JP2017108001A - Processing method of wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing method of a wafer capable of removing the outer peripheral excessive region of the wafer at a low cost.SOLUTION: A processing method of a wafer includes a frame unit formation step of pasting a first UV-curable adhesive tape (21) to the surface (11a) side of a wafer (11), and mounting a first annular frame (23) on the outer peripheral part of the first adhesive tape, a division step of dividing the wafer into a device region (13) and an outer peripheral excessive region (15), a UV ray irradiation step of lowering the adhesive force of a region of the first adhesive tape corresponding to the device region, by irradiating a UV ray (UV), a sticking step of sticking a second adhesive tape (31), having a second annular frame (33) mounted on the outer periphery, to the back (11b) side of the wafer excepting the outer peripheral excessive region, and an exfoliation step of exfoliating the device region from the first adhesive tape, by widening the interval of the first and second annular frames.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a method for processing a wafer having a thin central device region.

  In the process of manufacturing a single-function device chip called discrete, for example, a metal film is formed on the back surface side of a semiconductor wafer thinned by a method such as grinding. However, a thinned semiconductor wafer tends to warp, and it is not easy to form a homogeneous metal film on the back side of the semiconductor wafer.

  Therefore, a semiconductor wafer processing method has been proposed in which only the central device region is ground from the back side to maintain the thickness of the outer peripheral surplus region (see, for example, Patent Document 1). According to this processing method, the warpage of the semiconductor wafer can be suppressed by the rigidity of the outer peripheral surplus region. The outer peripheral surplus area is removed by a removal device or the like before dividing into device chips (see, for example, Patent Document 2).

JP 2007-19461 A JP 2011-61137 A

  However, if the above-described removing apparatus is introduced to remove the outer peripheral surplus region, it becomes difficult to keep the manufacturing cost of the device chip low. The present invention has been made in view of such a problem, and an object of the present invention is to provide a wafer processing method capable of removing the excess peripheral area of the wafer at a low cost.

  According to one aspect of the present invention, a lattice-shaped street is divided into a plurality of regions on the front side, a device region in which a device is formed in each region, and an outer peripheral surplus region surrounding the device region. A method of processing a wafer having a recess formed by thinning the device region from the back side, wherein the ultraviolet curable first adhesive whose adhesive strength is reduced by irradiation of ultraviolet rays is applied to the front side of the wafer. A frame unit forming step of attaching a tape and mounting a first annular frame on the outer peripheral portion of the first adhesive tape; and after performing the frame unit forming step, the wafer is attached to the device region with a laser beam or a cutting blade And dividing the wafer into the device region and the outer peripheral surplus region, and the frame unit forming step. After carrying out, the ultraviolet rays that irradiate the areas other than the area corresponding to the outer peripheral surplus area of the first adhesive tape to reduce the adhesive strength of the area corresponding to the device area of the first adhesive tape. After performing the irradiation step, the ultraviolet irradiation step, and the dividing step, a second adhesive tape having a second annular frame attached to the outer peripheral portion is attached to the back side of the wafer excluding the outer peripheral region. Then, after carrying out the adhering step to make the first adhesive tape and the second adhesive tape adhered to the front surface side and the back surface side of the device region, respectively, By widening the interval between the first annular frame and the second annular frame, the device region is peeled off from the first adhesive tape while leaving the outer peripheral surplus region on the first adhesive tape. The second ring A peeling step of supporting said device region, the processing method of the wafer, characterized in that it comprises a is provided to the frame.

  In the wafer processing method according to one aspect of the present invention, the wafer having the first adhesive tape attached to the front side is divided into a device area and an outer peripheral surplus area, corresponding to the device area of the first adhesive tape. Since the second adhesive tape is affixed to the back side of the device area after the adhesive strength of the area to be reduced is reduced, it is attached to the first annular frame and the second adhesive tape attached to the first adhesive tape. In addition, by widening the distance from the second annular frame, the device region can be peeled from the first adhesive tape while leaving the outer peripheral surplus region on the first adhesive tape.

  That is, in the wafer processing method according to one aspect of the present invention, it is possible to easily remove the outer peripheral surplus region without introducing a removing device. That is, the outer peripheral surplus area of the wafer can be removed at a low cost. Further, in the wafer processing method according to one aspect of the present invention, since the surface side of the device region peeled off from the first adhesive tape is exposed, the device region can be easily processed later from the surface side.

