JP4741331B2 - Wafer processing method - Google Patents

Description

  The present invention relates to a wafer processing method for obtaining a plurality of devices by dividing a wafer such as a semiconductor wafer, and in particular, a wafer having a peripheral excess region around a device region where a plurality of devices are formed. The present invention relates to a processing method in which only the device is thinned and then divided into devices.

  A semiconductor chip of a device used for various electronic devices generally has a rectangular rectangular area defined by dividing lines called streets on the surface of a disk-shaped semiconductor wafer, and an electronic circuit is formed on the surface of these areas. Then, it is manufactured by a method in which the back surface is ground and thinned and divided along the street. By the way, downsizing and thinning of electronic devices in recent years are remarkable, and accordingly, a semiconductor chip is required to be thinner, which means that it is necessary to make the semiconductor wafer thinner than before.

  However, when the semiconductor wafer is thinned, the rigidity is lowered, so that there is a problem that handling in the subsequent process becomes difficult or breakage is likely to occur. Therefore, only the circular device region in which the semiconductor chip is formed is ground and thinned from the back side, and the above-mentioned problem due to thinning is formed by forming the peripheral outer peripheral region of the periphery as a relatively thick reinforcing portion. It has been done to prevent this from occurring. In this case, since the back side is ground, the thick reinforcing portion protrudes to the back side. Thus, the technique which makes only an outer peripheral part thickness is disclosed by patent document 1, for example.

JP-A-5-121384

  Such a semiconductor wafer is finally cut by a cutting device or the like and divided into semiconductor chips. As a cutting apparatus, there is a type in which a semiconductor wafer is adsorbed and held on a vacuum chuck type horizontal chuck table and cut by cutting a cutting blade from above, and the semiconductor wafer is usually attached to the back surface. It is supported by a frame mounted on the dicing tape, and held with the dicing tape side facing the chuck table.

  Here, if the semiconductor wafer is flat, the entire back surface thereof is in close contact with the chuck table, so that it is stably held. As described above, there is a thick reinforcing portion that protrudes to the back side of the outer peripheral portion. Then, stable holding is difficult. Therefore, change the chuck table to a shape that fits the back side of the concave semiconductor wafer, or grind the reinforcing part and finally process the entire semiconductor wafer into a flat plate shape. It has been carried out stably. However, these means are troublesome and reduce productivity.

  Therefore, the present invention improves the efficiency of the process of obtaining a plurality of devices by thinning only the device region surrounded by the outer peripheral surplus region, and dividing the device region in the same manner as usual. It is an object of the present invention to provide a method for processing a wafer that can be performed and the increase in cost can be suppressed.

The wafer processing method of the present invention is a wafer processing method having an outer peripheral surplus region around a device region in which a plurality of devices are formed, and the adhesive force is applied to the surfaces of the device region and the outer peripheral surplus region by ultraviolet irradiation. A protective tape attaching step for attaching a protective tape having a deteriorating property; and the protective tape side is held on the chuck table with the protective tape side facing the chuck table of the grinding device, and the back surface of the wafer exposed in this state is Grinding a portion corresponding to the device region and processing the wafer into a concave cross-section in which a thick reinforcing portion is formed in a portion corresponding to the outer peripheral surplus region, and the wafer subjected to the grinding step to the chuck table The wafer unloading process for unloading the wafer, and the protective tape side facing the chuck table of the cutting device so that the wafer is placed on the chuck table. Lifting, and a reinforcing portion cutting step of cutting the reinforcement portion by the cutting tool of the cutting device, with UV to reduce the adhesive strength of該貼adhesive portion is irradiated only to the attaching portion of the outer peripheral marginal area of the protective tape Then, by applying an external force to the reinforcing portion , the reinforcing portion is separated from the device region and the device region is left, and a device region remaining process in which the wafer is only the device region and a back surface of the wafer via a dicing tape And a dicing frame mounting step for mounting the dicing frame, and a dividing step for dividing the wafer supported by the dicing frame into devices.

