CN105196162A - Conveying device - Google Patents

Abstract

The present invention provides a transfer device having: a holding unit that holds a workpiece; a moving unit that moves the holding unit between a temporary placement table and a chuck table and in a vertical direction; and The support part hangs down from the end of the mobile unit to support the holding unit. The holding unit includes: a disc-shaped support member, which is fixed to the support portion; and an annular pressing pad, which is arranged on the lower surface of the outer periphery of the disc-shaped supporting member, and the annular pressing pad has: a pressing portion, which is formed by an elastic member It is ring-shaped and presses the outer peripheral area of the workpiece; and a tapered drooping part is formed in a ring shape by an elastic member, arranged on the outer peripheral side of the pressing part, extends downward from the pressing part, and goes toward Expands radially outward and becomes thinner in thickness.

Description

Conveyor

technical field

The present invention relates to a conveying device capable of conveying a warped plate-shaped workpiece to a chuck table and capable of attracting and holding the workpiece on the chuck table.

Background technique

In the manufacturing process of semiconductor devices or optical devices, a plurality of grid-like dividing lines called spacers are formed on the front surface of the semiconductor wafer or optical device wafer, and semiconductor devices are formed on each area divided by the dividing lines. , Optical devices.

After the back surface of these wafers is ground and thinned to a predetermined thickness, they are divided along planned dividing lines by a cutting device or a laser processing device to manufacture individual semiconductor devices and optical devices.

When grinding a plate-shaped workpiece such as a semiconductor wafer or an optical device wafer, the front side of the wafer is sucked and held by the chuck table of the grinding device through a protective tape, and the grinding wheel is brought into contact with the back side of the wafer. Grinding is performed by sliding and grinding feed of the grinding wheel.

In addition, when cutting a plate-shaped workpiece with a tool, the chuck table holding the plate-shaped workpiece is processed at a predetermined machining feed rate while rotating the cutting tool along a circular orbit. In this way, the surface of the plate-shaped workpiece held on the chuck table is rotated and flattened by the cutting tool.

However, a plate-shaped workpiece may have warpage. For example, a wafer in which different materials are stacked, such as a WL-CSP (Wafer Level-Chip Size Package) wafer, may have large warpage. Also, a large-diameter wafer sometimes has a large warp.

When the wafer is greatly warped, there arises a problem that the wafer cannot be sucked and held by the chuck table because the holding surface of the chuck table is flat. When the outer peripheral region of the wafer is warped upward, the outer peripheral region of the wafer floats, and negative pressure leakage occurs, so that the wafer cannot be held by the chuck table. Japanese Patent Application Laid-Open No. 2005-109057 and Japanese Patent Laid-Open No. 2006-019566 disclose transfer devices capable of sucking and holding such warped wafers by using a chuck table.

The suction hand of the transfer device described in the above publication has: a suction pad that suctions only the central portion of the wafer; a plate that covers the upper portion of the wafer; or a pin that corresponds to the outer peripheral area of the wafer.

In these suction hands, the wafer conveyed to the chuck table is pressed against the holding surface of the chuck table with plates or pins to correct warpage of the wafer, and the wafer is sucked and held on the chuck table.

Existing patent documents

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2005-109057

Patent Document 2: Japanese Patent Laid-Open No. 2006-019566

Contents of the invention

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

In addition, in this correction method, there is a problem that the rail on which the transfer device is disposed or the frame holding the rail is deformed due to the reaction force generated when the wafer is pressed onto the chuck table.

In the mass production process, if such deformation occurs repeatedly in the device, there is a possibility of failure, and it is necessary to reinforce the deformed part. When parts of the device are replaced or reinforced in order to cope with the above-mentioned problems, there arises a problem of cost increase.

The present invention has been made in view of such a point, and its object is to provide a transfer device that does not reinforce the device when transferring a plate-shaped workpiece that is warped upward in the outer peripheral region and sucking and holding it on the chuck table. In the case of a motor or transfer mechanism, the wafer warped upward in the outer peripheral region can be corrected to a flat state, and can be normally sucked and held on the chuck table.

