KR20110055395A - Processing method of optical device wafer - Google Patents

Abstract

PURPOSE: A method for processing an optical device wafer is provided to easily locate a light focusing point at a desired location, thereby forming an affected layer without an optical device layer. CONSTITUTION: A protection member(30) is adhered to the surface of an optical device wafer(2). A laser ray with a wavelength which includes transparency about a substrate(20) of the optical device wafer is irradiated along with a street(22) so that an affected layer(210) is formed on the other side of the substrate. The other side of the optical device wafer is ground to have a preset thickness. The optical device wafer is fractured along with the street and divided into individual optical devices.

Description

PROCESSING METHOD OF OPTICAL DEVICE WAFER

The present invention is directed to a wafer for dividing an optical device wafer in which a plurality of optical devices are stacked on a surface of a substrate and formed in a plurality of regions partitioned by a plurality of streets formed in a lattice shape. It relates to a processing method.

In the optical device manufacturing process, an optical device layer made of a gallium nitride compound semiconductor is laminated on the surface of a substantially disk-shaped sapphire substrate or a silicon carbide substrate, and the light emitting diode is divided into a plurality of regions partitioned by a plurality of streets formed in a lattice shape. An optical device such as a laser diode is formed to form an optical device wafer. And the optical device wafer is cut | disconnected along the street, and the area | region in which the optical device was formed is divided | segmented, and individual optical devices are manufactured.

Cutting along the street of the optical device wafer mentioned above is normally performed by the cutting apparatus called a dicer. This cutting device is provided with the chuck table which hold | maintains a to-be-processed object, the cutting means for cutting the workpiece hold | maintained by the said chuck table, and the cutting feed means which makes the chuck table and cutting means move relatively. The cutting means includes a rotating spindle, a cutting blade mounted to the spindle, and a drive mechanism for rotationally driving the rotating spindle. The cutting blade includes a disk-shaped base and an annular cutting blade mounted on the side outer periphery of the base. The cutting blade has a thickness of about 20 μm by fixing diamond abrasive grains having a particle diameter of about 3 μm to the base by electroforming, for example. Formed.

By the way, since the sapphire substrate, silicon carbide substrate, etc. which comprise an optical device wafer have a high Mohs hardness, the cutting by the said cutting blade is not necessarily easy. In addition, since the cutting blade has a thickness of about 20 µm, the distance for partitioning the device requires about 50 µm in width. For this reason, the area ratio which a street occupies becomes high and there exists a problem that productivity is bad.

In order to solve the above-mentioned problem, as a method of dividing an optical device wafer along a street, a laser processing groove serving as a starting point of fracture is formed by irradiating a pulsed laser beam having absorptivity with respect to the wafer along the street, A method of dividing by applying an external force along a street on which a laser processing groove as a starting point is formed is proposed (see Patent Document 1, for example).

By the way, when a laser beam is formed by irradiating a laser beam along the street formed on the surface of the sapphire substrate which comprises an optical device wafer, the outer periphery of optical devices, such as a light emitting diode, will abrasion and brightness will fall, and an optical device There is a problem that the quality of is lowered.

In order to solve such a problem, the laser beam of the wavelength which has a permeability with respect to a sapphire substrate from the back surface side of the sapphire substrate in which the light emitting layer (epi layer) as an optical device layer is not formed is located inside a condensing point, and is located along the street. The following patent document 2 discloses a processing method of a sapphire substrate in which the sapphire substrate is divided along the street on which the deterioration layer is formed by irradiating and forming a deterioration layer along the street inside the sapphire substrate.

[Patent Document 1] Japanese Patent Application Laid-Open No. 10-305420 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-6492

In the method of dividing a wafer disclosed in Patent Document 2, first, the back surface of the wafer is ground in order to make the wafer into a predetermined thickness (for example, 100 μm or less), and then a pulsed laser beam having a transmittance to the wafer is applied to the wafer. The condensing point is set inside from the back side of the light source and irradiated along the street to form a deterioration layer that is the starting point of fracture along the street inside the wafer, but when the deteriorating layer reaches the light emitting layer (epi layer) as the optical device layer, the optical device The layer is damaged and the brightness of the optical device is lowered. In order to solve this problem, it is necessary to form a deterioration layer in the range which does not reach an optical device layer. By the way, it is very difficult to form a deterioration layer in the range which does not reach an optical device layer in the thin state that the thickness of a wafer is 100 micrometers or less.

This invention was made | formed in view of the said fact, The main technical subject is the optical device which can easily form a deterioration layer in the range which does not reach an optical device layer, and can form the thickness of an optical device to predetermined thickness. It is providing the processing method of a wafer.