  According to the present invention, in the grinding process, only the device region is ground and thinned from the back surface side, whereby the outer peripheral surplus region is divided into devices by obtaining a wafer formed in a relatively thick reinforcing portion. The handling and damage resistance of the wafer up to the dividing process are improved. In the dividing step, the wafer in which the reinforcing portion is separated and only the device region is divided, so that the dividing step into devices can be easily performed while holding the wafer on a normal chuck table.

In the process of leaving the wafer only in the device region in the present invention, first, the wafer is held on the chuck table and the reinforcing portion is cut. At this point, the reinforcing part is connected to the device region by the protective tape. Next, only the outer peripheral surplus area of the protective tape, that is, the part that is attached to the reinforcing part is irradiated with ultraviolet rays. As a result, the adhesive force of the protective tape with respect to the reinforcing portion is reduced. Therefore, by applying an external force to the reinforcing portion , the reinforcing portion can be separated from the protective tape and separated from the device region. Thereafter, the wafer having only the device region is supported by a dicing frame via a dicing tape, and the wafer is divided into a plurality of devices by a cutting device or the like. According to the present invention, the process from the removal of the reinforcing portion to the division into devices efficiently proceeds, and the division into devices is easy, so that an increase in cost can be suppressed.

  In the present invention, as the protective tape to be attached to the back surface of the wafer, a normal protective tape having no such characteristics can be used instead of the above-mentioned one having the characteristic that the adhesive strength is reduced by the ultraviolet irradiation. In that case, the wafer is held on the chuck table and the reinforcing portion is cut, and both are connected with the protective tape, and then the protective tape is cut to separate the reinforcing portion from the device region, thereby the device. Get an area-only wafer.

Specifically, it is a wafer processing method having an outer peripheral surplus area around a device area where a plurality of devices are formed, and a protective tape adhering step of adhering a protective tape to the surface of the device area and the outer peripheral surplus area And holding the wafer on the chuck table with the protective tape side facing the chuck table of the grinding device, grinding the portion corresponding to the device region on the back surface of the wafer exposed in this state, A grinding step for processing a concave section with a thick reinforcing portion formed in a portion corresponding to the outer peripheral surplus region, a wafer unloading step for unloading the wafer after the grinding step from the chuck table, and the protective tape side of the cutting device Reinforcing part cutting that holds the wafer on the chuck table facing the chuck table and cuts the reinforcing part with the cutting tool of the cutting device. A step, a boundary portion between the device region and the reinforcement portion of the protective tape was cut with a cutter, with the separation of the reinforcement portion from the device region thereby leaving the device region, device region remaining to the wafer device region only Process,
A dicing frame mounting step for mounting a dicing frame on a back surface of the wafer via a dicing tape and a dividing step for dividing the wafer supported by the dicing frame into devices are provided.

  According to the present invention, in obtaining a plurality of devices from a wafer having an outer peripheral surplus region around the device region, after thinning only the device region, the device region is divided to obtain a plurality of devices. In addition, the device can be divided as usual, and an increase in cost can be suppressed.

Hereinafter, a wafer processing method according to first to third embodiments of the present invention will be described with reference to the drawings.
[1] Processing Method of First Embodiment Reference numeral 1 in FIG. 1 denotes a disk-shaped semiconductor wafer (hereinafter abbreviated as a wafer) made of a silicon wafer or the like. The thickness of the wafer 1 before processing is, for example, about 600 μm, and a rectangular semiconductor chip (device) 3 is partitioned on the surface by lattice-like streets (division planned lines) 2. Electronic circuits are formed on the surfaces of these semiconductor chips 3. A region where the plurality of semiconductor chips 3 are formed is a substantially circular device region 5 concentric with the wafer 1, and an annular outer peripheral region 6 exists around the device region 5.

