JPH01205950A - Cleaning method for porous chuck table and device therefor - Google Patents

Abstract

PURPOSE:To effectively remove chips entrapped with a porous member by applying the constitution wherein a pressurized fluid is supplied for blowing out the chips and a table rubbing member is actuated to remove the chips. CONSTITUTION:A pump 18 is driven to supply a pressurized fluid to the bottom side of the porous member 20 of a porous chuck table 3. The fluid is thereby blown to the surface side of the porous member 20 via the infinite number of holes therein and machined chips entrapped with the holes of the porous member 20 are made to flow out together with the fluid. Even if chips projected from the holes are existing, an oil stone device 25 is driven and an oil stone 26 is made to press and rub the surface of the porous chuck table 3, thereby enabling the removal of the aforesaid chips. As aforementioned, the cleaning of the porous chuck table 3 can be attained by cooperation between the blow effect of the pressurized fluid and the removal function of the oil stone 26.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cleaning method and a cleaning device for a porous chuck table that is mounted on a grinding machine and holds a workpiece by suction.

[Conventional technology]

A grinding machine that grinds a workpiece such as a wafer is equipped with a chuck table, and the workpiece is held by suction on the chuck table to grind the workpiece.

FIG. 7 shows an example of a grinding machine equipped with a chuck table. In the figure, a turntable 2 is rotatably disposed on a bed base 1, and a pair of chuck tables 3a, 3b are rotatably disposed on the surface of the turntable 2. In the figure, reference numeral 4 denotes a head mounted on a head base l so as to be movable up and down.A rotatable spindle 5 is vertically disposed on this head 4, and a grindstone 6 is fixed to the lower end of the spindle 5. There is. Reference numeral 7 indicates a wafer as a workpiece that is held by suction on the chuck tables 3a and 3b, 8 is a brush that reciprocates and rotates in the direction of the arrow, and IO adsorbs the wafer 7 with a suction cup 11; This is a transfer arm that transports the cough wafer 7 along the rail 12.

When grinding the wafer 7 using this type of grinding machine, the following procedure is followed.

First, the wafer 7 carried in by a loading means (not shown) is sucked by the suction cup 11, and is transported to a predetermined position on the chuck table 3a by the transfer arm 10 and placed there. At this fixed position, the wafer 7 is held by suction on the chuck table 3a.

Next, the turntable 2 is rotated 180 degrees, and the wafer 7 is
is moved to the grindstone 6 side, and the grindstone 6 is rotated to perform grinding. During this grinding, the wafer 7 to be processed next is similarly held by suction on the chuck table 3b. When the grinding of the wafer 7 is completed, the turntable 2 is rotated to 180° again.
While the wafer 7 on the chuck table 3b is rotated and ground, the wafer 7 after grinding is transferred from the chuck table 3a to an unloading means (not shown) by the transfer arm 10. After the wafer 7 is removed from the chuck table 3a, a cleaning liquid such as water is applied to the surface of the chuck table 3a by a cleaning liquid supply means (not shown), and the brush 8 is rotated to clean the surface of the chuck table 3a. It will be done. In this way, by repeating the procedure from placing the wafer 7 on the chuck table to removing the wafer 7 and cleaning the surface of the chuck table, the wafer 7 is ground and the chuck table is cleaned one after another. It is.

By the way, as shown in FIG. 8, the chuck tables 3a and 3b used in this type of grinding machine used to be
A metal base 13 with a plurality of vacuum suction holes 14 was used. However, when the wafer 7 is sucked and held using the vacuum suction holes 14 using such chuck tables 3a and 3b, a local suction force acts on the vacuum suction holes 14. A problem occurred in that the shape of the hole was transferred onto the surface of the wafer 7. In recent years, in order to avoid such inconvenience,
A porous chuck table is used in which a porous member having numerous holes formed therein is arranged on the surface side of the chuck table. If this porous chuck table is used, the wafer 7 is sucked using the countless holes in the porous member, so the suction force acts uniformly on the surface of the wafer 7, and the hole shape is transferred to the surface of the wafer 7. This will eliminate the above-mentioned inconvenience.