In order to solve the above main technical problem, according to the present invention, an optical device wafer having an optical device formed on a plurality of regions partitioned by a plurality of streets formed by lattice and having an optical device layer laminated on the surface of the substrate, As a method of processing an optical device wafer to be divided into individual optical devices,

A protective member adhesion step of adhering the protective member to the surface of the optical device wafer,

A laser beam of a wavelength having a transmittance with respect to the substrate of the optical device wafer is irradiated along the street from a back side of the substrate to a light collecting point located inside the substrate, and deteriorated along the street on the back side of the substrate rather than the optical device layer. A deterioration layer forming step of forming a layer,

A back surface grinding step of grinding the back surface of the substrate of the optical device wafer subjected to the altered layer formation step to form a predetermined thickness;

Processing of an optical device wafer, comprising a wafer breaking step of applying an external force to the optical device wafer subjected to the back surface grinding process, breaking the optical device wafer along a street on which the deterioration layer is formed, and dividing the optical device wafer into individual optical devices. A method is provided.

In the altered layer forming step, the altered layer is formed on the rear surface side from a position of 20 to 60 µm from the substrate surface of the optical device wafer.

The protective member adhering step is performed by adhering the surface of the optical device wafer to a protective tape as a protective member attached to an annular frame, and backing the deteriorated layer forming step and backside in a state where the surface of the optical device wafer is adhered to the protective tape. Process and wafer breaking process are performed.

After the wafer breaking step is performed, a damaged layer removing step of grinding the back surface of the substrate of the optical device wafer to remove the damaged layer is performed.

The protective member adhering step is performed by adhering the surface of the optical device wafer to a protective tape as a protective member attached to an annular frame, and backing the deteriorated layer forming step and backside in a state where the surface of the optical device wafer is adhered to the protective tape. The process, the wafer breaking process, and the denatured layer removal process are performed.

In the present invention, the altered layer forming step is performed in a thick state before grinding the back surface of the substrate constituting the optical device wafer to form a predetermined thickness, so that the condensing point of the laser beam can be easily positioned at a desired position. It is possible to form a deterioration layer without damaging the optical device layer.

In the present invention, after performing the altered layer forming step, the back surface grinding process is performed to form the thickness of the optical device wafer to a predetermined thickness, and the optical device wafer is broken along the street on which the altered layer is formed. The thickness of can be suppressed to a minimum and the productivity is improved.

1 is a perspective view and an enlarged sectional view of an essential part showing an optical device wafer as a wafer;
Fig. 2 is a perspective view showing a state in which a protective member adhesion step in the method for processing an optical device wafer according to the present invention is performed and the surface of the wafer is adhered to a protective tape attached to an annular frame.
3 is a perspective view of an essential part of a laser processing apparatus for performing a deterioration layer forming step in a method of processing an optical device wafer according to the present invention.
4 is an explanatory diagram of a deterioration layer forming step in a processing method of an optical device wafer according to the present invention.
5 is an explanatory diagram of a back surface grinding step in the method for processing an optical device wafer according to the present invention.
It is sectional drawing which expands and shows the principal part of the optical device wafer in which the back surface grinding process was performed in the manufacturing method of the optical device wafer by this invention.
7 is a perspective view of a wafer breaking device for performing a wafer breaking step in the method of processing an optical device wafer according to the present invention.
8 is an explanatory diagram of a wafer breaking step in the optical device wafer processing method according to the present invention.
9 is an explanatory diagram of a deterioration layer removal step in the processing method of the optical device wafer according to the present invention.
It is sectional drawing which expands and shows the principal part of the optical device wafer in which the deterioration layer removal process was performed in the manufacturing method of the optical device wafer which concerns on this invention.
11 is an explanatory diagram of a wafer movement step in the method for processing an optical device wafer according to the present invention.
12 is a perspective view of a pickup device for carrying out a pick-up step in the method for processing an optical device wafer according to the present invention.
Fig. 13 is an explanatory diagram of a pickup step in the processing method of the optical device wafer according to the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of the optical device wafer processing method by this invention is described in detail with reference to an accompanying drawing.

1 (a) and 1 (b) show a perspective view and an enlarged cross-sectional view of an optical device wafer processed according to the optical device wafer processing method according to the present invention. The optical device wafer 2 shown to FIG. 1A and FIG. 1B is a light emitting layer as an optical device layer which consists of nitride semiconductors on the surface 20a of the sapphire substrate 20 whose thickness is 430 micrometers, for example. (Epiary layer) 21 is laminated | stacked in thickness of 5-10 micrometers. An optical device 23 such as a light emitting diode, a laser diode, or the like is formed in a plurality of regions partitioned by a plurality of streets 22 in which the light emitting layer (epitaxial layer) 21 is formed in a lattice shape. Hereinafter, the processing method of dividing this optical device wafer 2 into individual optical devices 22 along the street 21 is demonstrated.

