JP2023112771A - Processing device - Google Patents

Abstract

To provide an optical system which can be used for holding tables with different diameters.SOLUTION: A processing device which is used when calculating the center position of one surface of a disc-like wafer and performs prescribed processing on the outer peripheral part of the wafer comprises: a holding unit; a processing unit; and an imaging unit which is arranged above the holding unit and images the outer peripheral part of the wafer. The imaging unit comprises: a camera part; a light-emitting unit which includes a light source; and at least three reflecting units which can radiate light from the light source upward. The processing device images at least three spots of the outer peripheral part of the wafer with the imaging unit by sequentially irradiating the outer peripheral part of the wafer that has the larger diameter than the holding table and protrudes to the outer side in the radial direction of the holding table when being suction-held by the holding table with light from the light source from each reflecting unit by adjusting the position of each reflecting unit in the imaging unit.SELECTED DRAWING: Figure 1

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing apparatus that is used to calculate the center position of one surface of a disk-shaped wafer and performs predetermined processing on the outer peripheral portion of the wafer.

In a disk-shaped wafer having a device region in which a plurality of devices are formed and an outer peripheral surplus region surrounding the device region on the front side, a region on the back side corresponding to the device region is ground to form a circular recess. In addition, a processing method is known in which a ring-shaped reinforcing portion is left in a region corresponding to the peripheral surplus region, and then the wafer is divided into device units (see, for example, Patent Document 1).

When dividing the wafer into device units according to the processing method, it is usually necessary to first remove the ring-shaped reinforcing portion. Therefore, there has been proposed a processing apparatus that specifies the center position of the surface of the wafer and then accurately cuts and removes the ring-shaped reinforcing portion based on this center position (see, for example, Patent Documents 2 and 3). .

The processing apparatus described in Patent Document 3 uses a holding table having a smaller diameter than the wafer and having a truncated cone closer to the bottom than the holding surface in order to specify the center position of the surface of the wafer. The truncated cone is inclined at 45 degrees with respect to the horizontal and has an annular inclined surface on its side that functions as a mirror surface.

A light source such as an LED (Light Emitting Diode) is provided on the side of the truncated cone. A camera capable of capturing an image of reflected light is provided above the inclined surface, and the light emitted from the light source is reflected upward by the inclined surface and captured by the camera.

In order to calculate the central position of the surface of the wafer using this truncated cone, first, the concave portion corresponding to the device region formed by grinding is fitted into the holding table, and the wafer is held by suction on the holding table. At this time, the outer peripheral portion of the wafer protrudes outside the holding table.

Next, the side surface of the truncated cone is irradiated with light from the side, the outer peripheral portion of the wafer is irradiated with the reflected light from the inclined surface, and the outer peripheral portion is imaged using a camera. In particular, by rotating the chuck table, three different locations on the outer periphery of the wafer are captured by the camera.

Since the center position (coordinates) of the holding surface of the holding table is known, the center position (coordinates) of the surface of the wafer ( center coordinates) can be calculated.

However, wafers have various outer diameters such as 6 inches (about 150 mm), 8 inches (about 200 mm), and 12 inches (about 300 mm). varies depending on the diameter of the wafer.

Japanese Unexamined Patent Application Publication No. 2007-19461 JP 2014-60224 A Japanese Patent Application Laid-Open No. 2020-43186

Therefore, in order to suck and hold recesses of wafers having various diameters, a holding table having a diameter corresponding to the diameter of the wafer is required. Therefore, in an optical system using a truncated cone, different sized truncated cones are required in accordance with the outer diameter of the holding table, and there is a problem in that replacement of the truncated cone is required accordingly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides an optical system that can irradiate the outer periphery of a wafer sucked and held by a holding table and that can be used for holding tables with different diameters. intended to

According to one aspect of the present invention, there is provided a processing apparatus that is used to calculate the center position of one surface of a disk-shaped wafer and performs predetermined processing on the outer peripheral portion of the wafer, the processing device holding the wafer a holding unit for processing the wafer, a processing unit for processing the wafer, and an imaging unit for imaging the outer peripheral portion of the wafer held by the holding unit, the holding unit sucking and holding the wafer. A plate-like holding table, a rotary shaft connected to the holding table for rotating the holding table, and a drive unit for rotating the rotary shaft, the imaging unit being connected to the camera unit. a light-emitting unit provided below the camera section and including a light source; and a light-emitting unit, each fixed to the rotating shaft and arranged on the outer peripheral portion of the holding table so as to be separated from each other along the circumferential direction of the holding table. and at least three reflecting units each having a pair of opposing inclined surfaces and capable of upwardly irradiating light from the light source via the pair of inclined surfaces, wherein each of the reflecting units in the imaging unit By adjusting the position of the wafer, the outer peripheral portion of the wafer, which has a diameter larger than that of the holding table and protrudes outside the holding table in the radial direction when the wafer is held by suction by the holding table, is adjusted to the light source. A processing apparatus is provided in which light from a wafer is sequentially irradiated from each reflection unit, and at least three locations on the outer periphery of the wafer are imaged by the imaging unit.

Preferably, when a first holding table having a first diameter is used as the holding table in the holding unit, the at least three reflecting units are arranged to be held by suction on the first holding table. At least an outer peripheral portion of the first wafer protruding outside the first holding table in the radial direction and having a diameter larger than the first diameter can be irradiated with light from the light source. When three first reflecting units and a second holding table having a second diameter larger than the first diameter are used as the holding table in the holding unit instead of the first holding table, At the outer peripheral portion of the second wafer, which protrudes radially outward of the second holding table and has a larger diameter than the second diameter when held by suction on the second holding table. and at least three second reflection units each capable of irradiating light from the light source.

