JP2012238658A - Wafer chamfering part removal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer chamfering part removal device capable of removing a chamfering part in a two-layer structure wafer in which a surface of the wafer is stuck to a substrate without damaging the substrate.SOLUTION: An wafer chamfering removal device comprises: a chuck table 34; a grinding unit; Z-axis direction feeding means for feeding the grinding unit in a Z-axis direction; Y-axis direction feeding means for relatively feeding the grinding unit in a Y-axis direction; Y-axis direction position detection means; Z-axis direction position detection means; imaging means for imaging a grinding region of a workpiece held in the chuck table 34; boundary height position direction means for detecting a height position of a boundary between a wafer 11 in a two-layer structure wafer 10 held in the chuck table 34 and a substrate 12; and control means. The control means controls the Z-axis direction feeding means on the basis of information for the height position of the boundary between the chamfering part to be removed of the wafer 11 and the substrate 12 detected by the boundary height position detection means.

Description

  The present invention relates to a wafer chamfered portion removing apparatus for removing a chamfered portion of a wafer in a two-layer structure wafer in which a wafer surface having a chamfered portion formed on the outer periphery is bonded to a substrate.

  In a semiconductor device manufacturing process, a large number of rectangular areas are defined by dividing lines called streets formed in a lattice shape on the surface of a semiconductor wafer having a substantially disk shape, and ICs, LSIs, etc. are divided into the rectangular areas. Form the device. Individual devices are formed by dividing the semiconductor wafer on which a large number of devices are formed in this manner along the streets. In order to reduce the size and weight of the device, the semiconductor wafer is usually ground to a predetermined thickness by cutting the semiconductor wafer along the street and dividing it into individual devices.

  However, since a chamfered portion is formed on the outer periphery of the wafer, if the back surface of the wafer is ground and thinned to a predetermined thickness, the remaining chamfered portion becomes a sharp so-called knife edge, which is dangerous and causes the wafer to be damaged. During grinding, there is a problem that a crack is generated from the knife edge and the wafer is damaged. In order to solve such a problem, a processing method has been implemented in which a chamfered portion of a wafer is cut and removed, and a back surface of the wafer from which the chamfered portion has been removed is ground to have a predetermined thickness.

  In addition, a wafer with a two-layer structure such as a back-illuminated CMOS image sensor in which the surface of the wafer on which the device is formed is supported by a glass substrate, a silicon substrate, or the like, or a Si through electrode that is problematic in the next process after thinning It is also effective to remove a chamfered portion of a wafer even in a two-layer structure wafer in which a wafer having a device having (TSV) formed on the surface is bonded with a substrate.

  In addition, if the chamfered portion of the wafer on which the device is formed is cut and removed, and the wafer surface is bonded to the substrate, the wafer surface is contaminated when the chamfered portion is cut and removed. Before bonding, it is necessary to clean the surface of the wafer. For this reason, after the surface of the wafer on which the device is formed is bonded to the substrate, the chamfered portion of the wafer is removed.

  Patent Document 1 discloses a method for grinding and removing a chamfered portion of a semiconductor wafer functioning as an active substrate in an SOI substrate obtained by bonding a semiconductor wafer functioning as a support substrate and a semiconductor wafer functioning as an active substrate. Have been described.

JP-A-8-107092

  Thus, in the above-described two-layer structure wafer in which the wafer surface is bonded to the substrate, there is a problem that the quality of the device is deteriorated if the substrate is damaged when the chamfered portion of the wafer is removed.

  The present invention has been made in view of the above-mentioned facts, and its main technical problem is that the substrate is damaged when the chamfered portion of the wafer in the two-layer structure wafer in which the wafer surface is bonded to the substrate is removed. It is an object of the present invention to provide a chamfered portion removing apparatus for a wafer that can remove a chamfered portion without any problem.

In order to solve the above-mentioned main technical problem, according to the present invention, a chamfered portion removing apparatus for a wafer that removes a chamfered portion of a wafer in a two-layer structure wafer in which the surface of a wafer having a chamfered portion formed on the outer periphery is bonded to a substrate. Because
A grinding tool having a chuck table having a holding surface for holding a workpiece, a chuck table driving motor for rotating the chuck table, and a grinding wheel for grinding the workpiece held on the holding surface of the chuck table And a grinding unit having a grinding tool drive motor for rotationally driving the grinding tool, and a Z-axis direction feeding means for moving the grinding unit and the chuck table relatively in the Z-axis direction perpendicular to the holding surface; Y-axis direction feed means for relatively moving the grinding unit and the chuck table in the Y-axis direction orthogonal to the Z-axis direction; Y-axis direction position detecting means for detecting the Y-axis direction position of the grinding tool; , Z-axis direction position detection means for detecting the position of the grinding tool in the Z-axis direction, and an image of the grinding area of the workpiece held on the holding surface of the chuck table Imaging means, boundary height position detecting means for detecting the height position of the boundary between the wafer and the substrate in the two-layer structure wafer held on the holding surface of the chuck table, and control means. ,
The control means operates the imaging means to detect a chamfered portion detecting step for detecting a chamfered portion to be removed from the wafer in a two-layer structure wafer in which the substrate side is held on the holding surface of the chuck table;
The boundary height position detecting means is operated and the chuck table driving motor is operated to rotate the chuck table so that the height position of the boundary between the chamfered portion to be removed from the wafer and the substrate is set every predetermined angle. A boundary height position detecting step to detect;
A grinding tool positioning step of positioning the grinding wheel of the grinding tool at a chamfer to be removed of the wafer in the two-layer structure wafer held on the chuck table by operating the Y-axis direction feeding means;
While operating the grinding tool drive motor to rotate the grinding tool, the chuck table drive motor is operated to rotate the chuck table, and the wafer in which the boundary height position detecting step has been performed is removed. A chamfered portion removing step for controlling the Z-axis direction feeding means based on height position information for each predetermined angle of the boundary portion between the power chamfered portion and the substrate is performed.
A chamfered portion removing apparatus for a wafer is provided.

