JP2006032661A - Cutting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To securely position the center of a semiconductor wafer 4 to the center O of rotation of a chuck table 6. <P>SOLUTION: The cutting apparatus includes: the rotatable chuck table 6 having a holding upper surface 42a placing and holding the semiconductor wafer 4, and having a frame 44 surrounding the holding upper surface 42a; and cutting means for cutting the semiconductor wafer 4 held on the holding upper surface 42a. There is disposed, on the frame 44, a center positioning means for acting on an outer peripheral surface of the semiconductor wafer 4 placed on the holding upper surface 42a, and for positioning the semiconductor wafer 4 concentrically to the center O of rotation of the chuck table 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a cutting device, and more particularly to a semiconductor wafer cutting device.

A semiconductor wafer having a plurality of circuits such as IC and LSI formed on the front surface is divided into individual semiconductor chips by grinding the entire back surface to reduce its thickness. The divided semiconductor chips are used for electronic devices such as mobile phones and personal computers. In recent years, in order to meet the demand for further weight reduction and miniaturization of these electronic devices, the thickness of semiconductor wafers has become extremely thin such as 100 μm or less and 50 μm or less.

By the way, the outer peripheral surface of the semiconductor wafer is chamfered in an arc shape in order to prevent problems such as chipping that occur when the semiconductor wafer is moved between the processes until it is divided into semiconductor chips. As described above, when the back surface of the semiconductor wafer having an arc-shaped chamfered portion on the outer periphery is thinned by grinding (polishing) with a grinding wheel, a sharp knife edge is formed on the arc-shaped chamfered portion. For this reason, the semiconductor wafer may be damaged during grinding of the semiconductor wafer or during transportation of the semiconductor wafer.

Therefore, in order to solve such a problem, the semiconductor wafer is held on the chuck table of the dicing apparatus, the cutting blade is applied to the upper surface of the outer peripheral edge of the semiconductor wafer, the chuck table is rotated, and the arc-shaped chamfered portion is formed. A technique of cutting at right angles to the upper surface has also been proposed (see Patent Document 1).

However, it is difficult to position the center of the semiconductor wafer at the center of rotation of the chuck table, and when the outer peripheral edge of the semiconductor wafer is cut, a part of the arc-shaped chamfer is not sufficiently cut or the cutting blade is in the radial direction. There is a possibility that a problem such as damage to the circuit forming part may occur due to excessive entry inside.
JP 2003-273053 A

The object of the present invention is to make it possible to reliably position the center of the semiconductor wafer at the center of rotation of the chuck table. It is to provide a novel cutting device that can be prevented.

According to the present invention,
A holding upper surface capable of mounting and holding a semiconductor wafer, a chuck table having a frame surrounding the holding upper surface, and a rotatable chuck table, and a cutting means for cutting the semiconductor wafer held on the holding upper surface of the chuck table In the provided cutting device,
The frame of the chuck table is provided with center positioning means that acts on the outer peripheral surface of the semiconductor wafer placed on the holding upper surface to position the semiconductor wafer concentrically with the center of rotation of the chuck table. Has been established,
A cutting device is provided.
The center positioning means includes: a first pressing unit; a pressing position that presses the first pressing unit against the outer peripheral surface of the semiconductor wafer; and a non-pressing position that is separated from the outer peripheral surface of the semiconductor wafer. A first moving means, a second pressing unit, and a second pressing unit that move horizontally between a direction approaching the rotation center and a direction moving away from the rotation center. A second position of moving horizontally between a pressing position pressed against the outer peripheral surface of the semiconductor wafer and a non-pressing position away from the outer peripheral surface of the semiconductor wafer in a direction approaching the rotation center and a direction moving away from the rotation center, respectively. The second pressing unit is disposed on the opposite side in the radial direction with respect to the first pressing unit with respect to the rotation center, and the first pressing unit and the second pressing unit. Caul units, respectively, is moved to the pushing against position from the pressing non positions by the first and second moving means, the semiconductor wafer is positioned coaxially with respect to the rotation center, it is preferable.
The first pressing unit includes two first pressing members arranged at intervals in the circumferential direction of the chuck table, and the second pressing unit includes one second pressing unit. A pressing member having an arc shape when viewed in the axial direction of the chuck table is formed at the tip of each of the first pressing members and the tip of the second pressing member, When the first and second pressing units are respectively moved to the pressing position, each of the first pressing members and the pressing surface of the second pressing member are respectively It is preferable that the semiconductor wafer is positioned concentrically with respect to the center of rotation by being pressed against the outer peripheral surface of the semiconductor wafer placed on the holding upper surface of the chuck table.
The second pressing unit is provided with spring means for reducing the pressing force when the pressing surface of the second pressing member is pressed against the outer peripheral surface of the semiconductor wafer. Is preferable.
Each of the first pressing member and the second pressing member is formed with a flange extending horizontally from the upper end of the pressing surface, and each of the first pressing member and the second pressing member With the second pressing members pressed against the outer peripheral surface of the semiconductor wafer placed on the holding upper surface of the chuck table, each of the flanges is located above the outer peripheral edge of the semiconductor wafer. Are preferably positioned so as to cover with a gap.
The first moving means includes a first air cylinder mechanism supported by the frame body of the chuck table, and the first pressing unit is supported by a piston rod of the first air cylinder mechanism. The second moving means includes a second air cylinder mechanism supported by the frame body, and the second pressing unit is supported by a piston rod of the second air cylinder mechanism. It is preferable.
The first pressing unit includes a first support frame, and each of the first pressing members is supported by the first support frame, and the first support frame is the first air cylinder mechanism. The second pressing unit includes a second support frame, and each of the second pressing members is supported by the second support frame, and the second support frame is supported by the piston rod. Is preferably supported by the piston rod of the second air cylinder mechanism.
On the outer peripheral surface of the frame body of the chuck table, a first movement blocking surface for blocking movement of each of the first pressing members in a direction approaching the rotation center, and the second A second movement preventing surface for preventing the pressing member from moving in a direction approaching the rotation center is formed, and each of the first pressing members corresponds to the first movement preventing surface. It is preferable that a first movement blocked surface is formed, and a second movement blocked surface is formed on the second support frame corresponding to the second movement blocking surface.
Air ejecting means is provided that can eject air onto the holding upper surface of the chuck table and form an air layer between the semiconductor wafer placed on the holding upper surface and the holding upper surface. Is preferable.

