TW201301377A - Processing method of optical device wafer - Google Patents

Abstract

The present invention provides a processing method of optical device wafer, capable of removing the area coated on the metal film of the back of a substrate corresponding to predefined partitioning lines without damaging the optical device layer. In the processing method of optical device wafer according to the present invention, the optical device wafer is that an optical device layer is laminated over the surface of a substrate, and an optical device is formed by a plurality of areas partitioned by a plurality of first predefined partitioning lines extended toward a predefined direction and a plurality of second predefined partitioning lines formed along a direction intersected with the first predefined partitioning lines, and a metal film is covered on the back of the substrate. The processing device includes: a first metal film removing step for irradiating laser beam from the side of metal film coated on the back of the substrate to the area corresponding to the first predefined partitioning lines, and removing the metal film along the first predefined partitioning lines so as to form a first laser processing groove; and a second metal film removing step for irradiating laser beam from the side of metal film coated on the back of the substrate to the area corresponding to the second predefined partitioning lines, and removing the metal film along the second predefined partitioning lines so as to form a second laser processing groove; wherein the second metal film removing step excludes the area intersected with the first laser processing groove formed by the first metal film removing step to irradiate laser beam.

Description

Optical component wafer processing method Technical area

The present invention relates to a method of processing an optical element wafer in which an optical element layer is laminated on a surface of a substrate, and is formed by a plurality of first dividing lines extending in a predetermined direction. The plurality of regions in which the plurality of second division planned lines intersect in the direction in which the first division planned line intersects form an optical element, and the back surface of the substrate is covered with a metal film.

Background technique

In the optical element manufacturing step, the surface of the substrate such as a sapphire substrate or a tantalum carbide substrate having a substantially disk shape is covered with an optical element layer made of a gallium nitride-based compound semiconductor, and is formed by a plurality of first division lines extending in a predetermined direction. The optical element wafer is formed in a plurality of regions defined by a plurality of second predetermined dividing lines formed in a direction intersecting the first dividing line to form an optical element such as a light emitting diode or a laser diode. Next, the optical element wafer is cut along the first dividing line and the second dividing line, thereby dividing the region in which the optical element is formed, and manufacturing one optical element.

A method of dividing the optical element wafer along the first dividing line and the second dividing line is proposed as a method of forming a substrate of the optical element wafer along the first dividing line and the second The predetermined line is irradiated with pulsed laser light having an absorptive wavelength to perform ablation processing, thereby forming a laser processing groove as a fracture starting point, and applying an external force along the first dividing line and the second dividing line to perform cutting. . (refer to eg patent Literature 1)

Further, there is another proposal for dividing the optical element wafer along the first division planned line and the second division planned line, that is, irradiating the substrate constituting the optical element wafer with pulsed laser light having an absorption wavelength, and concentrating The light spot is aligned with the inside and is irradiated along the first dividing line and the second dividing line, and a modified layer as a starting point of the fracture is continuously formed along the first dividing line and the second dividing line in the substrate, and is formed along the line. The first dividing line and the second dividing line which are the modified layers of the starting point of the fracture are applied with an external force to divide the wafer. (Refer to, for example, Patent Document 2)

In recent years, in order to enhance the luminance of an optical element, an optical element wafer in which a metal such as aluminum or gold having a thickness of about 1 μm is coated on the back surface of a substrate constituting the optical element wafer has been put into practical use. In this manner, in order to divide the optical element wafer on which the metal film is coated on the back surface of the substrate along the first dividing line and the second dividing line, first, the metal film side is irradiated with the laser light from the back surface of the substrate to correspond to the first dividing line. And a region of the second division planned line, and the metal film is removed in accordance with the first division planned line and the second division planned line.

Summary of invention

However, when the laser light is irradiated onto the metal film side coated on the back surface of the substrate to the region corresponding to the first division planned line, the metal film is removed corresponding to the first division planned line, and then the laser light is irradiated to correspond to the second. When the region of the predetermined line is divided, since the metal film is removed at the intersection corresponding to the first dividing line, the light beam formed by the laser light penetrating the substrate to the surface of the substrate The layer of the layer causes damage to the layer of the optical element, and the quality of the optical element is degraded.

