JP7747533B2 - Grinding equipment - Google Patents

Description

The present invention relates to a grinding device.

In a grinding device, a plate-shaped object held by suction on the holding surface of the porous member of the chuck table is ground with a grinding wheel, and grinding chips are discharged. Therefore, the holding surface sucks in grinding chips from the outer periphery of the plate-shaped object held by suction. The sucked-in grinding chips are also sucked in by the outer periphery of the holding surface and remain on the outer periphery of the holding surface, reducing the suction force on the outer periphery of the holding surface and thinning the thickness of the outer periphery of the plate-shaped object.

To prevent this decline in the suction force of the holding surface, self-grinding is performed periodically to grind the holding surface and remove grinding debris from the outer periphery of the holding surface. However, grinding debris generated when grinding the holding surface by self-grinding can enter the porous member, and after self-grinding, grinding debris can become trapped between the holding surface and the underside of the plate-like object being held by the holding surface. This can cause the plate-like object to become thin in parts or develop cross-shaped cracks.

The technology disclosed in Patent Document 1 therefore includes a cover with an area that covers the holding surface, and while the cover is covering the holding surface, two fluids, water and air, are sprayed from the holding surface to remove grinding debris from the holding surface and the porous material that makes up the holding surface.

JP 2015-060922 A

However, the technology in Patent Document 1 requires a cover that covers the holding surface and a mechanism for moving the cover, which makes the device larger.

Therefore, the object of the present invention is to prevent grinding chips from getting between the holding surface and the underside of the plate-like object by discharging the grinding chips from the holding surface and the porous member that makes up the holding surface, without increasing the size of the device, and to grind the plate-like object to a uniform thickness.

The grinding device of the present invention (the present grinding device) is a grinding device comprising: a chuck table that suction-holds a plate-like object with a holding surface of a porous member; a grinding mechanism that grinds the plate-like object suction-held by the holding surface with a grinding wheel; a carry-in mechanism that holds the plate-like object and carries it into the holding surface; a carry-out mechanism that holds the plate-like object and carries it out of the holding surface; and a control unit, and further comprises an underside cleaning mechanism that cleans the underside of the plate-like object held by the carry-out mechanism or the carry-in mechanism, and the control unit controls the suction-holding of the plate-like object on the holding surface and the carry-out mechanism or the carry-in mechanism to clean the underside of the plate-like object. The holding surface holds the plate-like object by suction, and two fluids, a mixture of water and air, are ejected from the holding surface while the plate-like object is covering it . After the two fluids are ejected from the holding surface, the underside of the plate-like object separated from the holding surface is cleaned by the underside cleaning mechanism, the holding surface is again covered with the plate-like object, and the two fluids are ejected from the holding surface. The two fluids ejected from the holding surface flow outward in the diameter direction of the holding surface between the holding surface and the plate-like object, removing grinding chips from the porous member and the holding surface.

In this grinding device, by passing two fluids through the porous member while the holding surface is covered with a plate-like object, grinding chips that have entered the porous member from the holding surface can be expelled from the porous member and the holding surface. This prevents grinding chips from getting between the holding surface and the workpiece during grinding using the grinding mechanism, making it possible to grind the workpiece to a uniform thickness.

In addition, this grinding device uses an existing discharge mechanism or load mechanism to discharge grinding chips from the porous member and holding surface. Therefore, the amount of additional components required for discharging grinding chips can be reduced, making it possible to discharge grinding chips without increasing the size of the grinding device.

FIG. 2 is a perspective view showing the configuration of a grinding device. FIG. 4 is an explanatory diagram showing a first holding step and a second holding step. FIG. 10 is an explanatory diagram showing a fluid jetting process. FIG. 10 is an explanatory diagram showing a lower surface cleaning step. 10A and 10B are explanatory diagrams showing modified examples of pads of the ejection mechanism.

As shown in FIG. 1, the grinding apparatus 1 according to this embodiment is an apparatus for grinding a wafer 100, which is an example of a workpiece. The wafer 100 is, for example, a circular, plate-shaped workpiece, and has a front surface 101 and a back surface 102. The back surface 102 of the wafer 100 is the surface to be ground. The wafer 100 also functions as a plate-shaped object used to remove grinding debris from the porous member 21 and the holding surface 22.

The grinding device 1 has a first device base 10 and a second device base 11 located behind the first device base 10 (on the +Y direction side).