First, in order to protect the optical device formed in the surface of an optical device wafer, the protective member adhesion process of sticking a protective member to the surface of an optical device wafer is performed. That is, as shown in Fig. 2, the surface 2a of the optical device wafer 2 is adhered to the surface of the protective tape 30 as the protective member attached to the annular frame 3 formed of the metal material. In the illustrated embodiment, the protective tape 30 is coated with an acrylic resin paste having a thickness of about 5 μm on the surface of a sheet base material made of polyvinyl chloride (PVC) having a thickness of 100 μm. The glue which has the property that adhesive force falls by irradiating an ultraviolet-ray is used.

When the surface 2a of the optical device wafer 2 is adhered to the protective tape 30 attached to the annular frame 3 by performing the above-mentioned protective member adhesion process, it has transparency to the substrate of the optical device wafer. The alternating layer formation process of irradiating a laser beam of a wavelength from the back side of a board | substrate to the inside of a board | substrate and irradiating along a street, and forming a quality alteration layer along a street in the back side rather than an optical device layer inside a board | substrate is carried out. Conduct. This altered layer formation process is performed using the laser processing apparatus 4 shown in FIG. The laser processing apparatus 4 shown in FIG. 3 has the chuck table 41 which hold | maintains a to-be-processed object, and the laser beam irradiation means 42 which irradiates a laser beam to the workpiece | work hold | maintained on the said chuck table 41. FIG. And the imaging means 43 for imaging the workpiece held on the chuck table 41. The chuck table 41 is configured to attract and hold the workpiece, and can be moved in the machining feed direction indicated by the arrow X in FIG. 3 by a machining feeder (not shown). The conveying means can be made to move in the indexing conveyance direction shown by the arrow Y in FIG.

The laser beam irradiation means 42 includes a cylindrical casing 421 arranged substantially horizontally. In the casing 421, the pulse laser beam oscillation means provided with the pulse laser beam oscillator which is not shown in figure, and a repetition frequency setting means is arrange | positioned. At the distal end of the casing 421, a condenser 422 for condensing the pulsed laser beam oscillated from the pulsed laser beam oscillation means is mounted. Moreover, the laser beam irradiation means 42 is provided with condensing point position adjusting means (not shown) for adjusting the condensing point position of the pulsed laser beam condensed by the condenser 422.

The imaging means 43 attached to the distal end portion of the casing 421 constituting the laser beam irradiation means 42 is constituted by an imaging device (CCD) or the like for imaging with visible light in the illustrated embodiment. The captured image signal is sent to control means (not shown).

Using the laser processing apparatus 4 mentioned above, the laser beam of wavelength having transparency with respect to the sapphire substrate 20 which comprises the said optical device wafer 2 is condensed from the back surface 20b side of the sapphire substrate 20. A dot is positioned inside the sapphire substrate 20 and irradiated along the street 22 to form a deteriorated layer along the street 22 on the rear surface 20b side of the light emitting layer (epi layer) 21 as the optical device layer. The altered layer forming step will be described with reference to FIGS. 3 and 4.

First, the protective tape 30 to which the optical device wafer 2 adhered is mounted on the chuck table 41 of the laser processing apparatus 4 shown in FIG. 3 mentioned above. And the optical device wafer 2 is hold | maintained on the chuck table 41 via the protective tape 30 (wafer holding process) by operating the suction means which is not shown in figure. Therefore, as for the optical device wafer 2 hold | maintained by the chuck table 41, the back surface 20b of the sapphire substrate 20 becomes an upper side. In addition, in FIG. 3, although the annular frame 3 with which the protection tape 30 was attached is abbreviate | omitted and shown, the annular frame 3 is hold | maintained by the suitable frame holding means arrange | positioned at the chuck table 41. In addition, in FIG. It is. In this way, the chuck table 41 which sucks and holds the optical device wafer 2 is located directly under the imaging means 43 by a processing conveyance means (not shown).

When the chuck table 41 is located directly under the imaging means 43, the alignment operation for detecting the processing area to be subjected to laser processing of the wafer 2 is executed by the imaging means 43 and control means (not shown). do. That is, the imaging means 43 and the control means which are not shown are laser beam irradiation means which irradiates a laser beam along the street 22 formed in the predetermined direction of the optical device wafer 2, and the said street 22. As shown in FIG. Image processing such as pattern matching for performing alignment with the light collector 422 of (42) is executed to perform alignment of the laser beam irradiation position (alignment process). In addition, alignment of the laser beam irradiation position is similarly performed with respect to the street 22 formed in the optical device wafer 2 in the direction orthogonal to the said predetermined direction. At this time, although the surface of the light emitting layer (epilayer) 21 in which the street 22 in the optical device wafer 2 is formed is located below, the sapphire substrate 20 constituting the optical device wafer 2 is formed. Since it is a transparent body, the street 22 can be picked up from the back surface 20b side of the sapphire substrate 20.