Grinding wheel height position detecting means for detecting the height position of the lower end of the grinding wheel of the grinding tool is provided.
In addition, it is desirable that dressing means for dressing the grinding surface of the grinding wheel of the grinding tool is provided.

  The wafer chamfered portion removing apparatus according to the present invention operates a boundary height position detecting means for detecting a height position of a boundary portion between a wafer and a substrate in a two-layer structure wafer held on a holding surface of a chuck table. Wafer in which the height position of the boundary portion between the chamfered portion to be removed from the wafer and the substrate is detected at predetermined angles, the chuck table is rotated while the grinding tool is driven to rotate, and the boundary height position detecting step is performed. Since the Z-axis direction feeding means is controlled on the basis of the height position information for each predetermined angle between the chamfered portion to be removed and the substrate, the wafer is formed on the outer periphery without damaging the substrate to which the wafer is bonded. The chamfered portion can be removed.

The perspective view of the chamfering part removal apparatus of the wafer comprised by this invention. The perspective view which shows the principal part of the grinding unit with which the chamfer part removal apparatus of the wafer shown in FIG. 1 is equipped. The principal part expanded sectional view of the grinding tool which comprises the grinding unit shown in FIG. FIG. 2 is an explanatory view showing a relationship between an imaging unit and a boundary height position detection unit provided in the chamfered part removing apparatus for a wafer shown in FIG. 1 and a workpiece held on a chuck table. The block block diagram of the control means with which the chamfer part removal apparatus of the wafer shown in FIG. 1 is equipped. The figure which shows the height position information detected by the boundary part height position detection means with which the chamfer part removal apparatus of the wafer shown in FIG. 1 is equipped. Explanatory drawing of the chamfer part removal process implemented by the chamfer part removal apparatus of the wafer shown in FIG. Explanatory drawing of the dressing process implemented by the chamfer part removal apparatus of the wafer shown in FIG. The perspective view which shows other embodiment of the chamfer part removal apparatus of the wafer comprised by this invention. Explanatory drawing of the chamfer part removal process implemented by the chamfer part removal apparatus of the wafer shown in FIG. Explanatory drawing of the dressing process implemented by the chamfer part removal apparatus of the wafer shown in FIG.

  Hereinafter, a preferred embodiment of a chamfered portion removing apparatus for a wafer constituted according to the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a wafer chamfered portion removing apparatus constructed according to the present invention.
The wafer chamfered portion removing apparatus shown in FIG. 1 includes a stationary base 2. On the stationary base 2, a chuck table mechanism 3 that holds a workpiece and moves it in the X-axis direction indicated by an arrow X is disposed.

  The chuck table mechanism 3 in the illustrated embodiment includes a pair of guide rails 31, 31 disposed on the upper surface of the stationary base 2. The pair of guide rails 31 are extended in parallel with each other along the X-axis direction in FIG. A chuck table support base 32 is movably disposed on the pair of guide rails 31, 31. In other words, the chuck table support base 32 is provided with a pair of guided grooves 321 and 321, and by fitting the guided grooves 321 and 321 to the pair of guide rails 31 and 31, the chuck table support base 32. The base 32 is configured to be movable along a pair of guide rails 31, 31.

  A cylindrical member 33 is disposed on the chuck table support base 32, and a chuck table 34 is rotatably disposed at the upper end of the cylindrical member 33. The chuck table 34 includes a chuck table main body 341 and a suction chuck 342 disposed on the upper surface of the chuck table main body 341, and the chuck table main body 341 is rotatably supported by the cylindrical member 33. The suction chuck 342 is made of an appropriate porous material such as porous ceramics, and is connected to suction means (not shown). Accordingly, when a suction unit (not shown) is operated, a negative pressure is applied to the holding surface, which is the upper surface of the suction chuck 342, and the workpiece placed on the upper surface of the suction chuck 342 is sucked and held. The chuck table 34 is appropriately rotated by a pulse motor 340 as a chuck table drive motor disposed in the cylindrical member 33. A cover member 35 having a hole through which the chuck table 34 is inserted and covering the chuck table support base 32 is disposed at the upper end of the cylindrical member 33.

