JP2016004909A - Transport device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transport device capable of correcting a wafer into a flat state and normally holding the wafer on a chuck table without reinforcing a motor or a transport mechanism of the device when conveying a tabular workpiece of which the outer periphery is warped upwards, sucking and holding the workpiece on the chuck table.SOLUTION: In a transport device 70, a workpiece 11 is transported from a temporary placement table to a chuck table 50 and even a workpiece of which the outer peripheral part is warped upwards can be sucked and held on the chuck table 50. The transport device 70 includes: a holding unit 80 for holding the workpiece; movable means which moves between the temporary placement table and the chuck table; and a support part 86 which is drooped from an end portion of the movable means. The holding unit includes a disk-shaped support member 88 and an annular pressing pad 96. The annular pressing pad includes: a pressing part 98 which is formed annular from an elastic member for pressing the outer periphery of the workpiece; and a tapered drooping part 100 which extends downwards on an outer peripheral side surface of the pressing part, and is widened towards the radial outside and thinned as it becomes lower.

Description

  The present invention relates to a conveying apparatus capable of conveying a plate-shaped workpiece having warpage to a chuck table and sucking and holding the workpiece to the chuck table.

  In a manufacturing process of a semiconductor device or an optical device, a plurality of grid-like divisional lines called streets are formed on the surface of a semiconductor wafer or an optical device wafer, and a semiconductor device or an optical device is formed in each region partitioned by the divisional lines. It is formed.

  After these wafers are ground and thinned to a predetermined thickness, they are divided by a cutting device or a laser processing device along the planned dividing line, whereby individual semiconductor devices and optical devices are manufactured. The

  When grinding a plate-like workpiece such as a semiconductor wafer or optical device wafer, the front side of the wafer is sucked and held via a protective tape with a chuck table of a grinding machine, and a grinding wheel is applied to the back side of the wafer. Grinding is accomplished by sliding while touching and feeding the grinding wheel.

  In addition, when performing a cutting operation on a plate-like workpiece, by rotating and feeding the chuck table holding the plate-like workpiece at a predetermined processing feed speed while rotating the bite tool on a circular path, The surface of the plate-like workpiece held on the chuck table is turned by a turning tool with a bite tool to be flattened.

  However, some plate-like workpieces have warpage. For example, a wafer in which different materials such as a WL-CSP (Wafer Level-Chip Size Package) wafer are laminated has a large warpage. Some large-diameter wafers have large warpage.

  If the wafer is greatly warped, the holding surface of the chuck table is flat, which causes a problem that the wafer cannot be sucked and held by the chuck table. When the outer peripheral area of the wafer is warped upward, the outer peripheral area of the wafer is lifted, and the negative pressure leaks, so that the wafer cannot be held by the chuck table. Japanese Laid-Open Patent Publication Nos. 2005-109057 and 2006-019566 disclose a conveying device that can suck and hold such a warped wafer by a chuck table.

  The suction hand of the transfer device described in the above publication is provided with a suction pad that sucks only the central portion of the wafer, a plate that covers the upper portion of the wafer, and a pin that corresponds to the outer peripheral region of the wafer.

  In these suction hands, the wafer warped is corrected by pressing the wafer conveyed to the chuck table against the holding surface of the chuck table with a plate or a pin, and the wafer is sucked and held on the chuck table.

JP 2005-109057 A JP 2006-019566 A

  However, the conveying device is not originally intended to press the wafer against the chuck table, and in order to obtain a large pressing force, the motor for moving the conveying device up and down must be changed to a powerful one.

  In addition, in such a correction method, there is a problem that distortion occurs in the rail on which the conveying device is disposed and the frame that holds the rail due to the reaction force generated when the wafer is pressed against the chuck table.

  If such distortion repeatedly occurs in the mass production process, a failure may occur, and it is necessary to reinforce the distorted portion. If the parts of the apparatus are replaced or reinforced in order to cope with the above problems, there is a problem that the cost increases.

  The present invention has been made in view of the above points, and an object of the present invention is to convey a plate-like workpiece whose outer peripheral region is warped upward and suck and hold it on a chuck table. It is an object of the present invention to provide a transport device that can correct a wafer whose outer peripheral region warps upward without reinforcing a motor or a transport mechanism to a flat state and can be normally sucked and held by a chuck table.

