JP2014011381A - Wafer processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer processing method capable of replacing a wafer with a dicing tape without damaging devices individually divided with a modified layer as a starting point.SOLUTION: The wafer processing method includes the steps of: sticking a protection member to a surface of a wafer 2; forming a modified layer inside the wafer 2; dividing the wafer 2 into individual devices 22 by grinding a rear surface of the wafer 2; sucking and holding the rear surface of the wafer 2 by a first suction and holding pad and carrying out the wafer from a grinding device; sucking and holding the protection member side by a second suction and holding pad with the protection member facing upward (a wafer replacement step); sticking a dicing tape 9 to the rear surface of the wafer 2; peeling the protection member; increasing a space s between the devices by expanding the dicing tape 9; and attaching an annular frame 11 to an adhesive surface of the dicing tape 9.

Description

  The present invention relates to a wafer processing method in which a wafer in which devices are formed in a plurality of regions partitioned by streets formed in a lattice shape on the surface is divided into individual devices along the streets.

  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 wafer-shaped semiconductor wafer, and devices such as ICs, LSIs, etc. are partitioned in the partitioned regions. Form. Then, the semiconductor wafer is cut along the streets to divide the region in which the device is formed to manufacture individual devices. 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 or silicon carbide substrate is also divided into optical devices such as individual light emitting diodes and laser diodes by cutting along the streets. Widely used.

  As a method of dividing the wafer along the street, a laser processing method has been attempted in which a pulsed laser beam having transparency to the wafer is used, and the focused laser beam is aligned within the region to be divided and irradiated with the pulsed laser beam. . The dividing method using this laser processing method is to irradiate the inside of the wafer with a pulsed laser beam having a wavelength that is transparent to the wafer by aligning the condensing point from one side of the wafer to the inside. A modified layer is continuously formed along the street, and an external force is applied along the street whose strength is reduced by the formation of the modified layer, thereby dividing the wafer into individual devices. (For example, refer to Patent Document 1.)

  In addition, a protective member is attached to the front surface of the wafer, a pulse laser beam having a wavelength that is transparent to the wafer is irradiated along the street from the back side of the wafer, and a modified layer is formed along the street inside the wafer. After forming, the protective member side of the wafer is held by the holding means of the grinding device, and the grinding wheel is rotated and pressed against the back surface of the substrate to form a substrate with a predetermined thickness and a modified layer is formed. A method of dividing along a street is proposed. (For example, see Patent Document 2.)

Japanese Patent No. 3408805 Japanese Patent No. 3762409

  Thus, the wafer divided into individual devices starting from the modified layer has a space between the devices close to 0, and is taken out of the grinding machine and replaced with dicing tape to pick up the individual devices. In addition, there is a problem that the corners of the devices are rubbed and damaged to deteriorate the quality.

  The present invention has been made in view of the above-mentioned facts, and the main technical problem thereof is a wafer processing method that can be replaced with a dicing tape without damaging the individually divided devices starting from the modified layer. It is to provide.

In order to solve the above-mentioned main technical problem, according to the present invention, a wafer processing method for dividing a wafer in which devices are formed in a plurality of regions partitioned by streets formed in a lattice shape on the surface along the streets. There,
A protective member attaching step for attaching a protective member to the surface of the wafer;
A modified layer forming step of irradiating a laser beam having a wavelength having transparency to the wafer from the back side of the wafer along the street, and forming a modified layer along the street inside the wafer;
The protective member side of the wafer is held by the holding means of the grinding device, and is ground by pressing the back surface of the wafer while rotating the grinding wheel to form the wafer with a predetermined thickness and on the street where the modified layer is formed. Grinding process to divide along the individual devices,
A wafer unloading step of sucking and holding the entire back surface of the wafer subjected to the grinding step with a first suction holding pad and unloading from the holding means of the grinding device;
The protection attached to the surface of the wafer on the second suction holding pad with the protective member attached to the surface of the wafer sucked and held on the first suction holding pad facing upward A wafer transfer step of sucking and holding the member side to separate the first suction holding pad from the wafer;
A dicing tape adhering step of adhering the adhesive surface of the dicing tape to the back surface of the wafer on which the protective member side is sucked and held by the second suction holding pad;
A wafer support step of supporting the wafer on which the dicing tape attaching step has been performed on a support table via the dicing tape and separating the second suction holding pad from the wafer;
A protective member peeling step for peeling off the protective member attached to the surface of the wafer on which the wafer supporting step has been performed;
A tape expansion step of expanding the interval between the devices by expanding the dicing tape attached to the wafer on which the protective member peeling step has been performed;
Attaching an annular frame having an opening having a size to accommodate the wafer subjected to the tape expansion process to the adhesive surface of the dicing tape, and attaching the wafer to the opening through the dicing tape Process,
A dicing tape cutting step for cutting the dicing tape corresponding to the annular frame,
A method for processing a wafer is provided.

