KR102214368B1 - Conveyance apparatus - Google Patents

Abstract

In the present invention, when a plate-shaped work piece whose outer circumferential region is curved upward is conveyed and held by suction on a chuck table, the wafer whose outer circumferential region is curved upward can be corrected in a flat state without reinforcing the motor or the conveying mechanism of the apparatus, It is an object of the present invention to provide a conveying device capable of being normally sucked and held on a chuck table.
As a conveying device that transports the workpiece from a temporary arrangement table for temporarily placing plate-shaped workpieces to a chuck table with a holding surface, and enables suction and maintenance of the workpiece even if the workpiece is bent upwards relative to the center of the outer circumference. , A holding unit for holding a workpiece, a moving means for moving the holding unit between the temporary arrangement table and the chuck table and moving in a vertical direction, and the holding unit by dropping from the end of the moving means It is equipped with a support part for supporting the unit. The holding unit includes a disk-shaped support member fixed to the support portion, and an annular pressing pad disposed on a lower surface of an outer circumferential portion of the disk-shaped supporting member, and the annular pressing pad is formed in an annular shape with an elastic member and an outer circumferential region of the workpiece A pressing part for pressing the pressure, and an elastic member formed in an annular shape and disposed on the outer circumferential side of the pressing part, extending downward from the pressing part, and expanding toward the outer side in the radial direction as it goes downward, and a tapered thickness becomes thinner It has a shape-shaped lower part.

Description

Conveying device {CONVEYANCE APPARATUS}

The present invention relates to a conveying apparatus capable of conveying a plate-shaped workpiece having a warp to a chuck table and being sucked and held by the chuck table.

In the manufacturing process of semiconductor devices or optical devices, a plurality of grid-like division scheduled lines called streets are formed on the surface of the semiconductor wafer or optical device wafer, and semiconductor devices and optical devices are formed in each region divided by the division scheduled lines. Is formed.

The back surface of these wafers is ground to be thinned to a predetermined thickness, and then divided along a line to be divided by a cutting device or a laser processing device, so that individual semiconductor devices and optical devices are manufactured.

When grinding a plate-shaped workpiece such as a semiconductor wafer or an optical device wafer, the chuck table of the grinding device is used to suction and hold the surface side of the wafer through a protective tape, and slide the grinding wheel into contact with the back surface of the wafer. The grinding is carried out by feeding the grinding wheel, grinding.

In addition, when performing bite cutting on a plate-shaped workpiece, the plate-shaped workpiece held in the chuck table is processed and transported at a predetermined processing feed rate while rotating the bite tool in a circular orbit. The surface of the tool is turned and cut with a bite tool to planarize it.

However, some plate-shaped workpieces have warp, and some have a large warp in wafers stacked with different materials such as a WL-CSP (Wafer Level-Chip Size Package) wafer. In addition, even large-diameter wafers may have a large warp.

If the wafer is bent largely, the holding surface of the chuck table is flat, and thus a problem that the wafer cannot be sucked and held by the chuck table occurs. When the outer circumferential region of the wafer is bent upward, the outer circumferential region of the wafer is lifted, negative pressure leaks, and the wafer cannot be held by the chuck table. A transfer device capable of holding such a curved wafer by suction with a chuck table is disclosed in Japanese Patent Laid-Open No. 2005-109057 and Japanese Patent Laid-Open No. 2006-019566.

The suction hand of the transfer apparatus described in the above publication is provided with a suction pad for suctioning only a central portion of the wafer, and a plate covering an upper portion of the wafer or a pin corresponding to the outer circumference of the wafer.

In these suction hands, the wafer conveyed to the chuck table is pushed against the holding surface of the chuck table with a plate or pin to correct the warp of the wafer, and the wafer is sucked and held by the chuck table.

Japanese Patent Publication No. 2005-109057 Japanese Patent Publication No. 2006-019566

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

In addition, in such a calibration method, there is a problem that a warp occurs in the rail on which the transfer device is disposed or the frame holding the rail due to the reaction force generated when the wafer is pressed against the chuck table.

