JP2011249589A - Processing method of wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing method of a wafer for allowing a reinforcement plate joined to a surface of the wafer to be easily removed after polishing a back surface of the wafer and embedding a through electrode in a device.SOLUTION: The processing method of the wafer comprises: a reinforcement plate joining step of joining a reinforcement plate 3 to a front face of a wafer 2 via a heat-resistant bond agent 4; a wafer polishing step of polishing a back surface 2b of the wafer 2 with a side, to which the reinforcement plate 3 is joined, being held on a chuck table 51 of a polishing device 5; an electrode forming step of forming a through electrode which communicates the back surface of the wafer 2 to which the reinforcement plate 3 is joined with an electrode formed on the device; a protective tape taping step of taping up the back surface 2b of the wafer 2 with a protective tape; and a reinforcement plate removing step of removing the reinforcement plate 3 by polishing the reinforcement plate 3 joined to the front surface of the wafer 2 with the side on which the protective tape taped on the back surface 2b of the wafer 2 being held on the chuck table 51 of the polishing device 5.

Description

  The present invention relates to a wafer processing method in which a back surface of a wafer having a plurality of devices formed on the front surface is ground to a predetermined thickness and then a through electrode communicating with an electrode formed on the device is embedded.

  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 semiconductors such as ICs and LSIs are divided into these partitioned regions. Form the device. Then, by cutting the semiconductor wafer along the street, the region where the semiconductor device is formed is divided to manufacture individual semiconductor devices.

  In order to reduce the size and increase the functionality of the device, a laminated device is laminated on the surface of a mother wafer on which a plurality of semiconductor devices are formed, and the electrodes provided on the laminated device are integrated into the semiconductor device formed on the surface of the mother wafer. A stacked semiconductor device connected to the provided electrode has been put into practical use. (For example, refer to Patent Document 1.)

  In the above-described laminated semiconductor device, in order to reduce the size and increase the functionality of the device, the laminated wafer on which the laminated device to be laminated on the surface of the mother wafer is formed to have a thickness of several tens of μm by grinding the back surface. Thereafter, a through hole (via hole) communicating with the electrode formed on the front surface from the back surface of the laminated wafer is provided, and the through electrode is embedded in the via hole. As described above, in the processing of the laminated wafer, the back surface of the laminated wafer is ground to form a thickness of several tens of μm before the via hole is provided and the electrode is embedded, so that the device formed on the surface of the laminated wafer is protected. Therefore, before grinding the back surface of the laminated wafer, a reinforcing plate is bonded to the surface of the laminated wafer via a bonding agent.

JP 2003-249620 A

  Thus, in a laminated wafer provided with a laminated device, a reinforcing plate is bonded to the front surface via a bonding agent and the back surface is ground as described above, and a via hole for embedding an electrode is drilled in the laminated device by laser processing. A through electrode is buried in the via hole. Since the laminated wafer is heated in the drilling of the via hole by this laser processing, it is necessary to use a material that can withstand a temperature of around 250 ° C. for the bonding agent that joins the reinforcing plate to the surface of the laminated wafer. For this reason, after joining the reinforcing plate to the surface of the laminated wafer via a bonding agent and grinding the back surface of the wafer, when removing the reinforcing plate from the laminated wafer, the reinforcing plate is heated to a temperature of 250 ° C. or higher, Since the reinforcing plate is detached while being slid along the surface of the wafer so that no load is applied to the laminated wafer, there is a problem that productivity is poor.

  The present invention has been made in view of the above-mentioned facts, and the main technical problem thereof is to grind the back surface of the wafer with a reinforcing plate bonded to the surface of the wafer on which a plurality of devices are formed on the surface. It is an object of the present invention to provide a wafer processing method in which a reinforcing plate bonded to the surface of a wafer can be easily removed after forming a thickness and embedding a through electrode in a device.