After carrying out the tape expansion step, the supporting table supporting the wafer via the dicing tape is retracted, and the dividing step of completely dividing the wafer into individual devices by the dividing means from the dicing tape side;
A wafer re-supporting step of placing and supporting the dicing tape on the support table in an expanded state after performing the dividing step,
The annular frame mounting step is performed after the wafer re-supporting step.

  In the wafer processing method according to the present invention, the back surface of the wafer on which the modified layer is formed along the street is ground to form the wafer to a predetermined thickness, and each wafer is individually formed along the street on which the modified layer is formed. After carrying out the grinding step to divide into devices, the entire surface of the wafer divided into individual devices is sucked and held by the first suction holding pad, taken out from the holding means of the grinding apparatus, and a dicing tape is attached. Since the dicing tape is expanded and the interval between each device is widened, the annular frame is attached to the adhesive surface of the dicing tape, so the wafer divided into individual devices after carrying out the grinding process is taken out of the grinding machine and then dicing tape. The corners of the devices are not rubbed and damaged during the replacement.

The perspective view of the semiconductor wafer as a wafer divided | segmented by the processing method of the wafer by this invention. Explanatory drawing which shows the masking tape sticking process in the processing method of the wafer by this invention. The principal part perspective view of the laser processing apparatus for implementing the modified layer formation process in the processing method of the wafer by this invention. Explanatory drawing which shows the modified layer formation process in the processing method of the wafer by this invention. Explanatory drawing of the grinding process in the processing method of the wafer by this invention. Explanatory drawing of the wafer carrying-out process in the processing method of the wafer by this invention. Explanatory drawing of the wafer transfer process in the processing method of the wafer by this invention. Explanatory drawing of the dicing tape sticking process in the processing method of the wafer by this invention. Explanatory drawing of the wafer support process in the processing method of the wafer by this invention. Explanatory drawing of the protection member peeling process in the processing method of the wafer by this invention. Explanatory drawing of the tape expansion process in the processing method of the wafer by this invention. Explanatory drawing of the annular frame mounting process in the processing method of the wafer by this invention. Explanatory drawing of the dicing tape cutting process in the processing method of the wafer by this invention. Explanatory drawing of the division | segmentation process in the processing method of the wafer by this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a wafer processing method according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a perspective view of a semiconductor wafer as a wafer to be processed according to the present invention. A semiconductor wafer 2 shown in FIG. 1 is made of a silicon wafer having a thickness of, for example, 600 μm, and a plurality of streets 21 are formed in a lattice shape on the surface 2a, and a plurality of regions defined by the plurality of streets 21 are formed. Further, a device 22 such as an IC or LSI is formed. Hereinafter, a wafer processing method for dividing the semiconductor wafer 2 into individual devices 22 along the streets 21 will be described.

  First, in order to protect the device 22 formed on the surface 2 a of the semiconductor wafer 2, a protective member attaching step for attaching a protective member to the surface 2 a of the semiconductor wafer 2 is performed. That is, as shown in FIG. 2, a protective tape 3 as a protective member is attached to the surface 2a of the semiconductor wafer 2. In the illustrated embodiment, the protective tape 3 has an acrylic resin-based paste applied to the surface of a sheet-like substrate made of polyvinyl chloride (PVC) having a thickness of 100 μm to a thickness of about 5 μm.