Preferably, the holding unit further has an annular auxiliary table provided on the outer circumference of the holding table, and the auxiliary table directs the light reflected by each reflection unit to the outer circumference of the wafer. Includes through holes for illumination.

Moreover, preferably, the pair of inclined surfaces of each reflecting unit is arranged with It includes a first mirror surface and a second mirror surface inclined by 45 degrees.

The holding units of the processing apparatus according to one aspect of the present invention are fixed to the rotating shaft of the holding table, and arranged on the outer peripheral portion of the holding table so as to be separated from each other along the circumferential direction of the holding table. It has three reflection units. Each reflection unit has a pair of inclined surfaces facing each other, and can irradiate upward the light incident on each reflection unit from the light source via the pair of inclined surfaces.

An imaging unit captures an image of the outer peripheral portion of the wafer held by the holding unit. For example, when a first holding table having a first diameter is attached to the holding unit and the first holding table sucks and holds the first wafer, three reflecting units are used to hold the first wafer. The coordinates of three points on the edge of the first wafer are specified by imaging the outer periphery of the wafer.

On the other hand, when a holding table having a diameter larger than the first diameter is attached to the holding unit and a wafer having a larger diameter than the first wafer is sucked and held by the holding table, the reflection unit is used. Identify the coordinates of three points on the edge of a large diameter wafer without

In this way, when holding tables of different sizes are used, the coordinates of the outer peripheral edges of wafers of different diameters can be specified simply by selecting whether or not to use at least three reflection units. Therefore, it is possible to provide an optical system that can be used for holding tables with different diameters.

Furthermore, compared to the case where a dedicated truncated cone corresponding to the diameter of the holding table is mounted for each holding table of different size, it is possible to eliminate the labor required to replace the truncated cone.

1 is a perspective view of a laser processing device; FIG. FIG. 2A is a perspective view of the front side of the wafer unit, and FIG. 2B is a perspective view of the back side of the wafer. It is an expansion perspective view of a holding unit. It is a partial cross section side view of a holding unit. It is a partial cross-sectional side view which shows a mode that the outer peripheral part of a wafer is imaged. It is a partial cross-sectional side view which shows a mode that the outer peripheral part of a large diameter wafer is imaged. 7A is a top view of a holding unit or the like to which a chuck table having a first diameter is mounted, and FIG. 7B is a top view of the holding unit or the like to which a chuck table having a second diameter is mounted. It is a diagram. It is a partial cross-sectional side view which shows the reflection unit which concerns on 3rd Embodiment. It is an enlarged view of a holding unit according to a modification. It is a partial cross-sectional side view which shows a mode that the outer peripheral part of a wafer is imaged. It is a partial cross-sectional side view which shows a mode that the outer peripheral part of a large diameter wafer is imaged.

An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view showing a configuration example of a laser processing device (processing device) 2. As shown in FIG. The laser processing device 2 includes a base 4 that supports each structure.

The base 4 includes a rectangular parallelepiped base 6 and a wall 8 extending upward at the rear end of the base 6 . A disc-shaped chuck table (first holding table) 10 is arranged above the base 6 . The chuck table 10 sucks and holds a disk-shaped wafer (first wafer) 11 to be processed.

Here, the wafer 11 will be described with reference to FIGS. 2(A) and 2(B). Wafer 11 has a single crystal substrate formed of a semiconductor material such as silicon. However, the single-crystal substrate is not limited to silicon, and may be formed of compound semiconductors such as silicon carbide (SiC), gallium nitride (GaN), or other materials.

As shown in FIG. 2A, a plurality of dividing lines 13 are set in a lattice pattern on the front surface (one surface) 11a of the wafer 11. As shown in FIG. A device 15 is formed in each rectangular area partitioned by a plurality of planned division lines 13 .

The devices 15 are, for example, ICs (Integrated Circuits), MEMS (Micro Electro Mechanical Systems), LEDs (Light Emitting Diodes), etc., but there are no particular restrictions on the type, size, number, arrangement, etc. of the devices 15 .

In the radial direction of the wafer 11, there is an annular peripheral surplus region 19 outside the device region 17 in which the plurality of devices 15 are formed. The peripheral surplus region 19 is a substantially flat region where the device 15 is not formed.

In FIG. 2A, the boundary 17a between the device region 17 and the peripheral surplus region 19 is indicated by a dashed line for convenience, but the boundary 17a is not shown on the actual wafer 11. As shown in FIG. A notch 11c indicating the crystal orientation of the single crystal substrate is formed in the outer peripheral portion of the wafer 11. As shown in FIG.

As shown in FIG. 2B, by grinding a circular region corresponding to the device region 17 on the back surface 11b side of the wafer 11, a circular concave portion 21 is formed on the back surface 11b side. For example, wafer 11 in device region 17 is thinned to a thickness of approximately 50 μm.

An annular projection 23 is formed outside the circular recess 21 so as to surround the circular recess 21 . The annular convex portion 23 is an area that remains without being ground when the circular concave portion 21 is formed, and is an annular area corresponding to the peripheral surplus area 19 .

The diameter of the wafer 11 is, for example, 8 inches (approximately 200 mm). The thickness of the annular projection 23 has the thickness of the wafer 11 before grinding, for example, about 725 μm. Further, the width of the annular protrusion 23 in the radial direction of the wafer 11 is, for example, approximately 3.0 mm.

The annular convex portion 23 functions as a reinforcing portion for the wafer 11 in which the circular concave portion 21 is formed. By providing the annular protrusion 23, it is possible to prevent the wafer 11 from being damaged during transportation, compared to the case where the back surface 11b side is uniformly thinned without providing the annular protrusion 23. FIG.

After forming the circular concave portion 21 on the back surface 11 b side, a circular tape 25 having a diameter larger than that of the wafer 11 is attached to the back surface 11 b side of the wafer 11 . The tape 25 is made of a resin that is substantially transparent at least to light in the visible light band.

