JP4377717B2 - Wafer division method - Google Patents

Description

  The present invention relates to a wafer dividing method for dividing a wafer having a predetermined dividing line formed on a surface thereof in a lattice shape along the scheduled dividing line.

  In the semiconductor device manufacturing process, a plurality of regions are partitioned by dividing lines called streets arranged in a lattice pattern on the surface of a substantially disc-shaped semiconductor wafer, and circuits such as ICs, LSIs, etc. are partitioned in these partitioned regions. Form. Then, by cutting the semiconductor wafer along the planned dividing line, the region where the circuit is formed is divided to manufacture individual semiconductor chips. In addition, an optical device wafer in which a gallium nitride compound semiconductor or the like is laminated on the surface of a sapphire substrate is also divided into optical devices such as individual light-emitting diodes and laser diodes by cutting along a predetermined division line. Widely used.

  The cutting along the division lines such as the above-described semiconductor wafer and optical device wafer is usually performed by a cutting device called a dicer. This cutting apparatus includes a chuck table for holding a workpiece such as a semiconductor wafer or an optical device wafer, a cutting means for cutting the workpiece held on the chuck table, and a chuck table and the cutting means. And a cutting feed means for moving it. The cutting means includes a rotary spindle, a cutting blade mounted on the spindle, and a drive mechanism that rotationally drives the rotary spindle. The cutting blade is composed of a disk-shaped base and an annular cutting edge mounted on the outer periphery of the side surface of the base. The cutting edge is fixed to the base by electroforming, for example, diamond abrasive grains having a particle size of about 3 μm. It is formed to a thickness of about 20 μm.

  However, since the sapphire substrate, the silicon carbide substrate, etc. have high Mohs hardness, cutting with the cutting blade is not always easy. Furthermore, since the cutting blade has a thickness of about 20 μm, the dividing line that divides the device needs to have a width of about 50 μm. For this reason, for example, in the case of a device having a size of about 300 μm × 300 μm, there is a problem that the area ratio occupied by the street is 14% and the productivity is poor.

On the other hand, in recent years, as a method for dividing a plate-like workpiece such as a semiconductor wafer, a pulse laser beam that uses a pulsed laser beam that is transparent to the workpiece and aligns the condensing point inside the region to be divided is used. A laser processing method for irradiating the film has also been attempted. In the dividing method using this laser processing method, a pulse laser beam in an infrared light region having a light-transmitting property with respect to the work piece is irradiated from the one surface side of the work piece to the inside, and irradiated. The workpiece is divided by continuously forming a deteriorated layer along the planned division line inside the workpiece and applying external force along the planned division line whose strength has been reduced by the formation of this modified layer. To do. (For example, refer to Patent Document 1.)
Japanese Patent No. 3408805

  As described above, as a method of applying an external force along a division line of a wafer in which a deteriorated layer is continuously formed along the division line as described above and dividing the wafer into individual chips, the present applicant applies the wafer to the wafer. Japanese Patent Application No. 2003-361471 has proposed a technique for dividing a wafer into individual chips by expanding the attached protective tape and applying a tensile force to the wafer.

  Thus, in the method of applying a tensile force to the wafer by expanding the protective tape to which the wafer is attached, the tensile force is not sufficiently transmitted to the entire region of the wafer, particularly to the central region, and the wafer is applied to all the division lines. It may not be divided along, and is not necessarily satisfactory in terms of reliability.

  The present invention has been made in view of the above-mentioned facts, and its main technical problem is that a deteriorated layer is formed by irradiating a laser beam along a predetermined division line inside the wafer, and the efficiency is improved along the deteriorated layer. It is an object of the present invention to provide a wafer dividing method capable of dividing the wafer well and surely.

