JP4796382B2 - Chuck table of processing equipment - Google Patents

Description

  The present invention relates to a chuck table that holds a workpiece in a processing apparatus that processes the workpiece such as a semiconductor 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 streets to divide the region in which the device is formed to manufacture individual semiconductor chips. In addition, optical device wafers with gallium nitride compound semiconductors laminated on the surface of a sapphire substrate are also divided into individual optical devices such as light emitting diodes and laser diodes by cutting along the streets, and are widely used in electrical equipment. ing.

As a method of dividing the wafer such as the semiconductor wafer or the optical device wafer described above along the street, a laser processing groove is formed by irradiating a pulse laser beam along the street formed on the wafer, and along the laser processing groove. A method of breaking is proposed. (For example, refer to Patent Document 1.)
JP-A-10-305420

  When laser processing a wafer such as a semiconductor wafer, the wafer is held on a chuck table in a state of being adhered to the surface of an adhesive tape mounted on an annular frame in order to facilitate handling of the wafer. Then, a laser beam is irradiated along the street of the wafer held on the chuck table. However, when the wafer is irradiated with a laser beam, the wafer generates heat, and the adhesive tape formed of a synthetic resin such as polyolefin or polyethylene to which the wafer is attached is melted to generate toxic gas or divided chips. However, there is a problem that it cannot be peeled off firmly fixed to the adhesive tape. Further, even if the chip can be peeled off from the adhesive tape, there is a problem that a part of the molten adhesive tape adheres to the back surface of the chip and the quality of the chip is deteriorated.

  The present invention has been made in view of the above-mentioned fact, and the main technical problem thereof is a chuck table for a processing apparatus that can hold an adhesive tape to which a workpiece such as a wafer is attached so as not to melt. Is to provide.

In order to solve the above main technical problem, according to the present invention, there is provided a chuck table of a processing apparatus for holding a semiconductor wafer processed by a processing means via an adhesive tape attached to an annular frame , A plurality of holding portions each including a base portion, a plurality of columnar protrusions provided on a surface of the base portion and holding the semiconductor wafer with the adhesive tape interposed therebetween, and a periphery of the plurality of holding portions An outside air circulation part formed in the outside air, a suction hole that opens to the outside air circulation part and communicates with the suction means, and a coolant supply hole that opens to the outside air circulation part and communicates with the coolant supply means. The outside air is introduced into the outside air circulation part by the suction force acting on the suction hole, and the coolant supplied from the coolant supply hole to the outside air circulation part is evacuated by the outside air introduced into the outside air circulation part. And the heat of vaporization Allowed to cool said holding portion is provided a chuck table of a machining apparatus, characterized in that.

The suction hole is formed at the center of the base portion, and the coolant of the coolant supply means is coolant .

  According to the present invention, the coolant supplied to the outside air circulation part through the coolant supply hole is vaporized in contact with the outside air introduced into the outside air circulation part, and the holding part is cooled by the heat of vaporization. Therefore, the pressure-sensitive adhesive tape held by the holding portion and the workpiece attached to the pressure-sensitive adhesive tape are cooled, so that the pressure-sensitive adhesive tape does not melt.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of a chuck table of a processing apparatus configured according to the invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a perspective view of a laser processing apparatus as a processing apparatus equipped with a chuck table configured according to the present invention. A laser processing apparatus shown in FIG. 1 includes a stationary base 2, a chuck table mechanism 3 that is disposed on the stationary base 2 so as to be movable in a machining feed direction indicated by an arrow X, and holds a workpiece. The laser beam irradiation unit support mechanism 6 is movably arranged in an indexing direction indicated by an arrow Y perpendicular to the direction indicated by the arrow X in FIG. 2, and the laser beam unit support mechanism 6 moves in a focus position adjustment direction indicated by an arrow Z. And a laser beam irradiation unit 7 which can be arranged.

  The chuck table mechanism 3 includes a pair of guide rails 31, 31 arranged in parallel along the direction indicated by the arrow X on the stationary base 2, and the direction indicated by the arrow X on the guide rails 31, 31. A first sliding block 32 movably disposed, a second sliding block 33 movably disposed on the first sliding block 32 in a direction indicated by an arrow Y, and the second sliding block A cover table 35 supported by a cylindrical member 34 on the block 33 and a chuck table 4 as a workpiece holding means are provided.