The tape 25 has a laminated structure of, for example, an adhesive layer (glue layer) made of adhesive resin such as ultraviolet curable resin and a base layer made of resin. The rear surface 11b side of the wafer 11 is attached to the central portion of the tape 25 so as to follow the shape of the circular concave portion 21 .

One surface of an annular frame 27 made of metal is attached to the outer peripheral portion of the tape 25 . In this manner, a wafer unit 29 is formed in which the wafer 11 is supported on the annular frame 27 via the tape 25. As shown in FIG.

2A is a perspective view of the front surface 11a side of the wafer unit 29, and FIG. 2B is a perspective view of the back surface 11b side of the wafer 11 with the tape 25 and the annular frame 27 omitted. The wafer unit 29 is held by suction on the chuck table 10 via the tape 25 .

3 is an enlarged perspective view of the holding unit 12 of the first embodiment including the chuck table 10, and FIG. 4 is a partial cross-sectional side view of the holding unit 12. FIG. As shown in FIG. 4, the chuck table 10 has a disk-shaped frame 14a made of non-porous ceramics.

A disk-shaped concave portion is formed on the upper surface side of the frame 14a. A porous plate 14b made of porous ceramics is fixed to the recess. Grooves and holes are formed in the bottom of the recess for transmitting negative pressure to the porous plate 14b.

When negative pressure is applied from a suction source 16 such as an ejector, negative pressure is generated on the upper surface of the porous plate 14b through the grooves and holes of the frame 14a. The upper surfaces of the frame 14a and the porous plate 14b function as a holding surface 10a for holding the wafer unit 29 by suction.

The wafer 11 is placed on the chuck table 10 so that the circular recess 21 fits over the chuck table 10 including the holding surface 10a via the tape 25 . A lower portion of the chuck table 10 is detachably fixed to a disk-shaped table base 18 .

Chuck table 10 having an appropriate size is selected according to the size of wafer 11 to be held by suction (more specifically, the diameter of circular recess 21 of wafer 11), and is mounted on table base 18. FIG. An upper portion of a cylindrical rotating shaft 20 is connected to the lower portion of the table base 18 .

A part of the rotating shaft 20 corresponds to the rotor of an electrically driven motor, and is supported by an X-axis direction moving plate 40 to be described later via bearings (not shown). A cylindrical driving portion 22 for rotating the rotating shaft 20 is provided around the rotating shaft 20 .

The drive part 22 corresponds to the stator of an electrically driven motor. The rotating shaft 20 and the driving section 22 constitute a DC motor. However, the rotating shaft 20 and the drive unit 22 may be other types of motors such as AC motors.

When power is supplied to the drive unit 22 , the chuck table 10 , which is connected to the rotating shaft 20 via the table base 18 , rotates around the center 20 a of the rotating shaft 20 . The drive unit 22 is provided with a rotation angle sensor (not shown) such as a rotary encoder for detecting the rotation angle of the chuck table 10 .

A plurality of clamp units 24 each clamping an annular frame 27 are arranged along the circumferential direction of the chuck table 10 at approximately equal intervals on the outer peripheral portion of the chuck table 10 . A proximal end of each clamp unit 24 is fixed to the table base 18 .

The chuck table 10 , the table base 18 , the rotating shaft 20 , the drive section 22 , the four clamp units 24 and the like constitute the holding unit 12 . The chuck table 10 is appropriately exchanged according to the diameter of the wafer 11 to be held by suction.

Four reflection units (first reflection units) 26 are arranged on the outer periphery of the table base 18 at substantially equal intervals along the circumferential direction of the chuck table 10 . The base end of each reflection unit 26 is fixed to the rotating shaft 20 via the table base 18 at a position different from that of the clamp unit 24 .

Here, with reference to FIG. 5, the reflection unit 26 will be described in detail. The reflecting unit 26 has a metal arm portion 28 whose longitudinal direction 28 a protrudes along the radial direction of the table base 18 . Each arm portion 28 is arranged on the outer peripheral portion of the chuck table 10 so as to protrude outward from the outer peripheral portion of the chuck table 10 .

A metal first reflection block 30 having a greater thickness in the Z-axis direction than the arm portion 28 is provided at the tip portion of the arm portion 28 in the longitudinal direction 28a. The outer side surface of the first reflecting block 30 in the longitudinal direction 28a is a vertical plane (a plane perpendicular to the longitudinal direction 28a) 30a perpendicular to the longitudinal direction 28a.

On the other hand, the inner side surface of the first reflecting block 30 in the longitudinal direction 28a is a plane (inclined surface 30b) that is inclined by a predetermined angle with respect to the vertical plane 30a. The inclined surface 30b of this embodiment is inclined at 45 degrees with respect to the vertical plane 30a so that the lower end is located outside the upper end in the longitudinal direction 28a.

The inclined surface 30b includes a first mirror surface 30c formed by mirror finishing. Note that the first mirror surface 30c may be provided by fixing a mirror to the inclined surface 30b instead of mirror finishing.

A base end portion of the arm portion 28 is formed with a through-hole 28b in the shape of an inverted square pyramid. At least part of the through-hole 28b is positioned outside the outer periphery of the holding surface 10a in the longitudinal direction 28a and directly below the outer peripheral portion 11d of the wafer 11 sucked and held by the holding surface 10a.

A second reflecting block 34 made of metal having a greater thickness in the Z-axis direction than the arm portion 28 is provided on the lower surface side of the proximal end portion of the arm portion 28 . An opening 34a is formed at the tip of the second reflection block 34 in the longitudinal direction 28a.

