JP4874602B2 - Adhesive tape used for wafer processing method and wafer processing method - Google Patents

Description

  The present invention relates to a wafer processing method in which a plurality of streets are formed in a lattice shape on the surface and a plurality of devices are formed in a plurality of regions partitioned by the plurality of streets, and an adhesive tape used for the wafer processing method About.

  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 semiconductor chips. In addition, optical device wafers with gallium nitride compound semiconductors laminated on the surface of a sapphire substrate are also divided into individual optical devices such as light emitting diodes and laser diodes by cutting along the streets, and are widely used in electrical equipment. ing.

Cutting along the streets of the above-described semiconductor wafer, optical device wafer, or the like is usually performed by a cutting device called a dicer. The cutting apparatus includes a chuck table for holding a workpiece such as a semiconductor wafer, a cutting means having a cutting blade for cutting the workpiece held on the chuck table, and a chuck table and the cutting means. And a processing feed means for moving the workpiece. The cutting means includes a spindle unit having a rotary spindle, a cutting blade mounted on the spindle, and a drive mechanism for driving the rotary spindle to rotate. (For example, refer to Patent Document 1.)
JP-A-7-106284

Further, as a method of dividing a wafer such as the above-described semiconductor wafer or optical device wafer along the street, a laser processing groove is formed by irradiating a pulse laser beam along the street formed on the wafer. A method of breaking along the line has been proposed. (For example, see Patent Document 2.)
JP-A-10-305420

  As described above, the wafer to be divided is formed to have a predetermined thickness by grinding or etching the back surface before cutting along the street. In recent years, it has been required to form a wafer with a thickness of 50 μm or less in order to reduce the weight and size of electrical equipment.

  Thus, when the thickness of the wafer is 50 μm or less, the wafer is easily broken, and there is a problem that handling of the wafer is difficult to handle.

  The present invention has been made in view of the above-mentioned facts, and its main technical problem is that even if the thickness of the wafer is reduced, the wafer is transported, disposed on an annular frame via an adhesive tape, cutting, etc. An object of the present invention is to provide a wafer processing method that is easy to handle and an adhesive tape used for the wafer processing method.

In order to solve the main technical problem, according to the present invention, a device region in which a plurality of streets are formed in a lattice shape on the surface and a plurality of devices are formed in a plurality of regions partitioned by the plurality of streets. And a wafer processing method comprising a surplus area surrounding the device area,
A region corresponding to the device region on the back surface of the wafer is removed to form a circular recess to form the thickness of the device region to a predetermined thickness, and a region corresponding to the surplus region on the back surface of the wafer remains. A reinforcing portion forming step for forming an annular reinforcing portion;
An adhesive tape mounting step in which an adhesive layer is formed on the surface and the outer peripheral surface of the adhesive tape having a plurality of through-holes is mounted so as to cover the opening of the annular frame;
On the chuck table formed with an outer diameter smaller than the inner diameter of the circular recess for sucking and holding the workpiece of the processing device on the back surface of the wafer adhering region of the adhesive tape mounted on the annular frame A frame fixing step of mounting and fixing the annular frame by a clamp disposed on the chuck table;
The back surface corresponding to the device area of the wafer is placed on the front surface of the wafer attachment area of the adhesive tape placed on the chuck table, and a suction force is applied to the suction holding area of the chuck table so that the adhesive tape Is sucked and held in the suction holding area, and the back surface corresponding to the device area of the wafer is sucked by applying a suction force to the wafer through the plurality of through-holes provided in the adhesive tape. Wafer sticking process to stick on the surface,
A surplus area removing step of cutting and removing the surplus area of the wafer adhered to the surface of the adhesive tape sucked and held in the suction holding area of the chuck table by a processing means of the processing apparatus;
A dividing step of cutting along the street the processing device of the processing apparatus the wafer from which the surplus region has been removed by being attached to the surface of the adhesive tape sucked and held in the suction holding region of the chuck table. ,
A method for processing a wafer is provided.

  In the reinforcing portion forming step, a region corresponding to the device region on the back surface of the wafer is ground to form a circular recess.