  1, the chuck table mechanism 3 in the illustrated embodiment includes an X-axis direction feeding means 36 for moving the chuck table 34 along the pair of guide rails 31 and 31 in the X-axis direction. I have. The X-axis direction feeding means 36 includes a male screw rod 361 disposed in parallel between the pair of guide rails 31, 31, a bearing 362 that rotatably supports one end of the male screw rod 361, and a male screw rod 361. A pulse motor 363 is connected to the end and drives the male screw rod 361 to rotate forward or backward. In the X-axis direction feeding means 36 configured as described above, the male screw rod 361 is screwed into the female screw 322 formed on the chuck table support base 32. Therefore, the X-axis direction feed means 36 drives the pulse motor 363 to drive the male screw rod 361 in the normal direction or the reverse direction, thereby moving the chuck table 34 disposed on the chuck table support base 32 to a pair of guides. It can move in the X-axis direction along the rails 31 and 31.

  The wafer chamfered portion removing apparatus in the illustrated embodiment includes X-axis direction position detecting means 37 for detecting the X-axis direction position of the chuck table 34. The X-axis direction position detecting means 37 is a linear scale 371 arranged along the guide rail 31 and a reading which is arranged on the chuck table support base 32 and moves along the linear scale 371 together with the chuck table support base 32. It consists of a head 372. In the illustrated embodiment, the reading head 372 of the X-axis direction position detecting means 37 sends a pulse signal of one pulse every 1 μm to the control means described later. Then, the control means described later counts the input pulse signals and detects the position of the chuck table 34 in the X-axis direction by detecting the amount of movement of the chuck table 34 from the reference position.

  The chamfered portion removing apparatus for a wafer in the illustrated embodiment includes a gate-type support frame 4 disposed along the Y-axis direction indicated by an arrow Y orthogonal to the X-axis direction across the pair of guide rails 31, 31. It has. The support frame 4 is provided with an opening 40 that allows movement of a chuck table 34 that is movably disposed along the pair of guide rails 31, 31, and a pair of guide rails 41, 41 is arranged along the Y-axis direction. Grinding means 5 is disposed on the upper portion of the front surface 4a of the support frame 4 thus configured. The grinding means 5 includes a Y-axis direction moving base 51 disposed so as to be movable in the Y-axis direction, and the Z-axis direction (holding the chuck table 34) indicated by an arrow Z perpendicular to the X-axis direction and the Y-axis direction. A Z-axis direction moving base 52 and a grinding unit 6 are provided so as to be movable in a direction perpendicular to the surface. The Y-axis direction moving base 51 is provided with guided grooves 511 and 511 which are fitted to the pair of guide rails 41 and 41 provided on the support frame 4 on the rear surface 51b. Is fitted to the pair of guide rails 41, 41 so as to be movable in the Y-axis direction along the pair of guide rails 41, 41. A pair of guide rails 512 and 512 are provided on the front surface 51 a of the X-axis direction moving base 51 along the Z-axis direction perpendicular to the holding surface of the chuck table 34. The Y-axis direction moving base 51 configured as described above is moved in the Y-axis direction along the pair of guide rails 41 and 41 by the Y-axis direction feeding means 53. The Y-axis direction feeding means 53 includes a male screw rod 531 disposed in parallel between the pair of guide rails 41, a bearing 532 that rotatably supports one end of the male screw rod 531, and a male screw rod 531. A pulse motor 533 is connected to the end and drives the male screw rod 531 to rotate forward or backward. The Y-axis direction feeding means 53 configured as described above is screwed into a female screw (not shown) formed on a protruding portion provided with a male screw rod 531 protruding from the rear surface of the Y-axis direction moving base 51. The Therefore, the Y-axis direction feeding means 53 drives the pulse motor 533 to drive the male screw rod 531 in the normal direction or the reverse direction, so that the Y-axis direction feeding means 53 moves along the Y-axis direction moving base 51 along the pair of guide rails 41, 41. It can move in the axial direction.

  The Z-axis direction moving base 52 is provided with guided grooves 521 and 521 that fit with a pair of guide rails 512 and 512 provided on the front surface 51a of the Y-axis direction moving base 51 on the rear surface 52b. The guided grooves 521 and 521 are fitted to the pair of guide rails 512 and 512 so as to be movable along the pair of guide rails 512 and 512 in the Z-axis direction. The Z-axis direction moving base 52 configured in this way is moved in the Z-axis direction along the pair of guide rails 512 and 512 by the Z-axis direction feeding means 54. The Z-axis direction feeding means 54 includes a male screw rod 541 disposed in parallel between the pair of guide rails 512 and 512, a bearing (not shown) that rotatably supports one end of the male screw rod 541, a male screw A pulse motor 543 is connected to the other end of the screw rod 541 and drives the male screw rod 541 to rotate forward or backward. The thus configured Z-axis direction feeding means 54 is screwed into a female screw (not shown) formed on a protruding portion provided with a male screw rod 541 protruding from the rear surface of the Z-axis direction moving base 52. The Therefore, the Z-axis direction feeding means 54 drives the pulse motor 543 to drive the male screw rod 541 in the normal direction or the reverse direction, thereby moving the Z-axis direction moving base 52 along the pair of guide rails 512 and 512. It can move in the Z-axis direction.