On the table base 18 side of the opening 34a of the second reflection block 34, there is a flat surface (inclined surface 34b) that is positioned directly below the through hole 28b and that is arranged to face the inclined surface 30b in the longitudinal direction 28a. is provided.

The inclined surface 34b is inclined in the same direction as the inclined surface 30b by a predetermined angle with respect to the vertical plane 30a. The inclined surface 34b of this embodiment is inclined 45 degrees in the same direction as the inclined surface 30b with respect to the vertical plane 30a.

In addition, the inclined surface 34b includes a second mirror surface 34c formed by mirror finishing. Note that the second mirror surface 34c may be provided by fixing a mirror to the inclined surface 34b instead of mirror finishing.

When the rotary shaft 20 is rotated, the chuck table 10, table base 18, arm portion 28, etc. are rotated together. A light-emitting unit 32 including a light source 32a such as an LED is provided directly below an area corresponding to one portion of an annular area formed by the trajectory of the inclined surface 30b of the first reflection block 30. As shown in FIG.

The light 32b emitted from the light emitting unit 32 sequentially passes through the first mirror surface 30c and the second mirror surface 34c (that is, the pair of inclined surfaces 30b and 34b) and the through hole 28b, and is emitted upward from the through hole 28b. be. This light 32b is used when the camera section 64, which will be described later, takes an image of the outer peripheral portion 11d (particularly, the outer peripheral edge 11e) of the wafer 11 sucked and held by the holding surface 10a.

In addition, in this embodiment, the case where the holding unit 12 is provided with the four reflection units 26 has been described. However, in order to image at least three locations on the outer peripheral portion 11 d of the wafer 11 , at least three reflection units 26 should be provided in the holding unit 12 .

The four (at least three) reflection units 26, the light emission unit 32, the camera section 64, etc. constitute an imaging unit 36 (that is, an optical system). Here, referring back to FIG. 1, other components of the laser processing apparatus 2 will be described.

The drive unit 22 described above is supported by a rectangular X-axis moving plate 40 . The light emitting unit 32 described above is fixed to one of the four corners of the X-axis moving plate 40 . The X-axis direction moving plate 40 is slidably supported by a pair of X-axis guide rails 42 arranged substantially parallel to the X-axis direction.

A nut portion (not shown) is provided on the lower surface side of the X-axis direction moving plate 40, and this nut portion has a screw shaft 44 having a longitudinal portion arranged along the X-axis direction and a ball (not shown). ) are rotatably connected. A drive source 46 such as a stepping motor is connected to one end of the screw shaft 44 .

When the screw shaft 44 is rotated by the drive source 46, the X-axis direction moving plate 40 moves along the X-axis direction. The X-axis direction moving plate 40, the pair of X-axis guide rails 42, the nut portion, the screw shaft 44, the driving source 46, and the like constitute a ball screw type X-axis direction moving unit 48. As shown in FIG.

A pair of X-axis guide rails 42 are fixed to the upper surface of the Y-axis movement plate 50 . The Y-axis movement plate 50 is slidably supported by a pair of Y-axis guide rails 52 fixed to the upper surface of the base 6 substantially parallel to the Y-axis direction.

A nut portion (not shown) is provided on the lower surface side of the Y-axis direction moving plate 50, and this nut portion has a screw shaft 54 having a longitudinal portion arranged along the Y-axis direction and a ball (not shown). ) are rotatably connected. A drive source 56 such as a stepping motor is connected to one end of the screw shaft 54 .

When the screw shaft 54 is rotated by the drive source 56, the Y-axis direction moving plate 50 moves along the Y-axis direction. The Y-axis movement plate 50 , the pair of Y-axis guide rails 52 , the nut portion, the screw shaft 54 , the drive source 56 and the like constitute a ball screw type Y-axis movement unit 58 .

A base end portion of a cantilever-like arm 60 is fixed to the front side surface of the wall portion 8 so as to protrude upward from the holding unit 12 . A part of a laser processing unit (processing unit) 62 for processing the wafer 11 or the like is provided on the arm 60 .

The laser processing unit 62 includes a laser oscillator (not shown) containing a rod-shaped laser medium made of Nd:YAG, Nd: _YVO4 , or the like. A pulsed laser beam emitted from a laser oscillator is irradiated toward the holding surface 10a through a substantially cylindrical condenser 62a arranged at the tip of the arm 60 and above the holding unit 12. .

The laser beam emitted from the condenser 62a has a wavelength (for example, 355 nm) that is absorbed by the wafer 11 . Rotating the chuck table 10 with the focal point of the laser beam condensed by the concentrator 62a positioned at the boundary 17a allows the annular protrusion 23 to be separated from the wafer 11 by ablation.

In this manner, the laser processing unit 62 is used when laser processing (predetermined processing) is performed on the outer peripheral portion 11 d of the wafer 11 . The arm 60 is provided with a camera section 64 in addition to the laser processing unit 62 .

The camera section 64 includes a substantially cylindrical head section 64 a arranged at the distal end of the arm 60 and above the holding unit 12 . A condensing lens (not shown) and the like are provided in the head portion 64a. The light emitting unit 32 described above is provided below the head portion 64a.

The head part 64a can take in the light 32b reflected by the reflecting unit 26 after being emitted from the light emitting unit 32, or directly take in the light 32b emitted from the light emitting unit 32 without passing through the reflecting unit 26. can.

The camera unit 64 includes an imaging device (not shown) such as a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor, a CCD (Charge-Coupled Device) image sensor, or the like. The light 32b taken in from the head portion 64a is photoelectrically converted by the imaging element and stored as image information in a storage device (not shown) of the laser processing apparatus 2. FIG.

The image information is displayed as an image on a touch panel 68 provided on the front surface of the housing 66 of the laser processing apparatus 2, for example. The touch panel 68 functions as a display device for displaying images to the operator, and also functions as an input device for the operator to perform predetermined operations and inputs.