In order to solve the above-mentioned main technical problem, according to the present invention, the back surface of a wafer having a plurality of devices formed on the surface is ground to a predetermined thickness, and then the through electrode communicates with the electrode formed on the device. A method of processing a wafer to embed
Reinforcing plate mounting process for joining the reinforcing plate to the surface of the wafer via a heat-resistant bond agent,
A wafer grinding step of holding the reinforcing plate side of the wafer to which the reinforcing plate is bonded on the chuck table of the grinding device, grinding the back surface of the wafer and grinding the wafer to a predetermined thickness;
An electrode forming step of forming a through electrode that communicates with an electrode formed on the device from the back surface of the wafer in which the wafer grinding step is performed and the reinforcing plate is bonded to the surface;
A protective tape attaching step of attaching a protective tape to the back surface of the wafer on which the electrode forming step has been carried out;
A reinforcing plate removing step of holding the protective tape attached to the back surface of the wafer on the chuck table of the grinding apparatus and grinding the reinforcing plate bonded to the wafer surface to remove the reinforcing plate from the wafer surface; ,including,
A method for processing a wafer is provided.

After carrying out the above reinforcing plate removing step, a wafer supporting step is carried out, in which the protective tape side stuck to the back surface of the wafer is stuck to the surface of the dicing tape attached to the annular frame, and then the wafers are individually The wafer dividing process for dividing the device is performed.
The protective tape is a dicing tape attached to an annular frame, and the reinforcing plate removing step is performed with the wafer attached to the dicing tape, and then the wafer is divided into individual devices. Carry out wafer splitting process.

  In the wafer processing method according to the present invention, the wafer is ground to the predetermined thickness by grinding the back surface of the wafer to which the reinforcing plate is bonded via the heat-resistant bonding agent, and the device is started from the back surface of the wafer to which the reinforcing plate is bonded. After carrying out the electrode forming process of forming a through electrode that communicates with the electrode formed on the wafer, a protective tape is attached to the back surface of the wafer, and the protective tape side attached to the back surface of the wafer is placed on the chuck table of the grinding device. Since the reinforcing plate is removed from the surface of the wafer by holding and grinding the reinforcing plate that is bonded to the surface of the wafer, a load is applied to the wafer to remove the reinforcing plate that is bonded to the surface of the wafer. There is nothing. Accordingly, it is not necessary to heat the reinforcing plate to a temperature of 250 ° C. or higher in order to remove the reinforcing plate from the wafer surface, and to remove the reinforcing plate while sliding along the wafer surface so that no load is applied to the wafer. Productivity is improved.

The perspective view of the wafer processed by the processing method of the wafer by this invention. Explanatory drawing of the reinforcement plate mounting process in 1st Embodiment of the processing method of the wafer by this invention. Explanatory drawing of the wafer grinding process in 1st Embodiment of the processing method of the wafer by this invention. The perspective view seen from the back surface side of the wafer in which the electrode formation process in 1st Embodiment of the processing method of the wafer by this invention was implemented. Explanatory drawing of the masking tape sticking process in 1st Embodiment of the processing method of the wafer by this invention. Explanatory drawing which shows the reinforcement plate removal process in 1st Embodiment of the processing method of the wafer by this invention. The perspective view of the wafer in which the reinforcement plate removal process shown in FIG. 6 was implemented. The perspective view of the wafer in which the bond agent removal process in 1st Embodiment of the processing method of the wafer by this invention was implemented. Explanatory drawing which shows the wafer support process in 1st Embodiment of the processing method of the wafer by this invention. The principal part perspective view of the cutting device for implementing the wafer division | segmentation process in 1st Embodiment of the processing method of the wafer by this invention. Explanatory drawing which shows the wafer division | segmentation process in 1st Embodiment of the processing method of the wafer by this invention. The perspective view of the device divided | segmented by the wafer division | segmentation process in the processing method of the wafer by this invention. Explanatory drawing which shows the wafer support process in 2nd Embodiment of the processing method of the wafer by this invention. Explanatory drawing which shows the reinforcement plate removal process in 2nd Embodiment of the processing method of the wafer by this invention.

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

  FIG. 1 is a perspective view of a wafer processed by the wafer processing method according to the present invention. A wafer 2 shown in FIG. 1 is made of a disk-shaped silicon wafer having a thickness of, for example, 400 μm, and a plurality of regions are defined by streets 21 formed in a lattice shape on the surface 2a. Each device 22 is formed. A plurality of electrodes 221 protrude from the surface of the device 22 formed in this manner.