  The first sliding block 32 is provided with a pair of guided grooves 321 and 321 fitted to the pair of guide rails 31 and 31 on the lower surface thereof, and along the direction indicated by the arrow Y on the upper surface thereof. A pair of guide rails 322 and 322 formed in parallel are provided. The first sliding block 32 configured as described above has the guided grooves 321 and 321 fitted into the pair of guide rails 31 and 31, thereby the direction indicated by the arrow X along the pair of guide rails 31 and 31. It is configured to be movable. The chuck table mechanism 3 in the illustrated embodiment includes a processing feed means 37 for moving the first sliding block 32 in the direction indicated by the arrow X along the pair of guide rails 31, 31. The processing feed means 37 includes a male screw rod 371 disposed in parallel between the pair of guide rails 31 and 31, and a drive source such as a pulse motor 372 for rotationally driving the male screw rod 371. One end of the male screw rod 371 is rotatably supported by a bearing block 373 fixed to the stationary base 2, and the other end is connected to the output shaft of the pulse motor 372 via a reduction gear (not shown). ing. The male screw rod 371 is screwed into a penetrating female screw hole formed in a female screw block (not shown) provided on the lower surface of the central portion of the first sliding block 32. Therefore, when the male screw rod 371 is driven to rotate forward and backward by the pulse motor 372, the first sliding block 32 is moved along the guide rails 31, 31 in the machining feed direction indicated by the arrow X.

  The second sliding block 33 is provided with a pair of guided grooves 331 and 331 which are fitted to a pair of guide rails 322 and 322 provided on the upper surface of the first sliding block 32 on the lower surface thereof. By fitting the guided grooves 331 and 331 to the pair of guide rails 322 and 322, the guided grooves 331 and 331 are configured to be movable in the direction indicated by the arrow Y. The chuck table mechanism 3 in the illustrated embodiment is a first for moving the second slide block 33 along the pair of guide rails 322 and 322 provided in the first slide block 32 in the direction indicated by the arrow Y. The indexing and feeding means 38 is provided. The first index feed means 38 includes a male screw rod 381 disposed in parallel between the pair of guide rails 322 and 322, and a drive source such as a pulse motor 382 for rotationally driving the male screw rod 381. It is out. One end of the male screw rod 381 is rotatably supported by a bearing block 383 fixed to the upper surface of the first sliding block 32, and the other end is connected to the output shaft of the pulse motor 382 via a reduction gear (not shown). Are connected. The male screw rod 381 is screwed into a penetrating female screw hole formed in a female screw block (not shown) provided on the lower surface of the central portion of the second sliding block 33. Therefore, when the male screw rod 381 is driven to rotate forward and reversely by the pulse motor 382, the second slide block 33 is moved along the guide rails 322 and 322 in the index feed direction indicated by the arrow Y.

Next, the chuck table 4 will be described with reference to FIGS.
The chuck table 4 shown in FIGS. 2 and 3 includes a cylindrical main body 41 formed of a metal material such as stainless steel as shown in FIG. 3 and a suction chuck portion 42 provided on the upper portion of the main body 41. A columnar main body 41 is rotatably supported by a cylindrical support cylinder 34 disposed on the upper surface of the second sliding block 33 via a bearing 340. The suction chuck portion 42 includes a plurality of holding portions 422 including a circular base portion 421 provided on the upper portion of the main body 41 and a holding surface 422a provided on the surface of the base portion 421 for holding a workpiece. An outside air circulation part 423 formed around the plurality of holding parts 422, a suction hole 424 formed in the center of the base part 421 and opening to the outside air circulation part 423, and an outer peripheral part of the base part 421. The plurality of coolant supply holes 425 are formed and open to the outside air circulation part 423. The height of the plurality of holding portions 422 is set to 0.5 to 1 mm. The suction hole 424 communicates with the suction means 43 through a suction passage 411 formed in the main body 41. The suction amount of the suction means 43 is set to 100 liters per minute (100 liters / minute) in the illustrated embodiment. The plurality of coolant supply holes 425 communicate with the coolant supply means 44 via a supply passage 412 formed in the main body 41. The coolant supply means 44 supplies cooling water in the illustrated embodiment. The supply amount of the coolant supply means 44 is set to 100 cc (100 cc / min) per minute in the illustrated embodiment.

  An annular groove 426 is formed in the suction chuck portion 42 constituting the chuck table 4. The bases of the four clamps 45 are disposed in the annular groove 426, and the bases of the clamps 45 and 45 are attached to the main body 41 by appropriate fixing means. A cover table 35 is disposed at the upper end of the support cylinder 34. The lower end of the main body 41 of the chuck table 4 configured as described above is connected to a pulse motor (not shown) disposed in the cylindrical member 34 and is appropriately rotated by the pulse motor.