The present invention has been made in view of the above circumstances, and a main technical object thereof is to provide an optical element wafer processing method capable of coating a metal coated on a back surface of a substrate without damaging the optical element layer. The area corresponding to the dividing line on the film is removed.

In order to solve the above-mentioned main technical problems, according to the present invention, there is provided a method of processing an optical element wafer, wherein the optical element layer on the surface of the substrate of the optical element is laminated, and the plurality of first divisions are extended by a predetermined direction. The predetermined line and the plurality of second dividing lines formed in a direction intersecting the first dividing line intersect to form a plurality of regions, and the back surface of the substrate is covered with a metal film; and the processing method is characterized in that the processing method is characterized in that The first metal film removing step includes irradiating the laser light to a region corresponding to the first dividing planned line from the side of the metal film coated on the back surface of the substrate, and removing the metal film along the first dividing line. The first laser processing groove is formed, and the second metal film removing step is performed by irradiating the laser light to the region corresponding to the second division planned line from the side of the metal film coated on the back surface of the substrate. The second division planned line removes the metal film to form the second laser processing groove; and the second metal film removal step excludes the first laser processing groove formed in the first metal film removal step Laser beam irradiated area.

Moreover, according to the present invention, there is provided an optical element wafer processing method in which an optical element layer is laminated on a surface of a substrate, and is formed by a plurality of first division lines and a predetermined line extending in a predetermined direction. With the first point a plurality of regions defined by the plurality of second predetermined lines intersecting the predetermined line intersecting to form an optical element, and the back surface of the substrate is covered with a metal film, and the processing method is characterized by including a first metal film removing step. The laser light is irradiated onto the metal film side covered on the back surface of the substrate, irradiated to a region corresponding to the first dividing line, and the metal film is removed along the first dividing line to form the first laser processing groove. And the second metal film removing step of irradiating the laser light to the region corresponding to the second planned dividing line from the side of the metal film coated on the back surface of the substrate, and removing the metal film along the second dividing line. Thereby, the second laser processing groove is formed; and the first metal film removing step excludes the region intersecting the region corresponding to the second division planned line to irradiate the laser light.

After performing the second metal film removing step, the reforming layer forming step is performed to penetrate the substrate along the first laser processing groove and the second laser processing groove from the back surface side of the substrate. The laser light of a dominant wavelength forms a modified layer along the first laser processing groove and the second laser processing groove inside the substrate.

According to the invention, since the second metal film removing step excludes the region intersecting with the first laser processing groove formed in the first metal film removing step, the laser light is irradiated, so that the laser light is not irradiated to the first laser processing. Since the groove is removed from the intersection region, the laser light is not irradiated to the optical element layer formed on the surface of the substrate, and damage to the optical element layer can be prevented.

Further, according to the present invention, since the first metal film removing step excludes the region intersecting the region corresponding to the second dividing planned line, the laser beam is irradiated, so that the laser light is irradiated. Then, in the second metal film removing step, when the laser light is irradiated to the region corresponding to the second division planned line, a metal film remains in the intersection region with the first laser processing groove formed in the first metal film removing step. Therefore, the laser light does not illuminate the layer of the optical element formed on the surface of the substrate, and damage to the layer of the optical element can be prevented.

Simple illustration

Figs. 1(a) and 1(b) are a perspective view of a light element wafer processed by the method for processing an optical element wafer of the present invention, and a cross-sectional view showing an enlarged portion.

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

Fig. 3 is a perspective view showing the essential part of the laser processing apparatus for the first metal film removing step and the second metal film removing step in the method for processing the optical element wafer of the present invention.

4(a) and 4(b) are explanatory views showing a first metal film removing step in the first embodiment in the method of processing an optical element wafer of the present invention.

The fifth (a) to (e) drawings are explanatory views showing the second metal film removing step in the first embodiment in the method of processing the optical element wafer of the present invention.

6(a) and 6(b) are explanatory views showing a first metal film removing step in the second embodiment in the method of processing an optical element wafer according to the present invention.

7(a) and 7(b) are explanatory views showing a second metal film removing step in the second embodiment in the method of processing an optical element wafer according to the present invention.