  A grinding unit support member 55 for supporting the grinding unit 6 is mounted on the front surface 52 a of the Z-axis direction moving base 52. The grinding unit support member 55 is formed in an L shape, and includes an attachment portion 551 and a support portion 552 that extends horizontally from the lower end of the attachment portion 551 at a right angle. The grinding unit support member 55 configured as described above has the attachment portion 551 attached to the front surface 52 a of the Z-axis direction moving base 52. The attachment portion 551 is provided with four long holes 551a that are long in the Z-axis direction, and the fastening bolts 553 that are respectively inserted through the four long holes 551a are provided on the Z-axis direction moving base 52. It is attached to the front surface 52a. The support portion 552 constituting the grinding unit support member 55 is provided with four long holes 552a that are long in the X-axis direction, and fastening bolts that are respectively inserted through the four long holes 552a. The spindle housing 61 of the grinding unit 6 is attached to the lower surface of the support portion 552 by 554.

The grinding unit 6 mounted on the lower surface of the support portion 552 constituting the grinding unit support member 55 as described above will be described with reference to FIGS. 2 and 3.
The grinding unit 6 in the illustrated embodiment is mounted on a spindle housing 61 mounted on the lower surface of the support portion 552, a rotating spindle 62 rotatably supported on the spindle housing 61, and a front end portion of the rotating spindle 62. A clamping bolt 64 for mounting the mounter (not shown), a grinding tool 65 attached to the mounter (not shown) attached by the fastening bolt 64, and a clamp for clamping and fixing the grinding tool 65 to a flange of the mounter (not shown) A nut 66 is used. The rotary spindle 62 is configured to be rotated by a servo motor 67 (see FIG. 1) as a grinding tool drive motor. As shown in FIG. 3, the grinding tool 65 includes an annular base 651 and an annular grinding wheel 652 mounted on the outer peripheral side surface of the annular base 651. The annular grinding wheel 652 is formed to have a thickness of 2 mm, for example, and the outer peripheral surface is flat in the Y-axis direction, that is, the outer peripheral surface is formed perpendicular to the side surface.

  The wafer chamfered portion removing apparatus in the illustrated embodiment includes Y-axis direction position detecting means 68 for detecting the Y-axis direction position of the grinding wheel 652 constituting the grinding tool 65 of the grinding unit 6. The Y-axis direction position detecting means 68 includes a linear scale 681 provided along the guide rail 41 provided on the support frame 4, and a Y-axis direction moving base 51, together with the Y-axis direction moving base 51. The reading head 682 moves along a linear scale 681. In the illustrated embodiment, the reading head 682 of the Y-axis direction position detecting means 68 sends a pulse signal of one pulse every 1 μm to the control means described later. The control means described later counts the input pulse signals and detects the position of the grinding wheel 652 in the Y-axis direction by detecting the amount of movement of the grinding unit 6 from the reference position.

  The wafer chamfered portion removing apparatus in the illustrated embodiment includes Z-axis direction position detecting means 69 for detecting the Z-axis direction position of the grinding wheel 652 constituting the grinding tool 65 of the grinding unit 6. The Z-axis direction position detecting means 69 includes a linear scale 691 provided along the guide rail 511 provided on the Y-axis direction moving base 51 and a Z-axis direction moving base 52 provided on the Z-axis direction moving base 52. The reading head 692 moves along the linear scale 691 together with the base 52. In the illustrated embodiment, the reading head 692 of the Z-axis direction position detecting means 69 sends a pulse signal of one pulse every 1 μm to the control means described later. And the control means mentioned later counts the input pulse signal, and detects the Z-axis direction position of the grinding wheel 652 by detecting the movement amount from the reference position of the grinding unit 6.

  With reference to FIG. 1, the wafer chamfer removing device in the illustrated embodiment is arranged in the spindle housing 61 of the grinding unit 6 and has a processing area to be ground by the grinding wheel 652 of the grinding tool 65. Detects the height position of the boundary between the wafer and the substrate, that is, the lower surface of the wafer in a two-layer structure wafer in which the surface of a wafer described later held on the chuck table 34 and the imaging means 71 for detection is bonded to the substrate. For this purpose, a boundary height position detecting means 72 is provided. The imaging means 71 and the boundary height position detecting means 72 will be described with reference to FIG. The imaging means 71 and the boundary height position detection means 72 are disposed in a case 70 attached to the spindle housing 61. The imaging means 71 is composed of an optical system such as a microscope and an imaging device (CCD) and the like, and serves as a workpiece to be held on the chuck table 34 through a half mirror 73 and an objective lens 74 disposed in the case 70. The two-layer structure wafer 10 is imaged, and the imaged image signal is sent to the control means described later. The two-layer wafer 10 has a configuration in which the surface of the wafer 11 is bonded to the substrate 12. Note that chamfered portions 111 and 121 are formed on the outer circumferences of the wafer 11 and the substrate 12 constituting the two-layer structure wafer 10, respectively.