[Problem to be solved by the invention]

However, since the porous chuck table has countless minute holes on its surface, it is easy for grinding chips to get into these holes. It is difficult to completely remove it even if you rub the surface. As a result, the porous chuck table (specifically, the porous member) becomes clogged, weakening the vacuum suction force, and holding the wafer 7 incompletely, or some of the grinding debris that has entered the hole of the porous member may be removed from the chuck. A new problem has come to light: the protrusion protrudes from the surface of the table, hits the surface of the wafer 7, and cracks occur in the wafer 7 from the hit area.

The present invention has been made to solve the above problems, and its purpose is to provide a porous chuck table (porous member) that can effectively remove the grinding waste even if the grinding waste enters the hole of the porous chuck table (porous member). An object of the present invention is to provide a chuck table cleaning method and cleaning device.

[Means to solve the problem]

In order to achieve the above object, the present invention is configured as follows. That is, the cleaning method of the present invention is a method for cleaning a porous chuck table that sucks and holds a workpiece to be ground by a grindstone, in which the workpiece after grinding is removed from the surface of the porous chuck table. Pressurized fluid is supplied from the bottom side of the porous member toward the surface side to blow out the grinding debris that has entered the holes of the porous member to the surface side,
The apparatus of the present invention is characterized in that the table rubbing member is pressed against the surface of the porous chuck table to remove grinding debris protruding from the surface of the porous chuck table from the holes of the porous member. A pressurized fluid supply means for supplying pressurized fluid to the bottom side of the porous member on the table, a table rubbing member disposed on the surface side of the porous chuck table, and a pressurizing force of the table rubbing member to the surface of the porous chuck table. The structure is characterized by having a sliding member driving mechanism that performs driving and pressing release driving.

[Effect]

In the present invention configured as described above, by driving the pressurized fluid supply means to supply the pressurized fluid to the bottom side of the porous member on the porous chuck table, the pressurized fluid is supplied to the numerous points inside the porous member. It is ejected to the surface through the pores (porous pores). With this outpouring,
Grinding debris that has entered the pores of the porous member is discharged from the pores and flows out together with the pressurized fluid.

In addition, even if the grinding debris protruding from the porous holes to the surface remains, the protruding portion of the grinding debris can be removed by driving the sliding member drive mechanism to press the sliding member against the surface of the porous chuck table. will be removed by doing so. In this manner, in the present invention, cleaning of the porous chuck table surface is achieved by the cooperation of the jetting action of the pressurized fluid and the removal action by the rubbing member.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 shows an embodiment of a cleaning device according to the present invention. In the figure, a porous chuck table 3 is rotatably mounted on the turntable 2 of the grinding machine shown in FIG. 7. This porous chuck table 3 is made by integrally connecting a passage forming base 15 and a porous accommodation base 16, and the passage forming base 15 has a vacuum suction passage and a pressurized fluid supply passage 17 inside. is formed. The vacuum suction passage and pressurized fluid supply passage 17 may be formed independently as separate passages, or one passage may be formed and used for vacuum suction and pressurized fluid supply. It may be used for both purposes as appropriate. The pressurized fluid supply passage 17 is branched into a plurality of passages at the inlet side 17a, and the outlet side of each branch passage faces the bottom side of the porous accommodation base 16. Further, an inlet side 17a of the passage 17 communicates with a pump 18 for supplying pressurized fluid.

The porous accommodation base 16 has a counterbore-shaped recess formed in the center of the front surface, and the porous member 20 is placed in this recess.
is accommodated. The porous member 20 is made of a material such as vitrified material, and has numerous pores (porous pores) formed on the surface and inside thereof like a sponge. A plurality of through holes 21 communicating with the pressurized fluid supply passage 17 (specifically, each branch passage thereof) are formed in the bottom wall of the base 16, and the pressurized fluid supplied from the pump 18 is passed through the passage 17 and He is trying to guide it to the bottom side of the porous member 20 through the through hole 21. These through holes 2
1, the pressurized fluid supply passage 17, the pump 18, and the control device 22 that controls the operation of the pump 18 constitute pressurized fluid supply means. The pressurized fluid may be a gas such as air, a liquid such as water, or a mixture of these gases and liquids, and the type of pressurized fluid may be selected according to the specifications. Set.