  In the present embodiment, a portion corresponding to the device region 5 on the back surface of the wafer 1 is ground to thin the portion to a required thickness, and the semiconductor chip 3 is obtained by dividing the semiconductor chip 3 individually from the thinned device region 5. Is the method. In the following description, the “front surface” of the wafer 1 is defined as the surface on the side where the electronic circuit is formed, and the “back surface” is defined as the surface on the side opposite to the surface where the electronic circuit is not formed.

(1) Protective tape sticking step As shown in FIG. 2, a circular protection having a characteristic that the adhesive force is reduced by ultraviolet irradiation on the entire surface of the wafer 1, that is, both the device region 5 and the outer peripheral surplus region 6. Tape 7 is attached. As the protective tape 7, for example, an ultraviolet curable type in which an acrylic adhesive having a thickness of about 5 to 20 μm is applied to one surface of a relatively flexible base material such as a polyolefin having a thickness of about 70 to 200 μm is suitable. The adhesive is attached to the surface of the wafer. For example, an adhesive strength before irradiation with ultraviolet rays of 2.06 N / 25 mm and an adhesive strength reduction property of about 0.05 N / 25 mm after ultraviolet irradiation are effective. The protective tape 7 protects the electronic circuit of the semiconductor chip.

(2) Grinding process The back surface side corresponding to the device region 5 of the wafer 1 having the protective tape 7 attached to the surface is ground, and the device region 5 has a necessary thickness (for example, about 200 to 100 μm, or about 50 μm). ). 3 and 4 show a grinding apparatus 10 used for this purpose. The grinding apparatus 10 includes a vacuum chuck type chuck table 11 that is rotationally driven, and a grinding unit 12. The chuck table 11 has a disk shape larger than the wafer 1, and adsorbs and holds the wafer 1 placed on the upper surface thereof by air suction. The chuck table 11 is rotated by a motor (not shown) around the center.

  In the grinding unit 12, when a spindle 14 incorporated in a cylindrical housing 13 is driven to rotate by a motor 15, a cup wheel 17 fixed to the tip of the spindle 14 via a flange 16 rotates, and the cup wheel 17 A number of grindstone segments 18 arranged and fixed in an annular shape over the entire circumference on the outer peripheral portion of the lower surface of the steel plate grind the workpiece. The outer diameter of the circular grinding locus of the grindstone segment 18 is approximately equal to the radius of the diameter of the device region 5 of the wafer 1.

  The chuck table 11 and the grinding unit 12 are offset with respect to the chuck table 11. Specifically, as shown in FIG. 4, the center portion of the blade thickness (the length in the radial direction) of the blade edge of the many grindstone segments 18 arranged in an annular shape at the innermost side of the chuck table 11 is the chuck. The relative position is set so as to be positioned on the vertical line L passing through the center of the table 11.

  The wafer 1 is held on the chuck table 11 with the protective tape 7 side facing the upper surface of the chuck table 11 and with the center aligned with the rotation center of the chuck table 11. Then, the grinding unit 12 is lowered while rotating the cup wheel 17, all the grindstone segments 18 are pressed against the exposed back surface of the wafer 1, and the chuck table 11 is rotated, thereby corresponding to the device region 5 on the back surface. The part to be ground is ground and thinned. As shown in FIG. 5, the wafer 1 has a cross section in which an annular reinforcing portion 8 is formed in the portion corresponding to the outer peripheral surplus region 6 around the device region 5 and the original thickness remains and protrudes to the back side. Processed into a concave shape.

  The wafer 1 that has undergone the above grinding process is transferred to the next wafer unloading process. Before that, the back surface is polished or etched, or a metal thin film is formed on the back surface by a technique such as vapor deposition or sputtering. There is something. Furthermore, the adhesive film at the time of using it, laminating | stacking the semiconductor chip 3 may be affixed on the back surface. In the specification of forming a metal thin film by vapor deposition or sputtering, the protective tape 7 having heat resistance is used so that it does not melt during the treatment.

