and processing the wall surface of the laser processing groove into a rough surface. This deterioration substance removal step is carried out using the cutting device 5 shown in Fig. 5 in the embodiment shown in the drawing. The cutting device 5 shown in Fig. 5 includes a chuck table 51 for holding a workpiece, a cutting mechanism 52 for cutting and holding a workpiece on the chuck table 51, and a photographing mechanism 53 for photographing a workpiece held by the chuck table 51. . The suction cup table 51 is configured to attract and hold the workpiece, and can be moved by the cutting feed mechanism (not shown) in the cutting feed direction indicated by the arrow X in FIG. 5, and is not shown in the figure. The feed mechanism moves it in the indexing feed direction indicated by the arrow Y.

The cutting mechanism 52 has a spindle housing 521 that is substantially horizontal, a rotary spindle 522 that is rotatably supported by the spindle housing 521, and a cutting insert 523 that is attached to the front end of the rotary spindle 522. The mandrel 522 can be disposed in a spindle motor 521, which is not shown in the figure, and is rotated in the direction indicated by the arrow 523a. Further, in the embodiment shown in the drawing, the cutting insert 523 is composed of an electroformed insert in which diamond abrasive grains having a particle diameter of 3 μm are gathered by nickel plating, and the thickness is formed to be 20 μm. The imaging unit 53 has an illumination mechanism for illuminating a workpiece, an optical system for capturing an area illuminated by the illumination unit, an imaging element (CCD) for capturing an image captured by the optical system, and the like, and the captured image signal Transfer to a control mechanism not shown in the figure.

To use the above-described cutting device 5, a metamorphic substance removing step is performed, and as shown in Fig. 5, the side of the protective tape 3 attached to the surface of the optical device wafer 2 on which the laser processing groove forming step has been performed is placed on the chuck table. 51 on. Then, by moving the suction mechanism (not shown), the optical device wafer 2 is held on the chuck table 51 by the protective tape 3 (wafer holding step). Therefore, the optical device wafer 2 held by the chuck table 51 is on the upper side of the back surface 20b of the sapphire substrate 20. In this manner, the chuck table 51 holding the optical device wafer 2 is sucked so that the cutting feed mechanism (not shown) is placed directly under the photographing mechanism 53.

When the chuck table 51 is placed directly under the photographing mechanism 53, the photographing mechanism 53 and a control unit (not shown) perform a calibration operation for detecting the area of the wafer 2 to be processed. That is, the photographing mechanism 53 and the control unit (not shown) perform the alignment of the laser processing groove 201 and the cutting insert 523 which are formed in the predetermined direction on the back surface 20b of the sapphire substrate 20 constituting the optical device wafer 2. Calibration (calibration step). Further, the processing of the processing region is performed in the same manner in the laser processing groove 201 in which the back surface 20b of the sapphire substrate 20 constituting the optical device wafer 2 is formed in a direction perpendicularly intersecting the predetermined direction.

When the calibration of the processing area of the optical device wafer 2 held on the chuck table 51 is detected as described above, the chuck table 51 holding the optical device wafer 2 is sucked and moved to the processing area below the cutting blade 523. Start position. Then, as shown in Fig. 6(a), one end of the laser processing groove 201 to be processed (positioned at the left end in Fig. 6(a)) positioned as the optical device wafer 2 is located right below the cutting blade 523. Move the side of the predetermined amount (machining feed start position positioning step). When this is done, the optical device wafer 2 is placed at the processing start position of the processing region, and the cutting blade 523 is rotated in the direction indicated by the arrow 523a while being separated by a two-point chain line in the sixth (a) drawing. The standby position shown is cut into the feed to the lower side, and is placed at the predetermined cut-in feed position as indicated by the solid line in Fig. 6(a). This cut-in feed position is set at a position lower than the outer periphery of the cutting insert 523 from the back surface 20b (upper surface) of the sapphire substrate 20 constituting the optical device wafer 2 by 20 μm.