  According to the present invention, a workpiece is conveyed from a temporary placement table for temporarily placing a plate-like workpiece to a chuck table having a holding surface, and a workpiece whose outer peripheral portion is warped upward as compared with the vicinity of the center is also chucked. A conveyance device that enables suction holding on a table, and moves a holding unit that holds a workpiece and the holding unit between the temporary table and the chuck table and also in a vertical direction. A moving unit; and a support unit that is suspended from an end of the moving unit and supports the holding unit. The holding unit includes a disk-like support member fixed to the support unit, and one end of the holding unit. A rod member inserted through the central portion of the support member so as to be movable at the tip of the support portion; a suction pad having a suction surface fixed to the other end of the rod member; the suction pad and the disc shape Branch A coil spring interposed between the members and biasing the suction pad downward, and an annular pressing pad disposed on the lower surface of the outer periphery of the disk-like support member, the annular pressing pad being an elastic member A pressing portion that has an outer diameter larger than the workpiece and an inner diameter smaller than the workpiece, and presses the outer peripheral area of the workpiece; and an outer periphery of the pressing portion that is formed in an annular shape by an elastic member A taper-shaped hanging portion that is disposed on a side surface, extends downward from the pressing portion, expands radially outward as it goes downward, and decreases in thickness. There is provided a transport device characterized in that the suction surface is movable between a protruding position where the suction surface protrudes below the pressing portion and a storage position where the suction surface does not protrude below the pressing portion.

  According to the conveying apparatus of the present invention, after the plate-like workpiece is conveyed and placed on the holding surface of the chuck table, the holding unit is further lowered and the outer peripheral area of the workpiece is pressed by the pressing portion of the pressing pad. In this case, the drooping portion comes into contact with the outer peripheral portion of the holding surface of the chuck table and presses the outer peripheral area of the workpiece, and is sealed in a region surrounded by the pressing portion, the drooping portion, the holding surface of the chuck table, and the workpiece. When the workpiece is sucked by the chuck table by forming a region and the sealed region becomes negative pressure, the warped workpiece comes into close contact with the holding surface of the chuck table and sucks and holds the workpiece having warpage. Can do.

It is a perspective view of the grinding device provided with the conveyance device of the present invention. It is a perspective view which shows a mode that a protective tape is stuck on the surface of a semiconductor wafer. It is sectional drawing of the state which is going to suck and hold the warped wafer with a chuck table. It is sectional drawing explaining the effect | action of the conveying apparatus which concerns on this invention embodiment (the 1). It is sectional drawing explaining the effect | action of a conveying apparatus (the 2). It is sectional drawing explaining the effect | action of a conveying apparatus (the 3).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, an external perspective view of a grinding device 2 provided with a transport device according to an embodiment of the present invention is shown. Reference numeral 4 denotes a base of the grinding apparatus, and two columns 6 a and 6 b are erected on the rear side of the base 4.

  A pair of guide rails 8 extending in the vertical direction is fixed to the column 6a. A rough grinding unit 10 is mounted along the pair of guide rails 8 so as to be movable in the vertical direction. The rough grinding unit 10 is attached to a moving base 12 whose housing 20 moves up and down along a pair of guide rails 8.

  The rough grinding unit 10 includes a housing 20, a spindle 22 rotatably accommodated in the housing 20, a servo motor accommodated in the housing 20 that rotationally drives the spindle 22, and a wheel mount fixed to the tip of the spindle. 24 and a grinding wheel 26 having a plurality of grinding wheels for rough grinding fixed to the wheel mount 24 in a detachable manner.

  The rough grinding unit 10 includes a rough grinding unit feed mechanism 18 including a ball screw 14 and a pulse motor 16 that move the rough grinding unit 10 up and down along a pair of guide rails 8. When the pulse motor 16 is driven, the ball screw 22 rotates and the moving base 12 is moved in the vertical direction.

  A pair of guide rails 28 extending in the vertical direction are also fixed to the other column 6b. A finish grinding unit 30 is mounted along the pair of guide rails 28 so as to be movable in the vertical direction.