A first cassette stage 160 and a second cassette stage 162 are provided on the -Y direction side of the first equipment base 10. A first cassette 161 containing unprocessed wafers 100 is placed on the first cassette stage 160. A second cassette 163 containing processed wafers 100 is placed on the second cassette stage 162.

The first cassette 161 and the second cassette 163 each have multiple shelves inside, with one wafer 100 stored on each shelf. In other words, the first cassette 161 and the second cassette 163 store multiple wafers 100 in a shelf-like manner.

The openings (not shown) of the first cassette 161 and the second cassette 163 face in the +Y direction. A robot 155 is disposed on the +Y direction side of these openings. The robot 155 has a holding surface for holding the wafers 100. The robot 155 transports (stores) the processed wafers 100 into the second cassette 163. The robot 155 also removes the unprocessed wafers 100 from the first cassette 161 and places them on the temporary placement table 154 of the temporary placement mechanism 152.

The temporary placement mechanism 152 is used to temporarily place the wafers 100 removed from the first cassette 161, and is located adjacent to the robot 155. The temporary placement mechanism 152 has a temporary placement table 154 and an alignment member 153. The alignment member 153 has multiple alignment pins arranged on the outside to surround the temporary placement table 154, and a slider that moves the alignment pins in the radial direction of the temporary placement table 154. In the alignment member 153, the alignment pins are moved radially toward the center of the temporary placement table 154, thereby reducing the diameter of the circle connecting the multiple alignment pins. As a result, the wafer 100 placed on the temporary placement table 154 is aligned (centered) to a predetermined position where the center of the temporary placement table 154 and the center of the wafer 100 coincide.

A carry-in mechanism 170 is provided adjacent to the temporary placement mechanism 152. The carry-in mechanism 170 holds the wafer 100 temporarily placed on the temporary placement mechanism 152 and carries it onto the holding surface 22 of the chuck table 20 for placement.

The chuck table 20 is an example of a holding member that holds the wafer 100, and has a holding surface 22 that holds the wafer 100 by suction. The holding surface 22 is connected to a suction source 47 (see Figure 2) and is capable of holding the wafer 100 by suction. With the wafer 100 held by the holding surface 22, the chuck table 20 can rotate around a central axis that passes through the center of the holding surface 22 and extends in the Z-axis direction.

In this embodiment, two chuck tables 20 are arranged on a circle centered at the center of the turntable 6 on the upper surface of the turntable 6, which is arranged on the second device base 11. A rotation shaft (not shown) for rotating the turntable 6 is arranged at the center of the turntable 6. This rotation shaft allows the turntable 6 to rotate about an axis extending in the Z-axis direction. As the turntable 6 rotates, the two chuck tables 20 revolve. This allows the chuck tables 20 to be positioned near the temporary placement mechanism 152 and below the grinding mechanism 70.

In addition, a column 15 is erected on the +Y direction side of the second device base 11. A grinding mechanism 70 for grinding the wafer 100 and a grinding feed mechanism 60 are provided in front of the column 15.

The grinding feed mechanism 60 moves the chuck table 20 and the grinding wheel 77 of the grinding mechanism 70 relative to each other in the Z-axis direction (grinding feed direction) perpendicular to the holding surface 22. In this embodiment, the grinding feed mechanism 60 is configured to move the grinding wheel 77 in the Z-axis direction relative to the chuck table 20.

The grinding feed mechanism 60 includes a pair of Z-axis guide rails 61 parallel to the Z-axis direction, a Z-axis moving table 63 that slides on the Z-axis guide rails 61, a Z-axis ball screw 62 parallel to the Z-axis guide rails 61, a Z-axis motor 64, and a holder 66 attached to the Z-axis moving table 63. The holder 66 supports the grinding mechanism 70.

The Z-axis moving table 63 is slidably mounted on the Z-axis guide rail 61. A nut (not shown) is fixed to the Z-axis moving table 63. A Z-axis ball screw 62 is threadedly engaged with this nut. The Z-axis motor 64 is connected to one end of the Z-axis ball screw 62.

In the grinding feed mechanism 60, the Z-axis motor 64 rotates the Z-axis ball screw 62, causing the Z-axis moving table 63 to move in the Z-axis direction along the Z-axis guide rail 61. As a result, the holder 66 attached to the Z-axis moving table 63 and the grinding mechanism 70 supported by the holder 66 also move in the Z-axis direction together with the Z-axis moving table 63.