In order to solve the above main technical problem, according to the present invention, a wafer processing method for dividing a wafer along a predetermined division line formed in a lattice shape,
A deteriorated layer forming step of irradiating the wafer with a pulsed laser beam having transparency to the dividing line and forming a deteriorated layer along the dividing line inside the wafer;
A protective tape attaching step for adhering one surface of the wafer to the surface of an extensible protective tape attached to an annular frame before the altered layer forming step or after the altered layer forming step; ,
An external force is applied by pressing the pressing means along the planned dividing line passing through the central area of the wafer attached to the surface of the protective tape attached to the annular frame, and the wafer crosses through the central area. A block forming step of dividing the block into a plurality of blocks along the planned dividing line ;
A protective tape extending step of dividing the wafer along the planned dividing line by expanding the protective tape to which the wafer is adhered after the block forming step is performed.
A method of dividing a wafer is provided.

  In the block forming step, it is desirable to apply an external force to the division planned lines that intersect through the central region of the wafer to divide the wafer into four or more blocks.

In the present invention, a deteriorated layer is formed in the wafer along the planned division line by irradiating the wafer with a pulse laser beam having transparency to the wafer, and the wafer in which the modified layer is formed is formed. Before extending the stretchable protective tape attached to one side of the wafer, an external force is applied by pressing the pressing means along the planned dividing line passing through the center area of the wafer, and the wafer is moved to the center area. since it divided into a plurality of blocks along the dividing lines intersecting through, since the tensile force acting on the protective tape can be sufficiently transmitted to the center region of the wafer, dividing the wafer efficiently and reliably Can do.

  Preferred embodiments of a wafer dividing method according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 shows a perspective view of a semiconductor wafer as a wafer to be divided according to the present invention. A semiconductor wafer 10 shown in FIG. 1 is made of, for example, a silicon wafer having a thickness of 300 μm. A plurality of division lines 101 are formed in a lattice shape on the surface 10 a and are partitioned by the plurality of division lines 101. Circuits 102 are formed in a plurality of regions. Hereinafter, a dividing method for dividing the semiconductor wafer 10 into individual semiconductor chips will be described.

  In order to divide the semiconductor wafer 10 into individual semiconductor chips, a pulsed laser beam having transparency to the wafer is irradiated along the planned division line, and an altered layer is formed along the planned division line inside the wafer. An altered layer forming step is performed. This deteriorated layer forming step is performed using a laser processing apparatus 1 shown in FIGS. A laser processing apparatus 3 shown in FIGS. 2 to 4 includes a chuck table 11 that holds a workpiece, a laser beam irradiation unit 12 that irradiates a workpiece held on the chuck table 11 with a laser beam, and a chuck table 11. An image pickup means 13 for picking up an image of the work piece held on is provided. The chuck table 11 is configured to suck and hold a workpiece, and can be moved in a machining feed direction indicated by an arrow X and an index feed direction indicated by an arrow Y in FIG. Yes.

  The laser beam irradiation means 12 includes a cylindrical casing 121 disposed substantially horizontally. As shown in FIG. 3, a pulse laser beam oscillation means 122 and a transmission optical system 123 are disposed in the casing 121. The pulse laser beam oscillating means 122 includes a pulse laser beam oscillator 122a composed of a YAG laser oscillator or a YVO4 laser oscillator, and a repetition frequency setting means 122b attached thereto. The transmission optical system 123 includes an appropriate optical element such as a beam splitter. A condenser 124 containing a condenser lens (not shown) composed of a combination lens that may be in a known form is attached to the tip of the casing 121. The laser beam oscillated from the pulse laser beam oscillating means 122 reaches the condenser 124 through the transmission optical system 123, and a predetermined condensing spot diameter is applied to the workpiece held on the chuck table 11 from the condenser 124. Irradiated with D. As shown in FIG. 4, when the focused laser beam is irradiated with a pulse laser beam having a Gaussian distribution through the objective lens 124a of the condenser 124 as shown in FIG. 4, D (μm) = 4 × λ × f / (π × W ), Where λ is defined by the wavelength (μm) of the pulse laser beam, W is the diameter (mm) of the pulse laser beam incident on the objective lens 124a, and f is the focal length (mm) of the objective lens 124a.