Next, as shown in Fig. 6(a), while the cutting insert 523 is rotated in the direction indicated by the arrow 523a, it is rotated at a predetermined rotational speed (for example, 20,000 rpm), and the chuck table 51, that is, the optical device wafer 2 is rotated. The feed is processed at a predetermined machining feed speed in the direction indicated by the arrow X1 in the 6th (a) (deterioration substance removal step). In this deteriorated substance removing step, the cutting insert 523 relatively moves while following the laser processing groove 201. As a result, since the thickness (20 μm) of the cutting insert 523 is set to be thicker than that of the laser processing groove 201 (formed by pulsed laser light having a spot diameter of Φ 10 μm), as shown in the above-mentioned FIG. 6(c), The deteriorated substance 202 adhering to the wall surface of the laser processing groove 201 can be removed, and as shown in Fig. 6(c), the processing groove 203 whose wall surface is processed into a rough surface is formed. In the step of removing the deteriorated substance, since the cutting insert 523 is processed while adhering to the deteriorated substance 202 adhering to the wall surface of the laser processing groove 201, the deteriorated substance 202 can be easily removed, and the laser processing groove 201 can be easily removed. The wall surface forms a rough surface. Further, when the chuck table 51, that is, the other end of the optical device wafer 2 (the right end in FIG. 6(b)) reaches a position shifted to the left from the directly below the cutting blade 523 by a predetermined amount, the movement of the chuck table 51 is stopped. . Then, the cutting insert 523 is raised and placed at the retracted position indicated by the 2-point chain line.

The processing conditions of the above-described deteriorated substance removal step are set as follows.

Cutting insert: electroforming insert of diamond abrasive grain with a thickness of 20μm

Cutting depth: 20μm

Processing feed rate: 60mm / sec

When performing the above-described deteriorated substance removing step along all the dicing streets 22 extending in the predetermined direction of the optical device wafer 2 as described above, the chuck table 51 is rotated by 90 degrees, and is formed to intersect perpendicularly with respect to the predetermined direction. In the laser processing grooves 201 in the direction, the above-described deteriorated substance removing step is performed.

After performing the metamorphic substance removing step as described above, a wafer supporting step of attaching the back surface 20b of the sapphire substrate 20 constituting the optical device wafer 2 to the surface of the dicing tape provided on the annular frame is performed. Further, the protective member attached to the surface of the optical device wafer 2 is peeled off. That is, as shown in FIGS. 7(a) and 7(b), the sapphire substrate constituting the optical device wafer 2 is attached to the surface of the dicing tape 7 which is provided to cover the inner opening portion of the annular frame 6 at the outer peripheral portion. 20 on the back 20b. Then, the protective tape 3 attached to the surface 2a of the optical device wafer 2 is peeled off.

Next, an optical device layer separation step of laminating the surface 20a formed on the sapphire substrate 20 constituting the optical device wafer 2 as a light-emitting layer (epitaxial layer) 21 of the optical device layer is performed along the cutting step. Road 22 is separated. This optical device layer separation step can be carried out using the cutting device 5 shown in Fig. 5 described above.

To use the above-described cutting device 5, an optical device layer separating step is performed, and as shown in Fig. 8, the side of the cutting tape 7 to which the back surface 20b of the sapphire substrate 20 constituting the optical device wafer 2 is attached is placed on the chuck table 51. In the above, the suction mechanism (not shown) is actuated to hold and hold the optical device wafer 2 on the chuck table 51 (wafer holding step). Therefore, the optical device wafer 2 held on the chuck table 51 has the surface 2a as the upper side. Further, in Fig. 8, the annular frame 6 on which the dicing tape 7 is attached is omitted, and the annular frame 6 is fixed by a clip device disposed on the chuck table 51. In this manner, the chuck table 51 holding the optical device wafer 2 is sucked and placed directly under the photographing mechanism 53 by a cutting feed mechanism (not shown).

When the chuck table 51 is placed directly under the photographing mechanism 53, the photographing mechanism 53 and a control unit (not shown) perform a calibration operation for detecting the area of the wafer 2 to be processed. That is, the photographing mechanism 53 and the control unit (not shown) perform the calibration (calibration step) for performing the alignment of the dicing street 22 formed in the predetermined direction on the surface 2a of the optical device wafer 2 and the cutting insert 523. Further, the calibration of the processing region is performed in the same manner with respect to the dicing streets 22 which form the surface 2a of the optical device wafer 2 and are formed to intersect perpendicularly with respect to the predetermined direction.