If such distortion occurs repeatedly in the device during the mass production process, there is a risk of failure, and reinforcement of the distorted portion is required. In order to cope with the above problems, there arises a problem that costs increase when parts of the device are replaced or reinforced.

The present invention has been made in view of these points, and its object is to carry out a plate-shaped workpiece with an upwardly curved outer circumferential region to be sucked and held by the chuck table, without reinforcing the motor or the transport mechanism of the device, and It is to provide a conveying device capable of correcting a wafer whose area is bent upwards in a flat state, and capable of normally suctioning and holding a chuck table.

According to the present invention, a workpiece is transported from a temporary placement table for temporarily placing a plate-shaped workpiece to a chuck table having a holding surface, and suction and maintenance in the chuck table is possible even if the workpiece is bent upward with respect to the center of the outer circumference. A conveying device for holding a workpiece, a moving unit for moving the holding unit between the temporary arrangement table and the chuck table and moving in a vertical direction, and a dropping from the end of the moving unit ( And a support portion for supporting the holding unit in a recessed manner, wherein the holding unit has a disk-shaped support member fixed to the support portion, and one end penetrates the central portion of the disk-shaped support member and is inserted so as to be movable to the tip end of the support portion. A suction pad having a fixed rod member and a suction surface fixed to the other end of the rod member, a coil spring interposed between the suction pad and the disk-shaped support member and pressing the suction pad downward, and the disk-shaped support member An annular pressing pad disposed on a lower surface of the outer circumferential portion, wherein the annular pressing pad is formed in an annular shape with an elastic member and has an outer diameter larger than that of the workpiece and an inner diameter smaller than that of the workpiece, and presses an outer peripheral region of the workpiece; It is formed in an annular shape with an elastic member, is disposed on the outer circumferential side of the pressing unit, extends downward from the pressing unit, widens outward in the radial direction as it goes downward, and has a tapered lower portion that becomes thinner in thickness. ), wherein the adsorption pad is movable between a protruding position in which the adsorption surface protrudes downward from the pressing part and a receiving position in which the adsorption surface does not protrude downward than the pressing part. do.

According to the conveying apparatus of the present invention, when the plate-shaped workpiece is transported and placed on the holding surface of the chuck table, when the holding unit is further lowered and the outer circumferential region of the workpiece is pressed with the pressing portion of the pressing pad, the lower part of the chuck table When a sealed area is formed in the area surrounded by the holding surface of the chuck table, the holding surface of the chuck table and the pressing part that presses the outer circumferential area of the workpiece by contacting the outer circumference of the workpiece, and suctioning the workpiece with the chuck table. The sealed area becomes negative pressure so that the curved workpiece is in close contact with the holding surface of the chuck table, so that the workpiece having the warp can be sucked and maintained.

1 is a perspective view of a grinding apparatus provided with a conveying apparatus of the present invention.
2 is a perspective view showing a state in which a protective tape is adhered to the surface of a semiconductor wafer.
3 is a cross-sectional view of a state in which a bent wafer is being sucked and held by a chuck table.
4 is a cross-sectional view illustrating the operation of the conveying device according to the embodiment of the present invention (No. 1).
5 is a cross-sectional view illustrating the operation of the conveying device (No. 2).
6 is a cross-sectional view illustrating the operation of the conveying device (No. 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 with a conveying device according to an embodiment of the present invention is shown. Reference numeral 4 denotes a base of the grinding device, and two columns 6a and 6b are erected and installed behind the base 4.

A pair of guide rails 8 extending in the vertical direction is fixed to the column 6a. Along the pair of guide rails 8, the roughing unit 10 is mounted so as to be movable in the vertical direction. The roughing unit 10 is attached to a moving base 12 in which the housing 20 moves in the vertical direction along a pair of guide rails 8.