According to the present invention, even if the region corresponding to the device region on the back surface of the wafer is removed by forming the reinforcing portion forming step to form a circular recess and the thickness of the device region is reduced, Since the region corresponding to the surplus region is left and the annular reinforcing portion is formed and the rigidity is maintained, the wafer is not damaged during the conveyance of the wafer and the handling becomes easy. In addition, according to the present invention, since an adhesive tape having a plurality of through-holes is used, by applying a suction force to the suction holding region of the chuck table of the processing device without using a special tape sticking device, The wafer can be sucked through the plurality of through holes and attached to the surface of the adhesive tape. Further, according to the present invention, since the outer diameter of the chuck table is set smaller than the inner diameter of the circular recess formed by removing the region corresponding to the device region on the back surface of the wafer, the surplus on the back surface of the wafer An annular reinforcing portion corresponding to the region is not attached to the adhesive tape. Therefore, the excess area of the wafer can be smoothly cut and removed by the processing means of the processing apparatus in the excess area removing step.

Preferred embodiments of a wafer processing method and an adhesive tape used for the wafer processing method according to the present invention will be described below in more detail with reference to the accompanying drawings.
FIG. 1 is a perspective view of a semiconductor wafer as a wafer processed by the wafer processing method according to the present invention. A semiconductor wafer 10 shown in FIG. 1 is made of, for example, a silicon wafer having a thickness of 700 μm, and a plurality of streets 101 are formed in a lattice shape on the surface 10a, and a plurality of streets partitioned by the plurality of streets 101 are provided. A device 102 such as an IC or LSI is formed in the region. The semiconductor wafer 10 thus configured includes a device region 104 in which the device 102 is formed, and a surplus region 105 that surrounds the device region 104.

  As shown in FIG. 2, the protective member 11 is stuck on the surface 10a of the semiconductor wafer 10 configured as described above (protective member sticking step). Therefore, the back surface 10b of the semiconductor wafer 10 is exposed.

  When the protective member attaching step is performed, the region corresponding to the device region 104 on the back surface 10b of the semiconductor wafer 10 is removed to form the device region 104 with a predetermined thickness, and the back surface 10b of the semiconductor wafer 10 is formed. The reinforcement part formation process which leaves the area | region corresponding to the surplus area | region 105 in this, and forms a cyclic | annular reinforcement part is implemented. This reinforcing portion forming step is performed by the grinding apparatus 12 shown in FIG. 3A in the illustrated embodiment. A grinding apparatus 12 shown in FIG. 3A includes a grinding table 123 including a chuck table 121 that holds a workpiece and a grinding wheel 122 that grinds the workpiece held on the chuck table 121. Yes. In order to perform the reinforcing portion forming step using the grinding device 12, the protection member 11 of the semiconductor wafer 10 is placed on the chuck table 121, and the semiconductor wafer 10 is sucked and held on the chuck table 121. Here, the relationship between the semiconductor wafer 10 held on the chuck table 121 and the grinding wheel 122 will be described. The center of rotation P1 of the chuck table 121 and the center of rotation P2 of the grinding wheel 122 are eccentric, and the diameter of the grinding wheel 122 is the inside of the surplus area 105 of the semiconductor wafer 10 and the center of rotation P1 of the chuck table 121 (semiconductor wafer 10). The dimension is set to pass through the center. If the semiconductor wafer 10 is sucked and held on the chuck table 121, the grinding wheel 122 of the grinding means 123 is rotated at 6000 rpm in the direction indicated by the arrow 122a while the chuck table 121 is rotated at 300 rpm in the direction indicated by the arrow 121a. Contact the back surface of the semiconductor wafer 10. Then, the grinding means 123 is ground and fed downward by a predetermined amount at a predetermined grinding feed speed. As a result, on the back surface of the semiconductor wafer 10, as shown in FIG. 3B, a region corresponding to the device region 104 is ground and removed to form a circular recess 104b having a predetermined thickness (for example, 30 μm). At the same time, a region corresponding to the surplus region 105 remains and is formed in the annular reinforcing portion 105b. In addition, the circular recessed part 104b is formed in the internal diameter larger than the diameter of the chuck table of the cutting device mentioned later.

  As described above, even if the region corresponding to the device region 104 on the back surface of the semiconductor wafer 10 is removed and the thickness of the device region 104 is reduced by carrying out the reinforcing portion forming step, the semiconductor wafer 10 remains excessive. Since the region corresponding to the region 105 is left and the annular reinforcing portion 105b is formed and the rigidity is maintained, the semiconductor wafer 10 is not damaged during the transportation of the semiconductor wafer 10, and the handling becomes easy.

