JP2002210652A - Polishing jig and polishing device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To replace an O-ring without inserting the upper body or an arm into the under space of a lifted pressurizing plate or working upwardly from the downside, and thus to easily and safely exchange the O-ring. SOLUTION: This polishing jig 28 comprises a disk part 281, a cylindrical wall plate part 282 disposed around the disk part 281, and a plurality of annular grooves 20 formed concentrically to the disk part in the bottom parts of a recessed part 28a and a recessed part 28b formed with the disk part 281 and the cylindrical wall plate part 282. The polishing jig 28 in which O-rings 21 are selectively mounted to the annular grooves 20 is engaged under the pressurizing plate 8. A splash preventing skirt 41 is provided for preventing intrusion of polishing liquid, and can be turned up during working.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus and, more particularly, to a polishing jig suitable for use in a planar polishing apparatus for semiconductor wafers.

[0002]

2. Description of the Related Art Along with a demand for higher integration of semiconductor devices and minimization of a pattern size, higher precision is required for flatness of a semiconductor wafer surface. For this reason, in the polishing step for polishing the surface of the wafer, a technique capable of obtaining a more accurate flatness is required.

In the polishing step, a polishing liquid (slurry) in which free abrasive grains are suspended is supplied dropwise, and a work (semiconductor wafer) is appropriately directed toward a polishing surface of a surface plate or a polishing pad attached to the upper surface thereof. The work is polished by the relative motion given between the work and the surface plate or the polishing pad while being pressed by the load.

When the polishing surface of the platen or polishing pad is worn by the polishing liquid with the lapse of processing time,
It gradually loses its flatness and has a very small but certain degree of curvature. Since the shape of the polished surface is transferred to the surface shape of the work to be processed, the shape of the work obtained by polishing using such a polished surface gradually deviates from the required precision.

On the other hand, it is the most preferable from the viewpoint of accuracy that the polishing surface is constantly re-cut or the polishing pad is replaced with a new one to always maintain a true flat surface. Cannot be tolerated. For this reason, a technique has been considered in which, even when the polished surface is curved to some extent, the work is polished so as to fall within a required shape accuracy range by reducing the influence. Japanese Patent No. 2612012 discloses such a technique (hereinafter, referred to as a conventional technique).

FIG. 1 is a partial sectional view for explaining a main part of the above-mentioned conventional polishing apparatus. Polishing device 15
The table includes a platen 1, a carrier plate 2, a polishing liquid supply pipe 4, a pressure plate 8, an annular groove 10, an O-ring 11, and a pressure shaft 12.

The surface plate 1 has a flat polishing surface 1a on its upper surface, and is driven to rotate about a surface plate shaft 13 fixed to the surface plate 1. The pressing plate 8 has a pressing shaft 1 at its upper center.
2 are connected to each other, and are swingable and rotatable with respect to the pressing shaft 12. The pressure plate 8 also has a circular recess 8a on its lower surface, and a plurality of annular grooves 10 are provided concentrically with the pressure shaft 12 at the bottom of the recess 8a. An O-ring 11 having a circular cross section made of a soft elastic material such as rubber is mounted in one or more of the annular grooves 10.

The carrier plate 2 is accommodated in the recess 8a, and a plurality of semiconductor wafers 5 are generally fixed to the lower surface of the carrier plate 2 by appropriate means (eg, wax, vacuum suction, etc.). .

The wafer 5 is polished using the polishing apparatus 15 as follows. First, the O-ring 11 is mounted on one or more of the annular grooves 10, and the carrier plate 2 to which the plurality of wafers 5 are fixed is fitted in the recess 8a as shown in FIG. Then, the pressing shaft 12 connected to the upper portion of the pressing plate 8 is pressed downward by a pneumatic cylinder, a hydraulic cylinder, a weight, or the like, and the wafer 5 is pressed against the polishing surface 1 a of the platen 1.

In this state, the platen 1 is rotated about the axis O in the direction of arrow a while supplying the polishing liquid from the polishing liquid supply pipe 4 to the polishing surface 1a of the platen 1. At this time, the carrier plate 2 rotates in the direction of arrow b together with the pressure plate 8. Thus, the lower surface of the wafer 5 is polished by the interaction between the polishing liquid and the polishing surface 1a while the lower surface of the wafer 5 moves relative to the polishing surface 1a of the platen 1.

As described above, at the same time that the lower surface of the wafer 5 is polished, the polished surface 1a of the platen 1 also wears. Therefore, the flatness of the polished surface 1a is gradually lost, and the polished surface 1a has a very small degree of curvature. As a result, the degree of polishing of the wafer 5 is different between the outside and the inside of the carrier plate 2, so that the thickness is not uniform and the flatness is reduced. At this time, the downward pressing force of the carrier plate 2 is biased toward the inside or outside of the carrier plate 2 in accordance with the bending of the polishing surface 1a. Call.