Hereinafter, a first embodiment of a wafer processing method in which the back surface of the wafer 2 described above is ground to a predetermined thickness and then a through electrode communicating with the electrode 221 formed in the device 22 is embedded will be described.
First, a reinforcing plate mounting step is performed in which a reinforcing plate is joined to the surface of the wafer 2 provided with a plurality of devices 22 via a heat-resistant bonding agent. That is, as shown in FIG. 2, the surface 3a of the reinforcing plate 3 made of a disk-shaped silicon substrate having a thickness of, for example, 500 μm is formed on the surface 2a of the wafer 2 through an epoxy-based bond agent 4 that can withstand a high temperature of 250 ° C. And join. In addition, it is desirable to use a silicon substrate with good workability as the reinforcing plate. The thickness of the bonding agent 4 is set to 20 μm, for example.

  If the above-described reinforcing plate mounting process is performed, the reinforcing plate 3 side of the wafer 2 to which the reinforcing plate 3 is bonded is held on the chuck table of the grinding device, and the back surface of the wafer 2 is ground to give the wafer a predetermined thickness. The wafer grinding process is performed. This wafer grinding process is carried out using the grinding apparatus shown in FIG. 3 in the illustrated embodiment. A grinding apparatus 5 shown in FIG. 3 includes a chuck table 51 that holds a workpiece, and a grinding means 52 that grinds a workpiece surface of the workpiece held on the chuck table 51. The chuck table 51 sucks and holds the workpiece on the upper surface and is rotated in the direction indicated by the arrow A in FIG. The grinding means 52 includes a spindle housing 521, a rotating spindle 522 that is rotatably supported by the spindle housing 521 and rotated by a rotation driving mechanism (not shown), a mounter 523 mounted on the lower end of the rotating spindle 522, and the mounter And a grinding wheel 524 attached to the lower surface of 523. The grinding wheel 524 includes an annular base 525 and a grinding wheel 526 that is annularly attached to the lower surface of the base 525, and the base 525 is attached to the lower surface of the mounter 523 with fastening bolts 527. ing.

  In order to perform the wafer grinding process using the grinding apparatus 5 described above, the reinforcing plate 3 bonded to the surface 2a of the wafer 2 on which the above-described reinforcing plate mounting process has been performed on the upper surface (holding surface) of the chuck table 51. The wafer 2 is sucked and held on the chuck table 51 via the reinforcing plate 3 by placing the back surface 3b side and operating a suction means (not shown). Accordingly, the back surface 2b of the wafer 2 sucked and held on the chuck table 51 via the reinforcing plate 3 is on the upper side. When the wafer 2 is sucked and held on the chuck table 51 in this way, the grinding wheel 524 of the grinding means 52 is rotated in the direction indicated by the arrow B, for example, 6000 rpm while the chuck table 51 is rotated in the direction indicated by the arrow A, for example, 300 rpm. The back surface 2b of the wafer 2 is ground by being rotated and rotated and brought into contact with the back surface 2b of the wafer 2, and the grinding wheel 524 is ground and fed downward at a grinding feed rate of 1 μm / second, for example, to a thickness of 30 μm, for example. .

  As described above, the wafer 2 that has been subjected to the wafer grinding process is formed to be extremely thin with a thickness of 30 μm. However, since the rigid reinforcing plate 3 is bonded to the surface, the wafer 2 is not curved. In addition, if the wafer grinding process mentioned above is implemented, the electrode formation process which forms the penetration electrode connected to the electrode 221 formed in the device 22 from the back surface of the wafer 2 with which the reinforcing plate 3 was joined to the surface will be implemented. This electrode formation step can be performed by a technique disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-119593. That is, as shown in FIG. 4, a via hole for embedding an electrode communicating with the electrode 221 (see FIG. 1) formed on the device 22 from the back surface of the wafer 2 is drilled by laser processing, and an insulating film is formed on the outer peripheral surface of the via hole. After the formation, the through electrode 222 is embedded in the via hole.

  If an electrode formation process was implemented as mentioned above, a protective tape sticking process of sticking a protective tape on the back surface of the wafer 2 is carried out. That is, as shown in FIGS. 5A and 5B, the protective tape 6 made of vinyl chloride or the like is attached to the back surface 2b of the wafer 2.