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

First, referring to FIG. 1, the cutting device in the illustrated embodiment includes a device housing 2 having a substantially rectangular parallelepiped shape. In the apparatus housing 2, a chuck table 6 that holds a semiconductor wafer 4 (see FIG. 2) that is a workpiece, a spindle unit 8 that is a cutting means, and a surface of the semiconductor wafer 4 held on the chuck table 6. An image pickup mechanism 10 for picking up an image and detecting a cutting region or confirming a state of a cutting groove, a display means 12 for displaying an image picked up by the image pickup mechanism 10, a workpiece placed in a cassette placement region A cassette placing mechanism 16 for placing a cassette 14 containing a semiconductor wafer 4, and a workpiece unloading for unloading a semiconductor wafer 4 that is a workpiece housed in the cassette 14 placed on the cassette placing mechanism 16. It is carried to the alignment mechanism 20 and the alignment mechanism 20 for aligning the semiconductor wafer 4 unloaded by the mechanism 18 and the workpiece unloading mechanism 18. The first transport mechanism 22 for transporting the positioned semiconductor wafer 4 to the chuck table 6, the cleaning means 24 for cleaning the semiconductor wafer 4 cut on the chuck table 6, and cutting on the chuck table 6. A second transport mechanism 26 for transporting the processed semiconductor wafer 4 to the cleaning means 24 is provided.

The chuck table 6 described in detail later is disposed so as to be movable in a direction indicated by an arrow X that is a cutting feed direction. The spindle unit 8 is mounted on a moving base (not shown) and is adjusted to move in a direction indicated by an arrow Y that is an indexing direction and a direction indicated by an arrow Z that is a cutting direction. The rotary spindle 32 is supported and rotated by a rotary drive mechanism (not shown), and a cutting blade 34 attached to the rotary spindle 32 is provided. As for the spindle unit 8 and the other mechanisms and means described above, known mechanisms and means disclosed in Japanese Patent Application Laid-Open No. 2003-163253 may be used, and do not constitute the features of the present invention. Further explanation is omitted.

Next, the chuck table 6 having the features of the present invention will be described. 2 to 4, the chuck table 6 includes a suction chuck support base 40 and a suction chuck 42 mounted on the suction chuck support base 40. The suction chuck support base 40 includes a frame body 44 having a substantially circular outer peripheral surface, and a support shaft 46 extending vertically downward from the lower surface of the central portion of the frame body 44. The lower end portion of the support shaft 46 is rotatably supported by a stationary base 48 disposed in the apparatus housing 2 (FIG. 1) via a bearing (not shown). The support shaft 46 is drivingly connected to an electric motor M that is a driving source. A recess 50 having a constant depth and a circular outer peripheral surface is formed on the upper surface of the central portion of the frame body 44. The suction chuck 42 is press-fitted and held in the recess 50. The suction chuck 42 is formed of a member having air permeability, for example, porous ceramic, and includes a thickness substantially the same as the depth of the recess 50 and an outer peripheral surface having a diameter substantially the same as the diameter of the recess 50. . In a state where the suction chuck 42 is held in the recess 50 of the frame body 44, the upper surface of the frame body 44 and the upper surface 42a of the suction chuck 42 are positioned on a substantially common horizontal plane. The upper surface 42 a of the suction chuck 42 functions as a holding upper surface 42 a for placing and holding the semiconductor wafer 4, and the frame body 44 constitutes a frame body 44 that surrounds the suction chuck 42.