In such a case, the dropped flatness can be recovered to some extent by re-selecting the annular groove 10 to which the O-ring 11 is to be mounted. That is, the force that the carrier plate 2 receives from the polishing surface 1a is
It is supported by a narrow ring-shaped contact surface between the O-ring 11 and the carrier plate 2. For this reason, since the carrier plate 2 deforms to some extent, if the position at which the O-ring 11 is mounted is changed, the surface pressure (polishing pressure) applied to the wafer 5 varies depending on the location, that is, it tends to push inward or push outward. Can be changed. Since the polishing pressure affects the amount of polishing, the dropped flatness can be offset by appropriately changing the mounting position (the annular groove 10) of the O-ring 11.

Although the above technique is very effective in maintaining flatness, since the annular groove 10 is located on the lower surface of the pressure plate 8, it is difficult to replace or change the position of the O-ring. There was a problem of accompanying. In other words, this operation is an operation in which the upper body or the arm is put into the narrow space formed by lifting the pressurizing plate 8 and the operation is performed upward from below, so that it is very difficult. There was a danger of worker injury due to the fall of No. 8.

[0014]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and it is possible to prevent the upper body or the arm from being inserted into the space below the lifted pressurizing plate. It is an object of the present invention to make it possible to replace an O-ring without working upward from above, and to make it possible to easily and safely replace the O-ring.

[0015]

The above object is achieved by the following means. That is, the polishing jig of the first invention comprises a disc portion, a cylindrical wall plate portion provided around the disc portion, and a concave portion formed by the disc portion and the cylindrical wall plate portion. A plurality of annular grooves formed concentrically with the disc portion are provided at the bottom of the place. Thereby, when attaching and adjusting the O-ring in the annular groove, the work can be performed by taking out the polishing jig, so that the work can be performed easily and safely.

According to a second aspect of the present invention, in the polishing jig of the first aspect, the plurality of annular grooves are for selectively mounting an O-ring made of an elastic material. By appropriately selecting the mounting location of the O-ring, it is possible to adjust the tendency of the middle press and the outside push of the polishing.

According to a third aspect of the present invention, in the polishing jig of the first or second aspect, the plurality of annular grooves are formed on both surfaces of the disk portion. For this reason, many annular grooves can be provided, and the range of options for mounting the O-ring is widened.

The polishing jig of the fourth invention is the polishing jig of any of the first to third inventions,
This polishing jig is formed by assembling one member or different members.

According to a fifth aspect of the present invention, there is provided a polishing apparatus comprising: a rotatable surface plate having a flat polishing surface; a pressure plate disposed above the surface plate; A polishing shaft, which is freely mounted, and a polishing liquid supply pipe for supplying a polishing liquid to the polishing surface, wherein the pressing plate is provided with any one of first to fourth polishing treatments; The tool recess is fitted. Thereby, when attaching and adjusting the O-ring in the annular groove, the work can be performed by taking out the polishing jig, so that the work can be performed easily and safely.

The polishing apparatus according to a sixth aspect of the present invention is the polishing apparatus according to the fifth aspect of the present invention, wherein a jumping skirt is provided around the pressure plate, so that the fitted polishing jig is provided. The polishing liquid is prevented from entering the recess.

A polishing apparatus according to a seventh aspect of the present invention is the polishing apparatus according to the sixth aspect, wherein the splash skirt has a flexible portion, and the flexible skirt can be turned up by the flexible portion. As well as
The flipped up state can be maintained. For this reason,
Thus, when the polishing jig is fitted to the pressure plate after the O-ring is mounted and adjusted in the annular groove, the field of view is not obstructed by the splash skirt, so that the work can be easily performed.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. Here, among the reference numerals used in FIG. 1 for describing the related art, in the case where they are substantially common to the embodiments described below, the same reference numerals are used.

FIG. 2 is a partial sectional view for explaining a main part of the polishing apparatus according to the embodiment of the present invention. FIG. 3 is an enlarged partial cross-sectional view of a part of FIG.
The polishing device 35 includes a surface plate 1, a carrier plate 2, a polishing liquid supply pipe 4, a pressure plate 8, and a pressure shaft 12.

A polishing pad 3 is attached to the upper surface of the surface plate 1, and the upper surface of the polishing pad 3 is a flat polishing surface 1a. The platen 1 to which the polishing pad 3 is attached is driven to rotate about a platen shaft 13. The pressurizing plate 8 is connected to a pressurizing shaft 12 at the upper center thereof, and is swingable and rotatable with respect to the pressurizing shaft 12.