The grinding mechanism 70 uses a grinding wheel 77 to grind the wafer 100 held by suction on the holding surface 22 of the chuck table 20. The grinding mechanism 70 includes a spindle housing 71 fixed to the holder 66, a spindle 72 rotatably held in the spindle housing 71, a spindle motor 73 that rotates the spindle 72, a wheel mount 74 attached to the lower end of the spindle 72, and a grinding wheel 75 supported by the wheel mount 74.

The spindle housing 71 is held by the holder 66 so as to extend in the Z-axis direction. The spindle 72 extends in the Z-axis direction perpendicular to the holding surface 22 of the chuck table 20 and is rotatably supported by the spindle housing 71.

The spindle motor 73 is connected to the upper end of the spindle 72. This spindle motor 73 rotates the spindle 72 around a rotation axis extending in the Z-axis direction.

The wheel mount 74 is disk-shaped and fixed to the lower end (tip) of the spindle 72. The wheel mount 74 supports the grinding wheel 75.

The grinding wheel 75 is formed so that its outer diameter is approximately the same as the outer diameter of the wheel mount 74. The grinding wheel 75 includes an annular wheel base 76 made of a metal material. A plurality of grinding stones 77 are fixed to the underside of the wheel base 76, arranged in an annular pattern, around the entire circumference. The grinding stones 77 are rotated around their center by the spindle motor 73 together with the spindle 72, and grind the back surface 102 of the wafer 100 held on the chuck table 20.

After grinding, the wafer 100 is removed by the removal mechanism 172. The removal mechanism 172 holds the wafer 100 held on the holding surface 22 of the chuck table 20 and removes it from the holding surface 22. The removal mechanism 172 transports the wafer 100 removed from the holding surface 22 to the spinner table 157 of the single-wafer spinner cleaning mechanism 156. The configuration of the removal mechanism 172 will be described later.

The spinner cleaning mechanism 156 is a spinner cleaning unit that cleans the wafer 100. The spinner cleaning mechanism 156 includes a spinner table 157 that holds the wafer 100, and a nozzle 158 that sprays cleaning water and dry air toward the spinner table 157.

In the spinner cleaning mechanism 156, the spinner table 157 holding the wafer 100 rotates while cleaning water is sprayed toward the wafer 100, thereby spin-cleaning the wafer 100. Dry air is then blown onto the wafer 100 to dry it.

The wafer 100 cleaned by the spinner cleaning mechanism 156 is transferred by the robot 155 to the second cassette 163 on the second cassette stage 162.

In addition, a lower surface cleaning mechanism 180 is disposed between the turntable 6 and the spinner cleaning mechanism 156. The lower surface cleaning mechanism 180 is used to clean the front surface 101, which is the lower surface of the wafer 100 that is transported from the chuck table 20 to the spinner cleaning mechanism 156 by the unloading mechanism 172. In other words, the lower surface cleaning mechanism 180 cleans the front surface 101 of the wafer 100 held by the unloading mechanism 172.

Here, the configuration of the chuck table 20 will be described.
2 , the chuck table 20 is a circular plate-shaped table for holding the wafer 100. The chuck table 20 includes a circular plate-shaped porous member 21 and a frame 23 that supports the porous member 21. The porous member 21 can be connected to a suction source 47. The suction force from the suction source 47 is transmitted to a holding surface 22, which is the upper surface of the porous member 21, so that the chuck table 20 can suction-hold the wafer 100 using the holding surface 22 of the porous member 21.

The chuck table 20 is also rotatable by a rotation mechanism 30. The rotation mechanism 30 is, for example, a pulley mechanism, and includes a motor 31 as a drive source, a driving pulley 32 attached to the shaft of the motor 31, a driven pulley 34 connected to the driving pulley 32 via an endless belt 33, and a rotation shaft 35 that supports the driven pulley 34.

The rotating shaft 35 is connected to the underside of the chuck table 20 directly below the center of the holding surface 22 and extends perpendicular to the holding surface 22 of the chuck table 20. The motor 31 drives the driving pulley 32 to rotate, causing the endless belt 33 to rotate in conjunction with the rotation of the driving pulley 32. The rotation of the endless belt 33 causes the driven pulley 34 and the rotating shaft 35 to rotate. This causes the chuck table 20 to rotate around the center of the holding surface 22.

