JP2003340718A - Grinding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suction table grinding machine for sufficiently removing chips generated when grinding a suction table, and as a result, improving the grinding accuracy of a semi-conductor wafer. <P>SOLUTION: This grinding machine 10 comprises a suction table 12 having a disk-shaped porous member 18, and a grinding unit 14 having a grinding wheel 20 to flatten the porous member 18. A feed port 20A is formed in a center part of the grinding wheel 20, and pure water is fed to the feed hole 20A. A block 34 having a suction hole 34A is provided around the grinding wheel 20, and a brush 38 is provided between the block 34 and the grinding wheel 20. Chips generated when grinding the porous member 18 by the grinding wheel 20 are swept outside by the brush 38, and sucked and removed from the suction hole 34A. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding machine, and more particularly to a grinding machine for grinding a porous member of a suction table that holds a semiconductor wafer in the final step of manufacturing the semiconductor wafer.

[0002]

2. Description of the Related Art In the final step of manufacturing a semiconductor wafer, the back surface of a semiconductor wafer having a large number of semiconductor devices on its front surface is ground to a desired thickness, and then sent to a dicing step to be divided into individual semiconductor chips. is doing.

The back surface grinding apparatus for semiconductor wafers is equipped with a suction table for holding the front surface of the semiconductor wafer by suction. The suction table is configured by fitting a disk-shaped porous member inside a cup-shaped frame.
The inside of the frame is connected to an air suction means. By sucking air by this suction means, a suction force is generated on the surface of the porous member, and the surface of the semiconductor wafer is suction-held. With this, a grinding stone can be pressed against the back surface of the semiconductor wafer while adsorbing and holding the front surface of the semiconductor wafer for grinding.

By the way, when the back surface of the semiconductor wafer is ground, if the surface of the suction table has irregularities, the accuracy of the grinding process may decrease. Therefore, in order to keep the grinding process of the back surface of the semiconductor wafer with high accuracy, it is necessary to make the suction table as flat as possible. Therefore, in the conventional grinding device, the surface of the suction table is ground and flattened every time a plurality of semiconductor wafers are ground. A grinding device for a suction table is described, for example, in Japanese Patent Application Laid-Open No. 9-155747. In this grinding apparatus, the porous member is flattened over the entire surface by working with a grinding wheel having an ear portion. This improves the accuracy of the grinding process of the semiconductor wafer using the suction table.

[0005]

However, the grinding device described in Japanese Patent Laid-Open No. 9-155747 cannot sufficiently remove the grinding dust generated when the porous member is ground, and the grinding dust is not generated on the porous member. There is a problem of remaining. Grinding dust is generally removed by applying running water such as pure water during the grinding process or by air blowing after the grinding process. However, the grinding dust that has entered the inside of the porous member cannot be sufficiently removed by running water or air blow,
Grinding dust may remain on the porous member. If the grinding dust remains on the porous member, the suction force for sucking the semiconductor wafer is reduced, so that the processing accuracy of the semiconductor wafer may be reduced even if the porous member is flattened. Therefore, in order to improve the processing accuracy of the semiconductor wafer, it is necessary not only to flatten the porous member but also to sufficiently remove the grinding dust attached to the porous member. Particularly, in the case of an extremely thin semiconductor wafer (for example, having a thickness of 200 μm or less) required in recent years, further improvement in processing accuracy is required, and therefore it is necessary to sufficiently remove grinding dust.

The present invention has been made in view of the above circumstances, and it is possible to sufficiently remove the grinding dust generated when the suction table is ground, and as a result, the accuracy of the grinding process of the semiconductor wafer is improved. An object of the present invention is to provide a grinding device for a suction table that can be used.