(3) Wafer Unloading Step The wafer 1 having the device region 5 ground and thinned from the device region 5 is unloaded from the chuck table 11 of the grinding apparatus 10 and used in the next reinforcing portion cutting step. The cutting apparatus 20 shown in FIG.

(4) Reinforcing Section Cutting Step The cutting device 20 includes a vacuum chuck type chuck table 21 that is rotationally driven and a cylindrical cutting unit 22 as shown in FIG. The cutting unit 22 has a horizontal axis, and a cutting blade 23 that is rotationally driven by a motor (not shown) is coaxially attached to one end of the cutting unit 22.

  The cutting unit 22 is driven up and down so as to cut into the wafer 1 held on the chuck table 21. The wafer 1 is held on the chuck table 21 with the protective tape 7 side facing the upper surface of the chuck table 11 and with the center aligned with the rotation center of the chuck table 21. Then, while rotating the chuck table 21, the rotating cutting blade 23 is cut into the boundary portion between the device region 5 and the reinforcing portion 8, that is, the outer peripheral edge of the thinned device region 5.

  The cutting depth of the cutting blade 23 is equal to the thickness of the thinned device region 5 or slightly inserted into the protective tape 7. As the chuck table 21 rotates once, as shown in FIG. 7, a notch 9 is inserted between the reinforcing portion 8 and the device region 5, and both are separated, but are still connected by the protective tape 7.

(5) Device Region Remaining Step A step of separating the reinforcing portion 8 from the device region 5 and leaving the device region 5 is performed by the wafer processing apparatus 30 shown in FIGS. The wafer processing apparatus 30 includes a base 31 and a mounting table 32 installed on the base 31. The mounting table 32 has a disk-shaped turntable 34 that is rotationally driven attached to an upper part of a cylindrical fixed base 33. Around the mounting table 32, a plurality (four in the illustrated example) of arcuate pusher pads 36 that are driven up and down along the guide posts 35 erected on the base 31 are arranged at equal intervals along the circumferential direction. Is placed. Each pusher pad 36 moves up and down with the vertical positions aligned with each other.

  The outer diameter of the fixing table 33 and the turntable 34 of the mounting table 32 is the same and is equal to the diameter of the device region 5 of the wafer 1, and the wafer 1 is coaxial with the protective tape 7 side facing on the turntable 34. Placed on. The wafer 1 is conveyed to the mounting table 32 by a method such as clamping the reinforcing portion 8. In this mounted state, as shown in FIG. 9A, the lower surface of the wafer 1, that is, the surface covered with the protective tape 7, the device region 5 overlaps the upper surface of the turntable 34, and the reinforcing portion 8 is It protrudes from the turntable 34.

  Thus, the reinforcing portion 8 protrudes from the turntable 34, and the positional relationship and shape are set so that each pusher pad 36 contacts only the protruding reinforcing portion 8 when the pusher pad 36 is lowered from the position above the guide post 35. Has been. Further, an ultraviolet lamp 37 that irradiates the lower surface of the reinforcing portion 8 with ultraviolet rays is disposed on the base 31. The ultraviolet lamp 37 has an irradiation direction obliquely upward, and is provided so as to advance and retreat with respect to the fixed base 33 along a guide rail 38 installed on the base 31.

  In order to carry out the device region remaining step, all the pusher pads 36 of the wafer processing apparatus 30 are raised, and then the wafer 1 is coaxially placed on the turntable 34 of the mounting table 32 with the protective tape 7 side facing. To place. Next, as shown in FIG. 10, the turntable 34 is rotated at least once while irradiating the lower surface of the reinforcing portion 8 with ultraviolet rays from the ultraviolet lamp 37 moved to the placement table 32 side. Thereby, ultraviolet rays are irradiated over the entire annular portion of the protective tape 7 attached to the reinforcing portion 8, the adhesive strength of the attached portion is reduced, and the protective tape 7 is easily peeled off from the reinforcing portion 8. When this operation is finished, the ultraviolet lamp 37 is retracted and the turntable 34 is stopped.