A rotary joint 52 is fixed to the center of the upper end of the stationary base 48. The support shaft 46 penetrates the central portion of the rotary joint 52 so as to be relatively rotatable. An annular space 54 is formed between the inner peripheral surface of the rotary joint 52 and the outer peripheral surface of the support shaft 46. A ventilation path 56 is formed in the suction chuck support base 40. The upper end of the air passage 56 opens to the central lower surface of the recess 50 of the frame body 44, and the lower end of the annular space 54 formed between the inner peripheral surface of the rotary joint 52 via the outer peripheral surface of the support shaft 46. Is open. The annular space 54 is connected to an electromagnetic switching valve V that is a passage switching valve via a ventilation path 58. The electromagnetic switching valve V is connected to an air pump AP that is a pressure air supply source via a ventilation path 60 and is connected to a vacuum pump VP that is a negative pressure generation source via a ventilation path 62. The electromagnetic switching valve V, which may use a configuration known per se, includes an atmospheric release position for opening the ventilation path 58 to the atmosphere, and a pressure air supply position for communicating the ventilation path 58 with the air pump AP via the ventilation path 60. The negative pressure supply position for communicating the ventilation path 58 with the vacuum pump VP via the ventilation path 62 is selectively controlled by a controller (not shown).

Therefore, when the disk-shaped semiconductor wafer 4 is placed on the holding upper surface of the suction chuck 42, and the air pump AP is driven by switching the electromagnetic switching valve V to the pressure air supply position by a controller (not shown), Since air is ejected to 42a, an air layer is formed between the semiconductor wafer 4 placed on the holding upper surface 42a and the holding upper surface 42a, and the semiconductor wafer 4 is substantially floated with respect to the holding upper surface 42a. . Further, when the electromagnetic switching valve V is switched to the negative pressure supply position and the vacuum pump VP is driven, a negative pressure is generated on the holding upper surface 42a of the suction chuck 42, so that the semiconductor wafer 4 is sucked and held by the holding upper surface 42a. The Furthermore, when the electromagnetic switching valve V is switched to the atmospheric release position with the driving of the air pump AP and the vacuum pump VP stopped, the holding upper surface 42a of the suction chuck 42 is held at atmospheric pressure, so that the semiconductor wafer 4 is Then, it is in a state of being naturally placed on the holding upper surface.

The air passage 56, the annular space 54, the air passage 58, the electromagnetic switching valve V, the air pump AP, and the like eject air to the holding upper surface 42a of the chuck table 6, that is, the holding upper surface 42a of the chucking chuck 42, to the holding upper surface 42a. An air ejecting means capable of forming an air layer between the mounted semiconductor wafer 4 and the holding upper surface 42a is configured.

The frame 44 of the chuck table 6 acts on the outer peripheral surface of the semiconductor wafer 4 placed on the holding upper surface 42 a of the suction chuck 42, so that the semiconductor wafer 4 is concentric with the rotation center O of the chuck table 6. Center positioning means for positioning are arranged. The center positioning means includes a first pressing unit 100, a first air cylinder mechanism 102 as a first moving means, a second pressing unit 104, and a second air as a second moving means. And a cylinder mechanism 106.

The first air cylinder mechanism 102 presses the first pressing unit 100 against the outer peripheral surface of the semiconductor wafer 4 (the semiconductor wafer 4 placed on the holding upper surface 42a of the suction chuck 42) (see FIG. 3) and a non-pressing position (position shown in FIG. 5) away from the outer peripheral surface of the semiconductor wafer 4 horizontally moving in a direction approaching the rotation center O and a direction away from the rotation center O, respectively. Let The second air cylinder mechanism 106 presses the second pressing unit 104 against the outer peripheral surface of the semiconductor wafer 4 (the semiconductor wafer 4 placed on the holding upper surface 42a of the suction chuck 42) (see FIG. 3) and a non-pressing position (a position indicated by a solid line in FIG. 3 and a position shown in FIG. 5) away from the outer peripheral surface of the semiconductor wafer 4, respectively, approach the rotation center O. Move horizontally in the direction and away from the center of rotation O. The second pressing unit 104 and the second air cylinder mechanism 106 are arranged on the opposite side in the radial direction with respect to the first pressing unit 100 and the first air cylinder mechanism 102 with the rotation center O in between. . When the first and second pressing units 100 and 104 are moved from the non-pressing position to the pressing position by the first and second air cylinder mechanisms 102 and 106, respectively, the semiconductor wafer 4 is rotated at the center of rotation O. Is positioned concentrically.