The street 22 formed in the surface of the light emitting layer (epilayer) 21 which comprises the optical device wafer 2 hold | maintained on the chuck table 41 as mentioned above is detected, and the alignment of a laser beam irradiation position is carried out. Is performed, the chuck table 41 is moved to the laser beam irradiation area where the light collector 422 of the laser beam irradiation means 42 is located, as shown in FIG. One end (the left end in FIG. 4A) of is placed directly below the light collector 422 of the laser beam irradiation means 42. And the condensing point P of the pulsed laser beam irradiated from the condenser 422 is moved from the surface 20a (lower surface) of the sapphire substrate 20 which comprises the optical device wafer 2, for example, to the position of 55 micrometers upper side. Fit. In order to position the condensing point P of the pulsed laser beam irradiated from the condenser 422 at a predetermined position of the sapphire substrate 20 constituting the optical device wafer 2, for example, Japanese Patent Application Laid-Open No. 2009-63446 The height position of the upper surface of the optical device wafer 2 held on the chuck table 41 is detected by using the height position detection device of the workpiece held in the chuck table described in the following, and the detected optical device wafer 2 is detected. The condensing point P of the pulsed laser beam is positioned at a predetermined position by operating a condensing point position adjusting means (not shown) on the basis of the height position of the upper surface. Next, the chuck table 41 is predetermined in the direction indicated by the arrow X1 in FIG. 4A while irradiating the sapphire substrate 20 with a pulsed laser beam having a transmittance from the light collector 422. Allows to move at the machining feed rate. And as shown in FIG.4 (b), when the irradiation position of the condenser 422 of the laser beam irradiation means 42 reaches the position of the other end (right end in FIG.4 (b)) of the street 22, The irradiation of the pulsed laser beam is stopped and the movement of the chuck table 41 is stopped. As a result, in the sapphire substrate 20 constituting the optical device wafer 2, as shown in Figs. 4B and 4C, the deteriorated layer continuous along the street 22 is formed ( 210 is formed (denatured layer forming step). The altered layer 210 is formed on the back surface 20b (upper surface) side of the surface 20a (lower surface) of the sapphire substrate 20, that is, on the back surface 20b (upper surface) side than the light emitting layer (epilayer) 21. The above-described deterioration layer forming process is performed along all the streets 22 formed on the optical device wafer 2.

The processing conditions in the above-described altered layer forming step are set as follows, for example.

Light source: Yb laser: Ytterbium-doped fiber laser

Wavelength: 1045 nm

Repetition frequency: 100 kHz

Average power: 0.3 W

Condensing spot diameter: Φ1-1.5 ㎛

Machining feed rate: 400 mm / sec

When the above-described altered layer forming process is performed under the above processing conditions, the altered layer 210 having a thickness of about 50 μm is formed in the vertical direction around the light converging point P of the pulsed laser beam. Therefore, by performing the above-described altered layer forming process, the surface 20a (lower surface) of the sapphire substrate 20, that is, the rear surface 20b (upper surface) side than the position of 30 μm from the light emitting layer (epilayer) 21. A deteriorated layer 210 of about 50 μm is formed. In addition, the altered layer 210 formed inside the sapphire substrate 20 has a rear surface 20b from the surface 20a of the sapphire substrate 20, that is, the position 20 to 60 µm from the light emitting layer (epitaxial layer) 21. It is preferable to form on the side. As described above, in the altered layer forming step, since the altered layer 210 is formed within the sapphire substrate 20 within the range of not reaching the light emitting layer (epitaxial layer) 21, the light emitting layer (epi layer) serving as an optical device layer. 21 is not damaged. In addition, since the deterioration layer formation process is performed in the thick state (for example, 430 micrometers) before grinding the back surface and forming it in predetermined thickness, the sapphire substrate 20 which comprises the optical device wafer 2 is mentioned later, The condensing point P of the pulsed laser beam can be easily positioned at a desired position, so that the altered layer 210 can be formed without damaging the light emitting layer (epilayer) 21 which is an optical device layer.