The upper and lower surfaces of the polishing jig 28 are provided with a recess 28a and a recess 28b. In this recess (the recess 28b in the example of FIG. 2), the lower part of the pressure plate 8 is fitted. I have. A cloth between the lower surface of the pressure plate 8 and the bottom surface of the recess 28b is used to stabilize seating by avoiding contact between solids and to make it difficult for these surfaces to be polished by a polishing liquid that has entered by mistake. , A non-thick buffer sheet 23 such as a net or a plastic film is interposed.

A plurality of annular grooves 20 concentric with the carrier plate 2 are formed in the flat bottom of the recess 28a. An O-ring 21 having a circular cross section made of a soft elastic material such as rubber is mounted in one or more of the annular grooves 20.

The carrier plate 2 is accommodated in the lower recess 28a, and a plurality of semiconductor wafers 5 are usually placed on the lower surface of the carrier plate 2 by appropriate means (eg, wax, vacuum suction, etc.). Fixed.

As shown in FIG. 3, the pressing plate 8 is provided with a jump skirt 41 so as to surround the pressing plate 8. The repelling skirt 41 is attached to the pressing plate 8 by an appropriate fixing means such as screwing, bonding, fitting, or the like, and a mounting cylindrical portion 44 for blocking a polishing liquid entering from above the pressing plate 8. , Mounting cylinder 4
The polishing jig 28 further includes an umbrella-shaped portion 43 that is conical and spreads out continuously from the polishing jig 28. In addition,
In FIG. 2, the illustration of the jump skirt 41 is omitted.

The jumping skirt 41 may be integrally made of a flexible material such as rubber or synthetic resin.
Alternatively, at least the umbrella-shaped portion 43 can be made of such a flexible material, and the mounting cylindrical portion 44 or the repelling cylindrical portion 42 can be made of another material, for example, metal.
Since the umbrella-shaped portion 43 is made of a flexible material, the jumping skirt 41 can be easily flipped up as shown by a dotted line in FIG. Can be. Such a structure is employed to facilitate the operation as described later.

FIG. 4 shows an example of the polishing jig 28, and is an enlarged sectional view of a main part thereof. The polishing jig 28 includes a disk 281 made of aluminum or the like and a cylindrical wall plate 282 to which the disk 281 can be fitted. The polishing jig 28 is assembled by screwing a screw 283 into a screw hole 284 formed in a side surface of the disk 281. . It is not necessary to assemble the polishing jig 28 in this way, and the disc 281 and the cylindrical wall plate 282 can be formed integrally or cut out from the beginning.

A plurality of annular grooves 20 are formed concentrically with the polishing jig at the bottoms of the recesses 28a and 28b formed by the disk 281 and the cylindrical wall plate 282, respectively. 2 and 3, the annular groove 20 of the recess 28b is shown.
Are omitted. Since the diameters of the respective annular grooves 20 are different, O-rings 21 having respective circumferential lengths can be fitted in the respective annular grooves 20.

The wafer 5 is polished using the polishing apparatus 35 as follows. First, the polishing jig 28 is taken out, and the recess 28 a (or 28
b) is placed on an appropriate place such as a work desk with the top facing up, and the O-ring 21 is mounted in this state. This mounting is performed downward as in the case of other tasks normally performed by the worker, so it is much easier than before, and the upper body or arm is placed directly below the pressure plate that has been lifted as before. Without exposure, there is no danger of injury to workers in case of a fall.

The carrier plate 2 to which the plurality of wafers 5 are fixed is placed on the surface plate 1 and covered with the inverted recess 28a (or 28b) of the polishing jig 28. Since the O-ring 21 is located below, the polishing jig 28 is placed on the carrier plate 2 via the O-ring. Then, as shown in FIG. 2, the pressure plate 8 is fitted into the other upward recess 28b (or 28a). Prior to this operation, the jumping skirt 41 is turned up in advance as shown by the dotted line in FIG. Then, the bouncing cylinder 42 is raised upward, and the polishing jig 28
Can be visually recognized, and workability is improved.

The bouncing cylindrical portion 4 of the bouncing skirt 41
2 is again lowered as shown by the solid line, and the pressing shaft 12 connected to the upper part of the pressing plate 8 is pressed downward by a pneumatic cylinder, a hydraulic cylinder,
Is pressed against the polishing surface 1a of the polishing pad 3.

In this state, the platen 1 is rotated about the axis O in the direction of arrow a while the polishing liquid is supplied from the polishing liquid supply pipe 4 to the polishing surface 1a of the polishing pad 3. At this time,
The polishing jig 28 and the carrier plate 2 rotate together with the pressure plate 8 in the direction of arrow b. Thus, the wafer 5
The lower surface of the wafer 5 moves relative to the polishing surface 1a of the polishing pad 3, and the wafer 5
Is polished. With the passage of time, when the polished wafer 5 starts to have a middle-pressing tendency and an externally-pressing tendency, by appropriately selecting and adjusting the mounting place of the O-ring according to the procedure described above, these tendencies are reduced. Can be corrected.