  Next, the protective member side of the semiconductor wafer 2 is held on the chuck table of the laser processing apparatus, and a laser beam having a wavelength that is transmissive to the semiconductor wafer 2 from the back side of the semiconductor wafer 2 is focused on the inside. Irradiation along the street is performed, and a modified layer forming step is performed in which a modified layer is formed along the street inside the semiconductor wafer 2. This modified layer forming step is performed using a laser processing apparatus 4 shown in FIG. A laser processing apparatus 4 shown in FIG. 3 includes a chuck table 41 that holds a workpiece, laser beam irradiation means 42 that irradiates a workpiece held on the chuck table 41 with a laser beam, and a chuck table 41 that holds the workpiece. An image pickup means 43 for picking up an image of the processed workpiece is provided. The chuck table 41 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 application means 42 includes a cylindrical casing 421 arranged substantially horizontally. In the casing 421, a pulse laser beam oscillation means having a pulse laser beam oscillator or a repetition frequency setting means (not shown) composed of a YAG laser oscillator or a YVO4 laser oscillator is arranged. A condenser 422 for condensing the pulse laser beam oscillated from the pulse laser beam oscillating means is attached to the tip of the casing 421.

  In the illustrated embodiment, the imaging means 43 attached to the tip of the casing 421 constituting the laser beam irradiation means 42 emits infrared rays to the workpiece in addition to a normal imaging device (CCD) that captures images 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 a control means (not shown).

A modified layer forming step performed using the laser processing apparatus 4 described above will be described with reference to FIG.
In this modified layer forming step, first, the protective tape 3 side of the semiconductor wafer 2 is placed on the chuck table 41 of the laser processing apparatus 4 shown in FIG. Then, by operating a suction means (not shown), the semiconductor wafer 2 is sucked and held on the chuck table 41 via the protective tape 3 (wafer holding step). Therefore, the back surface 2b of the semiconductor wafer 2 held on the chuck table 41 is on the upper side. In this way, the chuck table 41 that sucks and holds the semiconductor wafer 2 is positioned directly below the imaging unit 43 by a processing feed unit (not shown).

  When the chuck table 41 is positioned immediately below the image pickup means 43, an alignment operation for detecting a processing region to be laser processed of the semiconductor wafer 2 is executed by the image pickup means 43 and a control means (not shown). That is, the imaging unit 43 and a control unit (not shown) align the street 21 formed in a predetermined direction of the semiconductor wafer 2 with the condenser 422 of the laser beam irradiation unit 42 that irradiates the laser beam along the street 21. Image processing such as pattern matching is performed to perform alignment of the laser beam irradiation position. The alignment of the laser beam irradiation position is similarly performed on the street 21 formed in the semiconductor wafer 2 and extending in a direction orthogonal to the predetermined direction. At this time, the surface 2a on which the street 21 of the semiconductor wafer 2 is formed is located on the lower side. However, as described above, the imaging unit 43 is an infrared illumination unit, an optical system for capturing infrared rays, and an electrical signal corresponding to infrared rays. Since the image pickup unit (infrared CCD) or the like is provided, the street 21 can be imaged through the back surface 2b.

  When the street 21 formed on the semiconductor wafer 2 held on the chuck table 41 is detected as described above and the laser beam irradiation position is aligned, as shown in FIG. The chuck table 41 is moved to the laser beam irradiation region where the condenser 422 of the laser beam irradiation means 42 for irradiating the laser beam is located, and one end of the predetermined street 21 (the left end in FIG. 4A) is collected by the laser beam irradiation means 42. It is positioned directly below the optical device 422. Next, the condensing point P of the pulsed laser beam irradiated from the concentrator 422 is aligned with the central portion in the thickness direction of the semiconductor wafer 2. Then, the chuck table 41 is moved at a predetermined feed speed in the direction indicated by the arrow X1 in FIG. 4A while irradiating a pulsed laser beam having a wavelength that is transparent to the silicon wafer from the condenser 422. 4B, when the irradiation position of the condenser 422 of the laser beam irradiation means 42 reaches the position of the other end of the street 21, the irradiation of the pulse laser beam is stopped and the chuck table 41 is moved. Stop. As a result, the modified layer 210 is formed along the street 21 inside the semiconductor wafer 2.