  In the illustrated embodiment, the image pickup means 13 mounted on the tip of the casing 121 constituting the laser beam irradiation means 12 emits infrared rays to the workpiece in addition to a normal image pickup device (CCD) that picks up an image with visible light. Infrared illumination means for irradiating, an optical system for capturing infrared light emitted by the infrared illumination means, an image pickup device (infrared CCD) for outputting an electrical signal corresponding to the infrared light captured by the optical system, and the like Then, the captured image signal is sent to the control means described later.

The deteriorated layer forming step performed using the laser processing apparatus 1 described above will be described with reference to FIGS. 2, 5, and 6.
In this deteriorated layer forming step, first, the semiconductor wafer 10 is placed on the chuck table 11 of the laser processing apparatus 1 shown in FIG. 2 with the back surface 10b facing up, and the semiconductor wafer 10 is sucked and held on the chuck table 11. To do. The chuck table 11 that sucks and holds the semiconductor wafer 2 is positioned directly below the imaging means 13 by a moving mechanism (not shown).

  When the chuck table 11 is positioned immediately below the image pickup means 13, an alignment operation for detecting a processing region to be laser processed of the semiconductor wafer 10 is executed by the image pickup means 13 and a control means (not shown). That is, the image pickup means 13 and the control means (not shown) are a division line 101 formed in a predetermined direction of the semiconductor wafer 10, and a condenser 124 of the laser beam irradiation means 12 that irradiates a laser beam along the division line 101. Image processing such as pattern matching is performed to align the laser beam, and alignment of the laser beam irradiation position is performed. Similarly, the alignment of the laser beam irradiation position is also performed on the division line 101 formed on the semiconductor wafer 10 and extending at right angles to the predetermined direction. At this time, the surface 10a on which the planned division line 101 of the semiconductor wafer 10 is formed is located on the lower side, but the imaging means 13 corresponds to the infrared illumination means, the optical system for capturing infrared rays and the infrared rays as described above. Since an image pickup unit configured with an image pickup device (infrared CCD) or the like that outputs an electric signal is provided, it is possible to pick up an image of the planned division line 101 through the back surface 2b.

  As described above, when the division line 101 formed on the semiconductor wafer 10 held on the chuck table 11 is detected and the laser beam irradiation position is aligned, it is shown in FIG. In this way, the chuck table 11 is moved to the laser beam irradiation region where the condenser 124 of the laser beam irradiation means 12 for irradiating the laser beam is located, and one end (the left end in FIG. 5A) of the predetermined division line 11 is irradiated with the laser beam. Positioned just below the light collector 124 of the means 12. Then, the chuck table 11, that is, the semiconductor wafer 10 is moved at a predetermined feed speed in the direction indicated by the arrow X 1 in FIG. 5A while irradiating a transmissive pulse laser beam from the condenser 124. Then, as shown in FIG. 5B, when the irradiation position of the condenser 124 of the laser beam irradiation means 12 reaches the position of the other end of the division planned line 101, the irradiation of the pulse laser beam is stopped and the chuck table 11, that is, The movement of the semiconductor wafer 10 is stopped. In this deteriorated layer forming step, the condensing point P of the pulse laser beam is matched with the vicinity of the surface 10a (lower surface) of the semiconductor wafer 2, thereby exposing the surface 10a (lower surface) and changing the layer 110 from the surface 10a toward the inside. Is formed. This altered layer 110 is formed as a melt-resolidified layer.

The processing conditions in the deteriorated layer forming step are set as follows, for example.
Light source: LD excitation Q switch Nd: YVO4 laser wavelength: 1064 nm pulse laser Pulse output: 10 μJ
Condensing spot diameter: φ1μm
Pulse width: 100 nsec
Peak power density at the focal point; 1.3 × 10 ¹⁰ W / cm ²
Repetition frequency: 400 kHz
Processing feed rate: 400mm / sec

  When the thickness of the semiconductor wafer 2 is thick, the plurality of deteriorated layers 110 are formed by changing the condensing point P stepwise as shown in FIG. Form. For example, since the thickness of the deteriorated layer formed at one time is about 50 μm under the above-described processing conditions, in the illustrated embodiment, six deteriorated layers are formed on the wafer 10 having a thickness of 300 μm. . As a result, the altered layer 110 formed inside the semiconductor wafer 2 is formed from the front surface 10a to the back surface 10b along the planned dividing line 101.