It is a perspective view which shows the example of a structure of a wafer typically. It is a perspective view which shows a frame unit formation step typically. It is a partial cross section side view showing a division step typically. 4A is a partial cross-sectional side view schematically showing the ultraviolet irradiation step, and FIG. 4B is a plan view schematically showing the support plate. It is a partial cross section side view which shows a sticking step typically. It is a partial cross section side view which shows a peeling step typically. It is a partial cross section side view showing typically a device field processing step. It is a partial cross section side view which shows typically the division | segmentation step which concerns on a modification. It is a top view which shows typically the ultraviolet irradiation step which concerns on a modification.

  An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. The wafer processing method according to the present embodiment includes a frame unit forming step (see FIG. 2), a dividing step (see FIG. 3), an ultraviolet irradiation step (see FIGS. 4A and 4B), and an attaching step. (See FIG. 5), and a peeling step (see FIG. 6).

  In the frame unit forming step, an ultraviolet curable first adhesive tape is affixed to the front side of the wafer, and a first annular frame is attached to the outer peripheral portion of the adhesive tape. In the dividing step, the wafer is divided into a device area and an outer peripheral surplus area. In the ultraviolet irradiation step, the first adhesive tape is irradiated with ultraviolet rays to reduce the adhesive strength of the region corresponding to the device region.

  In the attaching step, the second adhesive tape having the second annular frame attached to the outer peripheral portion is attached to the back side of the device region. In the peeling step, the distance (distance) between the two annular frames is widened, and the device area is peeled off from the first adhesive tape while leaving the outer peripheral surplus area on the first adhesive tape. Hereinafter, the method for dividing the workpiece according to the present embodiment will be described in detail.

  FIG. 1 is a perspective view schematically showing a wafer 11 processed in this embodiment. As shown in FIG. 1, the wafer 11 is a circular substrate made of, for example, a material such as a semiconductor or ceramics, and is divided into a central device region 13 and an outer peripheral surplus region 15 surrounding the device region 13.

  The surface 11a side of the device region 13 is further divided into a plurality of regions by division lines (streets) arranged in a lattice pattern, and devices 17 such as transistors, diodes, and capacitors are formed in each region. Yes. The device 17 may be an integrated circuit called IC, LSI or the like.

  On the back surface 11b side of the device region 13, a recess 11c is provided. The recess 11c is formed, for example, by thinning the device region 13 from the back surface 11b side by a method such as grinding. On the other hand, the thickness of the outer peripheral surplus region 15 is maintained. The curvature of the wafer 11 can be suppressed by the rigidity of the outer peripheral surplus region 15.

  In the wafer processing method according to the present embodiment, first, an ultraviolet curable first adhesive tape is attached to the front surface 11a side of the wafer 11, and a first annular frame is attached to the outer periphery of the first adhesive tape. Then, a frame unit forming step for forming a frame unit in which the wafer 11 is supported by the first annular frame is performed.

  FIG. 2 is a perspective view schematically showing the frame unit forming step. In the frame unit forming step, for example, the first adhesive tape 21 is attached to the front surface 11 a side of the wafer 11. The 1st adhesive tape 21 contains the film-form base material and the adhesive layer provided in the surface of the one side of a base material.

  For the adhesive layer of the first adhesive tape 21, a resin or the like that is cured by ultraviolet rays is used. Therefore, the adhesive force of the first adhesive tape 21 to the wafer 11 can be reduced by irradiating the ultraviolet ray to cure the adhesive layer. After the first adhesive tape 21 is attached to the surface 11 a side of the wafer 11, the first annular frame 23 surrounding the wafer 11 is attached to the first adhesive tape 21.

  Thereafter, by cutting the first adhesive tape 21 in accordance with the shape of the first annular frame 23, the frame unit 25 in which the first annular frame 23 is mounted on the outer peripheral portion of the first adhesive tape 21 is completed. . In the frame unit 25, the wafer 11 is supported by the first annular frame 23 via the first adhesive tape 21.

  In the present embodiment, the first adhesive tape 21 is attached to the front surface 11a side of the wafer 11, and then the first annular frame 23 is attached to the first adhesive tape 21. It is also possible to attach the surface 11 a side of the wafer 11 to the first adhesive tape 21 after attaching the annular frame 23 to the first adhesive tape 21. The timing for cutting the first adhesive tape 21 may be arbitrary.