After the above-described deterioration layer forming step, the back surface grinding step of grinding the back surface of the optical device wafer to form a predetermined thickness is performed. This back surface grinding process is performed using the grinding apparatus 5 shown in FIG. The grinding apparatus 5 shown in FIG. 5 is a grinding tool provided with the chuck table 51 which hold | maintains a workpiece | work, and the grinding grindstone 521 for grinding the workpiece hold | maintained by the said chuck table 51 ( 52). In addition, the chuck table 51 has a central portion holding the workpiece to be high, and an outer circumferential portion being formed lower than the central portion. In order to perform the said back grinding process using the grinding apparatus 5 comprised in this way, as shown in FIG. 5, the light in which the above-mentioned deterioration layer formation process was performed on the chuck table 51 of the grinding apparatus 5 was performed. On the chuck table 51 by loading the protective tape 30 side of the device wafer 2, loading the annular frame 3 on the outer periphery of the chuck table 51, and operating suction means (not shown). The optical device wafer 2 and the annular frame 3 are sucked and held. Therefore, as for the optical device wafer 2 hold | maintained on the chuck table 51, the back surface 20b of the sapphire substrate 20 becomes an upper side. In this way, if the optical device wafer 2 is attracted and held on the chuck table 51, the grinding tool 52 is rotated at, for example, 1000 rpm, while the chuck table 51 is rotated at, for example, 500 rpm. By contacting the back surface 20b of the sapphire substrate 20 constituting the optical device wafer 2, a predetermined amount is ground and transferred. As a result, the back surface 20b of the sapphire substrate 20 is ground, and the sapphire substrate 20 constituting the optical device wafer 2 is formed to a predetermined thickness (for example, 80 µm). As a result, the deteriorated layer 210 can be exposed to the back surface 20b of the sapphire substrate 20 constituting the optical device wafer 2 as shown in FIG. 6. In this manner, after performing the above-described deterioration layer forming step, the backside grinding step is performed to form the thickness of the wafer to a predetermined thickness, whereby the thickness of the deteriorating layer can be suppressed to a minimum, thereby improving productivity.

If the above-mentioned back surface grinding process was performed, the wafer breaking process which gives an external force to an optical device wafer, breaks a wafer along the street in which the altered layer was formed, and divides into individual optical devices is performed. This wafer breaking step is performed using the wafer breaking device 6 shown in FIG. The wafer crushing apparatus 6 shown in FIG. 7 is provided with the base 61 and the movement table 62 arrange | positioned so that the movement to the direction shown by the arrow Y on the base 61 is possible. The base 61 is formed in rectangular shape, and the two guide rails 611 and 612 are arrange | positioned in parallel to each other in the direction shown by the arrow Y on the upper surface of both sides. The movement table 62 is arrange | positioned on these two guide rails 611 and 612 so that a movement is possible. The movement table 62 can be made to move to the direction shown by the arrow Y by the movement means 63. FIG. On the movable table 62, frame holding means 64 for holding the annular frame 3 is arranged. The frame holding means 64 includes a cylindrical main body 641, an annular frame holding member 642 provided at an upper end of the main body 641, and fixing means disposed on an outer circumference of the frame holding member 642. A plurality of clamps 643 are included. The frame holding means 64 configured in this way fixes the annular frame 3 mounted on the frame holding member 642 with the clamp 643. In addition, the wafer rupture apparatus 6 shown in FIG. 7 is provided with the rotation means 65 which makes the said frame holding means 64 rotate. The rotation means 65 includes a pulse motor 651 disposed on the movement table 62, a pulley 652 attached to a rotation shaft of the pulse motor 651, the pulley 652 and a cylindrical main body. And an endless belt 653 wound around 641. The rotating means 65 configured as described above rotates the frame holding means 64 through the pulley 652 and the endless belt 653 by driving the pulse motor 651.

The wafer breaking device 6 shown in FIG. 7 is an optical device wafer 2 supported by an annular frame 3 held by the annular frame holding member 642 via a protective tape 30. ) Is provided with tension imparting means (66) for exerting a tensile force in a direction orthogonal to the street (22). The tension applying means 66 is disposed in the annular frame holding member 642. This tension provision means 66 is equipped with the 1st suction holding member 661 and the 2nd suction holding member 662 which have a rectangular holding surface long in the direction orthogonal to the arrow Y direction. A plurality of suction holes 661a are formed in the first suction holding member 661, and a plurality of suction holes 662a are formed in the second suction holding member 662. The plurality of suction holes 661a and 662a communicate with suction means (not shown). In addition, the 1st suction holding member 661 and the 2nd suction holding member 662 can be made to move to arrow Y direction by the movement means not shown, respectively.

The wafer breaking device 6 shown in FIG. 7 is an optical device wafer 2 supported by an annular frame 3 held by the annular frame holding member 642 via a protective tape 30. Detection means 67 for detecting the street 22 of (). The detection means 67 is attached to the L-shaped support pillar 671 disposed on the base 61. This detection means 67 is comprised with an optical system, an imaging element (CCD), etc., and is arrange | positioned in the upper position of the said tension provision means 66. As shown in FIG. The detection means 67 comprised in this way is the street of the optical device wafer 2 supported by the annular frame 3 hold | maintained at the said annular frame holding member 642 via the protective tape 30. As shown in FIG. An image of 22 is converted into an electrical signal and sent to a control means (not shown).

Wafer breaking performed using the above-described wafer breaking device 6 will be described with reference to FIG. 8.