On the other hand, near the surface side of the porous chuck table 3, a spray nozzle 23 for spraying a cleaning liquid such as water is arranged with its spray surface facing the surface of the chuck table 30. The flow path of this injection nozzle 23 communicates with the discharge port of a pump 24, and by driving the pump 24, cleaning water is sprayed onto the surface of the porous chuck table 3. The operation of the pump 24 is controlled by the control device 22, and these, the injection nozzle 23 and the pump 24
and the control device 22 constitute a cleaning liquid supply means.

Further, an oil stone device 25 as a table rubbing device is arranged near the surface side of the porous chuck table 3. This oil stone device 25 includes an oil stone 26 as a table rubbing member, a frame body 27 that accommodates this oil stone 26, and a holding frame 28 that loosely fits this frame body 27. The base end side of the frame body 27 is rotatably supported on the holding frame 28 by a pin 30. A spring 31 is interposed between the distal end side of the frame body 27 and the holding frame 28, which always urges the oil stone 26 forward (in the direction of the porous chuck table).

This oil stone device 25 is held by an oil stone drive mechanism 32 serving as a sliding member drive mechanism that presses and drives the oil stone 26 against the surface of the porous chuck table 3.

Although various other configurations are possible for the oil stone drive mechanism 32, in this embodiment, the drive mechanism 32 is configured using a cylinder device 33.

That is, in FIG. 1, the oil stone drive mechanism 32 is
Cylinder device 33, operating rod 34, and holding arm 3
5, a sleeve portion 36, and a control device 22 that controls the operation of the cylinder device 33.

The cylinder device 33 is fixed to the bed base 1 of the grinding machine via an arm 37 and the like, and a cylinder rod 38
and the tip of the actuating rod 34 are connected by a coupling 40. Further, one end of a transmission arm 44 is connected to the base end of the actuation rod 34 by a pin, and the other end of the transmission arm 44 and the base end of a holding arm 350 are fixed to the sleeve portion 36. This cylindrical shaft portion 36 is fitted onto a shaft 41 and is rotatable about the shaft 41 as a fulcrum. A holding frame 28 of the oil stone device 25 is fixed to the tip of the holding arm 35.

The cleaning device of this embodiment is constructed as described above, and a method of cleaning a porous chuck table using the same device will be described below along with the operation of the device.

First, when cleaning the surface of the porous chuck table 3, the wafer 7 that has been ground is removed from the porous chuck table 3 by the transfer arm 10, as described in FIG. After removing the wafer 7, the pump 24 is activated while the porous chuck table 3 is rotated, and the cleaning liquid is sprayed from the spray nozzle 23 toward the surface of the table 3.

On the other hand, the cylinder device 33 is driven to raise the cylinder rod 38 in the state shown in FIG. This rod 38
As a result of this rise, the sleeve portion 36 rotates counterclockwise about the shaft 41 as a fulcrum. Therefore, the holding arm 35 whose base end is fixed to the cylindrical shaft portion 36 also rotates counterclockwise, and the oil stone 26 comes into contact with the surface of the porous chuck table 3.

In this case, since the oil stone 26 receives the biasing force of the spring 31 and the rotational force in the counterclockwise direction about the pin 30, the distal end 26a protrudes more inclined forward than the proximal end 26b. ing. Therefore, the oil stone 26 first contacts the surface of the porous chuck table 3 with its distal end 26a, and then gradually contacts the proximal end 26b as the cylinder rod 38 rises.
Finally, as shown in FIG. 2, the ground surface of the oil stone 26 comes into uniform contact with the surface of the table 3.

If the porous chuck table 3 is rotated in this contact state, as shown in FIG. The shavings are flushed out by the cleaning fluid.