When the calibration of the processing area of the optical device wafer 2 held on the chuck table 51 is performed as described above, the chuck table 51 sucking and holding the optical device wafer 2 is moved to the processing area below the cutting blade 523. Processing start position. Then, as shown in Fig. 9(a), one end of the dicing street 22 to be processed which is positioned as the optical device wafer 2 (left end in Fig. 9(a)) is located right below the cutting blade 523 and is shifted right. The side of the quantity (processing feed start position positioning step). In this manner, after the optical device wafer 2 is placed at the processing start position of the processing region, the cutting blade 523 is rotated in the direction indicated by the arrow 523a, and a 2-point chain line is formed from the 9th (a) drawing. The standby position shown is cut into the feed to the lower side and, as indicated by the solid line in Fig. 9(a), placed in the predetermined cut-in feed position. This cut-in feed position is set at a position lower than the outer periphery of the cutting insert 523 from the surface 2a (upper surface) of the optical device wafer 2 by 8 μm.

Next, as shown in Fig. 9(a), while the cutting insert 523 is rotated in the direction indicated by the arrow 523a, it is rotated at a predetermined rotational speed (for example, 20,000 rpm) to cause the chuck table 51, that is, the optical device crystal. The circle 2 is fed at a predetermined machining feed speed in the direction indicated by the arrow X1 in the figure 9 (a) (optical device layer separating step). As a result, as shown in FIGS. 9(b) and 9(c), the cutting groove 204 is formed along the dicing street 22 on the surface 2a of the optical device wafer 2 as the light-emitting layer (the epitaxial layer) of the optical device layer. 21 may be separated along the scribe line 22, and a cutting mark 205 is formed along the scribe line 22 on the surface of the sapphire substrate 20. In the optical device layer separation step, since the light-emitting layer (the epitaxial layer) 21 which is an optical device layer formed on the surface 20a of the sapphire substrate 20 is formed by lamination, the cutting blade 523 can be easily cut. Further, when the chuck table 51, that is, the other end of the optical device wafer 2 (the right end in the ninth (b)th view) reaches the position shifted to the left of the cutting blade 523 by a predetermined amount to the left, the movement of the chuck table 51 is stopped. . Then, the cutting insert 523 is raised and placed at the retracted position indicated by the 2-point chain line.

The processing conditions of the above-described optical device layer separation step are set as follows.

Cutting insert: electroforming insert of diamond abrasive grain with a thickness of 20μm

Cutting depth: 8μm

Processing feed rate: 50mm / sec

When performing the above-described optical device layer separation step along all of the dicing streets 22 extending in the predetermined direction of the optical device wafer 2 as described above, the chuck table 51 is rotated by 90 degrees, and formed along the vertical direction with respect to the predetermined direction. The optical device layer separation step is performed on each of the dicing streets 22 in the intersecting direction.

Next, a wafer dividing step is performed, which applies an external force to the optical device wafer 2 to break the optical device wafer 2 along the processing groove 203 from which the deteriorated substance has been removed, and is divided into opticals. Device 23. The wafer dividing step is performed using the tape expanding device 8 shown in Fig. 10. The tape expanding device 8 shown in Fig. 10 includes a frame holding mechanism 81 that holds the annular frame 6, and a tape expanding mechanism for expanding the dicing tape 7 attached to the annular frame 6 held by the frame holding mechanism 81. 82 and pick up the collet 83. The frame holding mechanism 81 is composed of an annular frame holding member 811 and a plurality of clips 812 that are disposed on the outer circumference of the frame holding member 811 as a fixing mechanism. The mounting surface 811a of the annular frame 6 is formed on the upper surface of the frame holding member 811, and the annular frame 6 can be placed on the mounting surface 811a. Then, the annular frame 6 placed on the placing surface 811a can be fixed to the frame holding member 811 by the clip 812. The frame holding mechanism 81 thus configured is supported by the tape expanding mechanism 82 so as to be able to advance and retreat in the up and down direction.