More specifically, the first pressing unit 100 is spaced apart from the first support frame 108 that extends substantially radially outward of the frame 44 of the chuck table 6 in the circumferential direction. And two first pressing members 110 and 112 supported at both ends of the first support frame 108. Both end portions of the first support frame 108 have inner surfaces extending in a tangential direction with respect to the outer peripheral surface of the frame body 44 of the suction chuck support base 40, and the first pressing members 110 and 112 are , Respectively, are supported on the inner surface. The first pressing members 110 and 112 having substantially the same configuration as each other and extending horizontally are pressed at the tips of the respective pressing members 110 and 112 each having an arc shape when viewed in the axial direction of the chuck table 6. Surfaces 114 and 116 are formed. Drooping pieces 118 and 120 extending vertically downward are formed at the rear end portions of the first pressing members 110 and 112, respectively. The drooping pieces 118 and 120 have inner side surfaces extending in a tangential direction with respect to the outer peripheral surface of the frame body 44 of the suction chuck support base 40. In each of the first pressing members 110 and 112, flanges 122 and 124 are formed so as to extend horizontally from the upper ends of the pressing surfaces 114 and 116, respectively.

The first air cylinder mechanism 102 includes a cylinder 126, a piston (not shown) disposed in the cylinder 126, and a piston rod 128 connected to the piston. The cylinder 126 is a pair of supports fixed to the frame body 44 so as to extend from the outer peripheral surface of the frame body 44 of the suction chuck support base 40 in parallel to the outer side in the radial direction and spaced horizontally from each other in the circumferential direction. Supported between frames 130 and 132. The first support frame 108 of the first pressing unit 100 is supported by the tip of the piston rod 128. The axis L1 of the piston rod 128 is positioned on a horizontal axis that passes through the rotation center O of the chuck table 6.

A first movement that prevents the first pressing members 110 and 112 from moving in the direction approaching the rotation center O of the chuck table 6 on the outer peripheral surface of the frame 44 of the suction chuck support base 40, respectively. Blocking surfaces 44a and 44b are formed. The first movement preventing surfaces 44 a and 44 b are arranged at positions spaced apart in the circumferential direction, and are formed so as to extend in the tangential direction with respect to the outer circumferential surface of the frame body 44. Each of the first pressing members 110 and 112 is formed with first movement blocked surfaces 110a and 112b corresponding to the first movement blocking surfaces 44a and 44b, respectively. The first movement blocked surface 110 a is defined by the inner side surface of the hanging piece 118, and the first movement blocked surface 112 b is defined by the inner side surface of the hanging piece 120. When the first pressing unit 100 is positioned at the non-pressing position, the first movement blocked surfaces 110a and 112b are respectively radially outward with respect to the first movement blocking surfaces 44a and 44b. Positioned at a distant location.

The second pressing unit 104 includes a second support frame 134 disposed on the outer side in the radial direction of the frame body 44 of the chuck table 6, and one second pressing frame supported by the second support frame 134. A member 136 is provided. The second support frame 134 has an inner surface extending in a tangential direction with respect to the outer peripheral surface of the frame body 44 of the suction chuck support base 40, and the second pressing member 136 is disposed on the inner surface. It is supported. A pressing surface 138 having an arc shape when viewed in the axial direction of the chuck table 6 is formed at the tip of the second pressing member 136 extending horizontally. A hanging piece 140 that extends vertically downward is formed at the rear end of the second pressing member 136. The hanging piece 140 has an inner surface extending in a tangential direction with respect to the outer peripheral surface of the frame body 44 of the suction chuck support base 40. A flange 142 is formed on the second pressing member 136 so as to extend horizontally from the upper end of the pressing surface 138.

The second pressing unit 104 is pressed when the pressing surface 138 of the second pressing member 136 is pressed against the outer peripheral surface of the semiconductor wafer 4 mounted on the holding upper surface 42a of the suction chuck 42. Spring means for relieving the force, in the embodiment two compression coil springs 144 and 146 are provided. That is, two rods 148 and 150 extend horizontally and parallel to each other in the direction approaching the rotation center O of the chuck table 6 from the upper end portion of the inner surface of the second support frame 134. The second pressing member 136 is slidably supported by the rods 148 and 150. The compression coil springs 144 and 146 are disposed so as to cover the periphery of the rods 148 and 150, respectively, and are disposed between the inner surface of the second support frame 134 and the second pressing member 136. A stopper (not shown) is disposed at the tip (not shown) of the rods 148 and 150, and restricts the movement of the second pressing member 136 in the direction approaching the rotation center O of the chuck table 6.