When cleaning the porous chuck table 3, in this embodiment, the pump 18 is further activated, and pressurized fluid is supplied to the lower surface (bottom surface) side of the porous member 20 through the pressurized fluid supply passage 17 and the through hole 21. be done. This pressurized fluid passes through the porous holes 42 inside the porous member 20 and is ejected to the surface side. The fine grinding debris that has entered the porous hole 42 by this jet of pressurized fluid is jetted out to the surface side by the jet of pressurized fluid, and the jetted grinding debris is flowed out to the outside by the cleaning liquid.

In this manner, in this embodiment, the jetting action of the pressurized fluid, the scraping action of the grinding debris by the oil stone 26, and the outflow action of the cleaning fluid cooperate to provide an effective removal action of the grinding debris. In addition, the squirting of pressurized fluid is
It may be carried out before grinding the oil stone 26, it may be carried out simultaneously with the grinding of the oil stone 26, or it may be carried out continuously before and after grinding the oil stone 26. When the cleaning of the porous chuck table 3 is completed, the cylinder device 33 is advanced and the cylinder rod 38 is moved forward.
moves downward. Therefore, the holding arm 35 rotates clockwise and the pressing operation of the oil stone 26 is released. Then, the oil stone 26 is returned to its original position (
It returns to the state shown in Figure 1) and is ready for the next cleaning.

FIGS. 4 and 5 show other configuration examples of the oil stone drive mechanism. In the description of the configuration examples shown in FIGS. 4 and 5, the same parts as those shown in FIG.

The devices shown in the fourth and fifth sections are configured so that the oil stone 26 can be rotated in the front and back direction by rotating the frame 27 with the bottle 30 as a fulcrum, similar to the device shown in FIG. However, a distinctive feature different from the device shown in FIG. 1 is that the oil stone 26 is configured to be able to rotate in the left-right direction and move in the front-back direction.

That is, a box-shaped cylinder 45 is provided on the lower surface of the holding arm 35.
is fixed, a piston 46 is slidably housed in the cylinder 45, and the shaft portion of the piston 46 passes through both front and rear end walls of the cylinder 450 in an airtight and slidable manner and protrudes to the outside. The protruding tip portion is pivotally supported by the holding frame 28. Therefore, the piston 46 is
8 functions as a rotating wheel for rotating in the left-right direction, and as the cylinder rod 38 rises, the holding arm 35 rotates counterclockwise, and the tip 26a of the oil stone 26 contacts the porous chuck table 3. At this time, the oil stone 26 rotates back and forth (more specifically, clockwise) about the pin 30 as a fulcrum), and further rotates from side to side (direction in the figure) using the piston 46 as a fulcrum while rotating on the surface of the porous chuck table 30. Let's get in touch. By applying the horizontal rotation of the oil stone 26 in this way, the bottom surface (grinding surface) of the oil stone 26 comes into contact with the surface of the porous chuck table 3 in a more familiar state, and the sliding effect of the table 3 can be done more effectively.

Further, since the oil stone 26 is fixed to the piston 46 via the frame body 27 and the holding frame 28, for example, if working fluid is supplied into the cylinder 45 from the working hole 47, the piston will be moved by the fluid pressure. 46 slides forward, and conversely, if working fluid is supplied into the cylinder 45 from the working hole 48 on the opposite side, the piston 46 slides backward. That is, by sequentially switching the flow path of the working fluid supplied into the cylinder 45, the piston 46 slides in the front-rear direction, and the oil stone 26 also moves in the front-rear direction in conjunction with the piston 46.

If the oil stone 26 is moved back and forth when it is rubbed against the porous chuck table 3, the rubbing action can be performed more effectively, and the cleaning effect of the table 3 can be greatly enhanced.

Note that the present invention is not limited to the above-mentioned embodiments, and can take various embodiments. For example, in this embodiment, the vertical movement of the operating rod 34 is converted into the rotational movement of the holding arm 35 to press the oil stone 26 against the porous chuck table 3, but unlike this, the vertical movement of the operating rod 34 directly The oil stone may be pressed against the surface of the table 3 via a spring or the like.