Fig. 8 is a perspective view of an important portion of a laser processing apparatus for performing a reforming layer forming step of the method for processing an optical element wafer of the present invention.

9(a) and (b) are diagrams showing the processing method of the optical element wafer of the present invention. An explanatory diagram of the reforming layer forming step.

The best form for implementing the invention

Hereinafter, preferred embodiments of the wafer processing method of the present invention will be described in detail with reference to additional drawings.

Fig. 1(a) and (b) are cross-sectional views showing a perspective view of an optical element wafer as a wafer and an important portion of the expansion. The optical element wafer 2 shown in FIGS. 1(a) and (b) is, for example, laminated on the surface 20a of the sapphire substrate 20 having a thickness of 100 μm, and laminated with an n-type nitride semiconductor layer with a thickness of, for example, 10 μm. An optical element layer (epitaxial layer) 21 composed of 211 and p-type nitride semiconductor layer 212. Further, the optical element layer (the epitaxial layer) 21 is partitioned by a plurality of first division planned lines 221 extending in a predetermined direction and a second division planned line 222 formed in a direction intersecting the first division planned line 221 In the region of the complex number, an optical element 23 such as a light-emitting diode or a laser diode is formed. Further, the back surface 20b of the sapphire substrate 20 is coated with a metal film 24 of a metal such as aluminum or gold by metal deposition. The thickness of the metal film 24 was set to 1 μm in the embodiment shown in the drawing. On the other hand, the sapphire substrate 20 constituting the optical element wafer 2 is formed with a notch 201 representing a crystal orientation. A method of processing the optical element wafer 2 along the first dividing line 221 and the second dividing line 222 will be described below.

First, in order to protect the optical element 23 formed on the surface 20a of the sapphire substrate 20 constituting the optical element wafer 2, a protective member adhering step of adhering the protective member to the surface 2a of the pair of optical element wafers 2 is performed. That is, as shown in Fig. 2, a protective tape T as a protective material is attached to the surface 2a of the optical element wafer 2, and the protective member is made of a thin plate material such as polyvinyl chloride plastic (PVC).

After performing the protective member bonding step, the first metal film removing step and the second metal film removing step are performed by irradiating the laser light from the side of the metal film 24 coated on the back surface 20b of the sapphire substrate 20 to the first metal film removing step. Corresponding to the region of the first dividing line 221, the metal film 24 is removed along the first dividing line 221 to form a first laser processing groove, and the second metal film removing step is to irradiate the laser light from the sapphire. The metal film 24 side of the back surface 20b of the substrate 20 is irradiated to a region corresponding to the second division planned line 222, and the metal film 24 is removed along the second division planned line 222, thereby forming a second laser processing groove. The first metal film removing step and the second metal film removing step are carried out using the laser processing apparatus 3 shown in FIG. The laser processing apparatus 3 shown in FIG. 3 includes a chuck table 31 for fixing a workpiece, and a laser light irradiation mechanism for irradiating laser light to a workpiece fixed to the chuck table 31. 32. A photographing mechanism 33 that photographs a workpiece to be fixed on the chuck table 31. The chuck table 31 is configured to be capable of attracting and fixing a workpiece, and is moved by a processing conveyance mechanism (not shown) to a machining advance direction indicated by an arrow X in FIG. 3, and is advanced by cutting not shown. The mechanism moves toward the cutting advance direction indicated by an arrow Y in FIG.

The above-described laser beam irradiation mechanism 32 includes a cylindrical outer casing 321 which is disposed substantially horizontally. A pulsed laser oscillator (not shown) and a pulsed laser oscillating mechanism having a repeating frequency setting mechanism are disposed in the casing 321. The front end portion of the outer casing 321 is provided with a concentrator 322 for collecting the pulsed laser light oscillated by the pulsed laser oscillating mechanism. The laser light irradiation unit 32 is provided with a light collecting point position adjusting mechanism (not shown) for adjusting the pulse laser light collected by the concentrator 322. The spot position of the light.