The grinding device 1 also includes a fluid flow mechanism 40. The fluid flow mechanism 40 is a mechanism for supplying a fluid such as air or water to the holding surface 22 of the chuck table 20, or for applying suction force to the holding surface 22.

The fluid flow mechanism 40 includes a suction groove 403, a suction flow path 470 connected to the suction groove 403, a rotary joint 460 connected to the rotary shaft 35, and a suction pipe 471 connected to the suction flow path 470.

The suction groove 403 is provided on the bottom surface of the recess in the frame 23 of the chuck table 20 so as to contact the underside of the porous member 21. The suction groove 403 is formed concentrically around the center of the chuck table 20.

The suction channel 470 extends from the bottom surface of the suction groove 403, passing through the frame 23, the rotary shaft 35, and the rotary joint 460.

The suction flow path 470 is connected to a suction pipe 471 outside the rotary joint 460. One end of the suction pipe 471 is connected to the suction flow path 470. The other end of the suction pipe 471 is connected to a suction source 47. This suction source 47 includes, for example, an ejector mechanism or a vacuum generator, and is connected to the porous member 21 of the chuck table 20 to apply suction force to the holding surface 22, which is the upper surface of the porous member 21.

Furthermore, a suction on-off valve 475 and a suction flow rate adjuster 473 are disposed in the suction pipe 471, in this order from the suction source 47 toward the suction flow path 470. The suction on-off valve 475 switches the communication state between the suction pipe 471 and the suction source 47. The suction flow rate adjuster 473 is, for example, a proportional control valve, and is used to change the internal orifice diameter when the suction on-off valve 475 is open to adjust the suction force transmitted from the suction source 47 to the holding surface 22 of the porous member 21.
The suction flow rate adjusting unit 473 may be a needle valve or a gate valve that manually adjusts the orifice diameter.

Furthermore, the suction pipe 471 is connected to an air pipe 481. The air pipe 481 is a pipe that connects the holding surface 22 of the chuck table 20 to the air supply source 48.

One end of the air pipe 481 is connected to the suction flow path 470 via the suction pipe 471. The other end of the air pipe 481 is connected to the air supply source 48. The air supply source 48 includes a compressor or the like and is used to supply air to the holding surface 22 of the chuck table 20.

Furthermore, an air supply on-off valve 485 and an air adjustment unit 483 are disposed in this order in the air pipe 481 from the air supply source 48 toward the suction flow path 470. The air supply on-off valve 485 switches the communication state between the air pipe 481 and the air supply source 48. The air adjustment unit 483 is, for example, a proportional control valve, and is used to change the internal orifice diameter to adjust the flow rate of air sent from the air supply source 48 to the holding surface 22 when the air supply on-off valve 485 is open.
The air adjusting unit 483 may be a needle valve or a gate valve that manually adjusts the orifice diameter.

The air pipe 481 is also provided with a pressure sensor 487. The pressure sensor 487 detects the pressure value of this air pipe 481, thereby detecting the suction force of the holding surface 22.

The air pipe 481 is also connected to a water pipe 491. The water pipe 491 is a pipe that connects the holding surface 22 of the chuck table 20 to the water supply source 49.

One end of the water pipe 491 is connected to the suction flow path 470 via the air pipe 481 and the suction pipe 471. The other end of the water pipe 491 is connected to the water supply source 49. The water supply source 49 includes a pump or the like and is used to supply water to the holding surface 22 of the chuck table 20.

Furthermore, a water supply on-off valve 495 and a water adjustment unit 493 are disposed in the water piping 491, in this order from the water supply source 49 toward the suction flow path 470. The water supply on-off valve 495 switches the communication state between the water piping 491 and the water supply source 49. The water adjustment unit 493 is, for example, a proportional control valve, and is used to change the internal orifice diameter to adjust the flow rate of water sent from the water supply source 49 to the holding surface 22 when the water supply on-off valve 495 is open.
The water adjusting unit 493 may be a needle valve or a gate valve that manually adjusts the orifice diameter.

Next, the configurations of the loading mechanism 170 and the unloading mechanism 172 will be described. Note that in this embodiment, the loading mechanism 170 and the unloading mechanism 172 have the same configuration. Therefore, the following description will focus on the configuration of the unloading mechanism 172.