According to the present invention, there is provided a transfer device that transfers a workpiece from a temporary placing table on which a plate-shaped workpiece is temporarily placed to a chuck table having a holding surface, even if the outer peripheral part is warped upward from the vicinity of the center. The processed object can also be sucked and held by using the chuck table. The conveying device is characterized in that it has: a holding unit that holds the processed object; move with the chuck table and also move in the vertical direction; and a support part that hangs down from the end of the moving unit and supports the holding unit, and the holding unit includes: a disc-shaped support member fixed on The support part; a rod part, one end of which passes through the central part of the disc-shaped support part and is movably inserted into the end of the support part; an adsorption pad, which is fixed to the other end of the rod part, and has an adsorption surface; A coil spring is installed between the adsorption pad and the disc-shaped support member to apply force downward to the adsorption pad; and an annular pressing pad is arranged on the lower surface of the outer periphery of the disc-shaped support member, and The shaped pressing pad has: a pressing part formed into a ring shape by an elastic member, has an outer diameter larger than the workpiece and an inner diameter smaller than the workpiece, and presses the outer peripheral region of the workpiece; and a tapered drooping part, which It is formed in a ring shape by an elastic member, arranged on the outer peripheral side of the pressing part, extends downward from the pressing part, expands radially outward and becomes thinner as it goes downward, and can be placed between the protruding position and the receiving pad. The protruding position is a position where the suction surface protrudes downward from the pressing portion, and the storage position is a position where the suction surface does not protrude downward from the pressing portion.

Invention effect

According to the conveying device of the present invention, after the plate-shaped workpiece is conveyed and placed on the holding surface of the chuck table, when the holding unit is further lowered to press the outer peripheral region of the workpiece with the pressing portion of the pressing pad, The hanging part is in contact with the outer peripheral portion of the holding surface of the chuck table to press the pressing part of the outer peripheral area of the workpiece, the hanging part, the holding surface of the chuck table and the area surrounded by the workpiece to form a sealed area, When the workpiece is sucked by the chuck table, the closed area becomes a negative pressure, so that the warped workpiece is closely attached to the holding surface of the chuck table, and the warped workpiece can be sucked and held.

Description of drawings

Fig. 1 is a perspective view of a grinding machine provided with a conveying device of the present invention.

FIG. 2 is a perspective view showing a state where a protective tape is attached to the front surface of the semiconductor wafer.

Fig. 3 is a cross-sectional view showing a state where a warped wafer is to be sucked and held by a chuck table.

Fig. 4 is a cross-sectional view (Part 1) illustrating the operation of the conveying device according to the embodiment of the present invention.

Fig. 5 is a cross-sectional view (Part 2) for explaining the operation of the conveying device.

Fig. 6 is a cross-sectional view (Part 3) for explaining the operation of the conveying device.

Label description

10: Rough grinding unit; 11: Semiconductor wafer; 30: Fine grinding unit; 48: Turntable; 50: Chuck table; 66: Temporary placement table; 70: Transfer device; 80: Holding unit; 82: Column ; 84: arm; 86: supporting part; 88: disc-shaped supporting part; 90: rod part; 92: adsorption pad; 96: ring-shaped pressing pad; 98: pressing part;

Detailed ways

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIG. 1 , FIG. 1 shows an external perspective view of a grinding device 2 provided with a conveying device according to an embodiment of the present invention. Reference numeral 4 is the base of the grinding device, and two columns 6a, 6b are vertically arranged behind the base 4 .

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

The rough grinding unit 10 includes: a housing 20; a shaft 22, which is rotatably accommodated in the housing 20; a servo motor, which is accommodated in the housing 20, for rotating the drive shaft 22; a wheel assembly 24, which is fixed at the end of the shaft; and a grinding wheel 26 having a plurality of grinding tools for rough grinding, and the grinding tools are detachably fixed to the wheel assembly device 24 .

The rough grinding unit 10 has a rough grinding unit feeding mechanism 18 composed of a ball screw 14 that moves the rough grinding unit 10 in the up and down direction along the pair of guide rails 8 and a pulse. The motor 16 constitutes. When the pulse motor 16 is driven, the ball screw 14 rotates, and the moving base 12 moves up and down.

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

The casing 40 of the finish grinding unit 30 is attached to the moving base 32 which moves up and down along a pair of guide rails 28 . The fine grinding unit 30 comprises: a housing 40; a shaft 42, which is rotatably accommodated in the housing 40; a servo motor, which is accommodated in the housing 40, for rotating the drive shaft 42; a wheel assembly 44, which is fixed at the end of the shaft 42 ; and a grinding wheel 46 having a grinding wheel for fine grinding detachably fixed to the wheel mounting device 44 .

The fine grinding unit 30 has a fine grinding unit feeding mechanism 38 composed of a ball screw 34 that moves the fine grinding unit 30 in the up and down direction along the pair of rails 28 and a pulse. The motor 36 constitutes. When the pulse motor 36 is driven, the ball screw 34 rotates, and the finishing grinding unit 30 is moved to an up-down direction.