The photographing mechanism 33 attached to the front end portion of the outer casing 321 constituting the laser light irradiation unit 32 is irradiated with infrared rays to the image pickup unit (CCD) which is photographed by visible light in the illustrated embodiment. The infrared illuminating mechanism of the processed object, the optical system for capturing the infrared ray irradiated by the infrared illuminating mechanism, and the photographic element (infrared CCD) outputting the electric signal corresponding to the infrared ray captured by the optical system, and the like The signal is sent to a control mechanism not shown. Further, in the memory of the control unit (not shown), the coordinate values (design values) of the plurality of first division planned lines 221 and the plurality of second division planned lines 222 are stored with reference to the notch 201, and the coordinate values are set. As shown in the above first embodiment, the optical element layer (the epitaxial layer) 21 formed on the surface 20a of the sapphire substrate 20 of the optical element wafer 2 is formed.

In order to perform the first metal film removing step and the second metal film removing step using the laser processing apparatus 3, as shown in FIG. 3, the sapphire which has been adhered to the optical element wafer 2 is placed on the chuck table 31. The protective tape T side of the surface 20a of the substrate 20. Then, the optical element wafer 2 is fixed to the chuck table 31 through the protective tape T by a suction mechanism (not shown) (wafer fixing step). Therefore, the optical element wafer 2 fixed to the chuck table 31 is coated on the back surface 20b of the sapphire substrate 20 to be the upper side.

After the wafer fixing step is performed, the chuck table 31 that sucks and fixes the optical element wafer 2 is positioned directly under the photographing mechanism 33 by a processing advancement mechanism (not shown). Once the chuck table 31 is positioned directly below the photographing mechanism 33, a calibration operation is performed, and the calibration operation confirms whether the optical element wafer 2 has been positioned by the photographing mechanism 33 and a control mechanism not shown. The coordinate value. That is, the photographing unit 33 photographs the notch 201 formed on the outer circumference of the sapphire substrate 20 constituting the optical element wafer 2, and transmits the image signal to a control unit (not shown). Next, the control unit (not shown) determines whether the notch 201 is located at a predetermined coordinate value based on the image signal sent from the photographing unit 33, and if the notch 201 is not at the predetermined coordinate value, the chuck table 31 is rotated to perform adjustment. The notch 201 is positioned at a predetermined coordinate value, and the first division planned line 221 and the second divided planned line 222 are detected from the design value (calibration step).

After the calibration step is performed as described above, the first metal film removing step and the second metal film removing step are performed. The first embodiment of the first metal film removing step and the second metal film removing step will be described with reference to FIGS. 4 and 5.

That is, as shown in Fig. 4(a), the laser light irradiation region where the concentrator 322 of the moving chuck table 31 to the lightning light irradiation mechanism 32 is located is one end of the predetermined first division planned line 221 (the The coordinate value corresponding to the left end of 4(a) is located directly below the concentrator 322 of the laser light illumination mechanism 32. Next, the laser beam is irradiated from the concentrator 322 of the laser beam irradiation unit 32, and the chuck table 31 is moved in the direction indicated by the arrow X1 in the fourth (a) figure at a predetermined machining advance speed. Further, as shown in FIG. 4(b), the other end of the first division planned line 221 (the right end in the fourth (b) diagram) reaches the position directly below the concentrator 322, and the irradiation of the pulsed laser light is stopped. And the movement of the chuck table 31 is stopped. In the first metal film removing step, the light-converging point P of the pulsed laser light is aligned with the vicinity of the upper surface of the metal film 24 covered by the back surface 20b of the sapphire substrate 20 constituting the optical element wafer 2 as shown in Fig. 4(a). . As a result, as shown in FIG. 4(b), the metal film 24 covered on the back surface 20b of the sapphire substrate 20 constituting the optical element wafer 2 can be removed from the region corresponding to the first division planned line 221 to form the first laser processing. Ditch (first metal film removal step) Step).

The first metal film removal engineering described above is carried out, for example, by the following processing conditions.

Laser light wavelength: 355nm

Repeat frequency: 40kHz

Average output: 0.5~2W (depending on the metal of the metal film 24)

Spot diameter: 50μm

Processing forward speed: 300mm / sec

In this manner, after the first metal film removing step is performed on all of the first divided planned lines 221 formed on the optical element wafer 2, the chuck stage 31 is rotated by 90 degrees. Then, the second metal film removing step is performed by irradiating the laser light to a region corresponding to the second dividing line 222 and removing the metal film 24 along the second dividing line 222, thereby forming the second metal film removing step. The second laser processing groove.