The processing conditions in the modified layer forming step are set as follows, for example.
Light source: LD excitation Q switch Nd: YVO4 laser Wavelength: 1064 nm pulse laser Repetition frequency: 100 kHz
Average output: 1W
Condensing spot diameter: φ1μm
Processing feed rate: 100 mm / sec

  When the modified layer forming process is performed along the predetermined street 21 as described above, the chuck table 41 is indexed and moved in the direction indicated by the arrow Y by the interval of the street 21 formed on the semiconductor wafer 2 (indexing process). The modified layer forming step is performed. When the modified layer forming step is performed along all the streets 21 formed in the predetermined direction as described above, the chuck table 41 is rotated 90 degrees to be aligned with the streets 21 formed in the predetermined direction. On the other hand, the modified layer forming step is performed along streets 21 extending in a direction orthogonal to the above.

  When the above-described modified layer forming step is performed, the protective tape 3 of the semiconductor wafer 2 is held by the holding means of the grinding device, and is ground by pressing against the back surface of the semiconductor wafer 2 while rotating the grinding wheel. A grinding process is performed in which 2 is formed to a predetermined thickness and is divided into individual devices along the street where the modified layer is formed. This grinding step is performed using a grinding apparatus 5 shown in FIG. A grinding apparatus 5 shown in FIG. 5 includes a chuck table 51 as a holding unit that holds a workpiece, and a grinding unit 52 that grinds the workpiece held on the chuck table 51. The chuck table 51 is configured to suck and hold the workpiece on the upper surface, and is rotated in a direction indicated by an arrow 51a in FIG. 5 by a rotation driving mechanism (not shown). The grinding means 52 includes a spindle housing 521, a rotating spindle 522 that is rotatably supported by the spindle housing 521 and rotated by a rotation driving mechanism (not shown), a mounter 523 attached to the lower end of the rotating spindle 522, and the mounter And a grinding wheel 524 attached to the lower surface of 523. The grinding wheel 524 includes an annular base 525 and a grinding wheel 526 that is annularly attached to the lower surface of the base 525, and the base 525 is attached to the lower surface of the mounter 523 with fastening bolts 527. ing.

  In order to carry out the grinding process using the grinding device 5 described above, the protective tape 3 side adhered to the surface of the semiconductor wafer 2 is placed on the upper surface (holding surface) of the chuck table 51 as shown in FIG. Put. Then, the semiconductor wafer 2 is sucked and held on the chuck table 51 via the protective tape 3 by a suction means (not shown) (wafer holding step). Accordingly, the back surface 2b of the semiconductor wafer 2 held on the chuck table 51 is on the upper side. If the semiconductor wafer 2 is sucked and held on the chuck table 51 via the protective tape 3 as described above, the grinding wheel of the grinding means 52 is rotated while the chuck table 51 is rotated in the direction indicated by the arrow 51a in FIG. 5 is rotated in the direction indicated by an arrow 524a in FIG. 5 at, for example, 6000 rpm, and the grinding wheel 526 is brought into contact with the back surface 2b of the semiconductor wafer 2 which is the processing surface as shown in FIG. As shown by an arrow 524b, a predetermined amount is ground and fed at a grinding feed rate of 1 μm / second, for example, downward (in a direction perpendicular to the holding surface of the chuck table 51). As a result, the back surface 2b of the semiconductor wafer 2 is ground to form the semiconductor wafer 2 with a predetermined thickness (for example, 100 μm), and individually along the streets 21 in which the modified layer 210 is formed and the strength is reduced. The device 22 is divided. In addition, since the protective tape 3 is affixed on the surface of the plurality of devices 22 divided into the individual devices 22, the form of the semiconductor wafer 2 is maintained without being separated.