  Next, the protective tape 6 attached to the back surface of the wafer 2 is held on the chuck table of the grinding device, and the reinforcing plate 3 bonded to the surface of the wafer 2 is ground to reinforce the reinforcing plate from the surface of the wafer 2. The reinforcement plate removal process which removes 3 is implemented. This reinforcing plate removal step can be carried out using the grinding apparatus 5 shown in FIG. In order to carry out the reinforcing plate removing process using the grinding device 5, the protective tape 6 attached to the back surface 2b of the wafer 2 is placed on the upper surface (holding surface) of the chuck table 51 as shown in FIG. By operating a suction means (not shown), the wafer 2 is sucked and held on the chuck table 51 via the protective tape 6. Accordingly, the back surface 3b of the reinforcing plate 3 joined to the surface of the wafer 2 is the upper side. Thus, if the wafer 2 to which the reinforcing plate 3 is bonded on the chuck table 51 is sucked and held via the protective tape 6, the grinding table is rotated while rotating the chuck table 51 in the direction indicated by the arrow A at, for example, 300 rpm. The grinding wheel 524 of 52 is rotated in the direction shown by arrow B at, for example, 6000 rpm to contact the back surface 3b of the reinforcing plate 3 joined to the surface of the wafer 2, and the grinding wheel 524 is brought to a grinding feed rate of, for example, 1 μm / second. For example, 500 μm is ground and fed downward. As a result, the reinforcing plate 3 having a thickness of 500 μm is ground, and the reinforcing plate 3 is removed from the surface 2a of the wafer 2 as shown in FIG.

  In the reinforcing plate removing step described above, the reinforcing plate 3 joined to the surface of the wafer 2 is ground and removed, so that no load is applied to the wafer 2. Accordingly, the reinforcing plate 3 is heated to a temperature of 250 ° C. or higher in order to remove the reinforcing plate 3 from the surface of the wafer 2 as in the prior art described above, so that the load is not applied to the wafer 2. Productivity is improved because there is no need to detach while sliding along the surface. In the state in which the reinforcing plate removing step is performed, the bonding agent 4 is bonded to the surface 2a of the wafer 2 by bonding the surface 3a of the reinforcing plate 3 to the surface 2a of the wafer 2 in the reinforcing plate mounting step. Yes.

  Next, as shown in FIG. 7, the bonding agent 4 remaining on the surface 2a of the wafer 2 is removed by, for example, a solvent of methyl ethyl ketone (bonding agent removing step). As a result, as shown in FIG. 8, the bonding agent 4 remaining on the surface 2a of the wafer 2 is removed, and the device 22 formed on the surface 2a is exposed.

  If the bonding agent removing step described above is performed, a wafer supporting step is performed in which the protective tape 6 side attached to the back surface of the wafer 2 is attached to the surface of the dicing tape attached to the annular frame. That is, in the illustrated embodiment, as shown in FIGS. 9A and 9B, the wafer 2 is placed on the surface of the dicing tape 8 having an outer peripheral portion mounted so as to cover the inner opening of the annular frame 7. The protective tape 6 side stuck on the back side is stuck. In the illustrated embodiment, the dicing tape 8 has an acrylic resin paste of about 5 μm thick on the surface of a sheet base material made of polyvinyl chloride (PVC) having a thickness of 100 μm.

  Next, a wafer dividing process is performed in which the wafer 2 is cut along the streets 21 and divided into individual devices 22. This wafer dividing step is performed using the cutting apparatus shown in FIG. 10 in the illustrated embodiment. A cutting apparatus 9 shown in FIG. 10 includes a chuck table 91 that holds a workpiece, a cutting unit 92 that cuts the workpiece held on the chuck table 91, and a workpiece held on the chuck table 91. An image pickup means 93 for picking up images is provided. The chuck table 91 is configured to suck and hold the workpiece. The chuck table 91 is moved in a machining feed direction indicated by an arrow X in FIG. 10 by a cutting feed means (not shown) and is indicated by an arrow Y by an index feed means (not shown). It can be moved in the index feed direction shown.

  The cutting means 92 includes a spindle housing 921 disposed substantially horizontally, a rotating spindle 922 rotatably supported by the spindle housing 921, and a cutting blade 923 attached to the tip of the rotating spindle 922. The rotating spindle 922 is rotated in the direction indicated by the arrow C by a servo motor (not shown) disposed in the spindle housing 921. In the illustrated embodiment, the cutting blade 923 is an electroformed blade in which diamond abrasive grains having a particle diameter of 3 μm are hardened by nickel plating, and has a thickness of 20 μm. The imaging means 93 is attached to the tip of the spindle housing 921, and illuminates illuminating the workpiece, an optical system that captures an area illuminated by the illuminating means, and an image captured by the optical system. An image pickup device (CCD) or the like for picking up images is provided, and the picked-up image signal is sent to a control means described later.