As shown in Fig. 5(a), the second metal film removing step moves the laser light irradiation region where the chuck table 31 to the concentrator 322 of the laser light irradiation unit 32 is located, and the predetermined second dividing line 222 is prepared. The coordinate value corresponding to one end (the left end in the fifth (a) diagram) is positioned directly below the concentrator 322 of the laser light irradiation mechanism 32. Next, the laser beam is irradiated from the concentrator 322 of the laser beam irradiation unit 32, and the chuck table 31 is moved in the direction indicated by the arrow X1 in the fifth (a) plane at a predetermined advance speed. When the region intersecting the first laser processing groove 241 formed in the first metal film removing step reaches the concentrator 322 directly, the irradiation of the pulsed laser light is stopped, and the first laser processing is performed. After the area where the groove 241 intersects is crossed directly below the concentrator 322, the pulse is again irradiated Rushing light. The illumination and the stop pulse laser light are repeated as shown in FIG. 5(b), and after the other end of the second division planned line 222 (the right end in the fifth (b) diagram) reaches directly below the concentrator 322, The irradiation of the pulsed laser light is stopped, and the movement of the chuck table 31 is stopped. In the second metal film removing step, the light-converging point P of the pulsed laser light is aligned with the upper surface of the metal film 24 covered by the back surface 20b of the sapphire substrate 20 constituting the optical element wafer 2 as shown in Fig. 5(a). . As a result, as shown in FIG. 5(c), the metal film 24 covered on the back surface 20b of the sapphire substrate 20 constituting the optical element wafer 2 can be excluded from the first laser processing formed in the first metal film removing step. The region corresponding to the second division planned line 222 is removed in the region where the groove 241 intersects, and the second laser processing groove 242 is formed (second metal film removing step). Further, the second laser processing groove 242 formed by the second metal film removing step may slightly overlap the first laser processing groove 241 as shown in the fifth (d), or as in the fifth (e) As shown in the figure, it can be slightly separated from the first laser processing groove 241.

In this manner, the second metal film removing step described above is performed along all of the second divided planned lines 222 formed on the optical element wafer 2. Further, the processing conditions of the second metal film removing step may be the same as those of the first metal film removing step.

As described above, in the second metal film removing step of the first embodiment, the region that intersects with the first laser processing groove 241 formed in the first metal film removing step is irradiated with the laser light, so that the laser light is not irradiated. Since the intersecting region is removed by the first laser processing groove 241, the pulsed laser light does not penetrate the sapphire substrate 20 and is irradiated to the optical element layer 21 formed on the surface 20a, thereby preventing damage to the optical element layer 21. .

Next, the first metal film removing step and the second metal film removing step will be described. The second embodiment is abrupt.

In the second embodiment, the first metal film removing step excludes the region where the region corresponding to the second dividing line 222 intersects to irradiate the laser light. In the first metal film removing step in the second embodiment, as shown in Fig. 6(a), the laser light irradiation region in which the chuck unit 31 to the concentrator 322 of the laser light irradiation unit 32 is moved is prepared and will be scheduled. The coordinate value corresponding to one end of the first division planned line 221 (the left end in the sixth (a) diagram) is positioned directly below the concentrator 322 of the laser light irradiation mechanism 32. Next, the laser beam is irradiated from the concentrator 322 of the laser beam irradiation unit 32, and the chuck table 31 is moved in the direction indicated by the arrow X1 in the sixth (a) drawing at a predetermined processing advance speed. In this manner, when the region intersecting the region corresponding to the second division planned line 222 reaches the concentrator 322 directly, the irradiation of the pulsed laser light is stopped, and the region corresponding to the second division planned line 222 is to be stopped. The pulsed laser light is again illuminated after the intersecting region passes directly below the concentrator 322. The irradiation and stop pulse laser light are repeatedly repeated as shown in FIG. 6(b), and the other end of the second division planned line 222 (the right end in the sixth (b) diagram) reaches the concentrator of the laser light irradiation mechanism 32. Immediately after 322, the irradiation of the pulsed laser light is stopped, and the movement of the chuck table 31 is stopped. In the first metal film removing step, the light-converging point P of the pulsed laser light is aligned with the vicinity of the upper surface of the metal film 24 covered by the back surface 20b of the sapphire substrate 20 constituting the optical element wafer 2 as shown in Fig. 6(a). . As a result, as shown in Fig. 6(b), the metal film 24 covered on the back surface 20b of the sapphire substrate 20 constituting the optical element wafer 2 can be excluded from the region intersecting the region corresponding to the second division planned line 222. The region corresponding to the first division planned line 221 is removed, and the first laser processing groove 241 is formed (first metal film removing step).