As shown in Figure 2, the discharge mechanism 172 includes a disk-shaped pad 80 and an arm 81 that suspends the pad 80 so that it can move up and down freely. One end of the arm 81 is connected to the upper end of a rotating column 82 that extends in the Z-axis direction from the first device base 10 (see Figure 1). The rotating column 82 is connected to a motor 94 that rotates the rotating column 82 together with the arm 81, and to a vertical movement mechanism 95 that moves the rotating column 82 together with the arm 81 in the vertical direction.

A disk member 84 is connected to the other end of the arm 81 via a support 83. Multiple (e.g., three) through-holes 85 are formed through the disk member 84 at equal intervals around its circumference. Bolts 86 connected to the pad 80 are inserted into the through-holes 85.

The bolt 86 has a shaft portion 87 having a diameter slightly smaller than that of the through-hole 85 and a head portion 88 formed at the upper end of the shaft portion 87 .
The shaft portion 87 is loosely fitted through the through-hole 85. The lower end of the shaft portion 87 is connected to the upper surface of the frame body 91 of the pad 80. The head portion 88 has a diameter larger than the through-hole 85, and limits the downward range of the bolt 86.
The bolt 86 also has a spring 860 as a shock absorbing member around the shaft 87. The upper end of the spring 860 contacts the lower surface of the disk member 84, while the lower end of the spring 860 contacts the upper surface of the frame 91 of the pad 80. The spring 860 biases the disk member 84 and the pad 80 in directions away from each other.

The arm 81 is able to suspend the pad 80 while absorbing impacts applied to the pad 80 via the disc member 84 and bolt 86 configured in this way.

The disc-shaped pad 80 has an area slightly larger than that of the wafer 100, for example, and includes a pad holding portion 90 made of a porous material and a frame 91 that supports the pad holding portion 90. The underside of the pad holding portion 90 forms a pad holding surface 92 that suction-holds the backside 102, which is the upper surface of the wafer 100.

The discharge mechanism 172 also includes a suction path 89. The suction path 89 extends through the arm 81, the support 83, the disc member 84, and the frame 91 of the pad 80, and its lower end is connected to the upper surface of the pad holding portion 90. The upper end of the suction path 89 is connected to a suction source 99.

Therefore, in the unloading mechanism 172, when the pad holding surface 92 is in contact with the wafer 100 held on the holding surface 22 of the chuck table 20, the suction force of the suction source 99 is transmitted to the pad holding surface 92 by connecting the suction source 99 to the suction path 89, allowing the pad holding surface 92 to hold the wafer 100 by suction.

The motor 94 and vertical movement mechanism 95 rotate and raise and lower the rotating column 82 and arm 81, thereby rotating and raising and lowering the pad 80 holding the wafer 100, and removing the wafer 100 from the chuck table 20.

As shown in FIG. 1, the grinding device 1 also includes a control unit 7 for controlling the grinding device 1. The control unit 7 includes a CPU that performs calculations according to a control program, and storage media such as memory. The control unit 7 executes various processes and provides overall control of each component of the grinding device 1.

For example, the control unit 7 controls the above-mentioned components of the grinding device 1 to perform the grinding process on the wafer 100.

In addition, in order to prevent a decrease in the suction force of the holding surface 22, which is the surface of the porous member 21 on the chuck table 20, the control unit 7 periodically performs self-grinding to grind the holding surface 22 using the grinding wheel 77 of the grinding mechanism 70, thereby removing grinding debris from the outer periphery of the holding surface 22.
When grinding the holding surface 22, a fluid may or may not be ejected from the holding surface 22.

In this self-grinding, grinding debris, including chips generated by grinding the porous member 21 due to grinding of the holding surface 22, grinding debris generated when grinding the wafer 100 remaining on the outer periphery of the holding surface 22, and abrasive grains that have fallen off the grinding wheel 77 that grinds the holding surface 22, may enter the interior of the porous member 21. Therefore, the control unit 7 performs a cleaning process to remove grinding debris from the porous member 21 and the holding surface 22.
The cleaning process in this embodiment will be described below.

[First holding step]
In the cleaning process, the control unit 7 first causes the robot 155 to take out the unprocessed wafer 100 from the first cassette 161, place it on the temporary placement table 154 of the temporary placement mechanism 152, and align the wafer 100 at a predetermined position.