  If the deteriorated layer 110 is formed along the planned dividing line 101 in the semiconductor wafer 10 by the above-described deteriorated layer forming process, one surface of the wafer is attached to the surface of the stretchable protective tape attached to the annular frame. The protective tape sticking process to stick is carried out. That is, as shown in FIG. 7, the back surface 10b of the semiconductor wafer 10 is adhered to the surface of the extensible protective tape 16 having the outer periphery mounted so as to cover the inner opening of the annular frame 15. In the embodiment shown in the drawing, the protective tape 16 has an acrylic resin paste of about 5 μm thick on the surface of a sheet base material made of polyvinyl chloride (PVC) having a thickness of 70 μm. You may implement this masking tape sticking process before implementing the deteriorated layer formation process mentioned above. That is, the above-described deteriorated layer forming step is performed in a state where the back surface 10 b of the semiconductor wafer 10 is faced up and the front surface 10 a is adhered to the protective tape 16 and supported by the annular frame 15.

  When the deteriorated layer forming step and the protective tape attaching step described above are performed, as shown in FIG. 8, they cross the central region of the wafer 10 attached to the surface of the protective tape 16 attached to the dicing frame 15. A block forming step is performed in which an external force is applied to the planned dividing line 101 to be divided into a plurality of blocks. In the embodiment shown in FIG. 8, an external force is applied to the two scheduled division lines 21 passing through the central region of the semiconductor wafer 10 to divide the semiconductor wafer 10 along the two scheduled division lines 21. The blocks 10A, 10B, 10C, and 10D are divided and formed. In this block forming step, it is desirable to divide the wafer 10 into four or more blocks.

Next, a wafer dividing apparatus for carrying out the block forming step and a protective tape expanding step described later will be described with reference to FIGS.
FIG. 9 shows a perspective view of the wafer dividing apparatus, and FIG. 10 shows an exploded perspective view of the main part of the dividing apparatus shown in FIG. The wafer dividing apparatus 2 in the illustrated embodiment includes a base 20, a first table 3 movably disposed on the base 20 in a direction indicated by an arrow Y, and the first table 3. The second table 4 is provided so as to be movable in a direction indicated by an arrow X orthogonal to the arrow Y. The base 20 is formed in a rectangular shape, and two guide rails 21 and 22 are arranged in parallel to each other in the direction indicated by the arrow Y on the upper surface of both side portions. Of the two guide rails, one guide rail 21 is formed with a guide groove 211 having a V-shaped cross section on the upper surface thereof.

  As shown in FIG. 10, the first table 3 is formed in a window frame shape having a rectangular opening 31 at the center. A guided rail 32 slidably fitted in a guide groove 211 formed in one guide rail 21 provided on the base 20 is provided on the lower surface of one side of the first table 3. It has been. Further, two guide rails 33 and 34 are arranged in parallel to each other on the upper surfaces of both side portions of the first table 3 in a direction perpendicular to the guided rail 32. Of the two guide rails, one guide rail 33 has a guide groove 331 having a V-shaped cross section on the upper surface thereof. As shown in FIG. 9, the first table 3 configured as described above fits the guided rail 32 in a guide groove 211 formed in one guide rail 21 provided in the base 20, and the other Is placed on the other guide rail 22 provided on the base 20. The wafer dividing apparatus 2 in the illustrated embodiment includes first moving means 35 that moves the first table 3 in the direction indicated by the arrow Y along the guide rails 21 and 22 provided on the base 2. ing. As shown in FIG. 10, the first moving means 35 includes a male screw rod 351 disposed in parallel to the other guide rail 22 provided on the base 20 and a male screw rod 351 disposed on the base 20. A bearing 352 that rotatably supports one end, a pulse motor 353 that is connected to the other end of the male screw rod 351 and rotationally drives the male screw rod 351, and is provided on the lower surface of the first table 3. It consists of a female screw block 354 to be screwed together. The first moving means 35 configured in this manner moves the first table 3 in the direction indicated by the arrow Y by driving the pulse motor 353 and rotating the male screw rod 351.