  In order to carry out the wafer dividing step using the cutting device 9 described above, as shown in FIG. 10, the dicing tape 8 side on which the protective tape 6 attached to the back surface of the wafer 2 is attached on the chuck table 91 is shown. Is placed. Then, by operating a suction means (not shown), the wafer 2 is sucked and held on the chuck table 91 via the dicing tape 8 (wafer holding step). Accordingly, the surface 2a of the wafer 2 held on the chuck table 91 via the dicing tape 8 is on the upper side. In this way, the chuck table 91 that sucks and holds the wafer 2 via the dicing tape 8 is positioned directly below the imaging means 93 by a cutting feed means (not shown).

  When the chuck table 91 is positioned immediately below the image pickup means 93, an alignment operation for detecting a region to be processed of the wafer 2 is executed by the image pickup means 93 and a control means (not shown). That is, the imaging unit 93 and a control unit (not shown) perform alignment for aligning the street 21 formed in a predetermined direction of the wafer 2 and the cutting blade 923 (alignment process). Further, the alignment of the machining area is similarly performed on the street 21 formed on the wafer 2 in a direction orthogonal to the predetermined direction.

  If the alignment for detecting the processing region of the wafer 2 held on the chuck table 91 is performed as described above, the chuck table 91 holding the wafer 2 by suction is moved to the processing region below the cutting blade 923. Move to the processing start position. Then, as shown in FIG. 11 (a), one end of the street 21 to be processed of the wafer 2 (the left end in FIG. 11 (a)) is positioned so as to be located to the right by a predetermined amount from directly under the cutting blade 923 (processing). Feed start position positioning process). When the wafer 2 is positioned at the machining start position in the machining area in this way, the cutting blade 923 is rotated in the direction indicated by the arrow C while moving downward from the standby position indicated by the two-dot chain line in FIG. Cut and feed, and is positioned at a predetermined cut feed position as shown by the solid line in FIG. This cutting feed position is set to a position where the lower end of the outer peripheral edge of the cutting blade 923 reaches the protective tape 6 attached to the back surface of the wafer 2.

  Next, as shown in FIG. 11 (a), the chuck table 91 is moved in the direction indicated by the arrow X1 in FIG. 11 (a) while rotating the cutting blade 923 in the direction indicated by the arrow C at a rotational speed of 20000 rpm, for example. For example, machining feed is performed at a machining feed rate of 50 to 150 mm / sec. As a result, the wafer 2 is cut along the street 21 (laminated wafer dividing step). Then, when the other end of the wafer 2 held on the chuck table 91 (the right end in FIG. 11B) reaches a predetermined amount to the left of the cutting blade 923, the movement of the chuck table 91 is stopped. Then, the cutting blade 923 is raised and positioned at the retracted position indicated by the two-dot chain line.

  As described above, when the wafer dividing step is performed along all the streets 21 extending in the predetermined direction of the wafer 2, the chuck table 91 is rotated 90 degrees to be orthogonal to the predetermined direction. The wafer dividing step is performed along each street 21 formed in the direction of the above. As a result, the wafer 2 is divided into individual devices 22 along the street 21. Thus, the device 22 in which the wafer 2 is individually divided along the street 21 is peeled off from the protective tape 6 attached to the dicing tape 8. In the device 22 peeled from the protective tape 6 attached to the dicing tape 8, a through electrode 222 communicating with the electrode 221 is embedded as shown in FIG. The device 22 obtained in this way is sent to the next process, for example, a mounting process for joining to a mother board.

Next, a second embodiment of the wafer processing method according to the present invention will be described.
Also in the second embodiment, the reinforcing plate mounting step, the wafer grinding step, and the electrode forming step in the first embodiment are performed as described above. In the protective tape attaching step, as shown in FIG. 13, the dicing tape having the outer peripheral portion mounted so that the back surface 2 b of the wafer 2 on which the electrode forming step has been performed covers the inner opening of the annular frame 7. 8 is attached to the surface. Therefore, in the second embodiment, the dicing tape 8 with the back surface 2b of the wafer 2 having the reinforcing plate 3 bonded to the front surface functions as a protective tape.