Furthermore, the control unit 7 controls the carry-in mechanism 170 to hold the wafer 100 on the temporary placement mechanism 152. That is, the control unit 7 rotates and raises and lowers the pad 80 using the motor 94 and vertical movement mechanism 95 of the carry-in mechanism 170 shown in FIG. 2, thereby bringing the pad holding surface 92 into contact with the wafer 100 on the temporary placement mechanism 152. In this state, the suction source 99 is connected to the suction path 89, causing the carry-in mechanism 170 to suction-hold the wafer 100 with the pad holding surface 92 of the pad 80.

Then, the control unit 7 rotates and raises and lowers the pad 80 of the loading mechanism 170 to place the wafer 100 on the holding surface 22 of the chuck table 20 located near the temporary placement mechanism 152, and retracts the pad 80 from the chuck table 20. As a result, the holding surface 22 becomes covered with the wafer 100, as shown in FIG. 2.

Then, the control unit 7 opens the suction on-off valve 475 shown in FIG. 2 and adjusts the orifice diameter of the suction flow rate adjustment unit 473 to connect the porous member 21 of the chuck table 20 to the suction source 47. This causes the holding surface 22 of the chuck table 20 to hold the wafer 100 by suction. Note that the orifice diameter of the suction flow rate adjustment unit 473 may be fully open.

[Second holding step]
Next, the control unit 7 causes the carry-out mechanism 172 to hold the wafer 100 that is suction-held by the holding surface 22. That is, the control unit 7 causes the motor 94 and the vertical movement mechanism 95 of the carry-out mechanism 172 to rotate and raise and lower the pad 80, thereby bringing the pad holding surface 92 into contact with the wafer 100 that is held on the holding surface 22 of the chuck table 20. In this state, the suction source 99 is connected to the suction path 89, so that the carry-out mechanism 172 suction-holds the wafer 100 with the pad holding surface 92 of the pad 80.

As a result, the wafer 100 is held by the carry-out mechanism 172 while covering the holding surface 22 of the chuck table 20, as shown in FIG. 2. The control unit 7 then closes the suction on-off valve 475 to stop suction holding of the wafer 100 by the holding surface 22 of the chuck table 20.

[Fluid ejection process]
Next, the control unit 7 ejects two fluids, which are a mixed fluid of water and air, from the holding surface 22 that is covered with the wafer 100. As a result, the two fluids ejected from the holding surface 22 flow outward in the diameter direction of the holding surface 22 between the holding surface 22 and the wafer 100, and remove grinding debris from the porous member 21 of the chuck table 20 and the holding surface 22.

That is, the control unit 7 opens the air supply on-off valve 485 and the water supply on-off valve 495, and adjusts the orifice diameters of the air adjustment unit 483 and the water adjustment unit 493 to connect the porous member 21 of the chuck table 20 to the air supply source 48 and the water supply source 49. In this way, the control unit 7 supplies predetermined amounts of the two fluids, air and water, to the porous member 21, as shown by arrows 501 in FIG.
The orifice diameter of the air adjusting portion 483 and the orifice diameter of the water adjusting portion 493 may be fully opened.

The two-fluid supplied to the porous member 21 flows from bottom to top within the porous member 21 and is ejected to the outside from the holding surface 22 together with the grinding debris within the porous member 21. As a result, as shown in Figure 3, the wafer 100, which is held by the carry-out mechanism 172 while covering the holding surface 22, is lifted up from the holding surface 22 together with the pad 80 by the two-fluid 200 against the biasing force of the spring 860, as shown by arrow 503. Then, the two-fluid 200 containing the grinding debris flows out radially outward from the holding surface 22 through the gap between the holding surface 22 and the wafer 100.
At this time, as shown in FIG. 3, the spring 860 contracts as the pad 80 rises, causing the head 88 of the bolt 86 to rise above the upper surface of the disk member 84 .

After a predetermined time has elapsed since the start of the ejection of the two fluids 200, the control unit 7 closes the air supply on-off valve 485 and the water supply on-off valve 495 to stop the ejection of the two fluids 200. The control unit 7 then rotates and raises and lowers the pad 80 of the carry-out mechanism 172 that is holding the wafer 100, thereby separating the wafer 100 from the holding surface 22.

As described above, in this embodiment, by flowing the two-fluid 200 from below the porous member 21 toward the holding surface 22 while the holding surface 22 is covered by the wafer 100, grinding debris that has entered the porous member 21 from the holding surface 22 can be discharged from the porous member 21 and the holding surface 22. Therefore, when the wafer 100 is ground by the grinding mechanism 70, grinding debris can be prevented from becoming interposed between the holding surface 22 and the wafer 100, making it possible to grind the wafer 100 to a uniform thickness.