The roughing unit 10 includes a housing 20, a spindle 22 rotatably accommodated in the housing 20, a servo motor accommodated in the housing 20 for rotationally driving the spindle 22, and a front end of the spindle. It includes a fixed wheel mount 24 and a grinding wheel 26 having a plurality of grinding grindstones for roughing that are detachably fixed to the wheel mount 24.

The roughing unit 10 includes a roughing unit transfer mechanism 18 composed of a ball screw 14 and a pulse motor 16 for moving the roughing unit 10 in the vertical direction along a pair of guide rails 8. We have. When the pulse motor 16 is driven, the ball screw 14 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. Along the pair of guide rails 28, the finish grinding unit 30 is mounted 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 for rotationally driving the spindle 42, and a spindle 42. ) And a grinding wheel 46 having a grinding wheel for finish grinding that is fixed to the wheel mount 44 so as to be detachably attached to the wheel mount 44.

The finish grinding unit 30 includes a ball screw 34 and a pulse motor 36 for moving the finish grinding unit 30 in the vertical direction along a pair of guide rails 28 ( 38). 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 is provided with a turntable 48 arranged 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 disk shape of a relatively large diameter, and is rotated in the direction indicated by 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, separated by 120° from each other in the circumferential direction. The chuck table 50 has a holding portion formed of a porous ceramic material in a disk shape, and holds a wafer disposed on the holding surface of the holding portion by operating a vacuum suction means.

The three chuck tables 50 arranged on the turntable 48, when the turntable 48 rotates appropriately, the wafer loading/unloading area (A), the roughing processing area (B), the finish grinding processing area (C), and It is sequentially moved to the wafer loading/unloading area A.

In the front part of the base 4, a cassette placement area 52 is provided, which consists of two cassette placement tables 54 and 56 fixed to the base 4. On the cassette mounting table 54, a cassette 58 for accommodating the wafer before grinding is disposed, and on the cassette mounting table 56, a cassette 60 for accommodating the wafer after grinding is disposed.

As shown in Fig. 2, on the surface of the semiconductor wafer (hereinafter, sometimes abbreviated simply as a wafer) 11, a plurality of scheduled division lines (streets) 13 are formed in a lattice shape, and Devices 15 such as ICs and LSIs are formed in each area divided by (13). An orientation flat 17 indicating a crystal orientation of the wafer 11 is formed on the wafer 11.

When performing the backside grinding of the wafer 11, in order to protect the device 15 formed on the surface, a surface protection tape 19 is adhered to the surface of the wafer 11, and the protection tape 19 adhered to the surface. The wafer 11 is accommodated in the cassette 58 in the state of being turned down.

A concave portion 62 is formed in the base 4 adjacent to the cassette placement area 52, and a wafer transfer robot 64 is disposed in the concave portion 62. Adjacent to the concave portion 62, a temporary placement table 66 for temporarily placing wafers taken out from the cassette 58 by the wafer transfer robot 64 is disposed, and above the temporary placement table 66 An imaging unit 68 for imaging the wafer 11 placed on the placement table 66 is disposed.

Reference numeral 70 denotes a conveying device according to an embodiment of the present invention, a column 82 that can be moved up and down by an air cylinder or the like and rotatable by a motor, etc., an arm 84 attached to the upper end of the column 82, and an arm It includes a support portion 86 fixed to the tip of 84, and a holding unit 80 supported by the support portion 86.

The transfer device 70 sucks and holds the wafers 11 temporarily disposed on the temporary placement table 66 by the holding unit 80 to reach the chuck table 50 positioned in the wafer carrying/unloading area A. The wafer 11 is transported. The transfer device 70 also sucks and holds the ground wafer from the chuck table 50 positioned in the wafer carry-in/carry-out area A and transfers it to the spinner cleaning unit 72.

The conveying apparatus 70 of the embodiment of the present invention conveys the wafer 11 having warp from the temporary placement table 66 to the chuck table 50 positioned in the wafer loading/unloading area A, and suction is maintained. It has a configuration that is particularly suitable for making.