When the supplied polishing liquid hits the polishing surface 1 a, the polishing liquid inevitably flies off. However, since the flying polishing liquid is blocked by the repelling skirt 41, the polishing jig 28 has a recess 2.
There is no risk of intrusion into 8a or 28b. Even if the polishing liquid accidentally enters the recess 28a or 28b, the pressure plate 8
And the bottom surface of the recess 28b (or 28a) of the polishing jig 28 are not polished by the polishing liquid.

The polishing jig 28 is vertically symmetrical except for the annular groove 20, and the radial positions of the annular groove are alternately arranged vertically.
For this reason, either surface of the polishing jig 28 and the annular groove 20 can be selected according to the required size of the O-ring 21. Note that the annular groove 20 does not necessarily need to be provided on both sides of the polishing jig 28, and may be provided on only one side.

If there is no problem such as intrusion of the polishing liquid as described above, the jumping skirt 41 is not particularly essential, and may not be provided in some cases. Furthermore, it is preferable to provide the buffer sheet 23, but it is not essential. Further, as shown in FIG. 1 which is used for explaining the prior art, the polishing jig of the present invention is also used in a polishing apparatus in which the upper surface of the surface plate 1 is used as a polishing surface and the polishing pad 3 is not used. It goes without saying that it can be used.

[0039]

According to the present invention, the O-ring can be exchanged without putting the upper body or the arm in the space below the lifted pressure plate and without working upward from below. This also has the effect that the O-ring can be easily and safely replaced.

Since the polishing jig of the present invention has annular grooves on both surfaces, it is possible to provide many annular grooves and to use an optimal O-ring.
In addition, because the pressure plate has a jumping skirt,
Polishing liquid does not enter between the pressure plate and the polishing jig,
There is an effect that there is no possibility that these are polished.
Furthermore, even if the polishing liquid inadvertently intrudes, the buffer sheet is interposed, so that there is an effect that the polishing action hardly occurs. Furthermore, since the jumping skirt can be flipped up and can be maintained even if it is lifted up, it does not hinder the work when replacing the polishing jig. It works.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view for explaining a main part of a conventional polishing apparatus.

FIG. 2 is a partial cross-sectional view for explaining a main part of the polishing apparatus according to the embodiment of the present invention.

FIG. 3 is an enlarged partial cross-sectional view of a part of FIG. 2;

FIG. 4 is an enlarged sectional view showing an example of a main part of the polishing jig 28 according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 surface plate 2 carrier plate 3 polishing pad 4 polishing liquid supply pipe 5 semiconductor wafer 8 pressure plate 10, 20 annular groove 11, 21 O-ring 12 pressure shaft 13 surface plate shaft 15, 35 polishing device 1a polishing surface 23 buffer sheet 28 Polishing jig 41 Bouncing skirt 42 Bouncing cylindrical portion 43 Umbrella-shaped portion 44 Mounting cylindrical portion 8a, 28a, 28b Recess 281 Disk 282 Cylindrical wall plate 283 Screw 284 Screw hole O axis

Claims (7)

[Claims] 1. A disk portion, a cylindrical wall plate portion provided around the disk portion, and a disk formed on the bottom of a recess formed by the disk portion and the cylindrical wall plate portion. A polishing jig comprising a portion and a plurality of annular grooves formed concentrically. 2. The polishing jig according to claim 1, wherein the plurality of annular grooves are for selectively mounting an O-ring made of an elastic material. 3. The polishing jig according to claim 1, wherein said plurality of annular grooves are formed on both surfaces of said disc portion. 4. The polishing jig according to claim 1, wherein the polishing jig is formed by integrally or differently assembling the polishing jig. Utensils. 5. A rotatable surface plate having a flat polishing surface, a pressure plate disposed above the surface plate, and a pressure shaft on which the pressure plate is swingably and rotatably mounted. A polishing apparatus comprising a polishing liquid supply pipe for supplying a polishing liquid to the polishing surface, wherein the pressurizing plate is a polishing jig according to any one of claims 1 to 4. A polishing apparatus characterized in that a recess is fitted therein. 6. A repelling device according to claim 5, wherein a splash is provided around the pressure plate to prevent a polishing liquid from entering a recess of the fitted polishing jig. A polishing apparatus comprising a skirt. 7. The polishing apparatus according to claim 6, wherein the jumping skirt has a flexible portion, and the flexible skirt can be turned up by the flexible portion and can be turned up. A polishing apparatus characterized in that the polishing apparatus can be maintained.