Furthermore, in this embodiment, the wafer 100, which is the workpiece, and the existing discharge mechanism 172 are used to discharge grinding debris from the porous member 21. Therefore, the amount of additional configuration required to discharge grinding debris from the porous member 21 and the holding surface 22 can be reduced, making it possible to discharge grinding debris while avoiding an increase in the size of the grinding device 1.

In the fluid ejection process, if the two-fluid 200 is supplied to the porous member 21 when the holding surface 22 is not covered by the wafer 100, the two-fluid 200 passes only through the parts of the porous member 21 through which it is easy to pass, and is ejected from the holding surface 22. This makes it difficult to eject grinding debris from the entire area of the porous member 21.

In this regard, in this embodiment, the two-fluid 200 is supplied to the porous member 21 while the holding surface 22 is covered by the wafer 100 held by the discharge mechanism 172. This allows the two-fluid 200 to be ejected from the holding surface 22 while pressure is applied to the holding surface 22, so the two-fluid 200 can be ejected from the entire surface of the holding surface 22. This makes it possible to discharge grinding debris from almost the entire area within the porous member 21.

After ejecting the two-fluid 200 from the holding surface 22, the control unit 7 may clean the surface 101, which is the underside of the wafer 100 that has been separated from the holding surface 22, using the underside cleaning mechanism 180 shown in FIG. 1, cover the holding surface 22 with the wafer 100 again, and eject the two-fluid 200 from the holding surface 22 to remove grinding debris from the porous member 21 and the holding surface 22.

In this case, the control unit 7 performs the following underside cleaning process after the fluid ejection process.

[Bottom surface cleaning process]
The control unit 7 rotates and raises and lowers the pad 80 of the unloading mechanism 172 holding the wafer 100, thereby separating the wafer 100 from the holding surface 22 and placing it directly above the lower surface cleaning mechanism 180, as shown in Figure 4.

The underside cleaning mechanism 180 includes a sponge roller 181, a hollow shaft 182 inserted into the sponge roller 181 to hold the sponge roller 181, and a base member 183 that rotatably supports the shaft 182. The shaft 182 is connected to a water source 185 via a coupling 184, allowing water from the water source 185 to be supplied to the sponge roller 181 through holes in the surface of the shaft 182.

Then, as shown in FIG. 4, the control unit 7 adjusts the position of the pad 80 of the carry-out mechanism 172 holding the wafer 100 so that the surface 101 of the wafer 100 contacts the sponge roller 181 of the lower surface cleaning mechanism 180. Furthermore, while supplying water to the sponge roller 181 of the lower surface cleaning mechanism 180, the control unit 7 causes the pad 80 holding the wafer 100 to pivot horizontally relative to the lower surface cleaning mechanism 180, as shown by arrow 505 in FIG. 4. As a result, the sponge roller 181 containing water comes into contact with the surface 101 of the wafer 100 while rotating, cleaning the surface 101.

After the entire surface 101 of the wafer 100 has been cleaned, the control unit 7 ends the bottom surface cleaning process and rotates and raises and lowers the pad 80 of the discharge mechanism 172 so that the wafer 100 covers the holding surface 22 of the chuck table 20. The control unit 7 then performs the fluid ejection process described above again to remove grinding debris from the porous member 21 and holding surface 22.

With this configuration, grinding debris can be repeatedly removed from the porous member 21 and the holding surface 22 while cleaning the surface 101, which is the underside of the wafer 100. Therefore, grinding debris can be effectively removed from the porous member 21 and the holding surface 22.

Furthermore, in the above-described embodiment, as shown in FIG. 2, the area of the pad 80 in the unloading mechanism 172 is slightly larger than the area of the wafer 100. Alternatively, as shown in FIG. 5, the pad 80 may have an area smaller than the area of the wafer 100.

In this configuration, the pad 80 does not hold the outer peripheral portion of the wafer 100. Therefore, when the two-fluid 200 is ejected from the holding surface 22 of the chuck table 20 during the fluid ejection process, a gap is likely to form between the holding surface 22 and the outer peripheral portion of the wafer 100. Therefore, the two-fluid 200 containing grinding debris is likely to be discharged radially outward from the gap between the holding surface 22 and the wafer 100, making it possible to effectively remove grinding debris from the porous member 21 and the holding surface 22.