Operations of the holding unit 12 , the suction source 16 , the imaging unit 36 , the X-axis direction moving unit 48 , the Y-axis direction moving unit 58 , the laser processing unit 62 , the touch panel 68 and the like are controlled by the control unit 70 .

The control unit 70 includes, for example, a processor (processing device) represented by a CPU (Central Processing Unit), a main memory such as a DRAM (Dynamic Random Access Memory), an SRAM (Static Random Access Memory), and a ROM (Read Only Memory). It consists of a computer that includes devices and secondary storage devices such as flash memory, hard disk drives, solid state drives, and the like.

Software including a predetermined program is stored in the auxiliary storage device. The functions of the control unit 70 are realized by operating the processor and the like according to this software.

Next, referring to FIG. 5, a procedure for calculating the center position 11a ₁ (see FIG. 2A) of the front surface 11a of the wafer 11 will be described. FIG. 5 is a partial cross-sectional side view showing how the outer peripheral portion 11d of the wafer 11 is imaged.

A chuck table 10 having a first diameter 10b smaller than the diameter of the wafer 11 and corresponding to the diameter of the circular recess 21 of the wafer 11 is used to hold the wafer 11 on the back surface 11b side by suction.

First, the circular concave portion 21 of the wafer 11 is fitted onto the upper portion of the chuck table 10 via the tape 25 . Next, the annular frame 27 (not shown in FIG. 5) is clamped by the clamp unit 24, and the back surface 11b side of the circular concave portion 21 is sucked and held by the holding surface 10a by negative pressure.

Since the wafer 11 has a diameter larger than the first diameter 10b, the outer peripheral portion 11d of the wafer 11 held by suction on the holding surface 10a protrudes outside the chuck table 10 in the radial direction. In this manner, the holding unit 12 holds the wafer 11 .

After that, the X-axis direction moving unit 48 , the Y-axis direction moving unit 58 and the driving section 22 are operated to adjust the position of one reflecting unit 26 with respect to the head section 64 a and the light emitting unit 32 .

Specifically, the head portion 64a is positioned directly above the through hole 28b of one reflecting unit 26, and the light emitting unit 32 is positioned directly below the inclined surface 30b of the one reflecting unit 26. The rotation angle of one reflection unit 26 and the positions of the X-axis moving plate 40 and the Y-axis moving plate 50 are adjusted.

Then, when the outer peripheral portion 11d of the wafer 11 is irradiated with the light 32b from the first reflecting unit 26 and the outer peripheral portion 11d is imaged by the camera section 64, the area blocked by the wafer 11 and the area blocked by the wafer 11 are captured. A first image is obtained that includes the areas that were absent.

Next, the rotating shaft 20 is rotated by approximately 90 degrees, and the second reflection unit 26 irradiates the outer peripheral portion 11d of the wafer 11 with the light 32b, and the camera portion 64 takes an image of the outer peripheral portion 11d. 2 images are obtained.

Next, the rotating shaft 20 is further rotated by approximately 90 degrees, and the outer peripheral portion 11d of the wafer 11 is irradiated with the light 32b from the third reflecting unit 26, and the outer peripheral portion 11d is imaged by the camera section 64. A third image is obtained.

As described above, in this embodiment, after sequentially irradiating the light 32b from each reflection unit 26 and imaging three different locations on the outer peripheral portion 11d of the wafer 11, the first program stored in the control unit 70 is used to detect the edge of the wafer 11. Predetermined image processing such as detection is performed.

For example, the first program performs edge detection after performing binarization processing on the first to third images, thereby corresponding to the outer peripheral edge 11e in each of the first to third images. Coordinates are obtained one by one, that is, three points in total.

The coordinates of the three points are respectively defined with the center position (coordinates) 10c (see FIG. 4) of the holding surface 10a as the origin. Note that the center position 10c of the holding surface 10a and the center position _11a1 of the front surface 11a of the wafer 11 usually do not completely match and are deviated.

By using a known method described in Patent Document 3, etc., the center position 11a1 of the surface 11a can be _calculated based on the center position 10c of the holding surface 10a and the coordinates of the three points corresponding to the outer peripheral edge 11e. .

A second program is stored in the control unit 70 for calculating the center position _11a1 of the surface 11a. In the above description, an example of imaging three locations on the outer peripheral portion 11d has been described, but at least three locations on the outer peripheral portion 11d may be imaged.

For example, by capturing images at four or more locations and selectively using appropriate images excluding images that could not be captured for some reason, the coordinates of three points corresponding to the outer peripheral edge 11e and the center position 11a ₁ can be obtained. can also be calculated.

The imaging units 36 other than the four reflecting units 26 are also used when imaging the outer peripheral portion 31 d of the wafer (second wafer) 31 having a diameter larger than that of the wafer 11 . FIG. 6 is a partial cross-sectional side view showing how the outer peripheral portion 31d of the wafer 31 having a diameter larger than that of the wafer 11 is imaged.

The diameter of the wafer 31 is, for example, 12 inches (about 300 mm), which is larger than the diameter of the wafer 11 (8 inches). As with the wafer 11, the wafer 31 also has a circular recess 41 formed on the rear surface 31b side.

When sucking and holding the back surface 31b side of the wafer 31, instead of the chuck table 10, a chuck table (second holding table) 80 having a second diameter 80b corresponding to the diameter of the circular concave portion 41 of the wafer 31 is used. , is mounted on the table base 18 . The second diameter 80b is larger than the first diameter 10b of the chuck table 10. As shown in FIG.

The chuck table 80 , the table base 18 , the rotating shaft 20 , the drive section 22 , the four clamp units 24 and the like also constitute the holding unit 12 . Since the structure of the chuck table 80 is substantially the same as that of the chuck table 10, detailed description thereof will be omitted.

