JP2014229875A - Processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing apparatus comprising a function capable of accurately detecting a contour of a wafer.SOLUTION: A processing apparatus is configured to process a wafer including a device area in which devices are formed over a plurality of areas sectioned by a plurality of scribe lines to be divided formed on a front surface in a lattice shape, and an outer peripheral surplus area which surrounds the device area and includes a chamfered part in an outer circumference. The processing apparatus comprises: a rotatable chuck table including a holding surface for holding the wafer; imaging means for imaging the outer circumferential part of the wafer held on the chuck table from an upper side; processing means for processing the outer circumferential part of the wafer held on the chuck table; X axis direction moving means for moving the chuck table in an X axis direction connecting an image region to be imaged by the imaging means and a process region to be processed by the processing means; and Y axis direction moving means for moving the chuck table and the processing means in a Y axis direction orthogonal to the X axis direction. The chuck table includes illumination means for irradiating light on the outer circumferential part of the wafer from a lower side to make the contour of the outer circumference clear when the wafer is held on the holding surface.

Description

  The present invention relates to a wafer such as a semiconductor wafer, more specifically, a device region in which a device is formed in a plurality of regions partitioned by a plurality of division lines formed in a lattice pattern on the surface, and surrounding the device region on the outer periphery. The present invention relates to a processing apparatus for processing a wafer including an outer peripheral surplus region having a chamfered portion.

  In the semiconductor device manufacturing process, a plurality of rectangular areas are defined by dividing lines formed in a lattice pattern on the surface of a substantially disc-shaped semiconductor wafer, and devices such as IC and LSI are formed in each rectangular area. To do. Individual devices are formed by dividing the semiconductor wafer on which a plurality of devices are formed in this manner along the division line. 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, the wafer is provided with an outer peripheral surplus area surrounding the device area, and a chamfered portion is formed on the outer periphery of the outer peripheral surplus area. Therefore, if the back surface of the wafer is ground and thinned to a predetermined thickness, the remaining chamfer is left. This is a so-called knife edge with a sharp portion, which is dangerous and has a problem that the wafer is cracked when the wafer is ground and the wafer is damaged.

  In order to solve such problems, a wafer processing method in which a chamfered portion of a wafer is cut and removed, and a back surface of the wafer from which the chamfered portion is removed is ground to a predetermined thickness is disclosed in Patent Document 1 below. It is disclosed.

  In addition, when grinding the back surface of the wafer, the region corresponding to the device region on the back surface of the wafer is ground to form the thickness of the device region to a predetermined finished thickness, and the outer peripheral portion on the back surface of the wafer is left. Patent Document 2 below discloses a wafer processing method in which a rigid wafer is formed by forming an annular reinforcing portion, and the annular reinforcing portion is cut when the wafer is divided into individual devices.

JP 2006-93333 A JP 2010-62375 A

  Thus, in the wafer processing methods described in Patent Document 1 and Patent Document 2, it is necessary to accurately detect the outline of the wafer, but since the chamfered portion is formed on the outer periphery of the wafer, the chamfering is performed. There is a problem that irregular reflection of light occurs in the portion and the contour of the wafer cannot be accurately detected.

  The present invention has been made in view of the above-mentioned facts, and a main technical problem thereof is to provide a processing apparatus having a function capable of accurately detecting the contour of a wafer.

In order to solve the above main technical problem, according to the present invention, a device region in which a device is formed in a plurality of regions defined by a plurality of division lines formed in a lattice pattern on the surface and the device region are surrounded. A processing device for processing a wafer provided with an outer peripheral surplus region having a chamfered portion on the outer periphery,
A rotatable chuck table having a holding surface for holding a wafer, imaging means for imaging the outer peripheral portion of the wafer held by the chuck table from above, and processing the outer peripheral portion of the wafer held by the chuck table Machining means to be applied, X-axis direction moving means for moving the chuck table in the X-axis direction connecting the imaging area by the imaging means and the machining area by the machining means, and the chuck table and the machining means to the X-axis direction Y-axis direction moving means for moving in the Y-axis direction orthogonal to
The chuck table is provided with illumination means for irradiating light from below to the outer peripheral portion of the wafer when the wafer is held on the holding surface to clarify the outer contour.
The processing apparatus characterized by this is provided.