  Next, a wafer unloading step is performed in which the back surface of the semiconductor wafer 2 on which the grinding step has been performed is sucked and held by the first suction holding pad and unloaded from the chuck table 51 as a holding means of the grinding device 5. This wafer unloading step is performed using the first suction holding pad shown in FIGS. 6 (a) and 6 (b). The first suction holding pad 6 shown in FIGS. 6A and 6B includes a disk-shaped base 61 and a pad 62. The base 61 constituting the first suction holding pad 6 is provided with a circular recess 611 whose lower part is opened. A pad 62 formed in a disc shape by a porous ceramic member is fitted into the recess 611. Thus, the lower surface of the pad 62 fitted into the recess 611 of the base 61 functions as a suction surface for sucking and holding the workpiece. A circular recess 611 formed in the base 61 constituting the first suction holding pad 6 is connected to suction means (not shown). Therefore, when a suction means (not shown) is operated, negative pressure is applied to the lower surface (suction surface) of the pad 62 through the recess 611 of the base 61, and the workpiece is suctioned to the lower surface (suction surface) of the pad 62. Can be held.

  In order to carry out the wafer carry-out process using the first suction holding pad 6 described above, the suction holding is released in the chuck table 51 as the holding means of the grinding device 5 as shown in FIG. The lower surface (suction surface) of the pad 62 of the first suction holding pad 6 is brought into contact with the back surface 2b (upper surface) of the semiconductor wafer 2 divided into the individual devices 22 in which the grinding process is performed, and suction means (not shown) is operated. Thus, the entire surface of the semiconductor wafer 2 divided into the individual devices 22 is sucked and held on the lower surface (suction surface) of the pad 62. The first suction holding pad 6 that sucks and holds the semiconductor wafer 2 on the lower surface (suction surface) of the pad 62 as described above is in a state where the semiconductor wafer 2 is sucked and held as shown in FIG. Is lifted from the upper surface of the chuck table 51 and unloaded from the chuck table 51. As described above, the entire surface of the semiconductor wafer 2 divided into the individual devices 22 is sucked and held by the first suction holding pad 6 and carried out from the chuck table 51, so that a grinding process is performed and divided into the individual devices 22. When the semiconductor wafer 2 is unloaded from the grinding apparatus 5, the corners of the device 22 are not rubbed and damaged, and the quality is not deteriorated.

  If the wafer unloading step described above is performed, the protective tape 3 which is a protective member attached to the surface of the semiconductor wafer 2 sucked and held by the first suction holding pad 6 is directed upward. A wafer transfer step is performed in which the second suction holding pad is caused to suck and hold the side of the protective tape 3 attached to the surface of the semiconductor wafer 2 to separate the first suction holding pad 6 from the semiconductor wafer 2. The wafer transfer process is performed using the second suction holding pad shown in FIGS. 7A and 7B. The second suction / holding pad 7 shown in FIGS. 7A and 7B includes a disk-shaped base 71 and a pad 72. The base 71 constituting the second suction holding pad 7 is provided with a circular recess 711 whose lower part is opened. A pad 72 formed in a disk shape by a porous ceramic member is fitted into the recess 711. In this way, the lower surface of the pad 72 fitted in the recess 711 of the base 71 functions as a suction surface for sucking and holding the workpiece. A circular recess 711 formed in the base 71 constituting the second suction holding pad 7 is connected to suction means (not shown). Accordingly, when a suction means (not shown) is operated, a negative pressure is applied to the lower surface (suction surface) of the pad 72 via the recess 711 of the base 71, and the workpiece is suctioned to the lower surface (suction surface) of the pad 72. Can be held.