In order to image the outer peripheral portion 31 d of the wafer 31 , first, the circular concave portion 41 of the wafer 31 is fitted to the upper portion of the chuck table 80 with the tape 25 interposed therebetween. Next, the annular frame 27 (not shown in FIG. 6) is clamped by the clamp unit 24, and the back surface 31b side of the circular concave portion 41 is sucked and held by the holding surface 80a by negative pressure.

Since the wafer 31 has a diameter larger than the second diameter 80b, the outer peripheral portion 31d of the wafer 31 protrudes radially outward of the chuck table 80 when it is held by suction on the holding surface 80a.

After holding the wafer 31 by the holding unit 12, the X-axis direction moving unit 48 and the Y-axis direction moving unit 58 are operated to dispose the light emitting unit 32 directly below the head portion 64a. Then, by imaging the outer peripheral portion 31 d with the camera section 64 , a fourth image including the area blocked by the wafer 31 and the area not blocked by the wafer 31 is obtained.

As shown in FIG. 6 , when imaging the outer peripheral portion 31 d of the wafer 31 , the outer peripheral portion 31 d of the wafer 31 is directly irradiated with the light 32 b without using the reflection unit 26 . Next, the rotary shaft 20 is rotated by approximately 90 degrees to directly irradiate the outer peripheral portion 31d with the light 32b, and the camera section 64 captures an image of the outer peripheral portion 31d to obtain a fifth image.

Next, the rotating shaft 20 is further rotated by approximately 90 degrees to directly irradiate the outer peripheral portion 31d of the wafer 31 with the light 32b, and the camera section 64 captures an image of the outer peripheral portion 31d to obtain a sixth image. Of course, four or more locations on the outer peripheral portion 31d may be imaged.

In this way, the outer peripheral portion 31d of the wafer 31 is sequentially irradiated with the light 32b without passing through each reflection unit 26, and three different locations on the outer peripheral portion 31d are imaged. (not shown) is calculated.

As described above, in this embodiment, when chuck tables 10 and 80 having different sizes are used, the outer peripheral edges 11e of wafers 11 and 31 having different diameters can be detected simply by selecting whether or not to use at least three reflection units 26 . , 31e can be identified respectively.

Therefore, it is possible to provide an optical system that can be used for chuck tables 10 and 80 having different diameters. Furthermore, compared to the case where a dedicated truncated cone corresponding to the diameter of the chuck tables 10, 80 is attached to each of the chuck tables 10, 80 of different sizes, it is possible to reduce the labor required to replace the truncated cone.

In the first embodiment, when the chuck table 10 is viewed from above, the through hole 28b is located inside the light emitting unit 32 in the radial direction of the table base 18. As shown in FIG.

However, when the inclined surfaces 30b and 34b are inclined 45 degrees in the opposite direction to the example of FIG. , the light emitting unit 32 is arranged.

(Second Embodiment) Next, a second embodiment will be described with reference to FIGS. 7(A) and 7(B). FIG. 7A is a top view of the holding unit 12 and the like on which the chuck table 10 having the first diameter 10b is mounted.

In FIG. 7A, the outer peripheral edge 11e of the wafer 11 whose rear surface 11b side is suction-held by the holding surface 10a is indicated by a dashed line. As shown in FIG. 7A, the outer peripheral edge 11e is located directly above the through holes 28b of the four reflecting units 26. As shown in FIG.

In the example shown in FIG. 7A, along the circumferential direction of the table base 18, four clamp units 24 are arranged at substantially equal intervals, four reflection units 26 are arranged at substantially equal intervals, and four clamp units 26 are arranged at substantially equal intervals. Reflection units (second reflection units) 86 are arranged at substantially equal intervals.

The base end of the reflection unit 86 is fixed to the rotating shaft 20 via the table base 18, like the reflection unit 26. As shown in FIG. Reflection unit 86 also includes arm 28 , first reflection block 30 and second reflection block 34 , similar to reflection unit 26 .

That is, the reflection unit 86 also has an inclined surface 30b including the first mirror surface 30c and an inclined surface 34b including the second mirror surface 34c. can irradiate to the head portion 64a.

However, the distance A2 from the center position 10c of the holding surface 10a (that is, the center 20a of the rotating shaft 20 (see FIG. 4)) to the through hole 88 of the reflecting unit 86 in the longitudinal direction 28a is It is longer than the distance A1 to the through hole 28b of the reflection unit 26.

FIG. 7B is a top view of the holding unit 12 and the like on which a chuck table 80 having a second diameter 80b is mounted instead of the chuck table 10. FIG. In FIG. 7B, the outer peripheral edge 31e of the wafer 31 whose back surface 31b side is suction-held by the holding surface 80a is indicated by a dashed line.

As shown in FIG. 7B, the outer peripheral edge 31e of the wafer 31 is located directly above the through holes 88 of the four reflection units 86. As shown in FIG. Therefore, the light 32b emitted from the light emitting unit 32 passes through the pair of inclined surfaces (the inclined surfaces 30b and 34b) of each reflection unit 86 and is irradiated onto the outer peripheral portion 31d of the wafer 31. As shown in FIG.

The coordinates of the three points on the outer peripheral edge 31e of the wafer 31 are defined with the center position (coordinates) 80c of the holding surface 80a as the origin. The center position (not shown) of the surface 11a of the wafer 31 is calculated based on the center position 80c and coordinates of three points corresponding to the outer peripheral edge 11e.

Note that the imaging unit 36 should have at least three reflection units 26 and at least three reflection units 86 in order to calculate the respective center positions of the surfaces 11a and 31a.