The second air cylinder mechanism 106 includes a cylinder 152, a piston (not shown) disposed in the cylinder 152, and a piston rod 154 connected to the piston. The cylinder 152 is a pair of supports fixed to the frame body 44 so as to extend from the outer peripheral surface of the frame body 44 of the suction chuck support base 40 to the outer side in the radial direction and in parallel to the outer side in the radial direction. Supported between frames 156 and 158. The second support frame 134 of the second pressing unit 104 is supported by the tip of the piston rod 154. The axis L2 of the piston rod 154 is positioned on a horizontal axis passing through the rotation center O of the chuck table 6. In the embodiment, the axis L2 of the piston rod 154 is positioned on the common horizontal axis with the axis L1 of the piston rod 128.

On the outer peripheral surface of the frame body 44 of the suction chuck support base 40, a second movement preventing surface 44 c is formed that prevents the second support frame 134 from moving in the direction approaching the rotation center O of the chuck table 6. Yes. The second movement prevention surface 44 c is formed so as to extend in the tangential direction with respect to the outer peripheral surface of the frame body 44. A second movement blocked surface 160 is formed on the support frame 134 corresponding to the second movement blocking surface 44c. As described above, the second support frame 134 has an inner surface extending in the tangential direction with respect to the outer peripheral surface of the frame body 44 of the suction chuck support base 40, and the second support frame 134. Is provided with a protrusion 162 extending horizontally from the lower end portion of the inner surface toward the outer peripheral surface of the frame body 44, more specifically, toward the second movement preventing surface 44c. The second movement blocked surface 160 is defined by the tip surface of the protrusion 162. When the second pressing unit 104 is positioned at the non-pressing position, the second movement blocked surface 160 is positioned at a position radially away from the second movement blocking surface 44c. . In addition, in order to avoid complication of a figure, illustration of this protrusion part 162 is abbreviate | omitted in FIG.3 and FIG.5.

The operation of the cutting apparatus configured as described above will be described. The operations other than the chuck table 6 having the features of the present invention will be described schematically. 1 to 4, a cassette 14 containing a plurality of semiconductor wafers 4 is placed on the cassette table of the cassette placing mechanism 16 and lowered and raised by the cassette placing mechanism 16. The cassette lid of the cassette 14 is removed. In response to a cutting operation start command, the workpiece carry-out mechanism 18 advances and retreats, and the semiconductor wafer 4 accommodated in the cassette 14 is conveyed onto the center table of the alignment mechanism 20. The semiconductor wafer 4 aligned by the alignment mechanism 20 is placed on the holding upper surface 42 a of the suction chuck 42 of the chuck table 6 by the first transport mechanism 22. At this time, the first and second pressing units 100 and 104 are positioned at the pressed positions (see FIG. 5), respectively.

After the semiconductor wafer 4 is placed on the holding upper surface 42 a of the suction chuck 42, the first pressing unit 100 positioned at the non-pressing position (FIG. 5) is moved by the first air cylinder mechanism 102 to the chuck table 6. Is moved in a direction approaching the rotation center O. When the first movement blocked surfaces 110a and 112b of the first pressing members 110 and 112 are brought into contact with the first movement blocking surfaces 44a and 44b of the frame 44, respectively, the first pressing members The first pressing unit 100 including 110 and 112 is prevented from moving, and the first pressing unit 100 including the first pressing members 110 and 112 is positioned at the pressing position (FIG. 3). In this state, when viewed in the axial direction of the chuck table 6, a horizontal straight line connecting the arc center (curvature center) of the pressing surface 114 forming the arc shape of the first pressing member 110 and the circumferential center of the arc. L3 is positioned so as to pass through the rotation center O of the chuck table 6, and the arc center (curvature center) of the pressing surface 116 forming the arc shape of the first pressing member 112 and the circumferential center of the arc are defined. The connecting horizontal straight line L4 is positioned so as to pass through the rotation center O of the chuck table 6. As shown in FIG. 3, the angle formed by the straight line L3 and the straight line L1 is equal to the angle formed by the straight line L4 and the straight line L1. The leading ends (the leading ends closest to the rotation center O) of the pressing surfaces 114 and 116 of the first pressing members 110 and 112 are respectively when the semiconductor wafer 4 is positioned at the rotation center O of the chuck table 6. It is positioned at a position where the outer peripheral surface exists.