  After the frame unit forming step, a dividing step for dividing the wafer 11 into the device region 13 and the outer peripheral surplus region 15 is performed. In the present embodiment, a division step for dividing the wafer 11 into the device region 13 and the outer peripheral surplus region 15 using a laser beam will be described. As will be described later, the wafer 11 is separated from the device region 13 using a cutting blade. You may divide | segment into the outer periphery surplus area | region 15. FIG.

  FIG. 3 is a partial sectional side view schematically showing the dividing step. A division | segmentation step is implemented using the laser processing apparatus 2 shown in FIG. 3, for example. The laser processing apparatus 2 includes a holding table 4 for holding the wafer 11. The holding table 4 is connected to a rotation drive source (not shown) including a motor and the like, and rotates around a rotation axis substantially parallel to the vertical direction. Further, a moving mechanism (not shown) is provided below the holding table 4, and the holding table 4 moves in the horizontal direction by this moving mechanism.

  The upper surface (front surface) of the holding table 4 is a holding surface 4 a that sucks and holds the wafer 11 through the first adhesive tape 21 described above. The holding surface 4 a is connected to a suction source (not shown) through a suction path (not shown) formed inside the holding table 4. A plurality of clamps 6 for fixing the first annular frame 23 are provided around the holding table 4.

  A laser processing unit 8 is disposed above the holding table 4. The laser processing unit 8 focuses the laser beam L pulse-oscillated by a laser oscillator (not shown) on the wafer 11 on the holding table 4. For example, the laser oscillator is configured to be able to oscillate a laser beam L having a wavelength that is easily absorbed by the wafer 11 (wavelength having absorption).

  In the dividing step, first, the first adhesive tape 21 attached to the wafer 11 is brought into contact with the holding surface 4 a of the holding table 4, and the first annular frame 23 is fixed by the clamp 6. If the negative pressure of the suction source is applied in this state, the wafer 11 is held on the holding table 4 with the back surface 11b side exposed upward.

  Next, the holding table 4 is moved to position the laser processing unit 8 in an area corresponding to the boundary between the device area 13 and the outer peripheral surplus area 15. Then, the laser beam L is emitted from the laser processing unit 8 toward the back surface 11 b of the wafer 11 while rotating the holding table 4.

  Thereby, the region corresponding to the boundary between the device region 13 and the outer peripheral surplus region 15 is ablated with the laser beam L, and the wafer 11 can be divided into the device region 13 and the outer peripheral surplus region 15. In this embodiment, the wafer 11 is divided by ablation processing using the laser beam L. However, the boundary portion is modified by a laser beam having a wavelength that is difficult to be absorbed by the wafer 11 (wavelength having transparency), and the wafer 11 is divided. You can also

  After the dividing step, an ultraviolet irradiation step for irradiating the first adhesive tape 21 with ultraviolet rays to reduce the adhesive strength of the region corresponding to the device region 13 is performed. FIG. 4A is a partial cross-sectional side view schematically showing the ultraviolet irradiation step. The ultraviolet irradiation step is performed using, for example, an ultraviolet irradiation device 12 shown in FIG.

  As illustrated in FIG. 4A, the ultraviolet irradiation device 12 includes a box-shaped housing 14 and a support plate 16 that covers the upper portion of the housing 14. The housing 14 includes a bottom plate portion 14a that is rectangular in plan view and a side plate portion 14b that surrounds the periphery of the bottom plate portion 14a. A plurality of light sources 18 that emit ultraviolet rays UV are disposed above the bottom plate portion 14a.

  FIG. 4B is a plan view schematically showing the support plate 16. The support plate 16 includes a light shielding portion 16 a that overlaps an area corresponding to the outer peripheral surplus region 15 of the wafer 11, and a transparent portion 16 b that overlaps an area corresponding to the device region 13 of the wafer 11. The light shielding portion 16a is formed of, for example, a material that blocks ultraviolet UV emitted from the light source 18, and the transparent portion 16b is formed of, for example, a material that transmits ultraviolet UV emitted from the light source 18. The transparent portion 16b may be a through-hole formed in the support plate 16.

  In the ultraviolet irradiation step, the frame unit 25 is placed on the upper surface of the support plate 16 so that the back surface 11b side of the workpiece 11 is exposed upward, and the ultraviolet ray UV is emitted from the light source 18 with the device region 13 positioned at the transparent portion 16b. Radiate. Thereby, the area | region except the area | region corresponding to the outer periphery surplus area | region 15 of the 1st adhesive tape 21 is irradiated with ultraviolet-ray UV, and the adhesive force of the area | region corresponding to the device area | region 13 of the 1st adhesive tape 21 is reduced. Can do.

