JP2009010160A - Cutter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutter capable of suppressing vibrations in a chuck table. <P>SOLUTION: The cutter has a chuck-table mechanism with the chuck table holding a work and a supporting base supporting the chuck table and a cutting means with a cutting blade cutting the work held to the chuck table. In the cutter, a vibration damping means is fitted to the chuck table. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cutting apparatus for cutting a workpiece such as a semiconductor wafer or an optical device wafer.

  In the semiconductor device manufacturing process, a plurality of regions are partitioned by dividing lines called streets arranged in a lattice pattern on the surface of a substantially wafer-shaped semiconductor wafer, and devices such as ICs, LSIs, etc. are partitioned in the partitioned regions. Form. Then, the semiconductor wafer is cut along the planned dividing line to divide the region where the device is formed to manufacture individual semiconductor chips. In addition, optical device wafers in which gallium nitride compound semiconductors are stacked on the surface of sapphire substrates are also cut into optical devices such as individual light emitting diodes, laser diodes, CCDs, etc. Widely used.

The above-described cutting along the wafer street is usually performed by a cutting device. This cutting apparatus includes a chuck table having a holding surface for holding a workpiece such as a wafer, a cutting means having a cutting blade for cutting the workpiece held on the chuck table, and the chuck table and the cutting table. A cutting feed means for moving the means relative to each other; and a cutting feed means for moving the cutting means in a direction perpendicular to the holding surface of the chuck table. The cutting means includes a spindle unit having a rotary spindle, a cutting blade mounted on the rotary spindle, and a driving means for driving the rotary spindle to rotate. In such a cutting apparatus, the cutting blade is cut and fed by a predetermined amount while the cutting blade is rotated at a rotational speed of 20000 to 40000 rpm, and then the workpiece held on the cutting blade and the chuck table is relatively cut and fed. To do. (For example, refer to Patent Document 1.)
JP 2004-142086 A

  In the above-described cutting apparatus, vibrations from the cutting blade rotating at high speed may be transmitted to the chuck table via the workpiece, and the chuck table may resonate. As a result, when the thickness of a workpiece such as a wafer becomes as thin as 100 μm or less, there is a problem in that chipping occurs on the cut surface and the quality of the device is lowered. Further, in the case of a wafer having an adhesive film called a die attach film on the back surface, chipping occurs on the cut surface even if the thickness is about 300 μm. Such a phenomenon remarkably appears in a so-called two-spindle cutting apparatus in which two cutting means are provided and the workpiece held on the chuck table by two cutting blades is cut simultaneously.

  The present invention has been made in view of the above-described facts, and a main technical problem thereof is to provide a cutting apparatus capable of suppressing vibration of the chuck table.

In order to solve the above main technical problem, according to the present invention, a chuck table mechanism having a chuck table for holding a workpiece and a support base for supporting the chuck table, and a workpiece held on the chuck table. In a cutting apparatus comprising a cutting means including a cutting blade for cutting an object,
The chuck table is provided with vibration damping means.
A cutting device is provided.

  The chuck table includes a suction holding portion that is provided on the upper surface and sucks and holds a workpiece, and a supported portion that is provided at the center of the lower surface and is supported by the support base. The vibration damping means is the chuck table. It is arrange | positioned in the area | region surrounding the to-be-supported part in the lower surface of this. The vibration damping means is composed of a vibration damping member having a natural frequency different from that of the chuck table, and a viscoelastic adhesive that joins the vibration damping member to the lower surface of the chuck table. The viscoelastic adhesive desirably has a hardness of 60 or less Shore hardness.

  According to the cutting apparatus of the present invention, the chuck table is provided with the vibration damping means, so that the vibration due to the rotation of the cutting blade is transmitted to the chuck table via the workpiece when cutting by the cutting blade. The vibration transmitted to is attenuated by the vibration damping means. Therefore, since the chuck table does not resonate, the vibration of the work piece held on the chuck table is suppressed, so that chips generated on the cut surface can be reduced.

  Hereinafter, a preferred embodiment of a cutting device configured according to the present invention will be described in more detail with reference to the accompanying drawings.