  Referring back to FIG. 1, the laser beam irradiation unit support mechanism 6 includes a pair of guide rails 61 and 61 disposed on the stationary base 2 in parallel along the direction indicated by the arrow Y, and the guide A movable support base 62 is provided on the rails 61 and 61 so as to be movable in the direction indicated by the arrow Y. The movable support base 62 includes a movement support portion 621 that is movably disposed on the guide rails 61, 61, and a mounting portion 622 that is attached to the movement support portion 621. The mounting portion 622 is provided with a pair of guide rails 623 and 623 extending in the direction indicated by the arrow Z on one side surface in parallel. The laser beam irradiation unit support mechanism 6 in the illustrated embodiment includes a second index feed means 63 for moving the movable support base 62 along the pair of guide rails 61, 61 in the direction indicated by the arrow Y. Yes. The second index feed means 63 includes a male screw rod 631 disposed in parallel between the pair of guide rails 61, 61, and a drive source such as a pulse motor 632 for rotating the male screw rod 631. It is out. One end of the male screw rod 631 is rotatably supported by a bearing block (not shown) fixed to the stationary base 2 and the other end is connected to the output shaft of the pulse motor 632 via a reduction gear (not shown). Has been. The male screw rod 631 is screwed into a female screw hole formed in a female screw block (not shown) provided on the lower surface of the central portion of the moving support portion 621 constituting the movable support base 62. Therefore, when the male screw rod 631 is driven to rotate forward and reversely by the pulse motor 632, the movable support base 62 is moved along the guide rails 61 and 61 in the index feed direction indicated by the arrow Y.

  The laser beam irradiation unit 7 in the illustrated embodiment includes a unit holder 71 and laser beam irradiation means 72 attached to the unit holder 71. The unit holder 71 is provided with a pair of guided grooves 711 and 711 slidably fitted to a pair of guide rails 623 and 623 provided in the mounting portion 622. By being fitted to the guide rails 623 and 623, the guide rails 623 and 623 are supported so as to be movable in the direction indicated by the arrow Z.

  The illustrated laser beam application means 72 includes a cylindrical casing 721 that is fixed to the unit holder 71 and extends substantially horizontally. In the casing 721, a pulse laser beam oscillation means including a pulse laser beam oscillator composed of a YAG laser oscillator or a YVO4 laser oscillator and a repetition frequency setting means is disposed. A condenser 73 for condensing the laser beam oscillated from the pulse laser beam oscillation means is attached to the tip of the casing 721.

At the front end portion of the casing 721 constituting the laser beam irradiation means 72, an imaging means 8 for detecting a processing region to be laser processed by the laser beam irradiation means 72 is disposed. The imaging unit 8 includes an illuminating unit that illuminates the workpiece, an optical system that captures an area illuminated by the illuminating unit, an imaging device (CCD) that captures an image captured by the optical system, and the like. The captured image signal is sent to a control means (not shown).

  The laser beam irradiation unit 7 in the illustrated embodiment includes a moving means 74 for moving the unit holder 71 along the pair of guide rails 623 and 623 in the direction indicated by the arrow Z. The moving means 74 includes a male screw rod (not shown) disposed between the pair of guide rails 623 and 623, and a drive source such as a pulse motor 742 for rotationally driving the male screw rod. By driving the male screw rod (not shown) by the motor 742 in the forward or reverse direction, the unit holder 71 and the laser beam irradiation means 72 are moved in the direction indicated by the arrow Z along the pair of guide rails 623 and 623. In the illustrated embodiment, the laser beam irradiation means 72 is moved upward by driving the pulse motor 742 forward, and the laser beam irradiation means 72 is moved downward by driving the pulse motor 742 in the reverse direction. ing.

The laser processing apparatus in the illustrated embodiment is configured as described above, and the operation thereof will be described below.
Here, a semiconductor wafer as a workpiece to be laser processed by the laser processing apparatus will be described with reference to FIG. The semiconductor wafer 10 shown in FIG. 4 is made of a silicon wafer, and a plurality of devices 101 are formed in a matrix on the surface 10a. Each device 101 is partitioned by streets 102 formed in a lattice shape. The semiconductor wafer 10 has a back surface attached to an adhesive tape 12 mounted on an annular frame 11 with the front surface 10a as the processing surface facing upward. When processing the semiconductor wafer 10 from the back side, the front surface 10 a of the semiconductor wafer 10 is stuck to the adhesive tape 12. As the adhesive tape 12, for example, a tape in which an acrylic resin adhesive material is laid about 5 μm thick on the surface of a synthetic resin sheet such as polyolefin or polyethylene having a thickness of 100 μm is used.