  As described above, if the back surface 2b of the wafer 2 on which the electrode forming process has been performed is attached to the surface of the dicing tape 8 with the outer peripheral portion mounted so as to cover the inner opening of the annular frame 7, the above-described case is applied. A reinforcing plate removing step of grinding the reinforcing plate joined to the surface of the wafer in the first embodiment and removing the reinforcing plate from the surface of the wafer is performed. This reinforcing plate removing step can be performed using the grinding apparatus 5 shown in FIG. 3 as in the first embodiment. In order to perform the reinforcing plate removing process using the grinding device 5, as shown in FIG. 14, the dicing tape 8 functions as a protective tape having the back surface 2b of the wafer 2 adhered to the upper surface (holding surface) of the chuck table 51. The wafer 2 is sucked and held on the chuck table 51 via the dicing tape 8 by placing the side and operating a suction means (not shown). Accordingly, the back surface 3b of the reinforcing plate 3 joined to the surface of the wafer 2 is the upper side. In FIG. 14, the annular frame 7 on which the dicing tape 8 is mounted is omitted, but the annular frame 7 is held by an appropriate frame holding means provided on the chuck table 51. If the wafer 2 to which the reinforcing plate 3 is bonded on the chuck table 51 is sucked and held via the dicing tape 8, the chuck table 51 is moved in the direction indicated by the arrow A as in the embodiment shown in FIG. For example, while rotating at 300 rpm, the grinding wheel 524 of the grinding means 52 is rotated in the direction indicated by arrow B at, for example, 6000 rpm, and brought into contact with the back surface 3 b of the reinforcing plate 3 joined to the surface of the wafer 2. Is, for example, 500 μm ground and fed downward at a grinding feed rate of 1 μm / second, for example. As a result, the reinforcing plate 3 having a thickness of 500 μm is ground, and the reinforcing plate 3 is removed from the surface 2 a of the wafer 2.

  In the state where the reinforcing plate removing step is performed, the reinforcing plate 3 is placed on the surface 2a of the wafer 2 in the reinforcing plate mounting step as shown in FIG. 7 in the first embodiment. The bonding agent 4 joined to the surface 3a remains. Therefore, the bonding agent removing step of removing the bonding agent 4 remaining on the surface 2a of the wafer 2 with, for example, a solvent of methyl ethyl ketone is performed as in the first embodiment. Then, the wafer 2 is divided into individual devices 22 by performing the wafer dividing step in the first embodiment.

2: Wafer 22: Device 221: Electrode 222: Through electrode 3: Reinforcing plate 4: Bonding agent 5: Grinding device 51: Grinding device chuck table 52: Grinding means 524: Grinding wheel 6: Protective tape 7: Annular frame 8 : Dicing tape 9: Cutting device 91: Chuck table of cutting device 92: Cutting means

Claims (3)

A method of processing a wafer in which a back surface of a wafer having a plurality of devices formed on the front surface is ground to a predetermined thickness and then a through electrode communicating with an electrode formed on the device is embedded,
Reinforcing plate mounting process for joining the reinforcing plate to the surface of the wafer via a heat-resistant bond agent,
A wafer grinding step of holding the reinforcing plate side of the wafer to which the reinforcing plate is bonded on the chuck table of the grinding device, grinding the back surface of the wafer and grinding the wafer to a predetermined thickness;
An electrode forming step of forming a through electrode that communicates with an electrode formed on the device from the back surface of the wafer in which the wafer grinding step is performed and the reinforcing plate is bonded to the surface;
A protective tape attaching step of attaching a protective tape to the back surface of the wafer on which the electrode forming step has been carried out;
A reinforcing plate removing step of holding the protective tape attached to the back surface of the wafer on the chuck table of the grinding apparatus and grinding the reinforcing plate bonded to the wafer surface to remove the reinforcing plate from the wafer surface; ,including,
A method for processing a wafer.   After performing the reinforcing plate removing step, a wafer supporting step is performed in which the protective tape side attached to the back surface of the wafer is attached to the surface of the dicing tape attached to the annular frame. 2. The wafer processing method according to claim 1, wherein the wafer dividing step of dividing the device is performed.   The protective tape is a dicing tape mounted on an annular frame, and the reinforcing plate is removed while the wafer is attached to the dicing tape, and then the wafer is divided into individual devices. 2. The wafer processing method according to claim 1, wherein the step is performed.