In this manner, after the first metal film removing step is performed along all of the first divided planned lines 221 formed on the optical element wafer, the chuck stage 31 is rotated by 90 degrees. Next, the second metal film removing step is performed, and the laser light is irradiated onto the field corresponding to the second dividing line 222, and the metal film 24 is removed along the second dividing line 222. This forms a second laser processing groove.

In the second metal film removing step in the second embodiment, as shown in Fig. 7(a), the laser light irradiation region where the concentrator 322 of the laser light irradiation mechanism 32 is moved is moved, and is scheduled. The coordinate value corresponding to one end of the second division planned line 222 (the left end in the seventh (a) diagram) is positioned directly below the concentrator 322 of the laser light irradiation mechanism 32. Next, the laser beam is irradiated from the concentrator 322 of the laser beam irradiation unit 32, and the chuck table 31 is moved in the direction indicated by the arrow X1 in the seventh (a) diagram at a predetermined machining advance speed. Further, as shown in FIG. 7(b), after the other end of the second division planned line 222 (the right end in the seventh (b) diagram) reaches the position directly below the concentrator 322 of the laser light irradiation mechanism 32, The irradiation of the pulsed laser light is stopped, and the movement of the chuck table 31 is stopped. In the first metal film removing step, the light-converging point P of the pulsed laser light is aligned with the vicinity of the upper surface of the metal film 24 covered by the back surface 20b of the sapphire substrate 20 constituting the optical element wafer 2 as shown in Fig. 7(a). . As a result, as shown in Fig. 7(b), the metal film 24 covered on the back surface 20b of the sapphire substrate 20 constituting the optical element wafer 2 is formed by removing the region corresponding to the second division planned line 222 to form the second laser. The groove 242 is processed (the second metal film removing step). In this manner, the second metal film removing step described above is performed along all of the second divided planned lines 222 formed on the optical element wafer 2.

As described above, the first metal film removing step in the second embodiment is When the pulsed laser light is irradiated in a region intersecting the region corresponding to the second division planned line 222, the pulsed laser light is irradiated to the region corresponding to the second division planned line 222 in the second metal film removal step. Since the metal film remains in the region intersecting the first laser processing groove 241 in the first metal film removing step, the pulsed laser light is not irradiated onto the optical element layer 21 formed on the surface 20a of the sapphire substrate 20, and can be prevented. Damage is caused to the optical element layer 21.

As described above, after the first metal film removing step and the second metal film removing step are performed, the reforming layer forming step is performed from the back surface 20b side of the sapphire substrate 20 along the first laser processing groove 241. The second laser processing groove 242 irradiates the sapphire substrate 20 with laser light having a penetrating wavelength, and inside the sapphire substrate 20, a modified layer is formed along the first laser processing groove 241 and the second laser processing groove 242. This reforming layer forming step is carried out using the laser processing apparatus 30 as shown in Fig. 8. The laser processing apparatus 30 shown in Fig. 8 has the same configuration as the laser processing apparatus 3 shown in Fig. 3 except for the pulsed laser light to be irradiated, and therefore the same reference numerals are given to the same elements. The description is omitted.

In order to perform the reforming layer forming step using the above-described laser processing apparatus 30, first, the surface of the sapphire substrate 20 constituting the optical element wafer 2 is placed on the chuck table 31 of the laser processing apparatus 30 shown in FIG. The protective tape of 20a has a T side, and the optical element wafer 2 has been subjected to a first metal film removing step and a second metal film removing step. Then, the optical element wafer 2 is fixed to the chuck table 31 through the protective tape T by a suction mechanism (not shown) (wafer fixing step). Therefore, the optical component wafer 2 fixed to the chuck table 31 is covered with blue. The metal film on the back surface 20b of the gem substrate 20 becomes the upper side.