The annular frame 3 which supports the optical device wafer 2 in which the alteration layer formation process as a break origin formation process mentioned above was performed through the protective tape 30 is shown to FIG. 8A. Similarly, it is mounted on the frame holding member 642 and fixed to the frame holding member 642 by the clamp 643. Next, the moving means 63 is operated to move the moving table 62 in the direction indicated by the arrow Y (see FIG. 7), and as shown in FIG. 8A, the optical device wafer 2. Holding surface and first suction holding member of first suction holding member 661 constituting tension applying means 66 for one street 22 (the leftmost street in the illustrated embodiment) formed in a predetermined direction on the side. It is located between holding surfaces of 662. At this time, the detection means 67 captures the street 22, and performs alignment between the holding surface of the first suction holding member 661 and the holding surface of the second suction holding member 662. In this way, if one street 22 is positioned between the holding surface of the first suction holding member 661 and the holding surface of the second suction holding member 662, the suction means (not shown) is operated to obtain the suction hole ( By applying negative pressure to 661a and 662b, the optical device wafer 2 is provided on the holding surface of the first suction holding member 661 and the holding surface of the second suction holding member 662 via a protective tape 30. Is sucked and maintained (maintenance step).

After the above-described holding step is performed, a moving means (not shown) constituting the tension applying means 66 is operated, so that the first suction holding member 661 and the second suction holding member 662 are shown in Fig. 8B. As shown in the figure, the movement is performed in a direction away from each other. As a result, a tensile force acts on the street 22 located between the holding surface of the first suction holding member 661 and the holding surface of the second suction holding member 662 in a direction orthogonal to the street 22. In the optical device wafer 2, the deteriorated layer 210 formed on the sapphire substrate 20 is broken along the street 22 as a starting point of breaking (breaking step). By performing this breaking process, the protective tape 30 is extended slightly. In this breaking process, since the deterioration layer 210 is formed along the street 22 and the intensity | strength is reduced, the optical device wafer 2 has the 1st suction holding member 661 and the 2nd suction holding member ( By moving the 662 by about 0.5 mm in the direction away from each other, the deteriorated layer 210 formed on the sapphire substrate 20 of the optical device wafer 2 can be broken along the street 22 as a starting point of breakage.

If the breaking process of breaking along one street 22 formed in the predetermined direction as mentioned above was performed, the optical device wafer 2 by the above-mentioned 1st suction holding member 661 and the 2nd suction holding member 662 was performed. Release suction). Next, the moving means 63 is operated to move the moving table 62 in the direction indicated by the arrow Y (see FIG. 7) by the minute corresponding to the distance between the streets 22, and performs the breaking step. The street 22 next to (22) is positioned between the holding surface of the first suction holding member 661 constituting the tension applying means 66 and the holding surface of the second suction holding member 662. Then, the holding step and the breaking step are performed.

As described above, when the above holding step and the breaking step have been performed for all the streets 22 formed in the predetermined direction, the rotating means 65 is operated to rotate the frame holding means 64 by 90 degrees. As a result, the optical device wafer 2 held by the frame holding member 642 of the frame holding means 64 also rotates by 90 degrees, which is formed in a predetermined direction and is orthogonal to the street 22 where the breaking process is performed. The street 22 formed in the direction is positioned in parallel with the holding surface of the first suction holding member 661 and the holding surface of the second suction holding member 662. Next, by performing the above-described holding process and breaking process for all the streets 22 formed in the direction orthogonal to the street 22 where the breaking process is performed, the optical device wafer 2 is along the street 22. It is divided into individual optical devices 23.

After the above-described wafer breaking step is performed, the deteriorated layer removing step of grinding the back surface of the optical device wafer to remove the deteriorated layer is performed. This deterioration layer removal process is performed using the grinding apparatus 5 shown in the said FIG. That is, as shown in Fig. 9, the optical device wafer 2 (divided into individual optical devices 23) subjected to the above-described wafer breaking process on the chuck table 51 of the grinding apparatus 5 is applied. On the optical device wafer 2 on the chuck table 51 by loading the protective tape 30 side, loading the annular frame 3 on the outer circumference of the chuck table 51, and actuating suction means (not shown). And retains the annular frame 3 by suction. Therefore, as for the optical device wafer 2 hold | maintained on the chuck table 51, the back surface 20b of the sapphire substrate 20 becomes an upper side. In this way, if the optical device wafer 2 is attracted and held on the chuck table 51, the grinding tool 52 is rotated at, for example, 1000 rpm, while the chuck table 51 is rotated at, for example, 500 rpm. By contacting with the back surface 20b of the sapphire substrate 20 constituting the optical device wafer 2, a predetermined amount is ground and transported to a position where the deteriorated layer 210 is removed. As a result, the back surface 20b of the sapphire substrate 20 which comprises the optical device wafer 2 is ground, and the deterioration layer which remained in the side surface of the optical device 23 divided | segmented individually as shown in FIG. 210 can be removed. In this way, the deterioration layer 210 remaining on the side of the optical device 23 divided separately can be removed, thereby improving the brightness of the optical device 23.