The tape expansion mechanism 82 includes an expansion roller 821 disposed inside the annular frame holding member 811. The expansion roller 821 has an inner diameter and an outer diameter which are smaller than the inner diameter of the annular frame 6 and larger than the optical device wafer 2 attached to the dicing tape 7 mounted on the annular frame 6. The outer diameter of the person. Further, the expansion roller 821 has a support flange 822 at the lower end. The tape expansion mechanism 82 of the embodiment shown in the drawing includes a support mechanism 823 that allows the annular frame holding member 811 to advance and retreat in the vertical direction. The support mechanism 823 is composed of a plurality of cylinders 823a disposed on the support flange 822, and a piston rod 823b is coupled to the lower surface of the annular frame holding member 811. In this manner, the support mechanism 823 composed of the plurality of cylinders 823a causes the annular frame holding member 811 to have a reference position at a height approximately the same as the upper end of the expansion roller 821 as shown in Fig. 11(a). As shown in Fig. 11(b), the expansion position is lower than the upper end of the expansion roller 821 by a predetermined amount in the vertical direction.

The wafer dividing step performed using the tape expanding device 8 configured as above will be described with reference to FIG. In other words, as shown in Fig. 11(a), the annular frame 6 on which the dicing tape 7 to which the optical device wafer 2 is attached is placed on the mounting surface of the frame holding member 811 constituting the frame holding mechanism 81. On the 811a, the frame holding member 811 is fixed to the frame holding member 811 (frame holding step). At this time, the frame holding member 811 is placed at the reference position shown in Fig. 11(a). Next, the plurality of cylinders 823a as the supporting mechanism 823 constituting the tape expanding mechanism 82 are actuated to lower the annular frame holding member 811 to the expanded position shown in Fig. 11(b). Therefore, since the annular frame 6 fixed to the mounting surface 811a of the frame holding member 811 is also lowered, as shown in Fig. 11(b), the dicing tape 7 attached to the annular frame 6 contacts the expansion roller 821. The upper end edge is expanded (tape expansion step). As a result, the stretching force acts radially on the optical device wafer 2 attached to the dicing tape 7. Thus, when the tensile force acts radially on the optical device wafer 2, the processing groove 203 is formed along the dicing street 22 on the back surface 20b of the sapphire substrate 20 constituting the optical device wafer 2, and on the sapphire substrate 20 The surface 20a is formed with the cutting marks 204 along the dicing streets, so that the machining grooves and the cutting marks 204 are formed as the starting point of the breaking, the optical device wafer 2 is broken along the dicing street 22, and the optical device wafer 2 can be divided into pieces. Optical device 23 (wafer dividing step). Thus, a gap S is formed between the optical devices 23 divided into pieces.

Next, as shown in Fig. 11(c), the pickup collet 83 is actuated, the optical device 23 is sucked, and it is peeled off from the dicing tape 7 to be picked up (pickup step). Further, in the picking up step, as described above, since the gap S is formed between the optical devices 23 attached to the dicing tape 7, it can be easily picked up without coming into contact with the adjacent optical device 23. The optical device 23 which is divided in this manner performs the above-described deterioration substance removal step by the side wall surface of the sapphire substrate 20, removes the deteriorated substance which absorbs the light and causes the brightness to be lowered, and is processed into a rough surface, so that the light can be efficiently released, and the brightness can be improve.

Further, in the above embodiment, an example in which the optical device layer separating step is performed before the wafer dividing step is performed, or the optical device layer separating step may not be performed, and the wafer disconnection is performed after the modified substance removing step is performed. step.