  The second table 4 is formed in a rectangular shape as shown in FIG. 10 and includes a circular hole 41 in the center. A guided rail 42 is slidably fitted in a guide groove 331 formed in one guide rail 33 provided on the first table 3 on the lower surface of one side portion of the second table 4. Is provided. As shown in FIG. 9, the second table 4 configured in this manner fits the guided rail 42 into a guide groove 331 formed in one guide rail 33 provided in the first table 3. At the same time, the lower surface of the other side is placed on the other guide rail 34 provided on the first table 3. The wafer dividing apparatus 2 in the illustrated embodiment includes second moving means 45 that moves the second table 4 in the direction indicated by the arrow X along the guide rails 33 and 34 provided on the first table 3. It has. As shown in FIG. 10, the second moving means 45 is disposed on the first table 3 and a male threaded rod 451 disposed in parallel to the other guide rail 34 provided on the first table 3. A bearing 452 that rotatably supports one end of the male screw rod 451, a pulse motor 453 that is connected to the other end of the male screw rod 451 and rotationally drives the male screw rod 451, and is provided on the lower surface of the second table 4. It consists of a female screw block 454 that is screwed into the male screw rod 451. The second moving means 45 configured as described above moves the second table 4 in the direction indicated by the arrow X by driving the pulse motor 453 and rotating the male screw rod 451.

  The wafer dividing apparatus 2 in the illustrated embodiment includes a frame holding means 5 for holding the annular dicing frame 15 and a tape for expanding the protective tape 16 attached to the dicing frame 15 held by the frame holding means 5. Expansion means 6 is provided. As shown in FIGS. 9 and 11, the frame holding means 5 includes an annular frame holding member 51 having an inner diameter larger than the diameter of the hole 41 provided in the second table 4, and an outer periphery of the frame holding member 51. It comprises a plurality of clamping mechanisms 52 as fixing means arranged. An upper surface of the frame holding member 51 forms a placement surface 511 on which the dicing frame 15 is placed, and the dicing frame 15 is placed on the placement surface 511. The annular frame 12 placed on the placement surface 511 is fixed to the frame holding member 51 by the clamp mechanism 52. The frame holding means 5 configured as described above is disposed above the hole 41 of the second table 4 and is supported by a tape expanding means 6 described later so as to advance and retreat in the vertical direction.

  As shown in FIGS. 9 and 11, the tape expansion means 6 includes an expansion drum 60 disposed inside the annular frame holding member 51. The expansion drum 60 has an inner diameter and an outer diameter that are smaller than the inner diameter of the annular frame 15 and larger than the outer diameter of the semiconductor wafer 10 attached to the protective tape 16 attached to the annular frame 15. The expansion drum 60 includes a mounting portion 61 that is rotatably fitted to an inner peripheral surface of a hole 41 provided in the second table 4 at a lower end portion, and an upper outer periphery of the mounting portion 61. The surface is provided with a support flange 62 that protrudes in the radial direction. The tape expansion means 6 in the illustrated embodiment includes support means 63 that can advance and retract the annular frame holding member 51 in the vertical direction. The support means 63 includes a plurality of air cylinders 630 disposed on the support flange 62, and the piston rod 631 is connected to the lower surface of the annular frame holding member 51. As described above, the support means 63 including the plurality of air cylinders 630 has a predetermined amount from the reference position where the mounting surface 511 is substantially flush with the upper end of the expansion drum 60 and the upper end of the expansion drum 60. Move up and down between the lower extended positions. Therefore, the support means 63 composed of a plurality of air cylinders 630 functions as expansion movement means for relatively moving the expansion drum 60 and the frame holding member 51 in the vertical direction.