  In order to perform the wafer transfer process using the second suction holding pad 7, the first suction holding pad 6 that has performed the wafer unloading process is turned upside down as shown in FIG. The protective tape 3 which is a protective member attached to the surface of the semiconductor wafer 2 held by suction is directed upward. Next, the first suction holding pad 6 is positioned and raised below the second suction holding pad 7, and the second suction holding pad 7 is placed on the upper surface of the protective tape 3 attached to the surface of the semiconductor wafer 2. After the lower surface (suction surface) of the pad 72 is brought into contact, the suction holding of the semiconductor wafer 2 by the first suction holding pad 6 is released. Then, by operating a suction means (not shown), the entire surface of the protective tape 3 adhered to the surface of the semiconductor wafer 2 is sucked and held on the lower surface (suction surface) of the pad 72 of the second suction holding pad 7. Then, as shown in FIG. 7B, the first suction holding pad 6 is lowered and separated from the semiconductor wafer 2. In this way, the second suction holding pad 7 that sucks and holds the protective tape 3 attached to the surface of the semiconductor wafer 2 on the lower surface (suction surface) of the pad 72 is the next process in the state where the semiconductor wafer 2 is sucked and held. Transport to.

  Next, a dicing tape adhering step is performed in which the adhesive surface of the dicing tape is adhered to the back surface of the semiconductor wafer 2 in which the protective tape 3 side is sucked and held by the second suction holding pad 7. That is, the dicing tape 9 is placed on the table 81 of the tape sticking device 8 as shown in FIG. As described above, the dicing tape 9 placed on the table 81 is provided with an adhesive layer on the surface (upper surface) to form an adhesive surface. With the dicing tape 9 thus placed on the table 81, the back surface 2b of the semiconductor wafer 2 in which the protective tape 3 side is sucked and held by the second suction holding pad 7 as shown in FIG. Is pressed against the adhesive surface which is the surface (upper surface) of the dicing tape 9. If the adhesive surface which is the surface (upper surface) of the dicing tape 9 is attached to the back surface 2b of the semiconductor wafer 2 on which the protective tape 3 side is sucked and held on the second suction holding pad 7 in this way, ( As shown in b), the second suction holding pad 7 is raised and moved to the side of the table 81, and the back surface (lower surface) of the dicing tape 9 in which the pressing roller 82 is adhered to the back surface 2b of the semiconductor wafer 2. By being pressed against the rear surface 2b of the semiconductor wafer 2, the adhesive surface which is the front surface (upper surface) of the dicing tape 9 is securely adhered.

  If the above-described dicing tape adhering step is performed, the wafer supporting step is performed in which the semiconductor wafer 2 is supported on the support table via the dicing tape 9 and the second suction holding pad 7 is separated from the semiconductor wafer 2. . That is, as shown in FIG. 9A, the second suction holding pad 7 holding the semiconductor wafer 2 to which the adhesive surface, which is the surface (upper surface) of the dicing tape 9, is held by the support table 10. The rear surface (lower surface) of the dicing tape 9 which is conveyed upward and is adhered to the rear surface 2 b of the semiconductor wafer 2 is placed on the support surface which is the upper surface of the support table 10. Then, as shown in FIG. 9B, the suction holding of the semiconductor wafer 2 by the second suction holding pad 7 is released, and the second suction holding pad 7 is separated from the semiconductor wafer 2. Thus, by supporting the semiconductor wafer 2 on the support table 10 via the dicing tape 9, the protective tape 3 adhered to the surface of the semiconductor wafer 2 is exposed to the upper side.

  When the wafer support process described above is performed, the protective tape 3 attached to the surface of the semiconductor wafer 2 supported on the support table 10 via the dicing tape 9 is peeled off as shown in FIG. Member peeling step). By peeling off the protective tape 3 in this way, the semiconductor wafer 2 supported on the support table 10 via the dicing tape 9 is in a state where the surface 2a is exposed upward.