  As shown in FIG. 4A, a part of the side plate portion 14 b extends to above the support plate 16. By abutting the first annular frame 23 against a part of the side plate portion 14b, the position of the device region 13 can be aligned with the transparent portion 16b. In the present embodiment, the ultraviolet irradiation step is performed after the dividing step, but the dividing step may be performed after the ultraviolet irradiation step.

  After the dividing step and the ultraviolet irradiation step, an adhering step of adhering the second adhesive tape having the second annular frame attached to the outer peripheral portion to the back surface 11b side of the device region 13 is performed. FIG. 5 is a partial cross-sectional side view schematically showing the attaching step. The sticking step is performed using, for example, a sticking device 22 shown in FIG.

  As shown in FIG. 5, the sticking device 22 includes a holding table 24 for holding the wafer 11. The holding table 24 is connected to a rotation drive source (not shown) including a motor and the like, and rotates around a rotation axis substantially parallel to the vertical direction. Further, a moving mechanism (not shown) is provided below the holding table 24, and the holding table 24 moves in the horizontal direction by this moving mechanism.

  The upper surface (front surface) of the holding table 24 is a holding surface 24 a that sucks and holds the wafer 11 through the first adhesive tape 21 described above. The holding surface 24 a is connected to a suction source (not shown) through a suction path (not shown) formed inside the holding table 24.

  A plurality of clamps 26 for fixing the first annular frame 23 are provided around the holding table 24. A pressing roller 28 is disposed above the holding table 24. For example, the roller 28 is supported by an elevating mechanism and moves in the vertical direction.

  In the attaching step, first, the first adhesive tape 21 attached to the wafer 11 is brought into contact with the holding surface 24 a of the holding table 24, and the first annular frame 23 is fixed by the clamp 26. If the negative pressure of the suction source is applied in this state, the wafer 11 is held on the holding table 24 with the back surface 11b side exposed upward.

  Next, the holding table 24 is moved to position the roller 28 above the device region 13. Also, a second adhesive tape 31 is prepared and stacked on the back surface 11 b side of the wafer 11. Here, a second annular frame 33 is mounted in advance on the outer peripheral portion of the second adhesive tape 31.

  As the 2nd adhesive tape 31 and the 2nd annular frame 33, the same thing as the 1st adhesive tape 21 and the 1st annular frame 23 can be used, for example. However, as the second pressure-sensitive adhesive tape 31, a pressure-sensitive adhesive tape that is not an ultraviolet curable type can also be used.

  In this state, the holding table 24 is rotated while lowering the roller 28 and applying pressure to the second adhesive tape 31 from above. Thereby, the 2nd adhesive tape 31 can be affixed on the back surface 11b side of the wafer 11 except the outer periphery excess area | region 15. FIG. That is, the first adhesive tape 21 and the second adhesive tape 31 are attached to the front surface 11a side and the back surface 11b side of the device region 13, respectively.

  In this attaching step, the second annular frame 33 is separated from the first annular frame 23 so that the second adhesive tape 31 does not contact the first adhesive tape 21 and the outer peripheral surplus region 15. Is desirable. For example, the distance between the first annular frame 23 and the second annular frame 33 can be easily secured by using a table (not shown) or the like that supports the second annular frame 33. Of course, the second annular frame 33 may be supported by an operator or the like.

  After the attaching step, the space (distance) between the first annular frame 23 and the second annular frame 33 is widened, and the device region 13 is moved to the first adhesive tape 21 while leaving the outer peripheral surplus region 15 on the first adhesive tape 21. A peeling step for peeling from the first adhesive tape 21 is performed. FIG. 6 is a partial cross-sectional side view schematically showing the peeling step.

  In the peeling step, first, the holding table 24 and the roller 28 are relatively moved to retract the roller 28 from above the holding table 24. Next, as shown in FIG. 6, the second annular frame 33 is pulled upward to widen the distance between the first annular frame 23 and the second annular frame 33.

  The adhesive strength of the area | region corresponding to the device area | region 13 of the 1st adhesive tape 21 is falling by the ultraviolet irradiation step mentioned above. Therefore, by widening the distance between the first annular frame 23 and the second annular frame 33, the device region 13 can be peeled from the first adhesive tape 21 and moved to the second adhesive tape 31 side. . That is, the device region 13 is supported by the second annular frame 33.