The non-pressing position (shown by the solid line in FIG. 3) is slightly delayed from the timing at which the first pressing unit 100 is moved in the direction approaching the rotation center O of the chuck table 6 by the first air cylinder mechanism 102. The second pressing unit 104 positioned at the position shown in FIG. 5 and the position shown in FIG. 5 is moved by the second air cylinder mechanism 106 in a direction approaching the rotation center O of the chuck table 6. When the second movement blocked surface 160 defined by the tip surface of the projecting portion 162 of the second support frame 134 is brought into contact with the second movement blocking surface 44c of the frame body 44, the second pushing The movement of the second pressing unit 104 including the pressing member 136 is prevented, and the second pressing unit 104 including the second pressing member 136 has a pressing position (a position indicated by a two-dot chain line in FIG. 3). Positioned on. In this state, when viewed in the axial direction of the chuck table 6, a horizontal straight line connecting the arc center (curvature center) of the pressing surface 138 forming the arc shape of the second pressing member 136 and the circumferential center of the arc. Is positioned so as to coincide with the straight line L2 (this state is when the second pressing unit 104 is positioned at the non-pressing position (the position shown by the solid line in FIG. 3 and the position shown in FIG. 5). Is the same). The leading edge of the pressing surface 138 of the second pressing member 136 (the cutting edge closest to the rotation center O) is the outer peripheral surface when the semiconductor wafer 4 is positioned at the rotation center O of the chuck table 6. It is positioned slightly inward in the radial direction from the position where This difference is substantially equal to the amount of deflection of the compression coil springs 144 and 146. The inner surface of the hanging piece 140 of the second pressing member 136 is positioned with a gap with respect to the second movement prevention surface 44 c of the frame body 44.

Thus, when the first and second pressing units 100 and 104 are moved to the pressing position, respectively, the pressing surfaces 114 and 116 of the first pressing members 110 and 112, and The pressing surface 138 of the second pressing member 136 is pressed against the outer peripheral surface of the semiconductor wafer 4 placed on the holding upper surface 42 a of the suction chuck 42, so that the semiconductor wafer 4 is concentric with the rotation center O. Positioned on top. Since the second pressing member 136 is slightly moved radially outward by the deflection of the compression coil springs 144 and 146, the pressing force against the outer peripheral surface of the semiconductor wafer 4 is relieved. As a result, the impact on the semiconductor wafer 4 is mitigated, and damage to the outer peripheral surface and the like is prevented without applying an excessive load to the semiconductor wafer 4. Since the pressing surfaces 114 and 116 of the first pressing members 110 and 112 and the pressing surface 138 of the second pressing member 136 have an arc shape, they are viewed in the axial direction of the chuck table 6. The semiconductor wafer 4 is brought into point contact with the outer peripheral surface, thereby facilitating the centering operation without applying an excessive load to the semiconductor wafer 4.

Corresponding to the movement of the first and second pressing units 100 and 104 to the pressing position, the electromagnetic switching valve V is switched from the atmospheric release position to the pressure air supply position to drive the air pump AP. Then, air is ejected onto the holding upper surface 42a of the suction chuck 42, so that an air layer is formed between the semiconductor wafer 4 placed on the holding upper surface 42a and the holding upper surface 42a. 42a is substantially levitated with respect to 42a. As a result, the centering operation is further facilitated without applying an excessive load to the semiconductor wafer 4.

As described above, each of the first pressing members 110 and 112 and the second pressing member 136 are formed with flanges 122, 124, and 142, respectively, so that the first pressing members 110 and 112 are formed. And the second pressing member 136 are pressed against the outer peripheral surface of the semiconductor wafer 4 placed on the holding upper surface 42a, respectively, and the flanges 122, 124, and 142 are respectively connected to the semiconductor wafer 4. It is positioned so as to cover the upper edge of the outer periphery with a gap. With this configuration, as described above, even if the semiconductor wafer 4 is substantially levitated with respect to the holding upper surface 42a, it is reliably prevented from falling off the holding upper surface 42a.

As described above, after the semiconductor wafer 4 is centered, when the electromagnetic switching valve V is switched to the negative pressure supply position and the vacuum pump VP is driven, negative pressure is generated on the holding upper surface 42a of the suction chuck 42. Therefore, the semiconductor wafer 4 is sucked and held on the holding upper surface 42 a in a state of being positioned concentrically with the rotation center O of the chuck table 6. After the semiconductor wafer 4 is sucked and held by the holding upper surface 42a, the first and second pressing units 100 and 104 are moved from the pressing position to the non-pressing position, respectively (see FIG. 5).

Thereafter, the chuck table 6 holding the semiconductor wafer 4 by suction is moved in one direction (substantially to the left in FIG. 1) indicated by an arrow X (a direction orthogonal to the rotary spindle 32 of the cutting blade 34). A part of the upper surface of the peripheral edge is positioned directly below the cutting blade 34 (see FIG. 5). Subsequently, the spindle unit 8 is moved to one side (downward) in the direction indicated by the arrow Z that is the cutting direction, and a part of the outer peripheral surface of the cutting blade 34 is partially applied to a part of the upper surface of the peripheral edge of the semiconductor wafer 4 from above. Assigned. The cutting blade 34 is moved in the cutting direction (downward) indicated by the arrow Z while being rotated, and cutting is started. The chuck table 6 is rotated at a low speed clockwise in FIG. When the chuck table 6 is rotated 360 °, a step 4A composed of a vertical surface and a horizontal surface is formed on the entire periphery of the upper surface at the peripheral edge of the semiconductor wafer 4 (see FIG. 6). The blade thickness of the cutting blade 34 is, for example, 1.0 mm to 2.0 mm.