  In order to irradiate a laser beam along the street 102 of the semiconductor wafer 10 and to form a laser processing groove along the street 102, the semiconductor wafer adhered to the surface of the adhesive tape 12 attached to the annular frame 11 is used. 10 is placed on the chucking chuck portion 42 of the chuck table 4 positioned at the workpiece loading / unloading position shown in FIG. Accordingly, the semiconductor wafer 10 is placed on the suction chuck portion 42 of the chuck table 4 via the adhesive tape 12 as shown in FIG. When the suction means 43 is operated, the air in the outside air circulation part 423 is sucked through the suction hole 424 and the suction passage 411. As a result, a negative pressure acts on the adhesive tape 12, and the adhesive tape 12 with the semiconductor wafer 10 attached is sucked and held on the holding surfaces 422 a of the plurality of holding portions 422 constituting the suction chuck portion 42. When air is sucked into the outside air circulation part 423 through the suction hole 424 and the suction passage 411, outside air is introduced into the outside air circulation part 423 from the surroundings, but the height of the plurality of holding parts 422 is 0.5 to 1 mm. Since the suction amount of the suction means 43 is large, the outside air circulation part 423 is maintained in a negative pressure state. Next, the annular frame 11 to which the adhesive tape 12 is attached is fixed by a clamp 45.

  As described above, the chuck table 4 that sucks and holds the semiconductor wafer 10 is positioned immediately below the imaging unit 8 by the processing feed unit 37. When the chuck table 4 is positioned immediately below the image pickup means 8, an alignment operation for detecting a processing region to be laser-processed of the semiconductor wafer 10 is executed by the image pickup means 8 and a control means (not shown). That is, the imaging unit 8 and a control unit (not shown) align the street 102 formed in a predetermined direction of the semiconductor wafer 10 and the condenser 724 of the laser beam irradiation unit 72 that irradiates the laser beam along the street 102. Image processing such as pattern matching is performed to perform alignment of the laser beam irradiation position. The alignment of the laser beam irradiation position is similarly performed on the street 102 formed on the semiconductor wafer 10 and extending at right angles to the predetermined direction.

  As described above, when the street 102 formed on the semiconductor wafer 10 held on the chuck table 4 is detected and the alignment of the laser beam irradiation position is performed, the chuck table 4 is moved and the position shown in FIG. ), One end (the left end in FIG. 5A) of the predetermined division line 102 is positioned directly below the condenser 73. Then, while irradiating a pulse laser beam having a wavelength of, for example, 355 nm, which absorbs the silicon wafer from the condenser 73, the chuck table 4 is moved in a direction indicated by an arrow X1 in FIG. Move it. Then, as shown in FIG. 5B, when the irradiation position of the condenser 73 reaches the position of the other end of the street 102, the irradiation of the pulse laser beam is stopped and the movement of the chuck table 4 is stopped. As a result, a laser processing groove 110 is formed along the street 102 as shown in FIG. 5B (laser beam irradiation step). In this laser beam irradiation step, the condensing point P of the pulse laser beam is matched with the vicinity of the surface 10 a (upper surface) of the semiconductor wafer 10. In this laser beam irradiation step, the coolant supply means 44 is operated to supply coolant to the outside air circulation part 423 through the supply passage 412 and the plurality of coolant supply holes 425.

In the illustrated embodiment, the processing conditions in the laser beam irradiation step are set as follows.
Light source: LD excitation Q switch Nd: YVO4 laser Laser wavelength: 355 nm pulse laser Pulse output: 14 μJ
Condensing spot diameter: φ13μm
Repetition frequency: 100 kHz
Processing feed rate: 100 mm / sec

  In the laser beam irradiation step described above, when the semiconductor wafer 10 is irradiated with a pulse laser beam, the semiconductor wafer 10 generates heat. When the semiconductor wafer 10 generates heat, the adhesive tape 12 to which the semiconductor wafer 10 is attached is melted because it is made of a synthetic resin such as polyolefin or polyethylene. However, in the illustrated embodiment, the coolant supply means 44 is operated as described above to supply the coolant to the outside air circulation part 423 through the supply passage 412 and the plurality of coolant supply holes 425. As described above, the cooling water supplied to the outside air circulation unit 423 is vaporized in contact with the outside air introduced into the outside air circulation unit 423, and the plurality of holding units 422 are cooled by the heat of vaporization. Therefore, since the adhesive tape 12 held by the plurality of holding portions 422 and the semiconductor wafer 10 attached to the adhesive tape 12 are cooled, the adhesive tape 12 does not melt.