  The boundary height position detection means 72 is applied to the wafer 11 in the two-layer structure wafer 10 held on the chuck table 34 through the half mirror 73 and the objective lens 74 with detection light having a wavelength transmissive to the wafer. A height position detector that obtains the height position of the lower surface of the wafer 11 based on the difference between the optical path length of the reflected light that is irradiated and reflected by the lower surface of the wafer 11 and the reference optical path length can be used. The boundary height position detection means 72 sends a detection signal to a control means described later. As the boundary height position detecting means 72 described above, for example, “reflected spectral film thickness meter FE-3000” manufactured and sold by Otsuka Electronics Co., Ltd. can be used.

  Referring back to FIG. 1, the wafer chamfered portion removing apparatus in the illustrated embodiment is disposed on the upper surface of the cover member 35 that covers the chuck table support base 32 constituting the chuck table mechanism 3 and is a grinding tool. Grinding wheel height position detecting means 75 for detecting the height position of the lower end of 65 grinding wheels 652 is provided. The grinding wheel height position detecting means 75 has a light emitting element 751 and a light receiving element 752 which are arranged to face each other at a predetermined interval, and a voltage corresponding to the amount of light received by the light receiving element 752. A photoelectric converter (not shown) for conversion, and outputs a voltage signal corresponding to the amount of light received by the photoelectric converter to a control means described later. In order to detect the height position of the lower end of the grinding wheel 652 by the grinding wheel height position detection means 75 configured as described above, the grinding wheel height position detection means 75 is positioned directly below the grinding wheel 652, and the Z axis Based on the detection signal from the photoelectric converter when the grinding wheel 652 is lowered by operating the direction feed means 54 and the grinding wheel 652 blocks between the light emitting element 751 and the light receiving element 752, It is obtained from the position signal from the detecting means 69.

  Dressing means 76 for dressing the outer peripheral surface (grinding surface) of the grinding wheel 652 of the grinding tool 65 is arranged on the upper surface of the cover member 35 that covers the chuck table support base 32 constituting the chuck table mechanism 3. It is installed. The dressing means 76 includes a dressing board 761 and a support member 762 that supports the dressing board 761, and the support member 762 is attached to the upper surface of the cover member 35.

  The wafer chamfered portion removing apparatus in the illustrated embodiment includes a control means 20 as shown in FIG. The control means 20 is configured by a computer, and a central processing unit (CPU) 201 that performs arithmetic processing according to a control program, a read-only memory (ROM) 202 that stores control programs and the like, and a read / write that stores arithmetic results and the like. A random access memory (RAM) 203, an input interface 204, and an output interface 205 are provided. The input interface 204 of the control unit 20 configured as described above includes a read head 372 of the X-axis direction position detection unit 37, a read head 682 of the Y-axis direction position detection unit 68, and a read head of the Z-axis direction position detection unit 69. 692, detection signals from the imaging means 71, the boundary height position detecting means 72, the grinding wheel height position detecting means 75, and the like are input. Further, from the output interface 205, a pulse motor 340 as a chuck table driving motor for rotationally driving the chuck table 34, a servo motor 363 of the X-axis direction feeding means 36, a pulse motor 533 of the Y-axis direction feeding means 53, a Z-axis direction. A control signal is output to a pulse motor 543 of the feeding means 54, a servo motor 67 as a grinding tool drive motor that rotationally drives the grinding tool 65, and the like.

The chamfered portion removing apparatus for a wafer in the illustrated embodiment is configured as described above, and the operation thereof will be described below.
First, the substrate 12 side of the two-layer structure wafer 10 is placed on the chuck table 34, and the two-layer structure wafer 10 is sucked and held on the chuck table 34 by operating a suction means (not shown). Therefore, in the two-layer structure wafer 10 held on the chuck table 34, the wafer 11 is on the upper side. When the two-layer structure wafer 10 is sucked and held on the chuck table 34 in this way, the chuck table 34 that sucks and holds the two-layer structure wafer 10 by operating the X-axis direction feeding means 36 is shown in FIG. The imaging unit 71 and the boundary height position detection unit 72 are positioned directly below the objective lens 74 disposed in the case 70 that houses the imaging unit 71 and the boundary height position detection unit 72. Then, the Z-axis direction feeding unit 54 is operated to position the center of the imaging screen by the imaging unit 71 at a position, for example, 1 mm inside from the outer peripheral edge of the wafer 11 constituting the two-layer structure wafer 10 (chamfered portion detection step).