  In the processing apparatus according to the present invention, a rotatable chuck table having a holding surface for holding a wafer is irradiated with light from below on the outer periphery of the wafer when the wafer is held on the holding surface. Therefore, the imaging means for imaging the outer peripheral portion of the wafer from the upper side can accurately grasp the outline of the outer peripheral edge of the wafer, and therefore the wafer has a chamfered portion on the outer periphery. However, the outer peripheral portion can be reliably cut.

The perspective view of the cutting device as a processing apparatus comprised according to this invention. Sectional drawing which shows 1st Embodiment of the illumination means provided in the chuck table with which the cutting apparatus shown in FIG. 1 is equipped. Sectional drawing which shows 2nd Embodiment of the illumination means provided in the chuck table with which the cutting apparatus shown in FIG. 1 is equipped. Sectional drawing which shows 3rd Embodiment of the illumination means provided in the chuck table with which the cutting apparatus shown in FIG. 1 is equipped. The block block diagram of the control means with which the cutting apparatus shown in FIG. 1 is equipped. The perspective view and enlarged sectional view of the semiconductor wafer as a wafer. Explanatory drawing of the protective tape sticking process which sticks a protective tape on the surface of the semiconductor wafer shown in FIG. Sectional drawing which shows the state which hold | maintained on the chuck table in the imaging area | region the semiconductor wafer in which the protective tape sticking process shown in FIG. 7 was implemented. Explanatory drawing of the chamfer part isolation | separation process implemented with the cutting device shown in FIG.

  Hereinafter, a preferred embodiment of a processing apparatus constructed according to the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 shows a perspective view of a cutting apparatus as a processing apparatus constructed according to the present invention.
The cutting device 1 shown in FIG. 1 includes a base 2. On the 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 base 2. The pair of guide rails 31 and 31 extend in parallel with each other along the X-axis direction indicated by an arrow X 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. 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.

  The chuck table 34 is formed of a metal material such as stainless steel, and includes a workpiece holding region 340 that holds a wafer as a workpiece as shown in FIG. A holding hole, which is the upper surface of the workpiece holding region 340, is formed with a fitting hole 341 having an open top, and an adsorption chuck 342 formed of a porous material such as porous ceramics is formed in the fitting hole 341. Mated. A suction passage 341a is opened at the bottom surface of the fitting hole 341, and the suction passage 341a communicates with suction means (not shown). The outer diameter of the workpiece holding region 340 is slightly smaller (3 to 5 mm) than the outer diameter of a wafer as a workpiece to be described later. In this way, the chuck table 34 having the workpiece holding region 340 is irradiated with light from below on the outer peripheral portion of the wafer when the wafer is held on the holding surface around the outer side of the workpiece holding region 340. Illumination means 343 is provided to clarify the outer contour. The illumination means 343 includes an annular light emitting means mounting portion 344 formed with a step around the outer periphery of the workpiece holding region 340, and a light emitting means 345 disposed on the annular light emitting means mounting portion 344. The light emitting means 345 is constituted by a transparent resin cover 346 disposed so as to be embedded. In the illustrated embodiment, the light emitting means 345 includes an LED 345a, and is connected to a lighting circuit (not shown). As the light emitting means 345, an organic EL 345b as shown in FIG. 3 or a phosphorescent material 345c made of zinc sulfide or aluminate strontium as shown in FIG. 4 can be used. The chuck table 34 configured in this manner is configured to place a wafer as a workpiece on the workpiece holding region 340 and suck and hold it by operating a suction means (not shown). Further, the chuck table 34 is rotated by a pulse motor 330 disposed in the cylindrical member 33 shown in FIG.

  1, the chuck table mechanism 3 in the illustrated embodiment moves the chuck table 34 along the pair of guide rails 31 and 31 in the X-axis direction indicated by the arrow X in FIG. X-axis direction moving means 36 is provided. The X-axis direction moving 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 moving 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. Accordingly, the X-axis direction moving 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 guide rails. It can move in the X-axis direction along 31 and 31.