  The finish grinding unit 30 is attached to a moving base 32 whose housing 40 moves in the vertical direction along a pair of guide rails 28. The finish grinding unit 30 includes a housing 40, a spindle 42 rotatably accommodated in the housing 40, a servo motor accommodated in the housing 40 that rotationally drives the spindle 42, and a wheel fixed to the tip of the spindle 42. A grinding wheel 46 having a mount 44 and a grinding wheel for finish grinding that is detachably fixed to the wheel mount 44 is included.

  The finish grinding unit 30 includes a finish grinding unit feed mechanism 38 including a ball screw 34 and a pulse motor 36 that move the finish grinding unit 30 in the vertical direction along a pair of guide rails 28. When the pulse motor 36 is driven, the ball screw 34 rotates and the finish grinding unit 30 is moved in the vertical direction.

  The grinding device 2 includes a turntable 48 disposed so as to be parallel to the upper surface of the base 4 on the front side of the columns 6a and 6b. The turntable 48 is formed in a relatively large-diameter disk shape, and is rotated in a direction indicated by an arrow 49 by a rotation drive mechanism (not shown).

  On the turntable 48, three chuck tables 50 are arranged so as to be rotatable in a horizontal plane, spaced from each other by 120 ° in the circumferential direction. The chuck table 50 has a holding portion formed in a disk shape by a porous ceramic material, and sucks and holds the wafer placed on the holding surface of the holding portion by operating a vacuum suction means.

  The three chuck tables 50 arranged on the turntable 48 are rotated in accordance with the rotation of the turntable 48, so that the wafer loading / unloading area A, rough grinding area B, finish grinding area C, and wafer loading / unloading are performed. The region A is sequentially moved.

  A cassette placement area 52 including two cassette placement stands 54 and 56 fixed to the base 4 is disposed in the front portion of the base 4. A cassette 58 that houses a wafer before grinding is placed on the cassette table 54, and a cassette 60 that houses a wafer after grinding is placed on the cassette table 56.

  As shown in FIG. 2, a plurality of planned dividing lines (streets) 13 are formed in a lattice shape on the surface of a semiconductor wafer (hereinafter, sometimes simply referred to as a wafer) 11. A device 15 such as an IC or LSI is formed in each of the areas. An orientation flat 17 indicating the crystal orientation of the wafer 11 is formed on the wafer 11.

  In performing back surface grinding of the wafer 11, in order to protect the device 15 formed on the surface, a surface protective tape 19 is attached to the surface of the wafer 11, and the protective tape 19 attached to the surface is directed downward. In this state, the wafer 11 is accommodated in the cassette 58.

  A recess 62 is formed in the base 4 adjacent to the cassette mounting area 52, and a wafer transfer robot 64 is disposed in the recess 62. A temporary placement table 66 for temporarily placing a wafer taken out from the cassette 58 by the wafer transfer robot 64 is disposed adjacent to the recess 62, and is placed on the temporary placement table 66 above the temporary placement table 66. An image pickup unit 68 for picking up an image of the wafer 11 is disposed.

  Reference numeral 70 denotes a transport device according to an embodiment of the present invention, which is a column 82 that can be moved up and down by an air cylinder or the like and that can be rotated by a motor, etc. And a holding unit 80 supported by the support portion 86.

  The transport device 70 sucks and holds the wafer 11 temporarily placed on the temporary placement table 66 by the holding unit 80 and transports the wafer 11 to the chuck table 50 positioned in the wafer carry-in / out region A. Further, the conveying device 70 sucks and holds the ground wafer from the chuck table 50 positioned in the wafer carry-in / out region A and conveys it to the spinner cleaning unit 72.

  The transport device 70 according to the embodiment of the present invention has a configuration that is particularly suitable for transporting the wafer 11 having warpage from the temporary placement table 66 to the chuck table 50 positioned in the wafer carry-in / out area A and holding it by suction. doing.

  A problem in holding the warped wafer 11 by the chuck table 50 will be described with reference to FIG. The chuck table 50 includes a plurality of suction grooves 74 that open to the holding surface 50a, and each suction groove 74 is connected to a suction source (not shown) via suction paths 76 and 78.