Next, a cutting apparatus as a processing apparatus for cutting the semiconductor wafer 10 along the street 101 will be described with reference to FIG.
A cutting apparatus 1 shown in FIG. 4 includes a stationary base 2 and a chuck table mechanism 3 that is disposed on the stationary base 2 so as to be movable in a direction indicated by an arrow X that is a machining feed direction and holds a workpiece. A spindle support mechanism 6 disposed on the stationary base 2 so as to be movable in a direction indicated by an arrow Y that is an indexing feed direction (a direction perpendicular to a direction indicated by an arrow X that is a machining feed direction), and the spindle support A spindle unit 7 serving as a cutting means (processing means) is provided in the mechanism 6 so as to be movable in a direction indicated by an arrow Z that is a cutting feed direction.

  The chuck table mechanism 3 includes a chuck table 4 that sucks and holds a workpiece, and a chuck table moving mechanism 5 that supports the chuck table 4 and moves it in a processing feed direction indicated by an arrow X. The chuck table moving mechanism 5 includes a pair of common guide rails 51 and 51 arranged in parallel along the machining feed direction indicated by the arrow X on the stationary base 2, and the arrow X on the guide rails 51 and 51. A chuck table support base 52 movably disposed in the processing feed direction shown in FIG. 5 and a work feed means 53 for moving the chuck table support base 52 along a pair of guide rails 51, 51. .

  The chuck table support base 52 is formed in a rectangular shape, and guided grooves 521 and 521 for fitting with the pair of guide rails 51 and 51 are formed on the lower surface thereof. By fitting the guided grooves 521 and 521 to the pair of guide rails 51 and 51, the chuck table support base 52 is disposed so as to be movable along the pair of guide rails 51 and 51.

  The processing feed means 53 includes a male screw rod 531 disposed in parallel between the pair of guide rails 51 and 51, and a drive source such as a servo motor 532 for rotationally driving the male screw rod 531. . One end of the male screw rod 531 is rotatably supported by a bearing block 533 fixed to the stationary base 2, and the other end is connected to the output shaft of the servo motor 532. The male screw rod 531 is screwed into a female screw 522 formed at the center of the chuck table support base 52. Therefore, the chuck table support base 52 is moved along the guide rails 51 and 51 in the machining feed direction indicated by the arrow X by driving the male screw rod 531 forward and backward by the servo motor 532.

Next, the chuck table 4 will be described with reference to FIGS.
The chuck table 4 shown in FIGS. 4 and 5 is rotatably supported by a cylindrical support cylinder 55 disposed on the upper surface of the chuck table support base 52 via a bearing 56 as shown in FIG. Yes. As shown in FIG. 5, the chuck table 4 includes a columnar main body 41 and an adsorption chuck 42 formed on a top surface of the main body 41 and formed by a porous member such as porous ceramics. The main body 41 is formed of a metal material such as stainless steel, and a circular fitting recess 411 is provided on the upper surface thereof. The fitting recess 411 is provided with an annular mounting shelf 412 on which the suction chuck 42 is mounted on the outer periphery of the bottom surface. The main body 41 is provided with a suction passage 413 that opens into the fitting recess 411, and the suction passage 413 communicates with a suction means (not shown). Accordingly, when a suction means (not shown) is operated, a negative pressure is applied to the fitting recess 411 through the suction passage 413. The chuck table 4 configured in this way is configured to be appropriately rotated by a rotation driving means (not shown). Note that a chamfer 414 is provided on the outer periphery of the upper end of the main body 41 of the chuck table 4.

  An annular groove 415 is formed in the upper part of the main body 41 constituting the chuck table 4. Four bases (see FIG. 4) of clamps 43 are disposed in the annular groove 415, and the bases of the clamps 43 are attached to the main body 41 by appropriate fixing means. A support table 57 is disposed on the upper end of the support cylinder 55.

  4, the spindle support mechanism 6 includes a pair of guide rails 61, 61 disposed on the stationary base 2 in parallel along the indexing feed direction indicated by the arrow Y, A movable support base 62 is provided on the guide rails 61 and 61 so as to be movable in the direction indicated by the arrow Y. The movable support base 62 includes a movement support portion 621 that is movably disposed on the guide rails 61, 61, and a mounting portion 622 that is attached to the movement support portion 621. A pair of guided grooves 621 a and 621 a that are fitted to the guide rails 61 and 61 are formed on the lower surface of the moving support portion 621. By fitting the guided grooves 621 a and 621 a to the guide rails 61 and 61, The movable support base 62 is configured to be movable along the guide rails 61 and 61. The mounting portion 622 is provided with a pair of guide rails 622a and 622a extending in the direction indicated by the arrow Z on one side surface in parallel.