  FIG. 1 shows a perspective view of a cutting device constructed in accordance with the present invention. 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 mechanism 3 for holding a workpiece is disposed so as to be movable in a direction indicated by an arrow X that is a cutting feed direction. The chuck table mechanism 3 will be described with reference to FIG.

  The chuck table mechanism 3 in the illustrated embodiment includes a chuck table 4 that holds a workpiece and a support base 5 that supports the chuck table 4. The chuck table 4 is formed in a disc shape by a metal material such as stainless steel, and is provided on the upper surface and sucked and held by a work holding base 41 provided on the lower surface and supported by the support base 5. The supported portion 42 is provided. A circular fitting recess 411 is formed in the suction holding portion 41, and an annular mounting shelf 412 is provided on the outer periphery of the bottom surface of the fitting recess 411. Then, a suction chuck 413 formed of a porous member made of porous ceramics or the like having countless suction holes is fitted into the fitting recess 411. Further, the chuck table 4 is provided with a communication passage 43 that opens to the fitting recess 411 and opens to the supported portion 42. The chuck table 4 thus configured is provided with vibration damping means 44 in a region surrounding the supported portion 42 on the lower surface. The vibration damping means 44 includes a vibration damping member 441 made of a ceramic plate having a natural frequency different from that of the chuck table 4 in the illustrated embodiment, and a viscoelastic adhesive 442 that joins the vibration damping member 441 to the lower surface of the chuck table 4. It has become. The viscoelastic adhesive 442 preferably has a Shore hardness of 60 or less, and a rubber adhesive such as urethane can be used.

  The support base 5 is formed in a columnar shape by a metal material such as stainless steel, and includes a support portion 51 that supports the supported portion 42 of the chuck table 4 on the upper surface. An annular groove 511 is provided. The support base 5 is formed with a suction passage 52 communicating with the communication passage 43 provided in the chuck table 4 and a suction passage 53 communicating with an annular groove 511 provided in the support portion 51. . The suction passage 52 and the suction passage 53 are connected to the suction means 6. The suction means 6 includes a suction source 61, suction pipes 62 and 63 connecting the suction source 61, the suction passage 52 and the suction passage 53, and normally closed electromagnetic on-off valves provided with the suction pipes 62 and 63, respectively. 64 and 65. Therefore, when the supported portion 42 of the chuck table 4 is placed on the support portion 51 of the support base 5 and the electromagnetic on-off valve 65 is energized (ON), the suction pipe 63, the suction passage 53 and the annular shape are drawn from the suction source 61. Negative pressure acts on the support portion 51 through the groove 511, and the chuck table 4 is sucked and held on the support portion 51 of the support base 5. Further, when the electromagnetic opening / closing valve 64 is energized (ON), negative pressure acts on the fitting recess 411 of the chuck table 4 from the suction source 61 through the suction pipe 62, the suction passage 52, and the communication passage 43. A negative pressure is applied to the holding surface, which is the upper surface of the suction chuck 413 provided with suction holes. Further, a clamp support portion 54 is provided on the upper portion of the support base 5 so as to protrude in the radial direction, and four clamps 7 are attached to the upper surface of the clamp support portion 54 by appropriate fixing means. The support base 5 configured as described above is configured to be rotated by a rotation drive mechanism (not shown).

  The chuck table mechanism 3 in the illustrated embodiment includes a cover table 8 that covers the lower periphery of the chuck table 4. The cover table 8 has an opening 81 formed in the center, and a flange portion 82 that protrudes upward is provided on the periphery of the opening 81. This flange portion 82 is positioned inside a skirt portion 541 formed at the lower end portion of the clamp support portion 54 of the chuck table 4. The cover table 8 configured in this manner is supported in the state shown in FIG. 2 by a support member (not shown).

  Referring back to FIG. 1, the description continues, and the cutting apparatus in the illustrated embodiment includes a spindle unit 9 as a cutting means for cutting a workpiece held on the chuck table 4 of the chuck table mechanism 3. . The spindle unit 9 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 an arrow Z that is a cutting direction. The rotary spindle 92 is supported, and a cutting blade 93 is mounted on the front end of the rotary spindle 92. The spindle unit 9 as the cutting means configured as described above is moved in the index feed direction indicated by an arrow Y in FIG. 1 by an index feed means (not shown), and indicated by an arrow Z in FIG. 1 by a notch feed means (not shown). It can be moved in the cutting feed direction.