  When the suction path 76 of the chuck table 50 is connected to a suction source to try to suck and hold the warped wafer 11, the negative pressure at the portion where the wafer 11 is not in close contact with the holding surface 50 a of the chuck table 50 leaks, and the wafer is leaked. 11 cannot be sucked and held by the chuck table 50.

  When the wafer 11 is pressed by the pressing means and flattened with respect to the holding surface 50a of the chuck table 50, negative pressure does not leak from the holding surface 50a of the chuck table 50, so the wafer 11 is sucked and held by the chuck table 50. Can do.

  Hereinafter, with reference to FIG. 4 thru | or FIG. 6, the conveying apparatus 70 which concerns on embodiment of this invention is demonstrated in detail. As described above, the transfer device 70 includes the column 82 attached to the base 4 so as to be movable up and down and pivotable, the arm 84 attached to the upper end of the column 82, and the support hanging from the tip of the arm 84. Part 86 and holding unit 80 supported by support part 86.

  As shown in FIG. 4A, the holding unit 80 includes a disk-like support member 88 fixed to the tip of the support portion 86. One end of the rod member 90 passes through the center portion of the disc-like support member 88 and is inserted into the tip of the support portion 86 so as to be movable. A suction pad 92 having a suction surface 92a is attached to the other end of the rod member 90. It has been. A coil spring 94 that biases the suction pad 92 downward is interposed between the suction pad 92 and the disk-like support member 86.

  An annular pressing pad 96 is attached to the lower surface of the outer peripheral portion of the disc-like support member 88. The annular pressing pad 96 is formed in an annular shape by an elastic member such as rubber and has a pressing portion 98 having an outer diameter larger than the wafer 11 and an inner diameter smaller than the wafer 11, and an elastic member such as rubber made of a softer material than the pressing portion 98. A taper-shaped hanging part which is formed in an annular shape and is arranged on the outer peripheral side surface of the pressing part 98 and extends downward from the pressing part 98 and spreads radially outward as it goes downward. 100.

  The suction pad 92 is urged by the coil spring 94 so that the suction surface 92a protrudes below the pressing portion 98, and the suction pad 92a does not protrude below the pressing portion 98 and is accommodated as shown in FIG. It can move between positions.

  Hereinafter, the operation of the transfer device 70 will be described. As shown in FIG. 4A, the arm 84 of the transfer device 70 is rotated to position the holding unit 80 on the wafer 11 held on the temporary placement table 66.

  Next, as shown in FIG. 4B, the holding unit 80 is moved downward as indicated by the arrow Z <b> 1, and the suction pad 92 is pressed against the center portion of the wafer 11. Since the warpage is small at the center portion of the wafer 11, the wafer 11 can be sucked and held by the suction pad 92 after the suction of the temporary table 66 is released.

  With the wafer 11 being sucked and held by the suction pad 92, the holding unit 80 is moved in the direction of the arrow Y1, as shown in FIG. 5A, that is, the arm 84 is rotated and held by the suction pad 92. The wafer 11 is conveyed onto the chuck table 50 positioned in the wafer carry-in / carry-out area (A). Next, as shown in FIG. 5B, the holding unit 80 is moved downward as indicated by the arrow Z <b> 1 to place the wafer 11 on the chuck table 50.

  When the holding unit 80 is still moved downward, the coil spring 94 contracts and the upper end portion of the rod member 90 enters the support portion 86 as shown in FIG. At the same time, the pressing portion 98 of the annular pressing pad 96 contacts the outer peripheral portion of the wafer 11, and the annular hanging portion 100 contacts the outer peripheral portion of the holding surface 50 a of the chuck table 50. A sealed region 102 is formed between the wafer 11 and the holding surface 50 a of the chuck table 50.

  In this state, when the chuck table 50 is connected to the suction source and the suction path 76 is sucked as shown by the arrow A, a negative pressure acts on the suction groove 74 and the inside of the sealed region 102 becomes a negative pressure (negative pressure). Therefore, when the holding unit 80 is pressed in the direction of the arrow Z1, the wafer 11 can be flattened by pressing the outer peripheral portion of the wafer 11 with the pressing portion 98 with a pressing force that is not so large as shown in FIG. 6B. Even the wafer 11 having warpage can be sucked and held by the chuck table 50.