  The spindle support mechanism 6 in the illustrated embodiment includes index feed means 63 for moving the movable support base 62 along the pair of guide rails 61 and 61 in the index feed direction indicated by the arrow Y. The index feeding means 63 includes a male screw rod 631 disposed in parallel between the pair of guide rails 61, 61, and a drive source such as a pulse motor 632 for rotationally driving the male screw rod 631. One end of the male screw rod 631 is rotatably supported by a bearing block (not shown) fixed to the stationary base 2, and the other end is connected to the output shaft of the pulse motor 632. The male screw rod 631 is screwed into a female screw hole formed in a female screw block (not shown) provided on the lower surface of the central portion of the moving support portion 621 constituting the movable support base 62. Therefore, when the male screw rod 631 is driven to rotate forward and reversely by the pulse motor 632, the movable support base 62 is moved along the guide rails 61 and 61 in the index feed direction indicated by the arrow Y.

  The spindle unit 7 in the illustrated embodiment includes a unit holder 71, a spindle housing 72 attached to the unit holder 71, and a rotating spindle 73 that is rotatably supported by the spindle housing 72. The unit holder 71 is provided with a pair of guided grooves 71a and 71a slidably fitted to a pair of guide rails 622a and 622a provided in the mounting portion 622. The guided grooves 71a and 71a By being fitted to the guide rails 622a and 622a, the guide rails 622a and 622a are supported so as to be movable in the infeed direction indicated by the arrow Z. The rotary spindle 73 is disposed so as to protrude from the tip of the spindle housing 72, and a cutting blade 74 is attached to the tip of the rotary spindle 73. The rotary spindle 73 to which the cutting blade 74 is attached is driven to rotate by a drive source such as a servo motor 75. A cutting water supply nozzle 76 that supplies cutting water to a cutting portion by the cutting blade 74 is disposed on both sides of the cutting blade 74. An image pickup means 77 for picking up an image of the work piece held on the chuck table 4 and detecting a region to be cut by the cutting blade 74 is provided at the tip of the spindle housing 72. The imaging means 77 is composed of optical means such as a microscope and a CCD camera, and sends the captured image signal to a control means (not shown).

  The spindle unit 7 in the illustrated embodiment includes a cutting feed means 78 for moving the holder 71 along the pair of guide rails 622a and 622a in the direction indicated by the arrow Z. The cutting feed means 78 includes a male screw rod (not shown) disposed between the guide rails 622a and 622a and a pulse for rotationally driving the male screw rod, similarly to the processing feed means 53 and the index feed means 63. A drive source such as a motor 782 is included, and a male screw rod (not shown) is driven to rotate forward and backward by a pulse motor 782, whereby the unit holder 71, the spindle housing 72, and the rotary spindle 73 are moved along the guide rails 622a and 622a with arrows. Move in the infeed direction indicated by Z.

The cutting apparatus 1 in the illustrated embodiment is configured as described above. Hereinafter, a processing method for cutting the semiconductor wafer 10 along the street 101 using the cutting apparatus 1 will be described.
First, an adhesive tape mounting process is performed in which an adhesive layer is formed on the surface and an outer peripheral surface of an adhesive tape having a plurality of through-holes is mounted so as to cover an opening of an annular frame. That is, as shown in FIG. 6A, the surface of the outer peripheral portion 130 of the adhesive tape 13 is mounted so as to cover the opening of the annular frame 14. As shown in FIG. 6B, the adhesive tape 13 has an adhesive layer 132 formed on the surface 131a of a synthetic resin sheet 131 such as polyolefin or vinyl chloride, and the synthetic resin sheet 131 and the adhesive layer by laser processing or the like. A plurality of through-holes 133 penetrating 132 are provided.

  Next, as shown in FIG. 7, the back surface 135b of the wafer attaching region 135 of the adhesive tape 13 attached to the annular frame 14 is placed on the suction chuck 42 of the chuck table 4, and the annular frame 14 is clamped. A frame fixing step of fixing by 43 is performed.