  The wafer dividing apparatus 2 in the illustrated embodiment includes a rotating means 65 for rotating the expansion drum 60 and the frame holding member 51 as shown in FIG. The rotating means 65 includes a pulse motor 651 disposed on the second table 4, a pulley 652 attached to the rotation shaft of the pulse motor 651, the pulley 652, and a support flange 62 of the expansion drum 60. And an endless belt 653 wound around. The rotation means 65 configured in this manner rotates the expansion drum 60 via the pulley 652 and the endless belt 653 by driving the pulse motor 651.

  The wafer splitting device 2 in the illustrated embodiment has an external force along the planned split line 101 of the semiconductor wafer 10 supported by the annular frame 15 held by the annular frame holding member 51 via the protective tape 16. The pressing means 7 is provided as an external force applying means for causing the pressure to act. The pressing means 7 is disposed on the base 20 and is disposed in the expansion drum 60. As shown in FIG. 10, the pressing means 7 includes an air cylinder 71 disposed on the base 20 and a pressing member 73 provided at the tip of the piston rod 72 of the air cylinder 71. The front end of the pressing member 73 is formed in a spherical shape. The radius of the spherical shape of the pressing member 73 is set to 1 to 2 mm. The pressing means 7 configured in this way presses the scheduled division line 101 of the semiconductor wafer 10 when the air cylinder 71 is operated and the pressing member 73 provided at the tip of the piston rod 72 is positioned at a pressing position described later.

  Referring back to FIG. 9, the wafer dividing device 2 in the illustrated embodiment is a semiconductor wafer supported on the annular frame 15 held by the annular frame holding member 51 via the protective tape 16. There are provided ten dividing lines 101 and detection means 8 for detecting individually divided chips, which will be described later. The detection means 8 is attached to an L-shaped support column 81 disposed on the base 20. The detection means 8 is composed of an optical system, an image sensor (CCD), and the like, and is disposed above the pressing means 7. The detection means 8 configured as described above is configured to divide the semiconductor wafer 10 supported by the annular frame 15 held by the annular frame holding member 51 via the protective tape 16 into the division line 101 and individually described later. The divided chip is imaged, converted into an electrical signal, and sent to a control means (not shown).

  Further, the wafer dividing apparatus 2 in the illustrated embodiment includes pickup means 9 for picking up individually divided chips described later from the protective tape 16. The pickup means 9 includes a turning arm 91 disposed on the base 2 and a pickup collet 92 attached to the tip, and the turning arm 91 is turned by driving means (not shown). Note that the swivel arm 91 is configured to be movable up and down, and the pickup collet 92 attached to the tip can pick up the chip attached to the protective tape 16.

The wafer dividing apparatus 2 in the illustrated embodiment is configured as described above, and the operation thereof will be described mainly with reference to FIGS.
As shown in FIG. 7, the annular frame 15 in which the semiconductor wafer 10 whose strength has been lowered along the planned dividing line 101 is supported via the protective tape 16 is held by the frame as shown in FIG. It is placed on the placement surface 511 of the frame holding member 51 constituting the means 5 and fixed to the frame holding member 51 by the clamp mechanism 52. At this time, the frame holding member 51 is positioned at the reference position shown in FIG.

  If the annular frame 15 supporting the semiconductor wafer 10 via the protective tape 16 is held by the frame holding member 51, the first moving means 35 and the second moving means 45 are operated to operate the first table 3. Is moved in the direction indicated by the arrow Y (see FIG. 9), and the second table 4 is moved in the direction indicated by the arrow X (see FIG. 9). As shown in FIG. One end (the left end in FIG. 12A) of a predetermined division line 101 formed in a predetermined direction is positioned at a position corresponding to the pressing member 73 of the pressing means 7. At this time, the predetermined division line positioned at the position corresponding to the pressing member 73 is set to the predetermined division line 101 passing through the central region of the semiconductor wafer in the division line formed in the semiconductor wafer 10 in the predetermined direction. Yes.