  When the arm 84 is raised after the suction of the suction pad 92 is released, the wafer 11 is in close contact with the holding surface 50a of the chuck table 50, so that the state where the wafer 11 is sucked and held by the chuck table 50 can be maintained. it can.

  After the wafer 11 is sucked and held by the chuck table 50 in this manner, the turntable 48 is rotated 120 ° to position the wafer 11 in the rough grinding region B, and the rough grinding unit 10 performs rough grinding of the wafer 11. After the rough grinding, the turntable 48 is further rotated by 120 ° to position the wafer 11 in the finish grinding region C, and the finish grinding of the wafer 11 is performed by the finish grinding unit 30.

  After the finish grinding is performed, the turntable 48 is further rotated 120 ° to position the chuck table 50 holding the wafer 11 in the wafer carry-in / out area A. Next, the arm 84 of the transfer device 70 is rotated to position the holding unit 80 on the wafer 11, and then the holding unit 80 is lowered, and the suction surface 92a of the suction pad 92 as shown in FIG. 4B. Is brought into contact with the wafer 11.

  After the suction and holding of the chuck table 50 is released, the wafer 11 is sucked by the suction pad 92, the arm 84 of the transfer device 70 is rotated, and the ground wafer 11 is transferred to the spinner cleaning unit 72, and the spinner cleaning unit. At 72, the wafer 11 is spin cleaned and spin dried.

  In the above-described embodiment, the example in which the conveyance device 70 is applied to the wafer 11 having a warp has been described, but the wafer 11 having no warp can of course be transported. Furthermore, the conveyance apparatus of the present invention can be similarly applied not only to the conveyance of the wafer but also to the conveyance of other plate-like workpieces such as the WL-CSP wafer.

  In the above description, an example in which the conveyance device 70 of the present invention is applied to a grinding device has been described. However, the present invention is not limited to this, and a chuck table for sucking and holding a plate-like workpiece such as a wafer is provided. The present invention can be similarly applied to processing devices such as a cutting device, a polishing device, a cutting tool, and a laser processing device.

DESCRIPTION OF SYMBOLS 10 Rough grinding unit 11 Semiconductor wafer 30 Finish grinding unit 48 Turntable 50 Chuck table 66 Temporary table 70 Transfer device 80 Holding unit 82 Column 84 Arm 86 Support part 88 Disc-shaped support member 90 Rod member 92 Adsorption pad 96 Annular press pad 98 Press part 100 Hanging part 102 Sealed area

Claims (1)

The work piece is transported from a temporary placement table for temporarily placing a plate-like work piece to a chuck table having a holding surface, and even a work piece whose outer peripheral portion is warped upward as compared with the vicinity of the center is sucked and held on the chuck table. A transfer device that enables
A holding unit for holding the workpiece;
Moving means for moving the holding unit between the temporary table and the chuck table and also moving in the vertical direction;
A support portion that hangs down from an end of the moving means and supports the holding unit,
The holding unit includes a disk-like support member fixed to the support portion;
A rod member having one end penetrating the central portion of the disc-shaped support member and movably inserted at the tip of the support portion;
A suction pad having a suction surface fixed to the other end of the rod member;
A coil spring interposed between the suction pad and the disk-like support member and biasing the suction pad downward;
An annular pressing pad disposed on the lower surface of the outer peripheral portion of the disk-shaped support member,
The annular pressing pad is formed in an annular shape by an elastic member, has a larger outer diameter than the workpiece and an inner diameter smaller than the workpiece, and a pressing portion that presses the outer peripheral region of the workpiece;
A tapered shape that is formed in an annular shape with an elastic member, is disposed on the outer peripheral side surface of the pressing portion, extends downward from the pressing portion, spreads radially outward as it goes downward, and becomes thinner. A hanging part,
The transport device, wherein the suction pad is movable between a protruding position where the suction surface protrudes below the pressing portion and a storage position where the suction surface does not protrude below the pressing portion.