  Next, a tape expansion step is performed to expand the interval between the devices by expanding the protective tape 3 attached to the surface of the semiconductor wafer 2 on which the protective member peeling step has been performed. That is, as shown in FIG. 11A, the dicing tape 9 (attached to the back surface of the semiconductor wafer 2 divided into individual devices) placed on the support table 10 is expanded in all directions. As a result, an interval (s) is formed between the individual devices 22 attached to the dicing tape 9 as shown in FIG.

  If the tape expansion process described above is performed, an annular frame having an opening size to accommodate the semiconductor wafer 2 subjected to the tape expansion process is mounted on the adhesive surface of the dicing tape 9 and the dicing tape 9 is interposed therebetween. Then, an annular frame mounting process for accommodating the semiconductor wafer 2 in the opening is performed. That is, as shown in FIGS. 12 (a) and 12 (b), the dicing tape 9 placed on the support table 10 is expanded and the annular frame having the opening 110 having a size for accommodating the semiconductor wafer 2 is used. 11 is attached to the adhesive surface of the dicing tape 9. As a result, as shown in FIG. 12B, the semiconductor wafer 2 in which the space (s) is formed between the individually divided devices 22 is accommodated in the opening 110 of the annular frame 11.

  If the annular frame mounting process described above is performed, a dicing tape cutting process for cutting the dicing tape 9 corresponding to the annular frame 11 is performed. That is, as shown in FIG. 13A, the dicing tape 9 to which the annular frame 11 is attached is cut from the back surface (lower surface) along the region surrounding the opening 110 of the annular frame 11 using the cutter 12. As a result, as shown in FIG. 13A and FIG. 13B, the semiconductor wafer 2 in which the space (s) is formed between the individually divided devices 22 is formed into an annular frame via the dicing tape 9. 11 is supported.

  As described above, the semiconductor wafer 2 in which the interval (s) is formed between the individually divided devices 22 by carrying out the tape expansion process is supported by the annular frame 11 via the dicing tape 9, so that While the semiconductor wafer 2 divided between the devices 22 is replaced with the dicing tape 9, the corners of the device 22 are not rubbed and damaged, and the quality is not deteriorated.

Next, another embodiment of the present invention will be described.
The protective tape 3 of the semiconductor wafer 2 on which the above-described modified layer forming step has been performed is held by holding means of a grinding device, and is ground by pressing the back surface of the semiconductor wafer 2 while rotating the grinding wheel. Even if a grinding process is performed in which the semiconductor wafer 2 is divided into individual devices along the street where the modified layer is formed, the semiconductor wafer 2 may not be divided into all devices. In this case, after performing the tape expansion step, the support table 10 supporting the semiconductor wafer 2 is retracted via the dicing tape 9, and the semiconductor wafer 2 is separated into individual devices 22 from the dicing tape 9 side by dividing means. A dividing step for complete division is performed. In the illustrated embodiment, this dividing step is performed using the dividing means 12 shown in FIG. The dividing means 12 shown in FIG. 14A includes a suction holding member 120 having an elongated rectangular holding surface 121. The length of the holding surface 121 constituting the suction holding member 120 in the longitudinal direction is slightly longer than the diameter of the semiconductor wafer 2. The holding surface 121 is formed with a V-shaped long groove 122 along the longitudinal direction. The inclined surfaces 123 and 124 forming the V-shaped long groove 122 are each provided with a plurality of suctions along the longitudinal direction. Holes 123a and 124a are formed. The plurality of suction holes 123a and 124a communicate with suction means (not shown).

In order to divide the semiconductor wafer 2 into individual devices 22 using the dividing means 12 shown in FIG. 14A, a V-shaped long groove 122 formed on the holding surface 121 constituting the suction holding member 120 is formed. While being positioned at a position corresponding to the street 21 formed on the semiconductor wafer 2, the holding surface 121 is brought into contact with the back surface (lower surface) of the dicing tape 9 attached to the semiconductor wafer 2 as shown in FIG. . Then, a suction means (not shown) is operated to apply a negative pressure to the dicing tape 9 attached to the semiconductor wafer 2 through the plurality of suction holes 123a and 124a. As a result, since the dicing tape 9 is sucked and the street 21 located between the slopes 123 and 124 is sucked downward, bending stress is generated along the street 21 and the strength of the semiconductor wafer 2 is lowered. It is reliably broken along the street 21 (division process). By performing this dividing step along all the streets 21 formed on the semiconductor wafer 2 or the streets 21 that are not broken, the semiconductor wafer 2 is surely divided into individual devices 22.
In the embodiment shown in FIGS. 14A and 14B, the angle between the inclined surfaces 123 and 124 formed on the holding surface 121 of the suction holding member 120 constituting the dividing means 12 is exaggerated. However, it is actually set to 179 to 178 degrees.