  The cutting apparatus in the illustrated embodiment includes an image pickup means 11 for picking up an image of the surface of the workpiece held on the chuck table 4 and detecting a region to be cut by the cutting blade 93. The imaging means 11 is composed of optical means such as a microscope and a CCD camera. In addition, the cutting apparatus includes a display unit 12 that displays an image captured by the imaging unit 11.

  In the cassette mounting area 13a of the apparatus housing 2, a cassette mounting table 13 for mounting a cassette for storing a workpiece is disposed. The cassette mounting table 13 is configured to be movable in the vertical direction by lifting means (not shown). On the cassette mounting table 13, a cassette 14 for storing a wafer W as a workpiece is placed. The wafer W accommodated in the cassette 14 is, for example, a semiconductor wafer. A lattice-like street is formed on the surface of a silicon substrate, and devices are formed in a plurality of rectangular regions partitioned by the lattice-like street. The wafer W formed in this way is accommodated in the cassette 14 with the back surface adhered to the front surface of the protective tape T mounted on the annular frame F.

  Further, the cutting device in the illustrated embodiment shows a wafer W (supported on the annular frame F via the protective tape T) accommodated in the cassette 14 placed on the cassette placement table 13. Unloading / loading means 16 for unloading the wafer after cutting into the temporary placement table 15 and loading the wafer W into the cassette 14, and first transfer means for transferring the wafer W unloaded to the temporary setting table 15 onto the chuck table 4. 17, a cleaning unit 18 that cleans the wafer W cut on the chuck table 4, and a second transport unit 19 that transports the workpiece W cut on the chuck table 4 to the cleaning unit 18. is doing.

The cutting apparatus in the illustrated embodiment is configured as described above, and the operation thereof will be described below mainly with reference to FIG.
The wafer W accommodated in a predetermined position of the cassette 14 placed on the cassette placement table 13 is positioned at the carry-out position by the vertical movement of the cassette placement table 13 by a lifting means (not shown). Next, the unloading / loading means 16 moves forward and backward to unload the wafer W positioned at the unloading position onto the temporary table 15. The wafer W carried out to the temporary placement table 15 is transported onto the suction chuck 413 of the chuck table 4 by the turning motion of the first transport means 17. When the wafer 10 is placed on the chucking chuck 413 of the chuck table 4, the electromagnetic on-off valve 64 of the suction means 6 shown in FIG. 2 is energized (ON). When the electromagnetic on-off valve 64 is energized (ON), negative pressure acts on the fitting recess 411 of the chuck table 4 from the suction source 61 through the suction pipe 62, the suction passage 52, and the communication passage 43 as described above, and innumerable A negative pressure is applied to the holding surface, which is the upper surface of the suction chuck 413 having the suction holes. As a result, the wafer W placed on the suction chuck 413 of the chuck table 4 is sucked and held on the suction chuck 413. The annular frame F that supports the wafer W via the protective tape T is fixed by the clamp 7. The chuck table 4 holding the wafer W in this way is moved to a position immediately below the image pickup means 11. When the chuck table 4 is positioned immediately below the image pickup means 11, the street formed on the wafer W is detected by the image pickup means 11, and the spindle unit 9 is moved and adjusted in the arrow Y direction as the indexing direction to adjust the street and the cutting blade. A precision alignment operation with 93 is performed.