  In addition, the adhesive force of the area | region corresponding to the outer periphery surplus area | region 15 of the 1st adhesive tape 21 is maintained, and the 2nd adhesive tape 31 is hardly contacting the back surface 11b side of the outer periphery surplus area | region 15. . Therefore, the outer periphery surplus area | region 15 remains in the 1st adhesive tape 21 side in the state affixed on the 1st adhesive tape 21. FIG.

  After the peeling step, a device region processing step for processing the device region 13 or the like can be performed. FIG. 7 is a partial cross-sectional side view schematically showing a device region processing step. In addition, although the example which cuts the device area | region 13 is demonstrated here, there is no restriction | limiting in the content etc. of a device area | region process step.

  The device region processing step is performed using, for example, a cutting device 32 shown in FIG. The cutting device 32 includes a holding table 34 for holding the device region 13. The holding table 34 is connected to a rotation drive source (not shown) including a motor and the like, and rotates around a rotation axis substantially parallel to the vertical direction. A moving mechanism (not shown) is provided below the holding table 34, and the holding table 34 moves in the horizontal direction by this moving mechanism.

  The upper surface (front surface) of the holding table 34 is a holding surface 34 a that sucks and holds the device region 13 through the second adhesive tape 31. The holding surface 34 a is connected to a suction source (not shown) through a suction path (not shown) formed inside the holding table 34. A plurality of clamps 36 for fixing the second annular frame 33 are provided around the holding table 34.

  A cutting unit 38 for cutting the device region 13 is disposed above the holding table 34. The cutting unit 38 includes a spindle housing (not shown) supported by an elevating mechanism (not shown). A spindle 40 connected to a rotation drive source (not shown) including a motor and the like is accommodated in the spindle housing.

  The spindle 40 rotates around a rotation axis substantially parallel to the horizontal direction by a rotational force transmitted from a rotational drive source, and moves up and down together with the spindle housing by an elevating mechanism. An annular cutting blade 42 is attached to one end of the spindle 40 exposed to the outside of the spindle housing.

  In the device area processing step, first, the second adhesive tape 31 attached to the device area 13 is brought into contact with the holding surface 34 a of the holding table 34, and the second annular frame 33 is fixed by the clamp 36. If the negative pressure of the suction source is applied in this state, the device region 13 is held on the holding table 34 with the surface 11a side exposed upward.

  After the device area 13 is held by the holding table 34, the holding table 34 and the cutting blade 42 are relatively moved and rotated so that they are on an extension line of the planned division line set in the first direction of the device area 13. The cutting blade 42 is aligned with the above. Next, the cutting blade 42 is lowered to a height that reaches the second adhesive tape 31.

  Thereafter, the cutting blade 42 is rotated, and the holding table 34 is moved in a direction (first direction) parallel to the target division line. Thereby, the cutting blade 42 is cut from the surface 11a side, and the device region 13 can be divided along the target division line.

  After dividing the device region 13 along the target division line, the holding table 34 and the cutting blade 42 are relatively moved so that the cutting blade 42 is aligned with the extension of the adjacent division line. Then, the cutting blade 42 is lowered to a height that reaches the second adhesive tape 31.

  Thereafter, the cutting blade 42 is rotated, and the holding table 34 is moved in a direction (first direction) parallel to the planned division line. Thereby, the cutting blade 42 is cut from the surface 11a side, and the device region 13 can be divided along the division line.

  After the above procedure is repeated and the device region 13 is divided along all the division lines extending in the first direction, the holding table 34 and the cutting blade 42 are relatively moved and rotated, so that the first The cutting blade 42 is aligned with the extension line of the planned division line set in the second direction intersecting the direction.

  Then, the device region 13 is cut by the same procedure. When the device region 13 is divided along all the planned division lines extending in the second direction, the device region processing step ends.

  As described above, in the wafer processing method according to the present embodiment, the wafer 11 having the first adhesive tape 21 attached to the surface 11a side is divided into the device region 13 and the outer peripheral surplus region 15, and this first Since the second adhesive tape 31 is affixed to the back surface 11b side of the device region 13 after the adhesive strength of the region corresponding to the device region 13 of the adhesive tape 21 is reduced, the second adhesive tape 31 is attached to the first adhesive tape 21. By expanding the distance between the first annular frame 23 and the second annular frame 33 attached to the second adhesive tape 31, the device region 13 is left with the outer peripheral surplus region 15 remaining on the first adhesive tape 21. It can be peeled from the first adhesive tape 21.