  If the above-described dividing step is performed, the dicing tape 9 is expanded and placed on and supported on the support table 10 (wafer re-supporting step), and the annular frame mounting step is performed.

2: Semiconductor wafer 21: Street 22: Device 210: Modified layer 3: Protection tape 4: Laser processing apparatus 41: Chuck table 42: Laser beam irradiation means 422: Condenser 5: Grinding apparatus 51: Chuck table 52: Grinding means 524: Grinding wheel 526: Grinding wheel 6: First suction holding pad 7: Second suction holding pad 8: Tape sticking device 9: Dicing tape 10: Support table 11: Ring frame 12: Dividing means

Next, a tape expansion process is performed in which the dicing tape 9 attached to the back surface of the semiconductor wafer 2 on which the protective member peeling process has been performed is expanded to widen the interval between the devices. That is, as shown in FIG. 11A, the dicing tape 9 (adhered to the back surface of the semiconductor wafer 2 divided into individual devices) placed on the support table 10 is expanded in all directions. As a result, an interval (s) is formed between the individual devices 22 attached to the dicing tape 9 as shown in FIG.

Claims (2)

A wafer processing method for dividing a wafer in which devices are formed in a plurality of regions partitioned by a street formed in a lattice shape on the surface, along the street,
A protective member attaching step for attaching a protective member to the surface of the wafer;
A modified layer forming step of irradiating a laser beam having a wavelength having transparency to the wafer from the back side of the wafer along the street, and forming a modified layer along the street inside the wafer;
The protective member side of the wafer is held by the holding means of the grinding device, and is ground by pressing the back surface of the wafer while rotating the grinding wheel to form the wafer with a predetermined thickness and on the street where the modified layer is formed. Grinding process to divide along the individual devices,
A wafer unloading step of sucking and holding the entire back surface of the wafer subjected to the grinding step with a first suction holding pad and unloading from the holding means of the grinding device;
The protection attached to the surface of the wafer on the second suction holding pad with the protective member attached to the surface of the wafer sucked and held on the first suction holding pad facing upward A wafer transfer step of sucking and holding the member side to separate the first suction holding pad from the wafer;
A dicing tape adhering step of adhering the adhesive surface of the dicing tape to the back surface of the wafer on which the protective member side is sucked and held by the second suction holding pad;
A wafer support step of supporting the wafer on which the dicing tape attaching step has been performed on a support table via the dicing tape and separating the second suction holding pad from the wafer;
A protective member peeling step for peeling off the protective member attached to the surface of the wafer on which the wafer supporting step has been performed;
A tape expansion step of expanding the interval between the devices by expanding the dicing tape attached to the wafer on which the protective member peeling step has been performed;
Attaching an annular frame having an opening having a size to accommodate the wafer subjected to the tape expansion process to the adhesive surface of the dicing tape, and attaching the wafer to the opening through the dicing tape Process,
A dicing tape cutting step for cutting the dicing tape corresponding to the annular frame,
A method for processing a wafer. After performing the tape expansion step, the dividing table for retracting the support table supporting the wafer via the dicing tape and completely dividing the wafer into individual devices by the dividing means from the dicing tape side;
A wafer re-supporting step of placing and supporting the dicing tape on the support table in an expanded state after performing the dividing step;
The wafer processing method according to claim 1, wherein the annular frame mounting step is performed after the wafer re-supporting step.

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