A problem in holding the curved wafer 11 on the chuck table 50 will be described with reference to FIG. 3. The chuck table 50 has a plurality of suction grooves 74 that open on its holding surface 50a, and each suction groove 74 is connected to a suction source (not shown) through suction paths 76 and 78. Has been.

When the suction path 76 of the chuck table 50 is connected to the suction source to suction and hold the wafer 11 having warpage, the wafer 11 is not in close contact with the holding surface 50a of the chuck table 50. Negative pressure leaks from the non-removable portion, and the wafer 11 cannot be sucked and held by the chuck table 50.

When the wafer 11 is pressed with a pressing means to make it flat against the holding surface 50a of the chuck table 50, since negative pressure does not leak from the holding surface 50a of the chuck table 50, the chuck table ( 50) can hold the wafer 11 by suction.

Hereinafter, a conveying device 70 according to an embodiment of the present invention will be described in detail with reference to FIGS. 4 to 6. As described above, the conveying device 70 includes a column 82 attached to the base 4 so as to move up and down and pivotable, an arm 84 attached to the upper end of the column 82, and an arm 84. ), and a holding unit 80 supported by the support part 86 and a support part 86 that is dropped from the distal end thereof.

As shown in FIG. 4A, the holding unit 80 is provided with a disk-shaped support member 88 fixed to the tip end of the support portion 86. One end of the rod member 90 penetrates the central portion of the disk-shaped support member 88 and is inserted so as to be movable to the tip end of the support part 86, and the other end of the rod member 90 has a suction surface 92a. Pad 92 is attached. A coil spring 94 for pressing the suction pad 92 downward is interposed between the suction pad 92 and the disk-shaped support member 88.

An annular pressing pad 96 is attached to the lower surface of the outer peripheral portion of the disc-shaped support member 88. The annular pressing pad 96 is formed in an annular shape with an elastic member such as rubber, and has an outer diameter larger than the wafer 11 and an inner diameter smaller than the wafer 11, and a material softer than the pressing portion 98 It is formed in an annular shape with an elastic member such as rubber and is disposed on the outer circumferential side of the pressing part 98 and extends downward from the pressing part 98, and as it goes downward, it expands toward the outside in the radial direction, and the thickness is thin. The paper is composed of a tapered lower portion 100.

The suction pad 92 is pressed by the coil spring 94 so that the suction surface 92a protrudes downward from the pressing portion 98, and the suction surface 92a is pushed downward from the pressing portion 98. It is movable between the receiving positions shown in Fig. 6(b) that do not protrude.

Hereinafter, the operation of the conveyance 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 by the temporary placement table 66.

Subsequently, as shown in FIG. 4B, the holding unit 80 is moved downward indicated by the arrow Z1, and the suction pad 92 is pressed against the central portion of the wafer 11. Since the warp is small in the central portion of the wafer 11, the wafer 11 can be sucked and held with the suction pad 92 after the temporary placement table 66 is released from suction.

In the state where the wafer 11 is sucked and held by the suction pad 92, the holding unit 80 is moved in the direction of arrow Y1, that is, the arm 84 is rotated, as shown in Fig. 5A. The wafer 11 held by the suction pad 92 is transferred onto the chuck table 50 positioned in the wafer carrying/unloading area A. Next, as shown in FIG. 5B, the holding unit 80 is moved downward indicated by the arrow Z1, and the wafer 11 is placed on the chuck table 50.

When the holding unit 80 is further moved downward, as shown in FIG. 6A, the coil spring 94 is reduced and the upper end of the rod member 90 enters the support 86. At the same time, since the pressing portion 98 of the annular pressing pad 96 contacts the outer circumferential portion of the wafer 11, and the annular lowering portion 100 contacts the outer circumferential portion of the holding surface 50a of the chuck table 50. , A sealed region 102 is formed between the annular lower portion 100 and the pressing portion 98 and the holding surface 50a of the wafer 11 and the chuck table 50.