After the wafer fixing step is performed, the chuck stage 31 that sucks and fixes the optical element wafer 2 is positioned directly under the photographing mechanism 33 by a processing advancement mechanism (not shown). Once the chuck table 31 is positioned directly below the photographing mechanism 33, a calibration operation is performed, and the calibration operation confirms whether the optical element wafer 2 has been positioned by the photographing mechanism 33 and a control mechanism not shown. Coordinate value. That is, the photographing unit 33 and the control unit (not shown) perform image processing such as pattern matching, and perform calibration (calibration step) of the laser beam irradiation position, and image processing such as pattern matching is performed by the above-described The first laser processing groove 241 of the metal film 24 covered on the back surface 20b of the sapphire substrate 20 constituting the optical element wafer 2 is formed by the metal film removing step, and the laser light is irradiated along the first laser processing groove 241. The position of the concentrator 322 of the laser light irradiation mechanism 32 is aligned. Further, the second laser processing groove 242 is similarly calibrated to the laser light irradiation position, and the second laser processing groove is formed on the sapphire substrate 20 constituting the optical element wafer 2 by the second metal film removing step. The metal film 24 covered on the back surface 20b.

As described above, the first laser processing groove 241 and the second laser processing groove 242 formed by the metal film 24 covered by the back surface 20b of the sapphire substrate 20 constituting the optical element wafer 2 fixed to the chuck unit 31 are detected. After the laser light irradiation position is calibrated, as shown in Fig. 9(a), the laser light irradiation area where the concentrator 322 of the laser light irradiation mechanism 32 is moved is moved, and the predetermined first laser processing groove 241 is set. One end (the left end in the figure 9(a)) is positioned directly below the concentrator 322 of the laser light irradiation mechanism 32. Further, the light-converging point P of the pulsed laser light is aligned with the central portion of the sapphire substrate 20 in the thickness direction. Next, one side from the spotlight The 322 irradiates the sapphire substrate 20 with pulsed laser light having a penetrating wavelength, and moves the chuck table 31 in a direction indicated by an arrow X1 in the ninth (a) drawing at a predetermined processing advance speed. Further, as shown in Fig. 9(b), the other end of the first laser processing groove 241 (the right end in the ninth (b) drawing) reaches the irradiation position of the concentrator 322 of the laser light irradiation unit 32, and then stops. The pulsed laser light is irradiated and the movement of the chuck table 31 is stopped. As a result, as shown in FIG. 9(b), the reforming layer 243 can be formed along the first laser processing groove 241 inside the sapphire substrate 20 constituting the optical element wafer 2. The modified layer 243 is formed as a molten resolidified layer.

The processing conditions in the step of forming the reforming layer 243 described above are set as follows.

Laser light wavelength: 1045nm

Repeat frequency: 100kHz

Average output: 0.3W

Spot diameter: ψ 1~2μm

Processing forward speed: 400mm / sec

In this manner, after the reforming layer forming step is performed along all of the first dividing planned lines 221 formed on the optical element wafer 2, the chuck table 31 is rotated by 90 degrees. Further, the reforming layer forming step is performed along all of the second division planned lines 222 formed by the optical element wafer 2.

The optical element wafer 2 which has been subjected to the above-described reforming layer forming step is ruptured along the first dividing line 221 and the second dividing line 222 which have formed the reforming layer 243 as the starting point of the fracture by applying an external force. , entering the wafer dividing step of dividing into optical elements.