By using a cutting blade 34 having a small diameter, a substantially channel-shaped groove 4B as shown in FIG. 7 may be formed along the periphery of the semiconductor wafer 4 on the entire periphery of the upper surface of the periphery. Easily possible. The groove 4 </ b> B includes a pair of vertical surfaces that face each other in parallel in the radial direction and a horizontal bottom surface. 6 and 7, reference numeral 4 </ b> C indicates a plurality of circuits formed on the surface of the semiconductor wafer 4.

As described above, when the step 4A or the groove 4B is formed on the entire periphery of the upper surface of the peripheral edge of the semiconductor wafer 4, the rotation of the cutting blade 34 and the chuck table 6 is stopped. The spindle unit 8 is moved to the other side (upward) in the direction indicated by the arrow Z, and is separated above the semiconductor wafer 4. After the semiconductor wafer 4 is thus cut, the chuck table 6 holding the semiconductor wafer 4 is first returned to the position where the semiconductor wafer 4 is sucked and held. Here, the electromagnetic switching valve V is set to the atmospheric release position. By switching, the suction holding of the semiconductor wafer 4 is released.

The cut semiconductor wafer 4 that has been released from suction on the chuck table 6 is transported to the cleaning means 24 by the operation of the second transport mechanism 26. The semiconductor wafer 4 transported to the cleaning means 24 is cleaned and removed by the cleaning means 24 during the cutting. The semiconductor wafer 4 cleaned by the cleaning means 24 is transferred onto the center table of the alignment mechanism 20 by the first transfer mechanism 22. The semiconductor wafer 4 conveyed on the center table of the alignment mechanism 20 is accommodated in a predetermined position of the cassette 14 positioned at the loading / unloading position by the workpiece unloading means 18. When the above cutting operation is repeatedly performed and the cutting process is completed for all the semiconductor wafers 4 accommodated in the cassette 14, a process of attaching a cassette lid to the cassette 14 is performed, and a series of operations is completed. The cassette 14 is transported to the next process by the operator.

6 and 7, the semiconductor wafer 4 in which the step 4A or the groove 4B is formed in the peripheral portion is covered with a protective film (not shown) on the surface on which the circuit 4C is formed. In this state, the entire back surface is ground by a grinding device with the front side down. Since this grinding is performed up to the vertical surface of the step 4A or the groove 4B, the outer peripheral surface of the semiconductor wafer 4 after grinding becomes a vertical surface, and no knife edge is formed. Although not shown, instead of forming the step 4A or the groove 4B on the entire periphery of the upper surface of the peripheral edge of the semiconductor wafer 4, there is another embodiment in which cutting is completely performed from the upper surface to the back surface. The outer peripheral surface of the semiconductor wafer 4 completely cut in this way is a vertical surface. Also in this embodiment, since the outer peripheral surface of the ground semiconductor wafer 4 is a vertical surface, no knife edge is formed.

In the cutting apparatus, the frame 44 of the chuck table 6 acts on the outer peripheral surface of the semiconductor wafer 4 placed on the holding upper surface 42 a, and the semiconductor wafer 4 is concentric with the rotation center O of the chuck table 6. Since the center positioning means is arranged on the upper side, the center of the semiconductor wafer 4 can be surely positioned at the rotation center O of the chuck table 6, and as a result, the outer peripheral area chamfered in an arc shape can be reliably ensured. It can be excised and damage to the circuit forming portion can be prevented.

Note that the above-described cutting apparatus according to the present invention is also applicable to the case of grinding the entire back surface (the entire top surface in FIG. 8) of one of the substrates 401 and 402 having a two-layer structure, such as the SOI substrate shown in FIG. , And the peripheral edge of one substrate 401 can be completely excised beforehand. In this case, even if the entire back surface of the substrate 401 is ground to a predetermined depth, the knife edge is not formed because the outer peripheral surface of the ground substrate 401 is a vertical surface.

It is a perspective view which shows embodiment of the cutting device by this invention. It is a perspective view which isolate | separates and shows the chuck table with which the center positioning means is arrange | positioned with the cutting apparatus shown in FIG. 1, and the semiconductor wafer mounted and hold | maintained on the holding | maintenance upper surface of a chuck table. FIG. 3 is a plan view showing a state in which a semiconductor wafer is placed on a holding upper surface of the chuck table shown in FIG. 2 and a first pressing unit is moved to a pressing position. It is principal part sectional drawing of FIG. In FIG. 3, the semiconductor wafer is held on the holding upper surface of the chuck table, the first and second pressing units are moved to the non-pressing position, and the cutting blade is applied to the upper surface of the outer peripheral edge portion of the semiconductor wafer. It is a top view which shows the state. FIG. 6 is a partial cross-sectional view showing a state in which the upper surface of the outer peripheral edge of the semiconductor wafer is cut to a predetermined depth by the cutting blade shown in FIG. 5. It is a fragmentary sectional view which shows the state by which the annular groove of predetermined depth was formed in the upper surface of the outer periphery part of a semiconductor wafer with the other cutting blade which is not shown in figure. FIG. 6 is a partial cross-sectional view showing a state in which the outer peripheral edge of one of the two substrates having a two-layer structure formed by the cutting blade shown in FIG. 5 is completely cut away.