  Next, the boundary height position detecting means 72 is operated, and the pulse motor 340 as a chuck table driving motor is operated to rotate the chuck table 34 once. As a result, the height position of the lower surface of the wafer 11 (the height position from the upper surface of the chuck table 34), which is the boundary portion between the wafer 11 and the substrate 12 constituting the two-layer structure wafer 10 by the boundary height position detecting means 72. ) Is detected once and sent to the control means 20 as shown in FIG. The control means 20 temporarily stores the height position information shown in FIG. 6 in the random access memory (RAM) 203 (boundary height position detection step).

  If the boundary height position detection step is performed as described above, the chuck table 34 holding the two-layer structure wafer 10 is moved to a processing region by the grinding tool 65, and the wafer is shown in FIG. For example, a position 1 mm inside from the outer peripheral edge at the 0 degree position on the outer peripheral portion of 11 is positioned directly below the outer edge of the grinding wheel 652 constituting the grinding tool 65 (grinding tool positioning step). Then, the Z-axis direction feeding means 54 is operated while rotating the servo motor 67 as a grinding tool drive motor to rotate the grinding tool 65 in the direction indicated by the arrow 65a (the clockwise direction when the grinding wheel 652 is viewed from the front). The grinding tool 65 is actuated to lower and the lower surface (outer peripheral edge) of the grinding wheel 652 is stored in the random access memory (RAM) 203. The height at the 0 degree position of the wafer 11 in the height position information shown in FIG. (In the illustrated embodiment, the position is 235 μm from the upper surface of the chuck table 34). In this way, when positioning the lower surface (outer peripheral edge) of the grinding wheel 652 at the height position at the 0 degree position of the wafer 11, the control means 20 is based on the detection signal from the Z-axis direction position detection means 69. The direction feed means 54 is controlled. Next, while rotating the grinding tool 65 in the direction shown by the arrow 65a, the pulse motor 340 as the chuck table driving motor is operated to move the chuck table 34 in the direction shown by the arrow 34a (clockwise when the chuck table 34 is viewed from the front). Direction). In this way, when the chuck table 34 is rotated once, the control means 20 is based on the height position data shown in FIG. 6 and the Z-axis direction feeding means 54 is set to a height position corresponding to each rotation angle. To control. As a result, as shown in FIG. 7B, the chamfered portion 111 formed on the outer periphery of the wafer 11 is ground and removed (chamfered portion removing step). In this chamfered portion removing step, the Z-axis direction feeding means 54 is controlled so that the grinding tool 65 is at a height position corresponding to each rotation angle based on the height position data shown in FIG. The chamfered portion 111 formed on the outer periphery of the wafer 11 can be removed without damaging the substrate 12 to which is bonded.

  When the center of the two-layer structure wafer 10 is not accurately held at the center of the chuck table 34, the outer periphery of the two-layer structure wafer 10 is slightly displaced in the Y-axis direction when the chuck table 34 is rotated. This displacement in the Y-axis direction is detected every time the two-layer structure wafer 10 rotates, for example, once in the chamfered portion detection step, and the detected displacement data is temporarily stored in a random access memory (RAM) 203. When performing the chamfered portion removing step, it is desirable to control the Y-axis direction feeding means 53 based on the displacement data to displace the grinding wheel 652 constituting the grinding tool 65.

  When the chamfered portion removing step described above is performed, the outer peripheral portion of the grinding wheel 652 constituting the grinding tool 65 is worn away. As a result, the outer peripheral surface of the grinding wheel 652 is not flat in the Y-axis direction, that is, the outer peripheral surface is not perpendicular to the side surface. For this reason, if the chamfered portion removing step is performed, a dressing step is performed in which the outer peripheral surface of the grinding wheel 652 is dressed and corrected flatly in the Y-axis direction. In this dressing step, the dressing board 761 of the dressing means 76 is moved to a processing area by the grinding tool 65, and the Z-axis direction feeding means 54 is operated while rotating the grinding tool 65 in the direction indicated by the arrow 65a as shown in FIG. Then, the grinding tool 65 is lowered, the outer peripheral surface (grinding surface) of the grinding wheel 652 is brought into contact with the dressing board 761 and pressed with a predetermined pressure, and the Y-axis direction feeding means 53 is operated to move the grinding tool 65 in the Y-axis direction. It is carried out by moving to. As a result, the outer peripheral surface (grinding surface) of the grinding wheel 652 is corrected to be flat in the Y-axis direction, that is, perpendicular to the side surface.

  When the dressing process is performed as described above, the outer diameter of the grinding wheel 652 decreases, and thus the height position of the lower end of the grinding wheel 652 changes. In order to detect a change in the height position of the lower end of the grinding wheel 652, the height position detecting means 75 is positioned directly below the grinding wheel 652 on which the dressing process has been performed. Then, the Z-axis direction feeding means 54 is operated to lower the grinding tool 65, and the outer peripheral portion of the grinding wheel 652 is inserted between the light emitting element 751 and the light receiving element 752 of the height position detecting means 75, and the grinding wheel 652 is inserted. Based on the detection signal from the photoelectric converter at the time when the light is blocked, the height position of the lower surface of the grinding wheel 652 is obtained by the position signal from the Z-axis direction position detecting means 69. Based on the height position of the lower surface of the grinding wheel 652 detected in this way, the control means 20 corrects the control of the Z-axis direction feeding means 54 in the chamfered portion removing step.