2‧‧‧Light component wafer

2a‧‧‧ Surface of optical component wafer

20‧‧‧Sapphire substrate

20a‧‧‧Sapphire substrate surface

20b‧‧‧The back of the sapphire substrate

201‧‧‧ gap

21‧‧‧Light component layer

211‧‧‧n type nitride semiconductor layer

212‧‧‧p-type nitride semiconductor layer

221‧‧‧1st dividing line

222‧‧‧2nd dividing line

23‧‧‧Light components

24‧‧‧Metal film

241‧‧‧1st laser processing ditch

242‧‧‧2nd laser processing ditch

243‧‧‧Modified layer

3, 30‧‧ ‧ laser processing equipment

31‧‧‧ chuck table

32‧‧‧Laser light illumination mechanism

321‧‧‧Shell

322‧‧‧ concentrator

33‧‧‧Photography institutions

P‧‧‧ spotlight

T‧‧‧protective tape

X, X1‧‧‧Processing direction

Y‧‧‧ cutting direction

The first (a) and (b) drawings are processed by the processing method of the optical element wafer of the present invention. A perspective view of the optical element wafer and a cross-sectional view showing the display of the important portion.

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

Fig. 3 is a perspective view showing the essential part of the laser processing apparatus for the first metal film removing step and the second metal film removing step in the method for processing the optical element wafer of the present invention.

4(a) and 4(b) are explanatory views showing a first metal film removing step in the first embodiment in the method of processing an optical element wafer of the present invention.

The fifth (a) to (e) drawings are explanatory views showing the second metal film removing step in the first embodiment in the method of processing the optical element wafer of the present invention.

6(a) and 6(b) are explanatory views showing a first metal film removing step in the second embodiment in the method of processing an optical element wafer according to the present invention.

7(a) and 7(b) are explanatory views showing a second metal film removing step in the second embodiment in the method of processing an optical element wafer according to the present invention.

Fig. 8 is a perspective view of an important portion of a laser processing apparatus for performing a reforming layer forming step of the method for processing an optical element wafer of the present invention.

Figs. 9(a) and 9(b) are explanatory views showing the steps of forming a modified layer in the method of processing an optical element wafer of the present invention.

2‧‧‧Light component wafer

20‧‧‧Sapphire substrate

21‧‧‧Light component layer

222‧‧‧2nd dividing line

241‧‧‧1st laser processing ditch

242‧‧‧2nd laser processing ditch

31‧‧‧ chuck table

32‧‧‧Laser light illumination mechanism

322‧‧‧ concentrator

P‧‧‧ spotlight

X1‧‧‧Processing direction

Claims (3)

A method of processing an optical element wafer in which an optical element layer is laminated on a surface of a substrate, and is formed on a plurality of first division planned lines extending in a predetermined direction, and formed on the first division planned line The plurality of regions defined by the second dividing line in the intersecting direction form an optical element, and the back surface of the substrate is covered with a metal film. The processing method is characterized in that the first metal film removing step includes laser light. Irradiating the region corresponding to the first division planned line from the side of the metal film covering the back surface of the substrate, and removing the metal film along the first division planned line, thereby forming the first laser processing groove, and In the step of removing the metal film, the laser light is irradiated onto the metal film side coated on the back surface of the substrate, irradiated to a region corresponding to the second planned dividing line, and the metal film is removed along the second dividing line. In the second laser processing groove, the second metal film removing step excludes a region intersecting the first laser processing groove formed by the first metal film removing step to irradiate the laser light. A method of processing an optical element wafer in which an optical element layer is laminated on a surface of a substrate, and is formed on a plurality of first division planned lines extending in a predetermined direction, and formed on the first division planned line The plurality of regions defined by the second dividing line in the intersecting direction form an optical element, and the back surface of the substrate is covered with a metal film. The processing method is characterized in that the first metal film removing step includes laser light. The first laser processing groove is formed by irradiating the region corresponding to the first dividing planned line from the side of the metal film covering the back surface of the substrate, and removing the metal film along the first dividing line. And the second metal film removing step of irradiating the laser light to the region corresponding to the second planned dividing line from the side of the metal film coated on the back surface of the substrate, and removing the metal film along the second dividing line. Thereby, the second laser processing groove is formed; the first metal film removing step excludes the region intersecting the region corresponding to the second division planned line to irradiate the laser light. A method of processing an optical element wafer according to claim 1 or 2, wherein after performing the second metal film removing step, performing a reforming layer forming step from the back side of the substrate Laser light having a penetrating wavelength is irradiated onto the substrate along the first laser processing groove and the second laser processing groove, and the first laser processing groove and the second mine are along the inside of the substrate The processing groove forms a modified layer.