In addition, in FIG. 1, the porous member 20 is fitted over the entire recess space of the porous accommodation base 16, but for example, as shown in FIG. Partition ring 4 made of shaped ceramics, etc.
A plurality of partition rings 44 may be accommodated, and the porous member 20 may be accommodated in the space between the partition rings 44. This table has independent suction areas formed by the partition rings 44, and is configured so that the suction area can be arbitrarily switched by switching the suction passage corresponding to each suction area. The wafer can be reliably sucked and held.

Furthermore, although the brush 8 shown in FIG. 7 is omitted in this embodiment, this brush 8 is arranged on the surface side of the porous chuck table 3, and the oil stone 26 and this brush 8 are used together. The surface of the table 3 may also be cleaned.

Furthermore, in this embodiment, an oil stone is used as the table rubbing member, but the present invention is not limited to this. For example, a whetstone in which abrasive grains such as CBN are formed with a suitable bonding agent such as resin bond may be used. You can.

〔Effect of the invention〕

As explained above, the present invention uses pressurized fluid to blow out minute grinding chips that have entered the porous holes of the porous chuck table onto the surface, and scrapes off the grinding chips protruding from the porous holes with an oil stone. Since it is configured to remove the grinding debris spewed out on the surface and the shavings scraped off by the oil stone, the surface of the chuck table can be cleaned flat without any grinding debris protruding onto the surface of the porous chuck table. . Therefore, when the wafer is adsorbed after cleaning,
Grinding debris does not locally hit the wafer surface and cause the wafer to crank.

In addition, since minute grinding debris that enters the porous holes are ejected by the pressurized fluid to the surface side, the porous holes are not clogged, and a suitable suction force can be applied to the wafer when the wafer is attracted.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram of the operation of the same embodiment, FIG. Figure 4 is a perspective view showing another configuration example of the oil stone drive mechanism;
The figure is a sectional view of the oil stone device part shown in Figure 4, Figure 6 is a diagram of another aspect of the porous chuck table, and Figure 7 is a plan view showing an example of a grinding machine equipped with a brush cleaning device.
FIG. 8 is a sectional view showing the structure of a former chuck table. ■... Head base, 2... Turntable, 3...
・Porous chuck table, 3a, 3b... Chuck table, 4... Head, 5... Spindle, 6
... Grindstone, 7... Wafer, 8... Brush, lO
...Transfer arm, 11...Sucker, 12...
・Rail, 13... Metal base, 14... Vacuum suction hole, 15... Passage formation base, 16... Porous accommodation base, 17... Pressurized fluid supply passage, 17a. ...Inlet side, 18...Pump, 20...Porous member, 21
... Through hole, 22 ... Control device, 23 ... Injection nozzle, 24 ... Pump, 25 ... Oil stone device, 26 ... Oil stone, 27 ... Frame, 28
...Holding frame, 30...Pin, 31...Spring, 32
... Oil stone drive mechanism, 33 ... Cylinder device, 34 ... Operating rod, 35 ... Holding arm, 3
6... Cylinder shaft portion, 37... Arm, 38... Cylinder device door, 4o... Coupling, 41... Shaft, 4
2... Porous hole, 43... Grinding waste, 44...
Transmission arm, 45... cylinder, 46... piston, 47.48... operating hole. $22 Figure 3 5th calm 6th calm

Claims (2)

[Claims] (1) In a method for cleaning a porous chuck table that suction holds a workpiece to be ground by a grindstone, after the workpiece after grinding is removed from the surface of the porous chuck table, the bottom surface of the porous member on the porous chuck table is Pressurized fluid is supplied toward the surface side from the porous member to blow out the grinding chips that have entered the holes of the porous member toward the surface side. At the same time, the table rubbing member is pressed against the surface of the porous chuck table to rub it against the surface of the porous member. A method for cleaning a porous chuck table characterized by removing grinding debris protruding from the hole to the surface. (2) A pressurized fluid supply means for supplying pressurized fluid to the bottom side of the porous member in the porous chuck table, a table rubbing member arranged on the front side of the porous chuck table, and a porous chuck of the table rubbing member. 1. A cleaning device for a porous chuck table, comprising: a sliding member drive mechanism that presses the table surface and drives the table surface to release the pressure.