After performing the above-described deterioration layer removal process, the back surface of the optical device wafer divided into individual optical devices is adhered to the surface of the protective tape attached to the annular frame, and the protective tape having the surface of the optical device wafer adhered thereto. A wafer transfer step of peeling the 30 to remove the annular frame 3 is performed. In this wafer movement step, as shown in Fig. 11A, a protective tape 30 (optical device wafer 2 divided into individual optical devices 23) mounted on an annular frame 3 is provided. Adhered to] is irradiated with ultraviolet rays from the ultraviolet irradiator 300. As a result, the adhesive pool of the protective tape 30 can harden | cure, and adhesive force may fall. Next, as shown in FIG. 11B, the back surface of the sapphire substrate 20 constituting the optical device wafer 2 adhered to the protective tape 30 attached to the annular frame 3 ( 20b) (the upper surface in FIG. 11 (b)) is adhered to the surface (lower surface in FIG. 11 (b)) of the protective tape 30a attached to the annular frame 3a. In addition, the annular frame 3a and the protection tape 30a should just be the structure similar to the said annular frame 3 and the protection tape 30. FIG. Next, as shown in FIG. 11 (c), the optical device wafer 2 (divided into individual optical devices 23) having a surface adhered to the protective tape 30 is provided with the protective tape 30. Peel off from. At this time, since the ultraviolet-ray is irradiated to the protective tape 30, the adhesive paste of the protective tape 30 hardens | cures, and adhesive force is reduced as shown to FIG. 11 (a), the optical device wafer 2 (individually) Divided into the optical device 23] can be easily peeled from the protective tape 30. Then, by removing the annular frame 3 on which the protective tape 30 is attached, the surface of the protective tape 30a attached to the annular frame 3a as shown in FIG. The optical device wafer 2 divided into individual devices is moved. As described above, the wafer transfer step includes the above-described deterioration layer process, the back surface grinding process, the wafer breaking process, and the deterioration layer removal process in a state in which the surface of the wafer is adhered to the protective tape 30 attached to the annular frame 3. Since the optical device wafer 2 is divided into individual devices 23, the optical tape is mounted on the annular frame 3a by inverting the front and rear surfaces of the optical device wafer 2 without breaking it. 30a). Therefore, the conduction test of the optical device 23 is performed in the state which replaced the optical device wafer 2 divided | segmented into each optical device 23 to the protective tape 30a attached to the annular frame 3a. can do.

If the wafer movement process was performed as mentioned above, the pick-up process of peeling and picking up the optical device divided | segmented individually from the protective tape which adhere | attached on the surface of the protective tape attached to the annular frame is performed. This pickup process is performed using the pickup device 7 shown in FIG. The pick-up apparatus 7 shown in FIG. 12 is attached to the frame holding means 71 holding the said annular frame 3a, and the annular frame 3a hold | maintained by the said frame holding means 71. As shown in FIG. The tape extension means 72 which expands the said protective tape 30a, and the pickup collet 73 are provided. The frame holding means 71 includes an annular frame holding member 711 and a plurality of clamps 712 as fixing means arranged on the outer circumference of the frame holding member 711. The upper surface of the frame holding member 711 forms a mounting surface 711a for loading the annular frame 3a, and the annular frame 3a is mounted on the mounting surface 711a. The annular frame 3a mounted on the mounting surface 711a is fixed to the frame holding member 711 by the clamp 712. The frame holding means 71 configured as described above is supported by the tape expansion means 72 so as to be able to move forward and backward.

The tape expansion means 72 is provided with the expansion drum 721 arrange | positioned inside the said annular frame holding member 711. The expansion drum 721 is smaller than the inner diameter of the annular frame 3a, and is mounted on the optical device wafer 2 (divided into individual optical devices 23) mounted on the annular frame 3a. It has an inner diameter and an outer diameter larger than the outer diameter of. Moreover, the expansion drum 721 is provided with the support flange 722 at the lower end. The tape expansion means 72 in the shown embodiment is provided with the support means 723 which can advance and retract the said annular frame holding member 711 in an up-down direction. The support means 723 comprises a plurality of air cylinders 723a disposed on the support flange 722, the piston rod 723b of which is connected to the lower surface of the annular frame holding member 711. do. As described above, in the supporting means 723 including the plurality of air cylinders 723a, the loading surface 711a has an expansion drum 721 having an annular frame holding member 711 as shown in FIG. It moves up and down between the reference position which becomes substantially the same height as the upper end of (), and the expansion position of the predetermined amount lower than the upper end of the expansion drum 721 as shown to (b) of FIG.