[0007]

In order to achieve the above-mentioned object, the present invention provides a grinding apparatus equipped with grinding means for grinding the adsorption surface of an adsorption table for adsorbing and holding a workpiece. A suction means arranged in a ring shape so as to surround the grinding means, and grinding dust generated by the grinding means provided between the suction means and the grinding means toward the suction means. Sweeping-out means for sweeping out, and the grinding dust is removed by sweeping out the grinding dust by the sweeping means and sucking by the suction means.

According to the present invention, since the grinding dust generated by the grinding process by the grinding means is swept out by the sweeping means and sucked by the suction means, the grinding dust can be surely removed, and the suction table It is possible to prevent grinding debris from remaining on the surface. Particularly, according to the present invention, since the sweeping means and the suction means are arranged around the grinding means, it is possible to completely remove the grinding dust generated from the grinding means side. Further, as described in claim 2, it is possible to perform the work of removing the grinding dust while performing the grinding process by the grinding means.

According to the third aspect of the present invention, since the sweeping means and the grinding means are separately provided so as to be movable back and forth with respect to the suction surface, only one of the grinding means and the sweeping means is selected. The suction surface can be brought into contact, or both the grinding means and the sweeping means can be brought into contact with the suction surface. That is, claim 3
In the invention described in (1), either one of the grinding process and the sweeping work can be selected and performed, or both the grinding process and the sweeping work can be performed simultaneously. Therefore, for example, after performing both the grinding process and the sweeping work at the same time, only performing the sweeping work,
It is also possible to surely remove the grinding dust.

According to the invention described in claim 4, since the fluid is supplied to the suction table and the fluid is passed to the suction means side of the suction surface, the grinding dust that has entered the suction table is sucked by the suction means. Is discharged to the side and sucked and removed by the suction means. Therefore, the grinding dust that has entered the suction table can be reliably removed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of a grinding apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an overall structural diagram showing a grinding device of the present embodiment.

As shown in FIG. 1, the grinding apparatus 10 includes a suction table 12 for holding a semiconductor wafer 11 by suction.
And the processing section 14 arranged opposite to the suction table 12.
It consists of and.

The suction table 12 is composed of a cup-shaped frame 16 and a disk-shaped porous member 18, and the porous member 18 is fitted in a recess on the upper surface of the frame 16. The porous member 18 is a porous member formed by solidifying a granular material such as ceramics or SUS, and has sufficient strength to hold the semiconductor wafer 11 and sufficient air permeability to transmit suction force. There is.

The frame 16 is connected to a motor (not shown) and is configured to rotate about the central axis C1. A through hole 16A is formed in the center of the frame 16, and the through hole 16A is connected to the air suction device and the fluid supply device via a switching valve (not shown). When the switching valve is operated to connect the air suction device to the through hole 16A, the suction force is transmitted to the upper surface of the porous member 18 and the semiconductor wafer 11 is suctioned to the upper surface of the porous member 18. Further, when the fluid supply device is connected to the through hole 16A, the fluid is blown out from the upper surface of the porous member 18. The fluid may be any fluid that passes through the porous member 18, and for example, water, air, or both water and air are used. A circular groove 16C is formed at the center of the bottom surface 16B of the concave portion of the frame 16, and a circumferential groove 16D is formed at the peripheral portion. Circular groove 16
C and the circumferential groove 16D are communicated with each other by a plurality of connecting grooves 16E, 16E formed in the radial direction of the frame 16.
As a result, when air is sucked from the through hole 16A, the porous member 18 passes through the circular groove 16C and the circumferential groove 16D.
The suction force works almost evenly on the entire surface of. Similarly, through hole 16A
When the fluid is supplied to, the fluid is blown out substantially uniformly from the entire surface of the porous member 18.

On the other hand, the processing section 14 mainly comprises the grindstone 20,
It is composed of a base plate 22 and a frame 24.
The grindstone 20 is formed in a disk shape, is arranged to face the porous member 18, and is detachably attached to the base plate 22. The grinding stone 20 and the base plate 22 have holes for pure water supply (hereinafter,
20A and 22A (referred to as supply holes) are formed, and the supply holes 20A and 22A are connected to a pure water supply means (not shown).