  The cutting device 1 in the illustrated embodiment includes a gate-shaped 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. Yes. 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. Cutting means 5 is disposed on the upper surface 4a of the support frame 4 thus configured. The cutting means 5 includes a Y-axis direction moving base 51, a Z-axis direction moving base 52 and a spindle unit 6. The Y-axis direction moving base 51 is provided with guided grooves 511 and 511 which are fitted to a 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 51a of the Y-axis direction moving base 51 along a cutting feed direction (Z-axis direction) indicated by an arrow Z perpendicular to the holding surface of the chuck table 34. Is provided. The Y-axis direction moving base 51 configured in this way is moved in the Y-axis direction along the pair of guide rails 41 and 41 by the Y-axis direction moving means 53. The Y-axis direction moving 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 moving means 53 configured as described above is screwed into a female screw (not shown) formed on a protruding portion provided so that the male screw rod 531 protrudes from the rear surface of the Y-axis direction moving base 51. The Therefore, the Y-axis direction moving means 53 drives the pulse motor 533 to drive the male screw rod 531 in the normal direction or the reverse direction, thereby moving the Y-axis direction moving base 51 on 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. By fitting the guided grooves 521 and 521 to the pair of guide rails 512 and 512, the guided grooves 521 and 521 are configured to be movable along the pair of guide rails 512 and 512 in the Z-axis direction that is the cutting feed direction. The Z-axis direction moving base 52 configured as described above is moved in the Z-axis direction along the pair of guide rails 512 and 512 by the Z-axis direction moving means 54. The Z-axis direction moving 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 portion 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 moving means 54 is screwed into a female screw (not shown) formed on a protruding portion provided so that the male screw rod 541 protrudes from the rear surface of the Z-axis direction moving base 52. The Therefore, the Z-axis direction moving 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 spindle unit support member 55 for supporting the spindle unit 6 is mounted on the front surface 52 a of the Z-axis direction moving base 52. The spindle 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 spindle unit support member 55 configured as described above has an 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 spindle unit support member 55 is provided with four long holes 552a that are long in the X-axis direction. The fastening bolts are respectively inserted through the four long holes 552a. The unit housing 61 of the spindle unit 6 as a cutting means is attached to the lower surface of the support portion 552 by 554.

  As described above, the spindle unit 6 mounted on the lower surface of the support portion 552 constituting the spindle unit support member 55 is supported on the unit housing 61 mounted on the lower surface of the support portion 552 and rotatably supported by the unit housing 61. The rotary spindle 62 is formed, and a cutting blade 63 attached to the front end portion of the rotary spindle 62. The rotary spindle 62 is configured to be rotationally driven by a servo motor 64. In the spindle unit 6 configured as described above, the axis of the rotary spindle 62 on which the cutting blade 63 is mounted is disposed along the Y-axis direction orthogonal to the X-axis direction, and the rotary spindle 62 is the chuck table. It is important that they are arranged perpendicular to the Z-axis direction perpendicular to the holding surface which is the upper surface of 34.

  The cutting apparatus 1 in the illustrated embodiment has a workpiece held on a holding surface which is an upper surface of the chuck table 34 in a state where the chuck table 34 is positioned in the workpiece loading / unloading position and the imaging region shown in FIG. An image pickup means 7 is provided for picking up an image of the outer peripheral portion of the wafer, which is an object, from above. The image pickup means 7 includes an image pickup device (CCD) for picking up an image captured by the optical system, and sends the picked-up image signal to a control means described later.