In the second embodiment, when chuck tables 10 and 80 having different sizes are used, wafers having different diameters are used by using either at least three reflection units 26 or at least three reflection units 86 . The coordinates of the outer peripheral edges 11e and 31e of 11 and 31 can be specified respectively.

By the way, in the second embodiment, the case where the reflection unit 26 is used to image the wafer 11 with a diameter of 8 inches and the reflection unit 86 is used to image the wafer 31 with a diameter of 12 inches has been described. However, the diameters of the wafers 11 and 31 are not limited to this example.

In addition, the reflection unit 26 is used to image the outer peripheral portion of the wafer with the smallest diameter, the reflection unit 86 is used to image the outer peripheral portion of the intermediate diameter wafer, and the reflection units 26 and 86 are not used to image the outer peripheral portion of the wafer. It is also possible to image the outer periphery of a large-diameter wafer.

For example, the reflection unit 26 is used to image the wafer 11 with a diameter of 6 inches, the reflection unit 86 is used to image the wafer 31 with a diameter of 8 inches, and the diameter is imaged without using the reflection units 26 and 86. The imaging unit 36 may be configured to image the periphery of a 12-inch wafer.

(Third Embodiment) Next, a third embodiment will be described with reference to FIG. FIG. 8 is a partial cross-sectional side view showing a reflecting unit 90 according to the third embodiment. One reflecting unit 90 has both through holes 28b and 88. FIG.

The second reflecting block 34 is slidably connected to the arm portion 28 along the longitudinal direction 28a. The second reflection block 34 is positioned so that the second mirror surface 34c is positioned directly below the through hole 28b or the through hole 88. As shown in FIG.

The movement method of the second reflection block 34 may be a manual movement type in which an operator manually moves it, or an automatic movement type in which the control unit 70 controls a ball screw type movement mechanism to move it to a predetermined position. .

By providing at least three reflection units 90 at different positions along the circumferential direction of the table base 18 , both functions of the reflection units 26 and 86 can be implemented in one reflection unit 90 .

(Modification) Next, a modification will be described with reference to FIGS. 9 to 11. FIG. Although FIGS. 9 to 11 show modifications of the first embodiment, the modifications are similarly applicable to the second and third embodiments.

FIG. 9 is an enlarged view of a holding unit 12 according to a modification. FIG. 10 is a partial cross-sectional side view showing how the outer peripheral portion 11d of the wafer 11 is imaged. FIG. 11 is a partial cross-sectional side view showing how an outer peripheral portion 31d of a wafer 31 having a diameter larger than that of the wafer 11 is imaged.

An annular auxiliary table 14c having an outer diameter larger than that of the chuck table 10 is provided integrally with the frame 14a on the outer periphery of the frame 14a of the chuck table 10 according to the modification.

The upper surface of the auxiliary table 14c includes an annular outer upper surface _14c1 that is substantially parallel to the XY plane and substantially flat. The outer upper surface _14c1 is positioned lower than the holding surface 10a. The outer upper surface 14 c ₁ in this embodiment is lower than the holding surface 10 a by a length corresponding to the depth of the circular recess 21 of the wafer 11 .

Therefore, even when a wafer 31 having a diameter larger than that of the wafer 11 is placed on the chuck table ₁₀ as shown in FIG. The wafer 31 can be held by suction while preventing the bending of the wafer 31 .

An annular inner upper surface 14c- ₂ located inside the outer upper surface 14c- ₁ is inclined so as to become lower as it progresses from the outer side to the inner side in the radial direction of the frame 14a. A cylindrical through-hole 14d is formed in a region including a boundary 14c- ₃ between the outer upper surface 14c- ₁ and the inner upper surface 14c- ₂ .

As shown in FIG. 10, the through hole 14d is positioned above the through hole 28b of the reflecting unit 26, and the light 32b reflected by the reflecting unit 26 passes through the through hole 14d and is attracted by the holding surface 10a. The outer peripheral portion 11d of the held wafer 11 is irradiated.

On the other hand, when imaging the outer peripheral portion 31d of the wafer 31, the outer peripheral portion 31d of the wafer 31 is directly irradiated with the light 32b without using the reflection unit 26, as shown in FIG.

In this way, if the chuck table 10 having the auxiliary table 14c is used, the wafer 11 can be held by suction on the chuck table 10, and furthermore, the chuck table 80 can be replaced with a chuck table 80 having a diameter larger than that of the chuck table 10. A wafer 31 with a large diameter can be held by suction.

In addition, the structures, methods, and the like according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention. For example, the outer peripheral portion 11 d of the wafer 11 on which the circular concave portion 21 is not formed can be similarly processed using the laser processing device 2 .

By the way, the content similar to that of the above-described embodiment is cutting for removing the annular convex portion 23 and the like by subjecting the outer peripheral portions 11d and 31d of the wafers 11 and 31 to edge trimming (i.e., predetermined processing such as cutting). It can also be implemented in a device (processing device) (not shown).

The cutting device has a cutting unit (processing unit) instead of the laser processing unit 62 . The cutting unit includes a tubular spindle housing having a longitudinal portion arranged parallel to the Y-axis direction. A part of a cylindrical spindle is rotatably accommodated in the spindle housing.

A rotational drive source such as a motor is provided at the base end of the spindle. A tip of the spindle protrudes from the spindle housing. A cutting blade having an annular cutting edge is attached to the tip of the spindle.

A head portion 64a of the camera portion 64 is provided at a position adjacent to the tip portion of the spindle in the X-axis direction. This head portion 64a is fixed to the spindle housing.

The cutting device has a ball-screw type cutting feed unit that moves the spindle housing along the Z-axis direction. An indexing feed unit is connected to the incision feed unit to move the spindle housing along the Y-axis direction.