In the above-described embodiment, a wafer 100 is used as the plate-like object covering the holding surface 22 of the chuck table 20 during the fluid ejection process. In this regard, a dummy wafer or a plate-like object may be used as the plate-like object covering the holding surface 22. The dummy wafer is, for example, a wafer that is not the target of grinding by the grinding device 1. The plate-like object is, for example, a plate used for cleaning the porous member 21. In this case, the dummy wafer or plate-like object is stored in the first cassette 161 in advance, and is removed by the robot 155 during the first holding process and held by suction on the holding surface 22 of the chuck table 20.

In addition, in the above-described embodiment, the control unit 7 performs the fluid ejection process with the holding surface 22 of the chuck table 20 covered by the wafer 100 held by the carry-out mechanism 172. Alternatively, the control unit 7 may perform the fluid ejection process with the holding surface 22 of the chuck table 20 covered by the wafer 100 held by the carry-in mechanism 170. In this case, in the second holding process, the carry-in mechanism 170 holds the wafer 100 that is suction-held on the holding surface 22. In this case, the lower surface cleaning mechanism 180 may be disposed near the carry-in mechanism 170.

1: grinding device, 6: turntable, 7: control unit, 10: first device base,
11: second device base, 15: column, 20: chuck table,
21: Porous member, 22: Holding surface, 23: Frame, 30: Rotation mechanism, 31: Motor,
32: driving pulley, 33: endless belt, 34: driven pulley, 35: rotating shaft,
40: fluid distribution mechanism, 47: suction source, 48: air supply source, 49: water supply source,
60: Grinding feed mechanism, 61: Z-axis guide rail, 62: Z-axis ball screw,
63: Z-axis moving table, 64: Z-axis motor, 66: holder,
70: grinding mechanism, 71: spindle housing, 72: spindle,
73: spindle motor, 74: wheel mount, 75: grinding wheel,
76: Wheel base, 77: Grinding wheel,
80: Pad, 81: Arm, 82: Rotating column portion, 83: Support column, 84: Disc member,
85: through hole, 86: bolt, 87: shaft portion, 88: head portion, 89: suction path,
90: Pad holding portion, 91: Frame body, 92: Pad holding surface, 94: Motor,
95: vertical movement mechanism, 99: suction source, 100: wafer, 101: front surface, 102: back surface,
152: temporary placement mechanism, 153: alignment member, 154: temporary placement table,
155: Robot,
156: spinner cleaning mechanism, 157: spinner table, 158: nozzle,
160: first cassette stage, 161: first cassette,
162: second cassette stage, 163: second cassette,
170: Carrying-in mechanism, 172: Carrying-out mechanism,
180: bottom surface cleaning mechanism, 181: sponge roller, 182: shaft,
183: base member, 184: joint, 185: water source, 200: two-fluid, 403: suction groove,
460: rotary joint, 470: suction flow path, 471: suction piping,
473: suction flow rate adjusting unit, 475: suction opening/closing valve, 481: air piping,
483: air adjustment unit, 485: air supply opening/closing valve, 487: pressure sensor,
491: Water piping, 493: Water adjusting section, 495: Water supply opening/closing valve, 860: Spring

Claims (1)

A grinding device comprising: a chuck table that suction-holds a plate-like object with a holding surface of a porous member; a grinding mechanism that grinds the plate-like object suction-held by the holding surface with a grinding wheel; a carry-in mechanism that holds the plate-like object and carries it onto the holding surface; a carry-out mechanism that holds the plate-like object and carries it out of the holding surface; and a control unit;
a bottom surface cleaning mechanism for cleaning the bottom surface of the plate-like object held by the carrying-out mechanism or the carrying-in mechanism;
The control unit
A plate-like object is suction-held on the holding surface;
holding the plate-like object held by the holding surface by suction using the carrying-out mechanism or the carrying-in mechanism;
A two-fluid mixture of water and air is ejected from the holding surface covered with the plate-like object;
After the two fluids are ejected from the holding surface, the lower surface of the plate-like object separated from the holding surface is cleaned by the lower surface cleaning mechanism, the holding surface is covered with the plate-like object again, and the two fluids are ejected from the holding surface.
Control the
The two fluids ejected from the holding surface flow outward in the diameter direction of the holding surface between the holding surface and the plate-like object, removing grinding debris from the porous member and the holding surface.
Grinding equipment.