  Further, the cutting device 1 in the illustrated embodiment includes a control means 8 shown in FIG. The control means 8 is constituted by a computer, and a central processing unit (CPU) 81 that performs arithmetic processing according to a control program, a read-only memory (ROM) 82 that stores a control program and the like, a control map, a calculation result, etc. described later. A readable / writable random access memory (RAM) 83, an input interface 84, and an output interface 85 are provided. A detection signal is input to the input interface 84 of the control means 8 from the imaging means 7 or the like. From the output interface 85 of the control means 8, a pulse motor 330 for rotating the chuck table 34, a pulse motor 363 for the X-axis direction moving means 36, a pulse motor 533 for the Y-axis direction moving means 53, and a Z-axis direction movement are provided. A control signal is output to the pulse motor 543 of the means 54, the servo motor 64 that rotationally drives the rotary spindle 62 on which the cutting blade 63 is mounted, and the like.

The cutting device 1 in the illustrated embodiment is configured as described above, and the operation thereof will be described below.
6A and 6B are perspective views of a semiconductor wafer as a wafer. A semiconductor wafer 10 shown in FIGS. 6A and 6B is made of, for example, a silicon wafer having a thickness of 700 μm and a diameter of 200 mm, and a plurality of streets 101 are formed in a lattice shape on the surface 10a. Devices 102 such as ICs and LSIs are formed in a plurality of areas partitioned by a plurality of streets 101. The semiconductor wafer 10 thus formed includes a device region 120 in which a plurality of devices 102 are formed, and an outer peripheral surplus region 130 that surrounds the device region 120. Further, in order to prevent the outer peripheral end portion of the outer peripheral surplus region 130 from being cracked or chipped due to an inadvertent impact, the cross-sectional shape is an arc from the front surface 10a to the rear surface 10b as shown in FIG. A chamfer 131 that forms a surface is formed.

  In order to form the semiconductor wafer 10 to a predetermined thickness (for example, 100 μm), first, in order to protect the device 102 formed on the surface 10a of the semiconductor wafer 10, as shown in FIGS. Thus, the protective tape T made of vinyl chloride or the like is attached to the surface 10a of the semiconductor wafer 10 (protective tape attaching step).

  If the above-described protective tape attaching step is performed, the protective tape T side of the semiconductor wafer 10 is placed on the chuck table 34 as shown in FIG. Then, by operating a suction means (not shown), the semiconductor wafer 10 is held on the chuck table 34 via the protective tape T (wafer holding process). Accordingly, the back surface 10b of the semiconductor wafer 10 held on the chuck table 34 is on the upper side. At this time, a part of the outer peripheral portion of the semiconductor wafer 10 protrudes from the workpiece holding region 340 and is positioned above the annular light emitting means mounting portion 344. In the state where the wafer holding process is performed, the outer peripheral portion of the semiconductor wafer 10 is positioned directly below the imaging means 7 as shown in FIG.

  When the wafer holding step described above is performed, the light emitting means 345 including the LED 345a is turned on to illuminate the outer peripheral portion of the semiconductor wafer 10 from below. Therefore, the imaging means 7 disposed immediately above the outer peripheral portion of the semiconductor wafer 10 can accurately capture the outline of the outer peripheral edge of the semiconductor wafer 10. Next, the image pickup means 7 is operated to pick up any three points on the outer periphery of the semiconductor wafer 10 and send an image pickup signal to the control means 8. The control means 8 obtains the coordinates of any three points on the outer periphery of the semiconductor wafer 10 based on the imaging signal sent from the imaging means 7, and the coordinates of the center position of the semiconductor wafer 10 based on the coordinates of these three points. Ask for. Then, the control means 8 calculates the positional deviation between the center position of the semiconductor wafer 10 and the rotation center of the chuck table 34 by the method described in the above-mentioned Japanese Patent Application Laid-Open No. 2006-93333, and the amount of this positional deviation is random access memory. (RAM) 83 to store (position shift calculation step).

  When the positional deviation calculation step is performed as described above, the chuck table 34 holding the semiconductor wafer 10 is moved to the cutting region. Then, the chamfered portion 131 and the device region in the outer peripheral surplus region 130 of the semiconductor wafer 10 held by the chuck table 34 as shown by a two-dot chain line in FIG. It is positioned immediately above a predetermined position (for example, a position 2 mm from the outer peripheral edge of the semiconductor wafer 10). Then, the servo motor 64 is operated to rotate the cutting blade 63 in the direction indicated by the arrow 63a as shown in FIG. 9 (a), and from the standby position indicated by the two-dot chain line, the pulse motor of the Z-axis direction moving means 54 543 is operated to cut and feed downward, and is positioned at a predetermined cutting and feeding position as indicated by a solid line. This cutting feed position is set to a position where the outer peripheral edge of the cutting blade 63 reaches the protective tape T.