  In this embodiment, the ultraviolet light is irradiated to the entire circumference of the reinforcing portion 8 by the rotation of one ultraviolet lamp 37 and the turntable 34, but the wafer 1 is fixedly placed on the placement table 32. The ultraviolet lamp 37 may be formed in an annular shape over the entire circumference, or a number of ultraviolet lamps 37 may be arranged in an annular shape so that the ultraviolet light can be irradiated over the entire circumference of the reinforcing portion 8.

  Next, as shown in FIGS. 9A to 9B, the pusher pad 36 that has been waiting above the reinforcing portion 8 is lowered. Then, as shown in FIG. 9B, the reinforcing portion 8 in the state supported by the protective tape 7 is pushed down by the pusher pad 36 due to the decrease in the adhesive force of the protective tape 7, and the protective tape 7 And fall on the base 31. That is, the reinforcing portion 8 is separated from the device region 5, and only the device region 5 remains on the mounting table 32. In addition, the reinforcement part 8 which fell on the base 31 is collect | recovered suitably as an end material.

(6) Dicing frame mounting step In this step, as shown in FIGS. 11 to 12, dicing is performed on the upper surface, that is, the back surface of the wafer 1 only in the device region 5 left on the mounting table 32 of the wafer processing apparatus 30. An annular dicing frame 42 is attached via the tape 41. The dicing tape 41 is made of, for example, polyvinyl chloride having a thickness of about 100 μm as a base material and having an acrylic resin-based adhesive applied to a thickness of about 5 μm on one side. The dicing tape 41 is circular with a diameter larger than that of the wafer 1, and an annular dicing frame 42 is concentrically attached to the adhesive side of the outer peripheral portion thereof. The inner diameter of the dicing frame 42 is larger than the diameter of the wafer 1 having only the device region 5.

  In order to mount the dicing frame 42 on the wafer 1, as shown in FIG. 11, first, the dicing frame 41 of the dicing tape 41 is attached to the suction pad 52 of the vacuum chuck type chuck portion 51 provided at the tip of the transfer arm 50. Adsorbs and holds the non-adhesive side to which 42 is not attached. Then, the dicing tape 41 and the dicing frame 42 are conveyed by the conveying arm 50 to the position immediately above the wafer 1 placed on the placement table 32 of the wafer processing apparatus 30 and further lowered so that the dicing frame 42 is moved to the wafer 1. The dicing tape 41 is attached to the upper surface (back surface) of the wafer 1 so as to be concentric with the wafer 1.

  Next, as shown in FIG. 12, the dicing tape 41 is strongly pressed against the entire upper surface of the wafer 1 by the pressing roller 45 having a length exceeding the diameter of the wafer 1, thereby strengthening the attached state. In this step, the pusher pad 36 is lowered to a position where it does not interfere with the dicing frame 42.

(7) Dividing Step On the mounting table 32, the wafer 1 with the protective tape 7 on the lower surface (front surface) and the dicing tape 41 on the upper surface (back surface) is turned over by an appropriate method, and the wafer 1 is removed. 13, the dicing frame 42 is sucked and held on the suction pad 52 of the chuck portion 51 in the transport arm 50 and transported onto the vacuum chuck type chuck table 61, and the chuck table as illustrated in FIG. 14. 61 is mounted. The wafer 1 on the chuck table 61 is such that the surface on which the protective tape 7 is applied is on the upper side and the back surface on which the dicing tape 41 is applied on the lower side, and this wafer 1 is adsorbed and held on the chuck table 61. .