In this state, when the chuck table 50 is connected to the suction source and the suction furnace 76 is sucked as indicated by arrow A, a negative pressure acts on the suction groove 74 and the negative pressure (negative pressure) in the sealed region 102 is reduced. do. Therefore, when the holding unit 80 is pushed in the direction of the arrow Z1, as shown in Fig. 6(b), the outer circumferential portion of the wafer 11 is pressed with the pressing unit 98 even with a small pressing force. Since the wafer 11 can be straightened flat, 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. ) Can be kept in a suction state.

After the wafer 11 is suction-held by the chuck table 50 in this way, the turntable 48 is rotated 120° to position the wafer 11 in the roughing processing area B, and the wafer 11 is placed in the roughing processing area B. Perform the roughing of 11). After roughing, the turntable 48 is further rotated 120° to position the wafer 11 in the finish grinding processing region C, and the finish grinding unit 30 performs finish grinding of the wafer 11.

After finishing grinding, the turntable 48 is further rotated by 120° to position the chuck table 50 holding the wafer 11 in the wafer carrying/unloading area A. Subsequently, 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, as shown in FIG. 4B. Similarly, the suction surface 92a of the suction pad 92 is brought into contact with the wafer 11.

After releasing the suction and holding of the chuck table 50, the wafer 11 is sucked with the suction pad 92, and the arm 84 of the transfer device 70 is rotated to remove the wafer 11 after grinding with a spinner cleaning unit. It is conveyed to 72, and the wafer 11 is spin cleaned and spin dried with a spinner cleaning unit 72.

In the above-described embodiment, an example in which the transfer device 70 is applied to the wafer 11 having warpage has been described, but of course, even the wafer 11 having no warpage can be transferred. In addition, not only the transfer of the wafer, but also the transfer of other plate-like workpieces such as WL-CSP wafers, the transfer apparatus of the present invention can be applied in the same manner.

In the above description, an example in which the conveyance device 70 of the present invention is applied to a grinding device is described, but the present invention is not limited to this, and a cutting with a chuck table for suction and holding a plate-shaped workpiece such as a wafer The same can be applied to processing devices such as a device, a polishing device, a cutting device, and a laser processing device.

10: roughing unit 11: semiconductor wafer
30: finish grinding unit 48: turntable
50: chuck table 66: temporary placement table
70: conveying device 80: holding unit
82: column 84: arm
86: support part 88: disc-shaped support member
90: rod member 92: suction pad
96: annular compression pad 98: compression portion
100: lower part 102: confined area

Claims (1)

As a conveying device that transports the workpiece from a temporary arrangement table for temporarily placing plate-shaped workpieces to a chuck table with a holding surface, and enables suction and maintenance of the workpiece even if the workpiece is bent upwards relative to the center of the outer circumference. ,
A holding unit that holds the workpiece,
A moving means for moving the holding unit between the temporary placement table and the chuck table, and moving the holding unit in a vertical direction,
And a support portion for supporting the holding unit by dropping from the end of the moving means,
The holding unit, a disk-shaped support member fixed to the support portion,
A rod member whose one end penetrates the central portion of the disk-shaped support member and is movably inserted to the tip end of the support portion;
An adsorption pad having an adsorption surface fixed to the other end of the rod member,
A coil spring interposed between the suction pad and the disk-shaped support member and urge the suction pad downward;
And an annular pressing pad disposed on a lower surface of the outer peripheral portion of the disk-shaped support member,
The annular pressing pad is formed in an annular shape with an elastic member and has an outer diameter larger than that of the workpiece and an inner diameter smaller than that of the workpiece, and presses an outer peripheral region of the workpiece;
It is formed in an annular shape with an elastic member, is disposed on the outer circumferential side of the pressing unit, extends downward from the pressing unit, widens outward in the radial direction as it goes downward, and has a tapered lower portion that becomes thinner in thickness. ),
The suction pad is movable between a protruding position in which the suction surface protrudes downward from the pressing part and a receiving position in which the suction surface does not protrude downward than the pressing part.

Images