A table base 18, a rotating shaft 20, and a drive section 22 are provided below the cutting unit. A clamp unit 24 and a reflection unit 26 are provided on the table base 18 in the same manner as in the above embodiments. One of the chuck tables 10, 80 is mounted on the table base 18 in a replaceable manner.

The drive unit 22 is supported by an X-axis moving plate 40 . The X-axis movement plate 40 and the like constitute a ball screw type X-axis movement unit (processing feed unit) 48 . A light emitting unit 32 is provided on the upper surface of the X-axis movement plate 40 . At least three reflection units 26 , light emission units 32 , camera section 64 and the like constitute an imaging unit 36 .

Even in the cutting apparatus, when chuck tables 10 and 80 having different sizes are used, the outer peripheral portions 11d and 31d of the wafers 11 and 31 having different diameters can be adjusted simply by selecting whether to use at least three reflection units 26 or the like. Each coordinate can be specified.

Therefore, it is possible to provide an optical system that can be used for chuck tables 10 and 80 having different diameters. Furthermore, compared to the case where a dedicated truncated cone corresponding to the diameter of the chuck tables 10, 80 is attached to each of the chuck tables 10, 80 of different sizes, it is possible to reduce the labor required to replace the truncated cone. Note that the second and third embodiments and modifications can also be applied to the cutting device.

2: Laser processing equipment (processing equipment)
4: Base, 6: Base, 8: Wall 10: Chuck table (first holding table)
10a: holding surface, 10b: first diameter, 10c: center position 11: wafer (first wafer)
11a: front surface (one surface), 11a ₁ : center position, 11b: back surface 11c: notch, 11d: outer peripheral portion, 11e: outer peripheral edge 12: holding unit 13: planned division line, 15: device, 17: device area, 17a: Boundary 14a: Frame 14b: Porous plate 14c: Auxiliary table 14c ₁ : Outer upper surface 14c ₂ : Inner upper surface 14c ₃ : Boundary 14d: Through hole 16: Suction source 18: Table base 20: Rotation shaft 20a : center 22: drive unit 19: outer peripheral surplus region 21: circular concave portion 23: annular convex portion 24: clamp unit 25: tape 27: annular frame 29: wafer unit 26: reflection unit (first reflection unit)
28: arm, 28a: longitudinal direction, 28b: through hole 30: first reflection block, 30a: vertical plane, 30b: inclined surface, 30c: first mirror surface 31: wafer (second wafer)
31a: front surface (one surface), 31b: back surface, 31d: outer peripheral portion, 31e: outer peripheral edge 32: light emitting unit, 32a: light source, 32b: light 34: second reflection block, 34a: opening, 34b: inclined surface, 34c: Second mirror surface 36: Imaging unit 40: X-axis direction moving plate 41: Circular recess 42: X-axis guide rail 44: Screw shaft 46: Drive source 48: X-axis direction moving unit 50: Y-axis direction moving plate 52: Y-axis guide rail 54: screw shaft 56: drive source 58: Y-axis movement unit 60: arm 62: laser processing unit (processing unit) 62a: condenser 64: camera unit 64a: head unit 66: Case 68: Touch panel 70: Control unit 80: Chuck table (second holding table)
80a: holding surface, 80b: second diameter, 80c: center position 86: reflection unit (second reflection unit), 88: through hole 90: reflection units A1, A2: distance

Claims (4)

A processing device that is used to calculate the center position of one surface of a disk-shaped wafer and performs predetermined processing on the outer peripheral portion of the wafer,
a holding unit that holds the wafer;
a processing unit for processing the wafer;
an imaging unit for imaging the outer peripheral portion of the wafer held by the holding unit;
with
The holding unit is
a disc-shaped holding table for sucking and holding the wafer;
a rotating shaft coupled to the holding table for rotating the holding table;
a drive unit that rotates the rotating shaft;
has
The imaging unit is
camera section,
a light emitting unit provided below the camera unit and including a light source;
Each of them is fixed to the rotating shaft, arranged on the outer peripheral portion of the holding table so as to be separated from each other along the circumferential direction of the holding table, and has a pair of opposing inclined surfaces. at least three reflective units capable of upwardly emitting light from the light source through;
has
By adjusting the position of each reflection unit in the imaging unit, the wafer having a diameter larger than that of the holding table and protruding outside in the radial direction of the holding table when suction-held by the holding table is removed. A processing apparatus, wherein light from the light source is sequentially applied to an outer peripheral portion of the wafer from each reflection unit, and at least three locations on the outer peripheral portion of the wafer are imaged by the imaging units. The at least three reflective units are
When a first holding table having a first diameter is used as the holding table in the holding unit, when sucked and held by the first holding table, it is radially outward of the first holding table. at least three first reflection units each capable of irradiating the light from the light source to the outer peripheral portion of the first wafer that protrudes and has a diameter larger than the first diameter;
When a second holding table having a second diameter larger than the first diameter is used as the holding table in the holding unit instead of the first holding table, suction is performed by the second holding table. Light from the light source is applied to the outer peripheral portion of the second wafer, which protrudes radially outward of the second holding table when held and has a diameter larger than the second diameter. at least three second reflection units each capable of irradiating the
2. The processing apparatus according to claim 1, comprising: The holding unit further has an annular auxiliary table provided on the outer periphery of the holding table,
3. The processing apparatus according to claim 1, wherein the auxiliary table includes a through hole for irradiating the outer peripheral portion of the wafer with the light reflected by each reflecting unit. The pair of inclined surfaces of each reflecting unit is inclined by 45 degrees with respect to a plane orthogonal to the longitudinal direction of the reflecting unit on which the pair of inclined surfaces are provided so as to irradiate the light from the light source upward. 4. A processing apparatus according to any one of claims 1 to 3, comprising one mirror surface and a second mirror surface.

Images