  Next, the air cylinder 71 of the pressing means 7 is actuated to raise the piston rod 72, and the pressing member 73 provided at the tip of the piston rod 72 as shown in FIG. Then, it is positioned at a pressing position where it presses against a predetermined division line 101 formed on the semiconductor wafer 10. Then, the second moving means 45 is operated to move the second table 4 in the direction indicated by the arrow X (see FIG. 9). Accordingly, since the frame holding member 51 and the tape expansion means 6 arranged on the second table 4 move in the direction indicated by the arrow X1 in FIG. 12B, the pressing member 73 moves through the central region of the semiconductor wafer. It moves relatively while pressing along a predetermined dividing line 101 passing through. As a result, since the deteriorated layer 110 is formed along the planned division line 101 and the strength is lowered, the semiconductor wafer 10 is easily divided into two blocks along the predetermined division line 101 (first). 1 block forming step).

  If the first block forming process is performed on the predetermined division line 101 passing through the central region of the semiconductor wafer in the division line formed in the predetermined direction of the semiconductor wafer 10 as described above, the rotating means The pulse motor 651 of 65 is rotationally driven to rotate the expansion drum 60 and the frame holding member 51 by 90 degrees. As a result, the semiconductor wafer 10 held by the frame holding member 51 also rotates 90 degrees. Next, the first moving means 35 and the second moving means 45 are operated to move the first table 3 in the direction indicated by the arrow Y (see FIG. 9), and the second table 4 is moved to the arrow. In the direction indicated by X (see FIG. 9), the pressing means 7 presses one end of the planned dividing line 101 formed in a direction perpendicular to the predetermined direction of the semiconductor wafer 10 as in the first block forming step described above. It is positioned at a position corresponding to the member 73. At this time, the predetermined division line positioned at the position corresponding to the pressing member 73 is set to the predetermined division line 101 passing through the central region of the semiconductor wafer in the division line formed in the semiconductor wafer 10 in the predetermined direction. Yes. Then, by performing the block formation step in the same manner as the first block formation step described above, the semiconductor wafer 10 is divided into predetermined divisions that pass through the central region of the semiconductor wafer in the division line that is formed in a direction perpendicular to the predetermined direction. Dividing along the planned line 101 (second block forming step). By carrying out the first block forming step and the second block forming step in this way, the wafer 10 is divided along two planned dividing lines 101 intersecting with each other as shown in FIG. The block is divided into four blocks 10A, 10B, 10C, and 10D.

If the first block forming step and the second block forming step described above are performed, the semiconductor wafer 10 is divided along each scheduled division line 101 by expanding the protective tape 16 to which the semiconductor wafer 10 is attached. A protective tape expansion process is performed. This protective tape expansion process will be described with reference to FIG.
When the first block forming step and the second block forming step are performed, the air cylinder 71 of the pressing means 7 is operated to lower the piston rod 72 as shown in FIG. Next, the plurality of air cylinders 630 as the support means 63 constituting the tape expansion means 6 are operated, and the annular frame holding member 51 is lowered to the expansion position shown in FIG. Accordingly, since the annular frame 15 fixed on the mounting surface 511 of the frame holding member 51 is also lowered, the protective tape 16 attached to the annular frame 15 is an expansion drum as shown in FIG. 60 abuts on the upper edge of 60 and is expanded. As a result, the tensile force acts radially on the semiconductor wafer 10 adhered to the protective tape 16. When a tensile force is applied to the semiconductor wafer 10 in a radial manner in this manner, the strength of the altered layer 110 formed along each scheduled division line 101 is reduced, so that the semiconductor wafer 10 breaks along the altered layer 110. And divided into individual semiconductor chips 120. At this time, the semiconductor wafer 10 is divided along the two division planned lines 101 intersecting the central region by performing the first block forming process and the second block forming process described above, and four blocks are formed. Since 10A, 10B, 10C, and 10D are divided and formed, the tensile force acting on the protective tape 16 is sufficiently transmitted to the central region of the semiconductor wafer 10, so that each of the planned dividing lines 101 on which the altered layer is formed is provided. It can be divided efficiently and reliably along. The expansion amount of the protective tape 16, that is, the extension amount in the protective tape expansion step can be adjusted by the downward movement amount of the frame holding member 51. When stretched, the semiconductor wafer 10 could be broken along the altered layer 110. Thereafter, the pickup means 9 shown in FIG. 9 is operated to pick up the chip 120 by the pickup collet 92 and transport it to a tray or die bonding process (not shown).