  Next, as described above, the pulse motor 330 is operated while the cutting blade 63 is rotated in the direction indicated by the arrow 63a, and the chuck table 34 is moved in the direction indicated by the arrow 34a in FIG. For example, it is rotated at 1 degree / second (chamfered portion separation step). In this chamfered portion separation step, the control means 8 uses the positional deviation amount stored in the random access memory (RAM) 83 and the rotation angle of the chuck table 34 as in the method described in Japanese Patent Laid-Open No. 2006-93333. Based on (according to the number of drive pulses applied to the pulse motor 330), the pulse motor 533 of the Y-axis direction moving means 53 is controlled to move the spindle unit 6 in the Y-axis direction. Then, as the chuck table 34 rotates once, the semiconductor wafer 10 is formed along a predetermined position between the chamfered portion 131 and the device region 120 in the outer peripheral surplus region 130 as shown in FIG. 9B. The chamfered portion 131 is separated by being cut by the annular cutting groove 140. In this chamfered portion separation step, as described above, the spindle unit 6 is moved in the Y-axis direction in accordance with the positional deviation between the center position of the semiconductor wafer 10 and the rotation center of the chuck table 34. The portion is cut in the circumferential direction at substantially the same distance from the center position of the semiconductor wafer 10.

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 illustrated embodiment, a positional deviation between the center position of the semiconductor wafer 10 and the rotation center of the chuck table 34 is calculated, and the Y-axis direction moving means is calculated based on the positional deviation amount and the rotation angle of the chuck table 34. Although an example in which the spindle motor 6 is moved in the Y-axis direction by controlling the pulse motor 533 of 53 is shown, the chuck table 34 is moved 1 while the outer periphery of the semiconductor wafer 10 held on the chuck table 34 is imaged by the imaging means 7. By rotating, the amount of displacement in the Y-axis direction from the rotation center of the chuck table 34 at the outer peripheral edge of the semiconductor wafer 10 is obtained, and the pulse motor 533 of the Y-axis direction moving means 53 is moved based on the amount of displacement in the Y-axis direction. The spindle unit 6 may be controlled to move in the Y-axis direction.
Moreover, although the example which applied this invention to the cutting device was shown in embodiment of illustration shown above, this invention is applicable to other processing apparatuses, such as a laser processing apparatus.

1: Cutting device 2: Base 3: Chuck table mechanism 32: Chuck table support base 34: Chuck table 36: X-axis direction moving means 4: Support frame 5: Cutting means 51: Y-axis direction moving base 52: Z Axial direction moving base 53: Y axis direction moving means 54: Z axis direction moving means 55: Spindle unit support member 6: Spindle unit 61: Unit housing 62: Rotating spindle 63: Cutting blade 64: Servo motor 7: Imaging means 8 : Control means 10: Semiconductor wafer

Claims (1)

A wafer comprising a device region in which devices are formed in a plurality of regions partitioned by a plurality of division lines formed in a lattice shape on the surface, and an outer peripheral surplus region surrounding the device region and having a chamfered portion on the outer periphery. A processing device for processing,
A rotatable chuck table having a holding surface for holding a wafer, imaging means for imaging the outer peripheral portion of the wafer held by the chuck table from above, and processing the outer peripheral portion of the wafer held by the chuck table Machining means to be applied, X-axis direction moving means for moving the chuck table in the X-axis direction connecting the imaging area by the imaging means and the machining area by the machining means, and the chuck table and the machining means to the X-axis direction Y-axis direction moving means for moving in the Y-axis direction orthogonal to
The chuck table is provided with illumination means for irradiating light from below to the outer peripheral portion of the wafer when the wafer is held on the holding surface to clarify the outer contour.
A processing apparatus characterized by that.

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