The base plate 22 is arranged inside a cup-shaped frame 24 arranged downward, and the plate spring 2 is provided.
It is attached to the frame 24 via 6, 26, ....
The leaf springs 26, 26, ... Are disposed at four positions at 90 ° intervals around the central axis C2 of the base plate 22 (see FIG. 2), and the base plate 22 is attached to the inside (that is, the upper side) of the frame 24. I am energetic.

An airbag 28 is provided between the frame 24 and the base plate 22. The airbag 28 is
It is connected to an air supply means (not shown), and the air bag 28 is expanded by supplying air from this air supply means. When the airbag 28 is inflated, the base plate 22 descends and the grindstone 20 is pressed against the porous member 18. At that time, the porous member 1 of the grindstone 20 is adjusted by adjusting the air pressure supplied to the airbag 28.
The pressing force on 8 is adjusted. When the air is discharged from the airbag 28, the plate spring 26 raises the base plate 22, and the grindstone 20 is separated from the porous member 18 and retracts. Since the base plate 22 is supported by the four leaf springs 26 arranged at equal intervals, the base plate 22 is moved up and down while maintaining the state parallel to the porous member 18.

A cylindrical support member 30 is attached to the upper surface of the frame 24, and the support member 30 is connected to a rotary shaft of a motor (not shown) via a rotary joint 32. Therefore, by driving the motor, the frame 24 is rotated about the central axis C2. Also,
The frame 24 is connected to a cylinder device (not shown), and is provided so as to be movable up and down.

A ring-shaped block 34 is attached to the outer peripheral portion of the frame 24. A taper 34C is formed at the lower end of the block 34 toward the inside. Further, inside the block 34, a hole for sucking air (hereinafter,
A suction hole) 34A is formed in the vertical direction. The upper end of the suction hole 34A is connected to a suction device (not shown) via the pipe 36, the internal flow path of the support member 30, the rotary joint 32, and the like. Further, the lower end of the suction hole 34A communicates with a suction port 34B (see FIG. 2) formed in the taper 34C. The suction port 34B is provided in the frame 24
A plurality of them are formed at equal angular intervals centered on the central axis C2. Therefore, when a suction device (not shown) connected to the suction hole 34A is driven, a substantially uniform suction force acts on the entire taper 34C.

A brush 38 is attached downward to the lower end of the frame 24. Brush 38 is block 34
Is arranged so as to protrude from the lower end of the. The brush 38 is brought into contact with the porous member 18 so that the frame 24, the frame 1
By rotating 6 the grinding dust adhering to the porous member 18 is swept out to the outside. The brush 38
It is preferable to have a shape that facilitates sweeping out grinding dust from the inside to the outside. For example, as shown in FIG.
If the frame 16 is formed in a curved shape in the rotation direction of the frame from the outside to the inside, the grinding dust can be efficiently swept from the grindstone 20 on the inside toward the suction port 34B on the outside. The brush 38 is selected to have sufficient flexibility so as not to damage the porous member 18.

Next, the operation of the grinding device 10 configured as described above will be described.

When grinding the porous member 18 of the suction table 12, first, the suction table 12 and the processing portion 14 are rotated. At that time, the suction table 12 and the processing unit 1
The rotation directions of 4 may be the same direction or opposite directions.

Next, the suction device (not shown) connected to the suction hole 34A of the block 34 is driven to perform suction work from the suction port 34B, and at the same time, the pure water supply connected to the supply hole 20A of the grindstone 20 is supplied. The means is driven to supply pure water from the supply hole 20A.