  Although the present invention has been described based on the illustrated embodiment, the present invention is not limited to the embodiment, and various modifications are possible within the scope of the gist of the present invention. In the embodiment described above, an example of dividing a semiconductor wafer made of a silicon wafer has been described. However, the present invention is applicable to the division of other wafers such as an optical device wafer in which a gallium nitride compound semiconductor is laminated on the surface of a sapphire substrate. can do. In the above-described embodiment, the example in which the block forming process and the protective tape expanding process are performed by the wafer dividing apparatus has been described. However, the block forming process and the protective tape expanding process may be performed by separate apparatuses. Good. In the block forming step, an example in which pressing means for pressing the semiconductor wafer along the planned dividing line is used as a method of applying an external force along the planned dividing line of the semiconductor wafer. As a method of applying an external force along the line, vibration may be applied using ultrasonic waves, or a heat shock may be applied by irradiating a laser beam.

1 is a perspective view of a semiconductor wafer divided by a wafer dividing method according to the present invention. The principal part perspective view of the laser processing apparatus which implements the deteriorated layer formation process of the division | segmentation method of the wafer by this invention. The block diagram which shows simply the structure of the laser beam irradiation means with which the laser processing apparatus shown in FIG. 2 is equipped. The simplification figure for demonstrating the condensing spot diameter of a pulse laser beam. Explanatory drawing of the altered layer formation process in the division | segmentation method of the wafer by this invention. Explanatory drawing which shows the state formed by laminating | stacking a deteriorated layer inside a wafer in the deteriorated layer formation process shown in FIG. The perspective view which shows the state which affixed the semiconductor wafer in which the deteriorated layer formation process was performed on the surface of the extendable protective tape with which the cyclic | annular flame | frame was mounted | worn. The perspective view which shows the state which implemented the block formation process to the semiconductor wafer shown in FIG. 1 is a perspective view of a wafer dividing apparatus for performing a block forming step and a protective tape expanding step in a wafer dividing method according to the present invention. The perspective view which decomposes | disassembles and shows the principal part of the dividing device shown in FIG. Sectional drawing which shows the 2nd table, frame holding means, and tape expansion means which comprise the division | segmentation apparatus shown in FIG. Explanatory drawing which shows the block formation process in the division | segmentation method of the wafer by this invention. Explanatory drawing which shows the protective tape expansion process in the division | segmentation method of the wafer by this invention.

Explanation of symbols

1: Laser processing device 11: Chuck table of laser processing device 21: Laser beam irradiation means 13: Imaging means 2: Wafer dividing device 20: Base 3: First table 4: Second table 5: Frame holding means 6 : Tape expansion means 60: Expansion drum 65: Turning means 7: Pressing means 8: Detection means 9: Pickup means 10: Semiconductor wafer 101: Scheduled division line 102: Circuit 110: Altered layer 120: Semiconductor chip 15: Dicing frame 16 : Protective tape

Claims (1)

A wafer processing method for dividing a wafer along a predetermined division line formed in a lattice shape,
A deteriorated layer forming step of irradiating the wafer with a pulsed laser beam having transparency to the dividing line and forming a deteriorated layer along the dividing line inside the wafer;
A protective tape attaching step of adhering one surface of the wafer to the surface of an extensible protective tape attached to an annular frame before the altered layer forming step or after the altered layer forming step; ,
An external force is applied by pressing the pressing means along the planned dividing line passing through the center area of the wafer attached to the surface of the protective tape attached to the annular frame, and the wafer crosses the center area. A block forming step of dividing the block into a plurality of blocks along the planned dividing line ;
A protective tape extending step of dividing the wafer along the planned dividing line by expanding the protective tape to which the wafer is adhered after performing the block forming step;
A wafer dividing method characterized by the above.

Images