  When the laser beam irradiation process is performed along the predetermined street 102 as described above, the chuck table 4 is indexed and fed by the interval of the street 102 in the direction indicated by the arrow Y in FIG. 1 (indexing process), and the laser beam irradiation process is performed. To implement. When the laser beam irradiation process and the indexing process are performed for all the streets 102 extending in a predetermined direction of the semiconductor wafer 10 in this manner, the chuck table 4 and thus the semiconductor wafer 2 held by the chuck table 4 are rotated 90 degrees. Then, by executing the laser beam irradiation step and the indexing step along each street 102 extending at right angles to the predetermined direction, the laser processing groove 110 can be formed along all the streets 102 of the semiconductor wafer 10. it can.

  When the laser processing grooves 110 are formed along all the streets 102 of the semiconductor wafer 10 as described above, the supply of the cooling water by the coolant supply means 44 is stopped, and the chuck table 4 is mounted on the substrate shown in FIG. Return to the workpiece loading / unloading position. Then, the operation of the suction means 43 is stopped and the suction holding of the semiconductor wafer 10 is released. Next, by releasing the fixation of the annular frame 11 by the clamp 45, the semiconductor wafer 10 is conveyed to the next division step while being held by the annular frame 11 via the adhesive tape 12. In the dividing step, the semiconductor wafer 10 is divided into individual semiconductor chips by applying an external force along the laser processing groove 110 formed in the semiconductor wafer 10. In this way, the semiconductor wafer 10 divided into individual semiconductor chips is conveyed to the next pickup process while being held by the annular frame 11 via the adhesive tape 12. In the pick-up process, the individually divided semiconductor chips are separated from the adhesive tape 12 and picked up. At this time, since the adhesive tape 12 is not melted as described above, it is easily separated from the adhesive tape 12, Part of the adhesive tape 12 does not adhere to the back surface of the semiconductor chip.

  As mentioned above, although this invention was demonstrated based on embodiment of illustration, this invention is not limited only to embodiment, A various deformation | transformation is possible in the range of the meaning of this invention. For example, in the illustrated embodiment, an example in which a plurality of holding portions 422 are formed by columnar protrusions is shown. However, an outside air circulation portion by radial grooves or lattice-like grooves is formed on the surface of the base portion 421 in the suction chuck portion 42. By forming, a holding part surrounded by an outside air circulation part may be formed.

The perspective view of the laser processing apparatus comprised according to this invention. The perspective view of the chuck table with which the laser processing apparatus shown in FIG. 1 is equipped. Sectional drawing of the chuck table shown in FIG. The perspective view which shows the state which affixed the semiconductor wafer as a to-be-processed object to the adhesive tape with which the cyclic | annular flame | frame was mounted | worn. Explanatory drawing of the laser beam irradiation process implemented by the laser processing apparatus shown in FIG.

Explanation of symbols

2: stationary base 3: chuck table mechanism 31, 31: a pair of guide rails 32: first sliding block 33: second sliding block 37: processing feeding means 38: first indexing feeding means 4: chuck table 41 : Chuck table main body 42: Adsorption chuck part 421: Base part 422: Holding part 423: Outside air inflow part 424: Suction hole 425: Coolant supply hole 43: Suction means 44: Coolant supply means 6: Laser beam irradiation unit support Mechanisms 61, 61: A pair of guide rails 62: Movable support base 63: Second index feed means 7: Laser beam irradiation unit 71: Unit holder 72: Laser beam irradiation means 73: Condenser 8: Imaging means 10: Semiconductor wafer 11: annular frame 12: adhesive tape

Claims (2)

A chuck table of a processing apparatus for holding a semiconductor wafer processed by a processing means via an adhesive tape attached to an annular frame ,
A plurality of holding portions each including a base portion, a plurality of columnar protrusions provided on a surface of the base portion and holding the semiconductor wafer with the adhesive tape interposed therebetween, and a periphery of the plurality of holding portions An outside air circulation part formed in the outside air, a suction hole that opens to the outside air circulation part and communicates with the suction means, and a coolant supply hole that opens to the outside air circulation part and communicates with the coolant supply means. Equipped,
Outside air is introduced into the outside air circulation part by the suction force acting on the suction hole, and the coolant supplied to the outside air circulation part is vaporized by the outside air introduced into the outside air circulation part, Cooling the holding part by heat of vaporization,
A chuck table for a processing apparatus. The chuck table of the processing apparatus according to claim 1, wherein the suction hole is formed in a central portion of the base portion, and the coolant of the coolant supply means is coolant .

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