The grinding device 2 has a turntable 48 arranged in parallel with the upper surface of the base 4 on the front side of the columns 6a, 6b. The turntable 48 is formed in a disc shape with a relatively large diameter, and rotates in the direction indicated by an arrow 49 by a rotation drive mechanism not shown.

Three chuck tables 50 are disposed on the turntable 48 at a distance of 120° from each other in the circumferential direction, and the chuck tables 50 are rotatable in a horizontal plane. The chuck table 50 has a disc-shaped holding portion made of a porous ceramic material, and suction holds a wafer placed on the holding surface of the holding portion by operating a vacuum suction unit.

When the turntable 48 is properly rotated, the three chuck tables 50 arranged on the turntable 48 are sequentially moved to the wafer loading/unloading area A, the rough grinding area B, the finish grinding area C, and the wafer loading/unloading area A.

On the front side part of the base 4 , a cassette loading area 52 is arranged, and the cassette loading area 52 is constituted by two cassette loading stages 54 and 56 fixed to the base 4 . A cassette 58 for accommodating a wafer before grinding is placed on the cassette stage 54 , and a cassette 60 for accommodating a wafer after grinding is placed on the cassette stage 56 .

As shown in FIG. 2 , on the front surface of a semiconductor wafer (hereinafter, sometimes simply referred to as a wafer) 11, a plurality of planned dividing lines (separation roads) 13 are formed in a grid pattern, and a plurality of planned dividing lines 13 are formed on each area divided. Devices 15 such as IC (Integrated Circuit) and LSI (Large Scale Integration). On the wafer 11, an orientation plane 17 indicating the crystal orientation of the wafer 11 is formed.

In order to protect the device 15 formed on the front side when the backside grinding of the wafer 11 is carried out, a front side protection tape 19 is pasted on the front side of the wafer 11, and the wafer 11 is stored in a state where the protection tape 19 pasted on the front side faces downward. Inside box 58.

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

Reference numeral 70 is a conveying device according to an embodiment of the present invention, which includes a column 82 capable of moving up and down by a cylinder or the like and rotating by a motor, an arm 84 attached to the upper end of the column 82 , and a support portion 86 fixed to the end of the arm 84 And the holding unit 80 supported by the support portion 86 .

The transfer device 70 absorbs and holds the wafer 11 temporarily placed on the temporary placement table 66 by the holding unit 80 , and transfers the wafer 11 to the chuck table 50 positioned in the wafer loading/unloading area A. The transport device 70 also sucks and holds the ground wafer from the chuck table 50 located in the wafer loading and unloading area A, and transports the wafer to the spin cleaning unit 72 .

The transport device 70 according to the embodiment of the present invention has a structure particularly suitable for transporting a warped wafer 11 from the temporary placement table 66 to the chuck table 50 positioned in the wafer loading/unloading area A for sucking and holding.

Problems when the warped wafer 11 is held by the chuck table 50 will be described with reference to FIG. 3 . The chuck table 50 has a plurality of suction grooves 74 opened on the holding surface 50 a, and each suction groove 74 is connected to a suction source (not shown) via suction passages 76 and 78 .

When the suction passage 76 of the chuck table 50 is connected to the suction source to suction and hold the warped wafer 11, the negative pressure leaks from the part of the wafer 11 that is not in close contact with the holding surface 50a of the chuck table 50, and cannot The wafer 11 is sucked and held by the chuck table 50 .

When utilizing the pressing unit to press the wafer 11 to make it flat with respect to the holding surface 50a of the chuck table 50, since the negative pressure will not leak from the holding surface 50a of the chuck table 50, it can be sucked by the chuck table 50. Wafer 11 is held.

Hereinafter, the transport device 70 according to the 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: the column 82 mounted to be movable up and down and rotatable relative to the base 4; the arm 84 attached to the upper end of the column 82; the support portion 86 suspended from the end portion of the arm 84; And the holding unit 80 supported by the support portion 86 .

As shown in (A) of FIG. 4 , the holding unit 80 has a disc-shaped support member 88 fixed to an end of the support portion 86 . One end of the rod member 90 penetrates the center of the disc-shaped support member 88 and is movably inserted into the end of the support portion 86 , and the other end of the rod member 90 is attached with an adsorption pad 92 having an adsorption surface 92 a. A coil spring 94 for biasing the suction pad 92 downward is installed between the suction pad 92 and the disk-shaped support member 86 .