  When the frame fixing step described above is performed, the device region 104 of the semiconductor wafer 10 is applied to the surface 135a of the wafer attachment region 135 of the adhesive tape 13 placed on the chuck table 4 as shown in FIG. The corresponding back surface is placed, and suction force is applied to the suction holding area of the chuck table 4 to suck and hold the adhesive tape 13 to the suction holding area, and the semiconductor wafer 10 is sucked and adhered to the surface of the adhesive tape 13. A wafer attaching process is performed. That is, the back surface corresponding to the device region 104 of the semiconductor wafer 10 is placed on the front surface 135a of the wafer attaching region 135 of the adhesive tape 13 placed on the suction chuck 42, which is the suction holding region of the chuck table 4. Accordingly, the surface 10a of the semiconductor wafer 10 is on the upper side. At this time, the circular concave portion 104b formed by grinding and removing the region corresponding to the device region 104 on the back surface 10b of the semiconductor wafer 10 has an inner diameter larger than the outer diameter of the chuck table 4, and therefore, an excess. The annular reinforcing portion 105 b corresponding to the region 105 is not placed on the adhesive tape 13. Further, since the upper peripheral edge of the upper end of the main body 41 of the chuck table 4 is chamfered 414, the adhesive tape 13 is provided between the outer peripheral edge of the upper end of the main body 41 of the chuck table 4 and the annular reinforcing portion 105 b of the semiconductor wafer 10. Is never pinched. When a suction means (not shown) is operated, a negative pressure is applied to the fitting recess 411 through the suction passage 413. As a result, a suction force is applied to the upper surface (suction holding region) of the suction chuck 42 formed by the porous member. By acting, the adhesive tape 13 is sucked and held in the suction holding region, and a negative pressure is applied through the plurality of through-holes 133 provided in the adhesive tape 13 as shown in FIG. The semiconductor wafer 10 is sucked and adhered to the adhesive layer 132 of the adhesive tape 13. Thus, by using the adhesive tape 13, the semiconductor wafer 10 can be sucked and attached to the surface of the adhesive tape 13 without using a special tape attaching device.

  If the wafer sticking process mentioned above is implemented, as shown in FIG. 9, the protective member 11 stuck to the surface 10 (a) of the semiconductor wafer 10 will be peeled (protective member peeling process).

  If the wafer sticking step and the protective member peeling step described above are performed, the surplus region 105 of the semiconductor wafer 10 stuck to the surface of the adhesive tape 13 sucked and held in the suction holding region of the chuck table 4 is cut. Then, a surplus area removing step to be removed is performed. That is, by operating the machining feed means 53, the boundary between the device region 104 and the surplus region 105 of the semiconductor wafer 10 held on the chuck table 4 is positioned immediately below the cutting blade 74 as shown in FIG. I will. Then, the chuck table 4 is rotated in the direction indicated by the arrow, and the cutting blade 74 is rotated and fed in the direction indicated by the arrow Z1. As a result, as shown in FIG. 10B, the semiconductor wafer 10 is cut at the boundary between the device region 104 and the surplus region 105, and the surplus region 105 is removed.

,
If the above-described surplus area removing step is performed, the machining feed means 53 is operated to move the chuck table 4 to a position immediately below the imaging means 77. When the chuck table 4 is positioned immediately below the image pickup means 77, an alignment operation for detecting a processing region to be cut of the semiconductor wafer 10 is executed by the image pickup means 77 and a control means (not shown). That is, the imaging unit 77 and the control unit (not shown) are images such as pattern matching for aligning the street 101 formed in a predetermined direction of the semiconductor wafer 10 with the cutting blade 74 that cuts along the street 101. Execute the process and perform alignment of the machining area to be cut. In addition, the alignment of the machining area to be cut is similarly performed on the street 101 formed in the semiconductor wafer 10 and extending in a direction orthogonal to the predetermined direction.

  As described above, when the alignment operation for detecting the processing area to be cut of the semiconductor wafer 10 is executed, the semiconductor wafer 10 is adhered to the adhesive layer 112 of the adhesive tape 11 sucked and held in the suction holding area of the chuck table 4. A dividing step of cutting the semiconductor wafer 10 being cut along the street 101 is performed. That is, the chuck table 4 is moved to the cutting region, and one end of the predetermined street 101 is positioned slightly to the right in FIG. 11 from directly below the cutting blade 74 as shown in FIG. Then, while rotating the cutting blade 74, the cutting blade 74 is cut and fed by a predetermined amount in the direction indicated by the arrow Z1, and the machining feed means 53 is operated to move the chuck table 4 in the direction indicated by the arrow X1 in FIG. Move at the feed rate. The cut feed amount is set at a position reaching the back surface 10b (bottom surface) of the semiconductor wafer 10. Then, when the other end of the predetermined street 101 of the semiconductor wafer 10 held on the chuck table 4 reaches the left side slightly below the cutting blade 74 as shown in FIG. 11, the movement of the chuck table 4 is stopped, The cutting blade 74 is retracted in the direction indicated by the arrow Z2. As a result, the semiconductor wafer 10 is cut along a predetermined street 101.