  Next, as shown in FIGS. 14A to 14B, the strong adhesive tape 63 wound around the rotating roller 62 is pressed against the outer peripheral portion of the protective tape 7 and rolled to the inner peripheral side, thereby protecting the protective tape. 7 is wound around the strong adhesive tape 63 and peeled off from the wafer 1. In addition, when the adhesive force of the protective tape 7 is reduced in advance by irradiating the protective tape 7 with ultraviolet rays during or after the conveyance to the chuck table 61, the protective tape 7 can be easily peeled off. It is desirable to adopt this method.

  The wafer 1 from which the protective tape 7 has been peeled off in this way is transferred to an apparatus for dividing the semiconductor chip 3, and the street 2 is cut by the apparatus to be divided into the semiconductor chips 3. As the dividing device, the cutting device 20 shown in FIG. 6 may be used, and the wafer 1 held on the chuck table 21 may be cut by the cutting blade 23 and divided, or a device dedicated to the division is used. Of course.

According to the present embodiment, in the grinding process, only the device region 5 is ground and thinned from the back surface side, thereby obtaining the wafer 1 in which the outer peripheral surplus region 6 is formed in the relatively thick reinforcing portion 8. The handling property and damage resistance of the wafer 1 up to the dividing step for dividing the semiconductor chip 3 are improved. In the dividing step, the wafer 1 separated from the reinforcing portion 8 and having only the device region 5 is divided. Therefore, an operation of holding the wafer 1 on a normal flat chuck table and dividing it into the semiconductor chips 3 is performed. It can be done easily. Since the process from the removal of the reinforcing portion 8 to the division into the semiconductor chips 3 proceeds in series, it is efficient, and the division into the semiconductor chips 3 can also be performed as described above. The rise is also suppressed.
Subsequently, second and third embodiments of the present invention in which the content of the process is changed based on the first embodiment will be described below.

[2] Processing Method of Second Embodiment The processing method of the second embodiment is exactly the same up to the reinforcing portion cutting step of the first embodiment, and the following device is used instead of the device region remaining step. The region remaining process is performed.

  For this, a protective tape cutting device 70 shown in FIG. 15 is used. The protective tape cutting device 70 has a mounting table 72 similar to the mounting table 32 of the wafer processing device 30. That is, the mounting table 72 has a configuration in which a turntable 74 is attached above a cylindrical fixed base 73, and a cutter mechanism 75 is provided on the side surface of the fixed base 33.

  The cutter mechanism 75 has a cutter holder 77 that advances and retreats upward by a cylinder 76 fixed to the peripheral surface of the fixing base 73, and a blade portion 78 that extends upward is held by the cutter holder 77. The distance from the blade portion 78 to the rotation center of the turntable 74 is set to a distance equal to the diameter of the device region 5 of the wafer 1.

  In the device region remaining process of the second embodiment, first, the wafer 1 that has undergone the above-described reinforcing portion cutting process is placed on the turntable 74 with the protective tape 7 side facing the turntable 34 and concentrically. . In this mounted state, only the reinforcing portion 8 of the wafer 1 protrudes outside the turntable 34. Then, the blade portion 78 is raised together with the cutter holder 77 while rotating the turntable 34. The blade portion 78 penetrates the protective tape 7 and enters the notch 9 between the separated device region 5 and the reinforcing portion 8, and since the wafer 1 is rotated by the turntable 74 in this state, the wafer 1 Is rotated once or more, the boundary portion between the device region 5 and the reinforcing portion 8 of the protective tape 7 is cut into an annular shape. As a result, the reinforcing portion 8 connected to the device region 5 by the protective tape 7 is separated from the device region 5 and falls, and only the device region 5 remains on the turntable 34.