2. . . Optical device wafer

2a. . . Optical device wafer surface

3. . . Protective tape

4. . . Laser processing device

5. . . Cutting device

6. . . Ring frame

7. . . Cutting tape

8. . . Tape expansion device

20. . . Sapphire substrate

20a. . . Surface of sapphire substrate

20b. . . Back of sapphire substrate

twenty one. . . Luminous layer

twenty two. . . cutting line

twenty three. . . Optical device

41. . . Laser table of the laser processing device

42. . . Laser light irradiation mechanism

43. . . Laser processing device

51. . . Sucker table for cutting device

52. . . Cutting mechanism

53. . . Cutting mechanism

81. . . Frame retention mechanism

82. . . Tape expansion mechanism

83. . . Pick up collet

201. . . Laser processing trench

202. . . Metamorphic substance

203. . . Processing trench

204. . . Cutting groove

205. . . Cutting marks

421. . . case

422. . . Concentrator

521. . . Mandrel shell

522. . . Rotating mandrel

523. . . Cutting insert

523a, X, X1, Y. . . Arrow

811. . . Annular frame retaining member

811a. . . Mounting surface

812. . . folder

821. . . Expansion roller

822. . . Support flange

823. . . Support mechanism

823a. . . cylinder

823b. . . Piston rod

P. . . Spotlight

S. . . gap

1(a) and 1(b) are a perspective view and an enlarged partial cross-sectional view showing an optical device wafer processed by the optical device wafer processing method of the present invention.

2(a) and 2(b) are explanatory views of a protective member attaching step of the method for processing an optical device wafer of the present invention.

Fig. 3 is a perspective view showing the main part of a laser processing apparatus for performing a laser processing groove forming step of the optical device wafer processing method of the present invention.

4(a) to 4(c) are explanatory views of a laser processing groove forming step of the method for processing an optical device wafer of the present invention.

Fig. 5 is a perspective view showing a main part of a cutting device for performing a metamorphic substance removing step of the method for processing an optical device wafer of the present invention.

6(a) to 6(c) are explanatory views of a metamorphic substance removing step of the method for processing an optical device wafer of the present invention.

7(a) and 7(b) are explanatory views of a wafer supporting step of the method for processing an optical device wafer of the present invention.

Fig. 8 is an explanatory view showing an optical device layer separation step of the optical device wafer processing method of the present invention.

9(a) to 9(c) are explanatory views of the optical device layer separation step of the optical device wafer processing method of the present invention.

Fig. 10 is a perspective view of a tape expanding device for performing a wafer dividing step of the method for processing an optical device wafer of the present invention.

11(a) to 11(c) are explanatory views of a wafer dividing step of the method for processing an optical device wafer of the present invention.

2. . . Optical device wafer

3. . . Protective tape

20. . . Sapphire substrate

20b. . . Back of sapphire substrate

twenty one. . . Luminous layer

twenty two. . . cutting line

51. . . Sucker table for cutting device

201. . . Laser processing trench

203. . . Processing trench

523. . . Cutting insert

523a, X1. . . Arrow

Claims (3)

An optical device wafer processing method is an optical device wafer in which an optical device layer is laminated on a surface of a substrate and an optical device is formed in a plurality of regions divided by a plurality of dicing streets formed in a lattice shape, along a dicing street Dividing into optical devices, comprising: a laser processing groove forming step of illuminating a substrate of the optical device wafer with a absorbing wavelength of laser light along a scribe line to surface or back of the substrate Forming a laser processing groove as a breaking base point; the removing material removing step is to place a cutting blade containing diamond abrasive grains as a main component in a laser processing groove formed on the substrate, and rotating the cutting blade while rotating The wall surface and the side of the laser processing groove are relatively moved, thereby removing the metamorphic substance generated when the laser processing groove is formed, and processing the wall surface of the laser processing groove into a rough surface; and the wafer dividing step, An external force is applied to the optical device wafer to break the optical device wafer along the processing groove from which the deteriorated material has been removed, and to divide into optical devices. The method of processing an optical device wafer according to claim 1, wherein the laser processing groove forming step irradiates the laser beam from the back side of the substrate along the dicing street to form a laser processing groove on the back surface of the substrate. The method for processing an optical device wafer according to claim 2, wherein the optical device wafer processing method has an optical device layer separating step, wherein the optical device layer separating step uses a cutting blade mainly composed of diamond abrasive particles. The optical device layer of the optical device wafer on which the laser processing trench is formed on the back side of the substrate is cut along the scribe line to separate the optical device layer along the scribe line.