Explanation of symbols

2: Device housing 4: Semiconductor wafer 6: Chuck table 32: Cutting blade 42: Suction chuck 42a: Holding upper surface 100: First pressing unit 102: First air cylinder mechanism 104: Second pressing unit 106: Second air cylinder mechanism 110, 112: first pressing member 136: second pressing member 114, 116, 138: pressing surface O: rotation center of chuck table

Claims (9)

A holding upper surface capable of mounting and holding a semiconductor wafer, a chuck table having a frame surrounding the holding upper surface, and a rotatable chuck table, and a cutting means for cutting the semiconductor wafer held on the holding upper surface of the chuck table In the provided cutting device,
The frame of the chuck table is provided with center positioning means that acts on the outer peripheral surface of the semiconductor wafer placed on the holding upper surface to position the semiconductor wafer concentrically with the center of rotation of the chuck table. Has been established,
The cutting device characterized by the above. The center positioning means includes: a first pressing unit; a pressing position that presses the first pressing unit against the outer peripheral surface of the semiconductor wafer; and a non-pressing position that is separated from the outer peripheral surface of the semiconductor wafer. A first moving means, a second pressing unit, and a second pressing unit that move horizontally between a direction approaching the rotation center and a direction moving away from the rotation center. A second position of moving horizontally between a pressing position pressed against the outer peripheral surface of the semiconductor wafer and a non-pressing position away from the outer peripheral surface of the semiconductor wafer in a direction approaching the rotation center and a direction moving away from the rotation center, respectively. The second pressing unit is disposed on the opposite side in the radial direction with respect to the first pressing unit with respect to the first pressing unit, and the first pressing unit and the second pressing unit. The semiconductor wafer is positioned concentrically with respect to the center of rotation when the abutting unit is moved from the non-pressing position to the pressing position by the first and second moving means, respectively. Cutting equipment. The first pressing unit includes two first pressing members arranged at intervals in the circumferential direction of the chuck table, and the second pressing unit includes one second pressing unit. A pressing member having an arc shape when viewed in the axial direction of the chuck table is formed at the tip of each of the first pressing members and the tip of the second pressing member, When the first and second pressing units are respectively moved to the pressing position, each of the first pressing members and the pressing surface of the second pressing member are respectively The cutting apparatus according to claim 2, wherein the semiconductor wafer is positioned concentrically with respect to the rotation center by being pressed against an outer peripheral surface of the semiconductor wafer placed on the holding upper surface of the chuck table. The second pressing unit is provided with spring means for reducing the pressing force when the pressing surface of the second pressing member is pressed against the outer peripheral surface of the semiconductor wafer. The cutting device according to claim 3. Each of the first pressing member and the second pressing member is formed with a flange extending horizontally from the upper end of the pressing surface, and each of the first pressing member and the second pressing member With the second pressing members pressed against the outer peripheral surface of the semiconductor wafer placed on the holding upper surface of the chuck table, each of the flanges is located above the outer peripheral edge of the semiconductor wafer. The cutting device according to claim 3, wherein the cutting device is positioned so as to cover with a gap. The first moving means includes a first air cylinder mechanism supported by the frame body of the chuck table, and the first pressing unit is supported by a piston rod of the first air cylinder mechanism. The second moving means includes a second air cylinder mechanism supported by the frame body, and the second pressing unit is supported by a piston rod of the second air cylinder mechanism. The cutting device according to any one of claims 3 to 5. The first pressing unit includes a first support frame, and each of the first pressing members is supported by the first support frame, and the first support frame is the first air cylinder mechanism. The second pressing unit includes a second support frame, and each of the second pressing members is supported by the second support frame, and the second support frame is supported by the piston rod. Is a cutting device according to claim 6, which is supported by the piston rod of the second air cylinder mechanism. On the outer peripheral surface of the frame body of the chuck table, a first movement blocking surface for blocking movement of each of the first pressing members in a direction approaching the rotation center, and the second A second movement preventing surface for preventing the pressing member from moving in a direction approaching the rotation center is formed, and each of the first pressing members corresponds to the first movement preventing surface. The first movement blocked surface is formed, and the second support frame is formed on the second support frame corresponding to the second movement blocked surface. Cutting equipment. Air ejecting means is provided that can eject air onto the holding upper surface of the chuck table and form an air layer between the semiconductor wafer placed on the holding upper surface and the holding upper surface. The cutting apparatus of any one of Claims 1-8.

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