It is a whole perspective view of the wafer divided | segmented into a semiconductor chip in embodiment of this invention, and an enlarged part shows a semiconductor chip. It is a perspective view of the wafer by which the protective tape was stuck on the surface at the protective tape sticking process of a 1st embodiment. It is a perspective view of a grinding device used in a grinding process. It is a side view of the grinding device. It is sectional drawing of the wafer after a grinding process. It is a perspective view of the cutting device used at a reinforcement part cutting process. It is sectional drawing which shows the wafer from which the reinforcement part was cut | disconnected. It is a perspective view of a wafer processing apparatus used in a device region remaining process. It is a side view which shows the isolation | separation operation | movement of the reinforcement part in a device area | region residual process by (a)-(b). It is the (a) perspective view and the (b) side view which show the state of the ultraviolet irradiation in a device area | region residual process. It is a side view which shows the state which sets a wafer to a wafer processing apparatus by a dicing frame mounting process. It is a side view which shows the state which attaches a dicing tape firmly to a wafer with a pressing roller at a dicing frame mounting process. It is a side view which shows the state which mounts a wafer on the chuck table for peeling a protective tape at a division | segmentation process. It is a side view which shows the state which has peeled the protective tape at the division | segmentation process by (a)-(b). It is the (a) perspective view and (b) side view of the protective tape cutting device used by 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wafer, 3 ... Semiconductor chip (device), 5 ... Device area | region,
6 ... surplus outer peripheral area, 7 ... protective tape, 8 ... reinforcing part, 10 ... grinding device,
11 ... chuck table of grinding device, 20 ... cutting device,
21 ... Chuck table of the cutting device, 23 ... Cutting blade (cutting tool),
41 ... Dicing tape, 42 ... Dicing frame, 75 ... Cutter mechanism.

Claims (2)

A method of processing a wafer having an outer peripheral surplus region around a device region where a plurality of devices are formed,
A protective tape attaching step of attaching a protective tape having a characteristic that the adhesive force is reduced by ultraviolet irradiation to the surface of the device region and the outer peripheral surplus region,
Holding the wafer on the chuck table with the protective tape side facing the chuck table of the grinding device, grinding the portion corresponding to the device region on the back surface of the wafer exposed in this state, A grinding step for processing into a concave cross section in which a thick reinforcing portion is formed in a portion corresponding to the outer peripheral surplus region;
A wafer unloading step of unloading the wafer after the grinding step from the chuck table;
A reinforcing portion cutting step of holding the wafer on the chuck table with the protective tape facing the chuck table of the cutting device and cutting the reinforcing portion with a cutting tool of the cutting device;
After irradiating only the adhesion part of the protective tape to the outer peripheral surplus area with ultraviolet rays to reduce the adhesive force of the adhesion part , the reinforcement part is removed from the device area by applying an external force to the reinforcement part. A device region remaining step of separating and leaving the device region, wherein the wafer is only the device region; and
A dicing frame mounting step of mounting a dicing frame on the back surface of the wafer via a dicing tape;
And a dividing step of dividing the wafer supported by the dicing frame into devices. A method of processing a wafer having an outer peripheral surplus region around a device region where a plurality of devices are formed,
A protective tape attaching step of attaching a protective tape to the surface of the device region and the outer peripheral surplus region;
Holding the wafer on the chuck table with the protective tape side facing the chuck table of the grinding device, grinding the portion corresponding to the device region on the back surface of the wafer exposed in this state, A grinding step for processing into a concave cross section in which a thick reinforcing portion is formed in a portion corresponding to the outer peripheral surplus region;
A wafer unloading step of unloading the wafer after the grinding step from the chuck table;
A reinforcing portion cutting step of holding the wafer on the chuck table with the protective tape facing the chuck table of the cutting device and cutting the reinforcing portion with a cutting tool of the cutting device;
A device in which a boundary portion between the device region and the reinforcing portion in the protective tape is cut with a cutter so that the reinforcing portion is separated from the device region and the device region remains, and the wafer is only the device region. Region remaining process;
A dicing frame mounting step of mounting a dicing frame on the back surface of the wafer via a dicing tape;
And a dividing step of dividing the wafer supported by the dicing frame into devices.

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