Next, the entire processing section 14 is lowered to the position shown in FIG.
As shown in (A), only the brush 38 is used for the porous member 18
Abut. Then, by inflating the airbag 28 and lowering the grindstone 20, the grindstone 20 is pressed against the porous member 18 as shown in FIG. 3 (B). As a result, the porous member 18 is ground. Grinding dust generated at that time is swept outward by the brush 38 and sucked through the suction port 34B at the lower end of the block 34. As a result, the grinding dust can be removed while performing the grinding work, so that it is possible to prevent the grinding precision from being lowered due to the influence of the grinding dust.

When the grinding process is completed, the air is exhausted from the air bag 28 to move the grindstone 20 upward. As a result, as shown in FIG. 3A, only the brush 38 is in contact with the porous member 18. At that time, since the pure water is supplied from the supply hole 20A of the grindstone 20 and is sucked from the suction port 34B of the block 34, the grinding dust on the porous member 18 is flowed by the pure water and is also brushed by the brush 38. It is swept out to the outside and sucked into the suction hole 34. As a result, the porous member 18 is cleaned.

While the above-described porous member 18 is being ground or cleaned, the frame 1 of the suction table 12 is
6 through hole 16A is connected to a fluid supply device (not shown),
A fluid may be supplied to the through hole 16A. The fluid supplied to the through hole 16A passes through the inside of the porous member 18 and is extruded onto the porous member 18. As a result, the grinding dust and contaminants that have entered the inside of the porous member 18 are pushed out together with the fluid onto the porous member 18, and are sucked and removed from the suction port 34A.

When the grinding process is on standby, rinse water may be supplied to the supply hole 20A of the grindstone 20 or the suction hole 34A of the block 34 to prevent the grindstone 20 from drying.

As described above, according to the grinding apparatus 10 of the present embodiment, the grinding dust generated during the grinding process is swept to the outside by the brush 38 and sucked from the suction port 34B. The debris can be removed sufficiently. Further, since only the brush 38 is pressed against the porous member 18 to perform the cleaning operation after the grinding process, it is possible to more reliably remove the grinding dust attached to the porous member 18. Further, since the fluid is passed through the porous member 18 and the grinding dust that has entered the inside of the porous member 18 is pushed out and sucked through the suction port 34B, the grinding dust that has entered the inside of the porous member 18 is reliably removed. can do.

Therefore, according to the grinding apparatus 10, since the grinding dust attached to the porous member 18 can be reliably removed, the suction force does not decrease when the semiconductor wafer 11 is sucked by the porous member 18. Hereinafter, a method of processing the semiconductor wafer 11 with the grinding device 10 will be described.

First, the grindstone 20 is removed from the base plate 22. Then, the grinding stone 20 for chamfering the porous member 18 is replaced with a grinding stone (not shown) for processing the semiconductor wafer 11 and mounted on the base plate 22. The above replacement work is not necessary when the surface of the porous member 18 and the semiconductor wafer 11 are ground using a common grindstone.

Next, a protective sheet (not shown) is attached to the surface of the semiconductor wafer 11, and the protective sheet is brought into contact with the porous member 18 so that the semiconductor wafer 11 is suction-held on the suction table 12. At that time, since the grinding dust on the suction table 12 is sufficiently removed, the semiconductor wafer 11 can be stably held with a sufficient suction force.

Next, the suction table 12 and the processing section 14 are rotated, pure water is supplied from the supply hole 20A of the grindstone 20, and suction is performed from the suction hole 34A of the block 34.
Then, the airbag 28 is inflated to lower the grindstone 20 and pressed against the back surface of the semiconductor wafer 11. As a result, the back surface of the semiconductor wafer 11 is ground. At that time, since the semiconductor wafer 11 is stably held by the suction table 12, the position of the semiconductor wafer 11 is not displaced during the grinding process, and the grinding process can be performed with high accuracy. In addition, the grinding dust generated during the grinding process is brush 3
Since it is swept out to the outside by 8 and is sucked into the suction hole 34A, grinding debris can be quickly removed, and the accuracy of grinding can be improved.