An annular pressing pad 96 is attached to the lower surface of the outer peripheral portion of the disk-shaped support member 88 . The ring-shaped pressing pad 96 is composed of a pressing portion 98 and a tapered hanging portion 100. The pressing portion 98 is formed into a ring shape by 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. The part 100 is formed in a ring shape by an elastic member such as rubber which is softer than the pressing part 98, is disposed on the outer peripheral side of the pressing part 98, and extends downward from the pressing part 98. Expands outward and becomes thinner in thickness.

The suction pad 92 can move between a protruding position where the suction pad 92 is urged by the coil spring 94 so that the suction surface 92 a protrudes downward from the pressing portion 98 , and a storage position where the suction surface 92 a protrudes downward. 92a is a position shown in FIG. 6(B) where it does not protrude downward from the pressing portion 98 .

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

Next, as shown in (B) of FIG. 4 , the holding unit 80 is moved downward as shown by the arrow Z1 to press the suction pad 92 to the center of the wafer 11 . Since the warpage is small in the central portion of the wafer 11 , the wafer 11 can be sucked and held by the suction pad 92 after the suction of the temporary placing table 66 is released.

In the state where the wafer 11 is sucked and held by the suction pad 92, as shown in FIG. On the chuck table 50 in the wafer loading and unloading area A. Next, as shown in (B) of FIG. 5 , the holding unit 80 is moved downward as shown by the arrow Z1 to place the wafer 11 on the chuck table 50 .

When the holding unit 80 is further moved downward, as shown in (A) of FIG. 6 , the upper end portion of the rod member 90 enters the support portion 86 while the coil spring 94 is shortened. At the same time, since the pressing portion 98 of the annular pressing pad 96 abuts against the outer peripheral portion of the wafer 11, and the annular drooping portion 100 abuts against the outer peripheral portion of the holding surface 50a of the chuck table 50, it hangs down in an annular shape. A sealed region 102 is formed between the portion 100 , the pressing portion 98 , 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 passage 76 is sucked as indicated by arrow A, negative pressure acts on the suction groove 74 to make the inside of the sealed area 102 a negative pressure. Therefore, when the holding unit 80 is pressed in the arrow Z1 direction, as shown in FIG. Since it is flat, even a warped wafer 11 can be sucked and held by the chuck table 50 .

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

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

After finish grinding is performed, the turntable 48 is further rotated by 120° to position the chuck table 50 holding the wafer 11 in the wafer loading and unloading 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 to bring the suction surface 92a of the suction pad 92 into contact with the wafer 11 as shown in FIG.

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

In the above-mentioned embodiment, the example in which the transfer device 70 is applied to the wafer 11 having warpage has been described, but it is of course possible to transfer the wafer 11 without warp. In addition, not only the transfer of wafers, but also the transfer device of the present invention can be similarly applied to the transfer of other plate-shaped workpieces such as WL-CSP wafers.

In the above description, an example in which the conveying device 70 of the present invention is applied to a grinding device has been described, but the present invention is not limited thereto, and can be similarly applied to a card having a function of attracting and holding a plate-shaped workpiece such as a wafer. Processing devices such as cutting devices, grinding devices, tool cutting devices, and laser processing devices for disc tables.

Claims (1)

1. A conveying device for conveying a workpiece from a temporary placing table on which a plate-shaped workpiece is temporarily placed to a chuck table having a holding surface, even for workpieces whose outer peripheral portion is warped upward compared to the vicinity of the center The workpiece can also be sucked and held by the chuck table, and the conveying device is characterized in that which has: holding unit, which holds the workpiece; a moving unit that moves the holding unit between the temporary placement table and the chuck table and also moves in a vertical direction; and a support portion that hangs down from the end of the mobile unit and supports the holding unit, The holding unit includes: a disc-shaped supporting part, which is fixed to the supporting part; a rod member, one end of which penetrates the central portion of the disc-shaped support member and is movably inserted into the end of the support portion; an adsorption pad, which is fixed on the other end of the rod part and has an adsorption surface; a coil spring, installed between the adsorption pad and the disc-shaped support member, to apply force downward to the adsorption pad; and an annular pressing pad arranged on the lower surface of the outer periphery of the disc-shaped supporting member, The ring-shaped pressing pad has: a pressing portion formed in a ring shape by an elastic member, has an outer diameter larger than the workpiece and an inner diameter smaller than the workpiece, and presses an outer peripheral region of the workpiece; and The tapered hanging part, which is formed in a ring shape by an elastic member, is arranged on the outer peripheral side of the pressing part, extends downward from the pressing part, expands radially outward and becomes thinner as it goes downward, The suction pad can move between a protruding position where the suction surface protrudes below the pressing portion and a storage position where the suction surface does not protrude downward from the pressing portion.