Next, another embodiment of a wafer chamfered portion removing apparatus constructed according to the present invention will be described with reference to FIG. The chamfered portion removing apparatus for a wafer shown in FIG. 8 may be substantially the same except that the chamfered portion removing apparatus for a wafer shown in FIGS. 1 to 4 is different from the grinding unit. The description is omitted.
The grinding unit 8 of the wafer chamfered portion removing apparatus shown in FIG. 9 includes a spindle housing 81 mounted on the front surface 52a of the Z-axis direction moving base 52, and a rotating spindle 82 rotatably disposed on the spindle housing 81. And a servo motor 83 as a grinding tool drive motor for driving the rotary spindle 82 to rotate. A lower end portion of the rotary spindle 82 protrudes downward beyond the lower end of the spindle housing 81, and a mounter 84 is provided at the lower end. A grinding tool 85 is attached to the lower surface of the mounter 84. The grinding tool 85 includes an annular base 851 and a grinding wheel 852 that is annularly attached to the lower surface of the base 851, and the annular base 851 is attached to the mounter 84 by fastening bolts 86. The annular grinding wheel 852 has a thickness of 3 mm, for example, and a lower surface formed in a plane.

The wafer chamfer removing apparatus shown in FIG. 9 is configured as described above, and the operation thereof will be described below.
In the wafer chamfer removing apparatus shown in FIG. 9, as described above, the substrate 12 side of the two-layer structure wafer 10 is placed on the chuck table 34, and a suction means (not shown) is operated to operate the chuck table 34. The two-layer structure wafer 10 is sucked and held on the top. And the boundary part height position detection process mentioned above is implemented as mentioned above.

  When the boundary height position detection step is performed, the chuck table 34 holding the two-layer structure wafer 10 is moved to a processing region by the grinding tool 85, and the outer peripheral portion of the wafer 11 is shown in FIG. For example, a position 1 mm inside from the outer peripheral edge at the 0 degree position is positioned directly below the outer peripheral edge of the grinding wheel 852 constituting the grinding tool 85 (grinding tool positioning step). Then, while rotating the grinding tool 85 in the direction indicated by the arrow 85a (the clockwise direction when the grinding tool 85 is viewed from the front), the Z-axis direction feeding means 54 is operated to lower the grinding tool 85, and the grinding wheel 852 Is positioned at a height of the wafer 11 at the 0 degree position (in the illustrated embodiment, a position of 235 μm from the upper surface of the chuck table 34). In this way, when the lower surface of the grinding wheel 852 is positioned at the height position at the 0 degree position of the wafer 11, the control means 20 is based on the detection signal from the Z-axis direction position detection means 69 and the Z-axis direction feed means 54. To control. Next, the pulse motor 340 is operated while rotating the grinding tool 85 in the direction indicated by the arrow 85a, and the chuck table 34 is rotated once in the direction indicated by the arrow 34a (clockwise direction when the chuck table 34 is viewed from the front). . In this way, when the chuck table 34 is rotated once, the control means 20 is based on the height position data shown in FIG. 6 and the Z-axis direction feeding means 54 is set to a height position corresponding to each rotation angle. To control. As a result, as shown in FIG. 10B, the chamfered portion 111 formed on the outer periphery of the wafer 11 is ground and removed (chamfered portion removing step). In this chamfer removal step, the Z-axis direction feeding means 54 is controlled so that the grinding tool 85 is at a height position corresponding to each rotation angle based on the height position data shown in FIG. It is possible to remove the chamfered portion 111 formed on the outer periphery of the wafer 11 without damaging the substrate 12 to which is bonded.

  Also in the wafer chamfered portion removing apparatus shown in FIG. 9, if the center of the two-layer structure wafer 10 is not accurately held at the center of the chuck table 34, the outer periphery of the two-layer structure wafer 10 can be obtained by rotating the chuck table 34. Is slightly displaced in the Y-axis direction. This displacement in the Y-axis direction is detected every time the two-layer structure wafer 10 rotates, for example, once in the chamfered portion detection step, and the detected displacement data is temporarily stored in a random access memory (RAM) 203. Then, when performing the chamfered portion removing step, it is desirable to control the Y-axis direction feeding means 53 based on the displacement data to displace the grinding wheel 852 constituting the grinding tool 85.