In the above embodiment, the grindstone 20 is used.
Although pure water is supplied from the supply hole 20A of the block 34 and suction is performed from the suction hole 34A of the block 34, conversely, pure water is supplied from the suction hole 34A and suction is performed from the supply hole 20A. Good. In that case, the frame 2 of the processing unit 14
4 may be rotated in a direction opposite to the rotation direction (see FIG. 2) of the above-described embodiment. As a result, the grinding dust on the outer side of the brush 38 is swept inward and sucked from the supply hole 20A.

Pure water may be supplied from the suction hole 34A during the grinding process, and pure water may be supplied from the supply hole 20A when cleaning with the brush 38 after the grinding process.

In the above-described embodiment, the whetstone 20 is moved up and down by inflating and contracting the airbag 28.
The raising / lowering means of the grindstone 20 is not limited to this, and the grindstone 20 may be raised / lowered by a cylinder or the like. Further, it is preferable that the grindstone 20 and the brush 38 can be raised and lowered separately. For example, the grindstone 20 and the brush 38 may be raised and lowered by different cylinders.

Although the disk-shaped grindstone 20 is used in the above-mentioned embodiment, a cup-shaped grindstone or the like may be used.

The present invention is particularly effective when the member forming the suction surface of the suction table 12 is the porous member 18, and has a great effect of suppressing the reduction of the suction force due to grinding dust, but the suction surface is The constituent members are not limited to this. For example, even when a stainless plate having a large number of small-diameter through holes formed therein is used as a member forming the suction surface of the suction table 12, the grinding device 10 described above is used.
By grinding the suction surface with, it is possible to prevent the grinding dust from remaining on the suction table 12.

The object to be adsorbed on the adsorbing table 12 is not limited to the semiconductor wafer 11 and may be any work that requires grinding.

[0039]

As described above, according to the grinding apparatus of the present invention, the grinding dust generated by grinding by the grinding means is swept out by the sweeping means and sucked by the suction means. Can be reliably removed from the porous member, and it is possible to prevent grinding dust from remaining on the porous member. In particular, according to the present invention, since the sweeping means and the suction means are arranged around the grinding means, it is possible to completely remove the grinding dust generated from the grinding means side, while performing the grinding process by the grinding means. It is possible to remove grinding dust.

[Brief description of drawings]

FIG. 1 is an overall structural diagram showing a grinding device of the present embodiment.

FIG. 2 is a bottom view of the processing part shown in FIG.

FIG. 3 is a diagram showing an operation of a grinding device.

[Explanation of symbols]

10 ... Grinding device, 12 ... Suction table, 14 ... Processing part,
16 ... Frame, 16A ... Through hole, 18 ... Porous member, 20 ... Whetstone, 20A ... Supply hole, 22 ... Base plate, 22A ... Supply hole, 24 ... Frame, 26 ... Leaf spring,
28 ... Airbag, 30 ... Supporting member, 32 ... Rotary joint, 34 ... Block, 34A ... Suction hole, 34B
… Suction port, 36… Piping, 38… Brush

Claims (4)

[Claims] 1. A grinding apparatus having a grinding means for grinding the suction surface of a suction table for sucking and holding a work, the suction means being arranged outside the grinding means in a ring shape so as to surround the grinding means. And a sweeping means which is provided between the suction means and the grinding means and sweeps out the grinding dust generated by the grinding process by the grinding means toward the suction means. A grinding apparatus, characterized in that the grinding dust is removed by sweeping with a discharging means and sucking with the suction means. 2. The grinding apparatus according to claim 1, wherein the grinding scraps are removed by the suction means and the sweeping means while the grinding means is performing the grinding process. 3. The sweeping means and the grinding means are separately provided,
3. The grinding device according to claim 1, further comprising an advancing / retreating means for advancing / retreating with respect to the suction surface. 4. A fluid supply means for supplying a fluid to the suction table and passing the fluid to the suction means side of the suction surface, according to any one of claims 1 to 3. The described grinding device.