  Thereafter, the cutting blade 93 is cut and fed by a predetermined amount in the direction indicated by the arrow Z in FIG. 1, and the chuck table 4 which holds the wafer W by suction while rotating the cutting blade 93 in the direction indicated by the arrow 93a as shown in FIG. Is cut and fed in the direction indicated by the arrow X1, the wafer W held on the chuck table 4 is cut along a predetermined street by the cutting blade 93. At the time of cutting with the cutting blade 93, vibration due to the rotation of the cutting blade 93 is transmitted to the chuck table 4 via the wafer W. The vibration transmitted to the chuck table 4 is damped by vibration damping means 44 disposed on the lower surface of the chuck table 4. That is, the vibration damping means 44 includes a vibration damping member 441 made of a ceramic plate having a different natural frequency from the chuck table 4 and a viscoelastic adhesive 442 that joins the vibration damping member 441 to the lower surface of the chuck table 4. The vibration transmitted to the chuck table 4 is damped by the difference in natural frequency and the vibration damping characteristic by the viscoelastic adhesive 442. Therefore, since the chuck table 4 does not resonate, the vibration of the wafer W held on the chuck table 4 is suppressed, so that chips generated on the cut surface can be reduced.

  When the wafer W is cut along a predetermined street as described above, the chuck table 4 is indexed and fed in the direction indicated by the arrow Y in FIG. 1 to perform the cutting operation. If the cutting operation is performed along all the streets extending in the predetermined direction of the wafer W, the chuck table 4 is rotated by 90 degrees so that the streets extending in the direction perpendicular to the predetermined direction of the wafer W are obtained. By performing the cutting operation along the entire path, all the streets formed in a lattice shape on the wafer W are cut and divided into individual devices. The divided devices do not fall apart due to the action of the protective tape T, and the state of the wafer supported by the annular frame F is maintained.

  Next, the chuck table 4 holding the wafer W is first returned to the position where the wafer W is sucked and held. Then, the suction holding of the wafer W is released. Next, the wafer W is transferred to the cleaning unit 18 by the second transfer unit 19. The wafer W conveyed to the cleaning means 18 is cleaned and dried here. The wafer W cleaned and dried in this way is carried out to the temporary placement table 15 by the first transport means 17. Then, the wafer W is stored in a predetermined position of the cassette 114 by the carry-out / carry-in means 16.

  As mentioned above, although the example which applied this invention to the cutting device provided with the one cutting means was shown, two cutting means are arrange | positioned and the workpiece hold | maintained at the chuck table by two cutting blades is cut simultaneously. If the present invention is applied to a so-called two-spindle cutting apparatus configured as described above, the above-described effects become remarkable.

The perspective view of the cutting device comprised according to this invention. FIG. 2 is a cross-sectional view of a main part of a chuck table mechanism equipped in the cutting apparatus shown in FIG. Explanatory drawing which shows the cutting operation state of the cutting device shown in FIG.

Explanation of symbols

2: device housing 3: chuck table mechanism 4: chuck table 41: chuck table suction holding unit 413: suction chuck 42: chuck table supported portion 44: vibration damping means 441: damping member 442: viscoelastic adhesive 5 : Support base 51: support part of support base 6: suction means 61: suction source 62, 63: suction pipe 64, 65: electromagnetic on-off valve 7: clamp 8: cover table 9: spindle unit 91: spindle housing 92: Rotating spindle 93: Cutting blade 11: Imaging means 12: Display means 13: Cassette placing table 14: Cassette 15: Temporary placing table 16: Unloading / carrying means 17: First conveying means 18: Cleaning means 19: Second Transport means

Claims (4)

A chuck table mechanism having a chuck table for holding a workpiece and a support base for supporting the chuck table; and a cutting means having a cutting blade for cutting the workpiece held on the chuck table. In the cutting device to
The chuck table is provided with vibration damping means.
The cutting device characterized by the above. The chuck table includes a suction holding portion that is provided on the upper surface and sucks and holds a workpiece, and a supported portion that is provided at the center of the lower surface and is supported by the support base.
The cutting apparatus according to claim 1, wherein the vibration damping means is disposed in a region surrounding the supported portion on the lower surface of the chuck table.   3. The cutting apparatus according to claim 2, wherein the vibration attenuating means comprises a vibration damping plate having a natural frequency different from that of the chuck table, and a viscoelastic adhesive that joins the vibration damping plate to the lower surface of the chuck table.   The cutting apparatus according to claim 3, wherein the viscoelastic adhesive has a hardness set to a Shore hardness of 60 or less.

Images