  When the chamfered portion removing process described above is performed, the lower surface portion of the grinding wheel 852 constituting the grinding tool 85 is worn away. As a result, the lower surface of the grinding wheel 852 is not flat. For this reason, if the chamfer part removal process is implemented, the dressing process which dresses the lower surface of the grinding wheel 852 and corrects it to a plane will be implemented. In this dressing process, the dressing board 761 of the dressing means 76 is moved to a processing region by the grinding tool 65, and the Z-axis direction feeding means 54 is operated while rotating the grinding tool 85 in the direction indicated by the arrow 85a as shown in FIG. Then, the grinding tool 85 is lowered, the lower surface of the grinding wheel 852 is brought into contact with the dressing board 761 and pressed with a predetermined pressure, and the Y-axis direction feeding means 53 is operated to move the grinding tool 85 in the Y-axis direction. carry out. As a result, the lower surface (grinding surface) of the grinding wheel 852 is corrected to a flat surface.

  When the dressing process is performed as described above, the outer diameter of the grinding wheel 852 decreases, and the height position of the lower surface of the grinding wheel 852 changes. In order to detect a change in the height position of the lower surface of the grinding wheel 852, the height position detecting means 75 is positioned directly below the grinding wheel 852 subjected to the dressing process. Then, the Z-axis direction feeding means 54 is operated to lower the grinding tool 85, and the outer peripheral portion of the grinding wheel 852 is inserted between the light emitting element 751 and the light receiving element 752 of the height position detecting means 75, and the grinding wheel 852 is inserted. The height position of the lower surface of the grinding wheel 852 is obtained from the position signal from the Z-axis direction position detecting means 69 based on the detection signal from the photoelectric converter at the time when the light is blocked. Based on the height position of the lower surface of the grinding wheel 852 detected in this way, the control means 20 corrects the control of the Z-axis direction feeding means 54 in the chamfered portion removing step.

2: stationary base 3: chuck table mechanism 32: chuck table support base 34: chuck table 340: pulse motor 36 as a chuck table drive motor 36: X-axis direction feed means 37: X-axis direction position detection means 5: grinding means 51: Y-axis direction moving base 52: Z-axis direction moving base 53: Y-axis direction feeding means 54: Z-axis direction feeding means 6: Grinding unit 65: Grinding tool 652: Annular grinding wheel 67: Grinding tool drive motor Servo motor 68: Y-axis direction position detecting means 69: Z-axis direction position detecting means 71: Imaging means 72: Boundary part height position detecting means 75: Grinding wheel height position detecting means 76: Dressing means 761: Dressing board 8: Grinding unit 85: Grinding tool 852: Annular grinding wheel 83: Servo motor as grinding tool drive motor 10: Two-layer structure wafer Ha

11: Wafer 12 substrate 20: Control means

Claims (3)

A wafer chamfered portion removing apparatus for removing a wafer chamfered portion in a two-layer structure wafer in which a wafer surface having a chamfered portion formed on the outer periphery is bonded to a substrate,
A grinding tool having a chuck table having a holding surface for holding a workpiece, a chuck table driving motor for rotating the chuck table, and a grinding wheel for grinding the workpiece held on the holding surface of the chuck table And a grinding unit having a grinding tool drive motor for rotationally driving the grinding tool, and a Z-axis direction feeding means for moving the grinding unit and the chuck table relatively in the Z-axis direction perpendicular to the holding surface; Y-axis direction feed means for relatively moving the grinding unit and the chuck table in the Y-axis direction orthogonal to the Z-axis direction; Y-axis direction position detecting means for detecting the Y-axis direction position of the grinding tool; , Z-axis direction position detection means for detecting the position of the grinding tool in the Z-axis direction, and an image of the grinding area of the workpiece held on the holding surface of the chuck table Imaging means, boundary height position detecting means for detecting the height position of the boundary between the wafer and the substrate in the two-layer structure wafer held on the holding surface of the chuck table, and control means. ,
The control means operates the imaging means to detect a chamfered portion detecting step for detecting a chamfered portion to be removed from the wafer in a two-layer structure wafer in which the substrate side is held on the holding surface of the chuck table;
The boundary height position detecting means is operated and the chuck table driving motor is operated to rotate the chuck table so that the height position of the boundary between the chamfered portion to be removed from the wafer and the substrate is set every predetermined angle. A boundary height position detecting step to detect;
A grinding tool positioning step of positioning the grinding wheel of the grinding tool at a chamfer to be removed of the wafer in the two-layer structure wafer held on the chuck table by operating the Y-axis direction feeding means;
While operating the grinding tool drive motor to rotate the grinding tool, the chuck table drive motor is operated to rotate the chuck table, and the wafer in which the boundary height position detecting step has been performed is removed. A chamfered portion removing step for controlling the Z-axis direction feeding means based on height position information for each predetermined angle of the boundary portion between the power chamfered portion and the substrate is performed.
A chamfered portion removing apparatus for a wafer.   2. The wafer chamfered portion removing device according to claim 1, further comprising a grinding wheel height position detecting means for detecting a height position of a lower end of the grinding wheel of the grinding tool.   3. The wafer chamfered portion removing apparatus according to claim 1, further comprising dressing means for dressing a grinding surface of the grinding wheel of the grinding tool.

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