  If the above-described dividing step is performed along all the streets 101 formed in the semiconductor wafer 10 in a predetermined direction, the chuck table 4 is rotated 90 degrees. Then, the above-described dividing step is performed along all the streets 101 formed on the semiconductor wafer 10 in a direction orthogonal to the predetermined direction. As a result, the semiconductor wafer 10 is cut along all the streets 101. Thus, by cutting along all the streets 101 of the semiconductor wafer 10, the semiconductor wafer 10 is divided into semiconductor chips for each device. In addition, since the semiconductor chip divided | segmented separately is affixed on the adhesive tape 11 with which the cyclic | annular flame | frame 14 was mounted | worn, it does not fall apart but the form of a wafer is maintained. The individual semiconductor chips thus divided are transported to the next process in a state where they are adhered to the adhesive tape 11 attached to the annular frame 14.

  Although the present invention has been described based on the illustrated embodiment, the present invention is not limited to the embodiment, and various modifications are possible within the scope of the gist of the present invention. For example, in the above-described embodiment, an example in which the surplus area removing process and the dividing process are performed by cutting is shown, but the surplus area removing process and the dividing process may be performed by laser processing.

The perspective view of the semiconductor wafer processed by the processing method of the wafer by this invention The perspective view which shows the state which affixed the protection member on the surface of the semiconductor wafer shown in FIG. Explanatory drawing of the reinforcement part formation process in the processing method of the wafer by this invention. The perspective view of the cutting device which enforces the processing method of the wafer by the present invention. FIG. 5 is a cross-sectional view of a main part of a chuck table equipped in the cutting apparatus shown in FIG. 4. Explanatory drawing of the adhesive tape mounting process in the processing method of the wafer by this invention. Explanatory drawing of the frame fixing process in the processing method of the wafer by this invention. Explanatory drawing of the wafer sticking 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 excess area | region removal 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.

Explanation of symbols

1: Cutting device 2: Stationary base 3: Chuck table mechanism 4: Chuck table 41: Chuck table main body 42: Suction chuck 43: Clamp 5: Chuck table moving mechanism 53: Work feed means 6: Spindle support mechanism 63: Indexing Feeding means 7: Spindle unit 72: Spindle housing 73: Rotating spindle 74: Cutting blade 77: Imaging means 78: Cutting feed means 10: Semiconductor wafer 101: Street 102; Device 11: Protection member 12: Grinding device 13: Adhering tape 131 : Synthetic resin sheet 132: Adhesive layer 133: Through pore 14: Annular frame

Claims (2)

A wafer having a device region in which a plurality of streets are formed in a lattice shape on the surface and a plurality of devices are formed in a plurality of regions partitioned by the plurality of streets, and a surplus region surrounding the device region A processing method,
A region corresponding to the device region on the back surface of the wafer is removed to form a circular recess to form the thickness of the device region to a predetermined thickness, and a region corresponding to the surplus region on the back surface of the wafer remains. A reinforcing portion forming step for forming an annular reinforcing portion;
An adhesive tape mounting step in which an adhesive layer is formed on the surface and the outer peripheral surface of the adhesive tape having a plurality of through-holes is mounted so as to cover the opening of the annular frame;
On the chuck table formed with an outer diameter smaller than the inner diameter of the circular recess for sucking and holding the workpiece of the processing device on the back surface of the wafer adhering region of the adhesive tape mounted on the annular frame A frame fixing step of mounting and fixing the annular frame by a clamp disposed on the chuck table;
The back surface corresponding to the device area of the wafer is placed on the front surface of the wafer attachment area of the adhesive tape placed on the chuck table, and a suction force is applied to the suction holding area of the chuck table so that the adhesive tape Is sucked and held in the suction holding area, and the back surface corresponding to the device area of the wafer is sucked by applying a suction force to the wafer through the plurality of through-holes provided in the adhesive tape. Wafer sticking process to stick on the surface,
A surplus area removing step of cutting and removing the surplus area of the wafer adhered to the surface of the adhesive tape sucked and held in the suction holding area of the chuck table by a processing means of the processing apparatus;
A dividing step of cutting along the street the processing device of the processing apparatus the wafer from which the surplus region has been removed by being attached to the surface of the adhesive tape sucked and held in the suction holding region of the chuck table. ,
A method for processing a wafer.   The wafer processing method according to claim 1, wherein in the reinforcing portion forming step, a region corresponding to the device region on the back surface of the wafer is ground to form a circular recess.

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