The pick-up process performed using the pick-up apparatus 7 comprised as mentioned above is demonstrated with reference to FIG. That is, as shown in Fig. 13A, the annular frame 3a on which the outer protective tape 30a to which the optical device wafer 2 (divided into individual devices) is adhered is mounted. It mounts on the mounting surface 711a of the frame holding member 711 which comprises the frame holding means 71, and is fixed to the frame holding member 711 by the clamp 712 (frame holding process). At this time, the frame holding member 711 is located at the reference position shown in Fig. 13A. Next, a plurality of air cylinders 723a as the support means 723 constituting the tape expansion means 72 are operated to extend the annular frame holding member 711 in FIG. 13B. To descend. Therefore, since the annular frame 3a fixed on the mounting surface 711a of the frame holding member 711 also descends, as shown in FIG. 13B, the annular frame 3a is attached to the annular frame 3a. The mounted protective tape 30a can be brought into contact with the upper edge of the expansion drum 721 (tape expansion process). As a result, since the optical device wafer 2 adhering to the protective tape 30a is divided into individual optical devices 23 along the street 21, the space between the individual devices 23 becomes wider and is spaced. (S) is formed. In this state, the pick-up collet 73 is operated to adsorb and hold the surface (upper surface) of the optical device 23, and to pick up by peeling off the protective tape 30a. At this time, as shown in Fig. 13B, the optical device 23 is pushed up by the push-up needle 74 from the lower side of the protective tape 30a, thereby bringing the optical device 23 into the protective tape 30a. It can be easily peeled from. Since the push-up needle 74 acts on the back surface of the optical device 23 and pushes it up, the surface of the optical device 23 is not damaged. Moreover, in the pick-up process, since the clearance gap S between each optical device 23 is widened as mentioned above, it can pick up easily, without contacting the adjacent optical device 23. In this way, the optical device 23 picked up by the pickup collet 73 is retained by the surface (upper surface), and there is no need to reverse the front and back of the optical device 23 thereafter.

As mentioned above, although demonstrated based on embodiment which showed this invention, this invention is not limited only to embodiment, A various deformation | transformation is possible in the range of the meaning of this invention. For example, in the above-described embodiment, although the tensile force acts in a direction orthogonal to the street on which the deterioration layer is formed as the starting point of the break as a wafer breaking step, the wafer is broken along the street on which the deterioration layer is formed. As a process, for example, as disclosed in Japanese Patent Laid-Open No. 2006-107273 or Japanese Patent Laid-Open No. 2006-128211, a bending stress is applied along a street to a wafer whose strength has decreased along the street, thereby producing a wafer. Other breaking methods, such as breaking along the street, may be used.

2: optical device wafer 20: sapphire substrate
21: Light emitting layer (epi layer) as optical device layer 3: Ring-shaped frame
30: masking tape 4: laser processing device
41: chuck table of the laser processing apparatus 42: laser beam irradiation means
422 condenser 5: grinding device
51: chuck table of the grinding device 52: grinding tool
6: wafer breaking device 66: tensioning means
7: pickup device 82: tape expansion means
73: pickup collet

Claims (5)

Optical device wafer processing method which divides an optical device wafer in which the optical device is laminated | stacked on the surface of the board | substrate, and the optical device was formed in the several area | region partitioned along the some street formed in the grid | lattice form into individual optical devices along the street. As
A protective member adhesion step of adhering the protective member to the surface of the optical device wafer,
A laser beam of a wavelength having a transmittance with respect to the substrate of the optical device wafer is irradiated along the street from a back side of the substrate to a light collecting point located inside the substrate, and deteriorated along the street on the back side of the substrate rather than the optical device layer. A deterioration layer forming step of forming a layer,
A back surface grinding step of grinding the back surface of the substrate of the optical device wafer subjected to the altered layer formation step to form a predetermined thickness;
Wafer breaking step of applying an external force to the optical device wafer subjected to the back grinding process, breaking the optical device wafer along the street on which the deterioration layer is formed, and dividing the optical device wafer into individual optical devices.
Process for processing an optical device wafer comprising a. The processing method of an optical device wafer according to claim 1, wherein the deterioration layer forming step forms a deterioration layer on the back side of the optical device wafer from a position of 20 to 60 µm from the surface of the substrate. The said protective member adhesion process of Claim 1 or 2 adhere | attaches the surface of an optical device wafer to the protective tape as a protective member attached to the annular frame, and adhere | attached the surface of an optical device wafer to the said protective tape. And processing the deteriorated layer forming step, the back surface grinding step and the wafer breaking step in a state. The optical device wafer processing method according to claim 1 or 2, wherein after the wafer breaking step is performed, a damaged layer removing step of grinding the back surface of the substrate of the optical device wafer to remove the damaged layer is performed. The said protection member adhesion process of Claim 4 adhere | attaches the surface of an optical device wafer to the protective tape as a protective member mounted to an annular frame, and the said quality change in the state which stuck the surface of the optical device wafer to the said protective tape. And a layer forming step, the back grinding step, the wafer breaking step, and the deterioration layer removal step.

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