  That is, in the wafer processing method according to this embodiment, the outer peripheral surplus region 15 can be easily removed without introducing a removing device. That is, the outer peripheral surplus area 15 of the wafer 11 can be removed at a low cost. Further, in the wafer processing method according to the present embodiment, the surface 11a side of the device region 13 peeled from the first adhesive tape 21 is exposed, so that the device region can be easily processed later from the surface 11a side, and the device region Alignment and the like when processing are facilitated.

  In addition, this invention is not limited to description of the said embodiment, A various change can be implemented. FIG. 8 is a partial cross-sectional side view schematically showing a dividing step according to a modification. The dividing step according to the modified example is performed using, for example, the cutting device 32 described above.

  Specifically, first, the first adhesive tape 21 attached to the wafer 11 is brought into contact with the holding surface 34 a of the holding table 34, and the first annular frame 23 is fixed by the clamp 36. If the negative pressure of the suction source is applied in this state, the wafer 11 is held on the holding table 34 with the back surface 11b side exposed upward.

  Next, the holding table 34 is moved, and the cutting blade 42 of the cutting unit 38 is positioned in an area corresponding to the boundary between the device area 13 and the outer peripheral surplus area 15. Then, the cutting unit 38 is lowered while rotating the cutting blade 42 and the holding table 4, and the cutting blade 42 is cut from the back surface 11 b side of the wafer 11. As a result, a region corresponding to the boundary between the device region 13 and the outer peripheral surplus region 15 can be cut to divide the wafer 11 into the device region 13 and the outer peripheral surplus region 15.

  FIG. 9 is a plan view schematically showing the ultraviolet irradiation step according to the modification. As shown in FIG. 9, in the ultraviolet irradiation step according to the modified example, the region corresponding to the device region 13 of the first adhesive tape 21 is irradiated with ultraviolet rays by scanning the point light source 52 spirally. Also in this case, the adhesive force of the area | region corresponding to the device area | region 13 of the 1st adhesive tape 21 can be reduced appropriately.

  In addition, the structure, method, and the like according to the above-described embodiment can be appropriately modified and implemented without departing from the scope of the object of the present invention.

DESCRIPTION OF SYMBOLS 11 Wafer 11a Front surface 11b Back surface 11c Concave part 13 Device area | region 15 Periphery surplus area | region 17 Device 21 1st adhesive tape 23 1st annular frame 25 Frame unit 31 2nd adhesive tape 33 2nd annular frame 2 Laser processing apparatus 4 Holding | maintenance Table 4a Holding surface 6 Clamp 8 Laser processing unit 12 Ultraviolet irradiation device 14 Case 14a Bottom plate portion 14b Side plate portion 16 Support plate 16a Light shielding portion 16b Transparent portion 18 Light source 22 Adhering device 24 Holding table 24a Holding surface 26 Clamp 28 Roller 32 Cutting Device 34 Holding table 34a Holding surface 36 Clamp 38 Cutting unit 40 Spindle 42 Cutting blade 52 Point light source

Claims (1)

A surface area is divided into a plurality of areas on a grid-like street, and a device area in which devices are formed in each area, and an outer peripheral surplus area surrounding the device area, the device area from the back side A method for processing a wafer having a recess formed by thinning,
A frame unit in which an ultraviolet curable first adhesive tape whose adhesive strength is reduced by irradiation of ultraviolet rays is attached to the front surface side of the wafer, and a first annular frame is mounted on the outer periphery of the first adhesive tape Forming steps;
After performing the frame unit forming step, the wafer is processed along the outer peripheral edge of the device region with a laser beam or a cutting blade, and the wafer is divided into the device region and the outer peripheral surplus region,
After performing the frame unit forming step, the region other than the region corresponding to the outer peripheral surplus region of the first adhesive tape is irradiated with ultraviolet rays, and the region corresponding to the device region of the first adhesive tape UV irradiation step to reduce the adhesive strength,
After performing the ultraviolet irradiation step and the dividing step, a second adhesive tape having a second annular frame attached to the outer peripheral portion is attached to the back side of the wafer excluding the outer peripheral excess region, and the device A sticking step for bringing the first pressure-sensitive adhesive tape and the second pressure-sensitive adhesive tape into a state of being stuck to the front surface side and the back surface side of the region,
After performing the adhering step, the space between the first annular frame and the second annular frame is widened, and the device region is moved to the first adhesive tape while leaving the outer peripheral surplus region on the first adhesive tape. A wafer processing method comprising: a peeling step of causing the second annular frame to support the device region by peeling the adhesive tape from one adhesive tape.